KR100550940B1 - Electroconductive film coating composition for high transmission and emi shielding, and the coating film formed using the same - Google Patents

Abstract

The present invention relates to a high-permeability conductive film coating liquid composition for a flat panel display and a high-permeability conductive coating film prepared by using the same, and more specifically, (a) polyethylenedioxythiophene (PEDT) doped with polystyrene sulfonate (PSS); (b) silane coupling agents; (c) ether solvents; And (d) a highly permeable conductive film coating liquid composition comprising an alcohol solvent having 1 to 7 carbon atoms. Since the coating liquid composition of the present invention has excellent conductivity and high permeability, it is useful for large-sized film coating while eliminating screen drops due to electromagnetic waves in LCD-TV.

     Conductive, High Permeability, Film Coating Liquid, Flat Panel Display, LCD, PDP, CRT, EMI

Description

High Permeability Conductive Film Coating Liquid Composition for Flat Panel Display and High Permeability Conductive Coating Film Prepared Using Them {ELECTROCONDUCTIVE FILM COATING COMPOSITION FOR HIGH TRANSMISSION AND EMI SHIELDING, AND THE COATING FILM FORMED USING THE SAME}             

1 is a structural cross-sectional view of a direct backlight for an LCD-TV according to the prior art,

2 is a cross-sectional view of a direct backlight structure for an LCD-TV according to the present invention.

The present invention relates to a high-permeability conductive film coating liquid composition for a flat panel display and a high-permeability conductive coating film prepared using the same, and more particularly, to electromagnetic waves in an LCD-TV without degrading optical characteristics such as brightness and color of the LCD-TV. The present invention relates to a coating liquid composition using a conductive polymer capable of removing a screen failure due to an influence and at the same time making a large-size film coating possible.

Due to the rapid development of the electronics industry and the demands of the information materials and display industries, the damage caused by electromagnetic noise or electromagnetic interference (EMI) has become a serious problem. It is becoming more and more gradually.

Display devices such as LCDs, PDP cathode ray tubes (ELT), and ELs generate numerous radiations when they are driven, and a large part of these electromagnetic radiations are known to have a harmful effect on the human body when accumulated for a long time, as well as to their own driving circuits. This causes problems that destabilize signal processing. Especially for large-sized (26 inches or larger) LCD-TVs, a Cold Cathode Fluorescent Lamp (CCFL type) is used as a light source, and a diffuser plate, a conductive film, a diffusion film, and DBEF ( Dual Brightness Enhancement Film), which has a weak point that a defect (screen defect, waterfall) occurs on the exterior of the front panel due to electromagnetic waves generated from the light emitting driver. In the related art, in order to solve such a problem, when it is supplemented in a driving circuit, an apparatus cost and a panel manufacturing cost increase. Another method has been solved by forming a transparent conductive film on the surface of the glass substrate of display devices, mainly by ion sputtering or vacuum deposition using powder indium tin oxide (ITO) precursor. Used.

However, the sputtering method and the vacuum deposition method are limited in the capacity of the chamber chamber and the substrate size, so that the cost of applying a large display element of 1000mm ² or more is expensive, there is a big problem in terms of cost and mass production. Therefore, there is a need for a conductive coating solution for film to cope with large-scale glass panels while maintaining optical properties such as transparency.

The present invention is to solve the problems of the prior art as described above, while removing the screen failure (fallfall) due to the electromagnetic wave effect in the LCD-TV without degrading the optical characteristics such as brightness and color of the LCD-TV and at the same time larger An object of the present invention is to provide a coating liquid composition using a conductive polymer capable of film coating.

That is, one aspect of the present invention is (a) polyethylenedioxythiophene (PEDT) doped with polystyrenesulfonate (PSS); (b) silane coupling agents; (c) ether solvents; And (d) a highly permeable conductive film coating liquid composition comprising an alcohol solvent having 1 to 7 carbon atoms.

Another aspect of the present invention comprises the steps of: i) microgravure coating of the high permeability conductive film coating solution composition on PET film; And ii) to a method for producing a high permeable conductive film comprising the step of thermally firing the coating layer at 120 ~ 150 ℃ for 3 to 5 minutes.

