JPH0150249B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an epoxy resin composition having excellent properties as an electrically insulating material. Epoxy resin has excellent electrical properties, mechanical properties, and moisture resistance, so it is widely used as a highly reliable electrical insulating material for sealing and impregnating electrical and electronic components, and for laminated boards. Conventional epoxy resin compositions used as electrical insulating materials are made by curing epoxy resin and curing agents such as polyamines, acid anhydrides, or phenolic resins using tertiary amines or imidazoles as curing accelerators. This was the most common method.
However, these epoxy resin compositions had the following drawbacks. (1) Electrical properties deteriorate rapidly at high temperatures, especially at temperatures above 150°C. (2) Reliability decreases in high temperature and high humidity environments. (3) Insufficient latent curing properties. Recently, there have been strict requirements for the reliability of electrical parts at high temperatures, and therefore epoxy resin compositions used as materials for electrical parts are required to satisfy these demands. It was difficult to satisfy the electrical characteristics at high temperatures. The same goes for moisture resistance.The level of moisture resistance required of electrical parts is becoming higher and higher, and it has been difficult for conventional epoxy resin compositions to satisfy these requirements. In addition, in terms of workability and ease of use, conventional compositions do not have sufficient latent curing properties, and the curing reaction proceeds at a considerable rate even at room temperature, so they cannot withstand long-term storage. It was hot. An object of the present invention is to improve the drawbacks of conventional epoxy resin compositions and to provide an epoxy resin composition having excellent high-temperature electrical properties, moisture resistance, and latent curability. In order to achieve the above object, the inventors of the present invention have conducted extensive research and have found that the following epoxy resin composition has superior electrical properties, moisture resistance, and latent curing properties compared to conventional epoxy resin compositions. It has been found that the composition is based on That is, the present invention comprises (a) an epoxy resin, (b) a curing agent for an epoxy resin having two or more phenolic hydroxyl groups in one molecule, (c) an organic phosphine compound as a curing accelerator, and (d) a metal chelate compound. Then, it is an epoxy resin composition characterized by comprising (e) an inorganic filler as an essential component. The epoxy resin that can be used in the present invention is commonly known and is not particularly limited. For example, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, such as bisphenol A type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, etc.
Examples include epoxy resins having two or more epoxy groups in one molecule, such as glycidylamine type epoxy resins, linear aliphatic epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, and halogenated epoxy resins. However, these epoxy resins may be used alone or in a mixed system of two or more. Additionally, these epoxy resins have a chlorine ion content of 10ppm.
Below, it is desirable that the content of hydrolyzable chlorine is 0.1% by weight or less. Among the above epoxy resins, glycidyl ether type epoxy resins are most preferred;
In particular, the most excellent properties can be obtained when a novolac type epoxy resin having an epoxy equivalent of 170 to 300 is used. Curing agents for epoxy resins having two or more phenolic hydroxyl groups in one molecule that can be used in the present invention include phenolic resins and polyphenol compounds, and specific examples include phenol novolac resins, cresol novolac resins, These include novolak-type phenolic resins such as tert-butylphenol novolak resin and nonylphenol novolac resin, and resol-type phenolic resins and bisphenol A. Among these, novolak type phenolic resins are most preferred. Further, the softening point of the resin is preferably within the range of 60°C to 120°C, and it is further preferable that the content of the water-soluble phenol resin component at room temperature is 3% or less. In the present invention, regarding the compounding ratio of the epoxy resin and the curing agent, the ratio of the number of phenolic hydroxyl groups in the curing agent to the number of epoxy groups in the epoxy resin is 0.5 to 1.5.
Preferred characteristics can be obtained by blending the curing agent and epoxy resin within the ranges of . More preferable properties can be obtained when the ratio of the number of phenolic hydroxyl groups to the number of epoxy groups is within the range of 0.8 to 1.2. The organic phosphine compound particularly used as a curing accelerator in the present invention has the chemical formula []
in There are tertiary phosphine compounds in which R ₁ to _{R 3} are all organic groups, secondary phosphine compounds in which only R ₃ is hydrogen, and primary phosphine compounds in which R ₂ and R ₃ are both hydrogen. Specifically, triphenylphosphine, tributylphosphine, tricyclohexylphosphine, methyldiphenylphosphine, butylphenylphosphine, diphenylphosphine,
