JPH0473686B2 - - Google Patents

Description

Detailed Description of the Invention [Field to which the invention pertains] The present invention relates to the molding of a main body case, cover, or intermediate part of an electrical device, etc., which is attached to a case using a resin material, and particularly relates to the molding of an electrical circuit component by soldering onto the surface of a molded product. The present invention relates to a molded product having a land portion of a circuit pattern to be attached, and a method for molding the molded product.

[Prior art to the invention]

Conventionally, as a means for electrically connecting circuit components forming an electric circuit, a printed circuit board with a circuit pattern wired thereon is provided, and an integrated circuit (IC, LSI), Tr. A circuit is constructed by soldering circuit components such as...
They were attached to covers, intermediate products, etc., and wired connectors were used to connect each circuit block. As electric circuits become more complex, the number of components in these printed circuit boards increases, increasing the degree of circuit integration, and requiring a reduction in the space for placing printed circuit boards within equipment. This caused problems such as contact with other circuit components or adhesion of conductors between patterns, resulting in circuit shorts. In order to solve these problems in the field of printed circuit board technology, as shown in Japanese Utility Model Publication No. 59-773,
A printed circuit board is covered with a protective film, and an opening is provided to expose a plurality of lands for fixing circuit components to the protective film, and both ends of the opening in at least one direction of the opening of the opening are provided. A printed circuit board characterized by being coated with a covering material so as to straddle the opening and overlap the protective film at both ends of the opening, or a flexible material such as synthetic resin as shown in Japanese Patent Publication No. 60-5240. an electrically conductive foil is formed on the surface of a flexible wiring board from an insulating film having a There is a flexible printed wiring board that is characterized by:

However, in recent years, with the development of resin molding technology and resin materials, conventional methods for forming circuits on the surface of resin molded products include providing concave lines on the molded product and applying partial electrolytic plating there;
There is a method in which a film with a circuit pattern formed thereon is inserted into a mold, and the circuit pattern is transferred from the film to the molded product at the same time as molding.

In addition, as a method of forming a conductive film on the surface of a resin molded product, a powdered resin composition containing a high concentration of conductive fine powder is applied into a mold by electrostatic coating, and then the resin molded product is molded. Method (Unexamined Japanese Patent Publication 1986-
111335).

However, the method of providing concave lines on the molded product cannot accommodate three-dimensional shapes, and furthermore, the process becomes complicated because the molded product is subjected to a plating process as a secondary process. Furthermore, the method using a film has limitations in its ability to handle deeply drawn shapes and three-dimensional shapes due to problems such as the film being torn or the wiring being cut. In the method disclosed in JP-A-61-111355, the ratio of conductive fine powder contained in the powdered resin composition is large, and the resin component is small, resulting in insufficient strength of the film, and the film may shift due to the pressure of the injected resin.
The drawback was that cracks occurred and the film lacked reliability as a conductive film.

[Problems to be solved by the invention]

The present invention solves the weak points in the strength of the circuit pattern portion produced by the circuit pattern forming method using plating or the circuit pattern transfer method described above, and further provides a molded product having a circuit pattern that is sufficiently satisfactory for current conduction as a circuit pattern. do.

Furthermore, the present invention provides a circuit pattern that allows electrical components such as integrated circuits to be mounted on molded products made of resin materials, such as the main body of an electronic desktop calculator (hereinafter referred to as a calculator), the main body of a camera, a cover, etc. We propose a molded article and a method for manufacturing the molded article.

Further, the present invention is a molded product in which only the land portion of the circuit pattern portion to which the circuit components are soldered is exposed on the surface of the molded product, and the routed portion of the circuit pattern portion is buried under the insulating resin material. The objective is to obtain a resin molded product in which the main body and circuit pattern are integrally molded.

[Means for achieving the aforementioned tasks]

In order to achieve the above-mentioned object, the present invention provides a mold for molding a molded article, for example, a body or a cover of a device on which other electrical parts such as the aforementioned calculator or camera are mounted. When molding a molded product using the mold, the circuit pattern is molded through the following steps.

