KR102076837B1 - Manufacturing method of eco-friendly electromagnetic intereference shielding materials including AgSnO2-carbon material - Google Patents

Abstract

The present invention relates to manufacturing of an ecofriendly electromagnetic wave shielding material with an addition of an AgSnO_2-carbon material based on agar and, more specifically, which uses the agar composed mostly of water as an electromagnetic wave shielding material, cost reduction is possible and is harmless to the human body, which is eco-friendly and has an excellent electromagnetic wave shielding effect.

Description

Manufacturing method of eco-friendly electromagnetic intereference shielding materials including AgSnO2-carbon material}

The present invention relates to an environmentally friendly electromagnetic shielding material using natural materials, and more particularly, using agar and / or konjac, which is a natural material, as an environmentally friendly electromagnetic shielding material, and adding a carbon material decorated with AgSnO ₂ to a high electromagnetic shielding performance. The present invention provides a method for producing an electromagnetic wave shielding composition and a composition for achieving the improvement.

Recently, with the development of electronic and communication devices, the convenience of human life is greatly improved, and at the same time, the problem of harmfulness caused by the exposure of electromagnetic waves generated from electronic devices is increasing. In particular, as the light weight, miniaturization and design of electronic devices are diversified, housing materials are replaced by metals and plastics, so that electromagnetic waves generated from the inside of the electromagnetic are easily leaked to the outside of the electromagnetic. These leaked electromagnetic waves can interfere with other surrounding electromagnetic waves, causing the electromagnetic waves to malfunction or even adversely affect the human body. Long-term exposure to strong electromagnetic waves, disturbance of the hormone secretion system or weak immune system, especially in children, pregnant women, the elderly are particularly vulnerable to electromagnetic waves, the situation that needs a solution to these damages.

At present, electromagnetic shielding technologies for protecting human body and various devices are spurring the development of electromagnetic shielding technology in various fields including chemical engineering beyond electronic information field.

Electromagnetic shielding refers to shielding of electromagnetic interference incident from the outside. Electromagnetic waves are reflected or absorbed and extinguished when they meet a material in progress. The degree is related to the conductivity of the material. The Shielding Effectiveness (SE) is a combination of the reflection and absorption capabilities of shielding materials. And absorption capacity is increased.

It is therefore advantageous for the electromagnetic shielding material to be electrically conductive and to have a large surface area. Conventionally, metals such as copper, iron, nickel, aluminum, tin, and zinc, which have good electromagnetic properties, have been spotlighted as shielding materials. However, metals are generally heavy, have poor workability, and cause corrosion. As regulations increase, new shielding materials are required that are safer, greener and more economically competitive.

According to the above situation, the present inventors first paid attention to the principle of microwave oven as a shielding material. Microwave, which is an area of electromagnetic waves used in microwave ovens, passes through the wave without being affected by materials such as glass, paper, and plastic, Food is heated and cooked on the principle of being absorbed by constituent water molecules or other molecules such as fat and sugar. In addition, articles on radiocommunication disturbances due to electromagnetic interference at sea are often available. This gave us the idea that water would be effective as an electromagnetic shielding material.

In the present invention, the environmentally friendly agar and / or konjac made of mostly water was prepared in order to directly check the electromagnetic shielding effect by utilizing water as a solid. Since the materials are inexpensive, easy to process, and environmentally friendly, they can secure the disadvantages of the conventional electromagnetic shielding material.

In addition, in order to increase the electromagnetic shielding performance, a method of increasing the shielding effect by adding a carbon material decorated with AgSnO _{2, which} is used as the main material of the electromagnetic shielding material, was examined. Among the metals with excellent electrical properties, silver has excellent properties, but was heavy, bad workability, and costly. However, developing polymer composite materials with conductivity can solve these problems, and development of electrically conductive polymer-based shielding materials has excellent mechanical strength. In addition, since the manufacturing process is simple and the weight reduction efficiency is excellent, the present invention leads to the production of an electromagnetic wave shielding material based on carbonaceous material.

The electromagnetic shielding performance is generally expressed in dB (decibel), and it can be variously implemented from 0 to 70 dB with a polymer composite material.

For example, in US Patent Publication No. 2006-0099403, a composite was made of an electromagnetic shielding material consisting of a heat conductor and a magnetic material, and used as a heat conducting material between a semiconductor chip and a heat dissipation heat sink. The thermal conductor and the electromagnetic shielding material are dispersed in the matrix as small particles to shield the thermally conductive electromagnetic waves.

US Patent Publication No. 2016-0233173 discloses an electromagnetic wave shielding material dispersed in a polymer matrix including alumina particles having thermal conductivity, carbonyl iron powder, and silicon carbide as an electromagnetic wave shielding material, thereby improving thermal conductivity while maintaining electromagnetic wave shielding rate. Improved electromagnetic shielding efficiency.

However, with increasing interest in environmental issues around the world, attention has been paid to environmentally friendly materials with electromagnetic shielding performance. In the present invention, eco-friendly water and natural materials are used in the present invention, and AgSnO ₂ is decorated here. The carbon material (hereinafter referred to as " AgSnO ₂ -carbon material ") was added to confirm that the shielding performance of the electromagnetic wave shielding material using the water and natural materials can be significantly increased, and the present invention was achieved.

United States Patent Application Publication No. 2006-0099403 United States Patent Application Publication No. 2016-0233173

An object of the present invention is to provide a high electromagnetic shielding performance by adding AgSnO ₂ -carbon material to the environmentally friendly agar and / or konjac-based electromagnetic shielding material.

In addition, the purpose of providing a simple manufacturing method using a material that can be easily encountered in everyday life in providing the electromagnetic shielding performance.

In accordance with the above object, the present invention provides an electromagnetic shielding composition comprising water contained in at least one selected from agar and konjac, and further comprises an AgSnO ₂ -carbon material.

In a preferred embodiment of the present invention, the carbon material is graphite (graphite), graphite oxide (Graphite oxide), expanded graphite (Expanded graphite), graphene (Graphene), graphene oxide (Graphene oxide), graphene nanoplates (Graphene nano plate), carbon nanotubes (Carbon nanotube), may be one or more selected from the group consisting of carbon fibers (Carbon fiber).

In a preferred embodiment of the present invention, the composition of the electromagnetic wave shielding material provides an electromagnetic wave shielding material comprising 1 to 20 parts by weight of agar and / or konjac, relative to 100 parts by weight of water.

In a preferred embodiment of the present invention, the content of the AgSnO ₂ -carbon material of the composition of the electromagnetic wave shielding material provides an electromagnetic wave shielding material containing 0.1 to 30 parts by weight, relative to 100 parts by weight of water.

In addition, in a preferred embodiment of the present invention, the method for producing AgSnO ₂ -carbon material, (a) dispersing the carbon material in a solution prepared by adding a tin precursor and an acid solution to water to prepare a mixed solution; (b) adding ammonia to the mixed solution of step (a) and stirring for a predetermined time, followed by filtration and washing; (c) drying the resultant of step (b) to obtain a carbon material decorated with SnO ₂ ; (d) adding the SnO ₂ decorated carbon material and Ag precursor into water, mixing the mixture for a predetermined time, and then filtering and washing; (e) drying the resultant of step (d) to obtain an AgSnO ₂ -carbon material; (f) adding and dispersing the AgSnO ₂ -carbon material to water; (g) adding agar and / or konjac to the solution of step (f) and stirring and mixing while heating.

In addition, in a preferred embodiment of the present invention, the heating temperature in the step (g) is characterized in that it is carried out in the range of 80 ~ 95 ℃.

In addition, according to a preferred embodiment of the present invention, an electromagnetic wave shielding material including the electromagnetic wave shielding composition is provided.

The electromagnetic wave shielding composition and the electromagnetic wave shielding material manufactured using the same according to the present invention have an advantage of being harmless to the human body and being environmentally friendly because water contained in the network of the gel using the agar and / or konjac generates an electromagnetic shielding effect. .

In addition, AgSnO ₂ -carbon material is added to improve the shielding efficiency of the existing electromagnetic shielding material has the advantage of having excellent electromagnetic shielding performance.

1 is a flowchart for manufacturing the electromagnetic shielding material of the present invention.
2 is a transmission electron microscope photograph of the structure of the agar for absorbing and shielding electromagnetic waves according to an embodiment of the present invention.
3 is a graph showing the electromagnetic wave shielding result of the agar for absorbing and shielding electromagnetic waves according to an embodiment of the present invention.

Hereinafter, preferred embodiments of environmentally friendly electromagnetic shielding materials using agar and / or konjac according to the present invention will be described in detail. The terms or words used below should not be construed as being limited to the common or dictionary meanings, and include anything in the technical scope that is substantially the same as the technical idea and achieves the same effect.

In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The agar and / or konjac referred to in the present invention means a material having a three-dimensional network structure capable of swelling by containing a large amount of water therein in an aqueous solution as a crosslinked hydrophilic material.

The composition of the electromagnetic wave shielding material of the present invention is characterized in that it further comprises AgSnO ₂ -carbon material in water and agar and / or konjac.

The electromagnetic shielding composition comprises an electromagnetic shielding composition, characterized in that it comprises 1 to 20 parts by weight of agar and / or konjac, 0.1 to 30 parts by weight of AgSnO ₂ -carbon material, relative to 100 parts by weight of water.

The agar and / or konjac is a substance that forms a network and can swell by absorbing large amounts of water.

The AgSnO ₂ -carbon material is added to enhance the electromagnetic shielding effect.

The AgSnO ₂ decorated carbon composite material can be used as long as it has a material having an electromagnetic shielding effect, and, without limitation, graphite, graphite oxide, expanded graphite, graphene, Graphene oxide (Graphene oxide), graphene nano plate (Graphene nano plate), carbon nanotube (Carbon nanotube), carbon fiber (Carbon fiber) and the like can be used. Also, graphene is preferably used.

When carbon is applied as a material with high electrical conductivity, less corrosion and weight reduction are possible, and electromagnetic shielding efficiency can be improved.

In addition, the present invention may further comprise a curing aid in the electromagnetic shielding composition, the curing aid is used to enhance the strength to maintain the three-dimensional network structure of the agar and / or konjac.

The curing aid is preferably used 1 to 20 parts by weight with respect to 100 parts by weight of water, it is possible to improve the physical strength and mechanical strength compared to the existing agar or konjac within the above range.

Examples of the curing aid include high molecular materials such as resorcinol resins, phenolic resins, phenolic acid polymers, monosaccharides, disaccharides, polysaccharides, and the like. have.

The monosaccharides are glucose, fructose, galactose, and the like, and the disaccharides are sucrose, lactose, maltose, trehalose, and melibiose. , Cellobiose and the like, and polysaccharides include raffinose, melezitose, maltoriose, starchose, schrodese, starch, and resident starch. (resistant starch), glycogen, dextrin, oligosaccharides, cellulose, fructan, galactan, mannan, alginic acid ), Carrageenana (carragennana), chitin (chitin), lignin (Lignin), hemicellulose (hemicellulose), pectin (pectin) and the like, one or more of these may be used.

The electromagnetic wave for the purpose of blocking herein is an electromagnetic wave generated in an electronic / communication device that is used in daily use, an electromagnetic wave in a region of 10 ¹⁴ Hz or less, preferably an electromagnetic wave in a region of 10 ¹¹ Hz or less, and more preferably 20 GHz or less. It is aimed at shielding electromagnetic waves.

Next, the manufacturing method of the electromagnetic wave shielding material which concerns on this invention is demonstrated. First, in order to manufacture the electromagnetic wave shielding material of the present invention, AgSnO ₂ -carbon material should be manufactured.

The AgSnO ₂ -carbon material manufacturing method comprises the steps of: (a) preparing a mixed solution by dispersing the carbon material in a solution prepared by adding a tin precursor and an acid solution to water; (b) adding ammonia to the mixed solution of step (a) and stirring for a predetermined time, followed by filtration and washing; (c) drying the resultant of step (b) to obtain a decorated carbon material Sn; (d) adding Sn-decorated carbon material and Ag precursor to water, mixing the mixture for a predetermined time, and then filtering and washing; (e) drying the resultant of step (d) to obtain an AgSnO ₂ -carbon material; (f) adding and dispersing the AgSnO ₂ -carbon material to water; (g) adding agar and / or konjac to the solution of step (f) and stirring and mixing while heating; to prepare.

The tin precursor used in the step (a) is preferably selected from the group formed by the halogenated compound, hydroxide, carbonate, carboxylate, lactate and nitrate of tin (Sn), preferably using SnCl ₂ .2H ₂ O. Can be. The input amount of the tin precursor is used by weighing so that the content of tin is 5wt% to 40wt% relative to the carbon material.

The Ag precursor used in step (d) may be at least one selected from the group consisting of a halogenated compound of silver (Ag), a hydroxide, a carbonate, a carboxylate, a lactate and a nitrate, preferably AgNO ₃ . The Ag precursor is used to be weighed so that the Ag content is 0.05 to 0.2 (mol ration) compared to the carbon material.

The drying temperature in the step (e) is carried out at 80 ℃, the heating temperature in the step (g) may be carried out in the temperature range of 80 ~ 95 ℃, preferably 85 ~ 90 ℃, mixing Is stirred for 1-2 hours. The resulting product after step (g) is used after cooling to room temperature.

Steps (f) and (g) may be performed separately as described, and AgSnO ₂ -carbon material and agar and / or konjac may be simultaneously added to water.

In FIG. 1, a process of synthesizing AgSnO ₂ -Graphene in the manufacture of the electromagnetic wave shielding material is shown in a flowchart.

_{2 shows an} AgSnO ₂ -Graphene transmission electron microscope image prepared by the above method.

Hereinafter, the embodiment will be described for a more detailed description of the present invention. However, the following examples are only preferred examples of the present invention and the present invention is not limited to the following examples.

<AgSnO ₂ -Graphene production>

4 ml HCl aqueous solution (35%) and 10 g SnCl ₂ were added to 400 ml of water to form a SnCl ₂ aqueous solution, and 1 g of Graphene was dispersed and stirred for 12 hours. Sn coated Graphene was washed and dried in a 60 degree oven for 12 hours. AgNO ₃ Ag-coated Graphene was dispersed in a 5wt% aqueous solution to reduce Ag on the graphene surface, washed, and dried again in an oven at 60 degrees for 12 hours to prepare AgSnO ₂ -Graphene.

<Examples 1-4>

AgSnO ₂ -Graphene and 1.25 g of agar powder were added to 100 g of water, and then dispersed in 300 W for 20 minutes using an ultra sonicator. The dispersion was heated to 80 ° C. and stirred and mixed for 1 hour or more. After cooling to a temperature below room temperature and the results according to the type of filler are shown in Table 1 below.

division Water (g)
additive

Agar (g)

Filler Content (g)
Comparative Example 1

100
1.25
-
Example 1

100
1.25
0.5 (graphene)
Example 2

100
1.25
0.5
(Silver decoration graphene)

Experimental Example 1

The electromagnetic wave shielding efficiency of the electromagnetic wave shielding composition prepared according to Examples 1 to 3 was analyzed using the GPC-7 accessory to the Vector Network Analyzer in the 2-18 GHz frequency band. When the EMI SE value representing the electromagnetic shielding performance is 25 dB or more in the frequency band, it can be regarded as excellent as a shielding material and the measurement results according to the hydrogel are shown in Table 2.

Comparative example

Example 1
Example 2
EMI SE (dB)

25
30-40
35-60

As shown here, it was confirmed that the performance of the electromagnetic wave shielding material added AgSnO ₂ -carbon material was improved, through which the effect of improving the efficiency of the electromagnetic shielding material is preferable.

Having described the specific part of the present invention in detail, it will be apparent to those skilled in the art that the specific description is only a preferred embodiment, and thus the scope of the present invention is not limited thereto. will be. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (8)

(a) adding AgSnO ₂ -carbon material and agar and / or konjac together in water or dispersing AgSnO ₂ -carbon material in water and then adding agar and / or konjac to prepare a dispersion;
(b) stirring and mixing the dispersion while heating at a temperature in the range of 80-95 ° C .; And
(c) after step (b), cooling to prepare an electromagnetic wave shielding composition;
The carbon material is graphite, graphite oxide, expanded graphite, graphene, graphene oxide, graphene nano plate, carbon nanotube (Carbon nanotube), Carbon fiber (Carbon fiber) characterized in that at least one member selected from the group consisting of, a method for producing an environmentally friendly electromagnetic shielding composition including AgSnO ₂ -carbon material. The method of claim 1,
The prepared electromagnetic shielding composition is compared to 100 parts by weight of water, agar and / or konjac contains 1 to 20 weights, AgSnO ₂ -carbon material, characterized in that containing 0.1 to 30 parts by weight, AgSnO ₂ -carbon Method for producing an environmentally friendly electromagnetic shielding material composition comprising a material. The method of claim 1,
Preparation of the AgSnO ₂ -carbon material,
(a) dispersing a carbon material in a solution prepared by adding a tin precursor and an acid solution to water to prepare a mixed solution;
(b) adding ammonia to the mixed solution of step (a) and stirring for a predetermined time, followed by filtration and washing;
(c) drying the resultant of step (b) to obtain a decorated carbon material Sn;
(d) adding Sn-decorated carbon material and Ag precursor to water, mixing the mixture for a predetermined time, and then filtering and washing; And
(e) drying the resultant of step (d) to obtain an AgSnO ₂ -carbon material; characterized in that it comprises a, AgSnO ₂ -carbon material manufacturing method of an environment-friendly electromagnetic shielding material composition comprising a. The method of claim 1,
The prepared electromagnetic shielding composition is characterized in that the EMI SE in the frequency band of 2 ~ 18 GHz 35-60 dB, a method for producing an environmentally friendly electromagnetic shielding composition including AgSnO ₂ -carbon material. Electromagnetic wave shielding material formed from the electromagnetic wave shielding material composition manufactured by the method of any one of Claims 1-4.

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