KR100477019B1 - High polymer microcellular foam conductive gaskets and method for preparing thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to gaskets made of high polymer sponge elastomers for electric and electro magnetic shielding and to methods of manufacturing the same. More specifically, uniformly perforate the fabric of the shock and vibration prevention gaskets used in various electronic communication devices, and then dry-crosslinking by uniformly dipping and coating the conductive coating material into the perforated space and the upper and lower sides. Alternatively, after laminating a conductive fabric, a conductive nonwoven fabric, or a conductive metal film treated with a conductive adhesive on the upper and lower surfaces or one surface of the polymer sponge elastic body for gasket, the fabric is uniformly punched and the conductive coating material is formed in the perforated space. Surface permeability and volume resistivity are reduced by constant penetration coating, so that it has both shock and vibration absorbance A conductive electronic communication device gasket and a method of manufacturing the same.

Description

 High polymer microcellular foam conductive gaskets and method for preparing background

The present invention relates to a gasket having electrical conductivity and a method of manufacturing the same that can be used for electromagnetic and electromagnetic wave shielding of various electronic communication devices.

The gasket according to the present invention is manufactured by imparting conductivity to a polymer elastomer, and is simpler to use than a conductive polymer sponge elastomer manufactured by a conventional method, has excellent conductivity, has high mechanical and physical strength, and prevents high impact and vibration. It retains the required hardness and uniform bubble structure while maintaining its low compressive and deformability.

In designing various electronic communication devices, various harmful electromagnetic waves or electromagnetic waves generated on the circuits may disrupt the functions of surrounding electronic communication devices, degrade performance, damage noise and images, shorten the lifespan, and generate defective products. Is the biggest cause. Various electromagnetic and electromagnetic wave shielding materials conventionally used to block this include various metal plates, metal plated fabrics, conductive paints, and conductive tapes. .

Conductive materials made of polymer sponge elastomers include breathable open cell low density polyurethane foams and closed cell polyethylene foams, but have low density, low shock absorption and vibration resistance, and low electrical conductivity. Because of its weakness (volume resistivity: more than 10 ⁴ Ohm · cm), it has been used mainly for the packaging of electronic communication devices.

Conventionally used elastomers for shock and vibration preventing gaskets include high density polyurethane foam. The high-density polyurethane foam is a known polyhydroxy compound (organic polyisocyanate compound), organic polyisocyanate compound (chain extender), catalyst (catalyst), foam stabilizer (silicone foam stabilizer) and the like After mechanically mixing with an inert gas such as in a high speed mixer to obtain a foamable composition (specific gravity 0.1 to 1.0 grs / cu.cm), the foamable composition is coated on a conveyor belt (endless conveyor belt) which is a heat treatment device. It is manufactured by molding and crosslinking to a constant thickness using an apparatus. If desired, fabric or plastic films can be laminated on one or both sides (US Patent No. 3,755,212, US Patent No. 3,862,879, US Patent No. 4,216,177 and US Patent No. 5,859,081).

In order to impart conductivity to such a high density polyurethane foam sheet, the following methods were mainly used.

As a conductive filler in the polyhydroxy compound used in the production of the high-density polyurethane foam, known fine carbon black (graphite) or graphite (silver), copper (copper), nickel (nickel), aluminum ( There is a method of uniformly dispersing fine metal powder such as aluminum). However, in order for these conductive materials to be added to the high-density polyurethane foam compound as a filler to have conductivity, it is necessary to form a pathway in which the particles have continuity between particles in the cross-linked polyurethane foam. That is, the metal particles or carbon black particles should be in close contact with each other in the material so that the conductive particles can pass electrons to each other.

For example, in order to impart electric conductivity by blending carbon black with the urethane foam, 15 to 30% by weight of the amount of polyhydroxy compound used should be added depending on the particle size and conductivity of the carbon black to be used. In order to obtain better conductivity, 40 wt% or more should be added. However, the addition of such a large amount of carbon black makes it difficult to uniformly disperse and inhibit the melt viscoelasticity of the resin, the carbon particles agglomerate with each other and the viscosity rises extremely, making it impossible to transport and foam the raw materials. In addition to increasing the specific gravity of the product and the deterioration of physical properties, the function as a gasket for an electronic communication device having shock and vibration absorption is lost. On the other hand, in the case of using a metal powder, the metal powder must be blended two to three times or more than carbon black to cause conductivity, in which case there is a problem in that the dispersibility becomes poor and the specific gravity becomes heavy. As a result, they are not currently used as conductive fillers in high-performance density polyurethane foams having shock and vibration resistant properties.

