JP5792593B2 - Epoxy resin composition for dip coating - Google Patents

Description

  The present invention relates to an epoxy resin composition for dip coating, and particularly relates to an epoxy resin composition for dip coating that has improved viscosity characteristics and good workability and shell life.

  Epoxy resin compositions having thixotropic properties (thixotropic properties; hereinafter also referred to as thixotropic properties) are widely used as dip coating resins for small electronic components such as capacitors, resistors, and hybrid ICs. In such thixotropic epoxy resin composition, it is required that the thixotropic modification of the epoxy resin composition after the addition of the curing agent is small, the moisture resistance of the cured product is good. If the time-lapse deterioration of the thixotropic property of the epoxy resin composition after mixing the curing agent is large, the coating film thickness is not constant, and sagging occurs in an early time, and a coating film having a uniform thickness cannot be obtained. Moreover, when the moisture resistance of a coating film is bad, the electrical property of a coating film will deteriorate and it will become impossible to protect an electronic component safely.

  By the way, an epoxy resin composition having thixotropic properties can be obtained by adding a filler such as colloidal silica or bentonite to the epoxy resin, but the addition of such a filler alone is sufficient. In many cases, denaturation cannot be obtained.

  In Patent Document 1, in order to improve thixotropy of the epoxy resin composition, an amide compound such as formamide and dimethylformamide and a hydroxyl group-containing compound such as methyl carbitol, diethylene glycol, and ethylene glycol are added. An epoxy resin composition with improved thixotropic properties is disclosed. However, this composition has improved thixotropic properties, but has a problem of poor workability due to the addition of a large amount of the hydroxyl group-containing compound.

  On the other hand, in Patent Document 2, in order to improve thixotropy and moisture resistance, a two-component epoxy resin composition comprising a first liquid containing an epoxy resin and a second liquid containing a curing agent is used. A structure in which the ratio of the structural viscosity of the mixture with the two liquids at the initial stage at 25 ° C. and after storage for 6 hours is in a specific range is disclosed. However, in this composition, since the amount of hydrophilic silica added is large, there is a problem that moisture is easily absorbed and the shell life of the composition is poor.

Japanese Patent Laid-Open No. 1-188552 JP-A-5-156127

  The present invention has been made in order to solve the above-described problems of the prior art, and an object thereof is to provide an epoxy resin composition for dip coating that improves viscosity characteristics and has good workability and shell life.

  In order to achieve the above object, the present inventors have intensively studied. As a result, they have found that a resin composition having a specific composition satisfies the above characteristics, and completed the present invention.

  That is, the epoxy resin composition for dip coating of the present invention comprises (A) a liquid bisphenol glycidyl ether type epoxy resin, (B) a glycidylamine type tetrafunctional epoxy resin, (C) a polyfunctional diluent, D) It comprises a first liquid containing silica powder, (E) a liquid aromatic amine curing agent, and (F) a second liquid containing triethanolamine.

  According to the epoxy resin composition for dip coating of the present invention, by improving the viscosity characteristics, an epoxy resin composition for dip coating having good workability and shell life can be obtained, and a stable coating film is formed. be able to.

  Embodiments of the present invention will be described below.

  The epoxy resin composition for dip coating of the present invention comprises (A) a liquid bisphenol glycidyl ether type epoxy resin, (B) a glycidylamine type tetrafunctional epoxy resin, (C) a polyfunctional diluent, and (D) A first liquid containing silica powder, (E) a liquid aromatic amine curing agent, and (F) a second liquid containing triethanolamine.

  First, each component used for the first liquid will be described. The (A) component bisphenol glycidyl ether type epoxy resin used in the first liquid is an epoxy resin obtained by reacting bisphenols such as bisphenol A, bisphenol F, bisphenol AD, hydrogenated bisphenol A and epichlorohydrin, If it is liquid at normal temperature, it will be used without any particular limitation. (A) The epoxy resin of a component may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  The (B) component glycidylamine type tetrafunctional epoxy resin used in the first liquid has four functional groups, and thus has high reactivity and crosslinking density, heat resistance, high strength, high hardness, and chemical resistance. It is an epoxy resin that can give an excellent cured product. Moreover, it discovered newly that the workability | operativity and shell life of a resin composition can be improved by making this epoxy resin a thing of a nitrogen modification. Examples of the glycidylamine-type tetrafunctional epoxy resin include tetraglycidyldiaminodiphenylmethane type epoxy resin, tetraglycidyldiaminodiphenylmethane type epoxy resin, and more specifically, JER604 (trade name; Tetra; manufactured by Mitsubishi Chemical Corporation). Glycidyl diaminodiphenylmethane type epoxy resin) and the like.

