JP6143358B2 - One-part liquid epoxy resin composition - Google Patents

Description

The present invention relates to a one-component liquid epoxy resin composition for hermetically sealing or insulatingly sealing small electronic components such as relays or electrical components.

With the development of the electronics industry, the production volume of relays has been growing steadily, and there are a wide variety of fields such as communication equipment, OA equipment, home appliances, and vending machines. In particular, the number of relays mounted on printed wiring boards is increasing. Its necessary characteristics include prevention of solder flux penetration, solvent cleaning of parts, and airtightness after solder reflow treatment, etc., and the number of completely hermetically sealed relays made of resin and the like has increased. As a result, the reliability requirements are becoming stricter.

As described above, as the airtightness of the relay is strongly required, an excellent sealing material is required. Conventionally, as a sealing resin for such a purpose, an epoxy resin is used. It was used. The epoxy resin composition includes a so-called two-pack type epoxy resin composition in which a curing agent such as polyamidoamine or acid anhydride and an epoxy resin are mixed immediately before use, and dicyandiamide or the like as a latent curing agent in advance. There is a so-called one-component liquid epoxy resin composition that is mixed with the resin composition.

In general, the disadvantages of the two-pack type epoxy resin composition include poor curing due to measurement errors at the time of blending and short pot life after blending. Further, when polyamidoamine, aliphatic amine, or the like is used as the curing agent, the heat resistance of the cured product is low, and airtight failure after passing through the solder tank after sealing often occurs. Similarly, when an acid anhydride is used, there is a drawback that the curing temperature must be increased. Therefore, recently, there has been a shift to a one-component liquid epoxy resin composition with low material loss and high productivity.

Conventionally, a one-component liquid epoxy resin composition is an essential material for the production of electric and electronic parts because of its excellent electrical characteristics and heat resistance, and has been used as an adhesive and a sealant. In addition, since the constituent members of electric and electronic components are mainly plastic materials other than terminal materials, coils, magnets, etc., a curing temperature of 120 ° C. or lower is desired.

In recent years, with the reduction in size, weight and density of electric and electronic parts, the gaps between the bonding parts and the sealing parts of various parts have become very narrow, such as several μm or less. In extremely narrow gaps of several μm or less, separation between the liquid epoxy resin and the curing agent occurs due to capillary action, and the liquid epoxy resin separated from the curing agent penetrates to places such as moving parts and contact parts, resulting in poor contact. There has been a problem of causing characteristic defects such as.

As a means for solving the above problem, a one-component liquid epoxy resin composition that completely cures a portion that flows into a gap has been proposed (Patent Document 1). However, since the flow itself into a gap with a very narrow interval of several μm or less has not been improved, especially in a relay that requires hermetic sealing or insulation sealing, the gap to a gap with a very narrow interval of several μm or less is required. Development of a one-pack type liquid epoxy resin composition with reduced inflow has been strongly desired.

JP 2001-220429 A

The present invention relates to a one-component liquid epoxy resin composition having improved flow into gaps of very narrow intervals of several μm or less when small electronic parts or electrical parts such as relays are hermetically sealed or insulated. It provides things.

As a result of intensive studies on various one-component liquid epoxy resin compositions in order to achieve the above object,
(A) Epoxy resin (B) Dicyandiamide (C) Latent curing agent other than dicyandiamide (D) Calcium carbonate with resin acid treatment on the surface (E) Calcium carbonate with fatty acid treatment on surface (A) Epoxy By using a one-pack type epoxy resin composition characterized by containing 0.5 to 20 parts by weight with respect to 100 parts by weight of the resin, flow into gaps of extremely narrow intervals of several μm or less is improved. As a result, the present invention has been completed.

According to the present invention, basic physical properties as a one-component liquid epoxy resin composition including fluidity for hermetically sealing or insulating sealing small electronic components or electrical components such as relays are sacrificed. Instead, it is possible to provide a one-part liquid epoxy resin composition with improved flow into gaps of extremely narrow intervals of several μm or less.

