JP2939166B2 - Latent catalyst and thermosetting resin composition containing the catalyst - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a latent catalyst and a thermosetting resin composition containing the catalyst. More specifically, the present invention is intended for blending various thermosetting resins, especially epoxy resins and maleimide resins, to stably store the resin composition for a long period of time without exhibiting a catalytic action at normal temperature. A latent catalyst that is capable of exhibiting an excellent catalytic action when heated during molding to provide good moldability and high quality molded articles, and
The present invention relates to a thermosetting resin composition containing the latent catalyst, particularly useful for electronic and electric parts.

[0002]

2. Description of the Related Art A thermosetting resin is generally used by blending a catalyst in order to accelerate the curing of the resin during molding.
For example, in the case of epoxy resin, curing catalysts include amines (JP-A-58-173852), imidazole-based compounds (JP-A-56-160056, JP-A-57-59365, and JP-A-57-59365). 57-100128), diazabicycloundecene (JP-A-56-94).
No. 761, JP-A-59-75923), nitrogen-containing heterocyclic compounds, organosilicone-based compounds (JP-A-56-133855), and organophosphine-based compounds (JP-A-56-130953). Quaternary ammonium, phosphonium or arsonium compounds (JP-A-55-1).
53358, JP-A-57-194555,
Various compounds have been used, such as JP-A-58-119656. Further, the maleimide resin can be cured only by heat, but the properties of the molded product obtained by curing are generally better when cured using a catalyst. Examples of the curing catalyst for the maleimide resin include azo compounds, radical polymerization initiators such as organic peroxides (JP-A-5-51418), amines, imidazole-based compounds (JP-A-4-351629), and organo Phosphine compounds (JP-A-61-233017, JP-A-1-45426), ion catalysts such as quaternary ammonium or phosphonium compounds, etc.
Various compounds have been used. Generally used catalysts often show a curing acceleration effect even at a relatively low temperature such as room temperature, for example, to advance the curing of the resin by heating or heating when mixing the resin and other compounding components In order to advance the curing reaction even after the resin composition is stored at room temperature after mixing, the quality of the resin composition, particularly, the melt viscosity is increased, and the curability tends to vary due to the decrease in fluidity. Failure and deterioration of the mechanical, electrical and chemical properties of the molded article. Therefore,
When using such a catalyst, strictly control the quality when mixing with various components, keep the temperature low during storage and transportation, and avoid the complexity of requiring strict control of the molding conditions. I couldn't. Therefore, in recent years, a so-called latent catalyst which does not progress the curing reaction of the resin at a relatively low temperature such as room temperature and accelerates the curing reaction when heated during molding has been developed and used. However, even if a catalyst called a latent catalyst is used, the curing reaction of the resin gradually proceeds at room temperature due to its low latency, or the activity is too low. In some cases, the curing is not accelerated so that curing takes a long time or the curing temperature needs to be increased. That is,
A catalyst that suppresses the curing reaction at room temperature and exhibits catalytic activity at a high temperature during molding and exhibits strong catalytic activity once developed is ideal as a latent catalyst. Many studies have been made to develop such catalysts, and latent catalysts which have been capped with a protecting group, such as ionizing active sites of the catalyst, have been developed. For example, Japanese Patent Publication No. 51-24399 discloses that tetraphenylphosphonium tetraphenylborate is effective for improving room temperature storage stability and curability. However, tetraphenylphosphonium tetraphenylborate has a strong ionic bond between a cationic tetraphenylphosphonium group and an anionic tetraphenylborate group, and has a melting point of 300 ° C. or more, and is uniform even when kneaded into a thermosetting resin composition. , The catalyst activity becomes low, and good curing reactivity cannot be exhibited during molding. Therefore, generally, as shown in JP-A-55-153358,
A method is used in which tetraphenylphosphonium tetraphenylborate is previously melt-mixed with a part of the raw material and then kneaded into the thermosetting resin composition. However, in this method, tetraphenylphosphonium tetraphenylborate has a structure in which ionic bonds have already been released during melt mixing, so that reactivity at room temperature cannot be suppressed and storage stability is reduced. The ionic bond between the anion part and the cation part is moderately strong and shows favorable behavior as a latent catalyst.
Research has been conducted on a catalyst that does not require melt mixing with some of the raw materials and can be dry-blended with a thermosetting resin.
No. 90 proposes a tetrasubstituted phosphonium tetrasubstituted borate as a latent catalyst. The substituent on the boron side of the proposed tetra-substituted phosphonium tetra-substituted borate is a hydrocarbon group, at least one of which is an alkyl group having 1 to 6 carbon atoms, which can be dry-blended with a thermosetting resin. Although it is considered to be excellent in storage stability, storage stability is still not sufficient from the viewpoint of storage stability at room temperature for a long period of time. On the other hand, IC, L
There are sealing materials for semiconductor elements such as SI and electric parts. Conventionally, epoxy resin compositions have been widely used from the viewpoint of balance between properties and costs. In such an epoxy resin encapsulant, curing accelerators conventionally used include 2-methylimidazole, 1,8-diazabicyclo [5.4.0] -7-undecene, triphenylphosphine, and the like. Since these curing accelerators exhibit a curing acceleration effect even at relatively low temperatures as described above, epoxy resin encapsulants using them have poor storage stability at room temperature. The drop causes problems such as poor filling, breakage of the gold wire of the IC chip, and poor conduction. For this reason, the epoxy resin encapsulant needs to be refrigerated and transported in a refrigerated state, and at present, great cost is required for storage and transportation. Furthermore, in recent years, the biggest problem in semiconductor encapsulation materials such as ICs and LSIs is the problem of so-called solder cracks that occur when packages are mounted. In order to improve the solder resistance, a resin composition containing a large amount of an inorganic filler has been developed. As a method of allowing a large amount of the inorganic filler to be compounded, there are a method of selecting a particle size distribution and a shape of the inorganic filler, and a method of reducing the viscosity of the epoxy resin. However, when the molecular weight of the resin is reduced to reduce the viscosity of the resin, the molecules are easily moved, and the crosslinking reaction proceeds rapidly in the initial stage of the reaction. Does not develop, and for the same reason, the reaction is likely to occur even at room temperature, so that the room temperature storage stability of the resin composition is reduced. Further, a resin having a low molecular weight has a high initial reactivity, but at the final stage of the reaction, conversely, the crosslinking density is not sufficiently increased, and thus the sealing resin is not sufficiently cured.

