KR100404873B1 - Conductive polymer cathod ray tube coating layer and composition for porducing thereof - Google Patents

Abstract

The present invention relates to a conductive polymer CRT (cathod ray tube) coating layer, and a composition for forming the coating layer, more specifically, PEDT, conductive inorganic particles, C _{1 ~} C ₃ alcohol solvent, silica sol or alkyl silica sol, water-soluble Or a first coating layer formed of a first composition comprising an alcohol-soluble polymer, a water-dispersible carbon black, a water-dispersible color pigment, and a water-soluble or alcohol-soluble color dye, an alcohol solvent, a silcisol or an alkylsilica sol, and an acid catalyst from 0.1 to 0.1. It relates to a conductive polymer CRT coating layer consisting of a second coating layer formed by using a second composition comprising 0.5% by weight, the conductive polymer CRT coating layer capable of electromagnetic shielding function while having a low reflection and contrast enhancement properties according to the present invention Can be provided.

Description

Conductive polymer cathode coating layer and composition for forming the coating layer

The present invention relates to a conductive polymer CRT (cathod ray tube) coating layer and a composition for forming the coating layer, and more particularly, to a conductive polymer CRT coating layer and a coating layer formed to have a low reflection and contrast enhancement characteristics and also have an electromagnetic shielding function. It relates to a composition for.

As a conductive polymer compound, polyaniline, polypyrrol, polythiophene, and the like are widely used. These polymer compounds have attracted attention as synthetic metals because of their easy polymerization and excellent electrical conductivity, and have been proposed for their application as various conductive materials such as electromagnetic wave materials, secondary battery electrodes and transparent electrodes. However, due to the difficulty in processing and instability in heat, air and ultraviolet light, only a few examples of actual commercialization have been achieved.

In recent years, attention has been drawn to the conductive material by solving the above problems of the existing conductive polymer, polyethylene dioxyti, which is an alcohol-soluble polythiophene conductive polymer described in US Pat. Nos. 5,035,926 and 5,391,472. Offen (polyethylene dioxythiophene, hereinafter referred to as PEDT). The conductive polymer has excellent solubility, excellent air, heat and UV resistance as well as polyaniline and polypyrrole, as well as other conductive polymers of the same polythiophene type, so that the externally exposed area has been rarely used due to durability problems. It became possible to use as a conductive coating film. In particular, since the transmittance is excellent when forming a thin film, the use of CRT glass surface, transparent plastic surface (panel, film) and other transparent substrates, such as electromagnetic shielding material, antistatic material, has been proposed for use as a conductive coating material.

In the case of the metal oxide-based inorganic ITO (indiumtinoxide) thin film and PEDT thin film containing high refractive index (formerly Korean Patent Publication No. 2000-040197), which is used as the electromagnetic shielding coating material of CRT outer glass, it has high conductivity and less than 1%. In addition to having a low reflectivity function that reflects reflectivity and exhibits excellent coating properties such as very high transmittance (over 98%), it is pointed out that it is not suitable as a coating material for color plane CRT, which has recently been in the spotlight. The reason for this is that recently used color glass CRT outer glass shows more than 83% of permeability, so the contrast of flat CRT screen is increased when coating the existing high permeability, inorganic oxide thin film of ITO thin film or PEDT thin film including high refractive index This is because it is lowered and the sharpness is lowered. Therefore, in recent years, black colored coating liquids having low transmittance have been used for the outer glass of the color flat CRT. In the case of coating liquids developed for this purpose, carbon black is mostly dispersed in a transparent conductive solution. For example, a black coating liquid (US Pat. No. 5,681,885) in which carbon powder is dispersed in an ATO (antimonytinoxide) sol and a silica sol solution may be mentioned. In this case, the color is dark black or black brown, which is not excellent in appearance color characteristics, and not only deteriorates the sense of quality, but also uses non-conductive colorant so that the surface resistance of the film is about 10 ¹⁰ ~ 10 ¹¹ Ω / □, which is used only for antistatic. It cannot be used for electromagnetic shielding.

The present invention is to solve the problems of the prior art as described above, it is an object of the present invention to provide a conductive polymer CRT coating layer capable of electromagnetic shielding function while having a low reflection and contrast enhancement characteristics.

One aspect of the present invention for achieving the above object is PEDT, conductive inorganic particles, C _{1 ~} C ₃ alcohol solvent, silica sol or alkyl silicazol, water-soluble or alcohol-soluble polymer, water dispersible carbon black, water dispersible Using a first coating layer formed using a color pigment, and a first composition comprising a water-soluble or alcohol-soluble colored dye, and a second composition comprising an alcohol solvent, a silica key or an alkyl silicazol, and 0.1 to 0.5% by weight of an acid catalyst. It relates to a conductive polymer CRT coating layer consisting of a second coating layer formed.

