KR102338522B1 - Transparent planar heating device and preparation method thereof - Google Patents

Abstract

In the present specification, a transparent planar heating element having excellent thermal conductivity and durability, including a silver (Ag) nanowire and a polymer-carbon composite, and a manufacturing method thereof are disclosed.

Description

Transparent planar heating element and manufacturing method thereof

The present specification relates to a transparent planar heating element having excellent thermal conductivity and durability and a method for manufacturing the same.

Silver nanowire (AgNW) transparent planar heating element is being applied to various fields such as construction, vehicle, sportswear, etc. with its advantages of high transparency and conductivity. In particular, when exposed to a low temperature environment, high thermal conductivity and high reliability under voltage are required.

However, if the heating element generates a high voltage to generate heat in a low temperature environment, and this causes local heat that is not evenly distributed, the durability of the product is reduced and frequent replacement is required.

In particular, in the development trend of silver nanowires (AgNW), in order to realize high conductivity, there is a trend to reduce the diameter when synthesizing silver nanowires (AgNW), which greatly affects durability as a heating element.

Therefore, it is necessary to develop a transparent planar heating element having excellent heat distribution uniformity and improved durability due to a reduction in the diameter of AgNW.

KR 10-2015-014829 A KR 10-1826149 B1

An object of the present specification is to provide a transparent planar heating element having excellent durability and a method for manufacturing the same, while including silver nanowires having a sufficiently small diameter for high thermal conductivity.

In exemplary embodiments of the present invention, a substrate; a heating layer located on the substrate; and an electrode positioned on the heating layer; Including, wherein the heating layer provides a transparent planar heating element comprising a silver (Ag) nanowire and a polymer-carbon composite.

In another exemplary embodiment of the present invention, as the above-described transparent planar heating element manufacturing method, applying a binder solution containing silver (Ag) nanowires on a substrate to form a silver (Ag) nanowire structure ; forming a heating layer by applying a binder solution containing a polymer and carbon on the silver (Ag) nanowire structure; and forming an electrode on the heating layer; it provides a transparent planar heating element manufacturing method comprising.

The transparent planar heating element of the present specification includes silver nanowires having a sufficiently small diameter for high thermal conductivity, and has excellent durability including a polymer-carbon composite.

1 is a schematic diagram of a transparent planar heating element according to an embodiment of the present invention.
2a is a schematic diagram of a transparent planar heating element including only silver nanowires on a substrate, and FIG. 2b is a schematic diagram of a transparent planar heating element according to an embodiment of the present invention including silver nanowires and a polymer-carbon composite on the substrate. .
3a is a schematic diagram showing thermal conductivity in a transparent planar heating element to which a conventional protective coating layer (including only polymers) is applied, and FIG. 3b is a schematic diagram showing thermal conductivity in a transparent planar heating element according to an embodiment of the present invention.
4a is a photograph showing the local heating of a transparent planar heating element to which a conventional protective coating layer (including only polymers) is applied, and FIG. 4b is a photograph of the transparent planar heating element prepared in Example 1 of the present specification.

In the present specification, when a part "includes" a certain component, this means that other components may be further included rather than excluding other components unless otherwise stated.

As used herein, the "three-dimensional network" structure refers to a three-dimensional network structure such as a net and a net entangled.

Hereinafter, exemplary implementations of the present specification are described in detail.

In exemplary implementations herein, the substrate 100; a heating layer 200 positioned on the substrate; and an electrode 300 positioned on the heating layer; Including, the heating layer provides a transparent planar heating element comprising a silver (Ag) nanowire 210 and a polymer-carbon composite 220.

In the case of a planar heating element including silver nanowires (AgNW), the protective coating layer (over-coat layer) can be used for the purpose of protecting the exposed portion by applying a polymer to cover a portion of the exposed AgNW. However, since the conventional overcoating layer made of only polymer has little connection between the electrode and the heating element when the electrode is formed, it is difficult to distribute an even voltage, and it does not help to dissipate heat when the nanowire generates heat. Heat is agglomerated and there is a risk of damage due to heat.

In contrast, in the present specification, a carbon material with high thermal conductivity such as graphene, CNT, and preferably nano-sized carbon is applied to the heating layer as a coating layer together with a polymer, so that the loss of current is small and the application of a uniform voltage is Since it is possible, the heat conduction efficiency is increased, so that the characteristics of the heating element that increases the ambient temperature can be improved.

In addition, since the carbon material plays a role in dispersing the heat generated by the current flowing through the silver nanowire, it is possible to prevent defects (the phenomenon of heat condensing and breaking in the thin-thick nanowire) that may be caused by heat accumulation in the silver nanowire. It can be prevented.