These include phenylphosphine and octylphosphine. Further, R ₁ may be an organic group containing an organic phosphine. For example, bisorganophosphine compounds such as bis(1,2-diphenylphosphino)ethane and bis(diphenylphosphino)methane are used. Among these, organic tertiary phosphine compounds are preferred, and triphenylphosphine, bis(1,2-diphenylphosphino)ethane, bis(diphenylphosphino)methane, and the like are particularly preferred. Further, these organic phosphine compounds may be used alone or in a mixed system of two or more. However, the composition ratio of the organic phosphine compound of the lever may generally be within the range of 0.01 to 20% by weight of the resin content (epoxy resin and curing agent), but particularly preferable properties are 0.01 to 20% by weight.
Obtained within 5.0% by weight. In the present invention, by using a metal chelate compound, the properties of the epoxy resin composition as an electrical insulating material are improved by the interaction between the metal chelate compound and the organic phosphine compound, compared to when the organic phosphine compound is used alone. can be significantly improved. The metal chelate compound used in the present invention is not particularly limited. To give specific examples, metals that form chelate compounds include aluminum, barium, calcium, cadmium, cobalt, chromium, copper, iron, potassium, magnesium,
Examples include manganese, sodium, nickel, lead, palladium, rhodium, titanium, vanadium, zinc, and zirconium. Ligands include acetylacetone, ethyl acetoacetate, glycine, salicylaldehyde, 8-oxyquinoline,
Ethylenediamine, triethylenetetramine, ethylenediaminetetraacetic acid, salicylic acid, oxalic acid,
Examples include dimethylglyoxime, dipyridyl, and phenanthroline. The epoxy resin composition according to the present invention comprises (a) an epoxy resin, (b) a curing agent for an epoxy resin having two or more phenolic hydroxyl groups in one molecule, (c) an organic phosphine compound, and (d) a metal chelate compound. Although the composition may be composed of only the four components (e), an epoxy resin composition with improved properties and workability can be obtained by adding and blending (e) an inorganic filler. Particularly when used as a molding material, it is effective in improving thermomechanical properties. Specific examples of inorganic fillers include quartz glass powder, crystalline silica powder, glass fiber, talc, alumina powder, calcium silicate powder, calcium carbonate powder, barium sulfate powder, and magnesia powder. Most preferred are glass powder and crystalline silica powder. However, the composition ratio of these inorganic fillers varies depending on the application, the resin content (epoxy resin and epoxy resin curing agent), and the type of inorganic filler. For example, when used in transfer molding, 150 to 100 parts by weight of resin
About 400 parts by weight is sufficient. Furthermore, when used in transfer molding, a molding material with good properties can be produced by appropriately selecting the particle size distribution of the inorganic filler. The epoxy resin composition according to the present invention can be used as necessary, for example, natural waxes, synthetic waxes,
Mold release agents such as metal salts of straight chain fatty acids, acid amides, esters or paraffins, chlorinated paraffins, bromotoluene, hexabromobenzene,
A flame retardant such as antimony trioxide, a coloring agent such as carbon black, a silane coupling agent, etc. may be appropriately added and blended. A general method for preparing the epoxy resin composition according to the present invention as a molding material is to thoroughly mix the raw material components selected at a predetermined composition ratio using, for example, a mixer, and then melt-mix using hot rolls. An epoxy resin molding material can be easily obtained by processing or mixing using a kneader or the like. Next, embodiments of the present invention will be described. Example Phenol novolac type epoxy resin with epoxy equivalent weight 200 (epoxy resin A), epoxy equivalent weight 400
Bisphenol A type epoxy resin (epoxy resin B), phenol novolac resin curing agent with molecular weight 700, methylnadic anhydride, triphenylphosphine, tris(acetylacetonato)aluminum, bis(dimethylglyoximate)nickel, ethylenediamine Six types of epoxy resin compositions, including a comparative example, were prepared by selecting cobalt tetraacetate and benzyl dimethylamine in the composition ratios (parts by weight) shown in Table 1. Using the above epoxy resin composition as an electrically insulating coating material, coating an aluminum electrode formed on an insulating plate with a thickness of 1 mm,
It was cured by heating at 180°C for 8 hours. To investigate the electrical properties of coated insulating films at high temperatures
The volume resistivity was measured after being left at 150°C for 1 hour. If this measured value was 1×10 ¹³ Ω·cm or less, it was determined to be defective, and the defect rate for each of the 20 test samples is shown in Table 2. Next, in order to examine the moisture resistance of the coated insulating film,
The samples were allowed to stand for a period of time, and the presence or absence of corrosion of the aluminum electrodes was detected, and samples with corrosion were determined to be defective. The results are shown in Table 3. The test samples are 20 pieces each.

