WO2017150090A1

WO2017150090A1 - Epoxy resin curing accelerator

Info

Publication number: WO2017150090A1
Application number: PCT/JP2017/004336
Authority: WO
Inventors: 礼翼陳
Original assignee: サンアプロ株式会社
Priority date: 2016-02-29
Filing date: 2017-02-07
Publication date: 2017-09-08
Also published as: TW201800439A; JP2017155068A

Abstract

Provided is an epoxy resin curing accelerator having exceptional fluidity during mold filling as well as high catalytic activity and exceptional curability. The present invention is an epoxy resin curing accelerator (Q) characterized by including a phosphonium salt (S) that comprises a quaternary phosphonium (A) represented by general formula (1) and an anion of an organic phenol compound (B) represented by general formula (2), the organic phenol compound (B) represented by general formula (2), and an organic phenol compound (C) represented by general formula (3). [In formula (1), R¹-R³ represent C6-12 aryl groups, and R⁴ represents a C1-8 alkyl group or the like. In formula (2), R⁵-R⁸ are the same or different and each represent hydrogen, a C1-4 alkyl group, or the like, and R⁹ represents a C1-18 alkyl group or the like. In formula (3), R¹⁰ represents hydrogen, a C1-18 alkyl group, or the like, and R¹¹ represents a C6-50 functional group containing a phenol group.]

Description

Epoxy resin curing accelerator

The present invention relates to an epoxy resin curing accelerator. More specifically, the present invention relates to an epoxy resin curing accelerator made of a quaternary phosphonium salt, which is suitable for manufacturing an epoxy resin-based sealing material for electronic parts such as semiconductors.

Conventionally, an epoxy resin is excellent in moldability and electrical properties of a cured product, and is used, for example, as a sealing material for electronic parts such as a semiconductor sealing material. As a sealing material resin, an epoxy resin in which a phenol novolac is used as a curing agent and a large amount of filler is blended is widely used. In recent years, there has been a strong demand for improving the moldability of a sealing material and the reliability of a sealed semiconductor, as the semiconductor is highly integrated, thinned, or improved in mounting method. In response to this demand, the role of a curing accelerator, which is a component of a sealing material, is also increasing.
As a curing accelerator for these epoxy resins, tetraphenylborate salt of tetraphenylphosphonium (hereinafter abbreviated as TPP-K) is generally used.

However, since TPP-K has low catalytic activity as it is, curing does not proceed sufficiently if it is simply blended with an epoxy resin and a curing agent, but it is blended with phenol resin in advance and heated to convert tetraphenylborate salt to phenol resin salt. There is a problem that a small amount of toxic benzene is produced at this time.
As an improvement of this problem, a salt of TPP with an alkyl quaternized phosphonium phenol resin (see Patent Documents 1 and 2) has been proposed.

However, in a sealing material composition containing a high concentration of inorganic filler, when a phenol resin salt of alkyl quaternized phosphonium of TPP is used as a curing accelerator, a mixture of an epoxy resin, a curing agent and a curing accelerator is heated. Since the viscosity of the melted liquid mixture increases, the so-called poor liquid flow property, in which the wiring of the semiconductor chip is swept away during mold filling, or the viscosity increases before the compound reaches every corner, resulting in unfilled parts. Cause.

JP 2004-256663 A JP 2005-162944 A

Therefore, an object of the present invention is to provide an epoxy resin curing accelerator that is excellent in fluidity at the time of mold filling and has high catalytic activity and excellent curability.

The inventors of the present invention have reached the present invention as a result of studies to achieve the above object.
That is, the present invention relates to a phosphonium salt (S) comprising a quaternary phosphonium (A) represented by the general formula (1) and an anion of the organic phenol compound (B) represented by the general formula (2), the general formula ( An epoxy resin curing accelerator (Q) comprising the organic phenol compound (B) represented by 2) and the organic phenol compound (C) represented by the general formula (3).

