JPH0352675A - Antistatic film - Google Patents

Abstract

PURPOSE:To efficiently obtain a superior antistatic film by coating a substrate with a soln. contg. ZnO sol formed by bringing a soln. contg. a Zn salt and at least one kind of precipitant into a reaction and by heating the coated substrate. CONSTITUTION:A soln. contg. a Zn salt such as An halide, sulfate, nitrate, acetate or perchlorate and at least one kind of precipitant such as ammonia, urea, amine compd. or amide compd. is adjusted to pH0.1-6 by adding hydrochloric acid, sulfuric acid, nitric acid, acetic acid, perchloric acid, etc. A glass or plastic substrate such as the panel of a cathode-ray tube, a glass plate for a copying machine, a panel for an instrument or a glass plate for a clean room is coated with a soln. contg. ZnO, Al- or In-doped ZnO sol formed by bringing the pH adjusted soln. into a reaction and the coated substrate is heated to a temp. below the b.p. of the used solvent such as water or alcohol. A superior antistatic film is efficiently obtd. by such a simple method as spray coating, spin coating or dipping.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an antistatic film applied to the surface of a substrate such as a cathode ray tube panel. [Prior Art] Because cathode ray tubes operate at high voltage, static electricity is induced on their surfaces when they are started up or shut down. This static electricity often causes dust to adhere to the surface, causing a decrease in contrast, or causing discomfort due to a mild electric shock when directly touched. In the past, many attempts have been made to apply antistatic films to the surface of cathode ray tube panels in order to prevent the above-mentioned problems. For example, as described in JP-A No. 63-76247, a method has been adopted in which the surface of a cathode ray tube panel is heated to about 350° C. and a conductive oxide layer such as tin oxide or indium oxide is formed using the CvD method. However, in addition to the equipment cost involved in this method, the cathode ray tube is heated to a high temperature, which may cause the phosphor inside the cathode ray tube to fall off.
There were problems such as a decrease in dimensional accuracy. Furthermore, tin oxide is the most commonly used material for conductive films, but it has the disadvantage that it is difficult to obtain high-performance films using low-temperature processing. [Problems to be Solved by the Invention] The present invention aims to eliminate the above-mentioned drawbacks of the prior art, and aims to provide a new high-performance antistatic film that can be heat treated at low temperatures. It is something to do. [Means for Solving the Problems] That is, the present invention has been made to solve the above-mentioned problems, and includes a solution of a 2n salt to which at least one of ammonia, urea, an amine compound, and an amide compound is added. The present invention provides an antistatic film characterized in that a solution containing a ZnO sol produced by a reaction is applied onto a substrate and then heated. In the present invention, ZnO or A is used as the conductive oxide.
ZnO doped with L In is used. Zn0 can be obtained by dissolving a precipitant such as Zn salt and urea in a solution whose pH has been adjusted in advance and heating the solution. The solvent is not particularly limited, but includes water, alcohol, ester,
Ether, or organic high dielectric constant organic solvents such as brobylene carbonate and γ-butyrolactone can be used. These can be used alone or in a mixed system. Also, considering the stability of the starting material in the solvent, preferred solvents include water, alcohol, and among alcohols, methanol, ethanol, propanol, butanol, etc. Also preferably used are polyhydric alcohols such as glycerin and ethylene glycol. Further, as a solvent, hydrochloric acid, sulfuric acid, nitric acid, acetic acid, perchloric acid, etc. are added in advance to adjust the pH to a range of 0.1 to 6, preferably 0.
It is necessary to adjust it to a range of 5 to 4. The 2n salt is not particularly limited, but halides such as chlorides, sulfates, nitrates, acetates, and perchlorates can be used. At this time, the same salts of Al and In as above were added to ZnO at an O. It is also possible to add it in a range of 1 to 30 mol%. Ammonia, urea, amine compounds, and amide compounds can be used as precipitants; examples of amine compounds include hexamethylene diamine and hexamethylenetetramine, and examples of amide compounds include acetamide. The amount of Zn salt and precipitant dissolved varies depending on the usage conditions of the resulting reaction solution, but is usually 0. A range of OIM to 3M is preferred. The heating temperature is below the boiling point of the solvent, i.e. 100% in the case of water.
