KR20230156686A - Epoxy resin mixture and method for producing the same, epoxy resin composition and cured product thereof - Google Patents

Abstract

The present invention provides an epoxy resin mixture, an epoxy resin composition, and a cured product thereof that exhibit high heat resistance and high elastic modulus.
An epoxy resin mixture containing an epoxy resin represented by the following formula (1) and an epoxy compound represented by the following formula (2).
[Formula 1]

(In equation (1), n is the number of repetitions and represents a real number from 1 to 20.)
[Formula 2]

Description

Epoxy resin mixture and method for producing the same, epoxy resin composition and cured product thereof

The present invention relates to insulating materials for electrical and electronic components (high-reliability semiconductor encapsulation materials, etc.), laminated boards (printed wiring boards, build-up boards, etc.) and various composite materials including FRP (fiber reinforced plastic), adhesives, paints, etc., among others, laminated boards, etc. It relates to an epoxy resin mixture and an epoxy resin composition that are useful for uses and provide a curable resin composition useful for laminated boards with metal foil, insulating materials for build-up boards, flexible board materials, etc.

Epoxy resins are widely used in fields such as electrical and electronic components, structural materials, adhesives, and paints due to their workability and the excellent electrical properties, heat resistance, adhesiveness, and water absorption resistance of their cured products.

Recently, in the field of semiconductor-related materials, power semiconductors that can handle higher voltages or currents than conventional semiconductors have been developed and used to improve functionality and performance. Power semiconductors are mainly used for power conversion, such as changing voltage or frequency or switching between direct current and alternating current, thereby precisely turning motors, sending generated electricity to the transmission grid without waste, and providing stable power to home appliances and electrical appliances. can be supplied.

Since power semiconductors handle very large amounts of power, they generate heat and become high in temperature when used, which can cause malfunctions. To ensure long-term high-temperature operation of power semiconductors, a reliability test called a cold-heat cycle test that repeats -55°C to 150°C over 1,000 cycles is performed. Therefore, heat resistance of 150°C or higher is required for resin materials for power semiconductors (Patent Documents 1 to 4).

In the semiconductor field, in addition to increasing the functionality and performance of power semiconductors, the development of package substrates necessary for mounting chips is underway, leading to thinning. As package substrates become thinner, rigidity becomes necessary, and substrate materials that lack rigidity cannot withstand bending, leading to breakage. For this reason, resin materials widely used in substrate materials are required to have a high elastic modulus.

In addition to package substrates, there are many resin materials that require a high modulus of elasticity, one of which is CFRP (carbon fiber reinforced plastic). CFRP is filled with resin material within the carbon fiber, so when a load is applied, stress is propagated to the fiber through the resin, so many parts of the carbon fiber can effectively bear the load at the same time. Since the resin material used at this time has a high elastic modulus, bending of the carbon fiber due to stress generated when a load is applied can be suppressed, which leads to the development of the strength of CFRP. If the elastic modulus of the resin material is low, the carbon fibers are easily bent due to stress, and the strength of CFRP cannot be expressed well, leading to breakage. Therefore, it is desirable for the resin material used in CFRP to have at least a slightly higher elastic modulus.

Patent Document 5 discloses a resin composition combining an epoxy resin with a neopentyl glycol, 1,4-butanediol, and 1,6-hexanediol skeleton and a bisphenol A type epoxy resin, and shows excellent heat resistance and elastic modulus, but the heat resistance is poor. It does not reach 150°C, and the elastic modulus cannot be said to be a sufficient value.

Patent Document 1: Japanese Patent Publication No. 2021-019123 Patent Document 2: Japanese Patent Publication No. 2021-031323 Patent Document 3: Japanese Patent Publication No. 2020-035721 Patent Document 4: Japanese Patent Publication No. 2021-027150 Patent Document 5: International Publication No. 2020/250957

The present invention was made in consideration of this situation, and its purpose is to provide an epoxy resin mixture, an epoxy resin composition, and a cured product thereof that exhibit high heat resistance and high elastic modulus.

As a result of extensive research, the present inventors discovered that by containing a specific ratio of an epoxy compound with a specific structure to an epoxy resin with a specific structure, the cured product has high heat resistance and high elastic modulus, and came to complete the present invention. .

That is, the present invention is shown in [1] to [5] below.

[One]

An epoxy resin mixture containing an epoxy resin represented by the following formula (1) and an epoxy compound represented by the following formula (2).

(In equation (1), n is the number of repetitions and represents a real number from 1 to 20.)

