KR20210021810A - Electromagnetic sheilding Clothing - Google Patents

Abstract

The present invention relates to clothes having an electromagnetic wave shielding function, and more particularly, to clothes in which a sheet having an electromagnetic wave shielding function is attached to the same. According to the present invention, it is possible to obtain the electromagnetic wave shielding sheet capable of effectively blocking electromagnetic waves, and electromagnetic wave shielding clothing which applies at least a part of the electromagnetic wave shielding sheet.

Description

Electromagnetic sheilding clothing

The present invention relates to clothing having an electromagnetic wave shielding function, and more particularly, to a clothing having a sheet having an electromagnetic wave shielding function attached thereto.

Modern society is exposed to electromagnetic waves to the extent that it is not an exaggeration to say that it is a flood of electromagnetic waves.

Electromagnetic waves are a phenomenon in which energy moves in the shape of a sinusoidal wave while an electric field and a magnetic field interwork with each other, and are usefully used in electronic devices such as wireless communication and radar. The electric field is generated by a voltage and is easily shielded by an obstacle such as a tree or a distance being increased, while the magnetic field is generated by an electric current and is inversely proportional to the distance, but is not easily shielded.

On the other hand, recent electronic devices are sensitive to electromagnetic interference (EMI) generated by an internal interference source or an external interference source, and there is a concern that a malfunction of the electronic device may be caused by electromagnetic waves. In addition, users who use electronic devices may also be adversely affected by electromagnetic waves generated from the electronic devices.

Accordingly, in recent years, interest in electromagnetic wave shielding for protecting parts of electronic devices or a human body from electromagnetic wave generation sources or electromagnetic waves radiated from the outside has increased rapidly.

The electromagnetic wave shielding is typically made of a conductive material, and the electromagnetic wave is typically reflected or ground again to shield the electromagnetic wave. On the other hand, the electromagnetic waves may be shielded by a metal plate, etc., and such a plate-shaped electromagnetic wave shielding material is difficult to develop elasticity, and once manufactured, it is not easy to transform/restore into various shapes, so it is easily adopted for various applications. There is a problem that is difficult to become. Particularly, since the electric wave shielding material such as a metal plate or a metal thin film may crack due to bending or bending, it may be difficult to fully express the electromagnetic wave shielding performance when applied to clothes or the like.

In order to solve this problem, recently, an electromagnetic shielding material in which a conductive coating layer is formed on a lightweight support member such as a polymer film has been introduced, but there is a limit to the electromagnetic shielding performance according to the limitation of the area that can be coated on the support member. Films with a certain thickness or more are difficult to apply to clothing due to lack of flexibility, and it may be difficult to freely transform the shape after being manufactured into a specific shape. Even if the shape is deformable, the coated conductive coating layer cracks during shape deformation. , There is a problem that peeling occurs frequently. Accordingly, there is a demand for a material that is light, excellent in flexibility, and excellent in shielding performance that can be applied to clothes or the like.

Accordingly, in order to solve the above-described problems, the present inventor is to provide a lightweight, flexible, and excellent shielding material that can be applied to clothes and the like, and electromagnetic wave shielding clothing to which the same is applied.

In order to solve the above-described problem, the present invention provides an electromagnetic wave shielding sheet to which a silver nano paste is applied, and an electromagnetic wave shielding clothing to which the sheet is attached.

According to an embodiment of the present invention, the electromagnetic wave shielding sheet is characterized in that it includes a coating using a silver nano paste on a polymer resin fiber.

According to an embodiment of the present invention, the silver nano paste is characterized in that it contains silver nano particles as a filler and a urethane resin as a binder.

According to an embodiment of the present invention, the silver nano paste has a size of 1 to 1000 nm and contains 10 to 30% by weight of silver nanoparticles having a purity of 99.9% or more.

According to another embodiment of the present invention, the polymer resin fiber is one selected from the group consisting of PVDF (polyvinylidene fluoride) resin, PPV (poly [p-phenylene vinyl]) resin, and urethane resin. It may be formed of a fiber-forming component including the above. The fiber-forming component may include PVDF-based resin, PPV-based resin, and urethane-based resin in a weight ratio of 1: 0.43 to 2.35.