Another aspect of the present invention for achieving the above object is to form a first coating layer using the first composition, and then to form a second coating layer using a second composition thereon for 30 minutes at 150 ~ 200 ℃ It relates to a CRT coating layer forming method comprising the step of heat-fired for about 1 hour.

Hereinafter, the present invention will be described in more detail.

The first composition used in the first coating layer of the present invention is a PEDT, conductive inorganic particles, alcohol solvent, alkoxy silane, water-soluble or alcohol-soluble polymer, water-dispersible carbon black covalently bonded hydrophilic group, water-dispersible colored pigment and water-soluble or alcohol-soluble A color dye is prepared, and the second composition used in the second coating layer is prepared including an alcohol solvent, an alkoxysilane and an acid catalyst.

In the present invention, in order to compensate for the disadvantage that the resistance is increased by adding non-conductive materials such as carbon black and colored pigments, water-soluble or alcohol-soluble colored dyes to the conventional coating liquid, the coating liquid is used to form the first coating layer and the second coating layer. It is composed to form, and improves the contrast of color flat tube by adding water-dispersible carbon black, water-dispersible colored pigment, water-soluble or alcohol-soluble colored dye with covalently bonded hydrophilic group to the first composition to reduce the permeability of coating film. At the same time, by forming an inorganic-organic hybrid coating film on the first coating layer, a low reflection and contrast enhancement and a electron shielding function are also enabled by a method of compensating for the reduced conductivity. In addition, since the surface film hardness is weak in the conventional antireflective coating, the film hardness is increased by forming the second coating layer using the second composition.

The component which comprises the composition of this invention is demonstrated in detail as follows.

In the first composition of the present invention, a polythiophene-based water-soluble PEDT is used as the conductive polymer. Especially, the dopant-doped polystyrene sulfonate (PSS) exhibits good water solubility, and shows thermal stability, moisture stability, and UV. It is preferable because of its excellent stability. Hereinafter, PEDT used in the composition of the present invention refers to a state containing a dopant. This PEDT can be easily coated by diluting with these solvents because it is well mixed with solvents having a high dielectric constant such as water, alcohol and amide solvents, and polyaniline and polypyrrole, which are other conductive polymers when the coating film is formed It shows excellent transparency compared with that.

The content of PEDT is appropriately 0.02 to 0.4% by weight of the total composition, it is used in the aqueous solution. If the content is less than 0.02% by weight, there is a problem that the surface resistance exceeds 10 ⁸ Ω / □, which is the minimum conductivity value of the commercially available conductive thin film, and when the content exceeds 0.4% by weight, the conductivity is excellent. However, since PEDT and high refractive inorganic sol gel in solution, they are not suitable for CRT exterior glass coatings requiring high uniform thickness. It is preferable to adjust and use an aqueous solution so that it may become 2-25 weight%.

In the first composition of the present invention, inorganic conductive particles having excellent conductivity and chemically stable properties were used. Specifically, conductive inorganic particles such as Ag-Au, Ag-Ru, and Ag-Pd were used. The inorganic conductive particles hybridize with PEDT, a conductive polymer, to maintain an appropriate film thickness. The content of the inorganic conductive particles is 0.05 to 0.5% by weight of the total composition, it is preferable to use 40 to 80% by weight diluted with a solvent.

The alcohol solvent used in the first composition of the present invention is suitable for low boiling alcohols having 1 to 3 carbon atoms such as methanol, ethanol and isopropanol, and more preferably methanol. In the case of mixing two or more kinds of the alcohol, at least 50% of methanol should be included to have good dispersibility. The content of the alcohol solvent is suitably 15.7 to 40% by weight.

PEDT conductive polymer is doped with polystyrenesulfonic acid (-SO ₃ H, -SO ₃ -Na), which serves as a dispersant, to help disperse the conductive polymer itself, but when the amount of the aqueous solution of PEDT conductive polymer is less than 10% by weight And when the surface is not clean when the CRT panel outer glass surface is coated, the first composition includes a water-soluble or alcohol-soluble polymer resin because the PEDT conductive polymer itself does not have sufficient dispersibility and adhesion to the substrate surface.

