KR20150072264A - Manufacturing method of high refractive titania sol having excellent dispersibility - Google Patents

Abstract

The present invention relates to a titania sol preparation method using a hydrothermal synthesis reaction and a water-based synthesis reaction. More specifically, the present invention relates to a method preparing a titania sol which includes titanium dioxide nanoparticles, having excellent dispersion performance, high transparency and a high refractive index, and to a high refractive titania sol prepared by the method.

Description

TECHNICAL FIELD [0001] The present invention relates to a high refractive index titania sol having excellent dispersibility,

The present invention relates to a method for producing titania sol using a hydrothermal synthesis reaction and an aqueous synthetic reaction, and more particularly, to a method for producing a high-refractive titania sol having excellent dispersibility and high transparency and containing titanium oxide nanoparticles, To a high-refraction titania sol prepared by the method.

Since a liquid crystal display (LCD), which is generally used as a main component of a TV, a desktop computer, a notebook computer, a mobile phone, etc., can not emit light by itself, a separate light source is provided on the back surface of the device, And the contrast is realized by controlling the intensity of the passing light through the liquid crystal. More specifically, a liquid crystal display device is a device that adjusts the transmittance of light using the electrical characteristics of a liquid crystal material, and transmits light emitted from a light source lamp on the back of the device to various functional prism films or sheets to adjust the uniformity and directionality And then pass it through a color filter to implement colors of red, green, and blue (R, G, B). Further, it is an indirect light emitting display device that controls the contrast of each pixel by an electric method to realize an image. A light emitting device for providing a light source in a liquid crystal display device is an important part for determining image quality such as brightness and uniformity of a liquid crystal display device.

A backlight unit (BLU) is widely used as the light emitting device. The backlight unit sequentially emits light emitted from a light source such as a cold cathode fluorescent lamp (CCFL) to a light guide plate, a light diffusion film, To reach the liquid crystal panel. Here, the light guide plate transmits the light emitted from the light source in such a manner as to be distributed over the entire surface of the liquid crystal panel having a planar shape, and the light diffusion film can obtain a uniform light intensity over the entire screen. The prism film performs a light path control function that converts light rays in various directions through the light diffusion film into a viewing angle range suitable for an observer to recognize an image. Also, since a reflective film is provided on the lower portion of the light guide plate, the light can not be transmitted to the liquid crystal panel, and the light that is out of the path can be reflected and utilized.

When producing such an optical film, an inorganic sol is generally used, and titania sol is typically used. Titania (titanium oxide, TiO ₂ ) itself is physically and chemically stable, has a refractive index of 2.5 or more, and is larger than a diamond having the highest refractive index among natural materials. If the refractive index is large, the amount of light emitted from the medium having a low refractive index in the optical material increases, and thus the thickness of the optical film can be reduced. When the high-refractivity titania particles are dispersed in the polymer medium, whiteness increases due to light scattering. Due to the high refractive index properties of titania, it is one of the important industrial materials that has been used as a white pigment for a long time. In addition, because of its high dielectric constant, it also occupies an important position as a raw material for piezoelectric materials, dielectrics, and semiconductor materials as the electronics industry develops. In recent years, applications of cosmetics, thin films, packaging materials, paints, lubricants and precision ceramics using ultraviolet barrier property and absorbency as a catalyst for removing organic contaminants due to chemical corrosion resistance and photocatalytic effect are rapidly expanding have. For example, Korean Patent Registration No. 10-062762, Korean Patent Registration No. 10-0523451 and Korean Patent Laid-open No. 10-2009-0080644 disclose such a preparation method for titania sol and its use. .

