KR100947658B1 - Production of metal oxide nano-dispersed transparent solution by semi-batch method - Google Patents

Abstract

The present invention uses a semi-batch method to provide a transparent metal oxide nano dispersion solution that is dispersed without precipitation in solution without the use of a dispersant. Since the metal oxide nano dispersion solution according to the present invention has high refractive characteristics, it is very suitable as an antireflection coating material.

Semi-batch method, metal oxide, high refractive index

Description

Production method of metal oxide nanodispersion transparent solution by semi-batch method {PRODUCTION OF METAL OXIDE NANO-DISPERSED TRANSPARENT SOLUTION BY SEMI-BATCH METHOD}

The present invention relates to a method for producing a metal oxide particle dispersion by a semi-batch method and a metal oxide particle dispersion prepared therefrom. Specifically, metal oxide particles such as titania and zirconia, which have high refractive characteristics and are used in an antireflection coating solution, The present invention relates to a dispersed transparent nano dispersion and a method for preparing the same.

In general, as the use of display devices such as CRTs, LCDs, and PDPs is generalized, not only wear resistance and antifouling properties of the display surface but also external light such as sunlight and fluorescent lights are reflected on the display surface when used under bright lighting. The performance to prevent that is calculated | required. In addition, in addition to such a display, when applied to an external building film or the like, there are many cases in which an antireflection effect is required. In fact, anti-reflective function has been used in our lives even before it is applied to such a display. A representative example is the coating of anti-reflective materials on various lenses such as glasses. In order to impart this anti-reflection function, it is possible to sequentially coat the high refractive coating solution and the low refractive coating solution on the substrate. Generally, a high refractive coating solution is used such as titania or zirconia, and its refractive index is in the range of about 1.8 to 2.2. Is in. As the low refractive coating solution, silica and the like are typically used, and the refractive index is about 1.45. For the anti-reflection effect, the greater the difference in refractive index between the high refractive layer and the low refractive layer, the greater the effect. Thus, until now, research has been conducted in the direction of increasing the refractive index of the high refractive material and in the direction of decreasing the refractive index of the low refractive material.

Recently, attempts have been made to develop inorganic spherical beads in porous or hollow form as high refractive coating materials. Most of them have to undergo a separate process such as dispersing in solution or coating organic materials on the surface to facilitate dispersion. Patent No. 0698935). In most cases, the synthesized high refractive powders have a problem in that a predetermined amount of dispersant and other additives are mixed with a solvent and then subjected to a long dispersion process using a milling equipment.

However, to date, in preparing metal oxide particles such as titania or zirconia, which are highly refractive coating materials, a method of controlling the particle diameter of the metal oxide particles by adding water to a mixture solution of a precursor solution and a hydrolysis catalyst and controlling the injection amount of water Is almost absent.

The technical problem to be achieved by the present invention is to simplify the manufacturing process and mass production by eliminating the process of re-dispersing in the solution after the synthesis of the metal oxide powder to the existing to solve the above problems and to be dispersed in the solution at the same time as the synthesis of the powder It is to provide a method for producing a metal oxide particle dispersion.

In addition, another technical problem to be achieved by the present invention is to use a semi-batch method of injecting water into the mixture solution of the precursor solution and the hydrolysis catalyst and to control the particle size of the metal oxide particles by controlling the content and the injection rate of the injected water It is to provide a manufacturing method for controlling.

In addition, another technical problem to be achieved by the present invention is to provide a metal oxide particle dispersion is prepared by the above manufacturing method is controlled particle diameter and refractive index and excellent dispersibility. More specifically, metal oxide particles having a high refractive index such as titania and zirconia are dispersed to provide a metal oxide particle dispersion suitable for use as a high refractive coating solution for imparting an antireflection function.

In order to achieve the above technical problem, in the present invention, after preparing a mixed solution of a stabilizer, a metal alkoxide and an alcohol solvent, preparing a reaction solution by adding an organic acid to the mixed solution, and adding water to the reaction solution to perform a hydrolysis reaction. It provides a method for producing a metal oxide particle dispersion by a semi-batch method comprising the step of forming a metal oxide particle through and a metal oxide particle dispersion prepared therefrom.

