KR20110088779A - Conductive pad and method for manufacturing conductive pad - Google Patents

Abstract

PURPOSE: A conductive pad and a method for manufacturing the conductive pad are provided to enhance ground properties by securing flexibility and high electricity while securing a thin film structure. CONSTITUTION: A conductive pad comprises a sheet compressing a foam sponge(20) and a plating layer(30) coated on the sheet. The conductive pad comprises further nonwoven fabric attached to at least one side of the sheet. The conductive pad includes a resin layer coated on the surface of the sheet. The conductive pad has the structure where nickel, copper and nickel are electroless plated. A method for preparing the conductive pad comprises the steps of: preparing a thin film sheet by compressing foam urethane raw fabrics; and plating metals on the sheet.

Description

Conductive pad and manufacturing method therefor {CONDUCTIVE PAD AND METHOD FOR MANUFACTURING CONDUCTIVE PAD}

The present invention relates to a conductive pad for electromagnetic shielding or electrical contact and a method of manufacturing the same.

In general, cushion pads having various structures are used for electromagnetic shielding or electrical contact. The cushion pad not only has low surface resistance but also requires excellent flexibility and elastic restoring force so as to increase adhesion to electronic devices.

Representatively, foam gaskets having a cushioning material wrapped therein with conductive fibers are most widely applied. These products have a somewhat insufficient shielding effect because they exhibit a shielding effect by the fabric itself when manufactured into a thin film. In addition, due to the thickness of the sponge inserted into the thin film manufacturing, there is no way to exert elasticity as a gasket in compression and restoring force.

The shielding material as a thin film material has such drawbacks, and thus uses products such as silicon pads and polyolefins, which are insufficient in achieving satisfactory and stable properties in terms of price and properties.

The silicon pad has a disadvantage that the product is expensive due to the composition of expensive materials in manufacturing, and a conductive effect may be obtained by mixing conductive powder (Powder) in the resin to exert a conductive effect for each part.

In addition, the olefin sheet has a limitation in shielding effect because it is energized by passing through the perforated hole, there is a disadvantage that does not exhibit excellent characteristics in cushioning and elastic restoring force of the sheet.

Accordingly, the present invention provides a conductive pad and a method of manufacturing the same, which are capable of increasing ground performance by securing flexibility and high elasticity while having a thin film structure.

In addition, the present invention provides a conductive pad and a method of manufacturing the same, which are capable of enhancing electromagnetic shielding effects due to excellent conductivity.

To this end, the conductive pad may include a sheet compressed with a foam sponge and a plating layer coated on the sheet.

The sheet may further include a nonwoven fabric attached to at least one surface.

The sheet may be a urethane sponge of polyether or polyester component.

Thus, the cushioning property of the urethane property itself can increase the adhesion to the electronic device, it is possible to obtain excellent shielding performance and grounding performance through the entire plating layer of the sheet.

The plating layer may have a structure in which nickel, copper, and nickel are sequentially electroless plated.

The sheet may further include a resin layer coated on the surface.

The resin layer may be a polyacrylate emulsion resin or a polyurethane resin.

On the other hand, the present manufacturing method for manufacturing a conductive pad may include the step of manufacturing a sheet of a thin film by compressing the foamed polyurethane fabric slit the foamed urethane block, and may include the step of plating a metal on the sheet.

The method may further include the step of laminating a nonwoven fabric on one side while heating and melting the foamed urethane fabric in the sheet manufacturing step.

The method may further include attaching a nonwoven fabric to one surface of the urethane foam in the sheet manufacturing step.

The plating of the metal may include etching the sheet fabric to form fine irregularities on the surface of the fibers forming the sheet, subjecting the fibers to susceptibility, activating, first plating to strengthen plating adhesion, and increasing conductivity. It may include a secondary plating step for, a third plating step for suppressing the corrosion of the plating surface.

The primary plating step may be a structure for plating nickel.

The secondary plating step may be a structure for plating copper.

The third plating step may have a structure of plating nickel or plating gold or silver.

In addition, the manufacturing method may further include coating a polymer resin on the sheet subjected to the plating process.

The coating step may be a process of impregnating and drying the sheet in the polyacrylate emulsion resin. The coating step may be a structure for coating a polyurethane resin.

