JPS61213277A - Adhesive and flexible printed circuit board - Google Patents

Abstract

PURPOSE:An adhesive having improved adhesiveness, heat resistance, and smoothness, comprising specific components such as a phenolic resin, acrylonitrile- butadiene copolymer, epoxy resin, butyral resin, a fluorinated alkyl ester surface active agent, etc., in a specified ratio. CONSTITUTION:The aimed adhesive comprising (A) 10-50pts.wt. phenolic resin, (B) 35-70wt% acrylonitrile-butadiene copolymer, (C) 2-40pts.wt. epoxy resin, (D) 10-40wt% butyral resin, and based on 100pts.wt. mixture of the components A-D of (E) 0.03-0.1pt.wt. fluorinated alkyl ester surface active agent, and (F) 0.5-1.3pt.wt. alkyl ether surface active agent. A flexible printed circuit board having an adhesive layer consisting of the adhesive has an adhesive face free from unevenness, has improved roll and press molding properties and extremely improved appearance.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an adhesive that provides excellent adhesive strength, heat resistance, and smoothness and is used in the production of flexible printed circuit boards, and a flexible printed circuit board having this adhesive layer. This invention relates to printed circuit boards.

[Prior art]

Conventionally, NBR/phenol type adhesives (Japanese Patent Laid-Open No. 58-244767) have been known as adhesives for 7-lexiple printed circuit boards that provide high adhesive strength and heat resistance. However, when adhesive varnish is continuously applied to a plastic film and dried in a hot air dryer, sushi-like unevenness occurs in the continuous direction of the film, resulting in poor crimping when metal foil is crimped by roll lamination or press. may occur. In addition, there is a drawback that, after pressure bonding, unevenness occurs on the film surface, impairing the performance and appearance of the flexible printed circuit board.

[Purpose of the invention]

The inventors of the present invention have conducted intensive research to resolve the above-mentioned drawbacks of adhesives for flexible printed circuit boards, and have found that by adding a combination of a specific surfactant to NBV phenol, adhesive strength and soldering heat resistance can be improved. The inventors have discovered that it is possible to improve the appearance of the adhesive surface after application and drying without degrading it, and to significantly improve the press and roll adhesion properties of metal foils and the appearance of flexible printed circuit boards, and have arrived at the present invention.

[Structure of the invention]

The present invention provides: (1) An adhesive containing the following (a) to (f) (a) Phenol resin 10 to 50% by weight (b) Acrylonitrile-butadiene copolymer 35 to 70% by weight (c) Epoxy resin 2 ~40% by weight 0.
03 to 0.1 parts by weight (f) Alkyl ether surfactant 0.5 to 13 parts by weight (2) Flexible printed circuit board having an adhesive layer containing the following (a) to (f) (a) Phenol resin 10-50% by weight (d) Acrylonitrile-butadiene copolymer 35-70% by weight (c) Epoxy resin 2-40% by weight (d
) Butyl 2-yl resin 10-40% by weight of the above (
(e) 0.03 to 0.1 parts by weight of a fluorinated alkyl ester surfactant and (f) 0.5 to 13 parts by weight of an alkyl ether surfactant per 100 parts by weight of the mixture of a) to (d). It is something.

In order to obtain good results in the present invention, it is essential to mix the adhesive components in the above-mentioned proportions. For each component, the phenol resin of component (a) is 10 to 50% by weight.
It is necessary to do so. If it is less than 10% by weight, soldering heat resistance will be reduced, and if it exceeds 50% by weight, flexibility and adhesive strength will be reduced. If the acrylonitrile-butadiene copolymer (b) is less than 35% by weight, the adhesive strength and flexibility will decrease, and if it exceeds 70% by weight, the soldering heat resistance and solvent resistance will decrease. As the epoxy resin of component (c), usual ones such as bisphenol-based, resol-based, novolac-based, ether ester-based glycidyl ethers and cycloaliphatic epoxy compounds, and their brominated products can be used. If the epoxy resin is less than 2% by weight, the flow of the adhesive as a whole becomes small, making it difficult to bond uniformly with metal foil by hot press bonding, especially roll lamination, and making the soldering heat resistance unstable.

If it exceeds the percentage by weight of chrysanthemum, the flexibility will decrease. If the butyral resin as component (c) is less than 10% by weight, the adhesive strength and flexibility will decrease, and if it exceeds 40% by weight, the soldering heat resistance will decrease. (
Examples of the fluorinated alkyl ester surfactant as component e) include FC-430, FC-431 (trade name, manufactured by Sumikata 3M Company), S-141, S-145 (trade name, manufactured by Asahi Glass Company), etc. A combination of several types of fluorinated alkyl ester surfactants may be used.

