JP2002285127A - One-component adhesive for electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-component adhesive for electronic parts, suppressing a drawback of a conventional epoxy resin adhesive which is the lowering of the elastic modulus at a higher temperature than the Tg of the epoxy resin and enabling the improvement of heat resistance and adhesivity. SOLUTION: The adhesive composition composed of an epoxy resin, dicyandiamide and a cure accelerator further contains water and an epoxy silane as essential components. The present invention further relate to a cured product of the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component adhesive having excellent heat resistance and a cured product.

[0002]

2. Description of the Related Art Electronic components used in electric / electronic devices, communication devices, computers, computers, and the like are used as one of the constituent materials of electronic components because they are directly or indirectly affected by external temperature. The adhesive to be used is required to have high heat resistance. As the type of adhesive, there are a two-pack type in which the main agent / hardener is separated and a one-pack type in which the main agent / hardener is integrated. In the past, two-component adhesives were often used because the degree of freedom in material design was high, but in recent years there is no such drawback because the pot life is short and workability is often poor. One-component adhesive
It is increasingly being sought.

Conventionally, epoxy resins, unsaturated polyester resins, polyimide resins, phenol resins, polybismaleimide resins, and the like have been used as resins used for adhesives. Among them, epoxy resins are well-balanced in terms of heat resistance, adhesiveness, electrical properties, mechanical strength, moldability, cost, and the like, and are particularly widely used. As an example of a one-component adhesive using epoxy resin,
It is known that dicyandiamide is used as a curing agent, and has been widely used. However, it has been considered that it is difficult for the cured product to maintain its strength in a high-temperature portion exceeding Tg because the elastic modulus rapidly decreases at Tg. As a method to compensate for this drawback, a large amount of inorganic filler is blended to increase the elastic modulus of the cured product, increase the crosslink density by increasing the number of functional groups of the epoxy resin, or introduce bulky substituents into the epoxy resin, Techniques such as three-dimensionally regulating the structure of the cured product and increasing the temperature at which the cured product is transferred to the region above the rubber have been taken as far as possible, but in any case, the fundamental solution has not been reached.

On the other hand, silane alkoxides are chemically bonded to a system of bisphenol A type epoxy resin and tetraethylene pentamine (hereinafter abbreviated as TEPA) using a sol-gel reaction in order to improve the disadvantages of the cured epoxy resin. The method has been reported so far. Ochi et al. Of Kansai University, Abstracts of the 9th Polymer Material Forum Lectures (200
0 years), to TEP bisphenol A epoxy resin
A, When γ-glycidoxypropyltrimethoxysilane (hereinafter abbreviated as γ-GPS) is applied at a time, Tg disappears in dynamic viscoelasticity measurement, and a cured product having almost no decrease in elastic modulus is obtained. It has said. However,
TEPA has the disadvantage that the reactivity with the epoxy resin is so high that the reaction with the epoxy resin is started even at room temperature, and that the pot life is extremely short so that it cannot be made into one component as an adhesive.

Also, Goda et al. Of Arakawa Chemical proposed bisphenol A
An equivalent amount of a curing agent is added to a silane-modified epoxy resin obtained by chemically bonding a methoxysilane oligomer to a secondary hydroxyl group site of a type epoxy resin, and the mixture is dried and cured. It states that a cured product with little decrease in the rate can be obtained. In addition, a method using another similar method is disclosed in
JP, JP-A-2000-290350, JP-A-2000-
No. 281965 has been reported. The use of these techniques makes it possible to perform one-packing, but has the disadvantage that the raw material cost is increased because the silane-modified resin must be synthesized in advance.

[0006]

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide a one-part type adhesive for electronic parts which suppresses a decrease in the elastic modulus of a high-temperature portion exceeding Tg and has excellent heat resistance. .

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that a one-pack type adhesive composition containing an epoxy resin and dicyandiamide has a specific structure of epoxysilane. Is preferably expressed by the formula (1)
It has been found that it is effective to add at a content of 13 wt% or more and 18 wt% or less in the SiO ₂ content obtained in the above. Usually, epoxysilane as the silane coupling agent, for the purpose of improving the adhesion between the inorganic filler and the resin matrix used was added with SiO ₂ content of 0.5 to 1%. However, in the present invention, by adding an amount far greater than that to the dicyandiamide system, it is possible to suppress a decrease in the elastic modulus of the adhesive cured product in a high-temperature portion exceeding Tg, and to obtain a cured product excellent in heat resistance. Was found to be possible, and the present invention was completed.

[0008] That is, the present invention is a one-pack type adhesive for electronic parts, comprising an epoxy resin, dicyandiamide, water and an epoxysilane represented by the general formula 1 as essential components.

