JPH0689771A - Metal part with flexible printed wiring board and manufacture of metal part shape - Google Patents

Abstract

PURPOSE:To manufacture metal parts economically by subjecting each metal part to printed wiring while a compound layer of aromatic polyamide-imide resin soluble in organic solvent is used as a base film/adhesive layer in the condition that the metal part is equipped at least partially with flexibility. CONSTITUTION:A solution of aromatic polyamide-imide resin is applied to a certain place of a metal part 1 and dried to form a heat resistant insulative resin layer 2. A copper foil 3 is placed on this resin layer 2 half dried to a degree equipped with adhesiveness and attached fast by heating and pressurizing. On the copper foil 3, wiring patterns 4 are formed using a pattern resist, and after etching, the resist is exfoliated to produce the patterns. An overcoat layer 5 is provided in the necessary places on the printed wirings, and a rust-proof film 6 is applied to the exposed wiring parts. A specified portion of the metal part is removed to equip the printed wiring board partially with flexibility, and a part 9 is furnished where the layer 2 is used as the base layer having flexibility. Thereby the part can be constructed light and thin.

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 printed wiring is directly provided through an aromatic polyamideimide resin layer in a state where at least a part of the metal molded article retains flexibility. The present invention relates to a product and a manufacturing method thereof.

[0002]

2. Description of the Related Art In response to the demand for higher density and lower cost of electronic and electric devices, 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,
There is a metal part with FPC in which a part of the metal molded product is removed and the FPC is laminated in that part while maintaining the original flexibility. In order to manufacture such parts, molded circuit parts manufactured by injection molding engineering plastics have been developed.

However, in the case of metal parts, there is no suitable molding technique such as injection molding in plastics, and a technique for simply manufacturing a component integrated with an FPC such as a molded circuit component of plastics is now available. However, it has not been realized. That is, in order to make a metal part having a form close to that, a printed wiring 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 way to manufacture it was to fix it to the required place with an adhesive or bolts.

According to this conventional method, after a metal molded product is processed into a required shape, it is further subjected to post-processing such as punching, chamfering, punching for attaching a printed wiring board, application of an adhesive, and bolt tightening. In addition to the need for a fixing process, there is a problem in that special measures and labor are required for alignment and the like, and there is a limit to the total thickness due to the base material and adhesive that compose the printed wiring board. However, there is a problem that it is difficult to make the device thinner and lighter.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems which a conventional metal part with a flexible printed wiring board has, and does not require fixing work such as adhesion or bolting of a printed wiring board. , A flexible printed wiring that can be manufactured extremely simply and economically, and partially overcomes the drawbacks of heat resistance and moisture resistance derived from the substrate or adhesive of the printed wiring board and the limitations of thinning and weight reduction. An object is to provide a metal molded product with a plate.

[0006]

Therefore, the present inventor has found that a resin having heat resistance and humidity resistance, particularly dimensional stability under heat and humidity and flexibility, good workability and adhesiveness, and an insulating property is required. If it is used as an insulating base film layer / adhesive layer, a circuit can be formed directly on the metal molded product, and if an etching resist is formed on the metal molded product to etch the necessary parts of the metal molded product, the desired partial flexibility can be obtained. Based on the idea that a printed circuit part having a portion can be obtained, as a result of diligently searching for such a resin, by using a specific organic solvent-soluble aromatic polyamide-imide resin, the problems of the present invention are solved at once. The inventors have found out what can be done and have completed the present invention.

That is, according to the present invention, an FPC is directly provided on a metal molded article through a layer composed of an organic solvent-soluble aromatic polyamideimide resin composition, and a part of the FPC is exposed, and the FPC is flexible there. Is a metal molded article with a printed wiring board that retains its properties, and in order to obtain it, after applying an aromatic polyamideimide resin composition dissolved in an organic solvent to a predetermined position of the metal molded article, The printed wiring is directly formed on the FPC by a subtractive method or an additive method, and then at least a part of the metal molded product including a portion below the necessary portion is etched by etching in order to make the necessary portion of the FPC flexible. Disclosed is a method for producing a metal molded article with a printed wiring board, which is characterized by removing the metal molded article.

