JPH07238145A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin compsn. of which the crack resistance is not degraded by the remaining stress occurring during curing and is excellent in mechanical properties such as bending and impact strengths. CONSTITUTION:This epoxy resin compsn. comprises an epoxy resin liq. at room temp., an acid anhydride curative liq. at room temp., and an alkanolamine represented by formula I (wherein n is an integer of 1-20) or formula II.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an epoxy resin composition for encapsulating electric / electronic parts.

[0002]

2. Description of the Related Art A cured epoxy resin is widely used as a sealing material for electric / electronic parts because it has excellent electric insulation, heat resistance, moisture resistance and adhesion. Acid anhydrides as epoxy resin curing agents for sealing electrical and electronic parts,
Amines and polyamides are mainly used.

Among these curing agents, acid anhydrides generally have a low viscosity, and since the amount of the acid anhydride compounded in the epoxy resin is larger than that of other curing agents, the viscosity of the epoxy resin composition is low and the work is difficult. It has excellent properties. In addition, it is less irritating to the skin and excellent in handleability as compared with other curing agents such as amines. Furthermore, the reaction with the epoxy resin is relatively slow, and it is usually used by adding an accelerator such as a tertiary amine. However, the pot life of the compound is longer than that of amines and the heat generated during curing is also increased. Curing strain is small because it is small, making it easy to make large castings. Further, the cured product has a higher glass transition temperature than the cured product using amines, and is excellent in electrical properties and mechanical properties. However, it is generally a drawback that curing requires a high temperature and a long time of 100 ° C. or more. This problem can be solved by increasing the amount of the accelerator added, but the heat generation during curing becomes extremely large, and the residual strain in the resin cured product causes the mechanical properties characteristic of the acid anhydride cured product to be significantly impaired. Be done.

Although amines and polyamides are inferior to acid anhydrides in the above-mentioned points, cured products having an amine network in the resin skeleton are generally excellent in toughness. Glycidylamine can be considered as another method of introducing an amine network into the resin skeleton, but it is difficult to handle because of the problem of the storage stability of the epoxy resin.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides an epoxy resin composition which generates little heat during curing and is excellent in toughness.

[0006]

The present invention is represented by the general formula (1) or the general formula (2) in an epoxy resin composition comprising an epoxy resin which is liquid at room temperature and an acid anhydride curing agent which is liquid at room temperature. An epoxy resin composition containing an alkanolamine.

[0007]

[Chemical 1] (In the formula, n: an integer of 1 to 20)

[0008]

[Chemical 2] (In the formula, n: an integer of 1 to 20)

In the present invention, the liquid epoxy resin is 1
The resin has an average of two or more epoxy groups per molecule, and examples of such a resin include glycidyl of polyhydric phenol such as 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, and resorcin. Glycidyl ether of water-added compound of polyhydric phenol such as ether, 2,2-bis (4-hydroxyhexyl) propane,
Glycidyl ethers such as phenol novolac and cresol novolac, vinyl cyclohexene oxide,
(3 ', 4'-epoxycyclohexylmethyl) -3,4-epoxycyclohexanecarboxylate, (3', 4'-epoxy-6'-methyl-cyclohexylmethyl) -3,4-epoxy-6-methylcyclohexanecarboxy Alicyclic epoxy resin such as phthalate, glycidyl ester such as diglycidyl phthalate, diglycidyl hexahydrophthalate, p-
Examples thereof include glycidyl ether esters such as oxybenzoic acid glycidyl ether ester, and glycidyl ethers of fatty acid alcohols such as ethylene glycol, trimethylolpropane, and pentaerythritol. Further, these resins can be used in combination.

The liquid acid anhydride curing agent is a mixture of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, etc., which has a low melting point, or an isomer mixture has a low melting point, etc. It is an organic carboxylic acid anhydride that has been liquefied at room temperature by the above method.

The alkanolamine forms a half ester with a carboxylic acid anhydride at room temperature, but a pre-reacted one may be used. The generated half ester also acts as a curing accelerator, but is incorporated into the skeleton of the cured product during curing. Therefore, as curing progresses, the activity as a curing accelerator gradually decreases, and the heat of curing is suppressed. Therefore, good crack resistance due to distortion due to heat generation during curing,
Less decrease in toughness. The obtained cured product has an amine network and is excellent in original toughness.

The content of alkanolamine is 0.5 based on the total amount of the epoxy resin and the acid anhydride curing agent.
-10 wt% is suitable. If the content is less than 0.5% by weight, the compounding effect cannot be obtained. On the other hand, if the content exceeds 10% by weight, the compatibility between the acid anhydride curing agent and the alkanolamine remarkably decreases, and the toughness of the cured product also decreases. Although the alkanolamine acts as a curing accelerator alone, nitrogen compounds such as tertiary amines and imidazoles, phosphorus compounds such as phosphines and phosphonium salts may be used in combination with the curing accelerator.

The epoxy resin composition of the present invention may further contain other components depending on the purpose for which it is used. That is,
A reactive diluent such as phenylglycidyl ether, a filler such as silica powder, a coloring agent such as carbon black, a defoaming agent, a release agent, a fluidity adjusting agent and the like can be added.

