Heat-conducting porous ceramic atomizing core, preparation method and application thereof

Abstract

The application provides a heat-conducting porous ceramic atomizing core and a preparation method and application thereof, and particularly relates to the technical field of ceramic materials. The heat-conducting porous ceramic atomizing core has a sandwich structure and comprises a first heat-conducting layer, an intermediate layer and a second heat-conducting layer which are arranged in layers; the surface of the first heat-conducting layer or the second heat-conducting layer away from the intermediate layer is provided with an electrode; the first heat-conducting layer, the intermediate layer and the second heat-conducting layer are formed by laminating slurry A, slurry B and slurry A and then sintering the laminated layers. The first heat-conducting layer and the second heat-conducting layer are arranged on the two sides of the intermediate layer in the sandwich structure, so that the bending deformation does not occur even if the ceramic shrinks due to the different materials of the layers. Under the same atomizing power, the atomizing surface temperature of the heat-conducting porous ceramic atomizing core is increased by 15 DEG C-30 DEG C, the atomizing amount is increased by 30%-60%, the taste is full and continuous in the front, middle and rear stages, and the ceramic body does not bend and deform.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic materials, in particular to a heat-conducting porous ceramic atomizing core and a preparation method and application thereof. BACKGROUND

[0002] The ceramic atomizing core is a core component of an electronic cigarette. In terms of structure, it can be divided into two parts: a heating electrode and a porous ceramic base. First, the heating electrode is mainly composed of a metal material and has a certain resistance value. When the power supply is turned on, the tobacco oil near the heating electrode can be atomized. Second, the functions of the ceramic base in the electronic cigarette mainly include: refining tobacco oil droplets, storing tobacco oil, conducting tobacco oil, and surface atomization.

[0003] At present, the maximum temperature of the atomizing surface of the porous ceramic atomizing core is mostly concentrated in the range of 200-215 DEG C, and the temperature distribution is uneven, and the atomization amount is small. Most of the existing high-thermal-conductivity materials are metal materials. Coating a thin layer of metal film on the surface of the ceramic atomizing core and then metallizing will certainly improve the thermal conductivity to some extent, but this will make the preparation process more complex and the preparation cost higher.

[0004] Therefore, the present application is proposed. SUMMARY

[0005] One of the purposes of the present application is to provide a heat-conducting porous ceramic atomizing core to alleviate the technical problem of low atomizing surface temperature of the porous ceramic atomizing core in the prior art, which causes poor atomization effect.

[0006] The second purpose of the present application is to provide a preparation method of a heat-conducting porous ceramic atomizing core.

[0007] The third purpose of the present application is to provide an application of a heat-conducting porous ceramic atomizing core in an electronic cigarette.

[0008] In order to achieve the above-mentioned purposes of the present application, the following technical solutions are adopted:

[0009] The first aspect of the present application provides a heat-conducting porous ceramic atomizing core having a sandwich structure, comprising a first heat-conducting layer, an intermediate layer and a second heat-conducting layer which are stacked.

[0010] The surface of the first heat-conducting layer or the second heat-conducting layer away from the intermediate layer is provided with an electrode.

[0011] The first heat-conducting layer, the intermediate layer and the second heat-conducting layer are formed by casting and then stacking and sintering the slurry A, the slurry B and the slurry A.

[0012] Further, the slurry A comprises, in terms of mass fractions, 35-45 parts of the thermally conductive ceramic aggregate, 10-20 parts of the first pore former, 20-35 parts of the first organic solvent, 15-25 parts of the first binder, and 0.5-1.5 parts of the first dispersant.

[0013] Preferably, the slurry B comprises, in terms of mass fractions, 35-45 parts of the large-particle ceramic aggregate, 10-20 parts of the second pore former, 20-30 parts of the second organic solvent, 15-25 parts of the second binder, and 0.5-1.5 parts of the second dispersant.

[0014] Further, the thermally conductive ceramic aggregate has a particle size of 20-80 μm.

[0015] Preferably, the thermally conductive ceramic aggregate comprises a first ceramic aggregate, a second ceramic aggregate, and a first sintering aid.

[0016] The first ceramic aggregate comprises at least one of beryllium oxide, aluminum nitride, silicon carbide, and polycrystalline diamond.

[0017] The second ceramic aggregate comprises silicon dioxide.

[0018] The first sintering aid comprises glass.

[0019] Further, the large-particle ceramic aggregate has a particle size of 30-100 μm.

[0020] Preferably, the large-particle ceramic aggregate comprises a third ceramic aggregate and a second sintering aid.

[0021] The third ceramic aggregate comprises at least one of corundum, diatomite, and quartz.

[0022] The second sintering aid comprises glass.

[0023] Further, the first pore former or the second pore former is each independently selected from at least one of plastic beads, fibers, and starch.

