JPH0748501A - Epoxy resin composition for electronic component - Google Patents

Abstract

PURPOSE:To obtain the composition low in stimulative properties and excellent in curability, safety, filler dispersibility, etc., by using an epoxy resin and a cyclic alkyl carbonate compound as the essential components. CONSTITUTION:An epoxy resin such as a bisphenol A-derived epoxy resin or. a bisphenol F-derived epoxy resin is mixed with a cyclic alkyl carbonate compound such as ethylene carbonate or propylene carbonate as the essential components to produce the composition for electric and electronic components. The mixing ratio is suitably such that about 5-30 pts.wt. cyclic alkyl carbonate compound is used per 100 pts.wt. epoxy resin. This composition can be cured with a curing agent such as an acid anhydride (e.g. phthalic anhydride), is desirable for sealing especially a transformer and can provide a casting product excellent in durability.

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 electric / electronic parts, particularly for encapsulating transformers and the like.

[0002]

2. Description of the Related Art Epoxy resin is widely used as an insulating agent for electric and electronic materials because of its good electrical characteristics, mechanical properties and adhesiveness, but it is especially used for the insulation treatment of flyback transformers and ignition coils. When it is used for impregnation casting, it is necessary to blend a large amount of an inorganic filler having high thermal conductivity in order to improve mechanical properties and heat dissipation in addition to insulation performance, impregnation property and crack resistance.

However, when a large amount of the filler is blended, the viscosity of the composition rises and the impregnating property deteriorates. Further, the filler settles during the curing reaction, and only a non-uniform cast product is obtained. Therefore, in addition to devising the particle size of the filler, a specific reactive diluent, such as butyl glycidyl ether, has been used for the purpose of reducing the viscosity of the resin and increasing the dispersibility of the inorganic filler to suppress sedimentation ( Japanese Patent Laid-Open No. 59-1598
19 publication).

[0004]

Recently, however, such a low-molecular-weight glycidyl ether has a mutagenic property, and it has become a problem that special attention must be paid to the working environment. There is. Further, since glycidyl ethers contain a large amount of organic chlorine compounds as impurities due to their production method, there is a reliability problem that they corrode the metal part of the sealed electronic component.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies in order to develop an epoxy resin composition suitable for sealing or adhering electric and electronic parts which can solve the above problems. As a result, they have found that the object can be achieved by using a cyclic alkyl carbonate compound, and have completed the present invention based on this finding.

That is, the present invention provides an epoxy resin composition for electrical / electronic encapsulation parts, which comprises (A) epoxy resin (B) cyclic alkyl carbonate compound. Less than,
The present invention will be specifically described.

Examples of the epoxy resin (A) include bisphenol A, bisphenol F, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, biphenol, dihydroxynaphthalene, hydroquinone and resorcinol. Such as 2
Epoxy resins obtained by reaction of trihydric phenols with epichlorohydrin; Epoxy resins obtained by reaction of trihydric phenols such as trisphenolmethane and benzenetriol with epichlorohydrin; Phenol novolac resins, cresol novolac resins There are epoxy resins obtained by the reaction of polyhydric phenols with epichlorohydrin.

Of these, epoxy resins obtained by reacting dihydric phenols with epichlorohydrin are preferred, and epoxy equivalents of 100 to 40 are particularly preferred.
It is an epoxy resin having a relatively low degree of polymerization of 0 g / eq, and such an epoxy resin has an epoxy equivalent of 1
There are 60 to 200 g / eq of bisphenol A type epoxy resin and bisphenol F type epoxy resin.

These epoxy resins have an epoxy group of α
The compound that has become a glycol may contain 10 to 200 meq / Kg as an α-glycol group. Further, a compound in which an epoxy group becomes a chlorohydrin group may be contained as a chlorine atom in an amount of 1 to 1500 ppm.

The cyclic alkyl carbonate compound (B) is a cyclic alkylene carbonate containing one 1,2-carbonate group, and a preferred alkylene chain contains 2 to 10 carbon atoms, and the alkylene chain is a straight chain. It may be chained or branched.

For example, ethylene carbonate, propylene carbonate,
1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-hexylene carbonate, 1,2-
Heptylene carbonate may be mentioned, but particularly preferred cyclic alkyl carbonate compounds are ethylene carbonate and propylene carbonate.

The amount of the cyclic alkyl carbonate compound used in the composition of the present invention is an amount sufficient to make the viscosity of the epoxy resin easy to use according to the use conditions, and is not substantially preferable for the physical properties of the cured product. The amount has no effect.

Generally, in order to reduce the viscosity by adding a cyclic alkyl carbonate compound, epoxy resin 100 is used.
At least 1 part by weight of cyclic alkyl carbonate compound is required with respect to parts by weight. On the other hand, if the addition amount exceeds a certain amount, the crosslink density becomes low, which causes deterioration of cured physical properties.
The amount is generally 80 with respect to 100 parts by weight of the epoxy resin.
Parts by weight.

For cast-in-sealing applications, it is usually desirable that the curable composition have a viscosity of about 200 to 400 poise at room temperature. Therefore, it is desirable that the cyclic alkyl carbonate compound is used in an amount of about 1 to 50 parts by weight, particularly 5 to 30 parts by weight, based on 100 parts by weight of the resin.

In the present invention, an epoxy resin composition is obtained by using the above (A) and (B). The order of mixing may be either (A) with (B) or vice versa. The mixing temperature may be any number as long as it is a temperature at which mixing is possible.

The epoxy resin compounded as described above can be cured using any known curing agent. That is, polyamine-based, acid anhydride-based, Lewis acid-based,
The curing agent can be arbitrarily selected from Lewis bases and the like according to the purpose of use.

