KR20150108462A - Preparation of size-controlled silica-zirconia composite sol by sol-gel - Google Patents

Abstract

The present invention provides a particle size-controlled silica-zirconia composite sol, and a method for preparing the same. The method of the present invention comprises the following steps (1)-(3): (1) adding a first hydrolysis solution to a silica precursor solution, and primarily hydrolyzing the mixture at 50 to 90°C for 30 minutes to 2 hours; (2) adding a zirconia precursor solution and a second hydrolysis solution to the mixture obtained in the step (1), and secondarily hydrolyzing and condensing the resultant mixture at 50 to 90°C for 1 to 24 hours; and (3) adding a third hydrolysis solution to the resultant mixture obtained in the step (2), and condensing the resultant mixture at 100 to 140°C for 4 to 24 hours while removing water. The silica-zirconia composite sol of the present invention: has uniform particle size distribution and a low aggregation value; and can be maintained stable without precipitation for a long period of time.

Description

Preparation of Size-Controlled Silica-Zirconia Composite Sol by Sol-Gel Method Preparation of size-controlled silica-zirconia composite sol by sol-

The present invention relates to a method for preparing a size-controlled silica-zirconia composite sol by a sol-gel method, and more particularly, to a method for controlling the particle size of a silica-zirconia complex sol by controlling the rate of hydrolysis reaction and the concentration of a silica precursor To a process for producing size-controlled silica-zirconia complex sols.

The silica-zirconia complex sol is widely synthesized by chemical / physical properties such as high thermal / chemical stability, mechanical strength, high specific surface area and the like, like general inorganic sol. Silica-zirconia composite particles have been applied to ceramic toughning, alkali-resistant glass, solid super acid, heterogeneous catalysis, and the like. The physical properties and properties differ depending on the degree of mixing.

Examples of the preparation method of the silica-zirconia complex sol include mechanical preparation, rearrangement of zirconia with silicate, impregnation, coprecipitation and sol-gel method. Among them, the sol-gel process can be used for physical / It is one of the most effective recipe [S. Kang, K.-S. Park, D.-S. Bae, Synthesis and microstructure of silica-zirconia composite nanoparticles by a sol-gel processing, Eng. Res. Tech. , 5 (2005), p.367-371).

The sol-gel process is performed by the hydrolysis and condensation of metal alkoxide. It can produce various kinds of materials and has the advantage of obtaining desired physical properties at a relatively low temperature. The molecular structure, high specific surface area, The pore control is characterized by a uniform distribution in all the composites. Also, applications of the sol-gel process for the production of materials in which two or more materials are mixed are widely known. For example, in the Stober method, ammonia catalysts are used in this way to convert 150 to 500 nm sized monodisperse silica (SiO 2, SiO 2) from various silicon alkoxides to tetraethylorthosilicate (TEOS) ₂ ) particles [W. St ㆆ ber, A. Fing, E. Bohn, Controlled growth of monodispersed silica spheres in the micro size range, J. Colloid Interface. Sci. , 26 (1968), p.

On the other hand, silica particles generally undergo hydrolysis-condensation reaction at room temperature by sol-gel method under TEOS and water, acid or base environment. The results obtained have the same structure as silica but grow as spherical particles and glassy growth due to the formation of three dimensional network structure by the effect of catalyst. The reaction mechanism at this time is represented by the formula Si (OC ₂ H ₅ ) ₄ + 2H ₂ O → SiO ₂ + 4C ₂ H ₅ OH. Generally, under acid catalysis, the hydrolysis rate is relatively faster than the condensation reaction rate. The alkoxide has a polymeric sol form that forms a three-dimensional network structure. It has been reported that the time taken for gelation in the order of HF, acetic acid, hydrochloric acid, nitric acid, and sulfuric acid increases at the same concentration, depending on the type of catalyst. On the other hand, in the case of the base catalyst, the condensation reaction rate is faster than the hydrolysis reaction rate and the spherical colloidal particles can be obtained, which is greatly influenced by the type of alcohol used, the concentration of the catalyst used in the reaction, and the amount of water added. Therefore, it is possible to form particles having various structures or sizes according to the synthesis conditions. (CJ Brinker and GW Schere, Sol-Gel Science: The Physics and Chemistry of Sol-Gel Processing, ACADEMIC PRESS, INC., 1990; J. Mater. Process. Technol., 199 (2008), p. )

