JPH05347477A - Adhesive composition for flexible printed circuit substrate - Google Patents

Abstract

PURPOSE:To acquire an FPC substrate having good adhesion, thermal resistance, folding resistance and operativity in semi-hardened state. CONSTITUTION:An adhesive composition for a flexible printed circuit substrate whose essential elements are (A) thermosetting resin, (B) acrylonitrile-butadiene rubber and (C) N,N'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)--propionyl] hydrazine as metal deactivator and which is formed by mixing the metal deactivator of (C) by 0.01 to 5wt.% to adhesive composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly applicable to adhesiveness, heat resistance,
The present invention relates to an adhesive composition for a flexible printed circuit board, which is excellent in folding resistance and workability in a semi-cured state.

[0002]

2. Description of the Related Art In recent years, demands for smaller, lighter and faster electronic devices have been increasing. A flexible printed circuit board (hereinafter referred to as an FPC board) is lightweight and can be mounted three-dimensionally, which is very advantageous for such requirements. A coverlay sheet is usually laminated and adhered on the circuit to the FPC substrate for the purpose of preventing oxidation of the circuit and improving flexibility. The adhesive of the coverlay sheet is required to have adhesiveness, heat resistance, flexibility, electrical insulation, circuit embedding properties during lamination processing, workability, and storage stability in a semi-cured state. Conventionally, as an adhesive satisfying these requirements, acrylonitrile butadiene rubber / phenol resin type, acrylonitrile butadiene rubber / epoxy resin type, carboxy-containing acrylonitrile butadiene rubber /
Adhesives such as epoxy resin type and acrylic rubber / epoxy resin type are used.

However, in an adhesive using an acrylonitrile butadiene rubber, a carboxy-containing acrylonitrile butadiene rubber, etc., copper forming a circuit serves as a catalyst for thermal deterioration when the solder is dipped, the acrylonitrile butadiene rubber is oxidized and deteriorated, and the solder There is a drawback that the adhesive strength after immersion is significantly reduced. Also, with an adhesive that uses acrylic rubber, there is little deterioration due to such heating,
When it is used as a coverlay, it has a drawback that it is largely sticky in a semi-cured state and has poor workability in the processing step, and that it has poor folding endurance when used as an FPC substrate.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and is for a flexible printed circuit board excellent in adhesiveness, heat resistance, folding resistance and workability in a semi-cured state. It is intended to provide an adhesive composition.

[0005]

As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by using a specific metal deactivator, and the present invention Has been completed.

That is, the present invention provides (A) a thermosetting resin,
(B) Acrylonitrile-butadiene rubber and (C) N, N′-bis [3- (3,5-dit-butyl-4-hydroxyphenyl) propionyl] hydrazine represented by the following structural formula as a metal deactivator:

[0007]

[Chemical 2] Is an essential component, and 0.01 to 5% by weight of the metal deactivator (C) is blended with the adhesive composition to provide an adhesive composition for a flexible printed circuit board.

The present invention will be described in detail below.

Examples of the thermosetting resin (A) used in the present invention include phenol resins, epoxy resins, polyester resins, polyimide resins, and modified resins thereof. These are used alone or in admixture of two or more. can do. These thermosetting resins can be usually used by dissolving them in a solvent. The solvent should be one that dissolves the thermosetting resin and synthetic rubber, but the boiling point should be 150 to prevent the solvent from remaining in the adhesive coating and drying process.
It is desirable that the solvent is not more than ° C. Specific solvents include methyl ethyl ketone, toluene, acetone, ethyl cellosolve, methyl cellosolve, etc. These may be used alone or in admixture of two or more.

The (B) acrylonitrile butadiene rubber used in the present invention includes an acrylonitrile butadiene rubber and a modified rubber thereof, and the nitrile content, the degree of polymerization, the terminal group and the like can be used without limitation, and these can be used alone or A mixture of two or more species can be used. Specifically, for example, Nipol 1432J, Nipol 1
072 (manufactured by Zeon Corporation, trade name) and the like.

The (C) metal deactivator used in the present invention is N, N'-bis [3- (3,5-dit-) having the following chemical formula.
Butyl-4-hydroxyphenyl) propionyl] hydrazine is used.

[0012]

[Chemical 3]

Specific compounds include Irganox MD1024 (trade name, manufactured by Ciba-Geigy Co., Ltd.), which are used alone or in admixture with two or more kinds of deterioration inhibitors and antioxidants. be able to. This metal deactivator is used as a deterioration inhibitor for the above-mentioned acrylonitrile butadiene rubber, and its compounding ratio is preferably 0.01 to 5% by weight based on the whole adhesive composition. If the compounding amount is less than 0.01% by weight, the effect of preventing thermal deterioration of the rubber is not obtained, and if it exceeds 5% by weight, the effect is not improved so much and it is economically disadvantageous.
In addition, the adhesive strength is unfavorably deteriorated.

