JP2869635B2 - Epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a curing accelerator for epoxy resins and an epoxy resin composition containing the curing accelerator. The epoxy resin composition of the present invention is particularly useful, for example, as a sealing material for electronic components.

[0002]

The cured epoxy resin has excellent electrical insulation, moisture resistance, heat resistance, solder resistance, chemical resistance, durability, adhesive strength, 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.

Conventionally, curing of an epoxy resin is performed by adding a curing agent to the epoxy resin. Here, as the curing agent, for example, aliphatic amines, acid anhydrides,
Phenol, imidazoles, dicyandiamide, amine complexes of boron trifluoride, dihydrazide compounds and the like are known.

When aliphatic amines, acid anhydrides and phenols are used among these conventional curing agents, the curing reaction proceeds even at room temperature, so that they must be mixed with an epoxy resin immediately before use, resulting in poor workability. There is a problem that is very bad. On the other hand, when any of an imidazole, dicyandiamide and an amine complex of boron trifluoride is used, since heating is indispensable, problems such as aliphatic amines do not occur, but imidazoles and dicyandiamide are used. The cured epoxy resin obtained by this method has insufficient moisture resistance. Further, 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. In addition, conventional curing agents other than dihydrazide compounds,
All have the disadvantage that a part thereof remains in the cured product as it is, releases ions such as hydrogen ions, and imparts electrical conductivity to the cured product. When such a cured product is used, for example, as a sealing material for electronic components, insulation failure occurs, and therefore, it is unavoidable that the reliability of electronic / electric devices is significantly reduced.

On the other hand, dihydrazide compounds do not cause a curing reaction at room temperature, do not impair the properties of the obtained cured product such as moisture resistance and electrical insulation, and do not induce discoloration. (JP-A-57-145121, JP-A-59-49224, JP-A-60-20927, JP-A-60-55025, and JP-A-60-55). 1
JP-A-77018, JP-A-61-12724, JP-A-61-36318, JP-A-60-12770
No. 2, JP-A-4-146980).

However, in order to carry out a smooth curing reaction using a dihydrazide compound, there is a problem that heating must be performed at 160 to 180 ° C. or higher, and a long time is required for curing. Therefore, energy costs and thus running costs are significantly increased, which is not industrially preferable. Therefore, in order to solve such a problem, a curing accelerator is usually added. Curing accelerators to be added when curing the resin using the dihydrazide compound include, for example, tertiary compounds such as tri-n-butylamine, benzylmethylamine, and 2,4,6-tris (dimethylaminomethyl) phenol. Amines, 2-ethylimidazole, 2-ethyl-4-methylimidazole, imidazoles such as 2-phenylimidazole and the like are used. However, these curing accelerators are the same or similar to conventional curing agents other than dihydrazide compounds,
Therefore, it is inevitable that the resulting cured product is given electrical conductivity.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have added a specific monohydrazide compound as a curing accelerator when curing an epoxy resin with a dihydrazide compound. This makes it possible to lower the curing temperature and shorten the curing time,
In addition, the inventors have found that an epoxy resin cured product that does not exhibit electrical conductivity even after long-term use and has further improved heat resistance, solder resistance, and the like can be obtained, and completed the present invention.

In the present invention, the general formula RCONHNH ₂ (1) wherein R represents an aryl group which may have a substituent. And a curing accelerator for epoxy resins comprising a monohydrazide compound represented by the formula:

The present invention also provides an epoxy resin composition containing an epoxy resin, a dihydrazide compound and a curing accelerator for epoxy resin represented by the above general formula (1) as active ingredients.

According to the present invention, there is provided an epoxy resin curing accelerator which does not impart electrical conductivity to the resulting cured epoxy resin. Since the curing accelerator of the present invention does not release ions such as hydrogen ions into the cured product, it does not impart electrical conductivity to the cured product. In particular, among the curing accelerators of the present invention, the curing accelerator represented by the following general formula (3) has a remarkable effect.

When the curing accelerator of the present invention is used, the curing temperature of the epoxy resin using a dihydrazide compound as a curing agent can be lowered by about 10 to 20 ° C. and the curing time can be shortened. The running cost can be significantly reduced, which is very useful industrially.

