JP2019038941A - Thermosetting epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting epoxy resin composition which provides a cured product having good foam removal, rapid curing at a low temperature, and excellent crack resistance. SOLUTION: (A) a liquid epoxy resin which is liquid at 25 ° C., (B) a polyamine-based curing agent which is solid at 25 ° C. and has a melting point of 50 to 120 ° C., (C) a silicone-modified epoxy resin, and ( D) Provided is a thermocurable epoxy resin composition containing an inorganic filler and the component (C) is a hydrosilylation reaction addition of an epoxy resin having a carbon-carbon double bond and a silicone resin having a hydrosilyl group. do. [Selection diagram] None

Description

  The present invention relates to a thermosetting epoxy resin composition.

  Thermosetting silicone has often been used as a potting material for sealing a semiconductor substrate, but in recent years, a highly reliable epoxy resin has been used. However, it is usually necessary to react an epoxy resin at a high temperature of 150 ° C. or higher, and production in a lower temperature environment is required. Therefore, as a required characteristic of the thermosetting epoxy resin used for these semiconductor substrate sealing members, it is required to cure rapidly at a low temperature.

  An one-component low-temperature curable epoxy resin composition using an addition reaction product obtained by reacting an amine compound and a polyglycidyl compound and a latent curing agent containing a phenol resin is disclosed (Patent Document 1). However, since the resin composition of the patent contains a solid curing agent, the thixo ratio and viscosity are high, and there is a problem that foaming is poor for potting applications. Further, the crack resistance is poor, and cracks are likely to occur in the thermal cycle test.

  In addition, a one-part epoxy resin composition using a polythiol compound having two or more thiol groups in the molecule as a curing agent is disclosed (Patent Document 2). However, the thiol-based curing agent has a strong odor and can be inhibited from being used because it may inhibit the curing of other thermosetting resins.

  In addition, a one-part epoxy resin composition using a silicone-modified epoxy resin and an amine curing agent is disclosed (Patent Document 3). However, since the resin composition disclosed in Patent Document 3 uses an aromatic amine or a liquid aliphatic amine as a curing agent, it is necessary to react at a high temperature of 150 ° C. or higher, or a curing reaction occurs at room temperature. There are problems such as rapid progress.

  As described above, it is difficult to say that development of an epoxy resin composition that provides a cured product having excellent crack resistance, good foaming, and rapidly cures at a low temperature has been sufficiently advanced. Development of an epoxy resin having performance has been demanded.

International Publication WO2012 / 020572 International Publication No. WO2005 / 070991 JP 2007-308678 A

  It is an object of the present invention to provide a thermosetting epoxy resin composition that provides a cured product having good storage stability and foaming resistance, rapidly curing at a low temperature, and excellent in crack resistance.

  As a result of intensive studies to achieve the above object, the present inventors have found that a thermosetting epoxy resin composition containing a polyamine-based curing agent and a silicone-modified epoxy resin that is solid at room temperature has good foaming and quickly. The present invention was completed by finding that it was cured at low temperature and that the cured product was excellent in crack resistance.

That is, this invention provides the following thermosetting epoxy resin composition in order to solve the said subject.
<1>
(A) a liquid epoxy resin that is liquid at 25 ° C.,
(B) a polyamine curing agent that is solid at 25 ° C. and has a melting point of 50 to 120 ° C.,
(C) a silicone-modified epoxy resin, and (D) an inorganic filler,
The thermosetting epoxy resin composition, wherein the component (C) is a hydrosilylation reaction adduct of an epoxy resin having a carbon-carbon double bond and a silicone resin having a hydrosilyl group.

<2>
The thermosetting epoxy resin composition according to <1>, wherein the reaction rate after heating at 90 ° C. for 1 hour calculated from the DSC exothermic peak area is 90% or more.

（上記構造式（１）において、Ｒ^１はエポキシ基を有する炭化水素基であり、同じでも異なっていてもよい。Ｒ^２はメチル基または水素原子であり、同じでも異なっていてもよい。）

（上記構造式（２）において、Ｒ^１はエポキシ基を有する炭化水素基であり、同じでも異なっていてもよい。Ｘは水素原子又は臭素原子であり、同じでも異なっていてもよい。ｎは０以上の整数である。） <3>
The thermosetting epoxy resin composition according to <1> or <2>, wherein the epoxy resin having a carbon-carbon double bond is a compound represented by the following structural formula (1) or (2).

(In the structural formula (1), R ¹ is a hydrocarbon group having an epoxy group and may be the same or different. R ² is a methyl group or a hydrogen atom, and may be the same or different.)

(In the structural formula (2), R ¹ is a hydrocarbon group having an epoxy group, and may be the same or different. X is a hydrogen atom or a bromine atom, and may be the same or different. (It is an integer of 0 or more.)

