JPH07290449A - Sheet like electromagnetic shield molding material and production thereof - Google Patents

Abstract

PURPOSE:To obtain a molded product excellent in electromagnetic wave shield effect by a smimple manufacturing process. CONSTITUTION:In a sheet like electromagnetic wave shield molding material, both of upper and rear surfaces of a conductive sheet l are covered with resin layers 5 each formed from a compsn. prepared by adding a glass fiber 2 to a crosslinkable resin 3 and films 4 are applied to the outer surfaces of the resin layer 5. In the production of the sheet like electromagnetic wave shield molding material, two processes each continuously delivering the long film 4 to continuously coating the surface thereof with the crosslinkable resin 3 and adding the glass fiber 2 to the surface of the formed resin layer to obtain a sheet layer are provided. A long conductive sheet 1 is continuously delivered to the surfaces being in contact with the resin 3 of the upper and lower sheet layers obtained in these processes and the films 4 are pressed to the surfaces of the upper and lower sheet layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-shaped electromagnetic wave shield molding material used for electronic equipment, electric equipment, computers, communication equipment and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, electromagnetic wave shielding molding materials have been prepared by adding metal fibers such as copper fibers or stainless fibers or conductive fibers such as carbon fibers to a resin and mixing and dispersing them. The molded product using the electromagnetic wave shielding molding material thus obtained has a part in contact with the conductive fiber and a part in non-contact with the conductive fiber, and the conductivity performance differs locally. That is, there is a problem in that the electromagnetic wave shielding effect varies depending on the location of the molded product, resulting in lack of reliability.

In addition, molded products such as ABS resin are made of aluminum,
Molded products for electromagnetic wave shielding obtained by vapor-depositing or plating metals such as copper and zinc require a vapor-deposition or plating after molding once, which complicates the manufacturing process and reduces man-hours. There was a problem of hanging.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sheet having a simple manufacturing process and capable of obtaining a molded article having an excellent electromagnetic wave shielding effect. To provide a shaped electromagnetic wave shield molding material and a manufacturing method thereof.

[0005]

A sheet-like electromagnetic wave shielding molding material according to claim 1 of the present invention is a conductive sheet 1.
The upper and lower surfaces of the resin are covered with resin layers 5 and 5 in which the glass fiber 2 is added to the crosslinkable resin 3, and the films 4 and 4 are adhered to the outer surfaces of the upper and lower resin layers 5 and 5, respectively. To do.

In the sheet-shaped electromagnetic wave shielding molding material according to claim 2 of the present invention, the conductive sheet 1 has a thickness of 10 to 10.
It is characterized by being an aluminum foil or a copper foil of 200 μm.

In the sheet-shaped electromagnetic wave shielding molding material according to claim 3 of the present invention, the glass fiber 2 has a length of 6 to 50.
1 mm for all sheet-shaped electromagnetic wave shield molding materials
It is characterized by containing 0 to 50% by weight.

The sheet-shaped electromagnetic wave shielding molding material according to a fourth aspect of the present invention is characterized in that the resin 3 contains a liquid or paste unsaturated polyester resin or a phenol resin.

According to a fifth aspect of the present invention, in the method for producing a sheet-shaped electromagnetic wave shielding molding material, a long film 4 is continuously drawn out, and the surface of the film 4 is continuously coated with the crosslinkable resin 3. Then, two sets of steps for adding the glass fiber 2 to the resin 3 to obtain the sheet layer 11 are provided.
The long conductive sheet 1 is continuously fed to the surfaces of the upper and lower sheet layers 11 and 11 contacting with the resins 3 and 3 obtained in the assembly process, and the films 4 and 4 on the surfaces of the upper and lower sheet layers 11 and 11 are continuously fed out. Is characterized by pressing.

