KR20170040776A - Method for manufacturing magnetic shielding unit - Google Patents

Abstract

Provided is a method of manufacturing a magnetic sheet. According to an embodiment of the present invention, the method of manufacturing the magnetic sheet includes: (1) crushing a magnetic body to manufacture a magnetic layer formed of magnetic body fragments so as to improve the flexibility of the magnetic sheet; (2) adding a thin film coating layer forming composition onto the magnetic layer to form a thin film coating layer for maintaining the magnetic body fragments in a predetermined shape, buffering external force applied to the magnetic body fragments, and reducing an eddy current generated in the magnetic layer under a magnetic field; and (3) forming the thin film coating layer by solidifying the thin film coating layer forming composition. Accordingly, the magnetic sheet has a reduced manufacturing cost and is very easy to manufacture, and the manufactured magnetic sheet is remarkably excellent in flexibility with improved mechanical strength such as tensile properties and bending properties despite significant improvement in workability. Accordingly, even when the magnetic sheet is stored, transported, attached to an object to be attached and when an electronic apparatus provided therein with the object is used, the magnetic body provided in the magnetic sheet is prevented from being deteriorated in physical properties such as permeability due to physical damage such as unintentional cracking, the magnetic sheet is attached with excellent adhesion even when there is a step on an adherend surface of the object to be attached, the influence of a magnetic field on a component of a portable terminal device or a human body is blocked, the transmission/reception efficiency and a transmission/reception distance of data and/or a wireless power signal are significantly increased, and the above functions are sustained for a long time. Therefore, the present invention can be widely used for various portable devices such as mobile appliances, smart home appliances, or devices for the Internet of Things.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing a magnetic sheet,

The present invention relates to a magnetic sheet, and more particularly, to a magnetic sheet capable of preventing deterioration of durability due to deterioration of magnetic properties such as reduction of magnetic permeability and peeling of a magnetic sheet, a module including the same, and a portable device will be.

(NFC) function to portable electronic devices such as mobile phones, PDAs (personal digital assistants), iPads, notebook computers, tablet PCs, and the like. Recently, products incorporating wireless power transmission technology have been commercialized. A new type of wireless power transmission (WLC) technology is a technology that enables a portable electronic device to charge a battery by directly transmitting power to a portable electronic device by adopting an electromagnetic induction method or an electromagnetic resonance method without using a power line. There is an increasing trend of portable electronic devices adopting the technology.

The short-range communication or the wireless power transmission may be performed through transmission / reception of a signal in a specific operating frequency band. Since the signal uses a magnetic field induced by a current in a transmitting antenna, (Magnetic material) in order to prevent deterioration of the performance, efficiency, human body, peripheral electronic products, or other components in the apparatus.

On the other hand, in recent portable electronic devices, there is a tendency that the magnetic sheets provided in the portable electronic devices are also required to be realized with a thin thickness. However, a magnetic material such as a magnetic material such as ferrite, which is provided in a conventional magnetic sheet, is very brittle and difficult to be formed into a thin plate-like thickness without cracking or damage. Further, even if the magnetic body is formed into a thin plate-like thin plate to be provided in the magnetic sheet, the produced sheet is placed on a portable apparatus, specifically, a wireless power transmission antenna for receiving a power signal transmitted for performing wireless power transmission, There is a problem that cracks and physical damage are easily generated in the magnetic body in the magnetic sheet in the process of making the magnetic sheet.

In addition, when a magnetic sheet having a slim profile is adhered to a surface having a step difference, a conventional magnetic sheet is remarkably poor in flexibility, so that it is difficult to adhere to the step portion, and cracks or damage may occur in the magnetic material when an external force is applied.

Furthermore, even if a portable electronic device is manufactured without causing cracks or damage to the magnetic body, physical damage such as cracks may easily occur to the magnetic body due to impact such as dropping of the user's electronic device.

The physical damage such as cracks and micro fragmentation generated in the magnetic body provided on the magnetic sheet by the above-described cases remarkably lowers the magnetic property such as magnetic permeability of the magnetic body, and therefore, the initial physical property of the magnetic sheet designed first , There is a serious problem that performance deterioration or performance itself can not be expressed.

Therefore, it is possible to realize a thinner and thinner portable electronic device in response to the trend of small size and small size, and to prevent magnetic property deterioration due to physical damage of the magnetic body occurring in the process of storing, transporting and attaching the magnetic sheet to the adherend surface It is urgent to develop a magnetic sheet capable of continuously exhibiting desired physical properties.

KR 10-2012-0113624 A

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a magnetic sheet which is capable of reducing manufacturing cost, making a manufacturing process very easy, and improving mechanical strength such as tensile property, It is possible to prevent deterioration of physical properties such as permeability due to cracking of the magnetic material provided on the magnetic sheet even when the sheet is stored, transported, adhered to the adherend, and an electronic device provided with the adhered material is used, It can be adhered with excellent adhesion even when it is present. At the same time, the influence of the magnetic field on the parts such as the portable terminal and the human body using the same is blocked, and the data / wireless power transmission transmission / reception efficiency / transmission / reception distance is significantly increased, The present invention also provides a method of manufacturing a magnetic sheet.

According to an aspect of the present invention, there is provided a magnetic recording medium comprising: (1) a magnetic layer formed by shattering a magnetic material to improve the flexibility of the magnetic sheet; (2) A thin film coating composition is formed on the magnetic layer in order to maintain the magnetic particle fragments in a predetermined shape, to buffer an external force applied to the magnetic particle fragments, and to form a thin film coating layer for reducing eddy currents generated in the magnetic layer under a magnetic field Adding; And (3) solidifying the thin film coating layer forming composition to form a thin film coating layer.

In addition, in the step (1), 30% or more of the fragments having a diameter of 50 탆 or more may be included among the whole magnetic body fragments included in the magnetic layer.

Also, in the step (2), a thin film coating layer forming composition may be added so that the thin film coating layer forming composition can be filled in the spacing space between the magnetic body fragments.

The thin film coating layer forming composition may include a polymer compound including at least one of a natural polymer compound and a synthetic polymer compound and may further include a curing component for crosslinking the polymer compound, The composition may include a rubber compound as a synthetic polymer compound, and the rubber compound may include a polymer in which ethylene, propylene and a diene monomer are copolymerized.

The thin film coating layer forming composition may have a viscosity of 10 to 3000 cps.

In addition, the step (1) may include disposing a temporary protective member on one surface of the magnetic body to prevent scattering and loss of the magnetic body to be crushed, thereby breaking the magnetic body.

The present invention also provides a method of manufacturing a magnetic recording medium, comprising the steps of: (I) disrupting a magnetic substance to improve the flexibility of the magnetic sheet to produce a magnetic layer formed of magnetic substance fragments; (II) A thin film coating composition for forming a thin film coating layer for keeping the magnetic body fragments in a predetermined shape, buffering an external force applied to the magnetic body fragments, and reducing a eddy current generated in the magnetic layer under a magnetic field Adding; (III) partially or completely solidifying the thin film coating layer forming composition so that the magnetic layer formed of the magnetic body fragments can be maintained in a predetermined shape, thereby forming a thin film coating layer; (Iv) preparing a plurality of magnetic layers in which the thin film coating layer is formed, and stacking the magnetic layers so that a thin film coating layer is interposed between adjacent magnetic layers; And (V) completely solidifying or re-solidifying the thin film coating layer.

At this time, any one or more of the solidification and the solidification may be performed by sequentially or simultaneously applying at least one of heat, light, and pressure.

The magnetic material may be an amorphous alloy or a nano-crystal grain.

Hereinafter, terms used in the present invention will be described.

