Preparation method of porous ceramic material for electronic cigarette

Abstract

The invention discloses a preparation method of a porous ceramic material for an electronic cigarette, and relates to the field of porous ceramic materials. Cotton fibers loaded with nano calcium carbonate are used as a pore-forming agent, after high-temperature sintering, the cotton fibers can be carbonized at high temperature to form pores, calcium carbonate can be further decomposed on the pores to form micron-sized spherical pores, a multi-stage structure of'large-pore oil guiding and small-pore oil locking 'is formed, meanwhile, a carbon skeleton can be left after the cotton fibers are carbonized, and the pore-forming effect is improved. Supporting and reinforcing effects can be achieved in the porous ceramic material, and the risk of breakage is reduced; the porous ceramic for the electronic cigarette is placed in a KH570 silane coupling agent solution, a layer of film is formed on the surfaces of calcium oxide and the ceramic, the wear resistance of the surfaces is improved, erosion of chemical components in tobacco tar can be resisted, the service life of the porous ceramic for the electronic cigarette is prolonged, the lipophilicity of the treated ceramic surface is improved, and the porous ceramic has better tobacco tar adsorption and release performance. According to the prepared porous ceramic material for the electronic cigarette, the strength and the oil guiding performance of the porous ceramic material are improved.

Description

Technical Field

[0001] This invention relates to the field of porous ceramics technology, specifically to a porous ceramic material for electronic cigarettes and its preparation method. Background Technology

[0002] Porous ceramics, with their excellent high-temperature and high-pressure resistance, as well as outstanding resistance to acid, alkali, and organic media corrosion, have demonstrated broad application potential in numerous fields, including but not limited to filters, catalyst supports, energy-saving insulation materials, adsorbent materials, and sound-absorbing materials. Their preparation processes are diverse, encompassing several mature technological routes such as the pore-forming agent method, foaming method, sol-gel method, and solid-state sintering method. These abundant preparation methods lay a solid foundation for the large-scale production of porous ceramics.

[0003] With social progress and increased public health awareness, consumers are demanding higher standards for smoking safety. Given the addictive nature of traditional cigarettes and the difficulty of quitting, e-cigarettes, as a new alternative, have gradually become the mainstream choice in the market. Among the core components of e-cigarettes, the atomizer plays a crucial role as the heating element, and the porous ceramic carrier material used to absorb e-liquid is particularly important. This type of inorganic non-metallic porous ceramic material not only possesses excellent adsorption performance but also features non-toxicity, safety, reliability, non-flammability, and good chemical stability. It is worth noting that the porosity, pore size, and distribution characteristics of the porous ceramic have a decisive impact on the atomization effect and user experience.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing porous ceramic materials for electronic cigarettes, so as to solve the problems existing in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a porous ceramic material for electronic cigarettes, comprising the following preparation steps: (1) The adhesive is heated and dissolved, and then ceramic powder, pore-forming agent, sintering aid and modifier are added, mixed evenly and kneaded to obtain kneaded material. The pore-forming agent is cotton fiber loaded with nano calcium carbonate. (2) The mortar is placed on a casting machine to form a porous ceramic green body; (3) The porous ceramic green body is degreased and sintered to obtain a porous ceramic matrix; (4) Place the porous ceramic matrix in KH570 silane coupling agent solution, stir and react for 30-60 minutes, filter to obtain solid, wash with ethanol 2-3 times, wash with deionized water 2-3 times to obtain porous ceramic material for electronic cigarettes.

[0007] Furthermore, the porous ceramic material for electronic cigarettes comprises the following components in parts by weight: 40-75 parts of ceramic powder, 10-35 parts of pore-forming agent, 5-30 parts of sintering aid, 0.01-3 parts of modifier, and 5-25 parts of binder.

[0008] Furthermore, the ceramic powder includes one or more of diatomaceous earth, cordierite, alumina, zirconium oxide, silicon carbide, silicon nitride, and quartz sand. Furthermore, the sintering aid includes one or more of glass powder, metal oxides, alkali metal oxides, and transition metal oxides; The modifier is one or more of oleic acid, stearic acid, and polyamide wax; The adhesive is one or more of paraffin wax, polyethylene, polypropylene, epoxy resin, phenolic resin, and polystyrene.

[0009] Furthermore, the ceramic material has a particle size of 20-30 μm, the cotton fiber has a length of 100-180 μm and a wire diameter of 5-20 μm, and the nano-calcium carbonate has a size of 50-100 nm.