The epoxy resin cured product obtained by using the curing accelerator of the present invention has favorable properties inherent in the epoxy resin cured product (specifically, electrical insulation, moisture resistance, chemical resistance, durability, adhesion). Force, mechanical strength, etc.)
In particular, heat resistance, solder resistance and the like are further improved, and, as described above, even when used for a long period of time, no electrical conductivity is exhibited, and no insulation failure occurs. Therefore, when the epoxy resin cured product according to the present invention is applied to, for example, a sealing material for electronic components, high reliability can be imparted to electronic / electric devices.

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, sealing materials for laminates, adhesives, paints, and the like. Among them, sealing materials for electronic components such as capacitors, resistors, flyback transformers, magnetic heads, printed wiring boards, chip resistors, hybrid ICs, and semiconductors are preferable, and sealing materials for resistors and the like are particularly preferable.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The curing accelerator of the present invention has the general formula RCONHNH ₂ (1) wherein R represents an aryl group which may have a substituent. And a monohydrazide compound represented by the formula:

Here, the aryl group represented by R includes:
For example, a phenyl group, a tolyl group, a xylyl group, a naphthyl group and the like can be mentioned, and among these, a phenyl group is preferable.

Further, as a group to be substituted on the aryl group,
For example, a lower alkoxy group, a lower alkyl group, an amino group, a nitro group and the like can be mentioned. Among them, a lower alkoxy group and a lower alkyl group are preferable, and a lower alkoxy group is particularly preferable. Incidentally, the lower alkyl group is, for example, methyl, ethyl, n-propyl, isopropyl,
sec-propyl, n-butyl, isobutyl, tert
-Butyl or the like is a linear or branched alkyl group having about 1 to 4 carbon atoms, and the lower alkoxy group is methoxy, ethoxy, n-propoxy, isopropoxy, sec-propoxy, n-butoxy, isobutoxy, tert. A linear or branched alkoxy group having about 1 to 4 carbon atoms, such as butoxy.

Among the monohydrazide compounds of the above general formula (1),

[0018]

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[In the formula, R ¹ represents a lower alkyl group, an amino group or a nitro group. R ² represents a hydrogen atom or a lower alkoxy group. m shows the integer of 0-2. n shows the integer of 1-3. And the monohydrazide compound represented by the formula: Among these monohydrazide compounds, the monohydrazide compound in which R ² is a lower alkoxy group is characterized by having an ether bond in its molecular structure, and is particularly useful as a curing accelerator for an epoxy resin of the present invention. It is. None of the conventional curing accelerators for epoxy resins have an ether bond in their molecular structure. Among the monohydrazide compounds of the above general formula (2),

[0020]

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Wherein R ^{1 ′} represents a lower alkyl group. R ^{2 '}
Represents a lower alkoxy group. m and n are the same as above. ]
The monohydrazide compound represented by is preferable.

Specific examples of the above general formula (1) include, for example, benzoic acid hydrazide, 1-naphthoic acid hydrazide,
Anisic acid hydrazide, p-methoxybenzoic acid hydrazide, aminobenzoic acid hydrazide, 3-methoxy-2-naphthoic acid hydrazide and the like can be mentioned, and among them, anisic acid hydrazide can be particularly preferably used.

The monohydrazide compound represented by the general formula (1) can be easily produced according to a known method. For example, the corresponding carboxylic acid esters as starting materials and hydrazine are combined with methanol, ethanol, n-propanol, isopropanol, n-butanol, te
What is necessary is just to heat and reflux in an appropriate solvent such as a lower alcohol such as rt-butanol.

Next, the epoxy resin composition of the present invention will be described.

In the epoxy resin composition of the present invention, known epoxy resins can be used as the main component, and examples thereof include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, and phenol novolak. Epoxy resin, cresol novolak epoxy resin, cycloaliphatic epoxy resin, glycidyl ester resin, glycidylamine epoxy resin, heterocyclic epoxy resin, urethane-modified epoxy resin, brominated bisphenol A epoxy resin,
Heterocyclic epoxy resins and the like can be mentioned. When the epoxy resin composition of the present invention is used as a sealing material for electronic parts, bisphenol A type epoxy resin, cresol novolak type epoxy resin and the like can be preferably used among these epoxy resins.

[0026] In the epoxy resin composition of the present invention is not particularly limited as long as having two or more hydrazide groups in one molecule as a dihydrazide compound used as the curing agent, for example, the general formula H ₂ NHN-X-NHNH ₂ (4) wherein X is an oxo group, a group —CO—, or a group —CO-AC
O-shown. A represents an alkylene group which may have a substituent or an arylene group which may have a substituent. ]
And the like.