[0024] Preferably, the first pore former has an average particle size of 50-100 μm.

[0025] Preferably, the second pore former has an average particle size of 80-150 μm.

[0026] Further, the first organic solvent or the second organic solvent is each independently selected from at least one of toluene, ethanol, and xylene.

[0027] Preferably, the first binder or the second binder comprises a PVB dispersion.

[0028] Preferably, the solid content of the PVB dispersion is 12%-20%.

[0029] Preferably, the first dispersant or the second dispersant is independently selected from castor oil and / or triolein.

[0030] The second aspect of the present application provides a preparation method of the heat-conducting porous ceramic atomizing core, comprising the following steps:

[0031] a. respectively casting the slurry A and the slurry B to obtain green film strips A and B;

[0032] b. stacking and arranging the green film strips A to obtain a first heat-conducting layer and a second heat-conducting layer respectively, and stacking and arranging the green film strips B to obtain an intermediate layer, and stacking and arranging the first heat-conducting layer, the intermediate layer and the second heat-conducting layer in sequence, and then flattening and compacting to obtain a green body of the heat-conducting porous ceramic atomizing core;

[0033] c. debinding and first sintering the green body of the heat-conducting porous ceramic atomizing core to obtain a substrate of the heat-conducting porous ceramic atomizing core;

[0034] d. printing electrodes on the substrate of the heat-conducting porous ceramic atomizing core with the first heat-conducting layer or the second heat-conducting layer away from the surface of the intermediate layer, and then second sintering to obtain the heat-conducting porous ceramic atomizing core.

[0035] Further, in step a, the thickness of the green film strips A and B is independently 200-400 μm.

[0036] Preferably, in step b, the thickness of the first heat-conducting layer and the second heat-conducting layer is independently 0.4-1 mm, and the thickness of the intermediate layer is 2-3 mm.

[0037] Preferably, in step b, the flattening pressure is 120-140 kg.

[0038] Further, in step c, the debinding temperature is 300-550 ℃, and the debinding time is 5-10 h.

[0039] Preferably, in step c, the first sintering temperature is 1000-1400 ℃, the first sintering time is 10-15 h, and the holding time is 2-3 h.

[0040] Preferably, in step c, the first sintering is carried out in a vacuum state, and the vacuum degree of the first sintering is ≤10 Pa.

[0041] Preferably, in step d, the second sintering is carried out in a vacuum state, and the vacuum degree of the second sintering is ≤10 Pa, and the second sintering temperature is 900-1050 ℃.

[0042] The third aspect of the present application provides the application of the heat-conducting porous ceramic atomization core in an electronic cigarette.

[0043] Compared with the prior art, the present application has at least the following beneficial effects:

[0044] The heat-conducting porous ceramic atomization core provided by the present application adopts a "sandwich structure" to arrange the first heat-conducting layer and the second heat-conducting layer on both sides of the intermediate layer, so that the bending deformation does not occur even if the ceramic shrinks due to the different materials of the layers. Under the same atomization power, the atomization surface temperature of the heat-conducting porous ceramic atomization core provided by the present application is increased by 15-30 DEG C, the atomization amount is increased by 30-60%, the taste is full and continuous in the front, middle and rear stages, and the ceramic body does not bend and deform.

[0045] The preparation method provided by the present application can sinter the three-layer structure of the atomization core at one time through the co-sintering process, and then further print the electrode, so that the heat-conducting porous ceramic atomization core device with a composite structure is prepared. The preparation method can simplify the preparation process, improve the efficiency, and is suitable for large-scale industrial production.

[0046] The heat-conducting porous ceramic atomization core provided by the present application provides an atomization core with better performance for an electronic cigarette, improves the user experience, and promotes the development of the electronic cigarette. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0048] Figure 1 The structure schematic diagram of the porous ceramic atomization core provided for the first embodiment of the present application is shown in the figure.

[0049] Figure 2 The SEM photo provided for the second test example is shown in the figure.

[0050] Figure legend: 1-first heat-conducting layer; 2-intermediate layer; 201-micropore; 3-second heat-conducting layer; 4-electrode. DETAILED DESCRIPTION

[0051] The embodiments of the present application will be described in detail below with reference to the embodiments and examples, but those skilled in the art will understand that the following embodiments and examples are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the examples in the present application, all other examples obtained by those of ordinary skill in the art without making creative efforts are within the scope of protection of the present application.

[0052] The first aspect of the present application provides a heat-conducting porous ceramic atomizing core having a sandwich structure, comprising a first heat-conducting layer, an intermediate layer and a second heat-conducting layer arranged in layers;

[0053] The surface of the first heat-conducting layer or the second heat-conducting layer away from the intermediate layer is provided with an electrode;

[0054] The first heat-conducting layer, the intermediate layer and the second heat-conducting layer are formed by laminating and sintering slurry A, slurry B and slurry A in sequence.