[0010] Furthermore, in step (1), the adhesive is dissolved at a temperature of 200-250°C, and the mixing is performed by vacuum stirring at a vacuum level of 300-600 Pa for 30-45 minutes at a speed of 600-1200 r / min.

[0011] Furthermore, in step (1), the mixing process involves mixing the ingredients in a mixer at a temperature of 60-65°C for 5-8 hours.

[0012] Furthermore, in step (2), the height of the scraper during casting is 1.5~4.0mm, the speed of the casting machine is 1.0~3.5cm / s, and the thickness of the porous ceramic green body is 400~700μm.

[0013] Furthermore, in step (3), the glue removal is carried out by raising the temperature to 200°C at 0.2~1°C / min, then raising the temperature to 400°C at 0.5~2°C / min, and holding for 1 hour. The degreasing and sintering temperature is 500~1500°C, and the time is 1~3 hours.

[0014] Furthermore, in step (4), the KH570 silane coupling agent solution is prepared by mixing the KH570 silane coupling agent solution with ethanol at a volume ratio of 0.004~0.010:1, and the liquid-solid ratio of the KH570 silane coupling agent solution to the porous ceramic matrix is ​​20~30mL / g.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention first allows cotton fiber pore-forming agent loaded with calcium carbonate to be oriented in a ceramic matrix, and then hot-pressed to form a porous ceramic material for electronic cigarettes, thereby improving the strength and oil conductivity of the porous ceramic material.

[0016] First, calcium carbonate is deposited in situ on cotton fibers as a pore-forming agent. Then, the cotton fibers are oriented in a ceramic matrix using a casting method, followed by sintering to obtain a porous ceramic material for electronic cigarettes. After high-temperature sintering, the cotton fibers carbonize to form pores, and the calcium carbonate further decomposes on the pores to form micron-sized spherical pores, increasing the specific surface area and oil storage capacity. This creates a multi-level structure of "large pores for oil conduction + small pores for oil locking," improving oil conduction efficiency and leak-proof performance. At the same time, the carbonization of the cotton fibers leaves a carbon skeleton, which reduces the sintering shrinkage of the ceramic, maintains the porous structure and performance stability of the material, and has high strength and toughness. It can play a supporting and reinforcing role in the porous ceramic material, improving the overall structural stability of the ceramic and enabling it to better disperse stress when subjected to external forces, reducing the risk of fracture.

[0017] Secondly, the high-temperature decomposition of calcium carbonate leaves pores in the ceramic, exposing calcium oxide. Placing the porous ceramic matrix in a KH570 silane coupling agent solution forms a film on the calcium oxide and ceramic surface, fixing the calcium oxide particles and other ceramic powders. When subjected to external friction or wear, the calcium oxide particles are less likely to fall off the matrix, helping to maintain the integrity of the ceramic matrix, improving its surface wear resistance, resisting the erosion of chemical components in e-liquid, preventing the release of harmful substances, improving the corrosion resistance of the ceramic, and extending the service life of porous ceramics for e-cigarettes. Furthermore, the lipophilicity of the ceramic surface after silane coupling agent treatment is improved, resulting in better e-liquid adsorption and release performance, enhancing the user experience. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The testing methods for various indicators of the porous ceramic material for electronic cigarettes prepared in the following embodiments are as follows: Bending strength: The bending strength of the porous ceramic materials for electronic cigarettes prepared by the same mass of the examples and comparative examples was determined according to GB / T1965-1996 "Test method for bending strength of porous ceramics".

[0020] Oil conduction speed: Using the same mass of porous ceramic materials for electronic cigarettes prepared in the examples and comparative examples, and selecting a mixture of e-liquid with a volume ratio of 1:1 propylene glycol: glycerin, a drop of e-liquid was dropped onto the surface of the porous ceramic material for electronic cigarettes using a straw. The weight of the porous ceramic atomizer core before and after oil absorption (the difference in mass before and after absorption is the amount of e-liquid absorbed by the porous ceramic atomizer core) and the time it takes for the drop of e-liquid to be completely absorbed were recorded. The amount of e-liquid absorbed per unit time is the oil conduction speed.

[0021] Service life: The service life (hours) of the porous ceramic material for electronic cigarettes prepared by the same mass of the example and the comparative example is calculated by continuously heating at full power under the condition of oil absorption rate greater than 50% until the core burns out.