More specifically, it provides a production method that can adjust the particle size of the metal oxide prepared in the range of 2 to 300nm by adjusting the amount of water added to the reaction solution to 5 to 50 molar ratio with respect to the metal alkoxide.

Hereinafter, the present invention will be described in more detail.

At this time, if there is no other definition in the technical terms and scientific terms used, it has a meaning commonly understood by those of ordinary skill in the art. In addition, repeated description of the same technical configuration and operation as in the prior art will be omitted.

The method for preparing a metal oxide particle dispersion according to the present invention includes the following steps.

a) preparing a mixture of a stabilizer, a metal alkoxide and an alcohol solvent;

b) preparing a reaction solution by adding an organic acid to the mixed solution; And

c) injecting water into the reaction solution at a molar ratio of 5 to 50 with respect to the metal alkoxide to form metal oxide particles having a particle size adjusted through a hydrolysis reaction.

In the preparation method according to the present invention, if the injection amount of water is adjusted in the range of 5 to 50 molar ratio with respect to the metal alkoxide, the average particle diameter of the metal oxide particles can be adjusted in the range of 2 to 300 nm according to the molar ratio. When the amount of water to be added is 15 to 40 mole ratio with respect to the metal alkoxide, the average particle diameter of the metal oxide particles can be adjusted to 2 to 200 nm, and when the amount of water to be added is 30 to 40 mole ratio with respect to the metal alkoxide, the metal oxide particles The average particle diameter of can be adjusted to 2 to 60 nm. When the amount of water injected is less than 5 molar ratio with respect to the metal alkoxide, the hydrolysis reaction of the metal alkoxide precursor by water does not occur smoothly, and the unreacted alkoxide material is present. It is not preferable because the decomposition reaction proceeds very fast and aggregation occurs.

In addition, in order to make the particle size distribution of the metal oxide particles produced by inducing a uniform reaction in the reaction solution more uniformly, it is preferable to adjust the addition rate of water in the range of 0.01 to 0.3 mol / min. When the injection rate of the water is less than 0.01 mol / min, the reaction rate is too slow, when it exceeds 0.3 mol / min, it is difficult to produce a metal oxide particles having a uniform size distribution because the particle size distribution of the metal oxide particles is widened . In other words, if less than 0.01 mol / min, the addition rate is slow to become an ideal semi-batch process may be advantageous to the particle size distribution, but adversely in terms of production efficiency. In addition, when the content exceeds 0.3 mol / min, the reaction rate is very fast because it is closer to the batch process rather than the semi-batch, and it is difficult to produce metal oxide particles having a uniform particle size.

The stabilizer serves to increase the stability of the metal oxide particles formed by the hydrolysis reaction may be used a material having a functional group capable of bonding with the metal of the metal alkoxide, β-diketone compound of the formula Is preferably used, and acetylacetone is more preferable in terms of stabilizing effect and compatibility among β-diketone compounds.

[Formula 1]

[In Formula 1, R ¹ and R ² are independently selected from C1 ~ C10 alkyl or C6 ~ C10 aryl group.]

In step b), the concentration of the stabilizer in the reaction solution is preferably 0.5 to 1.5 mol / L (M). When the concentration is less than 0.5M, the reaction solution becomes unstable because it binds only a part of the metal of the metal alkoxide as a precursor. If it exceeds 1.5M, the extra β-diketone compound remains because it acts as an impurity and the transparency is lowered because it may be somewhat disadvantageous as a coating solution.

The metal alkoxide may form metal oxide particles having a high refractive index such as titania or zirconia when using a precursor selected from titanium alkoxide or zirconium alkoxide. Titanium alkoxide may be represented by Ti (OR ³ ) ₄ , zirconium alkoxide may be represented by Zr (OR ⁴ ) ₄ , and R ³ and R ⁴ may be selected from C 1 to C 5 straight or branched alkyl groups.

