WO2020204361A1 - Composite magnetic shielding sheet having excellent functions of shielding and absorbing electromagnetic waves and manufacturing method for magnetic sheet - Google Patents

Abstract

The present invention relates to a composite magnetic shielding sheet capable of shielding and absorbing electromagnetic waves that may cause harmful effects on the human body or the malfunction of other electronic equipment and promptly dissipating heat generated in electronic devices and to a manufacturing method for a magnetic sheet. The present invention relates to a composite electromagnetic wave shielding sheet and a manufacturing method for a magnetic sheet having excellent electromagnetic wave shielding and absorbing characteristics and heat dissipating characteristics, wherein the composite electromagnetic wave shielding sheet comprises: a magnetic sheet comprising a nanocrystallized, plate-like structured amorphous alloy powder; a conductive adhesive unit provided on a surface of the magnetic sheet; and a soft magnetic alloy thin strip attached to a surface of the magnetic sheet via an adhesive, and wherein the method comprises: a heat treatment step of heat-treating an amorphous alloy ribbon at a temperature lower than the crystallization temperature thereof; a pulverization step of pulverizing the amorphous alloy ribbon to produce an amorphous alloy flake powder having a length of 100 μm or less; and a molding step of producing a magnetic sheet from the amorphous alloy flake powder and a binder resin.

Description

Composite magnetic shielding sheet excellent in shielding and absorbing electromagnetic waves and manufacturing method of magnetic sheet

The present invention relates to a composite magnetic shielding sheet having a function of shielding and absorbing electromagnetic waves, and more particularly, it is possible to shield and absorb electromagnetic waves that may cause harmful effects on the human body or malfunction of other electronic equipment. It relates to a composite magnetic shielding sheet capable of quickly discharging generated heat. In addition, the present invention relates to a method of manufacturing a magnetic sheet having excellent shielding and absorption and heat dissipation properties of electromagnetic waves capable of shielding and absorbing electromagnetic waves, as well as rapidly discharging heat generated from electronic devices.

Electromagnetic waves refer to electric and magnetic wavelengths including electric and magnetic fields generated by electric products or electronic products. Such electromagnetic waves may cause malfunctions of electrical and electronic devices. This is because electrical and electronic devices are recently mounted with high-density, high-integration circuit parts, etc. due to their small size, light weight, and thinness, causing radio wave disturbances between these circuit parts. .

In addition, electromagnetic waves affect not only the malfunction of electrical and electronic components, but also the human body. When the electromagnetic waves reach the human body, they may raise body temperature in whole or in part or stimulate the nervous system by electric currents induced in the body.

A coating layer for shielding electromagnetic waves is formed on a surface of an electronic component mounted in an electronic device as a method for blocking electromagnetic waves that have a harmful effect on such electronic products or human body.

Specifically, electromagnetic interference (EMI) and electromagnetic compatibility (Electro-Magnetic Interference) due to miniaturization, high-performance, high-integration, high-frequency, and broadband electronic components such as smart cars, electric vehicles, mobile phones, laptops, and iPads Compatibility: The development of electromagnetic wave shielding materials having a shielding function is required.

In accordance with this situation, Korean Patent Registration No. 10-1803828 (name of the invention: electromagnetic wave shielding sheet having flexural properties and a method for manufacturing the same) was invented, but it is a combination of aluminum (Al) as a conductor and Sendust as an absorber. It is a product having a thickness of less than 0.3mm manufactured, and has a very good shielding ability of 80dB or more, but has a disadvantage that the effective permeability drops sharply in the 20MHz band or more.

In addition, in recent years, a technique of using a magnetic sheet as a shielding sheet for electromagnetic waves has been studied, but it has a disadvantage that the shielding rate and absorption rate are inferior in the high frequency band.

In addition, in recent years, a technology for applying an amorphous alloy ribbon having high permeability to a shielding sheet for shielding electromagnetic waves and absorbing has been studied. However, in order to manufacture a shielding sheet based on an amorphous alloy ribbon, the ribbon must be cut, crushed and flake treated, but the mechanical properties of the amorphous alloy are compared to the existing crystalline alloys such as Sendust (FeSiAl alloy) and FeSiCr alloy. Since it retains strength and toughness several times higher than that, there is a problem in that it takes several times as long as the process time of the existing crystalline alloy, especially the process time of the grinding and flake process.

In addition, the amorphous alloy has a problem in that a significant amount of impurities are introduced into the powder during processing under the same conditions as the crystalline alloy, since the material in the grinding device and the ball is worn.

As such, amorphous alloys are difficult to apply to shielding sheets because excellent soft magnetic properties (e.g., effective permeability, coercivity, iron loss, etc.) deteriorate significantly during processing, and accordingly, commercialization of shielding sheets as amorphous flake powder It is hardly being done.

[Prior technical literature]

[Patent Literature]

Patent Document 1: Korean Patent Registration No. 10-1803828 (announced on Dec. 4, 2017)

Patent Document 2: Republic of Korea Patent Publication No. 10-2018-0129721 (published on Dec. 5, 2018)

Patent Document 3: Korean Patent Application Publication No. 10-2007-0010428 (published on January 24, 2007)

Patent Document 4: Korean Patent Application Publication No. 10-2013-0096560 (published on August 30, 2013)

It is an object of the present invention to provide a sheet-like plate-like structure with absorption capacity fine-grained amorphous and nanocrystalline metal alloy flakes to effectively absorb and shield electromagnetic waves even at a thin thickness, instead of a non-magnetic conductive metal ribbon. It is to provide a composite magnetic shielding sheet that can improve the absorption rate by providing an alloy ribbon of a soft magnetic material.

In addition, it is an object of the present invention to easily powder the amorphous alloy ribbon through surface cracks or partial rearrangement of over-employed elements while maintaining the amorphous phase of the amorphous alloy ribbon. The objective is to provide a method of manufacturing a magnetic sheet having excellent electromagnetic wave shielding and absorption and heat dissipation properties that can effectively absorb and shield electromagnetic waves even at a thin thickness by providing fine-grained amorphous alloy flakes in the form of a structure.

In order to achieve the above-described object of the present invention, in one embodiment of the present invention (Examples 1 to 4), a magnetic sheet containing amorphous alloy powder of a plate-like structure subjected to nanocrystallization, and a magnetic sheet provided on the surface of the magnetic sheet It provides a composite electromagnetic wave shielding sheet comprising a conductive bonding means, and a soft magnetic alloy foil attached to the surface of the magnetic sheet through the adhesive.

In addition, in another embodiment of the present invention (Examples 5 to 9), a heat treatment step of heat-treating the amorphous alloy ribbon at a temperature below the crystallization temperature, and pulverizing the amorphous alloy ribbon to produce amorphous alloy flakes having an average particle diameter of 100 μm or less It provides a method of manufacturing a magnetic sheet excellent in shielding and absorption of electromagnetic waves and heat dissipation properties, including a pulverizing step of performing the amorphous alloy flake and a forming step of generating a magnetic sheet from the binder resin.

The composite magnetic shielding sheet according to the present invention provides a shielding rate of 85 dB or more in a frequency band of 100 kHz to 10 GHz, an absorption rate of 50% or more in a frequency band of 100 MHz to 10 GHz, and a thermal conductivity of 20 W/m· in the horizontal direction. The above thermal conductivity can be provided.

