JP2010163540A - Epoxy resin composition and cured material of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition capable of obtaining a cured material having high heat resistance and high thermoconductivity. <P>SOLUTION: This cured material obtained by curing the epoxy resin composition containing an epoxy resin expressed by formula (1) (wherein R is H or methyl; and R<SB>1</SB>to R<SB>4</SB>are each independently H, 1-8C hydrocarbon, trifluoromethyl, aryl, or methoxy) and a curing agent has the excellent heat resistance and the high thermoconductivity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  An object of the present invention is to provide an epoxy resin composition containing a high-performance and high-functional epoxy resin having a specific structure, exhibiting liquid crystallinity and high thermal conductivity, and having a low melting point, and a cured product thereof. And

Epoxy resins are resins that have an excellent balance of various properties such as electrical, thermal and mechanical properties and adhesiveness. For this reason, it has been used for a long time in the fields of paints, coatings, adhesives, etc., but recently it has also been used in the fields of electrical and electronic parts manufacturing materials, and its application range is expanding. well known. With such expansion of the field of use, epoxy resins are required to have higher performance and new functions. In particular, materials for manufacturing electrical and electronic parts are required to be cured epoxy resins having high thermal conductivity for the purpose of quickly releasing the heat generated when these parts are in operation. Various new epoxy resins have been actively developed, but no one satisfying the market demand has been obtained yet.
As one of the researches aimed at developing such new high-performance and high-performance epoxy resins, attempts have been made to introduce mesogenic groups into the network structure of cured epoxy resins. The mesogen referred to here is a central atomic group for forming a liquid crystal phase, and is characterized by having a rigid rod-like or planar structure and high alignment.
Patent Documents 1 to 4 describe epoxy compounds into which various mesogenic groups are introduced.

Japanese Patent Laid-Open No. 02-232220 Japanese Patent Laid-Open No. 02-275872 Japanese Patent Laid-Open No. 04-233934 JP-T-08-503728

  However, the epoxy resin having a mesogenic group as described in Patent Documents 1 to 4 has a complicated structure and a manufacturing method, and has a melting point of 250 to 350 ° C. higher than that of a general epoxy resin. There was a problem that molding conditions were very severe. In addition, Patent Documents 1 to 4 do not disclose that these cured epoxy resins have high thermal conductivity.

The present inventors have completed the present invention as a result of intensive studies in order to solve the above problems.
That is, the present invention provides (1) the following formula (1)

(Wherein, R represents a hydrogen atom or a methyl group, R ₁ to R ₄ are each independently hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, a trifluoromethyl group, an aryl group or a methoxy group. And an epoxy resin composition comprising a curing agent,
(2) The epoxy resin composition according to item (1), which contains an inorganic filler,
(3) The epoxy resin composition according to the above item (2) or (3), which contains a curing accelerator;
(4) A cured product obtained by curing the epoxy resin composition according to any one of (1) to (3),
About.

  Although the epoxy resin composition of the present invention contains an epoxy resin represented by the formula (1) having a very high molecular orientation, the melting point is low, and the cured product has excellent toughness and high heat. Shows conductivity. Therefore, it is useful for insulating materials for electrical and electronic parts such as highly reliable semiconductor encapsulating materials, laminated plates such as printed wiring boards and build-up substrates, various composite materials including CFRP, adhesives and paints.

2 is a 1H-NMR spectrum of an epoxy resin represented by formula (1) obtained in Synthesis Example 1. FIG.

  The epoxy resin represented by the formula (1), which is an essential component of the epoxy resin composition of the present invention, is an aldehyde or ketone represented by the following formula (2) and an aminophenol represented by the following formula (3). Kind

(Wherein R and R _{1 to} R ₄ represent the same meaning as in formula (1)), and the following formula (4)

(Wherein R and R _{1 to} R ₄ represent the same meaning as in formula (1)), and can be obtained by a glycidylation reaction in which an epihalohydrin is reacted. .

The hydrocarbon group having 1 to 8 carbon atoms represented by R _{1 to} R ₄ in Formula (1) is a saturated or unsaturated, linear, branched or cyclic hydrocarbon group having 1 to 8 carbon atoms. Specific examples thereof include, for example, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, hexyl group, octyl group, cyclopentyl group, and cyclohexyl. Groups and the like.
Specific examples of the aryl group represented by R _{1 to} R ₄ in Formula (1) include a phenyl group, a tolyl group, and a xylyl group.

