JPH0758477A - Integral-type electromagnetic shielding molded body and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a integral-type electromagnetic shielding molded body, which has little warpage, high adhesion and high handleability, as an integrally molded material. CONSTITUTION:An integral-type electromagnetic shielding molded material is formed by molding a copper-clad laminated board A, which has a copper foil 2 on the surface on at least one side of its surfaces and is formed in a thickness of 0.5mm of thinner, is molded integrally with a thermoplastic resin via a bonding agent layer 3 and making the layer 3 consist of one liquid-type epoxy bonding agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated electromagnetic wave shield molded body and a method for producing the same, and more particularly to an integrated electromagnetic wave shield molded body having less warp, good adhesiveness and good handleability, and the same. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Recently, audio, computer, 8
Electric products such as millivideos and mobile phones have advanced in performance, and along with this, there is an increasing need for miniaturization, weight reduction, and thinning. At the same time, electromagnetic noise generated from other electronic devices may cause the circuit to malfunction, so an electromagnetic shield that covers the entire printed wiring board and the circuit components is often provided. As this electromagnetic wave shield, a metal plate such as an aluminum or copper plate is generally provided inside the casing of an electronic device, or a resin in which conductive particles are kneaded in order to impart electromagnetic wave shielding property to the casing itself is used. It is used and used. However, with such a method, there is a limit to the thinning of the electronic device, and when a resin in which conductive particles are kneaded is used for the housing, the weight of the molded body increases, the coloring, and the shielding There is a problem that slip-out easily occurs.
Therefore, applying a conductive paint, spraying a metal such as zinc to provide a metal layer, providing a metal layer by electroless plating, or pasting a metal foil, the electromagnetic wave shielding function on the housing. Have.

However, in each of the above methods, when the conductive paint is applied, a sufficient electromagnetic wave shielding function cannot be imparted unless the paint is applied a plurality of times. Further, when the metal layer is formed by spraying a metal such as zinc, there is a problem that the adhesiveness between the plastic material and the metal and the ability of the metal to follow a three-dimensional shape are poor. Further, when the metal layer is provided by the electroless plating method, there is a problem that processing equipment and steps are significantly increased. Further, when a metal foil is attached, there are problems such as adhesion between plastic and metal, followability of metal to a three-dimensional shape, and oxidation and peeling of the metal foil. Therefore, a so-called integrated electromagnetic wave shield molding has been proposed in which an electromagnetic wave shield layer is closely formed on the inner surface of the casing of the electronic device. For example, JP-A-5
9-146808, JP-A-60-42899, JP-A-61-19198, and JP-B-3-668.
In Japanese Patent No. 38, etc., there is disclosed a simultaneous molding-integrated type electromagnetic wave shield molding characterized in that a sheet mixed with a conductive material is injection-molded with a thermoplastic resin to be integrated.

[0004]

[Problems to be solved by the invention] However,
In the above conventional method, since the electromagnetic wave shield layer uses a conductive substance, unless a large amount of a conductive substance is added, the effect of the electromagnetic wave shield does not increase, and increasing the addition amount causes the dynamics of the base resin to increase. The characteristics will be impaired, and the cost will be very high. Further, when a flexible printed wiring sheet is used as the copper-clad sheet, the base material is a plastic film, so that the rigidity is insufficient and the handling property of the board is poor when electronic components are mounted on the board by a robot or the like. There is.
Therefore, as a base material, a so-called rigid substrate, which is a substrate in which a cellulose paper, a glass non-woven fabric, a synthetic fiber cloth, or the like is impregnated with an epoxy resin or the like, and a copper foil or the like is attached to at least one surface thereof via a glass cloth or the like, is used. Although the handling problem is solved by this, the rigid substrate has a large thickness, and when integrally molded with the molding resin 5 as shown in FIG. 1b, when the molded body 5 is thin, it becomes an integrally molded body. When warpage occurs and the molded body itself does not warp, there is a problem that defective adhesion easily occurs between the rigid substrate A and the molded body 5. Therefore, an object of the present invention is to provide an integrated type electromagnetic wave shield molded body which has less warpage as an integrated molded body, has good adhesiveness, and has good handleability.

