KR20060036883A - Electrically conductive paint compositions and preparation method thereof - Google Patents

Abstract

The present invention relates to a conductive paint composition for shielding electromagnetic waves and a method of manufacturing the same that can effectively solve the electromagnetic interference (EMI) and RFI (Radio Frequency Interference) caused by electromagnetic waves generated from the internal devices of various electronic devices, Conductive paint compositions according to the present invention can provide excellent conductive properties, viscosity properties, device adhesion and wear resistance, including waterborne polyurethane dispersions comprising aliphatic and aromatic functional groups.

Electromagnetic shielding, conductive paint, polyurethane dispersion, metal powder, solvent, aromatic functional group, aliphatic functional group

Description

Conductive paint composition and its manufacturing method {ELECTRICALLY CONDUCTIVE PAINT COMPOSITIONS AND PREPARATION METHOD THEREOF}

        The present invention relates to a conductive paint composition for shielding electromagnetic waves and a method for manufacturing the same. More particularly, the present invention relates to a conductive paint composition including a metal powder as the conductive material and to an aqueous polyurethane dispersion prepared by mixing aliphatic and aromatic polyacids. The present invention relates to a conductive paint composition excellent in properties, viscosity properties, device adhesion and wear resistance, and a method for producing the same.

        Electromagnetic waves generated from internal devices of various electronic devices such as mobile communication terminals, notebook PCs, office equipment, and medical devices may affect various diseases such as headache, visual acuity, leukemia, brain tumors, circulatory disorders, reproductive function, and VDP syndrome. It has been reported that it can be crazy, and controversy over the harmful effects of electromagnetic waves on the human body. In addition, as the degree of integration of devices increases due to the lighter weight of electronic products, electromagnetic noise generated from each component may cause peripheral devices to malfunction, thereby causing device failure. Recently, EMI (Radio Frequency Interference) and RFI (Electromagnetic Interference) and RFI (Radio Frequency Interference) have been strengthened, as well as strengthening the shielding standard against electromagnetic waves generated from home, office, and industrial electronic products such as computers, cordless phones, automobiles, medical devices, and multimedia players. Regulations on emission are being tightened, and electromagnetic wave shielding measures for various electronic devices and components are emerging as important issues.

        Common shielding methods for blocking electromagnetic waves include plating, vacuum deposition, and spray coating. Electromagnetic shielding method by plating has been used for a long time, but the manufacturing cost is high, the production process is complicated, and there is a problem that causes environmental pollution, it is required to compensate for this. On the other hand, the electromagnetic shielding method by vacuum deposition is used only when the cost is very high and the long-term reliability is a problem is extremely limited. On the other hand, electromagnetic shielding technology by spray coating using metal powder is widely used because it is easy to apply and can solve environmental problems.

        The spray coating method is spray coating a coating liquid containing a mixture of an adhesive resin and a conductive metal on a substrate, and the conductive coating film obtained by spray coating should have excellent base adhesion and wear resistance. If a part of the metal powder or the coated conductive film is peeled off and then falls on the circuit of the electronic device after being coated inside the electronic device, operation of the electronic device may be disturbed. This is especially true for spray coatings using relatively large silver coated copper powder.

        Due to the nature of the manufacturing process of mobile phones and notebooks, the conductive paint is coated and passed through the hands of several workers in the process of assembling the finished product. For example, after coating, measuring resistance, inspecting the appearance, attaching parts, attaching a substrate, and assembling, etc., may cause scratches on the coated surface. Therefore, abrasion resistance of the coated conductive film is also strongly required. It is one of the characteristics.

        In the spray coating method using metal powder, conductive paint is prepared using metal powder such as silver powder, nickel powder, aluminum powder, etc. on the powder, and sedimentation of the metal powder after the paint is manufactured due to the density difference between the metal powder and the remaining components. This can occur more easily than other paints. After the sedimentation of the metal powder occurs and the solution of the metal and the paint is separated, it is difficult to recover the uniform dispersion state at the initial stage of the paint production even after stirring. Therefore, the conductive paint composition including the metal powder should have high viscosity characteristics. Increasing the viscosity of the conductive paint can prevent sedimentation of the metal, thereby maintaining the initial uniform dispersion state for the long term and exhibiting the same physical properties, thereby increasing the viscosity of the conductive paint.

