CN115104765A

CN115104765A - Atomizing core, preparation method of composite porous ceramic matrix for atomizing core and electronic atomizing device

Info

Publication number: CN115104765A
Application number: CN202110295143.XA
Authority: CN
Inventors: 刘双任; 江品颐; 黄永河; 林信平; 杨伟强
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2021-03-19
Filing date: 2021-03-19
Publication date: 2022-09-27

Abstract

The application provides an atomizing core, which comprises a composite porous ceramic matrix and a heating body arranged on the composite porous ceramic matrix, wherein the composite porous ceramic matrix is provided with a liquid absorbing surface and an atomizing surface which are oppositely arranged and comprises a first porous ceramic body and a second porous ceramic body which are connected, and the second porous ceramic body and the heating body are both close to the atomizing surface; wherein the average pore size of the first porous ceramic body is greater than the average pore size of the second porous ceramic body, the pores in the first porous ceramic body comprise spherical pores and fibrous pores, and the pores in the second porous ceramic body are of a single morphology. By means of the multi-section composite porous ceramic matrix with different pore shapes and pore diameters, the atomizing core can realize a fast and excellent atomizing effect and has good mechanical strength.

Description

Atomizing core, preparation method of composite porous ceramic matrix for atomizing core and electronic atomizing device

Technical Field

The application relates to the technical field of ceramic atomizing cores, in particular to an atomizing core, a preparation method of a composite porous ceramic matrix for the atomizing core and an electronic atomizing device.

Background

The atomizing core is an important component in an electronic cigarette product, mainly comprises a porous ceramic matrix and a heating body arranged on the porous ceramic matrix, and can heat and atomize the tobacco tar under the electric heating action of the heating body by utilizing the porous ceramic matrix to adsorb the tobacco tar to the heating body. Wherein, the conduction velocity, the atomization effect and the like of the tobacco tar in the atomization core are closely related to the porous ceramic matrix. At present, the shape of a hole in a commonly used porous ceramic matrix is single, the aperture is mostly fixed, the communication degree between the holes is poor, the probability of the existence of a blind hole is high, and therefore, the atomizing core cannot give consideration to the high tobacco tar conduction speed and the excellent tobacco tar atomization effect.

Disclosure of Invention

In view of this, the present application provides an atomizing core and a method for preparing a porous ceramic matrix using the same, which can make the tobacco tar be quickly conducted to the heating element and be sufficiently atomized by controlling the pore size of the porous ceramic matrix section near the liquid suction surface to be larger than that of the porous ceramic matrix section near the atomizing surface, and the pore shapes to be various.

In a first aspect, the application provides an atomizing core, which comprises a composite porous ceramic matrix and a heating element arranged on the composite porous ceramic matrix, wherein the composite porous ceramic matrix is provided with a liquid absorbing surface and an atomizing surface which are oppositely arranged, and the heating element is close to the atomizing surface; the composite porous ceramic matrix comprises a first porous ceramic body and a second porous ceramic body which are arranged in a stacked mode, wherein the second porous ceramic body is close to the atomizing surface, the average pore diameter of the first porous ceramic body is larger than that of the second porous ceramic body, pores in the first porous ceramic body comprise spherical pores and fibrous pores, and the pores in the second porous ceramic body are in a single shape.

According to the atomizing core provided by the first aspect of the application, the first porous ceramic body far away from the heating element is controlled to have holes with various shapes and large pore diameters compared with the second porous ceramic body close to the heating element, so that the communication degree of the holes in the first porous ceramic body and the conduction speed of tobacco tar can be increased, and the mechanical strength of the atomizing core is not reduced; the second porous ceramic body close to the heating body has small aperture and low diversity of pore shapes, which is beneficial to the concentration of heat generated by the heating body and ensures that the tobacco tar is atomized fully and finely. Therefore, the atomizing core can realize fast and excellent atomizing effect and simultaneously has good mechanical strength.

In a second aspect, the present application provides a method for preparing a composite porous ceramic matrix for an atomizing core, comprising the steps of:

preparing a first green body, wherein the first green body comprises a first ceramic aggregate, a first pore-forming agent and a first binder;

preparing a second green body, and stacking the second green body and the first green body to obtain a composite green body, or preparing the second green body on the first green body; the second green body comprises a second ceramic aggregate, a second pore-forming agent and a second binder; the first pore-forming agent comprises a first spherical pore-forming agent and a fibrous pore-forming agent; the second pore-forming agent has a single shape; the particle size of the first spherical pore-forming agent and the length of the fibrous pore-forming agent are both larger than the particle size of the second pore-forming agent;

and sintering the composite green body to obtain the composite porous ceramic matrix.

According to the preparation method of the atomization core provided by the second aspect of the application, the composite porous ceramic matrix formed by sintering the stacked structure of the green body has a high smoke oil conduction speed and a sufficient atomization effect at the same time by preparing the first green body containing the first pore-forming agent with a large particle size and various shapes and the second green body containing the second pore-forming agent with a small particle size and a single shape. The preparation method has simple process and easy operation, and is beneficial to large-scale preparation.

