CN114250013A

CN114250013A - Sprayable conductive ink and conductive element

Info

Publication number: CN114250013A
Application number: CN202011000897.XA
Authority: CN
Inventors: 陈龙宾; 王雪芬; 朱俊鸿; 陈威州
Original assignee: TPK Touch Solutions Xiamen Inc
Current assignee: TPK Touch Solutions Xiamen Inc
Priority date: 2020-09-22
Filing date: 2020-09-22
Publication date: 2022-03-29
Also published as: KR20220039504A; JP2022051639A

Abstract

A conductive ink and a conductive element capable of spraying, wherein the conductive ink capable of spraying comprises 0.05 to 1 weight part of metal nanowires, 0.1 to 1 weight part of resin, 97.9 to 99.5 weight parts of solvent and 0.02 to 0.1 weight part of additive, wherein the conductive ink capable of spraying is used for spraying on a substrate. The conductive film formed by using the conductive ink capable of being sprayed disclosed by the invention has a smooth surface under strong light, and the formed conductive film has the advantages of uniform heating and high heating speed.

Description

Sprayable conductive ink and conductive element

Technical Field

The present disclosure relates to inks, and more particularly, to a sprayable conductive ink.

Background

With the development of technology, various ink coating methods, such as slot die coating (slot die coating), have been developed. The slot coating may be a roll to roll (roll) or a sheet to sheet (sheet). However, the conventional slit coating can only be applied to coating of a planar substrate, and is not easily applied to processing of a 3D curved substrate.

Another ink coating method is spray coating (spraying coating), which can solve the problem that the conventional slit coating is not easy to process a 3D curved substrate. However, when the ink is applied to the substrate by spraying and then baked to volatilize the solvent, the appearance of the ink layer is likely to be uneven or defective, such as bubbles (bubbles), pinholes (pinholes), cloudiness (cloudy mura), and stripes (pitch mura).

In view of the foregoing, there is a need to develop a new ink to overcome the above problems.

Disclosure of Invention

In order to solve the above problems and overcome the disadvantages of the prior art, the present disclosure provides a sprayable metal nanowire ink, in which a transparent metal conductive layer formed by the ink has good appearance and optical properties.

The present disclosure provides a conductive ink capable of being sprayed, which comprises 0.05 to 1 part by weight of metal nanowires, 0.1 to 1 part by weight of resin, 97.9 to 99.5 parts by weight of solvent, and 0.02 to 0.1 part by weight of additive, wherein the conductive ink is used for spraying on a substrate.

In some embodiments, the jettable conductive ink has a viscosity between 0.5cP and 50 cP.

In some embodiments, the jettable conductive ink has a surface tension between 10mN/m and 50 mN/m.

In some embodiments, the material of the metal nanowires is copper, gold, silver, nickel, iron, tin, or palladium.

In some embodiments, the resin is a polyvinyl butyral resin, ethyl cellulose, polyethylene, polystyrene, polytetrafluoroethylene, phenolic resin, polyamide resin, polypropylene, polycarbonate, hydroxypropyl methylcellulose, carboxymethyl cellulose, or silicone.

In some embodiments, the surfactant is selected from the group consisting of octylphenol ethoxylate, nonylphenol ethoxylate alkylphenol, fluorosurfactant, modified polysiloxane, polydimethylsiloxane, and silicone glycol copolymer.

In some embodiments, the additive comprises a surfactant, wetting dispersant, surface conditioner, or defoamer.

In some embodiments, the surfactant comprises 0.001 to 0.01 parts by weight.

In some embodiments, the wetting dispersant comprises 0.01 to 0.1 parts by weight.

In some embodiments, the surface modifying agent comprises 0.01 to 0.1 parts by weight.

In some embodiments, the defoamer comprises 0.02 to 0.1 parts by weight.

The present disclosure provides a conductive element comprising a substrate and an ink layer. The printing ink layer covers the substrate, wherein the printing ink layer is formed by spraying the conductive printing ink capable of spraying, the resistance value of the printing ink layer is 18-22 ohm/square, the penetration rate of the printing ink layer is larger than 90%, and the haze of the printing ink layer is smaller than 1.8%.

In some embodiments, the ink layer can be connected to an external power source to heat the conductive element.

In some embodiments, the power supply provides a predetermined energy density to cause the conductive element to rise greater than 20 ℃ within a predetermined time.

In some embodiments, the ink layer is a smooth surface in high light.