[0022] Example 1 A method for preparing a porous ceramic material for electronic cigarettes includes the following preparation steps: (1) Cotton fibers with a length of 120 μm and a diameter of 10 μm were placed in a 1.5 g / L calcium hydroxide solution and soaked for 30 min. Then, they were soaked and rolled twice. The rolling pressure was 0.3 MPa and the liquid content of the cotton fibers was 80%. The soaked cotton fibers were placed in a container filled with carbon dioxide and carbon dioxide was continuously introduced at a flow rate of 300 mL / min. The reaction was carried out for 30 min. The fibers were then dried in a 60℃ constant temperature drying oven. After two deion washings, the fibers were dried in a 60℃ constant temperature drying oven to obtain cotton fibers loaded with nano-calcium carbonate. (2) The following components are taken according to the mass parts: 30 parts of diatomaceous earth, 30 parts of quartz sand, 15 parts of cotton fiber loaded with nano calcium carbonate, 15 parts of glass powder, 0.5 parts of oleic acid and 15 parts of paraffin wax. The particle size of diatomaceous earth and quartz sand is 20 μm. (3) According to the formula, the paraffin wax will be heated and dissolved at 200°C, and then ceramic powder, cotton fiber loaded with nano calcium carbonate, glass powder and oleic acid will be added. The mixture will be stirred for 30 minutes at a vacuum of 300 Pa and 600 r / min, and then placed in a mixer at 60°C for 5 hours to obtain the mixed material. (4) The intensively mixed material is placed on a casting machine to form a porous ceramic green body with a thickness of 400μm. The height of the scraper during casting is 2.0mm and the speed of the casting machine is 1.5cm / s. (5) The porous ceramic green body is heated to 200°C at 0.5°C / min, then heated to 400°C at 1°C / min, and held for 1 hour for debinding treatment. Then it is sintered at 1000°C for 2 hours to obtain a porous ceramic matrix. (6) A silane coupling agent solution was prepared by mixing KH570 silane coupling agent solution with ethanol at a volume ratio of 0.004:1. The porous ceramic matrix was placed in the KH570 silane coupling agent solution with a liquid-to-solid ratio of 20 mL / g. After stirring for 30 minutes, the solid was filtered and washed 3 times with ethanol and 3 times with deionized water to obtain the porous ceramic material for electronic cigarettes.

[0023] Example 2 A method for preparing a porous ceramic material for electronic cigarettes includes the following preparation steps: (1) Cotton fibers with a length of 150 μm and a diameter of 15 μm were placed in a 1.5 g / L calcium hydroxide solution and soaked for 30 min. Then, they were soaked and rolled twice. The rolling pressure was 0.3 MPa and the liquid content of the cotton fibers was 80%. The soaked cotton fibers were placed in a container filled with carbon dioxide and carbon dioxide was continuously introduced at a flow rate of 300 mL / min. The reaction was carried out for 35 min and then dried in a 60℃ constant temperature drying oven. After deion washing three times, the cotton fibers loaded with nano-calcium carbonate were dried again in a 60℃ constant temperature drying oven. (2) The following components are taken according to the mass parts: 30 parts of diatomaceous earth, 35 parts of silicon carbide, 20 parts of cotton fiber loaded with nano calcium carbonate, 20 parts of glass powder, 1 part of oleic acid and 18 parts of paraffin. The particle size of diatomaceous earth and silicon carbide is 25 μm. (3) According to the formula, the paraffin wax will be heated and dissolved at 230°C, and then ceramic powder, cotton fiber loaded with nano calcium carbonate, glass powder and oleic acid will be added. The mixture will be stirred for 40 minutes at a vacuum of 500 Pa and 800 r / min, and then placed in a mixer at 65°C for 6 hours to obtain the mixed material. (4) The intensively mixed material is placed on a casting machine to form a porous ceramic green body with a thickness of 600μm. The height of the scraper during casting is 2.5mm and the speed of the casting machine is 2.0cm / s. (5) The porous ceramic green body is heated to 200°C at 0.5°C / min, then heated to 400°C at 1.5°C / min, and held for 1 hour for debinding treatment. Then it is sintered at 1200°C for 2 hours to obtain a porous ceramic matrix. (6) A silane coupling agent solution was prepared by mixing KH570 silane coupling agent solution with ethanol at a volume ratio of 0.007:1. The porous ceramic matrix was placed in the KH570 silane coupling agent solution with a liquid-to-solid ratio of 25 mL / g. After stirring for 45 minutes, the solid was filtered and washed 3 times with ethanol and 3 times with deionized water to obtain the porous ceramic material for electronic cigarettes.