Specifically, referring to FIGS. 1 and 2B , the transparent planar heating element disclosed herein includes a silver (Ag) nanowire 210 in the heating layer 200 and a current flows by a voltage applied through the electrode, Real heat is generated. In addition, while the polymer-carbon composite 220 on the heating layer 200 serves as a coating layer of the silver nanowire, the durability that is deteriorated as the diameter of the silver nanowire is nano-unit is improved, and heat transfer efficiency to improve

In addition, referring to FIGS. 3a and 3b, the conventional transparent planar heating element does not contain a carbon material, so it is difficult to spread the heat generated by it ( FIG. 3a ), whereas the transparent planar heating element disclosed herein includes a carbon material with high thermal conductivity As a result (in FIG. 3B, the portion roughened compared to FIG. 3A), uniform diffusion and distribution of heat is possible (3b).

In addition, in the transparent planar heating element disclosed in the present specification, as shown in FIG. 1, the electrode is positioned on the top of the heating layer, a connection is created between the silver nanowire and the polymer-carbon in the carbon composite, and a voltage is applied through the polymer, which is an insulating material. A structure to be connected to the electrode part is formed. Due to this, the number of connections connected to the electrode part increases, and thus, it is possible to uniformly apply a voltage. In addition, due to this, when the transparent planar heating element is driven, it is possible to reduce the probability that the electrode can be concentrated in a local area to enable stable driving.

In an exemplary embodiment, the silver (Ag) nanowires may be connected in a three-dimensional network structure. Referring to FIGS. 2A and 2B , the silver (Ag) nanowire is a silver (Ag) nanowire structure like a metal mesh network connected as a whole, and the polymer-carbon composite is coated on the three-dimensional network structure, or the gap is filled. One heating layer 200 is formed.

In other words, referring to the manufacturing method to be described later, first, a silver (Ag) nanowire structure is formed on a substrate, and then a binder solution containing a polymer and carbon is applied to form a heating layer, so that the polymer-carbon composite The silver (Ag) nanowire structure may have the same shape as that in which it is immersed. Therefore, in particular, referring to the rough part compared to FIG. 3A in FIG. 3B , as a result, carbon is formed as if entangled between the silver nanowire, which is formed first, and the polymer, which is an insulator, so that when the electrode is formed on the heating element, the electrode The flow of current according to the voltage application between the heating element and the heating element can be maintained evenly.

In an exemplary embodiment, a part of the silver (Ag) nanowire may exist inside the polymer-carbon composite, and a part may exist outside the polymer-carbon composite.

In an exemplary embodiment, the silver (Ag) nanowire may have a diameter of 10 to 50 nm, for example, 10 nm or more, 40 nm or less, 30 nm or less, or 25 nm or less. If the diameter is less than 10 nm, the physical strength may be weak, which may cause durability or reliability problems, and if the diameter is more than 50 nm, thermal conductivity may be lowered.

In an exemplary embodiment, the length of the silver (Ag) nanowire may be 10 to 40 μm, for example, 15 to 25 μm. When the length is less than 10 μm, the silver (Ag) nanowires are not well connected to each other and thus function as a heating layer may be difficult. Although it has the effect of improving the physical properties (reduction of sheet resistance) of the electrode by forming a nanowire, it is difficult to synthesize the corresponding nanowire because it cannot be grown only in the longitudinal direction during the synthesis process, and the diameter is also grown together.

In an exemplary embodiment, the polymer-carbon composite is one or more polymers selected from the group consisting of polymethyl methacrylate, urethane and acrylic, and carbon fiber, graphite, single-walled or multi-walled carbon. It may include at least one carbon selected from the group consisting of nanotubes (Carbon Nano Tube), and graphene (Graphene).

The polymer may preferably be polymethyl methacrylate, but is not limited thereto as long as it is a polymer having transparency, and the carbon may be a single-walled carbon nanotube.

In an exemplary embodiment, the substrate may include at least one selected from the group consisting of a silicone substrate, a glass substrate, and a polymer substrate, and is not limited thereto, as long as it is a substrate capable of implementing the above-described transparent planar heating element.

In an exemplary embodiment, the electrode may include a single metal or alloy selected from the group consisting of aluminum, silver, gold, iron, platinum, and copper, but is not limited thereto as long as it has conductivity.

In an exemplary embodiment, the transparent planar heating element may be for a window, for a plastic house, for a mirror, for an automobile electric field, for sportswear heating goggles or for a heating glass, preferably for sportswear heating goggles or a transparent heating glass can be for

In exemplary embodiments of the present specification, as the above-described transparent planar heating element manufacturing method, applying a binder solution containing silver (Ag) nanowires on a substrate to form a silver (Ag) nanowire structure; forming a heating layer by applying a binder solution containing a polymer and carbon on the silver (Ag) nanowire structure; and forming an electrode on the heating layer; it provides a transparent planar heating element manufacturing method comprising.

Specifically, the step of forming the silver (Ag) nanowire structure may be performed by slot die coating, micro gravure coating, spin coating, spray coating, etc., which is not limited thereto, as long as it is an application technique capable of forming a moisture film . Thereafter, the steps of applying heat to the nanowire structure to blow off the solvent of the moisture film, and drying it to form a film may be additionally performed.

