Method for producing high-strength ceramic particles and method for producing micro-porous spherical particles for aerosol generator using Benard cell phenomenon

Abstract

The embodiments relate to a method for manufacturing high-strength ceramic particles and a method for manufacturing micro-porous spherical particles for an aerosol generator using the Bernal cell phenomenon. 【Solution means】The embodiments provide a method for manufacturing high-strength ceramic particles, characterized by including a first step of mixing a silicate powder combined with metal ions and a glass powder for low-temperature sintering, a second step of adding a polymer and a dispersant to the mixed powder to produce ceramic granules, a third step of pressure-molding the ceramic granules, and a fourth step of sintering the molded body.

Description

Technical Field

[0001] The embodiment relates to a method for manufacturing high-strength ceramic particles.

Background Art

[0002] FIG. 1 is a view of the vaporization section of an aerosol generator according to the prior art as seen from above, and FIG. 2 is a view of the vaporization section of an aerosol generator according to the prior art as seen from below.

[0003] When an aerosol generator employs a wick and a coil assembly as a vaporization section, due to the heat transfer rate difference between the wick and the coil assembly, there is a risk of local carbonization of the liquid and the wick. The vaporization section of the aerosol generator shown in FIGS. 1 and 2 was developed to improve such problems. The vaporization section of the fine particle generator according to the first embodiment of the present invention includes a porous ceramic 10 that absorbs and supports a liquid, and a heating element 16 that is attached to the lower surface of the porous ceramic 10 and heats and vaporizes the liquid. A power line 14 for applying an electric current to the heating element 10 may be connected to the heating element 16 attached to the surface of the porous ceramic 10.

[0004] The porous ceramic 10 includes a concave groove 12 that serves as a water storage tank for storing the liquid in the center. By providing a water storage tank capable of storing the liquid, there is an advantage that the liquid can be stably and continuously supplied into the pores of the porous ceramic 10.

[0005] Also, in the porous ceramic 10, the movement of the liquid is performed at a low speed, the movement of the aerosol at a high temperature is smooth, and each pore of the porous ceramic 10 can be connected to form an air passage through which the aerosol passes.

[0006] At this time, as the specific surface area of the porous ceramic 10 increases, the amount of liquid absorbed by the porous ceramic 10 increases, and the amount of atomization can be increased.

[0007] Therefore, in order to be used as a vaporization unit for an aerosol generator, there is a need to develop a manufacturing method for improving the specific surface area of the porous ceramic 10.

Summary of the Invention

Problems to be Solved by the Invention

[0008] The purpose of the examples is to provide a method for manufacturing high-strength ceramic particles.

[0009] Moreover, the purpose of the examples is to provide a method for manufacturing micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon so that the specific surface area of the porous particles increases.

Means for Solving the Problems

[0010] The examples include a first step of mixing silicate powder combined with metal ions and glass powder for low-temperature sintering, a second step of adding a polymer and a dispersant to the mixed powder to produce ceramic granules, a third step of pressure-molding the ceramic granules, and a fourth step of sintering the molded body, and provide a method for manufacturing high-strength ceramic particles, which is characterized by increasing the specific surface area by inducing defects on the surface.

[0011] Moreover, in another aspect of the examples, the silicate powder contains one or more metal ions selected from Mg, Al, Zr, Li, Ba, MgAl, Na, and Ca, and provides a method for manufacturing high-strength ceramic particles.

[0012] Moreover, in another aspect of the examples, the silicate powder combined with metal ions has a specific surface area measured by the BET method of 20 to 500 m 2 / g, and provides a method for manufacturing high-strength ceramic particles.

[0013] In another aspect of the embodiment, there is provided a method for manufacturing high-strength ceramic particles, characterized in that the average particle diameter of the silicate powder combined with metal ions is 5 to 500 μm.

[0014] In another aspect of the embodiment, there is provided a method for manufacturing high-strength ceramic particles, characterized in that the glass powder for low-temperature sintering is one or more of amorphous glass powder and ceramic powder for low-temperature sintering.

[0015] In another aspect of the embodiment, there is provided a method for manufacturing high-strength ceramic particles, characterized in that the glass powder for low-temperature sintering has any one of plate shape, fiber shape, and polygonal shape.

