JPH08165281A - Trimellitic anhydride-modified imidazole compound, its production and hardening accelerator - Google Patents

Abstract

PURPOSE: To obtain the subject compound useful as a hardening accelerator for producing an epoxy resin composition capable of giving a hardened article excellent in storage stability, fluidity, function of quick hardening, moisture resistance, adhesivity, etc. CONSTITUTION: This is a trimellitic anhydride-modified imidazole compound of formula I. The compound of formula I is obtained e.g. by reacting (A) a trimellitic anhydride of formula II with (B) 2-phenyl-4-methyl,-5- hydroxymethylimidazole of formula III in (C) methyl cellosolve. Further, the component B is slightly soluble in the component C at room temperature, and accordingly it is preferably dissolved under heating at 70-130 deg.C. The component A is used in an amount of 100-200 pts.wt., preferably 193 pts.wt. based on 188 pts.wt. of the component B, and the component C is used in an amount of 300-400 pts.wt., preferably 300 pts.wt. based on 188 pts.wt. of the component B.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an epoxy which is used as a curing accelerator and gives a cured product having good storage stability and fluidity and excellent properties such as fast curing property, moisture resistance and adhesiveness. The present invention relates to a trimellitic anhydride-modified imidazole compound capable of obtaining a resin composition, a method for producing the same, and a curing accelerator for an epoxy resin composition.

[0002]

2. Description of the Related Art
In the semiconductor industry, resin-sealed diodes, transistors, ICs, LSIs, and VLSIs have become the mainstream. Among them, epoxy resins, curing agents, and epoxy resin compositions containing various additives are generally It is superior in moldability, adhesiveness, electrical characteristics, mechanical characteristics, and moisture resistance to the thermosetting resin of.

Therefore, a semiconductor device is often sealed with an epoxy resin composition. However, in recent years, the degree of integration of these semiconductor devices has been increasing, and the chip size has been increasing accordingly.
On the other hand, the external dimensions of the package are becoming smaller and thinner with the demand for smaller and lighter electronic devices. Furthermore, as for the method of mounting semiconductor components on a circuit board, the surface mounting of semiconductor components has come to be often performed in order to increase the density of the components on the board.

When the semiconductor device is surface-mounted, a method of immersing the entire semiconductor device in a solder bath or passing through a high temperature zone where the solder melts is generally used. A crack may occur or peeling may occur at the interface between the lead frame or chip and the sealing resin. Such cracks and peeling become more remarkable if the sealing resin layer of the semiconductor device absorbs moisture before the thermal shock during surface mounting. However, in the actual work process,
Moisture absorption of the encapsulation resin layer is unavoidable, and therefore the reliability of the semiconductor device encapsulated with the epoxy resin composition after mounting may be greatly impaired. Therefore, as a countermeasure against such popcorn, the moisture absorption has been reduced by filling the epoxy resin composition with a high amount of filler. Further, in order to improve the moldability of a thin package, the viscosity of the epoxy resin composition has been lowered, and in order to further improve the productivity, a fast-curing catalyst has been studied for improving the molding cycle.

However, when a conventional curing catalyst such as a tertiary amine compound, a tertiary phosphine compound or a derivative thereof is used, there is a problem that the viscosity becomes high during kneading.

On the other hand, as an imidazole derivative, JP-A-58-76420 and JP-A-58-103525.
Japanese Patent Publication No. 57-100128, Japanese Patent Publication No. 6-
In 18853, a curing agent for an epoxy resin obtained by a reaction of 2-methylimidazole with pyromellitic dianhydride and trimellitic dianhydride is used to give a curing agent having good storage stability and excellent moisture resistance. Epoxy resin compositions have been proposed.

However, these curing catalysts must be used in a large amount because of their lack of rapid curing property, which deteriorates the storage stability of the epoxy resin composition. Further, an epoxy resin composition which gives a cured product having excellent storage stability, fluidity, and excellent characteristics such as fast curing property and moisture resistance, simply by blending these curing agents and curing accelerators together. It was difficult to get things.