（上記構造式（３）において、Ｒはハロゲン原子、炭素数１〜６の非置換もしくは置換の１価炭化水素基、又はアルコキシ基であり、同じでも異なっていてもよい。ｘは０〜４の整数である。）

（上記構造式（４）において、Ｒはハロゲン原子、炭素数１〜６の非置換もしくは置換の１価炭化水素基、又はアルコキシ基であり、同じでも異なっていてもよい。ｙ、ｚはそれぞれ０〜４の整数である。Ａは単結合、エーテル基、チオエーテル基、ＳＯ_２基、又は炭素数１〜６の非置換もしくは置換の２価炭化水素基である。） <4>
The component (A) is one or more liquid epoxy resins selected from glycidylamine type liquid epoxy resins and bisphenol type liquid epoxy resins represented by the following structural formula (3) or (4) < The thermosetting epoxy resin composition according to any one of 1> to <3>.

(In the structural formula (3), R is a halogen atom, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, or an alkoxy group, and may be the same or different. X is 0 to 4 Is an integer.)

(In the structural formula (4), R is a halogen atom, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, or an alkoxy group, and may be the same or different. It is an integer of 0 to 4. A is a single bond, an ether group, a thioether group, an SO ₂ group, or an unsubstituted or substituted divalent hydrocarbon group having 1 to 6 carbon atoms.

The thermosetting epoxy resin composition of the present invention provides an epoxy resin composition that is excellent in storage stability and foam prevention and that is rapidly cured at a low temperature. Moreover, the cured product of the thermosetting epoxy resin composition is excellent in crack resistance. In the present specification, “rapidly cure at low temperature” means a curing reaction of a thermosetting epoxy resin composition containing a predetermined component that is heated at 60 ° C. to 130 ° C. for 0.5 hours to 10 hours. It means that the reaction rate when performing is 90% or more. The reaction rate of the thermosetting epoxy resin composition was calculated based on the measured value of the thermosetting epoxy resin composition by differential scanning calorimetry (DSC). The area of the region defined by the DSC curve of the thermosetting epoxy resin composition represents the calorific value of the thermosetting epoxy resin composition, and the area value decreases as the curing proceeds. Therefore, in the present specification, the area of the region defined by the DSC curve of the thermosetting epoxy resin composition is defined as “DSC peak area”, and after the curing reaction under the DSC peak area before curing and the above reaction conditions. The ratio with the DSC peak area was defined as the reaction rate. The reaction rate of the thermosetting epoxy resin composition was calculated by the following formula.
Reaction rate (%) = {(DSC peak area value before curing) − (DSC peak area value after curing)} / (DSC peak area value before curing) × 100

[Thermosetting epoxy resin composition]
Hereinafter, the thermosetting epoxy resin composition of the present invention will be specifically described.

<(A) Liquid epoxy resin that is liquid at 25 ° C.>
As the liquid epoxy resin that is liquid at 25 ° C. used as the component (A) in the present invention, a known epoxy resin can be used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin , Alicyclic epoxy resin having ester skeleton, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolak type Epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having butadiene structure, alicyclic epoxy resin, heterocyclic epoxy Butter, spiro ring-containing epoxy resins, cyclohexanedimethanol type epoxy resins, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenyl ethane epoxy resin and the like.

  From the viewpoint of heat resistance and adhesiveness of the cured product and fluidity of the composition, it is preferable to use a glycidylamine type liquid epoxy resin or a bisphenol type liquid epoxy resin. Among them, it is preferable to use a glycidylamine type liquid epoxy resin represented by the following structural formula (3) or (4).

  In the structural formula (3), R is a halogen atom, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, or an alkoxy group, which may be the same or different. x is an integer of 0-4.

In the structural formula (4), R is a halogen atom, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, or an alkoxy group, which may be the same or different. y and z are integers of 0 to 4, respectively. A is a single bond, an ether group, a thioether group, an SO ₂ group, or an unsubstituted or substituted divalent hydrocarbon group having 1 to 6 carbon atoms.

Moreover, you may use what melt | dissolved the solid epoxy resin in the liquid epoxy resin demonstrated above as a liquid epoxy resin of (A) component. Solid epoxy resins include naphthalene type tetrafunctional epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, Anthracene type epoxy resin, bisphenol A type epoxy resin, tetraphenylethane type epoxy resin, alicyclic epoxy resin and the like can be mentioned. The liquid epoxy resin of the component (A) of the present invention may be used alone or in combination of two or more.

  In the thermosetting epoxy resin composition of the present invention, the content of the component (A) is preferably 5% by mass or more and 90% by mass or less, and more preferably 10% by mass or more and 60% by mass or less.