  In the present invention, two types of epoxy resins (A) and (B) are essential curing components, and their blending ratio is 90:10 to 10:90 on a mass basis. It is preferable that it is 70: 30-60: 40. When the ratio of the component (A) increases, the ratio of the component (B) decreases too much, the viscosity is low and the workability deteriorates, the ratio of the component (A) decreases and the ratio of the component (B) increases too much. Viscosity increases and workability deteriorates.

  The polyfunctional diluent of the component (C) used in the first liquid is a reactive diluent having a functional group of 2 or more, preferably 3 or more, and usually reduces the viscosity of the composition for dip coating, Unlike the reactive diluent for reducing the viscosity, the viscosity reducing effect is low, but the viscosity is improved and workability is improved while reducing or maintaining the thixotropy of the resin composition.

  Examples of the polyfunctional diluent (C) include neopentyl glycol diglycidyl ether, 1,6-hexanediol, hexahydrophthalic acid diglycidyl ester, propylene glycol diglycidyl ether, and diglycerin polyglycidyl ether. In particular, a trifunctional diluent is preferable, and a product example is trimethylolpropane polyglycidyl ether (manufactured by Sakamoto Pharmaceutical Co., Ltd., trade name: SR-TMP).

  The compounding quantity has the preferable range of 5-30 mass parts with respect to 100 mass parts of epoxy resins of the said (A) and (B) component. If the amount is less than 5 parts by mass, the composition of the present invention cannot be adjusted to an appropriate viscosity, and if the amount exceeds 30 parts by mass, the properties of the cured product will be poor.

  The component (D) used in the first liquid is silica powder, which is a component added as a thixotropic agent. Examples of the silica powder used in the present invention include colloidal silica. Examples of the colloidal silica include hydrophilic silica and hydrophobic silica. These may be used alone, but are preferably used in combination in the present invention. When used in combination, the moisture resistance can be improved and the pot life can be improved.

Examples of the hydrophilic silica include hydrophilic fumed silica obtained by flame hydrolysis of silicon tetrachloride. The hydrophilic fumed silica preferably has a hydrophilic silanol group on its surface, a primary particle diameter of 5 to 20 nm, and a specific surface area (BET) of 40 to 400 m ² / g. Examples of such commercially available products of hydrophilic fumed silica include Aerosil # 300 and # 200 (all of which are manufactured by Nippon Aerosil Co., Ltd., trade names).

Hydrophobic silica is fumed silica that has been hydrophobized by chemically treating the above-mentioned hydrophilic fumed silica with silane, siloxane, etc., with a primary particle size of 7 to 25 nm and a specific surface area (BET). ) Is preferably 50 to 500 m ² / g. Examples of such commercially available products of hydrophobic fumed silica include RY200S (trade name, manufactured by Nippon Aerosil Co., Ltd.).

  The primary particle diameter of the hydrophilic silica and hydrophobic silica can be measured by, for example, a dynamic light scattering method.

  Here, the blending amount of (D) silica powder is preferably in the range of 2.0 to 5.0 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resins of the components (A) and (B). If the blending amount is less than 2.0 parts by mass, thixotropy becomes insufficient, and if it exceeds 5.0 parts by mass, the viscosity and thixotropy become excessively high and it becomes difficult to coat with a uniform film thickness. .

  Moreover, in the silica powder blended in such an amount, the blending ratio when hydrophilic silica and hydrophobic silica are used in combination is preferably within a range where the proportion of hydrophobic silica is 10 to 50% by mass of the entire silica, The range which becomes 20-30 mass% is more preferable. If the proportion of the hydrophobic silica is less than 10% by mass, the pot life of the composition cannot be made sufficiently long, and the viscosity after mixing the first and second liquids increases, resulting in a finished coating. May become defective. Moreover, when it exceeds 50 mass%, thixotropy falls and both hydrophilic silica and hydrophobic silica will precipitate easily.