The concentration of the metal alkoxide is preferably from 0.1 to 1.0 mol / L (M), which produces a metal oxide particle having a small particle diameter when the concentration is less than 0.1M, while very disadvantageous in terms of yield, This is because there are problems that repeated experiments have to be performed several times in order to obtain a positive product, and when it exceeds 1.0 M, metal oxide particles having a very large particle diameter are produced, which may be unsuitable for coating solutions requiring transparency.

The organic acid is used as a catalyst for the hydrolysis reaction, and the kinds thereof include formic acid, propionic acid, acetic acid, n-buturic acid, and n-valeric acid (n -valeric acid), sorbic acid or mixtures thereof, and preferably in the reaction solution has a concentration of 0.05 to 0.5 mol / L (M), more preferably 0.1 to 0.2 mol / L (M). When the concentration of the organic acid is less than 0.05 mol / L, the role of the hydrolysis reaction catalyst is insignificant, and much influence in the direction in which the large particles are produced. When the concentration of the organic acid exceeds 0.5 mol / L, the formation of particles due to the excess organic acid It can lead to substandard results. When using a mineral acid such as hydrochloric acid, nitric acid, sulfuric acid, or _{^{Cl -, NO 3 -, SO}} 4 2- anion may be reduced, such as the mixed or the physical properties of the metal oxide particles and the use of organic acids can be decreased dispersibility It is more preferable to do.

The present invention provides a dispersion of metal oxide particles prepared by the above method, wherein the dispersion is transparent and excellent in dispersion stability. In addition, the metal oxide particles contained in the dispersion have an average particle diameter of 2 to 300 nm, and the smaller the particle diameter, the higher the refractive index. When the metal oxide particles are titania or zirconia particles having a high refractive index, the dispersion is very suitable for use as a high refractive coating solution for imparting antireflection function.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart illustrating a manufacturing process of a transparent nano dispersion in which titania or zirconia is dispersed as an embodiment according to the present invention. Acetyl acetone as a stabilizer, isopropanol as an alcohol solvent, and formic acid as a hydrolysis catalyst are used. As shown in FIG. 1, acetyl acetone and isopropanol are mixed and stirred in one step, followed by mixing and stirring by adding TTIP (titanium tetraisopropoxide) or zirconium tetraisopropoxide (zirconium tetraisopropoxide). Adding formic acid, mixing and stirring, water is added at a constant flow rate in three steps, and the reaction is carried out for about 1 hour and 30 minutes to form a hydrolysis reaction and a polymerization reaction to produce titania or zirconia. In general, the reaction rate of titania and zirconia proceeds rapidly during the hydrolysis and polymerization reaction, which affects the particle size very closely. In the present invention, the amount of water to be added is adjusted in the range of 5 to 50 molar ratio with respect to the TTIP (titanium tetraisopropoxide) or zirconium tetraisopropoxide (zirconium tetraisopropoxide) and the water injection rate is adjusted to 0.01 to 0.3 mol / min The reaction rate was controlled. After the three-step reaction, a nanoparticle dispersion in which titania or zirconia is dispersed having an average particle diameter of 2 to 300 nm and a uniform particle size distribution is obtained.

On the other hand, Figure 2 is a flow chart showing a manufacturing process of the metal oxide nano dispersion solution by a conventional manufacturing method. In the conventional manufacturing method, a dispersant and various additives must be mixed and then milled for a long time in order to wash and dry the synthesized powder and to re-disperse it into a solvent after drying. Therefore, agglomeration of particles occurs in the middle of washing and drying, which is undesirable because it is very difficult to control the size of the particles.

The production method according to the present invention can control the particle diameter of the metal oxide particles formed by adjusting the injection amount and the injection rate of water in the metal precursor reaction solution to which the stabilizer is added, in particular, the transparent dispersion in which titania or zirconia is dispersed is inherently It is very suitable as an anti-reflective coating because it has high refractive characteristics by realizing the refractive index characteristic of. In addition, as described above, when the transparent titania or zirconia nano dispersion is directly used as a high refractive coating agent, the washing process, drying process, and dispersion process, which must be performed in the process of redispersing the conventional synthesized powder, can be omitted. It has the advantage of lowering the cost of the product and mass production.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

<Example 1>

1 mol of acetylacetone is mixed with isopropanol and stirred for 10 minutes. Then, the molar ratio of water to TTIP (titanium tetraisopropoxide, reagent grade) was changed from 5 to 50, and then weighed. First, 1 mol of TTIP was added to the mixed solution of acetylacetone and isopropanol, and stirred for 10 minutes to increase the acetylacetone concentration. 1 M (mol / L), 1 L of a mixed solution having a TTIP concentration of 1 M was prepared. Subsequently, 0.15 mol of formic acid was added to the mixed solution, followed by stirring for 3 minutes to prepare a reaction solution. Water was added to the reaction solution at room temperature, but water was added at the injection rate shown in Table 1 below, followed by stirring for 1 hour and 30 minutes after completion of addition to obtain a transparent titania nano dispersion. The titania particle size decreased proportionally up to 40 as the molar ratio of water to TTIP increased, and then increased again. The value of the refractive index decreased proportionally as the average particle size increased. The refractive index was highest when the molar ratio of water to TTIP was 30-40 and very low above 50. The refractive index of the titania dispersion prepared according to the present example and the titania particle diameter in the dispersion were shown in Table 1 below. The Titania particle diameter in the dispersion was measured using a DLS (Dynamic Light Scattering) measuring instrument (Model: LPA-3000, 3100) manufactured by Otsuka.

TABLE 1

<Example 2>

Zirconia particles were prepared in the same manner as in Example 1, except that 1 mole of zirconium tetraisopropoxide (zirconium tetraisopropoxide, reagent grade) was used. The size of zirconia particles decreased proportionally up to 40 as the molar ratio of water to zirconium tetraisopropoxide increased and then increased again, and the refractive index decreased with increasing average particle size. The refractive index was highest when the molar ratio of water to zirconium tetraisopropoxide was 30 to 40 and was very low above 50. On the other hand, when comparing titania and zirconia under the same conditions, it was found that the average particle diameter of titania is smaller and the refractive index is higher than that of zirconia. The properties of the zirconia particles obtained according to this example are shown in Table 2 below.

TABLE 2

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a flow chart showing a manufacturing process of a transparent metal oxide nano dispersion solution according to an embodiment of the present invention.

Figure 2 is a flow chart showing a manufacturing process of the metal oxide nano dispersion solution by a conventional manufacturing method.

Claims (10)

a) stabilizer at a concentration of 0.5 to 1.5 mol / L (M), at a concentration of 0.1 to 1.0 mol / L (M)  Preparing a mixture of a metal alkoxide and an alcohol solvent b) adding the organic acid at a concentration of 0.05 to 0.5 mol / L to the mixed solution to   Manufacturing step and c) injecting water into the reaction solution at a rate of 5 to 50 molar ratio and 0.01 to 0.3 mol / min with respect to the metal alkoxide to form metal oxide particles for adjusting the average particle diameter of the particles to 2 to 300 nm. Method for producing a metal oxide particle dispersion by a semi-batch method comprising a. delete delete delete The method of claim 1, and c) adding water at a molar ratio of 15 to 40 to the metal alkoxide in step c) to adjust the average particle diameter of the metal oxide particles to 2 to 200 nm. The method of claim 1, and c) adding water at a molar ratio of 30 to 40 to the metal alkoxide in step c) to adjust the average particle diameter of the metal oxide particles to 2 to 60 nm. The method of claim 1, The metal alkoxide is a method for producing a metal oxide particle dispersion by a semi-batch method, characterized in that selected from titanium alkoxide or zirconium alkoxide. The method of claim 1, The stabilizer is a method for producing a metal oxide particle dispersion by a semi-batch method, characterized in that the β-diketone compound of the formula (1). [Formula 1]

[In Formula 1, R ¹ and R ² are independently selected from C1 ~ C10 alkyl or C6 ~ C10 aryl group.] The method of claim 1, The organic acid is formic acid, propionic acid, acetic acid, n-buturic acid, n-valeric acid, sorbic acid or a mixture thereof. Method for producing a metal oxide particle dispersion by a semi-batch method, characterized in that selected from. delete

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