JPH06140746A - Method for printed-circuit transfer molding - Google Patents

Abstract

PURPOSE:To avoid the melting down.expansion and contraction of a transfer film due to the molding heat and pressure during the transfer molding step. CONSTITUTION:A transfer film base material 1 is made of a metal such as copper, etc. Next, this film A is Printed with a circuit pattern 2 using a conductive paste and after the arrangement of this transfer film A with the circuit pattern 2 turning to the surface side in a press or injection metallic mold B, this mold B is filled up with a molding resin (a) to transfer the circuit pattern 2 on the transfer film A to the surface of the molding resin (a) simultaneously with the molding step. At this time, even if a high temperature, high injection pressure applicable material such as an engineering plastic, etc., is used for the molding resin (a), the film 1 made of the metal such as copper, etc., will not be melted down.expanded or contracted by the heat and pressure. Accordinly the circuit pattern 2 can be precisely transferred.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transferring an electronic circuit (circuit pattern) formed on a transfer film onto a molded body simultaneously with molding.

[0002]

2. Description of the Related Art A transfer printed circuit forms a circuit pattern by printing various metal powder pastes on a base film (transfer film) by a conventional method such as a screen printing method, and forms this circuit on the inner surface of a molding die. The pattern is arranged on the front side, and the circuit pattern on the film is transferred onto the surface of the molded product at the same time when the substrate is molded.

Injection molding and press molding are mainly performed for the substrate molding. In the former method, a resin composition is injected and filled in a mold, and simultaneously with the injection molding, a circuit pattern is formed on the surface of the molded product. Transfer to. In the latter, after molding the resin composition in a mold, the mold is opened, a transfer film is placed on the upper surface of the molded product, and the mold is closed again and heated and pressed. , The circuit pattern is transferred onto the upper surface of the molded product.

[0004]

In the above conventional transfer molding method, a plastic film, particularly a polyethylene terephthalate (PET) film is used as the transfer film. This plastic film is relatively sensitive to heat and pressure.

On the other hand, engineering plastics (hereinafter referred to as engineering plastics) or super engineering plastics are used as molding resins in view of mechanical strength and the like. This engineering plastic has high molding temperature and molding pressure (injection pressure).

Therefore, when the transfer printed circuit is manufactured on the upper surface of the molded product as described above, if the plastic film is used as the transfer film and the engineering plastic is used as the molding resin, the film may melt due to the molding temperature and the molding pressure of the engineering plastic. There is a problem that expansion and contraction prevent accurate transfer of the circuit pattern.

Therefore, an object of the present invention is to make it possible to accurately transfer a circuit pattern without expansion and contraction of the transfer film even if engineering plastic is used as the molding resin.

[0008]

In order to solve the above problems, according to the present invention, in the transfer molding method for a printed circuit in the above injection molding or press molding, the transfer film is made of metal. .

As the transfer film material, iron, copper, nickel, stainless steel, aluminum and the like can be used, and the film includes all materials such as sheets and foils which serve as transfer base materials. Further, the film may be plated with a metal such as chrome.

The circuit pattern is Au, Ag, Cu, N
It is formed by using a conductive paste such as i, Pd, Al, and C by an appropriate means such as a screen printing method, a gravure printing method, or an offset printing method.

As the molding resin, polyamide, acrylonitrile butadiene styrene copolymer, polycarbonate, polyphenylene sulfide, polyacetal, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyarylate, polysulfone, polyether sulfone, polyether imide, polyether. Ether ketone, polyamide imide,
Thermoplastic resins such as liquid crystal polymers and their polymer alloy resins can be used.

[0012]

In the transfer molding method thus constructed, since the transfer film is made of metal, even if engineering plastic or super engineering plastic is used as the molding resin, the transfer film does not melt or expand or contract due to its heat and pressure. Therefore, accurate transfer of the circuit pattern is performed.

[0013]

Example 1 As shown in FIG. 1, length × width: 165 × 15
A circuit pattern 2 is formed by screen printing using a conductive copper paste on a copper film 1 having a thickness of 0 mm and a thickness of 16.5 μm.
Was printed to prepare a transfer film A.

Next, as shown in FIG. 2, the transfer film A is placed at a predetermined position in the injection molding die B, the die B is closed, and the molten polyamide a is subjected to the following conditions. Injection molded in.

Cylinder temperature 240 ° C. in the rear part, 260 ° C. in the middle part, 280 ° C. in the front part ・ Nozzle temperature 280 ° C. ・ Mold temperature 75 ° C. ・ Injection pressure 1000 to 1600 kg / cm ²
.

