Titania sol, method of preparing the same, and coating composition comprising the same

Abstract

The present invention relates to a titania sol, a method of preparing the same, and a coating composition including the same. More specifically, it relates to a titania sol prepared by elevating the temperature of a reactant solution including a precursor of titania in a solvent for a reaction temperature, adding an acid catalyst to the reactant solution and conducting a sol-gel reaction while removing the solvent for reaction therefrom, and drying the prepared titania sol and re-dispersing the dried titania in a solvent for dispersion, a method of preparing the same, and a coating composition including the same.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein:

FIG. 1 is a transmission electron microscope (TEM) photograph showing titania particles prepare by Example 1.

FIG. 2 is a TEM photograph showing titania particles prepared by Example 2.

FIG. 3 is a TEM photograph showing titania particles prepared by Example 3.

FIG. 4 is a TEM photograph showing titania particles prepared by Example 4.

FIG. 5 is an X-ray diffraction graph showing a crystal form of titania prepared by Example 1.

FIG. 6 is a graph showing a distribution of re-dispersed titania sol prepared by Example 1.

FIG. 7 is a graph showing a distribution of re-dispersed titania sol prepared by Comparative Example 6.

Claims

1. A method of preparing a titania sol, comprising the steps of: a) elevating the temperature of a reactant solution comprising a precursor of titania in a solvent for reaction to a reaction temperature;b) preparing a titania sol by adding an acid catalyst to the reactant solution and conducting a sol-gel reaction while removing the solvent for reaction therefrom; andc) drying the prepared titania sol and re-dispersing the dried titania in a solvent for dispersion.

2. The method according to claim 1, wherein the sol-gel reaction while removing the solvent for reaction of step b) is conducted at a temperature of from 70 to 95° C.

3. The method according to claim 1, wherein the drying of step c) is conducted at a temperature of 95° C. or less.

4. The method according to claim 3, wherein the drying of step c) is conducted by a method of freeze drying, normal pressure drying, or vacuum drying.

5. The method according to claim 1, wherein the removing of the solvent for reaction is conducted to eliminate an evaporated solvent from the reactor.

6. The method according to claim 1, wherein the removing of the solvent for reaction is conducted under decompression.

7. The method according to claim 1, wherein the solvent for reaction and the solvent for dispersion are the same or different one or more solvents selected from the group consisting of water, a lower alcohol of C1-C5, a higher alcohol of C6 or more, hexylene glycol, and acetyl acetone.

8. The method according to claim 7, wherein the lower alcohol is methanol, ethanol, propanol, isopropyl alcohol, butyl alcohol, or isobutyl alcohol, and the higher alcohol is a polyvinyl alcohol.

9. The method according to claim 1, wherein the precursor of titania is one or more compounds selected from the group consisting of tetraethoxy titanium, tetraisopropoxy titanium, tetrabutoxy titanium, titanyl chloride, titanyl sulfate, and titanyl oxysulfate.

10. The method according to claim 1, wherein the acid catalyst is one or more compounds selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid, and acetic acid.

11. The method according to claim 1, wherein the acid catalyst is added in an amount of from 11 to 30 parts by weight based on 100 parts by weight of the precursor of titania.

12. The method according to claim 1, wherein one or more inorganic salts selected from the group consisting of NaCl, KCl, NaBr, and KBr, or one or more surfactants selected from the group consisting of sodium dodecyl sulphate, cetyltrimethyl ammonium bromide, and cetyltrimethyl ammonium chloride, is added to the reactant solution in step a).

13. The method according to claim 12, wherein the inorganic salt or the surfactant is added in an amount of from 1 to 10 parts by weight based on 100 parts by weight of the precursor of titania.

14. A titania sol prepared by the method according to claim 1, and comprising secondary titania particles having an average diameter of 200 nm or less.

15. The titania sol according to claim 14, wherein the secondary titania particles comprise two or more primary titania particles having an average diameter of 1 to 20 nm.

16. The titania sol according to claim 15, wherein the primary titania particles are in an anatase crystal form or a rutile crystal form.

17. The titania sol according to claim 14, wherein the titania sol has a solid content of from 8 to 50 wt %.

18. The titania sol according to claim 14, wherein the standard deviation of the diameter of the secondary titania particle does not exceed 0.3.

19. A coating composition for a middle and high refractive coating layer, comprising the titania sol according to claim 14 in an amount of from 10 to 70 wt %.

20. The coating composition according to claims 19, wherein the middle and high refractive coating layer is applied for glasses, industrial safety glasses, or goggles for leisure.