JP2002198678A - Casing for shielding electromagnetic wave and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a casing for shielding an electromagnetic wave having both high airtightness and conductivity, and a method of manufacturing the same. SOLUTION: This casing for shielding an electromagnetic wave includes an electrically non-conducting casing 12 which is molded in a required shape from a thermoplastic resin, a sealing gasket 14 which is made of an elastic body and of which lower portion 14b is embedded at a predetermined position in the casing 12, a primer layer 18 which integrally covers the upper portion 14a of this sealing gasket 14 and the casing 12, and a metal plating layer 20 deposited on the surface of this primer layer 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casing for electromagnetic wave shielding and a method for manufacturing the same, and more particularly, to a casing which is preferably used as a housing member for electronic equipment and has good electromagnetic and mechanical sealing. The present invention relates to an electromagnetic wave shielding casing that can be provided, and a method for manufacturing the casing having electromagnetic shielding properties.

[0002]

2. Description of the Related Art Office electronic devices such as computers and other industrial electronic devices such as sequencers incorporating a microcomputer as a control element may malfunction due to disturbances such as electromagnetic waves entering the device from the outside. It is known that there is In addition, these electronic devices often generate electromagnetic waves to the outside of the device housing during operation and become a harmful noise source. In order to protect the electronic device from interference of this kind of electromagnetic wave (EMI) and interference by lower frequency radio waves (RFI), and to prevent leakage of electromagnetic waves to the outside, an electromagnetic wave shield (shielding) is used. ) Is generally applied to the equipment housing.

As a specific means of the shield, there is a method of using a component which is previously shielded for a capacitor, a coil, or the like when designing a printed circuit board, or a method of shielding an electronic device housing. , Various levels of measures have been taken. At the housing level, when using a plastic housing that has a high degree of freedom in shape and is advantageous in terms of lightness, productivity, etc., it is possible to reflect electromagnetic waves by applying metal plating to the housing in a complex manner. There is a method to make it. A housing of an electronic device generally includes at least two parts, a main body that stores an electronic device unit and a lid that seals the inside of the main unit, and a parting line (joint) for these many components.
There is a possibility that electromagnetic waves may enter and exit from the installation site of the connector and connector terminals and the like, and it is necessary to effectively prevent this.

The above-mentioned parting lines, connector terminals, etc. are installed in an exposed state outdoors, PDA which has been widely spread in recent years, portable information equipment represented by a mobile notebook personal computer, and the like. In the case of electronic devices that are intended to be carried around, it is possible that they will be exposed to automobile exhaust gas, airborne dust and other acid rain outdoors. Sufficient airtightness that can be prevented is also required. Therefore, a technique has been implemented in which, for example, a soft sheet-shaped conductive member is attached to a target portion of the housing to prevent electromagnetic waves and rain from entering the inside of the housing. This conductive member is intended to prevent intrusion of rain and the like by reliably filling gaps and the like of the division line when a plurality of housings are united, and to shield electromagnetic waves. Generally referred to as a sealing gasket for electromagnetic wave shielding. Therefore, this term is used in this application.

[0005] As a method of combining the electromagnetic shielding property against EMI and the mechanical sealing property against moisture and moisture, a metal fiber cloth or a metal foil is used for an elastic body (foam, elastomer, etc.). Are wound to form a sealing gasket, a sealing gasket obtained by adding a conductive filler such as a carbon material to an elastic body, or a conductive substance such as a metal powder to have conductivity.

[0006]

However, in the case of the above-mentioned method, the following disadvantages are pointed out. In other words, conductive fibers, conductive cloths, and other conductive wire meshes that form part of these sealing gaskets lack material flexibility, and are considerably compared to polyurethane foam and the like that form the core material of the sealing gaskets. It is rigid. For this reason, when the above-mentioned division line forms small irregularities in a place or is formed so as to be curved with a relatively small curvature, the conductive fibers and the wire mesh are hardened when the sealing gasket is provided. Due to its solidity, it is difficult to follow these shape changes,
The gaps cannot be completely filled due to wrinkles, and the invasion and leakage of electromagnetic waves are allowed through the gaps. Further, the airtightness against rainwater, exhaust gas and dust is incomplete and cannot be put to practical use. Although a method using a foil instead of the conductive fiber or the wire mesh is also considered, in this case,
When the lid is repeatedly opened and closed, a gap is generated due to plastic deformation of the metal, so that the contact resistance becomes unstable. In addition to the case where the effect of the EMI shield cannot be obtained, the airtightness may not be exhibited.