  Next, each component used for the second liquid will be described. The aromatic amine curing agent (E) used for the second liquid is not particularly limited as long as it is liquid at room temperature. Specific examples include eutectic mixtures of metaphenylenediamine and diaminodiphenylmethane, adducts of such eutectic mixtures and epoxy compounds (for example, Ancamine Z (trade name, manufactured by Air Products Co., Ltd.)), diamino Diethyldiphenylmethane (for example, Kayahard (Nippon Kayaku Co., Ltd., trade name), etc.), diaminodiphenylmethane crude (for example, MDA-150 (Mitsui Toatsu Chemical Co., Ltd., trade name)), diethyltoluenediamine (For example, Albemarle Corp., trade name), etc.), condensates of aniline and holymarin (for example, Laccamide WH-619 (Dainippon Ink Chemical Co., Ltd., trade name)) and the like. .

  These aromatic amine curing agents may be used alone or in a combination of two or more. As the aromatic amine-based curing agent of component (E), eutectic mixture of metaphenylenediamine and diaminodiphenylmethane, particularly such eutectic mixture from the viewpoint of reactivity, heat resistance of cured product, moisture resistance, etc. Adducts of benzene and epoxy compounds are preferred.

  The blending amount of the aromatic amine curing agent as the component (E) is preferably in the range of 1 to 40 parts by mass with respect to 100 parts by mass of the total amount of the epoxy resins as the components (A) and (B). The range of parts by mass is more preferable. If the blending amount is less than 1 part by mass, the glass transition temperature may decrease and the heat resistance may decrease. Moreover, when a compounding quantity exceeds 40 mass parts, there exists a possibility that moisture resistance may fall.

  The use of other curing agents for epoxy resins, such as acid anhydrides, imidazoles, dicyandiamides, aliphatic amines, etc. reduces the thixotropic properties of the composition, and the moisture resistance of the cured product. Therefore, it is preferable to use only an aromatic amine curing agent as the curing agent component.

  The triethanolamine or salt thereof as the component (F) used in the second liquid is a component that is blended to enhance thixotropy caused by (D) silica powder, and the blending amount thereof is (A) and (B) The range of 0.1-2.0 mass parts is preferable with respect to 100 mass parts of total amounts of the epoxy resin of a component, and the range of 1.0-1.5 mass parts is more preferable. If the blending amount is less than 0.1 parts by mass, the thixotropic enhancing effect is small, and if the blending amount exceeds 2.0 parts by mass, the curing reaction between the epoxy resin and the aromatic amine curing agent is promoted, and the composition There is a risk of shortening the pot life.

  Examples of the salt of triethanolamine include lower carboxylate (such as acetate and propionate) and inorganic acid salt. Triethanolamine and its salt may be used in combination.

  In the epoxy resin composition for dip coating of the present invention, in addition to the components described above, powder fillers other than the above silica powder, flame retardants, and colorants, as long as the effects of the present invention are not impaired Other additives can be blended. Examples of powder fillers include crystalline silica, fused silica, calcium carbonate, talc, mica, alumina, aluminum hydroxide, white carbon, zirconia, titanium white, bengara, silicon carbide, boron nitride, aluminum nitride, silicon nitride, magnesia. And magnesium silicate. Examples of the flame retardant include powdery organic halogen compounds, red phosphorus, phosphate esters, antimony trioxide and the like. Examples of the colorant include various pigments and dyes such as carbon black and cobalt blue. In addition, you may mix | blend these components with any one of a 1st liquid and a 2nd liquid, or may mix | blend with both. From the viewpoint of preventing the precipitation of the filler, it is preferable to blend in the first liquid.

  As described above, the epoxy resin composition for dip coating of the present invention comprises (A) a liquid bisphenol glycidyl ether type epoxy resin, (B) a glycidyl type tetrafunctional epoxy resin, and (C) a polyfunctional diluent. , (D) a first liquid containing silica powder, (E) a liquid aromatic amine curing agent, and (F) a second liquid containing triethanolamine or a salt thereof. Both liquids are used in a predetermined ratio.