Titania has three mineral types: anatase, rutile and brookite. Among these three types of crystals, brookite is not a crystalline form that exists under ordinary conditions, and industrially, It is not important. As for the crystal structure of rutile and anatase, which are industrially important in correspondence with each use, both of the anatase and rutile crystal forms are classified into octahedra (TiO ₆ ^{2 -} And has a tetragonal structure occupying the corners, resulting in stoichiometry TiO ₂ . However, in the rutile type, two opposing corners of each octahedron occupy each other and form a linear chain along the (001) direction, and each chain is connected to each other by occupying oxygen atoms in the corners. Anatase, on the other hand, does not occupy a corner, but has four occupied corners per octahedron.

On the other hand, when an inorganic sol is produced through hydrolysis in the production of an inorganic sol, the size of the inorganic sol is increased, which may cause compatibility with the resin. In addition, light scattering phenomenon may occur, which may cause problems in the use of optical components such as optical films and displays.

Therefore, in order to actually apply the titania sol to an optical component, it is required that the average diameter size of the titanium oxide particles contained in the titania sol is preferably 10 nm or less. In other words, the particle size is small and the particle dispersibility in the organic solvent is excellent, but unlike general titania (titanium oxide), it has transparency without clouding phenomenon (increase in whiteness) and light scattering phenomenon, Development of high-refraction inorganic sols that can be used as a coating solution for films and various displays is required.

In addition, the conventional titanium dioxide sol has a problem that peeling of the coating film formed upon heat treatment after coating on the glass for display has occurred, so that the high-refractive titania sol having durability capable of maintaining a uniform coating film for a long time while preventing peeling- And the like.

Under these circumstances, the present inventors have found that by conducting a hydrothermal synthesis reaction and an aqueous synthesis reaction under specific reaction conditions in the production of titania sol, fine titanium nanoparticles are well dispersed, have high transparency, have a high refractive index, It is possible to produce titania sol which can be controlled to be controlled. Furthermore, it was confirmed that the durability of the coating film was excellent when the coating film was formed on the optical component using the titania sol. The present invention is based on this finding.

A first aspect of the present invention is a method for producing a titanium compound, comprising: a first step of mixing a titanium compound and an alcohol; A second step of preparing a first titanium oxide sol by a hydrothermal synthesis reaction by adding an acid and water to the mixed solution of the first step; A third step of mixing a titanium compound, water and an organic solvent; A fourth step of warming the mixed solution of the third step, adding an acid and a cellulose derivative to prepare a second titanium oxide sol in an aqueous synthetic reaction; And a fifth step of mixing the first titanium oxide sol and the second titanium oxide sol.

A second aspect of the present invention is to provide a titania sol produced by the manufacturing method according to the first aspect and containing titanium oxide nanoparticles having an average diameter of 5 nm to 30 nm.

A third aspect of the present invention is to provide an optical component which is molded or coated with the titania sol of the second aspect.

Hereinafter, the present invention will be described in detail.

The method for producing titania sol according to the present invention can provide a titania sol having a small particle size and excellent dispersibility.

On the other hand, for application to various optical components, it is preferable that titanium oxide crystals of a turbid type are formed at a high ratio. The present invention can provide a titania sol having improved anatase crystallinity by performing a hydrothermal synthesis reaction under a specific high temperature and high pressure condition have. In addition, the present invention can provide a titania sol having superior dispersity and transparency by preparing not only a titanium oxide sol by a hydrothermal synthesis reaction, but also a separate titanium oxide sol by an aqueous synthetic reaction and mixing them. Further, the present invention can further improve the durability of the coating film when the titania sol thus produced forms a coating film on an optical component by further adding a cellulose derivative in the aqueous synthetic reaction.

The titania sol prepared by the method of the present invention has a high refractive index and can control the refractive index value by controlling the content of titanium oxide in the sol.

In the present invention, the first step is a step of mixing a titanium compound and an alcohol, wherein the titanium compound is added to an alcohol as a polar solvent and mixed to prepare a mixed solution.

In the first step, the alcohol may be mixed in an amount of 10 to 100 parts by weight based on 1 part by weight of the titanium compound, but is not particularly limited.