First, the cavity surface of the mold is masked using a first mask that exposes a portion other than the land portion, and a composition containing an insulating material is applied to the exposed surface of the cavity surface.

Next, in order to form a circuit pattern portion of the conductive material, the circuit pattern portion is masked with a second mask having an opening, and a circuit pattern composition for forming the circuit pattern portion is applied from above the second mask. adhere to.

Following removal of the second mask, a molding resin material is injected into the cavity of the mold to mold the main body and cover of the device.

According to the present invention, a molded product having a circuit pattern is molded through the above steps.

[Description of embodiments of the invention]

Examples will be described in detail below with reference to the figures.

FIGS. 1A and 1B show a perspective view and a cross-sectional view of a molded product according to the present invention, which is a case/cover for an electric appliance such as the aforementioned calculator. The case 1 has a plane part 1A and side views 1B, 1B, and is entirely made of plastic resin polycarbonate by injection molding. On the inner surface of the case 1, a flat portion 1A and land portions 1c ₁ , 1c _{2 . .} . of circuit patterns 1c, 1c, .
On the surface of c, the land portions of the circuit patterns 1c, 1c, .

Next, the manufacturing method will be described in detail with reference to FIG. 2 and subsequent figures.

In Fig. 2, 2A is the movable mold plate of the mold, 2B
indicates the fixed side template of the mold, and each template 2A, 2B
A molding cavity is formed on the mating surfaces.

The movable mold plate 2A is opened and closed by a drive means (not shown) to open and close the mold.

A molten resin injection cylinder (not shown) is connected to the stationary template 2B, and the resin is injected from the injection cylinder into the cavity through the sprue 2b.

Next, the process will be explained step by step.

() Insulating layer formation process.

First, the movable template 2A is opened, and the first mask 4 is attached to the cavity surface of the movable template 2A.

The first mask 4 is made of an insulating rubber material,
It covers the cavity surface 4a of the portion corresponding to the land portion of the circuit pattern, and has openings 4b, 4b, . . . that expose the other surface.

After fixing the first mask, a composition for forming an insulating layer is deposited, and this deposition is carried out as follows.

In this adhesion operation, a powder composition containing an insulating material is put into a coating gun shown by reference numeral 6 in FIG. 3, and is sprayed onto the first mask 4 in the manner of spray painting. The resin composition for forming the insulating layer is Aromatex, an acrylic resin manufactured by Mitsui Toatsu Chemical Co., Ltd.
A powder composition containing AP-1648 having an average particle size of 10 μm was placed in the coating gun.

The coating gun 6 is configured to be movable toward the center of the molds 2A and 2B so that the spray port faces the cavity surface to which the first mask 4 is attached after the mold is opened, or the mold is opened manually. The first mask is inserted into a mold and the powder composition is sprayed onto the exposed cavity surface of the first mask.

The movable side template 2A is made of metal material and connected to ground. The powder composition in the coating gun is sprayed at a spraying pressure of 1 to 2 kg/cm ² . Since the mold 2A is grounded, the voltage is set to 0, and the spray port of the electrostatic coating gun 6 is set at approximately -70 Kv with respect to the mold 2A, and the spouted powder is approximately -70 Kv with respect to the mold.
Charge to 70Kv. When the powder is sprayed onto the cavity surface under these conditions, the powder composition adheres to the cavity exposed surface and the first mask as shown in Figure 3, and the powder composition is negatively charged to the mold. It maintains an electrostatic adsorption state.

When the first mask 4 is removed, the insulating composition 1D adheres to the entire surface of the cavity, leaving only the openings, as shown in FIG.

() Step of forming a circuit pattern After the insulating composition 1D is applied to the cavity surface, the second mask 8 is placed over the cavity surface and fixed.