The (A) epoxy resin used in the present invention is not particularly limited as long as it is an epoxy resin used in a one-part liquid epoxy resin composition, but is used in an epoxy resin composition for relay sealing. Epoxy resins are preferred. Specific examples of the epoxy resin used in the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, dicyclopentadiene. Type epoxy resin, polyhydric phenols such as catechol and resorcin, polyglycidyl ethers obtained by reacting polyhydric alcohols such as glycerin and polyethylene glycol with epichlorohydrin, or hydroxycarboxylic acids such as p-oxybenzoic acid and epichlorohydrin Glycidyl ether ester obtained by reacting glycidyl ether, or polyglycidyl ester obtained from polycarboxylic acid such as phthalic acid or terephthalic acid, or 4,4-diaminodiphenyl Glycidylamine epoxy resins obtained from such tank and m- aminophenol, further include phenol novolac type epoxy resin or the like. Among these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and glycidylamine type epoxy resin are preferably used. These epoxy resins may be used alone or in combination.

(D) Calcium carbonate whose surface has been subjected to resin acid treatment (hereinafter sometimes referred to as resin acid-treated calcium carbonate) used in the present invention refers to calcium carbonate surface-treated with resin acids. The resin acid-treated calcium carbonate may have a structure that covers all or part of the surface of the raw material calcium carbonate particles or the treated calcium carbonate particles with resin acids, and it is not always necessary to continuously cover the entire surface. Absent. Further, the processing order is not limited.

Known calcium carbonate, synthetic (precipitating) calcium carbonate, or the like can be used as the calcium carbonate that is a raw material for the resin acid-treated calcium carbonate. Examples of the resin acids include abietic acids such as abietic acid, dehydroabietic acid, and dihydroabietic acid or polymers thereof, disproportionated rosin, hydrogenated rosin, polymerized rosin, and salts thereof (for example, alkali metal salts, alkalis) Earth metal salts) or esters.

There is no restriction | limiting in particular in the surface treatment method of the calcium carbonate by a resin acid, A well-known processing method can be used. Although there is no restriction | limiting in particular in the adhesion amount of resin acid, 5-30 mass parts is preferable with respect to 100 mass parts of calcium carbonate used as a raw material, and 10-20 mass parts is more preferable. The average particle diameter of the resin acid-treated calcium carbonate is preferably 0.01 to 20 μm, and more preferably 0.02 to 15 μm.

For example, commercially available grades of resin acid-treated calcium carbonate can be used. Specifically, “Shirakaka DD”, “IGV-IV”, etc. manufactured by Shiroishi Calcium Co., Ltd. are exemplified. Moreover, although it does not specifically limit as the usage-amount of the calcium carbonate which performed resin acid treatment on the (D) surface, Usually, (A) resin acid treatment was performed on the surface with respect to 100 weight part of epoxy resins. 1 to 35 parts by weight, preferably 5 to 30 parts by weight of calcium carbonate is used. When the amount used is less than 1 part by weight, the epoxy resin may flow into gaps of extremely narrow intervals of several μm or less, and the effect of the present application may not be exhibited. When the amount is more than 35 parts by weight, there is a possibility that an insoluble component may be generated when the one-component liquid epoxy resin composition is used, and this may cause inconvenience in the manufacturing process. Therefore, there is a possibility that the one-pack type liquid epoxy resin composition cannot be produced industrially.

The calcium carbonate whose surface is treated with fatty acid (E) used in the present invention (hereinafter sometimes referred to as fatty acid-treated calcium carbonate) refers to calcium carbonate whose surface is treated with fatty acids. The fatty acid-treated calcium carbonate may have a structure that covers all or part of the surface of the raw material calcium carbonate particles or the treated calcium carbonate particles with fatty acids, and does not necessarily need to continuously cover the entire surface. . Further, the processing order is not limited.

