Metal paste composition comprising liquid metal, electrode comprising the same and manufacturing method of electrode comprising the same

Abstract

The present disclosure relates to a metal paste composition comprising a liquid metal, an electrode comprising the same, and a method for manufacturing an electrode comprising the same. An electrode comprising a metal paste composition according to one embodiment can maintain high electrical conductivity by having a low rate of resistance change even under three-dimensional thermopressure molding.

Description

Technology Field

[0001] The present disclosure relates to a metal paste composition comprising a liquid metal, an electrode comprising the same, and a method for manufacturing an electrode comprising the same. Background Technology

[0003] Driven by rapid technological evolution and shifts in the industrial paradigm of the automotive market, the future vehicle sector is growing rapidly. Furthermore, as the utilization of vehicle interior space increases, there is a rising consumer demand for comfortable use, similar to an office or living room. Consequently, the role of interior lighting is evolving from merely illuminating to providing a comfortable environment and mood.

[0004] In particular, the development of flexible circuit boards capable of implementing lighting even on curved surfaces indoors is emerging as very important. Currently used production methods for displays, lighting, and sensors include metal insert molding, mechanical assembly of a board with printed electronic circuits with a plastic housing, and fusion methods using heat or ultrasound.

[0005] However, regarding conventional silver flake-based electrode compositions, there are disadvantages such as electronic circuits easily becoming disconnected due to heat and mechanical stress applied during the thermoforming process and the performance of mounted electronic devices degrading due to cracks, and there is a need to solve these issues. The problem to be solved

[0007] One embodiment aims to provide a metal paste composition comprising metal particles, a liquid metal, and a thermosetting polysiloxane compound.

[0008] Another embodiment aims to provide an electrode comprising: a substrate; and a conductive pattern formed on the substrate using the metal paste composition.

[0009] Another embodiment aims to provide a method for manufacturing an electrode comprising the steps of: preparing a substrate; forming a conductive pattern on the substrate using the metal paste composition; and acid treatment. means of solving the problem

[0010] One embodiment provides a metal paste composition comprising metal particles, a liquid metal, and a thermosetting polysiloxane compound.

[0011] In one embodiment, the weight ratio of the metal particles and the liquid metal may be 10:1 to 50:1.

[0012] In one embodiment, the metal particles may include one or more selected from the group consisting of gold (Au), silver (Ag), copper (Cu), nickel (Ni), tin (Sn), and alloys of two or more of these.

[0013] In one embodiment, the liquid metal may comprise any two or more alloys selected from the group consisting of gallium (Ga), indium (In), and tin (Sn).

[0014] In one embodiment, the liquid metal may be an alloy metal that is in a liquid state at room temperature.

[0015] In one embodiment, the thermosetting polysiloxane compound may include polydimethylsiloxane (PDMS).

[0016] In one embodiment, in a conductive pattern formed from the metal paste composition, the liquid metal may connect the metal particles.

[0017] Another embodiment provides an electrode comprising a substrate; and a conductive pattern formed on the substrate using the metal paste composition.

[0018] In one embodiment, the substrate may be any one selected from the group consisting of a polyethylene terephthalate (PET) substrate, a polyethylene naphthalate (PEN) substrate, a polyimide (PI) substrate, a polycarbonate (PC) substrate, a polypropylene (PP) substrate, a triacetylcellulose (TAC) substrate, and a polyethersulfone (PES) substrate.

[0019] In one embodiment, the resistance of the electrode after molding can increase by 50% to 180% compared to before molding.

[0020] Another embodiment provides a method for manufacturing an electrode comprising the steps of: preparing a substrate; forming a conductive pattern on the substrate using the metal paste composition; and acid treatment.

[0021] In one embodiment, the step of preparing the substrate may include the step of UV-ozone treating the substrate surface.

[0022] In one embodiment, the step of forming the conductive pattern may include a step of heat-curing at a temperature of 100°C to 200°C.