[0024] Example 3 A method for preparing a porous ceramic material for electronic cigarettes includes the following preparation steps: (1) Cotton fibers with a length of 180 μm and a diameter of 20 μm were placed in a 1.5 g / L calcium hydroxide solution and soaked for 30 min. Then, they were soaked and rolled twice. The rolling pressure was 0.3 MPa and the liquid content of the cotton fibers was 80%. The soaked cotton fibers were placed in a container filled with carbon dioxide and carbon dioxide was continuously introduced at a flow rate of 300 mL / min. The reaction was carried out for 40 min. The fibers were then dried in a 60℃ constant temperature drying oven, deionized and washed 3 times, and then dried in a 60℃ constant temperature drying oven to obtain cotton fibers loaded with nano-calcium carbonate. (2) The following components are taken according to the mass parts: 30 parts of diatomaceous earth, 35 parts of cordierite, 25 parts of cotton fiber loaded with nano calcium carbonate, 25 parts of glass powder, 1.5 parts of oleic acid and 20 parts of paraffin. The particle size of diatomaceous earth and cordierite is 20~30μm. (3) According to the formula, the paraffin wax will be heated and dissolved at 250°C, and then ceramic powder, cotton fiber loaded with nano calcium carbonate, glass powder and oleic acid will be added. The mixture will be stirred at a vacuum of 600 Pa and 1200 r / min for 45 min, and then placed in a mixer at 65°C for 8 hours to obtain the mixed material. (4) The intensively mixed material is placed on a casting machine to form a porous ceramic green body with a thickness of 700μm. The height of the scraper during casting is 4.0mm and the speed of the casting machine is 3.5cm / s. (5) The porous ceramic green body is heated to 200°C at 1°C / min, then heated to 400°C at 2°C / min, and held for 1 hour for debinding treatment. Then it is sintered at 1500°C for 3 hours to obtain a porous ceramic matrix. (6) A silane coupling agent solution was prepared by mixing KH570 silane coupling agent solution with ethanol at a volume ratio of 0.010:1. The porous ceramic matrix was placed in the KH570 silane coupling agent solution with a liquid-to-solid ratio of 30 mL / g. After stirring for 60 minutes, the solid was filtered and washed 3 times with ethanol and 3 times with deionized water to obtain the porous ceramic material for electronic cigarettes.

[0025] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that step (1) is omitted, and step (2) is changed to: taking the following components by mass: 30 parts of diatomaceous earth, 35 parts of silicon carbide, 20 parts of cotton fiber, 20 parts of glass powder, 1 part of oleic acid and 18 parts of paraffin wax, with the particle size of diatomaceous earth and silicon carbide being 25 μm; step (3) is changed to: according to the formula, heating and dissolving paraffin wax at 230°C, then adding ceramic powder, cotton fiber, glass powder and oleic acid, stirring at a vacuum of 500 Pa and 800 r / min for 40 min, and mixing in a mixer at 65°C for 6 hours to obtain the mixed material; the remaining steps are the same as in Example 2.

[0026] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that step (1) is omitted, and step (2) is changed to: taking the following components by mass: 30 parts of diatomaceous earth, 35 parts of silicon carbide, 20 parts of calcium carbonate, 20 parts of glass powder, 1 part of oleic acid and 18 parts of paraffin wax, with the particle size of diatomaceous earth and silicon carbide being 25 μm; step (3) is changed to: according to the formula, heating and dissolving paraffin wax at 230°C, then adding ceramic powder, calcium carbonate, glass powder and oleic acid, stirring at a vacuum of 500 Pa and 800 r / min for 40 min, and mixing in a mixer at 65°C for 6 hours to obtain the mixed material; the remaining steps are the same as in Example 2.

[0027] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that step (4) is omitted. Step (4) is changed to: placing the mortar into a hot die casting machine and hot die casting at 80°C and 0.5MPa to obtain a porous ceramic green body; the remaining steps are the same as in Example 2.

[0028] Comparative Example 4 The difference between Comparative Example 4 and Example 2 is that step (6) is omitted, and step (5) is changed to: heating the porous ceramic green body to 200°C at 0.5°C / min, then heating it to 400°C at 1.5°C / min, holding it at 1h for debinding, and then sintering it at 1200°C for 2h to obtain a porous ceramic matrix. The porous ceramic matrix is ​​washed with ethanol 3 times and deionized water 3 times to obtain the porous ceramic material for electronic cigarettes; the remaining steps are the same as in Example 2.