As used herein, the term "thin film coating layer" means that the composition for forming a thin film coating layer is solidified, and the term "solidifying" means that the liquid thin film coating layer forming composition has changed to a solid state to such a degree that a predetermined shape can be maintained. The solid phase includes a complete solid state, a state that is partially solid or a state capable of having fluidity when an external force is applied.

According to the present invention, the magnetic sheet production method significantly reduces the production cost, facilitates the production process, and improves the mechanical strength such as the tensile property and the bending property of the magnetic sheet to be produced, although the workability is remarkably improved The permeability due to physical damage such as unintentional cracking of the magnetic body provided on the magnetic sheet even during the use of the electronic device provided with the adhered adherend, Deterioration of physical properties can be prevented. In particular, the magnetic sheet according to an embodiment of the present invention can remarkably reduce magnetic loss and heat generation due to eddy currents generated in a magnetic sheet under a magnetic field. Further, even when there is a step on the surface to be adhered to the adherend, the adhesive can be adhered with excellent adhesion. At the same time, it is possible to prevent the influence of the magnetic field on the parts such as the mobile terminal or the human body using the mobile terminal, and to increase the transmission / reception efficiency / transmission / reception distance of the data and / And can be widely applied to various portable devices such as a smart appliance or an Internet of Things.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a magnetic sheet embodied in a manufacturing method according to an embodiment of the present invention,
FIG. 2 is a schematic view showing a manufacturing process using a crushing apparatus used for manufacturing according to an embodiment of the present invention, FIG. 2 (a) is a view showing a manufacturing process using a crushing apparatus for crushing a magnetic body through irregularities provided on a roller, 2b is a view showing a manufacturing process using a crushing device for crushing a magnetic body through a metal ball provided on a support plate,
3 is a schematic view showing the shape of debris observed on one surface of a magnetic layer formed of a magnetic debris after the step of crushing a magnetic material included in an embodiment of the present invention,
4A and 4B are diagrams showing the circumscribed circle diameter and the inscribed circle diameter of the fragment for evaluation of the degree of variability of the magnetic debris having the irregular shape,
FIG. 5 is a cross-sectional view of a magnetic sheet according to an embodiment of the present invention, in which a part of a thin film coating layer formed on one surface of a magnetic layer penetrates a part of a space between magnetic pieces,
6 is a cross-sectional view of a magnetic sheet embodied by a manufacturing method according to the present invention, showing a cross-sectional view of a magnetic sheet having a magnetic layer in three layers, and
7 is a photograph of the crushing apparatus according to FIG.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

The magnetic sheet according to the present invention comprises: (1) a step of crushing a magnetic body to improve the flexibility of the magnetic sheet to produce a magnetic layer formed of magnetic body fragments; (2) maintaining the magnetic body fragments in a predetermined shape; Adding a thin film coating layer forming composition to the magnetic layer to buffer an external force applied thereto and to reduce a eddy current generated in the magnetic layer under a magnetic field, and (3) solidifying the thin film coating layer forming composition to form a thin film coating layer To form a second layer.

First, in step (1) according to the present invention, a magnetic material is crushed to improve the flexibility of the magnetic sheet to produce a magnetic layer formed of the magnetic material fragments.

When the magnetic material is a magnetic material capable of exhibiting permeability properties of a desired magnetic sheet in a fragmented state, there is no limitation on the composition, crystal type, and microstructure of the sintered particles, and a magnetic material provided in a known magnetic sheet may be used . As an example of this, the magnetic body may be a soft magnetic body. Since the soft magnetic material has a very low coercive force with respect to the residual magnetic flux density and a high magnetic permeability, the shielding effect against electromagnetic fields is excellent. The soft magnetic material may include at least one of a metal soft magnetic material and a ferrite. The metal soft magnetic body may be at least one selected from the group consisting of Ni-Co alloy, Fe-Ni alloy, Fe-Cr alloy, Fe-Al alloy, Fe-Si alloy, Fe- And Cu-Nb-based alloys. The ferrite may be selected from the group consisting of Mn-Zn ferrites, Ni-Zn ferrites, Ni-Co ferrites, Mg-Zn ferrites, Cu-Zn ferrites, and cobalt substituted Y or Z hexagonal ferrites And may include at least one selected. The ferrite may be an oxide of at least three metals selected from the group consisting of iron oxide and nickel, zinc, copper, magnesium and cobalt such as Ni-Cu-Zn ferrite and Ni-Cu- May be used but not limited thereto. At this time, the content of nickel, zinc, copper, magnesium and cobalt in the ferrite can be changed according to the purpose, so that the present invention does not particularly limit it.

Meanwhile, in the magnetic sheet manufactured according to the embodiment of the present invention, the thinned coating layer solidified through the step (3) to be described later is completely filled (see FIG. 1) or partially filled The thin film coating layer filled in the space separated by the magnetic debris functions as an insulator for insulating the magnetic debris, thereby remarkably increasing the resistivity of the magnetic layer and minimizing the magnetic loss due to the eddy current generated in the magnetic layer under the magnetic field There is an advantage. Specifically, when the magnetic substance provided in the magnetic layer is a magnetic substance having a low electrical resistance (for example, a magnetic substance such as an Fe-Si-B based amorphous alloy), the magnetic field directed toward the magnetic sheet is affected by the eddy current The thin film coating layer penetrating into the space of the debris functions as an insulator to prevent the magnetic loss due to the eddy current and to minimize the heat generation and to improve the transmission and reception efficiency of the signal through the magnetic field with high sensitivity It can be sustained. Accordingly, the magnetic material included in the magnetic sheet manufactured according to the present invention may be preferably a magnetic material having a low specific resistance value, which may cause magnetic loss due to eddy current under a magnetic field.

Accordingly, a magnetic substance of a thin plate made of an amorphous alloy or a nanocrystalline alloy may be used as the magnetic substance.

First, the amorphous alloy may be an Fe-based or Co-based amorphous magnetic alloy, and it may be preferable to use an Fe-based amorphous magnetic alloy in consideration of a production cost. As the Fe-based amorphous magnetic alloy, for example, an Fe-Si-B alloy may be used. In this case, it is preferable that Fe is 70 to 90 atomic% and the sum of Si and B is 10 to 30 atomic%. The higher the content of Fe and other metals, the higher the saturation magnetic flux density. However, when the content of Fe element is excessive, it is difficult to form amorphous. Therefore, the content of Fe is preferably 70 to 90 at%. When the sum of Si and B is in the range of 10 to 30 at%, the amorphous forming ability of the alloy is the most excellent. In order to prevent corrosion in such a basic composition, corrosion resistance elements such as Cr and Co may be added in an amount of 20 at% or less, and a small amount of other metal elements may be added as necessary to impart different characteristics. For example, the Fe-Si-B alloy may have a crystallization temperature of 508 占 폚 and a Curie temperature (Tc) of 399 占 폚. However, such a crystallization temperature can be varied depending on the content of Si and B, or other metal elements added in addition to the ternary alloy component and its content. In addition, the magnetic material included in one embodiment of the present invention may be an Fe-Si-B-Cu-Nb amorphous magnetic alloy. Copper contained in the alloy improves the corrosion resistance of the alloy and prevents the size of the crystal from becoming large even if crystals are generated, and also improves magnetic properties such as magnetic permeability. It is preferable that the copper is contained in the alloy in an amount of 0.01 to 10 at%. If the copper content is less than 0.01 at%, the effect obtained by copper may be insignificant. If the copper content exceeds 10 at%, an amorphous alloy is produced There is a problem that can be difficult. In addition, niobium (Nb) contained in the alloy can improve magnetic properties such as magnetic permeability and is preferably contained in an amount of 0.01 to 10 at% in the alloy. If it is contained in an amount of less than 0.01 at%, niobium May be insignificant, and if it exceeds 10 at%, it may be difficult to produce an amorphous alloy.