  The first liquid is prepared by mixing the liquid bisphenol glycidyl ether type epoxy resin (A) and the (B) glycidyl type tetrafunctional epoxy resin in advance, and further adding the silica powder (D) and stirring. After mixing, the polyfunctional diluent of component (C) is added, and the mixture is further stirred and mixed for a short time, for example, about 30 minutes. When adding the above-mentioned optional fillers, flame retardants, colorants and the like, for example, they may be mixed and dispersed by a three-roll roll or the like. The stirring and mixing of the (A) and (B) component epoxy resins and the (D) component silica powder results in an equilibrium viscosity composition in which the viscosity of the first liquid reaches a substantially equilibrium viscosity (equilibrium viscosity). It is preferable to carry out so that it may be obtained. For this purpose, silica powder is added to the epoxy resin, and is usually stirred for 2 hours or longer, preferably 3 to 5 hours. As a stirring and mixing device for obtaining the first liquid, for example, a planetary mixer or the like can be used.

  The adjustment of the second liquid can be easily obtained by adding (F) triethanolamine or a salt thereof to (E) a liquid aromatic amine curing agent and mixing.

  The epoxy resin composition for dip coating according to the present invention mixes a predetermined amount as described above, so that the thixotropy (rotation) at 25 ° C. of the mixture immediately after mixing the first liquid and the second liquid (initial stage). The ratio of the viscosity at 4 rotations to the viscosity at 20 rotations by the viscometer; the structural viscosity ratio) can be kept low. This thixotropy is preferably in the range of 1.4 to 1.9 for dip coating. If the thixotropy is less than 1.4, sagging is likely to occur after coating, and if it exceeds 1.9, thixotropy becomes strong and uniform coating may not be possible. This thixotropy can be appropriately adjusted by the amount of colloidal silica added, the amount of thixotropic agent added, and the like.

  Moreover, the workability at the time of the dip coating of the resin composition can be improved by setting the thixotropic property to 3 dPa · s or more while satisfying the above-mentioned range after the first liquid and the second liquid are mixed. The viscosity is preferably 4 to 10 dPa · s.

  Moreover, the coating film thickness in the case of dip-coating an electronic component with a resin composition is usually 0.2 to 0.4 mm in many cases. However, when the coating is thinner than 0.2 mm, or when the viscosity of the raw resin solution is high and it is difficult to obtain a predetermined film thickness, the reactive diluent is used for the purpose of reducing the viscosity of the resin composition of the present invention. It is good to add. Examples of the reactive diluent used herein include reactive diluents other than the (C) polyfunctional diluent of the present invention, and an epoxy compound having one epoxy group in the molecule and a viscosity at 25 ° C. of 200 cps or less. Is used.

  Examples of such reactive diluents include those conventionally used for viscosity reduction. For example, butyl glycidyl ether, phenyl glycidyl ether, alkylphenol glycidyl ether, allyl glycidyl ether, butanediol glycidyl ether, hexanediol Examples thereof include diglycidyl ether and neopentyl glycol diglycidyl ether.

  The amount of the reactive diluent added is the amount of the reactive diluent for reducing the viscosity added to the polyfunctional diluent of component (A) and component (B) and the polyfunctional diluent of component (C). It is 30 mass% or less with respect to a mixture, Preferably it is 1-30 mass%, More preferably, it is 5-20 mass%. If it exceeds 30% by mass, the cured product properties will deteriorate.

  Next, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to these Examples at all. In the following description, “part” means “part by mass”.

Example 1
Bisphenol A type epoxy resin (trade name: jER828; Epoxy equivalent 188, manufactured by Mitsubishi Chemical Corporation) as bisphenol glycidyl ether type epoxy resin which is liquid at room temperature 70 parts, N, N, N as glycidylamine type tetrafunctional epoxy resin ', N'-tetraglycidyldiaminodiphenylmethane type epoxy resin (Mitsubishi Chemical Co., Ltd., trade name: jER604; epoxy equivalent 120) Trimethylolpropane polyglycidyl as a multifunctional diluent in an epoxy resin mixed with 30 parts 10 parts ether (manufactured by Sakamoto Pharmaceutical Co., Ltd., trade name: SR-TMP), hydrophilic fumed silica as silica powder (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil # 200; primary particle size 1.4 nm, Specific surface area 200 m ² / g) 3 parts and hydrophobic fumed silica ( Nippon Aerosil Co., Ltd., trade name: Aerosil RY200S; primary particle size 15 μm, specific surface area 80 m ² / g) 1 part is added, and after the addition, the mixture is stirred and mixed for 3 hours. Was prepared. For the preparation of the first liquid, a double planetary mixer (model PLM-5) manufactured by Inoue Seisakusho Co., Ltd. was used and stirred at a rotation speed of 84 rpm and a revolution speed of 26 rpm.
Moreover, 10 parts of aromatic amine type hardening | curing agents (1) (The Air Products Co., Ltd. make, brand name: Ancamin Z) as a hardening | curing agent, and aromatic amine type hardening | curing agents (2) (The Air Products KK make, brand names) : Etacure 100) To 10 parts, 1 part of triethanolamine (manufactured by Wako Pure Chemical Industries, Ltd.) as an additive was added in a conventional manner and mixed to prepare a second liquid.
Then, these 1st liquids and 2nd liquids were mixed and the epoxy resin composition was obtained.

