JPH06211965A - New fine particle containing cure accelerator, epoxy resin composition, and cured product - Google Patents

Abstract

PURPOSE:To provide fine particles containing a cure accelerator which can give a one-pack epoxy resin composition excellent in storage stability and curability. CONSTITUTION:The fine particle contains a cure accelerator obtained by adding a cure accelerator to a cured product obtained by subjecting an epoxy resin having at least two epoxy groups in the molecule, a reactive diluent having at least one epoxy group in the molecule and a curing agent to a three- dimensional network formation reaction. The epoxy resin composition contains these particles. The cured product is obtained by curing this composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a curing accelerator-containing fine particle in which a curing accelerator is contained in a cured product of an epoxy resin, and a curable composition containing the same, which is excellent in curability and storage stability at room temperature and has a long pot life. The present invention relates to a liquid epoxy resin composition and a cured product thereof.

[0002]

2. Description of the Related Art Epoxy resins have well-balanced physical properties such as excellent reactivity, excellent adhesion of cured products, small curing shrinkage, excellent mechanical properties, chemical resistance and electrical properties. It is used in a wide range of fields such as coating of automobiles and cans, electrical fields such as encapsulants and laminated plates, civil engineering, and adhesive fields.

Epoxy resin compositions that are generally used at present are manufactured by measuring and mixing the required amounts of each component immediately before use, and it takes a lot of time to mix, there is a possibility of measurement error, and mixing of The operation is complicated, such as variations in performance due to imperfections and changes in workability due to increase in viscosity over time.

Several one-pack type epoxy resin compositions have been reported for the purpose of overcoming these problems. For example, in Japanese Unexamined Patent Publication No. 1-2242616, the film thickness of a capsule is obtained by using a microencapsulated curing accelerator. Although the release is controlled by the one-part epoxy resin composition, it is necessary to adjust the film thickness so as not to impair the low-temperature curability of the curing accelerator, which makes it weak against mechanical external force. It cannot be used when a mixed viscosity preparation is required for the preparation of. on the other hand,
If the film thickness is increased and the film strength is increased, the low temperature curability is impaired.

[0005]

At present, it is desired to develop a one-pack type epoxy resin composition which is excellent in both curability at the time of curing and storage stability at room temperature and which can satisfy the physical properties of the cured product. It is rare.

[0006]

Therefore, the present inventors have made various studies and overcome the problems of the one-pack type epoxy resin composition in the prior art, and the one-pack epoxy which was difficult in the prior art. It was found that both excellent curability in the resin composition and excellent storage stability at room temperature can be achieved,
The present invention has been completed.

That is, the present invention includes 1) (a) an epoxy resin having two or more epoxy groups in one molecule, (b) a reactive diluent having one or more epoxy groups in one molecule, and (c) curing. Curing accelerator-containing fine particles in which a curing accelerator is included in a cured product obtained from the agent, 2) an epoxy resin composition containing the epoxy resin and the curing accelerator-containing fine particles described in 1) above, 3) in 2) above. A cured product of the described epoxy resin composition,
Regarding

In the curing accelerator-containing fine particles of the present invention, by incorporating the curing accelerator into a specific cured product (three-dimensional network), elution of the curing accelerator contained at room temperature is prevented, and the curing accelerator is kept at an appropriate temperature. By heating above,
The included curing accelerators are first eluted and catalyze. Therefore, the epoxy resin composition of the present invention,
It has excellent storage stability at room temperature, and does not cure during mixing and kneading when preparing the epoxy resin composition of the present invention, and has excellent work stability. Furthermore, during curing (molding) of the epoxy resin composition of the present invention, the included curing accelerator elutes and acts as a curing catalyst, and the curing reaction proceeds promptly. That is, it is also excellent in curability during curing.