<(B) Polyamine-based curing agent that is solid at 25 ° C. and has a melting point of 50 to 120 ° C.>
The polyamine curing agent that is solid at 25 ° C., which is the component (B) of the present invention, and has a melting point of 50 to 120 ° C. acts as a curing agent for the component (A) and reacts with the component (A). A crosslinked structure is formed, and the liquid epoxy resin as component (A) is cured. (B) Melting | fusing point of the polyamine type hardening | curing agent of a component is 50-120 degreeC, and 50-100 degreeC is preferable. In the present specification, the melting point refers to a value measured by the method described in JIS K 0064: 1992.

  Since the polyamine curing agent (B) is solid at 25 ° C., it has good storage stability and can be dissolved by heating and cured at a low temperature. However, the polyamine type curing agent used in the present invention, which is solid at 25 ° C. of the component (B) and has a melting point of 50 to 120 ° C., usually has an aromatic amine (fragrance which requires a curing temperature of 150 ° C. or higher. In which one or more hydrogen atoms of a group compound are substituted with an amine).

  The component (B) used in the present invention is a polyamine curing agent that is solid at 25 ° C. and has a melting point of 50 to 120 ° C., preferably 50 to 100 ° C., and the melting point of the polyamine curing agent is 50 ° C. If it is lower, the potential may be impaired, and if the melting point is higher than 120 ° C., the low-temperature curability may be impaired. In the present specification, “latency of curing agent” refers to the ability of a composition in which a curing agent is blended with an epoxy resin to be stably stored at room temperature and to rapidly cure the composition by heat.

  As the polyamine curing agent (B), those produced by a known method can be used. The polyamine-based curing agent is a polyamine modified with a compound in which a group having reactivity with an amine such as an epoxy group is bonded in order to control the curability to the thermosetting epoxy resin composition and the melting point of the component (B). Including. The modified polyamine-based curing agent is obtained, for example, by reacting an epoxy resin (such as a bisphenol A type epoxy resin) and a polyamine compound (such as an alkylenediamine compound such as ethylenediamine, a polyalkylpolyamine compound, or an alicyclic polyamine compound). Examples include modified polyamine compounds having a polymer structure. For a more specific example of the polyamine-based cured product, Japanese Patent No. 5876414 can be referred to. In addition, as the polyamine curing agent, commercially available products (for example, “EH-5015S”, “EH-5030S”, “EH-4357S” (hereinafter, trade names manufactured by ADEKA) and the like) can also be used. In addition, in order to control the reactivity and fluidity of the component (B), an inorganic material such as silica supported on polyamine may be used. One of these polyamine curing agents may be used alone, or two or more thereof may be used.

  The average particle size of the polyamine curing agent (B) is preferably 20 μm or less, and more preferably 10 μm or less from the viewpoint of entry into the fine region of the composition. If the average particle size is larger than 20 μm, the penetration of the composition into the fine region may be impaired. In the present specification, the average particle diameter means an accumulated mass average diameter (d50) measured by a laser light diffraction method.

  The blending amount of the polyamine curing agent (B) is such that the number of moles of reactive groups (amino groups) in the component (B) is 1 mol of epoxy groups contained in the components (A) and (C). An amount of 0.4 to 2.0 mol is preferable, and an amount of 0.6 to 1.2 mol is more preferable. If the number of moles is less than 0.4 moles, the glass transition temperature (Tg) may be lowered. On the other hand, if the number of moles exceeds 2.0, the curing may be poor.

<(C) Silicone-modified epoxy resin>
The silicone-modified epoxy resin that is the component (C) of the present invention imparts flexibility to the thermosetting epoxy resin composition and includes a silicone skeleton in the structure of the thermosetting epoxy resin composition. As a result, the present invention provides a cured product with good foaming and good crack resistance.

  The component (C) used in the present invention is a silicone-modified epoxy resin obtained by modifying an epoxy resin with silicone. Among these, from the simplicity of the reaction, those obtained by hydrosilylation reaction of an epoxy resin containing a carbon-carbon double bond and a silicone resin containing a hydrosilyl group are used. In this hydrosilylation reaction, the molar ratio of hydrosilyl group to alkenyl group is preferably such that the number of moles of hydrosilyl group is 0.0001 to 2.0, more preferably 0.01 to 0, per mole of alkenyl group. The amount is 2 mol. If the number of moles is less than 0.0001 mole, crack resistance may be insufficient. On the other hand, if it exceeds 2.0, a large amount of unreacted hydrosilyl groups may remain.

  As an epoxy resin containing a carbon-carbon double bond, an epoxy resin having a vinyl group, an allyl group, or the like can be exemplified. Specifically, 1,2-epoxy-4-vinylcyclohexane, diallyl monoglycidyl isocyanurate, monoallyl diglycidyl isocyanurate, represented by the following structural formulas (1), (2), (5), (6) And an epoxy resin having a carbon-carbon double bond. Among these, from the viewpoint of the fluidity of the composition and the heat resistance of the cured product, it is preferable to use an epoxy resin represented by the structural formulas (1) and (2).