[In the formula (1), R ¹ to R ³ represent an aryl group having 6 to 12 carbon atoms, and R ⁴ represents an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

[In Formula (2), R ⁵ to R ⁸ are the same or different and each represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or a hydroxyl group, and R ⁹ represents an alkyl group having 1 to 18 carbon atoms, It represents a 6-18 aryl group, a hydroxyalkyl group having 1-18 carbon atoms, a benzyl group, or an allyl group. ]

[In the formula (3), R ¹⁰ represents hydrogen, an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms, and R ¹¹ represents a functional group having 6 to 50 carbon atoms containing a phenol group. ]

Since this invention has quaternary phosphonium (A), hardening of reaction of an epoxy resin and a hardening | curing agent can be accelerated | stimulated.
Moreover, since the anion of the organic phenol compound (B) has an electron-withdrawing ester group, the acid strength of the anion of the organic phenol compound (B) is apparently strong. Further, since the anion of the organic phenol compound (B), the organic phenol compound (B), and the organic phenol compound (C) each have a hydrogen-bondable hydroxyl group, the anion of the organic phenol compound (B) and the organic phenol compound (B) And the interaction between the molecules of the organic phenol compound (C) is strong, the distance between the molecules becomes short, and the anion of the organic phenol compound (B) becomes the organic phenol compound (B) and the organic phenol compound (C ). Thereby, the nucleophilicity of the anion of the organic phenol compound (B) was suppressed. As a result, at the temperature at which the mixture of the epoxy resin, the curing agent and the curing accelerator is heated and melted, the phosphonium salt (S) becomes less active, so that the curing reaction can be suppressed, and the ester structure has flexibility and is mold-filled. Excellent fluidity.
On the other hand, at the curing temperature after mold filling, the hydrogen bond between the anion of the organic phenol compound (B), the organic phenol compound (B) and the organic phenol compound (C) is weakened, and the phosphonium salt (S) is activated, so that the curability is improved. Excellent.

For this reason, the epoxy resin curing accelerator (Q) of the present invention is excellent in fluidity at the time of mold filling, and has high catalytic activity and excellent curability, so it is suitable for production of epoxy resin-based sealing materials for electronic parts such as semiconductors. It is.

The epoxy resin curing accelerator (Q) of the present invention is a phosphonium salt comprising a quaternary phosphonium (A) represented by the general formula (1) and an anion of the organic phenol compound (B) represented by the general formula (2). (S), comprising an organic phenol compound (B) represented by the general formula (2) and an organic phenol compound (C) represented by the general formula (3)

The cation of the quaternary phosphonium (A) is an essential component for promoting the reaction between the epoxy resin and the curing agent, and is represented by the following general formula (1).

Examples of the aryl group having 6 to 12 carbon atoms constituting R ¹ to R ⁴ in the general formula (1) include, for example, phenyl group, naphthyl group, biphenyl group, methylphenyl group, ethylphenyl group, propylphenyl group, butyl A phenyl group, a methyl naphthyl group, an ethyl naphthyl group, etc. are mentioned.

Examples of the alkyl group having 1 to 8 carbon atoms constituting R ⁴ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, t-pentyl group, n-hexyl group, 1-methylpentyl group, 4-methyl-2-pentyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, n -Heptyl group, 1-methylhexyl group, n-octyl group, tert-octyl group, 1-methylheptyl group, 2-ethylhexyl group, 2-propylpentyl group and the like.

R ¹ to R ³ are preferably a phenyl group, a methylphenyl group, and a naphthyl group, and more preferably a phenyl group, from the viewpoint of fluidity after melt-kneading and availability of raw materials.
R ⁴ is preferably an alkyl group having 1 to 4 carbon atoms and an aryl group having 6 to 12 carbon atoms, more preferably a methyl group, an ethyl group and phenyl group from the viewpoints of curability and ease of synthesis. Group, particularly preferably a methyl group or an ethyl group.

The organic phenol compound (B) of the present invention is an essential component for improving fluidity after melt-kneading and curing at the curing temperature after mold filling, and is represented by the following general formula (2).

[In Formula (2), R ⁵ to R ⁸ are the same or different and each represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or a hydroxyl group, and R ⁹ represents an alkyl group having 1 to 18 carbon atoms, An aryl group having 6 to 18 carbon atoms, a hydroxyalkyl group having 1 to 18 carbon atoms, a benzyl group, or an allyl group is represented. ]

Examples of the alkyl group having 1 to 4 carbon atoms constituting R ⁵ to R ⁸ in the general formula (2) include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl. Group, tert-butyl group and the like.

Examples of the alkyl group having 1 to 18 carbon atoms constituting R ⁹ in the general formula (2) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert group. -Butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group and the like.

