A preparation method of a microporous ceramic atomization core

Abstract

The invention relates to the field of ceramic materials, and in particular to a method for preparing a microporous ceramic atomizer core. The method comprises the following steps: mixing ceramic powder, a sintering aid, a bonding component and a pore-forming agent, granulating and injection molding to obtain a green body, heating the green body to remove binder and sintering the green body. The particle size of the pore-forming agent is 1-50 μm, and the pore-forming agent has mesophase asphalt as a core, silica sol as an inner shell and an acrylic polymer as an outer shell. The microporous ceramic atomizer core prepared by the invention has high porosity and mechanical properties, high thermal conductivity and fast oil absorption rate, and is used for making electronic cigarettes, and can provide a better smoking taste.

Description

Technical Field

[0001] The invention relates to the field of ceramic materials, and in particular to a method for preparing a microporous ceramic atomization core. Background Art

[0002] With the development of society and the improvement of people's health awareness, consumers have put forward higher requirements for the safety of smoking. In order to meet the market demand, the substitute of traditional cigarettes - electronic cigarettes have emerged.

[0003] Electronic cigarettes, as the name implies, are electronic cigarettes. They are electronic products that imitate cigarettes and have similar smoke, taste and feel to cigarettes. They are products that turn glycerin, propylene glycol, nicotine and flavors into vapor for users to inhale. The porous ceramic atomizer core in electronic cigarette products plays the role of transmitting and storing tobacco oil and producing atomization.

[0004] The current ceramic atomizer core has an uneven microporous structure and low porosity, which results in poor thermal conductivity and atomization effects, thus affecting the smoking taste. Summary of the invention

[0005] Purpose of the invention: In view of the above technical problems, the present invention proposes a method for preparing a microporous ceramic atomization core.

[0006] The technical solutions adopted are as follows:

[0007] A method for preparing a microporous ceramic atomizing core is as follows:

[0008] The ceramic powder, sintering aid, bonding component and pore-forming agent are mixed, granulated and injection-molded to obtain a green body, and the green body is heated to remove binder and sintered;

[0009] The particle size of the pore-forming agent is 1-50 μm;

[0010] The pore-forming agent has mesophase asphalt as a core, silica sol as an inner shell and acrylic polymer as an outer shell.

[0011] Furthermore, the preparation method of the pore-forming agent is as follows:

[0012] Mix the mesophase asphalt and silica sol evenly, heat the water bath to 60-80°C, stir for 2-5 hours, filter and dry, mix the obtained product with the water-soluble polymer solution, stir at high speed for 30-90 minutes, add the mixed monomer and free radical initiator, heat the water bath to 40-80°C, react for 4-8 hours, filter and dry the obtained product.

[0013] Furthermore, the water-soluble polymer solution is an aqueous solution of hydroxypropyl methylcellulose and / or hydroxyethyl ethylcellulose.

[0014] Further, the mixed monomers include MMA, BA, and St;

[0015] The weight ratio of MMA, BA, and St is 10 - 20:15 - 20:3 - 6.

[0016] Further, the ceramic powder includes alumina powder, aluminum nitride powder, and silicon carbide powder;

[0017] The weight ratio of the alumina powder, aluminum nitride powder, and silicon carbide powder is 10 - 20:3 - 5:1 - 3.

[0018] Further, the sintering aid includes yttrium chloride and lanthanum oxide;

[0019] The weight ratio of the yttrium chloride and lanthanum oxide is 1 - 5:1 - 5.

[0020] Further, the binder component includes PP, paraffin, stearic acid, and bis - tert - butylperoxide diisopropylbenzene;

[0021] The weight ratio of PP, paraffin, stearic acid, and bis - tert - butylperoxide diisopropylbenzene is 50 - 70:20 - 40:2 - 3:0.1 - 1.

[0022] Further, the weight ratio of the ceramic powder, sintering aid, binder component, and pore - forming agent is 1:0.05 - 0.15:0.3 - 0.5:0.1 - 0.2.