Next, the molded body P is taken out from the mold B, the copper film 1 is peeled off, and the circuit pattern 2 is formed on the surface.
Thus, a molded body P to which was transferred was obtained. The circuit pattern 2 was transferred to a predetermined position on the surface of the molded body P as shown in FIG.

As a comparative example, a thickness 50 after the release treatment is applied.
Using a PET film of μm as a transfer film, injection molding was performed under the same conditions as in the example, and the molded product was taken out from the mold B. The PET film was stretched and the circuit pattern was transferred to a predetermined position. There wasn't.

[0018]

Example 2 As shown in FIG. 4, a ferro-type chrome plate 13 was laid on the upper surface of a lower pressure plate 11 of a press molding machine, and a metal frame 12 having an inner size of 185 × 170 mm and a thickness of 2 mm was placed and fixed thereon.

Next, the metal frame 12 is filled with the molding resin shown in Table 1, and a ferro-type chrome plate 14 is placed on the resin.
The upper pressure plate 10 is lowered and heated / pressurized to obtain a preformed plate b having a smooth surface.

Then, as shown in FIG. 5, the press is released to remove the ferro-type chrome plate 14, and the transfer film A prepared above is printed so that the printed surface of the circuit pattern 2 faces the preformed plate b side. By placing and pressing the copper film A under the molding conditions shown in Table 1, the copper film A was peeled off to obtain a molded body P in which the circuit pattern 2 was transferred to the surface of the molded plate b (resin plate a) as shown in FIG. The transferability and the adhesion of the molded product P are shown in Table 1, and in each example, the circuit pattern 2 was all transferred to a predetermined position.

As a comparative example, a thickness 50 after the release treatment is applied.
The results of press molding shown in Table 1 using a PET film of μm as a transfer film are shown in the same table. In each comparative example, the PET film was stretched and the circuit pattern was not transferred to a predetermined position. .

[0022]

[Table 1]

From the results of Table 1 and the like, it can be understood that the examples are superior to the comparative examples in terms of transfer accuracy and adhesion.

Although the present invention has been described only with respect to injection molding and press molding, the present invention can be adopted in vacuum molding or blow molding as long as a sufficient pressure contact force for transfer can be imparted. The transfer of the circuit pattern 2 is
By transferring to not only the printed circuit board but also the casing of various devices, an electric circuit can be formed on the inner surface of the casing and the like.

[0025]

Since the present invention is configured as described above, an accurate transfer circuit pattern can be obtained even when the printed circuit board is a molding resin such as engineering plastic having high heat and high pressure.

[Brief description of drawings]

FIG. 1 is a perspective view of a transfer film according to an embodiment.

FIG. 2 is a sectional view for explaining the operation of one embodiment.

FIG. 3 is a perspective view of a printed circuit board (molded body) according to an embodiment.

FIG. 4 is a perspective view showing the operation of another embodiment.

FIG. 5 is a sectional view for explaining the operation of the same embodiment.

[Explanation of symbols]

 1 Metallic Film (Copper Film) 2 Circuit Pattern 10 Upper Pressure Plate 11 Lower Pressure Plate 12 Metal Frames 13, 14 Ferrotype Chrome Plate A Transfer Film B Mold P Molded Body a Injection Molded Resin b Molded Product (Molded Plate)

Front page continuation (72) Inventor Kazunori Sugiyama 2-3-1 Iwata-cho, Higashi Osaka City Tatsuta Electric Wire Co., Ltd. (72) Inventor Shinichi Wakita 2-3-1 Iwata-cho, Higashi Osaka City Tatsuta Electric Wire Co., Ltd. In the company

Claims (2)

[Claims] 1. A circuit pattern is printed on a metal film with a conductive paste, and the film is placed on the inner surface of an injection molding die with the circuit pattern on the front side. Then, an injection molding resin is placed in the die. A transfer-molding method for a printed circuit, comprising injecting and transferring the circuit pattern on the film onto the surface of a resin molded product at the same time as the injection molding. 2. A metal for which a circuit pattern is printed by a conductive paste on the upper surface of the resin composition molded product after the resin composition is filled in a press molding mold for molding, and the mold is opened. A print characterized in that a transfer film is arranged with its circuit pattern on the upper surface of the molded product, the mold is closed again, and the circuit pattern on the transfer film is transferred to the upper surface of the molded product by heating and pressing. Circuit transfer molding method.