Meanwhile, conventional electromagnetic wave and electromagnetic wave shielding materials which require only surface resistivity, which are mainly composed of conductive materials such as metal plates, metal plated fabrics, and conductive tapes. Coating materials have been applied to various fabrics, nonwovens, paper or other plastic films. Since volume conductivity was not imparted, they were mainly used for surface conduction only, and a product having both surface conductivity and volume conductivity based on a polymer sponge elastomer was not developed.

However, a sponge elastomer made of a polymer material such as soft polyurethane foam having a low specific gravity and cushioning has been used for packaging transportation, buildings, window frames and other electromagnetic wave shielding facilities of various electronic components or semiconductor chips. However, they are all made of insulators with high electrical resistance, and in order to be processed and used in various forms according to their use, polyurethane foams (polymer sponges) have been previously cut to a predetermined size or molded into molds. After the entire surface is adhesively processed with a conductive fabric or nonwoven fabric coated with an adhesive, or the conductive fabric or nonwoven fabric is built into a side in a predetermined mold in advance, and then the polyurethane foam mixture is manufactured by a complicated process of injecting and foaming into a specially manufactured molding machine. It became. As a result, the manufacturing cost was high and it could not be used as a gasket for a telecommunication device that absorbs shock and vibration while blocking electromagnetic waves of the telecommunication device (see Fig. 9).

These polymer sponge products, in order to achieve the function as the electromagnetic wave and electromagnetic wave shielding material having the vertical volume conductivity required, the sponge powder directly into the fine powder such as conductive carbon black, graphite, gold, silver, copper, nickel or aluminum directly It had to be prepared by injection into the foam formulation. In this case, as described above, the input amount of the conductive material is limited due to difficulty in the manufacturing process and deterioration of physical properties. As a result, the volume resistivity of the conductive material is 10 ⁴ Ohm · cm or less. Gaskets imparted with volume conductivity as shock and vibration absorbing high density elastomeric foams that are difficult to obtain and require particularly high elasticity, low hardness and very low permanent compression set have not been developed.

The present inventors have been studied to impart electrical conductivity to the conventional high-density elastomer foam composition, while solving various problems of the prior art.

As a result, after perforating the elastic body, the conductive material is filled into the surface and the perforated hole, or the conductive fabric or the conductive metal film is laminated on the upper and lower sides or one side of the elastic body, and then perforated, and then in the perforated space. By infiltration-coated dry crosslinking of the conductive coating material, unlike the above method using carbon black or various metal powders as the conductive fillers, the physical properties are not reduced and the process is simple. The present invention has been completed by manufacturing a gasket for an electronic communication device which can simultaneously obtain desired surface resistivity and volume resistivity.

Accordingly, an object of the present invention is to reduce the physical properties and to simplify the process, and to provide the desired surface resistance and vertical volume resistance at the same time while maintaining the shock absorption and vibration resistance of the high density elastomeric gasket. To provide a gasket.

It is also an object of the present invention to provide a method for producing the gasket.

The present invention provides a gasket for an electronic device manufactured by cutting a conductive sheet obtained by drilling a hole in a polymer elastomer sheet and then coating the sheet surface with a conductive material and filling the perforated hole with the conductive material to a suitable size. .

In addition, the present invention is a conductive fabric such as a conductive non-woven fabric or a conductive metal film such as copper, aluminum, nickel, silver, gold, etc., the upper and lower sides or one side of the sheet The present invention provides a gasket for an electronic device manufactured by cutting a conductive sheet obtained by laminating it in advance using a conductive adhesive and then punching it, and filling the perforated space with a conductive material to an appropriate size.

In the step of filling the perforated space with a conductive material, the conductive material does not have to fill all of the perforated space, preferably, sufficient electrical conductivity is achieved by coating the conductive material on the wall of the perforated space. Can be obtained.

The type of the polymer elastomer sheet may be used without limitation as long as the material is made of an elastic polymer material. For example, polymer synthetic resin such as polyurethane foam sheet, PVC, silicone, ethylene vinyl acetate copolymer, polyethylene sheet or NR, SBR, EPDM, NBR, neoprene Natural rubber, solid rubber sheets or sponge sheets.

