KR20090027304A - Fellet for absorption emi and method for manufacturing the same, cable using fellet for absorption emi - Google Patents

Abstract

A pellet for absorbing an EMI(Electromagnetic Interference), and a method for manufacturing the same, a wire and a cable using the same are provided to reduce a noise in a communication process by shielding an electromagnetic wave generated in the wire and the communication cable. An outermost side of a communication wire or cable(200) is coated with insulating coating(30b). A communication line(40) of two strands, a power line(50) of one strand, and an earth line of one strand(60) are arranged inside the communication line or cable. The pellet for absorbing an EMI is injection molded into the communication wire or cable. The pellet for absorbing the EMI has a noise suppressing function. The insulating coating made of the pellet for absorbing the EMI includes a metal flake absorbing the EMI. The metal contained in the pellet for absorbing the EMI absorbs the noise generated from the communication line.

Description

Pellet for electromagnetic wave absorption and manufacturing method thereof, wire and cable using pellet for electromagnetic wave absorption {Fellet for absorption EMI and method for manufacturing the same, Cable using fellet for absorption EMI}

The present invention relates to an electromagnetic wave absorbing pellet and a method for manufacturing the same, and an electric wire and a cable using the electromagnetic wave absorbing pellet. More specifically, after processing the metal powder in the form of a plate-shaped metal flake, it is mixed with a resin and pelletized The present invention relates to an electromagnetic wave absorbing pellet, a method for manufacturing the same, and a wire and cable using the electromagnetic wave absorbing pellet, which are capable of reducing noise while absorbing electromagnetic waves generated from electric wires and communication cables.

In recent years, as the use of various electric and electronic devices has rapidly increased, problems of electronic noise or electromagnetic interference (EMI) have emerged, and these noises generally have conduction noise and emission or radiation noise ( emission or radiation noise).

As a general means for solving the conducted noise, a noise filter is used, and it is necessary to electromagnetically insulate a predetermined space against radiation noise.

To this end, it is possible to store electrical and electronic equipment in a metallic or conductive case, to install a metal plate between two circuit boards, or to surround the cable with a metal foil, and to apply an electromagnetic wave absorber to the electrical and electronic device. Can be.

There is a rubber sheet using a metal mixture among the electromagnetic wave absorbers, but since the inorganic material and the polymer are in a mechanically mixed state, they are not only poor in physical properties but also have low heat resistance, and thus have a low electromagnetic wave absorption efficiency.

In particular, in the case of the rubber sheet as described above, because the resin containing a chlorine-based polyethylene (halogen group) is used, there is a problem in that damage caused by the generation of harmful gases (Cl, F, etc.) to the human body or peripheral devices.

In addition, most of the existing electromagnetic wave absorbers use only basic materials such as carbon, ferrite, and metal, which makes it difficult to process and difficult to control the thickness of the product. There is a problem in that there is a lack of a back to easily expose the disadvantages such as wear, etc., difficult to adjust the applied frequency.

In addition, there is an electromagnetic wave gasket applied to mobile phones, PDAs, etc., which further improves the above disadvantages, and is a form of wrapping conductive metal coating fibers on the outside of a sponge to prevent electromagnetic leakage between internal modules of a mobile phone or PDA. .

However, even in the case of the electromagnetic wave gasket as described above, there are problems that appear in the characteristics of the fiber, for example, due to the electric short phenomenon due to the silage of the gasket cutting portion, there are a number of problems such as malfunction of the equipment when applied.

Therefore, in recent years, electromagnetic wave absorbers using metal alloy materials that can cover the disadvantages of the various electromagnetic wave absorber products have been developed and applied to a lot of mobile phones, LCDs, PDAs, and the like.

For example, the main raw materials used as the electromagnetic wave absorber are SDST alloy, HIGH-FLUXE, Molypermalloy powder (MMP), Pure iron (Fe-Si, Fe-Si-Cr). , Amorphous (Amorphose, Fe-Si-Al-Cr), carbon coating Iron, nickel-zn ferrite (Ni-Zn ferrite), manganese-zn ferrite (Mn-Zn ferrite) powder and the like.