In the above formula (4), 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, 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, a phenanthrylene group and the like, and among 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 (4) include, for example, carbohydrazide,
Oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanediohydrazide, hexadecandiohydrazide, maleic acid dihydrazide, maleic acid dihydrazide, maleic acid dihydrazide Acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 4,4'-
Bisbenzene dihydrazide, 1,4-naphthoic acid dihydrazide and the like can be mentioned. Besides these, dimer acid dihydrazide, 2,6-pyridine dihydrazide,
Iminodiacetic acid dihydrazide, citric acid trihydrazide,
Cyclohexanetricarboxylic acid trihydrazide, dihydrazide compound described in JP-B-2-4607, etc.
Basic acid hydrazide, 2,4-dihydrazino-6-methylamino-sym-triazine, poly (meth) acrylic acid hydrazide and the like can also be used. When the epoxy resin composition of the present invention is used as a sealing material for electronic parts,
Among these dihydrazide compounds, dibasic acid dihydrazide and the like are preferable, adipic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanediohydrazide and the like are particularly preferable, and dodecanediohydrazide and the like are more preferable. The dihydrazide compound is 1
The species 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.
The amount may be about 80 parts by weight, preferably about 10 to 60 parts by weight.

In the epoxy resin composition of the present invention, the monohydrazide compound of the above general formula (1) used as a curing accelerator may be used alone or in combination of two or more. The amount 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 40 parts by weight, based on 100 parts by weight of the dihydrazide compound as a curing agent. Preferably 10
It may be about 20 parts by weight.

The epoxy resin composition of the present invention may contain inorganic fillers, reinforcing materials, and the like which have been conventionally added to epoxy resins. Known 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, aluminum nitride And the like. Known reinforcing agents 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 may 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, and a monohydrazide compound of the above general formula (1) as a curing accelerator Along with
A composition containing at least one kind of inorganic filler, reinforcing agent and the like is preferable.

The epoxy resin composition of the present invention may contain, if necessary, 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.

Further, the epoxy resin composition of the present invention comprises
As long as the remarkable effects of the present invention are not impaired, imidazoles, tertiary amines, carboxylic acids, chlorophenyl-1,
Conventional curing agents or curing accelerators such as 1-N-dimethyl urea and organometallic compound salts can also be added.

The epoxy resin composition of the present invention can be produced by mixing 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 and papers. Specifically, articles of various shapes may be immersed in the resin composition of the present invention or coated or coated with the resin composition of the present invention on the surface of the article, and then heated to cure the resin composition of the present invention. . 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. Usually, 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), and may be a temperature lower by about 10 to 20 ° C. Considering running costs, lower temperatures are preferred. The curing time may be generally about 1 to 10 minutes.

Further, the epoxy resin composition of the present invention is formed into a molded article having an arbitrary shape according to a usual molding method such as cast molding, and the molded article is formed into articles of various shapes composed of at least one of various materials. It can also be attached according to a usual method such as bonding and fitting. The curing conditions at the time of molding may be the same as those for coating or coating.

[0037]

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

Example 1 100 parts of bisphenol A type epoxy resin (trade name: Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.), 30 parts of dodecandiohydrazide, 6 parts of anisic acid hydrazide,
80 parts of silica and 30 parts of titanium dioxide are mixed in advance, and the mixture is heated to 60 ° C. on a three-roll mill at a particle size of 40 μm.
m and dispersed and kneaded to produce an epoxy resin composition of the present invention.

Comparative Example 1 An epoxy resin composition was produced in the same manner as in Example 1 except that the amount of dodecandiohydrazide was changed to 35 parts and no anisic acid hydrazide was used.

Comparative Example 2 An epoxy resin composition was produced in the same manner as in Example 1 except that the blending amount of anisic acid hydrazide was changed to 45 parts and dodecandiohydrazide was not used.

Test Example 1 (Heat Resistance Test) The glass transition temperature (Tg, ° C.) of the epoxy resin compositions obtained in Example 1 and Comparative Examples 1 and 2 was measured by measuring the change in the coefficient of linear expansion. (TAM method). Also,
The temperature at which a normal cured product was obtained after heating for 1 hour was defined as the curing temperature of the composition, and the curing temperature of each epoxy resin composition was examined. Table 1 shows the results.

Test Example 2 (Solder Resistance Test) The epoxy resin compositions obtained in Example 1 and Comparative Examples 1 and 2 were poured into a mold having dimensions of 1 cm × 1.5 cm × 3 cm. After heating for a minute, a cured product for testing was produced. The test piece was immersed in solder maintained at 350 ° C. for 5 seconds after being melted by heating, taken out, and visually observed for the degree of discoloration of the test piece. The evaluation criteria are as follows.

：: No crack was generated on the surface, and only slight discoloration was observed.

Δ: Discoloration is deep.

X: The whole or part is carbonized.

The results are shown in Table 1 below.

[0047]

[Table 1]

From the above results, by adding anisic acid hydrazide, a curing accelerator for epoxy resin of the present invention, the curing temperature is lowered by 10 ° C. or more, the Tg is increased by 35 ° C. or more, and the heat resistance is lowered. It can be seen that a cured product which is remarkably excellent and further excellent in solder resistance can be obtained. That is, the synergistic effect of the combined use of dodecandiohydrazide (curing agent) and anisic acid hydrazide (curing accelerator) can be clearly confirmed.

Test Example 3 The compositions for epoxy resins obtained in Example 1 and Comparative Examples 1 and 2 were subjected to the following performance tests. Table 2 shows the results.

(1) Storage stability: A sample was placed in a glass bottle having a depth of 80 mm and a cross-sectional diameter of 60 mm to a depth of 70 mm, sealed, and stored in a thermostat at 40 ° C. for 30 days. The viscosity before and after storage is measured using a Lion Visco Tester (20
° C, unit poise). A case where the viscosity after storage was not more than about 1.5 times the viscosity before storage was determined to be acceptable.

(2) Painting workability and appearance: 1 / 4W type 1M
A sample adjusted to 25 ° C. was applied to a Ω carbon film fixed resistor, and cured by heating at 170 ° C. for 10 minutes. A sample was evaluated as pass if there was no sagging during coating, the thickness of the cured coating film was 200 μm or more, and no pinholes or cracks were observed on the coating film surface.

(3) Moisture resistance: A resistor coated in the same manner as in the above (2) was supplied with electricity for 5 hours (250 VDC) in an atmosphere of 85 ° C. and 85% relative humidity for 0.5 hour. The non-energization was defined as one cycle, and 250 cycles were repeated. The resistance value before and after the test was measured, and the rate of change (%) of the resistance value after the test with respect to the initial resistance value was examined. A case where the rate of change is within ± 5% is a pass.

(4) Heat resistance: The resistor coated in the same manner as in (2) above was allowed to stand in a thermostat at 155 ° C. for 1000 hours. After the test, no cracks were observed on the coating film surface, and the rate of change (%) of the resistance value after the test to the resistance value before the test was examined. A case where the rate of change is within ± 1% is a pass.

(5) Durability (cooling / heat cycling): A resistor coated in the same manner as in (2) above was tested at 125 ° C. × 30.
Min, 25 ° C x 10 min, -55 ° C x 30 min.
Five cycles were repeated. After the test, no cracks were observed on the coating film surface, and the rate of change (%) of the resistance value after the test to the resistance value before the test was examined. ± 1 change rate
% Is a pass.

(6) Insulation resistance: A resistor painted in the same manner as in (2) above was placed inside a right-angled metal V block.
Both ends were placed so as not to protrude, and a DC voltage of 500 V was applied between the V block and the lead wire for 2 minutes to measure a resistance value. A case where the resistance value was 10,000 MΩ or more was regarded as a pass.

[0056]

[Table 2]

From the above results, the cured product of the epoxy resin according to the present invention has the same or better performance than the cured product of the conventional epoxy resin (Comparative Example 1) in properties other than heat resistance and solder resistance. It is clear that you are.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Yoshihisa Tomotaki 463 Kagasuno, Kawauchi-machi, Tokushima City, Tokushima Prefecture Inside the Otsuka Chemical Co., Ltd. Tokushima Plant (56) References JP-A-48-67399 (JP, A) JP-A Sho 61-266483 (JP, A) JP-A-4-126714 (JP, A) JP-A-9-31165 (JP, A) JP-A-9-48877 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08G 59/54-59/60

Claims (1)

(57) [Claims] 1. An epoxy resin having dihydra as a curing agent.
The disilazide compound, anisic acid hydrazide as a curing accelerator
An epoxy resin composition obtained by blending .