KR20030096140A - The multi-layer type sheet for shielding from electromagnetic waves and the method for making it - Google Patents

Abstract

PURPOSE: A multi-layered conductive rubber sheet and a preparation method thereof are provided to shield the electromagnetic wave effectively and maintain the flexibility and tensile strength of the sheet well. CONSTITUTION: The multi-layered conductive rubber sheet comprises a conductive paste layer(1) to add 15 to 85 wt.% of the dendrite type, granule type and amorphous metal or metal components, the carbon black and the graphite to a resin selected from the group consisting of urethane, acrylics, PVC, polyesters, EPDM and silicone; a conductive rubber sheet layer(2) to add 15 to 85 wt.% of the dendrite type, granule type and amorphous metal or metal components, the carbon black and the graphite to a resin selected from the group consisting of urethane, acrylic, PVC, polyester, EPDM and silicone; and a conductive material layer(3) in a type of polyester fabrics, non-woven fabrics or mesh with a metal applied on.

Description

The multi-layer type sheet for shielding from electromagnetic waves and the method for making it}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer conductive rubber sheet having excellent electromagnetic wave shielding properties and a method of manufacturing the same, wherein the flake and dendrite type, the granule type, and the amorphous type (copper, nickel, silver, Conductive material consisting of a conductive paste layer comprising a metal or metal alloy of silver coated copper, carbon black, graphite, a conductive rubber sheet layer, and a conductive fabric, nonwoven fabric or mesh The present invention relates to a multi-layered sheet having excellent electromagnetic shielding performance in which layers form upper and lower layers, and a method of manufacturing the same.

That is, the conductive paste layer, the conductive rubber sheet layer, and a conductive material layer made of any one of a conductive fabric, a nonwoven fabric, or a mesh are formed to form a multi-layered sheet in which the upper and lower sides are joined, respectively, to effectively shield electromagnetic waves. It ensures excellent flexibility and tensile strength of the sheet.

The recent development of scientific civilization has provided many conveniences to human life. In particular, the development of electrical, electronic and communication-related equipment is playing a part in making our lives more convenient and profitable. The scientific civilization, which provides convenience to humans, has both sides which may be good or bad depending on how and where it is used.

One of the latest scientific literature that harms humans is electromagnetic waves. From the production and transmission of electricity, the communication of radios and TVs, telephones, to microwaves and ovens, to the space navigation of airplanes and ships, everything is unimaginable. As technology develops, electronics will pour and electromagnetic waves will increase.

Even now, electromagnetic waves wander around us as colorless and odorless, like the air we breathe. However, these electromagnetic waves, which are indispensable to humans, are also called electromagnetic interference (EMI), which disturbs other electromagnetic waves, causing malfunction of various machines, causing industrial accidents, and directly or indirectly affecting the human body. .

In addition, for example, the efficiency and lifespan of internal electronic products may be reduced due to the high voltage generator of the automobile, the disturbance between electronic equipments, glaucoma, which may occur in the case of long-term exposure to microwaves, and the reproductive ability may be reduced. The space inhabited by modern people is no longer a safe zone from electromagnetic waves, and as scientific civilization develops, its seriousness will increase.

The human body has a microscopic electronic signaling system that enables mechanisms of emotion regulation, memory, and behavior. Pregnancy, childbirth, illness and stress in human history would be shocking if they were never related to electromagnetic waves, but that is true. Under these circumstances, advanced countries such as the United States, Japan, and Russia have established safety exposure standards for electromagnetic waves to strongly regulate external exposure, and continue to study the harmfulness of electromagnetic waves.

In particular, in the advanced countries, more than 20 years have already been developed in the advanced countries to maintain the high-quality information and minimize the impact on the electromagnetic interference (EMI), which is generated in proportion to the rapidly increasing information and communication age in the 21st century. EMI has been regulated and in recent years, it has been very active in protecting the electromagnetic environment by forcing electromagnetic wave immunity.

