JP2000045062A - Electromagnetic preventing molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic preventing molding high in electromagnetic shielding characteristics and excellent in adhesion force and corrosion resistance. SOLUTION: This electromagnetic molding is composed of a plastic molding, a primary layer film of Cu formed on the surface of this plastic molding to a film thickness of 0.5 to 2.0 μm and a secondary layer film thickness of Ni formed on the primary layer film to a film thickness of 0.2 to 1.0 μm, and the surface of the plastic molding is exposed to the inside of the plasma of gaseous Ar and is successively exposed to the inside of the plasma of gaseous O2, and then, the primary layer film and the secondary layer film are formed by a vacuum method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic prevention molded article in which a metal film is formed on a plastic molded article.

[0002]

2. Description of the Related Art In recent years, devices such as personal computers, mobile phones, and PHSs have been widely used.
It is conceivable that other electronic devices may malfunction or affect the human body. Therefore, such devices need to be treated for electromagnetic prevention (electromagnetic wave shielding). There is a demand for an anti-magnetic molded article that is excellent in electromagnetic wave shielding effect, low in cost, excellent in mass productivity, and excellent in durability and corrosion resistance.

[0003] Conventionally, various electromagnetic wave shields have been applied to electric equipment and electronic equipment. There are known methods of mixing a conductive metal into a plastic molded body, applying a conductive paint, and forming a wet plating film or a metal film on the surface of the plastic molded body.

[0004]

As a method for forming a metal film on the surface of a plastic molded body, an electroless plating method has been conventionally used. In the electroless plating method, processes such as etching and addition of a catalyst are performed, and the adhesion between the plastic molded body and the metal is strong. However, there is a problem of waste liquid treatment of electroless plating and a problem of mass productivity that a plating time is long. Further, since metal adheres to both surfaces of the plastic molded product, when the plastic molded product is used as a product, it is necessary to apply painting or the like to one surface, which causes a problem of an increase in cost.

Further, in the method of forming a metal film on the surface of a plastic molded body by using a vacuum method, a method of forming a thick film of Al, a method of using a highly conductive Cu and a highly corrosion-resistant Ni, are used. The method of laminating is common. In order to increase the adhesion, it is necessary to apply a primer treatment, wet plating, or plasma cleaning to the plastic molded body. However, these methods have problems in productivity and cost.

In other words, the method of performing the primer treatment requires a coating facility and a drying facility, and also requires a masking operation for a portion where coating is unnecessary. The wet plating method requires a plating facility and a wastewater treatment facility, and also requires a masking operation and a painting operation for a portion not requiring plating.

The method of performing plasma cleaning with an inert gas such as Ar gas is effective in improving the adhesion such as initial adhesion, but has such an effect that it can withstand a long-time moisture resistance test and a salt spray test. Cannot be obtained.

[0008] Therefore, an object of the present invention is to provide an electromagnetic prevention molded article having high electromagnetic shielding properties, and excellent adhesion and corrosion resistance.

[0009]

Means for Solving the Problems In order to achieve the above-mentioned object, an electromagnetic prevention molded article of the present invention comprises a plastic molded article and a first Cu film formed on the surface of the plastic molded article.
An electromagnetically-resistant molded article comprising a layer coating and a second layer coating of Ni formed on the first layer coating, exposing the surface of the plastic molded article to plasma of Ar gas;
_After exposure to the plasma of the _two gases, the first layer coating and the second layer coating are formed by film formation by a vacuum method.

Preferably, the thickness of the first layer coating is 0.5 to 2.0 μm, and the thickness of the second layer coating is 0.2 to 1.0 μm.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a plasma treatment is performed by first exposing a plastic molded body to Ar gas plasma in a vacuum chamber, and then exposing the plastic molded article to O ₂ gas plasma. Subsequently, the thickness is 0.5 to 2.0 μm by a vacuum method.
Of a first layer film of Cu having a thickness of 0.2 to 1.0 μm.
A film forming process is performed in the procedure of forming a second layer coating of m of Ni to obtain an electromagnetic prevention molded body.

The plastic molded article used in the present invention is preferably made of ABS, a mixture of ABS and polycarbonate, polycarbonate, or the like, which is widely used in personal computers and mobile phones. Further, a resin such as polypropylene, which is conventionally considered to have low adhesion to metal, may be used.

In the plasma treatment, the surface of the plastic molded body becomes physically uneven due to the collision of Ar ions by exposing it to plasma of Ar gas, which is an inert gas, and the surface area increases. Subsequently, by exposing the plastic molded body to an O ₂ gas plasma, the surface of the plastic molded body is chemically etched into an active state, and the wettability with metal increases.

By performing the above-described plasma treatment, the anchor effect in the film-forming treatment is increased, and the affinity with the metal is increased. Therefore, a high adhesion between the plastic molded body and the metal film can be obtained.

The method of ionizing each gas may be any known method such as high frequency discharge, glow discharge, arc discharge, etc., and the gas plasma pressure is 1 × 10 ^-4.
It may be in the range of up to 5 × 10 ^-2 torr.

Further, in order to stabilize the plasma of O ₂ gas, Ar gas to O ₂ gas before ionization may be added 1-10%.