A cured product having satisfactory physical properties can be obtained by curing the epoxy resin composition of the present invention. The cured product containing the curing accelerator in the curing accelerator-containing fine particles of the present invention is a cured product of an epoxy resin,
It is the same type of resin as the cured product of the epoxy resin composition of the present invention. Therefore, in the cured product of the epoxy resin composition of the present invention, since the curing accelerator-containing fine particles are different from each other and are not foreign substances, the compatibility is good and the physical properties after molding are not adversely affected.
Further, since the curing accelerator-containing fine particles of the present invention can be prepared even under a solvent-free condition, there is no concern that the solvent may adversely affect the epoxy resin composition.

The present invention will be described in detail below. Examples of the (a) epoxy resin having two or more epoxy groups in one molecule used for preparing the curing accelerator-containing fine particles include, for example, bisphenol A glycidyl ether, bisphenol F glycidyl ether, resorcin glycidyl ether, and glycerin. Glycidyl ether,
Glycidyl ethers of polyalkylene oxides, glycidyl ethers of brominated bisphenol A and their oligomers, etc. Glycidyl ether type epoxy resins, phenols, orthocresols and / or naphthols and formalins, aliphatic and aromatic aldehydes or Examples thereof include alicyclic epoxy resins such as epoxy compounds of condensation products with ketones, alicyclic diepoxy acetal, alicyclic diepoxy adipate, and alicyclic diepoxy carboxylate.

In addition, diglycidyl phthalate ester,
Glycidyl ester-based epoxy resin such as tetrahydrophthalic acid diglycidyl ester, hexahedrophthalic acid diglycidyl ester, N, N-diglycidylaniline,
Tetraglycidylaminodiphenylmethane, heterocyclic epoxy resin, hydantoin-type epoxy resin, glycidylamine-based epoxy resin such as triglycidyl isocyanurate, urethane-modified epoxy resin, rubber-modified epoxy resin, polysulfide-based epoxy resin, alkyd-modified epoxy resin, etc. A modified epoxy resin is exemplified. These epoxy resins may be used alone or in combination of two or more. Among these, bisphenol glycidyl ether type epoxy resin, phenol novolac type epoxy resin, gresol novolac type epoxy resin, and heterocyclic type epoxy resin are particularly preferable.

(B) The reactive diluent having one or more epoxy groups in one molecule is not particularly limited.
Aliphatic alkyl glycidyl ethers such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether and allyl glycidyl ether, glycidyl methacrylate, alkyl glycidyl esters such as tertiary carboxylic acid glycidyl ester, styrene oxide, phenyl glycidyl ether, cresyl glycidyl ether, p- s
-Aromatic alkyl glycidyl ethers such as butyl phenyl glycidyl ether and nonyl phenyl glycidyl ether. These may be used alone,
Moreover, you may use together 2 or more types.

(B) Among the reactive diluents having one or more epoxy groups in one molecule, particularly preferred are the compounds having only one epoxy group in one molecule. (B) When a compound having only one epoxy group in one molecule is used as the reactive diluent, these are three-dimensionally reticulated using the components (a), (b) and (c). It becomes easy to control the crosslink density of the obtained cured product to an appropriate value, and it becomes easy to prepare the curing accelerator-containing fine particles having desired properties. That is, by appropriately selecting the type and blending ratio of the component (b), it is possible to easily obtain the curing accelerator-containing fine particles capable of eluting the curing accelerator at a desired temperature.

As the curing agent (c), an ordinary curing agent which can react with an epoxy resin (a) to obtain a three-dimensional network product (cured product) can be used. For example, diethylenetriamine, triethylenetriamine, tetraethylenepentamine, Diethylaminopropylamine, pentaethylenehexamine, menthenediamine, isophoronediamine, N-aminoethylpiperazine, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxyspiro (5.
5) Undecane adduct, bis (4-amino-3-methyl-cyclohexyl) methane, bis (4-aminocyclohexyl) methane, m-xylenediamine, diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, dicyandiamide, adipic dihydrazide Polyamine curing agents such as polyamide polyamine, modified products thereof, eutectic mixtures, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride,
Methyl tetrahydro phthalic anhydride, methyl hexahydro phthalic anhydride, methyl nadic acid anhydride, dodecyl succinic anhydride, chlorendic acid anhydride, pyromellitic dianhydride, benzophenone tetracarboxylic acid anhydride, ethylene glycol bis (anhydro trimate) , Acid anhydride-based curing agents such as methylcyclohexene tetracarboxylic acid anhydride, trimellitic anhydride, polyazelaic acid anhydride,
Polyphenol-based curing agents such as trisphenol, phenol novolac and cresol novolac, polymercaptan-based curing agents such as polymercaptan and polysulfide, etc. can all be used. Preferred are ethylenediamine, diethylenetriamine, hexamethylenediamine and the like. These compounds may be used alone or in combination of two or more kinds.