Coatings, etc., it is important to ensure dispersion stability in a nanoparticle suspension in which nano-sized silica particles and a continuous phase solvent are dispersed. Variables affecting dispersion stability include pH, salt dissolved in solvent, particle size, and solvent polarity. When the dispersibility of the silica sol varies depending on the surface functional groups and the dispersing solvent, for example, when polarity silica of hydrophilic nature is dispersed in a non-polar solvent such as toluene, aggregation and crease It has been reported that hydrophobic silica particles are more agglomerated and creaming phenomenon when the hydrophilic silica particles are dispersed in ethanol which is a polar solvent. Therefore, when the polarity of the particle surface and the polarity of the solvent coincide, better dispersion stability can be secured. J. Am. Ceram. Soc., 84 (2001), p. 713-718). ≪ / RTI >

The precursor for the synthesis of zirconia sol is zirconium acetate (Zr ^{x +} .x CH ₃ COOH), zirconyl chloride octahydrate (ZrOCl ₂ .8H ₂ O), zirconium acetate It can be exemplified butoxide _{(Zr (OC 4 H 9)} 4, ZrTB) , etc. - zirconyl nitrate hydrate _{(ZrO (NO 3) 2 ·} x H 2 O), zirconium (IV) tert.

Under these circumstances, studies have been carried out to synthesize stable silica-zirconia complex sols with various size distributions by sol-gel method using silica precursor (eg, TEOS) and zirconia precursor (eg, ZrTB) There has been a need for invention.

The present inventors have found that by first hydrolyzing a silica precursor to prepare a silica sol, adding a zirconia precursor thereto, secondly hydrolyzing the resulting mixture, and then hydrolyzing and condensing the additional hydrolysis solution , A silica-zirconia composite sol can be produced which is uniform in particle size distribution, less aggregated, and can be maintained in a stable state without formation of a long-term precipitation, thereby completing the present invention.

The silica-zirconia composite sol prepared according to the production method of the present invention can be maintained in a stable state without uniformity of particle size distribution, less aggregation, and long-term precipitation formation.

Fig. 1 is a diagram illustrating a manufacturing method of the present invention,
Fig. 2 is an initial particle size distribution diagram (Fig. 2a) of the composite sol prepared in Example 1 and a particle size distribution diagram (Fig. 2b) of supernatant after 6 months.
Fig. 3 is a schematic diagram of the manufacturing method of Comparative Example 1. Fig.
FIG. 4 is a graph showing an initial particle size distribution diagram (FIG. 4A) of the composite sol prepared in Comparative Example 1 and a particle size distribution diagram (FIG. 4B) of the supernatant after 6 months.
FIG. 5 is a graph showing the distribution of particle size measurement values of the composite sol prepared in Comparative Example 1. FIG.
6A to 6D are SEM photographs of a sol, showing the silica-zirconia composite sol (FIG. 6A) and its precipitate (FIG. 6B) prepared in Example 1 and silica sol (FIG. 6C) and zirconia sol .
FIG. 7A is a particle size distribution chart of a composite sol having an average particle size of 100 nm prepared in Example 1 and Comparative Example 1, and FIG. 7B is an SEM photograph of a composite sol having an average particle size of 100 nm prepared in Example 1.
8 is a graph showing the distribution of zeta potential measurements according to TEOS concentration in Example 1 ()) and Comparative Example 1 (占).