[0029] Example of effect Table 1 below shows the performance analysis results of the porous ceramic materials for electronic cigarettes using Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention.

[0030] Table 1 A comparison of the experimental data from Example 2 with Comparative Examples 1 and 2 reveals that after high-temperature sintering, the cotton fibers of this invention undergo high-temperature carbonization to form pores. Calcium carbonate further decomposes on these pores to form micron-sized spherical pores, increasing the specific surface area and oil storage capacity. This creates a multi-level structure of "large-pore oil conduction + small-pore oil locking," improving oil conduction efficiency and leak-proof performance. Simultaneously, the carbon skeleton left after cotton fiber carbonization reduces sintering shrinkage, maintains the porous structure and performance stability of the material, and possesses high strength and toughness, providing support and reinforcement in porous ceramic materials. This enhances the overall structural stability of the ceramic, allowing it to better disperse stress and reduce the risk of fracture when subjected to external forces. A comparison of the experimental data from Example 2 with Comparative Example 3 shows that this invention, through a casting method, directionally arranges cotton fibers in the ceramic matrix, generating pores... The orderly arrangement of pores has a positive effect on the flexural strength, conductivity, and service life of porous ceramics. A comparison of experimental data from Example 2 and Comparative Example 4 reveals that the high-temperature decomposition of calcium carbonate leaves pores in the ceramic, exposing calcium oxide. Placing the porous ceramic in a KH570 silane coupling agent solution forms a film on the calcium oxide and ceramic surface, fixing the calcium oxide particles and other ceramic powders. Under external friction or wear, the calcium oxide particles are less likely to detach from the matrix, helping to maintain the integrity of the ceramic matrix, improving its surface wear resistance, resisting the erosion of chemical components in e-liquid, preventing the release of harmful substances, improving the corrosion resistance of the ceramic, and extending the service life of porous ceramics for e-cigarettes. Furthermore, the lipophilicity of the ceramic surface treated with the silane coupling agent is improved, resulting in better e-liquid adsorption and release performance, enhancing the user experience.

[0031] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing a porous ceramic material for electronic cigarettes, comprising the following preparation steps: (1) Cotton fibers with a length of 150 μm and a diameter of 15 μm were placed in a 1.5 g / L calcium hydroxide solution and soaked for 30 min. Then, they were soaked and rolled twice. The rolling pressure was 0.3 MPa and the liquid content of the cotton fibers was 80%. The soaked cotton fibers were placed in a container filled with carbon dioxide and carbon dioxide was continuously introduced at a flow rate of 300 mL / min. The reaction was carried out for 35 min and then dried in a 60℃ constant temperature drying oven. After deion washing three times, the cotton fibers loaded with nano-calcium carbonate were dried again in a 60℃ constant temperature drying oven. (2) The following components are taken according to the mass parts: 30 parts of diatomaceous earth, 35 parts of silicon carbide, 20 parts of cotton fiber loaded with nano calcium carbonate, 20 parts of glass powder, 1 part of oleic acid and 18 parts of paraffin. The particle size of diatomaceous earth and silicon carbide is 25 μm. (3) According to the formula, the paraffin wax will be heated and dissolved at 230°C, and then ceramic powder, cotton fiber loaded with nano calcium carbonate, glass powder and oleic acid will be added. The mixture will be stirred for 40 minutes at a vacuum of 500 Pa and 800 r / min, and then placed in a mixer at 65°C for 6 hours to obtain the mixed material. (4) The intensively mixed material is placed on a casting machine to form a porous ceramic green body with a thickness of 600μm. The height of the scraper during casting is 2.5mm and the speed of the casting machine is 2.0cm / s. (5) The porous ceramic green body is heated to 200°C at 0.5°C / min, then heated to 400°C at 1.5°C / min, and held for 1 hour for debinding treatment. Then it is sintered at 1200°C for 2 hours to obtain a porous ceramic matrix. (6) A silane coupling agent solution was prepared by mixing KH570 silane coupling agent solution with ethanol at a volume ratio of 0.007:

1. The porous ceramic matrix was placed in the KH570 silane coupling agent solution with a liquid-to-solid ratio of 25 mL / g. After stirring for 45 minutes, the solid was filtered and washed 3 times with ethanol and 3 times with deionized water to obtain the porous ceramic material for electronic cigarettes.

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