KR101698043B1 - Manufacturing method of electromagnetic wave absorber with a shape and electromagnetic wave absorber designed by the method - Google Patents

Abstract

A method of manufacturing an electromagnetic wave absorber having a shape is provided. A method of manufacturing an electromagnetic wave absorber having a shape according to an exemplary embodiment of the present invention comprises: (a) a soft magnetic metal powder of 57 to 94 wt.%, An organic binder of 5 to 40 wt.% Of a silicon binder, (B) forming an electromagnetic wave absorbing sheet by forming two rolls of the slurry of the electromagnetic wave absorbing composition; (c) forming an electromagnetic wave absorbing composition slurry in a predetermined (D) applying a high temperature and a high pressure to measure the electromagnetic wave absorbing sheet so as to conform to the shape of the structure to be attached, thereby manufacturing an electromagnetic wave absorbing body, wherein the electromagnetic wave absorbing body is press- The manufacturing step includes compressing using a shape-shaping apparatus including a mold adapted to the shape of the structure to be attached.

Description

Technical Field [0001] The present invention relates to a method of manufacturing an electromagnetic wave absorber having a shape and an electromagnetic wave absorber,

The present invention relates to a method of manufacturing an electromagnetic wave absorber having a shape and an electromagnetic wave absorber produced thereby.

In recent years, the use of digital electronic devices has been increasing due to the development of the industry, and digital electronic devices are becoming faster, higher frequency, and more advanced in circuit signal processing speed of electronic devices, and the demand for miniaturization, It is accelerating.

As circuits have become more multilayered and densified to meet these demands, serious electromagnetic problems have emerged as new concerns. Particularly, with the increase in portable electronic devices due to downsizing, light weight, and thinness, the amount of exposure of electromagnetic waves to the human body has increased.

Research on the harmful effects of electromagnetic waves on the human body has been published. Therefore, in the advanced countries, studies are being actively conducted to regulate the adverse effects on electromagnetic waves.

In the conventional electromagnetic wave absorbing sheet, a soft magnetic metal powder or the like is mixed with an organic binder to prepare a slurry, which is then molded into a sheet by itself, or a slurry is coated on a polymer film such as a PET film, And then used as an electromagnetic wave absorber.

On the other hand, in the conventional method of manufacturing an electromagnetic wave absorber and the electromagnetic wave absorber, the shape of a rectangular parallelepiped is implemented by a primary curing and a secondary punching method, and the shape is implemented by 2 to 10 fold processing Respectively.

In addition, the conventional electromagnetic wave absorber manufacturing method and the electromagnetic wave absorber have another disadvantage in that the shape of the electromagnetic wave absorber is inferior in productivity due to nozzle clogging or wear due to metallic powder, loss of unnecessary material from the nozzle to the product And a large amount of bubbles.

An embodiment of the present invention is to provide a method of manufacturing an electromagnetic wave absorber having various shapes and capable of reducing electromagnetic noise, and to provide an electromagnetic wave absorber manufactured thereby.

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According to one aspect of the present invention, there is provided a method of manufacturing a magnetic recording medium, comprising the steps of: (a) mixing a soft magnetic metal powder of 57 to 94% by weight, an organic binder of 5 to 40% by weight of a silicon binder, and an additive of 1 to 10% Preparing an absorbent composite slurry; (b) forming an electromagnetic wave absorbing sheet by forming two rolls of the slurry of the electromagnetic wave absorbing composition; (c) determining the amount of the electromagnetic wave absorbing sheet to be formed in the shape of the article so that the electromagnetic wave absorbing sheet can be formed in the shape of the article having a thicker form than the electromagnetic wave absorbing sheet, Measuring by thickness and weight; (d) providing a shape mold including an upper mold and a lower mold corresponding to a shape of a structure to which the electromagnetic wave absorbing sheet is attached; And (e) disposing an electromagnetic wave absorbing sheet metered by the thickness and the weight of the finished article in a shape-and-mold apparatus having the shape mold, and then heating the electromagnetic wave absorbing sheet at a high temperature and a high pressure, ; A method for manufacturing an electromagnetic wave absorber is provided.
The step (a) may include the steps of (a-1) measuring the soft magnetic metal powder, the organic binder and the additive and stirring the mixture with a first kneader, and (a-2) And stirring the soft magnetic metal powder with a second kneader.

At this time, a high temperature of 100 to 300 ° C may be applied to the absorbent sheet for 30 to 500 seconds using the mold apparatus having the shape of the step (d).

