JPH06172616A - Epoxy resin composition and its production - Google Patents

Abstract

PURPOSE:To reutilize a heat-treated pulverized substance of an epoxy resin cured product as a filler. CONSTITUTION:An epoxy resin cured product is pulverized and reutilized as a filler for an epoxy resin composition. In the process, this pulverized substance of the cured product is heat-treated. The fluidity of the epoxy resin composition containing the pulverized substance added thereto in molding thereof can be improved by this treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition suitable for encapsulation of electronic parts and structural materials, and a method for producing the same.

[0002]

2. Description of the Related Art Epoxy resin compositions are widely used for sealing electronic parts such as capacitors, transformers, transistors, ICs, LSIs, and various structural materials such as building materials and earth and wood. The reason for this is that the electrical properties, heat resistance, mechanical properties, and adhesiveness are excellent.

[0003]

Epoxy resin is consumed in a large amount due to such excellent characteristics, but with this, molding residue such as cull part and runner part generated in the sealing process of electronic parts and The amount of waste of cured epoxy resin such as various molded products has risen to a huge amount. Since epoxy resin is a thermosetting resin, what is heated and hardened in these molding processes cannot be remelted, so it is not recycled like thermoplastic resin, but most of it is landfilled at the disposal site. It is a big problem from the viewpoint of effective use and environmental conservation.

Therefore, it is desired to develop a method for effectively reusing an epoxy resin cured product such as such a molding residue or product waste to reduce the amount of waste and utilize it as a valuable resource. It is rare. On the other hand, it has been studied to pulverize such a waste product of a cured product and add it as a filler for an epoxy resin composition for use.

When used as a filler, it is important to increase the addition amount of the crushed product of the cured product in order to increase the recycling rate and reduce the cost. However, until now, the higher the amount added, the higher the viscosity of the epoxy resin composition to which it was added, the fluidity at the time of molding was lowered, and the filling property of the molded body was insufficient, and as a result,
There is a problem that various physical properties, particularly mechanical strength and thermal shock resistance, are deteriorated.

[0006]

The epoxy resin composition of the first invention is an epoxy resin composition containing an epoxy resin, a curing agent, and a pulverized product of a cured epoxy resin,
It is characterized in that the crushed product of the cured epoxy resin is heat-treated.

The method for producing an epoxy resin composition of the second invention is the method for producing an epoxy resin composition in which an epoxy resin, a curing agent and a pulverized product of an epoxy resin cured product are mixed or kneaded. The pulverized product is characterized in that the cured epoxy resin is pulverized after being heated or pulverized and then heated.

[0008]

The crushed product of the cured epoxy resin of the present invention is a crushed product obtained by curing a composition comprising an epoxy resin and a curing agent by a curing reaction. For example, it is obtained by crushing a molding residue such as a cull portion or a runner portion, which is a by-product in the step of sealing an electronic component with an epoxy resin composition, or a cured resin portion of a molded product, by a crusher.

The heat treatment conditions for these pulverized cured products are 70
C. to 200.degree. C. are preferred. If the temperature is 70 ° C or lower, the heat treatment is insufficient and the effect of improving the fluidity during molding is small.
If the temperature exceeds 0 ° C, the deterioration of the resin becomes severe and the physical properties are adversely affected. The longer the heat treatment time is, the more effective it is to improve the fluidity. However, when the heat treatment temperature is high, the resin may be deteriorated and the physical properties may be adversely affected if the heat treatment is carried out for a long time. Therefore, when the temperature is 120 ° C or higher, it is preferably within 24 hours.

The average particle size of these crushed products is 5 μm.
To 100 μm is preferable. If it is 5 μm or less, the viscosity increases when it is filled in the epoxy resin composition, which hinders the moldability, and if it exceeds 100 μm, the electronic parts may be damaged when the electronic parts are sealed with the crushed product of the cured product. Becomes higher.

The epoxy resin and the curing agent used in the crushed product of the cured product are those generally used as a sealing material or a structural material for electronic parts. Specifically, first, an epoxy resin is a compound having two or more epoxy groups in one molecule, and examples thereof include diglycidyl ethers such as bisphenol A and bisphenol F, polyglycidyl ethers of phenol novolac resin and cresol novolac resin, Examples thereof include alicyclic epoxy resins produced by epoxidation of olefin bonds, and mixtures thereof. A curing agent is a compound that reacts with an epoxy resin to cause a curing reaction, such as phenol resin such as finol novolac or cresol novolac, phthalic anhydride, hexahydrophthalic anhydride, methylhymic anhydride, pyromellitic anhydride, etc. Acid anhydrides, amines such as diethylenetriamine and N-aminoethylpiperazine, and polyamide resins. Inorganic fillers and other additives may be added as required.