[0009]

Embedded image In the formula, R ₁ represents a CH ₃ or C ₂ H ₅ group.

[0010] Preferably, the one-pack type electronic device is characterized in that epoxysilane is added within a range of 13 wt% to 18 wt% in terms of SiO ₂ content obtained by the formula (1). It is an adhesive for parts.

[0011]

(Equation 2) In the formula, Mw: molecular weight of epoxy silane, χ: amount of epoxy silane added

Further, the present invention is a cured product obtained by heating any one of the above-mentioned adhesives for one-component electronic parts.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin used in the present invention includes, for example, bisphenol A type epoxy resin, alkyl substituted bisphenol A type epoxy resin, halogen substituted bisphenol A type epoxy resin, bisphenol F
Epoxy resin, alkyl substituted bisphenol F epoxy resin, halogen substituted bisphenol F epoxy resin, bisphenol S epoxy resin, glycidylamine epoxy resin, phenol novolak epoxy resin, cresol novolak epoxy resin, biphenyl epoxy resin, naphthalene Type epoxy resin and dicyclopentadiene type epoxy resin.

The amount of dicyandiamide used in the present invention is not particularly limited, but is preferably from 0.3 to 1 in terms of equivalent ratio with epoxy resin, more preferably from 0.4 to 0.
Between 6 is good. If the equivalent ratio is less than 0.3, the adhesive may not cure properly, which is not preferable. Also,
If the equivalent ratio is more than 1, unreacted dicyandiamide remains after curing, which is not preferable.

The epoxysilane used in the present invention is trimethoxysilane or triethoxysilane represented by the general formula (1). Formula (1)
It is preferable to add in the range of 13 wt% or more and 18 wt% or less in the SiO ₂ content obtained by the above.
When the content is less than 13% by weight, the same effect of improving the adhesion to the base material as that of a normal silane coupling agent can be obtained, but there is a possibility that the decrease in the elastic modulus of the adhesive in a high temperature portion exceeding Tg may not be suppressed. is there. If more than 18% by weight is added, the viscosity of the adhesive may drop sharply, in which case the adhesive will spread to other parts than the surface to be adhered, which is undesirable in terms of workability. .

With respect to the amount of water used in the present invention,
Although not particularly limited, epoxysilane 100 to be added
0.1 to 4 parts by weight based on parts by weight is preferred. More preferably, it is 0.6 to 2 parts by weight. If the amount is less than 0.1 part by weight, the hydrolysis reaction of the alkoxysilane in the epoxysilane is not promoted, which is not preferable.
If the amount is more than 4 parts by weight, residual moisture may cause defects such as voids and swelling during curing of the adhesive, which is not preferable.

The components that can be added to the adhesive for electronic parts of the present invention other than the above include the following additives. The type and amount of the curing accelerator that can be used in the present invention are not particularly limited. For example, trisdimethylaminomethylphenol (TAP), TA
P and octylic acid salts, imidazole derivatives, triphenylphosphine (TPP), quaternary salts of TPP, DBU salts and the like. The amount used is preferably 0.5 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, even more preferably 0.5 to 1 part by weight based on 100 parts by weight of the total epoxy resin. If the addition amount is less than 0.5 part by weight, the desired curing promoting action may not be obtained. If the amount is more than 5 parts by weight, the storage stability of the adhesive at room temperature may be impaired.

In the one-part type adhesive for electronic parts of the present invention, one or more solvents may be used, if necessary, for the purpose of adjusting the viscosity and uniformly mixing the components. The type of the solvent is not particularly limited.
-In addition to polar solvents such as dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, dioxane, and dimethyl sulfoxide, hydrocarbon solvents such as n-hexane, n-decane and cyclohexane, acetone, and methyl ethyl ketone , Ketone solvents such as methyl isobutyl ketone, ester solvents such as butyl acetate and benzyl acetate, methyl cellosolve, butyl cellosolve,
Examples include polyhydric alcohols such as methyl carbitol, ethyl carbitol, butyl carbitol, methyl cellosolve acetate, ethylene glycol, diethylene glycol, diglyme, and derivatives thereof.

The adhesive for one-package electronic components of the present invention may be combined with an inorganic filler as needed for the purpose of adjusting viscosity, imparting thixotropy, and reducing costs. The type of the inorganic filler is not particularly limited, and examples thereof include carbonates, sulfates, alumina, amorphous silica or spherical silica of various metals, titanium oxide, potassium titanate, and talc. Two or more can be used in combination. The amount of the inorganic filler to be added is not particularly limited as long as the adhesive in the present invention is in a liquid state and does not impair the fluidity.

It is desirable that the one-component adhesive for one-component electronic parts of the present invention be used by mixing the above components and kneading them sufficiently with a three-roll mill or the like.

