JPS62158136A - Glass substrate - Google Patents

Abstract

PURPOSE:To obtain a glass substrate coated with a material having high effect for inhibiting diffusion of alkali metal ion component by forming a thin film of mixed oxides consisting of SiO2 admixed with a specified metal oxide and oxide of P to an alkali glass plate. CONSTITUTION:The glass substrate is coated with thin film of mixed oxides based on SiO2 contg. at least one metal oxide among Al, Cr, Mo, Fe, and Sn together with oxide of P. The thin film of mixed oxides to be coated has a compsn. consisting of 0.5-20wt% metal oxide except SiO2, 0.5-20wt% oxide of P expressed in terms of P2O5, and residual wt% SiO2. Chlorides, nitrates, alkoxides, and chelated complexes obtd. by reacting said compds. with chelating agents are preferred as metal compd. to be used because of their high solubility in org. solvents and high stability of coating liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a glass substrate, and more particularly, an alkali glass (soda lime) coated with a mixed oxide thin film mainly composed of silicon oxide (Sift). silica glass)
This invention relates to a glass substrate made of a plate.

The glass substrate of the present invention can be suitably used as a transparent substrate for a conductive glass body coated with a transparent conductive film because the mixed oxide thin film has an excellent ability to prevent ion diffusion of alkali metal components from the alkali glass plate. can.

[Conventional technology]

Transparent electrodes used in display elements such as liquid crystal display elements, electrochromic elements, and electroluminescent elements, as well as amorphous solar cells, are made by coating a transparent substrate with an ITO film (tin-doped indium oxide film) or an FTO film (fluorine-doped indium oxide film). Transparent conductive metal oxide thin films (hereinafter referred to as indium oxide 1) 90, NESA film (7-inch doped tin oxide film), etc.
It is simply called a "conductive film." ) is manufactured by etching and patterning a conductive film on a conductive glass body coated with a conductive glass body.

As a transparent substrate for these conductive glass bodies, an alkali glass plate coated with a SiO□ thin film is often used.

The alkali glass plate contains 10 to 20 weight percent of alkali metal components such as sodium and potassium, and this alkali metal component has a property of being extremely easily transferred by ion diffusion and the like.

For example, in a conductive glass body in which an alkali glass plate is directly coated with a conductive film, an alkali metal component migrates into the conductive film by ion diffusion, resulting in a decrease in conductivity. Also,
When a transparent electrode processed from this conductive glass body is used in a liquid crystal display element, an oxidation-reduction reaction occurs on the electrode surface due to the alkali metal component transferred to the conductive film, which not only reduces the transparency of the conductive film but also causes Also, alkali metal components are eluted, and when voltage is applied, the liquid crystal electrolyzes and rapidly deteriorates.

Since the SiO□ thin film has the best ability to prevent ion diffusion of alkali metal components among metal oxides, an alkali glass plate coated with the SiO□ thin film is used as the substrate of the conductive glass body.

The methods for coating the alkali glass plate with the 5i (hF! film) include vacuum evaporation, sputtering, and chemical vapor deposition (CV).
, D method) and the coating and baking method (sol-gel method), each of which has its own characteristics, but for the production of transparent substrates of conductive glass bodies for transparent electrodes of liquid crystal display elements, it is necessary to use large-area substrates. The coating and firing method, which allows mass processing, is widely used.

As a coating liquid for forming Si0g thin film by coating and baking method,
It is recommended to use a reaction solution obtained by adding an inorganic acid to a mixture consisting of an alkoxysilane, an organic carboxylic acid, and an alcohol, and allowing the reaction to occur until the free alkoxysilane and organic carboxylic acid become less than 20% by weight of the original amount. It is disclosed in Japanese Patent No. 34234. In the example of the publication, this coating liquid is applied to a substrate and heated to 500°C.
A thin film coating of Sin was obtained by heat treatment at a temperature of 30 seconds.