In addition, since the composite magnetic shielding sheet according to the present invention can effectively absorb and shield electromagnetic waves even in a thin thickness of 0.4 mm or less, it can be applied to various products such as the exterior of an electric control box with a lot of electromagnetic waves, mobile phones, and electronic components of smart cars. have.

In addition, when the magnetic material sheet including amorphous and nanocrystalline metal alloy flakes is used alone, the composite magnetic material shielding sheet according to the present invention can solve the problem of having a low shielding rate and absorption rate for electromagnetic waves in a high frequency band.

In addition, according to the method of manufacturing a magnetic material sheet of the present invention, the amorphous alloy ribbon is heat-treated at a temperature lower than the crystallization temperature to maintain the amorphous phase, so that the surface crack or the partial rearrangement of the over-solidified elements can be proceeded. The amorphous alloy ribbon can be easily powdered.

In addition, the magnetic sheet manufactured through the manufacturing method according to the present invention has a shielding rate of 30 dB or more, an absorption rate of 5% or more, a thermal conductivity of 1.0 W/m· or more in a vertical direction, and a thermal conductivity in the frequency band of 1 MHz to 10 GHz. Since is more than 4.0W/m· in the horizontal direction, it exhibits far superior electromagnetic wave shielding and absorption functions and heat dissipation properties than the shielding sheets of Sendust and FeSiCr alloys used in the past.

In addition, since the magnetic sheet manufactured through the manufacturing method according to the present invention can effectively absorb and shield electromagnetic waves even in a thin thickness of 0.3 mm or less, the exterior of an electric control box with a lot of electromagnetic waves, mobile phones, electronic components of smart cars, etc. Can be applied to products.

1 is a schematic diagram for explaining the configuration of a composite magnetic shielding sheet according to the present invention.

Figure 2 is a flow chart for explaining the manufacturing method of the composite magnetic shielding sheet according to the present invention.

3 and 4 are SEM photographs showing the microstructure of the amorphous flake alloy powder used in Example 1.

5 is a graph showing the shielding rate for the composite magnetic shielding sheets manufactured through Examples 1 to 4 and Comparative Examples 1 and 2.

6 is a graph showing the absorption rate for the composite magnetic shielding sheet prepared through Examples 1 to 4 and Comparative Examples 1 and 2.

7 is a flowchart illustrating a method of manufacturing a magnetic sheet according to an embodiment of the present invention.

8 is a flow chart for explaining a method of manufacturing a magnetic sheet according to another embodiment of the present invention.

9 is a graph showing the shielding rate for magnetic sheet prepared through Examples 5 to 9.

10 is a graph showing a shielding rate for magnetic sheets manufactured through Comparative Examples 3 to 6.

11 is a graph showing the absorption rate of the magnetic sheet prepared through Examples 5 to 9.

12 is a graph showing the absorption rate of the magnetic sheet prepared through Comparative Examples 3 to 6.

The following describes a composite magnetic shielding sheet (hereinafter, abbreviated as a'composite magnetic shielding sheet') excellent in shielding and absorbing electromagnetic waves in Examples 1 to 4 of the present invention. In addition, Examples 5 to 4 of the present invention In 9, a method of manufacturing a magnetic sheet (hereinafter, abbreviated as'magnetic sheet') having excellent shielding and absorption of electromagnetic waves and heat dissipation properties will be described.

First, the following describes the composite magnetic shielding sheet.

1 is a schematic diagram for explaining the configuration of a composite magnetic shielding sheet according to the present invention. Referring to FIG. 1, the composite magnetic material shielding sheet according to the present invention includes a magnetic material sheet 10 provided with amorphous and nanocrystalline metal alloy flakes in a plate-like structure having absorption ability, and provided on the surface of the magnetic material sheet 10. It includes a conductive bonding means 20, and a soft magnetic alloy foil 30 attached by the adhesive. At this time, the composite magnetic shielding sheet is 0.4 mm or less, preferably 0.15 mm or less so that it can provide sufficient shielding and absorption functions for electromagnetic waves while being applied to various products such as the exterior of an electric control box that generates many electromagnetic waves, mobile phones, and electronic components of smart cars. It is preferably formed to a thickness of 0.4mm.

Referring to Figure 1, the composite magnetic material shielding sheet according to the present invention includes a magnetic material sheet (10). The magnetic sheet 10 is a sheet containing alloy powder having a plate-like structure therein, and further includes a binder resin. At this time, the alloy powder having a plate-like structure may be an amorphous alloy powder of a heat-treated plate-like structure, or an alloy powder that has been heat-treated and nanocrystallized into a plate-like structure, or both.

Specifically, the magnetic sheet 10 may be configured to include 100 parts by weight of an alloy powder having a plate-like structure and 6 to 10 parts by weight of a binder resin. At this time, if the content of the binder resin is less than 6 parts by weight, the binding strength of the binder resin is weak, and if the content of the binder resin exceeds 10 parts by weight, the shielding rate and the absorption rate of the magnetic sheet 10 decrease due to an excessive amount of the binder resin. do.

The heat-treated amorphous alloy powder of the plate-like structure and the alloy powder that has been heat-treated and nanocrystallized into a plate-like structure are all produced by heat-treating the amorphous alloy powder, and the amorphous alloy whose internal structure is capable of sintering nanocrystallization is nanocrystallized into a plate-like structure. An amorphous alloy that becomes an alloy powder and the internal structure is not nanocrystallized becomes an amorphous alloy powder of a heat-treated plate-like structure. In this case, the heat treatment is performed in order to remove internal stress generated during milling of the alloy powder and to improve soft magnetic properties.

The magnetic sheet 10 is formed to have a thickness of 0.1 mm to 0.3 mm. At this time, if the magnetic sheet 10 is formed with a thickness of 0.1 mm or less, it becomes difficult to provide sufficient electromagnetic wave absorption, and when the magnetic sheet 10 is formed with a thickness of more than 0.3 mm, the bendability of the composite magnetic shielding sheet is lowered. Can cause damage.

The magnetic sheet 10 is formed to have a density of 3.5 to 4.5 g/cm ² . At this time, when the density of the magnetic sheet 10 is formed to be less than 3.5 g/cm ² , the effective permeability is lowered to 85 or less in the frequency band of 10 MHz, and when the density is formed to exceed 4.5 g/cm ² , the workability of hot forming There is a problem of falling.

The amorphous alloy powder of the plate-like structure preferably has an aspect ratio of 5 to 50 and an average thickness of 0.5 to 15 μm. This is because when the aspect ratio is 5 or less, the filling density is lowered, and when the aspect ratio exceeds 50, productivity is lacking. In addition, when the average thickness exceeds 15 μm, the effective permeability decreases due to the effect of the diamagnetic field in the high-frequency band, and when the average thickness is 0.5 μm or less, productivity and workability are deteriorated.

As the alloy powder having a plate-like structure, it is preferable to use an amorphous soft magnetic alloy powder containing iron or cobalt. Specifically, Fe-Si-B-based, Fe-Nb-B-based, Fe-Si-CP-based, and the like may be used as the iron-based, and Co-Fe-B-based and the like may be used as the cobalt-based.