In some embodiments, the ratio of the resistances of the ink layers in two orthogonal directions is 0.97 ± 0.09.

In some embodiments, the substrate is a curved substrate.

The following detailed description is provided to explain the present disclosure by way of example and to provide further explanation of the present disclosure.

Drawings

The detailed description of the present disclosure will be best understood when read in conjunction with the appended drawings. It should be noted that, in accordance with standard practice in the industry, the various features are not drawn to scale and are used for illustrative purposes only. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

Fig. 1A-1D are experimental diagrams of metal conductive layers under a high-light lamp according to some comparative examples of the present disclosure;

FIG. 2 is a schematic diagram of a coater apparatus according to some embodiments of the present disclosure;

FIG. 3 is a schematic cross-sectional view of a conductive glass according to an embodiment of the disclosure;

fig. 4 is an experimental diagram of a metal conductive layer under a high-intensity lamp according to some embodiments of the present disclosure.

[ notation ] to show

10 spraying machine platform equipment

12: workbench

14 spray gun

16: nozzle

20: conductive glass

22 glass

24 ink layer

H spray height

Theta is the angle of the nozzle

Detailed Description

In the following description, for purposes of explanation, numerous implementation details are set forth in order to provide a thorough understanding of the various embodiments of the present invention. It should be understood, however, that these implementation details are not to be interpreted as limiting the invention. That is, in some embodiments of the invention, such implementation details are not necessary. In addition, for the sake of simplicity, some conventional structures and elements are shown in the drawings in a simple schematic manner.

In the description and claims, the articles "a" and "an" may refer broadly to one or more of the individual elements unless the context specifically states otherwise. As used herein, the term "about", "about" or "approximately" generally refers to a numerical error or range that is within about twenty percent, preferably within about ten percent, and more preferably within about five percent. In addition, in accordance with the present disclosure, the use of the term "parts by weight" is intended to mean the content of the chemical composition, for example, when the total parts by weight of the solution composition is 100 parts by weight, wherein the content of the composition A is 50 parts by weight, i.e., the concentration of A is 50 wt%.

Although the spraying coating can solve the problem that the 3D curved substrate is not easily processed by the conventional slit coating, the non-uniformity and the defects of the appearance of the ink layer are easily caused by coating the ink on the substrate in a spraying manner and then baking the ink to volatilize substances such as a solvent. Fig. 1A to 1D are experimental diagrams of metal conductive layers under a high-light lamp according to some comparative examples of the present disclosure. As shown in fig. 1A to 1D. Fig. 1A shows that the metal conductive layer under the powerful lamp has bubbles (bubbles), fig. 1B shows that the metal conductive layer has pinholes (pinholes), fig. 1C shows that the metal conductive layer has a cloudiness (cloudy mura), and fig. 1D shows that the metal conductive layer has a line shape (pitch mura). In addition, in order to make the conductive layer appearance of fig. 1A to 1D more clearly appear, accessories 1 to 4 are color diagrams of fig. 1A to 1D.

To address the above-mentioned problems, the present disclosure provides a sprayable conductive ink/paste. The ink of the present disclosure is atomized by spray coating (spray coating) to form uniform and fine droplets of the ink, and a wet ink layer is formed on the substrate. The wet ink layer is baked to form a dry ink layer, thereby forming a transparent and conductive thin film (or referred to as a transparent metal conductive layer) on the substrate. The spraying technology has the advantages of simple process, low equipment cost, capability of being coated on a non-flat substrate, capability of reducing the material consumption, automation, high efficiency, wide application material range and the like. The material to which the spray coating technique is applied may be various materials such as metal, alloy, or ceramic. The spray coating techniques of the present disclosure may include, but are not limited to, air spraying and electrostatic spraying. The conductive ink capable of being sprayed has good ink spraying performance and can be used for spraying various substrates, such as a plane substrate, a curved substrate and a substrate with a non-flat surface. And the problem that the curved substrate is difficult to process by slit coating in the prior art can be solved.