(Example 2)
80 parts of bisphenol A type epoxy resin (trade name: jER828; epoxy equivalent 188, manufactured by Mitsubishi Chemical Corporation), N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane type epoxy resin (Mitsubishi Chemical ( Co., Ltd., trade name: jER604; epoxy equivalent 120) except that the blending amount was changed to 20 parts, the first liquid and the second liquid were prepared in the same manner as in Example 1, and these first liquids were further prepared. And the 2nd liquid was mixed and the epoxy resin composition was obtained.

(Example 3)
60 parts of bisphenol A type epoxy resin (Mitsubishi Chemical Corporation, trade name: jER828; epoxy equivalent 188), N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane type epoxy resin (Mitsubishi Chemical ( Co., Ltd., trade name: jER604; epoxy equivalent 120) except that the blending amount was changed to 40 parts, the first and second liquids were prepared in the same manner as in Example 1, and these first liquids were further prepared. And the 2nd liquid was mixed and the epoxy resin composition was obtained.

Example 4
70 parts of bisphenol A type epoxy resin (Mitsubishi Chemical Corporation, trade name: jER828; epoxy equivalent 188), N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane type epoxy resin (Mitsubishi Chemical ( Co., Ltd., trade name: jER604; epoxy equivalent 120) 30 parts, polyfunctional diluent trimethylolpropane polyglycidyl ether (Sakamoto Pharmaceutical Co., Ltd., trade name: SR-TMP) The first liquid and the second liquid were prepared in the same manner as in Example 1 except that the blending amount was changed to 5 parts, and the first liquid and the second liquid were further mixed to obtain an epoxy resin composition. Obtained.

(Example 5)
70 parts of bisphenol A type epoxy resin (Mitsubishi Chemical Corporation, trade name: jER828; epoxy equivalent 188), N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane type epoxy resin (Mitsubishi Chemical ( Co., Ltd., trade name: jER604; epoxy equivalent 120) 30 parts, polyfunctional diluent trimethylolpropane polyglycidyl ether (Sakamoto Pharmaceutical Co., Ltd., trade name: SR-TMP) The first liquid and the second liquid were prepared in the same manner as in Example 1 except that the blending amount was changed to 20 parts, and the first liquid and the second liquid were further mixed to obtain an epoxy resin composition. Obtained.

(Comparative Example 1)
As an epoxy resin, a bisphenol A type epoxy resin (trade name: jER828; epoxy equivalent 188, manufactured by Mitsubishi Chemical Corporation), which is a liquid bisphenol glycidyl ether type epoxy resin at room temperature, is used alone, and its blending amount is 100 parts. Example 1 was used except that 10 parts of monofunctional butyl glycidyl ether (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., trade name: BGE-R) was used as a diluent instead of trimethylolpropane / polyglycidyl ether. A first liquid and a second liquid were prepared, and further, the first liquid and the second liquid were mixed to obtain an epoxy resin composition.

(Comparative Example 2)
N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane type epoxy resin (Mitsubishi Chemical Corporation, trade name: jER604; epoxy equivalent 120) Paraaminophenol type epoxy resin (Mitsubishi Chemical Corporation) instead of 30 parts ), Trade name: jER630; epoxy equivalent 95) Except for using 30 parts, the first and second liquids were prepared in the same manner as in Example 1, and the first and second liquids were further prepared. An epoxy resin composition was obtained by mixing.

