KR20130010285A

KR20130010285A - Carbon nanomaterial coated electromagnetic interference shielding composites and preparation method thereof

Info

Publication number: KR20130010285A
Application number: KR1020110070989A
Authority: KR
Inventors: 박영빈; 공조엘; 김명수; 박형욱; 정호순
Original assignee: 정호순
Priority date: 2011-07-18
Filing date: 2011-07-18
Publication date: 2013-01-28

Abstract

The present invention relates to a composite material for shielding electromagnetic waves coated with carbon nanomaterials and a method for manufacturing the same. More specifically, a mixing step of mixing a carbon nanomaterial in methanol, and a coating for coating the surface of the insulating fiber with the carbon nanomaterial described above. In the step, the coating step comprises the step of injecting a polymer resin into a carbon nanomaterial coated insulating fiber using a VARTM molding machine.

Description

Carbon nanomaterial coated electromagnetic shielding composite and manufacturing method {Carbon Nanomaterial Coated Electromagnetic Interference Shielding Composites and Preparation Method Thereof}

The present invention relates to a composite material for shielding electromagnetic waves coated with carbon nanomaterials and a method of manufacturing the same. More specifically, the carbon nanomaterial is formed by vacuum injection of a polymer resin into a substrate of an insulating fiber coated with carbon nanomaterial. The present invention relates to a coated electromagnetic shielding composite and a method of manufacturing the same.

Recently, with the rapid development of computers, electronics, communication devices, and the like, the use of electromagnetic waves has increased due to the mass distribution, and the occurrence of electromagnetic noises in various frequency ranges has increased rapidly. In addition, research and development of electromagnetic shielding materials have been actively conducted as a solution for effectively minimizing electromagnetic pollution according to the low power and high integration of electronic devices and circuits in various electronic devices. The main variables that determine the electromagnetic shielding performance are the basic physical properties of the material (complex dielectric constant and complex permeability), the resistance in a specific frequency band and the thickness of the shielding material, the electromagnetic shielding effect in a uniform conductor is Can be represented.

SE (dB) = A + R + B

Where SE is the total electromagnetic shielding performance, A is the amount of electromagnetic wave energy absorption, R is the amount of electromagnetic wave energy reflection, and B is the composite reflection factor.

Electromagnetic shielding materials include carbon materials, ceramics, and composite materials in which metal fillers such as aluminum, iron, and copper are added to existing polymer resins, but generally carbon materials such as carbon black, graphite, and carbon fiber, ferrite, silica, etc. Ceramic materials tend to absorb electromagnetic waves in a specific frequency region, and metal materials and the like have characteristics of scattering electromagnetic waves.

As a method of adding a filler to the polymer resin, there is a method of forming a dielectric layer by coating the surface of the molded substrate, or molding through suitable curing conditions after dispersion and mixing with the polymer resin. The dielectric layer formed on the surface of the molded article by the former method is made of conductive paints such as nickel, copper, silver / copper, silver or carbon black and graphite powder together with resins for bonding acrylic, acrylic / urethane, urethane, epoxy, etc. The dielectric layer is formed by coating on the surface of the polymer substrate and then drying or by metal spraying, vapor deposition, sputtering, or the like.

In the latter method, a conductive material is directly applied to a molded product, and the metal material such as copper or silver, fibrous, granular or fine powder carbon black, carbon fiber, etc. are directly mixed and dispersed in various polymer resins such as thermoplastic, thermosetting and rubber and cured. Let's do it.

The conventional shielding material has a limitation in the content of the carbon material due to the sharp increase in the viscosity of the polymer resin according to the addition amount of the carbon material added to the polymer resin, there is a problem that can not control the content of the carbon material added to the polymer resin.

The present invention is to solve the above problems, the mixing step of mixing the carbon nano material in methanol, the coating step of coating the carbon nano material on the surface of the insulating fiber, and the carbon nano material is coated in the coating step Injecting a polymer resin into the insulating fiber using a VARTM molding machine; provides a method for producing a composite material for electromagnetic wave shielding coated with carbon nanomaterial.

The insulating fiber is characterized in that it consists of any one of glass fiber, Kevlar fiber, ultra high molecular weight polyethylene (UHMWPE).

The carbon nanomaterial is made of any one of multi-walled carbon nanotubes, graphene (Graphene), exfoliated graphite nanoplatelet.

Carbon nano material coated on the surface of the insulating fiber in the mixing step is characterized in that 1g / L is mixed in methanol.

The thickness of the carbon nano material coated on the surface of the insulating fiber in the coating step is characterized in that 1.5 ~ 2.0μ.

According to an embodiment of the present invention, after coating the carbon nanomaterial on the surface of the insulating fiber through an ultrasonic disperser, a polymer resin is injected into the insulating fiber coated with the carbon nanomaterial using a VARTM molding machine to produce an electromagnetic shielding composite material. By manufacturing, there is an effect that can effectively control the content of the carbon nano material.

1 is a manufacturing process diagram of the electromagnetic shielding composite coated with carbon nanomaterial according to an embodiment of the present invention.
Figure 2 is a cross-sectional view of the electromagnetic shielding composite coated with carbon nanomaterials according to each embodiment of the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation.

In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or convention of a user or an operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

1 is a manufacturing process chart of the carbon nano-material coated electromagnetic shielding composite according to an embodiment of the present invention, Figure 2 is a carbon nano-material coated electromagnetic shielding composite according to each embodiment of the present invention It is a cross section of.

