JPH09328535A - Latent catalyst and thermosetting resin composition containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a catalyst which does not exhibit catalytic activity at normal temp., enabling a thermosetting resin compsn. to be stored stably for a long term, and exhibits an excellent catalytic activity when heated during molding by selecting a specific phosphonium borate compd. as the catalyst. SOLUTION: This catalyst is a phosphonium borate compd. represented by formula I (wherein R<1> to R<4> are each a monovalent org. group having an arom. or heterocyclic ring or a monovalent aliph. group; and Y<1> to Y<4> are each R<1> provided at least one of them is a group formed by removing a proton from a proton donor selected from among an arom. polycarboxylic acid, an arom. carboxylic acid having at least one acid anhydride group and at least one carboxyl group, a polyphenol compd., and an arom. compd. having at least one carboxyl group and at least one phenolic hydroxyl group) (e.g. a compd. represented by formula II). A thermosetting resin compsn. is prepd. by incorporating the catalyst into a thermosetting resin (pref. an epoxy resin and/or a maleimide resin).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a latent catalyst and a thermosetting resin composition containing the catalyst. More specifically, the present invention can mix various thermosetting resins, particularly epoxy resins and maleimide resins, and stably store the resin composition for a long period of time without exhibiting a catalytic action at room temperature. A latent catalyst which is capable of exerting an excellent catalytic action when heated at the time of molding and can give a molded product having good moldability and high quality, and particularly an electronic / electrical component comprising the latent catalyst. The present invention relates to a thermosetting resin composition which is useful for use.

[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 an epoxy resin, amines (JP-A-58-173852), imidazole compounds (JP-A-56-160056, JP-A-57-59365, JP-A-57-59365) are used as curing catalysts. 57-100128), diazabicycloundecene (JP-A-56-94).
761 and JP-A-59-75923), nitrogen-containing heterocyclic compounds, organosilicon compounds (JP-A-56-133855), organophosphine compounds (JP-A-56-130953). , JP-A-57-2329), quaternary ammonium, phosphonium or arsonium compounds (JP-A-55-1).
53358, JP-A-57-194555,
Various compounds such as JP-A-58-119656) are used. 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. As a curing catalyst for the maleimide-based resin, an azo compound, a radical polymerization initiator such as an organic peroxide (JP-A-5-51418), amines, an imidazole-based compound (JP-A-4-351629), an organo Various compounds such as phosphine compounds (JP-A-61-233017, JP-A-1-45426), ion catalysts such as quaternary ammonium or phosphonium compounds are used.

Generally used catalysts often exhibit a curing acceleration effect even at a relatively low temperature such as room temperature.
For example, in order to accelerate the curing reaction of the resin by heating or heat generation when mixing the resin and other compounding ingredients, and to promote the curing reaction even after the resin composition is stored at room temperature after mixing, the resin composition Quality, in particular, an increase in melt viscosity and a variation in curability due to a decrease in fluidity are liable to occur, which is a cause of molding problems and deterioration of mechanical, electrical and chemical properties of a molded product. Therefore, when using such a catalyst, strict quality control at the time of mixing with various components,
In addition, it is inevitable to keep it at a low temperature for storage and transportation and to strictly control molding conditions. Therefore, in recent years, many studies have been conducted to develop a so-called latent catalyst that does not progress the curing reaction of the resin at a relatively low temperature such as room temperature and promotes the curing reaction only when heated during molding. One of them is a latent catalyst that ionizes the active site of the catalyst and caps it with a protecting group. For example, Japanese Patent Publication No. 51-24399 discloses that
It is described that tetraphenylphosphonium tetraphenylborate (hereinafter referred to as TPP-K) is effective in improving the room temperature storage stability and curability. However, TPP
-K has a strong ionic bond between a cationic tetraphenylphosphonium group and an anionic tetraphenylborate group, has a melting point of 300 ° C or higher, and cannot be uniformly dispersed even when kneaded into a thermosetting resin composition. However, the catalytic activity becomes low, and good curing reactivity cannot be exhibited during molding.