In the structural formula (1), R ¹ is a hydrocarbon group having an epoxy group, and may be the same or different. R ² is a methyl group or a hydrogen atom, and may be the same or different.

In the structural formula (2), R ¹ is a hydrocarbon group having an epoxy group, and may be the same or different. X is a hydrogen atom or a bromine atom, and may be the same or different. n is an integer of 0 or more, preferably 0 to 50, more preferably 1 to 20.

In the structural formula (5), R ¹ is a hydrocarbon group having an epoxy group and may be the same or different. X is a hydrogen atom or a bromine atom, and may be the same or different. n and m are 0 or more, preferably 0 to 100, more preferably an integer of 1 to 50.

In the structural formula (6), R ¹ is a hydrocarbon group having an epoxy group and may be the same or different. X is a hydrogen atom or a bromine atom, and may be the same or different. n is an integer of 0 or more, preferably 0 to 100, more preferably 1 to 50.

In the structural formulas (1), (2), (5) and (6), the hydrocarbon group having an epoxy group represented by R ¹ is preferably an oxirane group represented by the following structural formula (7).

The silicone resin to be reacted with the epoxy resin having a carbon-carbon double bond is preferably represented by the average composition formula (8).
(R ¹ ) _a (R ² ) _b SiO _{(4-ab) / 2} (8)

In the above average composition formula (8), R ¹ is a hydrogen atom, an organic group containing an amino group, an epoxy group, a hydroxy group or a carboxy group, or an alkoxy having 1 to 10 carbon atoms, preferably an alkoxy having 1 to 5 carbon atoms. As the alkoxy group, a methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, tert-butoxy group, hexyloxy group, octyloxy group and the like are preferable. The silicone resin has at least one hydrogen atom as R ¹ . R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, a hydroxy group, an alkoxy group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, or , An alkenyloxy group having 1 to 5 carbon atoms, preferably 1 to 10 carbon atoms, a and b satisfying 0.001 ≦ a ≦ 1, 1 ≦ b ≦ 3, and 1 ≦ a + b ≦ 4. It is. The number of silicon atoms in one molecule is 1 to 1,000.

Examples of the substituted or unsubstituted monovalent hydrocarbon group represented by R ² in the above average composition formula (8) include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group, and an octyl group. Alkyl groups such as phenyl groups; aryl groups such as phenyl groups and tolyl groups; aralkyl groups such as benzyl groups and phenylethyl groups; and some or all of the hydrogen atoms of these groups are halogen atoms such as fluorine atoms and chlorine atoms And substituted monovalent hydrocarbon groups substituted with the above. Examples of alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, hexyloxy, octyloxy, alkenyloxy, vinyloxy, An allyloxy group etc. are mentioned.

  Among the silicone resins represented by the formula (8), a silicone resin represented by the following structural formula (9) is preferable from the viewpoint of fluidity and reactivity.

In the structural formula (9), R ² is a substituted or unsubstituted monovalent hydrocarbon group, a hydroxy group, an alkoxy group, or an alkenyloxy group, preferably a substituted or unsubstituted monovalent hydrocarbon group. More preferably, they are a methyl group and a phenyl group. p is an integer of 0 to 1,000, preferably 3 to 400, and q is an integer of 0 to 20, preferably 0 to 5.

In the formula (9), examples of the substituted or unsubstituted monovalent hydrocarbon group represented by R ² include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group, and an octyl group. Alkyl groups; aryl groups such as phenyl and tolyl groups; aralkyl groups such as benzyl and phenylethyl groups, and some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine and chlorine atoms And substituted monovalent hydrocarbon groups. Examples of alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, hexyloxy, octyloxy, alkenyloxy, vinyloxy, An allyloxy group etc. are mentioned.

  The blending amount of the silicone-modified epoxy resin as the component (C) is preferably 1 to 40 parts by mass with respect to a total of 100 parts by mass of the component (A), the component (B) and the component (C), and 3 to 20 It is more preferable to set it as a mass part. If it is less than 1 part by mass, the resulting cured product may have insufficient crack resistance. On the other hand, when the amount is more than 40 parts by mass, the heat resistance of the cured product may be lowered or the thermosetting epoxy resin composition may be thickened and handling may be deteriorated.