At this time, in the step of compressing using the shape-mold apparatus, the pressure can be compressed to 200 kgf to 3000 kgf.

According to another aspect of the present invention, there is provided an electromagnetic wave absorber having a shape produced by the manufacturing method described above.

The electromagnetic wave absorber having a shape according to an embodiment of the present invention is not a sheet type but an electromagnetic wave absorber capable of realizing various shapes according to the shape of a structure to be attached through a shape mold press device having a shape other than a conventional injection process .

The method for manufacturing an electromagnetic wave absorber according to an embodiment of the present invention includes a first raw material stirring step and a second stirring step to prevent the soft magnetic metal powder from being broken and to allow dispersion to be performed well.

The method of manufacturing an electromagnetic wave absorber according to an embodiment of the present invention can reduce nozzle clogging, unnecessary loss, and the like in an injection molding process. Also, the shape press process can increase the production rate and production rate than injection molding.

The electromagnetic wave absorber manufactured by the method of manufacturing an electromagnetic wave absorber according to an embodiment of the present invention may have a shape suitable for the structure to which the electronic wave absorber is attached and may have a high electromagnetic wave absorption rate in a frequency band (10 MHz to 18 GHz) of the electronic device.

1 is a flowchart of a method of manufacturing an electromagnetic wave absorber having a shape according to an embodiment of the present invention.
2 is a process diagram showing a first raw material stirring step in a method of manufacturing an electromagnetic wave absorber having a shape according to an embodiment of the present invention.
3 is a process diagram showing a second raw material stirring step in a method of manufacturing an electromagnetic wave absorber having a shape according to an embodiment of the present invention.
FIG. 4 is a process diagram showing a step of forming an electromagnetic wave absorbing sheet by through-forming the slurry of the electromagnetic wave absorbing composition in the method of manufacturing an electromagnetic wave absorbing material having a shape according to an embodiment of the present invention.
5 is a process diagram showing a press molding step of an electromagnetic wave absorbing sheet metered by applying a high temperature and a high pressure in a method of manufacturing an electromagnetic wave absorbing member having a shape according to an embodiment of the present invention.
6 is a perspective view illustrating an electromagnetic wave absorber manufactured by a method of manufacturing an electromagnetic wave absorber having a shape according to an embodiment of the present invention.

Hereinafter, 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 or similar components are denoted by the same reference numerals throughout the specification.

1 is a flowchart of a method of manufacturing an electromagnetic wave absorber having a shape according to an embodiment of the present invention.

Referring to FIG. 1, a method for manufacturing an electromagnetic wave absorber having a shape according to an embodiment of the present invention includes steps (S10) of producing an electromagnetic wave absorbing composition slurry by stirring a soft magnetic metal powder, an organic binder and an additive, Forming a slurry by two rolls to form an electromagnetic wave absorbing sheet (S20). (S30) of measuring the electromagnetic wave absorbing sheet at a predetermined weight and a step (S40) of press-molding the electromagnetic wave absorbing sheet measured by applying a high temperature and a high pressure.

In an embodiment of the present invention, step (S10) of producing a slurry of an electromagnetic wave absorbing composition by stirring soft magnetic metal powder, an organic binder and an additive includes a first raw material metering and stirring step (S11) and a second raw material metering and stirring Step S12 may be included.

The method of manufacturing an electromagnetic wave absorber according to an embodiment of the present invention includes a first raw material metering and stirring step S11 and a second raw material metering and stirring step S12 to prevent breakage of the soft magnetic metal powder So that the dispersion can be performed well.

2 is a process diagram showing a first raw material stirring step in a method of manufacturing an electromagnetic wave absorber having a shape according to an embodiment of the present invention.

1 and 2, in one embodiment of the present invention, the first raw material is metered and mixed in a first kneader (Kneader) 10 in a first raw material metering and stirring step (S10). At this time, the first raw material may be the soft magnetic material powder 11, the organic binder 13, and the additive 15.

2, in one embodiment of the present invention, the soft magnetic material powder 11 is a metal powder mainly used for manufacturing an absorber having a high electromagnetic wave absorption efficiency.

At this time, the soft magnetic material powder 11 may be Permalloy, Sendust, Pure iron, Carbonyl iron, silicon steel, ferrite, or the like.

In addition, the magnetic properties of the absorber can be controlled by adjusting the particle size and the composition ratio of the soft magnetic metal powders 11.

Referring to FIG. 2, the organic binder 13 is a silicon binder having a chain-like molecular structure in which silicon having an organic group bonded thereto is linked by a siloxane bond (Si-O-Si).