[0055] The heat-conducting porous ceramic atomizing core provided by the present application adopts a "sandwich structure" to arrange the first heat-conducting layer and the second heat-conducting layer on both sides of the intermediate layer, which ensures that the ceramic does not bend and deform even if the materials of the layers are different and cause ceramic shrinkage. Under the same atomizing power, the atomizing surface temperature of the heat-conducting porous ceramic atomizing core provided by the present application is increased by 15-30℃, the atomizing amount is increased by 30-60%, the taste is full and continuous in the front, middle and rear stages, and the ceramic body does not bend and deform.

[0056] Further, the slurry A comprises, in terms of mass fraction, 35-45 parts of heat-conducting ceramic aggregate, 10-20 parts of first pore-forming agent, 20-35 parts of first organic solvent, 15-25 parts of first binder and 0.5-1.5 parts of first dispersing agent. In some embodiments of the present application, the weight fraction of the heat-conducting ceramic aggregate in the slurry A is typically but not limited to 35 parts, 37 parts, 39 parts, 41 parts, 43 parts or 45 parts.

[0057] Preferably, the slurry B comprises, in terms of mass fraction, 35-45 parts of large-particle ceramic aggregate, 10-20 parts of second pore-forming agent, 20-30 parts of second organic solvent, 15-25 parts of second binder and 0.5-1.5 parts of second dispersing agent. In some embodiments of the present application, the weight fraction of the large-particle ceramic aggregate in the slurry B is typically but not limited to 35 parts, 37 parts, 39 parts, 41 parts, 43 parts or 45 parts.

[0058] Further, the particle size of the heat-conductive ceramic aggregate is 20-80 μm. When the particle size of the heat-conductive ceramic aggregate is less than 20 μm, the sintered ceramic is dense, the amount of mist is reduced, and the aroma and sweetness of the taste are further affected. When the particle size of the heat-conductive ceramic aggregate is greater than 80 μm, the formed pores are too large, the heat transfer effect is affected, the amount of tobacco oil misting is large and concentrated, and the oil explosion phenomenon is easily generated, which affects the smoking experience. In some embodiments of the present application, the particle size of the heat-conductive ceramic aggregate is typically but not limited to 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, and 80 μm.

[0059] Preferably, the heat-conductive ceramic aggregate comprises a first ceramic aggregate, a second ceramic aggregate, and a first sintering aid;

[0060] The first ceramic aggregate comprises at least one of beryllium oxide, aluminum nitride, silicon carbide, and polycrystalline diamond. The first ceramic aggregate is selected from high-thermal-conductivity ceramic materials. The high-thermal-conductivity ceramic materials and the large-particle ceramic aggregate are both ceramic materials, have similar sintering temperatures and physical and chemical properties, and are used together to solve the problems of insufficient atomization effect of the atomization surface of the porous ceramic atomization core and low atomization temperature.

[0061] The second ceramic aggregate comprises silicon dioxide. The second ceramic aggregate is a traditional ceramic aggregate, which is typically but not limited to silicon dioxide.

[0062] The first sintering aid comprises glass.

[0063] Further, the particle size of the large-particle ceramic aggregate is 30-100 μm. The purpose of the layer structure is to better conduct and store tobacco oil. When the particle size of the large-particle ceramic aggregate is less than 30 μm, the formed pore structure is too small, the rate of conducting tobacco oil and flavor is too slow, the amount of surface tobacco oil misting is reduced, and the smoking experience is dry or even has a paste taste. When the particle size of the large-particle ceramic aggregate is greater than 100 μm, the formed pore size is relatively large, the oil conduction rate is relatively fast, and the oil explosion and flying oil phenomenon are easily generated. In addition, the large particle size affects the overall strength of the ceramic, and the phenomenon of powder falling is easily generated, which needs to be further adjusted in the manufacturing process. In some embodiments of the present application, the particle size of the large-particle ceramic aggregate is typically but not limited to 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm.

[0064] Preferably, the large-particle ceramic aggregate comprises a third ceramic aggregate and a second sintering aid;

[0065] The third ceramic aggregate comprises at least one of corundum, diatomite, and quartz.

[0066] The second sintering aid comprises glass.

[0067] Further, the first pore-forming agent or the second pore-forming agent is each independently selected from at least one of plastic beads, fibers, and starch.