[2]

In gas chromatography analysis, when the content of the epoxy resin in which n in the formula (1) is 1 is 100 area%, the content of the epoxy compound represented by the formula (2) is 1.0 to 10.0 area%. The epoxy resin mixture described in [1].

[3]

An epoxy resin composition containing the epoxy resin mixture according to the preceding item [1] or [2] and a curing agent.

[4]

A cured product obtained by curing the epoxy resin composition described in the preceding paragraph [3].

[5]

A method for producing an epoxy resin mixture according to the preceding item [1] or [2], which is obtained by reacting epichlorohydrin with a phenol resin represented by the following formula (3) and a phenol compound represented by the following formula (4).

(In equation (3), n is the number of repetitions and represents a real number from 1 to 20.)

According to the present invention, it is possible to provide an epoxy resin, an epoxy resin composition, and a cured product using the same whose cured product has high heat resistance and high elastic modulus. Therefore, it is useful for power semiconductors, circuit boards, FRP, etc.

Figure 1 shows the GPC chart of Example 2.
Figure 2 shows the GPC chart of Example 3.
Figure 3 shows the GPC chart of Synthesis Example 1.
Figure 4 shows the GC charts of Examples 2 and 3 and Synthesis Example 1.

The epoxy resin mixture of the present invention contains an epoxy resin represented by the following formula (1) and an epoxy compound represented by the following formula (2).

(In equation (1), n is the number of repetitions and represents a real number from 1 to 20.)

In the above formula (1), the value of n can be determined by measurement using gel permeation chromatography (GPC, detector: RI). n is usually a real number from 1 to 20, but it is preferably 1 to 10, and more preferably 1 to 5. When n becomes greater than 20, the molecular weight increases and the viscosity becomes high, which reduces processability.

Additionally, the average value of n can be calculated from the number average molecular weight determined by gel permeation chromatography (GPC, detector: RI) or the area ratio of each separated peak. The average value of n is preferably 1 to 10, more preferably 1.1 to 10, and particularly preferably 1.1 to 5.

The preferred range of the epoxy equivalent weight of the epoxy resin mixture containing the epoxy resin represented by the formula (1) and the epoxy compound represented by the formula (2) is 250 g/eq. More than 400g/eq. less than, more preferably 280 g/eq. More than 350g/eq. less than, particularly preferably 290 g/eq. More than 320g/eq. It is less than. The epoxy equivalent weight of the epoxy resin mixture is 250 g/eq. If it is less than that, the crosslinking density increases and heat resistance improves, but it becomes hard and brittle, resulting in a decrease in mechanical strength, which is not preferable. Additionally, the epoxy equivalent weight of the epoxy resin mixture is 600 g/eq. If it is above this, the crosslinking density decreases and the brittleness of the cured product improves, but it is not preferable because it causes a decrease in heat resistance. If the epoxy equivalent is appropriate, the heat resistance of the cured product can be improved without causing a decrease in mechanical strength.

In the present invention, the epoxy equivalent is measured by the method described in JIS K-7236.

The preferred range of softening point of the epoxy resin mixture of the present invention is 60 to 80°C, more preferably 65 to 70°C. If the softening point is within the above range, handling properties are excellent because the resins do not block each other at room temperature.

The content of the epoxy compound represented by the above formula (2) can be measured by GC (gas chromatography) analysis and can be confirmed from the area% of the detected peak. The GC analysis of the present invention is performed by the method described in the Examples described later.

In GC analysis, when the content of the epoxy resin in which n in the formula (1) is 1 is 100 area%, the content of the epoxy compound represented by the formula (2) is preferably 1.0 to 10.0 area%. 1.0 to 8.0 area% is more preferable, 1.0 to 6.0 area% is more preferable, 2.0 to 6.0 area% is particularly preferable, and 2.0 to 4.0 area% is most preferable. Free volume occurs in the three-dimensional network of the cured product of the epoxy resin mixture. Since the epoxy compound represented by the above formula (2) has only one functional group, if its content is 1.0 area% or more, the free volume can be reduced, making it difficult for the three-dimensional network to move, improving heat resistance and elastic modulus. If the content of the epoxy compound represented by the formula (2) is greater than 10.0 area%, the free volume decreases, but since the epoxy compound represented by the formula (2) that cannot enter the free volume exists in excess, there are many low molecular weight components. This results in lower heat resistance and elastic modulus. Therefore, it is preferable that the content of the epoxy compound represented by the above formula (2) is within the above range.