0.1 to 80% by weight of (b) a reactive diluent having one or more epoxy groups in one molecule is used for (a) an epoxy resin having two or more epoxy groups in one molecule. Is preferable, and it is particularly preferable to use 5 to 40% by weight. The (c) curing agent is preferably used in an amount of 0.1 to 20 equivalents, and particularly preferably 1 to 5 equivalents, relative to 1 equivalent of the total of the components (a) and (b).

Various types of curing accelerators can be used and are not particularly limited. For example, tetramethylguanidine,
Triethanolamine, triethylenediamine, pyridine, picoline, 1,8-diazabicyclo (5,4,0)
Tertiary amines such as -7-undecene, benzylmethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (diaminomethyl) phenol, 2
-Methylimidazole, 2-ethyl-4-methyl-imidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-
2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-
Undecyl imidazole, 2,4-diamino-6- (2
-Methylimidazolyl) -ethyl-S-triazine,
2,4-Diamino-6- (2-ethyl-4-methylimidazolyl) -ethyl-S-triazine, 2,4-diamino-6- (2-undecylimidazolyl) -ethyl-S
-Imidazole compounds such as triazine and salts thereof, tributylphosphine, trioctylphosphine,
Tricyclohexylphosphine, triphenylphosphine, tribenzylphosphine, tritolylphosphine,
Organic phosphine compounds such as p-styrylphosphine, tris (2,6-dimethoxyphenyl) phosphine, tri-4-methylphenylphosphine, tri-4-methoxyphenylphosphine, tri-2-cyanoethylphosphine, bis (diphenylphosphino) methane Examples include phosphinoalkane compounds such as 1,2-bis (diphenylphosphino) ethane and 1,4- (diphenylphosphino) butane, triphenylphosphine-triphenylborane, and tetraphenylphosphonium tetraphenylborate. . Particularly preferred are 1-benzyl-2-methylimidazole, 1,8-diazabicyclo (5,4,0) -7-undecene, 2-methylimidazole, 2-ethyl-4-methylimidazole, dimethylbenzylamine and the like. Is mentioned.

The amount of the curing accelerator contained in the fine particles containing the curing accelerator is not particularly limited, but is usually 1 to 80% by weight, preferably 5 to 30% by weight.

The curing accelerator-containing fine particles can be prepared according to a known method, for example, an interfacial precipitation method, an interfacial polymerization method, a liquid hardening film method, an emulsion polymerization method, a suspension polymerization method and the like. An interfacial polymerization method can be mentioned as a preferable preparation method.

A specific example of a method for preparing fine particles containing a curing accelerator will be shown. A hardening phase, (a) epoxy resin, (b) reactive diluent are mixed in advance to prepare a lipophilic phase, which is mixed with a dispersing (stabilizing) agent, if necessary, an electrolyte, an inorganic fine powder, etc. in an aqueous phase. Disperse into. Here, the stirring speed and the addition amount of the dispersing (stabilizing) agent are adjusted so that the average particle size of the lipophilic phase is 0.001 to 100.
μm, preferably 0.01 to 50 μm, more preferably 0.05 to 20 μm. A curing agent is added to this two-phase dispersion system and polymerized. The polymerization temperature is 0 to 100
C is preferable, and the polymerization time is preferably 3 to 24 hours. By separating fine particles from the obtained reaction mixture, fine particles containing a curing accelerator are obtained.