These powders are spherical powders having a horizontal to vertical ratio of 1 to 5, and partly provided with an electromagnetic wave absorber obtained by pasting or sheeting them.

However, when sheeting with spherical metal alloys as a raw material, the layer laminated inside the sheet is small, so it is difficult to expect sufficient electromagnetic wave absorbing performance, and to increase the thickness, since the application is limited in space, it is functional. There are disadvantages in terms of aspects and practicality.

That is, if the raw material powder used as the electromagnetic wave absorber is spherical, the permeability is lowered. Therefore, there is a limit in the applicable frequency band, and in the high frequency band, the absorption efficiency drops sharply.

In view of this, the applicant of the present invention, “The process of making a spherical metal alloy into a plate-shaped metal flake using an Attrition mill, the process of pasting the plate-shaped metal flake with a resin through high-speed stirring, Lamy By providing a method for manufacturing an electromagnetic wave absorber including a step of sheeting a metal paste on a release film through a rating treatment, and the pasting or sheeting electromagnetic wave absorber manufactured by the method, the manufacture can be carried out in various shapes and forms. It is possible to show excellent electromagnetic wave absorbing ability even in small volume, so it can be widely applied as electromagnetic wave absorber of devices with small and complicated structure such as digital camera, mobile phone, LCD, drive IC, PDA, wireless LAN, etc. Horizontal and vertical ratios can be increased without destroying Electromagnetic wave absorber and its manufacturing method which can expect excellent electromagnetic shielding and absorption effect in wideband including high frequency band because it can secure laminated alignment structure that can increase the number of times (Korean Registered Patent Publication No. 10-0463593 (Dec. 16, 2004).

In recent years, with the development of communication devices, electromagnetic waves are also generated in cables and wires connected to communication devices. In order to reduce noise between communications caused by the electromagnetic waves, the cable 200 is shown in FIG. A Cu braid 80 having a structure braided in the form of a net is insulated in the insulating coating 30a of the insulating coating 30a, and the braid 80 is a communication line 40, a power line 50, and an earth wire in the insulating coating 30a. 60) It is a structure that surrounds the back.

In addition, as another electromagnetic shielding method applied to cables and wires connected to communication devices, a ceramic core may be employed instead of the Cu braid, and an electromagnetic wave absorber sheet is attached to the inside of the outlet portion connected to the end of the cable. Doing.

Therefore, the Cu braid blocks the electromagnetic waves generated from the communication line, the power line, etc. in the cable, but there is a problem that the electromagnetic shielding effect is inferior as understood through the graph of FIG. .

The present invention has been made in view of the above, and the metal powder or ferrite powder is processed into a plate-shaped metal flake form, and then mixed with a polyolefin resin such as PE or CPE or PET resin pelletized SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnetic wave absorbing pellet and a method of manufacturing the same, which are applied to a communication cable and electromagnetic wave generating portions of various electric and electronic devices to reduce noise while absorbing electromagnetic wave.

It is still another object of the present invention to melt and inject a pellet for electromagnetic wave absorption and inject it into an insulating coating covering a communication line, a voice frequency current wire cable, a high frequency cable, a control cable, a power line, and so on while absorbing and shielding electromagnetic waves generated from wires and communication cables. An object of the present invention is to provide an electric wire and a cable using an electromagnetic wave absorbing pellet to reduce noise between communication.

One embodiment of the present invention for achieving the above object is a plate-shaped metal alloy using a grinding machine which is operated at a constant time and speed with a spherical metal alloy, which is a raw material, susbol blending, ceramic ball blending and surfactant addition Processing into flakes; And washing and drying the metal flakes with ethyl alcohol or methyl alcohol and water, wherein the metal flake powder and polyolefin resin are 35 to 95 wt% of PE or CPE or PET. : Compounding and stirring at a rate of 65 to 5% by weight to process into a metal compound; Mixing the metal compound by repeatedly passing the mixing roller to form a sheet; Pulverizing the sheeted product using a pulverizer and processing it into pellets; It provides a method for producing a pellet for electromagnetic wave absorption comprising a.