[0008] The present invention has been made in view of the above circumstances,
Trimellitic anhydride modification which can be used as a curing accelerator to obtain an epoxy resin composition that has excellent storage stability, fluidity, and excellent properties such as fast curing and moisture resistance An object of the present invention is to provide an imidazole compound, an industrially advantageous method for producing the compound, and an effective curing accelerator for an epoxy resin composition.

[0009]

Means and Action for Solving the Problems The present inventors have
As a result of repeated intensive studies in order to solve the above problems, as shown in the following reaction formula, by reacting trimellitic anhydride and 2-phenyl-4-methyl-5-hydroxymethylimidazole in methylcellosolve, An epoxy resin composition containing a trimellitic anhydride-modified imidazole compound represented by the following structural formula (1) and containing the compound of the formula (1) in an epoxy resin, a curing agent, and optionally an inorganic filler When blended as a curing accelerator of, it is possible to obtain an epoxy resin composition that gives a cured product having excellent storage stability and fluidity, fast curing properties, and moisture resistance, as well as excellent adhesiveness. The inventors have found what can be done and have completed the present invention.

[0010]

Embedded image

Therefore, according to the present invention, the trimellitic anhydride-modified imidazole compound of the above formula (1), trimellitic anhydride and 2-phenyl-4-methyl-5-hydroxymethylimidazole are reacted in methyl cellosolve. Provided is a method for producing a trimellitic anhydride-modified imidazole compound of the formula (1), and a curing accelerator for an epoxy resin composition comprising the trimellitic anhydride-modified imidazole compound of the formula (1).

The present invention will be described in more detail below. The trimellitic anhydride-modified imidazole compound of the present invention is represented by the following structural formula (1).

[0013]

Embedded image

The compound of the formula (1) can be obtained by reacting trimellitic anhydride with 2-phenyl-4-methyl-5-hydroxymethylimidazole in a methylcellosolve solvent, particularly 2-phenyl. -4-
Methyl-5-hydroxymethylimidazole is heated and dissolved in methylcellosolve, and then excess trimellitic anhydride is added to cause a reaction, and the obtained reaction product is poured into a large amount of acetone to precipitate the reaction product. ,Obtainable.

More specifically, 2-phenyl-4-methyl-5-hydroxymethylimidazole is sparingly soluble in methyl cellosolve at room temperature, and heating is required for dissolution. The heating temperature is preferably 70 to 130 ° C, more preferably 100 to 120 ° C. In this case, the amount of methyl cellosolve is 300 to 400 parts by weight, preferably 300 parts by weight, based on 188 parts by weight (1 mol) of 2-phenyl-4-methyl-5-hydroxymethylimidazole. If less than 300 parts by weight, 2-phenyl-4
-Methyl-5-hydroxymethylimidazole is not sufficiently dissolved, and the reaction may not proceed uniformly. Also, 4
If it is more than 00 parts by weight, the yield of the reaction product when precipitated in acetone may decrease. As the solvent, methylcellosolve may be used alone, and if necessary, a solvent such as dimethylsulfoxide, dimethylformamide, diethylene glycol, pyridine, etc. may be used together within the range not impairing the object of the present invention.

On the other hand, the amount of trimellitic anhydride is 100 to 200 parts by weight (1.0 to 1.2 times) with respect to 188 parts by weight (1 mol) of 2-phenyl-4-methyl-5-hydroxymethylimidazole. Mol), preferably 193
It is about part by weight (1.1 times mol). The reason why trimellitic anhydride is added in a larger amount than that of 2-phenyl-4-methyl-5-hydroxymethylimidazole is that trimellitic anhydride has good solubility in methyl cellosolve and acetone at room temperature.