<(D) Inorganic filler>
As the inorganic filler that is the component (D) to be blended with the thermosetting epoxy resin composition of the present invention, those that are usually blended with the epoxy resin composition can be used. Examples of the inorganic filler include silicon-based fillers such as silica-based fine powders such as fused silica and crystalline silica and hollow silica; aluminum-based fillers such as alumina, aluminum hydroxide, and aluminum nitride; silicon nitride, boron nitride Metal nitride fillers such as; fiber fillers such as glass fiber and wollastonite; antimony trioxide, silver filler, copper filler, aluminum filler and the like. Among these, silicon-based fillers are preferable, and it is particularly preferable to use fused silica. These inorganic fillers may be used alone or in combination of two or more. The average particle size and shape of the filler are not particularly limited, but it is preferable to use a spherical one from the viewpoint of fluidity.

  In order to increase the bond strength between the inorganic filler and the mixture of the liquid epoxy resin of component (A), the polyamine curing agent of component (B), and the silicone-modified epoxy resin of component (C), the inorganic filler A surface treated in advance with a silane coupling agent (adhesion aid) may be used. Examples of the silane coupling agent include alkoxysilanes containing monovalent hydrocarbon groups substituted with functional groups such as alkenyl groups, epoxy groups, (meth) acryloxy groups, amino groups, mercapto groups, ureido groups, and / or Or these partial hydrolysis-condensation products etc. are mentioned.

  Specifically, epoxy-functional alkoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N- β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, amino-functional alkoxysilanes such as N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, etc. It is preferable to use mercapto-functional alkoxysilane. These coupling agents may be used alone or in combination of two or more.

  In addition, about the compounding quantity and surface treatment method of the coupling agent used for surface treatment, if it is in the range which can obtain the effect of this invention, it will not restrict | limit in particular. The blending amount of the inorganic filler of component (D) is preferably 10 to 1,000 parts by mass with respect to 100 parts by mass in total of the components (A), (B) and (C). More preferably, it is 150 mass parts.

If necessary, the following components may be added to the thermosetting epoxy resin composition of the present invention.
<(E) Other ingredients>
Various additives can be further blended in the thermosetting epoxy resin composition of the present invention as necessary. For example, various diluents, polysiloxanes, low stress agents, mold release agents, halogen trap agents, adhesion aids, antifoaming agents, curing accelerators, etc. are added for the purpose of improving the properties of thermosetting epoxy resin compositions. An agent can be blended.

Adhesive aids, antifoaming agents, curing accelerators, and other various additives are blended in suitable amounts within a range that does not impair the effects of the present invention. When adding an adhesion assistant, as an example of the blending amount, when the total blending amount of 100 parts by weight of the component (A), the component (B) and the component (C) is 0.5 to 5 parts by weight And may be 1 to 3 parts by mass. As described above, as an adhesion assistant, an alkoxysilane containing a monovalent hydrocarbon group substituted with a functional group such as an alkenyl group, an epoxy group, a (meth) acryloxy group, an amino group, a mercapto group, or a ureido group. And / or a partially hydrolyzed condensate thereof. More specifically, epoxy functional alkoxysilane such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N -Β (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, amino-functional alkoxysilanes such as N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, etc. It is preferable to use a mercapto-functional alkoxysilane.
Examples of the antifoaming agent include dimethylpolysiloxane, polyoxyalkylene alkyl ether, synthetic resin particles, silica, or a mixture of two or more thereof.

  As a hardening accelerator, a well-known thing can be used as a hardening accelerator of an epoxy resin composition, Although it does not specifically limit, For example, basic organic compounds, such as organic phosphorus, an imidazole, and a tertiary amine, are mentioned.

  Examples of organic phosphorus include triphenylphosphine, tributylphosphine, tri (p-toluyl) phosphine, tri (p-methoxyphenyl) phosphine, tri (p-ethoxyphenyl) phosphine, triphenylphosphine / triphenylborate derivatives, tetra Examples thereof include phenylphosphine and tetraphenylborate derivatives.

  Examples of imidazole include 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxy Examples include methylimidazole and 2-phenyl-4,5-dihydroxymethylimidazole.

  Examples of the tertiary amine include triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, 1,8-diazabicyclo [5,4,0] undecene-7, and the like.

  Among these, imidazole derivatives are preferable, and 2-ethyl-4-methylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole are more preferable from the viewpoint of curability.

  It is preferable that the addition amount of a hardening accelerator is 0.01-10 mass parts with respect to a total of 100 mass parts of (A) component, (B) component, and (C) component, 0.05-5 More preferably, it is part by mass. When the addition amount of the curing accelerator is less than 0.05 parts by mass, the curing acceleration effect of the thermosetting epoxy resin composition may be insufficient, and when it is more than 5 parts by mass, the thermosetting epoxy is used. There is a risk of impairing the storage stability of the resin composition.