The present invention will be described in detail below. The organic polar solvent-soluble aromatic polyamideimide resin used in the present invention has the general formula

[0009]

[Chemical 1] However, R is a hydrogen atom, a halogen atom, or an alkyl group, and X represents an oxygen atom, a sulfur atom, or a sulfonyl group. Among these, an aromatic polyamideimide resin in which R is a hydrogen atom and X is an oxygen atom, for example, 4,4′-diaminodiphenyl ether as an aromatic diamine component is preferable.

A reduced viscosity of 0.8 to 3.5, preferably 0.1 to 3.0 is 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. Further, if the reduced viscosity is too high, the compatibility decreases, which is not preferable. In addition, the above-mentioned resin has a high thermal conductivity filler such as beryllia (BeO), magnesia (MgO), boron nitride (BN), and alumina (Al ₂ O).
₃ ), silicon carbide (SiC), silicon nitride (Si
Even better results are obtained by adding 1 to 3% by volume of ₃ N ₄ ), mica and mixtures thereof.

The above-mentioned aromatic polyamideimide resin used in the present invention can be produced by a known method, for example, by reacting an aromatic diamine and trimellitic anhydride chloride in an organic polar solvent, or by reacting an aromatic diisocyanate and trimellitic anhydride with an organic compound. It can be produced by reacting in a polar solvent. Further, since SOXR (registered trademark) marketed by Nippon Koshigyo Kogyo Co., Ltd. is the above-mentioned suitable aromatic polyamide-imide resin, it can be used.

As the aromatic diamine used in the present invention, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone,
4,4'-diaminodiphenylmethane can be mentioned. Of these, 4,4'-diaminodiphenyl ether is particularly preferable from the viewpoint of moisture resistance.

As the organic solvent for the aromatic polyamide-imide resin, N, N-dimethylformamide, N, N-
Dimethylacetamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, hexamethylphosphoramide,
Examples thereof include halogenated cresols or mixed solvents thereof, or mixed solvents of these and other conventional solvents. Of these, N, N-dimethylacetamide and N-methyl-2-pyrrolidone are particularly preferable.

The metal molded product to which the present invention is applied is mainly used as a part of electronic / electrical equipment, and the material thereof is a metal such as aluminum, iron, stainless steel, silicon steel or the like.

To give some specific examples, lead parts, connectors, motor switches, and other parts with reinforcing plates, parts that require heat radiation, electromagnetic wave shielding, and electrical characteristics, or various high-density mounting parts Etc.
Especially, the floppy disk drive (FD
It is preferably used for a head component for D) and a rotation control circuit component for a motor.

The following method may be used for producing the metal molded product with a printed wiring according to the present invention. FIG. 1 schematically shows the steps of the manufacturing method of the present invention. That is, (1) The above-mentioned aromatic polyamide-imide resin solution is applied to a predetermined portion of the metal molded product 1, for example, manufactured by Nippon Koshigami Kogyo.
SOXR (registered trademark) is applied and dried using a far infrared dryer or the like to form the 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 can be used. Among them, the screen printing method is simple and preferable. When the copper foil is laminated, it is desirable to dry after coating at 80 to 150 ° C., preferably about 100 ° C. for several minutes, and when a conductive paste is printed on it and used, It is advisable to dry completely, i.e. at 150 to 250 [deg.] C., preferably about 200 [deg.] C. for a few minutes.

(2) Next, a printed wiring is formed on the heat resistant insulating resin layer 2 obtained in (1) by either of the following two methods. Subtractive method (a) The above resin layer 2 semi-dried to the extent that it has adhesiveness
The copper foil 3 is placed on the above, and heated and pressed (laminating 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, the resist is peeled off after etching. (C) Further, an overcoat layer 5 is provided on a required portion of the printed wiring by screen printing or film laminating, and a rust preventive film (flux, solder coat, plating, etc.) 6 is applied to the exposed wiring portion.

Conductive paste printing method (a) Conductive paste 7 is formed on the completely dried resin layer.
Is screen-printed to form a predetermined wiring circuit. (B) The overcoat layer 5 is provided at a required portion of the wiring circuit by screen printing or film lamination,
Further, 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 maintain flexibility in a portion of the printed wiring board. In the metal molded product 1 supporting the printed wiring board formed in (2), a portion of the metal molded product including a portion below the FPC portion for which flexibility is to be retained is removed by etching, A portion 9 in which the heat resistant insulating layer 2 is a flexible base material layer is provided.

