JPH0821767B2 - Injection molded article having conductive pattern and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an injection-molded article in which a surface shape of a cloth and a conductive pattern on the cloth are precisely and firmly transferred to the surface, and a method for producing the same.

[Conventional technology]

2. Description of the Related Art In recent years, a synthetic resin injection molded container or the like having a pattern such as a printed wiring provided on the inner surface thereof has come to be used in electronic devices and the like. Traditionally to make these things,
A desired circuit pattern or the like is formed on a film or sheet of polyester or the like by printing or vacuum deposition using a conductive substance, and injection molding is performed using an injection molding die installed in the mold, and then the film is formed. Alternatively, a method has been adopted in which a sheet is peeled from a molded body and a circuit pattern or the like is transferred.

[Problems to be Solved by the Invention]

However, in this conventional method, the inserted synthetic resin film or sheet is deformed by the injection pressure, and the pattern is likely to be inaccurate.

Therefore, the injection pressure cannot be increased, and it is difficult to obtain a thin molded body. Further, when the injection pressure is low, the adhesion of the pattern is lowered and the conductivity is also impaired.

In the case of a resin having a high injection molding temperature, for example, engineering plastics, there is a problem that the inserted synthetic resin film or sheet is largely deformed by heat and may be melted.

Particularly in the case of engineering plastics that require a high injection molding temperature of 300 ° C. or higher, the above-mentioned conventional method cannot be practically carried out, and improvement has been desired.

An object of the present invention is to solve the above-mentioned problems of the conventional method and to provide an injection-molded article having a more excellent conductive pattern and surface aesthetics, and an economical and efficient manufacturing method thereof.

[Means for solving the problem]

In order to solve the above problems, the present inventor has variously studied transfer techniques in injection molding, and as a result, uses a cloth on which a predetermined pattern is formed by using a conductive material, and from this cloth to an injection molded body, the shape of the cloth surface is formed. At the same time, the inventors have found that the above problems can be solved all at once by transferring the pattern, and the present invention has been completed.

That is, the present invention provides a synthetic resin injection molded article in which the surface shape of the cloth and the conductive pattern on the cloth are simultaneously transferred, and as a method for producing the same, a pattern is formed with a conductive substance. After placing the cloth in the cavity of the mold so that the pattern is on the resin side, the mold is set, plasticized synthetic resin is injected, and then the cloth is peeled from the obtained injection-molded body. The present invention provides a method for producing an injection-molded article, in which the surface shape of the cloth and the conductive pattern on the cloth are simultaneously transferred to the surface.

 The present invention will be described in detail below.

First, in order to manufacture an injection-molded article to which the conductive pattern of the present invention is transferred, it is necessary to prepare a cloth used for the injection-molded article. The surface shape of the cloth, the texture pattern, etc. may be appropriately selected according to the purpose, but the material takes into consideration the type of resin used, especially the conditions such as resin temperature, resin pressure, mold temperature required for the injection and economic efficiency. Then you need to choose.

In general, most commercially available fabrics can be used in the case of general-purpose resins, but in the case of so-called engineering plastics, especially in the case of synthetic resins called super engineering plastics that require high temperature, high pressure, and high mold temperature for injection, Fabrics consisting of substantially non-thermoplastic fibers are preferred.

That is, in the case of engineering plastics whose plasticization temperature is 300 ° C. or higher and requires a high mold temperature, it is difficult for the ordinary thermoplastic fiber cloth to withstand the heat. In this case, natural fibers, recycled fibers, and inorganic fibers are used. It is necessary to use a fabric made of a fiber having a substantially non-thermoplastic property such as acrylic fiber. These fabrics usually withstand a mold temperature of up to about 200 ° C and have a low thermal conductivity of the fabric itself within a short time even at high temperatures during injection, while the resin surface cools down by the mold, so the fabric does not burn. It's done.

As a method for forming a pattern on the cloth, most of the generally known patterning methods are used, and among them, printing, particularly silk screen printing is preferable. In addition to vapor deposition and sputtering, patterning techniques such as chemical plating, electroplating, ion plating and etching can be used depending on the cloth and pretreatment. If the surface of the fabric is extremely uneven and patterning is difficult, a pattern may be formed on a thin, smooth surface of the fabric, and the back of the fabric may be lined with the highly uneven fabric for injection molding. it can.

As the conductive material for patterning used in the present invention, in addition to conductive inks that are generally commercially available, commercially available powders of gold, silver, copper and the like, conductive materials such as flakes and solvent thickeners and the like are appropriately blended. Can also be used. Of course, the metal can be directly vapor-deposited.

As a method for inserting the cloth, a conventional plastic film inserting method can be used. In this case, it is a simple method to attach the cloth to the mold using a double-sided tape or the like, and the cloth can be installed by an appropriate mechanical method. Alternatively, a commercially available in-mold device may be used.

The fabric may be peeled off from the injection-molded article obtained by molding by manual or mechanical methods.

Thus, an injection-molded article is obtained in which the conductive pattern is transferred onto the desired pattern.

[Action]

In the present invention, when the hot melt resin is injected into the mold,
The resin filled with the cloth partially set in the mold installed in the mold forms a molded body in which the cloth is attached to the surface. At this time, the pattern is simultaneously fixed by the action of heat and pressure, and when the cloth is peeled off, the cloth pattern and the cloth pattern are transferred onto the molded body.

