KR20150078458A - Electromagnetic Interference Shielding Composition, Method of Preparing Electromagnetic Interference Shielding Composite, And Electromagnetic Interference Shielding Composite Prepared Using Same - Google Patents

Abstract

The present disclosure relates to an ink composition for electromagnetic shielding, which contains a conductive nanomaterial, a magnetic nanoparticle or nanowire, a binder, and a solvent, a manufacturing method of a composite for electromagnetic shielding using the ink composition, and a composite for electromagnetic shielding manufactured by the manufacturing method.

Description

TECHNICAL FIELD [0001] The present invention relates to a composition for shielding electromagnetic waves, a method for producing a composite material for shielding electromagnetic waves using the composition, and a composite material for shielding electromagnetic wave shielding according to the method. Prepared Using Same}

The present invention relates to a composition for shielding electromagnetic waves, a method for producing a composite material for shielding electromagnetic waves using the composition, and a composite material for shielding electromagnetic waves manufactured according to the method.

Recently, electromagnetic wave generation is increasing due to rapid development and mass supply of computers, electronic products, communication devices, etc., and various problems are raised such as the occurrence of noise due to electromagnetic waves in various frequency ranges, have. Particularly, since electronic devices are applied to various safety devices and convenience devices for the safety of drivers and pedestrians in a vehicle, consumers' interest in the functions is maximized. Therefore, in order to reduce the power consumption and high integration , High reliability in various aspects such as suppression of electromagnetic interference between electronic parts due to multifunctionalization, electromagnetic wave shielding, immunity and the like are required.

In order to effectively suppress electromagnetic wave interference between conventional electronic products, it was the best way to enclose the electronic product with a metal housing to shield the electromagnetic wave or construct an expensive electromagnetic wave shielding network. However, in the case of wrapping an electronic product with a metal, there is a problem in that it is disadvantageous in terms of weight saving for improving the fuel consumption due to the weight of the metal itself as well as an expensive mold production cost.

Therefore, studies have been actively carried out to use functional polymer plastics instead of metal as an electromagnetic shielding material for wrapping electronic products. In order to functionalize the polymer plastics, polymer composite materials having electrically conductive or magnetic fillers added thereto . In addition, in general, electromagnetic shielding techniques include reflection shielding using a metal material, absorption shielding using a conductive material, and the like.

In the case of the polymer composite according to the prior art, the magnetic particles are contained in the polymer to secure the absorption shielding property in the low frequency region or to secure the reflection shielding property in the high frequency region by containing the conductive nanomaterial in the polymer. Open Patent Publication No. 2011-53058 discloses a technique of imparting an electromagnetic wave shielding function by using a composite material composed of a polymer and a low melting point metal material.

The polymer composite containing the conductive filler according to the prior art is manufactured by the most common extrusion and injection molding. This is the most economical production method, and it is possible to reduce the weight and manufacturing cost of the electromagnetic shielding material made of a metal material. However, such a conventional polymer composite has a disadvantage in that it is difficult to uniformly disperse and distribute the conductive filler in the polymer during the process of production by extrusion and injection. In order to solve this difficulty of dispersion, various methods such as surface treatment of a conductive filler, addition of a compatibilizer to increase the compatibility between a filler and a polymer have been suggested, but this has been a problem that complicates a manufacturing process and increases manufacturing costs .

In addition, since the polymer composite according to the prior art includes a conductive filler, the electromagnetic shielding function in the low frequency region is limited due to the reflective shielding function due to conductivity, and when cracks or cracks occur in the material, There is a possibility that it becomes a movement route. Therefore, in order to shield a broadband electromagnetic wave, a composite material in which magnetic particles and conductive particles are uniformly used as a housing material of an electronic component should be used. In this case, a cost problem arises.

The present invention develops and applies a low frequency band target electromagnetic wave absorbing material capable of controlling interference caused by electromagnetic waves generated from various control unit devices (MCU, PCU, etc.) of an eco-friendly car, It is an object of the present invention to overcome the durability of a ceramic type such as ferrite and to develop a material which can be lightened at the same time.

Current commercial electromagnetic wave absorbing products are mostly absorbing sheets applicable in a high frequency band, and it is difficult to apply them in a low frequency band as they are. In addition, in the case of a general electromagnetic wave absorber, the magnetic metal filling rate accounts for 80% or more, resulting in a heavy weight of the product and a problem of moldability when applied to parts.

