A zirconia-based tobacco heating ceramic tube and its preparation method

Abstract

The present invention relates to the field of ceramic materials, and specifically to a zirconia-based tobacco heating ceramic tube and a preparation method thereof. Calculated by weight parts, the raw materials used in the preparation include the following components: 80-100 parts of zirconia, 0.1-1 part of nitrogen-containing additive, 5-10 parts of aluminum salt, 20-25 parts of organic carbon, 1-3 parts of sintering aid, and an appropriate amount of pH regulator. The zirconia-based tobacco heating ceramic tube prepared by the present invention has good mechanical properties and a relatively high thermal conductivity, and by increasing the heating rate of the ceramic tube, the waiting time for heating tobacco is shortened, thereby enhancing the usage experience effect.

Description

Technical Field

[0001] The invention relates to the field of ceramic materials, in particular to a zirconium oxide-based tobacco heating ceramic tube and a preparation method thereof. Background Art

[0002] Traditional tobacco products refer to tobacco products that produce aerosols through combustion, with a heating temperature of around 900°C. During the combustion and decomposition process, they release substances that are harmful to the human body, and have adverse effects on the public environment and the health of others.

[0003] Heat-not-burn cigarettes are a type of cigarette that produces tobacco flavor gas by heating tobacco through a heat source without igniting the tobacco. Compared with traditional tobacco products, heat-not-burn low-temperature cigarettes only produce nicotine when heated to adapt to and meet the physiological and psychological needs of smoking consumers, avoiding the production of large amounts of harmful compounds such as tar, carbon monoxide, and nitrosamines produced by combustion-type cigarettes, reducing the harm of smoking to consumers' health and the impact on the public environment.

[0004] The heating element base materials currently used in heat-not-burn cigarettes can generally be divided into metal bases and non-metal bases according to their properties. Zirconia ceramics are widely used in the production of heating element base materials due to their good strength, hardness, wear resistance and high temperature resistance. However, their low thermal conductivity leads to poor timely responsiveness when heating tobacco and long waiting time, resulting in a decline in consumer experience. Summary of the invention

[0005] Purpose of the invention: In view of the above technical problems, the present invention proposes a zirconium oxide-based tobacco heating ceramic tube and a preparation method thereof.

[0006] The technical solutions adopted are as follows:

[0007] A zirconium oxide-based tobacco heating ceramic tube, the raw materials used for preparation include the following components in parts by weight:

[0008] 80-100 parts of zirconium oxide, 0.1-1 parts of nitrogen-containing additives, 5-10 parts of aluminum salts, 20-25 parts of organic carbon, 1-3 parts of sintering aids, and an appropriate amount of pH regulator.

[0009] Furthermore, the nitrogen-containing additive is any one or more combinations of melamine, thiourea, urea and piperazine.

[0010] Furthermore, the aluminum salt is any one or more combinations of ethyl aluminum, butyl aluminum, aluminum acetate, aluminum isopropoxide, aluminum formate, aluminum oxalate, and aluminum propionate.

[0011] Furthermore, the organic carbon is glucose and / or sucrose.

[0012] Further, the pH regulator is any one or a combination of hydrochloric acid, nitric acid, and sulfuric acid.

[0013] Further, the sintering aid is a metal fluoride.

[0014] Further, the metal fluoride includes calcium oxide and yttrium oxide.

[0015] Further, the mass ratio of calcium oxide to yttrium oxide is 1 - 5:1 - 5.

[0016] The present invention also provides a method for preparing a zirconia-based tobacco heating ceramic tube:

[0017] Dissolve the aluminum salt in an organic solvent, then add zirconia and mix well. Heat to evaporate the organic solvent so that the aluminum salt uniformly coats the surface of the zirconia. Then, using water as a ball milling aid, mix and ball mill the nitrogen-containing additive, organic carbon, zirconia coated with aluminum salt, and the sintering aid for 1 - 20 h. Drop a pH regulator into the obtained mixed slurry until a sol is formed. Dry the sol to obtain a dry gel precursor. Grind the dry gel precursor, granulate and mold it, and under a nitrogen atmosphere, first heat to 1450 - 1600 °C for primary sintering for 1 - 4 h, then cool to 600 - 800 °C for secondary sintering for 1 - 4 h, and finally restore to room temperature.

[0018] Further, the secondary sintering is carried out in an oxygen or air atmosphere.