Due to the adoption of the atomization core, the electronic atomization device can quickly generate smoke with good taste and high plumpness during working, the user experience is good, the mechanical performance of the electronic atomization device is good, and the service life is long.

Drawings

FIG. 1 is a schematic structural view of an atomizing core according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a composite porous ceramic matrix in an atomizing core.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

The embodiment of the application provides an atomizing core, which can be used in electronic atomizing devices such as electronic cigarettes. Referring to fig. 1 to 2 together, an atomizing core 100 according to an embodiment of the present application includes a composite porous ceramic base 10 and a heating element 20 disposed on the composite porous ceramic base 10. The composite porous ceramic base 10 is used to suck and transfer a liquid medium (hereinafter, smoke is described as a representative), and the heating element 20 is used to heat and atomize the liquid medium sucked by the composite porous ceramic base 10.

Referring to fig. 2, the composite porous ceramic base 10 has a liquid absorbing surface 101 and an atomizing surface 102 which are oppositely arranged, the heating element 20 is arranged close to the atomizing surface 102, the composite porous ceramic base 10 includes a first porous ceramic body 11 and a second porous ceramic body 12 which are arranged in a stacked manner, the first porous ceramic body 11 is close to the liquid absorbing surface 101, and the second porous ceramic body 12 is close to the atomizing surface 102; wherein the average pore size of the first porous ceramic body 11 is larger than the average pore size of the second porous ceramic body 12, and the pores in the first porous ceramic body 11 include spherical pores 111 and fibrous pores 112; the pores in second porous ceramic body 12 are of a single morphology.

Based on the existence of pores having various morphologies in the first porous ceramic body 11 at the same time, particularly fibrous pores (i.e., elongated pores having a circular or quasi-circular cross section), the probability of communication between spherical pores can be significantly increased, thereby making the communication between the pores higher and the closed porosity low, and at the same time, the pore size in the first porous ceramic body 11 larger, so that the transfer rate of the soot in the first porous ceramic body 11 can be made faster and the soot can rapidly reach the second porous ceramic body 12 close to the heating element. And, because the size of the hole is relatively less, the appearance variety is low in second porous ceramic body 12, do benefit to the heat of heat generation body and guarantee that the tobacco tar is fully atomized, the atomizing fineness is high. In addition, the presence of the fibrous pores 112 does not reduce the mechanical strength of the composite porous ceramic substrate 10. Therefore, by controlling the different pore characteristics in different regions of the composite porous ceramic body 10, the atomizing core 100 can achieve a fast and excellent atomizing effect and has good mechanical strength.

The cross-sectional shape (or opening shape) of the spherical pores and the fibrous pores is usually circular or quasi-circular, and the pore diameter refers to the diameter of the circle. In particular, the extended length (i.e., the pore depth) of the fibrous pores is longer, which makes it easier to communicate between the spherical pores 111 in the first porous ceramic body 11, increasing the connectivity of the pores in the first porous ceramic body 11.

In the present embodiment, the pores in the second porous ceramic body 12 have a single morphology, and at this time, the connectivity between the pores in the second porous ceramic body 12 is lower than that in the first porous ceramic body 11, which is more favorable for concentrating the heat generated by the heating element. Wherein the pores in the second porous ceramic body 12 may be spherical pores, or fibrous pores, etc. Preferably, to provide the first porous ceramic body 11 with good mechanical strength, the pores in the second porous ceramic body 12 are spherical pores (as shown in FIG. 2). For the sake of distinction, the spherical pores 111 in the first porous ceramic body 11 may be referred to as first spherical pores 111. The spherical pores 120 in the second porous ceramic body 12 are referred to as second spherical pores 120.

In the present application, the average pore size of first porous ceramic body 11 is larger than the average pore size of second porous ceramic body 12. Alternatively, the average pore size of the first porous ceramic body 11 is 15-40 μm. Second porous ceramic body 12 has an average pore size of 8 to 20 μm. Thus, the tobacco tar is conducted at a high speed in the first porous ceramic body 11 having a large average pore diameter, and is atomized well in the second porous ceramic body 12 having a small average pore diameter near the heating element. Preferably, the average pore diameter of the first porous ceramic body 11 is 20 to 40 μm, and more preferably 30 to 35 μm. Preferably, second porous ceramic body 12 has an average pore size of 10 to 20 μm, more preferably 10 to 15 μm.

Further optionally, the aperture of the first spherical hole 111 is larger than the aperture of the second spherical hole 120. Wherein, the number of the first spherical pores 111 with a pore diameter of 20-40 μm (i.e. the pore diameter is the average pore diameter) is 90% or more. At this time, the first spherical pores in the first porous ceramic body 11 have a high degree of pore diameter uniformity. Similarly, the number of the second spherical pores 120 having a pore diameter of 10 to 20 μm (i.e., a pore diameter value of an average pore diameter) is 90% or more of the second spherical pores 120.