On the other hand, highly durable Si0 with excellent salt water resistance and steam resistance
g thin film A It , Ga, Iu, YSLa
JP-A-57-100940 discloses a SiO□ thin film containing an oxide of a metal selected from the group consisting of Ce and Ce. In this publication, when the Si0g thin film coating is formed on a substrate by a coating and firing method, the higher the firing temperature, the higher the adhesion of the SiO□ thin film to the substrate, and the more the SiOg thin film is coated on the substrate, the better the SiOg thin film is coated on the substrate. Assuming that a thin film is obtained,
In the example, firing was performed at a temperature of 550° C. for 10 minutes.

[Problem that the invention seeks to solve]

As shown in the above reference, the higher the firing temperature is, the denser and better quality 5iOtTiI\l coating can be obtained, but when coating an alkali glass plate with a SiO□ffl film, the firing temperature must be lower than the deformation temperature of the alkali glass plate. Generally, it is fired at a temperature of 550°C or lower.

The alkali glass plate was coated with a thin film of SiO□, which has an excellent ability to prevent the ion diffusion of alkali metal components, according to the above-mentioned Japanese Patent Publication No. 56-3.
When forming using the coating liquid disclosed in Publication No. 4234, it is necessary to bake at a temperature of 500 to 550'C for about 30 minutes. Prevention ability decreases.

On the other hand, in Japanese Patent Application Laid-open No. 57-100940, SiO□
Although the durability of the thin film such as salt water resistance and steam resistance is mentioned, there is no mention of the ability of the SiO□ thin film to prevent ion diffusion of alkali metal components.

It is also said that the higher the firing temperature during coating formation of the 5iOz thin film, the better.

The present invention aims to provide a glass substrate coated with a mixed oxide thin film mainly composed of Sin, which is obtained by firing at a temperature below the deformation temperature of an alkali glass plate and has an excellent ability to prevent ion diffusion of alkali metal components. , its purpose.

[Means for solving problems]

The present inventors have discovered that a mixed oxide thin film coating made by adding a specific metal oxide and phosphorous oxide to Sing becomes dense even when fired at a relatively low temperature, and has excellent ion diffusion prevention of alkali metal components. The present invention was completed based on this discovery.

The present invention is based on Alt, Cr, MO% Pe and S
The present invention is a glass substrate consisting of an alkali glass plate having a coating of a mixed oxide thin film based on silicon oxide containing an oxide of at least one metal selected from the group consisting of n and phosphorus oxide.

In the present invention, SiO coated on an alkali glass plate
The mixed oxide thin film mainly consists of 0.5 to 20% by weight of metal oxides other than 5ift, preferably 1 to 10% by weight, 0.5 to 20% by weight of phosphorous oxides as P2O, and the remainder. It has a composition of 5iO1.

The glass substrate of the present invention comprises a partially hydrolyzed condensate of alkoxysilane, A 1 , Cr-, MO, , Fe and Sn
A solution prepared by dissolving an organic solvent-soluble compound of at least one metal selected from the group consisting of phosphorus compounds in an organic solvent is used as a coating liquid, and the coating liquid is uniformly applied to an alkali glass plate and dried at 300 to 500°C. , preferably about 400
It can be produced by firing at a temperature of °C.

Preferably, the alkali glass plate after application of the coating liquid is dried at a temperature of 200 to 300°C.

In the present invention, the partially hydrolyzed condensate of alkoxysilane, which is a component of the coating solution, is a tetraalkoxysilane having an alkoxy group having 1 to 6 carbon atoms, such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetraisopropoxysilane, and tetraalkoxysilane. It can be obtained by reacting one type of n-butoxysilane, tetraphenoxysilane, etc. alone or a mixture of two or more types with water or water generated by an esterification reaction of an organic acid with an alcohol.

This reaction is preferably carried out in the presence of a catalytic amount of a mineral acid such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, or carbonic acid to promote the reaction.

Metal compounds that are components other than the partial hydrolysis condensate of alkoxysilane in the coating solution include halides, carboxylates, sulfates, nitrates, carbonates, hydroxides,
Solvent-soluble metal compounds such as alkylated compounds, alkoxides, and chelate complexes can be used.