[0007] In the case of the method, there is a track record in special applications such as the military, and a method of adding silver particles as a conductive substance to impart conductivity is mentioned. However, the silver particles are not only expensive but also In a composition having a resistance value of 1 Ωcm or less that ensures a sufficient EMI shielding property,
There is a disadvantage that the elastic hardness is increased, the degree of freedom of deformation is impaired, and the sealing gasket becomes unsuitable. Therefore, in place of the silver particles, copper particles, silver-plated copper particles or nickel particles may be used. In this case, the cost can be reduced, but the hardness is not sufficiently improved yet. Airtightness cannot be ensured.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems associated with the prior art, and has been proposed in order to solve the problem in a favorable manner. An electromagnetic shielding casing having both high airtightness and conductivity is provided. It is an object of the present invention to provide a method of manufacturing a housing.

[0009]

SUMMARY OF THE INVENTION In order to overcome the above-mentioned problems and achieve the intended object, an electromagnetic wave shielding casing according to the present invention is formed from a thermoplastic resin into a required shape, and is electrically nonconductive. A housing, a sealing gasket made of an elastic material and having a lower portion embedded and disposed at a predetermined position of the housing, and an upper portion covered with the housing and embedded in the housing. It is characterized by comprising a primer layer integrally covering the exposed gasket and a metal plating layer deposited on the surface of the primer layer.

In order to overcome the above-mentioned problems and achieve the intended object, a method for manufacturing an electromagnetic shielding casing according to another invention of the present application is to form an electrically non-conductive casing of a required shape from a thermoplastic resin. The lower part of the gasket for sealing is embedded in a required portion of the housing, and a primer obtained by dissolving a thermoplastic resin with an organic solvent is common to the housing and the upper part of the gasket embedded in the housing. The primer layer is formed by applying and hardening to form a primer layer, and the primer layer is subjected to electroless plating or electrolytic plating to deposit a required metal plating layer.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a housing for an electromagnetic wave shield and a method of manufacturing the same according to the present invention.

A housing 10 according to a preferred embodiment of the present invention comprises:
As shown in FIGS. 1 and 2, a housing 12 made of a thermoplastic resin and accommodating a required electronic device therein, and a housing 12 disposed at a required position of the housing 12, and the housing 12 is closed. The sealing gasket 14 which sometimes exhibits high sealing properties, and a thermoplastic resin made of the same material as the housing 12,
2 and a gasket 14 for sealing, a primer layer 18 continuously formed on the gasket 14, and a metal plating layer 20 formed on the primer layer 18 by electroless plating or the like.

The housing 12 is made of, for example, ABS resin, modified PPO resin, PC resin, PC / ABS resin or PC / ABS resin.
It is molded by a conventionally known molding method such as injection molding or extrusion molding using a thermoplastic resin such as ASA resin which can be etched with chromic acid. A sealing gasket 14, which will be described later, is provided at a portion to be contacted when the housing 12 is closed by another member such as a lid member, that is, at a bonding surface 12a in order to improve adhesion between the housing 12 and another member. However, in order to efficiently attach the sealing gasket 14 and the like, a required groove 12b may be provided in the joint surface 12a (see FIG. 2).

As shown in FIG. 2, the sealing gasket 14 includes a lower portion 14b embedded corresponding to a groove 12b provided between the housing 12 and another member serving as a parting line, and the joining surface. And an upper portion 14a protruding above 12a. Specifically, a method of attaching a sealing gasket 14 prepared in advance in a shape that is embedded in correspondence with the groove 12b in another step, or directly to an installation site of the sealing gasket 14 such as the groove 12b, Gasket for sealing 1
Any of the methods for forming 4 is employed. A device that shields electromagnetic waves and the like entering or exiting from the housing 12 closed by fitting with another member or the like, and exhibits airtightness that can prevent intrusion of moisture or the like from an external environment. It is. In particular, the density is set to be 0.8 g / cm ³ or less in order to secure softness so as to express good airtightness.