It is possible to heat the ZnO sol to a temperature of 10 minutes to 6 hours, although it varies depending on the temperature.For example, in the case of 90°C, the reaction is generally completed in about 30 minutes, and a ZnO sol is produced. In the present invention, a solution containing a ZnO sol with a desired particle size and particle size distribution can be obtained by optimizing the Zn salt, the type and concentration of the precipitant, the type of solvent, the initial pH, and the heating temperature and time. Can be manufactured. In addition, in the present invention, the solution after the reaction can be used as a coating solution on the substrate as it is, but when the generated ZnO powder is collected and mixed with other substances, or when the starting material has low solubility and remains in the solution, It is also possible to filter the reaction solution and peptize the resulting ZnO powder again in an appropriate solvent using a device such as a ball mill, sand mill, homomixer, stirrer, or the like. In addition, the liquid containing ZnO sol used in the present invention includes:
SifORlx'R4-x (x = 3 +
．． 4, R: alkyl group) by adding a silicon compound such as
Various surfactants can be used to simultaneously precipitate ins and improve wettability with the substrate, and for example, linear sodium alkylbenzene sulfonate, alkyl ether sulfate, etc. may be added. Further, the content of ZnO in the liquid is preferably 0.1 to 30% by weight. In addition, for the purpose of obtaining ZnO doped with At or In, Z
n salt and AI salt. The fine powder obtained when reacting the solution containing In salt was heated to 0.5 to
You can also bake it for 24 hours. As the coating method, conventionally used methods such as spin coating, dip coating, spray coating, etc. can be suitably used. In addition, an anti-glare effect may also be imparted by spray coating to form irregularities on the surface. In that case, a hard coat such as a silica film may be provided on the product of the present invention, which serves as an anti-glare antistatic film. good. Furthermore, a non-glare coat of silica film having an uneven surface may be provided by spray coating on the antistatic film of the present invention. Similarly, ZnO such as magnesium fluoride fMgFx), silica [SiOzl, etc.
It is also possible to obtain an antistatic film with low reflection due to the multilayer interference effect by coating it with a liquid containing a material with a lower refractive index than that of the film so as to have an appropriate optical thickness. Substrates on which the antistatic film of the present invention is formed include cathode ray tube panels, copying machine glass plates, instrument panels, clean room glass, various glasses such as front plates of display devices such as CRTs and LCDs, and plastic substrates. be able to. As mentioned above, the solution containing the ZnO sol of the present invention can be used by itself as a coating solution on a substrate.
When a low boiling point solvent is used, a uniform Z can be obtained by drying at room temperature.
An nO film is obtained, but if a high boiling point solvent is used or the strength of the film is to be improved, the coated substrate is heated. The upper limit of heating temperature is usually determined by the softening point of the glass, plastic, etc. used for the substrate. Considering this point, the preferred temperature range is 100 to 400°C. [Example] The present invention will be explained below with reference to Examples and Comparative Examples. (Example 1) pH was adjusted to HNO. Zn (
Dissolve NOsl s・6H20 at a concentration of 0.25 mol #2, and further dissolve hexamethylenetetramine at a concentration of 0.025 mol.
It was dissolved at a concentration of ol/I2. Add 70g of ethanol to this solution, heat under reflux at 90°C for 30 minutes, and add 2% by weight of ethanol.
A ZnO sol solution was obtained. This solution was applied to the surface of a cathode ray tube panel using the Subin coating method at 1500 rpm for 5 seconds, and then heat treated at 200°C for 30 minutes to obtain a film of about 100 nm. The surface resistance of the coated pus was measured, and the surface of the film was rubbed 100 times using a commercially available eraser under a load of 1 kg, and the presence or absence of peeling of the film was visually observed. (Example 2) ZnCla was added to 30 g of water whose pH was adjusted to 2.0 with HCI.
The same procedure as in Example 1 was performed except that the solution was dissolved at a concentration of 0.25 mol/I2. (Example 3) Add Z to 100 g of water whose pH was adjusted to 2.0 with HNO s
Dissolve n(NOs1 16H*o at a concentration of 0.25 mol/I2, and further dissolve hexamethylenetetramine at a concentration of 0.025 mol/I2.
It was dissolved at a concentration of mol/42. This solution was heated under reflux at 90°C for 30 minutes to obtain a 2% by weight ZnQ sol solution.
This liquid was filtered, washed with water, and dried under vacuum at 100°C for 5 hours to obtain ZnO.
I got the result. These crystals were added to ethanol to a concentration of 3% by weight, and were mixed with a homomixer for 10 minutes (rotation speed 6).
00Orpm) dispersed. The following evaluation was performed in the same manner as in Example 1. (Example 4) Al fNOl) i is 2 mol% of A1 with respect to ZnO
The same procedure as in Example 1 was carried out except that Zn (NOI12.6H20) was added and dissolved in water so that the following results were obtained.