A first object of the present invention is to provide a process for preparing a particle size-controlled silica-zirconia complex sol comprising the steps of:

(1) A silica precursor solution is added to a primary hydrolysis solution, and the resulting reaction mixture is heated at a temperature of 50 to 90 DEG C, specifically 60 to 80 DEG C, for 30 minutes to 2 hours, The mixture was subjected to a primary hydrolysis reaction for 30 minutes,

(2) adding a zirconia precursor solution and a second hydrolyzed solution to the reaction mixture obtained in the step (1), and heating the resultant reaction mixture at a temperature of from 50 to 90 ° C, Followed by a secondary hydrolysis reaction and a condensation reaction for 24 hours,

(3) adding a tertiary hydrolysis solution to the reaction mixture obtained in the step (2), and heating the resultant reaction mixture at a temperature of 100 to 140 ° C, specifically 110 to 130 ° C for 4 to 24 hours, Condensate by removing water for 2 to 12 hours.

A second object of the present invention is to provide a particle size-controlled silica-zirconia composite sol prepared according to the above process and having an average particle size of 500 nm or less, specifically 400 nm or less, preferably 300 nm or less .

According to one embodiment of the present invention, the above primary hydrolysis solution may be a mixed solution of EtOH, water and hydrochloric acid.

According to a preferred embodiment of the present invention, said silica precursor may be selected from tetraalkylorthosilicates, specifically tetraethylorthosilicate (TEOS) or tetrabutylorthosilicate (TBOS); The above-described zirconia precursors include zirconium acetate (Zr ^{x +} x CH ₃ COOH), zirconyl chloride octahydrate (ZrOCl ₂ .8H ₂ O), zirconyl nitrate hydrate (ZrO (NO ₃ ) ₂ x H ₂ O), zirconium (IV) tert -butoxide (Zr (OC ₄ H ₉ ) ₄ , ZrTB).

According to one embodiment of the present invention, the silica precursor, zirconia precursor and water may be used in a molar ratio of Si: Zr: H ₂ O = 0.1-5: 0.1-5: 1 to 40, The precursor is preferably used in step (1) at an initial concentration of 0.1 to 0.5 wt%.

According to one preferred embodiment of the present invention, the process for preparing a particle size-controlled silica-zirconia complex sol may comprise the following steps:

(1) gelation and / or hydrolysis (primary hydrolysis) of a solution containing a silica precursor, ethanol, water and hydrochloric acid at a temperature of 50 to 80 캜 for 30 minutes to 2 hours,

(2) adding ethanol, water and hydrochloric acid, if appropriate, to the reaction mixture obtained in step (1) above, followed by addition of a zirconia precursor, and then heating at a temperature of 50 to 80 DEG C for 1 to 24 hours Hydrolysis (secondary hydrolysis)

(3) Ethanol, water and hydrochloric acid are further added to the reaction mixture obtained in the step (2), and the condensation reaction is carried out at a temperature of 100 to 140 ° C for 4 to 24 hours while removing water.

According to one embodiment of the present invention, water can be used in an amount of less than 1/4 of the entire process input.

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

In the present invention, the silica-zirconia (SiO ₂ -ZrO ₂ ) composite sol is a composite oxide in which a silica (SiO ₂ ) portion and a zirconia (ZrO ₂ ) portion are chemically bonded to each other in the form of a composite oxide (SiZrO ₄ ) Refers to a sol containing SiO ₂ -ZrO ₂ composite particles, for example, a composite particle in which silica particles and zirconia particles are connected by a chemical bond in the form of a composite oxide. Unlike the composite particles of the composite oxide (SiZrO ₄ ), the composite particles of this type are complicated to manufacture and difficult to control the particle size.

In the present invention, the hydrolysis reaction and the condensation reaction can be carried out according to the raw materials and conditions used in conventional silica or zirconia sol-gel synthesis methods. The hydrolysis solution may be a solution used to hydrolyze the silica precursor and the zirconia precursor, and may include a solvent, water, and a catalyst. As the solvent, a water-soluble organic solvent such as ethanol may be mentioned. As the catalyst, Alkaline catalysts such as an acid catalyst, sodium hydroxide and ammonium chloride can be mentioned. Preferably, the hydrolysis solution comprises ethanol, water and hydrochloric acid. The primary, secondary and tertiary hydrolysis solutions may be the same or different.