Examples of the aryl group having 6 to 18 carbon atoms constituting R ⁹ in the general formula (2) include a phenyl group, a naphthyl group, a biphenyl group, a methylphenyl group, an ethylphenyl group, a propylphenyl group, a butylphenyl group, A methyl naphthyl group, an ethyl naphthyl group, etc. are mentioned.

Examples of the hydroxyalkyl group having 1 to 18 carbon atoms constituting R ⁹ in the general formula (2) include a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, and a hydroxybutyl group.

The method for synthesizing the phosphonium salt (S) is not particularly limited. For example, a salt exchange reaction between the alkyl carbonate (A1) of the quaternary phosphonium (A) and the organic phenol compound (B), and a quaternary phosphonium (S It is obtained by a salt exchange reaction between the hydroxide (A2) of A) and the organic phenol compound (B).

The alkyl carbonate (A1) of the quaternary phosphonium (A) can be obtained, for example, by reacting a corresponding tertiary phosphine with a carbonic acid diester. The production conditions are 10 to 200 hours in an autoclave at a temperature of 50 to 150 ° C., and a reaction solvent is preferably used in order to complete the reaction quickly and with a good yield. Although it does not specifically limit as a reaction solvent, Methanol, ethanol, etc. are preferable. The amount of the solvent is not particularly limited.

Examples of the corresponding tertiary phosphine include triphenylphosphine, tris (4-methylphenyl) phosphine, 2- (diphenylphosphino) biphenyl, and the like. The carbonic acid diester is not particularly limited as long as it is a known one, and specifically, diethyl carbonate, dimethyl carbonate, dibutyl carbonate, diphenyl carbonate and the like are used.

The quaternary phosphonium (A) hydroxide (A2) is obtained by, for example, reacting a corresponding tertiary phosphine with a halogenated (bromine or chlorine) alkyl or halogenated (bromine or chlorine) aryl. Later, it is obtained by salt exchange with an inorganic alkali. The production conditions are a temperature of 20 to 150 ° C. and a time of 1 to 20 hours, and a reaction solvent is preferably used in order to complete the reaction quickly and with a good yield. Although it does not specifically limit as a reaction solvent, Methanol, ethanol, etc. are preferable. The amount of the solvent is not particularly limited.

Examples of the corresponding tertiary phosphine include those described above. Examples of the halogenated alkyl include ethyl bromide, butyl chloride, 2-ethylhexyl bromide, 2-butylethanol, 2-chloropropanol and the like, and examples of the halogenated aryl include bromobenzene, bromonaphthalene and bromobiphenyl.
Examples of the inorganic alkali include sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, and aluminum hydroxide.

When the salt exchange reaction between the quaternary phosphonium (A) alkyl carbonate (A1) or hydroxide (A2) and the organic phenol compound (B) is carried out, the production conditions are as follows. While reacting for 20 hours, by-produced alcohol, water, carbon dioxide gas, and reaction solvent are removed if necessary.

As a method for synthesizing a phosphonium salt (S), a salt of an alkyl carbonate (A1) of a quaternary phosphonium (A) and an organic phenol compound (B) from the viewpoint of preventing mixing of ionic impurities that deteriorate electrical reliability. Exchange reactions are preferred.

Furthermore, when the anion comprising the organic phenol compound (B) has an intramolecular hydrogen bond (formula (6)), the nucleophilicity is suppressed, thereby heating the mixture of epoxy resin, curing agent and curing accelerator. At the melting temperature, the phosphonium salt (S) becomes less active so that the curing reaction is suppressed and the fluidity at the time of mold filling is excellent. The organic phenol compound (B) has the following advantages from the viewpoint of curability. Those are preferred.
A: A compound in which R ⁵ is a hydroxyl group, and R ⁶ , R ⁷ , and R ⁸ are the same or different and each is hydrogen or a hydroxyl group.
B: A compound in which R ⁵ is a hydroxyl group, R ⁶ and R ⁷ are hydrogen, and R ⁸ is a hydroxyl group.
C: A compound in which R ⁶ is a hydroxyl group, and R ⁵ , R ⁷ , and R ⁸ are the same or different and each is hydrogen or a hydroxyl group.
D: A compound in which R ⁶ is a hydroxyl group, and R ⁵ , R ⁷ , and R ⁸ are hydrogen.