[Method for producing thermosetting epoxy resin composition]
The manufacturing method in particular of the thermosetting epoxy resin composition of this invention is not restrict | limited, It selects arbitrarily according to a component and the objective. As an example of the manufacturing method of this thermosetting epoxy resin composition, the mixing process which mixes (A) component, (B) component, (C) component, and (D) component using a mixer, a roll, etc. is included. A manufacturing method is mentioned. In the mixing step, not only the components (A) to (D) but also the components exemplified in the component (E) may be blended as necessary, and the conditions such as the mixing order, time, temperature, and atmospheric pressure are determined. Can be controlled. Therefore, the components (A) to (D) and other components may be mixed at a time or may be mixed stepwise. The component (B) may be added and mixed to a mixture in which components other than the component (B), that is, the component (A), the component (C), the component (D), and other components are mixed in advance. In the latter case, a step of making the (B) component easy to uniformly disperse in the mixture by, for example, pulverizing a solid polyamine-based curing agent at 25 ° C. of the (B) component in advance may be added.

  The thermosetting epoxy resin composition described above has good foaming and rapidly cures at a low temperature. Moreover, the cured product of the thermosetting epoxy resin composition is excellent in crack resistance.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.

[Synthesis Example 1] Synthesis of silicone-modified epoxy resin c-1 Into a flask equipped with a stirring blade, a dropping funnel, a thermometer, an ester adapter and a reflux tube, 150 g of epoxy resin represented by the following formula (10) and 300 g of toluene are placed. After azeotropic dehydration at 130 ° C. for 2 hours, the mixture was cooled to 100 ° C., 1 g of a catalyst (CAT-PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise, and immediately, an organohydrogen represented by the following formula (11) A mixture of 63 g of polysiloxane (mole number of hydrosilyl group is 0.03 mol with respect to 1 mol of alkenyl group) and 126 g of toluene was dropped over 30 minutes, and the mixture was aged at 100 ° C. for 6 hours. Toluene was removed from the obtained reaction mixture under reduced pressure to obtain a silicone-modified epoxy resin c-1 having a structure represented by the following formula (12).

[Synthesis Example 2] Synthesis of silicone-modified epoxy resin c-2 Into a flask equipped with a stirring blade, a dropping funnel, a thermometer, an ester adapter and a reflux tube, 150 g of epoxy resin represented by the following formula (13) and 300 g of toluene are placed. After azeotropic dehydration at 130 ° C. for 2 hours, the mixture was cooled to 100 ° C., 1 g of a catalyst (CAT-PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise, and immediately the organohydrogen represented by the above formula (11) A mixture of 68 g of polysiloxane (the number of moles of hydrosilyl group is 0.03 mol with respect to 1 mol of alkenyl group) and 136 g of toluene was dropped over 30 minutes and aged at 100 ° C. for 6 hours. Toluene was removed under reduced pressure from the resulting reaction mixture to obtain silicone-modified epoxy resin c-2. The silicone-modified epoxy resin c-2 is a composition including a structure represented by Formula (14), Formula (15), and Formula (16).

（式（１３）中、ｎは１０（平均値）である。）

(In formula (13), n is 10 (average value).)

（式（１４）中、ｍは６〜９であり、ｎは１〜４である。式（１４）で表される構造は、＊でシリコーンに単結合で架橋される。）

(In the formula (14), m is 6 to 9, and n is 1 to 4. The structure represented by the formula (14) is crosslinked with a single bond to silicone by *.)

（式（１５）中、ｋは６〜９であり、ｊは１〜４である。式（１５）で表される構造は、＊でシリコーンに単結合で架橋される。）

(In the formula (15), k is 6 to 9, and j is 1 to 4. The structure represented by the formula (15) is crosslinked to the silicone with a single bond with *.)

（式（１６）で表される構造は、＊でシリコーンに単結合で架橋される。）

(The structure represented by the formula (16) is crosslinked to the silicone by a single bond with *.)

[Synthesis Example 3] Synthesis of silicone-modified epoxy resin c-3 A phenol novolak resin (phenol equivalent 125, allyl) modified with allyl glycidyl ether was added to a flask equipped with a stirring blade, dropping funnel, thermometer, ester adapter and reflux tube. Equivalent 1100) 200 g, chloromethyloxirane 800 g, and cetyltrimethylammonium bromide 0.6 g were added and heated, and 128 g of a 50% aqueous solution of sodium hydroxide was added dropwise thereto over 3 hours. After the solvent was distilled off, the intermediate product in the flask was dissolved in a mixed solvent of 300 g of methyl isobutyl ketone and 300 g of acetone, washed with water, and the solvent was distilled off to give an allyl group-containing epoxy resin (allyl equivalent 1590, Epoxy equivalent 190) was obtained. This epoxy resin, 170 g of methyl isobutyl ketone, 330 g of toluene, and 0.07 g of a catalyst (CAT-PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.) were added and subjected to azeotropic dehydration for 1 hour, and represented by the following formula (17) at the reflux temperature. 133 g of the organopolysiloxane was added dropwise at a dropping time of 30 minutes, and the mixture was stirred and reacted at the same temperature for 4 hours. Then, the solvent was distilled off, and the silicone-modified epoxy resin c- containing the structure represented by the formula (17) 3 was obtained.