According to another embodiment of the present invention, the polymer resin fiber may be a nanofiber web. The nanofiber web may be prepared by electrospinning a spinning solution containing a fiber-forming component, a solvent, and metal particles. The fiber-forming component may include PVDF-based resin, PPV-based resin, and urethane-based resin in a weight ratio of 1: 0.43 to 2.35.

According to another embodiment of the present invention, the nanofibers may have an average diameter of 150 nm to 5 μm. The nanofiber web may have a thickness of 4 to 30 μm and a basis weight of 3.00 to 20.00 g/m 2. In addition, the conductive nanofiber web may have a porosity of 30 to 80%.

According to the present invention, it is possible to obtain an electromagnetic wave shielding sheet capable of effectively blocking electromagnetic waves, and an electromagnetic wave shielding clothing in which the same is applied to at least a part.

1 is a diagram showing an electrospinning method for manufacturing nanofibers.
2 is an electron microscope image of a nanofiber web.
3 is a graph showing an electromagnetic shielding effect of the electromagnetic shielding sheet according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily implement the present invention. Embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art. Accordingly, embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

Throughout the specification of the present invention, when a certain part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

Throughout the specification of the present invention, when a step is positioned "on" or "before" another step, it is not only the case that a step is in a direct time series relationship with the other step, but also the mixing step after each step and Likewise, the order of the two steps can contain the same rights as in the case of an indirect time-series relationship that can change the time-series order.

The terms "about", "substantially", etc. of the degree used throughout the specification of the present invention are used at or close to the numerical value when manufacturing and material tolerances specific to the stated meaning are presented, and the present invention To aid in understanding of, accurate or absolute figures are used to prevent unreasonable use of the stated disclosure by unscrupulous infringers. As used throughout the specification of the present application, the term "step (to)" or "step of" does not mean "step for".

Recently, as the awareness of the harm of electromagnetic waves has increased, research on various materials having an electromagnetic wave shielding function has been conducted, and as a material having mainly electrical conductivity, the electromagnetic waves are usually reflected back or ground to shield the electromagnetic waves.

In the present invention, silver (Ag) is used as an electrically conductive material for shielding electromagnetic waves, and specifically, a fiber coated with a silver nano paste on a polymer resin fiber is used.

The conductive paste is usually prepared by mixing a coating film forming agent (binder) and a metal powder. As a coating film forming agent, liquids such as epoxy, linseed oil, soybean oil, lacquer, tung oil, synthetic dry oil, etc. using crosslinking properties, natural resins such as shellac and copal, processed resins such as lime rosin, phenolic resin, urea resin, melamine resin , Synthetic resin such as vinyl resin, cellulose derivatives such as nitrocellulose, acetyl cellulose, rubber derivatives such as synthetic rubber, and solids such as polyvinyl alcohol and casein are dissolved in a solvent. In the conductive paste, a mixture of a low melting point glass powder and an organic compound is sometimes used as a coating film forming agent. When a sufficient amount of metal powder is added to the coating film forming agent and mixed, particles of the metal powder contact each other to form a conductive paste having a property of conducting electricity. The types of metal powders commonly used in the manufacture of conductive pastes include gold, silver, platinum, palladium, copper, etc., which have high electrical conductivity. Gold, silver, platinum, and palladium have high corrosion resistance and good electrical conduction, but are very expensive. Phosphorus has a disadvantage, and copper has the advantage of being inexpensive and conducting electricity well, but its corrosion resistance is low, and the surface of the powder particles easily changes to an oxidized layer due to moisture in the air, so that electricity does not pass well even if the powders come into contact with each other. In order to compensate for such shortcomings of copper, silver is plated on the surface of the copper powder particles. However, since the manufacturing cost is increased, the inexpensive advantages of copper are lost. Most of the conductive inks so far have been developed mainly using silver as a conductive material, and some developed products use carbon nanotubes. The reason that silver is mainly used is because silver shows the best electrical conductivity among metals, is relatively easy to obtain, and can be obtained at a lower cost than carbon nanotubes.

On the other hand, nanofiber is a material that exhibits high performance throughout the industry, and the application of nanomaterials such as filters using nonwoven fabrics, miniaturization of electronic devices, high functionality, and use of biological tissues is increasing, and it is also highly functional in traditional industries such as machinery and chemical industries. The application of nanomaterials for this is gradually increasing. Accordingly, high-functional nanofibers are expected to grow high in the future as demand increases.