The inorganic filler refers to an inorganic powder or fibrous material, such as crystalline silica, fused silica, alumina, silicon nitride, calcium carbonate, and the like, or cut glass fibers, and two or more of these. A mixture of

A curing accelerator is added to accelerate the curing reaction, and it is used especially when a phenol resin or an acid anhydride is used as the curing agent. For example, imidazoles such as 1,2-dimethylimidazole, 2-phenylimidazole, 2-heptadecylimidazole, triethanolamine, benzyldimethylamine, triethylenediamine,
Tertiary amines such as 1,8-diazabicyclo- (5,4,0) -7-undecene (hereinafter abbreviated as DBU), organic phosphorus compounds such as triphenylphosphine and methyldiphenylphosphine, triphenylphosphine tetra Examples thereof include organoboron compounds such as phenylborate, 2-ethyl-4methylimidazole tetraphenylborate, tetraphenylphosphonium tetraphenylborate, and the like, and mixtures thereof.

In order to improve the releasability when molded, an internal release agent is added, for example, montanic acid, stearic acid or their metal salts or esters, carnapa wax and the like. A coupling agent is added in order to improve the adhesion and compatibility of the filler and the resin, and examples thereof include silane coupling agents such as glycidoxypropyltrimethoxysilane and aminopropyltriethoxysilane, and titanate coupling agents. To be A flame retardant is added to enhance flame retardancy, for example, a combination of brominated epoxy resin and antimony trioxide only. A coloring agent is added in order to color the composition to a predetermined color, and examples thereof include carbon plaque. A stress reducing agent is added to reduce the stress of the composition, and examples thereof include a modified silicone compound, a silicone rubber, and a butadiene rubber.

The above components are usually mixed with a mixer or the like, and then, if necessary, kneaded with a heated roll or kneader to obtain a composition. Then, it is hardened by a processing reaction when it is formed by a transfer molding method or a casting method.
At this time, the curing rate is adjusted by heating if necessary.

Next, other components of the epoxy resin composition of the present invention will be described. Other components include epoxy resins and hardeners. If necessary, change agents such as a curing accelerator, an internal mold release agent, a coupling agent, a flame retardant, a coloring agent, and a stress reducing agent are added. These generally refer to those used for sealing materials of electronic parts and structural materials, and include, for example, those listed as examples of pulverized products of the above-mentioned cured epoxy resin.

In addition to this, a usual inorganic filler can be added together with the pulverized product of the cured epoxy resin. At that time, the total ratio of the pulverized product of the cured product or the pulverized product of the cured pair and the inorganic filler to the entire composition is preferably 50 to 90% by weight, and more preferably 60 to 85% by weight. If it is less than 50% by weight, the strength and thermal shock resistance of the sealed product will be insufficient, and if it exceeds 90% by weight, the formability will be impaired.
As a result, various physical properties deteriorate.

Next, a method for producing the epoxy resin composition for encapsulating electronic parts of the present invention will be described.

The heat treatment of the crushed product of the epoxy resin cured product
It is performed by a heating device before or after crushing the cured body. The hardened material is crushed with a crusher. At that time, after pulverizing with a coarse pulverizer such as a roll mill, a rotary cutter mill, or a jockey, fine pulverization with a vibration mill, a ball mill or the like enables efficient pulverization to a predetermined particle size. The particle size can also be adjusted with a classifier such as a vibrating screen. The pulverized product, the epoxy resin and the curing agent are mixed and / or kneaded with a mixer to produce a composition. Additives are added to the mixer with these as needed. For example, when using an epoxy resin or curing agent with a softening point above room temperature,
The components are mixed with a mixer and kneaded with a roll or a kneader heated above the softening point of the resin to produce a composition. Then, after cooling with a press, roll, etc., it is crushed into tablets if necessary. When the resin has a softening point of not higher than room temperature, the components are mixed with a mixer to produce a composition. At this time, the mixer is heated as necessary, and the composition is degassed in vacuum.

The composition thus produced has the respective components uniformly mixed, and is excellent when the electronic parts are sealed by the trans-pour molding method or the casting method or when it is used as a structural material. Shows moldability and various properties.

[0021]

EXAMPLES Examples will be described below. The scope of the present invention is not limited to these examples.

First, as Example 1, 400 parts of silica A (manufactured by Tatsumori Co., Ltd., Crystallite AA) (hereinafter, all by weight) and 80 parts of cresol novolac type epoxy resin (ESCN195XL manufactured by Sumitomo Chemical Co., Ltd.). , Brominated epoxy resin A (ESB-340 manufactured by Sumitomo Chemical Co., Ltd.) 2
0 parts, phenol novolac resin (Showa Polymer Co., Ltd.)
Of BRG556), 2 parts of 2-heptadecylimidazole, 8 parts of antimony trioxide, 2 parts of carbon black, 3 parts of γ-glycidoxypropyltrimethoxysilane and 2 parts of carnauba wax. The materials were mixed with a mixer, kneaded with a heating roll at 100 ° C. for 5 minutes, and then immediately cooled by a press to obtain a sheet-shaped uncured composition. After crushing this, tabletize, preheat,
Molding was carried out in a mold for a 54-pin flat package equipped with a 42 alloy lead frame at 180 ° C. for 3 minutes using a transfer molding machine. Then, the molding residue of the cull part and the runner part was taken out, and this was crushed to an average particle size of 15 μm using a roll mill and a vibration mill. Then, this was heated in a dryer at 180 ° C. for 10 hours. Hereinafter, this is referred to as pulverized product A.

