JP2734904B2 - Metal molded product with flexible printed wiring board and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal molding with a flexible printed wiring board in which a printed wiring is directly provided via an aromatic polyamide-imide resin layer while at least a part of the metal molded article is kept flexible. The present invention relates to a product and a method of manufacturing the same.

[0002]

2. Description of the Related Art With the demand for higher density and lower cost of electronic and electric equipment, metal parts in which a flexible printed wiring board (hereinafter abbreviated as FPC) is laminated on a metal molded product have been developed and used. ing. As one of them,
A part of the metal molded product is removed, and there is a metal part with an FPC in which the FPC is laminated while maintaining its original flexibility. In order to manufacture such components, molded circuit components manufactured by injection molding engineering plastics or the like have been developed.

However, there is no suitable molding technique for metal parts such as injection molding of plastics, and a technique for easily manufacturing a part integrated with an FPC, such as a molded circuit part of plastics, has been developed today. However, it has not been realized. In other words, in order to make a metal part similar to that, a printed circuit board obtained by forming a printed circuit on a copper-clad laminate for a printed circuit by an ordinary method is separately molded into a desired shape. The only available method was to fix it to the necessary place with an adhesive or bolting.

According to this conventional method, after a metal molded product is processed into a required shape, it is subjected to post-processing such as drilling, chamfering, and punching for mounting a printed wiring board, application of an adhesive, and bolting. In addition to the need for a fixing step, there is a problem that special measures and labor are required for positioning and the like, and the total thickness is limited due to the base material and the adhesive constituting the printed wiring board. However, there is a problem that it is difficult to reduce the thickness and weight of the device.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems which the conventional partially flexible metal parts with a printed wiring board have, and eliminates the fixing work such as bonding or bolting of a printed wiring board. Flexible printed wiring that can be manufactured extremely simply and economically and partially overcomes the drawbacks of heat and moisture resistance and the limitations of thinning and weight reduction due to the substrate or adhesive of the printed wiring board. It is an object to provide a metal molded product with a plate.

[0006]

Therefore, the present inventor has proposed a resin having heat resistance and moisture resistance, particularly dimensional stability and flexibility at the time of heat resistance and humidity, good workability and adhesiveness, and insulating properties. If it is used as an insulating base film layer and an adhesive layer, a circuit can be formed directly on the metal molded product, and if an etching resist is formed on it and the required parts of the metal molded product are etched, the desired partly flexible Based on the idea that a component with a printed circuit having a portion can be obtained, as a result of eagerly searching for such a resin, the problem of the present invention can be solved all at once by using a specific organic solvent-soluble aromatic polyamideimide resin. We have found that we can do this and completed the present invention.

That is, the present invention provides the following to the metal forming portions article
Directly through a layer comprising an organic solvent-soluble aromatic polyamide-imide resin composition having a repeating unit of the formula
A PC is provided, and a part of the FPC is exposed;
There is electronic and electric with printed wiring board that maintains flexibility
A metal molded part article equipment, also for obtaining it, after the above <br/> aromatic polyamideimide resin composition is dissolved in an organic solvent was applied to a predetermined portion of the metal molded part article, the It allowed formed directly printed wiring by a subtractive method or additive method above, followed order to give flexibility to the necessary portions of the FPC, a part of the metal molded part article comprising a portion below the at least a necessary part there is provided a printed wiring Backed manufacturing method for <br/> metal molded part article electronic and electrical equipment, and removing by etching.

Hereinafter, the present invention will be described in detail. The organic polar solvent-soluble aromatic polyamide-imide resin used in the present invention is a repeating unit

[0009]

Embedded image However, R represents a hydrogen atom, a halogen atom, or an alkyl group . Incidentally, preferably among these is an aromatic polyamideimide resin R is to be <br/> for example 4,4'-diaminodiphenyl ether with an aromatic diamine component of hydrogen atom.

[0010] Those having a reduced viscosity of 0.8 to 3.5, preferably 0.1 to 3.0 are used. If the reduced viscosity is too low, there is a problem in heat resistance and flexibility, and cracks tend to occur after film formation. On the other hand, if the reduced viscosity is too high, the compatibility is undesirably reduced. In addition, a high thermal conductive filler such as beryllia (BeO), magnesia (MgO), boron nitride (BN), and alumina (Al ₂ O)
₃ ), silicon carbide (SiC), silicon nitride (Si
₃ N _4), mica and better results when mixtures thereof are added 1-3% by volume is obtained.

