JPS62242529A - Substrate for flexible printed circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a printed circuit board made of a polyether sulfone film and a metal foil, which has an adhesive layer having excellent adhesive strength and heat resistance. This invention relates to printed circuit boards.

[Prior art and problems]

BACKGROUND ART In recent years, with the development of the electronics and electrical industry, there has been a demand for simpler, smaller, more reliable, and higher performance mounting methods for communication, consumer, and other equipment, and the use of printed wiring boards has become desirable. In particular, the use of flexible printed circuit boards made of plastic films that are lightweight and can be mounted three-dimensionally is advantageous and is attracting attention.

There are various types of plastic films, but polyimide films, polyester films, etc. are common. However, although polyimide films have excellent mechanical, electrical, and chemical properties, they have the disadvantage of being very expensive.

On the other hand, polyester film has poor heat resistance, so low melting point solder is used, but this solder has poor solderability compared to crystalline solder, has inferior adhesive strength, and is generally less reliable. A film made of polyether sulfone has been attracting attention as an improved film, but its adhesion to metal foil has been a problem. A good adhesive was desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide a flexible printed circuit board made of a polyether sulfone film and metal foil having an adhesive layer having excellent adhesive properties, heat resistance, and flexibility.

[Means action to solve the problem]

The present invention provides a flexible printed circuit board made of a polyether sulfone film and a metal foil, in which (i) an epoxy resin 100 having a number average molecular weight of 1,500 to 4,000 and having two epoxy groups in one molecule; Based on the weight part, (ii) 25 to 75 parts by weight of an epoxy resin having three or more epoxy groups in one molecule, (iii) 15 to 35 percent copolymerized acrylonitrile containing a carboxyl group at the end. diene rubber 75
~130 parts by weight, (iv) a latent curing agent having active hydrogen, with an equivalent ratio of epoxy group/(carboxyl group + active hydrogen) of 1/1 to 1
This is a flexible printed circuit board having an adhesive layer having a compounding amount in a range of 10.5.

In the present invention, epoxy resins having two epoxy groups in one molecule and having a number average molecular weight of 1,500 to 4,000 include bisphenol A type and bisphenol F type epoxy resins, specifically, for example, Epon 1004.1007.
1009 (manufactured by Shell Kagaku ■, trade name) and the like.

When the number average molecular weight is less than 1500, the heat-resistant type is inferior.

Moreover, when the molecular weight is greater than 4000, the adhesive strength decreases.

In the present invention, examples of epoxy resins having three or more epoxy groups in one molecule include glycidylamine epoxy resins, novolac epoxy resins, 0-cresol novolak epoxy resins, etc. From this point of view, glycidylamine-based epoxy resins are preferable.

Examples of the glycidylamine-based epoxy resin include tetraglycidyldiaminodiphenylmethane, triglycidyl-para-aminophenol, triglycidyl-meta-aminophenol, tetraglycidylmethaxylene diamine, and tetraglycidylbisaminomethylcyclohexane.

When the blending ratio is less than 25 parts by weight, heat resistance is poor.

Moreover, when the amount is more than 75 parts by weight, flexibility decreases.

In the present invention, the copolymerization amount of acrylonitrile is 15 to
Butadiene is generally used as the rubber component of diene rubber having carboxyl groups at both ends, which is 35% by weight. When the copolymerized amount of acrylonitrile is less than 15% by weight, adhesive strength and heat resistance are reduced. When the copolymerized amount of acrylonitrile is more than 35% by weight, flexibility decreases.

As a specific example, for example, Hiker (TON-130
0X13, CTBN-1300X8, CTBN-
1300X9 (USA, 8F+ Goodrich Co., Ltd.
(manufactured by Nippon Zeon Co., Ltd.) (trade name) Nipol 1072 (trade name, manufactured by Nihon Zeon Co., Ltd.). When the diene rubber is less than 75 parts by weight, the adhesive strength decreases. Moreover, when the amount is more than 130 parts by weight, the heat resistance is poor.

In the present invention, as a latent curing agent having active hydrogen,
For example, dicyandiamide, adipic acid dihydrazide,
dimer acid dihydrazide, isophthalic acid dihydrazide,
Examples include organic acid hydrazides such as cepatic acid dihydrazide, and one or two selected from the group consisting of these.
More than one species is used.