Known calcium carbonate, synthetic (precipitating) calcium carbonate, or the like can be used as the calcium carbonate that is a raw material for the fatty acid-treated calcium carbonate. Examples of the fatty acids include caproic acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, oleic acid, maleic acid, linoleic acid, Examples include fatty acids such as linolenic acid, adipic acid, hydroxy fatty acid, beef tallow fatty acid, coconut fat fatty acid, tall oil fatty acid and the like.

The surface treatment method of calcium carbonate with a fatty acid is not particularly limited, and a known treatment method can be used. Although the adhesion amount of a fatty acid is not particularly limited, 1 to 15 parts by mass is preferable with respect to 100 parts by mass of calcium carbonate as a raw material. The average particle diameter of the fatty acid-treated calcium carbonate is preferably 0.01 to 20 μm, and more preferably 0.02 to 15 μm.

As the above-described fatty acid-treated calcium carbonate, for example, a commercially available grade can be used. Specific examples include “Miclone 200” manufactured by Yonesho Lime Industry Co., Ltd., “Shiraka Hana CC” manufactured by Shiraishi Calcium Co., Ltd., and the like. Moreover, (E) calcium carbonate which performed the fatty acid process on the surface uses 0.5-20 weight part of (E) calcium carbonate which performed the fatty acid process on the surface with respect to 100 weight part of epoxy resins. When the amount used is less than 0.5 parts by weight or more than 20 parts by weight, when the epoxy resin composition is applied to an object, it is difficult to apply due to excessive flow or too high viscosity. The problem of use, such as becoming.

As (B) dicyandiamide used in the present invention, those generally available can be used, and among them, those pulverized in advance and passed # 150 mesh are preferred. (B) When dicyandiamide is not added, the adhesiveness with the metal is lowered, and it becomes impossible to hermetically seal or insulate the small electronic component or electrical component. Moreover, the usage-amount is although it does not specifically limit, Usually, 1-10 weight part with respect to 100 weight part of (A) epoxy resins, Preferably 1-5 weight part is used. If the amount is less than 1 part by weight, the adhesion to the metal may be lowered. If the amount is more than 10 parts by weight, the adhesiveness to the resin is lowered and the practicality as a one-part liquid epoxy resin composition becomes poor. There is a fear.

Examples of the latent curing agent other than (C) dicyandiamide used in the present invention include an epoxy resin imidazole adduct compound, an epoxy resin amine adduct compound, a modified aliphatic polyamine compound, and a hydrazide compound. Among these, an epoxy resin imidazole adduct compound, an epoxy resin amine adduct compound, and a modified aliphatic polyamine compound are preferably used. Specific examples of such compounds include epoxy resin imidazole adduct compounds, such as Ajinomoto Technofine Co., Ltd. Amicure PN-23, Amicure PN-R, Air Product Japan Co., Ltd. Sunmide LH-210, and the like. Examples of the epoxy resin amine adduct compound include Amicure MY-24, Amicure MY-R manufactured by Ajinomoto Technofine Co., Ltd., and adduct compounds disclosed in JP-A No. 57-1000012. Examples of the modified aliphatic polyamine compound include Fujicure FXE-1000 and Fujicure FXR-1121 manufactured by T & K TOKA. Further, the amount of the latent curing agent other than (C) dicyandiamide is not particularly limited, but is usually 0.5 to 30 parts by weight, preferably 3 parts by weight per 100 parts by weight of (A) epoxy resin. 20 parts by weight from the part. (C) When a curing agent other than dicyandiamide is not blended, it is not cured at 120 ° C. or less, and when it is more than 30 parts by weight, the adhesiveness is lowered and the storage stability may be deteriorated.

The epoxy resin composition of this invention can mix | blend an inorganic filler, a coupling agent, a coloring agent, etc. as needed. Examples of the inorganic filler include calcium carbonate, barium sulfate, fused silica, crystalline silica, glass filler, aluminum hydroxide, magnesium hydroxide, and alumina. Examples of the coupling agent include 3-glycidoxypropyl. Examples include trimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane, and examples of the colorant include carbon black and titanium oxide.