(Comparative Example 3)
N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane type epoxy resin (Mitsubishi Chemical Corporation, trade name: jER604; epoxy equivalent 120) Instead of 30 parts, solid bisphenol glycidyl ether type epoxy resin (Mitsubishi Chemical Co., Ltd., trade name: jER1001; epoxy equivalent 400) Except for using 30 parts, a first liquid and a second liquid were prepared in the same manner as in Example 1, and the first and second liquids were further prepared. Two liquids were mixed to obtain an epoxy resin composition.

(Comparative Example 4)
N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane type epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: jER604; epoxy equivalent 120) Instead of 30 parts, tris (4-glycidoxyphenyl) di Glycidyl methane (manufactured by Dow Chemical Co., Ltd., trade name: XD-7347; epoxy equivalent 200) A first liquid and a second liquid were prepared in the same manner as in Example 1 except that 30 parts were used. The liquid and the second liquid were mixed to obtain an epoxy resin composition.

  About the epoxy resin composition obtained by each said Example and each comparative example, various characteristics were evaluated by the method shown below. The results are shown in Table 1 and Table 2 together with the composition.

[Thixotropic]
Using a rotational viscometer (Bismometron VGH viscometer manufactured by Shibaura System Co., Ltd.), the 1st and 2nd liquids were mixed and after 1 minute, the viscosity (η ₂₀ ) at 25 ° C. and 20 rpm Viscosity (η ₄ ) was measured and determined by the following formula to obtain thixotropy (structural viscosity ratio).
Thixotropic = η ₄ / η ₂₀

[viscosity]
Using a rotational viscometer (Bismometron VGH viscometer manufactured by Shibaura System Co., Ltd.), the viscosity after 1 minute of mixing the first and second liquids was measured at 25 ° C.

[Workability]
A glass rod having a diameter of 3 mm was dipped in the epoxy resin composition for 3 seconds, then pulled up, measured for the time when no holes were formed when pulled up, and evaluated according to the following criteria.
○: Within 10 seconds, ×: Over 10 seconds

[Shell Life]
The first liquid and the second liquid were each stored at 60 ° C. for 90 days, and then mixed to form an epoxy resin composition. Then, a φ3 mm glass rod was immersed in the resin composition for 3 seconds. Then, it was pulled up and the appearance was confirmed. At this time, the surface state of the coating was visually observed and evaluated according to the following criteria.
○: Uniform throughout, △: Partially non-uniform, x: Almost non-uniform

[Glass transition point (Tg)]
The glass transition point (Tg) was measured by the TMA method using a thermomechanical analyzer (TA instruments, trade name: Q400).

  As is apparent from Tables 1 and 2, the epoxy resin compositions of the examples of the present invention can reduce or maintain the thixotropy at the beginning of mixing, increase the viscosity, and have good workability during dip coating. In addition, the shell life of the resin composition could be improved. It was also found that the glass transition point (Tg) obtained was high, and that it could be used in a higher temperature environment than before.

Claims (6)

  A first liquid containing (A) a liquid bisphenol glycidyl ether type epoxy resin, (B) a glycidylamine type tetrafunctional epoxy resin, (C) a polyfunctional diluent, and (D) silica powder; An epoxy resin composition for dip coating, comprising: a liquid aromatic amine curing agent; and (F) a second liquid containing triethanolamine or a salt thereof.   The first liquid contains 5 to 30 parts by mass of the component (C) and 2 to 5 parts by mass of the component (D) with respect to 100 parts by mass of the total amount of the components (A) and (B). The epoxy resin composition for dip coating according to claim 1.   The epoxy resin composition for dip coating according to claim 1 or 2, wherein a blending ratio of the component (A) and the component (B) is 90:10 to 10:90 on a mass basis.   The epoxy resin composition for dip coating according to any one of claims 1 to 3, wherein the component (C) is trimethylolpropane polyglycidyl ether.   The epoxy resin composition for dip coating according to any one of claims 1 to 4, wherein the component (D) is a mixture of hydrophilic silica and hydrophobic silica.   The viscosity after mixing of the first liquid and the second liquid is 4 to 10 dPa · s, and the thixotropy is 1.4 to 1.9. 6. Epoxy resin composition for dip coating.