In the present invention, the blending equivalent ratio of carboxyl group to active hydrogen to epoxy group is in the range of 1/1 to 110.5 from the viewpoint of adhesion, heat resistance, and flexibility, and the amount of the latent hardening agent is is selected so that the active hydrogen satisfies this range.

When the equivalence ratio is less than 1, adhesive strength and flexibility decrease. When the equivalence ratio is greater than 2, heat resistance decreases.

The adhesive in the present invention has heat resistance, adhesive properties,
Although it has excellent flexibility, additives, inorganic fillers, etc. commonly used in adhesives can be mixed and used within the range that does not interfere with the curing of the present invention. Further, the adhesive of the present invention is generally used after being dissolved in a solvent.

The solvent used is not particularly limited as long as it dissolves epoxy, such as acetone, methyl ethyl ketone, xylene, toluene, butanol, and cellosolve acetate.

Copper, aluminum, or alloy foils thereof are generally used as the metal foil for the printed circuit board of the present invention.

A method for manufacturing a flexible printed circuit board using the above adhesive is, for example, by applying the adhesive to a polyether sulfone film (or gold rr4Fm) using a coating dryer to a thickness of 20±10μ, Room temperature ~120
Dry at a temperature range of 1 minute to 60 minutes. A flexible printed circuit board is made by overlapping metal foil on both sides of the adhesive-coated polyether sulfone film (or metal TR3) and using a heat press in the same manner as a normal board.

The pressing conditions are preferably 40°C to 150°C and 1 minute to 180 minutes. Furthermore, after pressing, harden at room temperature to 15
It is carried out for 30 minutes to 24 hours at 0°C. It can be easily manufactured using existing equipment without using such special equipment, and the present invention does not limit these conditions in any way.

〔Example〕

The present invention will be explained in more detail with reference to Examples below. In Examples and Comparative Examples, "part" or "%J" means parts by weight and % by weight, respectively.

[Examples and comparative examples]

Adjust the adhesive according to the formulation example in Table 1, and the thickness is 25 μm.
The thickness of the polyether sulfone film after drying is 1
After applying the adhesive to a thickness of 5μ to 20μ and drying it in an oven at 100°C for 5 minutes, apply a layer of 3μ to the adhesive-applied surface.
A 5μ copper foil is rolled at a temperature of 150℃ and a speed of 0.5.
The laminated product was laminated at a pressure of 5 kg/aJ at a pressure of 5 kg/aJ, and then cured in an open environment at 150° C. for 4 hours to obtain a flexible printed circuit board.

When preparing the adhesive, the amount of dicyandiamide, which is a powder raw material, is used! I went with three rolls.

Table 2 shows the performance evaluation results of the obtained copper clad board.

The symbols of the raw materials in Table 1 are as follows.

^: Made of oil-based shell epoxy ■Product name: Ebiko HO07 (
Molecule 12900) was dissolved in a mixed solvent of Kijirol/Cellosolve Acetate/Butanol-40/4G/2G with a solid content of 50% Press B: Same as Epicor) 1004 (molecular weight 1600)
Press C with a solid content of 50% by dissolving it in the above mixed solvent: Press C with a solid content of 50% by dissolving Epicote 100I (molecule 1900) in the above mixed solvent in the same way as A: Tetraglycidyl diaminodiphenylmethane E: Tetraglycidyldiaminodiphenylmethane Syzymeta-xylylenediamine

Claims (1)

[Scope of Claims] In a flexible printed circuit board comprising a polyether sulfone film and metal foil, (i) 100 parts by weight of an epoxy resin having two epoxy groups in one molecule and having a number average molecular weight of 1,500 to 4,000; (ii) 25 to 75 parts by weight of an epoxy resin having three or more epoxy groups in one molecule; (iii) diene rubber 75 containing carboxyl groups at the terminals copolymerized with 15 to 35% by weight of acrylonitrile; ~
130 parts by weight, (iv) a latent curing agent having active hydrogen, is blended so that the equivalent ratio of epoxy group/(carboxyl group + active hydrogen) is in the range of 1/1 to 1/0.5. A flexible printed circuit board having an adhesive layer.