At this time, the silicon binder 13 serves to control the viscosity of the electromagnetic wave absorber blend.

In an embodiment of the present invention, the silicone binder 13 has a low change in viscosity due to temperature, so that it can prevent the absorption layer from desorbing according to the temperature change when applied to an electric circuit. In addition, it is excellent in electrical insulation and suitable for an insulating portion of an electric circuit.

In addition, the organic binder 13 may be formed of an acrylic resin, a urea resin, a melamine resin, a fluorine resin, ethylene propylene diene monomer (EDPM), polypropylene, polyethylene, polyvinyl chloride, chlorinated polyethylene, PVDF polyvinylidenefluoride, polyesters, polyamides, polymethylmethacrylates, and the like.

In one embodiment of the present invention, the type of the organic binder 13 is not limited, and two or more kinds of polymer resins may be mixed and used in consideration of applicability, mechanical properties, and environmental friendliness. If the amount of the organic binder 13 is insufficient, it may be 5 to 40% by weight since it is difficult to mix with the soft magnetic material powder 11.

On the other hand, the additive 15 may be used in an amount of 1 to 10% by weight, depending on the binder, using a curing agent. At this time, the curing agent is added to the thermosetting resin to cause bridge bonding and cure.

In this case, the thermosetting resin may be a phenol resin, an epoxy resin or the like, and the phenol resin may be hexamethylenetetramine or the like, and the epoxy resin may be an amine, a polyamide, or the like.

Meanwhile, in an embodiment of the present invention, an industrial stirrer kneader is primarily used in the first raw material stirring step, and the soft magnetic metal powder and the silicon binder can form a uniform bonding state.

In an embodiment of the present invention, the second raw material weighing and stirring step (S12) is performed by adding the second raw material to the first raw material and mixing using a second kneader (20) of a stirrer.

3 is a process diagram showing a second raw material stirring step in a method of manufacturing an electromagnetic wave absorber having a shape according to an embodiment of the present invention.

3, the second raw material is added to a combination (hereinafter referred to as " compound ") 17 of the soft magnetic material powder 11, the organic binder 13 and the additive 15, Powder 21 may be additionally added to produce an electromagnetic wave absorbing composition slurry or a raw material in the form of an amorphous pellet (hereinafter referred to as " electromagnetic wave absorbing composition slurry ").

Further, the soft magnetic metal powder 21 can be used for manufacturing an absorber having a good electromagnetic wave absorption efficiency.

At this time, the soft magnetic metal powder 21 may be Permalloy, Sendust, Pure iron, Carbonyl iron, silicon steel, ferrite, or the like.

In addition, the magnetic properties of the absorber can be controlled by controlling the particle size and the composition ratio of the soft magnetic metal powders 21.

Meanwhile, in one embodiment of the present invention, the soft magnetic metal powder 21 can be processed into a plate-like (flake) shape. The radio wave absorption performance of the electromagnetic wave absorber according to the embodiment of the present invention may depend on the magnetic permeability of the soft magnetic metal powder 21. [

At this time, the magnetic permeability is represented by the multiple magnetic permeability (u) using the real magnetic permeability (u ') and the imaginary magnetic permeability (u'). However, when magnetic loss such as the electromagnetic wave absorber according to the embodiment of the present invention is used, (u ') may be more important.

In the electromagnetic wave absorber according to the embodiment of the present invention, it is important that the real magnetic permeability (u ') is distributed over the frequency band of the propagation noise to be absorbed.

Therefore, in an embodiment of the present invention, the plate-shaped soft magnetic metal powder 21 may have a high real relative permeability (u ') value. Thus, the soft magnetic metal powder 21 can be processed into a plate by using an induction milling machine or the like.

3, in the second raw material weighing and stirring step S12, the first raw material and the blend 17 in the stirring step S11 and the second raw material raw material The magnetic metal powder 21 is agitated using a second agitator kneader 20.

At this time, the second raw material and the stirring step (S12) allow the soft magnetic metal powder (21) and the first agitation additive (17) to form a uniform bonding state.

When the soft magnetic metal powder 21 is mixed with the soft magnetic metal powder 21 in the second raw material stirring step S12 at a content of less than 57% by weight, the electromagnetic wave absorber has almost no characteristics. Therefore, To 94% by weight.

At this time, if the content of the soft magnetic metal powder 21 is 57 to 94% by weight, the maximum electromagnetic wave absorption effect and heat dissipation property can be realized.

The method of manufacturing an electromagnetic wave absorber according to an embodiment of the present invention includes a first raw material and a stirring step (S11), a second raw material and a stirring step (S12), that is, dividing the stirring process into first and second , It is possible to prevent cracking of two or three kinds of the soft magnetic metal powders (11, 21), and to make it possible to achieve good dispersion.

On the other hand, in the step S20 of forming the electromagnetic wave absorbing sheet by through-roll molding the slurry of the electromagnetic wave absorbing composition in the embodiment of the present invention, the electromagnetic wave absorbing composition slurry 23 stirred in the second raw material weighing and stirring step (S12) Absorbing sheet (31).

FIG. 4 is a process diagram showing a step of forming an electromagnetic wave absorbing sheet by through-forming the slurry of the electromagnetic wave absorbing composition in the method of manufacturing an electromagnetic wave absorbing material having a shape according to an embodiment of the present invention.

 4, in the step S20 of forming the electromagnetic wave absorbing sheet by the roll-forming process of the slurry of the electromagnetic wave absorbing composition according to an embodiment of the present invention, the applied electromagnetic wave absorbing composition slurry 23 is formed Thereby removing the air bubbles and forming the electromagnetic wave absorbing sheet 31.

At this time, the turrol 30 is provided with two rotatable rolls, and the turrol molding is performed by putting the electromagnetic wave absorbing composition slurry 23 between two rotating rolls.

In one embodiment of the present invention, the thickness of the electromagnetic wave absorber slurry 23 to be supplied to the turbulator 30 is not limited, but may be 0.1 to 5.0 mm. At this time, when the thickness is 0.1 to 5 mm, the control of the troll 30 operation is easy, and the bubbles present in the electromagnetic wave absorber composition slurry 23 can be easily removed.

In one embodiment of the present invention, the electromagnetic wave absorbing composition slurry 23 may be pressed between two rolls of the trolley 30 to form the electromagnetic wave absorbing sheet 31 from which air bubbles in the electromagnetic wave absorbing composition slurry have been removed.

Meanwhile, in the step S30 of measuring the electromagnetic wave absorbing sheet at a predetermined size and weight in the embodiment of the present invention, the electromagnetic wave absorbing sheet 31 is distributed to a predetermined size in order to reduce loss of unnecessary materials.

At this time, in the step of measuring the electromagnetic wave absorbing sheet at a predetermined size and weight (S30), the electromagnetic wave absorbing sheet 31 is weighed to the thickness and weight of the finished product thicker than the electromagnetic wave absorbing sheet, do. At this time, the thickness of the electromagnetic wave absorbing sheet 31 subjected to the two-roll forming can be formed to be 5 mm or less. Since the electromagnetic wave absorber according to the embodiment of the present invention has a thickness of 50 mm or less, the electromagnetic wave absorber sheet is distributed so as to correspond to the thickness and weight of the finished article to be manufactured.

Meanwhile, in one embodiment of the present invention, the press forming step S40 for applying high temperature and high pressure to the metered electromagnetic wave absorbing sheet 33 may include a step S41 of compressing using the mold apparatus having the shape.

Further, in the press molding step (S40) of applying high temperature and high pressure to the metered electromagnetic wave absorbing sheet 33, the metered electromagnetic wave absorbing sheet 33 is formed through the hot press step.

For this purpose, referring to FIG. 5, the design of the shape metal mold 40 suitable for the product can be preceded. At this time, the shape die 40 is constituted by two upper and lower molds 41 and 43, and the shape thereof can be manufactured in accordance with the product. Here, the term " product " means a structure for attaching an electromagnetic wave absorber to shield electromagnetic waves, and it is possible to design the metal mold 40 having a shape corresponding to the shape of the structure to be attached.

At this time, in the step S41 of compressing using the mold apparatus having the shape, the pressure of 200 kgf to 3000 kgf can be applied, and the hot press process can be performed using the mold 40 having the shape.

5 is a process diagram showing a step of press molding with high temperature and high pressure applied to the electromagnetic wave absorbing sheet 33 measured in the method of manufacturing an electromagnetic wave absorber having a shape according to an embodiment of the present invention.

5, a method for manufacturing an electromagnetic wave absorber according to an embodiment of the present invention includes the steps of putting an electromagnetic wave absorbing sheet 33, which has been measured using a metal mold 40, into a shape metal mold 40, The electromagnetic wave absorber 50 having a shape can be produced by applying a high temperature of 100 to 300 DEG C for 30 to 500 seconds to the absorbent sheet for sufficient curing of the product.