[0023] Further, the debinding temperature is 700 - 800 °C, and the debinding time is 1 - 2 h.

[0024] Further, the sintering temperature is 1400 - 1500 °C, and the sintering time is 1 - 3 h.

[0025] Advantages of the present invention:

[0026] The present invention provides a preparation method of a microporous ceramic atomizing core. The pore - forming agent has a three - layer core - shell structure, and the middle - phase asphalt serves as the core. On the one hand, during the heating and sintering process, some small - molecule components and oxidation products such as CO 2 , H 2O will escape and promote pore formation. On the other hand, the residual carbon produced by the sintering of the mesophase asphalt can react with the inner shell of the silica sol to generate silicon carbide and CO, further promoting the formation of holes. The generated silicon carbide can also support the holes and avoid collapse. The acrylic polymer is used as the outer shell, which can protect the mesophase asphalt core and the inner shell of the silica sol, avoid the premature escape of the generated gas, reduce the reaction of the silica sol with alumina, and reduce the generation of mullite phase. Adding diisopropyl di-tert-butyl peroxide to the bonding component can increase the fluidity of the bonding component, so that it can better contact with the remaining components and better form the blank, which can effectively improve the mechanical strength of the microporous ceramic atomization core. Lanthanum oxide and yttrium chloride are used as sintering aids to improve the mechanical strength and thermal conductivity of the microporous ceramic atomization core. The microporous ceramic atomization core prepared by the present invention has high porosity and mechanical properties, high thermal conductivity, and fast oil absorption rate. It is used to make electronic cigarettes and can provide a better smoking taste. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a microscopic morphology of the cross section of the microporous ceramic atomization core prepared in Example 1 of the present invention.

[0028] Figure 2 This is a schematic diagram of the structure of the pore-forming agent prepared in Example 1 of the present invention;

[0029] The numbers in the figure represent:

[0030] 1-nucleus, 2-inner shell, 3-outer shell. DETAILED DESCRIPTION

[0031] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. The techniques not mentioned in the present invention are all referenced to the prior art. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters.

[0032] Embodiment 1:

[0033] A method for preparing a microporous ceramic atomizing core:

[0034] Add 180 g of alumina powder, 40 g of aluminum nitride powder, and 20 g of silicon carbide powder into the ball mill tank of a planetary ball mill. The ball-to-material ratio is 3:1. Using ethanol as the ball milling medium, ball mill at a speed of 400 r / min for 8 h and then dry to obtain ceramic powder. Weigh 7.5 g of yttrium chloride and 7.5 g of lanthanum oxide as sintering aids. Weigh 70 g of PP, 30 g of paraffin wax, 2.5 g of stearic acid, and 0.5 g of diisopropylbenzene peroxide as the binder components. Weigh 25 g of pore former. First, add the binder components into a mixer and heat to melt them, then add the ceramic powder, sintering aids, and pore former. Knead at 200 ± 5 °C for 5 h to obtain a kneaded material. Put the kneaded material into a granulator to granulate and obtain granular material. Add the granular material into an injection molding machine and inject mold at 180 ± 5 °C, a speed of 60 m / s, and a pressure of 120 MPa to obtain a green body. Put the green body into a sagger, sprinkle burn-in powder in the sagger until the green body is completely covered. Put the sagger and the green body together into a sintering furnace. First, heat at a heating rate of 5 °C / min to 750 °C, keep warm and degrease for 2 h, then heat at a heating rate of 0.25 °C / min to 1480 °C, keep warm and sinter for 2 h, and naturally cool to room temperature and then take out of the furnace.