[0016] In another aspect of the embodiment, there is provided a method for manufacturing high-strength ceramic particles, characterized in that the glass powder for low-temperature sintering has an appropriate sintering temperature range of 600 to 1200 °C.

[0017] In another aspect of the embodiment, there is provided a method for manufacturing high-strength ceramic particles, characterized in that the average particle diameter of the glass powder for low-temperature sintering is 0.5 to 50 μm.

[0018] In another aspect of the embodiment, there is provided a method for manufacturing high-strength ceramic particles, characterized in that the glass powder for low-temperature sintering is mixed in an amount of 1 to 500 parts by weight with respect to the silicate powder combined with metal ions.

[0019] In another aspect of the embodiment, there is provided a method for manufacturing high-strength ceramic particles, characterized in that the polymer polymer added in the second step is one or more substances selected from polyvinyl alcohol, polyvinyl acetate, polyethylene, polyvinyl butylene, polypropylene, polyvinyl chloride, polyacrylic, polyacrylamide, guar gum, gelatin, and natural rubber.

[0020] In another aspect of the embodiment, a method for manufacturing high-strength ceramic particles is provided, characterized in that the dispersant added in the second step is a wetting dispersant.

[0021] In another aspect of the embodiment, a method for manufacturing high-strength ceramic particles is provided, characterized in that the average particle size of the ceramic granules produced in the second step is 50 to 1000 μm.

[0022] In another aspect of the embodiment, a method for manufacturing high-strength ceramic particles is provided, characterized in that the sintering in the fourth step is carried out in a temperature range of 600 to 1200 °C.

[0023] In another aspect of the embodiment, a method for manufacturing high-strength ceramic particles is provided, characterized in that a ceramic core-shell structure is formed by the surface melting and necking phenomenon of the low-temperature sintering glass powder during the sintering process of the fourth step.

[0024] In another aspect of the embodiment, a method for manufacturing high-strength ceramic particles is provided, characterized in that the high-strength ceramic particles after the sintering process of the fourth step are a porous structure.

[0025] In another aspect of the embodiment, a method for manufacturing micro-porous spherical particles for an aerosol generator using the Bernal cell phenomenon is provided, including the steps of dispersing a silicate powder and a binder combined with metal ions in a first solvent to produce a first dispersion solution, dispersing an additive in a second solvent and stirring to produce a second dispersion solution, mixing the first dispersion solution and the second dispersion solution and stirring to produce a mixed slurry, and spray-drying the mixed slurry.

[0026] Also, in another aspect of the embodiment, the metal silicate powder contains one or more metal ions selected from Mg, Al, Zr, Li, Ba, MgAl, Na, and Ca, and provides a method for producing microporous spherical particles for an aerosol generator using the Benard cell phenomenon.

[0027] Also, in another aspect of the embodiment, the metal silicate powder is dispersed at 5 to 40 wt% with respect to the first solvent, and provides a method for producing microporous spherical particles for an aerosol generator using the Benard cell phenomenon.

[0028] Also, in another aspect of the embodiment, the binder used for producing the first dispersion solution is one or more selected from polyvinyl alcohol, polyvinyl acetate, polyethylene, polyvinyl butylene, polypropylene, polyvinyl chloride, polyacrylic, polyacrylamide, guar gum, gelatin, and natural rubber, and provides a method for producing microporous spherical particles for an aerosol generator using the Benard cell phenomenon.

[0029] Also, in another aspect of the embodiment, the first solvent contains one or more selected from water, ethanol, toluene, IPA, and acetone, and provides a method for producing microporous spherical particles for an aerosol generator using the Benard cell phenomenon.

[0030] Also, in another aspect of the embodiment, the first solvent is used at 70 to 220 wt% with respect to the weight of the metal silicate, and provides a method for producing microporous spherical particles for an aerosol generator using the Benard cell phenomenon.

[0031] Also, in another aspect of the embodiment, the additive used for producing the first dispersion solution contains a high-boiling solvent such as mineral spirit or xylene, and provides a method for producing microporous spherical particles for an aerosol generator using the Benard cell phenomenon.

[0032] In another aspect of the embodiment, there is provided a method for producing micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon, characterized in that the additive is added in an amount of 0.5 to 10 wt% based on the metal silicate.

[0033] In another aspect of the embodiment, there is provided a method for producing micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon, characterized in that the second solution contains one or more selected from water, ethanol, toluene, IPA, and acetone.

