CN108666047B

CN108666047B - Transparent conductive film and preparation method thereof

Info

Publication number: CN108666047B
Application number: CN201710213729.0A
Authority: CN
Inventors: 刘滨; 刘子莲; 徐焕翔; 蔡颖颖; 唐雁煌; 张莹洁; 王有亮; 彭泽亚
Original assignee: China Electronic Product Reliability and Environmental Testing Research Institute
Current assignee: China Electronic Product Reliability and Environmental Testing Research Institute
Priority date: 2017-04-01
Filing date: 2017-04-01
Publication date: 2020-04-07
Anticipated expiration: 2037-04-01
Also published as: CN108666047A

Abstract

The invention relates to a transparent conductive film and a preparation method thereof, wherein the preparation method comprises the following steps: soaking and etching the metal mesh in an etching solution until the light transmittance and/or the square resistance reach a preset value, placing the metal mesh in alcohol, performing ultrasonic cleaning, and airing at room temperature to obtain a conductive layer; flatly paving the conducting layer on a substrate with a flat surface, coating UV (ultraviolet) light curing resin on the conducting layer and the substrate, and carrying out light curing reaction on the UV light curing resin under an ultraviolet lamp to obtain a transparent base layer; and removing the substrate, and compounding the transparent base layer and the conductive layer to obtain the transparent conductive film. The metal mesh etching process is simple, the etching process is controllable, the conductivity and the light transmittance of the conductive layer can be adjusted by controlling the etching degree of the metal mesh, and the conductivity and the light transmittance of the transparent conductive film are further adjusted and controlled.

Description

Transparent conductive film and preparation method thereof

Technical Field

The invention relates to the technical field of conductive materials, in particular to a transparent conductive film and a preparation method thereof.

Background

The transparent conductive film is widely used in the fields of touch liquid crystal panels, Organic Light Emitting Diodes (OLEDs), electromagnetic shielding, smart phone touch screens, electronic paper, solar cells, and the like. At present, ITO films and metal films are two common transparent conductive films. Transparent conductive films using non-metallic conductivity have also been developed, and touch panels made of carbon nanotubes are used in Fraunhofer IPA. Specifically, a mixed solution of conductive resin PEDOT-PSS and CNT is coated on a PET resin film, and then a conductive film is formed; taiwan amateur electronics also used CNTs as the conductive part of touch screens to obtain transparent conductive films; due to the discovery of graphene which is a material with good light transmission, flexibility and conductivity, a plurality of researchers aim at graphene, samsung electrons and the like to prepare a touch panel consisting of 4 layers of graphene with the size of 30in, the sheet resistance is 30 omega, and the light transmittance reaches 90%; however, the bottleneck of realizing the mass production of the graphene is not broken through, so that the current graphene can only be used in a very small area, and the current industrial application of the graphene is greatly limited.

The ITO film is a transparent conductive material such as an indium-tin oxide film (ITO) formed on the surface of a transparent glass or plastic substrate by vapor deposition or sputtering; however, ITO films also have some drawbacks: the transmittance is difficult to improve without a reflecting film, the sheet resistance is difficult to reduce while the transmittance is maintained, the risk of breakage exists during excessive bending, and the plasticity is poor, so that the film is difficult to adapt to occasions requiring large flexibility; in addition, indium element is very rare and is not suitable for continuous development.

The metal film is formed on the surface of a transparent glass or plastic substrate by a metal plating or evaporation method, and then is processed by photoetching to etch the metal layer into a fine metal grid. However, when a metal film is processed and prepared, most of the metal film needs to be removed, which causes the defects of much waste and high production cost.

In recent years, scientists have proposed a new method of forming a mesh-shaped metal wire directly on the surface of a transparent substrate at one time, which is to form an Ag silk ink by blending and emulsifying raw materials such as silver nanoparticles, an organic solvent, a surfactant and an aqueous solvent, and when the Ag silk ink is coated on the surface of a transparent substrate, a silver mesh structure of an arbitrary shape is automatically formed on the surface of the substrate due to the difference in polarity, surface energy and volatility of the solvent, and the Ag silk ink becomes a transparent conductive film after sintering. However, the process flow of the preparation process of the nano Ag wire is complex, the cost of silver metal is high, the amount of solution additives is large, and the stability of the coating process is not easy to control.