A ionic bond between an anion part and a cation part has a moderate strength, and it exhibits a preferable behavior as a latent catalyst, and a catalyst which can be dry blended with a thermosetting resin has been studied, and it is disclosed in Japanese Patent Publication No. 5-76490. Proposed a tetra-substituted phosphonium tetra-substituted borate as a latent catalyst. The boron-side substituent 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. In any case, the tetra-substituted borate group, which is a protecting group, is removed during the curing reaction during molding,
Although the active sites of the catalyst are exposed and the curing reaction proceeds, the tetra-substituted borate group, which is this protecting group, is decomposed by the high temperature during the curing reaction. Although this decomposed product varies depending on the substituents on the boron side, it may be dispersed in the cured product as a substance different from the matrix, or in some cases generated as a volatile component, and thus the final cured product of the thermosetting resin composition. It may adversely affect the characteristics.

On the other hand, as a promising field in which the thermosetting resin composition is used, there is a sealing material for semiconductor elements such as IC and LSI and electric parts. Conventionally, epoxy resin compositions have been widely used from the viewpoint of characteristics and cost balance. In such an epoxy resin encapsulant, conventionally used curing accelerators are 2-methylimidazole, 1,8-diazabicyclo [5.4.0] undecene-7, triphenylphosphine, etc. As described above, the curing accelerators have a curing-accelerating effect even at a relatively low temperature, so the epoxy resin encapsulants using these have poor storage stability at room temperature, and therefore, storage at room temperature reduces fluidity during molding. From the filling failure, I
The gold wire of the C chip is broken, which causes problems such as poor conduction. For this reason, the epoxy resin encapsulant needs to be refrigerated and transported under refrigeration, and the present situation is that storage and transportation are very costly.

Further, 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 a package is mounted. In order to improve this solder resistance, resin compositions containing a large amount of inorganic filler have been developed. As a method for enabling the blending of a large amount of inorganic filler, there are selection of particle size distribution and shape of the inorganic filler, and reduction of viscosity of the epoxy resin. However, if the molecular weight of the resin is reduced to reduce the viscosity of the resin, the molecules move easily and the crosslinking reaction proceeds rapidly in the initial stage of the reaction. Does not appear, and for the same reason, the reaction is likely to occur even at room temperature, and thus there is a drawback that the storage stability at room temperature of the resin composition decreases. Further, a resin having a low molecular weight has a high initial reactivity, but in the final stage of the reaction, on the contrary, there is a problem that the crosslinking density is not sufficiently increased and the sealing resin is not sufficiently cured. The requirements for the final cured product properties of such semiconductor encapsulation materials are particularly strict, and higher quality is desired.

[0007]

The present invention is capable of stably storing a resin composition for a long period of time without exhibiting a catalytic action at room temperature, and exhibits an excellent catalytic action when heated during molding. A latent catalyst capable of giving a good curability and a high-quality molded article, and
The purpose of the present invention is to provide a thermosetting resin composition containing the latent catalyst, which is particularly useful for electronic and electric parts.

[0008]

As a result of intensive studies to solve the above problems, the present inventors have found that when a tetra-substituted phosphonium tetra-substituted borate having a specific structure is blended with a thermosetting resin. , Shows excellent storage stability at room temperature, and shows excellent curability during heat molding,
Moreover, they have found that the final cured product has physical properties that are not inferior to those obtained when a conventionally used catalyst is used, and the present invention has been completed based on this finding.

That is, the present invention provides (1) general formula [1]
A latent catalyst consisting of phosphonium borate,

Embedded image (In the formula, R ¹ , R ² , R ³ and R ⁴ are monovalent organic groups or monovalent aliphatic groups having an aromatic ring or a heterocycle, and they may be the same or different. Y ¹ , Y ² , Y ³ and Y ⁴ are each a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocycle,
At least one of them is an aromatic polycarboxylic acid having two or more carboxyl groups in the molecule, an aromatic carboxylic acid having at least one acid anhydride group and one carboxyl group in the molecule, A proton donor selected from the group consisting of a polyhydric phenol compound having two or more hydroxyl groups in one molecule and an aromatic compound having at least one carboxyl group and one phenolic hydroxyl group in one molecule has one proton. These groups are released groups, and they may be the same or different from each other. )