[0003]

According to the present invention, a dry blend with a thermosetting resin is possible, and the resin composition can be stably stored at room temperature for a long period of time without exhibiting a catalytic action. Yes, a latent catalyst capable of exerting an excellent catalytic action when heated during molding to provide good curability and a high quality molded article, and a blend of the latent catalyst, particularly for electronic and electric parts The purpose of the present invention is to provide a thermosetting resin composition useful as a resin.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, when a tetra-substituted phosphonium tetra-substituted borate having a specific structure is added to a thermosetting resin, It has been found that the composition exhibits excellent storage stability at room temperature, and exhibits excellent curability at the time of heat molding. Based on this finding, the present invention has been completed. That is, the present invention provides (1) a latent catalyst comprising a phosphonium borate represented by the general formula [1]:

Embedded image (However, in the formula, R ¹ , R ² , R ³ and R ⁴ are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring, and they are different even if they are the same. Y ¹ , Y ² , Y ³ and Y ⁴ are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring,
At least one of them is a group in which a proton donor having at least one proton that can be released outside the molecule releases one proton, and they may be the same or different from each other . (2) the latent catalyst according to (1), wherein the proton donor is a carboxylic acid having at least one carboxyl group in one molecule; and (3) the latent catalyst, wherein the carboxylic acid is an aromatic carboxylic acid. (2) the latent catalyst according to (1), wherein the proton donor is a phenolic compound having at least one hydroxyl group in one molecule;
(5) The first (1) wherein the proton donor is isocyanuric acid.
(7) The latent catalyst according to (1), wherein the proton donor is benzotriazole, (7)
(8) thermosetting resin composition, comprising 100 parts by weight of a thermosetting resin and 0.4 to 20 parts by weight of a latent catalyst according to the items (1) to (6). The thermosetting resin composition according to item (7), wherein the resin is at least one resin selected from the group consisting of an epoxy resin and a maleimide resin, (9) the thermosetting resin composition further comprises oxirane The thermosetting resin composition according to item (8), comprising a reactive curing agent, wherein (10) the oxirane reactive curing agent is selected from the group consisting of diamines, polyamines, acid anhydrides and phenolic compounds. (9) The thermosetting resin composition according to (9), wherein the maleimide resin is a resin containing an alkenylphenol; (11) the thermosetting resin composition according to (8), (12) (A) having two or more epoxy groups in one molecule An epoxy resin, (B) a phenolic resin having two or more phenolic hydroxyl groups in one molecule, (C) a latent catalyst according to any one of (1) to (6), and (D) an inorganic filler, The equivalent ratio of the epoxy group of the epoxy resin (A) to the phenolic hydroxyl group of the phenol resin (B) is 0.5 to 2, and the content of the latent catalyst (C) is 100% of the total amount of the epoxy resin and the phenol resin. Thermosetting characterized in that it is 0.4 to 20 parts by weight per part by weight, and the content of the inorganic filler (D) is 200 to 2400 parts by weight per 100 parts by weight of the total amount of the epoxy resin and the phenol resin. Resin composition, (13) epoxy resin (A),
(1) which is a crystalline epoxy resin having a melting point of 50 to 150 ° C.
The thermosetting resin composition according to the item 2), (14) an inorganic filler
The content of (D) is 250 to 1400 parts by weight per 100 parts by weight of the total amount of the epoxy resin and the phenol resin.
(12) The thermosetting resin composition according to (13), and
(15) The thermosetting resin composition according to any one of (13) to (14), wherein the crystalline epoxy resin is a compound represented by the general formula [2] or [3].

Embedded image (Wherein, R ⁵ is hydrogen or a methyl group.)

Embedded image (Wherein, R ⁶ is hydrogen or a methyl group).

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The latent catalyst of the present invention comprises a phosphonium borate represented by the general formula [1].

Embedded image However, in the general formula [1], R ¹ , R ² , R ³ and R ⁴ of the phosphonium group are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring. They may be the same or different. Examples of such a phosphonium group include, for example, a tetraphenylphosphonium group, a tetratolylphosphonium group, a tetraethylphenylphosphonium group, a tetramethoxyphenylphosphonium group, a tetranaphthylphosphonium group, a tetrabenzylphosphonium group, an ethyltriphenylphosphonium group, and n-butyl. Examples include a triphenylphosphonium group, a 2-hydroxyethyltriphenylphosphonium group, a trimethylphenylphosphonium group, a methyldiethylphenylphosphonium group, a methyldiallylphenylphosphonium group, and a tetra-n-butylphosphonium group. In the general formula [1], R ¹ , R ² , R ³ and R ⁴ are particularly preferably a monovalent organic group having an aromatic ring, and the melting point of the phosphonium borate represented by the general formula [1] Is not particularly limited, but is preferably 250 ° C. or lower from the viewpoint of uniform dispersion.
In particular, a phosphonium borate having a tetraphenylphosphonium group has good compatibility with a thermosetting resin and can be suitably used. In the general formula [1], Y ¹ , Y ² , Y ³ and Y ⁴ of the borate group are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring, and among them, At least one is a group in which a proton donor having at least one proton that can be released outside the molecule releases one proton, and Y ¹ , Y ² ,
Y ³ and Y ⁴ may be the same or different from each other. Examples of such a proton donor providing a borate group include acetic acid, trifluoroacetic acid, stearic acid, benzoic acid, 1-naphthoic acid, 2-naphthoic acid, phthalic acid, trimellitic acid, pyromellitic acid, 6-naphthalenedicarboxylic acid, partially ring-opened carboxylic acids such as polyacrylic acid and anhydrides thereof, phenol, 1-naphthol, 2-naphthol, polyphenols, isocyanuric acid, benzotriazole, and compounds having an aromatic ring among them And the like having a substituent on the aromatic ring.