The epoxy resin composition of the present invention may be manufactured in the same manner as a general epoxy resin composition. That is, it can be produced by stirring and mixing an epoxy resin, an epoxy resin curing agent, an alkanolamine and, if necessary, other components using a disperser, a kneader, a mixing roll and the like.

[0015]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the examples and comparative examples, "part" means "part by weight".

(Example 1) Epicoat 828 (manufactured by Yuka Shell Epoxy Co., Ltd.) 100 parts Methylhexahydrophthalic anhydride 85 parts Ethylenediamine propylene oxide adduct 8 parts (Adeka Polyether EDP-450 manufactured by Asahi Denka Co., Ltd.) ) The above components were stirred and mixed to obtain a resin composition. The resin composition thus obtained was cured at 100 ° C. for 2 hours, the curing exothermic temperature was measured, and further cured at 150 ° C. for 2 hours to obtain a cured resin product.

(Example 2) Epicoat 828 (produced by Yuka Shell Epoxy Co., Ltd.) 100 parts Methylhexahydrophthalic anhydride 85 parts Triethanolamine 5 parts The above components were mixed by stirring to obtain a resin composition. The resin composition thus obtained was cured at 100 ° C. for 2 hours, the curing exothermic temperature was measured, and further cured at 150 ° C. for 2 hours to obtain a cured resin product.

(Example 3) Epicoat 828 (produced by Yuka Shell Epoxy Co., Ltd.) 100 parts Methylhexahydrophthalic anhydride 85 parts Triethanolamine 5 parts Benzyldimethylamine 1 part The above components are stirred and mixed to form a resin composition. I got a thing. The obtained resin composition was cured at 80 ° C. for 2 hours, the curing exothermic temperature was measured, and further cured at 150 ° C. for 2 hours to obtain a resin cured product.

Example 4 Epicoat 828 (produced by Yuka Shell Epoxy Co., Ltd.) 100 parts Methylhexahydrophthalic anhydride 85 parts Triethanolamine 3 parts 2 Ethyl 4-methylimidazole 0.5 parts The above components are mixed by stirring. Then, a resin composition was obtained. The obtained resin composition was cured at 80 ° C. for 2 hours, the curing exothermic temperature was measured, and further cured at 150 ° C. for 2 hours to obtain a resin cured product.

Comparative Example 1 Epicoat 828 (produced by Yuka Shell Epoxy Co., Ltd.) 100 parts Methylhexahydrophthalic anhydride 85 parts Benzyldimethylamine 1 part The above components were mixed by stirring to obtain a resin composition. The resin composition thus obtained was cured at 100 ° C. for 2 hours, the curing exothermic temperature was measured, and further cured at 150 ° C. for 2 hours to obtain a cured resin product.

Comparative Example 2 Epicoat 828 (manufactured by Yuka Shell Epoxy Co., Ltd.) 100 parts Methylhexahydrophthalic anhydride 85 parts Benzyldimethylamine 1 part The above components were stirred and mixed to obtain a resin composition. The obtained resin composition was cured at 80 ° C. for 2 hours, the curing exothermic temperature was measured, and further cured at 150 ° C. for 2 hours to obtain a resin cured product.

Comparative Example 3 Epicoat 828 (manufactured by Yuka Shell Epoxy Co., Ltd.) 100 parts Methylhexahydrophthalic anhydride 85 parts 2 Ethyl 4-methylimidazole 0.5 parts Resin composition by stirring and mixing the above components Got The obtained resin composition was cured at 80 ° C. for 2 hours, the curing exothermic temperature was measured, and further cured at 150 ° C. for 2 hours to obtain a resin cured product.

Comparative Example 4 Epicoat 828 (produced by Yuka Shell Epoxy Co., Ltd.) 100 parts Diethylenetriamine 8 parts The above components were mixed by stirring to obtain a resin composition. The obtained resin composition was cured at 100 ° C. for 1 hour, and the curing exothermic temperature was measured to obtain a cured resin product.

The characteristics of the resin compositions obtained in these Examples and Comparative Examples are shown in Table 1.

[0025]

[Table 1]

The pot life is the time until the initial viscosity reaches twice at 25 ° C., and the glass transition temperature is JIS.
K7121 method, bending strength and Charpy impact strength are JIS C2105 method, C washer test is 7
20 g of epoxy resin composition is cast into a Φ mold, and SU
Enclose a 12Φ C washer made of S304 and put it under predetermined curing conditions in cold water of 0 ° C. and boiling water of 100 ° C. alternately for 5 minutes each, and the number of cycles until the cured product cracks. It is a test method evaluated by.

[0027]

As described above, the resin cured product obtained by using the epoxy resin composition in the present invention has no deterioration in crack resistance due to the residual strain generated at the time of curing, and the bending strength and the impact strength. The mechanical properties represented by
It is extremely useful as a resin for encapsulation of electric and electronic parts.

Claims (1)

[Claims] 1. An epoxy resin composition comprising an epoxy resin which is liquid at room temperature and an acid anhydride curing agent which is liquid at room temperature, containing an alkanolamine represented by the general formula (1) or (2). An epoxy resin composition characterized by the above. [Chemical 1] (In the formula, n is an integer of 1 to 20) (In the formula, n: an integer of 1 to 20)