The substrate used in the present disclosure includes, but is not limited to, glass, wafer, quartz, polyethylene terephthalate (PET), Cyclic Olefin Polymer (COP), Cyclic Olefin Copolymer (COC), Polycarbonate (PC), polymethyl methacrylate (PMMA), Polyimide (PI), polyethylene naphthalate (PEN), polyvinylidene fluoride (PVDF), or polydimethylsiloxane (pdms). In one embodiment, the conductive ink of the present application is sprayed on a glass substrate, and then baked to form a dry ink layer, thereby forming transparent and conductive glass. In another embodiment, the glass coated with the conductive ink of the present disclosure can be applied to, for example, the glass of an automobile (such as a windshield or other glass), so that the conductive ink formed by spraying in this embodiment should have both optical characteristics (high light transmittance, low haze and good appearance) and appropriate heating characteristics. Generally, the resistance of the conductive ink formed by spraying in the present embodiment can be 18 to 22 ohm/square, the transmittance is greater than 90%, and the haze is less than 1.8%; and the heating characteristic is mainly applied to the defogging/defrosting functions of the automobile glass. That is to say, when the conductive ink glass in this embodiment is assembled in an automobile, the conductive ink glass itself has excellent optical characteristics, and a user cannot visually observe the conductive ink layer on the window, so that the problem of shielding the view of the conventional window with a metal electrode as a heating coil can be solved.

The conductive ink of the present disclosure includes mainly metal nanowires, a resin, a solvent, and a surfactant. In one embodiment, the surface tension of the jettable conductive ink is between 10mN/m and 50mN/m, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50 mN/m. In one embodiment, the surface tension of the jettable conductive ink is between 20mN/m and 30 mN/m. In another embodiment, the surface tension of the jettable conductive ink is between 25mN/m and 35 mN/m. It should be noted that the transparent conductive layer with better characteristics can be obtained by using the ink with a proper surface tension range. If the surface tension is too large or too small, the process and the spraying result will be affected, and the appearance of the transparent metal conductive layer will be affected. When the surface tension is less than 10mN/m, the ink may be excessively diffused, thereby affecting the spraying process. When the surface tension is greater than 50mN/m, it is not easy to effectively control the degree of spreading of the ink, thereby affecting the overall properties of the ink layer.

In one embodiment, the viscosity of the conductive ink is between 0.5cP and 50cP, for example, 0.5, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 cP. It should be noted that the ink with the viscosity in this range can obtain a transparent conductive layer with better characteristics, and if the viscosity is too high or too low, the process and the spraying result will be affected, and the appearance of the transparent metal conductive layer will be affected. When the viscosity is less than 0.5cP, the ink tends to be too dispersed, and the ink cannot be uniformly sprayed on the substrate. When the viscosity is more than 50cP, ink droplets are easily accumulated, thereby causing a problem of head clogging. Generally, the spraying process and other ink coating methods, such as slot die coating (slot die coating), are wet processes in which ink is directly coated on a substrate and cured, but considering the difference of equipment/parameters, the viscosity of the conductive ink of the embodiment is about 1/3-1/5 for the nano-metal wire ink applied in slot coating.

In one embodiment, the conductive ink for spraying of the present disclosure comprises 0.05 to 1 part by weight of metal nanowires, 0.1 to 1 part by weight of resin, 97.9 to 99.5 parts by weight of solvent, and 0.02 to 0.1 part by weight of additive. In one embodiment, the conductive ink is applied to a substrate.

In an embodiment, the metal nanowire may include copper, gold, silver, nickel, iron, tin, palladium, or an alloy thereof, but is not limited thereto. Specifically, the metal nanowires comprise gold nanowires, silver nanowires, nickel nanowires, iron nanowires, tin nanowires, palladium nanowires, or a combination thereof. As used herein, "metal nanowires (metal nanowires)" is a collective term referring to a collection of metal wires comprising a plurality of elemental metals, metal alloys or metal compounds (including metal oxides), wherein the number of metal nanowires contained therein does not affect the scope of protection claimed by the present invention; and at least one cross-sectional dimension (i.e., cross-sectional diameter) of the single metal nanowire is less than about 500nm, preferably less than about 100nm, and more preferably less than about 50 nm; while the metal nanostructures referred to herein as "wires" have a predominantly high aspect ratio, e.g., between about 10 and 100,000, more particularly, the metal nanowires may have an aspect ratio (length: diameter of cross-section) of greater than about 10, preferably greater than about 50, and more preferably greater than about 100; the metal nanowires can be any metal or alloy thereof, including, but not limited to, silver, gold, copper, nickel, and gold-plated silver. Other terms such as silk (silk), fiber (fiber), tube (tube), etc. having the same dimensions and high aspect ratio are also within the scope of the present application.