When the latent catalyst comprising phosphonium borate represented by the general formula [1] of the present invention is incorporated into a thermosetting resin, it does not exhibit catalytic activity at room temperature, so that the curing reaction of the thermosetting resin is not effected. Without progressing, the catalyst activity is exhibited at a high temperature during molding, and once exhibited, exhibits a stronger catalytic activity than conventional curing accelerators, and highly cures the thermosetting resin. The latent catalyst comprising a phosphonium borate represented by the general formula [1] according to the present invention is characterized in that an anionic tetra-substituted borate group acts as a protective group at room temperature to form a cationic tetra-substituted phosphonium group as an active site and an ion. Cap by forming a bond. In addition, the protective group does not come off due to heating or heat generation when mixing the thermosetting resin with other compounding components. That is, the energy required for dissociation of the ionic bond between the cationic tetra-substituted phosphonium group and the anionic tetra-substituted borate group can be obtained only during molding. At this time, the protective group of the phosphonium borate is removed, the active site is exposed, and the curing reaction proceeds. For this purpose, it is important that the ionic bond between the cationic tetra-substituted phosphonium group and the anionic tetra-substituted borate group is not too strong, and the conventional curing accelerator, tetraphenylphosphonium tetraphenyl borate, has an ionic bond. too strong. For this reason, the melting point becomes 300 ° C. or more, and even if kneaded with the resin composition, uniform dispersion cannot be performed, and the effect as a curing accelerator cannot be sufficiently exhibited. Therefore, it is common to melt and mix tetraphenylphosphonium tetraphenylborate with a part of the raw material before kneading the resin composition. However, in this method, when the tetraphenylphosphonium tetraphenylborate has a structure in which the tetraphenylborate group of the protective group has already been removed at the time of melt-kneading, the reactivity at a low temperature increases, and the storage stability at room temperature decreases. The desired effect is not sufficiently exhibited. Therefore, a structure in which the bonding force between the tetraphenylphosphonium group and its protective group is appropriately weakened as described above is desired. Specifically, if the type of the functional group bonded to boron is changed to a functional group having a higher electron-withdrawing property than the phenyl group, the anionicity of the borate anion is reduced, and the ionic bond with the tetraphenylphosphonium group is weakened. At the same time, the melting point becomes 200 to 250 ° C., and the resin composition can be uniformly kneaded.

In the tetra-substituted phosphonium tetra-substituted borate which is a latent catalyst of the present invention, the anionic tetra-substituted borate which is a protective group has a substituent bonded to boron with an electron withdrawing from the phenyl group of tetraphenyl phosphonium tetraphenyl borate. Is a highly substituted group, the anionicity of the tetra-substituted borate group is reduced, the ionic bond between the cationic tetra-substituted phosphonium group and the anionic tetra-substituted borate group is weakened to some extent,
The melting point is also 180-260 ° C, lower than 300 ° C or higher of tetraphenylphosphonium tetraphenylborate, and the curability is rapid only by dry blending with the thermosetting resin without melt mixing with the thermosetting resin in advance. It is considered to indicate. In addition, the latent catalyst of the present invention uses the energy required for dissociating the cationic tetra-substituted phosphonium group and the anionic tetra-substituted borate group when mixing the thermosetting resin and other components. Alternatively, since it cannot be obtained by heat generation, the protecting group does not come off and the reactivity at low temperatures is low. At a high temperature during molding, energy required for dissociation can be obtained, so that the protective group is removed and shows high reactivity. In other words, the reactivity at low temperatures is low, but the reactivity at high temperatures is very high, indicating an ideal reaction behavior as a latent catalyst. Therefore, it is possible to improve the storage stability at room temperature, reduce the viscosity of the sealing resin due to little reaction during kneading, and achieve high reactivity when heated to a high temperature. The latent catalyst comprising phosphonium borate of the present invention is particularly useful for epoxy resins, especially epoxy resins containing phenolic or carboxylic anhydride curing agents. Further, the latent catalyst comprising the phosphonium borate of the present invention is also useful for maleimide resins, especially for maleimide resins containing alkenylphenols as comonomers.

[0008] The thermosetting resin composition of the present invention contains 100 parts by weight of a thermosetting resin and 0.4 to 20 parts by weight of a latent catalyst. The mixing of the thermosetting resin and the latent catalyst is usually performed at a moderately high temperature, for example, at 70 to 150 ° C., preferably at 80 ° C.
~ 110 ° C. If the content of the latent catalyst is less than 0.4 part by weight per 100 parts by weight of the thermosetting resin, sufficient curability may not be obtained during heat molding. When the content of the latent catalyst is 100
If the amount is more than 20 parts by weight per part by weight, curing may be too fast and poor fluidity during molding may cause poor filling. The latent catalyst of the present invention may be used alone, or two or more kinds may be used in combination.
Further, it can be used in combination with other curing accelerators as long as the object of the present invention is not impaired. The latent catalyst comprising the phosphonium borate of the present invention can be used for any thermosetting resin whose thermosetting is promoted by the latent catalyst without any particular limitation. Latent catalyst of the present invention,
It is particularly useful for thermosetting resins in which a phosphine or phosphonium salt catalyst has conventionally been effective. Examples of such thermosetting resins include, for example, epoxy resins and maleimide-based resins.In addition to these resins, furthermore, resins whose reactive monomers are cyanates, isocyanates, and acrylates, Alkenyl resins, alkynyl resins and the like can be mentioned. The epoxy resin used in the thermosetting resin composition of the present invention is generally a compound having two or more oxirane rings in one molecule, and has a molecular weight of about 340 to 7,000, from a liquid to a solid. Can be used. Such epoxy resins include, for example, bisphenol A type epoxy resin, bromine-containing epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, biphenyl type epoxy resin, dihydroxydiphenylmethane type epoxy resin, phenol novolak type epoxy resin, Cresol novolak type epoxy resin, cycloaliphatic epoxy resin, glycidyl ester epoxy resin, glycidylamine epoxy resin, heterocyclic epoxy resin, and the like can be given. The maleimide-based resin used in the thermosetting resin composition of the present invention is a resin having at least one maleimide group in a molecule, and is not particularly limited. Examples thereof include a bismaleimide resin. . The thermosetting resin composition of the present invention can contain an oxirane-reactive curing agent. There is no particular limitation on the oxirane-reactive curing agent to be used. Examples thereof include phenolic compounds such as cyclic acid anhydrides and phenol novolak resins.