The organic phenol compound (C) is an essential component for interacting with the anion of the organic phenol compound (B) in the phosphonium salt (S), suppressing the activity during melt kneading and improving fluidity, It is an essential component for improving the curability at the time of sealing, and is represented by the following general formula (3).

Among these, in general formula (3), a compound in which R ¹¹ is represented by general formula (4) is preferably exemplified.

In the general formula ^{(3), the compound R 11} is represented by the general formula (5) may be preferably mentioned.

[In the formula (5), R ¹² and R ¹³ represent hydrogen, an alkyl group having 1 to 38 carbon atoms, and an aryl group having 1 to 38 carbon atoms. ]

The molar ratio of the phosphonium salt (S) and the organic phenol compound (B) is usually 10/90 to 99.9 / 0.1 from the viewpoint of easy interaction with the anion of the phenol (B), preferably Is 20/80 to 80/20, particularly preferably 30/70 to 70/30.

The molar ratio of the phosphonium salt (S) and the organic phenol compound (C) is usually 10/90 to 99.9 / 0.1 from the viewpoint of easy interaction with the anion of the phenol (C), preferably Is 20/80 to 80/20, particularly preferably 30/70 to 70/30.

The epoxy resin curing accelerator (Q) is usually obtained by uniformly mixing a phosphonium salt (S), an organic phenol compound (B), and an organic phenol compound (C) at a temperature of 50 to 200 ° C. for 1 to 20 hours. Can be obtained. A solvent may be used in order to complete the mixing quickly. After uniform mixing, the solvent and the like are removed at a temperature of 50 to 200 ° C. under reduced pressure to normal pressure. The solvent is not particularly limited, but methanol, ethanol and the like are preferable.
The mixing ratio of the phosphonium salt (S) and the organic phenol compound (B) is appropriately determined from the molar ratio of the phosphonium salt (S) and the organic phenol compound (B).
The blending ratio of the phosphonium salt (S) and the organic phenol compound (C) is appropriately determined from the molar ratio of the phosphonium salt (S) and the organic phenol compound (C).

In order to facilitate mixing with the epoxy resin composition, the epoxy resin curing accelerator (Q) includes a method of lowering the softening point by making a masterbatch with a low viscosity phenol resin, a method of pulverizing and powdering, etc. You can go.
Examples of the low viscosity phenol resin include bisphenol A, bisphenol F, phenol novolac resin, cresol novolac resin, and phenol aralkyl resin. A known method can be used as a master batch method.
The softening point of the epoxy resin curing accelerator (Q) is usually 70 to 150 ° C, preferably 80 to 120 ° C, more preferably 90 to 100 ° C. If the temperature is lower than 70 ° C., it is not preferable because fusion during pulverization or block formation during storage of the powdered accelerator is likely to occur, and if it exceeds 150 ° C., the curing accelerator is melted with the epoxy resin. This is because they cannot be mixed and become non-uniform, which tends to cause curing failure.

As a method of pulverizing into a powder, for example, a powdery curing accelerator can be obtained by pulverization with an impact pulverizer or the like. In use, the particle size of the powdery curing accelerator is preferably 100% or more (measured by an air jet sieve method or the like) 95% or more. This is because if it is less than 95%, uniform dissolution in the epoxy resin composition tends to be hindered, which causes poor curing.

The epoxy resin curing accelerator (Q) of the present invention is used by being added to a mixture in which other additives such as an epoxy resin, a curing agent and a filler are blended as required, and finally a cured epoxy resin is obtained. . The compounding amount of the epoxy resin curing accelerator (Q) is adjusted according to the reactivity of the epoxy resin and the curing agent, but is usually 1 to 25 parts by mass, preferably 2 to 20 parts by mass with respect to 100 parts by mass of the epoxy resin. It is. What is necessary is just to set the optimal compounding quantity according to the hardening characteristic etc. which are requested | required.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

<Production Example 1>
<Method for producing quaternary phosphonium base (A-Be1)>
In a stirring autoclave, 180 parts of dimethyl carbonate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 224 parts of methanol as a solvent are charged, and 262 parts of triphenylphosphine (manufactured by Tokyo Chemical Industry Co., Ltd.) are charged therein, and the reaction temperature is increased. The reaction was performed at 125 ° C. for 80 hours. Next, 120 parts of methanol was removed under reduced pressure, and 1200 parts of toluene was added to precipitate crystals. This crystal was isolated and dissolved again in methanol to obtain a solution (solid content concentration 50%) of triphenylmethylphosphonium monomethyl carbonate as a quaternary phosphonium base (A-Be1).