The titanium compound is a compound containing a titanium (Ti) atom in a molecule and specifically includes a compound selected from the group consisting of titanium tetraisopropoxide, titanium chloride, titanium nitrate, titanium sulfate, titanium amino oxalate, But is not particularly limited to. Further, the titanium compound according to the first step may undergo hydrolysis with water before the first step, but this is not an optional step.

The alcohol used as a polar solvent in the hydrothermal synthesis reaction may be selected from the group consisting of ethyl alcohol, methyl alcohol, propyl alcohol, isopropyl alcohol, butanol, and mixtures thereof, but is not particularly limited.

The second step is a step of preparing a first titanium oxide sol by a hydrothermal synthesis reaction by adding an acid and water to the mixed solution of the first step. In the first step, a mixed solution of a titanium compound and an alcohol is mixed with an acid and water To obtain a titanium oxide hydrate sol. The titanium oxide hydrate sol thus obtained is heat-treated to conduct the hydrothermal synthesis reaction, whereby the first titanium oxide sol containing titanium oxide can be produced.

The hydrothermal synthesis reaction is carried out in the presence of water at high temperature and high pressure, whereby crystals of anatase-type titanium oxide can be formed at a high ratio. Specifically, the hydrothermal synthesis reaction may be carried out at 150 to 200 ° C and 10 to 20 atm for 2 to 3 hours. When the temperature and the pressure are lower than the above range, the hydrothermal synthesis reaction may not take place, and when the temperature and the pressure are higher than the above range, the risk of the reaction may increase.

In the second step, an acid and water may be added to the mixed solution in an amount of 0.01 to 1 part by weight based on 1 part by weight of the titanium compound in the mixed solution of the first step. Further, the water may be added and mixed in a predetermined weight range for improving the coating properties of the first titanium oxide sol and the titania sol to be produced. Specifically, the water may be added in an amount of 2 to 20 wt% based on the weight of the alcohol have. If the amount of water to be added deviates from the upper limit to the lower limit of the above range, the dispersibility of the first titanium oxide sol and the finally prepared titania sol produced through the second step may deteriorate, which is not preferable.

The acid is used as a catalyst for the hydrothermal synthesis reaction, and non-limiting examples thereof include organic acids such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid or citric acid fumaric acid; Or inorganic acids such as phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, chlorosulfonic acid, para-toluenesulfonic acid, trichloric acid, polyphosphoric acid, iodic acid, iodic acid anhydride or perchloric acid. And preferably an inorganic acid selected from the group consisting of nitric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid, and mixtures thereof.

In the present invention, the hydrothermal synthesis reaction in the second step can be performed at a high temperature and a high pressure using a hydrothermal synthesis reactor, and an example of the hydrothermal synthesis reactor that can be used for the hydrothermal synthesis reaction is shown in FIG.

FIG. 1 is a schematic view of the hydrothermal synthesis reactor of the present invention. The reactor may be equipped with a thermometer 1 and a pressure gauge 2, and may have a jacket 3 on the outside thereof.

The hydrothermal synthesis reactor which can be used in the present invention may be made of stainless steel so as to withstand a maximum temperature of 500 ° C. and a maximum pressure of 25 atm, and the capacity may be 5 L. Also, the agitator 4 having a rotation speed of 1,400 rpm may be provided to prevent precipitation during crystal growth and uniform growth.

In the hydrothermal synthesis reaction, a thermometer 1 including a temperature sensor may be provided in the reactor in order to prevent a rapid temperature rise that may occur during the temperature raising process and to control the temperature accurately. In the hydrothermal synthesis reaction, Can be performed by programming the sol synthesis.

The third step is a step of mixing a titanium compound, water, and an organic solvent. In addition to the first and second steps, a titanium compound is added to water and an organic solvent to prepare a mixed solution.