[0023] In one embodiment, the acid treatment step may include acid treatment with an acid containing HCl. Effects of the invention

[0024] The present disclosure relates to a metal paste composition comprising a liquid metal, an electrode comprising the same, and a method for manufacturing an electrode comprising the same. A metal paste composition according to one embodiment comprises metal particles and a liquid metal, and when the metal paste composition is applied to form a conductive pattern, the liquid metal connects the metal particles, thereby enabling the effect of improved electrical conductivity. Accordingly, an electrode comprising a metal paste composition according to one embodiment can undergo free shape deformation without short circuits occurring in the electrode during three-dimensional hot-press molding, and can maintain high electrical conductivity by having a low rate of change in resistance even after hot-press molding. Brief explanation of the drawing

[0025] Figure 1 shows a metal paste composition prepared in an example. FIG. 2 shows the electrodes of the example and comparative example before hot-press molding. Figure 3 shows the electrodes of the example and comparative example being hot-press molded with a triangular prism mold with a deformation angle of 60°. Figure 4 shows the electrodes of the example and comparative example being hot-press molded with a triangular prism mold with a deformation angle of 80°. Specific details for implementing the invention

[0026] Since the embodiments described in this specification may be modified in various different forms, the technology according to one embodiment is not limited to the embodiments described below. Furthermore, throughout the specification, the terms "comprising," "including," "containing," "containing," or "having" any component do not exclude other components but may include additional components unless specifically stated otherwise, and do not exclude elements, materials, or processes not additionally listed.

[0027] The numerical ranges used herein include lower and upper limits and all values ​​within those ranges, increments logically derived from the form and width of the defined ranges, all of which are limited, and all possible combinations of upper and lower limits of numerical ranges limited in different forms. For example, if the content of the composition is limited to 10% to 80% or 20% to 50%, the numerical ranges of 10% to 50% or 50% to 80% should also be interpreted as being described herein. Unless otherwise specifically defined in this specification, values ​​outside the numerical range that may occur due to experimental error or rounding of values ​​are also included within the defined numerical ranges.

[0028] Unless otherwise specifically defined in this specification, “about” may be considered as a value within 30%, 25%, 20%, 15%, 10%, 5%, 3%, 2%, 1%, or 0.5% of the specified value.

[0029] Hereinafter, the present disclosure will be described in detail (with reference to the attached drawings). However, this is merely illustrative and the present disclosure is not limited to the specific embodiments described illustratively.

[0030] One embodiment provides a metal paste composition comprising metal particles, a liquid metal, and a thermosetting polysiloxane compound.

[0031] In one embodiment, the liquid metal refers to a metal in a liquid state and can be added as a means to further enhance the conductivity of the metal paste composition. Additionally, the liquid metal has high fluidity upon shape deformation, so even after undergoing hot-press molding following the formation of a conductive pattern, it can maintain high conductivity with a low rate of resistance change.

[0032] In one embodiment, the weight ratio of the metal particles and the liquid metal may be 10:1 to 50:1. Specifically, the weight ratio of the metal particles and the liquid metal may be 10:1 to 45:1, 12:1 to 40:1, or 13:1 to 38:1, but is not necessarily limited thereto.

[0033] If the weight ratio of the metal particles to the liquid metal deviates from 10:1 to 50:1, such as when the liquid metal is added in an excessively small amount or the metal particles are added in an excessively large amount, the electrode produced therefrom cannot maintain high electrical conductivity after shape deformation.

[0034] In one embodiment, the metal particles may comprise one or more selected from the group consisting of gold (Au), silver (Ag), copper (Cu), nickel (Ni), tin (Sn), and alloys of two or more of these. Specifically, the metal particles may be silver flakes, but are not necessarily limited thereto. Silver flakes may be added as silver fine particles to ensure the conductivity of the metal paste composition, but if an excessively large amount is added, the dispersibility of the metal paste may be reduced.

[0035] In one embodiment, the shape of the metal particles is not particularly limited and may be, for example, plate-shaped. Specifically, the shape of the plate surface may be polygonal, circular, elliptical, regular, or irregular.

[0036] In one embodiment, the liquid metal may comprise two or more alloys selected from the group consisting of gallium (Ga), indium (In), and tin (Sn). Since the liquid metal only needs to be able to further increase conductivity by connecting metal particles through acid treatment, there are no special limitations on its composition, but specifically, it may comprise a gallium-indium eutectic alloy (EGaIn).

[0037] In one embodiment, the liquid metal may be in the form of particles. Specifically, the liquid metal may be primary particles or secondary particles formed by the aggregation of primary particles, but is not necessarily limited thereto.

