PRODUCTION METHOD OF SILICA FILM

Abstract

The present application relates to a method for producing a silica film, which includes a step of contacting a silica precursor layer formed of a silica precursor composition having a pH of 5 or less with a Lewis base, where the silica precursor composition includes a silica precursor formed from a silane compound and an acid catalyst. The present application can provide a method capable of forming a silica film having excellent resistance to a vertical load and a tangential load without going through expensive equipment or a high temperature process.

Claims

1. A method for producing a silica film comprising: a step of contacting a silica precursor layer formed of a silica precursor composition having a pH of 5 or less, with a Lewis base, wherein the silica precursor composition comprises a silica precursor formed from a silane compound and an acid catalyst.

2. The method for producing a silica film according to claim 1, wherein the silica precursor comprises a component of Formula 1: ##STR00006## wherein, n is a number of 2 or more.

3. The method for producing a silica film according to claim 1, wherein the silica precursor is included in the silica precursor composition in an amount of 5 to 60 wt %.

4. The method for producing a silica film according to claim 1, wherein the acid catalyst is one or more selected from the group consisting of hydrochloric acid, sulfuric acid, fluorosulfuric acid, nitric acid, phosphoric acid, hexafluorophosphoric acid, p-toluenesulfonic acid and trifluoromethanesulfonic acid.

5. The method for producing a silica film according to claim 1, wherein the silica precursor composition comprises 0.01 to 10 parts by weight of the acid catalyst relative to 100 parts by weight of the silica precursor.

6. The method for producing a silica film according to claim 1, wherein the silica precursor composition further comprises a solvent.

7. The method for producing a silica film according to claim 6, wherein the silica precursor composition comprises 40 to 300 parts by weight of the solvent relative to 100 parts by weight of the silica precursor.

8. The method for producing a silica film according to claim 6, wherein the solvent is a mixed solvent of water and one or more solvents selected from the group consisting of alcohol, ketone and acetate solvents.

9. The method for producing a silica film according to claim 8, wherein the solvent comprises 5 to 100 parts by weight of water relative to 100 parts by weight of the one or more solvents selected from the group consisting of alcohol, ketone and acetate solvents.

10. The method for producing a silica film according to claim 1, wherein the Lewis base has a pKa of 8 or less.

11. The method for producing a silica film according to claim 1, wherein the Lewis base has a boiling point in a range of 80 C. to 500 C.

12. The method for producing a silica film according to claim 1, wherein the Lewis base has a flash point of 80 C. or higher.

13. The method for producing a silica film according to claim 1, wherein the Lewis base has a room temperature vapor pressure of 10,000 Pa or less.

14. The method for producing a silica film according to claim 1, wherein the Lewis base is an amine compound or a phosphate compound.

15. The method for producing a silica film according to claim 1, wherein all the processes proceed at 350 C. or less.

Description

MODE FOR INVENTION

[0079] Hereinafter, the scope of the present application will be described in more detail by way of examples, but the scope of the present application is not limited by the following examples.

Example 1

[0080] 208 g of TEOS (tetraethoxy silane) and 184 g of ethanol were mixed in a flask and stirred for about 10 minutes. Subsequently, an acidic solution prepared by mixing 2.4 g of hydrochloric acid and 72 g of water (H.sub.2O) was added in drops thereto to adjust the pH to about 1, and the mixture was stirred at room temperature for about 3 days to form a silica precursor composition. The silica precursor composition was applied on a glass substrate by a bar coating method to a thickness of about 10 m or so and dried at 80 C. for about 1 minute. After drying, the layer of the silica precursor composition was subjected to atmospheric pressure plasma treatment, and then immersed in trioctylamine (TOA) maintained at a temperature of 80 C. or so (pKa: 3.5, boiling point: about 366 C., flash point: about 163 C., room temperature vapor pressure: about 0.002 Pa) for about 5 minutes or so to form a silica film. The formed silica film was washed with flowing water at about 60 C. for about 2 minutes and dried in an oven at about 80 C. for 1 minute.

