KR20200102737A - Method for manufacturing aluminosilicate nanoparticles with developed mesopore - Google Patents

Abstract

The present invention relates to a method for manufacturing aluminosilicate nanoparticles with developed mesopores. According to the manufacturing method, aluminosilicate nanoparticles having excellent specific surface area properties and developed mesopores are provided. The properties of the aluminosilicate nanoparticles allow the aluminosilicate nanoparticles to exhibit excellent dispersibility in a rubber composition, as well as improved workability and productivity in a rubber molding process.

Description

Manufacturing method of aluminosilicate nanoparticles with developed mesopores {METHOD FOR MANUFACTURING ALUMINOSILICATE NANOPARTICLES WITH DEVELOPED MESOPORE}

The present invention relates to a method for preparing aluminosilicate nanoparticles having developed mesopores.

As concerns over global warming and environmental issues spread, the concept of eco-friendly energy to reduce carbon emissions by increasing energy efficiency is being emphasized in many ways. This eco-friendly concept is being visualized in the tire industry as a result of the development of highly efficient eco-friendly tires and the search for a method of recycling waste tires.

Eco-friendly tires (or green tires) refer to tires that lower the rolling resistance of rubber to give high efficiency and high fuel efficiency characteristics, and consequently reduce carbon emissions. In order to manufacture such eco-friendly tires, modified rubber materials and white additives for rubber reinforcement (eg, precipitated silica) are mainly used.

In general, silica materials have problems such as low dispersibility in the rubber composition and loss of wear resistance. In order to compensate for this, it is known that an eco-friendly tire material having good wear resistance can be made by using a highly dispersible precipitated silica under a specific condition together with a silane coupling agent.

On the other hand, there is also a high interest in additives that can favorably have opposite properties (mechanical strength such as rolling resistance and abrasion resistance) like highly dispersible precipitated silica. It is known that even when alumina, clay, kaolin, etc. are applied as a white additive for rubber reinforcement, it can be used as an eco-friendly tire material by lowering rolling resistance. However, the white additive for rubber reinforcement decreases dispersibility due to the formation of strong aggregates, and thus, problems such as a decrease in mechanical strength may appear.

Kay Saalwachter, Microstructure and molecular dynamics of elastomers as studied by advanced low-resolution nuclear magnetic resonance methods, Rubber Chemistry and Technology, Vol. 85, No. 3, pp. 350-386 (2012).

The present invention is to provide a method for producing aluminosilicate nanoparticles having developed mesopores and capable of exhibiting excellent dispersibility in a rubber composition for a tire.

According to the present invention,

Injecting an alkaline silicon source into the reactor,

Injecting an acidic aluminum source including aluminum potassium sulfate and isopropyl alcohol into the reactor and stirring,

Forming an aluminum silicate salt by neutralizing the silicon source and the aluminum source,

Washing the aluminosilicate salt to obtain aluminosilicate nanoparticles, and

Drying the aluminosilicate nanoparticles

Containing, a method for producing aluminosilicate nanoparticles is provided.

Hereinafter, a method of manufacturing aluminosilicate nanoparticles according to an embodiment of the present invention will be described.

Unless expressly stated in the specification, terminology is only intended to refer to specific embodiments and is not intended to limit the invention.

The singular forms used in the present specification also include plural forms unless the phrases clearly indicate the opposite.

The meaning of'comprising' as used herein specifies a specific characteristic, region, integer, step, action, element or component, and excludes the addition of another specific characteristic, region, integer, step, action, element, or component. It is not.

According to one embodiment of the invention,

Injecting an alkaline silicon source into the reactor,

Injecting an acidic aluminum source including aluminum potassium sulfate and isopropyl alcohol into the reactor and stirring,

Forming an aluminum silicate salt by neutralizing the silicon source and the aluminum source,

Washing the aluminosilicate salt to obtain aluminosilicate nanoparticles, and

Drying the aluminosilicate nanoparticles

Containing, a method for producing aluminosilicate nanoparticles is provided.

As a result of continuous research of the present inventors, in the method of producing aluminosilicate nanoparticles by neutralization reaction between an alkaline silicon source and an acidic aluminum source, aluminum potassium sulfate (AlK(SO ₄ ) ₂ ) and isopropyl alcohol It was confirmed that when the included acidic aluminum source was introduced at an appropriate rate, aluminosilicate nanoparticles having developed mesopores and excellent specific surface area characteristics could be obtained.

The characteristics of the aluminosilicate nanoparticles enable the aluminosilicate nanoparticles to exhibit excellent dispersibility in the rubber composition, while improving workability and productivity in the rubber molding process.