[0019] Advantages of the present invention:

[0020] The present invention provides a zirconia-based tobacco heating ceramic tube. By using the sol-gel process combined with nitrogen sintering, aluminum nitride nanowires with high thermal conductivity are in-situ generated on the surface of zirconia, and an interconnected thermal conduction network is formed inside the ceramic tube. When heated, heat can be quickly conducted through this thermal conduction network, improving the heating rate of the ceramic tube, thereby shortening the waiting time for heating tobacco and enhancing the usage experience. Moreover, the aluminum nitride nanowires can increase the crack propagation path, crack deflection, and bridging, improving the mechanical strength of the ceramic tube. Compared with direct addition, the in-situ generated aluminum nitride nanowires have a lower degree of agglomeration and a higher degree of dispersion, resulting in better thermal conduction and toughening effects;

[0021] The nitrogen-containing additive can increase the nitridation reaction rate, promote the nitridation reaction, and enhance the growth rate of aluminum nitride nanowires. The sintering aid can, on the one hand, react with aluminum oxide to prevent the generated aluminum oxide from hindering the nitridation reaction during sintering, and on the other hand, itself and the reaction products (calcium oxide and yttrium oxide) can promote sintering, improve the ceramic density, and thus improve the thermal conductivity and mechanical properties of the ceramic tube. Description of the Drawings

[0022] Figure 1 It is an image of the fracture of the ceramic tube prepared in Example 1, and the internal aluminum nitride nanowires can be observed. Detailed implementation manners

[0023] For those not specified with specific conditions in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained by commercial purchase. Technologies not mentioned in the present invention refer to the prior art. Unless otherwise specified, the following examples and comparative examples are parallel tests and adopt the same processing steps and parameters.

[0024] Example 1:

[0025] A zirconia-based tobacco heating ceramic tube, calculated by weight, the raw materials used for preparation include the following components:

[0026] 90 parts of zirconia, 0.5 part of thiourea, 8 parts of aluminum isopropoxide, 22 parts of sucrose, 1 part of calcium oxide, 1 part of yttrium oxide, and an appropriate amount of 1M nitric acid solution.

[0027] The preparation method of the above zirconia-based tobacco heating ceramic tube:

[0028] Add aluminum isopropoxide to ethanol with a mass 10 times that of aluminum isopropoxide. After fully stirring to dissolve it, add zirconia and stir evenly. Heat to evaporate ethanol so that aluminum isopropoxide is uniformly coated on the surface of zirconia. Using water as the ball milling aid, add thiourea, sucrose, zirconia coated with aluminum salt, calcium oxide, and yttrium oxide to the ball milling tank, and mix and ball mill on a planetary ball mill for 5 h. Then, add 1M nitric acid solution dropwise to the obtained mixed slurry until a sol is formed. At this time, the pH of the system is 4. Dry the sol in an oven at 80 °C for 48 h to obtain a dry gel precursor. After fully grinding the dry gel precursor, granulate it with an 8 wt% polyvinyl alcohol solution. The obtained granulated material is pressed at 100 MPa for 10 min to form a shape, and in a nitrogen atmosphere, first heat it to 1500 °C at a rate of 10 °C / min for the first sintering for 4 h, then cool it to 700 °C at a rate of 5 °C / min, perform the second sintering in an air atmosphere for 2 h, and finally restore to room temperature.

[0029] Example 2:

[0030] A zirconia-based tobacco heating ceramic tube, calculated by weight, the raw materials used for preparation include the following components:

[0031] 90 parts of zirconia, 0.4 part of thiourea, 8 parts of aluminum isopropoxide, 22 parts of sucrose, 1 part of calcium oxide, 1 part of yttrium oxide, and an appropriate amount of 1M nitric acid solution.

[0032] The preparation method of the above zirconia-based tobacco heating ceramic tube:

[0033] Add aluminum isopropoxide to ethanol with a mass 10 times that of aluminum isopropoxide. After fully stirring to dissolve it, add zirconia and stir well to mix evenly. Heat to distill off ethanol so that aluminum isopropoxide uniformly coats the surface of zirconia. Using water as a ball milling aid, add thiourea, sucrose, zirconia coated with aluminum salt on the surface, calcium oxide, and yttrium oxide to a ball milling tank, and mix and ball mill on a planetary ball mill for 5 h. Then, add 1 M nitric acid solution dropwise to the obtained mixed slurry until a sol is formed. At this time, the pH of the system is 4. Dry the sol in an oven at 80 °C for 48 h to obtain a dry gel precursor. After fully grinding the dry gel precursor, granulate it with an 8 wt% polyvinyl alcohol solution. Press the obtained granulated material at 100 MPa for 10 min to form a shape, and in a nitrogen atmosphere, first heat it to 1500 °C at a rate of 10 °C / min for the first sintering for 4 h, then cool it to 700 °C at a rate of 5 °C / min, and conduct the second sintering for 2 h in an air atmosphere. Finally, restore to room temperature.