In addition, the manufacturing method may further include a process of imparting flame retardancy to the sheet in the coating step.

As described above, according to the present embodiment, the conductivity is excellent, the flexibility and the high elasticity, the adhesion to the object is excellent, the electromagnetic shielding effect is high and the electrical contact is excellent.

In addition, it does not generate debris during the cutting process it is possible to ensure the stability of the part.

In addition, it is possible to increase the competitiveness as a next-generation conductive component material that is slimming in the future by applying a thin film gasket as a substitute for the thin film gasket to achieve excellent thinning of the product compared to the excellent electromagnetic shielding performance and to exhibit excellent elasticity and resilience under the thin film material.

1 is a schematic cross-sectional view showing a conductive pad according to an embodiment of the present invention.
2 is a flowchart illustrating a manufacturing process of a conductive pad according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

The drawings are schematic and illustrate that they are not drawn to scale. The relative dimensions and ratios of the parts in the figures have been exaggerated or reduced in size for clarity and convenience in the figures and any dimensions are merely exemplary and not limiting. And the same structure, element or part that appears in more than one figure the same reference numerals are used in different embodiments to indicate corresponding or similar features.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the term "comprising" embodies a particular characteristic, region, integer, step, operation, element, and / or component, and other specific characteristics, region, integer, step, operation, element, component, and / or group. It does not exclude the presence or addition of.

Embodiments of the invention described with reference to a perspective view specifically illustrate an ideal embodiment of the invention. As a result, various variations of the illustration, for example variations in the manufacturing method and / or specification, are expected. Thus, the embodiment is not limited to any particular form of the depicted area, but includes modifications of the form, for example, by manufacture. The regions shown in the figures are only approximate in nature, and their forms are not intended to depict the exact form of the regions and are not intended to narrow the scope of the invention.

1 is a schematic cross-sectional view showing a conductive pad according to the present embodiment.

As shown in the drawings, the conductive pad 10 includes a sheet 20 having a structure in which a foamed sponge is compressed, and a plating layer 30 coated on all the fibers of the sheet 20. In addition, a nonwoven fabric 22 is further attached to at least one surface of the sheet 20.

The sheet 20 is made of a polyether-based or polyester-based foam sponge block. The material of the sheet 20 is not limited thereto and may be selected from various materials. The sheet 20 is manufactured by slitting a foam sponge block to fabricate it, and compressing the foam sponge fabric through a heat press process. This will be explained later.

The nonwoven fabric 22 is to reinforce the rigidity of the sheet 20 of the compressed sponge structure made of a thin foil of sponge material. That is, the sheet 20 is a sponge-like thin film, and its own rigidity is weak, so that there is a high risk of breakage during tearing due to tearing or excessive elongation. The sheet 20 is attached to one side of the nonwoven fabric 22 to prevent tearing and to properly control the generation of tensile force due to excessive elongation.

In this embodiment, the nonwoven fabric 22 is laminated in the process of heating the foam sponge fabric to melt the surface.

That is, the foam sponge is heated to melt to laminate the surface. At this time, the melting thickness of the foam sponge fabric is 0.25mm ~ 0.5mm and can be increased or decreased to 1mm according to the situation.

As such, while melting the surface under high temperature, the nonwoven fabric 22 is laminated on the foamed sponge fabric.

In this embodiment, the nonwoven fabric 22 has a structure in which the foamed sponge fabric is melted and attached thereto, but is not limited thereto. For example, the nonwoven fabric 22 may be attached to the foamed sponge fabric through an adhesive. The nonwoven fabric 22 is laminated to a foamed sponge fabric without an adhesive or laminated using an adhesive may vary depending on whether the foamed sponge used is polyester or polyether based. In the case of attaching the nonwoven fabric 22 by using an adhesive, the work should be performed so that there is no heterogeneity such as restoring force and strength under a thin film state as a heterogeneity with the foamed sponge fabric.

The adhesive may be variously applied, such as acrylic or urethane or rubber.

In this embodiment, the foamed sponge fabric to which the nonwoven fabric 22 is attached using a laminating operation or an adhesive is compressed into a compressed sponge structure sheet 20 through a heat press operation.

Here, the conductive pad 10 has a structure in which a metal plating layer is formed on the sheet 20 in the sheet 20 having the above-described structure.