        As a method of shielding electromagnetic waves by spray coating, U. S. Patent No. 6,645, 613 discloses a conductive coating composition comprising a water-dispersed polyurethane dispersion having only an alkyl chain structure. However, the aqueous polyurethane dispersion of the alkyl chain structure used in the U.S. Patent does not cause yellowing due to sunlight or ultraviolet rays, but has low cohesion between chains compared to the chain structure having an aromatic functional group, resulting in poor device adhesion and wear resistance. Problem, and the viscosity characteristic is insufficient to maintain a uniform dispersion state of the metal powder.

The present invention is to overcome the above-described problems of the prior art, one object of the present invention is to introduce a water-dispersible polyurethane dispersion having an aromatic functional group to prepare a high viscosity conductive paint and to coat the device after coating / drying of the metal It is to provide a conductive paint composition having improved device adhesion and wear resistance of the conductive film.

Another object of the present invention is to provide a method for producing a conductive film for shielding electromagnetic waves, which can provide a conductive film excellent in device adhesion and wear resistance.

Still another object of the present invention is to provide an electromagnetic shielding conductive film having excellent electromagnetic shielding performance and excellent wear resistance.

One aspect of the present invention for achieving the above object is in a conductive paint composition comprising a water-dispersed polyurethane disulsion, a metal powder, a solvent and a rheology control agent, wherein the water-dispersed polyurethane disper It relates to a conductive paint composition comprising a water dispersible polyurethane resin:                         

Wherein R ¹ is an aliphatic hydrocarbon having 4 to 12 carbon atoms, a cyclic aliphatic hydrocarbon having 6 to 15 carbon atoms, or a mixture thereof; R ² is an aliphatic hydrocarbon having 2 to 12 carbon atoms; R ³ is an aliphatic hydrocarbon having 2 to 20 carbon atoms and an aromatic hydrocarbon having 6 to 20 carbon atoms; R ⁴ and R ⁵ are hydrogen or a methyl group; R ⁶ is an aliphatic hydrocarbon having 3 or 4 carbon atoms; R ⁷ is hydrogen or an aliphatic hydrocarbon having 1 to 9 carbon atoms; R ⁸ is an aliphatic hydrocarbon having 1 to 10 carbon atoms, a cyclic aliphatic hydrocarbon having 3 to 10 carbon atoms, or a mixture thereof; the ratio of n1: (n2 + n4 + n6): n3: n4 is 0.2-1.5: 1.0-3.0: 0.01-0.3: 0.1-1.0; n5 is 0.1 to 1.0, x is 1 to 20, the sum of y and z is 5 to 200,

The polyurethane resin includes repeating units wherein R ³ is an aromatic hydrocarbon and repeating units where R ³ is an aliphatic hydrocarbon.

        Another aspect of the present invention relates to a method for producing a conductive film for shielding electromagnetic waves, comprising applying the conductive paint composition on a substrate and drying the applied substrate by heat treatment in a drying furnace.

Another aspect of the present invention for achieving the above object relates to an electromagnetic wave shielding conductive film produced by the conductive paint composition of the present invention.

        Hereinafter, the present invention will be described in more detail.

        The conductive paint composition according to the present invention comprises a water dispersion polyurethane dispersion, a metal powder, a mixed solvent, and may optionally further include a rheology control agent as necessary. In addition, the composition ratio of each component in the conductive paint composition of the present invention is 0.1-60 wt% of water dispersion polyurethane dispersion; Metal powder: 10-60wt%; And solvent: 10-60 wt%.

        In the present invention, the water-dispersed polyurethane dispersion attaches a metal powder that imparts conductivity to the device to be coated and gives a wear resistance that the conductive film can withstand scratches after drying.