The thickness of a sheet can use 0.5 mm-10.0 mm. The thickness of the sheet can be adjusted according to the application.

Although it does not specifically limit as said conductive material for imparting electrical conductivity, For example, carbon black, graphite, gold, silver, copper, nickel, aluminum, etc. can be used. They can be used in the form of fine powders for surface coating and filling in holes.

The thickness (conductive film) of the conductive material coated on the polymer elastomer sheet can be easily adjusted by those skilled in the art as necessary. The thickness of the conductive film may be expressed in mil units, where 1 mil is equal to 0.025 mm. Preferably, the thickness of the conductive film can be adjusted in the range of 0.1 mil to 3.0 mil. More preferably, it is preferably 0.3 mil to 1.0 mil, but depends on the application.

On the other hand, when using a conductive fabric or a metal conductive film laminated on the sheet, the thickness of the conductive fabric or metal conductive film can be adjusted in the range of 1 to 10 mil. More preferably, the range of 2-8 mil is good. More specifically, the thickness of the conductive fabric is best in the range of 3 to 4 mils, and the thickness of the metal conductive film is most appropriate in the range of 2 to 3 mils.

The conductive fabrics include conductive copper, nickel, aluminum, silver to impart conductivity to the surface of a flexible plain or nonwoven fabric made of polyester or nylon. , Gold or copper / nickel, copper / silver, etc. may be used, or may be prepared by depositing or electroless plating. As the metal conductive film, gold, silver, copper, nickel, aluminum, graphite film can be used. As the method of depositing the conductive metal on the fabric, a chemical vapor deposition method which is generally used may be used. Electroless plating of the conductive metal on the fabric may also be performed according to conventional methods. On the other hand, a conductive fabric can also be produced by weaving a fiber coated with a conductive material on the fiber itself.

Commercially available as such conductive fabrics include SR-W23B (PET / Ni + Cu + Ni; ripstop; manufactured by E-Song Corporation), ST-W29B (PET / Ni + Cu + Ni; Taffeta; manufactured by E-Song Corporation) Or SN-W05B (PET / Ni + Cu + Ni; Non-woven; manufactured by E-Song Corporation), etc., SM-W13B (PET / Ni + Cu + Ni; manufactured by E-Song Corporation), SP-W22B ( PET / Ni + Cu; manufactured by E-Song Corporation), SR-W23D (PET / Ni; manufactured by E-Song Corporation) or ST-W25E (PET / Cu; manufactured by E-Song Corporation).

T200 (Fabric / ripstop backing; manufactured by E-Song Corporation), T214 (Fabric / taffeta backing; manufactured by E-Song Corporation) or T254 (backing with Non-woven; manufactured by E-Song Corporation) in the form of a conductive adhesive tape In the form of a metal foil adhesive tape, T267, T288, T286 or T291 (manufactured by E-Song Corporation) may be used.

A commercially available conductive adhesive may be used as an adhesive for bonding the conductive treated conductive fabric or metal film to the polymer elastomer sheet. Those skilled in the art can select an adhesive suitable for the intended use from among commercially available adhesives.

The size of the sheet and the size and spacing of the perforations depends on the use of the gasket. For example, relatively large and thick sheets are used for large electronic devices such as notebook computers, while larger and larger holes are used, while sheets used for relatively small electronic devices such as mobile phones and cellular phones are relatively thin and perforated. The size of is small and the gap between holes is small.

The size of the hole is preferably in the range of 0.1 to 3.0 mm. The number of holes can be about 1-100 per cm 2. The arrangement of the holes is not particularly limited, but the arrangement of the holes can be made constant in terms of convenience of work and electrical conduction efficiency. For example, after drilling holes in a row, when drilling the next row, the angle with the nearest hole arranged in the adjacent row can be adjusted in the range of 30 ° to 90 °. The size, number and arrangement of holes can also be adjusted according to the use of the gasket as described above.

Limiting the diameter of the hole to 0.1 mm to 3.0 mm is a method of penetrating the conductive material, and the conductive material (e.g., conductive carbon black, gray white, gold, silver, copper, nickel, aluminum fine powder, etc.) is mainly used. It is dispersed in a water-soluble or solvent-based blend of an acrylic resin, an epoxy resin or a urethane resin, in which case the viscosity of the conductive material is increased, so that the conductive material having a high viscosity is easily applied and penetrated into the perforated foam sheet under normal pressure. . Of course, the diameter of the hole can be adjusted according to the viscosity and permeability of the conductive material.