The thermosetting resin composition of the present invention comprises an epoxy resin having two or more epoxy resins in one molecule and a phenol resin having two or more phenolic hydroxyl groups in one molecule. It contains the latent catalyst of the present invention and an inorganic filler, and the equivalent ratio of the epoxy group of the epoxy resin to the phenolic hydroxyl group of the phenol resin is 0.5 to 2;
Wherein the content of the latent catalyst is 0.4 to 20 parts by weight per 100 parts by weight of the total amount of the epoxy resin and the phenol resin, and the content of the inorganic filler is 100 parts by weight of the total amount of the epoxy resin and the phenol resin. 200 to 2400 per copy
It is preferably in parts by weight. The phenolic resin having two or more phenolic hydroxyl groups in one molecule used in the thermosetting resin composition of the present invention is not particularly limited, for example,
Phenol novolak resin, cresol novolak resin, para-xylylene-modified phenol resin, meta-xylylene / para-xylylene-modified phenol resin, terpene-modified phenol resin, dicyclopentadiene-modified phenol resin, and the like can be given. These phenolic resins can be used without any limitation in molecular weight, softening point, hydroxyl equivalent and the like. Also, these phenolic resins
One type may be used alone, and two or more types may be used in combination. When the thermosetting resin composition of the present invention is used for electronic and electric parts, it is preferable that the chlorine content in the resin is low from the viewpoint of long-term reliability. When the thermosetting resin composition of the present invention is used as a sealing resin for surface mounting, the phenol resin is more preferably a xylylene-modified phenol resin. The xylylene-modified phenolic resin has few hydroxyl groups, so the water absorption of the molded product is small, and because of the structure where xylylene and phenol are bonded, the molecule has a moderate flexibility, and there is little steric hindrance in the curing reaction. In addition, the curability is less hindered, and the viscosity can be lowered by further reducing the average molecular weight. Even if the average molecular weight is reduced, the curability is hardly reduced due to the chemical structure. The phenolic hydroxyl group of the phenol resin reacts with the oxirane ring of the epoxy resin to form a crosslinked structure.
If the equivalent ratio of the epoxy group of the epoxy resin to the phenolic hydroxyl group of the phenolic resin is less than 0.5 or more than 2, the curability of the resin composition decreases, or the glass transition temperature of the cured product decreases. May occur.

The inorganic filler used in the thermosetting resin composition of the present invention is not particularly limited, and a known inorganic filler can be used. Examples of such an inorganic filler include alumina, fused silica, spherical silica, crystalline silica, secondary aggregated silica, clay, and talc. When the composition of the present invention is used as a resin for semiconductor encapsulation, the inorganic filler is preferably spherical silica from the viewpoint of improving fluidity. The shape of spherical silica is
In order to improve the fluidity, it is preferable that the shape of the particles themselves is infinitely spherical and the particle size distribution is broad.
If the content of the inorganic filler is less than 200 parts by weight per 100 parts by weight of the total amount of the epoxy resin and the phenol resin, the reinforcing effect of the inorganic filler may not be sufficiently exhibited. If the content of the inorganic filler exceeds 2,400 parts by weight per 100 parts by weight of the total amount of the epoxy resin and the phenolic resin, the fluidity of the resin may be reduced, and poor filling may occur during molding. In the thermosetting resin composition containing the epoxy resin and the phenol resin of the present invention, the epoxy resin is particularly preferably a crystalline epoxy resin having a melting point of 50 to 150 ° C. Such a crystalline epoxy resin has molecules having a planar structure such as phenyl, biphenyl, bisphenol, and naphthalene in its main chain, and has a relatively low molecular weight, and thus exhibits crystallinity. The crystalline epoxy resin is a crystalline solid at room temperature, but once melted, has the property of becoming a very low-viscosity liquid. Even when using a conventional epoxy resin, for example, an orthocresol novolac type epoxy resin having a low viscosity type, the melt viscosity does not sufficiently decrease, and the epoxy resin itself is easily melted at room temperature, so molding may be difficult. However, these difficulties can be solved by using a crystalline epoxy resin. As the crystalline epoxy resin, a biphenyl type epoxy resin represented by the general formula [2] and a dihydroxydiphenylmethane type epoxy resin represented by the general formula [3] can be particularly preferably used.

Embedded image R ⁵ in the general formula [2] and R ⁶ in the general formula [3]
Is hydrogen or a methyl group. In the composition of the present invention,
Epoxy resin represented by general formula [2] and general formula [3]
Can be used alone or as a mixture of both. When the melting point of the crystalline epoxy resin is 50 ° C. or more, it does not melt at room temperature and is excellent in workability in a premixing step and the like. When the melting point of the crystalline epoxy resin is 150 ° C. or less, the crystalline epoxy resin can be easily melted and kneaded uniformly in a kneading apparatus.

In the thermosetting resin composition containing the epoxy resin and the phenolic resin of the present invention, the content of the inorganic filler is from 250 to 1200 parts by weight per 100 parts by weight of the total of the epoxy resin and the phenolic resin. Is particularly preferred. When the content of the inorganic filler is 250 parts by weight or more per 100 parts by weight of the total amount of the epoxy resin and the phenol resin, the water absorption of the resin composition decreases, and when used as a resin for semiconductor encapsulation, the soldering resistance And the occurrence of cracks can be prevented. The content of the inorganic filler is a total amount of the epoxy resin and the phenol resin of 100.
When the amount is 1200 parts by weight or less per part by weight, the viscosity of the resin composition at the time of melting is low, and there is no possibility of causing gold wire deformation inside the semiconductor package. The latent catalyst of the present invention can be used alone, or can be used as a mixture with another curing accelerator. When used in combination with another curing accelerator, the latent catalyst of the present invention preferably accounts for 50% by weight or more of the total amount of the latent catalyst and the other curing accelerator. If the latent catalyst of the present invention is less than 50% by weight, the object of the present invention may not be sufficiently achieved. Other curing accelerators that can be used in combination with the latent catalyst of the present invention include, for example, triphenylphosphine, tetraphenylphosphonium tetraphenylborate, 1,8-diazabicyclo [5.4.0] undecene-7, and the like. Can be mentioned. The thermosetting resin composition of the present invention may be, if necessary, a coloring agent such as carbon black, a brominated epoxy resin, a flame retardant such as antimony trioxide, and a coupling agent such as γ-glycidoxypropyltrimethoxysilane. And various additives such as a low stress component such as silicone oil and rubber, a release agent, an antioxidant, a surfactant and a coupling agent.
The epoxy resin composition of the present invention is prepared by mixing an epoxy resin, a phenol resin, a latent catalyst, an inorganic filler, and other additives at room temperature with a mixer, kneading with a kneader such as a roll and an extruder, and cooling. It can be ground to form a molding material.

[0012]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. The abbreviations and structures of the latent catalyst and the curing accelerator used in Examples and Comparative Examples are shown below.

