KR100831649B1 - Method of manufacturing a cushion sheet having an electromagnetic wave shielding property - Google Patents

Abstract

A method of manufacturing a cushion sheet having an electromagnetic wave shielding property is provided to prevent foreign material from being infiltrated into an internal circuit. A method of manufacturing a cushion sheet having an electromagnetic wave shielding property includes the steps of: applying electric conductivity by forming a metallic layer on a surface of the cushion sheet(S101); forming a cut part on the cushion sheet(S102); applying and charging a conductive resin layer on a cut end surface of the cut part(S103); removing a conductive resin remaining on the surface of the cushion sheet and curing the conductive resin on the cut part(S104); and forming a surface conduction layer on one overall surface of the cushion sheet, and forming a conductive tape layer on the other overall surface of the cushion sheet(S106).

Description

Method of manufacturing a cushion sheet having electromagnetic shielding properties {Method of manufacturing a cushion sheet having an electromagnetic wave shielding property}

1 is a process flow chart for forming a metal layer by the electroless plating method on the surface of the electromagnetic shielding cushion sheet according to the present invention

Figure 2 is a process flow chart for forming a metal layer by the vacuum deposition method on the surface of the electromagnetic shielding cushion sheet according to the present invention

3 is a process flow chart showing in detail the electroless plating step of plating on the cushion sheet shown in FIG.

Figure 4 is an enlarged cross-sectional view of the electromagnetic shielding cushion sheet according to the present invention

Figure 5 is a detailed view of the process and the device for curing by applying a conductive resin on the cushion sheet formed with a cut cut portion of the electromagnetic shielding cushion sheet according to the present invention

Figure 6 is a detailed view of the cushion seat is formed with a sheath cutout according to the present invention

Explanation of symbols on the main parts of the drawings

10 cushion seat 11: sheath incision

11a: cutting section 12: vertical plate

13: resin container 14: conductive resin

20: metal layer

30: conductive resin layer

40: surface conducting layer

50: conductive tape layer

The present invention relates to a cushion sheet for blocking electromagnetic waves generated from LCDs such as various electric and electronic devices and protecting the LCDs, and more particularly, Utility Model Registration No. 336060 and Patents issued by the present applicant. From 528132 is to improve the conventional cushion seat manufacturing problems to produce a more reasonable and economical cushion seat.

In general, a wireless mobile communication terminal uses a cushion sheet for LCD which can absorb external shocks and prevent leakage or invasion of static electricity or electromagnetic waves in order to protect the internal LCD. Patent Application No. 8695 discloses a "gasket made of an electrically conductive polymer elastomer and a method of manufacturing the same".

Such a gasket perforated the foam sheet and impregnated the conductive material in the hole of the foam sheet so that the upper and lower surfaces of the foam sheet were energized. However, when the conductive material was filled in the hole, the elastic recovery force of the foam sheet was reduced. If the coating is coated on the inner circumferential surface of the hole, the elastic recovery force of the foam sheet is maintained, but dust may flow into the hole.

Accordingly, the applicant of the present invention, as in Utility Model Registration No. 336060, a sheath cutout portion is formed in the cushion sheet, and the cutout portion of the cushion sheet is bonded to the base surface of the cushion sheet by impregnating and curing the conductive material in the sheath cutout portion. It has been proposed a cushioning material for an LCD having the characteristic of energizing the upper and lower surfaces of the cushion sheet without impairing the elastic recovery power of the cushion sheet.

In addition, the applicant of the present invention has proposed a manufacturing method for manufacturing the cushioning material of the utility model registration No. 336060 described above by the registered patent No. 528132, the manufacturing method of the cushioning material is a roll-type rotary cutter or a die equipped with a blade Shaping the sheath cutout in the cushion sheet using;

Passing the cushion sheet through a resin container filled with a liquid conductive resin to coat the upper and lower surfaces, and simultaneously passing the cushion sheet to the lower portion of the guide vertical plate disposed in the resin container, thereby passing the conductive resin into the sheath cutout. Penetrating and applying a conductive resin to the cut surfaces of the sheath cutout;

Adjusting the thickness of the conductive resin applied to the cushion sheet by passing the cushion sheet coated with the conductive resin through an upper surface coating thickness adjusting device and a lower surface coating thickness adjusting device;

Passing the drying furnace to cure the conductive resin applied to the cushion sheet;

It has been devised a method of manufacturing an electromagnetic shielding cushioning material comprising the step of laminating a conductive mesh tape or a conductive double-sided tape to a cushioning sheet coated with a conductive resin.