In the present invention, an electromagnetic wave absorbing material optimized for automobiles with the aim of applying a low frequency band is proposed.

In order to solve the above problems, one embodiment provides a composition for shielding electromagnetic interference comprising a conductive nanomaterial, magnetic nanoparticle or nanowire, a binder, and a solvent.

The composition may be an ink-type composition.

The conductive nanomaterial may be a carbon-based nanomaterial such as carbon nanotube (CNT), carbon nanoparticle (CNP), graphene nanoplate (GNP), carbon fiber (CF), carbon black .

The magnetic nanoparticles or nanowires may be nanoparticles or nanowires of soft magnetic metals, such as magnetic metal, for example, iron (Fe), cobalt (Co), nickel (Ni)

As the binder resin, a binder such as a polyester binder, an acrylic binder, a polyvinyl chloride (PVC) binder, a polyurethane binder, a polypropylene binder, a polyethylene binder, an epoxy binder, a polyamide binder, a nylon (PA 6 or PAA6) Mixtures may be used.

As the solvent, a polar solvent such as water, a hydrocarbon halide, an alcoholic solvent, an esteric solvent, a ketonic solvent or an etheric solvent may be used. These solvents may be used alone or in combination of two or more.

The composition may comprise up to about 50 wt.% Conductive nanomaterial, up to about 30 wt.% Magnetic nanoparticle or nanowire, and a balance of binder, based on the solids content in the composition, Lt; RTI ID = 0.0 >% < / RTI >

The composition may be coated or printed on a substrate for imparting electromagnetic wave shielding capability and made of a composite material for shielding electromagnetic waves.

The substrate may be any material such as metal or plastic resin.

Accordingly, in another embodiment, there is provided a method of manufacturing a composite material for shielding electromagnetic interference, which comprises coating or printing the ink composition for shielding electromagnetic waves on a substrate.

The substrate and the ink composition for shielding electromagnetic waves are as described above.

The coating or printing may be coating or printing using spray coating, coating with a doctor blade, physical vapor deposition (PVD), chemical vapor deposition (CVD), or the like.

The coating or printing includes coating or printing through a mesh screen.

When the ink composition is coated or printed on the substrate through the mesh-type screen, the ink composition for shielding electromagnetic waves may be coated or printed on the substrate between the grids of the screen.

The above manufacturing method can provide an electromagnetic wave shielding composite material which can easily shield an electromagnetic wave of a desired frequency band by adjusting the lattice size of the mesh screen.

Accordingly, in another embodiment, there is provided a composite material for shielding electromagnetic interference, which is produced according to the above manufacturing method.

The electromagnetic wave shielding composite material is a composite material in which the electromagnetic wave shielding composition forms a mesh on a substrate.

The substrate may be any material such as metal or plastic resin.

According to this embodiment, it is possible to provide an electromagnetic shielding composite material which can be lightweight and improved in corrosion resistance compared to a general metal material.

The electromagnetic wave shielding composite material can improve electromagnetic wave absorption characteristics in a low frequency band and can also control shielding effect in a specific frequency band.

Since the electromagnetic wave shielding composite material is made of a composite material of a conductive nanomaterial and magnetic nanoparticles or nanowires, it is also possible to retain strength characteristics as in the case of using conventional glass fibers.

Furthermore, the electromagnetic wave shielding composite material can improve the control characteristics of electromagnetic waves with respect to the thickness by the thin film mesh coating technique, and can be easily manufactured even in a general sheet type, thereby enlarging the application area for automobile electric parts and the like.

FIG. 1 is a schematic view of a housing for electromagnetic shielding with improved shielding ability of electromagnetic waves coated with an ink composition for shielding electromagnetic waves through a mesh screen according to an embodiment of the present invention in a metallic housing such as a conventional MCU or ACU.
FIG. 2 is a schematic view of a thin film electromagnetic shielding sheet in which an electromagnetic shielding ink composition of the present invention is coated with a general plastic-containing housing material through a mesh screen according to an embodiment of the present invention.
3 is a graph schematically showing the degree of reduction (shielding effect) of electromagnetic noise in the entire frequency region compared to before coating of the composition when the ink composition for electromagnetic wave shielding according to the embodiment of the present invention is coated on a general plastic substrate to be.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

In one embodiment of the present invention, there is provided an ink composition for shielding electromagnetic interference comprising a conductive nanomaterial, a magnetic nanoparticle or nanowire, a binder, and a solvent.