The sealing gasket 14 has a required hardness, is not violated by corrosive gas and moisture that can enter from the outside, and can be used for a long period of time. For example, a solid material such as silicone or urethane is used. An elastic body made of a body or a foam is preferably used. In the case of a foam, a foam having a surface film called a skin layer on its surface is preferable.

The primer layer 18 serves as a base on which the casing 12 and the sealing gasket 14 are integrated, and on which a metal plating layer 20 described later can be sufficiently adhered (see FIG. 2). As the material, the same material as the material constituting the housing 12, for example, ABS resin, modified PPO
Resin, PC resin, PC / ABS resin or PC / ASA
A thermoplastic resin such as a resin that can be etched with chromic acid is used, and a primer obtained by dissolving the thermoplastic resin at a predetermined concentration with various organic solvents is used. Due to the formation of the primer layer 18, the sealing gasket 14 is covered on one side (the lower side in FIG. 2) by the housing 12 and on the other side (the upper side in FIG. 2) by the primer layer 18. Become. For this reason, a uniform metal plating layer 20 can be formed on the housing 12 and the sealing gasket 14 irrespective of the difference in the material of the housing 12 and the sealing gasket 14 and the irregularities in shape.

The thickness of the primer layer 18 after application and drying and curing is such that the pretreatment such as etching required for forming the metal plating layer 20 can be sufficiently performed.
That is, the thickness is preferably about 10 μm. If it is thinner than this, sufficient etching becomes impossible, and if it is too thick, the hardness increases and the flexibility of the sealing gasket 14 that is covered is reduced, as well as the shape followability, and the sealing performance of the housing 12 deteriorates. So be careful.

When a silicone-based substance is used as the sealing gasket 14, since the adhesion and adhesion between the sealing gasket 14 and the primer layer 18 can hardly be expected, the primer layer Prior to the application of 18, the adhesive layer 16 exhibiting adhesiveness to the silicone material is formed to a required thickness.

As the adhesive layer 16, a silicone-based adhesive mainly composed of a moisture-curable resin such as a moisture-curable silicone resin is preferably used. The thickness of the adhesive layer 16 is preferably such that the thickness after application and drying and curing does not hinder the formation of the primer layer 18 and ensures sufficient adhesiveness, that is, about 10 μm (FIG. 2). reference).

The above-mentioned moisture-curable resin is mainly known in the field of adhesives. The moisture-curable resin absorbs moisture in the air to form a cross-link in the structure, and the cross-linkable resin is solidified. The compounded resin formulation is generally referred to. In the moisture-curable resin, a hydrolyzable functional group in the structure and a silanol group generated by moisture cause a condensation reaction to cause cross-linking, and are released from the oligomer by the condensation reaction. Depending on various condensation reaction by-products, they are classified into acetic acid type, alcohol type, oxime type, amine type, amide type, aminoxy type and acetone type (see Silicone Handbook, published by Nikkan Kogyo Shimbun).

The metal plating layer 20 imparts conductivity to the housing 10 to exhibit a desired electromagnetic wave shielding property. The metal plating layer 20 is usually a lower metal plating layer 20a having a high conductivity and exhibiting a desired EMI shielding property, and an upper corrosion resistance metal plating layer 20 exhibiting a high corrosion resistance.
2b (see FIG. 2). The thickness of the conductive metal plating layer 20a and the corrosion-resistant metal plating layer 20b together can sufficiently follow the deformation of the sealing gasket 14 due to compression or the like, and the thickness does not cause cracking or the like. A certain range of about 0.5 to 2 μm is preferable.

Examples of the electroless plating metal forming the conductive metal plating layer 20a include electroless gold, electroless silver and electroless copper, and have high reflectivity for reflecting an incident electromagnetic wave with a small thickness. The use of electroless copper, which has high conductivity, has a low elastic modulus, and when deposited on the surface of the core material 14, does not impair its softness and facilitates the management of an electroless plating bath. Is preferred.
The deposited thickness is preferably about 0.2 to 2 μm. If the thickness is smaller than this, the required conductivity cannot be achieved. If the thickness is too large, not only the softness of the sealing gasket 14 is impaired, Manufacturing costs and time will be increased.