[0034] Example 3:

[0035] A zirconia-based tobacco heating ceramic tube, calculated by weight, the raw materials used for preparation include the following components:

[0036] 90 parts of zirconia, 0.3 parts of thiourea, 8 parts of aluminum isopropoxide, 22 parts of sucrose, 1 part of calcium oxide, 1 part of yttrium oxide, and an appropriate amount of 1 M nitric acid solution.

[0037] The preparation method of the above zirconia-based tobacco heating ceramic tube:

[0038] Add aluminum isopropoxide to ethanol with a mass 10 times that of aluminum isopropoxide. After fully stirring to dissolve it, add zirconia and stir well to mix evenly. Heat to distill off ethanol so that aluminum isopropoxide uniformly coats the surface of zirconia. Using water as a ball milling aid, add thiourea, sucrose, zirconia coated with aluminum salt on the surface, calcium oxide, and yttrium oxide to a ball milling tank, and mix and ball mill on a planetary ball mill for 5 h. Then, add 1 M nitric acid solution dropwise to the obtained mixed slurry until a sol is formed. At this time, the pH of the system is 4. Dry the sol in an oven at 80 °C for 48 h to obtain a dry gel precursor. After fully grinding the dry gel precursor, granulate it with an 8 wt% polyvinyl alcohol solution. Press the obtained granulated material at 100 MPa for 10 min to form a shape, and in a nitrogen atmosphere, first heat it to 1500 °C at a rate of 10 °C / min for the first sintering for 4 h, then cool it to 700 °C at a rate of 5 °C / min, and conduct the second sintering for 2 h in an air atmosphere. Finally, restore to room temperature.

[0039] Example 4:

[0040] A zirconia-based tobacco heating ceramic tube, calculated by weight, the raw materials used for preparation include the following components:

[0041] 90 parts of zirconia, 0.2 parts of thiourea, 8 parts of aluminum isopropoxide, 22 parts of sucrose, 1 part of calcium oxide, 1 part of yttrium oxide, and an appropriate amount of 1M nitric acid solution.

[0042] The preparation method of the above zirconia-based tobacco heating ceramic tube:

[0043] Add aluminum isopropoxide to ethanol with a mass 10 times that of aluminum isopropoxide. After fully stirring to dissolve it, add zirconia and stir evenly. Heat to evaporate ethanol so that aluminum isopropoxide is uniformly coated on the surface of zirconia. Using water as the ball milling aid, add thiourea, sucrose, zirconia coated with aluminum salt on the surface, calcium oxide and yttrium oxide into the ball milling tank, mix and ball mill on a planetary ball mill for 5 h. Then, add 1M nitric acid solution dropwise to the obtained mixed slurry until a sol is formed. At this time, the pH of the system is 4. Dry the sol in an oven at 80 °C for 48 h to obtain a dry gel precursor. Grind the dry gel precursor thoroughly and granulate it with an 8wt% polyvinyl alcohol solution. The obtained pellets are molded by pressing at 100 MPa for 10 min, and in a nitrogen atmosphere, first heat up to 1500 °C at a rate of 10 °C / min for the first sintering for 4 h, then cool down to 700 °C at a rate of 5 °C / min, and conduct the second sintering for 2 h in an air atmosphere. Finally, restore to room temperature.

[0044] Example 5:

[0045] A zirconia-based tobacco heating ceramic tube, in terms of parts by weight, the raw materials used for preparation include the following components:

[0046] 90 parts of zirconia, 0.1 parts of thiourea, 8 parts of aluminum isopropoxide, 22 parts of sucrose, 1 part of calcium oxide, 1 part of yttrium oxide, and an appropriate amount of 1M nitric acid solution.