Example 2

[0081] 208 g of TEOS (tetraethoxy silane) and 184 g of ethanol were mixed in a flask and stirred for about 10 minutes. Subsequently, an acidic solution prepared by mixing 0.1 g of hydrochloric acid and 72 g of water (H.sub.2O) was added in drops thereto to adjust the pH to about 3, and the mixture was stirred at a temperature of 70 C. or so for about 3 days to form a silica precursor composition. Using the prepared silica precursor composition, a silica film was formed in the same manner as in Example 1.

Example 3

[0082] 208 g of TEOS (tetraethoxy silane) and 184 g of ethanol were mixed in a flask and stirred for about 10 minutes. Subsequently, an acidic solution prepared by mixing 19.6 g of sulfuric acid (H.sub.2SO.sub.4) and 36 g of water (H.sub.2O) was added in drops thereto to adjust the pH to about 1, and the mixture was stirred at room temperature for about 3 days to form a silica precursor composition. Using the prepared silica precursor composition, a silica film was formed in the same manner as in Example 1.

Example 4

[0083] 208 g of TEOS (tetraethoxy silane) and 184 g of ethanol were mixed in a flask and stirred for about 10 minutes. Subsequently, an acidic solution prepared by mixing 60 g of acetic acid (CH.sub.3COOH) and 72 g of water (H.sub.2O) was added in drops thereto to adjust the pH to about 3, and the mixture was stirred at room temperature for about 3 days to form a silica precursor composition. Using the prepared silica precursor composition, a silica film was formed in the same manner as in Example 1.

Example 5

[0084] 208 g of TEOS (tetraethoxy silane) and 240 g of isopropanol were mixed in a flask and stirred for about 10 minutes. Subsequently, an acidic solution prepared by mixing 2.4 g of hydrochloric acid and 72 g of water (H.sub.2O) was added in drops thereto to adjust the pH to about 1, and the mixture was stirred at room temperature for about 3 days to form a silica precursor composition. Using the prepared silica precursor composition, a silica film was formed in the same manner as in Example 1.

Example 6

[0085] 240 g of TEOS (tetraethoxy silane) and 138 g of ethanol were mixed in a flask and stirred for about 10 minutes. Subsequently, an acidic solution prepared by mixing 2.4 g of hydrochloric acid and 72 g of water (H.sub.2O) was added in drops thereto to adjust the pH to about 1, and the mixture was stirred at room temperature for about 3 days to form a silica precursor composition. Using the prepared silica precursor composition, a silica film was formed in the same manner as in Example 1.

Test Example 1

[0086] The surface hardness of the silica films of Examples 1 to 6 in the plane direction was confirmed by a steel wool test and the surface hardness in the thickness direction was confirmed by a pencil hardness test. The steel wool test was measured by rubbing the surface of the silica film ten times with a #0 steel wool at 25 C. and 50% relative humidity, and increasing the steel wool load in stages until the occurrence of defects such as scratches was confirmed on the surface of the silica film. The results of the steel wool test described in Table 1 below are loads that no defect of the silica film occurs.

[0087] The pencil hardness test was measured by a method of drawing a pencil lead over the surface of the sample at an angle of 45 degrees while applying a force of 1 kg at 25 C. and 50% relative humidity. It was measured by increasing the hardness of the pencil lead in stages until the occurrence of defects such as indentation, scratching or rupture was confirmed on the surface of the silica film. The result of the pencil hardness test, the pencil hardness that the above defects did not occur, was shown in Table 1 below.

TABLE-US-00001 TABLE 1 Steel Wool Test Pencil Hardness Test Example 1 1.5 Kg 9 H Example 2 1.5 Kg 9 H Example 3 1.2 Kg 9 H Example 4 1.0 Kg 8 H Example 5 1.3 Kg 9 H Example 6 800 g 7 H