Examples of the corrosion-resistant metal forming the corrosion-resistant metal plating layer 20b include nickel-phosphorus, nickel-boron, tin, gold, palladium and chromium. As the thickness at which the corrosion-resistant metal plating layer is deposited,
The thickness is preferably about 0.1 to 1 μm. If the thickness is smaller than this, the required corrosion resistance cannot be obtained.

[0024]

Manufacturing method As shown in FIGS. 3 and 4, the electromagnetic wave shielding casing 10 has a casing producing step S1, a sealing gasket producing / attaching step S2, a primer layer applying step S3, a conducting step S4 and a final step. It is manufactured through S5. The casing manufacturing step S1 is a step of manufacturing and processing the casing 12 having a required shape by a conventionally known molding method such as injection molding.

The sealing gasket production / attachment step S2 includes:
This is a step of attaching the sealing gasket 14 to a predetermined position such as the groove 12b of the joint surface 12a of the housing 12, and a case where the sealing gasket 14 having a required shape is manufactured in another step and attached to the housing 12. The groove 12
In some cases, the sealing gasket 14 is directly manufactured and attached to a predetermined portion such as b by injecting the raw material of the sealing gasket 14.

The groove 12b is formed by a method described later.
To produce a sealing gasket 14 having a shape corresponding to
The lower portion 14b of the sealing gasket 14 is
2b (see FIG. 4B).
In this method, a sealing gasket material is injected into the groove 12b and the like using a machine tool such as an XY axis robot (see FIG. 4A), and a sealing gasket 14 is formed in the groove 12b. How to In the case of this method, since the volume of the gasket material for sealing expands due to the foaming reaction after the injection, it is necessary to control the injection amount in consideration of the expansion coefficient.

As a specific method for manufacturing the sealing gasket 14, a silicone foam or a urethane elastomer is used as a main material, and a mechanical foaming method in which a required amount of air or an inert gas is mixed with the main material, A foaming agent corresponding to the main raw material (in the case of a silicone elastomer, the elimination reaction of hydrogen (H) from Si-H groups is used; in the case of a urethane elastomer, carbon dioxide generated by the reaction of an isocyanate group and water is used. ) Is suitably employed, and any other method may be employed as long as the density is 0.8 g / cm ³ or less.

Particularly in the case of the method, the sealing gasket 1
As a raw material of No. 4, a two-part mixed room temperature curing type material which can be controlled so as to start curing after injection and can be cured at room temperature after injection is suitably used. Such a sealing gasket 1 by injecting a raw material into a predetermined position of the housing 12.
4 is described in detail in Patent No. 3 devised by the present applicant.
No. 041546, JP-A-10-44
The method described in JP 186 is detailed. In addition, when this method is adopted, there is an advantage that the casing 12 and the sealing gasket 14 are firmly adhered to each other due to the adhesiveness developed when the sealing gasket raw material is cured.

The primer layer applying step S3 is performed in accordance with the type of the sealing gasket 14.
31 and a primer layer providing step S32. The step of providing a primer layer S32 includes the steps of:
Upper part 14a of sealing gasket 14 embedded in
This is a step of forming a primer layer 18 which is a base serving as a base of the metal plating layer 20 formed in a later-described conductive step S4 (see FIG. 4C). Specifically, the above-mentioned ABS resin, modified PPO resin, PC resin, PC / AB used as a raw material of the casing 12 are used.
It is carried out by a method capable of sufficiently dissolving a thermoplastic resin which can be etched with chromic acid such as S resin or PC / ASA resin in a solvent capable of dissolving, and forming a uniform layer under control such as spray coating.

The adhesive layer applying step S31 is an optional additional step performed when the adhesive layer 16 is required as described above. Specifically, an adhesive such as a moisture-curable resin that expresses the required adhesiveness to a silicone-based substance,
For example, it is applied by a method capable of forming a uniform layer under control such as spray coating. Since the moisture-curable resin generally has a high viscosity, it can be applied by a roll coater or the like, and the concentration can be adjusted with a solvent such as xylene, so that a uniform and thin adhesive layer 16 can be easily formed. Further, since the curing is performed by the atmospheric humidity, the curing speed can be easily controlled by controlling the humidity at the time of application to the housing 12 and the sealing gasket 14.