[0068] Preferably, the average particle size of the first pore-forming agent is 50-100 μm. When the average particle size of the first pore-forming agent is less than 50 μm, the sintered ceramic is dense, reducing the amount of mist, affecting the taste; when the average particle size of the first pore-forming agent is greater than 100 μm, the formed pores are too large, affecting the heat transfer effect, the amount of tobacco oil misting is large and concentrated, and the oil splashing phenomenon is easy to occur, affecting the smoking experience. In some embodiments of the present application, the particle size of the first pore-forming agent is typically but not limited to 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm.

[0069] Preferably, the average particle size of the second pore-forming agent is 80-150 μm. When the average particle size of the second pore-forming agent is less than 80 μm, the formed pore structure is relatively small, and the rate of conducting and storing tobacco oil and flavor is relatively slow, which can reduce the amount of surface layer tobacco oil misting, and the smoking experience is dry or even produces a paste taste; when the particle size of the second pore-forming agent is greater than 150 μm, the formed pore size is relatively large, and the oil conducting rate is relatively fast, which is easy to appear the oil splashing phenomenon. In some embodiments of the present application, the particle size of the second pore-forming agent is typically but not limited to 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, or 150 μm.

[0070] Further, the first organic solvent or the second organic solvent is each independently selected from at least one of toluene, ethanol, and xylene.

[0071] Preferably, the first binder or the second binder comprises a PVB dispersion liquid.

[0072] Preferably, the solid content of the PVB dispersion liquid is 12-20%. When the solid content of the PVB dispersion liquid is less than 12%, the cast film strip has poor adhesion and toughness, which is difficult to meet the requirements of lamination, and is easy to crack and powder; when the solid content of the PVB dispersion liquid is greater than 20%, the film strip has too much adhesion, and the flattened sample after lamination will have a large deformation, and the later degassing time needs to be longer, otherwise it is easy to delaminate. In some embodiments of the present application, the solid content of the PVB dispersion liquid is typically but not limited to 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%.

[0073] Preferably, the first dispersant or the second dispersant is each independently selected from castor oil and / or triolein.

[0074] The second aspect of the present application provides a preparation method of the heat-conducting porous ceramic atomizing core, comprising the following steps:

[0075] a. respectively, the slurry A and the slurry B are thick film casting to obtain green film strips A and B;

[0076] b. respectively, the green film strips A and B are stacked to obtain a first heat-conducting layer and a second heat-conducting layer, and the green film strip B is stacked to obtain an intermediate layer, and the first heat-conducting layer, the intermediate layer, and the second heat-conducting layer are stacked in order, and then flattened and compacted to obtain a heat-conducting porous ceramic atomization core green body;

[0077] c. the heat-conducting porous ceramic atomization core green body is debinded and first sintered to obtain a heat-conducting porous ceramic atomization core substrate;

[0078] d. the heat-conducting porous ceramic atomization core substrate is second sintered after printing an electrode on the surface of the first heat-conducting layer or the second heat-conducting layer away from the intermediate layer to obtain the heat-conducting porous ceramic atomization core.

[0079] The preparation method provided by the present application can sinter the three-layer structure of the atomization core at one time through the co-sintering process, further print an electrode, and prepare a heat-conducting porous ceramic atomization core device with a composite structure. The preparation method can simplify the preparation process, improve the efficiency, and is suitable for large-scale industrial production.

[0080] Further, in step a, the thickness of the green film strips A and B is independently 200 μm-400 μm.

[0081] Preferably, in step b, the thickness of the first heat-conducting layer and the second heat-conducting layer is independently 0.4 mm-1 mm, and the thickness of the intermediate layer is 2 mm-3 mm. When the thickness of the first heat-conducting layer and the second heat-conducting layer is less than 0.4 mm, the heat-conducting and atomization layers are too thin to achieve good heat-conducting effect. When the thickness of the first heat-conducting layer and the second heat-conducting layer is more than 1 mm, the heat-conducting effect is good, but the smoke oil transfer process is slowed down, affecting the atomization effect. When the thickness of the intermediate layer is less than 2 mm, the content of the intermediate layer for conducting and storing smoke oil is low, and the continuous smoking is prone to cause insufficient oil supply, affecting the taste stability during long-time smoking. When the thickness of the intermediate layer is more than 3 mm, the overall size of the cartridge is thick, and the smoking set for carrying the cartridge needs to be redeveloped. In some embodiments of the present application, the thickness of the first heat-conducting layer and the second heat-conducting layer is typically but not limited to 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm; and the thickness of the intermediate layer is typically but not limited to 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, or 3 mm.

[0082] Preferably, in step b, the flattening pressure is 120 kg-140 kg.

[0083] Further, in step c, the temperature of the debinding is 300-550 DEG C, and the time length of the debinding is 5-10 h.

[0084] Preferably, in step c, the temperature of the first sintering is 1000-1400 DEG C, the time length of the first sintering is 10-15 h, and the holding time is 2-3 h.