Specific examples of such water-soluble or alcohol-soluble resins include polymethylmethacrylate (PMMA), polyacrylate (PA), polyvinyl alcohol (PVOH), polyvinyl acetal (PVAT), polyvinylbutylal (PVB), methylcellulose (MC), hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), polyvinylacetate (PVAc), hydroxypropylmethylcellulose (HPMC) and the like. Such resin binders are preferably added in the form of a solution (alcohol or aqueous solution), and the amount of the binder is preferably 0.005 to 0.1% by weight based on solids. If the content is less than 0.005% by weight does not exhibit the effect of the substrate adhesion desired in the present invention, the dispersibility is inhibited, if the content exceeds 0.1% by weight the viscosity of the composition is increased, the comb pattern after spin coating, such as a uniform film It is not preferable because a problem occurs that is not formed.

Hereinafter, the colorant included in the first composition of the present invention will be described.

The water-dispersible carbon black contained in the first composition of the present invention uses a water-dispersed carbon that is surface-modified (covalently bonded) with a sulfonate and carboxylate group which are completely different from the usual ones. When the water-dispersible carbon black is used, a stable dispersion state is maintained in water or an alcohol solvent without adding organic substances such as surfactants, dispersants, or polymers that are commonly used to maintain stable dispersibility of carbon. Therefore, when the antistatic black coating film is formed of such a material, excellent film hardness and high optical density can be obtained, and there is little elution of black color from the film surface. In particular, sulfonates and carboxylates present in these carbon powders can act as a doping agent for PEDT conductive polymers such as monomer dopants, which are the aforementioned conduction aids. Since it maintains a stable dispersion state in water or alcohol, there is almost no appearance defect due to the radial pattern of the coating film which is often found in the case of carbon dispersed with ordinary organic materials even when a high content of carbon is used. Appearance properties are good and can exhibit very low permeability.

In the present invention, when the water-dispersible carbon alone is used, the color characteristics have a dark brown color, and thus the color characteristics are not high-grade, and thus are not suitable where a high-quality appearance and color such as CRT are desired. Therefore, in order to overcome these disadvantages, water-dispersible colored pigments are mixed and used in a dispersed state. As an example of such a water-dispersible colored pigment used in the present invention, a conventional one can be used. That is, blue, violet, red, and yellow pigments in a form dispersed in water may be used. These are conventionally prepared using methods of dispersing pigments. That is, it is the form disperse | distributed to the beads etc. using water-soluble dispersing agents, such as polystyrene sulfonate, and a normal water-soluble surfactant. Since these water-dispersible colored pigments are used to reinforce the color of the water-dispersible carbon black mentioned above, the amount used is equal to or less than that of the water-dispersible carbon black.

In the present invention, the amount of water-dispersible carbon black is suitably 0.1 to 0.3% by weight, and the amount of water-dispersible colored pigment is 0.05 to 0.25% by weight. When it is out of the above range, not only the target transmittance of 40 to 80% can be achieved, but also precipitation and unevenness of the CRT screen occur, which is not preferable because the black characteristic of the present invention becomes a weak color.

In the present invention, when only the water-dispersible carbon and colored pigments are used, the color properties are excellent, but the conductivity is lowered by increasing the surface resistance of the coating. In the present invention, by developing colorants to improve the conductivity, not only have a colored color, which is the object of the present invention, but also improve the film conductivity. These colored dyes are azochrome complex dyes and anthraquinone dyes having a hydrophilic group having an alcohol-soluble property and excellent compatibility with the conductive solution of the present invention. These colored dyes are those having excellent compatibility with the conductive solutions of the present invention, and representative examples of these include PC-Black 006P (azochrome complex dye) and PC-Black 206P (azochrome complex dye) of Nippon Gunpowder. And PC-Blue 43P (anthraquinone dye).

The content of the colored dye in the composition of the present invention is suitable 0.05 to 0.25% by weight. The use of less than 0.05% by weight does not lead to an improvement in conductivity, which is an object of the present invention, and when it exceeds 0.25% by weight, the black color property is very weak, which is not preferable.

In the second composition of the present invention, an alkoxy silane and an acid catalyst are added to an alcohol solvent to form silica sol. Included alkoxy silanes are also used in the first composition together with tetraalkoxysilanes (preferably Si (OR ') ₄ , which is R' = methyl or ethyl) or alkyltrialkoxysilanes (preferably R = methyl, R '= RSi (OR ') ₃ ,) which is a methyl group or an ethyl group can be used. Such alkoxysilanes are reacted with water or an additionally added alcohol solvent in the aqueous solution of PEDT to undergo hydrolysis and condensation reactions, followed by silica sol (-SiO ₂ -SiO _2- ) and alkylsilazole (R-SiO ₂ -SiO _2- ). These silica sols are coated with a thin film and thermally cured to form polysilicate crystals, thereby increasing the film hardness.