According to one preferred embodiment of the present invention, the silica-zirconia complex sol can be prepared by a process comprising the steps of:

Step 1: [Introduction of silica precursor solution]

A silica precursor such as TEOS and a solvent such as EtOH are introduced into the reactor, and then the temperature is adjusted to 50 to 90 占 폚.

- Step 2: [Primary hydrolysis step]

A primary hydrolysis solution (for example, a solvent such as ethanol, water and HCl) was slowly added dropwise to the silica precursor solution of the step 1 with stirring and then stirred for 30 minutes to 2 hours to obtain A-1 for the primary hydrolysis reaction (Hydrolysis reaction of the silica precursor) is carried out by injecting a solution, and at this time, it is preferable to use only 1/4 to 1/2 of the total amount of water.

Step 3: [Introduction of zirconia precursor solution and secondary hydrolysis step]

To the reaction mixture obtained in the step 2), a solution B (zirconia precursor solution) containing a high purity ethanol, preferably high purity ethanol containing little water, and a zirconia precursor such as ZrTB was slowly added dropwise with stirring, Deg.] C for 1 to 2 hours, and the secondary hydrolysis reaction (primary hydrolysis reaction of the zirconia precursor) proceeds while slowly injecting A-2.

Step 4: [tertiary hydrolysis step]

The tertiary hydrolysis solution A-3 is added to the reaction mixture obtained in the step 3), and then the tertiary hydrolysis reaction is carried out for 2 hours, and then the pH of the solution can be adjusted by using HCl.

- Step 5: [condensation phase]

The reaction mixture obtained in the step 4) was heated to 100 DEG C and stabilized for about 30 minutes, then heated to 120 to 125 DEG C at a heating rate of 5 DEG C / 1 to 10 minutes, and water was distilled off for about 8 hours Condensation reaction is carried out while removing. At this time, the distilled water is adjusted by using a dropping funnel provided at the lower part of the condenser so that a certain amount of water can be present in the reaction system.

The reactions of the above steps 1 to 5 may be modified as necessary.

When the silica precursor (eg, TEOS) and the zirconia precursor (eg, ZrTB) polymerize at a 1: 1 ratio, the complex oxide-like linkage structure may have a linear or cross-linking structure (see FIG. In the case of hydrolysis and polymerization, the precursor is hydrolyzed and then macromolecules are formed by the polymerization reaction, which is an inert material. Thus, the nonvolatile residual coefficient can be seen as the residual ratio of the polymeric material, which can be used to evaluate the reaction rate. Since the theoretical residual amount is 0.7937 at full cross-linking and 0.9536 at complete linear linkage, the residual amount in the preparation of silica-zirconia composite sol generally exists between these values (J. Sol-Gel Sci. Technol. 53 (2010), p. 93-99).

When the ratio of Si: Zr: H ₂ O is varied, the theoretical residual amount is 0.7937 to 0.9536, but the higher the value is, State, and a low value exists as a single molecule, indicating a hydrolyzed state. In general, when the reaction was carried out according to the catalyst concentration, the reaction rate was the fastest when the molar ratio of Si: Zr: H ₂ O was 1: 1: 80 and HCl 1.0wt%, the molar ratio was 1: 1: 80, wt%, 24 hours reaction. The lower the water ratio, the lower the reaction rate.

In the present invention, when Si: Zr = 1: 1, the molar ratio of (Si + Zr): H ₂ O is 1:10 to 80, specifically 1:20 to 60, Lt; / RTI > If the ratio of water is too low, the reaction rate becomes slow. If the water ratio is too high, the hydrolysis reaction proceeds rapidly, which makes it difficult to control the reaction.

Comparing electron micrographs, silica has spherical particle shapes of uniform size, while zirconia has a cluster of fine particles and a cohesive size distribution (see FIG. 6). Generally, as the concentration of water in zirconia production increases, the particle size becomes finer and the cohesion of fine particles becomes stronger. Therefore, the error of the particle size analysis becomes severe according to the degree of coagulation. Therefore, It is necessary to control the size of the pores for the synthesis of silica-zirconia having a uniform distribution and stable morphology below.

Therefore, in the present invention, by reducing the concentration of the silica precursor, for example, by reducing the concentration of the silica precursor to 1.0 wt% in the present invention to 0.2 wt% in the present invention, the molar ratio of water is adjusted to control the particle size, . In addition, the hydrolysis can be controlled in three steps to adjust the reaction rate and thereby control the particle size.

In general, in the sol-gel reaction using an acid catalyst, the rate of hydrolysis proceeds very rapidly and thus affects the morphology of the sol. The conventional method has a one-step hydrolysis process of injecting zirconia after the hydrolysis of silica. In the present invention, the rate of hydrolysis is controlled by dividing the hydrolysis step by three steps, thereby reducing the formation of large particles, thereby forming a stable silica-zirconia complex sol.

The silica-zirconia composite sol prepared as described above has a uniform particle size distribution, less aggregation, and can be maintained in a stable state without forming a long-term precipitation.

On the other hand, a zeta potential, which means a potential difference between a shear boundary and a bulk solution, is often used as an index indicating the degree of surface charge of colloidal particles suspended in a liquid. The zeta potential is directly related to the stability of the colloid. An increase in the zeta potential means that the colloid is stable, and a decrease in the zeta potential means that the colloid is unstable. The stability of the silica-zirconia complex sol according to the present invention can be confirmed by this zeta potential.

The present invention can be further illustrated by the following examples.

[Example]

Abbreviations used in the examples are as follows:

TEOS: tetraethoxyorthosilane,

ZrTB: Zirconium (IV) tert -butoxide

EtOH: ethanol,

HCl: hydrochloric acid.

Example 1:

To prepare a zirconia complex sol (SiO ₂ -ZrO ₂₎ - carrying out a car according to the procedure. The names and types of materials used are listed in Table 1 below:

Step 1: [Introduction of silica precursor solution] TEOS and EtOH were introduced into a 3-necked round bottom flask (500 mL) equipped with a magnetic stirrer, an oil bath, a dropping funnel (dropping funnel) and a cooling condenser, The temperature was adjusted to 70 캜;

Step 2: [Primary hydrolysis step] To the silica precursor solution obtained in the above step 1), a solution A-1 (silica hydrolysis solution) containing ethanol, water and HCl was slowly added dropwise with stirring, For a period of time to proceed the primary hydrolysis reaction (hydrolysis reaction of the silica precursor), wherein water is used in an amount of only 1/4 to 1/2 of the total charge;

Step 3: [Introduction of zirconia precursor solution and secondary hydrolysis step] To the reaction mixture obtained in the step 2), a solution B (zirconia precursor solution) containing high purity ethanol and ZrTB was slowly added dropwise with stirring, and 70 (1/4 to 1/2 of the total amount of water was added) to proceed the secondary hydrolysis reaction for 1 to 12 hours,

- Step 4: [Tertiary hydrolysis step] To the reaction mixture obtained in the step 3), a solution A-3 for tertiary hydrolysis (water is used in an amount of 1/4 to 1/2 of the total amount) is added After 3 hours of hydrolysis for 2 hours, the pH of the solution was adjusted using HCl,

Step 5: [Condensation step] The reaction mixture obtained in step 4) is heated to 100 DEG C, stabilized for about 30 minutes, heated to 120 to 125 DEG C at a heating rate of 5 DEG C / Condensation reaction is carried out with removal of water by distillation for about 8 hours. At this time, the distilled water is adjusted by using a dropping funnel provided at the lower part of the condenser so that a certain amount of water can be present in the reaction system.

Table 1 below shows the average particle size and zeta potential of silica-zirconia composite sol prepared at various molar ratios of Si: Zr: H2O in Example 1.

Sol name Si: Zr: H ₂ O TEOS concentration [wt%] Average particle size [nm] Zeta potential
[mV] Early Three months later SZ-18 1: 1: 4 1.0 198 188 20.7 SZ-19 1: 1: 4 1.0 521.9 680 10.6 SZ-20 1: 1: 4 0.5 162.2 188 32.4 SZ-21 1: 1: 4 0.5 77.38 62.5 27.5 SZ-22 1: 1: 4 0.2 232 293 24.3 SZ-23 1: 1: 4 0.2 189 252 26.9 SZ-30 1: 1: 4 0.2 95.3 43.0

The composite sol prepared according to the present invention had an average particle size of 300 nm or less and no layer separation due to precipitation was observed even after 6 months. In addition, Table 1 shows that the average particle size of the composite sol produced in the present invention does not significantly differ from the initial value even after 3 months have elapsed. Therefore, it can be seen that the stability of the silica-zirconia composite sol according to the present invention is remarkably high in a solution state.

Comparative Example 1A (comparative):

A comparative silica-zirconia composite sol (SiO ₂ -ZrO ₂ ) was prepared according to the conventional production method.

To prepare a zirconia complex sol (SiO ₂ -ZrO ₂₎ - carrying out a car according to the procedure. The names and types of materials used are listed in Table 2 below:

Step 1) TEOS and EtOH were introduced into a 2-necked round bottom flask (500 mL) equipped with a magnetic stirrer, an oil bath and a cooling condenser at an initial concentration, then the temperature was adjusted to 70 DEG C,

Step 2) To the TEOS solution obtained in the step 1), a solution containing ethanol, water and HCl as the hydrolysis solution A was slowly added dropwise with stirring, and the mixture was stirred for 1 hour to proceed the hydrolysis reaction,

Step 3) To the reaction mixture obtained in the step 2), a solution B containing ethanol and ZrTB as the hydrolysis solution B was slowly added dropwise with stirring, and the mixture was stirred for 1 to 24 hours to progress hydrolysis and condensation ,

Step 4) Purification and / or separation of the prepared silica-zirconia sol.

(Comparative Example 1A) Synthesis of silica-zirconia sol (Si: Zr: H ₂ 0 = 1: 1: 8, HCl = 0.2 wt% step Early A B Name of sample TEOS EtOH H ₂ O HCl EtOH ZrTB EtOH Usage (g) 3.00 270.09 2.08 0.11 10.00 4.72 10.00 mol ratio 1.00 93.62 8.02 0.21 3.47 1.00 3.47

Comparative Examples 1B to F (Comparative):

And were prepared zirconia complex sol (SiO ₂ -ZrO _2), the proportion of the material used in each step are described below in Table 3 by repeating the method described in Comparative Example 1A embodiment Car:

Manufacturing example TEOS
(g) H ₂ O
(g) HCl
(g) ZrTB
(g) Si: Zr: H ₂ O (molar ratio) HCl (content) 1B 3.0 5.2 0.11 4.72 1: 1: 20 0.2 wt% 1C 3.0 10.4 0.11 4.72 1: 1: 40 0.2 wt% 1D 3.0 20.8 0.11 4.72 1: 1: 80 0.2 wt% 1E 3.0 2.08 0.59 4.72 1: 1: 8 1wt% 1F 3.0 20.8 0.59 4.72 1: 1: 80 1wt%

Table 4 below shows the average particle size and zeta potential of the silica-zirconia composite sol prepared at a molar ratio of various Si: Zr: H ₂ O in Comparative Example 1.

Particle size analysis and zeta potential of the composite sol of Comparative Example 1
Sol name Si: Zr: H ₂ O TEOS concentration
[wt%] HCl concentration
[wt%] Average particle size [nm] Zeta potential
[mV] Early 6 months later SZ-1 1: 1: 8 1.0 0.2 1383 164 8.8 SZ-2 1: 1: 8 1.0 0.2 34.3 28.6 SZ-3 1: 1: 80 1.0 0.2 652 22.7 SZ-4 1: 1: 8 1.0 1.0 20.6 4.0 SZ-5 1: 1: 40 1.0 0.2 616 274 25.5 SZ-6 1: 1: 80 1.0 1.0 2225 587 SZ-7 1: 1: 80 1.0 0.2 166 SZ-8 1: 1: 80 1.0 1.0 364 463 SZ-9 1: 1: 80 1.0 0.2 1071 218 SZ-10 1: 1: 80 1.0 0.2 (NH ₄ OH) 730 229 SZ-11 1: 1: 8 1.0 0.2 18.2 SZ-12 1: 1: 40 1.0 0.2 186 SZ-13 1: 1: 80 1.0 0.2 170 SZ-14 1: 1: 20 1.0 0.2 135 SZ-15 1: 1: 20 1.0 0.2 109

FIG. 3 shows a schematic diagram of a conventional general manufacturing method and a manufacturing method of Comparative Example 1.

FIG. 4 shows the particle size of the composite sol prepared in Comparative Example 1, which shows a small particle size when the molar ratio of water is small and a tendency that the particle size increases as the molar ratio of water increases. However, The larger the error value is, the larger the error value is.

Fig. 5 shows the initial particle size distribution (Fig. 5a) of the composite sol prepared in Example 1 and the particle size distribution diagram of the supernatant after 6 months (Fig. 5b). It is shown that when the molar ratio of water is large, This is because the particle size distributions tend to be excessively large because the particles are in a state of agglomeration as the mole ratio is larger rather than being uniformly distributed in the solution. After 6 months of storage of the stock solution, re - measurement of the particle size showed that most of the solution retained as the undiluted solution showed sedimentation and the average particle size tended to decrease as a result of re - measurement with the supernatant. From this, it is judged that the conventional preparation method, that is, the composite sol prepared by the method of Example 1 forms an unstable solution.

Test Example 1: Comparison of particle size analysis of colloidal particles

Particle size analysis was compared for the composite sol (SZ-15) of Comparative Example 1 and the composite sol (SZ-30) of Example 1, both of which had different average particle sizes of 100 nm.

As shown in FIG. 7A, the composite sol (SZ-30) of Example 1 has a narrower particle size distribution than that of the composite sol (SZ-15) of Comparative Example 1, showing uniform particle size distribution. 7B is an SEM photograph of the composite sol (SZ-30) of Example 1, showing a very uniform particle size distribution.

Test Example 2: Comparison of colloid particle stability

The particle stability of the practical ka-zirconia composite sol prepared in Examples and Comparative Examples can be confirmed by the zeta potential (see Table 1 and Table 4).

As can be seen from FIG. 8, when the TEOS concentration is low, the zeta potential increases and the dispersion stability tends to be exhibited. The tendency of ionization is less than that at a high concentration, Dispersion is expected to be uniform. When the concentration is high, the possibility of cross-linking in the solution increases, and the zeta potential decreases due to the decrease in dispersion stability and relative stability. When the concentration is increased, the ion force becomes larger and a zeta potential value . That is, aggregation of ions is expected.

The zeta potential was measured in EtOH solvent in Comparative Example 1 (Table 4), and the zeta potential was measured in Example 1 (Table 1) using water as a dispersion medium. Generally, an increase in the zeta potential value affects the dispersion stability improvement of the dispersed sol in the solution. As shown in FIG. 8, the zeta potential of Example 1 is higher than that of Comparative Example 1. The reason is that the use of EtOH is less polar than water and therefore less ionization is expected to result in more cross-linked particles than linearly distributed particles. As a result, (Chih Hoon Kang, Sung Wook Hong, Yong Tae Kang, Junemo Koo., The Effects of the Surfactant Type on the Nanofluids Stability. Proceedings, p. 275-280).