[0022]

The present invention will be described in the following examples. Example 1 A backing plate of a φ25.0 mm circular motor rotation control component is punched out from a silicon steel plate having a thickness of 0.5 mm. On top of the silicon steel plate, SOXR made by Nippon Koshigami Co., Ltd.
(Solvent-soluble aromatic polyamide-imide resin: registered trademark)
Of the solution of No. 2 by screen printing with a thickness of about 20 μm, φ24.0
After being applied in a shape in which a part of protrusions are provided in a circle of mm, it is dried by a far infrared dryer or the like at 100 ° C. for 5 minutes to provide an insulating layer in a semi-dried state.

A commercially available copper foil (35 μm) is placed on it,
20 ~ 30kg / at 180 ℃ for 20 minutes 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 (dry film type etching resist manufactured by Hitachi Chemical Co., Ltd.) through an exposure to development process.

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 to be peeled off. Next, this is heated stepwise, and finally 200 ° C.
After heating for about 5 minutes, main drying is performed. Furthermore, the above S
An OXR solution is used to screen print to provide an overcoat at the required locations, and then the exposed wiring portions are plated.

Next, the silicon steel portion laminated on the portion of the printed wiring portion requiring flexibility is removed through exposure, development and etching steps using a commercially available etching resist (dry film). As a result, 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, a copper foil having a thickness of 35 μm and a polyimide base film having a thickness of 25 μm were used to form the same printed wiring on the copper clad laminate by the same subtractive method as above.
Table 1 shows the performance of a conventional component in which a printed wiring board manufactured by similarly performing overcoating and soldering was adhered to a silicon steel plate of the same rotation control component for a motor as described above by an acrylic adhesive. From the results of Table 1, it can be seen that the printed wiring part of the present invention is superior to the conventional one in terms of inter-line insulation, solder heat resistance, adhesion, and thickness.

Example 2 In the same manner as in Example 1, a silicon steel plate backing plate coated with the same SOXR as in Example 1 is prepared. Unlike the case of Example 1, the drying of SOXR was completely dried by a far infrared dryer at 200 ° C. for 5 minutes to form an insulating resin layer. A copper paste made of Tatsuta Electric Wire is screen-printed thereon to form a predetermined wiring pattern. Use a far-infrared dryer at 150 ℃
Dry for 5 minutes.

Next, an overcoat is provided at a required portion by screen printing using an epoxy solder resist. Next, rust preventive flux is applied to the exposed wiring portion. Next, in the same manner as in Example 1, the silicon steel portion laminated on the portion of the printed wiring that requires flexibility is removed by the same method using the same resist as in Example 1. A control part for a motor with a flexible printed wiring board having partial flexibility can be obtained. The performance of this product was superior to that of the conventional product as in Example 1.

[0029]

[Table 1]

[0030]

The metal molded product with a flexible printed wiring board which retains flexibility as a part of the present invention is such that the printed wiring board, which was conventionally required to obtain it, is fixed to the molded product by adhesion or bolting. Since it does not require any work and does not require post-processing for metal moldings or printed wiring boards or dies for them, it has the effect that it can be manufactured extremely simply and economically. It has the effects of reducing heat resistance and moisture resistance, and overcoming the limitations of thinning and weight reduction.

[Brief description of drawings]

FIG. 1 is a sectional view showing an outline of steps of a manufacturing method of the present invention.

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

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

FIG. 4 is a rear view and a cross-sectional view of the metal part with FPC of FIG.

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

[Explanation 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)

[Claims] 1. A printed wiring having an organic solvent-soluble aromatic polyamide-imide resin composition layer as a base film / adhesive layer is directly provided on a metal molded product while at least a portion of the metal molded product maintains flexibility. Metal molded product with flexible printed wiring board. 2. After applying an aromatic polyamideimide resin composition dissolved in an organic solvent to a predetermined portion of a metal molded article, and then directly forming a printed wiring thereon by a subtractive method or an additive method. , In order to give flexibility to necessary parts of the flexible printed wiring board,
A method for producing a metal molded article with a flexible printed wiring board having partial flexibility, characterized in that a part of the metal molded article including at least a portion below the necessary portion is removed by etching. 3. The flexible printing having partial flexibility according to claim 2, wherein an overcoat is provided at a predetermined portion of the printed wiring board, and an anticorrosive film is provided on an exposed wiring portion. Manufacturing method of metal molded product with wiring board.