Another aspect of the present invention relates to a highly transmissive conductive film having a characteristic of having a surface resistance of 10 ³ to 10 ⁴ Ω / □, a transmittance of 89% to 90%, and a hardness of 1H to 2H prepared by the above method, and a backlight including the same. .

The present invention will be described in more detail below.

In the present invention, water-soluble polyethylenedioxythiophene (PEDT), which is a kind of polythiophene-based polymer, is used as the conductive polymer. More preferably, PEDTs having a molecular weight in the range of 150,000 to 200,000 and doped with polystyrenesulfonate (PSS) as a dopant are used, and these PEDTs exhibit water-soluble properties and exhibit heat resistance, moisture resistance and UV stability. This has the advantage of being very good (hereinafter, PEDT means PEDT doped with PSS). In preparing the coating solution of the present invention, the PEDT is added in the form of an aqueous solution, wherein the aqueous solution of the PEDT is adjusted to 1.2 to 1.5% by weight of solids so as to maintain an optimum solubility in water. Since these PEDT aqueous solutions mix well with solvents having a high dielectric constant such as water and / or alcohol, they can be easily diluted and coated with these solvents.

The content of the aqueous PEDT solution (solid content of 1.2 to 1.5% by weight) in the coating liquid composition of the present invention is 20 to 30% by weight. The PEDT solution to less than 20% by weight if is more than the commercially available minimum of conductivity values of the surface resistance 10 ⁴ Ω / □, and a problem, use more than 30% by weight of the conductive thin film, the conductivity of the solid However, the thickness of the coating film is increased to decrease the optical characteristics such as brightness and color.

The silane coupling agent is added to the coating liquid composition of the present invention as a binder for improving the adhesion and the film hardness with the PET base film. As a specific example of the silane coupling agent used in the present invention, vinyltrimethoxysilane, vinyltriethoxysilane, gamma chloropropyltrimethoxysilane, enbetaaminoethylgammaaminopropyl Trimethoxysilane (N-β- (aminoethly) -γ-aminopropyltrimethoxysilane), gamma glycidoxypropyltrimethoxysilane, gamma-mecaptopropyltrimethoxysilane, samglyci 3-glycidoxypropyltrimethoxysilane and the like. When the coating solution composition of the present invention is prepared, they are reacted with water or additionally added water in the aqueous solution of PEDT to undergo hydrolysis and condensation reactions, followed by silica sol (-SiO ₂ -SiO _2- ) or alkylsilazole (R- After forming SiO ₂ -SiO _2- ), an organic-inorganic hybrid with PEDT is formed. Such silica sol forms a polysilicate crystal when the coating liquid composition including the same is coated on a PET film and then thermally cured. The polysilicate crystal has an adhesive property with a PET base film, and serves to increase the film hardness of the coating film. Done.

The content of the silane coupling agent in the coating solution composition of the present invention is 0.1 to 0.3% by weight. When the content is less than 0.1% by weight, sufficient film hardness (1H or more) cannot be achieved, whereas when the content is more than 0.3% by weight, the film hardness increases, but the amount of polysilicate that adversely affects the conductivity becomes excessive. Even with the addition of a separate conductivity enhancer, it is not possible to achieve a surface resistance of 10 ⁴ Ω / □ or less, which is a target of the electromagnetic shielding level of the present invention.

In the present invention, at least one C _1-7 alcohol solvent and an ether solvent may be used as a solvent for dispersing the above-mentioned components.

Specific examples of the ether solvents include ethyl cellosolve (EC), propylene glycol monomethyl ether (PGM), methyl cellosolve (MC), propylene glycol propyl ether, ethylene glycol isopropyl ether, and the like. It can be mixed and used. The content of the ether solvent in the total composition is 3 to 10% by weight.

Specific examples of the C _1-7 alcohol solvent include methanol (MeOH), ethanol (EtOH), isopropyl alcohol (IPA), normal propyl alcohol (NPA), normal butyl alcohol (NBA), diacetone alcohol (DAA), and the like. It can be used individually or in mixture of 2 or more types. The content of the alcohol solvent in the total composition is 59.7 to 76.9% by weight.