The epoxy resin mixture of the present invention has excellent heat resistance and elastic modulus. The heat resistance is preferably 150°C or higher, more preferably 155°C or higher, and particularly preferably 160°C or higher. If the heat resistance is low, if it is used in a place where it operates at a higher temperature for a longer period of time than before, such as in a power device, the molecular movement may increase, which may lead to damage. In addition, thin substrates such as package substrates require rigidity, that is, an elastic modulus of the cured product, and if the rigidity is low, the substrate is likely to bend and may be damaged. For this reason, thin substrates are required to have a high elastic modulus. The elastic modulus of the epoxy resin material is preferably 2.8 GPa or more, and more preferably 2.9 GPa or more in a bending test at 30°C.

The epoxy resin represented by the formula (1) and the epoxy compound represented by the formula (2) are the phenol resin represented by the formula (3) below, the phenol compound represented by the formula (4) below, and epichlorohydrin. It can be obtained by reaction.

(In equation (3), n is the number of repetitions and represents a real number from 1 to 20.)

The value and preferred range of n in equation (3) are the same as in equation (1) above.

A method for synthesizing the phenol resin represented by the above formula (3) includes the reaction between phenol and 4,4'-bischloromethylbiphenyl, and the amount of 4,4'-bischloromethylbiphenyl used in this case is phenol It is usually in the range of 1 to 9 moles, preferably 2 to 8 moles, per 10 moles.

Specific examples of basic substances that can be used in the above reaction include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, alkaline earth metal hydroxides such as magnesium hydroxide, calcium hydroxide, and barium hydroxide, and alkaline earth metal oxides such as magnesium oxide and calcium oxide. , sodium acetate, potassium acetate, sodium oxalate, potassium oxalate, sodium formate, potassium formate, calcium acetate, magnesium acetate, ammonium acetate, sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, Ammonium bicarbonate, trisodium citrate, tripotassium citrate, sodium tartrate, potassium tartrate, sodium phosphate, sodium tripolyphosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, sodium methoxide, sodium ethoxide, potassium-tert-butoxide. , alkali metal methoxides such as potassium ethoxide, sodium phenoxide, potassium phenoxide, etc., but are not limited to these. In addition, these may be used individually, or two or more types may be used together. The amount of these basic substances used is usually 0.02 to 2.0 mol, preferably 0.05 to 2.0 mol, per 1 mol of 4,4'-bischloromethylbiphenyl.

Specific examples of solvents that can be used in the above reaction include alcohols such as methanol, ethanol, and propanol, ketones such as methyl ethyl ketone and methyl isobutyl ketone, diethylene glycol, and acetic acid, but are not limited to these. In addition, these may be used individually, or two or more types may be used together. The amount of these used is usually in the range of 5 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of phenol.

In the above reaction, the phenol compound represented by the above formula (4) can be obtained by using toluene together with the above solvent. The amount of toluene used is usually in the range of 5 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of phenol. When more than 200 parts by weight of toluene is used, a large amount of the phenolic compound represented by the above formula (4) is produced, and as a result, a large amount of the epoxy compound represented by the above formula (2) is produced, resulting in a significant decrease in heat resistance. On the other hand, when less than 5 parts by weight of toluene is used, the amount of the phenol compound represented by the formula (4) is reduced, and as a result, the amount of the epoxy compound represented by the formula (2) is reduced, resulting in a low elastic modulus. Therefore, it is preferable to use toluene within the above range.

In the above reaction, it is generally preferable to add phenol and the basic substance and gradually add 4,4'-bischloromethylbiphenyl to it. The temperature at that time is usually 50 to 150°C, preferably 60 to 120°C, and is usually 0.5 to 10 hours, preferably 1 to 4 hours. When the reaction is carried out at a temperature of less than 50°C, it is difficult for toluene to react, that is, the production of the epoxy compound represented by the above formula (2) becomes difficult. If the temperature exceeds 150°C, toluene volatilizes and does not contribute to the reaction. After the addition of 4,4'-bischloromethylbiphenyl is completed, the reaction is usually carried out at 50 to 150°C, preferably 60 to 120°C, for another 0.5 to 10 hours, preferably 1 to 5 hours. Additionally, if the pH of the reaction solution is not acidic, the progress of the reaction may be hindered and polymerization may not occur. In this case, acidic substances such as p-toluenesulfonic acid, hydrochloric acid, and sulfuric acid are added to the reaction system. After completion of the reaction, excess phenol is distilled off under heating and reduced pressure. After that, it is usually dissolved in a water-insoluble solvent, repeatedly washed with water to remove the salt, and the solvent is distilled off to obtain the phenol resin represented by the formula (3) and the phenolic compound represented by the formula (4).