In the present embodiment, the plating layer 30 has a structure in which three plating layers are stacked. That is, the plating layer 30 has a structure in which the nickel plating layer 32, the copper plating layer 34, and the nickel plating layer 36 are sequentially stacked and plated. Nickel is plated on the sheet 20 to form a nickel plated layer 32 and copper is plated on the outside thereof to form a copper plated layer 34, and nickel is plated on the outside to form a nickel plated layer 36.

In addition, the plating layer 30 may have a structure in which the outermost plating layer is plated with gold or silver. Finally, by plating gold or silver on the outermost plating layer instead of nickel, it is possible to further increase electromagnetic shielding effects and to prevent corrosion.

The plating layer 30 is formed by electroless plating nickel and copper and nickel (or gold or silver) sequentially. The plating layer 30 is formed on the sheet 20 to a thickness of 0.001mm ~ 0.08mm. If the thickness of the plating layer 30 is less than 0.001mm, the adhesion between the plating layer and the sheet material is weak, and thus the electrical resistance value does not reach the commercialization level. The function will fall.

The sheet has a structure in which the foam sponge is compressed through a heat press operation, and the occurrence of particle debris and the falling of metal particles after plating may be a factor that hinders the stability of the component. Therefore, there is a need to prevent the occurrence of such debris.

Accordingly, the conductive pad 10 has a structure in which a resin layer 40 is formed by coating a polymer resin on the fibers of the sheet 20. Therefore, the polymer resin firmly holds the sponge cells forming the sheet when cutting the sheet so that cutting chips do not occur. In addition, it is possible to prevent the contamination and damage of the plating layer to impart the stability of the product.

In the present embodiment, the polymer resin forming the resin layer 40 may be a polyacrylate emulsion resin or a polyurethane resin.

In addition, the resin layer 40 may further include a flame retardant 42. The flame retardant 42 is made of bromine or antimony trioxide or phosphorus or melamine or aluminum hydroxide. The flame retardant 42 is mixed with the polymer resin when the resin layer 40 is formed and coated on the fiber. Alternatively, for the physical properties of the product after flame retardant, it is possible to proceed using a liquid raw material rather than a solid raw material.

In addition, in the case of the structure using the sponge to which the urethane sponge itself is given a flame retardancy during the progress of the flame retardant, it is possible to proceed by giving the flame retardancy as such without additional use of other flame retardant raw materials.

As described above, the conductive pad 10 compresses the urethane sponge to secure flexibility and high elasticity by its component structure, and obtains excellent electromagnetic shielding effect by forming a plating layer 30 by plating a metal on the entire sheet. do.

In addition, the conductive pad 10 further includes a conductive adhesive layer 50 coated on one surface of the sheet 20.

The conductive adhesive layer 50 is to more easily use the conductive pad 10 having the above-described structure, and may be formed on only one surface of the sheet 20 or on only both surfaces or a specific portion required by a customer.

The electroconductive adhesive which comprises the said electroconductive adhesive layer is an adhesive which metal powder, such as nickel, copper, or silver, was added to the conductive base material, such as the conductive fiber mesh, the conductive nonwoven fabric 22, or aluminum foil or copper foil. Of course, the inorganic adhesive without the said conductive base material is also included. The pressure-sensitive adhesive may be acrylic or silicone-based and adhered onto the sheet 20 in the form of a double-sided tape. Reference numeral 52 is a release paper attached to the outer surface of the conductive adhesive layer (50).

Thus, the pad 10 can be used simply by removing the release paper 52 and attaching the conductive pad 10 to the required position via the conductive adhesive layer 50.

Hereinafter, a manufacturing process of the conductive pad will be described with reference to FIG. 2.

In the conductive pad 10 according to the present embodiment, the nonwoven fabric 22 is laminated on a foamable sponge and compressed to manufacture a sheet, and then the metal is plated on the manufactured sheet 20 and the resin is coated and dried. .

Looking at the manufacturing process of the sheet first, the material is fabricated through a peeling (feeling) process to cut and roll the foam sponge block.

The prepared foam sponge fabric is melted to laminate the surface of the fabric by indirect heat of 200 ~ 230 ℃. Then, the nonwoven fabric 22 is laminated while melting the surface of the fabric under high temperature.