According to an embodiment of the invention, the step of introducing an alkaline silicon source into the reactor is performed.

The configuration of the reactor is not particularly limited, and a reaction flask or reaction tube for inorganic synthesis equipped with a stirring means may be used.

The alkaline silicon source is an alkaline solution with a pH greater than 7 containing a water-soluble silicon salt.

As the water-soluble silicone salt, a silicone compound capable of exhibiting an alkalinity of more than pH 7 in an aqueous solution may be used without particular limitation. Preferably, the water-soluble silicon salt may be one or more compounds selected from the group consisting of sodium silicate (Na ₂ SiO ₃ ) and potassium silicate (K ₂ SiO ₃ ).

Subsequently, an acidic aluminum source including aluminum potassium sulfate and isopropyl alcohol is added to the reactor and agitated.

The aluminum source is a solution having a hydrogen ion concentration of less than pH 7.

In order to express all the characteristics according to the present invention, an aqueous solution including aluminum potassium sulfate and isopropyl alcohol may be preferably used as the aluminum source.

The isopropyl alcohol contained in the aluminum source enables the formation of aluminosilicate nanoparticles having excellent specific surface area properties and developed mesopores in the neutralization reaction between the silicon source and the aluminum source.

According to an embodiment of the present invention, the isopropyl alcohol may be included in an amount of less than 8.0% (v/v) with respect to the acidic aluminum source. Here, the content (v/v) of the isopropyl alcohol refers to the volume (v) of isopropyl alcohol present in the unit volume (v) of the acidic aluminum source.

Specifically, the isopropyl alcohol is less than 8.0% (v/v), or 7.9% (v/v) or less, or 7.0% (v/v) or less, or 6.5% (v/v) or less with respect to the acidic aluminum source. v) or less, or 6.0% (v/v) or less, or 5.5% (v/v) or less; And 1.0% (v/v) or higher, or 2.0% (v/v) or higher, or 3.0% (v/v) or higher, or 4.0% (v/v) or higher, or 4.5% (v/v) or higher. Can be included.

Preferably, the isopropyl alcohol is 1.0% (v/v) or more and less than 8.0% (v/v), or 2.0 to 7.9% (v/v), or 3.0 to 7.0% ( v/v), or 4.0 to 6.5% (v/v), or 4.0 to 6.0% (v/v), or 4.5 to 5.5% (v/v).

In order to sufficiently express the effect of the addition of isopropyl alcohol to the acidic aluminum source, the isopropyl alcohol is preferably contained in an amount of 1.0% (v/v) or more with respect to the acidic aluminum source. .

However, when isopropyl alcohol is added in an excessive amount to the acidic aluminum source, the specific surface area of the aluminosilicate nanoparticles formed by the neutralization reaction and the volume of mesopores may decrease. Therefore, the isopropyl alcohol is preferably contained less than 8.0% (v/v) with respect to the acidic aluminum source.

According to an embodiment of the invention, the acidic aluminum source is preferably introduced into the reactor at a rate of 5 to 30 ml/min.

Specifically, the introduction rate of the acidic aluminum source is 5 ml/min or more or 7.5 ml/min or more; And it may be 30 ml/min or less, or 25 ml/min or less, or 20 ml/min or less, or 15 ml/min or less.

Preferably, the introduction rate of the acidic aluminum source is 5 to 30 ml/min, or 5 to 25 ml/min, or 7.5 to 20 ml/min, or 7.5 to 15 ml/min.

If the rate of introduction of the silicon source is too slow, the specific surface area of the aluminosilicate nanoparticles is smaller than the target level, and thus it may be difficult to develop abrasion resistance, wet grip and rolling resistance characteristics as a rubber reinforcing material. In addition, the prolonged process time may reduce productivity. Therefore, the silicon source is preferably added at a rate of 5 ml/min or more.

However, when the injection speed of the aluminum source is too fast, the size of the generated particles may be reduced and the specific surface area may be greater than a target level. When the specific surface area of the particles is too large, agglomeration phenomenon between particles easily occurs in the rubber composition, and the dispersibility of the particles decreases. In addition, it is difficult to obtain a target reinforcement effect, such as loss of wet grip properties of rubber moldings. Therefore, the silicon source is preferably added at a rate of 30 ml/min or less.

The acidic aluminum source is preferably introduced so that the molar ratio (Si/Al) of the silicon atom (Si) in the silicon source and the aluminum atom (Al) in the aluminum source is 2.0 to 6.0.