        In general, polyurethane has excellent flexibility, rebound elasticity, wear resistance, and has strong adhesiveness, so that it is used in many fields requiring adhesiveness. Polyurethanes for use in conventional adhesives, coatings and the like were mainly produced and used in an oily state. Polyurethane prepared in an oily state uses an organic solvent such as methyl ethyl ketone (MEK), dimethylformamide, toluene, etc. as a solvent in order to use at an appropriate viscosity. As such, when the organic solvent is used as a solvent, it causes environmental pollution such as air and water, lowers the health and productivity of workers, and has a risk of fire by using an organic solvent having a very low flash point.

        Due to this problem, a self-emulsifying method for synthesizing a water-dispersed polyurethane dispersion that imparts ionic groups to a polyurethane backbone has been developed.A method of using a cationic ionomer among the methods for imparting ionic groups to a polyurethane backbone is US patent. 4,016,123, 4,190,567, 4,277,383, and Japanese Patent Laid-Open No. 5-320331, and the like, and the method of using an anionic ionomer is disclosed in US Pat. There is a method disclosed in US Pat. No. 4 and the like, and a method disclosed in US Pat. No. 4,794,147 is used.

        Water-dispersed polyurethane dispersions can also be classified according to the type of polyol used in the polymerization, and are broadly classified into polyether, polyester and acrylic. Among them, polyester-based polyols that exhibit strong adhesion to various devices and have excellent mechanical properties such as wear resistance are frequently used. Polyester-based polyols are synthesized by reacting polyacids with polyhydric alcohols. The polyacids used in the synthesis may be aliphatic adipic acid, aromatic benzoic acid, isophthalic acid, terephthalic acid phthalic anhydride or trimethyl anhydride. have.

        In the present invention, a polyester-based polyol having strong cohesion and abrasion resistance of a functional period, which is an advantage of aliphatic, and an aromatic polyacid, may be obtained by mixing aliphatic polyacid and aromatic polyacid in synthesizing the polyol. Therefore, the conductive paint composition including the water-dispersed polyurethane dispersion prepared using such a polyol may have excellent device adhesion and wear resistance after drying.

        The water-dispersed polyurethane dispersion used in the present invention is a water-dispersed polyurethane dispersion synthesized by mixing aromatic polyacids and aliphatic polyacids, and has a structure of the following Chemical Formula 1.

[Formula 1]

Wherein R ¹ is an aliphatic hydrocarbon having 4 to 12 carbon atoms, a cyclic aliphatic hydrocarbon having 6 to 15 carbon atoms, or a mixture thereof; R ² is an aliphatic hydrocarbon having 2 to 12 carbon atoms; R ³ is an aliphatic hydrocarbon of 2 to 20 carbon atoms or an aromatic hydrocarbon of 6 to 20 carbon atoms; R ⁴ and R ⁵ are hydrogen or a methyl group; R ⁶ is an aliphatic hydrocarbon having 3 or 4 carbon atoms; R ⁷ is hydrogen or an aliphatic hydrocarbon having 1 to 9 carbon atoms; R ⁸ is an aliphatic hydrocarbon having 1 to 10 carbon atoms, a cyclic aliphatic hydrocarbon having 3 to 10 carbon atoms, or a mixture thereof; the ratio of n1: (n2 + n4 + n6): n3: n4 is 0.2-1.5: 1.0-3.0: 0.01-0.3: 0.1-1.0; n5 is 0.1 to 1.0; x is 1 to 20, the sum of y and z is 5 to 200,

The polyurethane resin is characterized by comprising a repeating unit of R ³ is an aromatic hydrocarbon and a repeating unit of R ³ is an aliphatic hydrocarbon.

     Specific examples of the water-dispersed polyurethane dispulsion of the formula (1) usable in the present invention include Reactisol PS-3 of Ortec. In the present invention, the mixing ratio of the aromatic polyacid and the aliphatic polyacid can be in the range of 99: 1 to 1:99.