Thereafter, a binder solution containing a polymer and carbon may be applied on the silver (Ag) nanowire structure to form a heating layer, and after coating in the same manner as in the silver nanowire structure, additional heat treatment and drying are performed can be performed. The binder solution containing the polymer and carbon may be prepared by mixing a solution containing a polymer and a solution containing carbon, respectively.

After that, an electrode can be formed by printing a conductive paste (silver paste applied) on the heating layer and drying (sintering), drop casting, spin coating, electron beam deposition, thermal deposition, vacuum deposition, printing, slot die coating, It may be carried out by dip coating and microgravure coating.

In an exemplary embodiment, the binder solution including the silver (Ag) nanowires may further include distilled water, isopropyl alcohol (IPA), or ethanol (EtOH) as a solvent, and a methylcellulose-based binder as a binder.

In an exemplary embodiment, the binder solution containing the polymer and carbon is isopropyl alcohol (IPA), ethanol (EtOH), methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), propylene glycol methyl ether acetate ( PGMEA) may be further included.

Hereinafter, specific embodiments according to exemplary embodiments of the present invention will be described in more detail. However, the present invention is not limited to the following examples, and various types of embodiments can be embodied within the scope of the appended claims, and only the following examples are provided to ensure that the disclosure of the present invention is complete and are common in the art. It will be understood that the intention is to facilitate practice of the invention to those skilled in the art.

Example

Manufacture of transparent planar heating element

Example

After slot die coating using an aqueous solution containing AgNW (C3Nano, SNBA, diameter 25 nm or less, length about 20 μm) and a methylcellulose-based binder, hot air drying was performed to form a silver nanowire layer (structure). After that, a binder solution containing nano-sized single-walled carbon nanotubes and a PMMA-based polymer was coated on the silver nanowire layer (a herbicide) and dried with hot air to form an exothermic layer. Then, a conductive paste (silver paste applied) was printed on the heating layer, and dried (sintered) to form an electrode.

comparative example

In the above example, a transparent planar heating element was prepared in the same manner, except that a PMMA-based polymer binder solution not containing a carbon material (carbon nanotube) was used.

Experimental example

Fever evaluation

A voltage of 12.5V was applied to the heating element, and it was checked through a thermal imaging camera whether the heat was uniformly generated even after 3 hours had elapsed.

Referring to Figures 4a and 4b, it can be seen that in the case of Figure 4a showing the heating region of the planar heating element of the comparative example, the heating appears locally, whereas in the case of the transparent planar heating element of the embodiment, it can be confirmed that the heat is uniformly overall.

100: description
200: heating layer
210: silver (Ag) nanowire
220: polymer-carbon composite
300: electrode

Claims (10)

write; a heating layer located on the substrate; and an electrode positioned on the heating layer;
The heating layer includes a silver (Ag) nanowire and a polymer-carbon composite,
The polymer-carbon composite includes polymethyl methacrylate and single-walled carbon nanotubes (Carbon Nano Tube),
The heating layer is formed by coating a binder solution containing the silver (Ag) nanowire on the substrate to form a silver (Ag) nanowire structure, and then a polymer and carbon on the silver (Ag) nanowire structure It is created by applying a binder solution containing
The silver (Ag) nanowire structure is immersed in the polymer-carbon composite, a transparent planar heating element. According to claim 1,
The silver (Ag) nanowires are connected in a three-dimensional network structure, a transparent planar heating element. According to claim 1,
A portion of the silver (Ag) nanowire is present inside the polymer-carbon composite, and a part is present outside the polymer-carbon composite, a transparent planar heating element. According to claim 1,
The silver (Ag) nanowire has a diameter of 10 to 50 nm, a transparent planar heating element. According to claim 1,
The length of the silver (Ag) nanowire is 10 to 40 μm, a transparent planar heating element. delete According to claim 1,
The substrate is a silicone substrate, a glass substrate, and a transparent planar heating element comprising at least one selected from the group consisting of a polymer substrate. According to claim 1,
The electrode is a transparent planar heating element comprising a single metal or alloy selected from the group consisting of aluminum, silver, gold, iron, platinum, and copper. The method of claim 1,
The transparent planar heating element is for a window, for a plastic house, for a mirror, for an automobile electric field, for sportswear heating goggles or for a transparent heating glass, a transparent planar heating element. As a method for manufacturing a transparent planar heating element according to any one of claims 1 to 5 and 7 to 9,
forming a silver (Ag) nanowire structure by applying a binder solution including silver (Ag) nanowires on a substrate;
forming a heating layer by applying a binder solution containing a polymer and carbon on the silver (Ag) nanowire structure; and
Including; forming an electrode on the heating layer;
The polymer is polymethyl methacrylate, and the carbon is a single-walled carbon nano tube (Carbon Nano Tube), a transparent planar heating element manufacturing method.

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