In general, when a metal is used as a base material of a conventional EMI material, a polymer material is mainly used as a binder concept. A rubber system such as a silicone copolymer or a terpolymer of chlorinated polyethylene, chloro sulfonated polyethylene, ethylene propylene diene, and ethylene propylene copolymer Although it is used as a non-crosslinking type or a crosslinking type, the EMI material has a metal content of more than 70wt%, so that the composite which is simply mechanically mixed or blended (particularly in the case of thermoplastic) has almost no physical property ( Elongation 100% ~ 0%) The heat resistance is also very poor.

In the case of the crosslinking type, the heat resistance is improved, but since the metal and the polymer are basically in a state of mechanically mixing, there is a problem in that the physical properties of the material are not good, so that the basic physical properties of shielding the electromagnetic waves cannot be continuously maintained, but are cured or decomposed.

In addition, the electromagnetic shielding material using a metal face alone does not satisfy various physical and electrical properties, and has some disadvantages when applied as an actual electromagnetic shielding device.

In other words, the electromagnetic wave shielding material made of metal (nickel, copper, nickel-copper) coated fabric, non-woven mesh, etc. shows excellent electromagnetic shielding efficiency, but due to the generation of processed burr and surface oxide film formation. There is a problem of compatibility.

The object of the present invention is to compensate for the above problems, excellent conductivity, oxidation resistance of the surface, tensile strength, having the physical properties such as sheet flexibility, prevention of burr separation of fabric and mesh fabric, and excellent electromagnetic shielding It is to provide a method for producing a multilayer conductive rubber sheet that has properties and high reliability.

The structure of the multilayer conductive rubber sheet with excellent electromagnetic shielding efficiency is made of flake and dendrite type, granule type, amorphous (copper, nickel, silver, copper coated with silver, etc.). A conductive paste layer made of a metal or a metal alloy, carbon black, or graphite; A conductive rubber sheet layer; The conductive material layer made of any one of a conductive fabric, a nonwoven fabric, or a mesh is formed in a multilayered structure in which the conductive material layers are bonded to each other in the up and down direction. To help.

Figure 1a is a cross-sectional view of the sheet of the multilayer structure produced by the present invention,

Figure 1b is a cross-sectional view of the sheet of the multilayer structure produced by the present invention,

2 is a chart comparing electromagnetic shielding efficiency in a far-field region.

(a) is the electromagnetic shielding efficiency of the single-layer silver-coated copper rubber sheet,

(b) is a table showing the sheet electromagnetic shielding efficiency of the multilayer structure produced by the present invention.

* Explanation of symbols for main parts of the drawings

1: conductive paste layer 2: conductive rubber sheet layer

3: conductive fiber material layer 4: adhesive layer

The configuration of the present invention will be described in detail with the accompanying drawings.

1 is a cross-sectional view of a sheet of a multilayer structure manufactured by the present invention, Figure 2 is a diagram comparing the electromagnetic shielding efficiency in the far-field region, (a) is the electromagnetic shielding efficiency in a single-layer silver coated copper rubber sheet , (b) is a chart showing the sheet electromagnetic shielding efficiency of the multilayer structure produced by the present invention.

As shown in Fig. 1, the sheet of the multilayer structure according to the present invention,

Flake and dendrite type, fine particle type

(Granule type), a conductive paste layer (1) containing an amorphous (copper, nickel, silver, silver coated copper, etc.) metal or metal alloy, carbon black, graphite, and a conductive rubber sheet The layer 2 and the conductive material layer 3 made of any one of a conductive fabric, a nonwoven fabric or a mesh are each made of a multi-layered structure joined together in a vertical direction.

Preferably, the conductive paste layer 1 is an upper layer, a conductive rubber sheet layer

(2) In this middle layer, the conductive material layer 3 which consists of any one of a conductive fabric, a nonwoven fabric, or a mesh is comprised in the lower layer,

An adhesive layer 4 made of a double-sided tape or the like is formed on the bottom surface of the conductive material layer 3 to facilitate bonding to the surface of electronic products such as mobile phones and laptop monitors.

The multi-layered sheet according to the present invention configured as described above has excellent conductivity and electromagnetic shielding efficiency, surface oxidation resistance, and tensile strength, and excellent sheet flexibility and prevention of baffle release of fabrics and mesh fabrics. As a use of electromagnetic shielding materials and antistatic materials for mobile communication and electrical and electronic products such as PCs, LCD monitors, PDAs, and the like, they may be used in various forms such as conductive rubber sheets and conductive cushion rubber gaskets.