In particular, chelate complexes made by reacting chlorides, nitrates, alkoxides, and chelating agents such as β-diketones, β-ketoesters, etc. have excellent solubility in organic solvents and can be applied stably. It is preferably used because a liquid can be obtained.

As the phosphorus compound that is a component of the coating liquid, phosphorus oxides, inorganic phosphates, organic phosphates, and organic phosphorus compounds can be used, and phosphorus pentoxide can be preferably used.

The coating liquid is a mixture of the components dissolved in an organic solvent or a reaction product thereof so that a thin film of the mixed oxide is formed when the coating liquid is thermally decomposed, and the concentration of the mixed oxide is 1. -20 weight percent solution.

As the organic solvent for dissolving the above components used in the coating liquid, lower alcohols, carboxylic acid esters of lower alcohols, ketones, polyhydric alcohols, ethers of polyhydric alcohols, and mixed solvents thereof are used.

The method of applying the coating solution to the alkali glass plate is not particularly limited as long as a coating film of uniform thickness is obtained, and examples include dipping method, spray method, spinner method, roll coating method,
Dipping allows the use of any method such as a conventional brushing method, makes it easy to control the film thickness, provides coatings with excellent uniformity, and allows mass processing of large-area substrates. law is preferably adopted.

[Effect]

In the glass substrate of the present invention, the mixed oxide thin film containing Sing as the main component coated on the alkaline glass plate is
By containing the oxide of at least one metal selected from the group consisting of IL-, Crs Mo, Fe, and Sn, and the phosphorus oxide, the firing temperature during formation of the thin film is lower than the deformation temperature of the alkali glass plate. The thin film becomes dense even at a temperature sufficiently lower than that, and ion diffusion of the alkali metal component from the alkali glass plate is prevented.

〔Example〕

The present invention will be explained in more detail with reference to Examples.

However, the scope of the present invention is not limited to the following examples.

In addition, in the following examples, "parts" and "%" represent weight basis unless otherwise specified.

(1) Preparation of coating solution (Coating solution-1) 125 parts of tetramethoxysilane, 584 parts of ethanol, and 0.3 parts of concentrated hydrochloric acid were charged into a reaction vessel containing a partially hydrolyzed condensate of alkoxysilane, and the mixture was stirred. After starting reflux, 54 parts of water was added dropwise. After dropping water, it was further kept under reflux for 10 hours, and the SiO□
A solution (coating liquid-1) containing a partially hydrolyzed condensate of alkoxysilane with a calculated concentration of 5% was prepared.

(Coating liquid-2) Phosphorus compound-containing alkoxysilane partial hydrolysis tank metal solution (Coating liquid-1) obtained above: 1000 parts, pt.

Add 1.25 parts of St.s; mix uniformly at room temperature,
Contains 2.5% P2O5i based on O□ (coating liquid -
2) was prepared.

(Coating liquid-3) In the aluminum compound solution reaction container,
After charging and mixing 179 parts of methanol and 20.4 parts of triisopropoxyaluminum, 12 parts of acetic acid
of the mixture was added dropwise, the temperature was raised while stirring, and the mixture was kept under reflux for 30 minutes. Next, 12.9 parts of 70% lactic acid was added, and the mixture was kept under reflux for 1 hour. The converted concentration of zO* is 5.0
% aluminum compound solution (coating liquid-3) was prepared.

(Coating liquid 4 to 1)) Metal compound mixed solution (Coating liquid-2) prepared above was added with AjICj! ff ・6H20
, (Coating/&-3), CrCj! s ・6tlJ,
Cr(CH*C00) s ・H, O1 gate o(1!5,
FeCj! s ・6HtO,Sn (CH3) zC
It z and 5nCj! 2.2H20 was dissolved and the oxide concentration was 5.0% based on the total oxide (coating solution 4 to 1).
) was prepared.

(Coating liquids 12 to 15) The above-prepared (coating liquid-2) and (coating liquid-3) were mixed, and A7! gos/(^12 zos +SiO□) conversion concentration is 2, 5.5. O17.5 and 10% (
Coatings *12 to 15) were prepared.