Specifically, amorphous alloys such as FeSiBNbCu-based, FeSiCPCu-based, and FeNbB-based among the heat-treated plate-like amorphous alloy powders are prepared by performing heat treatment in a reducing atmosphere for 30 to 100 minutes at a temperature 10 to 50°C higher than the crystallization initiation temperature. At this time, as the FeSiBNbCu system, Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ , Fe ₇₄ Si ₁₃ B ₉ Nb _5, etc. may be used, and as the FeSiCPCu system, Fe ₇₈ Si ₃ C ₆ B ₅ P ₉ , Fe ₈₅ Si ₂ B ₅ P ₄ Cu ₁ or the like may be used, and Fe ₇₂ B ₁₄ Si ₁₀ Nb ₅ may be used as the FeNbB system.

In addition, amorphous alloys such as FeSiB-based or CoFeB-based alloy powders that are heat treated above the crystallization initiation temperature and are not nanocrystallized into a plate-like structure are manufactured by performing heat treatment in a reducing atmosphere for 30 to 100 minutes at a temperature 20 to 50°C lower than the crystallization temperature. do. At this time, FeSiB to step may be used such as Fe ₇₈ Si ₁₃ B _9, CoFeB to step may be used such as _{Co 70 Fe 5 Si 15 B 10} .

The binder resin is disposed so as to surround the outside of the alloy powder having a plate-like structure to provide insulation and a role of a binder, and a thermoplastic resin solution such as polyimide, PVA, urethane-based, or styrene-butadiene rubber (SBR) may be used. For example, as the binder resin, a binder resin in which 18% by weight of SBR solid powder and a small amount of a curing agent and a crosslinking agent are mixed may be used.

The thermoplastic resin is useful for sheet compounding because the resin melts in the heat applied during lamination, and it becomes easy to attach the soft magnetic alloy foil 30 to one side of the magnetic sheet 10 without using a separate adhesive. . As such a thermoplastic resin, any one selected from the group consisting of polyimide resins, acrylic resins, and urethane resins may be used.

Referring to Figure 1, the composite magnetic material shielding sheet according to the present invention includes a conductive adhesive means (20).

The conductive adhesive means 20 is provided on the surface of the magnetic sheet 10 to provide an adhesive force so that the soft magnetic alloy foil 30 is attached to the magnetic sheet 10, the magnetic sheet 10 and the soft magnetic alloy foil It is located between (30).

This conductive bonding means 20 acts to improve the interlayer electrical conductivity between the magnetic sheet 10 and the soft magnetic alloy thin ribbon 30, thereby improving the vertical and horizontal thermal conductivity.

The conductive adhesive means 20 may be a conductive adhesive or a conductive double-sided tape, but is not limited thereto.

Silver conductive epoxy may be mainly used as the conductive adhesive, and a tape made of a conductive filler such as black carbon and graphite powder may be used as the conductive double-sided tape.

Referring to Figure 1, the composite magnetic material shielding sheet according to the present invention includes a soft magnetic alloy foil.

The soft magnetic alloy foil is attached to one side of the magnetic sheet 10 in a composite manner in order to utilize the properties of the soft magnetic material in the concept of magnetization, and is preferably formed to a thickness of 0.05 mm to 0.2 mm, but is not limited thereto. Does not. At this time, since the alloy thin ribbon, which is a soft magnetic material, is magnetized by an external magnetic field to efficiently absorb electromagnetic waves, the absorption rate of electromagnetic waves up to the high frequency band is improved.

On the other hand, if a metal foil of a non-magnetic material having excellent conductivity is used instead of a soft magnetic alloy foil, there is a disadvantage that even if the electromagnetic wave is reflected, absorption is hardly caused inside the shielding material.

As the soft magnetic alloy foil, an amorphous or crystalline alloy foil including iron or cobalt may be used. Specifically, as the soft magnetic amorphous alloy foil, Fe-Si-B system, Fe-Si-B-Nb-Cu system, Co-Fe-B system, Fe-Nb-B system, etc. may be used. As the alloy foil, Fe-Si-based, Fe-Ni-based, Fe-Ni-Mo-based, etc. may be used.

On the other hand, if copper (Cu) or aluminum (Al), which is a conductive material with a metal foil, is adhered to the magnetic sheet 10, a shielding rate of 80dB or more can be displayed, but since absorption and removal of electromagnetic waves hardly occur, the use of a conductive metal foil There is a disadvantage that the ability to absorb electromagnetic waves per total weight is poor.

As described above, the present invention provides an effect of significantly improving the shielding rate and significantly improving the absorption rate compared to the case of using a non-magnetic metal foil using a soft magnetic alloy foil.

Figure 2 is a flow chart for explaining the manufacturing method of the composite magnetic shielding sheet according to the present invention.

Referring to FIG. 2, the method of manufacturing a composite magnetic shielding sheet according to the present invention includes a first heat treatment step (S100) of heat-treating an amorphous alloy below a crystallization initiation temperature, and an alloy powder having a plate structure by pulverizing the heat-treated alloy. The pulverization step (S200) to generate the, the secondary heat treatment step (S250) of heat treatment to remove the internal stress of the alloy powder having a plate-like structure and improve the soft magnetic properties, the alloy powder having a plate-like structure that has passed the secondary heat treatment A slurry generation step (S300) of generating the contained slurry, a magnetic sheet manufacturing step (S400) of producing a magnetic sheet 10 from the slurry, and a conductive adhesive means 20 on one surface of the magnetic sheet 10 It includes a bonding means forming step (S500), and an attaching step (S600) of attaching the soft magnetic alloy thin ribbon 30 to the conductive bonding means 20.

First, the first heat treatment step (S100) is a step of heat-treating the amorphous alloy at a temperature below the crystallization initiation temperature. The amorphous alloy is easily pulverized by partially rearranging surface cracks or over-solvented elements while maintaining the amorphous phase. Let the flake progress.

Specifically, in the first heat treatment step (S100), it is preferable to perform the heat treatment for 30 to 100 minutes at a temperature of a reducing atmosphere 20 to 150 ℃ lower than the crystallization initiation temperature of the amorphous alloy.

At this time, if the heat treatment temperature is between a temperature 20°C lower than the crystallization start temperature (ie, the crystallization start temperature to the crystallization start temperature -20°C), there is a concern that some crystallization may occur. And if the heat treatment temperature is lower than 150℃ based on the crystallization initiation temperature, the milling time exceeds 10 hours when manufacturing amorphous alloy powder having a plate-like structure with an average particle diameter of 100㎛ or less. Incorporation of impurities may increase. In addition, if the heat treatment time is less than 30 minutes, sufficient heat treatment is not performed, and if the heat treatment time exceeds 100 minutes, the economy is poor.

Then, the pulverizing step (S200) is a step of pulverizing the amorphous alloy heat-treated through the first heat treatment step (S100) to generate an amorphous alloy powder having a plate-like structure having an average particle diameter of 100 µm or less. It can be configured to include.

It is preferable that the plate-like amorphous alloy powder produced through the crushing step (S200) has a thickness of 0.5 μm to 15 μm, an average particle diameter of 10 μm to 100 μm, and an average aspect ratio (length/thickness) of 5 to 50. Do. At this time, if the average particle diameter is less than 10 μm, it takes excessive milling time, and if it exceeds 100 μm, there may be a problem that the surface roughness is poor during sheet manufacturing. And if the average aspect ratio is less than 5, the specific surface area of the amorphous alloy powder having a plate-like structure is small, so the molding density is lowered. If it exceeds 50, the average particle diameter of the amorphous alloy powder having a plate-like structure exceeds 100 μm and becomes coarse. A problem of poor surface roughness may occur.