The FPC board adhesive composition of the present invention contains a thermosetting resin, an acrylonitrile butadiene rubber and a specific metal deactivator as essential components, but is necessary insofar as the object of the present invention is not impaired. In addition, fine powder inorganic or organic fillers, pigments, etc. can be added and blended. Each of these components can be uniformly dissolved using a solvent such as methyl ethyl ketone / toluene to easily produce a solution of an adhesive composition for an FPC board (hereinafter referred to as an adhesive). This adhesive can be used not only for FPC substrates and FPC coverlays, but also for bonding copper-clad laminates to copper foil / substrate, and in other cases.

[0015]

The FPC board adhesive composition of the present invention prevents heat deterioration of the acrylonitrile butadiene rubber due to the catalytic action of copper during solder dipping by incorporating a specific metal deactivator, resulting in solder dipping. It is possible to reduce a decrease in adhesiveness later. Further, since acrylic rubber is not used as a synthetic rubber component, stickiness in the semi-cured state can be reduced and excellent folding resistance can be achieved.

[0016]

EXAMPLES The present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, "parts" means "parts by weight".

Example 1 45 parts of carboxy-containing acrylonitrile-butadiene rubber Nipol 1072 (manufactured by Nippon Zeon Co., Ltd.), brominated epoxy resin YDB-400 (trade name manufactured by Tohto Kasei Co., Ltd.,
Epoxy equivalent 400) 40 parts, 4,4'-diaminodiphenyl sulfone (amine equivalent 62) 5 parts, boron trifluoride monomethylamine 1.2 parts, aluminum hydroxide Hydilite H-43M (manufactured by Showa Denko KK, trade name) 10 parts, and 0.3 parts of a metal deactivator, Irganox MD1024 (manufactured by Nippon Ciba Geigy, trade name), with methyl ethyl ketone /
Dissolved and diluted in a mixed solvent of toluene = 6/4, solid content 30%
The adhesive composition for FPC board of was manufactured.

Comparative Example 1 In Example 1, the metal deactivator Irganox MD was used.
An adhesive for FPC boards was manufactured in the same manner as in Example 1 except that 1024 (manufactured by Japan Ciba-Geigy, trade name) was not mixed.

Comparative Example 2 In Example 1, acrylonitrile butadiene rubber Nipol 1072 (manufactured by Nippon Zeon Co., Ltd.) was used in place of acrylic rubber Nipol AR51 (manufactured by Nippon Zeon Co., Ltd.). Irganox MD1024, a metal deactivator (trade name, manufactured by Nippon Ciba Geigy)
F in the same manner as in Example 1 except that no F was added.
An adhesive for PC board was manufactured.

FP manufactured in Examples and Comparative Examples 1 and 2
The adhesive composition for C substrate is a 25 μm thick polyimide film Kapton (trade name, manufactured by EI DuPont).
Was coated with a roll coater to a thickness of 38 μm to prepare a coverlay sheet. The cover lay sheet and a flexible copper clad laminate having a test pattern formed by the subtract method are used at a temperature of 160 ° C. and a pressure of 30 kg / c.
Laminated by hot press under conditions of m ² and 30 minutes, and FP
A C substrate was manufactured. The obtained FPC board was tested for peeling strength, folding resistance, electric insulation and tackiness. The results are shown in Table 1. The adhesive composition for a flexible printed circuit of the present invention was excellent in all properties, and the effects of the present invention could be confirmed.

[0021]

[Table 1] * 1: According to IPC-FC-240B. * 2: According to JIS-P-8115. * 3: Measured with a 1 mm interval comb test pattern. * 4: ○: No stickiness, ×: There is stickiness.

[0022]

As is clear from the above description and Table 1, the adhesive composition for a flexible printed circuit board of the present invention is excellent in adhesiveness, heat resistance, folding resistance and workability in a semi-cured state. In addition, various properties required for the FPC board such as electric insulation are not deteriorated, which contributes to the manufacture of a highly reliable FPC board suitable for a bending movable part of an electronic device.

Claims (1)

[Claims] 1. A thermosetting resin (A), (B) acrylonitrile butadiene rubber, and (C) a metal deactivator represented by the following structural formula:
N′-bis [3- (3,5-dit-butyl-4-hydroxyphenyl) propionyl] hydrazine embedded image An adhesive composition for a flexible printed circuit board, characterized in that 0.01 to 5% by weight of the metal deactivator (C) is blended with the adhesive composition as an essential component.