Nanofibers can be mainly manufactured by field spinning, and this field spinning method discovered in 1795 that when Bose applied a high voltage to a water drop suspended at the end of a capillary tube, an electrostatic spray phenomenon in which fine filaments were released from the water drop surface due to surface tension. It started with, and it is a phenomenon in which fibers are formed when electrostatic force is applied to a polymer solution or melt having a viscosity. The diameter of the fiber produced by electric field spinning can produce a wide range of fibers ranging from small-thick fibers consisting of polymer chains of 10 or less per cross-sectional area to the thickness of conventional textile fibers, and will continue to be demanded in the fields of nanoscience, material science, and life science. Is expected to increase rapidly.

Nanomaterials have dimensions of at least 100 nm or less, and in the case of textile fibers, they can be defined as one-dimensional flexible solid-state nanomaterials having a diameter of 100 nm and an aspect ratio of 100:1 or more. Microfiber is a fiber that has been contracted and processed thinner than one hundredth of the thickness of a human hair, and has been used as the term microfiber. In recent years, as the technology related to nanomaterials rapidly develops, fiber materials that are thinner and thinner than existing microfibers are being developed, and recently, fibers with a thickness of 1micrometer or less are being used as a new standard for microfibers, and this is called nanofibers.

The nanofiber manufacturing technology directly manufactures fibers having a nano-sized fiber diameter, and is manufactured by composite spinning, nonwoven spinning, and direct spinning. By controlling the size of the fiber to a nano size, existing functions can be greatly improved, and its use is expanding not only for clothing, but also for filters, energy storage materials, and medical use. Nanofiber refers to a fiber with a diameter of 1 nm to 100 nm in a strict sense, but the use of such fiber is extremely limited in the textile industry, so the diameter of the fiber is 1 for differentiation from microfibers called microfibers. It refers to fibers that are less than or equal to µm. The recently mentioned nanofiber generally refers to a fiber manufactured by electrospinning or an improved method, and can be largely divided into a nanospinning field and a nanostructured fiber field according to a manufacturing method. In general, the thinner the fiber, the lower the productivity.

Electrospinning is a method of manufacturing using the difference in charge, and is attracting attention as a technology capable of manufacturing ultra-fine polymer fibers that cannot be processed by other methods. It is a relatively simple and easy way to produce fibers with nanometer to submicron diameter from solutions or melts of polymers, ceramics, composite materials, and metals. In the field-spinning device, at the end of a capillary tube positioned vertically, that is, at the spinning protrusion, the polymer solution equilibrates between gravity and surface tension to form hemispherical droplets and hang. At this time, when an electric field is applied, a force opposite to the surface tension is generated, and the hemispherical droplet is stretched in a conical shape, and when the electric field exceeds a certain strength, the jet of the charged polymer solution is continuously released from the Taylor cone while overcoming the surface tension. . In the case of electric field radiation, the cone angle is about 30 degrees. When a higher voltage is applied, jets are formed from the deformed droplets. This jet moves in the direction of the opposite electrode and becomes thinner. The solvent evaporates while heading to the counter electrode, and solid fibers with diameters ranging from micrometers to nanometers are precipitated as it is directed to the counter electrode at a high rate. The field spinning apparatus is very simple, but the mechanism of fiber spinning under the influence of an electric field is very complicated. The key to field emission is to create a continuous jet by immobilizing an electric charge on the surface of a suspended droplet. The field emission process can be divided into five main steps.

1) the addition of electric charges of the hanging droplets,

2) formation of a cone-jet,

3) thinning of the stabilizing jet,

4) reduction in diameter to nanometer size through growth of jet stability, and

5) Fiber collection in various forms.

After the unstable liquid filaments are stretched to form nanometer-sized fibers and solidify, fibers are accumulated on the collector. The liquid jet must maintain adequate viscoelasticity to maintain the fiber shape during spinning and stretching. Types of nanofibers include polymeric nanofibers, carbon nanofibers, and other nanofibers.