In a preferred embodiment, passing the pellets through a thermocompression roller; Discharging the pellets by the thermo-compression roller and discharging them into the sheet for absorbing electromagnetic waves in a sheet form; Forming an adhesive sheet for absorbing electromagnetic waves by applying an adhesive to one surface of the sheet for absorbing electromagnetic waves; It characterized in that it further comprises.

In another preferred embodiment, the raw material of the metal flakes for producing the pellet is Fe-Si alloy, Fe-Si-Cr alloy, amorphous metal (amorphous substance), SDST alloy, high flux (HIGH-FLUXE ), Molypermalloy powder (MMP), pure iron (Fe-Si, Fe-Si-Cr), amorphous (Amorphose, Fe-Si-Al-Cr), carbon coating iron, nickel-zinc It is characterized in that any one selected from ferrite (Ni-Zn ferrite), manganese-zinc ferrite (Mn-Zn ferrite) powder.

Another embodiment of the present invention for achieving the above object is: a communication wire, a power line, a communication wire in which the earth line is embedded, melting the pellets for absorbing electromagnetic waves, as an insulation coating wound around the communication line, power line, earth wire An electric wire and a cable using the electromagnetic wave absorption pellets which were injection-molded are provided.

Another embodiment of the present invention for achieving the above object is a USB cable in which a communication line, power line, earth line, etc., characterized in that the electromagnetic wave absorber attached to the connector of the USB cable, USB port for noise reduction Provided are electric wires and cables using pellets for absorbing electromagnetic waves.

Through the above problem solving means, the present invention can provide the following effects.

Pelletized metal flakes were mixed with a polyolefin resin such as PE or CPE or PET and passed through a thermal compression roller to be sheeted, and then attached to wires, communication cables, and electromagnetic wave generation parts of various electric and electronic devices. The noise of the communication signal can be reduced while absorbing and shielding electromagnetic waves.

In particular, by using the electromagnetic wave absorbing pellet according to the present invention as the insulation coating of the communication wire or cable for enclosing the communication line, power line and earth line, the noise between communication can be greatly reduced while absorbing and shielding the electromagnetic wave generated from the wire and the communication cable. have.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

According to the present invention, a metal powder, which is a metal raw material for absorbing electromagnetic waves, is processed into a plate-shaped metal flake, and then mixed with a resin and pelletized, so that the fillet can be used as an insulation coating of wires and communication cables. The main point is to reduce noise while absorbing electromagnetic waves generated from cables and the like.

Referring to the method for manufacturing the electromagnetic wave absorbing pellet of the present invention in order.

First, a spherical metal alloy, which is a raw material, is processed into a plate-shaped metal flake using a grinding mill that is operated at a constant time and speed with susbol blending, ceramic ball blending, and surfactant addition, and the metal flakes are ethyl alcohol. Alternatively, the process of washing by drying with methyl alcohol or mole is performed in the same manner as the manufacturing method that has already been registered by the present applicant (see Korean Patent Publication No. 10-0463593 (2004.12.16)).

That is, in the process of processing the metal flakes, the ratio of injecting the metal alloy and the susball in the case of using a 50l abrasive grinder metal alloy: Ø5 ball: Ø10 ball = 1: 2.8∼4.5: 2.3∼4.2 When using a metal alloy: Ø5 ball: Ø10 ball = 1: 2.8 to 4.5: 2.3 to 4.2, and when using a 10l abrasive grinder, the metal alloy: Ø5 ball: Ø10 ball = 1: 2.3 to 4.2: 2.8 to 4.5 In case of using 5l abrasion crusher, metal alloy: Ø3 ball: Ø5 ball = 1: 2.3 ~ 4.2: 2.8 ~ 4.5.

