JP3122814B2 - Curing accelerator for epoxy resin and epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a curing accelerator for epoxy resins and an epoxy resin composition.

[0002]

The epoxy resin has a cured product having excellent electrical insulation, moisture resistance, heat resistance, solder resistance, chemical resistance, durability, adhesion, mechanical strength and the like. Therefore, they are widely used as sealing materials, adhesives, paints, and the like, for example, for fixed resistors, electronic components such as semiconductors, and laminated boards. In particular, with the remarkable development of electronic equipment, its use as an encapsulating material for electronic components is increasing in importance.

[0003] Curing of the epoxy resin is carried out by adding a curing agent to the epoxy resin component and, if necessary, heating. Here, examples of the curing agent include aliphatic primary amines, acid anhydrides, imidazoles, dicyandiamide, amine complexes of boron trifluoride, and dihydrazide compounds.

Among these curing agents, when aliphatic primary amines are used, the curing reaction proceeds even at room temperature, so that they must be used immediately after mixing with an epoxy resin.
There is a problem that workability is very poor. That is, the aliphatic primary amines have a disadvantage that the time that can be stored in a temperature range from room temperature to around 40 ° C. (hereinafter referred to as “pot life” or “pot life”) in an mixed state with an epoxy resin is extremely short. have. The curing reaction of imidazoles also proceeds at room temperature, and their pot life is not extremely short, but still not sufficient, as aliphatic primary amines. In addition, cured products obtained using imidazoles have insufficient moisture resistance.

On the other hand, acid anhydrides, dicyandiamide, amine complexes of boron trifluoride, dihydrazide compounds and the like do not undergo a curing reaction at around room temperature, and usually undergo curing only when heated to 100 ° C. or higher. It is a latent curing agent and has the advantage that the pot life is very long. However, acid anhydrides readily react with moisture in the air to form free acids, which reduce the physical properties of the cured product. It costs. When dicyandiamide is used, the cured product of dicyandiamide becomes insufficient in terms of moisture resistance, and is particularly unsuitable for use as a sealing material for electronic parts and the like. The amine complex of boron trifluoride has a drawback that an amine gas is generated at the time of curing and the cured product is discolored. Furthermore, these latent curing agents except for the dihydrazide compound have a disadvantage that part of the latent curing agent remains in the cured product as it is, releasing ions such as hydrogen ions and imparting conductivity to the cured product. is there. When such a cured product is used, for example, as a sealing material for electronic components, it is inevitable that insulation failure occurs and the reliability of electronic / electric devices is significantly reduced.

On the other hand, dihydrazide compounds do not have the drawbacks found in other latent curing agents,
A very high curing temperature of 0 to 180 ° C is required, and the curing time is extremely long, several hours or more, and the energy cost and running cost are significantly increased, which is not industrially preferable. Therefore, in order to solve such a problem, a curing accelerator is usually added together with the dihydrazide compound. Examples of such curing accelerators include tertiary amines such as tri-n-butylamine, benzylmethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, 2-ethylimidazole, 2-ethyl-4- Examples thereof include imidazoles such as methylimidazole and 2-phenylimidazole. However, when tertiary amines are used, a gas having a pungent odor is generated during the curing reaction, and the obtained cured product is liable to cause remarkable heat shrinkage, and a desired shape may not be obtained. Further, the effect of accelerating the curing is not satisfactory. On the other hand, when an imidazole is used in combination with a dihydrazide compound, the imidazole reacts more easily with the epoxy resin component than the dihydrazide compound. The dihydrazide compound of the reaction remains, deteriorating the physical properties of the cured product.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have obtained a novel epoxy resin curing accelerator and a novel epoxy resin composition containing the curing accelerator. We succeeded in obtaining the present invention.

That is, the present invention relates to a curing accelerator for an epoxy resin containing a triazole compound, and an epoxy resin composition containing an epoxy resin, a dihydrazide compound and the curing accelerator for an epoxy resin.

According to the present invention, there is provided a curing accelerator suitable for an epoxy resin composition containing a dihydrazide compound as a curing agent. That is, when the epoxy resin is cured with the dihydrazide compound, the curing time can be significantly shortened by adding the epoxy resin curing accelerator of the present invention. Further, if the curing accelerator of the present invention is used, the obtained cured product may cause heat shrinkage, the dihydrazide compound may remain in the cured product without being reacted, or a gas may be generated during curing. Absent. Further, a cured product of the epoxy resin obtained by using the curing accelerator of the present invention,
It is excellent not only in moisture resistance but also in various other physical properties.