This trimellitic anhydride can be removed by precipitating the compound obtained by the reaction in acetone and then washing the precipitate with acetone several times. The amount of acetone necessary for precipitating this compound is 600 ml to 300 per 188 parts by weight (1 mol) of 2-phenyl-4-methyl-5-hydroxymethylimidazole.
0 ml is preferable, more preferably 1000 ml to 15
It is 00 ml. If the amount of acetone is less than 600 ml, the yield of the reaction product may deteriorate.
If it is more than 1, the process cost may increase and the cost may increase. In addition, it is necessary to pay attention to water absorption in the washing process. Upon absorption of water, the acid anhydride reactant opens the ring and becomes a dicarboxylic acid derivative. When the ring-opened dicarboxylic acid derivative is used as a curing catalyst for an epoxy resin composition, it is difficult to use because it has no compatibility.

In order to confirm the compound of the formula (1), it is effective to measure the melting point by instrumental analysis. The melting point of this compound is 253 ° C to 258 ° C.

The trimellitic acid-modified imidazole compound of the above formula (1) of the present invention is effectively used as a curing accelerator for an epoxy resin composition.

The epoxy resin composition containing the compound of formula (1) will be described in detail. The epoxy resin composition contains an epoxy resin, a curing agent and, if necessary, an inorganic filler. In this case, the epoxy resin may be any one as long as it has at least two epoxy groups in one molecule. Examples thereof include bisphenol A type epoxy resin, novolac type epoxy resin, alicyclic epoxy resin, glycidyl type epoxy resin, biphenyl type epoxy resin, naphthalene ring-containing epoxy resin, cyclopentadiene containing epoxy resin, and polyfunctional epoxy resin. . Further, these epoxy resins may be appropriately combined. Above all, a biphenyl type epoxy resin or a naphthalene ring-containing epoxy resin is desirable for highly filling the inorganic filler. These epoxy resins preferably have a softening point of 50 to 100 ° C. and an epoxy equivalent of 100 to 400. Further, a brominated epoxy resin can be used for flame retardancy.

On the other hand, as the curing agent, a known curing agent for epoxy resin is used, for example, phenol resin can be used. As the phenol resin, phenol novolac resin, triphenol methane resin, phenol aralkyl resin, naphthalene ring-containing phenol resin,
Examples thereof include those having two or more phenolic hydroxyl groups such as a cyclopentadiene-containing phenol resin and a terpene ring-containing phenol resin. Among the phenolic resins, those having a softening point of 60 to 120 ° C. are preferable. The hydroxyl equivalent is preferably 90 to 150. The amount of the curing agent used is a curing effective amount. For example, when a phenol resin is used, the amount of the phenol resin used may be any amount as long as the equivalent ratio of epoxy group and hydroxyl group is in the range of 0.5 to 2.0. Although good, it is usually 30 to 100 parts by weight, preferably 40 to 70 parts by weight, based on 100 parts by weight of the epoxy resin. With 30 parts by weight, sufficient strength cannot be obtained, while 100 parts by weight and unreacted phenol resin remain to lower the moisture resistance.

The inorganic filler is indispensable especially when the epoxy resin composition is used for encapsulating a semiconductor, and is for reducing the expansion coefficient of the encapsulating material and the stress applied to the semiconductor element. Is. As specific examples, fused silica having a crushed or spherical shape and crystalline silica are mainly used. In addition to this, alumina, silicon nitride, aluminum nitride, etc. can be used.

The average particle size of the inorganic filler is 5 to 40.
The micron type is preferable. Particularly preferably 10 to 30
It is of the micron type. It is desirable that this type of inorganic filler be used after being surface-treated with a silane coupling agent in advance. The content of the inorganic filler is preferably 200 to 900 parts with respect to 100 parts of the total amount of the resin components.
If it is less than 0 part, the expansion coefficient becomes large and the stress applied to the semiconductor element increases, which may lead to deterioration of element characteristics. If it exceeds 900 parts, the viscosity at the time of molding becomes high and the moldability deteriorates. There is.