The aromatic polyamide-imide resin used in the present invention can be prepared by a known method, for example, by reacting an aromatic diamine with trimellitic anhydride chloride in an organic polar solvent or by converting an aromatic diisocyanate and trimellitic anhydride into an organic solvent. It can be produced by reacting in a polar solvent. Further, SOXR (registered trademark) commercially available from Nippon Kogyo Paper Industries Co., Ltd. is a suitable aromatic polyamide-imide resin described above, and thus can be used.

As the aromatic diamine used in the present invention, 4,4'-diaminodiphenylether, 4,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 4,4'-diaminobenzophenone,
4,4'-diaminodiphenylmethane can be mentioned. Of these, 4,4′-diaminodiphenyl ether is particularly preferred from the viewpoint of moisture resistance.

As the organic solvent for the aromatic polyamideimide resin, N, N-dimethylformamide, N, N-
Dimethylacetamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, hexamethylphosphoramide,
Halogenated cresol, a mixed solvent thereof, or a mixed solvent thereof with another conventional solvent can be used. Of these, N, N-dimethylacetamide and N-methyl-2-pyrrolidone are particularly preferred.

The metal molded product to which the present invention is applied is mainly used as a part of an electronic / electric device, and its material is a metal, for example, aluminum, iron, stainless steel, silicon steel or the like.

Some specific examples are given below. Components having a reinforcing plate such as lead components, connectors, motor switches, etc., components requiring heat radiation, electromagnetic wave shielding and electrical characteristics, or various high-density mounting components And the like.
Especially, floppy disk drive (FD)
It is suitably used for D) head parts and motor rotation control circuit parts.

The following method may be used to produce the metal molded product with printed wiring of the present invention. FIG. 1 schematically shows the steps of the manufacturing method of the present invention. That is, (1) The above-mentioned aromatic polyamideimide resin solution, for example, manufactured by Nippon Kogyo Kogyo Co., Ltd.
SOXR (registered trademark) is applied and dried using a far-infrared dryer or the like to provide a heat-resistant insulating resin layer 2.

As a coating method, a known screen printing method, blade coaster method, metal mask printing method, roll coater method, or the like is used. Among them, the screen printing method is simple and preferred. In addition, drying after coating is preferably performed at 80 to 150 ° C., preferably about 100 ° C. for several minutes when laminating a copper foil, and more preferably when a conductive paste is printed thereon and used. Drying is complete, i.e. at 150-250C, preferably at about 200C, for several minutes.

(2) Next, a printed wiring is formed on the heat-resistant insulating resin layer 2 obtained in (1) by one of the following two methods. Subtractive method (A) The above resin layer 2 which is semi-dried to the extent that it has adhesiveness
The copper foil 3 is placed on the sheet, and is heated and pressed (lamination press) to be laminated.

(B) A printed wiring (pattern) is formed by a known subtractive (etching) method in which a wiring pattern 4 is formed on the copper foil using a pattern resist, and the resist is peeled off after etching. (C) Further, an overcoat layer 5 is provided by screen printing or lamination of a film at a place where a printed wiring is required, and a rust preventive film (flux, solder coating, plating, etc.) 6 is applied to the exposed wiring part.

Conductive paste printing method (a) Conductive paste 7 is placed on the completely dried resin layer.
Is screen printed to form a predetermined wiring circuit. (B) The overcoat layer 5 is provided at a necessary portion of the wiring circuit by screen printing or film lamination,
In addition, a rust preventive film (flux, solder coat, plating, etc.) 6 is applied to the exposed wiring portion.

(3) A predetermined portion of the metal molded product is removed in order to keep a part of the printed wiring board flexible. In the metal molded product 1 supporting the printed wiring board formed in (2), a portion of the metal molded product including a portion under the FPC portion to be kept flexible is removed by etching, A portion 9 is provided in which the heat-resistant insulating layer 2 is used as a flexible base material layer.

[0022]

The present invention will be described below with reference to examples. Example 1 A circular backing plate of a rotation control component for a motor having a diameter of 25.0 mm was punched out from a silicon steel plate having a thickness of 0.5 mm to produce the same. SOXR made by Nippon Advanced Paper Industry on the silicon steel plate
(Solvent-soluble aromatic polyamide-imide resin: registered trademark)
Solution was screen-printed to a thickness of about 20 μm and φ24.0.
After applying in a shape having a partly protruding portion in a circular shape of mm, it is dried at 100 ° C. for 5 minutes with a far-infrared drier or the like to provide a semi-dry insulating layer.

A commercially available copper foil (35 μm) is placed thereon,
20-30 kg / 20 minutes at 180 ° C using a heat press
Laminate under pressure of cm ² . A predetermined wiring pattern is formed on the copper foil by using a commercially available resist (a dry film etching resist manufactured by Hitachi Chemical Co., Ltd.) through an exposure-development process to form a resist pattern.