[0034] In another aspect of the embodiment, there is provided a method for producing micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon, characterized in that the second solvent used for producing the second dispersion solution is contained in an amount of 5 to 30 wt% based on the metal silicate.

[0035] In another aspect of the embodiment, there is provided a method for producing micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon, characterized in that spray drying uses a disk method and the rotational speed of the disk is adjusted within the range of 500 to 9000 rpm.

[0036] In another aspect of the embodiment, there is provided a method for producing micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon, characterized in that spray drying is performed in a chamber maintained at a temperature of 220 to 300 °C, and the Benard cell phenomenon is induced in the spray drying step to induce defects on the surface of the micro-porous spherical particles.

[0037] In another aspect of the embodiment, there is provided a method for producing micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon, characterized in that the average particle size of the finally produced micro-porous spherical particles is 5 to 500 μm after spray drying.

Advantages of the Invention

[0038] The ceramic moisture absorber produced by the manufacturing method of the high-strength ceramic moisture absorber provided by the embodiment can have high strength due to its core-shell structure.

[0039] In addition, the ceramic heater for an aerosol generator produced by the manufacturing method of the micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon provided by the embodiment can increase the specific surface area of the porous spherical particles by inducing defects on the surface of the particles due to the Benard cell phenomenon. Thereby, the moisture absorption amount of the liquid can be increased, and finally, the generation amount of the aerosol can be increased.

Brief Description of the Drawings

[0040]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0041] Hereinafter, the present invention will be described in more detail based on the drawings.

[0042] FIG. 4 is a flowchart showing a method for manufacturing high-strength ceramic particles according to an embodiment, FIG. 5 is a schematic diagram showing high-strength ceramic particles manufactured by the method for manufacturing high-strength ceramic particles according to the embodiment, and FIG. 6 is a scanning electron micrograph of high-strength ceramic particles manufactured by the method for manufacturing high-strength ceramic particles according to the embodiment.

[0043] The method for manufacturing high-strength ceramic particles according to the embodiment includes a first step (S1) of mixing a silicate powder combined with metal ions and a glass powder for low-temperature sintering, a second step (S2) of adding a polymer and a dispersant to the mixed powder to produce ceramic granules, a third step (S3) of pressure-molding the ceramic granules, and a fourth step (S4) of sintering the molded body.

[0044] At this time, the silicate powder mixed in the first step contains one or more metal ions selected from Mg, Al, Zr, Li, Ba, MgAl, Na, and Ca. Here, the silicate powder combined with metal ions desirably has a specific surface area measured by the BET method of 100 to 450 m 2 / g, and the average particle size of the silicate powder combined with metal ions is desirably 5 to 500 μm. When the average particle size of the silicate powder combined with metal ions exceeds 500 μm, it is difficult to manufacture spherical beads using the spray drying method.

[0045] In addition, in the first step, the glass powder for low-temperature sintering mixed with the silicate powder is desirably one or more of amorphous glass powder and ceramic powder for low-temperature sintering. At this time, the ceramic powder for low-temperature sintering contains Bi2O3, Sb2O5, B2O3, etc.

[0046] At this time, the glass powder for low-temperature sintering can have any one of a plate shape, a fiber shape, and a polygonal shape, and it is desirable that the glass powder for low-temperature sintering has an appropriate sintering temperature range of 600 to 1200°C. Also, it is desirable that the average particle size of the glass powder for low-temperature sintering is 0.5 to 50 μm. The glass powder is added as a kind of liquid sintering agent to promote sintering. When the average particle size of the glass powder for low-temperature sintering is 50 μm or more, the distance between the silicate powders will be too far, so there is a risk of reducing the sintering effect under the same temperature profile. Therefore, it is desirable that the average particle size of the glass powder for low-temperature sintering is 50 μm or less.

[0047] At this time, the glass powder for low-temperature sintering is mixed with the silicate powder bonded with metal ions in an amount of 1 to 500 parts by weight. Here, when 1 to 80 parts by weight of the glass powder for low-temperature sintering is mixed with the silicate powder bonded with metal ions, the occupation ratio of the volume of the silicate powder bonded with metal ions is larger than that of the glass powder for low-temperature sintering, and the hydrophilicity is strong. On the contrary, when 80 to 500 parts by weight of the glass powder for low-temperature sintering is mixed with the silicate powder bonded with metal ions, the occupation ratio of the volume of the glass powder for low-temperature sintering becomes larger than that of the silicate powder, and the hydrophobicity becomes strong.

[0048] According to the use of the high-strength ceramic particles, by adjusting the mixing ratio of the glass powder for low-temperature sintering, it will show hydrophobicity or hydrophilicity. The high-strength ceramic particles produced in this way can be used as they are in the form of beads, or can be used as a heater or a liquid storage part of an aerosol generator in a form where the beads are mixed with a binder and made into a block.

[0049]

Table 1

[0050] Table 1 is a table that organizes the measured values of the flexural strength according to the addition amount of the glass powder for low-temperature sintering. It can be confirmed that the flexural strength increases as the addition amount of the glass powder for low-temperature sintering increases. On the other hand, the polymer added in the second step is desirably one or more substances selected from polyvinyl alcohol, polyvinyl acetate, polyethylene, polyvinyl butylene, polypropylene, polyvinyl chloride, polyacrylic, polyacrylamide, guar gum, gelatin, and natural rubber, and the dispersant is desirably a wetting dispersant.

[0051] The average particle size of the ceramic granules produced in the second step is desirably 50 to 1000 μm.

[0052] On the other hand, the third step is a step of uniaxially or multi-axially pressing the ceramic granules to form them, and compression-molding the ceramic moisture absorber into a desired form.

[0053] The sintering in the fourth step is desirably carried out in a temperature range of 600 to 1200 °C according to the appropriate sintering temperature of the glass powder for low-temperature sintering.

[0054] During the sintering process of the fourth step, a ceramic core-shell structure is formed due to the surface melting and necking phenomenon of the glass powder for low-temperature sintering. That is, by adding the glass powder for low-temperature sintering to the silicate powder in which the high-strength ceramic particles are bonded to metal ions that require high-temperature sintering at 1600 °C or higher, even when sintering at a relatively low temperature of 600 to 1200 °C, there is an advantage of having a fracture strength of 1 Mpa or more.

[0055] On the other hand, the high-strength ceramic particles produced by the method of the example can be installed in an aerosol generator and used for liquid absorption or as a carrier. Also, it can be applied anywhere when a moisture absorber that maintains high strength and must contain a liquid is required.

[0056] FIG. 7 is a flowchart showing a method for manufacturing micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon according to an embodiment, and FIG. 8 is a scanning microscope photograph of a ceramic core-shell structure manufactured by the method for manufacturing micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon according to the embodiment.

[0057] The method for manufacturing micro-porous spherical particles for an aerosol generator using the Benard cell phenomenon according to the embodiment includes the steps of dispersing a silicate powder combined with metal ions and a binder in a first solvent to produce a first dispersion solution, dispersing an additive in a second solvent and stirring to produce a second dispersion solution, mixing the first dispersion solution and the second dispersion solution and stirring to produce a mixed slurry, and spray-drying the mixed slurry.

[0058] At this time, the metal silicate powder preferably contains one or more metal ions selected from Mg, Al, Zr, Li, Ba, MgAl, Na, and Ca, and the metal silicate powder is dispersed at 5 to 40 wt% with respect to the first solvent.

[0059] On the other hand, the binder used for the production of the first dispersion solution is preferably one or more selected from polyvinyl alcohol, polyvinyl acetate, polyethylene, polyvinyl butylene, polypropylene, polyvinyl chloride, polyacrylic, polyacrylamide, guar gum, gelatin, and natural rubber.

[0060] In addition, the first solvent contains one or more selected from water, ethanol, toluene, IPA, and acetone, and it is desirable that the first solvent be used at 70 to 220 wt% with respect to the weight of the metal silicate.

[0061] At this time, the additive used in the production of the first dispersion solution desirably contains a high-boiling solvent such as mineral spirit or xylene, and is desirably added in an amount of 0.5 to 10 wt% based on the metal silicate. Depending on the additive, in the case of an organic additive, when it exceeds 10 wt%, it becomes difficult to maintain the bead form, induces high viscosity, and may reduce workability.

[0062] In addition, the second solution desirably contains one or more selected from water, ethanol, toluene, IPA, and acetone, and is desirably contained in an amount of 5 to 30 wt% based on the metal silicate.