Examples of the dispersing (stabilizing) agent used in the aqueous phase include polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene nonylphenol ether, sorbitan monolaurate, sorbitan tristearate, polyoxyethylene sorbitan monoether. Nonionic surfactants such as laurate and polyoxysorbitan monooleate, anionic surfactants such as sodium lauryl sulfate and sodium dodecylbenzene sulfonate, cationic such as lauryltrimethylammonium chloride and stearyltrimethylammonium chloride Surfactant, polyvinyl alcohol,
Examples thereof include water-soluble polymer compounds such as sodium polyacrylate, polyvinylpyrrolidone and carboxymethyl cellulose, and natural polymers such as starch and gelatin. Two or more kinds of these dispersing (stabilizing) agents may be used in combination.

For example, the curing accelerator-containing fine particles of the present invention are obtained as described above, but the components (a), (b) and (c) are reacted (cured) to give a three-dimensional network (cured). Object) is formed and the curing accelerator is present in a state of being included in this three-dimensional network. The particle size of the curing accelerator-containing fine particles of the present invention is usually 0.1 to 500 μm, preferably 0.5 to 50 μm, and particularly preferably 1 to 20 μm.
m.

Next, the epoxy resin composition of the present invention will be described. The epoxy resin used as a component of the epoxy resin composition is not particularly limited, and any polyfunctional epoxy resin can be used. For example, various epoxy resins and the like shown as examples of the above-mentioned (a) epoxy resin having two or more epoxy groups in one molecule can be mentioned.

The epoxy resin composition of the present invention may contain a curing agent. The curing agent is not particularly limited, and examples thereof include various curing agents shown as examples of the above-mentioned (c) curing agent. In the epoxy resin composition of the present invention, the curing agent is an optional component and need not always be used. When a curing agent is included, the amount thereof used is preferably 0.01 to 2 equivalents, particularly preferably 0.3 to 1.5 equivalents, relative to 1 equivalent of the epoxy resin.

The curing accelerator-containing fine particles contain the curing accelerator in an amount of 0.05 to 5 relative to the epoxy resin.
It is preferable to use it in an amount to achieve the weight%, especially 0.07 to 3
It is preferably used in an amount that results in weight percent.

The epoxy resin composition of the present invention may further contain an inorganic filler, a flame retardant, a treating agent, a pigment,
Release agents, defoamers, leveling agents, coupling agents, and other additives can be included. The epoxy resin composition of the present invention can be obtained by uniformly mixing the components.

The epoxy resin composition of the present invention can be easily made into a cured product of the epoxy resin composition by the same method as conventionally known. For example, if necessary, the epoxy resin composition of the present invention is uniformly mixed using a kneader, an extruder, a roll, etc., and then melted if necessary, and molded using a casting or transfer molding machine, etc., A cured product can be obtained by heating at 80 to 220 ° C. for 0.5 to 10 hours. Further, the epoxy resin composition of the present invention was obtained by dissolving it in a solvent, impregnating it into a substrate such as glass fiber, glass cloth, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, or paper and then heating and drying it. The prepreg may be hot-press molded to obtain a cured product. It is also possible to prepare a laminated plate by general varnish preparation, impregnation, drying, prepreg formation, lamination and curing. The epoxy resin composition of the present invention is excellent in storage stability at room temperature as a single liquid, and is hardly affected by the cured product in the curing accelerator-containing fine particles on the thermosetting property and the physical properties of the cured product. It can be used in each field.

[0027]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 Preparation of curing accelerator-containing fine particles (MP-1) 2 g of polyoxyethylene nonylphenyl ether and 0.5 g of gelatin were completely dissolved in 100 g of water. Epicoat 828 (bisphenol A type epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd.) 20 prepared separately there
g, glycidyl methacrylate 5 g, 1-benzyl-2
A mixture of 6.25 g of -methyl-imidazole was added, stirred and dispersed. While keeping the temperature inside the container at 60 ° C, 5
10 g of 0% hexamethylenediamine aqueous solution was added dropwise.
After dropping, reacting at 80 ° C. for 2 hours, filtering, washing,
20 g of white fine particles (average particle size 13 μm) were obtained.