In the grinding process constituting the grinding step (S200) according to the present invention, the amorphous alloy heat-treated through the first heat treatment step (S100) is ground manually or by equipment such as a grinder.

In the plate-like texture process constituting the crushing step (S200) according to the present invention, the alloy powder pulverized through the crushing process is finely pulverized using a mill such as a ball mill or an attrition mill, and the plate structure To produce an alloy powder having

More specifically, it is preferable that the milling speed of a mill, such as an attention mill, is 300 to 600 rpm in the plate-like texture process. At this time, when the milling speed is less than 300 rpm, sufficient pulverization does not occur, and when the milling speed exceeds 600 rpm, a problem of increased wear in the device and the ball may occur due to the application of excessive energy.

In addition, it is preferable that the milling time of a mill, such as an attention mill, is 3 to 10 hours in the process of forming a plate. At this time, if the milling time is less than 3 hours, it is difficult to manufacture a powder having an average particle diameter of 100 μm or less, and if it exceeds 10 hours, there may be a problem in that impurities are excessively mixed.

In addition, a solvent such as methanol, alcohol, and acetone may be used for a mill, such as an attention mill, in the process of forming a plate. And it is preferable that the weight ratio (solvent/powder) of the solvent and the powder (amorphous alloy ribbon) is 0.5 to 2.0. At this time, when the weight ratio of the solvent and the powder is less than 0.5, it is difficult to manufacture the amorphous alloy powder having a plate-like structure with a uniform surface, and when it exceeds 2.0, the manufacturing time of the amorphous alloy powder is excessively required.

In addition, it is preferable that the weight ratio (ball/powder) of the ball and powder used in the plate-like texture process based on the attention mill is 5-10. At this time, if the weight ratio is less than 5, milling time of 10 hours or more is required, and if the weight ratio exceeds 10, a problem of excessive wear due to direct collision with the balls may occur due to an excessive amount of input balls.

The second heat treatment step (S250) according to the present invention is a step of heat-treating the alloy powder having a plate structure in order to remove the stress inside the alloy powder due to the milling treatment and improve the soft magnetic properties of the alloy powder.

More specifically, the heat treatment step (S250) is a nanocrystalline alloy such as Fe-Si-B-Nb-Cu-based, Fe-Si-CP-Cu-based, among fine-grained amorphous alloy powders generated through the pulverizing step (S200). Heat treatment is performed in a reducing atmosphere for 30 to 100 minutes at a temperature 10 to 50°C higher than the silver crystallization initiation temperature, and an amorphous alloy such as Fe-Si-B or Co-Fe-B is 20 to 50°C above the crystallization initiation temperature. Heat treatment is performed in a reducing atmosphere for 30 to 100 minutes at a low temperature.

Subsequently, the slurry generation step (S300) is a step of generating a slurry solution using a mixture of a metal powder having a plate-like structure that has passed through the heat treatment step (S250) and a binder resin and a solvent. At this time, the solvent is added to the mixture to adjust the viscosity of the slurry together with the binder resin, and any one of water, alcohols, acetone, ether acetate, normal methylpyrrolidone, butyl cellosolve, and methylene chloride Alternatively, a mixture of these may be used.

In the slurry generation step (S300), a slurry solution having a viscosity of 5,000 to 10,000 cP is generated by adjusting the contents of the resin and solvent mixed in the mixture. At this time, if the viscosity is less than 5,000 cP, the magnetic sheet 10 is not formed because it is too thin, and if it exceeds 10,000 cP, a problem may occur in that the magnetic sheet 10 is cracked on the surface during the drying process.

This slurry solution is produced by adding 6 to 10 parts by weight of a binder resin and a solvent based on 100 parts by weight of the alloy powder having a plate structure. And the solvent is produced by mixing in a ratio of 4 to 10 times (weight ratio) than the binder resin. At this time, if the solvent is used less than 4 times, the movement of the alloy powder having a plate-like structure within the binder resin is restricted, and thus, the alloy powder having a plate-like structure in the magnetic sheet manufacturing step (S400) may not be arranged horizontally. have. In addition, when the solvent exceeds 10 times, there is a problem that the drying time increases when the magnetic sheet 10 is manufactured.

In addition, if the content of the binder resin is less than 6% by weight, the binding strength of the binder resin is weakened, and if the content of the binder resin exceeds 10% by weight, the shielding rate and the absorption rate of the magnetic sheet 10 decrease due to the excessive amount of the binder resin. Occurs.

Then, in the magnetic sheet manufacturing step (S400), a magnetic sheet 10 having a thickness of 0.1 mm to 0.3 mm is generated with the slurry solution generated through the slurry generating step (S300).

Specifically, in the magnetic sheet manufacturing step (S400), after processing the amorphous alloy powder having a plurality of plate-like structures horizontally inside the magnetic sheet 10, the slurry solution is dried and the solvent present in the magnetic sheet 10 Volatilize. Then, the dried slurry is pressurized with a pressing device such as a press machine to produce a magnetic sheet 10 having a thickness of 0.30 mm or less, preferably 0.1 mm to 0.30 mm.

As an embodiment, in the magnetic sheet manufacturing step (S400) according to the present invention, the slurry solution generated through the slurry generation step (S300) is applied on a release film, and then dried at a temperature in the range of 60 to 90°C, and then 120 to A magnetic sheet 10 having a density of 3.5 to 4.5 g/cm ² is produced by molding at a pressure of 50 to 150 kgf/cm ² on a hot press maintained at 175°C.

At this time, when the molding temperature is less than 120°C, the binder is not sufficiently softened, resulting in a problem that the thickness of the sheet is uneven, and when it exceeds 175°C, the binder resin is dissolved. In addition, if the molding pressure is less than 50 kgf/cm ^2, sufficient sheet molding density does not come out, and if it exceeds 150 kgf/cm ² , damage to the sheet due to overpressure may occur.

In addition, in the magnetic sheet manufacturing step (S400), the magnetic sheet 10 is cut to a specified standard through a tape casting method. Here, the tape casting method is a method of forming a sheet on a moving blade or a moving conveying film with a certain thickness according to the purpose.

Thereafter, the bonding means forming step (S500) is a step of providing a conductive bonding means 20 on one surface of the magnetic sheet 10 exposed to the outside, and applying a conductive bonding means 20 or attaching a conductive double-sided tape. .

Finally, the attaching step (S600) is a step of in close contact with the soft magnetic alloy thin ribbon 30 to the conductive bonding means 20 provided on the magnetic sheet 10 through the bonding means forming step (S500), the magnetic sheet ( Attach the soft magnetic alloy thin ribbon 30 to the surface of 10).

Hereinafter, it will be described in more detail through specific Examples 1 to 4 and experimental examples of the present invention.

[Example 1]

1. After heat-treating an amorphous alloy (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ) ribbon with a thickness of 10 μm and a width of 10 cm in a hydrogen gas atmosphere at 460° C., a temperature lower than 500° C., the crystallization initiation temperature, Grinding by hand to form 1 kg of amorphous alloy powder having an average particle diameter of 1 cm

2. After putting 1 kg of amorphous alloy powder and 10 kg of ball (SUJ420J2) with a diameter of 5 mm and 1 kg of alcohol into the container in the attraction mill, the rotation speed of the attraction mill was set to 500 rpm and operated for 5 hours. An amorphous alloy flake powder having a plate structure having an average thickness of 1.1 μm, an average particle diameter of 50 μm, and an aspect ratio of 45 was produced.