(2) Production of glass substrate A soda lime silica glass (alkali glass) plate was immersed in a dipping bath filled with each of the above-prepared (coating solutions 1 to 15) and pulled up at a constant speed of 20 cm/min. , 220''C, and fired for 30 minutes in an electric furnace at a preset temperature to obtain a glass substrate.

The firing temperatures are shown in Table 1.

(3) Evaluation of glass substrate (a) Hydrofluoric acid resistance (etching rate: ER) The glass substrate manufactured above was exposed to 47% HF at 20°C;
0% HN (h; 10 cc and distilled water; 600 c
After being immersed in the mixed solution of c, the level difference was measured using a surface roughness meter, and the etching rate: ER (people/m1n) was determined.

(Coating liquid 1), (Coating liquid 6) and (Coating liquid 1.2-1
Figure 1(a) shows the relationship between the etching rate of the glass substrate using 4) and the firing temperature, and the etching rate and A ff
i, 0. The relationship between CrzOs content and CrzOs content is shown in Figure 1 (b
).

(b) Surface resistance The surface resistance of the systems using (coating liquids 12 to 14) and (coating liquid 1) was measured by a four-terminal method. The measurement results are shown in Table 1.

(c) Amount of Na elution The above (coating liquid 1), (coating liquid 6) and (coating liquid 12 to A cell was produced by fixing the glass substrate manufactured using 15). Pour distilled water into this cell and seal it, 70% RH, 80%
After keeping the cell in a constant temperature bath for 45 hours, it was cooled to room temperature and subjected to atomic absorption spectrometry.
The amount was analyzed.

The relationship between the amount of Na elution and the firing temperature is shown in FIG. 2(a).

Moreover, the relationship between the Na elution amount and the A J zoi and Crz03 contents is shown in FIG. 2(b).

〔Effect of the invention〕

As shown in the above examples, the glass substrate of the present invention has a temperature sufficiently lower than the deformation temperature of the alkali glass plate (350 to
By having a coating of a mixed oxide thin film mainly composed of 5iOt containing various metal oxides and phosphorus oxides formed at a temperature of Therefore, the amount of Na elution and the etching rate are small.

In other words, this mixed oxide thin film has a high ability to prevent ion diffusion of alkali metal components and is a dense thin film.

Therefore, the glass substrate of the present invention can be used as a transparent substrate of a conductive glass body for a transparent electrode.

Furthermore, in the production of the glass substrate of the present invention, since the firing temperature is low, there are few occurrences of defective products due to deformation of the glass substrate, and the effect of energy saving is also large.

The present invention provides a glass substrate made of an alkali glass plate coated with a mixed oxide thin film that has an excellent ability to prevent ion diffusion of alkali metal components, and has extremely great industrial significance.

[Brief explanation of drawings]

Figure 1 (a) Relationship curve between firing temperature and etching rate for A i 203 containing system (a)^1tO1 containing system (b) SiOz only system Figure 1 (b) A I, 03 content and Cr
Relationship curve between zOs content and etching rate (a) Aj! , 03-containing system (b) CrzO, ,-containing system (a) A 1.0. Firing temperature of containing system and Na? ? Relationship curve with I output amount (a) AAzO3 containing system (b) SiOz only system Figure 2 (b) A I Js content and Cr2
Relationship curve between 0i content and Na elution amount (a) A1zo*-containing system (b) Crt (h-containing system"I +1 (a) Al2゜33,
. Al1203 (wt%) Figure 2 (b) Ordinary temperature ('C) A1203
(weight%)

Claims (2)

[Claims] (1) Alkaline glass coated with a silicon oxide-based mixed oxide thin film containing an oxide of at least one metal selected from the group consisting of Al, Cr, Mo, Fe, and Sn and a phosphorous oxide A glass substrate consisting of a plate. (2) The mixed oxide thin film is a metal oxide excluding silicon oxide; 0.5 to 20 weight percent and a phosphorus oxide; 0
．． The glass substrate according to claim 1, containing 5 to 20 weight percent.