[0010]

The sheet-shaped electromagnetic wave shielding molding material according to any one of claims 1 to 4 of the present invention is such that the conductive sheet 1 is covered on both upper and lower sides with resin layers 5 and 5 in which a glass fiber 2 is added to a crosslinkable resin 3. On the outer surfaces of the upper and lower resin layers 5, 5, the film 4,
Since 4 is applied, there are some parts that are in contact with each other, such as conductive fibers, and some parts that are not in contact with each other. Therefore, the conductivity performance does not vary depending on the local area, and the conductivity performance is stable. is doing. That is, the electromagnetic wave shielding effect is constant regardless of the location of the molded product, and the reliability is excellent.

In addition, molded products such as ABS resin are made of aluminum,
A complicated manufacturing process such as a vapor deposition or plating process is required after the molding process, such as a molded product for electromagnetic shielding obtained by vapor deposition or plating of a metal such as copper or zinc. It is unnecessary.

According to the method for producing a sheet-shaped electromagnetic wave shielding molding material of the fifth aspect of the present invention, a sheet-shaped electromagnetic wave shielding molding material can be continuously produced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings related to the embodiments.

First, an embodiment of the electromagnetic wave shield molding material will be described. FIG. 1 shows a sectional view of the electromagnetic wave shield molding material of the present invention. As shown in FIG. 1, the sheet-shaped electromagnetic wave shielding molding material of the present invention is a state in which glass fiber 2 is added to resin 3 having crosslinkable properties on both sides of conductive sheet 1 and glass fiber 2 is impregnated with resin 3. Resin layer 5
Is covered with. The films 4 and 4 are arranged on the surfaces of the upper and lower resin layers 5 and 5 opposite to the surfaces in contact with the conductive sheet 1. That is, in the sheet-shaped electromagnetic wave shielding molding material of the present invention, the resin layer 5 is formed on both upper and lower surfaces of the conductive sheet 1.
The upper and lower resin layers 5 and 5 are covered with and the films 4 and 4 are adhered to them.

The conductive sheet 1 is made of, for example, a metal foil such as an aluminum foil or a copper foil, a carbon fiber mat, a carbon fiber mat on which a metal such as stainless is deposited, or a carbon fiber coated with a metal. A mat or the like is used. The thickness of the conductive sheet 1 is preferably 10 to 200 μm. That is, when the thickness of the conductive sheet 1 is less than 10 μm, the conductive sheet 1 is easily broken when the sheet-shaped electromagnetic wave shielding molding material is molded, and when the thickness of the conductive sheet 1 exceeds 200 μm, The specific gravity of the sheet-shaped electromagnetic wave shielding molding material and the molded product increases.

The glass fiber 2 has, for example, a diameter of 10
The thickness of about 13 μm is used. This glass fiber 2
Preferably has a length of 6 to 50 mm and is contained in an amount of 10 to 50% by weight based on the total amount of the sheet-shaped electromagnetic wave shielding molding material. That is, when the length of the glass fiber 2 is less than 6 mm, the mechanical strength of the molded product is weakened, and
If it exceeds the range, the dispersion of the glass fibers 2 becomes poor, and the quality such as the strength of the molded product is partially varied and becomes non-uniform. Further, when the content of the glass fiber 2 is less than 10% by weight based on the total amount of the sheet-shaped electromagnetic wave shielding molding material, the mechanical strength of the molded product becomes weak and the glass fiber 2
When the content of the above is more than 50% by weight with respect to the total amount of the sheet-shaped electromagnetic wave shielding molding material, the amount of the glass fiber 2 is too large compared to the amount of the resin 3, and the glass fiber 2 is not well impregnated with the resin 3. The impregnation becomes poor, and the appearance of the molded product deteriorates.

The resin 3 contains, for example, a liquid or pasty unsaturated polyester resin or a phenol resin such as resole.