        The content of water-dispersed polyurethane dispersion in the conductive paint composition of the present invention is 0.2 wt%-60 wt%, preferably 0.5 wt% -40 wt% (based on product weight). If the content is less than 0.2wt%, the adhesion and wear resistance of the device is poor, and if the content exceeds 60wt%, the resistance may increase.

        The metal powder usable in the conductive paint composition of the present invention uses silver powder or silver coated copper powder. In the case of silver powder, flake powder having an average particle size (D50) of 1 to 10 μm is used, and in the case of silver coated copper powder, flake powder having an average particle size (D50) of 5 to 50 μm is used. The amount of the metal powder used in the present invention is 10 wt%-60wt%. If the metal powder is less than 10 wt%, the conductivity is poor, and if it exceeds 60 wt% there is a disadvantage that the manufacturing cost increases. Specific examples of the metal powder that can be used in the present invention may include Ferrosa SF-70A, SF-9ED, SF-7A, SF-7E, SF-9, SF-15-2, HRP company SF-162, and the like. Silver-coated copper powders include Ferrosa AgCu-200, AgCu-250, AgCu-300, AgCu-400 and the like.

        In order to improve the conductivity of the conductive paint composition in the present invention, silver powder having an average particle size of 1-5 μm (hereinafter referred to as “A powder”) and silver powder having an average particle size of 4-10 μm (hereinafter referred to as “B powder”) It is preferable to mix and use. This is interpreted to improve conductivity because particles of different sizes are in good contact with each other. In the case where A powder and B powder are mixed and used, the mixing ratio of A powder and B powder is preferably selected from the range of 99.9: 0.1 to 20:80 (w / w). When the proportion of the B powder in the total silver powder is less than 80% by weight, the conductive synergistic effect to be obtained by mixing different size powders cannot be achieved.

        Examples of mixed solvents usable in the present invention include methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl acetate, methylpyrrolidone, acetone, methyl cellulsolve, ethyl cellulsolve, butyl cellulsolve, In the range of 10 wt% to 60 wt%. Since the main solvent uses a mild solvent rather than a highly corrosive solvent such as methyl ethyl ketone (MEK), it has little effect on the plastic surface and is good in terms of workers' environmental safety. In addition, it is possible to reduce the cost by selecting a solvent having a low boiling point and mass production under low drying conditions after spray coating.

        The conductive paint composition of the present invention may further include a rheology control agent as necessary. The preferred rheology control agent usable in the present invention is an acrylic polymer type, which is soluble in solvents of alcohols and is effective in preventing sedimentation and spray workability of metals without affecting conductivity. A specific example of such a rheology control agent is Carbo-pol EZ-2 manufactured by Noveon. When the rheology control agent is added to the conductive paint composition according to the present invention, the rate of use of the rheology control agent is 0.1 to 20 wt%. If the amount of rheology control agent is less than 0.1 wt%, the thickening effect may be reduced, and sedimentation of the metal may occur. If the amount of the rheology control agent is greater than 20 wt%, the strong interaction with the resin may cause poor storage properties, leading to an increase in the resistance value. This can be

      In another aspect, the present invention relates to a method for producing a conductive film for shielding electromagnetic waves.

In the case of manufacturing the conductive film for electromagnetic wave shielding by the method of the present invention, first, after preparing a conductive paint composition including a polyurethane dispersion, a metal powder, a solvent, and a rheology control agent including the water-dispersible polyurethane resin of Formula 1 It is applied onto a substrate. Subsequently, the base material coated with the conductive paint composition is dried by heat treatment in a drying furnace.

        Substrates usable in the present invention include polycarbonates, polycarbonate alloys, acryl butadiene styrene (ABS), acryl butadiene styrene / polycarbonate copolymers (ABS / PC), polyphenylene sulfite (PPS) resins However, it is not necessarily limited to these.

        In the present invention, the drying step is preferably performed at 40 ~ 70 ℃. Drying below 40 ° C. may result in insufficient drying of the coating film and problems of poor adhesion and resistance, and may require a long time for sufficient drying, leading to a decrease in productivity. In addition, when the drying exceeds 70 ℃ may cause a deformation of the coating substrate and a decrease in the function of the binder resin.