Specific examples of the polyamine-based curing agent include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine, metaphenylenediamine, metaxylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, Examples include adipic acid dihydrazide and polyamide polyamine. Mannich bases composed of these amines, phenol and formalin, and ketimines composed of acetone can also be preferably used.

Specific examples of the acid anhydride type curing agent include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride and methylanhydride. Examples include nadic acid, dodecyl succinic anhydride, chlorendic acid anhydride, pyromet acid anhydride, and trimellitic acid anhydride.

Specific examples of Lewis acid type curing agents include boron trifluoride monoethylamine complex, and specific examples of Lewis base type curing agents include 2 ethyl 4-methyl imidazole, 2,4,6-tris (dimethyl). Methylamine) phenol, etc. Further, a heat-curable curing agent microencapsulated as a latent curing agent, a heat / light-curable latent curing agent composed of an aluminum complex and an active silicon compound, diphenyliodonium tetrafluoroborate, triphenylsulfonium tetrafluoroborate, triphenylselenium. A photo-curable type such as tetrafluoroborate can be used.

The amount of the curing agent used for curing is appropriately determined according to the end use, but is 0.5 to 2.0 amine hydrogen based on the epoxy group and carbonate group contained in the epoxy resin composition. Alternatively, a curing agent is used in such an amount that it becomes an acid anhydride group. In the case of Lewis acid or Lewis base system, a catalytic amount is sufficient.

If necessary, a filler such as hydrated alumina, silicon oxide powder or calcium carbonate; a pigment such as titanium oxide or chromium oxide; a plasticizer such as polyethylene glycol or rubber; a silane coupling agent or a titanium cup. A surface treatment agent such as a ring agent; a curing accelerator such as 2-ethyl-4-methylimidazole or triphenylphosphine can be added.

The curing conditions vary depending on the type of curing agent used and the purpose of use, but curing can be carried out at a temperature of 0 ° C to 200 ° C.

[0023]

The present invention is described in detail below with reference to examples, but these do not limit the scope of the present invention. (Example 1) Bisphenol A diglycidyl ether type liquid epoxy resin (epoxy equivalent 189, viscosity at 25 ° C 1,380 cps, α-glycol concentration 65 me
15 g of propylene carbonate was added to 85 g of q / Kg and hydrolyzable chlorine of 300 ppm) and mixed well at room temperature to obtain an epoxy resin composition. When this composition was subjected to a mutagenicity test, it was negative. 200 g of silicon oxide powder (silica crystallite C66), calcium carbonate 6
0 g was added and kneaded with a three-roll mill. Further, 80 g of tetrahydrophthalic anhydride was used as a curing agent, and 2-g
2 g of ethyl-4-methylimidazole was added and mixed. Casting was performed using this compounded product and cured at 100 ° C. for 2 hours and further at 150 ° C. for 3 hours. Then, the physical property test of the cured product and the evaluation of the cast product were carried out. The results are shown in Table 1.

Example 2 Bisphenol F diglycidyl ether type liquid epoxy resin as epoxy resin (epoxy equivalent 170, viscosity at 25 ° C. 3,000 cp)
A cured product and a cast product were obtained and evaluated in the same manner as in Example 1 except that s, α-glycol concentration of 30 meq / Kg, hydrolyzable chlorine of 300 ppm) of 90 g, and propylene carbonate of 10 g were used. The results are shown in Table 1.

(Example 3) Epoxyphenol novolac type epoxy resin (epoxy equivalent 1
Viscosity at 75 and 52 ° C 1,700 cps, α-glycol concentration 100 meq / Kg, hydrolyzable chlorine 300
(ppm) 80 g and propylene carbonate 20 g were used, and a cured product and a cast product were obtained in the same manner as in Example 1 and evaluated.

Example 4 A cured product and a cast product were obtained and evaluated in the same manner as in Example 1 except that ethylene carbonate was used as the cyclic alkyl carbonate compound.

Comparative Example 1 A cured product and a cast product were obtained and evaluated in the same manner as in Example 1 except that butyl glycidyl ether was used instead of propylene carbonate. When a composition of butyl glycidyl ether and the epoxy resin was subjected to a mutagenicity test, it was positive. The results are shown in Table 1 below.

[0028]

[Table 1]

* 1 Measured with a B type viscometer. * 2 After cast-curing to a depth of 10 cm, ash the top and bottom 1 cm of the cured product and measure the weight of the residue.
The difference between the top and bottom was calculated. The larger the difference, the greater the sedimentation property. * 3 A model coil in which an enamel wire with a diameter of 0.05 mm is wound 300 turns on a modified PPO bobbin is cast, and after curing, the central part is cut and the impregnation rate of the resin composition between the windings is measured with a microscope. Observed at.

* 4 10 model capacitors were sealed with this compound and kept at 100 ° C for 2 hours, then 150 ° C.
Cured for 3 hours. This sealed capacitor is 12
The pressure cooker at 1 ° C. was used for 100 hours, and the number of broken wires was examined. The smaller the number, the higher the durability. * 5 The cured product was crushed, the organic matter was dispersed with fuming nitric acid, and then the contained Cl ⁻ ion was analyzed by ion chromatography.

[0031]

According to the present invention, by using a curable composition containing an epoxy resin and a cyclic alkyl compound for sealing electric parts and electronic parts, casting work can be performed in a good working environment and The cast product thus obtained has excellent cured physical properties and has durability superior to conventional products.

Claims (1)

[Claims] 1. An electric / electronic epoxy resin composition comprising (A) an epoxy resin and (B) a cyclic alkyl carbonate compound.