(2) A thermosetting resin composition comprising 100 parts by weight of a thermosetting resin and 0.4 to 20 parts by weight of the latent catalyst according to claim 1, (3) a thermosetting composition The thermosetting resin composition according to claim 2, wherein the resin is one or more resins selected from the group consisting of epoxy resins and maleimide resins, and (4) the thermosetting resin composition further comprises an oxirane reaction. A thermosetting resin composition according to claim 3 containing a hydrophilic curing agent, and (5) the oxirane-reactive curing agent is one or more selected from the group consisting of diamines, polyamines, acid anhydrides and phenolic compounds. The thermosetting resin composition according to claim 4, which is a compound, and (6) the maleimide resin is a resin containing alkenylphenol. The thermosetting resin composition according to claim 3, (7) (A) 1 Two epoxy groups in the molecule Epoxy resin having the above, (B) 1
A phenolic resin having two or more phenolic hydroxyl groups in the molecule, (C) the latent catalyst according to claim 1, and (D)
It contains an inorganic filler, the equivalent ratio of the epoxy groups of the epoxy resin (A) and the phenolic hydroxyl group of the phenol resin (B) is 0.5 to 2, and the content of the latent catalyst (C) is epoxy resin. And the total amount of the phenol resin is 0.4 to 20 parts by weight per 100 parts 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. (8) Epoxy resin (A), which is a thermosetting resin composition
Is a crystalline epoxy resin having a melting point of 50 to 150 ° C., and the thermosetting resin composition according to claim 7, wherein the content of the inorganic filler (D) is (9) the total amount of the epoxy resin and the phenol resin is 100 wt. The thermosetting resin composition according to claim 7 or 8, wherein the crystalline epoxy resin (10) is 250 to 1400 parts by weight per part by the general formula [2], the general formula [3] or the general formula [4]. The thermosetting resin composition according to claim 8 or 9, which is a compound shown.

[0011]

[Chemical 6] (In the formula, R ⁵ is a group or atom selected from hydrogen, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen, and they are the same or different. May be.)

[0012]

[Chemical 7] (In the formula, R ⁶ is a group or atom selected from hydrogen, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen, and they may be the same or different. May be.)

[0013]

Embedded image (In the formula, R ⁷ is a group or atom selected from hydrogen, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen, and they may be the same or different. May be provided).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The latent catalyst of the present invention comprises 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 monovalent organic groups having an aromatic ring or a heterocycle or monovalent aliphatic groups, They may be the same or different from each other. Examples of such phosphonium group include, for example, tetraphenylphosphonium group, tetratolylphosphonium group, tetraethylphenylphosphonium group, tetramethoxyphenylphosphonium group, tetranaphthylphosphonium group,
Tetrabenzylphosphonium group, ethyltriphenylphosphonium group, n-butyltriphenylphosphonium group, 2-hydroxyethyltriphenylphosphonium group, trimethylphenylphosphonium group, methyldiethylphenylphosphonium group, methyldiallylphenylphosphonium group, tetra-n-butyl Examples thereof include a phosphonium 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, From the viewpoint of uniform dispersion, it is preferably 250 ° C or lower. In particular, phosphonium borate having a tetraphenylphosphonium group has good compatibility with a thermosetting resin and can be preferably used.

In the general formula [1], the borate groups 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 an aromatic polycarboxylic acid having two or more carboxyl groups in the molecule, one aromatic carboxylic acid having at least one acid anhydride group and one carboxyl group in one molecule, and one molecule. A proton donor selected from the group consisting of a polyhydric phenol compound having two or more hydroxyl groups in the molecule and an aromatic compound having at least one carboxyl group and one phenolic hydroxyl group in one molecule releases one proton. And groups which are the same or different from each other. Examples of the proton donor that provides such a borate group include aromatic compounds such as terephthalic acid, naphthalenedicarboxylic acid, 4,4-biphenyldicarboxylic acid, 4,4′-dicarboxydiphenylmethane, trimellitic acid and pyromellitic acid. Polycarboxylic acid, acid anhydride group-containing aromatic carboxylic acid such as trimellitic anhydride, hydroquinone, catechol, resorcin, dihydroxynaphthalene, 4,4-biphenol,
4,4'-dihydroxydiphenylmethane, 2,2-bis (4-hydroxyphenyl) propane, 4,4'-dihydroxydiphenyl-2,2-hexafluoropropane, bis (3,5-dimethyl-4-dihydroxyphenyl) Polyhydric phenol compounds such as methane, bis (3,5-dimethyl-4-dihydroxyphenyl) sulfone, 4,4-dihydroxystilbene, 4,4-dihydroxy-α-methylstilbene and bisphenolfluorene,
Examples thereof include compounds such as salicylic acid, hydroxybenzoic acid, and hydroxynaphthoic acid, but are not limited thereto.