1 to 2, a method of manufacturing a fiber-reinforced composite material for electromagnetic wave shielding by coating carbon nanomaterials according to an embodiment of the present invention comprises the steps of mixing the carbon nanomaterial 10 in methanol (S10) and In the coating step (S20) for coating the carbon nano material 10 on the surface of the insulating fiber 12, and in the coating step (S20) to the insulating fiber 12 coated with the carbon nano material (10) VARTM molding machine Injecting the polymer resin using the step (S30) is made.

In the mixing step (S10), the carbon nano material 10 is mixed with methanol at 1 g / L.

In the coating step (S20), the carbon nanomaterial 10 mixed with methanol in the mixing step (S10) is dispersed for 30 minutes using an ultrasonic disperser (not shown). Thereafter, the dispersed carbon nanomaterial 10 is sprayed onto the surface of the insulating fiber 12 through a spray gun (not shown) and coated.

At this time, the pressure of the spray gun (not shown) is 2-3 kgf / cm ² Preferably, the thickness of the carbon nanomaterial 10 coated on the surface of the insulating fiber 12 is preferably 1.5 ~ 2.0μ.

Here, the carbon nano material 10 is preferably made of any one of a multi-walled carbon nanotube, graphene, exfoliated graphite nanoplatelet.

In the polymer resin injection step (S30), the polymer resin is injected into the insulating fiber 12 coated with the carbon nanomaterial 10 using a VARTM molding machine (not shown).

Here, the insulating fiber 12 is preferably made of any one of glass fiber, Kevlar fiber, ultra high molecular weight polyethylene (UHMWPE).

Hereinafter, a method for producing a composite material for electromagnetic shielding coated with carbon nanomaterials according to the present invention and an electromagnetic shielding effect will be described with reference to Examples.

&Lt; Example 1 >

The carbon nanomaterial was mixed in methanol at 1 g / L, the carbon nanomaterial mixed with methanol was dispersed for 30 minutes using an ultrasonic disperser, and the dispersed carbon nano material was sprayed using a spray gun at 2 to 3 kgf / cm ^2. The coating was sprayed on the surface of the insulating fiber under pressure, and a polymer resin was injected into the insulating fiber coated with the carbon nanomaterial using a VARTM molding machine to prepare a carbon nanomaterial coated electromagnetic shielding composite.

Proceed in the same manner as in Example 1, the carbon nano material is coated to concentrate in the center, and the carbon nano material is coated with carbon resin by injecting a polymer resin into the insulating fiber coated with the carbon nano material concentrated in the center using a VARTM molding machine. Shielding composites were prepared.

Proceed in the same manner as in Example 1, the carbon nano material is dispersed and coated, and the carbon nano material coated electromagnetic shielding composite material by injecting a polymer resin into the insulating fiber coated with the carbon nano material dispersed using a VARTM molding machine Prepared.

&Lt; Comparative Example 1 &

Polymeric resin was injected using an insulating fibre VARTM molding machine to prepare an electromagnetic shielding composite material.

The electromagnetic wave shielding efficiency for each frequency band of the carbon nanomaterial-coated electromagnetic shielding composite prepared in Examples 1 to 3 and Comparative Example 1 was measured and shown in the following graph 1.

Here, the electromagnetic shielding efficiency of each frequency band was measured by Rhode &Schwarts' Shield effective test system (Daegu Nano Convergence Center).

As shown in the graph 1 above, the carbon nanomaterial coated electromagnetic shielding composite prepared in Examples 1 to 3 of the present invention is significantly improved in electromagnetic shielding efficiency compared to the electromagnetic shielding composite prepared in Comparative Example 1. It can be seen that.

In addition, it can be seen that when the same amount of carbon nanomaterial is coated on the insulating fiber, it is more effective to concentrate the electromagnetic shielding efficiency than to disperse it.

Although the preferred embodiments of the present invention have been described with reference to the accompanying drawings, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the invention It can be understood that it is possible.

S10; Mixing stage
S20; Coating step
S30; Polymer resin injection step
10; Carbon Nano Material
12; Insulating fiber

Claims

Mixing the carbon nanomaterial with methanol;
A coating step of coating the carbon nanomaterial on the surface of the insulating fiber; And
And injecting a polymer resin into the insulating fiber coated with the carbon nanomaterial in the coating step by using a VARTM molding machine.

The method according to claim 1,
The insulating fiber is a method of manufacturing a composite material for electromagnetic wave shielding composite coated with carbon nano material, characterized in that made of any one of glass fiber, Kevlar fiber, ultra high molecular weight polyethylene (UHMWPE).

The method according to claim 1,
The carbon nano material is a multi-walled carbon nanotubes, graphene (graphene), a method for producing a composite material for electromagnetic wave shielding composites characterized in that the carbon nano material is made of any one of (exfoliated graphite nanoplatelet).

The method according to claim 3,
Carbon nano material coated on the surface of the insulating fiber in the mixing step is a method for producing a composite material for electromagnetic wave shielding composites, characterized in that 1g / L is mixed in methanol.

The method according to claim 3,
The thickness of the carbon nano material coated on the surface of the insulating fiber in the coating step is 1.5 ~ 2.0μ coated carbon nano material is a method for manufacturing a composite for electromagnetic wave shield composite.

Electromagnetic shielding composite produced by the manufacturing method of any one of claims 1 to 5.