Next, the reaction for obtaining the epoxy resin mixture of the present invention will be described. The epoxy resin represented by the formula (1) and the epoxy compound represented by the formula (2) are respectively a phenol resin represented by the formula (3) and a phenolic compound represented by the formula (4) with epichlorohydrin and It is obtained by reaction.

Epichlorohydrin is easily available in the market. The amount of epichlorohydrin used is usually 3.0 to 10 mol, preferably 3.5 to 8.0 mol, more preferably 4.0 to 7.0 mol, based on 1 mol of hydroxyl group of the raw material phenol resin.

In the above reaction, an alkali metal hydroxide can be used as a catalyst to promote the epoxidation process. Alkali metal hydroxides that can be used include sodium hydroxide, potassium hydroxide, etc., and solid materials or aqueous solutions thereof may be used. However, in the present invention, the use of solid products shaped into flakes is preferred, especially from the viewpoint of solubility and handling. desirable. The amount of alkali metal hydroxide used is usually 0.90 to 1.50 mole per mole of hydroxyl group of the raw material phenol resin.

Additionally, in order to promote the reaction, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, and trimethylbenzylammonium chloride may be added as a catalyst. The amount of quaternary ammonium salt used is usually 0.0009 to 0.15 mole per mole of hydroxyl group in the raw material phenol mixture.

The reaction temperature is usually 30 to 90°C, preferably 35 to 80°C. In particular, in the present invention, 50°C or higher is preferable for higher purity epoxidation. The reaction time is usually 0.5 to 10 hours, preferably 1 to 8 hours, and particularly preferably 1 to 4 hours. If the reaction time is short, the reaction does not proceed, and if the reaction time is long, by-products are generated, which is not preferable.

After washing the reactants of these epoxidation reactions with water, epichlorohydrin, solvent, etc. are removed under heating and reduced pressure without washing with water. Additionally, in order to make an epoxy resin with less hydrolyzable halogen, the recovered epoxy resin is mixed with a ketone compound having 4 to 7 carbon atoms (for example, methyl isobutyl ketone, methyl ethyl ketone, cyclopentanone, cyclohexanone, etc.). ) as a solvent and adding an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide to carry out the reaction to ensure ring closure. In this case, the amount of alkali metal hydroxide used is usually 0.01 to 0.3 mol per mole of hydroxyl group of the raw material phenol resin used for epoxidation, the reaction temperature is usually 50 to 120°C, and the reaction time is usually 0.5 to 2 hours.

After completion of the reaction, the produced salt is removed by filtration, washing with water, etc., and the solvent is further distilled off under heating and reduced pressure to obtain the epoxy resin mixture of the present invention.

The epoxy resin composition of the present invention contains a curing agent. Examples of curing agents that can be used include phenol-based curing agents, acid anhydride-based curing agents, amide-based curing agents, and amine-based curing agents.

In the epoxy resin composition of the present invention, a phenol-based curing agent is particularly preferred because it can achieve a good balance of heat resistance and thermal stability of the cured resin. Examples of phenol-based curing agents include phenol novolak resin, cresol novolak resin, and phenol aralkyl resin;

Polyhydric phenols (bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, terpenediphenol, 4,4'-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, 3,3', 5,5 '-Tetramethyl-(1,1'-biphenyl)-4,4'-diol, hydroquinone, resorcin, naphthalenediol, tris-(4-hydroxyphenyl)methane and 1,1,2,2- tetrakis(4-hydroxyphenyl)ethane, etc.); Phenols (e.g., phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) and aldehydes (formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, o- phenol resins obtained by condensation with hydroxybenzaldehyde, furfural, etc.), ketones (p-hydroxyacetophenone, o-hydroxyacetophenone, etc.), or dienes (dicyclodiendiene, tricyclopentadiene, etc.); The above phenols and substituted biphenyls (4,4'-bis(chloromethyl)-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl, etc.), or Phenolic resins obtained by polycondensation with substituted phenyls (1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl)benzene, and 1,4-bis(hydroxymethyl)benzene; the above phenols and/or modified products of the above phenol resins; halogenated phenols such as tetrabromobisphenol A and brominated resins.

Acid anhydride-based hardeners include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnagic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. I can hear it.

Examples of the amide-based curing agent include dicyandiamide or a polyamide resin synthesized from a dimer of linolenic acid and ethylenediamine.