Polymer is the earliest developed nanofiber material, and started with the development of field spinning, the most common nanofiber manufacturing method at present. In the early 1980s, Donaldson produced the world's first field-spun nanofibers of 500 nm or less and applied it to the air filter market. Various polymers have been developed as raw materials, and most commercial polymers can be applied as nanofibers.

Carbon nanofibers have been developed by Radushkevich and Lukyanovich of Russia for the first time in 1952 when they first announced hollow carbon fibers with a diameter of 50 nm, and in 1976, Oberlin of France and Endo and Koyama of Shinshu University in Japan developed nano-scale carbon fibers through CVD process. I did. Since then, significant technological advances have been made in the United States and Japan.

In addition, various materials are being applied to others. In addition to polymers and carbon, ceramics, glass, metals, and composites thereof are applied as nanofibers, and are applied to almost all industrial fields.

Hereinafter, the present invention will be described in more detail through examples according to an embodiment of the present invention, but these do not limit the scope of the present invention.

[Example]

1. Silver nano paste manufacturing

To 70% by weight of a TPU binder, 19% by weight of ECA (2-(2-Ethoxyethoxy)ethyl Acetate), which is a high boiling point solvent, and 1% by weight of BYK's wetting and dispersing agent BYK-180, were added as an additive. Thereafter, the first mixing was completed with an impeller, and 20% by weight of silver nano powder was added in small portions, and further mixing was performed. Silver nano powder was used with a purity of 99.9% with an average particle diameter of 20 nm. The paste, in which the mixing of the silver nanopowder was completed, was further dispersed 5 times in a row with a 3-roll mill, and then stabilized with a ball mill for 24 hours.

2. Shielding sheet manufacturing

The silver nano paste was printed on polyethylene-based fibers to a thickness of about 20 μm by silk screen printing, and cured at 130° C. for 30 minutes with an oven dryer.

3. Electromagnetic wave shielding performance test

The electromagnetic shielding effect (SE) is defined as follows.

SE = 10 × log(P2/P1) [dB]

here,

P1 = received power with shield

P2 = received power without shielding

to be.

Accordingly, the shielding effect means, for example, 10dB = 90% shielding, 20dB = 99% shielding, 30dB = 99.9% shielding, and 40dB = 99.99% shielding.

The measurement device was Agilent's Network Analyzer. Measurement conditions were carried out in accordance with ASTM D4935-10, and the measurement frequency was measured over the range of 30MHz ~ 1.5GHz. As a result of the measurement, the maximum/minimum shielding effect was measured as follows, and a specific measurement value graph is shown in FIG. 3.

As the measurement results indicate, the electromagnetic wave shielding sheet according to the present invention exhibited a shielding effect (99.99% or more) in the range of 45 to 49 dB for electromagnetic waves in the range of 30 MHz to 1.5 GHz.

Claims (5)

Including a coating with a silver nano paste on the polymer resin fiber,
The silver nano paste is characterized in that it contains silver nano particles as a filler and a urethane resin as a binder,
The silver nano paste has a size of 1 to 1000 nm and contains 10 to 30% by weight of silver nanoparticles having a purity of 99.9% or more.
The method of claim 1,
The polymer resin fiber is formed of a fiber-forming component comprising at least one selected from the group consisting of PVDF (polyvinylidene fluoride) resin, PPV (poly [p-phenylene vinyl]) resin, and urethane resin. An electromagnetic wave shielding sheet, characterized in that.
The method of claim 1,
The polymer resin fiber is a nanofiber web formed of nanofibers and including a plurality of pores,
The nanofibers have an average diameter of 150 nm to 5 μm,
The nanofiber web has a thickness of 4 to 30 μm, a basis weight of 3.00 to 20.00 g/m 2, and a porosity of 30 to 80%.
The method of claim 1,
The nanofibers are formed of a fiber-forming component comprising at least one selected from the group consisting of PVDF (polyvinylidene fluoride) resin, PPV (poly [p-phenylene vinyl]) resin, and urethane resin, The fiber-forming component comprises a PVDF-based resin, a PPV-based resin, and a urethane-based resin in a weight ratio of 1: 0.43 to 2.35.
An electromagnetic shielding garment comprising at least a portion of the electromagnetic shielding sheet according to any one of claims 1 to 4 attached thereto.

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