The sheet-shaped electromagnetic wave shield molding material
1m²The weight per unit is preferably 0.5 to 6 kg.
Good Sheet-shaped electromagnetic shielding material 1m²Ah
If the weight is less than 0.5 kg, the resin 3
Since the amount of coating on the rum 4 is small, the variation is large.
1m of sheet-shaped electromagnetic wave shield molding material ²
If the weight per unit exceeds 6 kg, glass fiber 2
Is too much compared to the amount of resin 3, the glass fiber 2 resin
3 did not impregnate well, resulting in poor impregnation and the appearance of the molded product
become worse.

As the film 4, for example, a polypropylene film or a polyethylene film is used.

Next, an embodiment of the method for producing the sheet-shaped electromagnetic wave shielding molding material of the present invention will be described. Figure 2
FIG. 3 is a schematic view of a method for producing a sheet-shaped electromagnetic wave shielding molding material of the present invention.

A long film 4 such as a long polypropylene film or polyethylene film is continuously fed out from the film roll 6 shown in FIG. At the outlet of the dip tank 7 when passing through the dip tank 7 which is transferred by the film 4 impregnation conveyor 15 and filled with a resin 3 such as liquid or pasty unsaturated polyester resin or phenol resin such as resole The thickness of the resin 3 continuously applied to the surface of the film 4 is adjusted to be constant by the doctor blade 8 provided. Then, the continuously fed roving glass 9 is cut by a chopper 10 into glass fibers 2 having a predetermined length within a length of 6 to 50 mm, and the content of the glass fibers 2 is a sheet-shaped electromagnetic wave shield molding material. The glass fiber 2 is added onto the resin 3 applied to the surface of the film 4 so that the predetermined content is 10 to 50% by weight with respect to the total amount, and the sheet layer 11 is obtained. Two sets of steps for obtaining this sheet layer 11 are provided,
Upper and lower sheet layers 11, 11 obtained by these two sets of steps
Of the conductive sheet roll 12 on the surface in contact with the resin 3, 3
A continuous conductive sheet 1 such as a long aluminum foil or copper foil having a thickness of 10 to 200 μm is continuously fed out, and the films 4 and 4 attached to the outer surfaces of the upper and lower sheet layers 11 and 11 are pressed by a press roll. By pressing, glass fiber 2
Is impregnated with resin 3 and the glass fibers are dispersed therein to obtain a sheet-shaped electromagnetic wave shield molding material. The electromagnetic wave shielding molding material is wound up by a winding roll 14 of the electromagnetic wave shielding molding material.

Next, an embodiment of a molded product using the sheet-shaped electromagnetic wave shielding molding material of the present invention will be described.
The sheet-shaped electromagnetic wave shield molding material is used at 20 to 50 ° C.
Aged for about 1 to 5 days to thicken the resin 3, peel off the film 4 and cut into a predetermined size, and heat and pressurize in the mold of the molding machine to obtain a molded product having excellent electromagnetic wave shielding properties. To get That is, the sheet-shaped electromagnetic wave shielding molding material of the present invention is a resin layer 5 in which glass fibers 2 are added to a crosslinkable resin 3 on the upper and lower surfaces of the conductive sheet 1 around a continuous conductive sheet 1. This resin layer 5, 5 covered
Since the films 4 and 4 are adhered to the outer surface of the, there are portions that are in contact with each other, such as conductive fibers, and portions that are not in contact, and there is no difference in the conductivity performance depending on the local area. Conductive performance is stable. That is,
The electromagnetic wave shielding effect does not vary depending on the location of the molded product and is constant, and the reliability is excellent.

In addition, molded products such as ABS resin, aluminum,
A complicated manufacturing process such as a vapor deposition or plating process is required after the molding process, such as a molded product for electromagnetic shielding obtained by vapor deposition or plating of a metal such as copper or zinc. It is unnecessary.

Further, according to the method for producing the sheet-shaped electromagnetic wave shielding molding material of the present invention, the sheet-shaped electromagnetic wave shielding molding material can be continuously produced.