In the conductive step S4, which is performed subsequent to the primer layer applying step S3, a plating metal having high conductivity and a softness which does not impair the softness of the sealing gasket 14 is removed on the primer layer 18. A first plating step S32 of forming a conductive metal plating layer 20a having a predetermined thickness, which is applied by electrolytic plating, and electroless plating or electrolytic plating to obtain high corrosion resistance on the conductive metal plating layer 20a. It comprises a second plating step S33 for applying and forming a corrosion-resistant metal plating layer 20b having a predetermined thickness, and a pretreatment step S31 to be performed prior to each of the plating steps S32 and S33. At the time of shifting from the first plating step S32 to the second plating step S33, necessary washing with water, activation with a chemical, drying and the like are performed as necessary.

The pre-treatment step S31 includes an etching process or the like which is performed to continuously cover the housing 12 and the sealing gasket 14 and form the metal plating layer 20 on the integrally formed primer layer 18. This is a stage for performing preprocessing. Neutralization and accelerator treatment after etching, which are performed along with this etching, are also performed at this stage.

The first plating step S32 is a step of forming a conductive metal plating layer 20a from electroless copper or the like which exhibits high conductivity by electroless plating (see FIG. 4 (d)). The plating step S33 is a step of forming the corrosion-resistant metal plating layer 20b from metal nickel or the like that exhibits high corrosion resistance by electroless plating or electrolytic plating.
(See FIG. 4 (e)). In particular, it is preferable to use electroless plating suitable for forming a thin layer without the need for power supply, and it is preferable to use electroless nickel-phosphorus alloy, electroless tin, electroless silver or electroless gold. Is done.

Through the above steps S1, S2, S3 and S4, the electromagnetic wave shielding casing 10 having desired EMI shielding properties and airtightness can be obtained. The final step S5, which is finally performed, is a step in which the electromagnetic wave shielding casing 10 is subjected to final post-processing and a predetermined inspection to obtain a final product.

[0035]

[Experimental Examples] Hereinafter, a method of manufacturing a casing for electromagnetic wave shielding according to the present invention and preferable experimental examples of physical properties of the casing manufactured by this method will be described. However, the present invention is not limited to these experimental examples. is not.

(Experiment 1) A sealing gasket made of a silicone foam manufactured in advance is integrated with a housing.

(Manufacturing method) 1. Case manufacturing step S1 A PC / ABS resin (trade name: TB902G; manufactured by Mitsubishi Rayon Co., Ltd.) was used as a raw material, and a width of 1.0 m was applied to an edge portion serving as a joint.
Approximately 50 × 15 with a groove having a semicircular cross section of m
It was manufactured by injection molding a 0 × 10 substantially box-shaped (resin molded product thickness 2.0 mm) casing.

2. Sealing gasket production / attachment step S2 A thickness of 20 mm with a groove having a semicircular cross section of 0.9 mm in width
A PTFE-made plate is prepared, and a two-liquid room-temperature-curable foamable silicone rubber (trade name: Tosfoam 5000 series; manufactured by GE Toshiba Silicone Co., Ltd.) is stirred and mixed at a liquid A: liquid B weight ratio = 100: 10. Then, it is applied to the grooves of the production plate at room temperature. Then, the raw material overflowing from the groove was removed by scraping using the upper surface of the production plate as a guide, and left as it was for 30 minutes to foam and harden. To complete the foam hardening reaction, the mixture was heated using a hot air circulating drier at a temperature of 100 ° C. for 30 minutes, and then the completed sealing gasket was taken out of the groove. The sealing gasket obtained had a diameter of 1.0 mm and a density of 0.6 g / c.
skin layer m ³ was one formed on the surface. Then, this gasket for sealing was fitted into the groove of the housing manufactured in the housing manufacturing step S1 and attached.

3. Primer Layer Providing Step S3 (1) Adhesive Layer Providing Step S31: A moisture-curable silicone-based adhesive ( A 50% toluene solution of trade name (Super X; manufactured by Cemedine) was spray-coated to a dry thickness of about 10 μm, and dried and cured at room temperature to form an adhesive layer. (2) Primer layer application step S32: Then, ABS paint
(Trade name: Top Magic Coat; manufactured by Okuno Pharmaceutical Co., Ltd.) was spray-coated so as to have a dry thickness of about 10 μm, and dried and cured at room temperature to form a primer layer.