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Embedded image TPP-TBB: tetraphenylphosphonium tetrabutyl borate TPP-BTPB: tetraphenyl phosphonium butyl triphenyl borate TPP-K / PN: tetraphenyl phosphonium tetraphenyl borate and phenol novolak resin PR-5
1714 melt-mixed at a weight ratio of 1: 9 at 230 ° C. TPP-K / XL: tetraphenylphosphonium tetraphenylborate and paraxylylene-type phenol resin X
L-225-3L was melt-mixed at a weight ratio of 1: 9 at 230 ° C. The material was evaluated by the following method. (1) Gelation time After melting the resin composition on a hot plate, the time until the resin composition is cured while kneading with a spatula is measured. (2) Stabilization time The stabilization time is measured using a Labo Plast Mill tester [manufactured by Toyo Seiki Seisaku-sho, Ltd.]. The measurement is performed at a test rotation speed of 60 rpm and a mixer type of R-30. The measurement temperature is two levels of 90 ° C. assuming a heat history at the time of heating and mixing in order to homogenize components at the time of materialization of the molding material, and 175 ° C. assuming a heat history at the time of molding the molding material. I do. Since the low-temperature preservability includes the thermal history of the thermosetting resin, the low-temperature preservability promotion test corresponds to the measurement at 90 ° C. The stabilization time is defined as the time from when the material is put into the tester to when the curing reaction starts and the resin torque suddenly rises and the torque value becomes 3 kg-m. The longer the stabilization time, the harder the curing reaction at that temperature occurs. (3) Storage at 25 ° C. (DSC) A raw material mixture was once melted at 90 ° C., then cooled and pulverized, and then subjected to differential thermal analysis (DS) at a rate of temperature increase of 10 ° C./min.
The curing heat value is measured in C). Further, the pulverized sample is stored in a 25 ° C. oven for 6 months, and the calorific value of the cured product after storage is measured by DSC. A value of {(calorific value after storage) / (calorific value immediately after pulverization)} × 100 (%) is used as an index of the preservability after 6 months at 25 ° C. For those having poor storage properties, the curing reaction proceeds during storage at 25 ° C., and the calorific value of curing after storage decreases, so that the percentage value becomes small. (4) Spiral flow Using a mold for spiral flow measurement according to EMMI-I-66, mold temperature 175 ° C, injection pressure 70 kg / cm
^2. Measure with a curing time of 2 minutes. Spiral flow is a parameter of fluidity, and the larger the value, the better the fluidity. (5) Curing Torque A torque after 90 seconds at 175 ° C. is determined by using a curastometer [JSR Curastometer IVPS, manufactured by Orientec Co., Ltd.]. The torque in the curast meter is a parameter of curability, and the larger the value, the better the curability. (6) Storage at 30 ° C. After storing the material at 30 ° C. for 6 months, the spiral flow was measured and expressed as a percentage of the spiral flow immediately after the preparation of the material. (7) Storage at 25 ° C. After storing the material at 25 ° C. for one week, the spiral flow was measured and expressed as a percentage of the spiral flow immediately after the preparation of the material. (8) Curability The material is cured at a mold temperature of 175 ° C. and a curing time of 2 minutes, and the condition is adjusted. The value of the Shore D hardness measured is defined as the curability. (9) Solder resistance 8 pieces of 80pQFP (1.5mm thick) were treated at 85 ° C and 85% relative humidity for 168 hours, and then treated at 240 ° C IR reflow at 240 ° C for 10 seconds to determine the number of package cracks. Observed visually, the cracked package was n
If the number is n, it is displayed as n / 8. Example 1 Orthocresol novolak type epoxy resin having a softening point of 65 ° C. and an epoxy equivalent of 210 [Nippon Kayaku Co., Ltd., EOC
N-125-65], 67 parts by weight, 33 parts by weight of a phenol novolak resin having a softening point of 90 ° C. and a hydroxyl equivalent of 103 [Sumitomo Durez Co., Ltd., PR-51714], and 2.8 of TPPK-BA as a curing accelerator. Parts by weight were dry blended, and the gel time of the mixture was measured.
27 seconds at 175 ° C., 52 seconds at 160 ° C.
Seconds. When the activation energy of the gelation reaction was calculated from the gelation time, it was 18.9 kcal / mol. Examples 2-3 Instead of 2.8 parts by weight of curing accelerator TPPK-BA, 3.5 parts by weight of TPPK-NA or TP as a curing accelerator
Except for using 3.0 parts by weight of PK-NO, the same operation as in Example 1 was repeated. Table 1 shows the obtained results. Comparative Examples 1 to 5 The same operation as in Example 1 was repeated except that the curing accelerator of the type and amount shown in Table 1 was used instead of 2.8 parts by weight of the curing accelerator TPPK-BA. The obtained result is
It is shown in the table. Comparative Example 6 Orthocresol novolak epoxy resin having a softening point of 65 ° C. and an epoxy equivalent of 210 [Nippon Kayaku Co., Ltd., EOC
N-125-65], 67 parts by weight, a phenol novolak resin having a softening point of 90 ° C. and a hydroxyl equivalent of 103 [Sumitomo Durez Co., Ltd., PR-51714], 15 parts by weight, and tetraphenylphosphonium tetraphenylborate as a curing accelerator. PR-51714 at 230 ° C at a weight ratio of 1: 9
When 20 parts by weight of the mixture melt-blended were dry-blended, and the gel time of the mixture was measured,
The time was 57 seconds at 175 ° C. and 129 seconds at 160 ° C. When the activation energy of the gelation reaction was calculated from the gelation time, it was 20.2 kcal / mol.