[0063] After mixing and stirring the first dispersion solution and the second dispersion solution to produce a mixed slurry, the mixed slurry is spray-dried to form microporous spherical particles. At this time, the disk method is used for spray drying, and the rotation speed of the disk is desirably adjusted within the range of 500 to 9000 rpm. When the rotation speed of the disk is less than 500 rpm, the effect of centrifugal force is small and the size of the spherical particles is too large. On the contrary, when the rotation speed of the rotating disk exceeds 9000 rpm, the production ratio of spherical particle groups with a size of 20 μm or less increases, and such small spherical particle groups block the surface pores of the heater or the liquid hygroscopic body when manufacturing the heater or the liquid hygroscopic body of the aerosol generator, resulting in a disadvantage that the specific surface area rather decreases. Therefore, the rotation speed of the disk is desirably adjusted within the range of 500 to 9000 rpm.

[0064] The disk onto which the mixed slurry is sprayed rotates in a chamber maintained at a temperature of 220 to 300 °C, inducing the Benard cell phenomenon in the spray drying step, inducing surface defects (cracks) as shown in the photograph of FIG. 8, and increasing the specific surface area of the microporous spherical particles. At this time, the microporous spherical particles have the advantage that they can form micropores without separately adding a pore-forming agent during the manufacturing process. The microporous spherical particles manufactured in this way can increase the specific surface area. Therefore, when manufacturing a heater or a liquid moisture absorber of an aerosol generator using the microporous spherical particles for an aerosol generator using the Benard cell phenomenon according to the examples, the amount of moisture absorbed by the liquid can be increased, and thereby, there is an advantage that the liquid can be vaporized to increase the atomization amount.

Claims

1. A first step involves mixing silicate powder bonded with metal ions and glass powder for low-temperature sintering having an average particle size of 0.5 to 50 μm. A second step involves adding a high-molecular-weight polymer and a dispersant to a mixed powder to produce ceramic granules, The third step involves pressure molding the ceramic granules, The process includes a fourth step of sintering the molded body, The fourth step, sintering, is carried out in a temperature range of 600 to 1200°C. A method for producing high-strength ceramic particles, characterized in that, in the sintering process of the fourth step, a ceramic core-shell structure is formed by surface melting and necking of the glass powder for low-temperature sintering.

2. The method for producing high-strength ceramic particles according to claim 1, characterized in that the silicate powder contains one or more metal ions selected from Mg, Al, Zr, Li, Ba, MgAl, Na, and Ca.

3. Silicate powders bound to metal ions have a specific surface area of ​​20 to 500 m² as measured by the BET method. ２ A method for producing high-strength ceramic particles according to claim 2, characterized in that the amount is / g.

4. A method for producing high-strength ceramic particles according to claim 2, characterized in that the average particle size of the silicate powder bound to metal ions is 5 to 500 μm.

5. The method for producing high-strength ceramic particles according to claim 1, characterized in that the glass powder for low-temperature sintering is one or more of amorphous glass powder and ceramic powder for low-temperature sintering.

6. The method for producing high-strength ceramic particles according to claim 5, characterized in that the glass powder for low-temperature sintering has one of the following shapes: plate shape, fiber shape, and polygonal shape.

7. The method for producing high-strength ceramic particles according to claim 5, characterized in that the glass powder for low-temperature sintering has an appropriate sintering temperature range of 600 to 1200°C.

8. The method for producing high-strength ceramic particles according to claim 1, characterized in that the glass powder for low-temperature sintering is mixed with silicate powder bonded with metal ions in an amount of 1 to 500 parts by weight.

9. The method for producing high-strength ceramic particles according to claim 1, characterized in that the polymer added in the second step is one or more substances selected from polyvinyl alcohol, polyvinyl acetate, polyethylene, polyvinylbutylene, polypropylene, polyvinyl chloride, polyacrylic, polyacrylamide, guar gum, gelatin, and natural rubber.

10. The method for producing high-strength ceramic particles according to claim 1, characterized in that the dispersant added in the second step is a wetting dispersant.

11. The method for producing high-strength ceramic particles according to claim 1, characterized in that the average particle size of the ceramic granules produced in the second step is 50 to 1000 μm.

12. The method for producing high-strength ceramic particles according to claim 1, characterized in that the high-strength ceramic particles obtained through the sintering process in the fourth step are porous structures.

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