[0035] Among them, the particle size of the pore former is 1 - 50 μm. Using mesophase pitch as the core 1, silica sol as the inner shell 2, and acrylate polymer as the outer shell 3, the preparation method is as follows:

[0036] Mix 50 g of mesophase pitch evenly with 500 mL of 30% alkaline silica sol, heat in a water bath to 80 °C, stir for 4 h, then filter and dry. Mix the obtained product with 3 L of an aqueous solution of hydroxyethyl ethyl cellulose (10 wt%). After high-speed stirring for 60 min, add the mixed monomers (the weights of MMA, BA, and St are 5 g: 8 g: 2 g respectively) and 0.01 g of AIBN, heat in a water bath to 70 °C and react for 8 h, then filter, and dry the obtained product.

[0037] Example 2:

[0038] A preparation method of a microporous ceramic atomization core:

[0039] Add 200 g of alumina powder, 50 g of aluminum nitride powder, and 30 g of silicon carbide powder into the ball milling tank of a planetary ball mill. The ball-to-material ratio is 3:1. Using ethanol as the ball milling medium, ball mill at a speed of 400 r / min for 8 h and then dry to obtain ceramic powder. Weigh 7.5 g of yttrium chloride and 7.5 g of lanthanum oxide as sintering aids, weigh 70 g of PP, 30 g of paraffin wax, 2.5 g of stearic acid, and 0.5 g of diisopropylbenzene peroxide as the binder components, and weigh 25 g of pore former. First, add the binder components into a mixer and heat to melt them, then add the ceramic powder, sintering aids, and pore former. After kneading at 200 ± 5 °C for 5 h, obtain a kneaded material. Put the kneaded material into a granulator to granulate and obtain granular material. Add the granular material into an injection molding machine and inject mold at 180 ± 5 °C, a speed of 60 m / s, and a pressure of 120 MPa to obtain a green body. Put the green body into a sagger, sprinkle the buried firing powder in the sagger until the green body is completely covered, then put the sagger and the green body together into a sintering furnace. First, heat up at a heating rate of 6 °C / min to 800 °C, keep warm for degassing for 2 h, and then heat up at a heating rate of 0.5 °C / min to 1500 °C, keep warm for sintering for 3 h, and then naturally cool to room temperature and take out of the furnace.

[0040] Among them, the pore former is exactly the same as that in the example.

[0041] Example 3:

[0042] A preparation method of a microporous ceramic atomization core:

[0043] Add 200 g of alumina powder, 40 g of aluminum nitride powder, and 10 g of silicon carbide powder into the ball milling tank of a planetary ball mill. The ball-to-material ratio is 3:1. Using ethanol as the ball milling medium, ball mill at a speed of 400 r / min for 8 h and then dry to obtain ceramic powder. Weigh 7.5 g of yttrium chloride and 7.5 g of lanthanum oxide as sintering aids, weigh 70 g of PP, 30 g of paraffin wax, 2.5 g of stearic acid, and 0.5 g of diisopropylbenzene peroxide as the binder components, and weigh 25 g of pore former. First, add the binder components into a mixer and heat to melt them, then add the ceramic powder, sintering aids, and pore former. After kneading at 200 ± 5 °C for 5 h, obtain a kneaded material. Put the kneaded material into a granulator to granulate and obtain granular material. Add the granular material into an injection molding machine and inject mold at 180 ± 5 °C, a speed of 60 m / s, and a pressure of 120 MPa to obtain a green body. Put the green body into a sagger, sprinkle the buried firing powder in the sagger until the green body is completely covered, then put the sagger and the green body together into a sintering furnace. First, heat up at a heating rate of 3 °C / min to 700 °C, keep warm for degassing for 2 h, and then heat up at a heating rate of 0.1 °C / min to 1420 °C, keep warm for sintering for 2 h, and then naturally cool to room temperature and take out of the furnace.

[0044] Among them, the pore former is exactly the same as that in the example.

[0045] Comparative Example 1:

[0046] It is basically the same as Example 1, except that the pore former does not include the silica sol inner shell.

[0047] Comparative Example 2:

[0048] It is basically the same as Example 1, except that the pore former does not include the acrylate polymer shell.