3. The amorphous alloy powder (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ) having the plate-like structure was subjected to heat treatment at 520°C, which is 20°C higher than the crystallization initiation temperature, for 30 minutes in a reducing atmosphere of hydrogen gas to make nanocrystallization. An alloy powder was prepared.

4. After mixing 500 g of nanocrystalline alloy powder (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ) having a heat-treated plate-like structure and SBR resin as a binder resin, 50 g, which is 10 parts by weight of nanocrystalline alloy powder, and 250 g of toluene as a solvent, Stirring to prepare a slurry solution.

5. The slurry solution was uniformly applied on a release film to prepare a sheet, and then dried sufficiently at a temperature of 90°C to volatilize the solvent component.

6. The sheet was hot-formed at 100kgf/cm ² for 1 minute through a hot press at 150° C. at which the binder softens to prepare a magnetic sheet.

7. A conductive adhesive [8330-19G, MG Chemical, Canada] was applied to the upper surface of the magnetic sheet to a thickness of 10 μm.

8. A composite magnetic shielding sheet having a thickness of 0.29 mm was prepared by attaching a soft magnetic amorphous alloy thin ribbon (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ) having a thickness of 35 μm on the conductive adhesive.

[Example 2]

Prepared in the same manner as in Example 1, but instead of a nanocrystalline alloy (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ) having an average thickness of 1.1 μm and an average particle diameter of 50 μm, an average thickness of 5 μm and an average particle diameter of 65 μm Nanocrystalline alloy (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ) flake powder was used, and SBR resin 37.5 g (7.5 parts by weight) and toluene 187.5 g were used instead of 50 g of SBR resin and 250 g of toluene. A composite magnetic shielding sheet was prepared.

[Example 3]

It was prepared in the same manner as in Example 1, but instead of a soft magnetic alloy foil having a thickness of 35 μm (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ), a soft magnetic alloy foil having a thickness of 35 μm (Fe ₇₈ Si ₁₃ B ₉ ) To prepare a composite magnetic shielding sheet.

[Example 4]

It was prepared in the same manner as in Example 1, but instead of a soft magnetic alloy foil having a thickness of 35 μm (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ), a soft magnetic alloy foil having a thickness of 150 μm (Fe-79Ni-2Mo permalloy ) To prepare a composite magnetic shielding sheet.

[Comparative Example 1]

A magnetic shielding sheet was prepared in the same manner as in Example 1, but with a single magnetic sheet without a conductive adhesive and a soft magnetic alloy foil.

[Comparative Example 2]

A composite magnetic material prepared in the same manner as in Example 1, but using a conductive metal foil having a thickness of 35 μm instead of a soft magnetic alloy foil having a thickness of 35 μm (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ) A shielding sheet was prepared.

Experimental example

The average particle diameter, microstructure, thickness of the shielding sheet, permeability, shielding rate, effective permeability, and thermal conductivity of the shielding sheets prepared according to Examples 1 to 4 and Comparative Examples 1 and 2 were evaluated. At this time, the average particle diameter of the amorphous and nanocrystalline alloy powder having a plate-like structure was measured with a particle size analyzer [Bettersize S2, K-One Nano, Korea], and the microstructure was photographed with HR-SEM [S-4800, Hitachi, Japan]. And the thickness of the shielding sheet was measured with a vernier caliper [500181-30, Mitutoyo, Japan], the shielding rate of the shielding sheet was measured with a network analyzer [ZVA40, Rohde & Schwarz, Germany], and the absorption rate was Precision Impedance Analyzer [4294A- CFG002, Agilent, USA]. In addition, the effective permeability of the shielding sheet was measured with an Impedance Analyzer [E4991A, Agilent, USA], and the thermal conductivity was measured with a thermal conductivity meter [LFA457, NETZCH, Germany], and the results are shown in [Table 1] and Figs. It is summarized in Figure 6.

3 and 4 are SEM photographs showing the microstructure of the amorphous alloy powder used in Example 1, and FIG. 5 is a graph showing the shielding rate for the shielding sheet manufactured through Examples and Comparative Examples, and FIG. 6 It is a graph showing the absorption rate for the shielding sheet manufactured through Examples and Comparative Examples.

Condition number	Sheet thickness(mm)	Effective permeability		Thermal conductivity (W/m·K)
		100 kHz	10 MHz
Example 1	0.29	250	110	31.5
Example 2	0.29	150	90	35.7
Example 3	0.29	160	90	38.3
Example 4	0.40	220	85	40.7
Comparative Example 1	0.25	150	110	5.3
Comparative Example 2	0.29	135	95	45.8

According to [Table 1] and FIGS. 5 and 6, the shielding rate of the composite magnetic shielding sheet of the present invention is 85 dB or more in the frequency band of 0.1 MHz to 10 GHz, and the absorption rate is 50% or more in the frequency band of 100 MHz to 10 GHz, It was confirmed that the thermal conductivity characteristic in the vertical direction was 30.0 W/m· or more, and the shielding rate, absorption rate, and thermal conductivity were significantly improved than when the magnetic sheet was used alone.

The reason for this is that the electromagnetic wave incident on the shielding sheet is partially absorbed by the soft magnetic alloy foil attached to one side, and when the rest is reflected again, it is considered to be absorbed and dissipated again in the magnetic sheet.

And according to [Table 1] and Figs. 5 and 6, the magnetic shielding sheet prepared in Comparative Example 2 has the same shielding rate as the magnetic shielding sheet of the present invention by attaching a metal foil made of Cu, but the effective permeability and absorption rate are lower. I could confirm that.

Next, a method of manufacturing a magnetic sheet will be described below.

7 is a flowchart illustrating a method of manufacturing a magnetic sheet according to the present invention.

Referring to FIG. 7, the method of manufacturing a magnetic sheet according to the present invention includes a heat treatment step (S1000) of heat-treating an amorphous alloy ribbon, a grinding step (S2000) of pulverizing the heat-treated amorphous alloy ribbon, and pulverized amorphous alloy powder. And a molding step (S3000) of mixing a binder resin to generate a magnetic sheet.

As shown in FIG. 7, the method of manufacturing a magnetic sheet according to the present invention includes a heat treatment step (S1000).

The heat treatment step (S1000) is a step of heat-treating the amorphous alloy ribbon at a temperature below the crystallization temperature, and pulverization and flakeization are easily progressed by partial rearrangement of surface cracks or over-solidified elements while maintaining the amorphous phase. . At this time, if the heat treatment for the amorphous alloy ribbon in the heat treatment step (S1000) is heat treated at a temperature exceeding the crystallization temperature of the amorphous alloy ribbon, the plate-like structure is not well formed in the process of grinding and flakeizing the amorphous alloy ribbon. There is a problem that the soft magnetic properties are greatly deteriorated due to non-uniform pulverization between crystal grains.

Specifically, in the heat treatment step (S1000), the amorphous alloy ribbon is preferably heat treated for 30 to 100 minutes at a temperature of a reducing atmosphere lower than the crystallization temperature of 20 to 150°C.

At this time, if the heat treatment temperature is conducted between a temperature 20°C lower than the heat treatment temperature of the crystallization temperature, there is a concern that some crystallization may occur. In addition, when the heat treatment temperature is lower than 150°C based on the crystallization temperature, the milling time may exceed 10 hours when manufacturing amorphous alloy flakes having an average particle diameter of 100 μm or less, which may increase impurities in the powder. .

In addition, if the heat treatment time is less than 30 minutes, sufficient heat treatment is not performed, and if the heat treatment time exceeds 100 minutes, the economy is poor.

It is preferable to use an amorphous soft magnetic alloy ribbon containing iron-based or cobalt-based as such amorphous alloy ribbon. Specifically, FeSiB-based, FeNbB-based, FeSiCP-based, etc. may be used as the iron-based, and CoFeB-based, etc. may be used as the cobalt-based.

As shown in FIG. 7, the method of manufacturing a magnetic sheet according to the present invention includes a grinding step (S2000).

The pulverizing step (S2000) is a step of pulverizing an amorphous alloy ribbon to generate amorphous alloy flakes having an average particle diameter of 100 μm or less, and may include a pulverizing process and a flake forming process.

It is preferable that the amorphous alloy flake powder produced through the pulverization step (S2000) has an average particle diameter of 20 μm to 100 μm, and an average aspect ratio (length/thickness) of 5 to 20.

At this time, if the average particle diameter is less than 20 μm, it takes excessive milling time, and if it exceeds 100 μm, there may be a problem that the surface roughness is poor during sheet manufacturing. And if the average aspect ratio is less than 5, the specific surface area of the amorphous alloy flake powder is small and the molding density is lowered. If it exceeds 20, the average particle diameter of the amorphous alloy flake powder exceeds 100㎛ and becomes coarse, resulting in a problem of poor surface roughness of the sheet. Can be.

In the crushing process constituting the crushing step (S2000) according to the present invention, the amorphous alloy ribbon heat-treated through the heat treatment step (S1000) is pulverized manually or by equipment such as a pulverizer.

In the flakeization process constituting the pulverization step (S2000) according to the present invention, the amorphous alloy ribbon pulverized through the pulverization process is finely pulverized using a mill such as a ball mill or an attrition mill, and plate-shaped. It produces flake powder of tissue.

More specifically, it is preferable that the milling speed of a mill, such as an attention mill, is 300 to 600 rpm in the flake process. At this time, when the milling speed is less than 300 rpm, sufficient pulverization does not occur, and when the milling speed exceeds 600 rpm, a problem of increased wear in the device and the ball may occur due to the application of excessive energy.

In addition, it is preferable that the milling time of the mill, such as the attention mill, is 3 to 10 hours in the flake process. At this time, if the milling time is less than 3 hours, it is difficult to manufacture a powder having an average particle diameter of 100 μm or less, and if it exceeds 10 hours, there may be a problem in that impurities are excessively mixed.

In addition, a solvent such as methanol, alcohol, and acetone may be used for a mill, such as an attention mill, in the flake process. And it is preferable that the weight ratio (solvent/powder) of the solvent and the powder (amorphous alloy ribbon) is 0.5 to 2.0. At this time, when the weight ratio of the solvent and the powder is less than 0.5, it is difficult to manufacture the flake powder having a flat surface structure, and when it exceeds 2.0, the manufacturing time of the flake powder is excessively required.

In addition, it is preferable that the weight ratio (ball/powder) of the ball and powder used in the flake process based on the attention mill is 5-10. At this time, if the weight ratio is less than 5, milling time of 10 hours or more is required, and if the weight ratio exceeds 10, a problem of excessive wear due to direct collision with the balls may occur due to an excessive amount of input balls.

8 is a flow chart illustrating a method of manufacturing a magnetic sheet according to another embodiment of the present invention.

Referring to FIG. 8, the method of manufacturing a magnetic sheet according to the present invention may further include a secondary heat treatment step (S2500) between the grinding step (S2000) and the forming step (S3000).

The secondary heat treatment step (S2500) is a step of performing a heat treatment to remove stress in the amorphous alloy flake powder generated through the pulverization step (S2000) and increase the orientation of atoms in a direction that facilitates magnetization.

More specifically, in the second heat treatment step (S2500), an amorphous alloy powder capable of sintering nanocrystallization, such as FeSiBNbCu-based, FeSiCPCu-based, and FeNbB-based, among the fine-grained flake powders generated through the pulverizing step (S2000) is 10 than the crystallization temperature Secondary heat treatment is carried out in a reducing atmosphere at a high temperature of ∼50℃ for 30 to 100 minutes, and amorphous alloys such as FeSiB-based or CoFeB-based, in which the internal structure is not nanocrystallized, have a temperature lower than the crystallization temperature of 20-50℃ for 30 to 100 minutes Secondary heat treatment is carried out in a reducing atmosphere. In this way, the temperature of the heat treatment is varied depending on whether or not the sintering of nanocrystallization is possible in order to improve the soft magnetic properties of the amorphous alloy flake powder.

For example, FeSiBNbCu-based Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ , Fe ₇₄ Si ₁₃ B ₉ Nb ₅ etc. may be used, and FeSiCPCu-based Fe ₇₈ Si ₃ C ₆ B ₅ P ₉ , Fe ₈₅ Si ₂ B ₅ P ₄ Cu ₁ or the like may be used, and Fe ₇₂ B ₁₄ Si ₁₀ Nb ₅ may be used as the FeNbB system. And FeSiB-based Fe ₇₈ Si ₁₃ B ₉ may be used, CoFeB-based Co ₇₀ Fe ₅ Si ₁₅ B _10, etc. may be used.

7 and 8, the method of manufacturing a magnetic sheet according to the present invention includes a molding step (S3000).

The forming step (S3000) is a step of generating a magnetic sheet from an amorphous alloy flake powder and a binder resin, and includes a slurry forming process (S3100) and a sheet forming process (S3200).

As the binder resin, a thermoplastic resin solution such as polyimide, PVA, urethane-based, and styrene-butadiene rubber (SBR) may be used for insulation and bonding between amorphous alloy flake powder. For example, as the binder resin, a binder resin in which 18% by weight of SBR solid powder and a small amount of a curing agent and a crosslinking agent are mixed may be used.

In this forming step (S3000), 100 parts by weight of the amorphous alloy flake powder and 6 to 10 parts by weight of the binder resin may be mixed. At this time, if the content of the binder resin is less than 6 parts by weight, the binding force of the binder resin is weakened, and if the content of the binder resin exceeds 10 parts by weight, the shielding rate and absorption rate of the magnetic sheet are deteriorated due to an excessive amount of the binder resin.

In the slurry formation process (S3100) constituting the molding step (S3000) according to the present invention, a slurry solution is produced by mixing amorphous alloy flake powder, a binder resin, and a solvent.

Specifically, the slurrying process (S3100) is a process of generating a slurry solution from a mixture of amorphous alloy flake powder, a binder resin, and a solvent. In this case, as the amorphous alloy flakes, a phosphate coating is treated to use an amorphous alloy flake provided with a phosphoric acid coating layer.

And in the slurrying process (S3100), a slurry solution having a viscosity of 5,000 to 10,000 cP is produced by adjusting the contents of the resin and solvent mixed in the mixture.

At this time, if the viscosity is less than 5,000 cP, the magnetic sheet is not formed because it is too thin, and if it exceeds 10,000 cP, the magnetic sheet may have a problem that cracks are formed on the surface during the drying process.

The solvent is added to the mixture to adjust the viscosity of the slurry together with the binder resin, and any one of water, alcohols, acetone, ether acetate, normal methylpyrrolidone, butyl cellosolve, methylene chloride, or these Mixtures of can be used.

This slurry solution is produced by adding 6 to 10 parts by weight of a binder resin and a solvent based on 100 parts by weight of the amorphous alloy flake powder. And the solvent is added in a ratio of 4 to 10 times (weight ratio) of the binder resin. At this time, if less than 4 times the solvent is used, the movement of the amorphous alloy flake powder within the binder resin is restricted, and thus a problem that the amorphous alloy flakes are not horizontally arranged in the sheet forming process (S3200) may occur. In addition, when the solvent exceeds 10 times, drying is difficult during manufacture of the magnetic sheet, resulting in an increase in drying time.

In the sheet forming process (S3200) constituting the forming step (S3000) according to the present invention, a magnetic sheet having a thickness of 0.3 mm or less is generated with the slurry solution generated through the slurry forming process (S3100).

In addition, in the sheet forming process (S3200), a plurality of amorphous alloy flakes are horizontally arranged inside the magnetic sheet, and then the slurry solution is dried so that the solvent present in the magnetic sheet is volatilized. Then, the dried slurry is pressed with a pressing device such as a press machine to produce a magnetic sheet having a thickness of 0.30 mm or less, preferably 0.1 mm to 0.3 mm. At this time, if the dried slurry is less than 0.1mm, the absorption and shielding rate decreases, and if it exceeds 0.3mm, it lacks economic feasibility when applied to electrical components.

As an embodiment, in the sheeting process (S3200) according to the present invention, the slurry solution generated through the slurrying process (S3100) is applied on a release film, and then dried at a temperature in the range of 60 to 90°C, and then 120 to 175 A magnetic sheet having a density of 3.5 to 4.5 g/cm ² is produced by molding at a pressure of 50 to 150 kgf/cm ² on a hot press maintained at °C.

At this time, when the molding temperature is less than 120°C, the binder is not sufficiently softened, resulting in a problem that the thickness of the sheet is uneven, and when it exceeds 175°C, the binder resin is dissolved. In addition, if the molding pressure is less than 50 kgf/cm ^2, sufficient sheet molding density does not come out, and if it exceeds 150 kgf/cm ² , damage to the sheet due to overpressure may occur. In addition, when the density is formed to be less than 3.5 g/cm ² , the effective permeability is lowered to 100 or less, and when the density is formed to exceed 4.5 g/cm ² , there is a problem that the applied molding pressure exceeds 150 kgf/cm ² .

As another embodiment, in the sheet forming process (S3200) according to the present invention, the slurry solution is applied in a sheet shape, and then dried at a temperature of 50°C to 150°C for 5 to 20 minutes to volatilize the solvent present in the slurry solution. After that, the magnetic sheet is produced by applying a pressure of 1 to 10 tons/cm 2 at a temperature of 200 to 500°C with a pressing device such as a press machine.

At this time, the pressurization of the pressurization device may be repeatedly performed several times, and preferably, it may be repeatedly performed 1 to 2 times.

Hereinafter, it will be described in more detail through specific Examples 5 to 9 and experimental examples of the present invention. However, Examples 5 to 9 and Experimental Examples are intended to aid understanding of specific examples of the above-described invention, and thus the scope of rights should not be construed as limiting.

[Example 5]

1. An amorphous alloy (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ) 1 kg with an average thickness of 20 μm and a width of 6 cm was placed at 460° C., which is 40° C. lower than the crystallization starting temperature of 500° C., under a hydrogen gas atmosphere. After the primary heat treatment for a minute, it was pulverized by hand to form 1 kg of amorphous alloy powder having an average particle diameter of 1 cm.

2. After putting 1 kg of the amorphous alloy powder and 10 kg of balls (SUJ420J2) with a diameter of 5 mm and 1 kg of alcohol into the container in the attention mill, the rotation speed of the attraction mill was set to 400 rpm and operated for 5 hours. To produce an amorphous alloy flake powder.

3. The amorphous alloy flake powder (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ) was subjected to a secondary heat treatment for 30 minutes under a reducing atmosphere of hydrogen gas at 520°C, a temperature 20°C higher than 500°C, a crystallization initiation temperature. I did.

4. After mixing 500 g of secondary heat-treated amorphous alloy flake powder (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ), 37.5 g (7.5 parts by weight) of SBR as a binder resin, and 187.5 g of toluene as a solvent, followed by stirring to make a slurry solution. To manufacture.

5. The slurry solution was uniformly applied on a release film to prepare a sheet, and then dried sufficiently at a temperature of 75° C. to volatilize the solvent component.

6. A magnetic sheet having a thickness of 0.25 mm was prepared by hot forming the sheet at a temperature of 150° C. for softening the binder at 100 kgf/cm ^{2 for} 1 minute through a hot press.

[Example 6]

It was prepared in the same manner as in Example 5, but the first heat treatment was performed at 350°C instead of the first heat treatment at 460°C to prepare a magnetic sheet.

[Example 7]

It was prepared in the same manner as in Example 5, but the rotation speed of the attention mill was set to 500 rpm instead of 400 rpm to prepare a magnetic sheet.

[Example 8]

In the same manner as in Example 5, a magnetic sheet was prepared using 30.0 g (6.0 parts by weight) of SBR resin and 150 g of toluene instead of 37.5 g of SBR and 187.5 g of toluene.

[Example 9]

A magnetic sheet was prepared in the same manner as in Example 5, but using SBR 50.0g (10.0 parts by weight) and toluene 250g instead of SBR 37.5g and toluene 187.5g.

[Comparative Example 3]

It was prepared in the same manner as in Example 5, but the first heat treatment at 520°C was performed instead of the first heat treatment at 460°C to manufacture a magnetic sheet.

[Comparative Example 4]

It was prepared in the same manner as in Example 5, but instead of 37.5 g of SBR and 187.5 g of toluene, a magnetic sheet was prepared using 25.0 g (5.0 parts by weight) of SBR and 125.0 g of toluene.

[Comparative Example 5]

It was prepared in the same manner as in Example 5, but instead of 37.5 g of SBR and 187.5 g of toluene, 60.0 g of SBR (12.0 parts by weight) and 300.0 g of toluene were used to prepare a magnetic sheet.

[Comparative Example 6]

But prepared in the same manner as in Example 5, instead of amorphous alloy flakes (Fe ₇₄ Si ₁₃ B ₉ Nb ₃ Cu ₁ ), sendust flakes having an average particle diameter of 60 μm and an average thickness of 1 μm [Fe-10Si -6Al alloy, Sanyo, Japan] was used to prepare a magnetic sheet.

Experimental Example 2

The average powder particle diameter, microstructure, thickness, density, permeability, shielding rate, and thermal conductivity of the magnetic sheet prepared according to Examples 5 to 9 and Comparative Examples 3 to 6 were evaluated. At this time, the powder average particle diameter of the amorphous alloy flake powder was measured with a particle size analyzer [Bettersize S2, K-One Nano, Korea], and the microstructure was photographed with HR-SEM [S-4800, Hitachi, Japan]. And the thickness of the magnetic sheet was measured with a vernier caliper [500-181-30, Mitutoyo, Japan], the density was measured with a density meter [AS220, Radwag, Poland], and the crystallization temperature was measured with a differential thermal analyzer [STA8000, Perkin Elmer, USA]. And the shielding rate of the magnetic sheet was measured with a network analyzer [ZVA40, Rohde & Schwarz, Germany], and the absorption rate was measured with a Precision Impedance Analyzer [4294A-CFG002, Agilent, USA].

And, the thermal conductivity was measured with a thermal conductivity meter [LFA457, NETZCH, Germany], and the results are summarized in [Table 2] and FIGS. 9 to 12 below.

9 is a graph showing the shielding rate for the magnetic sheet manufactured through the Example, FIG. 10 is a graph showing the shielding rate for the magnetic sheet manufactured through the Comparative Example, and FIG. 11 is a magnetic body manufactured through the Example It is a graph showing the absorption rate of the sheet, and FIG. 12 is a graph showing the absorption rate of the magnetic sheet manufactured through the comparative example.

Condition number	Heat treatment temperature (℃)	Milling speed (rpm)	Powder average particle diameter (㎛)	Average aspect ratio (length/height)	Binder content (parts by weight)	Molding density (g/cm3)	Thermal conductivity (W/m·K)
							Perpendicular	level
Example 5	460	400	65	15.8	7.5	4.2	1.5	5.3
Example 6	350	400	85	8.5	7.5	4.1	1.2	4.2
Example 7	460	500	55	9.0	7.5	3.8	1.3	4.5
Example 8	460	400	65	15.8	6.0	3.8	1.7	6.4
Example 9	460	400	65	15.8	10.0	4.2	1.1	5.5
Comparative Example 3	520	400	25	3.2	7.5	3.7	0.8	4.0
Comparative Example 4	460	400	65	15.8	5.0	4.0	1.3	6.1
Comparative Example 5	460	400	65	15.8	12.0	3.3	0.7	3.5
Comparative Example 6			45	40.9	10.0	3.7	0.5	3.0

According to [Table 2] and FIGS. 9 and 11, the magnetic sheet of the present invention has a shielding rate of 30 dB or more from 1 MHz to 10 GHz frequency band, an absorption rate of 5% or more, and a thermal conductivity characteristic of 1.0 W/ in the vertical direction. It was confirmed that it was m·K or more, and the thermal conductivity characteristic in the horizontal direction was 4.0W/m·K or more.

On the other hand, according to [Table 2] and FIGS. 10 and 12, it was confirmed that the shielding rate of the magnetic sheet, which was heat-treated above the crystallization initiation temperature, fell sharply to 20 dB or less among the magnetic sheet prepared as a comparative example. This is believed to be due to rapid crushing and low aspect ratio.

In addition, if the content of the binder resin is less than 6.0 parts by weight, the bonding strength with the binder resin is insufficient, resulting in lower molding density, resulting in a lower shielding rate. As it fell, it could be confirmed that the shielding rate, absorption rate, and heat dissipation characteristics fell.

Although described above with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the present invention described in the following claims. You will understand that you can.

[Explanation of code]

10: magnetic sheet

20: conductive adhesive means

30: soft magnetic alloy foil

Claims (16)

1. Magnetic sheet containing amorphous alloy powder of a plate-like structure subjected to nanocrystallization;

   Conductive bonding means provided on the surface of the magnetic sheet; And

   A composite electromagnetic wave shielding sheet comprising a soft magnetic alloy foil attached to the surface of the magnetic sheet through the adhesive.
2. The method of claim 1, wherein the magnetic sheet

   Composite electromagnetic wave shielding sheet, characterized in that the thickness is 0.1 to 0.3 mm.
3. The method of claim 1, wherein the magnetic sheet

   Composite electromagnetic wave shielding sheet comprising 6 to 10% by weight of a binder resin based on 100% by weight.
4. The method of claim 1, wherein the plate-shaped amorphous alloy powder is

   Composite electromagnetic shielding sheet, characterized in that the amorphous soft magnetic alloy powder containing iron or cobalt.
5. The method of claim 1, wherein the soft magnetic alloy foil

   Composite electromagnetic wave shielding sheet, characterized in that the amorphous or crystalline alloy foil containing iron or cobalt.
6. The method of claim 1, wherein the soft magnetic alloy foil

   Its thickness is 0.? Composite electromagnetic shielding sheet, characterized in that to 0.2 mm.
7. A heat treatment step of heat-treating the amorphous alloy ribbon at a temperature equal to or lower than the crystallization temperature;

   A grinding step of grinding the amorphous alloy ribbon to produce amorphous alloy flake powder having a length of 100 μm or less; And

   A method of manufacturing a magnetic sheet having excellent shielding and absorption of electromagnetic waves and heat dissipation properties, comprising a forming step of generating a magnetic sheet from the amorphous alloy flake powder and the binder resin.
8. The method of claim 7, wherein the amorphous alloy ribbon

   A method of manufacturing a magnetic sheet having excellent shielding and absorption of electromagnetic waves and excellent heat dissipation properties, characterized in that it is an amorphous soft magnetic alloy ribbon containing iron or cobalt.
9. The method of claim 7, wherein the heat treatment step

   A method of manufacturing a magnetic sheet having excellent electromagnetic wave shielding and absorption and heat dissipation properties, characterized in that the amorphous alloy ribbon is heat-treated at a temperature of a reducing atmosphere lower than the crystallization temperature of 20 to 150°C.
10. The method of claim 7, wherein the magnetic sheet

    A method of manufacturing a magnetic sheet having excellent shielding and absorption of electromagnetic waves and heat dissipation properties, characterized in that 6 to 10% by weight of a binder resin is mixed based on 100% by weight.
11. The method of claim 7, wherein the forming step

    Manufacturing of a magnetic sheet excellent in shielding and absorption of electromagnetic waves and heat dissipation characteristics characterized by producing a magnetic sheet having a density of 3.5 to 4.5 g/cm ² by molding at a temperature of 120 to 175°C at a pressure of 50 to 150 kgf/cm ² Way.
12. The method of claim 7, wherein the forming step

    A method of manufacturing a magnetic sheet having excellent shielding and absorption of electromagnetic waves and excellent heat dissipation characteristics, characterized in that the magnetic sheet is produced by applying a pressure of 1 to 10 tons/cm ² at a temperature of 200 to 500°C.
13. The method of claim 7, wherein the forming step

    A method of manufacturing a magnetic sheet having excellent shielding and absorption of electromagnetic waves and excellent heat dissipation properties, characterized in that a magnetic sheet having a thickness of 0.3 mm or less is produced.
14. The method of claim 7, wherein between the grinding step and the forming step

    A method of manufacturing a magnetic sheet having excellent electromagnetic wave shielding and absorption and heat dissipation characteristics, further comprising a second heat treatment step of heat-treating the amorphous alloy flake powder.
15. The method of claim 14, wherein the secondary heat treatment step

    When the amorphous alloy flake powder is FeSiBNbCu-based, FeSiCPCu-based, or FeNbB-based, it is heat-treated at a temperature of 10 to 50° C. higher than the crystallization temperature.
16. The method of claim 14, wherein the secondary heat treatment step

    When the amorphous alloy flake powder is FeSiB-based or CoFeB-based, heat treatment is performed at a temperature of 20 to 50° C. lower than the crystallization temperature.

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