On the other hand, in a small electronic device, when the diameter of the perforated hole increases by 1.0 mm or more or the distance between the perforated space and the space increases by 2.0 mm or more, the area occupied by the perforated space for use as a gasket of the small electronic device becomes large. The ratio of the elastic sheet is too high (25% or more), resulting in a decrease in the strength of the product during the die cutting for use of the elastic sheet as a gasket, and also a ratio of shock and vibration absorbency, which decreases its function.

On the other hand, when used as a shock and vibration absorbing polymer elastomer gasket used for medium and large sized electronic communication devices, the perforated space diameter is 1.0 mm or more depending on the purpose and size within the range in which the perforated space is maintained within 25% of the elastic sheet area. By increasing to 3.0mm and increasing the distance between perforations and perforations from 2.0mm to 5.0mm as needed, it is easy to penetrate the perforations and conductive coatings, reduce the perforation cost and increase the upper and lower conductivity of the elastic sheet. .

In particular, when used as a fine gasket of an ultra small electronic communication device, when the 0.3 mm hole diameter causes a problem in the gasket strength and performance in die cutting with the gasket, the diameter of the hole is 0.3 mm or less. It can be perforated by reducing it to 0.1mm, and reducing the distance between perforated spaces to 0.3mm or less. At this time, the viscosity is lowered with water or a solvent within a degree that does not interfere with the conductivity, and repeatedly penetrates into the perforated space through the pressurized vacuum absorption process according to the process of FIG. The conductive coating can be easily applied and penetrated to a desired thickness.

Elastomeric sheets produced in a continuous sheet state are continuously cut into the required size and shape in an angle of 45 ° (FIG. 1C) or 60 ° (FIG. 1B) in order to maintain a constant proportion of the area of the perforated space. It is preferable to arrange the perforated holes by the furnace.

The method of coating and filling the conductive material on the perforated sheet may be any method that does not damage the sheet material. Preferably, the method of coating and filling is preferably a conveyor belt roller.

For example, after forming perforated holes of constant size, spacing and angle in a high-density foam sheet for casting gaskets on a conveyor, carbon black, graphite, gold, silver with conductivity suitable for the application Electrically conductive paints, such as conductive fine metallic powders such as copper, nickel, and aluminum, are applied and penetrated to a predetermined thickness as necessary in the manner shown in the drawings (see FIGS. 3 and 4). The same applies to the case where a conductive fabric or a metal conductive film is laminated.

The gasket according to the present invention provides a highly conductive coating treatment to the gasket fabric for preventing shock and vibration used in various electronic communication devices, thereby providing multifunctionality within a limited narrow space of highly miniaturized electronic communication devices, and providing precise electronics. In addition to physical protection of the device due to shock or vibration of the communication device, it is possible to maximize the function and performance of the electronic communication device by simultaneously blocking various internal and external electromagnetic waves and electromagnetic waves.

The manufacturing method of a polymeric elastomer sheet is not specifically limited. The sheet may be manufactured by a method of manufacturing a foamable polymer resin in a conventional foam form. The method of drilling is also not particularly limited. Those skilled in the art can prepare the sheet according to the necessary needs and then use it by punching it.

Hereinafter, the present invention will be described in detail.

In the fabric manufacturing method for the sheet, the material can be produced using a variety of known polymer sponge elastomer, but in the present invention, in particular by continuous foaming in a high-speed mixer mechanically using air or nitrogen inert gas (endless conveyor) More preferred is a highly frothed high density polyurethane foam which is molded crosslinked on a belt and made into a continuous sheet. The polymeric sponge elastomer sheet used herein is composed mainly of polyhydroxy compound, organic poliyisocyanate compound, crosslinking agent, chain extender, catalyst, and silicone foam stabilizer. A high density urethane foam sheet produced by mechanically mixing an inert gas such as air or nitrogen in a high speed mixer to which the raw material is supplied is molded and crosslinked onto a sheet on a conveyor belt. Other polymer resins can also be prepared by methods similar to the above.