Specifically, the molar ratio (Si/Al) is 2.0 or more, or 2.5 or more, or 3.0 or more, or 3.5 or more, or 4.0 or more; And it may be 6.0 or less, or 5.5 or less, or 5.0 or less, or 4.5 or less.

In order to be able to produce aluminosilicate nanoparticles having a preferable range of specific surface area properties and abrasion resistance as a rubber reinforcing material for tires, silicon atoms (Si) in the silicon source and aluminum atoms (Al) in the aluminum source in the neutralization reaction ) The molar ratio (Si/Al) is preferably 2.0 or more.

However, when silicon atoms (Si) are included in an excessively high molar ratio in the inorganic source used in the neutralization reaction, the yield of the aluminosilicate nanoparticles, which is the final product, decreases, causing an increase in the cost of the silicon source. Therefore, in the neutralization reaction, the molar ratio (Si/Al) of a silicon atom (Si) in the silicon source and an aluminum atom (Al) in the aluminum source is preferably 6.0 or less.

Subsequently, a step of forming an aluminum silicate salt is performed by a neutralization reaction between the silicon source and the aluminum source.

The neutralization reaction is carried out by stirring the mixture of the alkaline silicon source and the acidic aluminum source, thereby obtaining a reaction solution containing an aluminosilicate salt as a solid content.

The neutralization reaction may be started from a point in time when the reactants are mixed by introducing the acidic aluminum source into a reactor in which the alkaline silicon source is present.

The neutralization reaction is preferably carried out at a temperature of 75 ℃ to 90 ℃.

Specifically, the neutralization reaction is 75 ℃ or more or 80 ℃ or more; And it may be carried out under a temperature of 90 ℃ or less or 85 ℃ or less. Preferably, the neutralization reaction may be carried out at a temperature of 75 to 85 °C or 80 to 85 °C.

When the performing temperature of the neutralization reaction is too low, the inorganic components including the silicon source and the aluminum source are aggregated during the neutralization reaction, making it difficult for the reaction to proceed uniformly. Accordingly, it is difficult to control the particle size of the aluminosilicate nanoparticles finally obtained after the neutralization reaction, and the nanoparticles are tightly agglomerated to form huge secondary particles, resulting in nanoparticles having a target rubber reinforcing effect. Can't. Therefore, the neutralization reaction is preferably carried out under a temperature of 75 ℃ or higher.

However, if the temperature for performing the neutralization reaction is too high, there is a concern that the reaction efficiency may decrease due to boiling of the solvent. Therefore, the neutralization reaction is preferably carried out under a temperature of 90 ℃ or less.

The temperature of the neutralization reaction may be controlled by direct or indirect heating to the reactor.

The mixing ratio of the silicon source and the aluminum source in the neutralization reaction may be determined in consideration of the type of salt contained in each source, the pH of each source, and a preferable pH range of the reaction solution that is a product of the neutralization reaction.

In particular, according to an embodiment of the present invention, it is preferable that the reaction solution, which is a product of the neutralization reaction, has a hydrogen ion concentration of pH 6 or higher, or pH 6 to pH 10, or pH 6 to pH 8.

When the hydrogen ion concentration of the reaction solution is less than pH 6, it is difficult to control the particle size of the aluminosilicate nanoparticles, and the size of the nanoparticles becomes large, so that the target rubber reinforcing effect may not be achieved.

Furthermore, the pH of the reaction solution may affect the pH indicated by the finally obtained aluminosilicate nanoparticles. In addition, the pH indicated by the aluminosilicate nanoparticles may affect the scorch time in the process of blending the nanoparticles into the rubber composition.

The scorch time refers to the time it takes for the heat curing of the rubber composition to start during the rubber molding process. In general, after the heat curing of the rubber composition starts, the flow of the rubber composition in the mold stops and molding such as a press becomes difficult, and therefore an appropriate scorch time is required to secure workability and productivity.

However, if the pH indicated by the aluminosilicate nanoparticles is too low or too high, it is difficult to secure an appropriate scorch time during the rubber molding process, and additional measures to prevent scorch or addition of a thermal curing retardant are required. The workability and productivity of the molding may decrease.

For example, if the pH indicated by the aluminosilicate nanoparticles is too low, the scorch time rapidly slows during rubber compounding, and if the pH is too high, the scorch time may rapidly increase.

Specifically, the pH of the nanoparticles has a great influence on the reactivity of the components to be mixed together in the rubber compounding process. In particular, it accelerates or alleviates the reaction rate of the amine-based functional group. That is, when the pH of the nanoparticles is low, the reactivity of the amine group decreases, and when the pH of the nanoparticles is high, the reactivity of the amine group is promoted. If the reactivity is too accelerated in the rubber compounding process, problems may arise in product molding, and if the reactivity is too low, productivity may be reduced.

Therefore, in order to ensure an appropriate scorch time in the rubber molding process in which the aluminosilicate nanoparticles are applied as a rubber reinforcing material, the neutralization reaction is performed in the reaction solution containing the aluminosilicate salt at pH 6 to pH 10. It is preferable that it is performed to have.

Subsequently, a step of washing the aluminosilicate salt to obtain aluminosilicate nanoparticles is performed.

In the washing step, aluminosilicate salt, which is a solid component, is recovered from the reaction solution obtained through the neutralization reaction, and then dispersed in water such as distilled water and deionized water, and washed several times to obtain aluminosilicate nanoparticles.

The washed aluminosilicate nanoparticles may exhibit a hydrogen ion concentration of pH 6 to pH 10.

Then, the step of drying the washed aluminosilicate nanoparticles is performed. The drying may be performed for 1 to 48 hours at a temperature of 20 to 150 °C.

If necessary, conventional steps such as pulverizing and classifying the obtained aluminosilicate nanoparticles may be further performed.

Meanwhile, the aluminosilicate nanoparticles obtained by the above-described manufacturing method are amorphous particles having the composition of the following formula (1):

[Formula 1]

[(M _a Al _x O _2x )·(Si _y O _2y )]·m(H ₂ O)

In Formula 1,

M is an element selected from the group consisting of Li, Na, K, Rb, Cs, Be, Fr, Ca, Zn, and Mg, or an ion thereof;

a> 0, x> 0, y> 0, and m> 0;

3.0 ≤ y/x ≤ 20.0,

a/x <1.2.

The aluminosilicate nanoparticles contain an alkali metal or an ion thereof as a metal element (M) or an ion thereof, and satisfy a composition of 3.0≦y/x≦20.0 and a/x<1.2.

Specifically, in Formula 1, y/x is 3.0 or more, or 3.5 or more, or 4.0 or more, or 4.1 or more, or 4.2 or more; And it may be 20.0 or less, or 15.0 or less, or 10.0 or less, or 5.0 or less, or 4.7 or less. Preferably, the y/x may be 3.0 to 20.0, or 3.5 to 15.0, or 4.0 to 10.0, or 4.1 to 5.0, or 4.2 to 4.7.

Further, specifically, in Formula 1, a/x is less than 1.2, or 1.1 or less, or 1.0 or less; And 0.5 or more, or 0.6 or more, or 0.7 or more, or 0.8 or more, or 0.85 or more. Preferably, the a/x may be 0.5 to 1.1, or 0.6 to 1.0, or 0.8 to 1.0, or 0.85 to 1.0.

The aluminosilicate nanoparticles obtained by the above manufacturing method are amorphous.

In particular, the aluminosilicate nanoparticles have a full width at half maximum (FWHM) of 3.0 in the range of 20° to 37° of 2θ in the data graph obtained by X-ray diffraction (XRD). By satisfying the range of ° to 9.0 °, it can exhibit excellent physical properties as a reinforcing material.

Specifically, the half width (FWHM) of the maximum peak is 3.0° or more, or 4.0° or more, or 5.0° or more, or 6.0° or more, or 7.0° or more. In addition, preferably, the half width (FWHM) of the maximum peak is 9.0 or less, 8.0° or less, or 7.6° or less. Preferably, the half width (FWHM) of the maximum peak is 3.0° to 9.0°, or 4.0° to 8.0°, or 5.0° to 8.0°, or 6.0° to 8.0°, or 7.0° to 7.6°, or 7.5 It can be from ° to 7.6 °.

The half width (FWHM) of the maximum peak is a numerical value of the peak width at a position of 1/2 of the maximum peak intensity in the range of 20° to 37° of 2θ obtained from X-ray diffraction of the aluminosilicate nanoparticles.

The unit of the half width (FWHM) of the maximum peak may be expressed in degrees (°), which is a unit of 2θ, and the value of the half width may be smaller as a compound having high crystallinity.

In addition, the aluminosilicate nanoparticles may exhibit a maximum peak intensity (I _max ) in a 2θ range of 26° to 31° in a data graph obtained by X-ray diffraction (XRD).

Specifically, the aluminosilicate nanoparticles are 26° or more; In addition, the maximum peak intensity (I _max ) may be expressed in a 2θ range of 31° or less, 30° or less, 29° or less, 28° or less, or 27° or less of 2θ. Preferably, the aluminosilicate nanoparticles may exhibit the maximum peak intensity (I _max ) in a 2θ range of 26° to 31°, or 26° to 29°, or 26° to 27°.

For reference, amorphous silica is seen the I _max in the 2θ range of 20 ° to 25 °, amorphous alumina is generally visible to I _max in the 2θ range of 30 ° to 40 °.

According to an embodiment of the invention, the aluminosilicate nanoparticles obtained by the above production method have an average primary particle diameter of 10 to 50 nm.

Specifically, the aluminosilicate nanoparticles are 10 nm or more, or 15 nm or more, or 20 nm or more; And it may have an average primary particle diameter of 50 nm or less, 45 nm or less, 40 nm or less, or 35 nm or less.

In general, the smaller the particle diameter of the rubber reinforcement material, the better the reinforcing effect can be exhibited. However, the smaller the particle diameter of the rubber reinforcing material, the more easily agglomeration between particles in the rubber composition occurs, resulting in poor dispersibility. When such agglomeration becomes severe, phase separation between the rubber reinforcement material and the rubber components may occur, and as a result, the workability of the tire decreases, and it may be difficult to obtain a target reinforcing effect.

According to an embodiment of the invention, the aluminosilicate nanoparticles obtained by the above manufacturing method have a Brunner-Emmett-Teller specific surface area (S _BET ) of 150 to 300 m ² /g and 100 to 250 by nitrogen adsorption/desorption analysis. It has an external specific surface area (S _EXT ) of m ² /g.

As a non-limiting example, the measurement of the specific surface area of the aluminosilicate nanoparticles may be performed according to a standard test method such as ASTM D3663 using a general particle analyzer.

Specifically, the S _BET is 150 m ² /g or more, or 160 m ² /g or more, or 165 m ² /g or more; And 300 m ² /g or less, or 280 m ² /g or less, or 260 m ² /g or less, or 240 m ² /g or less, or 220 m ² /g or less, or 210 m ² /g or less. Preferably, the S _BET is 150 to 300 m ² /g, or 160 to 280 m ² /g, or 165 to 240 m ² /g, or 165 to 210 m ² /g.

Further, specifically, the S _EXT is 100 m ² /g or more, or 110 m ² /g or more, or 120 m ² /g or more; And it is 250 m ² /g or less, 200 m ² /g or less, or 180 m ² /g or less, or 160 m ² /g or less. Preferably, the S _EXT is 100 to 250 m ² /g, or 110 to 200 m ² /g, or 110 to 180 m ² /g, or 120 to 160 m ² /g.

In addition, the ratio of the S _BET and S _EXT (S _EXT /S _BET ) of the aluminosilicate nanoparticles may be 0.6 to 0.8, which may be more advantageous for the expression of various characteristics according to the present invention.

Specifically, the S _EXT /S _BET is 0.60 or more, or 0.70 or more, or 0.72 or more; And it is 0.80 or less, or 0.75 or less. Preferably, S _EXT /S _BET is 0.60 to 0.80, or 0.70 to 0.80, or 0.70 to 0.75, or 0.72 to 0.75.

In particular, the aluminosilicate nanoparticles obtained by the above production method have a mesopore volume (V _meso ) of 0.99 cm ³ /g or more.

In the present specification, mesopore refers to a pore having a pore diameter (d _p ) of 2 nm to 185 nm present on the aluminosilicate nanoparticles. In addition, a pore having a pore diameter (d _p ) of less than 2 nm is defined as a micropore.

Specifically, the mesopore volume (V _meso ) of the aluminosilicate nanoparticles is 0.99 cm ³ /g or more, or 1.00 cm ³ /g or more, or 1.01 cm ³ /g or more, 1.02 cm ³ /g or more, or Not less than 1.03 cm ³ /g; And it may be 1.50 cm ³ /g or less, or 1.40 cm ³ /g or less, or 1.35 cm ³ /g or less.

Preferably, the mesopore volume (V _meso ) of the aluminosilicate nanoparticles is 0.99 cm ³ /g to 1.50 cm ³ /g, or 1.00 cm ³ /g to 1.40 cm ³ /g, or 1.01 cm ³ / g to 1.40 cm ³ /g, or 1.02 cm ³ /g to 1.35 cm ³ /g, or 1.03 cm ³ /g to 1.35 cm ³ /g.

The mesopore volume (V _meso ) can be measured according to a standard test method such as ASTM D4222 using a general particle analyzer. For example, the mesopore volume (V _meso ) may be a value calculated from a Barrett-Joiner-Halenda (BJH) plot of the aluminosilicate nanoparticles.

According to the above manufacturing method, aluminosilicate nanoparticles having excellent specific surface area properties and developed mesopores are provided. The characteristics of the aluminosilicate nanoparticles enable the aluminosilicate nanoparticles to exhibit excellent dispersibility in the rubber composition and to exhibit improved workability and productivity in the rubber molding process.

1 is a scanning electron microscopy (SEM) image of the aluminosilicate nanoparticles prepared in Example 1. FIG.
2 is an SEM image of the aluminosilicate nanoparticles prepared in Example 2.
3 is an SEM image of the aluminosilicate nanoparticles prepared in Comparative Example 1.
4 is an SEM image of the aluminosilicate nanoparticles prepared in Comparative Example 2.
5 is an SEM image of the aluminosilicate nanoparticles prepared in Comparative Example 3.
6 is an SEM image of the aluminosilicate nanoparticles prepared in Comparative Example 4.
7 is a SEM image of the aluminosilicate nanoparticles prepared in Comparative Example 5.
8 is an SEM image of the aluminosilicate nanoparticles prepared in Comparative Example 6.
9 is a Barrett-Joiner-Halenda (BJH) plot for aluminosilicate nanoparticles prepared in Examples and Comparative Examples (d _p = pore diameter (nm); V _p = pore volume (cm ³ /g)) ).
10 is a graph showing the results of X-ray diffraction analysis of aluminosilicate nanoparticles prepared in Examples and Comparative Examples.

Hereinafter, preferred embodiments are presented to aid the understanding of the present invention. However, the following examples are only for illustrating the present invention, and the present invention is not limited thereto.

Example One

A 0.005 M sodium silicate (Na ₂ SiO ₃ ) aqueous solution was prepared as a silicon source.

As an aluminum source, an aqueous solution containing 0.0025 M aluminum potassium sulfate (AlK(SO ₄ ) ₂ ) and isopropyl alcohol was prepared. Isopropyl alcohol was added in an amount of 5.0% (v/v) relative to the aluminum source.

1117.82 mL of the silicon source was added to a reactor (round bottom flask of 2000 mL capacity) at room temperature (25° C.).

In the reactor in which the silicon source is present, the aluminum source was added. The aluminum source was added at a rate of 15.0 ml/min until the molar ratio (Si/Al) of silicon atoms (Si) and aluminum atoms (Al) in the reactor became 4.4.

The neutralization reaction was performed by mixing for 10 minutes at 500 rpm using an overhead stirrer while heating so that the temperature of the aqueous solution in the reactor was maintained at 80°C.

A reaction solution containing an aluminosilicate salt was obtained by the above neutralization reaction. The aluminosilicate salt was added to distilled water at room temperature, stirred for 12 hours, and washed by centrifugation. The washed aluminosilicate salt was dried in an oven at 70° C. for 24 hours to obtain aluminosilicate nanoparticles.

Example 2

A 0.005 M sodium silicate (Na ₂ SiO ₃ ) aqueous solution was prepared as a silicon source.

As an aluminum source, an aqueous solution containing 0.0025 M aluminum potassium sulfate (AlK(SO ₄ ) ₂ ) and isopropyl alcohol was prepared. Isopropyl alcohol was added in an amount of 5.0% (v/v) relative to the aluminum source.

1117.82 mL of the silicon source was added to a reactor (round bottom flask of 2000 mL capacity) at room temperature (25° C.).

In the reactor in which the silicon source is present, the aluminum source was added. The aluminum source was added at a rate of 7.5 ml/min until the molar ratio (Si/Al) of silicon atoms (Si) and aluminum atoms (Al) in the reactor became 4.4.

The neutralization reaction was performed by mixing for 10 minutes at 500 rpm using an overhead stirrer while heating so that the temperature of the aqueous solution in the reactor was maintained at 80°C.

A reaction solution containing an aluminosilicate salt was obtained by the above neutralization reaction. The aluminosilicate salt was added to distilled water at room temperature, stirred for 12 hours, and washed by centrifugation. The washed aluminosilicate salt was dried in an oven at 70° C. for 24 hours to obtain aluminosilicate nanoparticles.

Comparative example One

Aluminosilicate nanoparticles were obtained in the same manner as in Example 1, except that 0.0025 M aluminum potassium sulfate (AlK(SO ₄ ) ₂ ) aqueous solution was used as the aluminum source.