[0005]

The above object can be achieved by the present invention described below. That is, the present invention is an integral type electromagnetic wave shield molding formed by integrally molding a copper clad laminate having a copper foil on at least one surface and having a thickness of 0.5 mm or less and a thermoplastic resin via an adhesive layer. In the body, the above-mentioned adhesive layer is made of a one-pack type epoxy adhesive.

[0006]

[Function] By integrally molding a copper clad laminate having a thickness of 0.5 mm or less and a thermoplastic resin using a one-pack type epoxy adhesive, there is little warpage as an integrally molded product and good adhesiveness. In addition, it is possible to provide an integrated type electromagnetic wave shield molding having good handling property.

[0007]

The present invention will now be described in more detail with reference to the preferred embodiments shown in the drawings. The copper clad laminate A itself having a copper foil on at least one surface used in the present invention is the same as a conventionally known copper clad laminate, and any known copper clad laminate can be used in the present invention. I can. The copper-clad laminate A is a substrate obtained by impregnating a cellulose paper, a glass non-woven fabric, a synthetic fiber cloth or the like as a base material with an epoxy resin or the like, and attaching a copper foil or the like to at least one surface thereof via a glass cloth or the like. is there. The copper-clad laminate A is preferably flexible so as to follow the shape of the molded product. In order to impart flexibility, it is desirable to impregnate the base material with a flexible epoxy resin.

In the present invention, the flexible epoxy resin to be impregnated into the base material is a dimer acid-modified epoxy resin,
It contains a flexibility-imparting agent such as a rubber-modified epoxy resin and is usually mixed with a hard epoxy resin for use in impregnation. The hard epoxy resin is a hard epoxy resin containing a bisphenol A epoxy resin as a main component. The above epoxy resin may appropriately contain a curing agent, a curing accelerator, a filler, a colorant, and other additives. Such copper clad laminates are known to have various thicknesses, but in the present invention, those having a thickness of 0.5 mm or less, preferably 0.1 to 0.5 mm are used. If the thickness is less than 0.1 mm, the rigidity is insufficient, the handleability is insufficient, and the manufacturing cost is high. Further, if the thickness exceeds 0.5 mm, even if a one-pack type epoxy adhesive is used, it is not possible to sufficiently suppress the warpage of the integrally molded body. The integrated electromagnetic wave shield molding of the present invention is characterized in that the above-mentioned copper clad laminate and the thermoplastic resin molding are bonded to each other by a one-pack type epoxy adhesive.

As the adhesive for joining the copper clad laminate and the thermoplastic resin, a one-component curing type epoxy adhesive is used. The one-component curing type epoxy adhesive basically contains an epoxy resin and a curing agent. As the epoxy resin, it is preferable to use one having two or more epoxy groups in the molecule (for example, epi-bis type, polyether type, glycidyl ester type, etc.). The curing agent is preferably an anionic one such as a boron trifluoride complex compound, dicyandiamide, an organic acid anhydride, or diaminodiphenyl sulfone.

It is preferable that the epoxy resin and the curing agent contain an elastomer component for the purpose of relaxing the internal stress generated when the adhesive force of the adhesive is developed. As the elastomer component, an olefin-based elastomer and various other rubber-based elastomers can be used, but it is preferable to use an olefin-based elastomer because the adhesive strength is particularly good. The composition of the adhesive containing the elastomer component as described above is 35 to 45% by weight of the epoxy resin and 5 to 15% by weight of the curing agent, with the total of the epoxy resin + the curing agent + the elastomer component being 100% by weight. , 40-50 elastomer component
It is preferably wt%. Further, the above-mentioned adhesive has a solid content (epoxy resin + curing agent + elastomer component) of 20 to 3
It is preferably composed of 0% by weight and 70 to 80% by weight of the solvent. As the solvent, it is preferable to use a ketone solvent such as methyl isobutyl ketone (MIBK).