In addition, diethylene alkyl ether, polyoxyethylene-alkyl allyl ether, polyoxyethylene polyoxypropylene ether, etc. can be used as the alkyl ether surfactant, and several types of alkyl ether surfactants can be used in combination. Anything is fine.

The i weight is 0 for the fluorinated alkyl ether surfactant.
．． It is necessary to adjust the content to 0.03 to 0.1% by weight.

If it is less than 0.03% by weight, there is no effect of smoothing the adhesive surface. If the amount exceeds 0.1% by weight, the adhesive varnish will foam significantly and the coating workability will deteriorate. The content of the alkyl ether surfactant must be 0.5 to 13% by weight. If it is less than 0.5% by weight, it will not be effective in eliminating foam generated by the fluorinated alkyl ester surfactant. Also,
If it exceeds 13% by weight, adhesive strength and soldering heat resistance will decrease.

Furthermore, the adhesive of the present invention (= is a flame-retardant inorganic compound such as antimony trioxide, aluminum hydroxide, barium borate, silica, alumina, mica, titanium oxide, zirconia, calcium silicate, magnesium hydroxide, oxidized Inorganic fillers such as magnesium, iron oxide, calcium carbonate, and silicon carbide may be contained in an amount of 45 parts by weight or less per 100 parts by weight of the adhesive.
If the amount exceeds the amount, the adhesive flow becomes small and roll 2
The lamination properties are reduced, and the adhesive strength is further reduced.

These inorganic fillers may be hydrophobically treated. Examples of processing agents include dimethyldic C10 silane, silicone oil, and hexamethylene dichrazan (HMDS).
, el, ~eta alkyltriethoxysilane, and methyltriethoxysilane.

Other than these (; glass cloth may be impregnated with it.Furthermore, various commonly used additives such as fillers, stabilizers, surfactants, solvents, etc. other than these may be blended depending on the purpose). It's okay.

The printed circuit board of the present invention includes plastic films (the second is polyimide film, polyester film, polyethylene film, polypropylene film, polyvinyl chloride film, etc.), and the metal foil mainly uses copper foil, but aluminum It may also be made of foil.

In addition to flexible steel clad plates obtained by heat-pressing these plastic films and metal foils with the adhesive of the present invention, there are also insulating coverlays for flexible printed circuits, multiple laminations of flexible printed circuits, and further (=hard reinforcement). This includes a printed circuit board using the above adhesive for adhesion to a board.

〔Effect of the invention〕

The present invention: By using an adhesive according to the present invention, it maintains excellent adhesive strength and heat resistance, eliminates the unevenness of the adhesive surface that was a conventional drawback, and improves roll or press moldability and flexible printed circuit boards. The appearance of the product has been significantly improved.

〔Example〕

According to the formulation table in Table 1, the solid content is 201% by weight.
After drying, apply it to a 30 μm thick film (Kapton manufactured by DuPout) and heat it at 130°C.
It was dried in a hot air dryer for 5 minutes. The surface coated with the adhesive was laminated with a copper foil roll having a thickness of 35 μm at a temperature of 160° C., a speed of 0.5 m/min, and a pressure of 3 pf/d. Next, kinearing was performed in an open environment at 120° C. for 12 hours to obtain a flexible steel clad plate. The smoothness of the adhesive surface after applying the adhesive and drying it and the quality of the obtained copper clad board are shown in Table 2 (=.

Claims (2)

[Claims] (1) An adhesive containing the following (a) to (f). (a) Phenol resin 10 to 50 weight (b) Acrylonitrile-butadiene copolymer 35 to
70% by weight (c) Epoxy resin 2-40% by weight (d) Butyral resin 10-40% by weight Based on 100 parts by weight of the mixture of (a) to (d) above, (e) Fluorinated alkyl ester surfactant 0 .0
3 to 0.1 parts by weight (f) Alkyl ether surfactant 0.5 to 13 parts by weight (2) A flexible printed circuit board having an adhesive layer including the following (a) to (f). (a) Phenol resin 10-50 weight, (b) Acrylonitrile-butadiene copolymer 35-50 weight
70% by weight (c) Epoxy resin 2-40% by weight (d) Butyral resin 10-40% by weight Based on 100 parts by weight of the mixture of (a) to (d) above, (e) Fluorinated alkyl ester surfactant 0 .0
3-0.1 parts by weight (f) Alkyl ether surfactant 0.5-1.3
Weight part