The latent catalyst comprising phosphonium borate represented by the general formula [1] of the present invention does not show catalytic activity at room temperature when blended with a thermosetting resin, so that the curing reaction of the thermosetting resin is It does not proceed and the catalytic activity is expressed at a high temperature during molding, and once expressed, the catalytic activity is stronger than that of a conventional curing accelerator and the curing degree of the thermosetting resin is increased. The latent catalyst composed of phosphonium borate represented by the general formula [1] of the present invention has an anionic tetra-substituted borate group as a protective group at room temperature, and a cationic tetra-substituted phosphonium group serving as an active site and an ion. Cap by forming a bond. Further, the protective group does not come off even by heating or heat generation when mixing the thermosetting resin and other 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, but TPP-K has too strong an ionic bond. Therefore, the melting point is 300 ° C. or higher, the resin composition cannot be uniformly dispersed even when kneaded, and the effect as a curing accelerator cannot be sufficiently exhibited. Therefore, a structure in which the binding force between the tetraphenylphosphonium group and its protective group is appropriately weakened 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.

Further, in the latent catalyst of the present invention, the energy required for dissociating the cationic tetra-substituted phosphonium group and the anionic tetra-substituted borate group is obtained by mixing the thermosetting resin with other compounding ingredients. Since it cannot be obtained by heating or heat generation at the time, the protecting group is not removed and the reactivity at low temperature 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 because of less reaction during kneading, and achieve high reactivity when heated to a high temperature. In the latent catalyst of the present invention, when the protective group is removed during molding, a protective group decomposition product is generated. This protective group decomposition product has at least two effective functional groups in the molecule. At the same time, it reacts with the thermosetting resin that is the matrix and is incorporated into the crosslink of the curing, so that it does not adversely affect the properties of the final cured product. The latent catalysts comprising phosphonium borate of the present invention are particularly useful for epoxy resins, especially phenolic resins or epoxy resins containing carboxylic acid anhydride hardeners. Further, the latent catalyst comprising phosphonium borate of the present invention is also useful for maleimide resins, particularly maleimide resins containing alkenylphenols as comonomers.

The thermosetting resin composition of the present invention contains 100 parts by weight of the thermosetting resin and 0.4 to 20 parts by weight of the latent catalyst. The mixing of the thermosetting resin and the latent catalyst is usually carried out at an appropriately high temperature, for example, 70 to 150 ° C, preferably 80.
It can be carried out at ˜110 ° C. If the content of the latent catalyst is less than 0.4 parts by weight per 100 parts by weight of the thermosetting resin, sufficient curability may not be obtained during heat molding. On the other hand, if the amount exceeds 20 parts by weight, the curing may be too fast and the fluidity may decrease during molding, resulting in defective filling. The latent catalyst of the present invention may be used alone or in combination of two or more, and may be used in combination with other curing accelerators within a range not impairing the object of the present invention. It is also possible. The latent catalyst comprising phosphonium borate of the present invention can be used without particular limitation for all thermosetting resins whose thermosetting is accelerated by the latent catalyst. The latent catalysts of the present invention are particularly useful for thermosetting resins where traditionally phosphine or phosphonium salt catalysts have been effective. Examples of such a thermosetting resin include, for example, epoxy resins and maleimide resins, but in addition to these resins, a resin in which the reactive monomer is a cyanate, an isocyanate, or an acrylate, Examples thereof include alkenyl resin and alkynyl resin.

The epoxy resin used in the thermosetting resin composition of the present invention is usually a compound having two or more oxirane rings in one molecule, and has a molecular weight of about 340 to 7,000, ranging from liquid to solid. Up to one can be used. Examples of such epoxy resin include 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 novolac type epoxy resin, Cresol novolac type epoxy resin, cycloaliphatic epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, heterocyclic type epoxy resin, trifunctional type epoxy resin, trishydroxyne phenylmethane type epoxy resin, stilbene type epoxy resin and An epoxy resin obtained by glycidyl etherification of a phenol resin obtained by polymerizing dicyclopentadiene and a phenol by an addition reaction can be mentioned. The maleimide-based resin used in the thermosetting resin composition of the present invention is a resin having at least one maleimide group in its molecule and is not particularly limited, but examples thereof include bismaleimide resin. .