The content of the silica sol or alkoxy silica sol is 2 to 5% by weight is appropriate. If the content is less than 2% by weight, hardness of more than 5H cannot be achieved. If the content is more than 5% by weight, the hardness is very good, but the amount of polysilicate that adversely affects the conductivity is increased so that the level of electromagnetic shielding level is 10 ² The surface resistance of ˜10 ³ Ω / □ (measured value after formation of the first and second coating layers) cannot be achieved.

The alcohol solvent used may specifically include methanol, ethanol, isopropyl alcohol, 2-ethoxy alcohol, 2-butanol, diacetone alcohol, and the like, but is not limited thereto.

As the catalyst used, conventional acids such as sulfuric acid, nitric acid and hydrochloric acid may be used.

It is also possible to further add a small amount of the aqueous solution of PEDT to the second composition as necessary.

The first composition of the present invention is an aqueous solution of covalently bonded alcohol solvent, inorganic conductive particle solution, alkoxy silane, water-soluble or alcohol-soluble resin binder solution, hydrophilic group is added while vigorously stirring PEDT conductive polymer aqueous solution in a predetermined amount of container Carbon black, water-dispersible colored pigments, and water / alcohol soluble colored dyes may be added in order and prepared by stirring sufficiently for about 3 to 5 hours at room temperature. In consideration of the solution stability aspect, when added and mixed in the above order, it exhibits the best solubility and dispersibility, thereby producing a highly uniform coating film.

In the case of the second composition, an alcohol solvent, tetraalkoxysilane or alkyltrialkoxysilane, and an acid catalyst are sequentially added and stirred for at least 6 hours to prepare a silazazole solution.

Hereinafter, a method of manufacturing a conductive polymer black colored coating film for electromagnetic shielding having low reflection and contrast enhancement characteristics on CRT outer glass using the first and second compositions will be described.

1) The CRT outer glass is polished with CeO ₂ , washed with ethanol and dried.

2) The first composition of the present invention is coated on the CRT outer glass surface by spin coating or other method and dried to form a first coating layer. The rotation speed is suitably 80 to 150 rpm, and the time is suitably 60 to 100 seconds.

3) The second composition of the present invention is coated and dried on the first coating layer by spin coating or other method to form a second coating layer. The rotation speed is suitably 80 to 150 rpm, and the time is suitably 60 to 100 seconds.

4) Finally, the conductive polymer CRT coating layer of the present invention may be formed by drying at 150 to 200 ° C. for 30 minutes to 1 hour to form a hard film.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are for the purpose of explanation and are not intended to limit the present invention.

Example 1-8

At the mixing ratio shown in Table 1, the solution of inorganic conductive particles dispersed in methanol or water, alcohol solvent, water dispersible carbon black, water dispersible color pigment, and water soluble or alcohol soluble color was first added to the aqueous solution of PEDT conductive polymer and vigorously stirred. Dye was added sequentially and stirred sufficiently at room temperature for 3 to 5 hours to prepare a first composition.

Then, 6 g of TEOS (Tetraethylorthosilicate), 3 g of ethanol, and 2 g of 0.175 M hydrochloric acid were stirred for about 1 hour while raising the temperature to 60 to 65 ° C. The second solution was prepared by stirring 34.4 g of ethanol, 36.9 g of 2-butanol, and 4.7 g of ethanol containing 1 wt% of Silwet 7001, which is a surfactant, and stirred for about 1 hour.

The coating composition prepared as described above was spin-coated and dried for 60 to 100 seconds at a speed of 80 to 150 rpm on the dried glass surface by washing with acid using a first composition. Next, on the surface on which the first coating layer was formed, the second composition was spin-coated again in the same manner using the second composition to form a second coating layer. Finally, it was dried for 30 to 60 minutes at 150 to 200 ℃ to form a hard film.

weight% PEDT1.3%, aq Alcohol solvent (MeOH) Ag-Au inorganic particles0.4%, aq Water Soluble Polymer (HPC) 1%, MeOH Alkoxysilane (TEOS) Water Dispersible Carbon Black (CB200) 5%, aq Disperse colored pigment (GA violet) 5%, aq Alcohol soluble colored dye 5%, MeOH Example 1 4 42 40 One 5 3 2 PC-Blue3 Example 2 6 43 40 One 4 3 One PC-Blue2 Example 3 8 44.5 40 One 2 3 0.5 PC-Blue1 Example 4 10 40 40 One 5 2 One PC-Blue1 Example 5 4 32.5 50 One 4 2 0.5 PC-Blue1 Example 6 6 28 60 One 2 2 0.5 PC-Blue0.5 Example 7 8 15.5 70 One 3 One 0.5 PC-Blue1 Example 8 10 15.5 7 One One One 0.5 PC-Blue1