Amine-based hardeners include 3,3'-diaminodiphenylsulfone (3,3'-DDS), 4,4'-diaminodiphenylsulfone (4,4'-DDS), and diaminodiphenylmethane (DDM). , 3,3'-diisopropyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl -5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diisopropyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3' -di-t-butyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane, 3 ,3'-Diisopropyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-5,5'-diethyl-4,4' -Diaminodiphenylmethane, 3,3',5,5'-tetraisopropyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-5,5'-diiso Propyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetra-t-butyl-4,4'-diaminodiphenylmethane, diaminodiphenyl ether (DADPE), bis Aniline, benzyldimethylaniline, 2-(dimethylaminomethyl)phenol (DMP-10), 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30), 2,4,6-tris(dimethylaminomethyl) ) 2-ethylhexanoic acid ester of phenol, etc. can be used. In addition, aniline novolac, orthoethylaniline novolac, aniline resin obtained by reaction of aniline and xylylene chloride, aniline and substituted biphenyls (4,4'-bis(chloromethyl)-1,1'-bi phenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl, etc.), or substituted phenyls (1,4-bis(chloromethyl)benzene, 1,4-bis(methoxymethyl) and aniline resins obtained by polycondensation with benzene, 1,4-bis(hydroxymethyl)benzene, etc.

In the epoxy resin composition of the present invention, the amount of curing agent used is preferably 0.7 to 1.2 equivalents per equivalent of epoxy group of the epoxy resin. If the amount is less than 0.7 equivalents based on 1 equivalent of the epoxy group, or if it exceeds 1.2 equivalents, there is a risk that curing will be incomplete and good cured properties may not be obtained.

Additionally, in the epoxy resin composition of the present invention, a curing accelerator may be added as needed. The gelation time can also be adjusted by using a curing accelerator. Examples of curing accelerators that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole, 2-(dimethylaminomethyl)phenol, and 1,8 -tertiary amines such as diaza-bicyclo(5,4,0)undecene-7, phosphines such as triphenylphosphine, and metal compounds such as tin octylate. The curing accelerator is used in an amount of 0.01 to 5.0 parts by weight based on 100 parts by weight of the epoxy resin.

In the epoxy resin composition of the present invention, other epoxy resins may be blended, and specific examples include phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, dihyde Polycondensates of aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.), Phenols and various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene , isoprene, etc.), polycondensates of phenols and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, etc.), phenols and substituted biphenyls (4,4'-bis(chlormethyl )-1,1'-biphenyl and 4,4'-bis(methoxymethyl)-1,1'-biphenyl, etc.), or substituted phenyls (1,4-bis(chloromethyl)benzene, 1, Phenolic resins obtained by polycondensation with 4-bis(methoxymethyl)benzene and 1,4-bis(hydroxymethyl)benzene, etc., polycondensates of bisphenols and various aldehydes, glycidylated alcohols, etc. Glycidyl ether-based epoxy resins, alicyclic epoxy resins such as 4-vinyl-1-cyclohexene diepoxide and 3,4-epoxycyclohexylmethyl-3,4'-epoxycyclohexanecarboxylate, Examples include glycidylamine-based epoxy resins, such as tetraglycidyldiaminodiphenylmethane (TGDDM) and triglycidyl-p-aminophenol, and glycidyl ester-based epoxy resins, but commonly used If it is an epoxy resin, it is not limited to these.

Known additives can be added to the epoxy resin composition of the present invention as needed. Specific examples of additives that can be used include polybutadiene and its modified products, modified products of acrylonitrile copolymer, polyphenylene ether, polystyrene, polyethylene, polyimide, fluororesin, maleimide-based compounds, cyanate ester-based compounds, and silicone. Gel, silicone oil, inorganic fillers such as silica, alumina, calcium carbonate, quartz powder, aluminum powder, graphite, talc, clay, iron oxide, titanium oxide, aluminum nitride, asbestos, mica, glass powder, fillers such as silane coupling agent. surface treatment agents, mold release agents, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green.

Known maleimide-based compounds can be blended into the epoxy resin composition of the present invention as needed. Specific examples of maleimide compounds that can be used include 4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, m-phenylenebismaleimide, 2,2'-bis[4-(4-maleimidephenoc) C) phenyl] propane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylenebismaleimide, 4,4 '-Diphenyletherbismaleimide, 4,4'-diphenylsulfonebismaleimide, 1,3-bis(3-maleimidephenoxy)benzene, 1,3-bis(4-maleimidephenoxy)benzene These may be mentioned, but are not limited to these. These may be used individually, or two or more types may be used together. When blending a maleimide-based compound, a curing accelerator is blended as needed; however, the curing accelerator described above or a radical polymerization initiator such as an organic peroxide or an azo compound can be used.