Further, when used as an encapsulant for semiconductors, it is preferable to add a silicone-based flexibility-imparting agent to the epoxy resin composition in order to reduce stress. Examples of the flexibility imparting agent include silicone rubber powder, silicone gel, block polymers of organic resin and silicone polymer, and the like. Instead of adding such a flexibility-imparting agent, the surface of the inorganic filler may be treated with a two-component type silicone rubber or silicone gel. The amount of the flexibility-imparting agent used is preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight, based on the entire composition. If the amount is less than 0.5% by weight, sufficient impact resistance is obtained. May not be given, and if it exceeds 10% by weight, mechanical strength may become insufficient.

If desired, other optional components may be added to the epoxy resin composition within a range that does not impair the effects of the present invention. Such optional components include, for example, carnauba wax, higher fatty acids, difficult-to-use agents such as synthetic waxes, silane coupling agents, antimony oxide, phosphorus compounds and the like.

The above-mentioned compound of the formula (1) of the present invention is added to such an epoxy resin composition as a curing accelerator (curing catalyst).
In this case, when the compound of the formula (1) is blended with the epoxy resin compound, the method of using the compound of the formula (1) in the form of fine powder or the method of dispersing the compound in the phenol resin for use is is there. As the blending amount,
The total amount of the resin components is 0.1 to 10 parts by weight, preferably 0.3 to 5.0 parts by weight, based on 100 parts by weight. 0.1
If the amount is less than 10 parts by weight, it cannot be cured in a short time, and 10
If the amount is more than parts by weight, the curing rate may be too fast to obtain a good molded product, and the storage stability may be deteriorated.

The epoxy resin composition contains, in addition to the curing catalyst of the present invention, imidazole or a derivative thereof, a phosphine derivative such as triphenylphosphine, tris P-methoxyphenylphosphine and tricyclohexylphosphine, diazabicycloundecene. It is also possible to mix it with a catalyst such as a cycloamidine derivative such as (DBU).

In the production of the above-mentioned epoxy resin composition, predetermined amounts of the above-mentioned components are uniformly stirred and mixed, and kneaded with a kneader, roll, extruder or the like preheated to 70 to 95 ° C. and cooled. It can be obtained by a method such as crushing. The order of mixing the components is not particularly limited.
Such an epoxy resin composition can be suitably used for encapsulating a semiconductor device such as an IC, an LSI, a transistor, a thyristor and a diode, and can also be effectively used for manufacturing a printed circuit board. Here, when the semiconductor device is sealed, the molding temperature of the resin composition for semiconductor sealing is 150.
~ 180 ° C, post cure at 150 ~ 180 ° C, 2-1
It is preferable to carry out for 6 hours.

[0029]

INDUSTRIAL APPLICABILITY In the trimellitic anhydride-modified imidazole compound and the process for producing the same of the present invention, the reaction between trimellitic anhydride and 2-phenyl-4-methyl-5-hydroxymethylimidazole is carried out in methyl cellosolve. Can be produced industrially advantageously, and this trimellitic anhydride and 2-phenyl-4-methyl-5 can be produced.
When an epoxy resin was prepared using a reaction product (compound of the formula (1)) with -hydroxymethylimidazole as a curing catalyst, the storage stability and fluidity were good, and the rapid curing property and the moisture resistance were excellent. An epoxy resin composition that gives a cured product can be obtained.

[0030]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. All parts in each example are parts by weight.

[Example 1] 188 parts of 2-phenyl-4-methyl-5-hydroxymethylimidazole in a four-necked flask equipped with a 1 L thermometer, a stirrer and a reflux condenser [Shikoku Kasei Co., Ltd., trade name 2P4MHZ ] And 300 parts of methyl cellosolve were added. 12 while stirring
The mixture was heated to 0 ° C to dissolve 2-phenyl-4-methyl-5-hydroxymethylimidazole. After heating and dissolving, a solution prepared by dissolving 193 parts of trimellitic anhydride (manufactured by Tokyo Kasei Co., Ltd.) in 100 parts of methyl cellosolve was dropped from a dropping funnel and reacted with 2-phenyl-4-methyl-5-hydroxymethylimidazole. Let After dropping, 120
The reaction was carried out at 0 ° C for 1 hour and then cooled to 50 ° C. Then 3
1000 ml of acetone was placed in a L beaker, the above reaction mixture was charged while stirring, and the precipitate was collected by filtration. The filtration residue was put into 500 ml of acetone, stirred for 30 minutes, and washed three times by filtration. Then, the filtration residue was removed at 100 ° C. under reduced pressure to remove the solvent methylcellosolve to obtain Compound A (compound represented by the above formula (1)) as a pale red solid. The melting point of the obtained compound A was 255 ° C.