There is no limitation on the shape before fracturing of the magnetic material, but the magnetic material may be in the form of a plate such as a ribbon sheet. Through this, the magnetic sheet having a uniform thickness can be easily manufactured and the particle size distribution of the magnetic substance pieces can be easily controlled It is possible to more easily satisfy the magnetic properties such as the magnetic permeability of the magnetic sheet set in seconds.

The thickness of the magnetic layer may be 1 to 300 mu m so as to facilitate the formation of the thinned magnetic sheet, but the present invention is not limited thereto.

On the other hand, the above-mentioned magnetic body may be manufactured by a known manufacturing method for each kind of magnetic body, or a commercially available magnetic body may be used.

At this time, as an example of directly manufacturing a magnetic body, a manufacturing method of a Ni-Zn-Cu-Co ferrite sheet having a magnetic body is as follows. First, nickel oxide, zinc oxide, copper oxide, cobalt oxide and iron trioxide are mixed in a predetermined composition ratio to obtain a raw material mixture. At this time, the mixture can be mixed by dry mixing or wet mixing, and the particle diameter of the raw material to be mixed is preferably 0.05 to 5 mu m. The components such as nickel oxide and zinc oxide contained in the raw material mixture may be in the form of a composite oxide containing the respective components of the nickel oxide and the zinc oxide or the components containing the components and may be cobalt ferrite, And may be included in the raw material.

Next, the raw material mixture is calcined to obtain a calcining material. The calcination is carried out in order to promote the thermal decomposition of the raw material, the homogenization of the components, the generation of ferrite, the disappearance of ultrafine powder by sintering, and the grain growth to an appropriate particle size so as to convert the raw material mixture into a form suitable for post processing. The calcination is preferably carried out at a temperature of 800 to 1100 DEG C for about 1 to 3 hours. The preliminary firing may be performed in an air atmosphere or an atmosphere having a higher oxygen partial pressure than the atmosphere.

Next, the calcination material obtained is pulverized to obtain a pulverized material. The pulverization is carried out in order to collapse the aggregation of the firing material to obtain a powder having an appropriate degree of sintering property. When the firing material forms a large lump, it may be pulverized by a wet milling method using a ball mill, an attritor or the like. The wet pulverization can be carried out until the average particle diameter of the pulverized material is preferably about 0.5 to 2 mu m.

Then, the obtained pulverizing material is slurried together with additives such as a solvent, a binder, a dispersing agent and a plasticizer to prepare a paste. Using this paste, a ferrite sheet having a thickness of 50 to 350 mu m can be formed. After the sheet is processed into a predetermined shape, a binder removal process and a firing process are performed to produce a ferrite sheet. The firing may be performed at a temperature of 900 to 1300 DEG C for about 2 to 5 hours. The atmosphere may be an atmospheric environment or an atmosphere having a higher oxygen partial pressure than the atmosphere. As another embodiment for producing the ferrite sheet, the ferrite powder and the binder resin may be mixed and then manufactured by a known method such as a powder compression molding method, an injection molding method, a calendar method, or an extrusion method.

The magnetic layer prepared by the above-described method can be manufactured by crushing the magnetic body prepared by the above-mentioned method. In the magnetic layer in the step (1), the magnetic debris collects at a constant height and occupies a certain area. And each of the fragments may be in an immobilized state. The reason for crushing the magnetic material is that it is difficult to break or break when the magnetic material is in the form of a fragment having a smaller area than that of a sheet having an area of a certain level or more and the magnetic layer in which the magnetic material fragments are gathered is smaller than the magnetic layer formed of the magnetic material before the fracture It is possible to have excellent flexibility. Specifically, in order to make the magnetic sheet slimmer and thinner, the thickness of the magnetic body provided on the magnetic sheet must be very thin at the same time. The magnetic bodies provided in the conventional magnetic sheet are very brittle, and when the thickness of the magnetic body is thin, There is a problem that the permeability after cracking is significantly lower than the permeability when the plate is formed before cracking occurs due to cracking or breaking into fine fragments.

In addition, the magnetic sheet having a very thin structure has a problem of significantly reducing workability when it is stored, transported, and put into a process as a part of a product after manufacturing. Specifically, the magnetic sheet is disposed on an adhered surface on which an antenna or the like is formed, and is generally adhered to an adhered surface on which an antenna is formed so as to improve antenna characteristics and prevent dislocation of the magnetic sheet. 1, the magnetic sheet 100 may be attached to an adhered surface (not shown) through the adhesive member 130, and the first adhesive layer 130b of the adhesive member 130 The removal of the release film 130a is carried out in advance. However, in order to peel off the release film 130a from the magnetic sheet 100, an external force equal to or higher than a certain level is required. However, when the thickness of the magnetic substance is extremely thin, the magnetic force easily and significantly cracks due to the external force. Accordingly, in order to prevent the deterioration of the physical properties due to the cracks, a great effort is made to peel off the release film so as not to cause a crack, and the workability is remarkably lowered. Further, even when a portable device is manufactured with a great effort to prevent cracks from occurring in the magnetic body, cracks and cracks are generated in the magnetic body due to impacts such as dropping during handling of the user, There is a problem that can not be done.

However, as the magnetic material is crushed through the step (1) and is included in the magnetic sheet in a fragmented state, even if the cross-sectional thickness of the magnetic sheet is reduced, it is possible to block the fear that cracks may further occur in the magnetic material due to external force. The magnetic sheet including the magnetic substance in the form of a fragment may be included in the magnetic sheet in a fragmented state by crushing the magnetic substance. In this case, the magnetic sheet including the magnetic substance in the initial state may be initialized to exhibit excellent characteristics in terms of transmission / reception efficiency and transmission / And the initial physical properties can be continuously maintained in the manufacturing step of the finished product in which the magnetic sheet is mounted and further in the use stage of the finished product so that the magnetic sheet having the non-fragmented magnetic body (for example, magnetic body) It is possible to eliminate a fear of a decrease in physical properties due to unintentional fragmentation occurring in the signal transmission / reception performance and a significant decrease in the signal transmission / reception performance due to this.

The method of crushing the magnetic body may be employed without limitation as long as it is a known crushing method of a magnetic body. For example, the magnetic material can be passed through a crushing device to slice the magnetic material into irregular pieces, and then the pressure is applied to planarize the magnetic layer so that the aggregate of magnetic material pieces has a desired thickness, Space can be reduced.

The method of applying pressure to the magnetic body may be performed by applying a pressure to the shredded pieces together with the shredding in the shredding apparatus, or may further perform a separate pressing process after shredding the magnetic body.

Specifically, as shown in FIG. 2A, a plurality of first rollers 11 and 12 having irregularities 11a and 12a and second rollers 21 and 22 corresponding to the first rollers 11 and 12, respectively, The magnetic material 51 is crushed and pressed to be planarized by passing the magnetic material 51 through a crusher having the third roller 13 and the fourth roller 23 corresponding to the third roller 13 The magnetic body 51 can be further pressed to be planarized. On the other hand, as shown in FIG. 2A, the magnetic body 51 may further include a temporary protective member 52 on one side thereof to pass through the crushing device. The temporary protective member 52 may prevent scattering and loss of the magnetic material to be crushed It is possible to make the environment of the workplace more comfortable and to prevent an increase in the material cost due to the lost magnetic body. The temporary protective member 52 may have a pressure-sensitive adhesive layer on one surface thereof, and may temporarily adhere to the magnetic body or adhere to the magnetic body, and may pass through the crushing device in a physically placed state. The temporary protective member 52 may be a conventional PET film or paper, and is not particularly limited in material.