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【table】

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[Table] Examples 4 to 6 Cresol novolak type epoxy resin with epoxy equivalent weight 220 (epoxy resin C), epoxy equivalent weight 370
alicyclic epoxy resin (epoxy resin D), brominated epoxy novolac resin (epoxy resin E) with an epoxy equivalent of 290, phenol novolac resin curing agent with a molecular weight of 800, tetrahydrophthalic anhydride curing agent, triphenylphosphine, Tris(acetylacetonate)aluminum, diglycinate palladium, disalicylaldehyde copper, 2-phenylimidazole, crystalline silica powder, montan wax, carbon black, antimony trioxide in the composition ratios shown in Table 4 (by weight). Part), and six types of epoxy resin compositions were prepared, including a comparative example. The above compositions were prepared by kneading the respective selected components with heated rolls, cooling and pulverizing them to obtain epoxy resin molding materials. An electrical component with two aluminum wirings deposited on an alumina substrate using the above molding material.
Transfer mold at 180℃ for 3 minutes, then
Post-curing was carried out at 180°C for 8 hours. For each 50 resin-sealed electrical components obtained in this way, 120
Table 5 shows the results of a moisture resistance test to investigate corrosion of aluminum wiring by applying 2V in high-pressure steam at ℃.
It was shown to. Furthermore, in order to investigate the electrical characteristics at high temperatures, 50 of each of the above resin-sealed electrical components were left at 150℃ for 1 hour, and then 100V was applied between the two aluminum wires.
and measure the leakage current between the wires, and check if the leakage current is 1
Table 6 shows the results of examining the defective rate by determining that ×10 ^-11 A or more is defective.

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[Table] Furthermore, in order to investigate the latent curing property, the storage life was examined by leaving it at room temperature, and the pot life of Example 4 was 5 weeks, and the pot life of Comparative Example 4 was 1 week. Example 7 The same materials used in Examples 4-6 and tetrakis(acetylacetonato)zirconium,
Using a silane coupling agent (γ-glycidoxypropyltrimethoxysilane), four types of compositions, including a comparative example, having the compositions shown in Table 7 (parts by weight) were prepared to prepare molding materials. The same electrical components as those used in Examples 4 to 6 were sealed using this molding material, and a moisture resistance test was conducted. The sealing and testing conditions are the same as Examples 4-6. The results are shown in Table-8.

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[Table] Comparative Example The same materials as those used in Examples 4 to 7 and other curing accelerators used in combination include 2-phenylimidazole, benzyldimethylamine, tris(dimethylaminomethyl)phenol, piperidine,
Comparative examples having the compositions (parts by weight) shown in Table 9 were prepared using each of BF ₃ monoethylamine. Using these comparative examples, a reliability evaluation test was conducted under exactly the same conditions as in Example 7, and the results are shown in Table 10.

【table】

[Table] As is clear from the above comparative examples, when other curing accelerators are used in combination with the organic phosphine compound instead of the metal chelate compound, the effects of the present invention cannot be obtained. In addition, as is clear from comparing Comparative Examples 10 to 14 with the aforementioned Comparative Example 7, by using a curing accelerator other than the metal chelate compound in addition to the organic phosphine compound, the organic phosphine It can be seen that the moisture resistance of the compound was significantly reduced, making it unsuitable for use as a sealing resin composition. As described above, the epoxy resin composition of the present invention, which is formed by using two specific substances in combination, has excellent properties and can be used in a wide range of electrical component materials.

Claims (1)

[Claims] 1 (a) an epoxy resin (b) a curing agent for an epoxy resin having two or more phenolic hydroxy acids in one molecule, (c) an organic phosphine compound, and (d) a metal chelate compound as essential components An epoxy resin composition characterized by comprising: 2 (a) Epoxy resin (b) Hardening agent for epoxy resin having two or more phenolic hydroxyl groups in one molecule (c) Organic phosphine compound (d) Metal chelate compound and (e) Inorganic filler as essential components An epoxy resin composition characterized by comprising: