KR102476238B1 - Synthetic procedure of titania nanosol, and fabrication process of high-refractive-index thin film based on titania nanosol - Google Patents

Abstract

The present invention relates to a method for manufacturing titania nano-sol and a method for manufacturing a high-refractive thin film based on titania nano-sol, and more particularly, to an optical material that can form a reticulated high-refractive hybrid thin film that is much stronger than the existing particle-type titania sol. and a method for easily preparing titania nano-sol, which is particularly suitable as a coating material for electrical/electronic products, at room temperature without a temperature increase or concentration process, and a method for manufacturing a high refractive index thin film using the thus prepared titania nano-sol.

Description

Synthetic procedure of titania nanosol, and fabrication process of high-refractive-index thin film based on titania nanosol}

The present invention relates to a method for manufacturing titania nano-sol and a method for manufacturing a high-refractive thin film based on titania nano-sol, and more particularly, to an optical material that can form a reticulated high-refractive hybrid thin film that is much stronger than the existing particle-type titania sol. and a method for easily preparing titania nano-sol, which is particularly suitable as a coating material for electrical/electronic products, at room temperature without a temperature increase or concentration process, and a method for manufacturing a high refractive index thin film using the thus prepared titania nano-sol.

In general, titania sol is a material having the best physical properties among metal-alkoxide-based sol such as high refractive index, chemical resistance, thermal stability, high permeability, structural specificity, dielectric properties, and mechanical properties.

Therefore, titania sol is in the limelight in the fields of optical materials, electric and electronic materials, and information and electronic materials requiring excellent properties, and research is being actively conducted to utilize titania sol as a material in these fields.

Currently, inorganic sol is mainly used for prism film or light diffusion film in liquid crystal displays (LCDs) used as major panels of mobile phones, laptop computers, TVs, and computers. Since the particle size and degree of dispersion directly affect the efficiency, size control and compatibility with organic solvents are also greatly required.

However, when implementing a sol in the form of particles, non-uniformity of the thin film occurs, the dispersion stability decreases, and cohesive force occurs between the particles, so the size and dispersibility of the particles are uniform in the form of monodisperse. There is a problem that is difficult to control. In addition, there is a problem in that light scattering occurs when particles having a size of 30 nm or more in a generally spherical shape are used. Furthermore, titania sol prepared by hydrothermal synthesis has been limited in application to optical materials, high dielectric materials, and electronic materials due to its low solid content and purity.

Korean Patent Registration No. 10-1468862 discloses (1) preparing a first titanium oxide sol by mixing a titanium compound and an alcohol, adding an acid and water, and performing a hydrothermal synthesis reaction; (2) preparing a second titanium oxide sol by mixing a titanium compound, water, and an organic solvent, heating, adding an acid, and carrying out a water-based synthesis reaction; and (3) mixing the first and second titanium oxide sol in a weight ratio of 1:1.

In addition, Korean Patent Registration No. 10-1172804 discloses a first step of preparing a colloidal chelating titania nanosol by adding and stirring a solvent after chelating a purified titanium precursor; a second step of replacing or concentrating the solvent contained in the titania nanosol of the first step; A third step of preparing a titania nanosol coating solution capable of being coated by adding functional silane, a silicone compound and a functional organic polymer to the titania nanosol of the second step and then stirring them; A fourth step of preparing a high refractive titania thin film by wet-coating the titania nano sol coating solution on an upper layer of a substrate and drying it.

However, since the above-described prior art requires many steps including temperature raising and concentration processes and requires a hydrothermal synthesis reaction requiring a high temperature, the process becomes complicated and the manufacturing cost increases.

Therefore, through modification of the surface of the particle, a technology that can improve thin film whitening, which is a disadvantage of titanium dioxide, suppresses the occurrence of scattering, and easily prepares titania nanosol with excellent permeability and coating properties at room temperature without a temperature increase or concentration process. development is required.

An object of the present invention is to prepare a titania nano-sol capable of forming a reticulated high-refractive hybrid thin film that is much stronger than the existing particle-type titania sol at room temperature without a temperature increase and concentration process, a method for preparing a titania nano-sol, and a method for manufacturing a high refractive index thin film using the thus prepared titania nanosol.

According to one aspect of the present invention, (1) hydrolyzing a titanium precursor dissolved in alcohol under non-elevated temperature conditions; and (2) adding an acid to the product of step (1) under non-elevated temperature conditions.

According to another aspect of the present invention, (i) hydrolyzing a titanium precursor dissolved in alcohol under non-elevated temperature conditions; (ii) adding an acid to the product of step (i) under non-elevated temperature conditions; (iii) mixing a silicone compound with the product of step (ii); and (iv) coating the product of step (iii) on the surface of the substrate and drying it.

According to the present invention, unlike the hydrothermal synthesis method used in existing inorganic nanosols, titania nanosols can be easily prepared at room temperature without a temperature increase and concentration process, and the titania nanosols according to the present invention have high dispersibility and transparency, It has good compatibility with photocurable organic materials and photocurable organic materials, and when used in combination with a silicon compound, it can form a solid network-type high refractive hybrid thin film, so it can be particularly useful as a coating material for optical materials and electric/electronic products.

1 shows refractive index data for each wavelength of thin films prepared according to Example 1 and Comparative Example 1 of the present invention, respectively.
2 shows transmittance data for each wavelength of thin films prepared according to Example 1 and Comparative Example 1 of the present invention, respectively.
3 is a scanning electron microscope (SEM) image of a thin film prepared according to Example 1 of the present invention.
4 is a scanning electron microscope (SEM) image of a thin film prepared according to Comparative Example 1 of the present invention.

Hereinafter, the present invention will be described in detail.

The method for producing titania nano-sol of the present invention includes (1) hydrolyzing a titanium precursor dissolved in alcohol under non-elevated temperature conditions; and (2) adding an acid to the product of step (1) under non-elevated temperature conditions.

The non-elevated temperature condition refers to a condition in which heating is not artificially performed, and more specifically, may be a temperature condition of room temperature or lower. Here, room temperature means 25±5° C., and temperature conditions below that mean 20° C. or less (eg, -10 to 20° C.).

The titanium precursor includes one or more (eg, 1 to 4) alkoxides (eg, 1 to 10 carbon atoms) or anionic groups (eg, halides, nitrides, borides, sulfates, sulfides, carbide, etc.) may be used. Specifically, the titanium precursor includes titanium (mono to tetra) methoxide, titanium (mono to tetra) ethoxide, titanium (mono to tetra) propoxide, titanium (mono to tetra) isopropoxide, titanium (mono to tetra) ethoxide, to tetra)butoxide, titanium isopropoxide bis(acetylacetonate), titanium (mono to tetra)(2-ethylhexyloxide), titanium chloride, titanium fluoride, titanium nitride, titanium boride, titanium sulfate , At least one selected from the group consisting of titanium oxysulfate, titanium sulfide, and titanium carbide may be used, and more specifically, at least one compound in which one or more alkoxy groups are bonded to titanium may be used.

As the alcohol, an alkanol having one or more (eg, 1 to 2) hydroxyl groups, glycol ether, glycol, or a combination thereof may be used.

Specifically, as the alkanol (eg, an alkanol having 1 to 10 carbon atoms), methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, butanol, hexanol, or a combination thereof may be used; Examples of the glycol ether include ethylene glycol monomethyl ether (ie, methyl cellosolve), ethylene glycol monoethyl ether (ie, ethyl cellosolve), ethylene glycol monopropyl ether (ie, propyl cellosolve), and ethylene glycol mono Butyl ether (ie, butyl cellosolve), ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether , propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, or a combination thereof may be used; Examples of the glycol (eg, di-, tri- or polyalkylene (eg, alkylene having 2 to 4 carbon atoms) glycol) include ethylene glycol, propylene glycol, butylene glycol, neopentylene glycol, diethylene glycol, and triethylene glycol , tetraethylene glycol, polyethylene glycol, propylene glycol alginate, propoxylated neopentyl glycol, or a combination thereof may be used, but is not limited thereto.

According to one embodiment of the present invention, the alcohol is methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, butanol, hexanol, methyl cellosolve, ethyl cellosolve, propyl cellosolve, butyl cell At least one selected from the group consisting of Rosolve, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol and polyethylene glycol may be used.

An inorganic acid or an organic acid may be used as the acid. Specifically, the acids include sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, iodic acid, hydrofluoric acid, chlorosulfonic acid, polyphosphoric acid, perchloric acid, formic acid, lactic acid, propionic acid, acetic acid, para-toluenesulfonic acid, chloroacetic acid and their anhydrides. One or more selected from the group consisting of may be used.

The titanium precursor may be used in an amount of preferably 5 to 100 parts by weight, more preferably 10 to 90 parts by weight, based on 100 parts by weight of the alcohol. If the amount of the titanium precursor is too small, problems may occur in terms of crystallinity and solid content of the precursor, and if the amount is too large, a rapid increase in viscosity may occur.

The acid may be used in an amount of preferably 1 to 30 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the alcohol.

In step (1) of the titania nanosol preparation method of the present invention, hydrolysis of the titanium precursor dissolved in alcohol may be performed by adding water (eg, distilled water) and stirring. The amount of water added at this time may be preferably 1 to 40 parts by weight, more preferably 5 to 30 parts by weight, based on 100 parts by weight of alcohol. The stirring may be performed at a rate of 200 to 600 rpm for, for example, 5 minutes to 2 hours, but is not limited thereto.

