PREPARATION METHOD OF SILICA LAYER

Abstract

Provided is a method for preparing a silica layer, comprising bringing to gelation a precursor layer formed from a precursor composition comprising a silica precursor an acid catalyst and a surfactant.

Claims

1. A method for preparing a silica layer comprising bringing to gelation a precursor layer formed from a precursor composition, wherein the precursor composition comprises a silica precursor, an acid catalyst and a surfactant.

2. The method according to claim 1, wherein the silica precursor is a silane compound of the following formula D or E, a hydrolysate of the silane compound or a condensation reaction product of the silane compound:
SiR.sup.1.sub.(4-n)(OR.sup.2).sub.n  [Formula D] wherein: R.sup.1 is hydrogen, an alkyl group, an alkenyl group, an aryl group, an arylalkyl group, an epoxy group, or a (meth)acryloyloxyalkyl group; R.sup.2 is an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a hydrogen atom; and n is 3 or 4, ##STR00015## wherein: L is a divalent linking group selected from the group consisting of an alkylene group and an arylene group, or a combination of two or more thereof; and R.sub.3 to R.sub.8 are each independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a hydrogen atom.

3. The method according to claim 1, wherein the precursor composition comprises a silica precursor in a ratio ranging from 5 to 60 wt %.

4. The method according to claim 1, wherein the precursor composition further comprises a solvent.

5. The method according to claim 4, wherein the solvent is a mixed solvent of an aqueous solvent and an organic solvent.

6. The method according to claim 1, wherein the surfactant forms micelles in the precursor layer or the precursor composition.

7. The method according to claim 1, wherein the precursor composition further comprises a solvent and the concentration of the surfactant is adjusted to be in a range of to 5 times the critical micelle concentration for the solvent.

8. The method according to claim 1, wherein the surfactant is a cationic surfactant, an anionic surfactant or a nonionic surfactant.

9. The method according to claim 1, wherein the gelation comprises contacting the precursor layer with an amine compound having a pKa of 8 or less.

10. The method according to claim 1, wherein the precursor composition further comprises a latent base generator and the gelation comprises generating a base from the latent base generator.

11. The method according to claim 10, wherein the latent base generator is a compound of the following formula 11 or is an ionic compound having a cationic compound of one of the following Formulas 13 to 15 or one which is contained in a compound of the following Formula 18 or derived therefrom: ##STR00016## wherein R.sub.9 is hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 12 carbon atoms; R.sub.11 and R.sub.12 are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms; and R.sub.10 is hydrogen, an alkyl group having 1 to 4 carbon atoms, an arylalkyl group having 7 to 16 carbon atoms or a substituent of the following formula 12: ##STR00017## wherein L.sub.1 is an alkylene group having 1 to 4 carbon atoms, ##STR00018## wherein R.sub.13 to R.sub.20 are each independently hydrogen or an alkyl group having 1 to 20 carbon atoms, ##STR00019## wherein R.sub.21 to R.sub.24 are each independently hydrogen or an alkyl group having 1 to 20 carbon atoms, ##STR00020## wherein R.sub.25 to R.sub.30 are each independently hydrogen or an alkyl group having 1 to 20 carbon atoms, ##STR00021## wherein R.sub.31 and R.sub.32 are each independently hydrogen, a linear or branched alkyl group having 1 to 4 carbon atoms or a cyclic alkyl group having 4 to 8 carbon atoms, or R.sub.31 and R.sub.32 are linked to each other to form a nitrogen-containing heterocyclic structure together with the nitrogen atom to which R.sub.31 and R.sub.32 are linked; Ar is an aryl group; and L.sub.2 is -L.sub.3-O— or an alkenyl group having 2 to 4 carbon atoms, wherein L.sub.3 is an alkylene group having 1 to 4 carbon atoms or an alkylidene group having 1 to 4 carbon atoms.

12. The method according to claim 1, further comprising removing the surfactant after the gelation process.

13. The method according to claim 12, wherein removal of the surfactant is performed using an alcohol solvent, a ketone solvent or an acetate solvent.

14. The method according to claim 1, wherein the gelation of the precursor layer proceeds on a base material.

15. The method according to claim 14, wherein the base material is any one functional layer selected from the group consisting of a high-refraction layer, a hard coating layer, an antireflection layer, a polarizing film, a protective film of a polarizing film, a luminance enhancement film, a retardation film, a display panel and a touch panel.

Description

MODE FOR INVENTION

[0187] 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.

[0188] 1. Steel Wool Test

[0189] The steel wool resistance was evaluated by rubbing the following formed silica layer with a steel wool while keeping it at a temperature of 25° C. and 50% relative humidity. In the evaluation process, the evaluation was progressed while gradually increasing the load until defects such as scratches were visually observed, and the load was described as the evaluation result. Here, as the steel wool, a steel wool of grade #0000 sold by Briwax of Europe was used.

[0190] 2. Evaluation of Reflectance

[0191] After laminating the formed silica layer on a PET (poly(ethylene terephthalate) film, the reflectance was evaluated based on light having a wavelength of 550 nm using a measuring instrument (spectrophotometer, Konica-Minolta, CM-2600D) at a temperature of 25° C. and 50% relative humidity.