The thermosetting resin composition of the present invention may contain an oxirane-reactive curing agent. The oxirane-reactive curing agent used is not particularly limited, and examples thereof include diamines such as diaminodiphenylmethane, polyamines such as diethylenetriamine, phthalic anhydride, aromatic acid anhydrides such as trimellitic anhydride, and hexahydrophthalic anhydride. Examples thereof include alicyclic acid anhydrides and phenolic compounds such as phenol novolac 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 a latent catalyst and an inorganic filler, the equivalent ratio of the epoxy groups of the epoxy resin and the phenolic hydroxyl group of the phenol resin is 0.5 to 2, and the latent catalyst content is the total amount of the epoxy resin and the phenol resin. It is preferably 0.4 to 20 parts by weight per 100 parts by weight.

1 used in the thermosetting resin composition of the present invention
The phenol resin having two or more phenolic hydroxyl groups in the molecule is not particularly limited, and examples thereof include phenol novolac resin, cresol novolac resin, paraxylylene modified phenol resin, metaxylylene / paraxylylene modified phenol resin, terpene modified phenol resin, dicyclopentadiene. Examples thereof include modified phenolic resin. These phenolic resins can be used without limitation in molecular weight, softening point, hydroxyl group equivalent and the like.
Moreover, these phenol resins can be used individually by 1 type and can also be used even if 2 or more types are mixed. When the thermosetting resin composition of the present invention is used for electronic and electrical parts, it is preferable that the resin has a low chlorine content 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, it is more preferable that the phenol resin is 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 due to the structure in which xylylene and phenol are bonded, the molecule has appropriate flexibility and there is little steric hindrance in the curing reaction. Further, there is little obstruction of the curability, and it is possible to lower the viscosity by reducing the average molecular weight, and even if the average molecular weight is reduced, the curability is less likely to decrease 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. When the equivalent ratio of the epoxy group of the epoxy resin and the phenolic hydroxyl group of the phenol resin is less than 0.5 or exceeds 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 known inorganic fillers can be used. Examples of such inorganic fillers include alumina, fused silica, spherical silica, crystalline silica, secondary agglomerated silica, clay and talc. When the composition of the present invention is used for sealing a semiconductor, the inorganic filler is preferably spherical silica from the viewpoint of improving fluidity. As for the shape of the spherical silica, it is preferable that the shape of the particles themselves be infinitely spherical and the particle size distribution be broad in order to improve fluidity.

In the thermosetting resin composition containing the epoxy resin and the phenol resin of the present invention, it is particularly preferable that the epoxy resin is a crystalline epoxy resin having a melting point of 50 to 150 ° C. Such a crystalline epoxy resin has a molecule having a planar structure such as phenyl, biphenyl, bisphenol, and naphthalene in the main chain and has a relatively low molecular weight, and therefore 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 if a conventional epoxy resin, for example, a low viscosity type of ortho-cresol novolac type epoxy resin is used, the melt viscosity does not decrease sufficiently, and the epoxy resin itself may easily melt at room temperature, which may cause difficulty in molding work. However, these problems 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], a dihydroxydiphenylmethane type epoxy resin represented by the general formula [3] and a stilbene type epoxy resin represented by the general formula [4] are used. It can be used particularly preferably. R ⁵ in the general formula [2], R ⁷ in R ⁶ and the general formula [4] in the general formula [3] is hydrogen, a linear or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, from among halogens Selected groups or atoms, which may be the same or different from each other. In the composition of the present invention,
The epoxy resin represented by the general formula [2], the epoxy resin represented by the general formula [3], and the epoxy resin represented by the general formula [4] can be used alone or in combination of two or more kinds. is there. The melting point of crystalline epoxy resin is 5
When it is 0 ° C. or higher, it does not melt at room temperature and is excellent in workability in the 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 uniformly kneaded in the kneading device.