<Production Example 2>
<Method for producing quaternary phosphonium base (A-Be2)>
Instead of 262 parts of triphenylphosphine in Production Example 1, 304 parts of tris (4-methylphenyl) phosphine (manufactured by Tokyo Chemical Industry Co., Ltd.) and diethyl carbonate (manufactured by Tokyo Chemical Industry Co., Ltd.) instead of dimethyl carbonate The quaternary phosphonium base (A-Be2) was used as a quaternary phosphonium base (A-Be2) except that the reaction temperature was 130 ° C. and the reaction time was 150 hours. A solution (solid concentration 50%) was obtained.

<Production Example 3>
<Method for producing quaternary phosphonium base (A-Be3)>
A glass round bottom three-necked flask equipped with a dropping funnel and a reflux tube was charged with 419 parts of tetraphenylphosphonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) and 1000 parts of methanol, and dissolved uniformly, and then 40 parts of sodium hydroxide. Was slowly added and reacted at room temperature for 5 hours, and the precipitated salt was removed to obtain a tetraphenylphosphonium hydroxide solution (solid content concentration 25%) as a quaternary phosphonium base (A-Be3).

<Comparative Production Example 1>
<Method for producing quaternary phosphonium base (A-Be'1)>
In a stirring autoclave, 180 parts of dimethyl carbonate and 224 parts of methanol as a solvent were added, and 202 parts of tributylphosphine was added dropwise thereto, and reacted at a reaction temperature of 125 ° C. for 20 hours to give a quaternary phosphonium base ( A solution of tributylmethylphosphonium monomethyl carbonate (solid content concentration 50%) was obtained as A-Be′1).

<Example 1>
Into a glass round bottom three-necked flask equipped with a dropping funnel and a reflux tube, 704 parts of the quaternary phosphonium base (A-Be1) produced in Production Example 1 was placed, and 4-hydroxybenzoic acid was adjusted while controlling the temperature at 50 ° C. 400 parts of butyl acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was dividedly added, and 305 parts of 1,1,1-tris (4-hydroxyphenyl) ethane (manufactured by Tokyo Chemical Industry Co., Ltd.) were dividedly charged. The temperature was raised to 175 ° C. while distilling off the solvent (methanol), and the remaining solvent was removed under reduced pressure to obtain an epoxy resin curing accelerator (Q-1).
The molar ratio of the phosphonium salt (S), the organic phenol compound (B), and the organic phenol compound (C) in (Q-1) was 1.00 / 1.06 / 1.00.

<Example 2>
Instead of 400 parts of butyl 4-hydroxybenzoate in Example 1, 400 parts of phenyl 4-hydroxybenzoate (manufactured by Tokyo Chemical Industry Co., Ltd.), 305 parts of 1,1,1-tris (4-hydroxyphenyl) ethane Instead, an epoxy resin curing accelerator (Q-2) was used in the same manner as in Example 1 except that 305 parts of 4,4 ′, 4 ″ -trihydroxytriphenylmethane (Tokyo Chemical Industry Co., Ltd.) was changed. Got.
The molar ratio of the phosphonium salt (S), the organic phenol compound (B), and the organic phenol compound (C) in (Q-2) was 1.00 / 0.87 / 1.05.

<Example 3>
Instead of the quaternary phosphonium base (A-Be1) in Example 1, the quaternary phosphonium base (A-Be2) prepared in Preparation Example 2 was used instead of butyl 4-hydroxybenzoate, and 3,4-dihydroxybenzoate was used. An epoxy resin curing accelerator (Q-3) was obtained in the same manner as in Example 1 except for changing to 400 parts of methyl acid (Tokyo Chemical Industry Co., Ltd.).
The molar ratio of the phosphonium salt (S), the organic phenol compound (B), and the organic phenol compound (C) in (Q-3) was 1.00 / 1.38 / 1.00.

<Example 4>
Instead of 704 parts of the quaternary phosphonium base (A-Be1) in Example 1, 1200 parts of the quaternary phosphonium base (A-Be3) prepared in Preparation Example 3, 2,4 instead of butyl 4-hydroxybenzoate -400 parts of methyl dihydroxybenzoate (manufactured by Tokyo Chemical Industry Co., Ltd.), α, α, α'-tris (4-hydroxyphenyl) instead of 305 parts of 1,1,1-tris (4-hydroxyphenyl) ethane ) Epoxy resin curing accelerator (Q-4) was obtained in the same manner as in Example 1, except that the amount was changed to 305 parts of 1-ethyl-4-isopropylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.).
The molar ratio of the phosphonium salt (S), the organic phenol compound (B), and the organic phenol compound (C) in (Q-4) was 1.00 / 1.38 / 0.71.

<Example 5>
In the same manner as in Example 1, except that 400 parts of methyl 3,4-dihydroxy-2-methylbenzoate (Tokyo Chemical Industry Co., Ltd.) was used instead of butyl 4-hydroxybenzoate in Example 1, An epoxy resin curing accelerator (Q-5) was obtained.
The molar ratio of the phosphonium salt (S), the organic phenol compound (B), and the organic phenol compound (C) in (Q-5) was 1.00 / 1.20 / 1.00.

<Example 6>
An epoxy resin curing accelerator (Q-6) was used in the same manner as in Example 1 except that 400 parts of ethyl gallate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of butyl 4-hydroxybenzoate in Example 1. )
The molar ratio of the phosphonium salt (S), the organic phenol compound (B), and the organic phenol compound (C) in (Q-6) was 1.00 / 1.02 / 1.00.

<Comparative Example 1>
In the same manner as in Example 1, except that the quaternary phosphonium base (A-Be′1) produced in Comparative Production Example 1 was used instead of the quaternary phosphonium base (A-Be1) in Example 1, An epoxy resin curing accelerator (Q′-1) was obtained.

<Comparative example 2>
Epoxy resin curing accelerator in the same manner as in Example 1, except that 400 parts of 4,4′-dihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of butyl 4-hydroxybenzoate in Example 1. (Q′-2) was obtained.

<Comparative Example 3>
An epoxy resin curing accelerator (Q′-3) was used in the same manner as in Example 1 except that methyl salicylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of butyl 4-hydroxybenzoate in Example 1. Obtained.

<Comparative example 4>
An epoxy resin curing accelerator (Q′-4) was obtained in the same manner as in Example 1, except that catechol (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of butyl 4-hydroxybenzoate in Example 1. It was.

<Comparative Example 5>
Into a glass round bottom three-necked flask equipped with a dropping funnel and a reflux tube, 704 parts of the quaternary phosphonium base (A-Be1) produced in Production Example 1 was placed, and the phenol novolac resin 700 was adjusted while controlling the temperature at 50 ° C. Divided parts. The temperature was raised to 175 ° C. while distilling off the solvent (methanol), and then the remaining solvent was removed under reduced pressure to obtain an epoxy resin curing accelerator (Q′-5).

<Performance evaluation>
Epoxy resin curing accelerators (Q-1) to (Q-6) of the present invention prepared in Examples 1 to 6 and comparative epoxy resin curing accelerators (Q'-) prepared in Comparative Examples 1 to 5 The fluidity and curability of 1) to (Q′-5) were evaluated by the following methods.

<Flowability (flow value)>
100 parts of biphenyl type epoxy resin (softening point 105 ° C., epoxy equivalent 192), 78 parts by weight of p-xylylene phenol resin (softening point 80 ° C., hydroxyl equivalent 174), fused silica treated with 1% by weight of silane coupling agent To 1000 parts of powder, 1.5 parts of carnauba wax, 4 parts of antimony trioxide and 1 part of carbon black, 12 parts of the epoxy resin curing accelerator (Q) obtained in each example was uniformly ground and mixed, and then heated at 110 ° C. The mixture was melt-kneaded for 5 minutes using a roll, cooled and pulverized to obtain a sealing material. With respect to this sealing material, the flow value (unit: cm) of the spiral flow at 175 ° C. (70 kg / cm 2) was measured according to the method of EMMI 1-66 and used as an index of fluidity.

<Curing property (curing torque)>
Curing meter V-type (manufactured by Nichigo Shoji Co., Ltd., trade name) is used to set the curing torque for each of the above sealants under the conditions of a temperature of 175 ° C., a resin die P-200 and an amplitude angle of ± 1 °. The point at which the curing torque rises is the gel time (unit: seconds), and the value of the curing torque (unit: kgf · cm) 90 seconds after the start of measurement is used as an index of curability (strength and hardness at demolding). did.