[Production method of gasket]

Method 1

Perforated holes are uniformly formed in the elastic sheet manufactured by a known method, and uniformly dipping and coating a conductive coating material on the uniformly perforated holes and upper and lower surfaces, and then dried and crosslinked to apply the applied conductivity. According to the conductivity of the coating material, a conductive elastomer sheet for an electronic communication device gasket having both shock and vibration absorbing properties that freely give desired surface conductivity and volume conductivity is prepared.

Method 2

Deposition of conductive fabrics produced by known methods, for example copper, nickel, aluminum, silver, gold or copper / nickel mixtures, copper / silver mixtures, etc. Alternatively, a nonwoven fabric prepared by electroless plating, or a conductive fabric prepared by weaving a fiber (thread) coated with a conductive fabric, or a conductive film such as copper, aluminum, nickel, silver, and gold is laminated on the upper and lower surfaces of the elastic sheet. Perforate the holes uniformly, and uniformly dipping and coating the conductive coating material on the regularly perforated holes and the upper and lower surfaces thereof, and then drying and crosslinking them to conduct conductivity of the conductive fabric or film laminated on the sheet and below. Depending on the conductivity of the conductive material, it is possible to freely impart desired surface conductivity and volume conductivity.

Method 3

It is the same as the said method 2 except the conductive fabric manufactured by a well-known method, or the conductive film, such as copper, aluminum, nickel, silver, and gold, laminated on one surface of an elastic sheet. Even in this case, the desired surface and volume conductivity can be freely obtained depending on the conductivity of the conductive fabric or film laminated on one surface of the sheet and the conductivity of the used conductive material.

In the case of a conductive elastic body prepared by blending a conventional conductive filler directly into the foaming composition of the elastic body, physical properties are lowered, and the selection and input amount of the conductive filler are limited, thereby resulting in a volume resistance of 10 ⁴ Ohm · cm Although it was impossible to achieve the following, the conductive elastomer sheet according to the present invention has a surface resistance value depending on the selection of the conductive material or conductive laminate (fabric or film) to be used. Volume resistivity can be adjusted. For example, when the conductive material using carbon black or graphite is used as the coating material, the volume resistivity is 10 ³ Ohmcm, and the conductive material using silver or nickel powder is 10 ^-5 Ohmcm It can be easily obtained to satisfy the electromagnetic shielding function required for electronic communication equipment.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Example 1>

1 is a view showing the formation of perforated holes with a diameter of 0.5 mm in a high-density polyurethane foam sheet (hereinafter referred to as "foam sheet") as a polymer elastomer sheet according to the present invention. The punch and dies of 0.5 mm diameter are arranged at the 60 ° angle shown in FIG. 1B using a punching press, which is generally used for the drilling of sheet metal, and the pitch between the centers of the perforations Was continuously drilled by a perforated frame assembled to be drilled up and down accurately by a hammer (striker) installed by constantly arranging the 1.5mm.

The perforated foam sheet thus forms a plane as shown in FIG.

The thickness of the foam sheet was used was 1.0mm.

The gasket fabric may be used by die cutting in various shapes according to the shock and vibration absorbency of the end-use electronic communication device or the need for EMI / RFI shielding. At this time, in order to always obtain a uniform volume resistivity (volume resistivity) was perforated so that the holes are arranged at 60 ° (angle of Figure 1b) as shown in FIG.

2 is a cross-sectional view of the perforated sheet.

Surface registivity and upper and lower volume resistivity required according to the type of conductive material (coating material) penetrated into the perforated space, the thickness of the coating film, and the density of the perforation according to the diameter of the perforated space and the distance of the perforated space. registivity can be adjusted freely.

FIG. 3 is a view illustrating a process of continuously applying, penetrating and drying crosslinking a known conductive coating to a perforated foam sheet. In the feeder 100 wound around the perforated foam sheet prepared above, Black Conductron 103 ^TM based on conductive carbon black of Kemco International Associates., Inc. (West Lake, Ohio) was used as a coating material as a conductive material. . As shown in FIG. 3, the pressure between the two rolls was increased so that a predetermined amount was applied and penetrated in the upper and lower roll-type coating penetration devices 102 installed in the container 103. The cross-linked tunnel tunnel 106 with a blower heated at 100 ° C. to 150 ° C. was applied after constant application by pressing it again in the compression rollers 104 and 105, which are adjusted to be 0.5 mm, which is 1/2 of It was made to be wound around the final winding device 107.