The reaction between the aldehyde or ketone represented by the formula (2) and the aminophenol represented by the formula (3) is usually performed in a solvent. The solvent that can be used here is not particularly limited as long as aldehydes or ketones and aminophenols as raw materials are dissolved and do not adversely affect the reaction. For example, aprotic polarities such as alcohols such as methanol, ethanol, propanol, dimethylsulfone, dimethylsulfoxide, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, dioxane, acetonitrile, tetrahydrofuran, diglyme, etc. A solvent is suitable, and these may be mixed and used.
The usage-amount of a solvent is 50-1000 mass% normally with respect to a raw material compound, Preferably it is 100-500 mass%.
The catalyst can be used as necessary, and zinc chloride or the like can be used. The catalyst amount is 0.01 to 5% by mass, preferably 0.05 to 1% by mass, based on the raw material compound. The reaction temperature is -10 to 120 ° C, preferably 25 to 80 ° C. The reaction time is 1 to 12 hours, preferably 2 to 6 hours.
When the solvent used in the reaction is volatile, the solvent can be distilled off after completion of the reaction, and a polyhydric phenol compound can be obtained by washing with water and recrystallization. When the solvent used in the reaction is nonvolatile, a polyhydric phenol compound can be obtained by washing with water and extracting with a solvent.

The epihalohydrins used for the glycidylation reaction of the polyhydric phenol compound represented by the formula (4) include epichlorohydrin, epibromhydrin, epiiodohydrin and the like. From the viewpoint of industrial use, epichlorohydrin is preferable.
In the glycidylation reaction, a solid of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to the mixture of the polyhydric phenol compound and the epihalohydrin as a catalyst, or 0 to 20 to 120 ° C. while adding. Let react for 5-10 hours. As the alkali metal hydroxide, an aqueous solution may be used. In this case, the alkali metal hydroxide is continuously added, and water and epihalohydrin are continuously distilled from the reaction mixture under reduced pressure or normal pressure. After letting out, water may be removed by liquid separation, and only the epihalohydrin may be continuously returned during the reaction mixing.
The preferred use amount of epihalohydrins is 0.5 to 20 moles, more preferably 0.5 to 15 moles, per mole of hydroxyl group of the polyhydric phenol compound. The usage-amount of an alkali metal hydroxide is 0.5-2.0 mol normally with respect to 1 mol of hydroxyl groups in a polyhydric phenol compound, Preferably it is 0.7-1.5 mol.

The reaction solvent is not particularly limited as long as it dissolves the starting polyhydric phenol compound and does not adversely affect the reaction. For example, aprotic polarities such as alcohols such as methanol, ethanol, propanol, dimethylsulfone, dimethylsulfoxide, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, dioxane, acetonitrile, tetrahydrofuran, diglyme, etc. A solvent is suitable, and these may be mixed and used. The usage-amount of a solvent is 50-1000 mass% normally with respect to a polyhydric phenol compound, Preferably it is 100-500 mass%.
In the reaction, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide, trimethylbenzylammonium chloride can be used as a catalyst. The amount of the quaternary ammonium salt used in this case is usually 0.001 to 0.2 mol, preferably 0.05 to 0.1 mol, relative to 1 mol of the hydroxyl group of the polyhydric phenol compound. These catalysts may be used in combination with the above solvents.

  After completion of the reaction, a precipitate containing an epoxy resin represented by the formula (1) (optionally containing an inorganic salt) is filtered off from the reaction mixture, washed with water, and if necessary through a purification step such as recrystallization, to obtain the formula (1 ) Can be obtained. In addition, only inorganic salts are removed from the filtrate from which precipitates have been removed by filtration, washing with water, or a combination of both. When the reaction is carried out again by adding an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, the yield may be further improved. In this case, the usage-amount of an alkali metal hydroxide is 0.01-0.2 mol normally with respect to 1 mol of phenolic hydroxyl groups of the prepared polyhydric phenol compound, Preferably it is 0.05-0.1 mol. The reaction temperature is usually 50 to 120 ° C., and the reaction time is usually 0.5 to 2 hours.