The foamed sponge fabric in which the nonwoven fabric 22 is laminated is subjected to a process of compressing the sheet by performing a heat press operation for 2 to 2.5 minutes at a pressure of about 2500KG at a temperature of 160 to 240 ° C. The process conditions are press pressurization times when the thickness of the sponge is working at a level of 0.7 mm, and pressurization times are different when the thickness to be manufactured is different from the above. Compressing the sponge at a ratio of approximately 340% shows the best characteristic of the performance of the compressed sponge, and the ratio can be increased or decreased depending on the thickness specification of the manufactured compressed sponge.

When the sheet 20 is manufactured as described above, the surface of the sheet 20 undergoes an etching process to form fine concavities and convexities (S100 to S110).

The etching process is performed for 4 to 5 minutes in an aqueous alkali solution (NaOH) at a concentration of 4 to 6% of 80 ~ 90 ℃. After the etching process, the etching solution is removed by washing with water and subjected to a Sensitining process on the fibers. (S120) The susceptible treatment process is performed by adding filadium chloride and hydrochloric acid to water at 35 ° C. and mixing the sheet in a solution. It is made by immersing 20 for about 5 minutes.

When the susceptible treatment process is completed, the water treatment process removes the susceptible treatment solution and proceeds with the activation process. The activation process is a step of coating palladium by immersing the sheet 20 in a mixed solution containing palladium chloride and hydrochloric acid for about 5 minutes.

When the activation process is completed, the treatment solution is removed by washing with water, and the plating layer 30 is formed on the sheet 20 fibers.

In this embodiment, the plating layer 30 proceeds through a third process. The primary plating process is to enhance the plating adhesion. The sheet is immersed in a mixed solution of nickel sulfate, sodium hypophosphite, sodium citrate, and stabilizer at about 45 ° C. for about 20 minutes to form a nickel plating layer on the fiber by electroless plating. (S140)

After the primary plating process is completed, the water washing process is performed, and then the secondary plating process is performed to increase conductivity. In the secondary plating process, the sheet is immersed in a mixed solution of copper sulfate solution and formalin caustic soda at 45 to 55 ° C. for 20 to 30 minutes to form a copper plating layer by electroless plating.

After the second plating process is completed, the water washing process is performed, and then the third plating process is performed to suppress the corrosion of the plating surface. In the third plating process, the sheet is immersed in a mixed solution of nickel sulfate, sodium hypophosphite, sodium citrate, and stabilizer at 45 ° C. for 20 minutes to form a nickel plating layer by electroless plating.

After the third plating process is completed, the washing process is followed by drying.

According to another embodiment of the present manufacturing method, by performing a process of plating gold or silver in addition to nickel during the third plating process, it is possible to further enhance the electromagnetic shielding effect and the corrosion protection effect.

The sheet is completed the plating process is subjected to a polymer resin impregnation process to prevent the generation of debris during cutting, which is a disadvantage of the sponge structure (S170).

The resin impregnation process is performed by impregnating a sheet for 1 minute in a solid content 40% polyacrylate emulsion (Polyacrylate Emulsion) resin of 5 ~ 40 ℃. The fiber surface of the sheet on which the plating layer is formed is coated with a polymer resin.

As described above, the sheet of the compressed sponge-like sheet is coated with a polymer resin, so that each cell structure of the sponge is firmly held by the polymer resin when the sheet is cut, so that cutting chips do not occur.

Here, the resin impregnation step may use a polyurethane resin of 5 to 40 ° C in addition to the polyacrylate emulsion. In this case, the fiber surface of the sheet is coated with a polyurethane resin and its working effect is the same.

In addition, according to the present embodiment, the flame retardant may be coated together on the sheet fiber during the resin impregnation process. To this end, the resin impregnation process is performed by impregnating a sheet in a resin solution in which the polyacrylate emulsion resin and the flame retardant are mixed.

The flame retardant may be selected from one or two or more of components such as bromine or antimony trioxide or phosphorus or melamine or aluminum hydroxide.

In the case of a liquid flame retardant it is easy to mix with the resin, but it is difficult to apply a variety of types of flame retardant is used alone, in this case, the flame retardant effect may be insufficient.