[0085] Preferably, in step c, the first sintering is carried out in a vacuum state, and the vacuum degree of the first sintering is ≤10 Pa.

[0086] Preferably, in step d, the vacuum degree of the second sintering is ≤10 Pa, and the temperature of the second sintering is 900-1050 DEG C.

[0087] The third aspect of the present application provides the application of the heat-conducting porous ceramic atomizing core in an electronic cigarette.

[0088] The heat-conducting porous ceramic atomizing core provided by the present application provides an electronic cigarette with a better atomizing core, improves the user experience, and promotes the development of electronic cigarettes.

[0089] The present application is further illustrated by specific examples and comparative examples, but it should be understood that these examples are only used for more detailed illustration, and should not be understood as limiting the present application in any form. In the examples and comparative examples of the present application, the raw materials used are not specified, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified, and are conventional products that can be purchased on the market.

[0090] Example 1

[0091] The present embodiment provides a heat-conducting porous ceramic atomizing core, which is prepared according to the following steps:

[0092] 1. According to the heat-conducting ceramic aggregate 45 kg [silicon carbide (D50=40 μm) and diatomite (D50=80 μm) are mixed in a mass ratio of 2:8], fluxing agent glass 4 kg, ethanol 12 kg, toluene 10 kg, ammonium salt dispersant 1 kg, organic plasticizer and defoaming agent 3% are proportioned, and are loaded into a 2.5 L jar mill tank, 2 kg of φ5 mm zirconium balls are added, and the jar mill is run at a speed of 140 r / min for 8 h; 8 kg of 50 μm NMT plastic beads and 17 kg of PVB with a concentration of 20% are added, and the jar mill is continued to run for 3 h, and the mixed slurry A is obtained.

[0093] 2. According to the proportion of diatomite (D50 = 80 μm) 45 kg, glass 4 kg, ethanol 12 kg, toluene 10 kg, ammonium salt dispersant 1 kg, organic plasticizer and defoaming agent 3%, the ingredients are loaded into a 2.5 L jar mill, 2 kg of φ5 mm zirconium balls are added, and the jar mill is run at a speed of 140 r / min for 8 h; 8 kg of 100 μm NMT plastic balls and 17 kg of PVB with a concentration of 20% are added, and the jar mill is continued for 3 h, and the mixed slurry B is obtained.

[0094] 3. The slurry A and the slurry B are respectively cast into thick films on a casting machine, and after drying, film strips A with a thickness of 200 μm and film strips B with a thickness of 300 μm are obtained. The film strips A and the film strips B are cut into square film pieces with a size of 150*150 mm, and square film pieces A and square film pieces B are obtained. Two layers of the square film pieces A are stacked, 10 layers of the square film pieces B are stacked on the two layers of the square film pieces A, and finally two layers of the square film pieces A are stacked. The above-mentioned 14 layers of the square film pieces are placed under a leveling machine, and are leveled at a pressure of 130 kg, a leveling temperature of 80 ℃, and a leveling time of 10 min. A heat-conducting porous ceramic atomizing core green body is obtained.

[0095] 4. The heat-conducting porous ceramic atomizing core green body is subjected to debinding and sintering, the debinding time is 8 h, the sintering time is 10 h, the sintering temperature is 1100 ℃, the holding time is 2.5 h, the sintering atmosphere is vacuum, and the vacuum degree is ≤10 Pa. A heat-conducting porous ceramic atomizing core substrate is obtained, and a structural schematic diagram thereof is shown in FIG. 1. The heat-conducting porous ceramic atomizing core substrate includes a first heat-conducting layer 1, an intermediate layer 2, and a second heat-conducting layer 3 which are stacked, and an electrode 4 is printed on the surface of the first heat-conducting layer 1. A large number of micropores 201 are arranged in the intermediate layer 2, which facilitates the rapid passage of the medium. Figure 1

[0096] 5. The heat-conducting porous ceramic atomizing core substrate obtained above is subjected to electrode printing and sintering, and the electrode 4 is located on the surface of the first heat-conducting layer 1. The electrode slurry used is a nickel-chromium alloy slurry, the sintering temperature is 980 ℃, the holding time is 30 min, the sintering atmosphere is vacuum, and the vacuum degree is ≤10 Pa. A heat-conducting porous ceramic atomizing core is obtained, and the thickness of the atomizing core is 3 mm.

[0097] Examples 2-8

[0098] Examples 2-8 respectively provide a heat-conducting porous ceramic atomizing core. Different from Example 1, in step 1, the silicon carbide (D50 = 40 μm) and the diatomite (D50 = 80 μm) are mixed according to a mass ratio of 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, and 9:1, respectively, and the rest of the raw materials and the method are the same as those of Example 1, which will not be repeated here.