Example 2 Preparation of curing accelerator-containing fine particles (MP-2) 2 g of polyoxyethylene nonylphenyl ether and 0.5 g of polyvinyl alcohol were completely dissolved in 100 g of water. 22.5 g of Epicoat 828 (bisphenol A type epoxy resin, manufactured by Yuka Shell Epoxy Co., Ltd.) separately prepared, glycidyl methacrylate 2.
A mixture of 5 g and 12.5 g of 1-benzyl-2-methyl-imidazole (manufactured by Shikoku Kasei) was added, and the mixture was stirred and dispersed. While maintaining the temperature inside the container at 60 ° C., 10 g of a 50% ethylenediamine aqueous solution was added dropwise. 80 after dropping
After reacting at 2 ° C. for 2 hours, the mixture was filtered and washed to obtain 22 g of white fine particles (average particle size 10 μm).

Examples 3 to 7 Preparation of Fine Particles Including Curing Accelerator In the preparation of Example 2, 1-benzyl-2-methyl-
Instead of imidazole, the curing accelerators contained in Table 1 were used, and the other particles were similarly prepared.

[0031]

[Table 1] Table 1 Curing accelerator-containing fine particles Example Curing accelerator Hue average particle size Yield 3 A MP-3 White 12 μm 20 g 4 B MP-4 White 11 μm 20 g 5 C MP-5 White 8 μm 24 g 6 D MP-6 White 10 μm 18 g 7 E MP-7 White 13 μm 21 g

A 2-Ethyl-4-methyl-imidazole (manufactured by Shikoku Kasei) B 2-phenyl-imidazole (manufactured by Shikoku Kasei) C 2-undecyl-imidazole (manufactured by Shikoku Kasei)
D) 2-Methyl-4-cyanoethyl-imidazole (manufactured by Shikoku Kasei) E Triphenylphosphine (Wako Pure Chemical Industries, Ltd.)
Made)

Examples 8 to 12 Preparation of curing accelerator-containing fine particles The epoxy resin (a) used in the preparation method of Example 2 was used.
And / or the reactive diluent (b) was replaced with that shown in Table 2, and the other conditions were the same to prepare fine particles.

[Table 2] Table 2 Fine particles containing a curing accelerator Example (a) (b) Hue Average particle size Yield 8 G IMP-8 White 7 μm 21 g 9 H IMP-9 White 8 μm 20 g 10 F J MP-10 White 13 μm 18 g 11 F K MP-11 white 11 μm 24 g 12 FL MP-12 white 18 μm 21 g

F Epicoat 828 (bisphenol A
Diglycidyl ether), Yuka Shell Epoxy Co., Ltd.
G RE-304S (bisphenol F diglycidyl ether, manufactured by Nippon Kayaku Co., Ltd.) HRGE (resorcin diglycidyl ether, manufactured by Nippon Kayaku Co., Ltd.) I GMA (glycidyl methacrylate, Wako Pure Chemical Industries, Ltd.) J AGE (allyl glycidyl ether, manufactured by Wako Pure Chemical Industries, Ltd.) K TGE-H (P-S-butylphenyl glycidyl ether, manufactured by Nippon Kayaku Co., Ltd.) L Cardura-E (tertiary carboxylic acid glycidyl) Ester, Yuka Shell Epoxy Co., Ltd.

Example 13 Quantification of curing accelerator in fine particles The fine particles obtained in Examples 1 to 12 (MP-
1)-(MP-12) 100mg, put there 50m
l of acetone was added and stirred overnight. The amount of the curing accelerator in the obtained acetone solution was quantified to determine the amount of the curing accelerator in the fine particles. The internal standard method was used for the quantification method. The results were as follows.