It is sufficient that the plasma treatment time is 1 minute to 10 minutes for exposure to Ar gas plasma and 30 seconds to 5 minutes for exposure to O ₂ gas plasma. If the plasma processing is performed for a longer time than this, the characteristics cannot be improved. On the contrary, if the temperature of the plastic molded body rises too much, the plastic molded body is deformed by heat or the structure of the plastic molded body is destroyed,
Plasma treatment over a long period of time is not preferable because the expected shielding properties cannot be obtained due to the metal coating.

The first layer film in the film forming process is desirably made of highly conductive Cu having a thickness of 0.5 to 2.0 μm. C
The thickness of the first layer coating of u affects the electromagnetic shielding properties,
A film thickness of 0.5 μm or more is required, and as the thickness increases, the electromagnetic shielding characteristics become higher. However, the electromagnetic shielding characteristics obtained with a film thickness of 2.0 μm are practically sufficient. Inferior and economically disadvantageous.

The first layer coating of Cu alone is insufficient in terms of weather resistance, corrosion resistance and mechanical properties. Therefore, Ni, which is more excellent in corrosion resistance than Cu, is used as the second layer coating in an amount of 0.2 to 0.2.
The film is formed with a thickness of 1.0 μm. 0.2 μm second layer coating
If the thickness is smaller, a large number of pinholes are generated, so that sufficient corrosion resistance cannot be obtained. On the other hand, if the thickness exceeds 1.0 μm, cracks and peeling occur due to internal stress in the metal film, which is not preferable.

The first layer coating and the second layer coating are formed by a vacuum method such as a vacuum deposition method, an ion plating method, and a sputtering method. Since the metal films produced by these vacuum methods have higher purity than metal films produced by a wet plating method or the like, a sufficient electromagnetic shielding effect can be obtained even with a thin metal film. In addition, since the film forming process is performed by a vacuum method, the process can be performed continuously with the plasma process performed as a pre-process, and the surface of the plastic molded body after the plasma process is not exposed to the atmosphere and is not contaminated. High adhesion between the body and the metal coating can be obtained.

[0021]

The present invention will be described in detail below with reference to examples.

Example 1 A 150 mm × 3 mm polypropylene substrate was wiped with ethanol, and an electron beam type ion plating apparatus (AIF-85 manufactured by Shinko Seiki Co., Ltd.) was used.
0SB) and evacuated to a degree of vacuum of 2 × 10 ⁻⁵ torr. Thereafter, Ar gas was introduced to 0.03 torr, and during glow discharge in which -800 V was applied to the counter electrode,
The substrate surface was exposed for 10 minutes. Subsequently, O ₂ gas was added to 0.
The substrate surface was exposed for 5 minutes during glow discharge in which the voltage was introduced up to 02 torr and -1000 V was applied to the counter electrode. Next, Cu in the form of a pellet is dissolved and evaporated by an electron beam,
The film was formed for 5 minutes. Subsequently, the hearth was rotated to melt and evaporate the Ni ingot with an electron beam, thereby forming a film for 12 minutes. When the film thickness of the obtained metal film was measured by X-ray fluorescence, the first layer film of Cu was 1.2 μm and the second layer of Ni was
The layer coating was 0.3 μm.

Table 1 summarizes the evaluation results of the obtained metal coatings.

[0024]

[Table 1] (Example 2) The same plasma processing and film forming processing as in Example 1 were performed except that the substrate made of the ABS resin was exposed to Ar gas plasma for 1 minute, and then exposed to O ₂ gas plasma for 1 minute. went. Fluorescent X
Line, the Cu first layer coating was 1.1 μm.
The second layer coating of m and Ni was 0.32 μm.

The evaluation results of the obtained metal coating were the same as the evaluation results of the metal coating of Example 1 shown in Table 1.

[0026]

According to the present invention, after performing the plasma treatment in the plasma of Ar gas and the plasma of O ₂ gas, the anti-magnetic molded article of the present invention has a first-layer coating of Cu having high conductivity and a high corrosion resistance. A metal coating composed of a second Ni coating and having excellent electromagnetic shielding properties is formed by a vacuum method. Since the surface of the plastic molded body is modified by the plasma treatment, the adhesion to the metal coating can be increased, and the corrosion resistance and weather resistance are excellent.

In addition, since the plasma processing and the film forming processing can be performed continuously, it can be manufactured at low cost and has an effect that the productivity is excellent.

Claims (3)

[Claims] 1. An electromagnetic prevention device comprising: a plastic molded body; a first layer coating of Cu formed on the surface of the plastic molded body; and a second layer coating of Ni formed on the first layer coating. A molded article, wherein the surface of the plastic molded article is Ar
An electromagnetically-resistant molded body, characterized in that the first layer coating and the second layer coating are formed by vacuum forming after being exposed to gas plasma and subsequently to O ₂ gas plasma. 2. The film thickness of the first layer coating is 0.5 to 2.0.
The molded article according to claim 1, which has a thickness of μm. 3. The film thickness of the second layer coating is 0.2 to 1.0.
The electromagnetically molded article according to claim 1 or 2, which has a diameter of µm.