Example 1

[0192] TEOS (tetraethoxy silane) was mixed with ethanol (EtOH) as a solvent and stirred for 10 minutes or so. Subsequently, the catalyst solution in which distilled water (H.sub.2O) and hydrochloric acid (HCl) were mixed was slowly dropped to the mixture over approximately 5 minutes and stirred. After dropping, the mixture was further stirred for approximately 18 hours without separate cooling or constant temperature maintenance. After stirring, the pH was at a level of approximately 2 to 5. Here, the ratio of the mixed components was approximately 36.14:92.14:104.17:3.65 (weight ratio: distilled water:TEOS:ethanol:hydrochloric acid) or so.

[0193] When the content of silica solids in the mixture is calculated assuming that the entire added TEOS is 100% reacted, it can be calculated to be about 11.25 wt % or so. The obtained mixture was mixed with CTAB (cetyl triammonium bromide, C16; Aldrich) as a surfactant at a ratio of 50 parts by weight relative to 100 parts by weight of the calculated solid content to obtain a precursor composition.

[0194] Thereafter, the precursor composition was applied on a glass base material to a thickness of approximately 1 μm or so by a bar coating method and dried in an oven at 80° C. or so for 1 minute or so to form a precursor layer.

[0195] The obtained precursor layer was immersed in trioctylamine (TOA) at about 80° C. for 5 minutes or so to form a silica layer having a thickness of about 120 nm. The formed silica layer was washed with running water at about 40° C. or so for 3 minutes or so and dried in an oven at 80° C. for 2 minutes or so, and then the reflectance (Reflectance 1 in Table 1 below) was measured, and for removing the residual surfactant, it was washed using 50° C. ethanol for 1 hour, and then the reflectance was measured again (Reflectance 2 in Table 1 below). The physical property evaluation results of the formed silica layer were summarized in Table 1 below.

Examples 2 to 11

[0196] A silica layer was produced in the same manner as in Example 1, except that the kind and ratio of the surfactant were controlled as shown in Table 1 below, and the results were also summarized in Table 1 below.

TABLE-US-00001 TABLE 1 Surfactant Reflectance 1 Reflectance 2 Steel wool Surfactant ratio (%, 550 nm basis) (%, 550 nm basis) test Example 1 CTAB 50 3.67 2.52 140 g Example 2 CTAB 75 3.57 2.31 100 g Example 3 CTAB 100 4.14 1.8  80 g Example 4 DTAB 50 2.11 2.17 100 g Example 5 DTAB 100 2.31 2.43 100 g Example 6 F127 50 — 2.97 120 g Example 7 F127 100 3.95 2.94 120 g Example 8 Tween80 50 3.68 3.59 — Example 9 Tween80 100 4.07 1.65  80 g Example 10 Brij98 50 3.77 1.79 100 g Example 11 Brij98 100 3.21 2.63 100 g Surfactant ratio parts by weight relative to 100 parts by weight of silica solid content CTAB: cetyl triammonium bromide (manufactured by Alrich) DTAB: decyl triammonium bromide (manufactured by Alrich) F127: PEO.sub.99PPO.sub.69PEO.sub.99, Mw = 12,500 (manufactured by BASF) Tween 80 (manufactured by Aldrich Surfactant: Mw = 1310), manufactured by Aldrich Brij 98 (manufactured by Aldrich Surfactant: Mw = 1150) PEO: poly(ethylene oxide) PPO: poly(propylene oxide) Mw: weight average molecular weight

Examples 12 to 20

[0197] A silica layer was produced in the same manner as in Example 1, except that the kind and ratio of the surfactant, the thickness of the silica layer and the cleaning conditions of the surfactant were controlled as shown in Table 1 below, and the results were summarized in Table 2 below.

TABLE-US-00002 TABLE 2 Surfactant Silica layer Surfactant cleaning Reflectance 2 Surfactant ratio thickness (nm) conditions (%, 550 nm basis) Example 12 F127 100 100 water, 80° C., 16 hours 3.66 Example 13 F127 100 140 ethanol, 55° C., 16 hours 0.95 Example 14 F127 100 120 ethanol, 55° C., 16 hours 1.07 Example 15 F127 100 100 ethanol, 55° C., 16 hours 1.52 Example 16 CTAB 100 140 ethanol, 55° C., 16 hours 1.70 Example 17 Brij98 100 140 ethanol, 55° C., 16 hours 1.87 Example 18 F127 100 140 acetone, 55° C., 16 hours 1.36 Example 19 F127 100 120 acetone, 55° C., 16 hours 1.40 Example 20 F127 100 100 acetone, 55° C., 16 hours 1.95 Surfactant ratio: parts by weight relative to 100 parts by weight of silica solid content CTAB: cetyl triammonium bromide (manufactured by Alrich) F127: PEO.sub.99PPO.sub.69PEO.sub.99, Mw = 12,500 (manufactured by BASF) Brij 98 (manufactured by Aldrich Surfactant: Mw = 1150) PEO: poly(ethylene oxide) PPO: poly(propylene oxide) Mw: weight average molecular weight Surfactant cleaning condition: applied solvent: holding temperature: cleaning time