[0099] Example 9

[0100] ​The embodiment provides a heat-conducting porous ceramic atomizing core, wherein, different from the embodiment 1, in step 1, the heat-conducting ceramic aggregate is 45 kg of silicon carbide (D50=40 μm), and the remaining raw materials and methods are the same as those in the embodiment 1, which will not be repeated here.

[0101] Embodiment 10

[0102] The embodiment provides a heat-conducting porous ceramic atomizing core, wherein, different from the embodiment 1, in step 1, the heat-conducting ceramic aggregate is 45 kg of diatomite (D50=80 μm), and the remaining raw materials and methods are the same as those in the embodiment 1, which will not be repeated here.

[0103] Embodiment 11

[0104] The embodiment provides a heat-conducting porous ceramic atomizing core, which is prepared according to the following steps:

[0105] 1, according to the heat-conducting ceramic aggregate 40 kg [aluminum nitride (D50=20 μm) and diatomite (D50=80 μm) are mixed in a mass ratio of 4:6], the sintering aid glass 4 kg, the ethanol 12 kg, the toluene 10 kg, the ammonium salt dispersant 1 kg, the organic plasticizer and the defoaming agent 3%, the proportion is dosed into a 2.5L jar mill tank, the zirconium ball with a diameter of 5 mm is added 2 kg, the jar mill is operated on the jar mill machine at a speed of 140 r / min for 8 h; the NMT plastic small ball with a diameter of 50 μm is added 10 kg, the PVB with a concentration of 15% is added 16 kg, and the jar mill is continuously operated for 3 h, and the mixed slurry A is obtained.

[0106] 2, according to the diatomite (D50=80 μm) 40 kg, the sintering aid glass 4 kg, the ethanol 12 kg, the toluene 10 kg, the ammonium salt dispersant 1 kg, the organic plasticizer and the defoaming agent 3%, the proportion is dosed into a 2.5L jar mill tank, the zirconium ball with a diameter of 5 mm is added 2 kg, the jar mill is operated on the jar mill machine at a speed of 140 r / min for 8 h; the NMT plastic small ball with a diameter of 100 μm is added 10 kg, the PVB with a concentration of 15% is added 20 kg, and the jar mill is continuously operated for 3 h, and the mixed slurry B is obtained.

[0107] 3, the slurry A and the slurry B are respectively thick film cast on a casting machine, and after drying, the film strip A with a thickness of 200 μm and the film strip B with a thickness of 300 μm are obtained. The film strip A and the film strip B are cut into square film pieces with a size of 150*150 mm. Five layers of film pieces A are taken and sequentially stacked, eight layers of film pieces B are taken and sequentially stacked on the two layers of film pieces A, and finally five film pieces A are taken and sequentially stacked. The above-mentioned 18 layers of film pieces are placed under a leveling machine, and are leveled by using a pressure of 130 kg, a leveling temperature of 80 ℃ and a leveling time of 10 min. A heat-conducting porous ceramic atomizing core green body is obtained.

[0108] 4. The green body of the heat-conducting porous ceramic atomizing core is debinded for 8 hours and sintered for 10 hours at a temperature of 1200℃ with a holding time of 2.5 hours in a vacuum atmosphere with a vacuum degree of ≤10 Pa to obtain the heat-conducting porous ceramic atomizing core substrate.

[0109] 5. The heat-conducting porous ceramic atomizing core substrate obtained above is electrode-printed and sintered at a temperature of 980℃ with a holding time of 30 minutes in a vacuum atmosphere with a vacuum degree of ≤10 Pa to obtain the heat-conducting porous ceramic core.

[0110] Examples 12-13

[0111] Examples 12-13 respectively provide a heat-conducting porous ceramic atomizing core, which is different from Example 11 in that the aluminum nitride (D50=20 μm) and diatomite (D50=80 μm) are mixed in a mass ratio of 6:4 and 8:2 respectively in Step 1, and the rest of the raw materials and methods are the same as those of Example 11, which are not described herein again.

[0112] Example 14

[0113] This example provides a heat-conducting porous ceramic atomizing core, which is different from Example 11 in that the heat-conducting ceramic aggregate in Step 1 is all diatomite (D50=80 μm) 40 kg, and the rest of the raw materials and methods are the same as those of Example 11, which are not described herein again.

[0114] Comparative Example 1

[0115] This comparative example provides a ceramic atomizing core, which is different from Example 1 in that two layers of the film piece A are taken and stacked in turn in Step 3, and ten layers of the film piece B are taken and stacked on the two layers of the film piece A to obtain twelve layers of the film piece. The rest of the raw materials and methods are the same as those of Example 1, which are not described herein again.