1-benzyl-2-methyl-imidazole content MP-1 8.2% MP-2 14.0% MP-8 12.5% MP-9 13.0% MP-10 11.5% MP -11 11.8% MP-12 13.0%

2-Ethyl-4-methyl-imidazole content rate MP-3 8.3% 2-Phenyl-imidazole content rate MP-4 12.1% 2-Undecyl-imidazole content rate MP-5 14.5% 2 -Methyl-4-cyanoethyl-imidazole content MP-6 13.1% Triphenylphosphine content MP-7 5.7%

Example A1 Formulation of Epoxy Resin Composition Using Fine Particles Including Curing Accelerator Epicoat 828 (bisphenol A type epoxy resin,
Yuka Shell Epoxy Co., Ltd.) 10 g, RIKACID MT
-500 (methyltetrahydrophthalic anhydride, manufactured by Shin Nippon Rika Co., Ltd.) 9.1 g, fine particles (MP-1) 1.22 g
Were mixed to obtain a one-pack type epoxy resin composition EP-1.

Examples A2 to A12 Formulation of Epoxy Resin Composition Using Curing Accelerator-Containing Microparticles Table 3 was used instead of the microparticles (MP-1) in Example A1.
One-pack type epoxy resin compositions EP-2 to EP-12 were obtained in the same manner by using the amounts of the fine particles shown in Table 3 in the amounts shown in Table 3.

[0040]

[Table 3] Table 3 Examples Fine particles Amount used One-pack type epoxy resin composition A2 MP-2 0.74 g EP-2 A3 MP-3 1.20 g EP-3 A4 MP-4 0.83 g EP-4 A5 MP -5 0.69 g EP-5 A6 MP-6 0.76 g EP-6 A7 MP-7 1.75 g EP-7 A8 MP-8 0.80 g EP-8 A9 MP-9 0.77 g EP-9 A10 MP -10 0.87 g EP-10 A11 MP-11 0.85 g EP-11 A12 MP-12 0.77 g EP-12

Comparative Example A1 Formulation of Epoxy Resin Composition Used without Incorporating Curing Accelerator into Fine Particles Epicoat 828 (bisphenol A type epoxy resin,
Yuka Shell Epoxy Co., Ltd.) 10 g, RIKACID MT
-500 (methyltetrahydrophthalic anhydride, manufactured by Shin Nippon Rika Co., Ltd.) 9.1 g and 1-benzyl-2-methyl-imidazole (manufactured by Shikoku Kasei Co., Ltd.) 0.1 g were mixed,
Epoxy resin composition H-1 was obtained.

Comparative Example A2 Formulation of Epoxy Resin Composition Used without Incorporating Curing Accelerator into Fine Particles In Comparative Example A1, instead of 1-benzyl-2-methyl-imidazole, a curing accelerator shown in Table 4 was used. Epoxy resin composition H-2
~ H-6 was obtained.

[0043]

Table 4 H-2 2-Ethyl-4-methyl-imidazole (manufactured by Shikoku Kasei) H-3 2-phenyl-imidazole (manufactured by Shikoku Kasei) H-4 2-undecyl-imidazole (Manufactured by Shikoku Kasei) H-5 2-methyl-4-cyanoethyl-imidazole (manufactured by Shikoku Kasei) H-6 triphenylphosphine (manufactured by Wako Pure Chemical Industries, Ltd.)

Example B1 Storage stability test using gel timer Epoxy resin compositions EP-1, EP-2, EP-8 to E
The gelation time of P-12 and H-1 was measured by Gel Time Tester No. 153 (manufactured by Yasuda Seiki Co., Ltd.), 70 ° C, 1
The measurement was carried out at each temperature of 00 ° C. and 120 ° C. and comparison was made. H-1
The relative value of each epoxy resin composition when the gelation time at each temperature was set to 1 was obtained, and this was used as an index of storage stability as a curing delay rate. The results are shown in Table 5.