On the other hand, the metal alloy (copper, nickel, silver, silver coated copper, etc.) used in the conductive paste layer 1 may be a flake or dendrite type, a granule type or an amorphous type. Metals in the form.

60 wt% or less of the metal is added to the resin (Resin) of the urethane, acrylic, polyester system to prepare a paste, and roll coating or casting

It is coated by (Casting), Screen printing or Spray (Spray) method.

As the intermediate layer, the conductive rubber sheet layer 2 may be a flake or dendrite type, a granule type, an amorphous metal (copper, nickel, silver, copper coated with silver, etc.) or a metal alloy. The urethane, acryl, ethylene copolymer is a copolymer of ethylene and a monomer having a carboxyl group or a derivative thereof, and preferably, 80 wt% or less of ethylene ethyl acrylate, ethylene methyl acrylate or ethylene vinyl acetate is added to the turbine impeller. Compound in the type of dissolver, kneader, benbury mixer, boothneader or open roll mill, or mix the mixture first in a Henschel mixer, ribbon blender, V blender, etc. It can be compounded in a twin extruder. The method of laminating the compound into a sheet on the conductive fabric is formed by casting or knife coating by a doctor blade method, and when manufacturing a single layer of conductive rubber sheet, also by using a compounding conductive paste A conductive rubber sheet having flexibility and elongation is produced by casting or knife coating by a blade method, a calendering method, or a T-die extrusion and calendering.

The present invention as described above will be described with reference to Examples.

(Example 1)

The composition of the present invention is a lower layer, the conductive material layer (3) is a copper and nickel-coated polyester in the fabric, non-woven fabric, mesh of polyester coated with metal (copper, nickel, nickel-copper, etc.) [ Thickness: 0.1mm (or 0.05 ~ 2mm)] Conductive fabric is used, and the middle layer is coated with flake or dendrite type, granule type, and amorphous type silver. Manufactured copper powder (or metal such as nickel, copper, silver) to 50wt% (or 15 ~ 85Wt%) of urethane (or acrylic, PVC, polyester, EPDM, silicone, etc.) resin to coat conductive rubber sheet

[Thickness: 0.3 mm (or 0.03 to 5 mm)]. When the lower conductive material layer (3) and the middle conductive rubber sheet layer (2) are individually bonded, they are coated with a conductive adhesive and then pressed by a roll press (or by using double-sided tape or pressing at a high temperature). have)

Conductive by adding 50wt% (or 15 ~ 85Wt%) of silver (or metal such as nickel, copper, silver coated copper, etc.) to urethane (or acrylic, PVC, polyester, EPDM, silicone, etc.) resin as upper layer After preparing a paste [thickness: 0.01mm (or 0.005 ~ 0.05mm)] to the surface of the conductive rubber sheet layer 2, the conductive paste through a roll coating, casting or printing method By forming the layer 1, a sheet having a multilayer structure is produced.

In addition, considering the marketability and applicability, a multilayer electromagnetic shielding rubber sheet having flexibility and stretchability could be manufactured by forming an adhesive layer 4 by double-sided tape or a conductive adhesive on the lower surface of the conductive material layer 3. .

On the other hand, as a result of measuring the electromagnetic wave shielding efficiency of the multilayer electromagnetic shielding conductive rubber sheet manufactured by the present invention, as shown in Figure 2, the multilayer structure sheet according to the present invention than the single-layered silver-coated copper rubber sheet of the same thickness Excellent shielding efficiency was shown over the entire frequency range.

(Example 2)

The composition of the present invention used a conductive material layer (3) made of copper-nickel-coated polyester nonwoven fabric (thickness: 0.1 mm (or 0.05-2 mm)) as a lower layer, and a dendritic crystalline form as a middle layer. A conductive rubber sheet 2 was manufactured by adding 60 wt% (or 15 to 85 Wt%) of silver coated copper powder in the form of dendrite type to urethane (or acrylic, PVC, polyester, EPDM, silicone, etc.) resin. : 0.3 mm (or 0.03-5 mm)]. The lower layer and the middle layer were attached using a roll press in a high temperature state after the adhesive treatment. 50 wt% (or 15 ~ 85Wt%) of carbon black or graphite is added to urethane (or acrylic, PVC, polyester, EPDM, silicone, etc.) resin as the upper layer to make conductive paste [thickness: 0.01mm ( Or 0.005 ~ 0.05mm)] (1), and then roll coating, casting or printing on the surface of the conductive rubber sheet 2 in the middle layer.