[0047] The preparation method of the above zirconia-based tobacco heating ceramic tube:

[0048] Add aluminum isopropoxide to ethanol with a mass 10 times that of aluminum isopropoxide. After fully stirring to dissolve it, add zirconia and stir evenly. Heat to evaporate ethanol so that aluminum isopropoxide is uniformly coated on the surface of zirconia. Using water as the ball milling aid, add thiourea, sucrose, zirconia coated with aluminum salt on the surface, calcium oxide and yttrium oxide into the ball milling tank, mix and ball mill on a planetary ball mill for 5 h. Then, add 1M nitric acid solution dropwise to the obtained mixed slurry until a sol is formed. At this time, the pH of the system is 4. Dry the sol in an oven at 80 °C for 48 h to obtain a dry gel precursor. Grind the dry gel precursor thoroughly and granulate it with an 8wt% polyvinyl alcohol solution. The obtained pellets are molded by pressing at 100 MPa for 10 min, and in a nitrogen atmosphere, first heat up to 1500 °C at a rate of 10 °C / min for the first sintering for 4 h, then cool down to 700 °C at a rate of 5 °C / min, and conduct the second sintering for 2 h in an air atmosphere. Finally, restore to room temperature.

[0049] Comparative Example 1:

[0050] It is basically the same as Example 1, except that thiourea is not added.

[0051] Comparative Example 2:

[0052] It is basically the same as Example 1, except that calcium oxide and yttrium oxide are not added.

[0053] Comparative Example 3:

[0054] It is basically the same as Example 1, except that calcium oxide is not added.

[0055] Comparative Example 4:

[0056] It is basically the same as Example 1, except that yttrium oxide is not added.

[0057] Performance detection:

[0058] Specimens were prepared according to the methods in Examples 1-5 and Comparative Examples 1-4 of the present invention and subjected to performance tests.

[0059] The three-point bending method was used to test the flexural strength of the specimens. The test specimen size was 3 mm × 4 mm × 36 mm, the loading rate was selected as 0.5 mm / min, and the span was selected as 30 mm;

[0060] The thermal conductivity of the specimens at room temperature was tested using the TTO component of the PPMS Model 6000 physical property detection system;

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

[0062] Table 1:

[0063]

[0064] As can be seen from Table 1 above, the zirconia-based tobacco heating ceramic tube prepared by the present invention has good mechanical properties and a relatively high thermal conductivity;

[0065] By comparing Example 1 with Comparative Example 1, it can be seen that the addition of thiourea plays a positive role in improving both the mechanical properties and thermal conductivity of the specimens. Thiourea can increase the nitridation reaction rate, promote the nitridation reaction, and increase the growth rate of aluminum nitride nanowires, and the aluminum nitride nanowires have a very obvious improvement on the mechanical properties and thermal conductivity of the specimens;

[0066] It can be seen from the comparison between Example 1 and Comparative Examples 2-4 that the addition of calcium oxide and yttrium oxide plays a positive role in improving the mechanical properties and thermal conductivity of the specimens. On the one hand, calcium oxide and yttrium oxide can react with alumina to prevent the generated alumina from hindering the nitridation reaction during sintering. On the other hand, they themselves and the reaction products (calcium oxide and yttrium oxide) can promote sintering, improve the ceramic density, and thus improve the thermal conductivity and mechanical properties of the ceramic tube.

[0067] 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 described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A zirconium oxide-based tobacco heating ceramic tube, characterized in that: The raw materials used for the preparation include the following components in parts by weight: 90 parts of zirconium oxide, 0.4 parts of thiourea, 8 parts of aluminum isopropoxide, 22 parts of sucrose, 1 part of calcium oxide, 1 part of yttrium oxide, and an appropriate amount of 1M nitric acid solution; The preparation method of the above-mentioned zirconium oxide-based tobacco heating ceramic tube: Aluminum isopropoxide is added to 10 times the mass of ethanol, and after being fully stirred to dissolve, zirconium oxide is added and stirred to mix, and the ethanol is evaporated by heating to make the aluminum isopropoxide uniformly coated on the surface of the zirconium oxide. Thiourea, sucrose, zirconium oxide coated with aluminum salt on the surface, calcium oxide and yttrium oxide are added to a ball mill with water as a ball milling aid, and mixed and ball-milled on a planetary ball mill for 5 hours. Then, 1M nitric acid solution is added dropwise to the obtained mixed slurry to form a sol. At this time, the pH of the system is 4. The sol is dried in an oven at 80°C for 48 hours to obtain a dry gel precursor. After the dry gel precursor is fully ground, it is granulated with an 8wt% polyvinyl alcohol solution. The obtained pellets are pressed at 100MPa for 10 minutes to form, and in a nitrogen atmosphere, the temperature is first increased to 1500°C at a rate of 10°C / min and sintered for 4 hours, then cooled to 700°C at a rate of 5°C / min, sintered for 2 hours in an air atmosphere, and finally restored to room temperature.

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