[0013]

[Table 1]

The latent catalysts of Examples 1 to 3 and Comparative Examples 1 to
The amount of the curing accelerator of No. 6 is about 1 which is a normal molding condition.
At 75 ° C., the gelation time was adjusted to be almost the same. The formulations to which TPP, DBU and 2MZ of Comparative Examples 1 to 3 were added all had an activation energy value of the gelation reaction of about 12 to 14 kcal / mol, while the TPPK- BA, TPPK-N
Formulations to which A and TPPK-NO were added, Comparative Examples 4 to 6
TPP-TBB, TPP-BTPB and TPP-K /
Since the formulation to which PN was added showed a larger activation energy of the gelation reaction of 17 to 20 kcal / mol, TPPK-BA, TPPK-NA and TPP
K-NO was found to show greater temperature dependence as compared to TPP, DBU and 2MZ. That is, the formulation to which the latent catalyst used in Examples 1 to 3 was added,
When the gelation time at 175 ° C. is set to a constant value, the reaction rate at room temperature becomes slow, suggesting that good storage stability is exhibited. Example 4 Biphenyl type epoxy resin having a melting point of 105 ° C. and an epoxy equivalent of 185 [Yuka-Shell Epoxy Co., Ltd., YX-4000]
H] 51.7 parts by weight, having a softening point of 95 ° C. and a hydroxyl equivalent of 17
7 para-xylene phenolic resin [Mitsui Toatsu Chemicals
XL-225-3L] 48.3 parts by weight, 4.8 parts by weight of TPPK-BA as a latent catalyst, 3.4 parts of wax
Parts by weight and 397 parts by weight of spherical silica were dry-blended, and the stabilization time was measured using 60 g of the mixture.
The stabilization time at 90 ° C. is more than 60 minutes and 175
Stabilization time at 79 ° C. was 79 seconds. Examples 5 to 6 Instead of 4.8 parts by weight of the latent catalyst TPPK-BA, 6.2 parts by weight of TPPK-NA or TP as the latent catalyst was used.
Except for using 3.4 parts by weight of PK-NO, the same operation as in Example 4 was repeated. Table 2 shows the obtained results. Comparative Example 7 Biphenyl-type epoxy resin having a melting point of 105 ° C. and an epoxy equivalent of 185 [Yuka Shell Epoxy Co., Ltd., YX-4000]
H] 51.7 parts by weight, having a softening point of 95 ° C. and a hydroxyl equivalent of 17
7 para-xylene phenolic resin [Mitsui Toatsu Chemicals
Ltd., XL-225-3L] 48.3 parts by weight, 1.4 parts by weight of triphenylphosphine as a curing accelerator, 3.4 parts by weight of wax and 397 parts by weight of spherical silica are dry-blended, and 60 g of a mixture is used. And the stabilization time was measured. The stabilization time at 90 ° C. is 12 minutes and 175
Stabilization time at 60 ° C was 60 seconds. Comparative Examples 8 to 11 The same operation as in Example 4 was repeated, except that the type and amount of the curing accelerator shown in Table 2 were used instead of 4.8 parts by weight of the curing accelerator TPPK-BA. The obtained result is
It is shown in the table. Comparative Example 12 Biphenyl-type epoxy resin having a melting point of 105 ° C. and an epoxy equivalent of 185 [Yuka-Shell Epoxy Co., Ltd., YX-4000]
H] 51.7 parts by weight, having a softening point of 95 ° C. and a hydroxyl equivalent of 17
7 para-xylene phenolic resin [Mitsui Toatsu Chemicals
XL-225-3L] 16.5 parts by weight, a curing accelerator of tetraphenylphosphonium tetraphenylborate and XL-225-3L at a weight ratio of 1: 9 at 230 ° C.
35.2 parts by weight melt-blended in, dry-blended 3.4 parts by weight of wax and 397 parts by weight of spherical silica,
When the stabilization time was measured using 60 g of the mixture, the stabilization time at 90 ° C. was 8 minutes, and 175 ° C.
Was 45 seconds.

[0015]

[Table 2]

The formulations of Examples 4 to 6 were all 90 ° C.
Has a very long stabilization time, indicating good storage stability at room temperature. The stabilization time at 90 ° C. of the blends of Comparative Examples 7 to 9 and Comparative Example 12 is as short as about 10 minutes, and is hardened even when heat-mixed to make the components uniform during the materialization of the molding material. This suggests that the reaction has progressed and the storage stability at room temperature is poor. Comparative Examples 10
Formulation No. 11 has a longer stabilization time at 90 ° C. than the formulations of Comparative Examples 7 to 9 and Comparative Example 12, but a stabilization time at 90 ° C. as compared to the formulations of Examples 4 to 6. It is short, suggesting that the storage stability at room temperature is inferior. At 175 ° C. corresponding to the molding temperature, Examples 4 to
The stabilization time of the formulation of No. 6 was within 2 minutes, and Comparative Examples 7 to
9 and Comparative Example 12 had a stabilization time of about 1 minute, and Comparative Examples 10 to 11 had a stabilization time of about 2 minutes or less. It is. From the above results, T used in Examples 4 to 6 was used.
PPK-BA, TPPK-NA and TPPK-NO are
It has been found that it has ideal properties as a latent catalyst. Example 7 Orthocresol novolak type epoxy resin having a softening point of 65 ° C. and an epoxy equivalent of 210 [Nippon Kayaku Co., Ltd., EOC
N-125-65], 67 parts by weight, 33 parts by weight of a phenol novolak resin having a softening point of 90 ° C. and a hydroxyl equivalent of 103 [Sumitomo Durez Co., Ltd., PR-51714], and 2.8 of TPPK-BA as a latent catalyst. Parts by weight dry blended, melted once at 90 ° C, then cooled and pulverized,
When the calorific value of the cured product was measured by DSC, it was 182 mJ / mg. The same measurement was carried out after storing the ground sample at 25 ° C. for 6 months.
At 4 mJ / mg, the storage stability (DSC) at 25 ° C. was 95.6%. Examples 8-9 Instead of 2.8 parts by weight of latent catalyst TPPK-BA, 3.5 parts by weight of TPPK-NA or TP as latent catalyst
Except for using 3.0 parts by weight of PK-NO, the same operation as in Example 7 was repeated. Table 3 shows the obtained results. Comparative Examples 13 to 15 Except that 2.8 parts by weight of the latent catalyst TPPK-BA was used, the same operation as in Example 7 was repeated except that the type and amount of the curing accelerator shown in Table 3 were used. The obtained result is the third
It is shown in the table. Comparative Example 16 Orthocresol novolak type epoxy resin having a softening point of 65 ° C. and an epoxy equivalent of 210 [Nippon Kayaku Co., Ltd., EOC
N-125-65], 67 parts by weight, a phenol novolak resin having a softening point of 90 ° C. and a hydroxyl equivalent of 103 [Sumitomo Durez Co., Ltd., PR-51714], 15 parts by weight, and tetraphenylphosphonium tetraphenylborate as a curing accelerator. PR-51714 at 230 ° C at a weight ratio of 1: 9
20 parts by weight melt-blended in
The storage at 5 ° C. (DSC) was examined. The results are shown in Table 3.