In one embodiment, the jettable conductive ink includes 0.05 to 1 part by weight of the metal nanowires. Within this range, the ink layer has both conductive and light-transmitting properties. When the nanowire component is less than 0.05 part by weight, the transparent metal conductive layer formed by the spraying process has poor conductivity, affecting the conductive property. When the nanowire component is greater than 1 part by weight, the transparent metal conductive layer formed by the spraying process has poor transmittance.

In an embodiment, the resin may comprise polyvinyl butyral resin, ethyl cellulose, polyethylene, polystyrene, polytetrafluoroethylene, phenolic resin, polyamide resin, polypropylene, polycarbonate, hydroxypropyl methylcellulose, carboxymethyl cellulose, silicone, or a combination thereof, but is not limited thereto. In one embodiment, the conductive ink comprises 0.1 to 1 part by weight of a resin. Within this content range, the resin can provide an appropriate viscosity. For example, when the resin component is less than 0.1 part by weight, the adhesion of the ink is small and the ink cannot be coagulated. When the resin component is more than 1 part by weight, the ink is too viscous to be smoothly sprayed, and a uniform ink layer cannot be obtained.

In one embodiment, the solvent may include water, methanol, ethanol, N-hexane, ethyl acetate, acetone, N-dimethylformamide, acetic acid, N-butanol, N-propanol, isopropanol, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoramide, 1, 3-dimethyl-2-imidazolidinone, rosin water, turpentine, methyl acetate, formic acid, or a combination thereof, but is not limited thereto. In one embodiment, the conductive ink comprises 97.9 to 99.5 parts by weight of a solvent. Within this range, the solvent in the ink can provide the ink with appropriate properties of fluidity, transferability, uniformity, and the like.

In one embodiment, the additive comprises a surfactant, wetting dispersant, surface conditioner, defoamer, or a combination thereof.

In one embodiment, the surfactant may comprise octylphenol ethoxylate, nonylphenol ethoxylate alkylphenol, fluorosurfactant (FS-3100), modified polysiloxane (SL-1), polydimethylsiloxane (SL-8), silicone glycol copolymer (SL-10W), or a combination thereof. In one embodiment, the conductive, jettable ink includes 0.02 to 0.1 parts by weight of a surfactant. Within this range, the ink is maintained at an appropriate surface tension, so that the dispersoid in the ink composition is maintained stable. For example, when the surfactant is less than 0.02 parts by weight, excessive aggregates or precipitates may be generated. When the surfactant is more than 0.1 part by weight, there may be no coagulation effect between the respective dispersoids. In one embodiment, the surfactant comprises a fluorosurfactant. The conductive ink comprises 0.001 to 0.01 parts by weight of a surfactant. In one embodiment, the wet ink layer after spraying comprises 0.0001 to 0.01 parts by weight of a surfactant. In one embodiment, the baked dry ink layer contains 0.01 to 0.1 parts by weight of a surfactant.

In one embodiment, the wetting and dispersing agent may comprise a phosphate ester compound (DP-1), a mixture of a polymeric carboxylic acid and a modified polysiloxane (DP-3SL), a polyacrylic ammonium salt (DP-6W), an anionic polyacrylic acid sodium salt (DP-2512W), an acid group-containing polymer (DP-2140), a polyurethane polymer (SDP), a modified acrylic polymer interpolymer (Disperbyk-2000), or a combination thereof. In one embodiment, the conductive jettable ink further comprises a wetting dispersant in an amount of 0.02 to 0.1 parts by weight. Within this range, it is ensured that the conductive ink that can be sprayed does not coagulate, settle, or clog the nozzle during spraying. For example, when the wetting dispersant is less than 0.02 parts by weight, coagulation and sedimentation of the ink may not be avoided. When the wetting dispersant is more than 0.1 part by weight, a phenomenon of a hang-up spray head may be caused during spraying. In one embodiment, the conductive, jettable ink may include 0.01 to 0.1 parts by weight of a wetting dispersant.

In one embodiment, the surface conditioner may comprise a polymethylalkylsiloxane solution (BYK-077), a polyether-modified polymethylalkylsiloxane solution (BYK-320), a polyether-modified polydimethylsiloxane (BYK-331), an epoxy-functional methoxysilane (A8), a phosphate complex (A10), or a combination thereof, but is not limited thereto. In one embodiment, the conductive ink capable of being sprayed further comprises 0.02 to 0.1 parts by weight of a surface conditioner. The surface conditioner can eliminate the problems of coarse and uneven surface, etc., thereby forming a fine and dense film. In one embodiment, the conductive ink capable of being sprayed further comprises 0.01 to 0.1 parts by weight of a surface conditioner.