[0045]

[Table 5] Table 5 Curing delay rate One-pack type epoxy resin composition 70 ° C 100 ° C 120 ° C H-1 1.0 (13117 seconds) 1.0 (1598 seconds) 1.0 (472 seconds) EP-1 44.30 2.41 2.05 EP-2 15.66 1.37 1.14 EP-8 23.42 1.42 0.98 EP-9 16.31 1.25 1.12 EP-10 15.54 2.12 1.80 EP-11 43.11 3.21 1.63 EP-12 46.30 1.25 1.10

Example B2 Storage stability test using gel timer One-pack type epoxy resin composition E was prepared in the same manner as in Example B1.
The gelling times of P-3 to EP-7 were measured, and the gelling times of H-2 to H-6 were set to 1 for the epoxy resin compositions prepared without forming the corresponding curing accelerator into fine particles. The relative value of each of EP-3 to EP-7 at that time was set as a curing delay rate and used as an index of storage stability. The results are shown in Table 6.

[0047]

Table 6 Table 6 Curing delay rate 70 ° C 100 ° C 120 ° C EP-3 8.67 1.21 1.21 EP-4 13.46 2.05 1.11 EP-5 20.10 1.37 1. 10 EP-6 11.31 1.81 1.61 EP-7 14.31 3.47 2.04

Example C1 Formulation of Epoxy Resin Composition Using Fine Particles Including Curing Accelerator Epicoat 828 (bisphenol A type epoxy resin,
Yuka Shell Epoxy Co., Ltd. 50 g, fine particles (MP-
1) Mixing with 6.1 g, one-pack type epoxy resin composition E
P-13 was obtained.

Examples C2 to C12 In Example C1, instead of the fine particles (MP-1), Table 7 was used.
The one-part epoxy resin compositions EP-14 to EP-24 were obtained in the same manner by using the amounts of the fine particles shown in 1 above in the amounts shown in Table 7.

[0050]

[Table 7] Table 7 Examples Fine particles Amount used One-pack type epoxy resin composition C2 MP-2 3.6 g EP-14 C3 MP-3 6.0 g EP-15 C4 MP-4 4.1 g EP-16 C5 MP -5 3.5 g EP-17 C6 MP-6 3.8 g EP-18 C7 MP-7 8.8 g EP-19 C8 MP-8 4.0 g EP-20 C9 MP-9 3.8 g EP-21 C10 MP -10 4.3g EP-22 C11 MP-11 4.2g EP-23 C12 MP-12 2.8g EP-24

Comparative Example C1 Formulation of Epoxy Resin Composition Used without Inclusion of Curing Accelerator in Fine Particles Epicoat 828 (bisphenol A type epoxy resin,
Yuka Shell Epoxy Co., Ltd.) 50 g, 1-benzyl-
2-methyl-imidazole (manufactured by Shikoku Kasei Co., Ltd.) 0.5
g was mixed to obtain an epoxy resin composition H-7.

Comparative Example C2 Formulation of Epoxy Resin Composition Used without Incorporating Curing Accelerator in Fine Particles In Comparative Example C1, 1-benzyl-2-methylimidazole was replaced with the one shown in Table 8 and the others were the same. Then, epoxy resin compositions H-8 to H-12 were obtained.

[0052]

Table 8 H-8 2-Ethyl-4-methyl-imidazole (manufactured by Shikoku Kasei) H-9 2-phenyl-imidazole (manufactured by Shikoku Kasei) H-10 2-undecyl-imidazole (Manufactured by Shikoku Kasei Co., Ltd.) H-11 2-methyl-4-cyanoethyl-imidazole (manufactured by Shikoku Kasei Co., Ltd.) H-12 triphenylphosphine (manufactured by Wako Pure Chemical Industries, Ltd.)

Example D1 Long-term storage stability test utilizing viscosity change Epoxy resin compositions EP-13 to EP-24 and H-7
The long-term storage stability of ~ H-12 at 50 ° C was measured using a rotary viscometer Vismetron VS-A1 type (manufactured by Seiki Kogyo Laboratories) and compared. The results are shown in Table 9.