The thickness of the adhesive layer as described above is 5 μm or more, preferably about 5 to 15 μm. Thickness is 5 μm
If it is less than 1, the adhesive strength is weak, the copper-clad laminate and the injection resin are not sufficiently adhered, and the laminate may float.
If the thickness exceeds μm, the adhesive flows due to the injection pressure when the resin is injected, and the adhesive runs off from the laminate and adheres to the copper surface, resulting in poor appearance. The adhesive layer is applied to the substrate side by roll coating or screen printing, and is applied in a solution state in which solid content is dissolved in a solvent. Since the adhesive coated surface usually has tack,
Covered with release film before injection molding. The release film is usually coated with a release agent such as silicone, and a moisture-proof substrate is used to avoid the influence of moisture absorption of the adhesive. Biaxially oriented polyester is usually used. The thickness of the release film is usually 30 to 1
If the thickness is 00 μm and less than 30 μm, it is difficult to remove it before molding, and if it exceeds 100 μm, there is a problem in production cost.

Since the copper surface (electromagnetic wave shield layer) may be corroded when used for a long period of time, the surface of FIG.
It is desirable to provide the insulating resin layer 4 as shown in FIG. As the resin for the insulating resin layer 4, a thermoplastic resin such as a polyester resin, an acrylic resin, an epoxy resin, a polyurethane resin or a thermosetting resin can be used. The insulating resin layer 4 has a thickness of 1 to 15 μm, especially 3 to
It is preferably 10 μm. The insulating resin layer 4 can be formed on the copper surface of the copper clad laminate by a coating method such as screen printing. It can also be formed by laminating a film made of the above resin on the copper surface of the copper clad laminate.

Electromagnetic wave shielding film A and resin molding 5
Is integrated by injection molding. The resin for injection molding is not particularly limited as long as it can be injection-molded, and examples thereof include polyimide, polyamide, polyetherimide, polycarbonate, acrylonitrile-butadiene-styrene copolymer (ABS resin), and heat resistance. Sex AB
Various thermoplastic resins such as S resin, polyphenylene sulfide (PPS), polystyrene, fluorine resin, polyolefin such as polypropylene and polyethylene can be used. Among these, acrylonitrile-butadiene-styrene copolymer (ABS resin),
Heat resistant ABS resin, polycarbonate, polymer alloy of ABS resin and polycarbonate, polypropylene,
Polystyrene and the like are preferable.

As shown in FIGS. 1 and 2, the method for manufacturing the integral type electromagnetic wave shield molding of the present invention is such that the copper surface of the copper clad laminate A (FIG. 1a or c) is changed to the male surface 6 of the injection molding machine. Fixed to
In combination with the female die 7 having the injection gate 8, the molten resin is injected from the injection gate 8 to integrally form the copper clad laminate A with the resin molding 9 having a predetermined shape via the adhesive layer 3. Is the way. In FIG. 2, the injection molding die comprises a male die 6 and a female die 7, and a cavity 9 is formed when the male die 6 and the female die 7 are closed. Male 6 is
The surface is processed with good slipperiness (Teflox processing, etc.), various three-dimensional surfaces are formed according to the inner wall surface of the integrated electromagnetic wave shield molded body, and the copper clad laminate A of the flange portion is formed. At the exposed location, the mold fits perfectly. Further, the male die 6 may be provided with a suction port 10 for sucking and fixing the copper-clad laminate, and the flat portion of the tip of the male die 6 has a copper-clad laminate A (not shown).
There may be provided a retaining pin for fixing the. On the other hand, an injection gate 8 is provided at the center of the female die 7. still,
The female die 7 is movable in the left-right direction in the figure with respect to the male die 6.

When the copper clad laminate A is fixed at a predetermined position of the male die 6 as described above, the die is closed and a desired molten resin is injected from the injection gate 8, the molten material injected from the gate 8 is melted. The resin spreads in all directions along the adhesive layer 3 provided on the copper clad laminate A and fills the entire cavity. After the filling, the mold is cooled to an appropriate temperature and then the mold is opened to obtain a desired integrated electromagnetic wave shield molding. The copper-clad laminate A can be installed on the male mold 6 accurately by providing a detection mark at an appropriate position on the copper-clad laminate and using an optical positioning device or the like.

[0016]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. Examples and Comparative Examples As a copper-clad laminate, a one-component curing type epoxy adhesive (manufactured by ThreeBond Co., Ltd .: 1570) was applied to the surface opposite to the copper surface of CEL-514 (thickness 0.2 mm) manufactured by Shin-Kobe Electric. Was applied by screen printing at a rate of 7 μm (coating amount 8 g / m ² ) and the solvent in the adhesive was volatilized through a drying zone at 120 ° C. for 2 minutes. As a comparative example, an adhesive layer was similarly formed using polyester-based and vinyl chloride-vinyl acetate copolymer resin-based adhesives.