In order to prepare the coating liquid composition of the present invention, first, an aqueous solution of PEDT conductive polymer is added to a container having a predetermined capacity, followed by vigorous stirring, and then an alcohol solvent, an ether solvent, and a silane coupling agent are sequentially added, followed by stirring at room temperature for about 3 hours. To complete the coating solution. After the coating solution is completed, it is recommended to filter using a 10.0 micron filter to remove foreign substances. In addition, it is good to allow the coating liquid to pass through the filter at its own weight without applying additional pressure as much as possible.

Hereinafter, a step-by-step description for forming a high-permeability conductive film using the high-permeability conductive coating liquid composition using the conductive polymer of the present invention as follows:

i) The coating liquid composition of the present invention prepared as described above on the PET film (125um) is coated through a microgravure (Micro Gravure) method. Microgravure coating has the advantage of being able to obtain a thinner and smoother substrate than any other coating method and is not limited by the size of the coated substrate. During the microgravure coating, the substrate running speed is 10 to 20mpm, and the microgravure coating roll mesh used is suitable for the 150-180 mesh.

ii) After the coating, the baking process is performed for 3 to 5 minutes at 120 to 150 ° C. to obtain a high permeability conductive coating film.

The coating film of the present invention prepared as described above has a surface resistance of 10 ³ to 10 ⁴ Ω / □, transmittance of 89% to 90%, hardness of 1H ~ 2H.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Examples 1 to 4 Preparation of the coating solution and conductive film production according to the present invention

According to the composition shown in Table 1 below, a solution of a predetermined capacity of PEDT conductive polymer (1.3% by weight) was first added to a container of a predetermined capacity, while stirring vigorously, IPA, ethanol, a silane coupling agent, and PGM were added and stirred at room temperature for 3 hours. After filtering with a 10.0 micron filter to complete the coating solution composition.

In the above, Baytron PH of Bayer Corp. was used as aqueous solution of PEDT conductive polymer, and triglycidoxypropyltrimethoxysilane of GE-Toshiba Corp. was used as binder.

In addition, to produce a conductive film, the coating liquid composition of the present invention prepared as described above on the PET film (125um) to form a coating layer by microgravure coating. At this time, the progress rate during microgravure coating was adjusted to 20mpm, and the coating mesh bar size used was 180 mesh. After coating, the baking process was performed at 150 ° C. for 5 minutes to obtain a high permeability conductive coating film.

division Furtherance Example 1  PEDT (1.3 wt%, aq) 20 wt% IPA 24.8 wt% EtOH 50 wt% PGM 5 wt% Samglycidoxypropyltrimethoxysilane 0.2 wt% Example 2  PEDT (1.3 wt%, aq) 22 wt% IPA 24.8 wt% EtOH 48 wt% PGM 5 wt% Samglycidoxypropyltrimethoxysilane 0.2 wt% Example 3  PEDT (1.3 wt%, aq) 24 wt% IPA 24.8 wt% EtOH 46 wt% PGM 5 wt% Samglycidoxypropyltrimethoxysilane 0.2 wt% Example 4  PEDT (1.3 wt%, aq) 26 wt% IPA 24.8 wt% EtOH 44 wt% PGM 5 wt% Samglycidoxypropyltrimethoxysilane 0.2 wt%

IPA: Isopropylalcohol (Isopropyl alcohol)

     PGM: Propyleneglycol monomethyl ether

The physical properties of the coating film formed as described above were evaluated by surface resistance per unit area using Loresta (4-point probe) manufactured by Mitsubishi Chemical in the case of conductivity, and the transmittance was measured using PSI transmittance measuring instrument (DARSA PRO-5000). It was evaluated using a transmittance at 550nm, the film hardness was measured using a pencil hardness tester and shown in Table 2. In the case of luminance, the conductive film was mounted on a direct backlight having a film array as shown in FIG. 2, and evaluated using a luminance meter (LS100) manufactured by MINOLTA. In addition, the degree of screen failure (waterfall) was visually observed and shown in Table 4.

division Properties of Coating Film Surface Resistance (Ω / □) Permeability (T%) Film hardness Exterior Example 1 3.0E04 90.1 1H Transparency Example 2 1.2E04 89.9 1H Transparency Example 3 8.5E03 89.5 1H Transparency Example 4 5.0E03 88.7 1H Transparency Comparative example 1.0E03 86.5 1B Transparency