[0116] Comparative Example 2

[0117] This comparative example provides a ceramic atomizing core, which is different from Example 1 in that Step 1 is not included, and fourteen layers of the film piece B are taken to obtain the green body of the ceramic atomizing core in Step 3. The rest of the raw materials and methods are the same as those of Example 1, which are not described herein again.

[0118] Comparative Example 3

[0119] This comparative example provides a ceramic atomizing core, which is different from Example 1 in that Step 2 is not included, and fourteen layers of the film piece A are taken to obtain the green body of the ceramic atomizing core in Step 3. The rest of the raw materials and methods are the same as those of Example 1, which are not described herein again.

[0120] Test Example 1

[0121] The ceramic atomizing core obtained from Examples 1-14 and Comparative Examples 1-3 was subjected to atomizing surface temperature test, thermal conductivity test and smoke amount test.

[0122] The atomizing surface temperature was tested by using an infrared temperature tester.

[0123] The thermal conductivity test was tested by using a laser thermal conductivity tester, which is a representative flash method in the transient method for measuring the thermal diffusivity of the material. The standard followed is ASTM-E1461, after testing the specific heat capacity and density, the thermal conductivity is calculated.

[0124] The smoke amount test was tested by using a general equipment in the industry, a smoke concentration tester (including TPM). The test principle of the size of the smoke amount (total particulate matter, TPM) is: simulate the process of artificial smoking by using a kind of porous organic material oil absorption sheet, completely absorb each puff of atomized smoke, then weigh the change of the weight of the oil absorption sheet regularly (such as the first 100 puffs), divided by the corresponding number of puffs, the average atomization amount in the detection period can be obtained. The obtained data is shown in Table 1.

[0125] Table 1: Test results of ceramic atomizing core atomizing surface temperature, thermal conductivity, smoke amount of Examples 1-14 and Comparative Examples 1-3

[0126]

[0127] As can be seen from Table 1, the temperature and thermal conductivity of the atomizing surface of the heat-conductive porous ceramic atomizing core added with silicon carbide and aluminum nitride are obviously improved, and the rule is that the thermal conductivity increases with the increase of the amount of the added heat-conductive ceramic material. The thermal conductivity of the ordinary ceramic atomizing core without the heat-conductive layer is 0.04 W / (m·K), the thermal conductivity of the composite ceramic atomizing core prepared after adding silicon carbide can be up to 22.34 W / (m·K), the temperature of the atomizing surface is increased to 235.2℃, the heat-conductive effect is significantly improved, and the average smoke amount is increased from 8.35 mg / puff to 12.10 mg / puff, which is increased by 44.9%. The thermal conductivity of the composite ceramic atomizing core prepared after adding aluminum nitride can be up to 21.87 W / (m·K), the temperature of the atomizing surface is increased to 232.1℃, the heat-conductive effect is also greatly improved, and the average smoke amount is increased from 8.35 mg / puff to 11.75 mg / puff, which is increased by 40.7%. In addition, it can be found through the comparison of the samples that the composite structure ceramic atomizing core prepared by adding heat-conductive ceramic material on one side is difficult to be metalized and printed with electrodes and verify the taste result due to the difference in shrinkage, which causes the ceramic to bend after sintering. Therefore, the ceramic atomizing core with the "sandwich structure" can not only facilitate production, but also ensure the flatness of the ceramic and is not easy to bend and deform. As can be known through the comparison of Comparative Examples 2 and 3, the appropriate amount of added heat-conductive ceramic can obviously improve the thermal conductivity and TPM of the ceramic atomizing core, but the amount is not the more the better, the temperature of the atomizing surface and the thermal conductivity can be very high after using all heat-conductive materials, but the TPM will be slightly reduced. The optimal amount of different heat-conductive materials is not the same, which needs to be verified by designing experiments.

[0128] Test Example 2

[0129] The heat-conductive porous ceramic atomizing core obtained in Example 1 was subjected to SEM, and the obtained picture is shown in Figure 2 .

[0130] The SEM of the side surface of the heat-conductive porous ceramic atomizing core with 30 times magnification can find that the atomizing core matrix with the stacked structure does not bend, and the fine particles of the upper and lower surface layers and the large particles of the middle layer can be clearly distinguished, as shown in Figure 2 , forming a typical "sandwich structure".

[0131] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A thermally conductive porous ceramic atomizing core, characterized in that, It has a sandwich structure, including a first heat-conducting layer, an intermediate layer and a second heat-conducting layer stacked together; An electrode is provided on the surface of the first or second thermally conductive layer away from the intermediate layer; The first thermally conductive layer, the intermediate layer, and the second thermally conductive layer are respectively formed by laminating and sintering slurry A, slurry B, and slurry A after casting.