[0038] In one embodiment, the thermosetting polysiloxane compound may include polydimethylsiloxane (PDMS). As a means for forming a pattern, the thermosetting polysiloxane compound may be a polymeric organic compound having a main framework formed by siloxane bonds (Si-O-Si) composed of silicon (Si) and oxygen (O), which can be thermosetting by a thermosetting agent upon heating. Specifically, the thermosetting polysiloxane compound may be silicone rubber or silicone resin, and may be, for example, polysiloxane, polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, or poly(dimethylsiloxane-methylsiloxane), but is not necessarily limited thereto.

[0039] In one embodiment, in a conductive pattern formed from the metal paste composition, the liquid metal may connect the metal particles. After the conductive pattern is formed, the liquid metal may connect the metal particles through chemical sintering by subsequent acid treatment, thereby further increasing conductivity.

[0040] In one embodiment, the metal paste composition may further include a thermosetting agent and an organic solvent.

[0041] The above-mentioned thermosetting agent is a material that forms a thermosetting polysiloxane compound upon heating, and specifically may include a Pt-based catalyst or a siloxane curing agent, but is not necessarily limited thereto.

[0042] The above organic solvent is not particularly limited in composition, provided that it sufficiently dissolves the aforementioned components to satisfy the desired dispersibility and viscosity, but it may be, for example, ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, etc., or alcohols such as 1-butanol, 2-butanol, isobutanol, isopropanol, isopentanol, etc., either alone or in combination.

[0043] Another embodiment provides an electrode comprising: a substrate; and a conductive pattern formed on the substrate using the metal paste composition. In this case, regarding the metal paste composition, the details regarding the metal paste composition described above may be applied in the same way, and duplicate details are omitted below.

[0044] In one embodiment, the electrode may be a shape-deformable electrode. Deforming the shape of the electrode includes both two-dimensional and three-dimensional deformation, and specifically may mean a change in length, a change from a straight line to a curve, a change in the angle of deformation, etc., but is not necessarily limited thereto.

[0045] In one embodiment, the substrate may be any one selected from the group consisting of a polyethylene terephthalate (PET) substrate, a polyethylene naphthalate (PEN) substrate, a polyimide (PI) substrate, a polycarbonate (PC) substrate, a polypropylene (PP) substrate, a triacetylcellulose (TAC) substrate, and a polyethersulfone (PES) substrate, but is not necessarily limited thereto.

[0046] In one embodiment, the resistance of the electrode after molding may increase by 50% to 180% compared to before molding. Specifically, the increase rate of the electrode's resistance may be 55% to 170%, 60% to 165%, 65% to 150%, 70% to 120%, 75% to 110%, or 80% to 100%, but is not necessarily limited thereto.

[0047] Another embodiment provides a method for manufacturing an electrode comprising the steps of: preparing a substrate; forming a conductive pattern on the substrate using the metal paste composition; and acid treatment. In this case, regarding the substrate, metal paste composition, and electrode, the aforementioned details regarding the substrate, metal paste composition, and electrode may be applied in the same manner, and duplicate details are omitted below.

[0048] In one embodiment, the step of preparing the substrate may include the step of treating the substrate surface with UV-ozone. Through the UV-ozone treatment, the adhesion between the substrate and the conductive pattern formed on the substrate may be improved.

[0049] In one embodiment, the step of forming the conductive pattern may include a step of heat curing at a temperature of 100°C to 200°C. The curing temperature may be 110°C to 190°C, 120°C to 180°C, or 130°C to 170°C, but is not necessarily limited thereto.

[0050] In one embodiment, the acid treatment step may include acid treatment with an acid containing HCl, and specifically, acid treatment using the vapor of an aqueous HCl solution. Through the acid treatment step, the oxide film of the liquid metal is removed, and at the same time, chemical sintering by the acid treatment enables the liquid metal to connect the metal particles, thereby allowing high electrical conductivity to be maintained even after the shape is deformed.

[0052] In the following, embodiments are further described with reference to specific experimental examples. The embodiments and comparative examples included in the experimental examples are merely illustrative of one embodiment and do not limit the appended claims. It is obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope and spirit of the present disclosure, and that such variations and modifications fall within the scope of the appended claims.