A specific example of the embodiment will be described below. For Examples 1 to 3, the composition shown in Table 1 was used,
Polymeric 9350Z (manufactured by Takeda Pharmaceutical Co., Ltd.) is used as the unsaturated polyester resin used in these, and P is a resol which is liquid at 25 ° C. as the phenol resin.
OR (manufactured by Matsushita Electric Works, Ltd.) was used to obtain a sheet-shaped electromagnetic wave shield molding material. This molding material was molded using a molding machine under the conditions of 170 ° C. for 120 seconds to obtain a flat molded product having a length of 200 mm and a width of 250 mm. As Comparative Example 1,
An aluminum-plated product of a flat plate of ABS resin having a length of 200 mm and a width of 250 mm was used.

[0026]

[Table 1]

As a result, the molded products using the sheet-shaped electromagnetic wave shielding molding materials of Examples 1 to 3 have the same electromagnetic wave shielding effect as the molded product of Comparative Example 1,
Moreover, the shape imparting and the electromagnetic wave shielding property imparting are completed in one step.

The electromagnetic wave shielding effect indicates the degree to which the energy from the surface can be attenuated, is expressed in decibel (dB), and is measured by the KEC method. 0
At -10 dB, there is almost no electromagnetic wave shielding effect and 10
At ~ 30 dB, the minimum electromagnetic wave shielding effect,
The average electromagnetic wave shielding effect is 30 to 60 dB, and generally, the electromagnetic wave shielding effect may be 60 dB or more.

[0029]

EFFECTS OF THE INVENTION According to the sheet-shaped electromagnetic wave shielding molding material according to the first to fourth aspects of the present invention, a molded product having a simple manufacturing process and an excellent electromagnetic wave shielding effect can be obtained.

According to the method for producing a sheet-shaped electromagnetic wave shield molding material according to the fifth aspect of the present invention, a sheet-shaped electromagnetic wave shield molding material that achieves the above effects can be continuously produced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a sheet-shaped electromagnetic wave shield molding material according to an example of the present invention.

FIG. 2 is a schematic view of a method for producing a sheet-shaped electromagnetic wave shield molding material according to an example of the present invention.

[Explanation of symbols]

 1 Conductive Sheet 2 Glass Fiber 3 Resin 4 Film 5 Resin Layer 11 Sheet Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B29K 67:00 309: 08 705: 02 705: 10

Claims (5)

[Claims] 1. A conductive sheet (1) is covered on both upper and lower surfaces with a resin layer (5, 5) obtained by adding a glass fiber (2) to a crosslinkable resin (3), and the upper and lower resin layers (5, 5). A sheet-like electromagnetic wave shielding molding material, characterized in that the film (4, 4) is adhered to the outer surface of (5). 2. The conductive sheet (1) has a thickness of 10 to 2
The sheet-shaped electromagnetic wave shield molding material according to claim 1, which is an aluminum foil or a copper foil having a thickness of 00 μm. 3. The glass fiber (2) has a length of 6 to 50 m.
10 for the total sheet-shaped electromagnetic wave shield molding material in m
The sheet-shaped electromagnetic wave shielding molding material according to claim 1 or 2, characterized in that the electromagnetic wave shielding molding material is contained in an amount of -50% by weight. 4. The sheet-shaped electromagnetic wave shield molding material according to claim 1, wherein the resin (3) contains a liquid or pasty unsaturated polyester resin or a phenol resin. . 5. A continuous film (4) is continuously fed out, a crosslinkable resin (3) is continuously applied to the surface of this film (4), and a glass fiber is applied onto this resin (3). Two sets of steps of adding (2) to obtain the sheet layer (11) are provided, and upper and lower sheet layers (1
1. The long conductive sheet (1) is continuously fed to the surface of the (1, 11) contacting the resin (3, 3), and the films (4, 4) on the surfaces of the upper and lower sheet layers (11, 11) are applied. It presses, The manufacturing method of the sheet-like electromagnetic wave shield molding material in any one of the Claims 1-4 characterized by the above-mentioned.