The epoxy resin composition of the present invention can be made into a varnish-like composition (hereinafter simply referred to as varnish) by adding an organic solvent. Solvents used include, for example, amides such as γ-butyrolactone, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and N,N-dimethylimidazolidinone. Solvents, sulfones such as tetramethylene sulfone, ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether monoacetate, and propylene glycol monobutyl ether. , ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone, and aromatic solvents such as toluene and xylene. The solvent is used in a range where the solid content concentration excluding the solvent in the obtained varnish is usually 10 to 80% by weight, preferably 20 to 70% by weight.

Next, the cured product, resin sheet, prepreg, and FRP of the present invention will be explained.

The epoxy resin composition of the present invention may be applied to one or both sides of a support substrate and used as a resin sheet. Application methods include, for example, a molding method, a method of extruding resin from a nozzle or die using a pump or extruder and adjusting the thickness with a blade, a method of adjusting the thickness by calendering with a roll, or spraying using a spray, etc. Methods, etc. may be mentioned. Additionally, in the step of forming the layer, the epoxy resin composition may be performed while being heated in a temperature range that can avoid thermal decomposition. Additionally, rolling treatment, grinding treatment, etc. may be performed as needed. Examples of the supporting substrate include porous substrates made of paper, cloth, non-woven fabric, etc., plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, or sheets, nets, foams, metal foils, and laminates thereof. Thin leaf bodies and the like can be mentioned, but are not limited to these. The thickness of the support base material is not particularly limited and is appropriately determined depending on the intended use.

The prepreg of the present invention can be obtained by heating and melting the epoxy resin composition and/or the resin sheet of the present invention to lower the viscosity and impregnating the fiber base material.

Additionally, the prepreg of the present invention can be obtained by impregnating a fiber base with a varnish-like epoxy resin composition and heating and drying it. After cutting and laminating the prepreg into the desired shape, the FRP of the present invention can be obtained by heat-curing the epoxy resin composition while applying pressure to the laminate using a press molding method, autoclave molding method, sheet winding molding method, etc. Additionally, copper foil or organic film can also be laminated when lamination of the prepreg.

Furthermore, the FRP molding method of the present invention can be obtained by molding by a known method other than the above method. For example, a carbon fiber base material (usually carbon fiber fabric is used) is cut, laminated, and shaped to produce a preform (a preform before impregnating resin), the preform is placed in a mold, the mold is closed, and resin is injected. You can also use resin transfer molding technology (RTM method), which involves impregnating and curing the preform, then opening the mold and taking out the molded product.

In addition, a type of RTM method, such as VaRTM method, SCRIMP (Seeman's Composite Resin Infusion Molding Process) method, and the resin supply tank described in Japanese Patent Application No. 2005-527410 is evacuated to a pressure lower than atmospheric pressure and circular compression is used. In addition, the CAPRI (Controlled Atmosphereic Pressure Resin Infusion) method can be used to more appropriately control the resin injection process, especially the VaRTM method, by controlling the net molding pressure.

Furthermore, a film stacking method of inserting a fiber base into a resin sheet (film), a method of attaching powder-like resin to a reinforced fiber base to improve impregnation, and a fluidized bed or fluid slurry method in the process of mixing the resin into the fiber base. A molding method (Powder Impregnated Yarn) or a method of mixing resin fibers into a fiber substrate can also be used.

Examples of carbon fibers include acrylic-based, pitch-based, and rayon-based carbon fibers, and among them, acrylic-based carbon fibers with high tensile strength are preferably used. As the form of carbon fiber, flexible yarns, untwisted yarns, and untwisted yarns can be used, but since the formability and strength characteristics of the fiber-reinforced composite material are well balanced, natural twisted yarns or untwisted yarns are preferably used.

Example

The present invention will be described in more detail below with reference to examples. The materials, processing content, processing sequence, etc. shown below can be changed appropriately as long as they do not deviate from the spirit of the present invention. Accordingly, the scope of the present invention is not to be construed as limited by the specific examples shown below.

Various analysis methods were performed under the following conditions.

ㆍEpoxy equivalent

Measured by the method described in JIS K-7236, and the unit is g/eq.

ㆍYeonhwa branch

Measured by a method based on JIS K-7234, the unit is ℃.

ㆍMel viscosity

ICI melt viscosity (150°C) is measured by the corn plate method, and the unit is Pa·s.

ㆍGPC (Gel Permeation Chromatography) analysis

Maker: Waters

Device: waters alliance e2695

Column: Guard column SHODEX GPC KF-601 (2 pcs.), KF-602 KF-602.5, KF-603

Flow rate: 1.23ml/min.

Column temperature: 25℃

Solvent used: THF (tetrahydrofuran)

Detector: RI (parallel refraction detector)

ㆍGC (gas chromatography) analysis

Manufacturer: Agilent Technology Co., Ltd.