In one embodiment, the anti-foaming agent can comprise silicone (BYK-023), mineral oil (BYK-034), hydrophobic particles (BYK-034), polyether siloxane copolymer (SDK-1), polyether siloxane copolymer (SDK-4AF), polydimethylsiloxane (SDK-4350), or a combination thereof. In one embodiment, the conductive ink for jettable further comprises an antifoaming agent in an amount of 0.02 to 0.1 parts by weight. Within this range, no foam is generated during the spraying process. For example, when the defoaming agent is less than 0.02 parts by weight, the ink generates foam due to the alkaline substances in the composition, thereby affecting the appearance of the transparent metal conductive layer. When the defoaming agent is more than 0.1 parts by weight, the viscosity and surface tension of the ink may be affected, thereby affecting the overall properties of the ink and the transparent metallic conductive layer. In view of the above, the ink composition of the present embodiment has its particularity in consideration of the heating effect of the transparent metal conductive layer formed by the spraying process after being electrified. In one embodiment, the conductive ink for spraying further comprises an antifoaming agent in an amount of 0.01 to 0.1 parts by weight.

The equipment of the spraying process comprises a pressure barrel, an electronic balance, a control panel, a high efficiency filter (HEPA), a spraying room, a workbench (stage), a spray gun, an exhaust pipe and spraying machine equipment.

Referring to fig. 2, fig. 2 is a schematic diagram of a coater apparatus according to some embodiments of the disclosure. The paint booth apparatus 10 includes a work table 12 and a spray gun 14. The spray gun 14 is fixed above the table 12, and the vertical distance between the table 12 and the spray gun 14 is the spray height H, as shown in fig. 2. The spray gun 14 has a nozzle 16, and the nozzle 16 includes a nozzle angle θ that regulates the angle at which ink is ejected. The coater unit 10 is configured to lift the thimble by air pressure, so that the ink flows into the nozzle 16, and then atomizes the ink by the atomizing pressure. And spraying the atomized ink on the substrate, wherein the ink can be uniformly dispersed on the surface of the substrate to form a wet ink layer. And then, baking the wet ink layer sprayed on the substrate. And volatilizing substances such as a solvent in the ink layer through the baking step, thereby obtaining the ink layer, namely the transparent metal conducting layer. The parameters of the spraying machine equipment comprise spraying speed, spraying height H, atomizing pressure, spraying times, spraying flow, nozzle angle theta, spraying interval (pitch), baking temperature and baking time.

In one embodiment, the spray velocity is from 100 to 1000 m/sec. In one embodiment, the spray height is 2 to 100 mm. In one embodiment, the atomization pressure is 0.5 to 5 psi. In one embodiment, the number of spraying is 1 to 10. In one embodiment, the spray flow rate is 0.1 to 10 g/mm. In one embodiment, the nozzle angle is 0 to 45 degrees. In one embodiment, the spray spacing is 0.5 to 10 mm. In one embodiment, the baking temperature is 50 to 200 ℃. In one embodiment, the baking time is 1 to 60 minutes.

The inks of the present disclosure were sprayed onto 370mm by 470mm by 1.8mm glass substrates and baked according to the spray booth equipment, the above operations and the example parameters of the finally attached tables one to three, thereby forming dry transparent metal conductive layers. Then, a protective layer (also called "protective layer", top coat, hardcoat, etc.) is sprayed on the transparent metal conductive layer to indicate the functions achieved by the protective layer, for example, polyacrylate, epoxy resin, polyurethane, polysilane, polysiloxane, poly (silicon-acrylic acid), etc. are used and baked. The finally obtained transparent metal conducting layer has high light transmittance, low haze and good appearance, and has no bad appearance such as bubbles, pinholes, cloud and line shapes and the like. When the resistance value of the transparent metal conductive layer is 18-22 omega-cm, the transmittance of the transparent metal conductive layer is more than 90%, and the haze is less than 1.8%. In table one, a plurality of spraying experiments were performed using the ink composition of formula one in table three, and as a result, the conductive film with the above characteristics could be obtained. Table three shows two sets of inks of different compositions and spray applied under the spray conditions of example 4 in table one and the characteristics of the resulting conductive film.