Next, this is etched with an alkaline etching solution at 50 to 55 ° C. for 1 to 2 minutes, and then the pattern resist is treated with a methylene chloride solution for 1 to 2 minutes and peeled off. Next, this is heated step by step, finally at 200 ° C.
For about 5 minutes to perform main drying. Further, the above S
An overcoat is provided on a required portion by screen printing using an OXR solution, and then the exposed wiring portion is plated.

Next, the silicon steel portion laminated on the portion of the printed wiring portion that requires flexibility is removed through exposure-development-etching steps using a commercially available etching resist (dry film). Thereby, a control part for a motor with a flexible printed wiring board having flexibility in a target portion can be obtained.

As a comparative example, the same printed wiring was formed on a copper-clad laminate having a copper foil of 35 μm and a polyimide base film of 25 μm by the same subtractive method as described above.
Table 1 shows the performance of a conventional component in which a printed wiring board manufactured by performing the same overcoating and soldering to a silicon steel plate of the same rotation control component for a motor as described above with an acrylic adhesive. From the results shown in Table 1, it can be seen that the printed wiring component according to the present invention is superior to the conventional component in terms of line insulation, solder heat resistance, adhesion, and thickness.

Example 2 In the same manner as in Example 1, a silicon steel sheet backing plate coated with the same SOXR as in Example 1 is produced. The drying of SOXR is different from that of Example 1 and completely dried at 200 ° C. for 5 minutes using a far-infrared dryer to form an insulating resin layer. Then, a predetermined wiring pattern is formed by screen-printing a copper paste made of a stub wire. This is 150 ° C in a far-infrared dryer,
Dry for 5 minutes.

Next, an overcoat is provided on a necessary portion by screen printing using an epoxy solder resist. Next, a rust-proof flux is applied to the exposed wiring portion. Next, in the same manner as in the first embodiment, the portion of the silicon steel laminated on the portion requiring the flexibility of the printed wiring is removed by the same method using the same resist as in the first embodiment. As a result, a control part for a motor with a flexible printed wiring board having partial flexibility can be obtained. Its performance was superior to that of the conventional product as in Example 1.

[0029]

[Table 1]

[0030]

According to the present invention, a metal molded product with a flexible printed wiring board, which retains flexibility in a part of the present invention, is such that a printed wiring board, which was conventionally required for obtaining the same, is fixed to the molded product by bonding or bolting. No work is required, and there is no need for post-processing of metal molded bodies or printed wiring boards, and no molds for them. Therefore, it has the effect of being extremely simple and economical to manufacture. This has the effect of overcoming the limitations of heat and moisture resistance and the limitations of thinning and weight reduction.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing the steps of the manufacturing method of the present invention.

FIG. 2 is a cross-sectional view schematically showing the steps of the manufacturing method of the present invention (continuation of FIG. 1).

FIG. 3 is a plan view of the FPC-equipped component according to the first embodiment of the present invention.

4 is a rear view and a sectional view of the metal part with an FPC of FIG. 3;

FIG. 5 is a perspective view of another example of the metal part with FPC of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Part of metal molded product 2 Heat resistant insulating resin (aromatic polyamideimide) layer 3 Copper foil 4 Pattern resist 5 Overcoat 6 Solder 7 Conductive paste 8 Etching resist 9 Flexible part

Claims (3)

(57) [Claims] With at least partially holding the flexible 1. A metal formed part article, repeating units embedded image (Wherein R is a hydrogen atom, a halogen atom, or an alkyl group
With a flexible printed wiring board on which printed wiring is directly provided using an organic solvent-soluble aromatic polyamideimide resin composition layer having
For electronic and electrical equipment metal forming part article. Wherein repeating units embedded image which is dissolved in an organic solvent at a predetermined point metal molded part article (Wherein R is a hydrogen atom, a halogen atom, or an alkyl group
Is applied, and after a printed wiring is directly formed thereon by a subtractive method or an additive method, a necessary portion of the flexible printed wiring board has flexibility. thereby Therefore, a flexible printed wiring fitted with electrons having a portion flexible and removing a portion of the metal molded part comprising a portion below the at least a necessary portion by etching
・ Method of manufacturing metal molded parts for electrical equipment . 3. The partially flexible printing according to claim 2, wherein an overcoat is provided on a predetermined portion of the printed wiring board and a rust-preventive film is provided on an exposed wiring portion. wiring Backed method for manufacturing electronic and electrical equipment metal formed part article.