[0017]

[Table 3]

As is clear from the results in Table 3, the TPPK-BA, TPPK-NA and TPPK of Examples 7 to 9 were used.
Each of the formulations to which -NO was added showed a high value of 88% or more in 25 ° C storage stability (DSC),
It can be seen that the curing reaction hardly progressed during the storage for 6 months. In contrast, the formulations of Comparative Examples 13 and 16 had poor storage stability, and the TPP-TBB and TPP-B of Comparative Examples 14 and 15 had poor storage stability.
The formulation containing TPB also has a storage stability (DSC) at 25 ° C of 60.
%, Which indicates that the latency is insufficient from the viewpoint of storage at room temperature. Example 10 Orthocresol novolak type epoxy resin having a softening point of 65 ° C. and an epoxy equivalent of 210 [Nippon Kayaku Co., Ltd., EOCN
-1025-65] 67 parts by weight, 33 parts by weight of a phenol novolak resin having a softening point of 105 ° C. and a hydroxyl equivalent of 104 [Sumitomo Durez Co., Ltd., PR-51470], 2.9 parts by weight of TPPK-BA as a latent catalyst , Fused silica 30
0 parts by weight and 2 parts by weight of carnauba wax were mixed and kneaded with a hot roll at 90 ° C. for 8 minutes to obtain a molding material. The spiral flow of this molding material is 78 cm and the curing torque is 80
kgf-cm. The storage stability at 30 ° C. was 95%. Example 11 The same operation as in Example 10 was repeated, except that 2.9 parts by weight of the latent catalyst TPPK-BA of Example 10 was used and 4.3 parts by weight of TPPK-NA was used as the latent catalyst. The spiral flow of the obtained material was 69 cm, and the curing torque was 76 kgf-cm. The storage stability at 30 ° C. was 97%. Example 12 The same operation as in Example 10 was repeated, except that 2.9 parts by weight of the latent catalyst TPPK-BA of Example 10 was used and 4.3 parts by weight of TPPK-SA was used as the latent catalyst. The resulting material had a spiral flow of 75 cm and a curing torque of 73 kgf-cm. The storage stability at 30 ° C. was 95%. Example 13 The same operation as in Example 10 was repeated, except that 2.6 parts by weight of TPPK-Ph was used as a latent catalyst instead of 2.9 parts by weight of the latent catalyst of Example 10 TPPK-BA. The resulting material had a spiral flow of 72 cm and a curing torque of 77 kgf-cm. The storage stability at 30 ° C. was 89%. Example 14 Instead of 2.9 parts by weight of the latent catalyst TPPK-BA of Example 10, 3.3 TPPK-ICA was used as the latent catalyst.
Except for using parts by weight, the same operation as in Example 10 was repeated. The spiral flow of the obtained material is 74 cm,
The curing torque was 73 kgf-cm. The storage stability at 30 ° C. was 93%. Example 15 The same operation as in Example 10 was repeated except that 2.7 parts by weight of TPPK-BZ was used as the latent catalyst instead of 2.9 parts by weight of the latent catalyst TPPK-BA of Example 10. The spiral flow of the obtained material was 70 cm, and the curing torque was 70 kgf-cm. The storage stability at 30 ° C. was 91%. Comparative Example 17 Example 10 was repeated except that instead of 2.9 parts by weight of the latent catalyst TPPK-BA of Example 10, 0.8 parts by weight of triphenylphosphine (TPP) was used as a curing accelerator.
The exact same operation was repeated. The resulting material had a spiral flow of 70 cm and a curing torque of 74 kgf-cm.
The storage stability at 30 ° C. was 56%. When triphenylphosphine is used as a curing accelerator, storage stability is not good. Comparative Example 18 Instead of 33 parts by weight of the phenol novolak resin of Example 10 and 2.9 parts by weight of the latent catalyst TPPK-BA, 31.1 parts by weight of the phenol novolak resin and 30% by weight of a phenol novolak as a curing accelerator were used. A material was produced in the same manner as in Example 10, except that 2.7 parts by weight of the resin [San Apro Co., Ltd., SA841] was used.
The spiral flow of this material is 73cm and the curing torque is 7
It was 0 kgf-cm. The storage stability at 30 ° C. was 53%. When DBU is used as a curing accelerator, storage stability is not good. Comparative Example 19 Instead of using 67 parts by weight of the ortho-cresol novolac type epoxy resin and 33 parts by weight of the phenol novolak resin of Example 10, except that 30 parts by weight of the ortho-cresol novolak type epoxy resin and 70 parts by weight of the phenol novolak resin were used. It was made into a material by the same operation as in Example 10. An attempt was made to measure the spiral flow of this material, but the measurement was impossible due to poor curing. This material has an equivalent ratio of the epoxy group to the phenolic hydroxyl group of 4.7, and has poor curing due to too many hydroxyl groups. Comparative Example 20 The same operation as in Example 10 was repeated except that 30 parts by weight of TPPK-BA was used as a latent catalyst instead of 2.9 parts by weight of the latent catalyst TPPK-BA of Example 10, but curing was performed. The amount of the accelerator was large and the curing was too fast to form. Comparative Example 21 The same operation as in Example 10 was repeated except that 2500 parts by weight of fused silica was used instead of 300 parts by weight of fused silica in Example 1, but the amount of fused silica as an inorganic filler was too large. Had almost no fluidity and could not be molded. Table 4 summarizes the results of Examples 10 to 16 and Comparative Examples 17 to 21.

[0019]

[Table 4]

[0020]

[Table 5]

[Note] 1) Phenol novolak resin containing 30% by weight of DBU [San Apro Co., Ltd., SA841] Example 16 Melting point of 105 ° C. represented by the formula [4], epoxy equivalent of 195
64.5 parts by weight of a biphenyl type epoxy resin,

Embedded image 35.5 parts by weight of a phenol novolak resin having a softening point of 80 ° C. and a hydroxyl equivalent of 105 represented by the formula [5],

Embedded image 821 parts by weight of spherical silica (average particle size 15 μm), melting point 2
3.7 parts by weight of a 12 ° C latent catalyst TPPK-BA, 1.9 parts by weight of carbon black, 2.8 parts by weight of carnauba wax, 1.9 parts by weight of a brominated phenol novolak type epoxy resin having an epoxy equivalent of 275, 3.7 antimony oxide
The parts by weight were mixed at room temperature with a mixer, then kneaded at 100 ° C. with a biaxial roll, cooled and pulverized to obtain a molding material. The spiral flow of the obtained molding material is 95 cm, 175 ° C.
The gelation time was 36 seconds, the storage at 25 ° C was 90%,
The curability was 82 and the solder resistance was 0/8. Examples 17 to 22 and Comparative Examples 22 to 25 In the same manner as in Example 16, a molding material obtained by blending according to the composition shown in Table 5 was evaluated. Example 1
The molten mixture of tetraphenylphosphonium tetraphenylborate used in 9 and Comparative Example 25 is obtained by melting and mixing 20 parts by weight of tetraphenylphosphonium tetraphenylborate with 80 parts by weight of the phenol resin of the formula [8]. Table 5 shows the evaluation results.