In addition, Korean Patent No. 619573 discloses nickel, copper, gold, silver, tin, cobalt, etc., by electroless plating, electrolytic plating, or substitution plating by ultrasonic cleaning on a cushion sheet in which fine holes are closely arranged at regular intervals. A method of producing a conductive polymer cushion sheet having excellent lamination absorption, electromagnetic wave and elastic recovery ability has been proposed by plating the surface of the cushion sheet and the surface of the hole (not to block the hole).

However, although a method of plating a metal with electroless plating on the cushioning material according to the above-mentioned patent registration No. 0619573 (registered on August 28, 2006) has been introduced, the cushioning material falls off the metal when the bending and bending are repeated. The phenomenon (the phenomenon in which the metal plating layer is broken or torn off to separate the fine powder) has a disadvantage of causing a problem due to an electrical short circuit when applied to an electronic circuit.

In addition, the manufacturing method for the "manufacturing method of electromagnetic wave shielding cushioning material" introduced in the applicant's patent registration No. 0528132 (registered on November 4, 2005) is economical by using a large amount of precious metals such as silver and nickel, and surface contamination and oxidation Has the disadvantage of easy.

The present invention has been made to improve the problems described above, the step of providing an electrical conductivity by forming a metal layer on the surface of the cushion sheet; Molding a sheath incision on the cushion sheet; Applying and filling a conductive resin to the cut end surface of the sheath cutout; Removing the conductive resin on the cushion sheet surface and curing the conductive resin on the sheath cutout; Forming a surface conductive layer on one front surface of the cushion sheet; Forming a conductive adhesive layer on the other front side of the cushion sheet,

While preventing the contamination of metal particles such as excessive bending and tensioning, they exhibit excellent electromagnetic shielding characteristics at relatively low cost, and electromagnetic shielding cushion sheets having electrical resistance of 1.0 Ω / cm or less in the vertical and horizontal directions It is an object of the present invention to provide a method for manufacturing a cushion sheet having an electromagnetic shielding characteristic of a feature that can compensate for the disadvantages of the cushion sheet and the shield member.

Referring to the embodiment of the present invention for achieving the above object as follows.

 First, referring to FIGS. 1 and 2 and 3, the method for manufacturing the electromagnetic wave shielding cushion sheet according to the present invention is performed by electroless plating the cushion sheet 10 (S101) or by vacuum deposition (S201). On the surface of 10) to form a metal layer 20 having electrical conductivity,

The cushion sheet 10 is formed by using a roll-type rotary cutter or a blade equipped with a die (so-called “auto die cutting machine) to form a cut cut portion 11 on the cushion sheet (S102),

As shown in FIG. 5, the cushion sheet 10 passes through the resin container 13 filled with the liquid conductive resin 14 and passes through the lower portion of the guide vertical plate 12 disposed in the resin container 13. By penetrating the conductive resin into the sheath cutout 11 shown in FIG. 6 by applying a conductive resin to the cut end portions 11a of the sheath cutout 11 to cure,

The carbon black is coated on one side of the cushion sheet to which the conductive resin is applied to the cut end 11a of the sheath cutout (S105), or one side of the cut sheet is coated with a conductive adhesive or aluminum foil (S105) vertically and horizontally. Manufactured to enable energization in the direction.

In this case, the cushion sheet 10 may be made of foamed rubber, foamed polyurethane, foamed neoprene, foamed polyolefin, and the like, with a thickness ranging from 0.2 to various uses. It can be variously adjusted to 5mm.

If the manufacturing method described in more detail by the step by step, as shown in Figure 1 electroless plating the cushion sheet 10 in the electroless plating step (S101). The electroless plating step is largely divided into two steps as shown in FIG. 3, which is a pretreatment step S300 and a plating step S400.

That is, before the sheath cutout 11 is formed in the cushion sheet 10, the cushion sheet is ultrasonically cleaned (S301), an etching process (S302) and a catalytic process (S304), water washing (S305) and tin removal process (S306). The pretreatment step (S300) and the electroless nickel plating (S401) and electroless copper chloride plating (S402), electroless copper sulfate plating (S403), electrolytic nickel plating (S404), electroless nickel plating (S405) of the By performing the plating step (S400) having a process in sequence to form a metal layer 20 of the conductive plating surface to make electricity flow in the horizontal direction of the cushion sheet.