PEDT (Polyethylenedioxythiophene): Baytron PH 4071 from Bayer

* HPC (hydroxypropyl cellulose): Aldrich

TEOS (tetraethoxysilane): Aldrich

* CB200 (sulfonate carbon black): Cabot

* GA violet: Mikuni Color

* PC-Blue43P (Anthraquinone): Japanese Gunpowder

Conductivity (Ω / □) Permeability (T%) Hardness (H) reflectivity(%) Exterior Example 1 850 65 8 0.6 Black Blue Example 2 770 770 8 0.6 Black Blue Example 3 760 760 7 0.5 Black Blue Example 4 640 640 7 0.5 Black Blue Example 5 780 780 8 0.6 Dark brown Example 6 730 730 7 0.5 Dark brown Example 7 630 630 7 0.5 Dark brown Example 8 470 60 6 0.4 Dark brown

[Measurement of physical properties]

* Surface resistance: Mitsubishi Chemical's Loresta (4-point probe) is used

* Transmittance: Measured at 550nm using UV-Visible Spectrometer

* Film hardness: measured using a pencil hardness tester

According to the present invention, it is possible to provide a conductive polymer coating film for a CRT, which can have an electromagnetic shielding function while having low reflection and contrast enhancement characteristics.

Claims (8)

2 to 25% by weight aqueous solution of PEDT having a PEDT content of 0.02 to 0.4% by weight based on the first composition, 40 to 80% by weight of conductive inorganic particle solution having a content of the conductive inorganic particles 0.05 to 0.5% by weight based on the first composition, C ₁ 15.7-40 wt% of C- ₃ alcohol solvent, 2-5 wt% of silica sol or alkyl silicazol, 0.005-0.1 wt% of water-soluble or alcohol-soluble polymer, 0.1-0.3 wt% of water-dispersible carbon black, water-dispersible color pigment 0.05 A first coating layer formed by using a first composition composed of -0.25 wt% and 0.05-0.25 wt% of a water-soluble or alcohol-soluble colored dye, and A conductive polymer CRT coating layer comprising a second coating layer formed by using a second composition comprising 94.5 to 99.9 weight% of an alcohol solvent, 2 to 5 weight% of a silica sol or alkyl silicazol, and 0.1 to 0.5 weight% of an acid catalyst. As a first composition for forming the first coating layer of claim 1, 2-25 wt% of an aqueous PEDT solution having a PEDT content of 0.02-0.4 wt% based on the total composition, 40 to 80 wt% of the conductive inorganic particle solution having a conductive inorganic particle content of 0.05 to 0.5 wt% based on the total composition, 15.7~40 wt% of an alcohol solvent of C ₁ ~C _3, 2-5% by weight of silica sol or alkylsilica sol 0.005 to 0.1% by weight of a water-soluble or alcohol-soluble polymer, 0.1-0.3 wt% of water dispersible carbon black, Water dispersible color pigments 0.05 to 0.25 wt%, and A composition for a CRT first coating layer comprising 0.05 to 0.25 wt% of a water-soluble or alcohol-soluble colored dye. As a second composition for forming the second coating layer of claim 1, Alcohol solvent 94.5 to 99.9 wt%, 2-5% by weight of silica sol or alkylsilica sol, and The composition for CRT 2nd coating layers which consists of 0.1-0.5 weight% of an acid catalyst. 4. The composition for CRT second coating layer according to claim 3, wherein PEDT is further added. The conductive polymer CRT coating layer according to claim 1, wherein the silica sol or alkylsilazole is produced from tetraalkoxysilane or alkyltriethoxysilane. The composition according to claim 2 or 3, wherein the silica sol or alkylsilazole is produced from tetraalkoxysilane or alkyltriethoxysilane. The method of claim 1, wherein the water-soluble or alcohol-soluble polymer is polymethyl methacrylate (PMMA), polyacrylate (PA), polyvinyl alcohol (PVOH), polyvinyl acetal (PVAT), polyvinyl butylal (PVB) Conductive polymer CRT coating layer, characterized in that selected from the group consisting of methyl cellulose (MC), hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), and polyvinylacetate (PVAc). The conductive polymer CRT coating layer of claim 1, wherein the conductive inorganic particles are selected from the group consisting of Ag-Au, Ag-Ru, and Ag-Pd.