INDUSTRIAL APPLICABILITY The present invention can be industrially used in industrial fields in which silica-zirconia composite sol or composite particles are used as a catalyst, a catalyst carrier, a filler, a filler and the like.

Claims (11)

A process for preparing a particle size-controlled silica-zirconia complex sol comprising the steps of:
(1) adding a primary hydrolysis solution of a silica precursor solution, subjecting the resulting reaction mixture to primary hydrolysis at a temperature of 50 to 90 ° C for 30 minutes to 2 hours,
(2) adding a zirconia precursor solution and a secondary hydrolysis solution to the reaction mixture obtained in the step (1), and subjecting the resulting reaction mixture to a secondary hydrolysis reaction at a temperature of 50 to 90 ° C for 1 to 24 hours And condensation reaction,
(3) adding a tertiary hydrolysis solution to the reaction mixture obtained in the above step (2), and causing the resulting reaction mixture to undergo condensation reaction at a temperature of 100 to 140 ° C for 4 to 24 hours while removing water. The process for producing a size-controlled silica-zirconia composite sol according to claim 1, wherein the hydrolysis solution is a mixed solution of EtOH, water and hydrochloric acid. The method of claim 1, wherein the aforementioned silica precursors may be selected from a tetraalkyl orthosilicate, the above-described zirconia precursor, zirconium acetate _{^{(Zr x + · x CH 3}} COOH), zirconyl chloride octa hydrate (ZrOCl ₂ · 8H ₂ O), zirconyl nitrate hydrate (ZrO (NO ₃ ) ₂ x H ₂ O), zirconium (IV) tert -butoxide (Zr (OC ₄ H ₉ ) ₄ , ZrTB) Zirconia < / RTI > complex sol, characterized in that the size- The method of claim 1, wherein the silica precursor, zirconia precursor and water are used in a molar ratio of Si: Zr: H ₂ O = 0.1 to 5: 0.1 to 5: 1 to 40, A process for producing a silica-zirconia complex sol. A process for producing a size-controlled silica-zirconia composite sol according to claim 4, characterized in that the above-described silica precursor is used in an initial concentration of 0.1 to 0.5 wt% in step (1) The method of claim 1, wherein the particle size-controlled silica-zirconia composite sol comprises the steps of:
(1) A solution containing a silica precursor, ethanol, water and hydrochloric acid is subjected to a primary hydrolysis reaction at a temperature of 50 to 80 캜 for 30 minutes to 2 hours,
(2) adding a zirconia precursor to the reaction mixture obtained in the step (1), then performing secondary hydrolysis at a temperature of 50 to 80 ° C for 1 to 24 hours,
(3) Ethanol, water and hydrochloric acid are further added to the reaction mixture obtained in the step (2), and the condensation reaction is carried out at a temperature of 100 to 140 ° C for 4 to 24 hours while removing water. A process for producing a particle size-controlled silica-zirconia composite sol according to claim 1 or 6, wherein in step (1) described above, water is used in an amount of 1/4 or less of the total amount of the process . The method according to any one of claims 1 to 6, wherein in step (3) described above, the reaction mixture obtained in step (2) is further added with ethanol, water and hydrochloric acid and further reacted for 2 to 3 hours, Is subjected to a condensation reaction at a temperature of 100 to 1400 占 폚 for 4 to 24 hours while removing water, thereby producing a controlled particle size-controlled silica-zirconia composite sol. 9. The process according to claim 8, wherein in step (3) described above, the reaction mixture obtained in step (2) is further reacted with ethanol, water and hydrochloric acid for a further 2 to 3 hours, The pH of the reaction mixture is adjusted and allowed to stand for 10 minutes to 1 hour to stabilize, and the temperature is slowly raised at a temperature rising rate of 2 to 5 DEG C / 10 minutes. Size-controlled silica-zirconia composite sol. 2. The process of claim 1, wherein water is removed in an azeotropic manner during the reaction in step (3). A particle size-controlled silica-zirconia complex sol prepared according to the method of claim 1 and having an average particle size of 300 nm or less.

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