2A, a support plate 30 having a plurality of metal balls 31 mounted on one surface thereof, and rollers 41 and 42 positioned above the support plate 30 for moving the to-be- The magnetic body 50 'can be crushed by putting the magnetic body 50' into the crushing apparatus and applying pressure through the metal ball 31. The shape of the ball 31 may be spherical, but is not limited thereto. The shape of the ball 31 may be a triangle, a polygon, an ellipse, or the like. The shape of the ball located on the support plate may be one shape or a mixture of various shapes .

According to an embodiment of the present invention, the shape of the shattered magnetic body may be irregular in the step (1). However, in order to further prevent the unintentional breakage, fragmentation, and breakage of the unintentional magnetic piece fragments which may occur as the magnetic sheet is warped or bent, it is preferable that at least one side of some of the pieces is crushed (See FIG. 3). When the magnetic sheet includes a debris having a curved shape at one side, there is an advantage that adjacent debris and collision or friction can be reduced, thereby preventing additional debris of the debris.

More preferably, the number of fragments having at least one curved shape is at least 10%, preferably at least 30%, more preferably at least 50%, and even more preferably at least 70% of the total number of fragments in the magnetic layer have. If the number of fragments having a curved shape of at least one side is less than 10% of the total number of fragments, the improvement in flexibility may be insignificant and the fragments to be finer than the fragments provided at the beginning due to external impact may increase, And the like.

In addition, the average particle size of the single fragment of the magnetic body fragments may be 50 to 5000 탆. If the average particle diameter exceeds 5,000 mu m, there is a problem that additional debris breakage or fragmentation is increased, and maintenance of the initial physical property design value of the magnetic sheet may be difficult. If the average particle size of the fragments is less than 50 탆, the magnetic properties such as magnetic permeability of the magnetic body before crushing must be remarkably high. However, there is a restriction on the selection of the magnetic body to select the magnetic body having high magnetic permeability. There is a problem that it is difficult to design the initial physical properties of the magnetic sheet. On the other hand, the mean particle size of the debris means the volume average diameter measured by a laser diffraction particle size distribution meter.

On the other hand, in order to further prevent breakage and fragmentation of the fragments, it is preferable that the fragments of the magnetic material have a degree of deformation of one side of the fragment according to the following formula 1 of not more than 8.0, preferably not more than 6.5, more preferably not more than 4.0 Preferably not less than 20%, more preferably not more than 3.5, even more preferably not more than 3.0, more preferably not more than 2.5, still more preferably not more than 2.0, still more preferably not more than 1.5 , Preferably 30% or more, more preferably 40% or more, still more preferably 50% or more, still more preferably 60% or more, still more preferably 70% or more.

[Equation 1]

In Equation (1), the diameter of the circumscribed circle of the fragment means the longest distance between any two points on one side of the fragment (R ₁ in FIG. 4A and R _{2 in} FIG. 4B) A circle passing through two points corresponds to a circumscribed circle of debris. The diameter of the inscribed circle of the fragment means the diameter of the inscribed circle having the largest diameter among the inscribed circles in contact with two or more sides present on one side of the fragment (r ₁ in FIG. 4A and r ₂ in FIG. 4B). The large degree of deformation of one side of the debris means that the shape of one side of the debris is long (refer to FIG. 4A) or includes a sharp portion (see FIG. 4B), which means that further debris may be broken or fragmented do.

Accordingly, it is preferable that the number of fragments having a large degree of differentiation among the magnetic fragments included in the magnetic layer 110a is less than a predetermined ratio. Accordingly, a fragment having a one-side variance of 8.0 or less of the fragment according to Equation (1) 10% or more, and more preferably 20% or more of the fragments satisfying the above conditions may be included. If the degree of debris exceeding 8.0 is less than 10%, the microfragmentation of the additional magnetic debris may cause a significant deterioration of physical properties such as permeability and the desired initial property design value may not be maintained.

The shape of the magnetic layer may be a polygonal shape such as a pentagon, a circular shape, an elliptical shape or a partially curved shape in addition to a rectangular shape and a square shape in correspondence with an application form of the antenna for short range communication, It may be a mixed shape of straight lines. In addition, it is preferable to have a sheet-like shape so as to realize a thinned magnetic sheet.

Next, as step (2) according to the present invention, a step of adding a thin film coating layer forming composition to the magnetic magnetic layer formed in step (1) is performed.

The thin film coating layer forming composition is formed by solidifying in the step (3) described below to prevent loss of aggregates of aggregates in a state of being separated and having a predetermined shape, and at the same time fixing and supporting each of the magnetic particle fragments, So as to buffer the external force applied to the magnetic body fragments and to prevent oxidation of the magnetic body due to penetration of moisture. In particular, since the thin film coating layer has a very low resistivity, it functions as an insulator for a magnetic substance having a large magnetic loss due to an eddy current under a magnetic field, thereby preventing magnetic loss due to eddy currents.

The composition for forming a thin film coating layer can easily adhere magnetic pieces after solidification and is excellent in shape retaining ability to have a predetermined shape (for example, a sheet shape) as a coating layer itself and is easily broken by an external force It is possible to realize a material exhibiting excellent physical properties such that it can be realized as a thin film without decreasing the flexibility of the magnetic layer and exhibiting physical properties that do not deteriorate workability due to lack of stickiness due to less tacky at room temperature after solidification Can be used as a thin film coating layer forming composition without limitation.

Preferably, the composition for forming a thin film coating layer may include a polymer compound of at least one of a natural polymer compound and a synthetic polymer compound, and further includes a curing component for crosslinking the polymer compound depending on the kind of the selected polymer compound .

The composition of the thin film coating layer-forming composition may be in the form of a liquid. For this purpose, the polymer compound may be in a liquid phase or may be dissolved or dispersed in a separate solvent to have a liquid phase, or a polymer compound may be melted to have a liquid phase property. It may vary depending on the type of polymer compound.

Among the above-mentioned polymer compounds, natural polymer compounds may be at least one of protein-based polymer compounds such as glue and gelatin, carbohydrate-based polymer compounds such as starch, cellulose and derivatives thereof and complex polysaccharides, and natural rubber compounds such as latex.

In addition, the synthetic polymer compound may include at least one of a thermoplastic polymer compound, a thermosetting polymer compound, and a rubber compound. The thermoplastic polymer may be selected from the group consisting of polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyacrylonitrile resin, acrylonitrile-butadiene-styrene (ABS), styrene- acrylonitrile , Methacrylic resin, polyamide, thermoplastic polyester (Ex. Polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and the like), polycarbonate, polyphenylene sulfide resin, polyamideimide, polyvinyl butyral (Polytetrafluoroethylene (PTFE) and polychlorotrifluoroethylene (PCTFE)), phenoxy resins (e.g., polytetrafluoroethylene), polyvinylformaldehyde, polyvinyl formal, polyhydroxypolyether, polyether, polypthalamide, , A polyurethane-based resin, a nitrile-butadiene resin, and the like. The thermosetting polymeric compound may include at least one of a phenol resin (PE), a urea resin (UF), a melamine resin (MF), an unsaturated polyester resin (UP), and an epoxy resin. The rubber compound may be at least one selected from the group consisting of styrene-butadiene rubber (SBR), polybutadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), polyisobutylene (PIB) rubber, acrylic rubber, Chloroprene, and the like.