Examples of the conductive nanomaterial include carbon nanomaterials such as carbon nanotubes (CNTs), carbon nanoparticles (CNPs), graphene nanoplates (GNPs), carbon fibers (CFs), carbon blacks And the present invention is not limited thereto.

The conductive nanomaterial may be present in an amount of up to about 50% by weight, for example from about 10% by weight to about 45% by weight, for example from about 20% by weight to about 40% by weight, based on the solids content of the ink composition for shielding electromagnetic waves Can be used.

By including the conductive nanomaterial in the above range, the electromagnetic wave shielding ink composition according to the above embodiment can achieve electromagnetic wave shielding ability by reflecting electromagnetic waves in a high frequency or low frequency range. If the content of the conductive nanomaterial exceeds 50 wt%, molding problems may arise. If the content of the conductive nanomaterial is less than 10 wt%, the same effect as that of the commercial absorbent material having the insulating property may occur.

The magnetic nanoparticles or nanowires may be nanoparticles or nanowires of a soft magnetic metal such as a magnetic metal, for example, iron (Fe), cobalt (Co), nickel (Ni) It does not.

The magnetic nanoparticles or the magnetic nanowires may be used in an amount of about 35% by weight or less, for example, about 10% by weight to about 35% by weight, for example, about 15% by weight to about 35% by weight based on the solid content of the electromagnetic wave- 30% by weight.

When the magnetic nanoparticles or the magnetic nanowires are contained in the ink composition within the above range, the composition can efficiently absorb electromagnetic waves in the low frequency range. When the magnetic nanoparticles or the magnetic nanowires are contained in an amount of more than 35% by weight, a molding problem may occur. When the magnetic nanoparticles or the magnetic nanowires are used in an amount of less than 15% by weight, have.

As the binder resin, a binder resin usable in an electromagnetic wave shielding composition can be used without limitation. Examples of the binder resin include polyester binders, acrylic binders, polyvinyl chloride (PVC) binders, polyurethane binders, polypropylene binders, polyethylene binders, Epoxy binders, polyamide binders, nylon (PA 6 or PAA 6, etc.) binders, and the like.

When the binder is used, dispersion stability can be maintained even when the conductive material and the magnetic nanowires or the magnetic nanowires are used in a somewhat large amount.

The amount of the binder resin to be used is about 35% by weight or less, for example about 10% by weight to about 35% by weight, for example about 15% by weight to about 30% by weight based on the solid content of the ink composition .

When the binder resin is used within the above range, electromagnetic shielding ability, dispersibility of the conductive nanoparticles and the magnetic nanoparticles or nanowires, storage stability, and spray coatability can all be satisfied.

The solvent is used in an electromagnetic shielding composition and can be used without limitation as long as it is compatible with the conductive material, the magnetic material, and the binder resin. For example, the solvent may be water, a hydrocarbon halide solvent, an alcohol solvent, an ester solvent, a ketone solvent, an ether solvent or the like, and these solvents may be used singly or in combination of two or more.

Examples of the alcohol solvent include polyhydric alcohol solvents such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, glycerol and terpineol. Examples of the ether solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, Ethylene glycol monobutyl ether, propylene glycol monomethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, dipropylene glycol methyl ether and the like. Examples of the ketone solvent include n-methylpiperazine Propylenecarbonate, ethylene carbonate, dimethylformamide, and the like can be used alone or in admixture of two or more.

The solvent is used to dilute the electromagnetic wave shielding composition to a concentration suitable for coating or printing by a suitable method and can be used in an arbitrary amount so long as the composition can be diluted to an appropriate concentration, . In particular, since the solvent is not evaporated or volatilized in the finally produced electromagnetic shielding composite material, it is possible to provide an appropriate concentration for the above-mentioned coating or printing, and also to provide a content It may be included in an arbitrary content.

The ink composition may be coated or printed on a substrate for imparting electromagnetic wave shielding performance and made of a composite material for shielding electromagnetic waves.

For example, the electromagnetic wave shielding composite material can be produced by coating or printing the ink composition on a substrate made of any material such as metal or plastic resin. In this case, the coating may be a coating or printing using spray coating, coating with a doctor blade, physical vapor deposition (PVD), or chemical vapor deposition (CVD). At this time, the coating or printing can also be carried out using a coating or printing method, for example, through a mesh screen.