In this case, the metal alloy, that is, the raw material for producing the electromagnetic wave absorption pellets are Fe-Si alloy, Fe-Si-Cr alloy, amorphous metal (amorphous substance), sender alloy (SDST alloy), high flux (HIGH- FLUXE), Molypermalloy powder (MMP), Pure iron (Fe-Si, Fe-Si-Cr), Amorphose (Amorphose, Fe-Si-Al-Cr), Carbon coating Iron, Nickel-zinc ferrite (Ni -Zn ferrite, manganese-zinc ferrite (Mn-Zn ferrite) may be used any one selected from the powder, the susball may be made of SUS 301, 304 and the like.

In addition, the ratio of the surfactant added in the step of processing into the metal flakes is 0.005 to 0.03% by weight of oleic acid, 0.0001 to 0.003% by weight of triethanolamine, 0.005 to 0.03% by weight of tartaric acid, 0.0002 to 0.004% by weight of formic acid Can be added.

In this flat process, the metal alloy powder, the susball, and the surfactant are added into the abrasion mill and the time and speed of stirring are preferably about 3 to 12hr and about 200 to 400rpm, as shown in FIG. 6 through the above process. The metal flake powder processed into a flat powder is washed with ethyl alcohol or methyl alcohol, water and then naturally dried for about 36 to 48 hrs, or for about 6 to 12 hrs in a 60 to 120 ° C. dryer.

The aspect ratio of the finished metal flakes is about 150 to 450, which is significantly increased compared to metal alloys of about 1 to 5 degrees.

Next, using a flexible mixer, the metal flake powder and polyolefin resin such as PE or CPE or PET are blended and stirred at a ratio of 70 to 95% by weight: 30 to 5% by weight, and processed into a metal paste.

That is, the proportion of the metal flake powder in the total weight of 100% by weight of 35 to 95% by weight, PE or CPE or PET of 65 to 5% by weight, blended with each other and stirred, and as a lubricant fatty acid as an emulsifier during the formulation, 0.001 to 3.5% by weight of oleic acid, ethyl cellulose, tartaric acid, and nitro cellulose are added to 100% by weight of the total amount.

Next, the metal compound is repeatedly passed through the mixing roller so that the mixing between the metal flake and the polyolefin resin such as PE or CPE or PET can be made more uniform.

In more detail, the metal compound kneaded into a thin sheet-like shape through the mixing roller is repeatedly inserted into the inlet of the mixing roller, so that the mixing between the metal flake and PE or CPE or PET can be made more uniform. Make sure

Subsequently, the sheet-shaped metal paste mixed through the mixing roller is introduced into a grinder and processed into pellets.

The prepared electromagnetic wave absorbing pellets can be supplied to manufacturers and injection molding companies that manufacture wires and cables as they are, and can be used as insulation coating as described later by wire and cable companies.

On the other hand, a product in the form of a sheet that can attach the electromagnetic wave absorption pellets to the electromagnetic wave generation site, such as electronic devices can be made as follows.

First, the pellets are passed through a thermo compression roller, so that the roll of the compression roller is maintained at 35 ~ 80 ℃ so that the pellet can be easily melted and compressed.

Subsequently, the pellet is melted by the thermocompression roller, and when passed through the thermocompression roller, it is discharged into the sheet for absorbing electromagnetic waves in the form of a sheet.

Of course, the area and thickness of the electromagnetic wave absorbing sheet made of the pellets can be adjusted to a desired specification.

Thus, by applying an adhesive to one surface of the electromagnetic wave absorbing sheet is made of an electromagnetic wave absorbing adhesive sheet, by attaching the electromagnetic wave absorbing adhesive sheet to the portion of the electromagnetic wave generated in the various electronic devices, the function to absorb electromagnetic waves Will be

Here, the wire or cable structure using the electromagnetic wave absorption pellets prepared as described above are as follows.