[0049] Comparative Example 3:

[0050] It is basically the same as Example 1, except that the binder component does not include ditert-butylperoxide diisopropylbenzene.

[0051] Comparative Example 4:

[0052] It is basically the same as Example 1, except that the sintering aid is 15 g of yttrium chloride.

[0053] Comparative Example 5:

[0054] It is basically the same as Example 1, except that the sintering aid is 15 g of lanthanum oxide.

[0055] Performance Test:

[0056] Specimens were prepared according to the methods in Examples 1-3 and Comparative Examples 1-5 respectively for performance testing;

[0057] Porosity: The Archimedes drainage method was used, unit: %;

[0058] Compressive strength: According to the test standard of GB / T4740-1999, an electronic universal testing machine was used to test the samples, unit: MPa;

[0059] Thermal conductivity: According to the test standard of GB / T 5990-2006, unit: W / (m·k);

[0060] Oil absorption rate: Measured by the MAYZUM ceramic core oil absorption rate tester, unit: mg / s;

[0061] The performance test results are shown in Table 1 below:

[0062] Table 1:

[0063]

[0064]

[0065] As can be seen from Table 1 above, the microporous ceramic atomization core prepared by the present invention has a high porosity and mechanical properties, high thermal conductivity, and fast oil absorption rate.

[0066] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A preparation method of a microporous ceramic atomization core, characterized in that, specifically as follows: Mix ceramic powder, sintering aid, binder component and pore-forming agent, granulate, and injection mold to obtain a green body, and then heat the green body to remove binder and sinter it; The particle size of the pore-forming agent is 1-50 μm; The pore-forming agent uses mesophase pitch as the core, silica sol as the inner shell, and acrylate polymer as the outer shell; The preparation method of the pore-forming agent is as follows: Mix mesophase pitch and silica sol evenly, heat it in a water bath to 60-80 °C, stir for 2-5 h, then filter and dry. Mix the obtained product with an aqueous solution of water-soluble polymer, stir at high speed for 30-90 min, then add mixed monomers and free radical initiator, heat it in a water bath to 40-80 °C and react for 4-8 h, then filter, and dry the obtained product; The aqueous solution of water-soluble polymer is an aqueous solution of hydroxypropyl methylcellulose and / or hydroxyethyl ethylcellulose; The mixed monomers are composed of MMA, BA, and St; The weight ratio of MMA, BA, and St is 10-20:15-20:3-6.

2. The preparation method of the microporous ceramic atomization core according to claim 1, characterized in that, The ceramic powder includes alumina powder, aluminum nitride powder, and silicon carbide powder; The weight ratio of the alumina powder, aluminum nitride powder, and silicon carbide powder is 10-20:3-5:1-3.

3. The preparation method of the microporous ceramic atomization core according to claim 1, characterized in that, The sintering aid includes yttrium chloride and lanthanum oxide; The weight ratio of yttrium chloride and lanthanum oxide is 1-5:1-5.

4. The preparation method of the microporous ceramic atomization core according to claim 1, characterized in that, The binder component includes PP, paraffin, stearic acid, and bis(tert-butylperoxy)diisopropylbenzene; The weight ratio of PP, paraffin, stearic acid, and bis(tert-butylperoxy)diisopropylbenzene is 50-70:20-40:2-3:0.1-1.

5. The preparation method of the microporous ceramic atomization core according to claim 1, characterized in that, The weight ratio of the ceramic powder, sintering aid, binder component, and pore-forming agent is 1:0.05-0.15:0.3-0.5:0.1-0.

2.

6. The preparation method of the microporous ceramic atomization core according to claim 1, characterized in that, The binder removal temperature is 700-800 °C, and the binder removal time is 1-2 h.

7. The preparation method of the microporous ceramic atomization core according to claim 1, characterized in that, The sintering temperature is 1400-1500 °C, and the sintering time is 1-3 h.

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