[0054]

Table 9 Epoxy resin composition Initial viscosity (poise) After 3 days (poise) H-7 150 cure (after 1 day) H-8 150 cure (after 1 day) H-9 150 cure H-10 150 cure H- 11 150 Curing H-12 150 Curing EP-13 300 300 EP-14 300 300 EP-15 300 300 EP-16 300 300 EP-17 300 300 EP-18 300 300 EP-19 300 300 EP-20 300 300 EP- 21 300 300 EP-22 300 300 EP-23 300 300 EP-24 300 300

Example E1 Formulation of Epoxy Resin Composition Using Fine Particles Including Curing Accelerator Epicoat 828 (bisphenol A type epoxy resin,
Yuka Shell Epoxy Co., Ltd.) 100 g, RIKACID M
91 g of T-500 (methyl tetrahydrophthalic anhydride, manufactured by Shin Nippon Rika Co., Ltd.), fine particles (MP-1) 12.20
Aerosil R812 (Aerosil Co., Ltd.) 11.
46 g are mixed and mixed with a three roll for 30 minutes,
A one-pack type epoxy resin composition EP-25 was obtained.

Example E2 Compounding of Epoxy Resin Composition Using Fine Particles Including Curing Accelerator In Example E1, 7.14 g of fine particles (MP-2) was used instead of the fine particles (MP-1), and A one-pack type epoxy resin composition EP-26 was obtained.

Comparative Example E1 Formulation of Epoxy Resin Composition Used without Inclusion of Curing Accelerator in Fine Particles Epicoat 828 (bisphenol A type epoxy resin,
Yuka Shell Epoxy Co., Ltd.) 100 g, RIKACID M
91 g of T-500 (methyl tetrahydrophthalic anhydride, manufactured by Shin Nippon Rika Co., Ltd.), 1-benzyl-2-methyl-imidazole (manufactured by Shikoku Kasei Co., Ltd.), Aerosil R8
12,11.46g was mixed and three rolls were used.
The mixture was mixed for a minute to obtain an epoxy resin composition H-13.

Example F1 Preparation of Epoxy Resin Cured Product Epoxy resin compositions EP-25, EP-26 and H-13 compounded in Examples E1 and E2 and Comparative Example E1 were each placed in a predetermined mold defined by JIS K6911. It was poured and cured in an oven at 120 ° C. for 1 hour and 150 ° C. for 4 hours to obtain cured products EPK-25, EPK-26 and HK-13, respectively.

Evaluation of Physical Properties of Cured Product Obtained Epoxy Resin Cured Product EPK-25, EPK-2
6, the Tg (glass transition temperature) of HK-13 was measured by a thermomechanical tester (TMA-7000, Vacuum Riko Co., Ltd.), and all were 135 ° C.

[0060]

By incorporating the curing accelerator-containing fine particles of the present invention into an epoxy resin composition, the following excellent effects can be obtained. 1) It is possible to maintain storage stability for a long period of time without impairing the immediate curing property at high temperature. 2) Since a one-pack type epoxy resin composition can be easily prepared, workability during use is improved, variation between lots is small, and high product reliability is obtained. 3) A good cured product can be obtained by heating above a predetermined temperature without applying a mechanical external force. 4) Since it has excellent storage stability, it has a long pot life and has no change in performance even at room temperature and can be stored for a long period of time. 5) The curing accelerator-containing fine particles of the present invention do not have a physical adverse effect on the cured epoxy resin. Taking advantage of such effects, for example, in the field of adhesives in the fields of electricity and automobiles, or in the field of sealing materials, in the field of coatings such as powder coatings and conductive coatings, electrical insulating materials, and laminated structures. It can be used for.

Claims (3)

[Claims] 1. A curing obtained from (a) an epoxy resin having two or more epoxy groups in one molecule, (b) a reactive diluent having one or more epoxy groups in one molecule, and (c) a curing agent. A curing accelerator-containing fine particle in which a curing accelerator is included in the product. 2. An epoxy resin composition containing an epoxy resin and the curing accelerator-containing fine particles according to claim 1. 3. A cured product of the epoxy resin composition according to claim 2.