6 is a perspective view showing an electromagnetic wave absorber having a shape manufactured by a method of manufacturing an electromagnetic wave absorber having a shape according to an embodiment of the present invention.

Referring to FIG. 6, the electromagnetic wave absorber 50 having a shape manufactured by the method of manufacturing an electromagnetic wave absorber according to an embodiment of the present invention may have a thickness (t) of 0.1 to 50 mm.

Accordingly, the electromagnetic wave absorber 50 having a shape manufactured by the method of manufacturing an electromagnetic wave absorber according to an embodiment of the present invention can have a shape adapted to the structure to which the electromagnetic wave absorber 50 is attached, The absorption rate may be high.

In addition, the electromagnetic wave absorber 50 having the shape shown in FIG. 6 is only an embodiment of the present invention, and the shape can be manufactured according to the product and can be formed in various shapes according to the shape of the product.

At this time, the electromagnetic wave absorber 50 having a shape manufactured by the method of manufacturing an electromagnetic wave absorber according to an embodiment of the present invention may have a shape that has flexibility and conforms to the size of the product.

Meanwhile, the method of manufacturing an electromagnetic wave absorber according to an embodiment of the present invention can reduce nozzle clogging, unnecessary loss, and the like in the injection molding process.

The method for manufacturing an electromagnetic wave absorber according to an embodiment of the present invention does not require hardening or solidification of a raw material by using a mold 40 having a shape to perform a hot pressing process, Time can be shortened.

In addition, the method of manufacturing an electromagnetic wave absorber according to an embodiment of the present invention can greatly improve the productivity compared to injection molding, and can be mass-produced in a short time.

Meanwhile, in the inspection and shipping step (S50) in the embodiment of the present invention, it is checked whether the electromagnetic wave absorber 50 having the shape processed by the shape press is manufactured without defect.

At this time, the thickness, appearance, and characteristics of the electromagnetic wave absorber 50 having the shape produced by the electromagnetic wave absorber manufacturing method according to an embodiment of the present invention may vary depending on the structure to which the electromagnetic wave absorber having the shape is attached.

The electromagnetic wave absorber having a shape according to an embodiment of the present invention can produce an electromagnetic wave absorber capable of realizing various shapes according to the shape of a structure attached through a mold apparatus having a shape other than a conventional injection process.

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 understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10: first kneader 11: soft magnetic material powder
13: Organic binder 15: Additive
17: Compound 20: Second kneader
21: soft magnetic metal powder 23: electromagnetic wave absorbing composition slurry
30: Tour roll 31: Electromagnetic wave absorbing sheet
33: Measured electromagnetic wave absorbing sheet 40: Shape mold apparatus
41: upper mold 43: lower mold
50: electromagnetic wave absorber having a shape

Claims (5)

(a) 57 to 94% by weight of a soft magnetic metal powder, 5 to 40% by weight of an organic binder which is a silicon binder, and 1 to 10% by weight of an additive according to the organic binder to prepare an electromagnetic wave absorbing composition slurry;
(b) forming an electromagnetic wave absorbing sheet by forming two rolls of the slurry of the electromagnetic wave absorbing composition;
(c) determining the amount of the electromagnetic wave absorbing sheet to be formed in the shape of the article so that the electromagnetic wave absorbing sheet can be formed in the shape of the article having a thicker form than the electromagnetic wave absorbing sheet, Measuring by thickness and weight;
(d) providing a shape mold including an upper mold and a lower mold corresponding to a shape of a structure to which the electromagnetic wave absorbing sheet is attached; And
(e) arranging an electromagnetic wave absorbing sheet metered by the thickness and the weight of the finished product in a shape-and-mold apparatus provided with the shape mold, and then heating the electromagnetic wave absorbing sheet at a high temperature and a high pressure so that the electromagnetic wave absorbing sheet is thicker than the electromagnetic wave absorbing sheet Compression; Wherein the electromagnetic wave absorber is formed of a metal. The method according to claim 1,
The step (a)
(a-1) measuring the soft magnetic metal powder, the organic binder and the additive, and stirring the resultant mixture with the first kneader;
(a-2) a second step of stirring the soft-magnetic metal powder and the combination of the step (a-1). The method according to claim 1,
Wherein a high temperature of 100 to 300 占 폚 is applied to the absorbent sheet for 30 to 500 seconds using a mold apparatus having the shape of step (d). The method according to claim 1,
And compressing the molded product at a pressure of 200 kgf to 3000 kgf in the step of compressing using the shape mold apparatus. An electromagnetic wave absorber having a shape produced by the manufacturing method according to any one of claims 1 to 4.

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