        The conductive film coated on the plastic housing of the mobile phone, notebook PC, etc. by the method of the present invention has excellent device adhesion and excellent wear resistance by using a dispersion of polyurethane dispersion having different functional groups of aliphatic and aromatic groups.

        Hereinafter, the present invention will be described in more detail with reference to Examples. The following examples are merely to explain preferred embodiments of the present invention, and should not be construed as limiting the protection scope of the present invention.

Production Example of Paste of Rheology Control Agent (Cabopol EZ-2)

        950 g of ethanol is added to a container and 20 g of Carbopol EZ-2 is added while stirring at 700 rpm in a high speed stirrer. After 30 minutes of stirring at 800 rpm neutralized with Akzo product name Ethomeen C-25 30 g. After the amine addition, the mixture is stirred for 1 hour at 1000 rpm to finish.

Example 1

        A commercially available silver powder (SF of Ferro, USA) was added after adding 94 g of a water-dispersed polyurethane dispulsion (Reactizol PS-3, Oltec, USA) using Dispermat D-51580 (VMA GETZMANN GMBH). -70 A) was prepared by adding 186 g and stirring at 2000 rpm for 30 minutes. 141 g of ethanol was added thereto, mixed at 500 rpm for 10 minutes, and 57 g of carbopol paste obtained in the above preparation was added thereto, followed by viscosity adjustment while stirring at 1000 rpm for 30 minutes to finish.

        The prepared sample was diluted with 100 vol% of ethanol and spray-coated to a polycarbonate sheet having a width of 15 cm, a length of 6 cm, and a thickness of 2 mm so that the dry film thickness was 12.5 μm, and the coated specimen was dried in a 60 ° C. drying furnace for 15 minutes. It was. Evaluation of the physical properties of the obtained coating specimens are shown in Table 1 below.

Example 2

        Using dispermat D-51580 model (VMA GETZMANN GMBH), add 70 g of Reactazole PS-3 (Alltec, USA), and then add 116 g of silver-coated copper powder (AgCu-200 from Ferro). Prepared by stirring for 30 minutes at 1000 rpm. 279 g of ethanol was added thereto, mixed at 500 rpm for 10 minutes, and 12 g of carbopol paste was added thereto, followed by stirring at 1000 rpm for 30 minutes to finish the viscosity adjustment.

        The prepared sample was evaluated for physical properties in the same manner as in Example 1 and the results are shown together in Table 1 below.

Example 3

        After adding 94 g of Reactazole PS-3 (manufactured by Oltec, USA) using a Dispermat D-51580 model (VMA GETZMANN GMBH), a silver powder having a mean particle size of 2 μm (SF-70A from Ferro, USA) and Silver powder having a mean particle size of 5 μm (SF-10E, manufactured by Ferro, USA) was mixed and prepared by adding 186 g of silver powder and stirring at 2000 rpm for 30 minutes. 141 g of ethanol was added thereto, mixed at 500 rpm for 10 minutes, and 57 g of carbopol paste obtained in the above preparation was added thereto, followed by viscosity adjustment while stirring at 1000 rpm for 30 minutes to finish. The prepared sample was evaluated for physical properties in the same manner as in Example 1 and the results are shown together in Table 1 below.

Comparative Example 1

        Commercially available silver after addition of 94 g of water-dispersed polyurethane dispulsion (Spensol L512 from Reichhold) using only an alkyl chain structure using Dispermat D-51580 model (VMA GETZMANN GMBH) 186 g of a powder (SF-70A from Ferro) was added thereto and stirred at 2000 rpm for 30 minutes. 141 g of ethanol was added thereto, mixed for 10 minutes at 500 rpm, and 57 g of carbopol paste was added thereto, followed by stirring at 1000 rpm for 30 minutes to adjust the viscosity. The prepared sample was evaluated for physical properties in the same manner as in Example 1 and the results are shown together in Table 1 below.