In the thermosetting resin composition containing the epoxy resin and the phenol resin of the present invention, the content of the inorganic filler is 200 to 2400 parts by weight per 100 parts by weight of the total amount of the epoxy resin and the phenol resin. It is preferable. When 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 by the inorganic filler may not be sufficiently exhibited. If it exceeds 2400 parts by weight, the fluidity of the resin may be lowered, and filling failure may occur during molding. In particular, the content of the inorganic filler is 250 to 140 per 100 parts by weight of the total amount of the epoxy resin and the phenol resin.
When it is 0 part by weight, the water absorption of the resin composition is lowered, and when it is used for semiconductor encapsulation, the solder resistance is improved and the occurrence of cracks can be prevented. Further, the viscosity of the resin composition when melted is low, and there is no possibility of causing gold wire deformation inside the semiconductor package, which is particularly preferable. The latent catalyst of the present invention can be used alone or in a mixture with another curing accelerator. When used as a mixture with another curing accelerator, the latent catalyst of the present invention is preferably 50% by weight or more based on the total amount of the latent catalyst and the other curing accelerator. The latent catalyst of the present invention is 5
If it is less than 0% 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 contains, if necessary, a coloring agent such as carbon black, a brominated epoxy resin, a flame retardant such as antimony trioxide, and γ-glycidoxypropyltrimethoxysilane. Various additives such as a coupling agent, a low-stress component such as silicone oil and rubber, a release agent, an antioxidant, a surface active agent, and a coupling agent can be added. Epoxy resin composition of the present invention, epoxy resin, phenol resin, latent catalyst, inorganic filler, other additives are mixed at room temperature with a mixer, kneaded with a kneader such as a roll, an extruder, and after cooling. It can be crushed into a molding material.

[0028]

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 catalysts and curing accelerators used in the examples and comparative examples are summarized below.

Embedded image

[0029]

Embedded image

[0030]

[Chemical 12]

Evaluation method (1) Spiral flow: Using a mold for spiral flow measurement according to EMMI-I-66, mold temperature 175
It is measured at a temperature of 70 ° C., an injection pressure of 70 kg / cm ² , and a curing time of 2 minutes. The spiral flow is a fluidity parameter, and the larger the value, the better the fluidity. Unit cm. (2) Curing torque: using a curast meter [manufactured by Orientec Co., Ltd., JSR curast meter IVPS type], 1
Determine the torque after 90 seconds at 75 ° C. The torque in the curast meter is a parameter of curability, and the larger the value, the better the curability. The unit is kgf-cm. (3) Storability at 30 ° C .: The material was stored at 30 ° C. for 1 week and then the spiral flow was measured, and expressed as a percentage with respect to the spiral flow immediately after preparation of the material. unit%. (4) Glass transition temperature (hereinafter referred to as Tg): The material was molded at a mold temperature of 175 ° C., a curing time of 2 minutes, and treated at 175 ° C. for 8 hours, and then TMA [manufactured by Seiko Denshi Kogyo KK, 56
At 0 M], the glass transition temperature is measured by the linear expansion method. Unit ° C. (5) Preservability at 25 ° C: After the material was stored at 25 ° C for 1 week, the spiral flow was measured and expressed as a percentage of the spiral flow immediately after preparation of the material. Unit cm. (6) Curability: The material is molded at a mold temperature of 175 ° C. for a curing time of 2 minutes, and after the mold is opened for 10 seconds, the measured Shore D hardness value is defined as the curability. (7) Solder resistance: After treating 8 pieces of 80 pQFP (thickness: 1.5 mm) at 85 ° C. and relative humidity of 85% for 168 hours,
240 ° C IR reflow 240 ° C / 10 seconds treatment 2
The number of package cracks is visually observed, and when the number of cracked packages is n, it is displayed as n / 8.