In this way, the first coated foam sheet is reversed again and then transferred to the initial foam sheet supply device 100 to infiltrate and apply the conductive coating material on the back of the first coated sheet in the same manner, so that the conductive sheet has a uniform thickness on both sides. Not only the coating material was applied, but also the conductive coating material penetrated evenly and completely into the perforated narrow space to form a conductive film. As a result, precision electronic communication device gaskets are provided with uniform surface and volume resistance simultaneously while maintaining a high level of physical properties without any change in the properties of foam sheets manufactured in a special formulation to impart shock and vibration absorption. A high density polyurethane foam sheet for production was obtained.

The film thickness after drying of the conductive material was 0.3 mil (1 mil is 0.025 mm) or more, wherein the volume resistivity and surface resistance of the foam sheet for the gasket were 10 ³ Ohm. On the other hand, for reference, after the conductive material was coated to have a film thickness of 2 mils after drying, the volume resistance of the foam sheet for gasket was lowered to 35 Ohm · cm surface resistance to 40 Ohm · square.

The resistance was measured with a VOAC86A Multimeter from Iwatsu Electric Co., Ltd, Japan.

FIG. 5 is a view of a shock- and vibration-absorbing high density polyurethane gasket imparting conductivity for an electronic communication device that is die-cut into a predetermined shape according to the application after application, penetration, dry crosslinking, and the conductive material after perforation. As a side view of the upper and lower surfaces 301 and 302 of the conductive gasket and the perforated surface 303 in which the conductive coating is applied and penetrated, the gasket thus manufactured has a very low permanent compression set and a high altitude. It has a shock and vibration absorbency of and can simultaneously maintain high surface conductivity and vertical volume conductivity. The gasket manufactured in this way prevents the shock and vibration of cellular phones, personal digital assistants (PDAs), and notebook computers, which require precision and high performance. It can be used as a gasket for electronic and communication devices using LCD protection gaskets and various LCDs that are absolutely necessary, and can further enhance the performance and function of such electronic communication devices.

<Example 2>

Shock and vibration absorbing high density polyurethane foam sheet has a thickness of 0.5mm, and on the upper and lower surfaces of the sheet, a conductive fabric having a conductivity of 0.06 Ohm · square is laminated, and the perforation diameter is 0.3mm, the perforation pitch is 1.5mm, The angle was perforated to 60 °.

In this embodiment, as the conductive fabric, ST-W29B (PET / Ni + Cu + Ni; manufactured by E-Song Corporation), which is a conductive polyester fabric manufactured using a mixed deposition of copper / nickel / copper, was used. It was laminated to the polyurethane foam sheet. The conductive fabric had a thickness of 3 mils and a weight of about 80 g / m ² .

The perforated fabric was applied and filled according to the method of FIG. 4 using Series 599-Y1325, which is based on Nonoxidative Copper of Spraylat Corporation, Mt, Vernon, NY, USA as the conductive coating.

At this time, the surface resistance of the foam sheet for gasket was 0.06 Ohm · square and the volume resistance was 0.05 Ohm · cm.

FIG. 4 shows a method of forming a foam sheet for use in a small gas of the microelectronic communication device described above. When the perforation diameter is narrowed to 0.1 mm to 0.3 mm, the conductive coating material is difficult to uniformly penetrate into a narrow space by the method of FIG. 3 according to the first embodiment, and thus is wound continuously as shown in FIG. 4. The perforated foam sheet 200 is applied onto the sheet by a knife coater 202 at a constant thickness on the coating roller 201 to which the conductive coating material CP is supplied, and then on a plane to proceed. The air is blown between 100 ° C. and 150 ° C. using the same pressure as in the case of FIG. The device is wound on the final sheet winding device 208 through the installed dry crosslinking tunnel 207.

The subsequent procedure followed Example 1.

<Example 3>

In the same manner as in Example 1, but the angle between the holes on the sheet was 45 ° (Fig. 1c).

The film thickness of the conductive material was 1.0 mil. Both the volume resistance and the surface resistance of the foam sheet for gasket were 10 ² Ohm or less.

<Example 4>

The same process as in Example 2, except that the conductive fabric is laminated on only one surface of the high density polyurethane foam sheet.

The film thickness of the conductive material was 1 mil. The volume resistivity of the foam sheet for gasket was 0.04 Ohm · cm and the surface resistance was 0.05 Ohm · square.

Example 5

The same process as in Example 2, except that Series 599-B3730M using silver coated copper of Spraylot Corporation as a coating material.