Comparative Example 2

        Commercially available silver coating after adding 70 g of water-dispersed polyurethane dispulsion (Spensol L512 from Reichhold) using only an alkyl chain structure using Dispermat D-51580 model (VMA GETZMANN GMBH) 116 g of the prepared copper powder (AgCu-200 from Ferro) was prepared by stirring at 1000 rpm for 30 minutes. 279 g of ethanol was added thereto, mixed at 500 rpm for 10 minutes, and then 12 g of carbopol paste was added, followed by stirring at 1000 rpm for 30 minutes to finish the viscosity adjustment. The prepared sample was evaluated for physical properties in the same manner as in Example 1 and the results are shown together in Table 1 below.

Comparative Example 3

   Except that the spray-coated specimens were dried for 15 minutes in a 30 ° C drying furnace.

  A sample was prepared in the same manner as in Example 3, the physical properties were evaluated, and the results are shown in Table 1 together.

division Resistance (Ω / □) Adhesion Abrasion Resistance (Speed) Viscosity (cPs) Example 1 Example 2 Example 3 0.010 0.050 0.015 5B 5B 5B 419 530 421 39,500 4,560 37,200 Comparative Example 1 Comparative Example 2 Comparative Example 3 0.015 0.050 0.220 4B 1B 1B 182 197 118 9,300 1,150 37,200

[Property evaluation method]

        * Resistance: The surface resistance per unit area was evaluated using a multimeter.

        Adhesion: evaluated by ASTM D3359.

        Abrasion resistance: Using a Norm Tool Inc. wear tester (RCA Abrader) and a 1/4 inch wide tape, the number of revolutions until the hole formed in the coated conductive film was evaluated.

        * Viscosity: measured with a Brookfield Low Viscosity Viscometer (LVT) viscometer and measurement conditions were measured at 30 RPM using spindle # 3. Viscosity is 10,000

In case of more than cPs, RVT viscometer was used, and the measurement condition was measured at 20 RPM using spindle # 7.

As confirmed through the results of Table 1, the conductive paints prepared using the water-dispersed polyurethane dispersion having only a conventional alkyl chain structure (Comparative Examples 1 and 2) have a low viscosity and a dried conductive While the adhesiveness and the abrasion resistance of the film are poor, a conductive paint containing a water-dispersed polyurethane dispulsion prepared by using a polyester-based polyol prepared by mixing aliphatic and aromatic polyacids as in the present invention (Examples 1 to 2). 3) had a high viscosity of the paint and excellent adhesion to the device and wear resistance of the conductive film.

        The conductive paint composition according to the present invention has a high viscosity of the paint and excellent adhesion to the device and wear resistance of the conductive film, and can block electromagnetic waves of several MHz to several GHz when manufactured as an electromagnetic shielding conductive film. It provides remarkable effects that can effectively solve the problems of electromagnetic interference (EMI) and radio frequency interference (RFI) caused by electromagnetic waves generated from internal devices such as PCs, office equipment, and medical devices.

Claims (13)

In the conductive paint composition comprising a water-dispersed polyurethane dispersion, a metal powder, a solvent and a rheology control agent, the water-dispersed polyurethane disperse comprises a water-dispersible polyurethane resin of the formula  [Formula 1]