* Comparative example: Ichitobi's ITO thin film conductive film is used

Original position Change location Backlight Configuration DBEF-D Prism Film Diffusion Film ITO Film (Comparative Example) Diffusion Plate CCFL DBEF-D Prism Film Diffusion Sheet Conductive Film (Example 1) Diffusion Plate CCFL ITO Film (Comparative Example) DBEF-D Prism Film Diffusion Film Diffusion Plate CCFL Conductive Film (Example 1) DBEF-D Prism Film Diffusion Sheet Diffusion Plate CCFL Average luminance (cd / ㎡) 7587 7527 8035 8020 Luminance Ratio (%) 91 90 96 96

-Module evaluation: Measurement after 1 hour annealing

-Spec. : LTA320W1-L01ver.21 Matsushita flavor (CCFL Backlight Unit, using synchronous inverter) Measured after 2 hours annealing

Comparative example Example 1  Screen fallout rate medium Mimi

From Tables 2, 3, and 4, the transmittance, surface resistance, and film hardness of the high-permeability conductive film using the conductive polymer according to the present invention are at least equivalent to those of competing ITO products, and particularly in the backlight of large-sized LCD-TV panels. When installed, it can be seen that there is an improvement in waterfall screen defects, which are apparent defects caused by electromagnetic waves.

As described in detail above, the coating liquid composition of the present invention is excellent in conductivity and at the same time has a high transmissive property, it is useful for large-size film coating at the same time to remove the screen (Waterfall) due to the electromagnetic wave effect in LCD-TV.

Claims (7)

(a) polyethylenedioxythiophene (PEDT) doped with polystyrenesulfonate (PSS); (b) silane coupling agents; (c) ether solvents; And (d) A high permeability conductive film coating liquid composition comprising an alcohol solvent having 1 to 7 carbon atoms. The method of claim 1, (a) 20-30% by weight aqueous solution of polyethylenedioxythiophene (PEDT) doped with polystyrenesulfonate (PSS) (solid content 1.2-1.5% by weight); (b) 0.1 to 0.3% by weight of alkoxysilane; (c) 3 to 10% by weight of an ether solvent; And (d) 59.7 to 76.9% by weight of an alcohol solvent having 1 to 7 carbon atoms is added thereto to form a highly permeable conductive film coating liquid composition. 3. The silane coupling agent according to claim 1 or 2, wherein the silane coupling agent is vinyltrimethoxysilane, vinyltriethoxysilane, gamma chloropropyltrimethoxysilane or enbetaaminoethyl. Gamma aminopropyltrimethoxysilane (N-β- (aminoethly) -γ-aminopropyltrimethoxysilane), gamma glycidoxypropyltrimethoxysilane, gamma-mecaptopropyltrimethoxysilane, And triglycidoxy propyl trimethoxysilane (3-glycidoxypropyltrimethoxysilane) is one or more materials selected from the group consisting of, The ether solvent is at least one material selected from the group consisting of ethyl cellosolve (EC), propylene glycol monomethyl ether (PGM), methyl cellosolve (MC), propylene glycol propyl ether, ethylene glycol isopropyl ether , The alcohol solvent is at least one selected from the group consisting of methanol (MeOH), ethanol (EtOH), isopropyl alcohol (IPA), normal propyl alcohol (NPA), normal butyl alcohol (NBA) and diacetone alcohol (DAA) High permeability conductive film coating liquid composition, characterized in that the material. Method for producing a high permeable conductive film comprising the following steps: i) microgravure coating the coating liquid composition of claim 1 on a PET film; And ii) heating the coating layer at 120-150 ° C. for 3-5 minutes.        The method of claim 4, wherein The microgravure coating at a speed of 10 ~ 20mpm, the coating mesh bar size is a manufacturing method of a high permeability conductive film, characterized in that carried out at 150 ~ 180. A highly permeable conductive film having the characteristics of surface resistance 10 ³ to 10 ⁴ Ω / □, transmittance of 89% to 90% and hardness of 1H to 2H produced by the method of claim ⁴ . A backlight comprising the high permeable conductive film of claim 6.

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