The film thickness permeated into the perforated holes of the conductive material was 1.0 mil, and the volume resistivity of the foam sheet for the gasket was 0.03 Ohm · cm Surface resistance was 0.04 Ohm * square or less.

The production of shock- and vibration-absorbing conductive high density polyurethane foam sheet according to the present invention is a simple facility, which can easily produce a gasket fabric for electronic communication devices with various functions in a simple process and is superior to conventional methods in terms of production cost. Can be economically produced.

1A is a surface view of a perforated shock and vibration absorbing high density polyurethane foam sheet according to one embodiment of the present invention.

Fig. 1B shows a perforation in the case where the angle between the holes is 60 ° on the sheet.

Fig. 1C shows a perforation in the case where the angle between the holes is 45 ° on the sheet.

FIG. 2 is a side view of the perforated shock and vibration absorbing high density polyurethane foam sheet shown in FIG.

3 is a process chart for applying, penetrating, drying, and crosslinking a conductive coating on a perforated impact and vibration absorbing high density polyurethane foam sheet.

4 is a process chart for applying, infiltrating, drying and crosslinking a pressure-sensitive vacuum absorbing conductive coating to a shock and vibration absorbing high density polyurethane sheet finely perforated to a diameter of 0.3 mm or less.

5 is a shock and vibration absorbent high density polyurethane foam sheet to which the conductive coating is applied, penetrated, dried and crosslinked after perforation.

FIG. 6 shows gaskets for electronic communication devices prepared by die cutting impact and vibration absorbing high density polyurethane sheets coated with, coated, penetrated, dried and crosslinked after perforation.

Figure 7a is produced by laminating a polyester fabric prepared by using a copper-nickel mixed deposition of fibers on both sides of a high-density polyurethane sheet, then applying, penetrating, drying and crosslinking the conductive coating material and die cutting (die cutting) Gaskets for electronic communication devices. (Example 2)

FIG. 7B is a cross-sectional view of the gasket shown in FIG. 7A.

Figure 8a is a laminated fabric of polyester fabric using a copper / nickel mixed fiber deposited on one surface of a high-density polyurethane sheet, and then coated, penetrated, dried and crosslinked by a conductive coating and die cutting Gaskets for electronic communication devices manufactured are shown. (Example 4)

FIG. 8B is a cross-sectional view of the gasket shown in FIG. 8A.

FIG. 9 is a conventional electromagnetic wave shielding material in which a conductive fabric is bonded to a flexible polyurethane foam to give conductivity to the entire surface.

Claims (7)

As a method of manufacturing a gasket for an electronic device having electrical conductivity and shock absorption, Stacking a conductive fabric or a conductive metal film on one or both sides of a sheet having a thickness of 0.5 mm to 10 mm manufactured using a polymer elastomer; Drilling holes having a diameter of 0.1 to 3.0 mm in the stacked sheets at a ratio of 1 to 100 per cm ² ; Applying a conductive material to the perforated holes of the sheet to form a conductive film; And Cutting the sheet on which the conductive film is formed; Method of manufacturing a gasket for an electronic device comprising a. The method of claim 1, wherein the polymer elastomer sheet is polyurethane foam, polyvinyl chloride (PVC), silicon (Silicone), ethylene vinyl acetate copolymer (Ethylene vinylacetate copolymer), polyethylene (Polyethylene), natural rubber (NR), styrene Butadiene rubber (SBR), ethylene propylene rubber (EPDM), nitrile butadiene rubber (NBR), neoprene sheet or sponge sheet Method for manufacturing a gasket for an electronic device. The method of claim 1, wherein the angle between the holes is 45 ° or 60 °. The method of claim 1, wherein the conductive fabric is copper, nickel, aluminum, silver, gold, copper to impart conductivity to the surface of polyester, nylon or nonwoven. A method of manufacturing a gasket for an electronic device, characterized in that it is prepared by depositing or electroless plating a nickel mixture or a copper / silver mixture. The method of manufacturing a gasket for an electronic device according to claim 1, wherein the conductive material is conductive carbon black, gray white, gold, silver, copper, nickel or aluminum fine powder. The method of claim 1, wherein the conductive fabric is a woven fabric using a fiber coated with a conductive material on the fiber itself. A gasket for an electronic device manufactured by the method according to any one of claims 1 to 6.