4. Conducting step S4 (1) Pretreatment step S31: Dipping in a degreasing solution containing 20 g / L of sodium sulfate and 20 g / L of sodium phosphate at a temperature of 50 ° C. for 4 minutes. And after washing with water, 400 g / L of chromic anhydride, 400 g / 98% sulfuric acid
The etching was performed by immersion in an etching solution composed of L at a temperature of 68 ° C. for 5 minutes. Then, after sufficient washing with water, the sample is immersed in a neutralizing solution of 35% hydrochloric acid 50 ml / L for 1 minute at room temperature for neutralization, and further washed with water and passed through a pre-dip tank of 35% hydrochloric acid 180 ml / L. And immersed in a catalyst bath consisting of 30 ml / L of palladium tin catalyst (trade name: Catalyst C; manufactured by Okuno Pharmaceutical Co., Ltd.) and 200 ml / L of 35% saltwater at a temperature of 35 ° C. for 2 minutes and washed with water Thereafter, an activator (trade name: Accelerator X; manufactured by Okuno Pharmaceutical Industries) 0.5 g / L and 98% sulfuric acid 10
It was immersed in an accelerator bath consisting of 0 ml / L to give palladium metal. (2) First plating step S32: After washing with water, electroless copper plating bath
(Product name: TSP-810, standard formulation of electroless copper; manufactured by Okuno Pharmaceutical Co., Ltd.) was subjected to electroless plating at a temperature of 55 ° C. for 30 minutes to form a conductive metal plating layer made of electroless copper. The thickness of the conductive metal plating layer was 2 μm. (3) Second plating step S33: After washing with water, a corrosion-resistant metal plating layer made of electrolytic nickel in an electrolytic nickel plating bath (TSP-48, nickel standard prescription; manufactured by Okuno Pharmaceutical) at a temperature of 50 ° C. for 10 minutes. Was formed. The thickness of the corrosion-resistant metal plating layer was about 0.3 μm.

5. Finishing Step S5 Washing and drying were sufficiently performed to obtain a casing for electromagnetic wave shielding.

(Experiment 2) A sealing gasket made of a silicone foam is directly formed on a housing and integrated therewith.

(Manufacturing method) 1. Case manufacturing step S1 PC / AS resin containing carbon fiber (trade name: FA420CA;
Using a raw material made of Mitsubishi Rayon, a substantially box-shaped (approximately 50 x 150 x 10) box with a semi-circular cross-section with a width of 1.0 mm was formed at the edge to be joined. (2.0 mm) by injection molding.

2. Sealing gasket production / attachment step S2 Two-liquid room temperature-curable foamable silicone rubber (trade name: Tosfoam 5000 series; manufactured by GE Toshiba Silicone Co., Ltd.) is applied to the groove portion by weight of liquid A: liquid B Ratio = 100: 1
Under the condition of 0, the mixture is mixed by a general-purpose two-liquid mixing and discharging device attached to the XY-axis robot, poured into a bead having a width of 0.5 mm, and left as it is at room temperature for 30 minutes to foam and harden. A sealing gasket of about 1.0 mm silicone foam was formed.

A primer layer providing step S3, a conductive step S4
The finishing step S5 is the same as the “primer layer applying step S3, the conducting step S4, and the finishing step S5” in Experiment 1 described above, and thus will not be described.

(Experiment 3) A sealing gasket made of a urethane foam is directly formed on a housing and integrated therewith.

(Manufacturing method) 1. Case manufacturing step S1 Using an ABS resin (trade name: VP-8M; manufactured by Mitsubishi Rayon) as a raw material, a groove having a semicircular cross section having a width of 1.0 mm was formed at an edge portion serving as a joint. Formed, dimensions about 50 × 150 × 10
Was molded by injection molding a substantially box-shaped (a resin molded product having a thickness of 2.0 mm) casing. 2. Sealing gasket production and mounting process S2

A two-component urethane foam material (trade name: MT-20; manufactured by INOAC CORPORATION) was attached to the XY-axis robot in the above groove portion under the condition of a liquid A: liquid B weight ratio = 100: 70. Mixed with a general-purpose two-liquid mixing and discharging device, and injected into a bead with a width of 0.5 mm.
It was allowed to stand at room temperature for 30 minutes for foaming and curing to form a sealing gasket made of a urethane foam having a height and width of about 1.5 mm.