Furthermore, the epoxy resin composition of this invention can mix | blend a thixotropic agent as needed. Examples of the thixotropic agent include Aerosil 130, Aerosil 200, Aerosil 300, Aerosil 380, Dispalon C-308, Disparon 4110, Disparon 4300, Disparon 6500, Disparon 6600, and the like manufactured by Nippon Aerosil Co., Ltd. It is done.

In the preparation method of the one-component liquid epoxy resin composition of the present invention, a general stirring and mixing apparatus and mixing conditions are applied in the same manner as in the preparation method of a normal epoxy resin composition. Examples of the apparatus used include a mixing roll, a dissolver, a planetary mixer, a kneader, and an extruder. As mixing conditions, epoxy resin or the like may be dissolved and / or reduced in viscosity, and heated to improve stirring and mixing efficiency. Further, cooling may be performed as necessary in order to remove frictional heat generation, reaction heat generation, and the like. The time for stirring and mixing may be determined if necessary, and is not particularly limited.

The one-component liquid epoxy resin composition produced in this way is cured at 120 ° C. or less and has fluidity suitable for workability, so that small electronic parts or electrical parts such as relays are hermetically sealed or insulated. It is suitably used for sealing. In addition, the fluidity | liquidity in this invention is defined by the value of 45 degree | times fluidity | liquidity measured on the conditions mentioned later. When the one-pack type liquid epoxy resin composition is used for the purpose described above, the 45 degree fluidity is preferably 10 to 25 mm. In the case of 25 mm or more, when the one-pack type liquid epoxy resin composition is applied to an object, the fluidity is too high to be applied, and in the case of 10 mm or less, the viscosity is too high to be applied. There is a risk of problems such as use.

<Measurement of 45 degree fluidity>
For each one-component liquid epoxy resin composition prepared in each of the examples and comparative examples described below, 100 mg of the one-component epoxy resin composition is accurately placed on the end of a slide glass (length 26 mm × width 76 mm × thickness 1.5 mm). And placed in a hot-air circulating drier set at 100 ° C. for a predetermined time at an inclination angle of 45 degrees. After removal, the flow distance (mm) is measured with a caliper.

<Measurement method of separation flow distance>
1. A spacer having a thickness of 9 μm is sandwiched between two opposing sides of 26 mm between two slide glasses (length 26 mm × width 76 mm × thickness 1.5 mm), and both ends thereof are clipped from above the slide glass.
2. 1. The one-component epoxy resin compositions prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were evenly applied to the 76 mm sides of the two glass slides, cured at 100 ° C. for 60 minutes, and then into the gaps. The maximum distance entered was measured. The evaluation criteria for the inflow distance are as follows.
Flow distance (mm):
×: More than 5.0, ○: 3.0 to 5.0, ◎: Less than 3.0

<Confirmation of residue after filtration>
Each one-component liquid epoxy resin composition prepared in each of Examples and Comparative Examples described later is naturally filtered through a 48-mesh net, and visually confirmed whether or not residues such as inorganic filler remain on the net. If the residue remains, the physical properties of the one-component liquid epoxy resin composition after filtration will not be greatly affected, but problems such as the production line stopping during production may develop.

<Example 1>
(A) D. As an epoxy resin E. R. 331J (bisphenol A type epoxy resin: manufactured by Dow Chemical Co., Ltd.) 75 parts by weight and jER807 (bisphenol F type epoxy resin: manufactured by Japan Epoxy Resin Co., Ltd.) 25 parts by weight, (B) Dicyandiamide 2.5 parts by weight , (C) Fujicure FXR-1121 (modified alicyclic polyamine compound: manufactured by T & K TOKA Co., Ltd.) as a latent curing agent other than dicyandiamide, (D) White Glossy DD as calcium carbonate subjected to resin acid treatment (Rosinic acid-treated calcium carbonate: manufactured by Shiraishi Calcium Co., Ltd.) 5 parts by weight, (E) Fatty acid-treated calcium carbonate mixed with Miclone 200 (Fatty acid-treated calcium carbonate: New Lime Co., Ltd.) 15 parts by weight, and then a mixing roll Were used for kneading to prepare a one-pack type liquid epoxy resin composition. Table 1 shows the results of checking and evaluating the 45-degree fluidity, the measurement of the flow-in distance, and the residue after filtration of these one-part liquid epoxy resin compositions.