Table 1 shows the evaluation results of the epoxy resin curing accelerator (Q) obtained in Examples 1 to 6 and Comparative Examples 1 to 5.

As is apparent from Table 1, the epoxy resin curing accelerators (Q) of Examples 1 to 6 of the present invention have a high flow value of the sealant after melt-kneading and excellent fluidity, and also have a curing torque. It can be seen that it is high and excellent in curability.
On the other hand, in Comparative Example 1 comprising a tetraalkylphosphonium cation, it can be seen that the flow value of the sealant after the melt mixing is very low because the stability of the phosphonium cation is low, and the moldability is poor.
In Comparative Examples 2, 4, and 5 that do not contain an ester group having a flexible structure, since the structure is rigid, it can be seen that the flow of the blend is poor and the flow value is low.
It can be seen that in Comparative Example 3 containing an ester group at the 2-position, the flow value is low. It can be seen that since there is a hydroxyl group next to the ester group, the flexibility of the ester is affected, the flow value is lowered, and the curability is also lowered.

The epoxy resin curing accelerator (Q) of the present invention is useful for producing an epoxy resin-based encapsulant for electronic parts such as semiconductors because it has excellent fluidity and curability after melt-kneading.

Claims

A phosphonium salt (S) comprising a quaternary phosphonium (A) represented by the general formula (1) and an anion of the organic phenol compound (B) represented by the general formula (2), an organic represented by the general formula (2) An epoxy resin curing accelerator (Q) comprising a phenol compound (B) and an organic phenol compound (C) represented by the general formula (3).

[In the formula (1), R 1 to R 3 represent an aryl group having 6 to 12 carbon atoms, and R 4 represents an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

[In Formula (2), R 5 to R 8 are the same or different and each represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or a hydroxyl group, and R 9 represents an alkyl group having 1 to 18 carbon atoms, An aryl group having 6 to 18 carbon atoms, a hydroxyalkyl group having 1 to 18 carbon atoms, a benzyl group, or an allyl group is represented. ]

[In the formula (3), R 10 represents hydrogen, an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms, and R 11 represents a functional group having 6 to 50 carbon atoms containing a phenol group. ]
2. The epoxy resin curing accelerator (Q) according to claim 1, wherein in general formula (2), R 5 is a hydroxyl group, and R 6 , R 7 , and R 8 are the same or different and each is hydrogen or a hydroxyl group.
The epoxy resin curing accelerator (Q) according to claim 1, wherein, in the general formula (2), R 5 is a hydroxyl group, R 6 and R 7 are hydrogen, and R 8 is a hydroxyl group.
2. The epoxy resin curing accelerator (Q) according to claim 1, wherein in general formula (2), R 6 is a hydroxyl group, and R 5 , R 7 , and R 8 are the same or different and each is hydrogen or a hydroxyl group.
The epoxy resin curing accelerator (Q) according to claim 1, wherein, in the general formula (2), R 6 is a hydroxyl group, and R 5 , R 7 , and R 8 are hydrogen.
The epoxy resin curing accelerator (Q) according to any one of claims 1 to 5, wherein in the general formula (2), R 9 is a methyl group, an ethyl group, a propyl group or a butyl group.
The epoxy resin curing accelerator (Q) according to any one of claims 1 to 6, wherein in the general formula (3), R 11 is a functional group represented by the general formula (4).
The epoxy resin curing accelerator (Q) according to any one of claims 1 to 6, wherein in the general formula (3), R 11 is a functional group represented by the general formula (5).

[In Formula (5), R 12 and R 13 each represent hydrogen, an alkyl group having 1 to 38 carbon atoms, or an aryl group having 1 to 38 carbon atoms. ]
The epoxy resin curing accelerator (Q) according to any one of claims 1 to 8, wherein the molar ratio of the phosphonium salt (S) and the organic phenol compound (B) is 99/1 to 1/99.
The epoxy resin curing accelerator (Q) according to any one of claims 1 to 9, wherein the molar ratio of the phosphonium salt (S) to the organic phenol compound (C) is 99/1 to 1/99.
The epoxy resin curing accelerator (Q) according to any one of claims 1 to 10, wherein the phosphonium salt (S) is synthesized by a salt exchange reaction between an alkyl carbonate of the quaternary phosphonium (A) and the organic phenol compound (B). .