The second mask 8 includes circuit pattern portions 1c, 1c...
Openings exposing the land portions 1c ₁ , 1c ₁ . . . are provided.

After attaching the second mask 8, the powder composition forming the circuit pattern portion and the land portion is applied to the fifth mask.
Apply with a paint gun 6 as shown in the figure. Circuit pattern portions 1c, 1c and land portions 1c ₁ , 1
The powder composition for forming c ₁ is prepared by kneading, cooling, and pulverizing a metal powder such as nickel as a conductive material and a thermoplastic resin such as an acrylic resin by heating and melting the mixture.

In this example, nickel powder, type 255 manufactured by Inc. Limited Japan Branch Co., Ltd. was used as the conductive material.
90% and Mitsui Toatsu Chemical Co., Ltd. as a thermoplastic resin.
A powder composition containing 10% by weight of Aromatex AP-1648, an acrylic resin, and having an average particle size of 10 μm was placed in the coating gun 6 and used.

After the spraying, when the second mask 8 is removed, the circuit patterns 1c, _1c , .
c ₁ ... is formed.

() After the circuit pattern and land portions are sprayed, the second mask 8 is removed, the mold is closed, and the case body is formed.

Molding is carried out by injecting polycarbonate resin at 300℃ from an injection cylinder (not shown) at a pressure of 1000Kg/ ^cm2 .
This is done by injecting into the mold cavity as shown in the figure.

After injection molding, the mold is cooled, the mold is opened, and the molded product 1 is taken out.

The molded product 1 is molded as shown in FIGS. 1A and B, and the land portions 1c ₁ , 1c _{1 .} . . of the circuit pattern portion are exposed on the inner surface thereof, and the land portions 1c ₁ , 1c ₁ .
The other surfaces of the molded product are covered with the insulating layer 1D, and the circuit pattern parts 1c, 1c, . . . are sandwiched between the insulating layer 1D and the molded resin.

〔Effect of the invention〕

According to the present invention, in the molded product 1 according to the present invention, only the land portions 1c ₁ , 1c _{1 .} . . to which circuit components are soldered are exposed on the molded product surface, and the circuit patterns 1c, 1c . It is embedded inside the composition 1D and has a structure in which contact with external electrical parts and conductors is cut off, and has high electrical stability.

Further, the circuit pattern portions 1c, 1c, . . . are embedded in the resin part of the molded product, and have excellent effects such as not being damaged or broken even by external impact.

[Brief explanation of the drawing]

FIG. 1A is a perspective view of a molded product according to the present invention;
Figure B is a cross-sectional view taken along the line A-A in Figure 1, Figure 2 is a diagram of the mold opening and the first mask fixedly installed, Figure 3 is an explanatory diagram of the process of spraying the insulating layer, and Figure 4 is the first mask removed. FIG. 5 is a state diagram showing the state in which the circuit pattern composition is sprayed, and FIG. 6 is an explanatory diagram of the molding process. 2A, 2B... Mold, 4, 6... First and second masks, 4, 7... First and second masks.

Claims (1)

[Scope of Claims] 1. A molded product formed by molding a molding resin material having a circuit pattern made of a conductive material, the insulating material covering a portion of the circuit pattern other than the land portion of the circuit pattern. The insulating layer made of a resin material and the circuit pattern part are located between the insulating layer and the molded part made of the molding resin material, and the land part of the circuit pattern is exposed from the insulating layer to the surface of the molded product. A resin molded product with a circuit pattern characterized by the fact that it is exposed. 2. In a method for molding a resin molded product having a circuit pattern, () attaching a first mask to the cavity surface of a molding die to mask areas other than those corresponding to the land portions of the circuit pattern, and attaching an insulating resin material; a first step; () attaching a second mask with an opening in the circuit pattern portion after attaching the insulating resin material;
a second step of attaching a conductive material; and () a step of molding the molded article with a molding resin material that molds the resin molded article after the second step. Molding method for resin molded products.