Multilayers were formed through printing.

In addition, by forming an adhesive layer 4 by double-sided tape or a conductive adhesive on the lower surface of the conductive material layer 3 in consideration of the commerciality and applicability, it is possible to manufacture a multilayer electromagnetic shielding rubber sheet having flexibility and stretchability. there was.

(Example 3)

The composition of the present invention used a conductive material layer (3) by copper-nickel coated polyester mesh [thickness: 0.08mm (or 0.05-2mm)] as a lower layer, 100 parts by weight of a polar polyolefin resin as a middle layer kneader, banbury mixer or roll first processed into sheet form, mixed with 300 to 1000 parts by weight of silver coated copper powder in the form of dendrite type and inorganic flame retardant 60 to 150 parts by weight of aluminum hydroxide (or magnesium hydroxide) and 0.5 to 5 parts by weight of a flame retardant aid are compounded in a kneader, a Benbury mixer, a bus kneader or an open roll mill, or in a Henschel mixer, ribbon blender or V blender. The mixture was first thoroughly mixed and then compounded in a kneader, a Benbury mixer, a booth kneader, a single extruder, a twin extruder, and the like. The method of laminating the compound into a sheet is to provide a sheet for shielding electromagnetic waves having flexibility and elongation by calendering with four bone rolls after the die die extrusion as well as a calender in order to orient and laminate metal flakes in a direction parallel to the sheet. Preparation [thickness: 0.3 mm (or 0.1-2 mm)] was used. The lower and middle layers were attached using double sided tape. The upper layer is 60wt% (or 15 ~ 85Wt%) of silver coated copper powder to the urethane resin to prepare a conductive paste [thickness: 0.01mm (or 0.005 ~ 0.05mm)], and then the conductive rubber sheet layer of the middle layer (2) The sheet having a multilayer structure was formed on the surface by roll coating, casting, or printing.

In addition, by forming the adhesive layer 4 by the double-sided tape or the conductive adhesive on the lower surface of the conductive rubber sheet layer 2 in consideration of the marketability and applicability, a multilayer electromagnetic shielding rubber sheet having flexibility and stretchability could be manufactured. .

As described above, the multi-layered sheet according to the present invention has excellent physical properties such as conductivity, surface oxidation resistance, and tensile strength, flexibility of the sheet, and prevention of burr detachment of fabrics and mesh fabrics, It will have excellent electromagnetic shielding characteristics and high reliability.

That is, the structure of the multilayer conductive rubber sheet having excellent electromagnetic shielding efficiency is flake and dendrite type, granule type, amorphous (copper, nickel, silver, copper coated with silver, etc.) A conductive paste layer 1 made of a metal or metal alloy, carbon black or graphite; A conductive rubber sheet layer 2; The conductive material layer 3 made of any one of a conductive fabric, a nonwoven fabric, or a mesh is formed in a multi-layered structure in which the conductive material layers 3 are joined in the vertical direction, and the electromagnetic wave shielding properties and high reliability together with the physical properties such as tensile strength and flexibility To satisfy all of them.

The multi-layered sheet according to the present invention can be applied to electromagnetic shielding and antistatic materials in various forms such as conductive rubber sheets and conductive cushion rubber gaskets in mobile communication and electrical and electronic products such as mobile phones, laptops, PCs, LCD monitors, PDAs, and the like. have.