The pulverized product A and other compounds were mixed in a ratio shown in Table 1 with a mixer, kneaded with a heating roll at 100 ° C. for 5 minutes, and then cooled with a press to obtain an epoxy resin composition for sealing electronic parts. I got a thing. The test of the measurement items in Table 2 was performed using this composition. The results obtained are shown in Table 3.

As Example 2, the pulverized product A and other compounds were mixed and kneaded in the proportions shown in Table 1 in the same manner as in Example 1 to obtain an epoxy resin composition for encapsulating electronic parts. Using this, tests of the evaluation items in Table 2 were conducted, and the results are shown in Table 3.

As Example 3, silica B (Electrochemical Co., Ltd.)
FS90) 420 parts, cresol novolac type epoxy resin (Sumitomo Chemical Co., Ltd. ESCN220F) 80 parts, brominated epoxy resin A (Sumitomo Chemical Co., Ltd., E
SB-340), 20 parts, phenol novolac resin (Showa High Polymer Co., Ltd., BRG557) 45 parts, DBU
2 parts, antimony trioxide 8 parts, γ-glycidoxypropyltrimethoxysilane 3 parts, carbon black 2 parts, carnauba wax 2 parts, modified silicone A (Shin-Etsu Chemical Co., Ltd., X-22 -161C) was mixed and kneaded in the same manner as in Example 1 in the same manner as in Example 1 and then molded, and the remaining cull part and runner part were dried by a drier.
After heat treatment at 0 ° C. for 8 hours, it was ground to an average particle size of 23 μm using a rotary cutter mill and a vibration mill. Hereinafter, this is referred to as pulverized product B. This was mixed and kneaded with other compounds in the proportions shown in Table 1 in the same manner as in Example 1 to obtain an epoxy resin composition for encapsulating electronic components. Using this, the tests of the evaluation items in Table 2 were conducted, and the results are shown in Table 3.

As Example 4, Sumitomo Bakelite Co., Ltd.
Epoxy resin composition EME600 for encapsulating electronic components
0 was molded in the same manner as in Example 1, and the molding residue was crushed to an average particle size of 10 μm. This is heat-treated at 120 ° C. for 23 hours, and hereinafter referred to as pulverized product C. This was mixed with other blends in the proportions shown in Table 1 in the same manner as in Example 1
The mixture was kneaded to obtain an epoxy resin composition for sealing electronic parts.
Using this, tests of the evaluation items in Table 2 were conducted, and the results are shown in Table 3.

As Example 5, ground material A, brominated epoxy resin B (manufactured by Sumitomo Chemical Co., Ltd., ELB240) and other blends were mixed in a mixer at a ratio shown in Table 1, further degassed and allowed to stand at room temperature. A liquid epoxy resin composition for encapsulating electronic components was obtained. Using this, tests of the evaluation items in Table 2 were conducted, and the results are shown in Table 4.

As Example 6, an epoxy resin composition EME5000 manufactured by Sumitomo Bakelite Co., Ltd. for encapsulating electronic parts
Was molded in the same manner as in Example 1, heat-treated at 190 ° C. for 3 hours, and then pulverized to an average particle size of 35 μm. Hereinafter, this is referred to as pulverized product D. This and other compounds were mixed in a mixer at a ratio shown in Table 1 and defoamed to obtain an epoxy resin composition for encapsulating electronic components which was liquid at room temperature. Using this, tests of the evaluation items in Table 2 were conducted, and the results are shown in Table 4.

For comparison, in the epoxy resin compositions of Examples 1 to 6, the cases in which the pulverized products of the hardened bodies added thereto were not heat-treated are set as Comparative Examples 1 to 6, respectively, and the evaluation items of Table 2 are shown. Was tested. The results are shown in Table 3.
And shown in Table 4.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

As is clear from Tables 3 and 4, when the crushed product of the cured epoxy resin is heat-treated, the viscosity of the epoxy resin composition added with this as a filler and the fluidity at the time of molding can be greatly improved. Moreover, it has been found that various physical properties such as mechanical strength, thermal shock resistance, and moisture resistance can be favorably maintained.

[0034]

As described above, according to the present invention, it is possible to reuse an epoxy resin cured product which has been discarded until now as a filler for an epoxy resin composition, and as a result, a large amount of this waste amount can be obtained. It is possible to reduce the cost and cost of the epoxy resin composition.

Claims (2)

[Claims] 1. An epoxy resin composition containing an epoxy resin, a curing agent, and a pulverized product of an epoxy resin cured product, wherein the pulverized product of the epoxy resin cured product is heat-treated. Resin composition. 2. A method for producing an epoxy resin composition, which comprises mixing or kneading an epoxy resin, a curing agent, and a crushed product of an epoxy resin cured product, wherein the crushed product of the epoxy resin cured product is crushed after heating the epoxy resin cured product. Or a method of producing an epoxy resin composition, characterized by being heated after crushing.