The results of elemental analysis of this compound A are shown below.

C H N Compound A Calculated value (%) 63.16 4.21 7.37 Measured value (%) 63.34 4.53 7.51 The infrared absorption spectrum of this compound A is shown in FIG. Show.

[Examples 2 to 5] By the same method as in Example 1, 2-phenyl-4-methyl-5-hydroxymethylimidazole, trimellitic anhydride, methyl cellosolve used in the reaction, methyl used in the dropping. Cellosolve and acetone necessary for precipitation were used in parts by weight in Table 1 to obtain compounds B, C, D, and E as pale red solids.

Comparative Examples 1 and 2 In the same manner as in Example 1, dimethylsulfoxide and dimethylformamide were used as a solvent in an amount of parts by weight shown in Table 1 to obtain compounds F and G as pale yellow solids.

[0036]

[Table 1]

From the results of Table 1, trimellitic anhydride and 2
It was confirmed that in the system using methyl cellosolve as the reaction solvent for -phenyl-4-methyl-5-hydroxymethylimidazole, the compound of formula (1) can be synthesized in good yield.

[Examples 6 to 9 and Comparative Examples 3 to 5] As shown in Table 2, an epoxy resin, a phenol resin, the compound A obtained in Example 1 was used, and wax E 1.5 was used.
Parts, carbon black 1 part, brominated epoxy resin 6
Parts, 7 parts of antimony trioxide, 500 parts of fused silica powder and 2 parts of γ-glycidoxypropyltrimethoxysilane were uniformly melt-mixed with a hot double roll, cooled and pulverized to prepare an epoxy resin composition. . As a comparative example, unreacted 2
An epoxy resin composition was prepared in the same manner using -phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ), and their physical properties were compared.

The following tests (a) to (e) were conducted on these epoxy resin compositions. The results are shown in Table 2.

(A) Spiral flow 175 ° C., 70 k using a mold conforming to the EMMI standard
It was measured under the condition of g / cm ² .

(B) Hot hardness The hot hardness when a 10 × 4 × 100 mm bending bar was molded under the conditions of 175 ° C., 70 kg / cm ² , and molding time of 90 seconds was measured with a Barcol hardness meter.

(C) Storage stability The number of days when the spiral flow value reached 80% of each initial value when each material was left at 25 ° C. was shown.

(D) Gelation time The gelation time of the composition was measured at 175 ° C.

(E) Melt Viscosity 175 using a high-performance flow tester (manufactured by Shimadzu Corporation)
It was measured at ° C.

[0045]

[Table 2]

From the results of Table 2, trimellitic anhydride and 2
-Phenyl-4-methyl-5-hydroxyimidazole salt (compound of formula (1)) as a curing accelerator (curing catalyst)
The epoxy resin composition used as is, compared with the epoxy resin composition using unreacted 2-phenyl-4-methyl-5-hydroxymethylimidazole, viscosity increase at the time of kneading is less, flowability, storage It was confirmed to provide a composition having good stability and excellent curability.

[Brief description of drawings]

FIG. 1 is an infrared absorption spectrum of a trimellitic anhydride-modified imidazole compound of the present invention.

Claims (3)

[Claims] 1. A trimellitic anhydride-modified imidazole compound represented by the following structural formula (1). Embedded image 2. Trimellitic anhydride and 2-phenyl-4
-Methyl-5-hydroxymethylimidazole is reacted in methylcellosolve.
A method for producing the trimellitic anhydride-modified imidazole compound described. 3. A curing accelerator for an epoxy resin composition, which comprises the trimellitic anhydride-modified imidazole compound according to claim 1.