2. The thermally conductive porous ceramic atomizing core according to claim 1, characterized in that, The slurry A comprises, by weight, 35-45 parts of thermally conductive ceramic aggregate, 10-20 parts of a first pore-forming agent, 20-35 parts of a first organic solvent, 15-25 parts of a first binder, and 0.5-1.5 parts of a first dispersant. Alternatively, the slurry B may include 35-45 parts by weight of large-particle ceramic aggregate, 10-20 parts by weight of second pore-forming agent, 20-30 parts by weight of second organic solvent, 15-25 parts by weight of second binder, and 0.5-1.5 parts by weight of second dispersant. The particle size of the large ceramic aggregate is 30μm-100μm.

3. The thermally conductive porous ceramic atomizing core according to claim 2, characterized in that, The particle size of the thermally conductive ceramic aggregate is 20μm-80μm.

4. The thermally conductive porous ceramic atomizing core according to claim 2, characterized in that, The thermally conductive ceramic aggregate includes a first ceramic aggregate, a second ceramic aggregate, and a first sintering aid; The first ceramic aggregate includes at least one of beryllium oxide, aluminum nitride, silicon carbide, and polycrystalline diamond; The second ceramic aggregate includes silicon dioxide; The first sintering aid includes glass.

5. The thermally conductive porous ceramic atomizing core according to claim 2, characterized in that, The large-particle ceramic aggregate includes a third ceramic aggregate and a second sintering aid. The third ceramic aggregate includes at least one of corundum, diatomite and quartz. The second sintering aid includes glass.

6. The thermally conductive porous ceramic atomizing core according to claim 2, characterized in that, The first pore-forming agent and the second pore-forming agent are each independently selected from at least one of plastic microspheres, fibers and starch.

7. The thermally conductive porous ceramic atomizing core according to claim 6, characterized in that, The average particle size of the first pore-forming agent is 50μm-100μm.

8. The thermally conductive porous ceramic atomizing core according to claim 6, characterized in that, The average particle size of the second pore-forming agent is 80μm-150μm.

9. The thermally conductive porous ceramic atomizing core according to claim 2, characterized in that, The first organic solvent and the second organic solvent are each independently selected from at least one of toluene, ethanol and xylene.

10. The thermally conductive porous ceramic atomizing core according to claim 2, characterized in that, The first or second adhesive comprises a PVB dispersion.

11. The thermally conductive porous ceramic atomizing core according to claim 10, characterized in that, The solid content of the PVB dispersion is 12%-20%.

12. The thermally conductive porous ceramic atomizing core according to claim 2, characterized in that, The first dispersant and the second dispersant are each independently selected from castor oil and / or trioleic acid glycerides.

13. A method for preparing a thermally conductive porous ceramic atomizing core according to any one of claims 1-12, characterized in that, Includes the following steps: a. Thick film casting is performed on slurry A and slurry B respectively to obtain green film tape A and green film tape B; b. Stack the green film belt A to obtain the first thermally conductive layer and the second thermally conductive layer respectively, and stack the green film belt B to obtain the intermediate layer. Stack the green film belts in the order of the first thermally conductive layer, the intermediate layer and the second thermally conductive layer, and then level and compact them to obtain the thermally conductive porous ceramic atomizing core green blank. c. Degrease and first sinter the thermally conductive porous ceramic atomizing core green body to obtain a thermally conductive porous ceramic atomizing core matrix; d. After printing electrodes on the surface of the first or second thermally conductive layer away from the intermediate layer on the thermally conductive porous ceramic atomizing core substrate, a second sintering is performed to obtain the thermally conductive porous ceramic atomizing core.

14. The preparation method according to claim 13, characterized in that, In step a, the thicknesses of the biofilm generation belt A and the biofilm generation belt B are each independently 200μm-400μm.

15. The preparation method according to claim 13, characterized in that, In step b, the thickness of the first thermally conductive layer and the second thermally conductive layer are each 0.4mm-1mm, and the thickness of the intermediate layer is 2mm-3mm.

16. The preparation method according to claim 13, characterized in that, In step b, the leveling pressure is 120kg-140kg.

17. The preparation method according to claim 13, characterized in that, In step c, the degreasing temperature is 300℃-550℃, and the degreasing time is 5h-10h.

18. The preparation method according to claim 13, characterized in that, In step c, the temperature of the first sintering is 1000℃-1400℃, the duration of the first sintering is 10h-15h, and the holding time is 2h-3h.

19. The preparation method according to claim 13, characterized in that, In step c, the first sintering is performed under vacuum, and the vacuum degree of the first sintering is ≤10Pa.

20. The preparation method according to claim 13, characterized in that, In step d, the vacuum degree of the second sintering is ≤10Pa, and the temperature of the second sintering is 900℃-1050℃.

21. The application of the thermally conductive porous ceramic atomizing core according to any one of claims 1-12 in electronic cigarettes.

Images