For example, when the curing temperature is around 140 ° C., the curing time may be as short as about 5 to 15 minutes.
When the curing temperature is around 120 ° C., the curing time is 20 minutes.
A short time of about 30 minutes is sufficient. As described above, the original curing time (several hours or more) of the dihydrazide compound can be significantly reduced.

Further, when the curing accelerator for epoxy resin of the present invention and the monohydrazide compound are used in combination as the curing accelerator, a further shortening of the curing time can be achieved by their synergistic effect. For example, curing temperature 14
The curing time around 0 ° C. is 8 minutes or less, and the curing time around 120 ° C. is 10 minutes or less.

The epoxy resin composition of the present invention can be used for the same applications as conventional epoxy resin compositions. Specific applications include, for example, sealing materials for electronic components such as capacitors, resistors, flyback transformers, magnetic heads, printed wiring boards, chip resistors, hybrid ICs, semiconductors, sealing materials for laminated boards, and bonding. Agents, paints and the like.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin curing accelerator of the present invention contains a triazole compound. The triazole compound is not particularly limited, and conventionally known compounds can be widely used. Examples thereof include 1,2,3-triazole, 1,2,4-triazole and the like, and a methyl group, an ethyl group, n A propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a linear or branched alkyl group having about 1 to 4 carbon atoms such as an isobutyl group, a mercapto group, an amino group, a phenyl group, an oxo group, Examples thereof include compounds in which one or two substituents such as a carboxyl group are substituted. Specific examples of such a triazole compound include, for example, 3-n-butyl-1,
2,4-triazole, 3,5-dimethyl-1,2,4
-Triazole, 3,5-di-n-butyl-1,2,4
-Triazole, 3-mercapto-1,2,4-triazole, 3-amino-1,2,4-triazole, 4-
Amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, 5-amino-1,2,4
-Triazole, 3-amino-5-phenyl-1,2,2
4-triazole, 3,5-diphenyl-1,2,4-
Triazole, 1,2,4-triazol-3-one,
Urazole (3,5-dioxy-1,2,4-triazole), 1,2,4-triazole-3-carboxylic acid and the like can be mentioned. In the present invention, as the triazole compound, 1,2,3-triazole, 1,2,2
4-Triazole, 3,5-dimethyl-1,2,4-triazole and the like are preferred, and 1,2,4-triazole is particularly preferred. In the present invention, the triazole compound is
The species can be used alone or two or more can be used in combination.

The curing accelerator for epoxy resin of the present invention includes:
Known curing accelerators such as tertiary amines and imidazoles may be contained within a range that does not impair the excellent effects.

The epoxy resin composition of the present invention contains an epoxy resin, a dihydrazide compound and the above-mentioned curing accelerator.

Known epoxy resins can be used, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, and cycloaliphatic epoxy. Resins, glycidyl ester-based epoxy resins, glycidylamine-based epoxy resins, heterocyclic epoxy resins, urethane-modified epoxy resins, brominated bisphenol A-type epoxy resins, and the like can be given. When the epoxy resin composition of the present invention is used as a sealing material for electronic parts, bisphenol A may be used among these epoxy resins.
Type epoxy resin, cresol novolak type epoxy resin and the like can be preferably used.

In the epoxy resin composition of the present invention, the dihydrazide compound to be used as a latent curing agent is not particularly limited as long as it has two or more hydrazide groups in one molecule. Can be widely used, for example, the general formula H ₂ NHN—X—NHNH ₂ (1) wherein X is a group —CO— or a group —CO— (A) _n —CO—
Is shown. A represents an alkylene group which may have a substituent or an arylene group which may have a substituent. n represents 0 or 1. And the like.

In the above general formula (1), examples of the alkylene group represented by A include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, and an octamethylene group. , A nonamethylene group, a decamethylene group, an undecamethylene group, a hexadecamethylene group, etc.
Linear alkylene groups. Examples of the substituent of the alkylene group include a hydroxyl group. Examples of the arylene group include a phenylene group, a biphenylene group, a naphthylene group, an anthrylene group, and a phenanthrylene group. Of these, a phenylene group, a naphthylene group, and the like are preferable. Examples of the substituent for the arylene group include a hydroxyl group, fluorine, chlorine, a halogen atom such as bromine, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group,
Examples thereof include a linear or branched alkyl group having about 1 to 4 carbon atoms, such as a tert-butyl group and an isobutyl group.

Specific examples of the dihydrazide compound represented by the general formula (1) include, for example, carbohydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, pimelic dihydrazide, suberic acid dihydrazide, and azelaine. Acid dihydrazide, sebacic dihydrazide, dodecanediohydrazide, hexadecandiohydrazide, maleic dihydrazide, fumaric dihydrazide, diglycolic dihydrazide, tartaric dihydrazide, malic dihydrazide, isophthalic dihydrazide, terephthalic dihydrazide, terephthalic dihydrazide , 4,
4'-bisbenzene dihydrazide, 1,4-naphthoic acid dihydrazide and the like can be mentioned. In addition to these, dibasic acid hydrazides such as dimer acid dihydrazide, 2,6-pyridine dihydrazide, iminodiacetic acid dihydrazide, citric acid trihydrazide, cyclohexanetricarboxylic acid trihydrazide, and dihydrazide compounds described in JP-B-2-4607. , 2,4-dihydrazino-
6-methylamino-sym-triazine, poly (meth)
Acrylic hydrazide and the like can also be used. Among these dihydrazide compounds, dibasic acid dihydrazide and the like are preferable, adipic acid dihydrazide, azelaic acid dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide, dodecane dihydrazide and the like are more preferable, and adipic acid dihydrazide, isophthalic acid dihydrazide and dodecanediodide. And the like are particularly preferred. Such dihydrazide compounds can be used alone or in combination of two or more. The amount of the dihydrazide compound to be used is not particularly limited and can be appropriately selected from a wide range depending on the use of the obtained epoxy resin cured product, but is usually about 5 to 80 parts by weight, preferably about 10 to 100 parts by weight of the epoxy resin. ~ 6
It may be about 0 parts by weight.

In the epoxy resin composition of the present invention, the use amount of the triazole compound as a curing accelerator is not particularly limited and can be appropriately selected from a wide range depending on the use of the obtained epoxy resin cured product. The amount is usually about 0.5 to 40 parts by weight, preferably about 5 to 20 parts by weight, per 100 parts by weight of a certain dihydrazide compound.

In the present invention, the triazole compound acts as a compatibilizer between the epoxy resin and the dihydrazide compound, and the dihydrazide compound is more uniformly dispersed in the epoxy resin. As a result, the desired effects of the present invention are exhibited. You.

In the epoxy resin composition of the present invention,
A monohydrazide compound as another curing accelerator can be used in combination with the curing accelerator of the present invention. As the monohydrazide compound, conventionally known compounds can be widely used, and examples thereof include a general formula RCONHNH ₂ (2) wherein R represents a hydrogen atom, an alkyl group, or an aryl group which may have a substituent. A monohydrazide compound represented by the formula:

In the general formula (2), examples of the alkyl group represented by R include a methyl group, an ethyl group, and an n group.
-A carbon number of 1 to 1 such as -propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group and n-undecyl group.
Twelve linear alkyl groups can be mentioned. Examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group and the like, and among these, a phenyl group is preferable. Examples of the substituent of the aryl group include, for example, a hydroxyl group, an amino group, a nitro group, a halogen atom such as fluorine, chlorine, and bromine, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, tert-
A linear or branched alkyl group having 1 to 4 carbon atoms such as a butyl group, an iso-butyl group, a methoxy group, an ethoxy group, n
-Propoxy group, iso-propoxy group, sec-propoxy group, n-butoxy group, iso-butoxy group, te
Examples thereof include a linear or branched alkoxy group having 1 to 4 carbon atoms such as an rt-butoxy group.

Specific examples of the monohydrazide compound (2) include, for example, lauric hydrazide, salicylic hydrazide, form hydrazide, acetohydrazide, propionic hydrazide, p-hydroxybenzoic hydrazide, p-methoxybenzoic hydrazide, and benzoic acid. Hydrazide, aminobenzoic acid hydrazide, 1-naphthoic acid hydrazide, 3-hydroxy-2-naphthoic acid hydrazide,
Anisic acid hydrazide and the like can be mentioned, and among them, lauric acid hydrazide and salicylic acid hydrazide can be particularly preferably used. In addition, lauric hydrazide and salicylic hydrazide have the characteristic of acting as a latent curing accelerator, though they are amine compounds. Such a monohydrazide compound may be used alone or in combination of two or more.

The amount of the monohydrazide compound used in the epoxy resin composition of the present invention is not particularly limited, but is usually 0.5 to 40 parts by weight based on 100 parts by weight of the dihydrazide compound as a curing agent. Degree, preferably about 5 to 25 parts by weight.

The epoxy resin composition of the present invention may contain inorganic fillers, reinforcing materials and the like which are conventionally added to epoxy resins. Known inorganic fillers can be used, for example, silica, fused quartz, calcium carbonate, barium carbonate, barium sulfate, hydrated alumina, alumina, magnesium hydrate, zircon, cordierite, silicon nitride, boron nitride, nitrided Aluminum and the like can be given. Known reinforcing materials can be used, and examples thereof include glass chop, asbestos, talc, and mica. It is known that the thermal conductivity, crack resistance, electrical properties, tracking resistance, and the like of the obtained cured product can be adjusted by appropriately changing the type, purity, and addition amount of the filler and the reinforcing material. However, the amount is usually about 55 to 160 parts by weight, preferably about 75 to 120 parts by weight, based on 100 parts by weight of the solid content of the epoxy resin. The filler and the reinforcing material can be used alone or in combination of two or more.

When the epoxy resin composition of the present invention is used, for example, as a sealing material for electronic parts, the epoxy resin, a dihydrazide compound as a curing agent, a curing accelerator of the present invention, and, if necessary, a monohydrazide compound A composition in which at least one kind of an inorganic filler, a reinforcing material, or the like is blended together with a curing accelerator such as the above.

If necessary, the epoxy resin composition of the present invention may contain the same additives as those conventionally contained in epoxy resin compositions. Here, as the additives, for example, inorganic pigments (titanium dioxide, carbon black, red iron oxide, yellow iron oxide, etc.), organic pigments, viscosity modifiers, leveling agents, defoamers, coupling agents, plasticizers,
Diluents, flame retardants, organic solvents and the like can be mentioned.

The epoxy resin of the present invention may further comprise an acid anhydride, an amine complex of boron trifluoride, dicyandiamide, imidazoles, a tertiary amine, or the like, as long as the remarkable effect of the curing accelerator of the present invention is not impaired. Conventional curing agents or curing accelerators such as carboxylic acids, chlorophenyl-1,1-N-dimethylurea, and organometallic compound salts can be added.

The epoxy resin composition of the present invention can be produced by appropriately mixing predetermined amounts of the above components according to a known method.

The epoxy resin composition of the present invention is, for example,
The present invention can be applied to articles of various shapes composed of at least one of various materials such as metals, synthetic resins, ceramics, fibers, papers, and wood. Specifically, for example, after immersing articles of various shapes in the epoxy resin composition of the present invention or applying or coating the epoxy resin composition of the present invention on the surface of the article, heating the epoxy resin of the present invention The composition may be cured. Curing conditions such as curing temperature and curing time may be appropriately selected according to various conditions such as the type of epoxy resin, the type and amount of dihydrazide compound used, and the type and amount of monohydrazide compound. It may be the same as a conventional epoxy resin composition using a dihydrazide compound as a curing agent (about 160 to 180 ° C. or higher).
A low temperature of about 0 to 140 ° C. may be used. Considering running costs, lower temperatures are preferred. The curing time may be usually about 1 to 30 minutes.

Further, the epoxy resin composition of the present invention can be formed into a molded article of an arbitrary shape according to a usual molding method such as cast molding or the like, and it can be used as it is, or it can be used as at least one of various materials. Can be attached to articles of various shapes constituted by the following methods, such as bonding, fitting, and mounting. The curing conditions at the time of molding may be the same as in the case of coating or coating.

[0033]

The present invention will be specifically described below with reference to examples and comparative examples. In the following, “parts” means “parts by weight”.

Examples 1 to 4 Bisphenol A type epoxy resin (trade name: Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.), curing agent (adipic dihydrazide, isophthalic acid) in the amounts (parts) shown in Table 1 Dihydrazide) and a curing accelerator (salicylic acid hydrazide, 1,2,4-triazole), 80 parts of silica and 30 parts of titanium dioxide are mixed, and the mixture is heated at 60 ° C. with a three-roll mill. Particle size 40μm
To obtain an epoxy resin composition of the present invention.

Comparative Examples 1 to 3 Epoxy resin compositions were produced in the same manner as in Examples 1 to 4, except that 1,2,4-triazole was not used.

Test Example 1 The epoxy resin compositions of Examples 1 to 4 and Comparative Examples 1 to 3 were heated to 120 ° C. or 140 ° C., and the time from the start of heating to solidification (gel time) was measured. Table 1 shows the results
Shown in

[0037]

[Table 1]

From Table 1, it is clear that the curing accelerator for epoxy resin of the present invention has an excellent curing promoting effect. It is also clear that the combined use of the epoxy resin effect accelerator of the present invention and a monohydrazide-based curing accelerator (salicylic acid hydrazide) can further enhance the curing acceleration effect.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-139998 (JP, A) JP-A-58-198525 (JP, A) JP-A-58-206622 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08G 59/50-59/60

Claims (2)

(57) [Claims] (1) an epoxy resin, (2) a dihydrazide compound
Epoxy resin composition comprising a product and (3) a curing accelerator for epoxy resin containing a triazole compound. 2. A further error epoxy resin composition according to <br/> claim 1, mono-hydrazide compound is blended.