The composition for forming a thin film coating layer included in one embodiment of the present invention prevents inadvertent micro fragmentation of a magnetic body by improving the buffering action of a thin coating layer formed by solidification and further improves the flexibility of the magnetic sheet, A synthetic polymer compound, more preferably a rubber compound, may be included in the polymer compound, and as an example thereof, a polymer in which ethylene, propylene and a diene monomer are copolymerized may be included in the rubber compound. At this time, the copolymerization molar ratio of the respective monomers may be changed according to the purpose, so that the present invention is not particularly limited thereto.

When the polymer compound selected as one component included in the composition for forming a thin film coating layer is crosslinked to form a thin film coating layer, the curable component that can be further included in the composition is a known curing compound capable of curing the selected specific polymer compound The ingredients can be used without limitation. As a non-limiting example, amine compounds, phenol resins, acid anhydrides, imidazole compounds, polyamine compounds, hydrazide compounds, dicyandiamide compounds, etc. may be used alone or in combination of two or more. Examples of the curing component of the aromatic amine compound include m-xylene diamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodearyl diphenylmethane, diaminodiphenyl ether, 1,3-bis (4-aminophenoxy) phenyl] sulfone, 4,4-bis (4-aminophenoxy) -Aminophenoxy) biphenyl, 1,4-bis (4-aminophenoxy) benzene, and the like, which may be used alone or in combination. Examples of the phenol resin curing component include phenol novolac resins, cresol novolac resins, bisphenol A novolac resins, phenol aralkyl resins, poly-p-vinylphenol t-butylphenol novolac resins, naphthol novolac resins, and the like , Which may be used alone or in combination.

When the composition for forming a thin film coating layer further includes a curable component, the content of the curable component may vary depending on the kind of the selected polymer compound and the curable component, so that the present invention is not particularly limited thereto. For example, And 5 to 60 parts by weight of the curable component. If the content of the curable component is less than 5 parts by weight, the curing reaction may be weak and the flexural and tensile properties may not be exhibited at the desired level. If the content exceeds 60 parts by weight, the reactivity with the polymer compound may be increased, And may deteriorate physical properties such as long-term storage property.

In addition, the composition for forming a thin film coating layer included in one embodiment of the present invention may further include a solvent, a curing accelerator, and other additives in addition to the polymer compound and the curable component.

These solvents can be used without limitation in the case of solvents commonly used in coating compositions, and as a non-limiting example, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), ketones such as cyclohexanone, Methylcellosolve, ethylene glycol dibutyl ether, and butyl cellosolve acetate. The amount of the solvent to be used is not particularly limited, but is preferably 10 to 500 parts by weight per 100 parts by weight of the polymer compound.

Since the curing accelerator can be determined depending on the specific kind of the polymer compound and the curable component, the present invention is not particularly limited thereto, and examples thereof include amine-based, imidazole-based, phosphorus-based, Boron-based curing accelerators, etc. These can be used alone or in combination. The content of the curing accelerator is preferably about 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight per 100 parts by weight of the polymer compound.

The other additives may specifically be selected from the group consisting of a pH adjusting agent, an ion scavenger, a viscosity adjusting agent, a thixotropic agent, an antioxidant, a heat stabilizer, a photostabilizer, an ultraviolet absorber, a colorant, a dehydrating agent, a flame retardant, Fungicide, preservative, and the like. The specific kind of each additive may be any known additives, and the present invention is not limited thereto.

When the composition for forming a thin film coating layer contains a curable component, the composition may be a one-component composition in which a polymer compound and a curable component are mixed, or either one component may be mixed with another component at a time for semi-curing and / Two-component type composition, which may vary depending on the kind of the specific polymer compound, the kind of the curing component and the specific curing method, and thus the present invention is not particularly limited thereto.

The viscosity of the composition for forming a thin film coating layer may be in the range of 10 to 3,000 cps. Thus, the coating layer can be uniformly coated on the magnetic body with a very thin thickness, thereby forming a thin coating layer after curing. However, the composition may be varied depending on the specific method of adding the thin film coating layer forming composition onto the magnetic material. For example, in the case of the silk screen method, the viscosity may be 1,000 to 30,000 cps.

A specific method of adding the above-mentioned thin film coating layer forming composition onto the magnetic layer can be used without limitation as long as a known coating composition is added to the coated surface, and as a non-limiting example, a blade coating, a flow the composition may be added to the magnetic layer by methods such as flow coating, casting, printing, transfer, brushing, dipping or spraying. In this case, the thickness of the thin film coating layer on which the coating film is to be formed and the spacing between the fragmented magnetic materials may be set differently depending on the degree of filling the composition, so that the present invention is not particularly limited thereto.

At this time, in order to remarkably prevent magnetic loss due to the increased eddy current and improve the buffering force by external force, the composition for forming a thin film coating layer added to the magnetic layer in an aggregate state composed of magnetic body fragments permeates into the spacing space between the magnetic body fragments (See FIG. 5) or all of the space (see FIG. 1), and furthermore, it is possible to coat even the magnetic debris existing on the surface opposite to the one surface of the magnetic layer to which the thin film coating layer forming composition is added. 1, the first thin film coating layer 110b1 is formed on one surface of the magnetic layer 110a and fills all of the spaced spaces between the magnetic fragment pieces 111. Further, the first thin film coating layer 110b1 is formed on one surface of the magnetic layer 110a, there is a second thin-film coating layer (110b ₂₎ is also formed on the other surface, wherein the second thin-film coating layer (110b ₂₎ is formed by solidification after a thin film coating composition for forming a part from the top of the magnetic layer (110a) flows seep downward Lt; / RTI > As shown in FIG. 1, when the magnetic debris 111 is completely coated with the thin film coating layer forming composition, the resistivity of the magnetic layer is remarkably improved, and the magnetic loss due to the eddy current can be further reduced.

On the other hand, the amount of the thin film coating layer-forming composition to be added on the magnetic layer may vary depending on the viscosity of the composition, the thickness of the desired thin film coating layer, and the like. Preferably, the thickness of the thin film coating layer formed after solidification is 10 μm or less , And more preferably 5 μm or less. This can contribute to the thinning of the entire magnetic sheet.

Next, in step (3) according to the present invention, the thin film coating layer forming composition is solidified to form a thin film coating layer.

The solidification of the thin film coating layer forming composition to be performed in the step (3) is a process of modifying the liquid thin film coating layer forming composition into a semi-solid or solid state by drying, cooling and / or chemical reaction, Can be added.

The thin film coating layer solidified through the drying process may be a polymer compound alone, a mixture of a polymer compound and a curing component, or a mixture of a polymer compound in a partially cured or fully cured state by a curing component Lt; / RTI >

In addition, the thin film coating layer solidified through cooling may be formed by cooling in a molten state a composition for forming a thin film coating layer containing a molten polymer compound, for example, a thermoplastic resin such as polyethylene, and the thin film coating layer may be a polymer compound itself .

The thin film coating layer solidified through the chemical reaction by the chemical reaction may be a polymer compound formed by heat, light, or hybrid curing in which the polymer compound is mixed. Thus, the thin film coating layer may be formed by crosslinking the polymer compound with or without a curing component Lt; / RTI >

The choice of the degree of solidification may vary depending on the specific implementation. For example, in manufacturing a magnetic sheet having a plurality of magnetic layers, a thin film coating layer is maintained in a semi-solid state in order to substitute the thin film coating layer as an adhesive layer without using a separate adhesive layer for each magnetic layer . That is, the fully solidified thin film coating layer may be very difficult to adhere the fully cured thin film coating layer to another magnetic layer without adhesives, because there is little room temperature tackiness and preferably no adhesiveness, preferably for workability. However, the semi-solidified thin film coating layer has an advantage that two independently prepared magnetic layers can be attached through complete solidification without a separate adhesive. In addition, if the magnetic sheet further comprises a protective member or an adhesive member, a separate adhesive or double-sided tape or the like is required for attaching such a member. The semi-consolidated thin-film coating layer may be formed by completely solidifying the member . However, even if the thin film coating layer is not completely solidified in step (3), the thin film coating layer included in the finally produced magnetic sheet may further include a plurality of processes for solidifying the thin film coating layer to a completely solidified state.