Example 1 Orthocresol novolac type epoxy resin [Nippon Kayaku Co., Ltd., EOCN-10 25-65, softening point 65 ° C., epoxy equivalent 210] 67 parts by weight Phenol novolac resin [Sumitomo Dures Co., Ltd., PR -51470, softening point 105 [deg.] C., hydroxyl equivalent 104] 33 parts by weight TPPK-TPA 3.5 parts by weight fused silica 300 parts by weight Carnauba wax 2 parts by weight are blended and kneaded at 90 [deg.] C. for 8 minutes for molding. Got the material. Spiral flow, curing torque, storability at 30 ° C. and Tg were measured. The spiral flow of this molding material was 82 cm, and the curing torque was 85 kgf-cm.
Further, the storage stability at 30 ° C. was 93%, and the Tg was 178 ° C. Examples 2 to 4 According to the formulations shown in Table 1, the same operations as in Example 1 were repeated and evaluated in the same manner. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 1 Instead of using 3.5 parts by weight of the catalyst TPPK-TPA of Example 1, 0.8 parts by weight of TPP was used as a catalyst.
The exact same operation as in Example 1 was repeated. The obtained material has a spiral flow of 70 cm and a curing torque of 74 kgf.
−cm. Further, the storage stability at 30 ° C was 56%, and the Tg was 171 ° C. When TPP is used as a catalyst, the storage stability is not good. Comparative Example 2 Instead of 33 parts by weight of the phenol novolac resin of Example 1 and 3.5 parts by weight of the catalyst TPPK-TPA, 31.1 parts by weight of the phenol novolac resin and D as a curing accelerator were used.
Material was prepared in the same manner as in Example 1 except that 2.7 parts by weight of phenol novolac resin [SAN APRO KK, SA841] containing 30% by weight of BU was used. The spiral flow of this material is 73 cm and the curing torque is 70 k.
gf-cm. Also, the storage stability at 30 ° C is 53%,
Tg was 169 ° C. When DBU is used as the curing accelerator, the storage stability is not good.

Comparative Examples 3 and 4 According to the formulations shown in Table 2, the same operation as in Example 1 was repeated and the same evaluation was performed. Table 2 shows the evaluation results. Example 1
All of the materials consisting of the composition of the present invention have good flowability immediately after production, and all have a spiral flow value of 90% or more even after storage for 1 week at 30 ° C., which shows storage stability. Are better. In addition, Tg also shows a high value of 178 ° C. or higher. On the other hand, Comparative Examples 3 and 4
The materials using the catalyst TPPK-NO and the catalyst TPPK-SA of 3 show the same storage stability at 30 ° C. as in Examples 1 to 5, but the Tg shows a low value of 7 to 14 ° C. This is because the decomposition product of the borate anion, which is a protective group for the active site of the catalyst, generated during the curing reaction is a group formed by monofunctional naphthol and stearic acid releasing one proton. It originates in that it reacts with and reduces the crosslink density. In the catalyst of the present invention,
The decomposition product of the borate anion generated during the curing reaction is a group formed by releasing one proton from a compound having two or more oxirane-reactive functional groups, and is incorporated into the crosslink. Therefore, Tg is improved as compared with the case of using the conventional catalyst.

[0035]

[Table 1]

[0036]

[Table 2]

Next, materials having an increased amount of inorganic filler were produced in Examples 6 to 14 and solder resistance was evaluated. Example 6 51.5 parts by weight of biphenyl type epoxy resin of the formula [5] (melting point 105 ° C.)

[0038]

Embedded image

48.5 parts by weight of phenolic resin of the formula [6] (softening point 73 ° C.)

Embedded image

Spherical silica (average particle size 15 μm) 830 parts by weight TPPK-TPA 4.6 parts by weight Carbon black 2 parts by weight Carnauba wax 2.8 parts by weight Brominated phenol novolac type epoxy resin (epoxy equivalent 275) 1.7 parts by weight After being mixed with a mixer at room temperature, the parts were kneaded with a twin-screw roll at 100 ° C., cooled and pulverized to obtain a molding material. The obtained molding material had a spiral flow of 91 cm, a Shore hardness of 84, a 25 ° C. storage stability of 83%, a Tg of 156 ° C., and a solder resistance of 0/8.

Examples 7 to 14 and Comparative Examples 5 and 6 In the same manner as in Example 6, molding compounds were obtained in the same manner as in Example 6 according to the formulations shown in Tables 3 and 4. The evaluation results are shown in Tables 3 and 4, where the formula (7) used in other than Example 6
The structural formulas of formula (8), formula (9) and formula (10) are shown below.