In the primer layer applying step S3, the sealing gasket is made of urethane foam, so that the adhesive layer applying step S31 was not performed, and only the primer layer applying step S32 was performed. In addition, the conductive step S4 and the finishing step S4
5 is the same as the “layer applying step S3, the conductive step S4, and the finishing step S5” in Experiment 1 described above.
Omitted.

(Evaluation and Results) According to each of the above-described production methods, the obtained test specimens of Experiment 1, the test specimens of Experiment 2, and the test specimens of Experiment 3 were evaluated as follows. Softness of gasket for sealing, adhesion of plating, EMI
Shielding and watertightness were performed. the detail is right below.

Softness of sealing gasket: 50% CLD was used as an index. 50% CLD is AS
In accordance with TM D3574 Test C-94, the compression load at the time when the height of the sealing gasket reaches 50% of the previously measured height is measured by reading from a graph. 50% CLD of test specimens according to experiments 1, 2 and 3
Were all within the range of 10 to 35 N / 100 mm. This can be translated into ASKERC hardness,
The angle was 1 to 3 °, and it was confirmed that the film was very gentle.

Plating adhesion: A compression operation in which the operation of pushing in 25% of the thickness of the sealing gasket was repeated 10 times was performed. Then, as shown in Table 1, the peeling of the metal plating layer immediately after the heat-resistant cycle, after the moisture-heat cycle, and after the cold-heat cycle was performed was visually confirmed. Regarding the state of the test pieces according to Experiments 1, 2, and 3, no peeling was observed immediately after and after any cycle, and sufficient adhesion of plating was confirmed.

[0053]

[Table 1]

EMI Shielding Property: The center of the iron plate was cut out in a frame shape by 50 × 50 in a shield effect measuring jig based on the KEC method, and 4 m from the end of a 60 × 60 × 2 mm ABS plate.
Experiment 2 and Experiment 3 at a position of m so as to have a width of 1 mm.
The sealing gasket raw materials used in Step 2 were similarly injected and cured to form sealing gaskets having a height of about 1.5 mm and a width of about 2 mm. A metal plating layer is formed on the sealing gasket in the same manner, and the EMI shielding property of the obtained specimen is measured by a spectrum analyzer (trade name: 8560A; manufactured by Hewlett-Packard) having a tracking generator in a frequency band of 1 MHz to 1 GHz. Using the attenuation ratio of the intensity of the transmitted wave to the intensity of the incident wave as the shielding effect, the shielding characteristics of the electric wave and the magnetic wave were measured. Tables 2 and 3 below show a reference table of the shielding effect and its quality for reference, and the measurement results. As a result, it was confirmed that there was no leakage of radio waves and the like from the sealing gasket.

[0055]

[Table 2]

[0056]

[Table 3]

Waterproofness: As shown in FIG. 5, each of the obtained test pieces was fixed to an ABS plate having a size of 50.times.150.times.10 with a total of six clamps applied with a load of 500 g. Then, a test according to “Waterproof test of electric machine equipment and protection class against invasion of solid matter” in accordance with Jls C60920-1993 was performed. That is, after being immersed in water for 5 minutes, all the clamps were removed, and the intrusion of water into the inside of the test specimen was visually confirmed. Ten specimens were prepared for each specimen and tested ten times. No water intrusion was observed, and high waterproofness was confirmed.

[0058]

As described above, according to the electromagnetic wave shielding casing and the method of manufacturing the same of the present invention, the sealing layer is provided by continuously forming the primer layer on the casing and the sealing gasket. Without affecting the softness of the gasket, and regardless of the material of the housing and the sealing gasket, it is possible to cover the metal plating layer capable of exhibiting the electromagnetic wave shielding effect. Thus, a housing having high airtightness and sufficient electromagnetic wave shielding properties can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an electromagnetic wave shielding casing according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II in FIG.

FIG. 3 is a flowchart illustrating a process of manufacturing an electromagnetic wave shielding casing according to the embodiment.

FIG. 4 is a process diagram showing a process of manufacturing the electromagnetic wave shielding casing according to the example in an enlarged state near a gasket.