The epoxy resin represented by the formula (1) has very high crystallinity. An amorphous resinous solid can be obtained by supercooling from a molten state, but a crystalline resinous solid can also be obtained by slow cooling. Moreover, it can also be set as a crystallized substance by performing crystallization. As the crystallization method, crystallization by temperature difference, solubility difference, etc. can be applied. Specifically, for example, heating and dissolving in the above reaction solvent and cooling, or adding water or higher alcohols which are poor solvents, etc. Crystals can be deposited by a technique, and the crystals can be filtered and dried to obtain a crystalline epoxy resin.
In the DSC (differential scanning calorimetry) measurement of the epoxy resin represented by the formula (1) thus obtained, an endothermic peak resulting from the collapse of the crystal structure near the melting point, which is characteristic of liquid crystallinity, and thereafter Two endothermic peaks resulting from the transition of the alignment maintained in the liquid crystal state to an isotropic state are observed.

Next, the epoxy resin composition of the present invention will be described.
The epoxy resin composition of the present invention contains an epoxy resin represented by the formula (1) and a curing agent. In the epoxy resin composition of the present invention, the epoxy resin represented by the formula (1) can be used alone or in combination with other epoxy resins. When used in combination, the proportion of the epoxy resin represented by formula (1) in the total epoxy resin is preferably 30% by mass or more, and particularly preferably 40% by mass or more.
Other epoxy resins that can be used in combination with the epoxy resin represented by the formula (1) include bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, terpene diphenol, 4,4-biphenol, 2,2-biphenol, 3 , 3,5,5-tetramethyl- [1,1-biphenyl] -4,4-diol, hydroquinone, resorcin, naphthalenediol, tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) and formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, OH Loxybenzaldehyde, p-hydroxyacetophenone, o-hydroxyacetophenone, dicyclopentadiene, furfural, 4,4-bis (chloromethyl) -1,1-biphenyl, 4,4-bis (methoxymethyl) -1,1-biphenyl, Derived from polycondensates with 1,4-bis (chloromethyl) benzene, 1,4-bis (methoxymethyl) benzene, etc. and their modified products, halogenated bisphenols such as tetrabromobisphenol A, and alcohols. Solid or liquid epoxy resins such as glycidyl etherified products, alicyclic epoxy resins, glycidyl amine epoxy resins, glycidyl ester epoxy resins and the like can be mentioned, but are not limited thereto. These may be used alone or in combination of two or more.

Examples of the curing agent contained in the epoxy resin composition of the present invention include amine compounds, acid anhydride compounds, amide compounds, and phenol compounds. Specific examples of the curing agent that can be used include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, polyamide resin synthesized from linolenic acid and ethylenediamine, phthalic anhydride, trimellitic anhydride Acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, polyvalent represented by the above formula (4) Phenol compound, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, terpene diphenol, 4,4-biphenol, 2,2-biphenol, 3,3,5,5-tetramethyl- [ , 1-biphenyl] -4,4-diol, hydroquinone, resorcin, naphthalenediol, tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenols (phenol Alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, catechol, resorcin, hydroquinone, dihydroxynaphthalene, etc.) and formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, o-hydroxybenzaldehyde, p-hydroxyacetophenone, o-hydroxyacetophenone, dicyclo Pentadiene, furfural, 4,4-bis (chloromethyl) -1,1-biphenyl, 4,4-bis (methoxymethyl) -1,1-biphenyl, 1,4- Scan (chloromethyl) benzene, 1,4-bis polycondensate of (methoxymethyl) benzene and modified products thereof, halogenated bisphenols such as tetrabromobisphenol A, imidazole, BF ₃ - amine complex, guanidine derivatives However, it is not limited to these. These may be used alone or in combination of two or more.
In the epoxy resin composition of the present invention, the amount of the curing agent used is preferably 0.5 to 2.0 equivalents, particularly preferably 0.6 to 1.5 equivalents, based on 1 equivalent of the epoxy group of the epoxy resin. When it is less than 0.5 equivalent to 1 equivalent of epoxy group, or when it exceeds 2.0 equivalent, curing may be incomplete and good cured properties may not be obtained.