Disclosure of Invention

Therefore, a transparent conductive film preparation method which is simple in process, low in equipment requirement and low in cost is needed, and the conductivity and the light transmittance of the transparent conductive film prepared by the preparation method can be regulated and controlled, and the transparent conductive film can be prepared on a large scale.

A method for preparing a transparent conductive film comprises the following steps:

soaking and etching the metal mesh in an etching solution until the light transmittance and/or the square resistance reach a preset value, placing the metal mesh in alcohol, performing ultrasonic cleaning, and airing at room temperature to obtain a conducting layer;

flatly paving the conducting layer on a substrate with a flat surface, coating UV (ultraviolet) light curing resin on the conducting layer and the substrate, and carrying out light curing reaction on the UV light curing resin under an ultraviolet lamp of 365nm for 2-4 h to obtain a transparent base layer; and

and removing the substrate, and compounding the transparent base layer and the conductive layer to obtain the transparent conductive film.

In one embodiment, the metal mesh is a copper mesh, an iron mesh or an aluminum mesh.

In one embodiment, the mesh number of the metal mesh is 400-1000 mesh, and the thickness of the metal mesh is 20-80 μm.

In one embodiment, the etching liquid is an iron chloride solution, and the concentration of the iron chloride solution is 0.5-2 mol/L.

In one embodiment, the time for the soaking and etching is 3-8 hours.

In one embodiment, the predetermined value of the transmittance is 60% to 85%, and the predetermined value of the sheet resistance is 400 to 1000 Ω/□.

In one embodiment, the ultrasonic cleaning time is 3-10 min.

In one embodiment, the UV light-curable optically transparent resin is a UV light-curable acrylic resin or a light-curable epoxy resin.

In one embodiment, the UV light-curable optically transparent resin is coated to a thickness of 30 to 100 μm.

The transparent conductive film is prepared according to the preparation method of the transparent conductive film.

According to the preparation method of the transparent conductive film, the metal mesh etching process is simple, and a complex coating process is not needed between the conductive layer and the transparent base layer; the metal net is adopted for etching, so that waste caused by a method for preparing a metal film by photoetching a metal layer can be reduced. In addition, the metal mesh etching process is controllable, the conductivity and the light transmittance of the conductive layer are adjusted by controlling the metal mesh etching degree, and the conductivity and the light transmittance of the transparent conductive film can be further adjusted and controlled.

On the other hand, when the prepared raw material adopts metal, particularly copper, the cost of the raw material is greatly reduced compared with the raw material cost of the current mainstream nano silver linear transparent conductive film and ITO transparent conductive film because the copper source is rich.

Drawings

Fig. 1 is a flowchart of a method for manufacturing a transparent conductive film according to an embodiment;

FIG. 2 is a cross-sectional view of a transparent conductive film structure made in accordance with one embodiment;

fig. 3 is a top view of the transparent conductive film structure of fig. 2.

Detailed Description

In order to facilitate an understanding of the present invention, a more complete description of the present invention is provided below. The detailed description sets forth the preferred embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

As shown in fig. 1, a method for manufacturing a transparent conductive film according to an embodiment includes the following steps:

step S110, soaking and etching the metal mesh in an etching solution until the light transmittance and/or the square resistance reach a preset value, placing the metal mesh in alcohol, performing ultrasonic cleaning, and drying the metal mesh at room temperature to obtain a conductive layer; wherein, the etching liquid is correspondingly selected according to different metal nets; the mesh number of the metal mesh is 400-1000 meshes, the thickness of the metal mesh is 20-80 mu m, and preferably, the metal mesh is a copper mesh, an iron mesh or an aluminum mesh; the etching solution can be but is not limited to ferric chloride solution, and the concentration of the ferric chloride solution is 0.5-2 mol/L; the soaking and etching time is 3-8 h, the preset value of the light transmittance is 60-85%, and the preset value of the square resistance is 400-1000 omega/□; the ultrasonic cleaning time is 3-10 min;

step S120, paving the conducting layer on a substrate with a smooth surface, coating UV (ultraviolet) light curing resin on the conducting layer and the substrate, and carrying out light curing reaction on the UV light curing resin for 2-4 h under an ultraviolet lamp of 365nm to obtain a transparent base layer; wherein the UV light-cured resin is UV light-cured acrylic resin or light-cured epoxy resin, and the coating thickness of the UV light-cured resin is 30-100 mu m;

and step S130, the substrate is taken off, and the transparent base layer and the conductive layer are compounded to obtain the transparent conductive film.