Claims (13)

Flake and dendrite type, fine particle type Granule type, amorphous (copper, nickel, silver, silver coated copper, etc.) metals or metal alloys, carbon black, graphite are among urethane, acrylic, PVC, polyester, EPDM, and silicon Conductive paste layer added 15 ~ 85Wt% to any kind of resin (1), flakes, dendrite and fine particles Granule type, amorphous (copper, nickel, silver, silver coated copper, etc.) metals or metal alloys, carbon black, graphite are among urethane, acrylic, PVC, polyester, EPDM, and silicon Conductive rubber sheet layer added 15 ~ 85Wt% to any kind of resin (2) and the conductive material layer (3) made of polyester, coated with a metal (copper, nickel, nickel-copper, etc.), nonwoven fabric, or mesh form each joined in a vertical direction to form a multilayer structure. Multi-layered sheet with excellent electromagnetic shielding performance. The multi-layered sheet having excellent electromagnetic shielding performance according to claim 1, wherein an adhesive layer (4) is formed on the lower surface of the conductive material layer (3). The multi-layered sheet having excellent electromagnetic shielding performance according to claim 2, wherein the adhesive layer (4) is made of a double-sided tape or a conductive adhesive. The multi-layered sheet having excellent electromagnetic shielding performance according to claim 1, wherein the conductive paste layer (1) has a thickness of 0.005 to 0.05 mm and the conductive rubber sheet layer (2) has a thickness of 0.03 to 5 mm. The multi-layered sheet according to claim 1 or 4, wherein the conductive material layer (3) has a thickness of 0.05 to 2 mm. A conductive material layer 3 composed of a woven fabric, a nonwoven fabric, or a mesh coated with a metal (copper, nickel, nickel-copper, etc.) is prepared, and a flake or dendrite type, particulate type Granule type, amorphous metal or metal alloy, carbon black, graphite added 15 to 85 Wt% to any one of urethane, acrylic, PVC, polyester, EPDM, and silicone resins The conductive rubber sheet 2 is coated or bonded to the upper portion of the conductive material layer 3, flake or dendrite type, granule type, amorphous metal or metal 15 to 85 Wt% of an alloy, carbon black, and graphite to urethane, acrylic, PVC, polyester, EPDM, and silicone resins are added to prepare a conductive paste, and then the conductive rubber sheet. Of layer (2) Roll coating (Roll coating), casting (Casting) or printing (Printing) method a process for producing a multi-layer structure of the electromagnetic wave shielding performance is excellent, characterized in that that forms a conductive paste layer (1) over the sheet surface. The method according to claim 6, wherein the conductive material layer (3) and the conductive rubber sheet layer (2) are bonded by pressing a roll press after applying a conductive adhesive. Manufacturing method. The method of manufacturing a sheet having a multilayer structure with excellent electromagnetic shielding performance according to claim 6, wherein the conductive material layer (3) and the conductive rubber sheet layer (2) are bonded using double-sided tape. 7. The method of claim 6, wherein the metal or metal alloy, carbon black, graphite is selected from the group consisting of urethane, acrylic, PVC, polyester, EPDM, and silicone in order to make the conductive rubber sheet layer (2). The mixture made by adding the resin is compounded in a turbine impeller type dissolver, kneader, benbury mixer, booth kneader or open roll mill, or thoroughly mixed in a Henschel mixer, ribbon blender or v blender first, and then kneader, benbury mixer, After compounding in a booth kneader, a single extruder, or a twin extruder, the compound rubber sheet layer (3) is formed by laminating the compound on the conductive material layer (4) of the multilayer structure with excellent electromagnetic shielding performance Manufacturing method of the sheet. 10. The method according to claim 9, wherein the laminating the conductive rubber sheet layer 3 on the conductive material layer 4 is formed by casting or knife coating by a doctor blade method. The manufacturing method of the sheet | seat of the multilayered structure which was excellent in the electromagnetic shielding performance. 7. The electromagnetic shielding performance of claim 6, wherein the inorganic rubber flame retardant comprises 60 to 150 parts by weight of an inorganic flame retardant made of aluminum hydroxide, magnesium hydroxide, or the like based on 100 parts by weight of the resin when forming the conductive rubber sheet layer 2 Method for producing a sheet having a multilayer structure. 12. The electromagnetic wave shielding performance as claimed in claim 6 or 11, wherein 0.5 to 5 parts by weight of a flame retardant aid is added to 100 parts by weight of the resin when the conductive rubber sheet layer 2 is formed. Method for producing a sheet having a multilayer structure. 7. A method according to claim 6, wherein the adhesive layer (4) is bonded to the lower surface of the conductive material layer (3).