In step (2) of the titania nano-sol preparation method of the present invention, acid is added to the hydrolyzed mixture obtained in step (1). The acid used herein is as described above. After adding the acid, the resulting mixture may be stirred at a speed of 200 to 600 rpm for, for example, 12 to 36 hours, but is not limited thereto.

When the titania nanosol is prepared by the sol-gel reaction according to the present invention, the stability and coordination form of the titania sol can be controlled by controlling the reaction rate and imparting crystallinity.

A method for producing a high refractive index thin film provided according to another aspect of the present invention includes (i) hydrolyzing a titanium precursor dissolved in alcohol under non-elevated temperature conditions; (ii) adding an acid to the product of step (i) under non-elevated temperature conditions; (iii) mixing a silicone compound with the product of step (ii); and (iv) coating the product of step (iii) on the surface of the substrate and drying it.

Steps (i) and (ii) of the method of manufacturing a high refractive index thin film according to the present invention and the materials used therein are the same as those described in steps (1) and (2) of the method of preparing titania nanosol.

The silicon compound modifies the surface of the titania nanosol to form a hybrid thin film.

As the silicone compound, an alkoxysilane having at least one functional group selected from an acrylic group, a methacrylic group, an alkyl group, a hydroxyl group, a mercapto group, an isocyanate group, a ureido group, an aryl group, a vinyl group, an allyl group, an amine group, and an epoxy group. One or more compounds may be used, and more specifically, one selected from the group consisting of trialkoxysilane compounds, dialkoxysilane compounds, and combinations thereof having one or more functional groups may be used.

For example, as the silicone compound, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane , n-propyltrimethoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n -Pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, cyclohexyltrimethoxysilane, Cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxy Silane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2-hydroxyethyl Triethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyane Itopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclo Hexyl) ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane , 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxy Silane, di-n-propyldiethoxysilane, di-i-propyldimethoxysilane, di-i-propyldiethoxysilane, di-n-butyldimethoxysilane, di-n-butyldiethoxysilane, di-n -Pentyldimethoxysilane, di-n-pentyldiethoxysilane, di-n-hexyldimethoxysilane, di-n-heptyldimethoxysilane, di-n-heptyldiethoxysilane, di-n-octyldimethoxysilane , di-n-octyldiethoxysilane, di-n-cyclohexyldimethoxysilane, di-n-cyclohexyldie What is selected from the group consisting of toxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and combinations thereof may be used.

The silicon compound may be used in an amount of preferably 1 to 10 parts by weight, and more preferably 1 to 5 parts by weight, based on 100 parts by weight of the solid content of the titania nanosol, which is the product of step (ii). If the use amount of the silicon compound compared to the solid content of the titania nanosol is too small, there may be a problem of generating pinholes in the thin film.

The method and conditions for mixing the titania nano-sol and the silicon compound are not particularly limited, and may be performed by, for example, stirring at a speed of 200 to 600 rpm for 10 minutes to 4 hours under non-elevated temperature conditions, but is not limited thereto. not. In addition, when mixing the titania nanosol and the silicon compound, an organic solvent may be additionally used, and as such an organic solvent, one or more of alkanol, glycol ether, glycol, and the like described above may be used.

A mixture of titania nanosol and silicon compound may be coated on the surface of the substrate, preferably by a wet coating method. More specifically, the wet coating method may be selected from the group consisting of spin coating, bar coating, slot die coating, dip coating, spray coating, gravure coating, doctor blade coating, flow coating and roll-to-roll coating.

Hereinafter, the present invention will be described in more detail through examples, but this is only for explaining the present invention, and the scope of the present invention is not limited by the examples.

[Example]

Example 1

A titania nanosol was prepared by a sol-gel reaction. After putting 60 g of titanium tetrabutoxide (TTBO) in 100 g of isopropyl alcohol (IPA) in the reactor, the mixture was dissolved by stirring at 400 rpm for 10 minutes at room temperature (25 ° C). 20 ml of distilled water was slowly added thereto, and the resulting mixture was stirred at 400 rpm for 30 minutes to hydrolyze the titanium precursor. 15 g of acetic acid was added to the resulting mixture for 1 hour and stirred for 24 hours to prepare titania nanosol.

0.1 g of diphenyldimethoxysilane was added to the prepared titania nanosol (solid content: 25% by weight), and stirred at room temperature at 400 rpm for about 2 hours. The resulting mixture was wet-coated on a substrate and dried to prepare a high refractive index hybrid thin film.

For the prepared thin film, the refractive index and transmittance for each wavelength were measured using an ellipsometer (model name: Elli-SE, manufacturer: Ellipsotechnology) and a spectrometer (model name: CM-3700A, manufacturer: Konika Minolta), respectively, The results are shown in FIGS. 1 and 2, respectively. As a result of the measurement, it was confirmed that the thin film prepared in this example exhibited a high refractive index of 1.86 or more, particularly in the visible light region (550 nm or more).