In the electroless plating method described above, the conductive resin containing silver powder is used in a minimum amount only on the cut surface 11a of the sheath cutout portion 11, and the entire surface of the cushion sheet 10 is subjected to electroless plating, thereby making it expensive. The cost savings can be minimized by greatly reducing the amount of raw materials used.

      In addition, as shown in FIG. 2, in the vacuum deposition step S201, the cushion sheet 10 is vacuum deposited.

Vacuum deposition is a PVD (Physical Vaporation Deposition) method, which controls the chamber to a vacuum of 10 ^-3 torr or less at atmospheric pressure, and cushions atoms and molecules of metals to ionize and deposit argon gas (Ar gas). By adsorbing on the surface of the sheet, the metal layer 20 of the conductive coating surface is formed to make electricity flow to the surface of the cushion sheet.

At this time, the electroless plating method and the vacuum deposition method performed on the cushion sheet may be performed by double-sided plating or vacuum deposition and cross-sectional plating after one side of the cushion sheet is plated. Silicon may be plated after curing by curing a thin coating in the cushion sheet to a thickness of 5μm or less within the thickness range does not affect the vertical resistance of the cushion sheet.

In addition, the electroless plating step (S101) and vacuum deposition (S201) step may be performed by changing the conductive resin coating step (S103) and the curing step (S104) and the process order to be carried out in the sheath cutout.

In addition, the conductive resin layer 30 is conductive such as copper (Cu), nickel (Ni), aluminum (Al), copper, and coating silver (Cu + Ag) in 10 to 20% by weight of synthetic resins such as urethane and acryl. 80 to 90% by weight of the metal powder is mixed, and the mixture contains an additive, a curing agent (2.5 to 5% by weight based on the total weight), a sedimentation inhibitor (2.5 to 5% by weight based on the total weight), and a thickener (2 to 5% by weight based on the total weight). %) Is further mixed and compounded,

The synthetic resin compounding ratio of the conductive synthetic resin composition is not mixed with 3 to 5% by weight or more based on the total composition, and the conductive synthetic resin composition before processing can be maintained in a liquid state.

If the blending ratio of the synthetic resin composition is increased by about 50% or more with respect to the whole composition, the conductive synthetic resin composition is released from the liquid state and becomes a sticky gel state or dough state, making it difficult to uniformly coat the cushion sheet surface, and thus to uniform the electrical conductivity. Will not be able to maintain stable.

On the contrary, if the mixing ratio of the conductive metal powder is reduced by a certain ratio with respect to the whole composition, the electrical conductivity rapidly decreases after coating on the cutout section 11a of the cushion sheet, which may reduce the static electricity removal efficiency and harmful electromagnetic wave blocking efficiency, which is accumulated in the device. will be.

Therefore, the conductive sheet is sheathed by passing the cushion sheet 10 through the resin container 13 filled with the liquid conductive resin 14 to the lower portion of the guide vertical plate 12 disposed in the resin container 13. The conductive resin layer 20 in which the conductive resin is applied and cured is formed on the cut end face 11a of the sheath cutout part 11 by penetrating the cutout part 11.

In such a state, the surface conductive layer 40 made of carbon black or conductive fabric or aluminum foil is formed on the entire surface of one side of the cushion sheet 10, and the carbon black or conductive fabric or aluminum foil as described above is used. The reason is that one side of the cushion sheet 10 is an adhesive surface bonded to an LCD or the like, while the other side is an exposed surface rather than an adhesive surface, so that the exposed surface is subjected to electrical conductivity.

That is, in the case of laminating or coating the carbon black, the conductive fabric, the aluminum foil, etc. using a separate conductive adhesive, the required cost is reduced to 1/2 compared to the method of coating the conductive resin by the conventional method, of course, In the case of the conventional conductive resin, since the metal powder is loaded, there is a problem that the uniformity of the appearance and the electrical conductivity characteristics are deteriorated due to the oxidation phenomenon when the base is touched with the hand, but the carbon black, the conductive fabric, and the aluminum foil When used, it is possible to overcome the above-mentioned conventional problems.

In this case, the carbon black coating solution is mixed with 10 to 20% by weight of carbon black powder, 10 to 20% by weight of liquid polyurethane resin, and 60 to 80% by weight of methyl ethyl ketone (MEK) to have a viscosity of 2000 to 5000 cps. It is prepared in a liquid state in a (slurry) state.

Therefore, the cushion sheet is cut through the comma coater and the doctor blade device to form a conductive resin layer 30 having a thickness of 10 to 50 μm through a comma coater and a doctor blade device on the cut end face 11a of the cushion sheet. The conductive resin applied and cured on the end face 11a and the surface conductive layer 40 made of the carbon black are bonded to each other so that electricity is energized in the vertical direction of the end face of the cushion sheet 10.