<Example 2>
(D) The one-pack type epoxy resin composition was adjusted in the same manner as in Example 1 except that the calcium carbonate subjected to the resin acid treatment was changed from Shiroka Hana DD to IGV-IV (manufactured by Shiraishi Calcium Co., Ltd.). Table 1 shows the results of measuring the flow-in distance and confirming and evaluating the residue after filtration.

<Examples 3 to 5>
The amount of calcium carbonate subjected to resin acid treatment in Example 1 was changed from 5 parts by weight to 15 parts by weight, 30 parts by weight or 40 parts by weight, and (E) the blend of calcium carbonate subjected to fatty acid treatment. Except for changing the amount from 15 parts by weight to 10 parts by weight, 3 parts by weight or 1 part by weight, the one-pack type epoxy resin composition was adjusted in the same manner as in Example 1 to measure the fluidity at 45 degrees, the inflow distance, and after filtration. Table 1 shows the results of confirmation and evaluation of the residues.

<Comparative Example 1>
The result of having measured and evaluated 45 degree | times fluidity | liquidity and inflow distance by adjusting the one-pack type epoxy resin composition like Example 1 except not using calcium carbonate which performed resin acid treatment of (D) of Example 1. Is shown in Table 2.

<Comparative example 2>
A one-part epoxy resin composition was prepared and flowed at 45 degrees in the same manner as in Comparative Example 1, except that the calcium carbonate treated with (D) resin acid in Comparative Example 1 was changed to (E) calcium carbonate treated with fatty acid. Table 2 shows the results of measuring and evaluating the properties and the inflow distance.

<Comparative Example 3>
The one-pack type epoxy resin composition was adjusted in the same manner as in Example 4 except that the calcium carbonate treated with (D) resin acid in Example 4 was changed to calcium carbonate not subjected to treatment. Table 2 shows the results of measuring and evaluating the inflow distance.

<Comparative example 4>
The one-component epoxy resin composition was adjusted to 45 degrees in the same manner as in Example 3 except that the amount of the calcium carbonate treated with (E) fatty acid in Example 3 was changed from 10 parts by weight to 30 parts by weight. Table 2 shows the results of measuring and evaluating the fluidity and the flow-in distance.

Claims (4)

A one-component liquid epoxy resin composition for hermetically sealing or insulatingly sealing small electronic components or electrical components,
(A) epoxy resin that is liquid at room temperature ,
(B) Dicyandiamide ,
(C) a latent curing agent other than dicyandiamide ,
(D) calcium carbonate having a resin acid treatment on the surface ,
(E) Calcium carbonate whose surface has been subjected to fatty acid treatment ( A) 0.5 to 20 parts by weight with respect to 100 parts by weight of an epoxy resin that is liquid at room temperature ,
One-liquid epoxy resin composition characterized by containing a. 2. The one-component liquid epoxy resin composition according to claim 1, wherein 1 to 35 parts by weight of (D) calcium carbonate whose surface has been subjected to resin acid treatment is contained per 100 parts by weight of the epoxy resin. object. 3. The latent curing agent other than (C) dicyandiamide is at least one selected from the group consisting of an epoxy resin imidazole adduct compound, an epoxy resin amine adduct compound, and a modified aliphatic polyamine compound. One-component liquid epoxy resin composition. The one-component liquid epoxy resin composition according to any one of claims 1 to 3, wherein the small electronic component or the electric component is a relay.