Device: HP6890

Column: DB-5HT 30m - 0.25mm - 0.10μm

Carrier gas: He 1.2mL/min.

Oven: 150℃-10℃/min. -350℃(40min.)

Inlet: split(30:1), 330℃

Detector: FID

Detector temperature: 350℃

[Example 1]

195 parts by weight of phenol, 50 parts by weight of flake-shaped sodium hydroxide, 20 parts by weight of methanol, and 40 parts by weight of toluene were added to a flask equipped with a stirrer, reflux condenser, and stirring device, stirred, dissolved, and heated to bring the temperature to 100°C. While maintaining , 151 parts by weight of 4,4'-bischloromethylbiphenyl was added continuously over 4 hours. After the addition was completed, 11 parts by weight of p-toluenesulfonic acid was added, and reaction was performed for an additional 3 hours at the same temperature. After completion of the reaction, by-producing sodium chloride was removed by washing with water, excess phenol was distilled off from the oil layer under heating and reduced pressure, and 400 parts by weight of methyl isobutyl ketone was added to the residue to dissolve it. After repeatedly washing this resin solution with water until the washing liquid became neutral, methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure to obtain 180 parts by weight of phenol resin (P1).

[Example 2]

With respect to 107 parts by weight of the phenol resin (P1) obtained in Example 1, 230 parts by weight of epichlorohydrin and 60 parts by weight of dimethyl sulfoxide were added to a reaction vessel, and after heating, stirring, and dissolution, flakes were formed while maintaining the temperature at 45°C. 21 parts by weight of sodium hydroxide was added continuously over 2 hours. After the addition of sodium hydroxide was completed, the reaction was performed at 45°C for 2 hours and at 70°C for an additional hour. Subsequently, washing with water was repeated to remove the passive salt and dimethyl sulfoxide, and then excess epichlorohydrin was distilled off from the oil layer under heating and reduced pressure, and 300 parts by weight of methyl isobutyl ketone was added to the residue to dissolve it. This methyl isobutyl ketone solution was heated to 70°C, 10 parts by weight of 30% aqueous sodium hydroxide solution was added, and the mixture was allowed to react for 1 hour. After that, the reaction solution was repeatedly washed with water until the washing solution became neutral. Next, 130 parts by weight of the epoxy resin mixture (EP1) was obtained by distilling methyl isobutyl ketone from the oil layer under heating and reduced pressure. The GPC chart of the epoxy resin mixture (EP1) is shown in Figure 1. The epoxy equivalent weight of the epoxy resin mixture (EP1) was 312 g/eq., the softening point was 66.9°C, and the ICI melt viscosity was 0.25 Pa·s (150°C). In the GC analysis, when the content of the epoxy resin (peaks at 24.8 minutes, 26.5 minutes, and 28.4 minutes in Figure 4A) in which n in the formula (1) is 1 is 100 area%, The content of the epoxy compound (peaks at 21.1 and 22.1 minutes in Fig. 4A) was 6.0 area%.

[Example 3]

In Example 1, 230 parts by weight of epichlorohydrin and 60 parts by weight of dimethyl sulfoxide were added to the reaction vessel for 107 parts by weight of phenol resin (P3) synthesized in the same manner as in Example 1 except that toluene was used in an amount of 20 parts by weight. After heating, stirring, and dissolving, 21 parts by weight of flake-shaped sodium hydroxide was added continuously over 2 hours while maintaining the temperature at 45°C. After the addition of sodium hydroxide was completed, the reaction was performed at 45°C for 2 hours and at 70°C for an additional hour. Subsequently, washing with water was repeated to remove the passive salt and dimethyl sulfoxide, and then excess epichlorohydrin was distilled off from the oil layer under heating and reduced pressure, and 300 parts by weight of methyl isobutyl ketone was added to the residue to dissolve it. This methyl isobutyl ketone solution was heated to 70°C, 10 parts by weight of 30% aqueous sodium hydroxide solution was added, and the mixture was allowed to react for 1 hour. After that, the reaction solution was repeatedly washed with water until the washing solution became neutral. Next, methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure to obtain 133 parts by weight of an epoxy resin mixture (EP2). The GPC chart of the epoxy resin mixture (EP2) is shown in Figure 2. The epoxy equivalent weight of the epoxy resin mixture (EP2) was 296 g/eq., the softening point was 69.8°C, and the ICI melt viscosity was 0.33 Pa·s (150°C). In GC analysis, when the content of the epoxy resin (peaks at 24.9 minutes, 26.5 minutes, and 28.3 minutes in Figure 4B) with n of the formula (1) is 1 is 100 area%, the epoxy compound represented by the formula (2) ( The content of peaks at 21.1 and 22.1 minutes in Figure 4A was 3.5 area%.