When the ink composition is coated or printed on a substrate through a mesh-type screen, the ink composition for shielding electromagnetic waves may be coated or printed on the substrate through lattices of the mesh-type screen. Therefore, by controlling the mesh size of the mesh screen, it is possible to easily provide a composite material for shielding electromagnetic waves that can shield electromagnetic waves of a desired frequency band. For example, when the wavelength of the electromagnetic wave to be shielded is?, The electromagnetic wave having the wavelength can be easily shielded by adjusting the inter-grid distance to? / 4 or less.

When the substrate is a metal substrate, the metal substrate may be an aluminum substrate.

FIG. 1 is a cross-sectional view of an ink composition for electromagnetic shielding according to an embodiment of the present invention, which is printed on a MCU or ACU housing of a conventional metal material housing through a mesh screen, Shielding housing having improved shielding ability.

In the case of a conventional aluminum-made housing, high-frequency shielding using electromagnetic shielding of the electromagnetic wave was possible. On the other hand, by coating the ink composition of the present invention through a mesh screen, electromagnetic wave reflection shielding ability by the conductive nanoparticles is further increased , Electromagnetic waves in the low-frequency region using the electromagnetic nanoparticles or nano-particles and the electromagnetic wave absorption shielding can be effectively shielded.

On the other hand, when the composition is coated through a mesh screen and the inter-grid distance of the mesh screen is controlled to be equal to or smaller than 1/4 of the electromagnetic wave wavelength (?) To be shielded, can do. In addition, since the coating can be printed on a conventional material in the form of a thin film, the electromagnetic wave shielding function can be improved while maintaining weight reduction of the material.

2 schematically shows a thin film electromagnetic wave shielding sheet obtained by placing a mesh screen on a general plastic-containing housing material and coating the ink composition for electromagnetic wave shielding of the present invention therewith. The electromagnetic wave shielding sheet thus manufactured can be easily used as an electromagnetic shielding material by adhering it to a desired position. Alternatively, the housing may be manufactured from the material. The plastic material coated with the electromagnetic wave shielding ink composition of the present invention has the ability to shield electromagnetic waves by the conductive material in the composition, It is possible to have all of electromagnetic wave absorption shielding ability by the magnetic material in the composition. In addition, the composition in which the composition is coated in the form of a mesh in the plastic material can maintain the lighter weight of the material, and can exhibit an electromagnetic shielding effect that is lighter than the conventional metal housing.

3 is a graph showing the degree of reduction of electromagnetic noise in the whole frequency region, that is, the degree of electromagnetic shielding, compared to the material before coating the composition, when the electromagnetic wave shielding composition according to the present invention is entirely coated on a thin film of a general plastic material Fig. 3, when the composition for electromagnetic shielding according to the present invention is entirely coated on a sheet to prepare an electromagnetic wave shielding sheet, the electromagnetic wave shielding sheet can be produced in a high frequency range (300 MHz to 1 GHz) An electromagnetic wave shielding effect of about 40 dB can be achieved and an electromagnetic wave shielding effect of about 30 dB can be achieved in the low frequency range (10 MHz to 300 MHz). When the composition of the present invention having the electromagnetic shielding effect is coated on a housing or a general sheet-like thin film through a mesh screen, it can be understood that the electromagnetic wave shielding effect as described above can be achieved without significantly increasing the weight of the existing material have.

Hereinafter, the present invention will be described in detail by way of examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Example

( Example  One)

40 wt% of carbon black (CB) as a conductive nano material, 40 wt% of sandust (FeSiAl alloy) nanoparticles as magnetic nanoparticles, and 30 wt% of a polyurethane binder were added to toluene and stirred to obtain an electromagnetic wave shielding ink composition . The amount of the toluene solvent may be appropriately adjusted so that the composition can be prepared into a liquid having a low viscosity so as to be suitable for spray coating or the like.

The composition was spray coated onto a plastic mock-up housing surface through a mesh screen. The inter-grid interval of the mesh screen can be appropriately adjusted according to a frequency band to be controlled.

The entire surface of the housing is coated with the electromagnetic wave shielding ink composition through a mesh screen in the same manner as described above to obtain a housing having the electromagnetic shielding ability as shown in Fig.

( Example  2)

The electromagnetic wave shielding composition prepared in Example 1 was spray-coated on a sheet surface of a general plastic material not containing conductive nano-particles or magnetic nano-particles through a mesh screen in the same manner as in Example 1, A thin film sheet for shielding electromagnetic waves is obtained. The thin film sheet for shielding electromagnetic waves thus obtained can be easily adhered to a desired position to obtain an electromagnetic wave shielding effect, or a housing for electromagnetic wave shielding or the like can be manufactured using the thin film sheet.