Comparative example 2

Aluminosilicate nanoparticles were obtained in the same manner as in Example 2, except that 0.0025 M aluminum potassium sulfate (AlK(SO ₄ ) ₂ ) aqueous solution was used as the aluminum source.

Comparative example 3

Aluminosilicate nanoparticles were obtained in the same manner as in Example 1, except that 8.0% (v/v) of isopropyl alcohol was added to the aluminum source as the aluminum source.

Comparative example 4

Aluminosilicate nanoparticles were obtained in the same manner as in Example 1, except that 10.0% (v/v) of isopropyl alcohol was added to the aluminum source as the aluminum source.

Comparative example 5

Aluminosilicate nanoparticles were obtained in the same manner as in Example 1, except that an aluminum source to which ethyl alcohol was added in place of isopropyl alcohol was used.

Comparative example 6

Aluminosilicate nanoparticles were obtained in the same manner as in Example 1, except that an aluminum source to which methyl alcohol was added in place of isopropyl alcohol was used.

Test example One

The composition of the aluminosilicate nanoparticles according to the above Examples and Comparative Examples was confirmed using X-ray fluorescence (XRF, Rigaku zsx primus II, wavelength dispersive type). The results are shown in Table 1 below. The XRF measurement was performed using a Rh target, and the particle powder was mounted on a holder having a diameter of 30 mm.

Composition (Chemical Formula 1) M a x y K Na Example 1 0.51 0.34 0.85 1.00 4.25 Example 2 0.55 0.43 0.98 1.00 4.62 Comparative Example 1 0.53 0.37 0.90 1.00 4.46 Comparative Example 2 0.52 0.41 0.93 1.00 4.35 Comparative Example 3 0.54 0.43 0.96 1.00 4.57 Comparative Example 4 0.54 0.44 0.98 1.00 4.65 Comparative Example 5 0.52 0.42 0.94 1.00 4.47 Comparative Example 6 0.53 0.43 0.96 1.00 4.50

Test example 2

Aluminosilicate nanoparticles according to the Examples and Comparative Examples were photographed using scanning electron microscopy (SEM). The photographed SEM images are shown in Fig. 1 (Example 1), Fig. 2 (Example 2), Fig. 3 (Comparative Example 1), Fig. 4 (Comparative Example 2), Fig. 5 (Comparative Example 3), and Fig. 6 (Comparative Example) 4), Fig. 7 (Comparative Example 5), and Fig. 8 (Comparative Example 6).

Test example 3

Using an X-ray diffraction analyzer (Bruker AXS D4-Endeavor XRD), under an applied voltage of 40 kV and an applied current of 40 mA, X-ray diffraction analysis was performed on the aluminosilicate nanoparticles of the Examples and Comparative Examples. I did. The results are shown in Table 2 and FIG. 10 below.

In performing the X-ray diffraction analysis, the measured range of 2θ was 10° to 90°, and the scan was performed at an interval of 0.05°. At this time, a variable divergence slit 6 mm was used as the slit, and a large PMMA holder (diameter = 20 mm) was used to eliminate background noise caused by the PMMA holder.

In the data graph obtained by X-ray diffraction, the full width at half maximum (FWHM) of about 29° peak, which is the maximum peak in the range of 20° to 37° of 2θ, was calculated.

FWHM (°) I _max (°) Crystal form Example 1 7.578 26.560 Amorphous Example 2 7.501 26.747 Amorphous Comparative Example 1 7.866 27.682 Amorphous Comparative Example 2 8.172 27.121 Amorphous Comparative Example 3 7.951 26.671 Amorphous Comparative Example 4 8.018 27.027 Amorphous Comparative Example 5 7.410 27.017 Amorphous Comparative Example 6 7.655 26.673 Amorphous

Test example 4

(1) Nitrogen adsorption/desorption Brunner-Emit-Teller specific surface area (S _BET ) for aluminosilicate nanoparticles according to the Examples and Comparative Examples using a specific surface area analyzer (BEL Japan Inc., BELSORP-max) And the external specific surface area (S _EXT ) excluding micropores of less than 2 nm was measured. The measurement was performed according to the standard measurement method of ASTM D3663. The measured values are shown in Table 3 below.

(2) A specific surface area analyzer (BEL Japan Inc., BELSORP-max) was used to analyze the pore size distribution of the aluminosilicate nanoparticles according to the Examples and Comparative Examples. The analysis was performed according to the standard measurement method of ASTM D4222. The Barrett-Joiner-Halenda (BJH) plot obtained through the above analysis is shown in FIG. 9 (d _p = pore diameter (nm); V _p = pore volume (cm ³ /g)). The volume of mesopores (V _meso ) having a pore diameter (d _p ) of 2 nm to 185 nm calculated from the BJH plot is shown in Table 3 below.