2 is a schematic diagram illustrating a communication cable manufactured using the electromagnetic wave absorbing pellet according to the present invention.

As described above, the existing communication wire or cable 200 is wrapped with an insulating coating (30b) on the outermost side, therein two communication lines 40, one power line 50, one strand Ground wire 60 and the like are wired.

Here, by injection molding the electromagnetic wave absorbing pellet of the present invention manufactured as described above in the insulating coating (30b) of the communication wire or cable 200, it is possible to suppress the generation of noise between communications.

That is, by melting the pellets for absorbing electromagnetic waves of the present invention, injection molding into an insulating coating (30b) for winding the communication line 40, the power line 50, the earth line 60, the noise generated from the communication line 40 The effect of absorbing the insulating coating 30b injection molded into the electromagnetic wave absorbing pellets can be obtained.

In other words, the insulation coating 30b made of the electromagnetic wave absorbing pellet contains a metal flake that absorbs electromagnetic waves, and the metal flake absorbs the noise generated from the communication line.

Here, the electromagnetic wave shielding and noise removing effect of the wire and cable employing the film for electromagnetic wave absorption and shielding according to the present invention will be described through the following Examples and Test Examples.

Example

The insulation coating of the USB cable of the Samsung Techwin digital camera NV-1-83 model was manufactured using the electromagnetic wave absorption pellet of the present invention.

That is, the communication line, the power line, the earth line, etc. in the cable were covered with the insulation coating made from the pellet for electromagnetic wave absorption of this invention.

Comparative Example 1

A Cu braid with a braiding ratio of 75% was embedded in the insulation coating of the USB cable of Samsung Techwin's NV-1-83 digital camera.

That is, the Cu braid was wrapped around the communication line, power line, and earth line in the USB cable.

Comparative Example 2

Samsung Techwin Digital Camera NV-1-83 does not have any means of shielding or removing noise.

That is, no electromagnetic wave shielding or noise removing means is embedded in the insulation coating of the cable other than the communication line, power line, and earth line.

Test Examples 1-2

As Test Example 1, a burst test (Burst Test) is a method in which data is transmitted at high speed without interruption until the data transmission is completed. Test using AX2 instrument.

As a result, the cable according to Example 1 and Comparative Example 1 was measured as having a good data transmission state, and the cable of Comparative Example 2 without a separate electromagnetic shielding or noise removing means did not perform data transmission due to communication interference caused by noise. Was measured.

As Test Example 2, the communication data transmission state of the cable according to Examples and Comparative Examples 1 and 2, that is, whether the CS signal is transmitted using the SCHAFENER NSG2070 RF-Generator equipment was tested.

As a result, the cable according to Example and Comparative Example 1 was measured to have a good CS data signal transmission state, while the cable of Comparative Example 2 was measured to be incapable of CS data transmission due to communication interference due to noise.

Test Example 3

Test for electromagnetic compatibility of cables according to Examples and Comparative Examples 1 and 2, using EMC Analyzer E7403A equipment and EMI chamber (shield characteristics: MIL-STD-285, laboratory attenuation characteristics ANSI 63.4) Was measured.

Results of the embodiments of the present invention are as shown in the graph of Figure 5 attached, Comparative Example 1 and Comparative Example 2 are as shown in the graph of Figure 3 and attached, respectively.

As a result, it can be seen that the cable according to the embodiment of the present invention is the most excellent in electromagnetic compatibility as shown in each graph.

That is, as shown in the graph of FIG. 3, in Comparative Example 1, the reference (red) was exceeded at 241.0, 39.7, and 76.1 Mhz frequencies, and as shown in the graph of FIG. 4, in the case of Comparative Example 2, at 187.6 Mhz frequency. It can be seen that the reference (red) is somewhat close to or exceeded, whereas, as shown in the graph of FIG. 5, it can be seen that the example does not exceed the reference (red).