Referring to fig. 3, fig. 3 is a schematic cross-sectional view of a conductive glass according to an embodiment of the disclosure. A conductive glass 20 includes a glass 22 and an ink layer 24. Ink layer 24 covers glass 22, wherein ink layer 24 is formed by spraying a conductive ink according to the present disclosure. In an embodiment, the ink layer 24 may further include a protective layer, and since the metal nanowires in the ink layer 24 form a mesh structure, the material of the protective layer may penetrate into the gaps between the metal nanowires to form a matrix (matrix material), so that the conductive ink and the protective layer form a composite conductive layer after being cured.

Since the spraying technique of the present embodiment directly sprays the ink onto the substrate, the cured ink layer has a relatively high isotropy, in other words, the characteristics of the ink layer in all directions, such as resistance/transparency/haze, are similar. In terms of the characteristics of the electrical resistance,since the metal nanowires have a high aspect ratio, when slit coating is used, the shear force between the machine coating head and the substrate causes the metal nanowires to be mostly aligned along the machine direction (the substrate transport direction, i.e., MD direction), so the resistance along the machine direction is smaller than that along the other directions, while the cross-axis direction (i.e., TD direction) perpendicular to the machine direction has a relatively large resistance, that is, the nano-metal wire film formed by slit coating has a significant anisotropy, such as the resistance along the cross-axis direction (R direction), without other adjustments_TD) Resistance (R) to machine direction_MD) The ratio is greater than 2. The metal nanowires in the ink layer formed by spraying in the embodiment are basically randomly arranged, so that the properties in all directions are similar; and in order to interact with the aforementioned R_TD/R_MDComparing (because there is no TD, MD direction in the spraying process), the present embodiment measures the resistance of the sprayed ink layer in two directions (two orthogonal directions are selected), and the ratio of the two is 0.97 ± 0.09, which shows that the spraying of the present embodiment has high isotropy.

In summary, the present disclosure provides a conductive ink capable of being sprayed on a generally planar substrate, a substrate with an uneven surface, and a curved substrate surface, such as a curved glass, to form a transparent conductive glass having good appearance and chemical properties. The obtained transparent conductive glass is uniform and smooth in surface, and has the properties of high transmittance and low haze. Because the ink layer contains the metal nanowires, the formed transparent conductive glass has a surface which can conduct electricity. And because the obtained transparent conductive glass has good appearance without the problems of bubbles, pinholes and the like, the transparent conductive glass has the advantages of uniform heating and high heating speed. The sprayable conductive inks of the present disclosure can be applied to a variety of non-planar substrates, such as the windshield of an automobile.

Table two shows the heating rate experiments obtained after energizing the conductive film formed by the conductive ink of the present disclosure. In the present embodiment, the oil film layer having a resistance of 18.6 ohm/sq was formed at 0.34x0.47m²A glass substrate of a size to form a conductive element and connected to an external power supply, the power supply providing powerThe power density is determined such that the conductive element rises more than 20 ℃ within a predetermined time. As can be concluded from Table two, when the power supply supplies the predetermined energy density above 900 deg.C, the conductive element can raise the temperature of the element by more than 20 deg.C within 5 minutes (the heating rate is about 4 deg.C/min); when the power supply provides the preset energy density of about 700, the temperature of the conductive element can be increased by more than 20 ℃ within 10 minutes (according to the continuous energization experiment of the embodiment, the temperature is increased to 20 ℃ in about 7 minutes of heating, and the heating speed is about 3 ℃/minute); the conductive element can be heated to a temperature of greater than 20 c in about 15 minutes (heating rate of about 1.33 c/min) when the power source provides a predetermined energy density of about 500 c. As described above, the conductive film of the present embodiment can achieve the defogging/defrosting function of the vehicle window by the heating effect after being electrified. It should be noted that the heating rate is simply calculated as temperature versus time, and the actual heating curve may be linear or non-linear. In one embodiment, the sprayed sample may be selected from a plurality of positions (e.g. four points) to perform an electrical heating experiment, and as a result, it is found that the heating curves (curves of heating time versus film temperature) of the positions are almost completely overlapped under the same voltage supply, which indicates that the conductive film of this embodiment has good uniform heating performance. In this embodiment, the temperature difference between any two positions on the conductive film of this embodiment is 10% or less, 5% or less, 2% or less, 1% or less, and 0.5% or less under the same voltage supply.