The comma coater and doctor blade device described above are provided with a drying furnace so that coating and drying can be performed simultaneously.

The surface conductive layer 40 by the carbon black is carried out to prevent oxidation of the metal layer 20 on the cushion sheet surface and to prevent the metal layer 20 from being broken when the cushion sheet is folded.

At this time, the surface conductive layer made of carbon black may omit the carbon black coating process (S105) when the thickness of the cushion sheet 10 is 1 mm or less, because the thickness of the cushion sheet becomes thick and the metal is electroless. The reason is that even if the plated or vacuum-deposited cushion sheet is bent intensely, the shear stress and tensile stress received by the metal layer 20 formed on the cushion sheet are weak and the metal layer 20 is not destroyed. On the other hand, if the thickness of the cushion sheet 10 is less than 1 mm, since the shear stress of the metal layer 20 formed when the cushion sheet is folded, the metal layer 20 may be torn or broken.

In particular, in addition to the carbon black described above, the conductive fabric or the aluminum foil is combined with the entire surface of one side of the cushion sheet to impart surface electrical conductivity, and its characteristics are very excellent at 0.1 ohm or less.

When the surface conductive layer 40 is formed on the entire surface of one side of the cushion sheet 10 as described above, the conductive tape layer 50 made of conductive mesh tape or inorganic conductive double-sided tape is formed on the other side of the cushion sheet 10. )

The conductive mesh double sided tape is made of a double sided tape by applying an acrylic adhesive to a thin metal mesh, and the base material is a metal mesh.

In this case, since the nickel powder of the fine particles are used in the adhesive, the metal mesh and the nickel powder are double-sided tapes serving as conductors, and the surface resistance thereof is measured about 0.1 ohm.

In addition, the inorganic conductive double-coated tape is prepared by mixing the conductive powder (for example, nickel, copper, silver) in the adhesive without a mesh used as a substrate, and the surface resistance is measured about 0.1 ohm.

Such a cushion sheet of the present invention has a metal layer 20 formed on one surface or both surfaces of the cushion sheet 10, as shown in Figure 4, the surface conductive layer 40 on one side of the entire surface of the cushion sheet 10 The conductive tape layer 50 is formed on the other side of the entire surface.

In addition, the conductive resin layer 30 is formed in the cut end surface 11a of the sheath cutout part 11 of the cushion sheet 10 mentioned above.

      Hereinafter, preferred embodiments of the present invention will be described.

Example 1

The foamed polyurethane cushion sheet was subjected to ultrasonic cleaning in a 5 to 15% caustic soda chemical bath at 60 to 80 ° C to give hydrophilicity, and 10-10% caustic soda solution in an etching bath at a temperature of 75 to 100 ° C. After washing with water, it was immersed in a palladium catalyst tank made of a mixture of palladium chloride and tin chloride, washed with water, and then immersed in a 10-20% sulfuric acid bath to remove the remaining tin to remove the remaining tin. Electrical conductivity is given to the cushion sheet surface through electroless plating (S400), which performs electrolytic nickel plating, electroless copper chloride plating, electroless copper sulfate plating, electroless nickel plating, and second electroless nickel plating. Then, using an auto die cutting machine (auto die cutting machine) to form a sheath cutout on the surface of the cushion sheet plated with the metal layer, the conductive resin is applied to the end surface of the cut through the conductive resin barrel W and curing, which is coated and dried to the carbon black slurry to the surface of the plating layer, and can be prepared a cushion sheet having an electromagnetic wave shielding property of the conductive mesh in a manner that the double-sided tape bonded to the rear surface thereof.

Example 2

In coating a foamed polyurethane cushion sheet with a vacuum sputtering equipment on the surface of the cushion sheet, the atmospheric pressure atmosphere of the vapor deposition chamber is controlled to 10 ^-3 to 10 ^-5 torr, and copper (Cu) After imparting electrical conductivity by sputtering the cushion sheet in an argon (Ar) gas atmosphere in which a metal such as nickel (Ni) is ionized, the metal layer is plated using an auto die cutting machine. A sheath cutout is formed on the cushion sheet surface, a conductive resin is applied to the cut surface of the cut through the conductive resin barrel and cured, and carbon black is coated in a slurry state on the surface of the plating layer, and the conductive mesh double-sided tape is coated on the back surface thereof. It is possible to manufacture a cushion sheet having electromagnetic shielding properties by the bonding method.