Wherein R ¹ is an aliphatic hydrocarbon having 4 to 12 carbon atoms, a cyclic aliphatic hydrocarbon having 6 to 15 carbon atoms, or a mixture thereof; R ² is an aliphatic hydrocarbon having 2 to 12 carbon atoms; R ³ is an aliphatic hydrocarbon having 2 to 20 carbon atoms and an aromatic hydrocarbon having 6 to 20 carbon atoms; R ⁴ and R ⁵ are hydrogen or a methyl group; R ⁶ is an aliphatic hydrocarbon having 3 or 4 carbon atoms; R ⁷ is hydrogen or an aliphatic hydrocarbon having 1 to 9 carbon atoms; R ⁸ is an aliphatic hydrocarbon having 1 to 10 carbon atoms, a cyclic aliphatic hydrocarbon having 3 to 10 carbon atoms, or a mixture thereof; the ratio of n1: (n2 + n4 + n6): n3: n4 is 0.2-1.5: 1.0-3.0: 0.01-0.3: 0.1-1.0; n5 is 0.1 to 1.0, x is 1 to 20, the sum of y and z is 5 to 200, A conductive paint composition comprising the repeating unit wherein the polyurethane resin is R ³ is an aromatic hydrocarbon and a repeating unit is an R ³ aliphatic hydrocarbon.      The composition of claim 1, wherein said composition is       a) 0.1-60 wt% of water dispersion polyurethane dispersion;       b) metal powder: 10-60 wt%; And       c) solvent: 10-60 wt%. d) Rheology control agent: Conductive paint composition comprising 0.1 to 20wt%. The conductive paint composition of claim 1, wherein the R ³ is a water-dispersed polyurethane disperse mixture using an aromatic hydrocarbon and an aliphatic hydrocarbon, and the content ratio of the aromatic hydrocarbon and the aliphatic hydrocarbon is in the range of 99: 1 to 1:99. .      The conductive paint composition of claim 1, wherein the aromatic hydrocarbon is selected from the group consisting of isophthalic acid, terephthalic acid, phthalic anhydride, and trimethyl anhydride.      The conductive paint composition according to claim 2, wherein the metal powder is a mixed powder of silver powder having an average particle size of 1-5 µm and silver powder having an average particle size of 4-10 µm.      The method of claim 2, wherein the solvent is selected from the group consisting of methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl acetate, methylpyrrolidone, acetone, methyl cellulsolve, ethyl cellulsolve, butyl cellulsolve Conductive paint composition.      3. The conductive paint composition of claim 2, wherein the rheology control agent is an acrylic polymer.      8. The conductive paint composition of claim 7, wherein the rheology control agent is paste. Method of manufacturing a conductive film for shielding electromagnetic waves comprising the following steps: (a) applying a conductive paint composition comprising a polyurethane disperse comprising a water dispersible polyurethane resin of Formula 1, a metal powder, a solvent, and a rheology control agent on a substrate;  [Formula 1]

Wherein R ¹ is an aliphatic hydrocarbon having 4 to 12 carbon atoms, a cyclic aliphatic hydrocarbon having 6 to 15 carbon atoms, or a mixture thereof; R ² is an aliphatic hydrocarbon having 2 to 12 carbon atoms; R ³ is an aliphatic hydrocarbon having 2 to 20 carbon atoms and an aromatic hydrocarbon having 6 to 20 carbon atoms; R ⁴ and R ⁵ are hydrogen or a methyl group; R ⁶ is an aliphatic hydrocarbon having 3 or 4 carbon atoms; R ⁷ is hydrogen or an aliphatic hydrocarbon having 1 to 9 carbon atoms; R ⁸ is an aliphatic hydrocarbon having 1 to 10 carbon atoms, a cyclic aliphatic hydrocarbon having 3 to 10 carbon atoms, or a mixture thereof; the ratio of n1: (n2 + n4 + n6): n3: n4 is 0.2-1.5: 1.0-3.0: 0.01-0.3: 0.1-1.0; n5 is 0.1 to 1.0, x is 1 to 20, the sum of y and z is 5 to 200, The polyurethane resin includes a repeating unit in which R ³ is an aromatic hydrocarbon and a repeating unit in which R ³ is an aliphatic hydrocarbon,        (b) heat-treating the coated substrate obtained in the previous step in a drying furnace. 10. The method of claim 9, wherein the drying step is performed at a temperature of 40 ℃ ~ 70 ℃. 10. The method of claim 9, wherein the substrate is polycarbonate, polycarbonate alloy, acryl butadiene styrene (ABS), acryl butadiene styrene / polycarbonate copolymer (ABS / PC), polyphenylene sulfite (PPS) resin Electromagnetic shielding conductive film production method characterized in that it is selected from the group consisting of. Electromagnetic shielding conductive film produced by the method of claim 9. Electromagnetic shielding substrate comprising an electroconductive shielding film prepared by the method of claim 9.