JPH06200228A - One-pack adhesive for formation of electronic circuit - Google Patents

Abstract

PURPOSE:To provide the subject adhesive which has adhesive strength sufficient to inhibit the release of the bonded component and does not string even when delivered at a high speed. CONSTITUTION:The objective adhesive comprises 100 pts.wt. total of a triepoxy resin, a diepoxy resin and a monoepoxy resin, 2-30 pts.wt. imidazole curing agent, 30-80 pts.wt. inorganic filler, 5-20 pts.wt. thixotropic agent, and 0.01-5 pts.wt. organic pigment.

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 for forming an electronic circuit for fixing an electronic component to form an electronic circuit on a substrate.

[0002]

2. Description of the Related Art In recent years, a one-component adhesive for forming an electronic circuit comprises a modified acrylic resin, a photopolymerization initiator and a thermosetting agent, a filler such as silane coupling talc, and a colorant. It has been known.

Further, Japanese Unexamined Patent Publication No. 1-2493 discloses that
It is disclosed that it is composed of a functional epoxy resin, an amine adduct type curing agent, a benzylidene sorbitol type or bentonite type thixotropic agent, an inorganic filler, a colorant and the like.

[0004]

However, although the one using the above-mentioned acrylic resin is excellent in the dispensing property, it has a problem that the adhesive strength is low.

Further, in the case of using a bifunctional epoxy resin, sufficient adhesive strength cannot be obtained when the adhesive is heat-cured in a short time, and the adhesive strength is remarkably lowered especially at high temperature, so that the adhesive adheres to the substrate. There is a problem in that the electronic parts that have been removed are missing.

Further, since the bifunctional epoxy resin is a viscous material and the adhesive containing the benzylidene sorbitol type or bentonite type thixotropic agent is not sufficiently effective in improving the thixotropy, the adhesive is adhered when it is discharged at a high speed. There is a problem that the agent draws a thread, which adheres to a substrate electrode or the like to make soldering impossible.

In view of the above-mentioned problems of the prior art, the present invention has an excellent adhesive strength, does not drop parts, and does not pull a thread when the adhesive is discharged at a high speed, and has an excellent quality. An object of the present invention is to provide a one-component adhesive for forming an electronic circuit, which can be manufactured.

[0008]

A one-part adhesive for forming an electronic circuit according to the present invention comprises a trifunctional epoxy resin, a bifunctional epoxy resin, a monofunctional epoxy resin, an imidazole-based curing agent, an inorganic filler, a thixotropic agent, and A one-component adhesive for forming an electronic circuit containing an organic pigment, the total amount of a trifunctional epoxy resin, a bifunctional epoxy resin and a monofunctional epoxy resin being 1
It is characterized by containing 2 to 30 parts by weight of an imidazole-based curing agent, 30 to 80 parts by weight of an inorganic filler, 5 to 20 parts by weight of a thixotropic agent, and 0.01 to 5 parts by weight of an organic pigment with respect to 00 parts by weight. .

Preferably, at least one of the trifunctional epoxy resin and the bifunctional epoxy resin is a solid amorphous form (amorphous powder) at room temperature, and the thixotropic agent is at least one of amide wax and anhydrous silica fine powder. Including the above.

[0010]

According to the above constitution of the present invention, the inclusion of the trifunctional epoxy resin improves the high temperature adhesive strength, and the inclusion of the monofunctional epoxy resin excels in the dispensing property.
In addition, since the imidazole-based curing agent is used, the curing can be performed at high speed, and the thixotropic agent improves the dispensing property and prevents the stringing. Particularly, if the thixotropic agent is less than 5 parts by weight based on 100 parts by weight of the total amount of the epoxy resin, a sufficient effect cannot be obtained, and if it is more than 20 parts by weight, the adhesive strength is lowered and the stringing prevention effect is also lowered. By adjusting the amount to 20 parts by weight, it is possible to improve the adhesive strength and prevent stringing, and if the amount of the imidazole-based curing agent is less than 2 parts by weight, it will not be sufficiently cured.
If the amount is more than 0 parts by weight, the composition may be excessively hardened and the storage stability may be deteriorated. Thus, by using the adhesive of the above composition, there is no missing of parts in the electronic circuit, and since the thread is not pulled even at high speed discharge, the soldering quality is not affected, and an excellent electronic circuit board is manufactured. it can.

Further, preferably, at least one of the epoxy resins is in a solid amorphous form at room temperature to improve the dispenseability, and the thixotropic agent is at least one of amide wax or anhydrous silica ultrafine powder. As a result, the adhesive strength and the dispenseability can be further improved.

[0012]

EXAMPLES Examples of the one-component adhesive for forming an electronic circuit of the present invention will be described below.