In addition, the surface of the prepared thin film was photographed with a scanning electron microscope (SEM), and the image is shown in FIG. 3 . As can be seen from FIG. 3, no particle shape was found on the surface of the thin film prepared in this example.

Comparative Example 1

A titania nano-sol was prepared in the same manner as in Example 1, except that acetic acid was not added during the preparation of the titania nano-sol, and a thin film was manufactured in the same manner as in Example 1 using the titania nano-sol.

For the prepared thin film, the refractive index and transmittance for each wavelength were measured in the same manner as in Example 1, and the results are shown in FIGS. 1 and 2, respectively. . As a result of the measurement, it was confirmed that the refractive index and transmittance of the thin film prepared in this comparative example were significantly lower than those of Example 1.

In addition, the surface of the prepared thin film was photographed with a scanning electron microscope (SEM), and the image is shown in FIG. 4 . As can be seen from FIG. 4, unlike Example 1, many particle shapes were found on the surface of the thin film prepared in this comparative example.

Example 2

A titania nanosol was prepared in the same manner as in Example 1, except that 60 g of titanium tetraisopropoxide was used as the titanium precursor and 10 g of hydrochloric acid was used as the acid. manufactured.

As a result of measuring the refractive index and transmittance for each wavelength in the same manner as in Example 1 for the prepared thin film, refractive index and transmittance equivalent to those of the thin film of Example 1 were confirmed.

Claims (18)

(1) hydrolyzing the titanium precursor dissolved in isopropyl alcohol under non-elevated temperature conditions; and
(2) adding acetic acid to the product of step (1) under non-elevated temperature conditions,
Manufacturing method of titania nano sol. The method for preparing a titania nanosol according to claim 1, wherein the titanium precursor is a compound in which one or more alkoxides or anionic groups are bonded to titanium. The method of claim 1, wherein the titanium precursor is titanium (mono to tetra) methoxide, titanium (mono to tetra) ethoxide, titanium (mono to tetra) propoxide, titanium (mono to tetra) isopropoxide, titanium ( Mono to tetra)butoxide, titanium isopropoxide bis(acetylacetonate), titanium (mono to tetra)(2-ethylhexyloxide), titanium chloride, titanium fluoride, titanium nitride, titanium boride, titanium alcohol A method for producing a titania nano sol, which is at least one selected from the group consisting of pate, titanium oxysulfate, titanium sulfide and titanium carbide. The method of claim 1, wherein, in step (1), water is added to the titanium precursor dissolved in isopropyl alcohol, and the resulting product is stirred at a speed of 200 to 600 rpm for 5 minutes to 2 hours. The method of claim 1, wherein in step (2), after adding acetic acid, the resulting mixture is stirred at a speed of 200 to 600 rpm for 12 to 36 hours. (i) hydrolyzing the titanium precursor dissolved in isopropyl alcohol under non-elevated temperature conditions;
(ii) adding acetic acid to the product of step (i) under non-elevated temperature conditions;
(iii) mixing a silicone compound with the product of step (ii); and
(iv) coating the product of step (iii) on the surface of the substrate and drying it;
Manufacturing method of high refractive index thin film. The method of claim 6, wherein the titanium precursor is a compound in which one or more alkoxides or anionic groups are bonded to titanium. The method of claim 6, wherein the titanium precursor is titanium (mono to tetra) methoxide, titanium (mono to tetra) ethoxide, titanium (mono to tetra) propoxide, titanium (mono to tetra) isopropoxide, titanium ( Mono to tetra)butoxide, titanium isopropoxide bis(acetylacetonate), titanium (mono to tetra)(2-ethylhexyloxide), titanium chloride, titanium fluoride, titanium nitride, titanium boride, titanium alcohol At least one selected from the group consisting of pate, titanium oxysulfate, titanium sulfide and titanium carbide, a method for producing a high refractive index thin film. The method of claim 6, wherein the silicone compound is at least one functional group selected from an acrylic group, a methacrylic group, an alkyl group, a hydroxyl group, a mercapto group, an isocyanate group, a ureido group, an aryl group, a vinyl group, an allyl group, an amine group, and an epoxy group. A method for producing a high refractive thin film having an alkoxysilane compound. The method of claim 6, wherein, in step (i), water is added to the titanium precursor dissolved in isopropyl alcohol, and the resulting product is stirred at a speed of 200 to 600 rpm for 5 minutes to 2 hours. The method of claim 6, wherein in step (ii), after adding acetic acid, the resulting mixture is stirred at a rate of 200 to 600 rpm for 12 to 36 hours. The method of claim 6, wherein in step (iv), the product of step (iii) is coated on the surface of the substrate by a wet coating method. delete delete delete delete delete delete

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