[Synthesis Example 1]

In Example 1, 230 parts by weight of epichlorohydrin and 60 parts by weight of dimethyl sulfoxide were added to a reaction vessel for 107 parts by weight of phenol resin (P2) synthesized in the same manner except that 0 parts by weight of toluene was added and heated. After stirring and dissolving, 21 parts by weight of flake-shaped sodium hydroxide was continuously added over 2 hours while maintaining the temperature at 45°C. After the addition of sodium hydroxide was completed, the reaction was performed at 45°C for 2 hours and at 70°C for an additional hour. Subsequently, washing with water was repeated to remove the passive salt and dimethyl sulfoxide, and then excess epichlorohydrin was distilled off from the oil layer under heating and reduced pressure, and 300 parts by weight of methyl isobutyl ketone was added to the residue to dissolve it. This methyl isobutyl ketone solution was heated to 70°C, 10 parts by weight of 30% aqueous sodium hydroxide solution was added, and the reaction was allowed to proceed for 1 hour. After this, the reaction solution was repeatedly washed with water until the washing solution became neutral. Next, 135 parts by weight of epoxy resin (EP3) was obtained by distilling methyl isobutyl ketone from the oil layer under heating and reduced pressure. The GPC chart of epoxy resin (EP3) is shown in Figure 3. The epoxy equivalent of the epoxy resin (EP3) was 288 g/eq., the softening point was 68°C, and the ICI melt viscosity was 0.30 Pa·s (150°C). In GC analysis, the epoxy compound represented by Formula 2 was below the detection limit (peaks around 21.1 and 22.1 minutes in Figure 4C).

[Examples 4, 5, Comparative Example 1]

The main ingredients are epoxy resin mixture (EP1, EP2) and epoxy resin (EP3), respectively, phenol novolac (abbreviated as PN, hydroxyl equivalent 103 g/eq.) as the curing agent, and triphenylphosphine (abbreviated as TPP) as the curing accelerator. was mixed in the weight ratio shown in the composition in Table 1, kneaded with two rolls, tabletted, and then transfer molded to prepare a resin molded body, and cured under curing conditions of 160°C for 2 hours and further at 180°C for 6 hours.

Physical property values were measured under the following conditions.

ㆍDMA analysis

Maker: TA Instruments

Device: DMAQ800

Measurement Mode: Tensile

Temperature increase rate: 2℃/min.

Measurement temperature range: 25℃ ~ 350℃

Measurement frequency: 10Hz

The temperature at which the value of tanδ reached its maximum was set as Tg.

ㆍ3-point bending test

Manufacturer: A&D Co., Ltd.

Device: RTG-1310

Test speed: 3mm/min

Point-to-point distance: 64mm

ㆍAbsorption rate

A disk-shaped test piece with a diameter of 5 cm The weight increase rate (%) was calculated from these weights.

From the results in Table 1, it was confirmed that the heat resistance of Examples 4, 5, and Comparative Example 1 exceeded 150°C. Additionally, it was confirmed that Examples 4 and 5 had a high elastic modulus and were also excellent in low water absorption properties.

The present invention is particularly useful for applications such as insulating materials for electrical and electronic components (high-reliability semiconductor encapsulation materials, etc.) and laminated boards (printed wiring boards, build-up boards, etc.), various composite materials including FRP, adhesives, paints, etc. , It is useful for laminates with metal foil, insulating materials for build-up boards, flexible board materials, etc.

Claims (5)

An epoxy resin mixture containing an epoxy resin represented by the following formula (1) and an epoxy compound represented by the following formula (2).
[Formula 1]

(In equation (1), n is the number of repetitions and represents a real number from 1 to 20.)
[Formula 2]
The method according to claim 1, wherein when the content of the epoxy resin in which n in the formula (1) is 1 in the gas chromatography analysis is 100 area%, the content of the epoxy compound represented by the formula (2) is 1.0 to 10.0 area%. Epoxy resin mixture. An epoxy resin composition containing the epoxy resin mixture according to claim 1 or 2 and a curing agent. A cured product obtained by curing the epoxy resin composition according to claim 3. A method for producing an epoxy resin mixture according to claim 1 or 2, which is obtained by reacting epichlorohydrin with a phenol resin represented by the following formula (3) and a phenol compound represented by the following formula (4).
[Formula 3]

(In equation (3), n is the number of repetitions and represents a real number from 1 to 20.)
[Formula 4]