The method for solidifying the composition for forming a thin film coating layer may vary depending on the kind of the polymer compound contained in the composition, and thus the present invention is not particularly limited thereto. As a non-limiting example, curing, which is one method of solidification, can be used without limitation, either by curing by solvent vaporization or by curing by heat / light / moisture. Preferably, the curing may be effected by applying one or more of heat, light and pressure sequentially or simultaneously.

First, the thermosetting can be performed at a temperature of 50 to 200 DEG C for 1 second to 10 minutes, and a known method can be used for the specific curing method, so that the present invention is not particularly limited thereto. As a non-limiting example, a separate heat source can be passed through and cured, and at this time, a certain pressure can be further applied, and as an example in which heat and pressure can be applied at the same time, The thin film coating layer forming composition can be cured by passing a magnetic material having the thin film coating layer forming composition added thereto.

In addition, if the radiation is photocured, the radiation applied may preferably be performed under the action of high-energy radiation, i.e. UV radiation or sunlight, preferably light having a wavelength of from 200 nm to 750 nm. As a radiation source or a UV light source, for example, a medium pressure or high pressure mercury vapor, etc., the vapor vapor can be modified by the administration of another element such as gallium or iron. A laser, a pulsed lamp (termed a UV flash lamp), a halogen lamp or an excimer radiation means may also be used. The radiation means can be installed in a fixed position and the magnetic sheet to be irradiated can move past the radiation source by means of a mechanical device or the radiation means can be movable and the magnetic body to be irradiated does not change its position during curing. Typically sufficient radiation doses for curing by UV curing are in the range of 80 mJ / cm ² to 5000 mJ / cm ² with a radiation intensity of 80 mW / cm ² to 3000 mW / cm ² . The radiation may also optionally be carried out, for example, in the presence of an insoluble gas atmosphere or an oxygen-depleted atmosphere, with the exception of oxygen. Suitable insoluble gases are preferably nitrogen, carbon dioxide, inert gases or combustion gases. The irradiation may also be performed by coating a dry layer having a medium that transmits radiation. Examples of such are synthetic films, glass or liquids such as water.

1, the magnetic sheet manufactured by the above-described method has a protective member 140 disposed on the magnetic layer 110a and an adhesive member 130 disposed on the bottom of the magnetic layer 110a, .

First, the protective member 140 functions to protect the magnetic sheet from external physical and chemical influences. For example, in the process of attaching the magnetic sheet to the substrate having the antenna, The magnetic sheet can be adhered to the substrate, and the magnetic sheet can be protected against the applied heat / pressure.

The protective member 140 may be formed at any desired time, but may be formed before the step (1), between the step (2) and step (3), or after the step (3) It is not. In order to form the protective member 140 on the thin film coating layer, a separate adhesive may be required. However, a separate adhesive may reverse the thinning of the magnetic sheet and increase the manufacturing cost. In this case, when the protective member is formed on the thin film coating composition in the step (2) and the solidification process in the step (3) is performed, there is an advantage that the protective member can be formed on the thin film coating layer without a separate adhesive. Also, as described above, in the case of the semi-hardened thin-film coating layer, the protective member can be formed on the thin-film coating layer without a separate adhesive.

The protective member 140 may be a protective film provided on the magnetic sheet. The protective member 140 may have heat resistance enough to withstand the heat or external force applied in the process of crushing the magnetic material or attaching the magnetic sheet, A protective member made of a material having mechanical strength and chemical resistance sufficient to protect the magnetic layer 110a against chemical stimulation can be used without limitation. As a non-limiting example, polypropylene, polyimide, crosslinked polypropylene, nylon, polyurethane resin, acetate, polybenzimidazole, polyimideamide, polyetherimide, polyphenylene sulfide (PPS). (PET), polytrimethylene terephthalate (PTT) and polybutylene terephthalate (PBT), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) and polychlorotrifluoroethylene PCTFE), and polyethylene tetrafluoroethylene (ETFE) may be used singly or in combination.

The protective member 140 may have a thickness of 1 to 100 μm, preferably 10 to 30 μm, but is not limited thereto.

Next, the adhesive member 130 serves to attach the magnetic sheet 100 to an antenna or a substrate provided with an antenna. The adhesive member 130 may include an adhesive layer 130b for attaching the magnetic sheet 100 to the attached surface and may further include a release film 130a for protecting the adhesive layer 130b. The release film 130a can be used without limitation in the case of a conventionally known release film which can be easily removed from the adhesive layer 130b. In the present invention, the release film 130a is not particularly limited thereto. It may be removed from the magnetic sheet 100.

The adhesive layer (130b) may be formed is a composition for forming an adhesive layer on the lower surface of the lower surface or the thin-film coating layer (110b ₂₎ of the magnetic layer (110a) is applied, the adhesive composition is applied on a release film (130a) formed in the adhesive layer (130b) Or the like. Further, the adhesive layer 130b may be a double-sided adhesive layer in which the adhesive layer-forming composition is coated on both sides of the support film to reinforce the mechanical strength.

6, a plurality of magnetic layers 210a ₁ , 210a ₂ , and 210a ₃ are formed on a magnetic sheet 200, and a plurality of magnetic layers 210a ₁ , 210a ₂ , and 210a _{3 are} formed on adjacent magnetic layers _{210a 1 / 210a 2, 210a 2} / 210a 3) and between the first magnetic layer (210a ₁₎ of the top / third magnetic layer (210a ₃₎ the lower layer coating layer on the _{(210b 1, 210b 2, 210b} 3, 210b 4) the (I) disrupting the magnetic substance to improve the flexibility of the magnetic sheet to produce a magnetic layer formed of the magnetic substance fragments, (B) preparing a magnetic layer formed of the magnetic substance fragments, (II) A thin-film coating layer-forming composition is applied on the magnetic layer in order to maintain the magnetic-piece fragments in a predetermined shape, to buffer an external force applied to the magnetic-piece fragments, and to form a thin-film coating layer for reducing eddy- (III) forming a thin film coating layer by partial solidification or complete solidification of the thin film coating layer forming composition so that the magnetic layer formed of the magnetic debris can be maintained in a predetermined shape, (IV) forming a thin film coating layer on the magnetic layer (V) stacking the magnetic layers so that a thin film coating layer is interposed between adjacent magnetic layers, and (V) completely solidifying or re-solidifying the thin film coating layer.

The above steps (I) to (V) are partially duplicated in the description of steps (1) to (3) of the above embodiment of the present invention.

First, in the step (III), the thin coating layer is partly solidified or completely solidified, so that the partial solidification is at least such that the shape retention force that is broken or unstoppable when the magnetic layer is lifted through the hand or other mechanism is expressed Can be solidified. The determination of the partial solidification or the complete solidification may be determined depending on the specific kind of the polymer compound contained in the thin film coating layer. For example, in the case of including a polymer compound which can be hardened and solidified, It may be difficult to adhere to the thin film coating layer formed on the substrate. Further, in the case of the thin film coating layer formed by cooling molten polyethylene, if the additional heat is further added even after the solidified state, the thin film coating layer completely melted can be melted again and the magnetic layer can be thermally fused, It may be in a state.