[0021]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.

(Embodiment 1) 1. Preparation of adhesive composition 100 parts by weight of bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Epicoat 828), cresol novolak type epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc.)
Epiclone N-690-70M) 19 parts by weight, γ-GP
S (SH-6 manufactured by Dow Corning Toray Silicone Co., Ltd.)
040) Put 156 parts by weight in a beaker and stirrer 1
After stirring and mixing for 0 minutes, 1 part by weight of pure water was slowly dropped with a dropper. Thereafter, stirring was continued for 4 hours until the added water droplets completely disappeared. Next, 10% N, N-dimethylformamide of dicyandiamide (hereinafter referred to as DMF)
128% by weight of a solution and 10% D of 2-phenyl-4-methylimidazole (2P4MZ, manufactured by Shikoku Chemicals).
Two parts by weight of the MF solution were dropped with a dropper, and the mixture was further stirred for 30 minutes to obtain a resin composition having a SiO ₂ content of 14%. Further, this was returned to room temperature, 3 parts by weight of amorphous silica (manufactured by Nippon Aerosil Co., Ltd., R-972) and 100 parts by weight of titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., CR-EL) were added. The resulting mixture was kneaded to obtain an adhesive composition.

[Evaluation of Elastic Modulus] The thickness is 0.5 mm and one side is 10
The above-mentioned adhesive composition was poured into a chrome-plated mold molded into a square having a square of cm, and dried in a hot-air circulating oven at 90 ° C. for 1 hour and further at 150 ° C. for 2 hours. I got After returning this to room temperature, width 5m
m, cut into a size of 30 mm in length, using a dynamic viscoelasticity measuring device (Oriental Tech Co., Ltd.
The change in the elastic modulus was tracked using a frequency of 10 Hz, a temperature range of -150 to 260 ° C, and a heating rate of 2 ° C / min.
FIG. 1 shows the measurement results.

[Evaluation of Adhesion] Thickness 1.1 mm, width 1.5c
m, a 2 cm diameter circle was applied by screen printing to the center of an alkali-free glass (OA-2, manufactured by Nippon Electric Glass Co., Ltd.) having a length of 5 cm, and preliminarily dried at 90 ° C. for 1 hour. Non-alkali glasses of a shape were bonded so as to be orthogonal to each other, and further heated at 150 ° C. for 2 hours in a state where they were fixed under pressure. Next, the test piece was placed in a pressure cooker and treated under a high-temperature, high-humidity, high-pressure condition of 125 ° C. and 233 kPa for 24 hours, and the presence or absence of peeling was confirmed. Table 1 shows the results when the number of samples was five.

Example 2 Bisphenol A type epoxy resin (Epicoat 82 manufactured by Japan Epoxy Resin Co., Ltd.)
8) 100 parts by weight, cresol novolak type epoxy resin (Epiclon N-690-7, manufactured by Dainippon Ink and Chemicals, Inc.)
0M) 19 parts by weight and 326 parts by weight of γ-GPS (SH-6040 manufactured by Dow Corning Toray Silicone Co., Ltd.) were placed in a beaker, stirred and mixed with a stirrer for 10 minutes, and then 1 part by weight of pure water was slowly dropped with a dropper. . Thereafter, stirring was continued for 4 hours until the added water droplets completely disappeared. Next, 200 parts by weight of a 10% N, N-dimethylformamide (hereinafter abbreviated as DMF) solution of dicyandiamide and 2 parts by weight of a 10% DMF solution of 2P4MZ (manufactured by Shikoku Chemicals) were respectively dropped with a dropper, and further 30 minutes. Stirring was performed to obtain a resin composition having a SiO ₂ content of 18%. Further, the temperature was returned to room temperature, 3 parts by weight of amorphous silica (R-972, manufactured by Nippon Aerosil Co., Ltd.), and titanium oxide (CR-EL,
300 parts by weight (manufactured by Ishihara Sangyo Co., Ltd.) were added, and the mixture was kneaded with three rolls so as to be sufficiently uniform to obtain an adhesive composition.
Using this, elastic modulus evaluation and adhesion evaluation were performed in the same manner as in Example 1. The evaluation results are as shown in FIG.