In the third step, 1 to 30 parts by weight of water and 0.01 to 2 parts by weight of an organic solvent may be mixed with respect to 1 part by weight of the titanium compound, but it is not particularly limited.

The titanium compound is the same as the description of the titanium compound in the first step. However, it is not necessary to necessarily use the same compound as the titanium compound of the first step, and it may be selected from the group consisting of titanium tetraisopropoxide, titanium chloride, titanium nitrate, titanium sulfate, titanium amino oxalate, have. Further, the amount of the titanium compound used in the third step need not be the same as the amount of the titanium compound in the first step, and the amount of the titanium oxide compound having the titanium oxide content different from that of the titanium oxide Titanium oxide sol can be produced.

The organic solvent may be selected from the group consisting of ethyl alcohol, methyl alcohol, propyl alcohol, isopropyl alcohol, butanol, ethylene glycol, butyl cellosolve, ethyl cellosolve, methyl cellosolve, , And is not particularly limited. Further, the organic solvent may be 3 to 10% by weight based on the weight of water to be added together.

The fourth step is a step of heating the mixed solution of the third step and then adding an acid and a cellulose derivative to prepare a second titanium oxide sol by an aqueous synthesis reaction. In the third step, the titanium compound, water and organic The second titanium oxide sol containing titanium oxide can be prepared by heating the mixed solution of the solvent and then additionally adding an acid and a cellulose derivative thereto to carry out an aqueous synthetic reaction. The titanium oxide sol produced through the first and second steps may have relatively poor transparency and dispersibility of the sol. However, it is possible to improve transparency and particle dispersibility of the final titania sol by mixing with the second titanium oxide sol which is further prepared through the third and fourth steps.

In the fourth step, the heating of the mixed solution in the third step may be performed until the temperature of the solution reaches 80 to 90 ° C, but is not particularly limited.

After heating the mixed solution, an aqueous synthetic reaction can be carried out together with addition of an acid and a cellulose derivative. Specifically, the aqueous synthetic reaction can be carried out at 80 to 100 ° C for 1 to 3 hours, no.

After the aqueous synthesis reaction in the fourth step, a step of spontaneous cooling with stirring for 8 to 16 hours may be further performed.

In the fourth step, 0.01 to 1 part by weight of an acid and 0.01 to 2 parts by weight of a cellulose derivative may be added to the mixed solution based on 1 part by weight of the titanium compound in the mixed solution of the third step.

The acid is used as a catalyst for an aqueous synthesis reaction, and examples thereof include organic acids such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid and citric acid fumaric acid; Or inorganic acids such as phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, chlorosulfonic acid, para-toluenesulfonic acid, trichloric acid, polyphosphoric acid, iodic acid, iodic acid anhydride or perchloric acid. And preferably an inorganic acid selected from the group consisting of nitric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid, and mixtures thereof. Furthermore, the acid in the fourth step need not necessarily be the same as the acid in the second step, and may be selected from the above-exemplified acids or a mixture of the selected acids, and is not particularly limited.

The cellulose derivative is added to improve the durability of the coating film when the titania sol produced by the method according to the present invention forms a coating film on the optical component. The cellulose derivative can be incorporated in various compositions as a constituent component to perform the function of imparting the viscosity of the entire composition. Therefore, in the present invention, it is possible to improve the durability and peel prevention of the coating film by increasing the viscosity and adhesion of the titania sol. . Specifically, the cellulose derivative may be at least one selected from the group consisting of hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), carboxymethylhydroxyethyl cellulose cellulose (CMHEC), hydroxypropylhydroxyethyl cellulose (HPHEC), methyl cellulose (MC), methylhydroxypropyl cellulose (MHPC), methylhydroxyethylcellulose selected from the group consisting of methylhydroxyethyl cellulose (MHEC), carboxymethylmethyl cellulose (CMMC), hydrophobically modified carboxymethyl cellulose (HMCMC), ethyl cellulose and mixtures thereof And preferably Hydroxy may be a hydroxypropyl cellulose (HPC), it is not particularly limited.

The fifth step is a step of mixing the first titanium oxide sol and the second titanium oxide sol, wherein the first titanium oxide sol prepared through the first and second steps and the third and fourth steps By mixing the prepared second titanium oxide sol, a high-refraction titania sol having excellent dispersibility can be produced.

As described above, a titania sol having improved transparency and dispersibility can be prepared by mixing the first titanium oxide sol and the second titanium oxide sol.

In the fifth step, the mixing weight ratio of the first titanium oxide sol and the second titanium oxide sol may be 3: 7 to 7: 3, but is not particularly limited.

As used herein, the terms "titania" to "titanium oxide" refer to oxidized titanium and its crystals stoichiometrically represented as TiO ₂ , which represent substantially the same material. However, in order to avoid confusion of the objects to be referred to in the present specification, the terms of the two are used differently, and they do not mean completely different materials.

A second aspect of the present invention provides a titania sol prepared by the manufacturing method according to the first aspect, which contains titanium oxide nanoparticles having an average diameter of 5 nm to 30 nm.

In the titania sol described above, the structure and features of the specific invention are as described in the first embodiment.

The titania sol is prepared using the hydrothermal synthesis reaction and the aqueous synthesis reaction according to the first embodiment, whereby fine titanium oxide nanoparticles (average diameter: 5 nm to 30 nm) containing a high proportion of inlaid crystal are contained in the sol It is dispersed in acid.

Furthermore, the titania sol contains the cellulose derivative used in the production method according to the first aspect of the present invention, thereby improving the viscosity and adhesion of the titania sol. Therefore, it is possible to improve the durability of the coating film when the coating film is formed using the titania sol, Peeling prevention is possible.

The titanium oxide content of the titania sol may be 0.5 to 5% by weight based on the total weight of the titania sol, but is not particularly limited. Further, the content of the cellulose derivative of the titania sol may be 0.5 to 2% by weight based on the weight of the titanium oxide, but is not particularly limited.

The titania sol is characterized by being a high-refractive titania sol having a refractive index of 1.3 or more.

In one embodiment of the present invention, the titania sol according to the present invention shows that the refractive index increases proportionally with an increase in the content of titanium oxide. Therefore, by controlling the titanium oxide content, The refractive index can be easily applied (Experimental Example 2 and Fig. 5).

The third aspect of the present invention provides an optical component molded or coated with the titania sol of the second aspect.

The titania sol according to the present invention can be effectively coated and supported on an optical component and an electronic component substrate. That is, the titania sol can be used for an optical material such as a high-refraction optical film for an LCD and an electronic material such as a high dielectric transparent insulating film for a thin film transistor.

The optical component may be an optical film for LCD, an optical film for LED, or an optical glass, but is not particularly limited.

The process for preparing titania sol using the hydrothermal synthesis reaction and the aqueous synthesis reaction according to the present invention can provide titania sol having small titanium oxide particles and high dispersibility. Furthermore, the titania sol has excellent transparency and refractive index, and the refractive index can be easily controlled by adjusting the titanium oxide content. Also, it has good coating property and excellent durability and peeling prevention function at the time of forming a coating film, so that it can be used and applied to various optical materials and electronic materials fields.

1 is a schematic diagram showing an example of a hydrothermal synthesis reactor that can be used in a hydrothermal synthesis reaction in a production method according to an embodiment of the present invention.
2 is a photograph showing a TEM analysis result of a transparent titania sol prepared according to an embodiment of the present invention.
FIG. 3 is a photograph showing FE-SEM analysis results of a transparent titania sol produced according to an embodiment of the present invention.
4 is a photograph showing the FE-SEM analysis result of the inorganic sol according to Comparative Example 1. Fig.
FIG. 5 is a graph showing a refractive index measurement result according to a solid content (titanium oxide) content of a transparent titania sol prepared according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to examples. These examples are for further illustrating the present invention, and the scope of the present invention is not limited by these examples.

Manufacturing example  1: Preparation of first titanium oxide sol using hydrothermal synthesis reaction

3 L of 95% ethyl alcohol and 100 g of titanium tetraisopropoxide (TTIP) were mixed and stirred, and the mixture was introduced into a hydrothermal synthesis reactor. After 63 g of pure water and 19 g of HNO ₃ (67%) were added thereto, the rotational speed of the stirrer was fixed at 1,000 rpm and the temperature condition was set as follows.

The mixture was heated at a temperature of 150 DEG C for 1 hour, subjected to a hydrothermal synthesis reaction at 150 DEG C for 2 hours, and then cooled to room temperature. Thereby, about 1% of white titanium oxide dispersion sol (first titanium oxide sol) was obtained through the outlet of the reactor. At this time, in the hydrothermal synthesis reaction, the pressure in the vessel applied at a temperature of 150 ° C was confirmed to be 10 to 15 atm.

Manufacturing example  2: Preparation of second titanium oxide sol using aqueous synthetic reaction

To synthesize aqueous sol, 1 kg of pure water, 177.65 g of TTIP and 65 g of acetyl acetone were added to a 5 L reactor and stirred for 30 minutes while controlling the temperature through a heating mantle and a hot plate at 90 ° C Lt; / RTI > After holding for 2 hours at 90 ℃, the addition of HNO _3, and 9.8g were stirred for 2 hours. Subsequently, 18 g of HPC (Hydroxypropyl cellulose) was added, followed by natural cooling with stirring for 12 hours to obtain an off-white aqueous sol (second titanium oxide sol).

Example  1: transparent Titania  Manufacture of Sol

The white primary titanium oxide sol and the off-white secondary titanium oxide sol obtained according to Production Example 1 and Production Example 2 were mixed at a weight ratio of 50:50. The color of the mixed sol changed transparently, thereby obtaining a transparent titania sol.

A TEM photograph of the obtained transparent titania sol was taken and is shown in FIG. As shown in FIG. 2, it was confirmed that the titania sol prepared by the method of the present invention had fine titanium oxide particles having a diameter of 10 nm or less on average.

Comparative Example  1: commercially available inorganic sol

A transparent inorganic sol (titania sol) having a particle size average diameter of 30 nm of degussa, which is currently commercially available, was purchased and set to Comparative Example 1.

Experimental Example  One: FE - SEM Particle comparison experiment using

The transparent titania sol obtained according to Example 1 and the inorganic sol according to Comparative Example 1 were photographed by FE-SEM and the results are shown in Fig. 3 (Example 1) and Fig. 4 (Comparative Example 1) Respectively.

As shown in FIG. 3 and FIG. 4, it was confirmed that the particles of the transparent titania sol according to Example 1 were smaller and finer than the particles of the inorganic sol of Comparative Example 1.

Experimental Example  2: Experiment of refractive index measurement

The refractive index of the transparent titania sol obtained according to Example 1 was measured according to the solid content (titanium oxide content).

Specifically, after spin-coating the transparent titania sol according to Example 1 on a silicon wafer, the refractive index was measured at an incident angle of light of 70 및 and a wavelength of 587.6 nm using a spectroscopic ellipsometer Respectively. The measurement of the refractive index was repeatedly performed with different amounts of titanium oxide, and the results are shown in FIG.

As shown in FIG. 5, it was confirmed that the titania sol according to the present invention has a higher refractive index as the solid content (titanium oxide content) is higher. Further, it has been confirmed that by controlling the content of titanium oxide in the sol, it can be easily controlled to have a desired refractive index. Also, even if the titanium oxide content was less than 1 wt%, the refractive index was 1.3 or more, and it was confirmed that the titania sol according to the present invention had a high refractive index.

From the above experiments, it can be seen that the high-refractive-index titania sol of the present invention using the hydrothermal synthesis reaction and the aqueous synthesis reaction is excellent in crystallinity, size and dispersibility of titanium oxide particles and can be effectively coated and supported on an optical substrate, It can be demonstrated. As a result, it was confirmed that the present invention meets the object of the present invention.

1: thermometer 2: pressure gauge
3: jacket 4: stirrer

Claims (12)

A first step of mixing a titanium compound and an alcohol;
A second step of preparing a first titanium oxide sol by a hydrothermal synthesis reaction by adding an acid and water to the mixed solution of the first step;
A third step of mixing a titanium compound, water and an organic solvent;
A fourth step of warming the mixed solution of the third step, adding an acid and a cellulose derivative to prepare a second titanium oxide sol in an aqueous synthetic reaction; And
And a fifth step of mixing the first titanium oxide sol and the second titanium oxide sol.
The method according to claim 1, wherein the titanium compound is selected from the group consisting of titanium tetraisopropoxide, titanium chloride, titanium nitrate, titanium sulfate, titanium aminoxalate, and mixtures thereof.
The method for producing a titania sol according to claim 1, wherein the alcohol is selected from the group consisting of ethyl alcohol, methyl alcohol, propyl alcohol, isopropyl alcohol, butanol, and mixtures thereof.
The method of claim 1, wherein the acid is selected from the group consisting of nitric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid, and mixtures thereof.
The method according to claim 1, wherein the organic solvent is selected from the group consisting of ethyl alcohol, methyl alcohol, propyl alcohol, isopropyl alcohol, butanol, ethylene glycol, butyl cellosolve, ethyl cellosolve, methyl cellosolve, Lt; RTI ID = 0.0 > of < / RTI > the titania sol.
The cellulose derivative according to claim 1, wherein the cellulose derivative is selected from the group consisting of hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), carboxymethylhydroxyethyl But are not limited to, carboxymethylhydroxyethyl cellulose (CMHEC), hydroxypropylhydroxyethyl cellulose (HPHEC), methyl cellulose (MC), methylhydroxypropyl cellulose (MHPC), methylhydroxy (HMMC), carboxymethylmethyl cellulose (CMMC), hydrophobically modified carboxymethyl cellulose (HMCMC), ethyl cellulose, and mixtures thereof. Lt; RTI ID = 0.0 > of titania < / RTI > Way.
The method according to claim 1,
In the first step, the alcohol is mixed in an amount of 10 to 100 parts by weight based on 1 part by weight of the titanium compound,
Wherein the second step comprises adding 0.01 to 1 part by weight of an acid and water to 1 part by weight of the titanium compound of the first step, the water being 2 to 20% by weight based on the weight of the alcohol,
In the third step, 1 to 30 parts by weight of water and 0.01 to 2 parts by weight of an organic solvent are mixed with 1 part by weight of the titanium compound,
Wherein the fourth step comprises adding 0.01 to 1 part by weight of an acid and 0.01 to 2 parts by weight of a cellulose derivative to 1 part by weight of the titanium compound of the third step.
The method according to claim 1,
The hydrothermal synthesis reaction in the second step is carried out at 150 to 200 ° C and 10 to 20 atm for 2 to 3 hours,
Wherein the fourth step of the aqueous synthetic reaction is carried out at 80 to 100 캜 for 1 to 3 hours.
9. Process according to any one of claims 1 to 8,
Wherein the titania sol contains titanium oxide nanoparticles having an average diameter of 5 nm to 30 nm.
[10] The method of claim 9, wherein the titania sol has a titanium oxide content of 0.5 to 5 wt%
Wherein the content of the cellulose derivative of the titania sol is 0.5 to 2% by weight based on the weight of the titanium oxide.
The titania sol of claim 9, wherein the titania sol has a refractive index of 1.3 or more.
Wherein the optical material is formed or coated with the titania sol of claim 9.

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