Therefore, this embodiment uses a mixture of various kinds of powdery inorganic flame retardant. Further, in order to increase the flame retardancy, the inorganic flame retardant may be further crushed into fine particles using the three rollers. The inorganic flame retardant pulverized into fine particles can be further dispersed evenly throughout the resin when mixed with the resin to further improve the flame retardant effect of the sheet.

When the resin impregnation process is completed, the sheet is passed through a drying furnace and dried at a temperature of 100 ~ 150 ℃. (S180)

The conductive compressed sponge pad is produced by volatilizing the solvent or water of the resin remaining on the sheet while passing through the drying furnace and remaining only the solid content.

The sheet moving speed and temperature in the drying furnace are appropriately set according to the thickness and size of the sheet of the compressed sponge structure and the solid content of the resin.

The conductive pad manufactured by the above process is made of a slim compressed sponge structure, has cushioning, compressive restoring force, flexibility and tensile force, and exhibits excellent electrical conductivity by the coating layer coated on the whole.

Table 1 below is a chart showing the results of the resistance measurement test for the pad according to the present embodiment.

Measurement count 1 time Episode 2 3rd time 4 times Vertical resistance (Ω) Seat alone 0.013 0.011 0.015 0.019 Adhesive treatment 0.041 0.038 0.035 0.039 Horizontal resistance (Ω) Seat alone 0.029 0.021 0.028 0.026 Adhesive treatment 0.024 0.029 0.027 0.023

The experiment was carried out using a test piece cut into a rectangular pad having a vertical resistance of 30 mm in length and 30 mm in width, and a horizontal resistor of 50 mm in length and 50 mm in width. The experiments were conducted for two types of vertical and horizontal resistors respectively.

The measurement of the vertical resistance value was performed by placing the test piece on the lower copper plate, the upper copper plate on the test piece, and connecting a measuring device for resistance measurement between the upper copper plate and the lower copper plate in series. And the measuring method was made by pressing the upper copper plate placed on the test piece to the test piece with a weight of 1kg and measuring the resistance value at that time after 1 minute elapsed.

The measurement of the horizontal resistance value is carried out by placing the test pieces on two lower copper plates spaced apart, and placing two upper copper plates which are also spaced apart on each lower copper plate, and measuring the resistance measuring device between the two lower copper plates in series. It was done by connecting. And the measuring method was made by pressing each of the upper copper plate to the test piece with a weight of 0.8kg and measuring the resistance value at that time after 1 minute elapsed.

As shown in Table 1, as a result of performing all four experiments, it can be seen that both the vertical resistance and the horizontal resistance are extremely low. As described above, the pad according to the present embodiment has excellent flexibility and high elasticity, but also excellent conductivity.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

10: pad 20: sheet
22 nonwoven fabric 30 plating layer
32: nickel plated layer 34: copper plated layer
36: nickel plated layer 40: resin layer
42: flame retardant

Claims (9)

The sheet which compressed the foam sponge,
Plating layer coated on the sheet
Conductive pad comprising a. The method of claim 1,
The sheet further comprises a nonwoven fabric attached to at least one side. The method according to claim 1 or 2,
A conductive pad further comprising a resin layer coated on the surface of the sheet. The method of claim 3, wherein
The plating layer is a conductive pad of the electroless plating of nickel, copper, nickel in order. Compressing the urethane foam to prepare a sheet of thin film,
Plating metal on the sheet
Conductive pad manufacturing method comprising a. The method of claim 5, wherein
Conductive pad manufacturing method further comprising the step of laminating a nonwoven fabric on at least one surface of the urethane foam in the sheet manufacturing step. The method according to claim 5 or 6,
The method of manufacturing a conductive pad further comprising coating a polymer resin on a sheet after the plating layer is formed. The method of claim 7, wherein
The plating layer forming step
Etching the sheet to form fine irregularities on the surface of the sheet, subjecting the fibers to susceptibility, activating, first plating to enhance plating adhesion, second plating to increase conductivity, and inhibiting corrosion of the plating surface. Conductive pad manufacturing method comprising a third plating step for. The method of claim 8,
The polymer resin coating step is a conductive pad manufacturing method to give a flame retardance to the sheet by further mixing the flame retardant material to the polymer resin coating material.

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