Comparative Example 1 100 parts by weight of a bisphenol A type epoxy resin (Epicoat 828, manufactured by Japan Epoxy Resin Co., Ltd.), a cresol novolak type epoxy resin (Dai Nippon Ink Chemical Co., Ltd., Epicron N-690-7)
0M) 19 parts by weight were placed in a beaker, stirred and mixed with a stirrer for 10 minutes, and then 10% N, N-
Dimethylformamide (hereinafter abbreviated as DMF) solution
2 parts by weight of 2% by weight of a 2% by weight solution of 2P4MZ (manufactured by Shikoku Chemicals) was dropped with a dropper, and the mixture was further stirred for 30 minutes to obtain a resin composition having a SiO ₂ content of 0%.
The temperature was returned to room temperature, and 3 parts by weight of amorphous silica (R-972, manufactured by Nippon Aerosil Co., Ltd.) and titanium oxide (CR-E
L, manufactured by Ishihara Sangyo Co., Ltd.), and kneaded with a three-roll mill so as to be sufficiently uniform to obtain an adhesive composition. Using this, elastic modulus evaluation and adhesion evaluation were performed in the same manner as in Example 1. The evaluation results are as shown in FIG.

(Comparative Example 2) Bisphenol A type epoxy resin (Epicoat 82 manufactured by Japan Epoxy Resin Co., Ltd.)
8) 100 parts by weight, cresol novolak type epoxy resin (Epiclon N-690-7, manufactured by Dainippon Ink and Chemicals, Inc.)
0M), 19 parts by weight, and 35 parts by weight of dimethyldimethoxysilane (TSL-8112, manufactured by GE Toshiba Silicones Co., Ltd.) were placed in a beaker, stirred and mixed with a stirrer for 10 minutes, and then 1 part by weight of pure water was slowly dropped with a dropper. Thereafter, stirring was continued for 4 hours until the added water droplets completely disappeared. Next, 62 parts by weight of a 10% N, N-dimethylformamide (hereinafter abbreviated as DMF) solution of dicyandiamide and 2% of a 10% DMF solution of 2P4MZ (manufactured by Shikoku Chemicals) were added.
Each part by weight was dropped with a dropper, and the mixture was further stirred for 30 minutes to obtain a resin composition having a SiO ₂ content of 14%.
Further, the temperature was returned to room temperature, 3 parts by weight of amorphous silica (R-972, manufactured by Nippon Aerosil Co., Ltd.) and 300 parts by weight of titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) were added. The resulting mixture was kneaded to obtain an adhesive composition. Using this, elastic modulus evaluation and adhesion evaluation were performed in the same manner as in Example 1. The evaluation results are as shown in FIG.

Comparative Example 3 100 parts by weight of a bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Epicoat 828), a cresol novolak type epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc.)
19 parts by weight of Epiclone N-690-70M), methyltrimethoxysilane (GE Toshiba Silicone Co., Ltd., TSL-
8113) Put 62 parts by weight in a beaker and stirrer 1
After stirring and mixing for 0 minutes, 1 part by weight of pure water was slowly dropped with a dropper. Thereafter, stirring was continued for 4 hours until the added water droplets completely disappeared. Next, 10% N, N-dimethylformamide of dicyandiamide (hereinafter referred to as DMF)
Abbreviation) 62 parts by weight of the solution, 2P4MZ (Shikoku Chemicals)
2% by weight of a 10% DMF solution was dropped with a dropper, and the mixture was further stirred for 30 minutes to obtain an SiO ₂ content of 18%.
% Of the resin composition was obtained. Further, the temperature was returned to room temperature, and 3 parts by weight of amorphous silica (R-972, manufactured by Nippon Aerosil Co., Ltd.)
300 parts by weight of titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) was added, and the mixture was kneaded with a three-roll mill so as to be sufficiently uniform to obtain an adhesive composition. Using this, elastic modulus evaluation and adhesion evaluation were performed in the same manner as in Example 1. The evaluation results are as shown in FIG.

[0029]

[Table 1]

[0030]

The adhesive composition according to the present invention has a small decrease in the elastic modulus of the cured product in a high temperature range, and can maintain high adhesiveness even under high temperature and high humidity conditions.

[Brief description of the drawings]

FIG. 1 is a diagram showing a change in elastic modulus obtained by dynamic viscoelasticity evaluation in Examples and Comparative Examples.

Continuation of the front page F term (reference) 4J040 EC041 EC051 EC061 EC071 EC151 EC161 EK052 GA11 GA22 HC12 HC16 JA12 KA16 LA02 LA08 MA03 MA10 NA19 PA30

Claims (3)

[Claims] 1. A one-pack type electronic component adhesive comprising, as essential components, an epoxy resin, dicyandiamide, water and epoxysilane represented by the general formula (1). Embedded image In the formula, R ₁ represents a CH ₃ or C ₂ H ₅ group. 2. The one-part type according to claim 1, wherein the epoxysilane is added within a range of 13 wt% or more and 18 wt% or less in terms of SiO ₂ content obtained by the formula (1). Adhesive for electronic components. (Equation 1) In the formula, Mw: molecular weight of epoxy silane, χ: amount of epoxy silane added 3. A cured product obtained by heating the adhesive for one-component electronic components according to claim 1 or 2.