With reference to fig. 2 and 3, a transparent conductive film is prepared according to the above-mentioned method for preparing a transparent conductive film; the transparent conductive film comprises a transparent base layer 10 and a conductive layer 20, wherein the conductive layer 20 is a mesh structure, and the transparent base layer 10 is located on one side of the conductive layer 20 and is filled in the mesh gaps of the conductive layer 20; preferably, the conductive layer is an etched copper mesh, and the transparent base layer is polymethyl methacrylate.

The following specific examples are intended to further illustrate the invention, but are not intended to limit the invention.

Example 1

1. Placing a 600-mesh 40-micron copper net in a ferric chloride solution with the concentration of 1.5mol/L for soaking and etching for 4h until the light transmittance of the copper net reaches 85% and the square resistance reaches 400 omega/□, taking out the copper net, soaking the copper net in alcohol, ultrasonically cleaning for 3min, and then airing at room temperature, thus finishing the manufacturing of the conductive layer 20;

2. spreading the etched copper mesh on a glass sheet with a smooth surface, coating a thin layer of UV light-cured acrylic resin with the thickness of 50-70 microns on the copper mesh, and carrying out light-curing reaction on the UV light-cured acrylic resin for 2-4 h under an ultraviolet lamp with the wavelength of 365nm to form a transparent base layer 10;

3. and (3) removing the glass, and obtaining the composite film of the transparent base layer 10 and the conductive layer 20, namely the transparent conductive film.

Example 2

1. Placing a 800-mesh 30-micrometer copper net in a ferric chloride solution with the concentration of 0.8mol/L for soaking and etching for 5h until the light transmittance of the copper net reaches 80% and the square resistance reaches 600 omega/□, taking out the copper net, soaking the copper net in alcohol, ultrasonically cleaning for 5min, and then airing at room temperature, thus finishing the manufacturing of the conductive layer 20;

2. spreading the etched copper mesh on a glass sheet with a smooth surface, coating a thin layer of UV light-cured acrylic resin with the thickness of 40-50 mu m on the copper mesh, and carrying out light-curing reaction on the UV light-cured acrylic resin for 2-4 h under an ultraviolet lamp with the wavelength of 365nm to form a transparent base layer 10;

Example 3

1. Placing a 400-mesh 80-micrometer copper net in a ferric chloride solution with the concentration of 2mol/L for soaking and etching for 7h until the light transmittance of the copper net reaches 70% and the sheet resistance reaches 900 omega/□, taking out the copper net, soaking the copper net in alcohol, ultrasonically cleaning for 6min, and then drying at room temperature, thus finishing the manufacture of the conductive layer 20;

2. spreading the etched copper mesh on a glass sheet with a smooth surface, coating a thin layer of UV light-cured acrylic resin with the thickness of 30-50 microns on the copper mesh, and carrying out light-curing reaction on the UV light-cured acrylic resin for 2-4 h under an ultraviolet lamp with the wavelength of 365nm to form a transparent base layer 10;

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A method for preparing a transparent conductive film is characterized by comprising the following steps:

2. The method for producing a transparent conductive film according to claim 1, wherein the metal mesh is a copper mesh, an iron mesh, or an aluminum mesh.

3. The method for producing a transparent conductive film according to claim 1 or 2, wherein the mesh number of the metal mesh is 400 to 1000 mesh, and the thickness of the metal mesh is 20 to 80 μm.

4. The method according to claim 1, wherein the etching solution is an iron chloride solution, and the concentration of the iron chloride solution is 0.5 to 2 mol/L.

5. The method for preparing a transparent conductive film according to claim 1, wherein the time for the immersion etching is 3 to 8 hours.

6. The method according to claim 1, wherein the predetermined value of the transmittance is 60% to 85%, and the predetermined value of the sheet resistance is 400 to 1000 Ω/□.

7. The method for preparing a transparent conductive film according to claim 1, wherein the time for the ultrasonic cleaning is 3 to 10 min.

8. The method of manufacturing a transparent conductive film according to claim 1, wherein the UV light-curable optically transparent resin is a UV light-curable acrylic resin or a light-curable epoxy resin.

9. The method of manufacturing a transparent conductive film according to claim 1, wherein the UV light-curable optically transparent resin is applied to a thickness of 30 to 100 μm.

10. A transparent conductive film produced by the method for producing a transparent conductive film according to any one of claims 1 to 9.