[0054] <Example 1> Preparation of an electrode containing liquid metal EGaIn

[0055] Step 1: Preparation of Liquid Metal EGaIn Microparticles

[0056] Liquid metal EGaIn and ethanol were mixed in a 1:4 ratio, sonicated at room temperature for 5 minutes, and the mixture was centrifuged to obtain EGaIn particles. Subsequently, the solvent was changed to isopropyl alcohol (IPA), and the EGaIn particles obtained primarily through the above process were centrifuged two more times under the same conditions to finally obtain liquid metal EGaIn microparticles.

[0057] Step 2: Preparation of metal composite composition

[0058] 1.04 g of silver flakes and 0.33 g of polydimethylsiloxane (PDMS) were placed in a centrifugal mixing apparatus (ARE-310, THINKY) and stirred, after which 0.044 g of EGaIn microparticles obtained in Step 1 and dodecane (C 12 H 26 0.06 g was added and stirred again. Subsequently, 0.067 g of PDMS curing agent and 0.06 g of dodecane were added to the mixture in sequence and stirred with a centrifugal mixing device to finally obtain a metal composite material composition.

[0059] Step 3: Preparation of the electrode

[0060] A polycarbonate (PC) film was used as a substrate, and the surface of the substrate was UVO-treated to improve adhesion. Then, a 1 mm thick slide glass and a stencil mask having a desired pattern formed on it were placed on the substrate. Next, using a screen printing technique, the metal composite material composition prepared in Step 2 was applied onto the stencil mask, and then heat was applied in an oven at 160°C for 3 hours to form a pattern. Subsequently, the patterned electrode was placed in a petri dish along with 30% concentration hydrochloric acid (HCl), and hydrochloric acid vapor was generated to acid-treat the patterned electrode to remove the oxide film of the EGaIn particles; the acid treatment was performed for 10 minutes.

[0061] <Example 2> Preparation of an electrode containing liquid metal EGaIn

[0062] An electrode containing liquid metal EGaIn was prepared in the same manner as in Example 1, except that in step 2 of Example 1, 1.1 g of silver flakes and 0.08 g of EGaIn microparticles were added and stirred.

[0063] <Example 3> Preparation of an electrode containing liquid metal EGaIn

[0064] An electrode containing liquid metal EGaIn was prepared in the same manner as in Example 1, except that in step 2 of Example 1, 1.05 g of silver flakes and 0.03 g of EGaIn microparticles were added and stirred.

[0066] <Comparative Example 1> Preparation of an electrode not containing liquid metal EGaIn

[0067] Step 1: Preparation of a metal composite composition

[0068] 1.6 g of silver flakes and 0.33 g of polydimethylsiloxane (PDMS) were placed in a centrifugal mixing device (ARE-310, THINKY) and stirred, then 0.067 g of PDMS curing agent and 0.19 g of dodecane were added in sequence and stirred once more with the centrifugal mixing device to obtain a metal composite material composition that does not contain liquid metal microparticles.

[0069] Step 2: Preparation of the electrode

[0070] A polycarbonate (PC) film was used as a substrate, and the surface of the substrate was UVO-treated to improve the adhesion of the substrate. Then, a 1 mm thick slide glass and a stencil mask having a desired pattern formed thereon were placed on the substrate. The metal composite material composition prepared in Step 2 was applied over it to form a pattern using a screen printing technique, and then heat was applied in an oven at 160°C for 3 hours to produce an electrode that does not contain liquid metal EGaIn.

[0071] <Comparative Example 2> Preparation of an electrode containing liquid metal EGaIn microparticles

[0072] An electrode containing liquid metal EGaIn was prepared in the same manner as in Example 1, except that in Step 2 of Example 1, 1.17 g of silver flakes and 0.58 g of EGaIn microparticles were added and stirred.

[0074] <Experimental Example 1> Measurement of Resistance Change Before and After Electrode Hot-pressure Forming

[0075] After performing vacuum hot-pressure forming using a vacuum forming machine (Vaquform), the change in electrode resistance before and after hot-pressure forming was measured. The specific experimental method is as follows. The resistance of the electrode was measured in advance before three-dimensional forming. Subsequently, the electrodes of the examples and comparative examples were placed on triangular prism molds with deformation angles of 60° and 80°, and vacuum hot-pressure forming was performed at a temperature of 210°C for 1 minute to form electrodes with a three-dimensional structure. After shape deformation, + and - terminals were connected to both ends of the electrode, and the line resistance was measured using a Multimeter (Fluke 287). The results compared with the resistance value before forming are shown in Table 1 below.