The contents of the components used in the following are as follows.

Epoxy resin A: Epicoat YX-4
(Okaka Shell Epoxy Co., Ltd.) (Epoxy equivalent 104 glycidylamine type trifunctional epoxy resin) Epoxy resin B: Epicoat 806 (Okaka Shell Epoxy Co.) (epoxy equivalent 165 bisphenol F)
Type epoxy resin, compounded as a bifunctional epoxy resin) Epoxy resin C: reactive diluent YED122 (manufactured by Yuka Shell Epoxy Co., Ltd.) (compounded as a monofunctional epoxy resin with an alkylphenol monoglycidyl ether having an epoxy equivalent of 220 to 250). Epoxy resin D: Araldite ECN1273 (manufactured by Nippon Ciba Geigy) (polyfunctional epoxy resin having an epoxy equivalent of 210 to 230 and compounded as a trifunctional epoxy resin) Epoxy resin E: Araldite XAC5007 (manufactured by Nippon Ciba Geigy) (epoxy equivalent 600-700) Compounded as a bifunctional epoxy resin) Hardener: Epicure MI-2-AZ (manufactured by Yuka Shell Epoxy Co., Ltd.) (2-methylimidazole azine having a melting point of 246 to 252 ° C) Filler: Cyprabond ( Japan Mistron (Manufactured) (silane coupling treatment talc having an average particle size of 2.3 μm) Thixotropic agent A: Disparon A603-20X
(Kusumoto Kasei Co., Ltd.) (Fatty acid amide wax type) Thixotropic agent B: Aerosil No. 200 (manufactured by Nippon Aerosil Co., Ltd.) Facial agent: Carmine 6B (manufactured by Dainippon Ink and Chemicals) In addition, the measurement methods and evaluation of physical properties shown in Table 3 The method is as follows.

Stringing occurrence rate: 100 points of adhesive were continuously applied to a printed circuit board at a speed of 1 point for 0.12 seconds by an adhesive applicator, and a point a at which the coating shape was a threading state was measured. , (A [point] / 100 [point]) × 100 [%] is defined as the stringing occurrence rate [%].

Attachment strength: JIS K 685
According to the measurement of 0.

(Examples 1 to 3 and Comparative Examples 1 to 4) Table 1
Adhesives were prepared by sufficiently stirring the components according to the formulations shown in (Examples) and Table 2 (Comparative Examples). The component composition in each example is parts by weight.

When the characteristics of these adhesives were examined, the results shown in Table 3 were obtained.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

From Table 3, thixotropic agents A and B are 30
In Comparative Examples 1 to 3 with more than 20 parts by weight, the stringing occurrence rate is about 20 times that in each Example with 20 parts by weight or less, and the adhesive strength is reduced to about 60 to 70%. Also, in Comparative Example 4 not containing the trifunctional epoxy resin, the threading occurrence rate was similarly high and the adhesive strength was low as compared with each Example.

[0023]

According to the present invention, since the high temperature adhesive strength is improved by containing the trifunctional epoxy resin as described above, and the imidazole type curing agent is used, the curing can be performed at a high speed, and the dispensing with the thixotropic agent is performed. Of the thixotropy agent to improve the adhesive strength and prevent the stringing. Therefore, by using this adhesive, it is possible to prevent stringing. Since there are no missing parts and the yarn is not pulled even at high speed ejection, the soldering quality is not affected and an excellent quality electronic circuit board can be manufactured.

Further, preferably, at least one or more of the epoxy resins are in a solid amorphous form at room temperature, and the thixotropic agent is at least one or more of amide wax or anhydrous silica ultrafine powder to further improve adhesive strength and dispense. It is possible to improve the property.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hachiro Nakai, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A one-component adhesive for forming an electronic circuit, comprising a trifunctional epoxy resin, a bifunctional epoxy resin, a monofunctional epoxy resin, an imidazole-based curing agent, an inorganic filler, a thixotropic agent, and an organic pigment. Total amount of functional epoxy resin, bifunctional epoxy resin and monofunctional epoxy resin 10
2 to 30 parts by weight of an imidazole-based curing agent, 30 to 80 parts by weight of an inorganic filler, 5 to 20 parts by weight of a thixotropic agent, and 0.01 to 5 parts by weight of an organic pigment, based on 0 parts by weight. A one-part adhesive for forming electronic circuits. 2. The one-component adhesive for forming an electronic circuit according to claim 1, wherein at least one of the trifunctional epoxy resin and the bifunctional epoxy resin has a solid amorphous form at room temperature. 3. The one-component adhesive for forming an electronic circuit according to claim 1, wherein the thixotropic agent contains at least one of amide wax and anhydrous silica fine powder.