FIG. 5 is a schematic view showing a method for measuring waterproofness according to an experimental example.

[Explanation of symbols]

 12 Housing 12b Groove 14 Sealing gasket 14a Upper part 14b Lower part 16 Adhesive layer 18 Primer layer 20 Metal plating layer 20a Conductive metal plating layer 20b Corrosion resistant metal plating layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takuhiro Sasao 1 Nakagawara, Takagawara-cho, Nishio-shi, Aichi F-term (reference) 4K022 AA13 AA41 BA08 BA14 BA31 BA36 CA02 CA06 DA01 4K024 AA03 AA09 AB02 AB17 BA12 BB21 BB28 BC04 GA16 5E321 AA03 BB23 BB44 GG01 GG05 GH07

Claims (15)

[Claims] Claims 1. A thermoplastic resin is formed into a required shape from a thermoplastic resin,
An electrically non-conductive housing (12); an elastic body made of a material;
A sealing gasket (14) in which (14b) is embedded and disposed, and is covered on the housing (12) and is embedded in the housing (12) to expose an upper portion (14a). Gasket (1
4) a primer layer (18) that also integrally covers the top, and a metal plating layer (2) deposited on the surface of the primer layer (18).
0). An electromagnetic wave shielding housing comprising: 2. The electromagnetic wave shielding case according to claim 1, wherein the material of the case (12) and the primer layer (18) is a thermoplastic resin that can be etched with chromic acid. 3. The electromagnetic wave shielding casing according to claim 1, wherein the elastic body constituting the sealing gasket is a polyurethane foam. 4. The electromagnetic wave shielding casing according to claim 1, wherein the elastic body constituting the sealing gasket is a silicone resin foam. 5. The casing (12) and the sealing gasket (1) are provided on the primer layer (18) by interposing an adhesive layer (16).
4) The casing for an electromagnetic wave shield according to claim 4, wherein the casing is integrally coated thereon. 6. The electromagnetic wave shielding casing according to claim 5, wherein said adhesive layer is made of a moisture-curable resin such as a moisture-curable silicone resin. 7. The metal plating layer according to claim 1, wherein said metal plating layer comprises a conductive metal plating layer for securing conductivity and a corrosion-resistant metal plating layer for exhibiting corrosion resistance. An electromagnetic wave shielding casing according to any of the claims. 8. The electromagnetic wave shielding casing according to claim 7, wherein said conductive metal plating layer (20a) is made of copper and said corrosion-resistant metal plating layer (20b) is made of nickel. 9. A housing (12) having a required shape and electrically non-conductive is formed from a thermoplastic resin, and a lower portion (14b) of a sealing gasket (14) is provided at a required portion of the housing (12). The housing (12) and the gasket embedded in the housing (12) include a primer obtained by dissolving a thermoplastic resin in an organic solvent.
The primer layer (18) is formed by commonly applying to the upper portion (14a) of (14) and curing, and the primer layer (18) is subjected to electroless plating or electrolytic plating to a required metal plating. A method for producing an electromagnetic wave shielding casing, wherein a layer (20) is deposited. 10. The electromagnetic wave shielding device according to claim 9, wherein the sealing gasket (14) is manufactured in a separate process, and a lower portion (14b) is embedded in a groove (12b) recessed in the housing (12). The method of manufacturing the housing. 11. The electromagnetic wave shield according to claim 9, wherein the sealing gasket (14) is formed directly by injecting a gasket material into a groove (12b) recessed at a predetermined portion of the housing (12). Method for manufacturing a housing for a computer. 12. The method according to claim 9, wherein the primer layer (18) is applied by spray coating. 13. An adhesive layer (16) is continuously formed on said housing (12) and sealing gasket (14) prior to forming said primer layer (18). A method for manufacturing the electromagnetic shielding casing according to any one of the above. 14. The method according to claim 13, wherein the adhesive layer is applied by spray coating. 15. The metal plating layer (20) comprises a conductive metal plating layer (20a) formed by electroless plating and a corrosion-resistant metal plating layer (20b) formed by electroless plating or electrolytic plating. The ninth to ninth embodiments are formed in a laminated manner.
5. The method for manufacturing an electromagnetic wave shielding casing according to any one of 4.