Next, in the step (IV), a plurality of magnetic layers including a thin film coating layer formed on one surface are stacked so that a thin film coating layer is positioned between adjacent magnetic layers so that the magnetic layers can be bonded to each other.

Then, in the step (V), the partially solidified thin film coating layer is completely solidified so that the magnetic layers can be adhered to each other, and when the completely solidified thin film coating layer is re-melted and re-solidified, a plurality of magnetic layers are laminated Sheet can be implemented.

As shown in Fig. 6, a magnetic sheet having a plurality of magnetic layers may have a limitation in exhibiting properties suitable for some applications depending on the case, such as the magnetic sheet according to Fig. 1, in which a magnetic layer having only a single magnetic layer is provided. That is, in order to improve the magnetic properties of the magnetic sheet, a magnetic material having excellent magnetic characteristics such as magnetic permeability may be selected, or the magnetic layer may be increased in thickness when the magnetic permeability is somewhat low. However, in order to increase the thickness of the magnetic layer, the thickness of the magnetic layer of the single layer forming the magnetic layer must be increased to a certain level or more. However, it is difficult to produce a magnetic sheet, for example, a ribbon sheet in a thick state, and since the surface and inside of the sheet are not uniformly and uniformly fired in the firing step, the fired particle structure may be different, have. Accordingly, a plurality of magnetic layers themselves can be provided to increase the magnetic saturation capacity of the magnetic layer by increasing the overall thickness of the magnetic layer in the magnetic sheet. The magnetic sheet having the laminated magnetic layer can further improve the antenna characteristics of the intended use, The transmission / reception efficiency and the transmission / reception distance can be remarkably improved.

When a plurality of magnetic layers are provided in the magnetic sheet, it is preferable to provide 2 to 12, more preferably 3 to 10, magnetic layers. If the number of stacked layers of the magnetic layer exceeds 12, the degree of improvement of the desired antenna characteristics may be insignificant. If the number of stacked layers is less than 2, the improvement range of the desired antenna characteristics is insignificant It may not be possible to improve antenna characteristics to the desired level. In the plurality of magnetic layers, the physical properties, microstructure, composition and the like of the magnetic material contained in each magnetic layer may be the same, some of the same or different.

6, the protective member 240 may be attached to the first thin film coating layer 210b ₁ without a separate adhesive or may be attached to the first thin film layer 210b ₁ through an adhesive layer (not shown) coating layer (210b ₁₎ and to the phase or omit the first thin-film coating layer (210b ₁₎ may be attached to the first magnetic layer (210a _1), or the first magnetic layer (210a ₁₎ and the first thin-film coating layer (210b ₁₎ (V) after the process is temporarily disposed while performing the above-described processes without any adhesion on the substrate. The formation time of the protective member 240 is not particularly limited in the present invention.

In addition, as shown in FIG. 7, an adhesive member 230 for adhering to the surface to be attached with the magnetic sheet may be provided under the fourth thin-film coating layer 210b ₄ . At this time, the adhesive member 230 may be attached to the lower portion of the fourth thin-film coating layer 210b ₄ through a separate adhesive layer (not shown). 7, the fourth thin film coating layer 210b ₄ is formed on the lower surface of the third magnetic layer 210a ₃ , for example, when the thin film coating layer is not provided on the lower surface of the magnetic layer positioned at the lowermost part The bonding member 230 may be directly bonded to the lower portion of the third magnetic layer 210a ₃ through an adhesive layer (not shown). The forming time of the adhesive member 230 is not particularly limited in the present invention.

In addition, the magnetic sheets 100, 100 ', and 200 of the various embodiments implemented by the manufacturing method according to the present invention may include at least one functional layer (not shown) for shielding and / One or more of them may be provided. The magnetic sheet having the functional layer prevents an increase in frequency fluctuation of the antenna combined with electromagnetic waves due to electromagnetic waves such as power supply noise, thereby reducing the defective ratio of the antenna. In addition, It is possible to prevent the durability of the parts due to the deterioration of the parts, the deterioration of the functions, and the discomfort due to the heat transfer to the user.

In addition, when the functional layer provided on the top and / or bottom of the magnetic sheet is a functional layer having a heat radiation function, the thermal conductivity in the horizontal direction of the magnetic sheet can be improved. In addition, since the magnetic layer included in the magnetic sheet contains air in the spaced minute space between the magnetic debris, thermal conduction in the vertical direction of the magnetic layer can be suppressed due to the adiabatic effect due to the air in the micro space.

Specifically, an electromagnetic wave shielding layer, a heat dissipation layer, and / or a composite layer in which the electromagnetic interference shielding layer, the heat dissipation layer, and / or the composite layer are stacked on the protective member 140 of the magnetic sheet 100 and / A functional layer such as a composite layer may be provided. For example, a metal foil such as copper, aluminum, or the like, which is excellent in thermal conductivity and conductivity, may be attached to the upper portion of the protection member 140 through an adhesive or a double-sided tape. Or a combination of these metals is formed on the protective member 140 by a known method such as sputtering, vacuum deposition, chemical vapor deposition, or the like To form a metal thin film. When the functional layer is provided through an adhesive, the adhesive may be a known adhesive. For example, an acrylic, urethane, or epoxy adhesive may be used. On the other hand, heat dissipation performance can be imparted to the adhesive. For this purpose, a known filler such as nickel, silver or carbon material can be mixed with the adhesive, and the content of the filler may be the content of the filler in the known heat- It is not particularly limited in the present invention.

The thickness of the functional layer may be in the range of 5 to 100 탆, and more preferably in the range of 10 to 20 탆 in order to reduce the thickness of the magnetic sheet.

As described above, the magnetic sheets 100, 100 ', and 200 according to one embodiment of the present invention are complex with other magnetic sheets having different magnetic characteristics at a predetermined frequency to use different frequency bands And the characteristics of the antenna can be enhanced at the same time. In this case, the arrangement of the different magnetic sheets may be a laminated structure, and a certain one of the magnetic sheets may be disposed inside the other magnetic sheet The specific arrangement relationship is not limited in the present invention.

The magnetic sheet manufactured according to the embodiment of the present invention described above can be used for the purpose of magnetic shielding at a specific frequency and can be used for electromagnetic wave absorption in other specific frequency bands even though the same magnetic sheet is used. Further, it can be used as a magnetic body for an antenna core, not for electromagnetic wave shielding or absorption.

Hereinafter, exemplary embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are intended to aid understanding of the present invention, and the present invention is not limited by the following experimental examples.

Example  1. Magnetic sheet manufacturing

Rapid Solidification by Melt Spinning (RSP) Fe _{91 . 6} Si ₂ B ₆ Co _{0 . 2} Ni _{0 .2} amorphous alloy ribbon was cut into a sheet shape and then a 24 탆 thick ribbon sheet was subjected to heat treatment at 460 캜 for 1 hour in an air atmosphere to prepare a ribbon sheet. Thereafter, the shredding apparatus as shown in Figs. 2B and 7 was passed three times to produce a ribbon sheet formed of magnetic debris.

7 parts by weight of ethylene-propylene-diene rubber (EPDM) and 93 parts by weight of toluene were mixed to prepare a composition for forming a thin film coating layer. The ribbon sheet was coated with a barcoater (RDS 22) And dried at 100 DEG C for 1 minute to form a thin film coating layer having a thickness of 3 mu m. Since, 130 ℃ the ribbon and the sheets ^2, 10kg / cm 2 And laminated under roll press process conditions to produce a magnetic sheet.