On the other hand, when a conventional plastic sheet is used, the hot melt resin advances in a narrow passage having a long surface while compressing and eliminating the existing air, so that it contacts the airflow resistance, especially the mold. It is difficult to remove air on the side opposite to the pattern of the sheet, and air is left behind, so that transfer and molding are incomplete due to waviness and air pockets.

Further, in addition to the resistance of the excluded air, the sheet has high heat conduction, so that the surface of the injection resin is easily cooled, and the resistance of the resin flow is further increased, and as a result, the sheet is deformed.
Further, the plastic sheet may be softened and deformed or melted by the heat of the injection resin.

However, in the case of the present invention, the inserted fabric entirely contains air between the weaves and between the fibers, and the existing air of the inflowing resin component is easily compressed between the weave fibers by the injection resin pressure. Therefore, it is possible to avoid the above-mentioned adverse effects due to the air pool, the resistance of the air flow, and the like.

Further, since a fabric containing a large amount of air has low heat conductivity, rapid cooling of the resin surface at the moment of injection can be avoided, which helps to reduce the resistance of the resin flow and obtain a good surface condition. It is speculated that this allows the use of resins such as engineering plastics, which have a high plasticizing temperature.

Further, in the present invention, since the injection pressure can be increased and the thermal conductivity of the cloth used is low, the contact between the pattern surface and the injection resin can be performed at a high temperature. It is presumed that the adhesion will be good and the conductivity will be further improved. Moreover, it is considered that the unevenness of the cloth also contributes to the further improvement of the adhesion of the transfer pattern.

〔Example〕

 Examples of the present invention will be shown below.

Example 1 Silver powder (Fukuda Metal Foil AgC-A ) And acrylic
Paint (Cerinol VG medium made by Teikoku Ink Ltd. ) And heavy
Commercially available thin nylon with printing ink blended in a volume ratio of 5: 5
A printed wiring circuit was screen printed on the fabric. this
120mm length, 110mm width, 1.5mm thickness plastic cloth
It was installed using a tape in a box mold. Inner bottom of this mold
The surface is provided with a protrusion of about 5 mm.
Is provided with a printed wiring.

 Next, ABS resin (Styrac made by Asahi Kasei Tree)
Oil temperature 230 ℃, mold temperature 45 ℃, injection pressure 800Kg / cm²Injection molded with
Thus, a molded article to which the above-mentioned cloth is attached is obtained. From this molded product
The molded product obtained by peeling off the cloth has a good surface resistance of 0.49Ω.
A plastic with a printed wiring inside that has conductivity and adhesion.
It was a stick box.

Comparative example 1 It carried out like Example 1 except having used the polyester film in which the same pattern as Example was copper-sputtered. The result was that the transfer surface was easily peeled off and the adhesiveness was poor. Further, wrinkles were clearly observed on the protrusions on the bottom surface of the molded product due to the effect of residual air.

Therefore, when the injection pressure was increased to 1500 Kg / cm ² to mold the film in order to increase the peeling property, the film was melted and scattered, and it did not become a product at all.

Example 2 It was carried out under the same conditions as in Example 1 except that the injection pressure was raised to 1500 Kg / cm ² . As a result, a plastic box having a good conductive pattern transfer surface on the inner surface was obtained as in Example 1.

Example 3 The same mold as in Example 1 was used, and the resin was polyetherimine.
Resin (EPL Ultem ), The fabric is copper ammonia regeneration
Fiber (Asahi Kasei Bemberg ) Thin fabric, printing
The ink temperature and printing method are the same as in Example 1, and the resin temperature is 390
℃, mold temperature 95 ℃, injection pressure 1500Kg / cm²The cloth adheres to the inner surface with
Molded box. Box-shaped molding obtained by peeling the fabric from this
The product has a printed wiring with good conductivity and excellent adhesion.
It was a polyetherimide box on the surface.

Example 4 Resin temperature 380 ° C., polyether sulfone as resin
Tomo Kagaku VICTREX-PES ) Is the same as in Example 1 except that
It was carried out. The result is a good conductor with accurate inner surface and excellent adhesion.
Polyethersulfone with electro-conductive printed wiring transferred
A box was obtained.

〔The invention's effect〕

According to the present invention, it is possible to easily and economically transfer a printed circuit of good conductivity, which is free from wrinkles and undulations and is excellent in adhesion and adhesion, to an injection molded product. It can be said that this effect is extremely great especially for an injection-molded article of resin such as engineering plastics which requires a high injection temperature, which has been difficult to transfer conventionally.

Claims (6)

[Claims] 1. A synthetic resin injection molded article in which the surface shape of a cloth and a conductive pattern on the cloth are simultaneously transferred. 2. The injection molded article according to claim 1, wherein the synthetic resin is a resin which requires an injection molding temperature of 300 ° C. or higher. 3. A cloth on which a pattern is formed with a conductive material is placed in a cavity of a mold so that the pattern is on the resin side, the mold is set, and a plasticized synthetic resin is injected. Then, the method for producing an injection-molded article, wherein the surface shape of the cloth and the conductive pattern on the cloth are simultaneously transferred to the surface, which is characterized in that the cloth is peeled off from the obtained injection-molded article. 4. The method for producing an injection molded article according to claim 3, wherein the synthetic resin is a resin which requires an injection molding temperature of 300 ° C. or higher. 5. The fabric is a non-thermoplastic fabric.
Or the method for producing an injection-molded article according to item 4. 6. The method for producing an injection-molded article according to claim 5, wherein the non-thermoplastic fabric is a fabric composed of natural fibers, regenerated fibers, semi-regenerated fibers, inorganic fibers and acrylic fibers.