Embedded image (Melting point 80 ° C)

[0042]

Embedded image (Melting point 96 ° C)

[0043]

Embedded image (However, n = 0 is 1, whereas n = 1 is 0.4, n = 2
Of 0.25, softening point 65 ° C, epoxy equivalent 250)

[0044]

Embedded image (However, n = 0 is 1 whereas n = 1 is 0.25, n ≧ 2
Of 0.35, softening point 60 ° C, epoxy equivalent 170)

All the materials made of the compositions of the present invention of Examples 6 to 14 had good fluidity immediately after production, and all had Shore hardness of 80 or more and were stored at 25 ° C. for 1 week. It has a spiral flow value of 83% or more and is excellent in storage stability. In addition, Tg is 153 ° C
The above high values were exhibited, and cracks did not occur at all in the solder resistance test. On the other hand, the materials of Comparative Examples 5 and 6 have the same fluidity and storage stability at 25 ° C. as those of Examples 6 to 14, but the Tg is about 10 ° C. lower. In the solder resistance test, cracks occurred in 1 to 2 of the 8 tested samples.

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

INDUSTRIAL APPLICABILITY The latent catalyst of the present invention can stably store the resin composition for a long period of time without exhibiting catalytic action at room temperature, and exhibits 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.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C08G 59/42 NHY C08G 59/42 NHY 59/50 NJA 59/50 NJA 59/62 NJS 59/62 NJS C08K 3/00 C08K 3/00 C08L 63/00 NKT C08L 63/00 NKT

Claims (10)

[Claims] 1. A latent catalyst comprising phosphonium borate represented by the general formula [1]. Embedded image (In the formula, R ¹ , R ² , R ³ and R ⁴ are monovalent organic groups or monovalent aliphatic groups having an aromatic ring or a heterocycle, and they may be the same or different. Y ¹ , Y ² , Y ³ and Y ⁴ are each a monovalent organic group or a monovalent aliphatic group having an aromatic ring or a heterocycle,
At least one of them is an aromatic polycarboxylic acid having two or more carboxyl groups in the molecule, an aromatic carboxylic acid having at least one acid anhydride group and one carboxyl group in the molecule, A proton donor selected from the group consisting of a polyhydric phenol compound having two or more hydroxyl groups in one molecule and an aromatic compound having at least one carboxyl group and one phenolic hydroxyl group in one molecule has one proton. These groups are released groups, and they may be the same or different from each other. ) 2. A thermosetting resin of 100 parts by weight and claim 1.
A thermosetting resin composition comprising 0.4 to 20 parts by weight of the latent catalyst described above. 3. The thermosetting resin composition according to claim 2, wherein the thermosetting resin is one or more resins selected from the group consisting of epoxy resins and maleimide resins. 4. The thermosetting resin composition according to claim 3, wherein the thermosetting resin composition further contains an oxirane-reactive curing agent. 5. The oxirane reactive curing agent is a diamine,
The thermosetting resin composition according to claim 4, which is one or more compounds selected from the group consisting of polyamines, acid anhydrides, and phenolic compounds. 6. The thermosetting resin composition according to claim 3, wherein the maleimide resin is a resin containing alkenylphenol. 7. (A) Epoxy resin having two or more epoxy groups in one molecule, (B) Phenolic resin having two or more phenolic hydroxyl groups in one molecule, (C).
The latent catalyst described above and (D) an inorganic filler are contained, and the epoxy groups of the epoxy resin (A) and the phenol resin (B) are contained.
Has an equivalent ratio of phenolic hydroxyl groups of 0.5 to 2 and a latent catalyst (C) content of 0.4 to 20 parts by weight per 100 parts by weight of the total amount of the epoxy resin and the phenol resin. The content of the filler (D) is 200 to 24 per 100 parts by weight of the total amount of the epoxy resin and the phenol resin.
A thermosetting resin composition, characterized in that it is 100 parts by weight. 8. The epoxy resin (A) has a melting point of 50 to 15
The thermosetting resin composition according to claim 7, which is a crystalline epoxy resin at 0 ° C. 9. The content of the inorganic filler (D) is 25 per 100 parts by weight of the total amount of the epoxy resin and the phenol resin.
The thermosetting resin composition according to claim 7, which is 0 to 1400 parts by weight. 10. The thermosetting resin composition according to claim 8, wherein the crystalline epoxy resin is a compound represented by the general formula [2], the general formula [3] or the general formula [4]. Embedded image (In the formula, R ⁵ is a group or atom selected from hydrogen, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen, and they are the same or different. May be used.) (In the formula, R ⁶ is a group or atom selected from hydrogen, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen, and they may be the same or different. May be used.) (In the formula, R ⁷ is a group or atom selected from hydrogen, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, and a halogen, and they may be the same or different. May be.)