Moreover, when using the said hardening | curing agent, a hardening accelerator may be used together. Examples of the curing accelerator that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, triethylenediamine, Triethanolamine, tertiary amines such as 1,8-diazabicyclo (5,4,0) undecene-7, organic phosphines such as triphenylphosphine, diphenylphosphine and tributylphosphine, metal compounds such as tin octylate, Tetraphenylphosphonium / tetraphenylborate, tetrasubstituted phosphonium / tetrasubstituted borate such as tetraphenylphosphonium / ethyltriphenylborate, 2-ethyl-4-methylimidazole / tetraphenylborate, N-methylmol Such as tetraphenyl boron salts such as phosphorus-tetraphenylborate and the like.
When the curing accelerator is used, 0.01 to 15 parts by mass is used as necessary with respect to 100 parts by mass of the epoxy resin.

  Furthermore, an inorganic filler, a silane coupling agent, a mold release agent, various compounding agents such as a pigment, and various thermosetting resins can be added to the epoxy resin composition of the present invention as necessary. Examples of inorganic fillers include crystalline silica, fused silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, zirconia, fosterite, steatite, spinel, titania, talc, and the like. However, the present invention is not limited to these. These may be used alone or in combination of two or more. An inorganic filler is normally used in the ratio which occupies 10-95 mass% in an epoxy resin composition.

  The epoxy resin composition of the present invention can be obtained by uniformly mixing the above components. The epoxy resin composition of the present invention can be easily made into a cured product by a method similar to a conventionally known method. For example, until the epoxy resin of the present invention and a curing agent, and if necessary, a curing accelerator, an inorganic filler, a compounding agent and various thermosetting resins are made uniform using an extruder, a kneader, a roll or the like as necessary The epoxy resin composition of the present invention obtained by thorough mixing is molded by a melt casting method, a transfer molding method, an injection molding method, a compression molding method, or the like, and further heated at 80 to 200 ° C. for 2 to 10 hours. Thus, a cured product of the epoxy resin composition of the present invention can be obtained.

  Moreover, the epoxy resin composition of the present invention may optionally contain a solvent. By hot press molding a prepreg obtained by impregnating a base material such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber or paper with an epoxy resin composition containing a solvent (epoxy resin varnish) and drying by heating. The cured product of the epoxy resin composition of the present invention can be used. When the solvent is included, the content of the solvent is usually about 10 to 70% by mass, preferably about 15 to 70% by mass with respect to the total amount of the epoxy resin composition of the present invention and the solvent. Moreover, the epoxy resin composition containing this solvent can be used also as the following varnish. Examples of the solvent include amide solvents such as γ-butyrolactone, N-methylpyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide, N, N-dimethylimidazolidinone, tetra Sulfones such as methylene sulfone, ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether monoacetate, propylene glycol monobutyl ether, preferably lower alkylene glycol mono or di-lower alkyl ether, methyl ethyl ketone, Ketone solvents such as methyl isobutyl ketone, preferably di-lower alkyl ketones in which two alkyl groups may be the same or different; Emissions, and aromatic solvents such as xylene. These solvents may be used alone or in combination of two or more. Moreover, a sheet-like epoxy resin composition can be obtained by apply | coating the said varnish on a peeling film, removing a solvent under heating, and performing B-staging. This sheet-like epoxy resin composition can be used as an interlayer insulating layer in a multilayer substrate or the like.

The cured product of the epoxy resin composition of the present invention can be used for various applications in which a thermosetting resin such as an epoxy resin is used. Specific applications include, for example, adhesives, paints, coating agents, molding materials (including sheets, films, RP, etc.), insulating materials (including printed circuit boards, wire coatings, etc.), sealants, etc. Examples include additives to resins and the like.
Examples of the adhesive include civil engineering, architectural, automotive, general office, and medical adhesives, and electronic material adhesives. Among these, adhesives for electronic materials include interlayer adhesives for multilayer substrates such as build-up substrates, die bonding agents, semiconductor adhesives such as underfills, BGA reinforcing underfills, anisotropic conductive films ( ACF) and an adhesive for mounting such as anisotropic conductive paste (ACP).
Sealing agents include capacitors, transistors, diodes, light emitting diodes, potting, dipping, transfer mold sealing for ICs, LSIs, potting sealings for ICs, LSIs such as COB, COF, TAB, flip chips, etc. Underfill, and sealing (including reinforcing underfill) when mounting IC packages such as QFP, BGA, and CSP.