As described above, the method for manufacturing an electromagnetic wave shielding cushioning material according to the present invention includes a conductive resin at the same time as a minimum amount of conductive resin on only the cut-out section of the cushion sheet so as to shield electromagnetic waves while maintaining the elastic properties of the cushion sheet. It can protect the LCD for wireless communication from external shock while preventing foreign substances from entering the internal circuit, while reducing the manufacturing cost of the electromagnetic shielding cushion sheet that can shield electromagnetic waves and static electricity, There is an effect that can be easily produced as a cushion sheet.

Claims (14)

Forming a metal layer on the cushion sheet surface to impart electrical conductivity; Molding a sheath incision on the cushion sheet; Coating and forming a conductive resin layer on the cut end surface of the sheath cutout; Removing the conductive resin on the cushion sheet surface and curing the conductive resin on the sheath cutout; Forming a surface conductive layer on one front surface of the cushion sheet; A method of manufacturing a cushion sheet having electromagnetic shielding characteristics comprising the step of forming a conductive tape layer on the other front surface of the cushion sheet. The method of claim 1, The cushion seat is a cushion seat having electromagnetic shielding characteristics, characterized in that it is made of any one of foamed rubber, foamed polyurethane, foamed neoprene, and foamed polyolefin. Method of preparation. The method of claim 1, A method for producing a cushion sheet having electromagnetic shielding characteristics, characterized in that the metal layer is formed on the surface of the cushion sheet by electroless plating. The method of claim 3, wherein In electroless plating, the cushion sheet is subjected to a pretreatment step having an ultrasonic cleaning process, an etching process, a catalytic process, a water washing and a tin removing process, an electroless nickel plating and an electroless copper chloride plating, an electroless copper sulfate plating, an electrolytic nickel plating, and an electroless plating. A method of manufacturing a cushion sheet having electromagnetic shielding characteristics, characterized in that to be formed by sequentially performing a plating step having a nickel plating process. The method of claim 1, A method for manufacturing a cushion sheet having electromagnetic shielding characteristics, characterized in that the metal layer is formed on the surface of the cushion sheet by vacuum deposition. The method of claim 5, Vacuum deposition is a PVD (Physical Vaporation Deposition) method, which controls the chamber to a vacuum of 10 ^-3 torr or less at atmospheric pressure, and cushions atoms and molecules of metals to ionize and deposit argon gas (Ar gas). A method for producing a cushion sheet having electromagnetic shielding characteristics, characterized by adsorbing on a sheet surface. The method of claim 1, The conductive resin layer contains 80 to 90 conductive metal powders such as copper (Cu), nickel (Ni), aluminum (Al), copper, and coated silver (Cu + Ag) in 10 to 20% by weight of synthetic resin such as urethane or acryl. Mix by weight, and further mix the curing agent (2.5-5% by weight), the antisettling agent (2.5-5% by weight), the thickener (2-5% by weight), as an additive to the mixture, Method for producing a cushioning sheet having an electromagnetic shielding characteristics characterized in that the formulation. The method of claim 1, The surface conductive layer is formed of a carbon black coating layer, characterized in that the cushion sheet having an electromagnetic shielding characteristics. The method of claim 8, The carbon black coating layer is mixed with 10 to 20% by weight of carbon black powder, 10 to 20% by weight of liquid polyurethane resin, and 60 to 80% by weight of methyl ethyl ketone (MEK) to have a viscosity of 2000 to 5000 cps. A method for producing a cushion sheet having electromagnetic shielding characteristics, characterized in that the liquid is prepared by applying to the surface of the cushion sheet. The method of claim 8, The carbon black coating layer is formed with a thickness of 10 to 50μm method for producing a cushion sheet having an electromagnetic shielding characteristics. The method of claim 1, The surface conductive layer is formed by attaching a conductive fabric to the surface of the cushion sheet with a conductive adhesive, characterized in that the cushion sheet having electromagnetic shielding characteristics. The method of claim 1, The surface conducting layer is formed by attaching an aluminum foil to the surface of the cushion sheet with a conductive adhesive, characterized in that the cushion sheet having electromagnetic shielding characteristics. The method of claim 1, The conductive tape layer is made of a conductive mesh tape made of a metal material, characterized in that the cushion sheet having electromagnetic shielding characteristics. The method of claim 1, The conductive tape layer is made of an inorganic conductive double-coated tape, characterized in that the cushion sheet having electromagnetic shielding characteristics.

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