The raw materials used in Examples and Comparative Examples of the present invention are shown below.
(A) Liquid epoxy resin that is liquid at 25 ° C. (a-1) Glycidylamine type epoxy resin (epoxy equivalent 100, jER-630LSD manufactured by Mitsubishi Chemical Corporation, viscosity at 25 ° C. 500 mPa · s)
(A-2) Bisphenol type epoxy resin (epoxy equivalent 165, Nippon Steel & Sumikin Chemical Co., Ltd. ZX-1059, viscosity at 25 ° C., 2,000 mPa · s)

(B) Polyamine curing agent that is solid at 25 ° C. and has a melting point of 50 to 120 ° C. (b-1) Solid polyamine curing agent (melting point 85 to 105 ° C., active hydrogen equivalent 52, EH-manufactured by ADEKA Corporation 5015S)
(B-2) Solid polyamine curing agent (melting point: 70 to 80 ° C., active hydrogen equivalent: 105, EH-5030S manufactured by ADEKA Corporation)
Curing agent that does not satisfy the conditions of component (B) (b-3) Liquid aromatic amine curing agent (melting point: -40 to -10 ° C, active hydrogen equivalent 63, Kayahard AA manufactured by Nippon Kayaku Co., Ltd.)
(B-4) Liquid polyamine curing agent (melting point −40 to −10 ° C., active hydrogen equivalent 78, EH-451N manufactured by ADEKA Corporation)

(C) Silicone-modified epoxy resin (c-1) Silicone-modified epoxy resin of Synthesis Example 1)
(C-2) Silicone-modified epoxy resin of Synthesis Example 2)
(C-3) Silicone-modified epoxy resin of Synthesis Example 3)

(D) Inorganic filler (d-1) Spherical fused silica (average particle size 10 μm, RS-8225 / 53C manufactured by Tatsumori)

(E) Other additive adhesion assistant (e-1) 3-glycidoxypropyltrimethoxysilane (silane coupling agent, KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.)

[Examples 1 to 9, Comparative Examples 1 to 4]
In the formulation (parts by mass) shown in Table 1, components (A) to (E) were mixed to obtain thermosetting epoxy resin compositions of Examples 1 to 9 and Comparative Examples 1 to 4. About the obtained thermosetting epoxy resin composition, various characteristics were measured with the following method. Subsequently, the thermosetting epoxy resin compositions of Examples 1 to 9 and Comparative Examples 1 to 4 were molded while curing each thermosetting epoxy resin composition under conditions of a molding temperature of 90 ° C. and a molding time of 3 hours. A cured product was obtained. About the obtained hardened | cured material, various characteristics were measured with the following method. In the DSC for obtaining the reaction rate, the cured product was cured at a temperature of 90 ° C. and a reaction time of 1 hour. Table 1 shows the measurement results of Examples 1 to 9 and Comparative Examples 1 to 4 and these cured products.

<Viscosity>
Within 48 hours after the production of each of the examples and comparative examples, the viscosity of the composition at 25 ° C. was measured at a rotation speed of 1.0 rpm using a cone plate viscometer (51CP manufactured by BROOK FIELD). It was set as the viscosity after manufacture.

<Storage stability at 25 ° C>
Each Example and Comparative Example in which the viscosity was measured by the above method was measured for 24 hours after storage at 25 ° C., and the viscosity was determined after 24 hours. The thickening rate was calculated by the following formula.
Thickening rate (%) = (viscosity after 24 hours−viscosity after production) / (viscosity after production) × 100

  When the thickening ratio calculated by the above calculation formula was less than 30%, it was evaluated that the storage stability at 25 ° C. was good, and indicated as “◯” in Table 1. On the other hand, if the thermosetting epoxy resin composition of the sample is cured after being stored for 24 hours at 30% or more or at 25 ° C, the storage stability at 25 ° C is poor when the viscosity cannot be measured. And expressed as “x” in Table 1.