As such, the electromagnetic wave absorbing pellets of the present invention can be widely applied to electronic, semiconductor, optical, and information communication devices that generate electromagnetic waves in addition to communication wires and cables, and thus, excellent electromagnetic shielding and absorption effects can be expected at broadband. In addition, since it can be manufactured in various shapes and forms, and can exhibit excellent electromagnetic wave absorbing ability even in a small volume, it can be applied as an electromagnetic wave absorbing and shielding body of small battery devices and complex devices.

1 is a schematic diagram illustrating a state in which a Cu braid is embedded in a communication cable as a conventional countermeasure against noise caused by electromagnetic waves;

2 is a schematic diagram illustrating a communication cable manufactured using the electromagnetic wave absorbing pellet according to the present invention;

3 is a graph showing the results of experiments on the generation of noise of a communication cable without electromagnetic shielding or absorbers;

4 is a graph showing the experimental results for the generation of noise of a communication cable having a conventional Cu braid;

5 is a graph showing an experimental result for the generation of noise of a communication cable manufactured using the electromagnetic wave absorption pellets according to the present invention;

6 and 7 are electron micrographs showing the shape of the metal flakes used in the electromagnetic wave absorption pellets of the present invention,

<Explanation of symbols for the main parts of the drawings>

30a, 30b: Insulation coating 40: Communication cable

50: power line 60: earth line

80: Cu braid 200: Communication wire or cable

Claims (6)

Processing a spherical metal alloy, which is a raw material, into a plate-shaped metal flake using a grinding mill operated at a constant time and speed together with susbol blending and surfactant addition; In the electromagnetic wave absorption pellet manufacturing method comprising the step of washing the metal flakes with ethyl alcohol or methyl alcohol, water, and drying, Blending and stirring the metal flake powder and polyolefin resin PE or CPE or PET in a ratio of 35 to 95% by weight: 65 to 5% by weight to process the metal paste or the metal compound; Repeatedly mixing the metal paste or the metal compound by passing the mixing roller and sheeting the same; Pulverizing the sheeted product using a pulverizer and processing it into pellets; Electromagnetic wave absorption pellet manufacturing method comprising a. The process according to claim 1, wherein the pellets are passed through a thermocompression roller; Discharging the pellets by the thermocompression roller and discharging them into a sheet for absorbing electromagnetic waves in a sheet form; Applying an adhesive to one surface of the electromagnetic wave absorbing sheet to form an adhesive sheet for absorbing electromagnetic waves; Electromagnetic wave absorption pellet manufacturing method characterized in that it further comprises. The method of claim 1, wherein the raw material of the metal flakes for producing the pellet is Fe-Si alloy, Fe-Si-Cr alloy, amorphous metal (amorphous substance), SDST alloy, high flux (HIGH-FLUXE) , Molypermalloy powder (MMP), Fe-Si, Fe-Si-Cr, Amorphose, Fe-Si-Al-Cr, Carbon coating Iron, Nickel-Zinc Fe Light (Ni-Zn ferrite), manganese-zinc ferrite (Mn-Zn ferrite) powders, characterized in that any one selected from the manufacturing method of the pellet for electromagnetic wave absorption. The pellet for electromagnetic wave absorption manufactured by the manufacturing method of the pellet for electromagnetic wave absorption of Claims 1-3. A communication wire, a voice frequency current transmission cable, a connection of a high frequency device, an internal wiring cable, a power cable, and a control cable in which a communication line, a power line, an earth line, etc. are embedded, for absorbing electromagnetic waves manufactured by the method of claims 1 to 3. Melting pellets, the wires and cables using the electromagnetic wave absorbing pellets, characterized in that the injection molding by insulating coating covering the communication line, power line, earth wire. In a USB cable in which a communication line, a power line, or an earth line is inherent, An electric wave absorber manufactured by the method of claim 2 is attached to a connector and a USB port of a USB cable for noise reduction.

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