Example  2 to 8.

The magnetic sheet was prepared in the same manner as in Example 1 except that the thin film coating layer forming composition was changed as shown in Table 1 below.

Comparative Example  One.

(Support base PET, KYWON CORPORATION, VT-8210C) having a thickness of 10 mu m was laminated on the above-described two ribbons To thereby produce a magnetic sheet interposed between and interposed between the sheets.

division bookbinder menstruum Kinds weight% Kinds weight% Example 1 EPDM 9 toluene 91 Example 2 CPE
(Chlorinated Polyethylene) 10 toluene 90 Example 3 Acrylic rubber 18 toluene 82 Example 4 polyethylene 14 MEK
(MethylEthylketone) 86 Example 5 EVA
(ethylene-vinyl acetate copolymer) 14 water 86 Example 6 Epoxy
(Bisphenol-A) 30 MEK 70 Example 7 Epoxy
(CTBN rubber modification) 18 Toluene / MEK 82 Example 8 PU
(polyurethane) 17 Toluene / MEK 83 Comparative Example 1 PET (polyethylene terephthalate) double sided tape

Experimental Example 1

The laminate prepared in the production steps of the magnetic sheets according to Examples and Comparative Examples was evaluated for adhesion. Specifically, in order to evaluate the adhesion of the thin film coating layer between the two laminated ribbon sheets, the magnetic sheet composed of the two ribbon sheets including the magnetic debris was separated by hand, and the degree of breaking of the magnetic sheet was evaluated, A very good case is indicated by?, A good case is indicated by O, a bad case is indicated by?, And a very bad case is marked by X. The results are shown in Table 2 below.

Experimental Example 2

The following properties of the magnetic sheet prepared through Examples and Comparative Examples were evaluated and shown in Table 2.

1. Evaluation of elongation

In order to measure the magnetic elongation force provided inside the magnetic sheet, the magnetic sheet was sampled with a sample of 3 cm x 3 cm in size, and 20 kg / cm ² The tensile strength of the magnetic sheet was maintained for 10 seconds and the degree of breakage of the magnetic sheet was evaluated and expressed as a value of 1 to 100 on the basis of the magnetic sheet prepared in Example 1. [ (The larger the number, the better the drawing power)

2. Assessment of the degree of prevention of peeling off of magnetic materials

In order to measure the degree of prevention of peeling of the magnetic debris contained in the magnetic sheet, the magnetic sheet was sampled with a sample of 3 cm x 3 cm in size, and 20 kg / cm ² And the result is visually evaluated. The result is evaluated as "good" when the magnetic material wave-front peeling is not observed at all, "good" when the magnetic material is O, A case of bad, and a case of very bad are indicated by X.

3. Evaluation of room temperature tack

The magnetic sheet was sampled with a size of 3 cm x 3 cm and tack was measured using a Probe Tack measuring instrument. The diameter of the probe was 5 mm and the measurement condition was load 200 gf After holding for 10 seconds with a force, the tack was measured by pulling at 10 mm / sec.

At this time, if the tack result of the upper / lower surface of the magnetic sheet is 10 gf or more, it is determined that the tack is excessive and indicated by O. When the tack is 10 gf or less, there is no problem.

division Adhesion Drawing force Degree of peeling of magnetic fragment Tack Example 1 O 100 ◎ X Example 2 O 85 X Example 3 O 94 ◎ X Example 4 ◎ 76 ◎ X Example 5 O 78 O Example 6 ◎ 74 ◎ O Example 7 ◎ 86 ◎ O Example 8 O 79 O O Comparative Example 1 62 (No magnetic substance) O

Referring to Table 1 and Table 2,

In the case of the magnetic sheets of Examples 1 to 8 including the magnetic layer and the thin coating layer formed of the shattered magnetic body fragments according to one example of the present invention, the adhesive strength, elongation force and selectivity It can be understood that the physical properties of the polymer are generally excellent.

Specifically, in the case of the magnetic sheet comprising the thin film coating layer containing 9 wt% of ethylene-propylene-diene rubber (EPDM) as in Example 1, the adhesive strength was the same as that of the other Examples, , The degree of peeling of the magnetic body fragments, and the tackiness.

Further, in the case of CPE which is a rubber material different from that of Example 1, and Examples 2 and 3 in which a thin film coating layer was formed with acrylic rubber, the properties of the whole of the magnetic piece were slightly different from those of Example 1 in terms of the degree of delamination.

Furthermore, Examples 4 to 8, in which a thin film coating layer was formed of a material other than a rubber material, showed somewhat lower physical properties than those of Examples 1 to 3 using a rubber material. However, Comparative Example 1 And it shows excellent characteristics in all aspects relative to contrast.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that the present invention, Various modifications and variations are possible.

100, 100 ', 200: magnetic sheet
110a, 110a ', 210a:
110b, 110b ', 210b: thin film coating layer
130, and 230:
140, 240: protective member

Claims (12)

(1) disrupting a magnetic material to improve the flexibility of the magnetic sheet to produce a magnetic layer formed of magnetic material fragments;
(2) A thin film coating composition is formed on the magnetic layer in order to maintain the magnetic particle fragments in a predetermined shape, to buffer an external force applied to the magnetic particle fragments, and to form a thin film coating layer for reducing eddy currents generated in the magnetic layer under a magnetic field Adding; And
(3) solidifying the thin film coating layer forming composition to form a thin film coating layer. The method according to claim 1,
Wherein at least 30% by number of the fragments having a diameter of 50 占 퐉 or more among all the magnetic debris fragments included in the magnetic layer are included in the step (1). The method according to claim 1,
Wherein the thin film coating layer forming composition is added so that the thin film coating layer forming composition can be filled in the spacing space between the magnetic body fragments. The method according to claim 1,
Wherein the composition for forming a thin film coating layer comprises a polymer compound comprising at least one of a natural polymer compound and a synthetic polymer compound. The method according to claim 1,
Wherein the thin film coating layer forming composition further comprises a curable component for crosslinking the polymer compound. The method according to claim 1,
Wherein the composition for forming a thin film coating layer has a viscosity of 10 to 3000 cps. 5. The method of claim 4,
Wherein the thin film coating layer forming composition comprises a rubber compound as a synthetic polymer compound. The method according to claim 6,
Wherein the rubber compound comprises a polymer in which ethylene, propylene and a diene monomer are copolymerized. The method according to claim 1,
In the step (1), a temporary protective member for preventing scattering and loss of the magnetic material to be crushed is provided on one surface of the magnetic material, thereby breaking the magnetic material. (I) disrupting a magnetic body to improve the flexibility of the magnetic sheet to produce a magnetic layer formed of magnetic body fragments;
(II) A thin film coating composition for forming a thin film coating layer for keeping the magnetic body fragments in a predetermined shape, buffering an external force applied to the magnetic body fragments, and reducing a eddy current generated in the magnetic layer under a magnetic field Adding;
(III) partially or completely solidifying the thin film coating layer forming composition so that the magnetic layer formed of the magnetic body fragments can be maintained in a predetermined shape, thereby forming a thin film coating layer;
(Iv) preparing a plurality of magnetic layers in which the thin film coating layer is formed, and stacking the magnetic layers so that a thin film coating layer is interposed between adjacent magnetic layers; And
(V) completely solidifying or re-solidifying the thin film coating layer. 11. The method of claim 10,
Wherein at least one of the solidification and solidification is performed by sequentially or simultaneously applying at least one of heat, light, and pressure. 11. The method according to claim 1 or 10,
Wherein the magnetic body is an amorphous alloy or a nanocrystal.

Images