( Test Example  One)

The electromagnetic shielding ratio was measured according to the ASTM D4935-10 standard for the sheet of the plastic material used in Example 2 and the sheet on which the electromagnetic wave shielding ink composition prepared in Example 1 was entirely coated on the sheet surface, 3.

As can be seen from Fig. 3, the sheet coated with the ink composition for shielding electromagnetic wave according to the present invention has an electromagnetic noise of 30 dB or more in the entire frequency range (10 MHz to 1 GHz) As shown in Fig. Accordingly, by coating the ink composition for electromagnetic wave shielding according to the present invention through a mesh screen having a mesh-to-mesh spacing adjusted according to the wavelength of an electromagnetic wave to be shielded, it has an electromagnetic shielding effect as described above, It is possible to manufacture a material having electromagnetic shielding ability that does not increase the weight.

INDUSTRIAL APPLICABILITY As described above, the composition for shielding electromagnetic waves according to the present invention can be used for electromagnetic shielding with improved shielding ability of electromagnetic waves in the whole frequency range of high frequency band and low frequency band due to both reflection shielding due to conductive material and absorption shielding by magnetic material A composite material can be provided. Further, by coating the electromagnetic wave shielding composition through a mesh screen, it is possible to easily adjust the frequency region to be shielded while maintaining weight reduction of the material. Further, since the composition for shielding electromagnetic waves is manufactured in an ink type, it can be easily applied where necessary by coating or printing. Also, by using the conductive material and the magnetic material together, the composition can be improved in strength characteristics of the electromagnetic wave shielding composite material.

The present invention is not limited to the above-described embodiment, and various modifications and changes may be made. It will be appreciated that such modifications and variations may be made in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the above-described embodiments are to be considered in all respects as illustrative and not restrictive.

Claims (14)

1. An electromagnetic wave shielding ink composition comprising a conductive nanomaterial, magnetic nanoparticle or nanowire, a binder, and a solvent. The conductive nanomaterial according to claim 1, wherein the conductive nanomaterial is a carbon nanotube (CNT), a carbon nanoparticle (CNP), a graphene nanoplate (GNP), a carbon fiber (CF), a carbon black (CB) Wherein the composition is a carbon-based nanomaterial. The composition of claim 1, wherein the magnetic nanoparticles or nanowires are nanoparticles or nanowires of iron (Fe), cobalt (Co), nickel (Ni), or a mixture of two or more thereof. The method of claim 1, wherein the binder resin is selected from the group consisting of polyester binders, acrylic binders, polyvinyl chloride (PVC) binders, polyurethane binders, polypropylene binders, polyethylene binders, epoxy binders, polyamide binders, nylon (PA 6 or PAA 6, A binder, or a mixture of two or more thereof. The composition of claim 1, wherein the solvent is water, a hydrocarbon halide, an alcoholic solvent, an esteric solvent, a ketonic solvent, an etheric solvent, or a mixture of two or more thereof. The composition of claim 1, wherein the composition comprises no more than 50% by weight of conductive nanomaterial, no more than 35% by weight of magnetic nanoparticles or nanowires, and a residual amount of binder, based on the solids content in the composition. The composition of claim 6, wherein the composition comprises 10 wt% to 45 wt% of conductive nanomaterial, 10 wt% to 35 wt% of magnetic nanoparticle or nanowire, 10 wt% to 35 wt% Of a binder. A method for manufacturing a composite material for shielding electromagnetic interference, which comprises coating or printing the electromagnetic wave shielding ink composition according to claim 1 on a substrate. 9. The method of claim 8, wherein the substrate is a metal or plastic substrate. The method of claim 8, wherein the coating or printing is a coating or printing by spray coating, coating with a doctor blade, physical vapor deposition (PVD), or chemical vapor deposition (CVD). 11. The method of claim 10, wherein the coating or printing comprises coating or printing through a mesh screen. A composite material for shielding electromagnetic interference, wherein the electromagnetic wave shielding ink composition of claim 1 is coated on a substrate in a mesh form. The composite material for shielding electromagnetic interference according to claim 12, wherein the substrate is a metal or plastic substrate. 14. The electromagnetic wave shielding composite material according to claim 13, wherein the metal is aluminum.

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