S _BET
(m ² /g) S _EXT
(m ² /g) S _EXT /S _BET V _meso
(cm ³ /g) Example 1 209.43 152.35 0.73 1.3184 Example 2 169.63 122.10 0.72 1.0311 Comparative Example 1 202.21 150.34 0.74 1.0488 Comparative Example 2 170.27 122.84 0.72 0.7885 Comparative Example 3 178.26 124.85 0.70 0.8621 Comparative Example 4 198.23 131.54 0.66 0.5633 Comparative Example 5 202.95 144.26 0.71 0.9786 Comparative Example 6 180.25 128.29 0.71 0.6063

Referring to Table 3, the aluminosilicate nanoparticles prepared by the method of the Examples above have a specific surface area value similar to that of the aluminosilicate nanoparticles prepared by the method of the Comparative Examples, but are more developed meso. It is confirmed to have pores.

In particular, in Comparative Examples 1 and 2 in which isopropyl alcohol was not added, it was confirmed that the mesopore volume (V _meso ) was lower than in Examples 1 and 2.

In addition, in Comparative Examples 3 and 4, as isopropyl alcohol was added in an excessive amount, it was confirmed that the mesopore volume was significantly lower than that of the aluminosilicate nanoparticles according to Example 1.

In addition, in Comparative Examples 5 and 6 in which methyl alcohol or ethyl alcohol was used, it was confirmed that the mesopore volume was significantly lower than that of the aluminosilicate nanoparticles according to Example 1.

Claims (9)

Injecting an alkaline silicon source into the reactor,
Injecting an acidic aluminum source including aluminum potassium sulfate and isopropyl alcohol into the reactor and stirring,
Forming an aluminum silicate salt by neutralizing the silicon source and the aluminum source,
Washing the aluminosilicate salt to obtain aluminosilicate nanoparticles, and
Drying the aluminosilicate nanoparticles
Containing, the method for producing aluminosilicate nanoparticles.
The method of claim 1,
The isopropyl alcohol is contained in an amount of less than 8.0% (v/v) with respect to the acidic aluminum source, a method for producing aluminosilicate nanoparticles.
The method of claim 1,
The acidic aluminum source is introduced into the reactor at a rate of 5 to 30 ml/min, a method for producing aluminosilicate nanoparticles.
The method of claim 1,
The alkaline silicon source is at least one compound selected from the group consisting of sodium silicate and potassium silicate, a method for producing aluminosilicate nanoparticles.
The method of claim 1,
The acidic aluminum source is introduced so that a molar ratio (Si/Al) of a silicon atom (Si) in the silicon source and an aluminum atom (Al) in the aluminum source is 2.0 to 6.0, the production of aluminosilicate nanoparticles Way.
The method of claim 1,
The neutralization reaction is carried out under a temperature of 75 ℃ to 90 ℃, the method of producing aluminosilicate nanoparticles.
The method of claim 1,
The aluminosilicate nanoparticles are amorphous particles having a composition of the following formula (1), a method for producing aluminosilicate nanoparticles:
[Formula 1]
[(M _a Al _x O _2x )·(Si _y O _2y )]·m(H ₂ O)
In Formula 1,
M is an element selected from the group consisting of Li, Na, K, Rb, Cs, Be, Fr, Ca, Zn, and Mg, or an ion thereof;
a> 0, x> 0, y> 0, and m>0;
3.0 ≤ y/x ≤ 20.0,
a/x <1.2.
The method of claim 1,
The mesopore volume (V _meso ) having a pore diameter (d _p ) of 2 nm to 185 nm of the aluminosilicate nanoparticles is 0.99 cm ³ /g or more,
The mesopore volume (V _meso ) is a value calculated from a Barrett-Joiner-Halenda (BJH) plot of the aluminosilicate nanoparticles measured according to ASTM D4222,
Method for producing aluminosilicate nanoparticles.
The method of claim 1,
The aluminosilicate nanoparticles have a Brunner-Emmett-Teller specific surface area (S _BET ) of 150 to 300 m ² /g and an external ratio of 100 to 250 m ² /g by nitrogen adsorption/desorption analysis according to ASTM D3663. A method for producing aluminosilicate nanoparticles having a surface area (S _EXT ) and satisfying 0.7 ≤ S _EXT /S _BET ≤ 0.8.

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