(Example 5) The same procedure as Example 1 was carried out except that the firing temperature was 400°C. (Example 6) The same procedure as in Example 1 was carried out, except that the coating liquid was a mixture of equal amounts of the reaction solution in Example 1 and a solution in which 3% by weight of ethyl silicate was added to ethanol. (Example 7) The procedure was carried out in the same manner as in Example 1, and an ethanol solution containing 3% by weight of MgFz fine powder, which is a low refractive index material, was applied onto the formed film using the Subin coating method at 2000 rpm and heated at 200°C.
A film was formed by heating for 30 minutes. (Example 8) Ammonium was used in place of hexamethylenetetramine in Example 1. The same procedure as in Example 1 was carried out except that the solution was dissolved at a concentration of 0.025 mol/42.

(Example 9) In place of hexamethylenetetramine in Example 1, 0.0% of urea was used. The same procedure as in Example 1 was carried out except that the solution was dissolved at a concentration of 0.013 mol/2.

(Example 10) The same procedure as in Example 1 was conducted except that acetamide was dissolved at a concentration of 0.025 mol/n in place of hexamethylenetetramine in Example 1. (Example 11) In2mo for ZnO using In(NO31i)
The same procedure as in Example 1 was carried out except that Zn (NOsl 2.6H.
Example 1 was carried out in the same manner as in Example 1, except for using an ethanol solution containing Table 1 [Effects of the Invention] According to the present invention, it is possible to efficiently provide an excellent antistatic film by a simple method such as spraying or subin coating, or immersing the substrate in a solution. The present invention has excellent productivity and does not require a vacuum, so the equipment may be relatively simple. In particular, it can be applied to large-area substrates such as CRT panel faces, and can be mass-produced, so it has extremely high industrial value.

Claims (1)

[Claims] 1. A solution containing a ZnO sol produced by the reaction of a solution containing a Zn salt and at least one of ammonia, urea, an amine compound, and an amide compound is applied onto a substrate and then heated and baked. An antistatic film characterized by being formed by 2. At least one of the solutions containing MgF_2 sol and silicon compounds in the solution containing ZnO sol produced by the reaction of a solution containing Zn salt and at least one of ammonia, urea, an amine compound, and an amide compound. An antistatic film characterized in that it is formed by applying a solution obtained by mixing a solution of seeds onto a substrate and then heating and baking it. 3. An antistatic film consisting of a multilayer film formed on a substrate, of which at least one layer is produced by the reaction of a solution containing Zn salt and at least one of ammonia, urea, an amine compound, and an amide compound. An antistatic film characterized in that it is formed by coating a solution containing a ZnO sol on a substrate and then heating and baking it. 4. The antistatic film according to any one of claims 1 to 3, comprising at least one of an Al salt and an In salt. 5. Produced by the reaction of a solution in which a Zn salt is added to a solution prepared with a pH in the range of 0.1 to 6 by addition of an acid, and at least one of ammonia, urea, an amine compound, and an amide compound is added. 5. The antistatic film according to claim 1, wherein the antistatic film is formed by applying a solution containing ZnO sol onto a substrate and then heating and baking it. 6. A glass article on which the antistatic film according to any one of claims 1 to 5 is formed. 7. A cathode ray tube on which the antistatic film according to any one of claims 1 to 5 is formed.