The copper clad laminate thus obtained was fixed on a male mold of a temperature-controlled injection molding mold so that the adhesive layer was on the side in contact with the molten resin, and after the mold was clamped, ABS resin,
A PBT resin and a PC resin (glass fiber reinforced) were injected to obtain an integral molding. The integral type electromagnetic wave shield molded body thus obtained was subjected to an environmental test, and its adhesiveness was evaluated by a breaking test of the molded body. These integrally molded bodies were used for electronic device cases. The results are shown in Table 1 together with the type of adhesive and the type of injection molding resin. Those using the one-component curing type epoxy adhesive (1570 products) are 120 ° C.
Was heat-treated for 1 hour.

[0018]

[Table 1] ◯: Good Δ: Weak adhesion X: Poor adhesion

Environmental test conditions Heat cycle test: 80 ° C. for 1 hour ← → −30 ° C.
1 hour 10 cycles Constant temperature and constant humidity test: 60 ° C 90% R.V. H. 24
0 hours Heat resistance test: 192 hours at 90 ° C Cold resistance test: 480 hours at -30 ° C

Note) (1): As a polyester adhesive, Toyobo Co., Ltd.
Made byron was used. (2): PVHS manufactured by Showa Ink Co., Ltd. was used as the vinyl chloride / vinyl acetate copolymer adhesive. (3): As the ABS resin, GT-R-40 manufactured by Denki Kagaku Kogyo Co., Ltd. was used. (4): As the PBT resin, 2092 manufactured by Polyplastics Co., Ltd. was used. (5): As the PC resin, NOVAREX 7025G20 (including 20% by weight of glass fiber) manufactured by Mitsubishi Kasei Co., Ltd. was used.

Example 2 Differences in warp of the integrally molded products obtained were compared by the difference in the thickness of the copper clad laminate. 0.2m for a copper clad laminate
m, 0.4mm, 0.5mm, 0.6mm, 0.8mm
And 1.0 mm were investigated. CEL-514 used a single-sided copper clad plate. As the injection resin, Novalex 7025G20 (containing 20% by weight of glass fiber) manufactured by Mitsubishi Kasei Co., Ltd. was used as a PC resin.

[0022]

[Table 2] ◯: No warpage occurs Δ: Some warpage occurs ×: Warpage occurs significantly

[0023]

As described above, according to the present invention, the thickness is 0.
By integrally molding a copper-clad laminate having a thickness of 5 mm or less and a thermoplastic resin using a one-pack type epoxy adhesive, it is possible to obtain less warpage as an integrally molded body, good adhesion, and good handling property. An integrated electromagnetic wave shield molding can be provided.

[0024]

[Brief description of drawings]

FIG. 1 is a view for explaining a cross section of a copper-clad laminate used in the present invention and an integrally formed copper-clad laminate with warpage.

FIG. 2 is a diagram illustrating a method for manufacturing an integrated copper-clad laminate molding.

[Explanation of symbols]

 A: Copper-clad laminate 1: Base material sheet 2: Copper foil 3: Adhesive layer 4: Insulating resin layer 5: Resin molded body 6: Male mold 7: Female mold 8: Injection gate 9: Resin molded body (cavity) 10: Suction port

Claims (2)

[Claims] 1. An integral type electromagnetic wave shield molding formed by integrally molding a copper-clad laminate having a copper foil on at least one surface and having a thickness of 0.5 mm or less and a thermoplastic resin via an adhesive layer. In the integrated electromagnetic wave shield molding, the adhesive layer is made of a one-pack type epoxy adhesive. 2. The copper surface of a copper-clad laminate having a copper foil on at least one surface and an adhesive layer formed on one surface and having a thickness of 0.5 mm or less is fixed to a male surface of an injection molding machine. And a female mold having an injection gate, and a molten thermoplastic resin is injected from the injection gate to integrally form the copper clad laminate with a resin molded body having a predetermined shape. Method for manufacturing shield molded body.