Hereinafter, the present invention will be described in more detail with reference to examples. The equipment and analysis conditions used for the analysis are as follows.
DSC (differential scanning calorie)
Measuring instrument: DSC6200 (manufactured by Seiko Electronics Co., Ltd.)
Temperature increase rate: 10 ° C / minn
Pan: Al pan NMR (nuclear magnetic resonance)
Measuring instrument: Gemini 300 (manufactured by Varian)
Solvent used: DMSO-d6
Measurement temperature: 25 ° C
Thermal conductivity measuring device: UNITHERM MODEL 2022 (THERMAL CONDUCTIVITY INSTRUMENT made)
Measurement temperature: 30 ° C
Glass transition point measuring instrument: DMA2980 (TAinstruments)
Temperature increase rate: 2 ° C / min

Synthesis Example 1 (Synthesis of a polyhydric phenol compound in which R and R _{1 to} R ₄ in Formula (4) are all hydrogen atoms)
A flask equipped with a stirrer, a reflux condenser, and a stirrer was charged with 122.12 g of p-hydroxybenzaldehyde, 113.6 g of p-aminophenol, 400 g of ethanol, and 0.2 g of zinc chloride, and the temperature was raised to 70 ° C. while stirring. And dissolved. After reacting at 70 ° C. for 4 hours, it was cooled to room temperature. After completion of the reaction, the reaction solution was poured into 3 L of water, the precipitated crystals were filtered, and the obtained crystals were vacuum dried to obtain 205 g of a polyhydric phenol compound (a).

Synthesis Example 2 (Synthesis of epoxy resin in which R and R _{1 to} R ₄ in formula (1) are all hydrogen atoms)
A flask equipped with a stirrer, a reflux condenser, and a stirrer was charged with 111.8 g of the polyhydric phenol compound (a) obtained in Synthesis Example 1, 400 g of epichlorohydrin, 200 g of dimethyl sulfoxide, and 10.2 g of water. The solution was heated up to ° C and dissolved. To this was added 22.6 g of flaky sodium hydroxide (purity 99%) over 90 minutes, followed by reaction at 60 ° C. for 3 hours, and then cooling to room temperature. After completion of the reaction, the reaction solution was poured into 3 L of water, the precipitated crystals were filtered, and the crystals obtained by repeated washing with water were vacuum-dried to obtain 98 g of epoxy resin (A).
As a result of DSC measurement of the epoxy resin (A), endothermic peaks were observed at 194 ° C. and 228 ° C. Moreover, the 1H-NMR spectrum of the obtained epoxy resin (A) is shown in FIG.

Example 1 (Measurement of thermal conductivity and glass transition point of cured product of epoxy resin composition of the present invention)
10 g of the epoxy resin (A) obtained in Synthesis Example 2 and 1.8 g of diaminodiphenylmethane as a curing agent were mixed and cured at 175 ° C. to obtain a cured product. The glass transition point of the cured product was 225 ° C., and the thermal conductivity at 30 ° C. was 0.33 W / (m · K).

Comparative Example 1 (Measurement of thermal conductivity and glass transition point of cured product of comparative epoxy resin composition)
180 g of biphenyl type epoxy resin (trade name: YL6121H, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 175 g / eq.) Containing an epoxy resin represented by the following formulas (5) and (6) in equimolar amounts, Diaminodiphenylmethane 51 g was mixed and cured at 175 ° C. to obtain a cured product. The glass transition point of this cured product was 192 ° C., and the thermal conductivity at 30 ° C. was 0.31 W / (m · K).

  The cured product of the epoxy resin composition of the present invention exhibits high heat resistance and low melting point even though the epoxy resin is bifunctional. In addition, it exhibits a much higher thermal conductivity than a conventional cured epoxy resin. Therefore, it is extremely useful when used for materials for electrical / electronic parts production, various composite materials including CFRP, adhesives, paints and the like.

Claims (4)

Following formula (1)

(Wherein, R represents a hydrogen atom or a methyl group, R ₁ to R ₄ are each independently hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, a trifluoromethyl group, an aryl group or a methoxy group. The epoxy resin composition formed by containing an epoxy resin represented by (1) and a curing agent. The epoxy resin composition according to claim 1 containing an inorganic filler. The epoxy resin composition of Claim 1 or 2 containing a hardening accelerator. Hardened | cured material formed by hardening | curing the epoxy resin composition of any one of Claims 1-3.

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