In another embodiment, the heating effect of the conductive film of the present embodiment after being powered on can also be applied to a display, such as a vehicle-mounted display, and since the display may have problems such as delayed picture and incorrect color display at low temperature, the vehicle-mounted display may be temporarily disabled in cold countries/environments when the vehicle is started.

In one embodiment, since the sprayed ink layer of the present embodiment has high isotropy, the uniformity of temperature rise of the ink layer during heating is also quite excellent, and thus, the effect of uniformity is provided for the whole device (e.g., defogging of a window).

In one embodiment, the ink is composed of 0.05 to 1 part by weight of metal nanowires, 0.1 to 1 part by weight of resin, 97.9 to 99.5 parts by weight of solvent, and 0.02 to 0.1 part by weight of additives, and can be used in a spraying process with a spraying flow (g/mm) of 1 to 5, a spraying speed (m/sec) of 400 to 500, and an atomization pressure (psi) of 1 to 3, to form a conductive film with high light transmittance, low haze, and good appearance, as shown in FIG. 4, the ink layer of which has a smooth surface under strong light; and the formed conductive film has the advantages of uniform heating and high heating speed. In addition, in order to make the appearance of the conductive film of fig. 4 more clearly appear, the accessory 5 is a color image of fig. 4.

Although the present disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the present disclosure, and thus the scope of the present disclosure is to be determined by that of the appended claims and their equivalents.

Table parameters of an embodiment

Table two heating rate experiment

Energy density (Power density) ═ voltage x current)/(area)

Ink formula for table three

Claims

1. A sprayable conductive ink comprising:

a metal nanowire accounting for 0.05 to 1 weight part;

a resin, which accounts for 0.1 to 1 weight portion;

97.9 to 99.5 parts by weight of a solvent; and

0.02 to 0.1 parts by weight of an additive, wherein the conductive ink is used for spraying on a substrate.

2. The conductive jettable ink of claim 1, wherein the conductive jettable ink has a viscosity between about 0.5cP and about 50 cP.

3. The jettable conductive ink of claim 1, wherein the jettable conductive ink has a surface tension of between 10mN/m and 50 mN/m.

4. The sprayable conductive ink of claim 1, wherein the metal nanowires are formed from a material selected from the group consisting of copper, gold, silver, nickel, iron, tin, and palladium.

5. The sprayable electrically conductive ink of claim 1, wherein the resin is a polyvinyl butyral resin, ethyl cellulose, polyethylene, polystyrene, polytetrafluoroethylene, phenolic resin, polyamide resin, polypropylene, polycarbonate, hydroxypropyl methylcellulose, carboxymethyl cellulose, or silicone.

6. The conductive jettable ink of claim 1, wherein the surfactant is selected from the group consisting of octylphenol ethoxylate, nonylphenol ethoxylate alkylphenol, fluorosurfactants, modified polysiloxanes, polydimethylsiloxane, and silicone glycol copolymers.

7. The sprayable electrically conductive ink of claim 1, wherein the additive comprises a surfactant, a wetting dispersant, a surface modifier, an antifoaming agent, or combinations thereof.

8. The sprayable electrically conductive ink of claim 7, wherein the surfactant comprises from 0.001 to 0.01 parts by weight.

9. The sprayable electrically conductive ink of claim 7, wherein the wetting dispersant comprises from 0.01 to 0.1 parts by weight.

10. The sprayable electrically conductive ink of claim 7, wherein the surface modifier comprises from 0.01 to 0.1 parts by weight.

11. The conductive ink of claim 7, wherein the defoamer is present in an amount of 0.02 to 0.1 parts by weight.

12. A conductive element, comprising:

a substrate; and

an ink layer covering the substrate, wherein the ink layer is formed by spraying the sprayable conductive ink according to claim 1, the resistance of the ink layer is 18-22 ohm/square, the penetration rate of the ink layer is more than 90%, and the haze of the ink layer is less than 1.8%.

13. The conductive element of claim 12, wherein the ink layer is capable of being heated by an external power source.

14. The conductive element of claim 13 wherein the power supply provides a predetermined energy density (power density) to cause the conductive element to rise greater than 20 ℃ within a predetermined time.

15. The conductive element of claim 12, wherein the ink layer is a smooth surface in the presence of intense light.

16. The conductive element of claim 12, wherein the ink layer has a ratio of resistances of 0.97 ± 0.09 in two orthogonal directions.

17. The conductive element of claim 12, wherein the substrate is a curved substrate.