[0022]

[Table 6]

[0023]

[Table 7]

[Note] 1) Melt mixture of tetraphenylphosphonium tetraphenylborate

Embedded image (Melting point 80 ° C, epoxy equivalent 190)

Embedded image (Melting point 51 ° C, epoxy equivalent 150)

Embedded image (Melting point: 73 ° C., hydroxyl equivalent: 175) The materials comprising the compositions of the present invention of Examples 16 to 22 all have good fluidity immediately after production, and have a flowability of 1 at 25 ° C.
After storage for one week, all but one case are 90
It has a spiral flow value of at least% and is excellent in storage stability. The gelation time at 175 ° C. is in the range of 18 to 52 seconds, the molding workability is good, and the shore D hardness reaches 82 to 88 by curing. In the solder resistance test,
No cracks occurred. On the other hand, the material of Comparative Example 22 had poor soldering resistance due to a small amount of the fused silica as the inorganic filler, and cracks occurred in all eight samples tested. The material of Comparative Example 23 has poor fluidity because the amount of spherical silica as an inorganic filler is too large. The material of Comparative Example 24 containing tetraphenylphosphonium tetraphenylborate (TPP-K) as a curing accelerator did not cure at all even by heating for 2 minutes. In the material of Comparative Example 25 using a molten mixture of tetraphenylphosphonium tetraphenylborate as a curing accelerator, the spiral flow value after storage at 25 ° C. for one week was reduced to 71% of the value immediately after production, and the storage stability was low. Was bad.

[0025]

The latent catalyst of the present invention can stably store a resin composition for a long period of time without exhibiting a catalytic action at normal temperature, and exhibits an excellent catalytic action when heated during molding. To give good moldability and high quality molded products. The epoxy resin composition containing the latent catalyst of the present invention is particularly useful for electronic and electric parts.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C08L 63/00 C08L 63/00 C 79/08 79/08 Z (72) Inventor Ken Ota 2-5 Higashishinagawa, Shinagawa-ku, Tokyo No. 8 Sumitomo Bakelite Co., Ltd. (56) References JP-A-49-118797 (JP, A) JP-A-50-71799 (JP, A) JP-A-61-204954 (JP, A) JP-A-4-183711 (JP, A) JP-A-4-351629 (JP, A) JP-A-7-330787 (JP, A) JP-A-8-196911 (JP, A) JP-B 5-76490 (JP, A) B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08G 59/40 C08G 59/68 C08G 73/12 B01J 31/24 C08L 63/00-63/10 C08L 79/08 C08K 5/55

Claims (15)

(57) [Claims] 1. A latent catalyst comprising a phosphonium borate represented by the general formula [1]. Embedded image (However, in the formula, R ¹ , R ² , R ³ and R ⁴ are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring, and they are different even if they are the same. Y ¹ , Y ² , Y ³ and Y ⁴ are a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocyclic ring,
At least one of them is a group in which a proton donor having at least one proton that can be released outside the molecule releases one proton, and they may be the same or different from each other . ) 2. The latent catalyst according to claim 1, wherein the proton donor is a carboxylic acid having at least one carboxyl group in one molecule. 3. The latent catalyst according to claim 2, wherein the carboxylic acid is an aromatic carboxylic acid. 4. The latent catalyst according to claim 1, wherein the proton donor is a phenolic compound having at least one hydroxyl group in one molecule. 5. The latent catalyst according to claim 1, wherein the proton donor is isocyanuric acid. 6. The latent catalyst according to claim 1, wherein the proton donor is benzotriazole. 7. A thermosetting resin in an amount of 100 parts by weight.
6. A thermosetting resin composition comprising 0.4 to 20 parts by weight of the latent catalyst according to 6. 8. The thermosetting resin composition according to claim 7, wherein the thermosetting resin is at least one resin selected from the group consisting of an epoxy resin and a maleimide resin. 9. The thermosetting resin composition according to claim 8, wherein the thermosetting resin composition further contains an oxirane-reactive curing agent. 10. The oxirane-reactive curing agent comprises a diamine,
The thermosetting resin composition according to claim 9, which is at least one compound selected from the group consisting of polyamines, acid anhydrides, and phenolic compounds. 11. The thermosetting resin composition according to claim 8, wherein the maleimide resin is a resin containing alkenylphenol. 12. An epoxy resin having (A) two or more epoxy groups in one molecule, (B) a phenol resin having two or more phenolic hydroxyl groups in one molecule, (C).
7. A latent catalyst according to any one of claims 1 to 6, further comprising (D) an inorganic filler, an epoxy group of the epoxy resin (A) and a phenol resin.
The equivalent ratio of the phenolic hydroxyl group of (B) is 0.5 to 2, and the content of the latent catalyst (C) is 0.4 to 20 parts by weight per 100 parts by weight of the total amount of the epoxy resin and the phenol resin. Yes, the content of the inorganic filler (D) is 200 to 2 per 100 parts by weight of the total amount of the epoxy resin and the phenol resin.
A thermosetting resin composition, which is 400 parts by weight. 13. An epoxy resin (A) having a melting point of 50 to 150.
The thermosetting resin composition according to claim 12, which is a crystalline epoxy resin at a temperature of ° C. 14. The content of the inorganic filler (D) is 250 parts per 100 parts by weight of the total amount of the epoxy resin and the phenol resin.
14. The thermosetting resin composition according to claim 12, wherein the amount is from 1 to 1400 parts by weight. 15. The crystalline epoxy resin is a compound represented by the general formula [2] or [3].
5. The thermosetting resin composition according to 4. Embedded image (Wherein, R ⁵ is hydrogen or a methyl group.) (Wherein, R ⁶ is hydrogen or a methyl group.)