[0076] Deformation angle (°) Examples / Comparative Examples Metal particle:liquid metal weight ratio Resistance (Ω) before forming Resistance (Ω) after molding Resistance increase rate (%) 60 Example 1 23:1 23 61 165 Example 2 14:1 21 55 161 Example 3 35:1 24 64 167 Comparative Example 1 - 52 189 263 Comparative Example 2 2:1 25 78 212 80 Example 1 23:1 23 43 87 Example 2 14:1 21 38 81 Example 3 35:1 24 46 92 Comparative Example 1 - 73 193 164 Comparative Example 2 2:1 25 64 156

[0077] Referring to Table 1, the electrodes of Examples 1 to 3 have a weight ratio of metal particles to liquid metal of 14:1 to 35:1, and the increase in resistance is not significant even after vacuum hot-press molding. In particular, in the case of Example 2, which was vacuum hot-press molded to have a deformation angle of 80°, the increase in resistance before and after molding is the lowest at 81%.

[0078] On the other hand, Comparative Example 1 is an electrode that does not contain liquid metal and shows the largest change in resistance after vacuum hot-press molding, and Comparative Example 2 is an electrode with a weight ratio of metal particles to liquid metal of 2:1 and has a larger increase rate in resistance before / after molding compared to Examples 1 to 3.

[0079] Therefore, in order to maintain high conductivity with a low resistance increase rate even after thermopressure forming, metal particles and liquid metal having a specific weight ratio must be realized, and it can be seen that if liquid metal is not included or the specific weight ratio is deviated from, the electrode cannot maintain high conductivity after thermopressure forming.

[0081] The above description is merely an example applying the principles of the present disclosure, and other configurations may be further included without departing from the scope of the present disclosure. Although one embodiment has been described in detail through examples and experimental examples, the scope of one embodiment is not limited to specific embodiments and should be interpreted according to the appended claims.

Claims

Claim 1 A metal paste composition comprising metal particles, liquid metal, and a thermosetting polysiloxane compound, wherein the weight ratio of the metal particles to the liquid metal is 10:1 to 50:

1. Claim 2 delete Claim 3 A metal paste composition according to claim 1, wherein the metal particles comprise one or more selected from the group consisting of gold (Au), silver (Ag), copper (Cu), nickel (Ni), tin (Sn), and alloys of two or more of these. Claim 4 A metal paste composition according to claim 1, wherein the liquid metal comprises two or more alloys selected from the group consisting of gallium (Ga), indium (In), and tin (Sn). Claim 5 A metal paste composition according to claim 1, wherein the liquid metal is an alloy metal in a liquid state at room temperature. Claim 6 A metal paste composition according to claim 1, wherein the thermosetting polysiloxane compound comprises polydimethylsiloxane (PDMS). Claim 7 A metal paste composition according to claim 1, wherein, in a conductive pattern formed from the metal paste composition, the liquid metal connects the metal particles. Claim 8 An electrode comprising a conductive pattern formed using a metal paste composition according to any one of claims 1 and 3 to 7. Claim 9 In claim 8, the electrode, wherein the resistance of the electrode after molding increases by 50% to 180% compared to before molding. Claim 10 A method for manufacturing an electrode comprising: a step of preparing a substrate; a step of forming a conductive pattern on the substrate using a metal paste composition according to any one of claims 1 and 3 to 7; and a step of acid treatment. Claim 11 A method for manufacturing an electrode according to claim 10, wherein the step of preparing the substrate includes the step of treating the substrate surface with UV-ozone. Claim 12 A method for manufacturing an electrode according to claim 10, wherein the step of forming the conductive pattern comprises a step of heat-curing at a temperature of 100 ℃ to 200 ℃. Claim 13 A method for manufacturing an electrode according to claim 10, wherein the acid treatment step comprises acid treatment with an acid containing HCl. Claim 14 A method for manufacturing an electrode according to claim 10, wherein the substrate is selected from the group consisting of a polyethylene terephthalate (PET) substrate, a polyethylene naphthalate (PEN) substrate, a polyimide (PI) substrate, a polycarbonate (PC) substrate, a polypropylene (PP) substrate, a triacetylcellulose (TAC) substrate, and a polyethersulfone (PES) substrate.

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