<90 ° C. 1 hour reaction rate>
Using a differential scanning calorimeter (DSC), the DSC exothermic peak areas of the compositions before curing of each example and comparative example were measured. For the measurement, UV-DSC manufactured by METTTL was used. Subsequently, each example and comparative example were heated at 90 ° C. for 1 hour, and then the DSC exothermic peak area of the obtained cured product was measured. The reaction rate was calculated by the following formula using the DSC exothermic peak area value.
Reaction rate (%) = (DSC peak area value before curing) − (DSC peak area value after curing) / (DSC peak area value before curing) × 100

<Crack resistance>
On the PCB substrate, each of the examples and comparative examples was applied to an area of 2 cm × 2 cm and a thickness of 2 mm, and 15 test pieces were prepared for each of the examples and comparative examples, and were put into a temperature cycle tester. . Regarding the test conditions, after maintaining at -55 ° C for 30 minutes, the temperature was raised from -55 ° C to 125 ° C and held for 5 minutes. Subsequently, an operation of holding at 125 ° C. for 30 minutes, further lowering the temperature from 125 ° C. to −55 ° C. and holding for 5 minutes was defined as one cycle, and 1,000 cycles were performed. Thereafter, the presence or absence of cracks or peeling defects in each test piece was visually observed, and the number of test pieces / total test pieces in which no defect was found was counted.

<Adhesive strength>
4 mm ² of each of the examples and comparative examples is applied to a nickel-coated copper plate, a 2 mm × 2 mm × 150 μm Si chip is adhered to the coated surface, and cured under conditions of a molding temperature of 90 ° C. and a molding time of 3 hours. Each test piece was obtained. The shear adhesive strength of each test piece at room temperature (25 ° C.) was measured using a bond tester DAGE-SERIES-4000PXY (manufactured by DAGE JAPAN).

<Presence / absence of voids>
The thermosetting epoxy resin compositions of the examples and comparative examples were poured into a 2 cm × 2 cm × 2 mm mold, and 0.1 mL of air was introduced five times with a syringe into the bottom of the mold into which the epoxy resin was poured. did. Thereafter, the thermosetting epoxy resin composition was cured under conditions of a molding temperature of 90 ° C. and a molding time of 3 hours. The presence or absence of voids on the surface of the obtained cured product or inside was observed with C-SAM (manufactured by SONIX, Inc.). When no void was confirmed on the surface or inside of the cured product, “No” was shown in Table 1, and when a void was confirmed, “Yes” was shown in Table 1.

<Bending elastic modulus at room temperature>
The flexural modulus of the cured product at room temperature (25 ° C.) was measured by the method described in JIS K 7171: 2008.

As shown in Table 1, in Comparative Examples 1 and 4 in which the silicone-modified epoxy resin of component (C) was not blended, crack resistance and adhesive strength were insufficient, and voids occurred in the cured product. Further, when a liquid aromatic amine curing agent was used as in Comparative Example 2, it was not cured at 90 ° C. Moreover, when a liquid polyamine type hardening | curing agent was used like the comparative example 3, the reactivity was too high and the storage stability calculated | required by this invention was not satisfy | filled.
On the other hand, Examples 1 to 9 in which the silicone-modified epoxy resin corresponding to the component (C) was blended had good foaming. Further, the cured product had low elasticity and high crack resistance, and voids were hardly generated. As shown in Examples 1 to 9 above, the present invention is suitable for low-temperature curing potting material applications.

Claims (4)

(A) a liquid epoxy resin that is liquid at 25 ° C.,
(B) a polyamine curing agent that is solid at 25 ° C. and has a melting point of 50 to 120 ° C.,
(C) a silicone-modified epoxy resin, and (D) an inorganic filler,
The thermosetting epoxy resin composition, wherein the component (C) is a hydrosilylation reaction adduct of an epoxy resin having a carbon-carbon double bond and a silicone resin having a hydrosilyl group.   2. The thermosetting epoxy resin composition according to claim 1, wherein the reaction rate after heating at 90 ° C. for 1 hour calculated from the DSC exothermic peak area is 90% or more. The thermosetting epoxy resin composition according to claim 1 or 2, wherein the epoxy resin having a carbon-carbon double bond is a compound represented by the following structural formula (1) or (2).

(In the structural formula (1), R ¹ is a hydrocarbon group having an epoxy group and may be the same or different. R ² is a methyl group or a hydrogen atom, and may be the same or different.)

(In the structural formula (2), R ¹ is a hydrocarbon group having an epoxy group, and may be the same or different. X is a hydrogen atom or a bromine atom, and may be the same or different. (It is an integer of 0 or more.) The component (A) is one or more liquid epoxy resins selected from glycidylamine type liquid epoxy resins and bisphenol type liquid epoxy resins represented by the following structural formula (3) or (4): Item 4. The thermosetting epoxy resin composition according to any one of Items 1 to 3.

(In the structural formula (3), R is a halogen atom, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, or an alkoxy group, and may be the same or different. X is 0 to 4 Is an integer.)

(In the structural formula (4), R is a halogen atom, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms, or an alkoxy group, and may be the same or different. It is an integer of 0 to 4. A is a single bond, an ether group, a thioether group, an SO ₂ group, or an unsubstituted or substituted divalent hydrocarbon group having 1 to 6 carbon atoms.