Alternatively, the fibrous pores 112 have a pore diameter of 2-20 μm and a length (i.e., depth) of 30-200 μm.

In some embodiments, the first porous ceramic body 11 has a number of fibrous pores 112 that is 2% to 10% of the number of first spherical pores 111. The ratio of the number of pores in the two shapes is controlled within this range, so that the first porous ceramic body 11 has a faster oil guiding speed without excessively impairing the mechanical strength. Preferably, the number of fibrous pores 112 in the first porous ceramic body 11 is 2.5% to 6%, more preferably 3% to 6%, of the number of first spherical pores 111.

In the present embodiment, the total porosity (both open and closed pores counted) of the first porous ceramic body 11 is greater than or equal to the total porosity of the second porous ceramic body 12; the closed porosity of the first porous ceramic body 11 is less than the closed porosity of the second porous ceramic body 12.

Closed porosity is the difference between total porosity and open porosity. The expression "open porosity" refers to the percentage of the volume of pores in a porous material that can be saturated with water (i.e., filled with water) relative to the volume of the porous material in its natural state. That is, the open porosity of the first porous ceramic body 11 is also larger than the open porosity of the porous ceramic body 12. When the total porosity of the first porous ceramic matrix 10 is kept constant, the lower the closed porosity thereof, which means that the number of corresponding open pores is larger, the higher the communication degree between the pores is, and the better the conduction velocity of the soot therein is increased.

In the present embodiment, the total porosity of the first porous ceramic body 11 is greater than or equal to the total porosity of the second porous ceramic body 12. At this time, the density of the second porous ceramic body 12 is relatively high, and the thermal conductivity is also relatively high, which is beneficial to concentrating the heat generated by the heating body 20 on the second porous ceramic body 12, thereby improving the atomization effect and reducing the energy consumption. Alternatively, the total porosity of the first porous ceramic body 11 is between 50-65%. The total porosity of second porous ceramic body 12 is 40-55%.

In some embodiments, the first porous ceramic body 11 has a closed porosity of 4% or less, preferably 3% or less. The closed porosity of the second porous ceramic body 12 ranges from 4% to 10%. Optionally, the first porous ceramic body 11 has a pore connectivity of 95% or more, and the second porous ceramic body 12 has a pore connectivity of 80-95%.

Therefore, the first porous ceramic body 11 is controlled to have the characteristics of large pore size, high total porosity and high open porosity, so that the first porous ceramic body has a larger oil storage capacity and a faster oil guiding rate. Controlling the second porous ceramic body 12 to have the above-described characteristics of small pore size, low total porosity, and low open porosity can facilitate the tobacco tar to reach the desired atomization temperature and to be converted into smoke with a fine mouth feel.

In the present embodiment, the ratio of the thickness of the first porous ceramic body 11 to the thickness of the second porous ceramic body 12 is 1: (0.3-3). Under the above thickness ratio range, the atomizing core 100 can better give consideration to faster tobacco tar conduction speed, better atomizing effect and good mechanical strength. The thicknesses of the first porous ceramic body 11 and the second porous ceramic body 12 may be adjusted according to the respective mesopores, porosities, etc., and preferably, the thickness of the first porous ceramic body 11 is less than or equal to the thickness of the second porous ceramic body 12, so that the atomizing core 100 has higher mechanical strength. In some embodiments, the first porous ceramic body 11 has a thickness of 0.5 to 3mm, specifically but not limited to 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 2nmm, or 3 mm. The thickness of the second porous ceramic body 12 may be 1-3mm, specifically but not limited to 1mm, 1.2mm, 1.5mm, 2nmm or 3 mm.

In the present embodiment, the first porous ceramic body 11 may be integrally formed with the second porous ceramic body 12, and no additional connection therebetween may be required. Wherein the two may be in a stacked arrangement (e.g., the second porous ceramic body 12 disposed on the surface of the first porous ceramic body 11) or in a partially embedded relationship, e.g., the second porous ceramic body 12 partially embedded within the first porous ceramic body 11.

In this application, heat-generating body 20 is provided with a plurality of holes that run through, and it has certain resistance, can produce the heat under the on-state, and then can make the tobacco tar of being close to this heat-generating body 20 department take place to atomize. In some embodiments, the heat generating body 20 may be a sheet metal, which may be laid on the surface of the composite porous ceramic substrate 10 (as shown in fig. 1), embedded or partially embedded in the composite porous ceramic substrate 10. In another embodiment, the heat generating element 20 may be a conductive paste screen-printed on the composite porous ceramic substrate 10, and may be formed by sintering, and the screen-printed heat generating element 20 may be attached to the surface of the composite porous ceramic substrate 10 as shown in fig. 1.

The above-mentioned atomizing core that this application embodiment provided carries out the control of above-mentioned different pore characteristics through the different regions to compound porous ceramic base member, can make atomizing core under the condition that has good mechanical strength, can also realize higher oil rate, better atomization effect of leading.

In some embodiments of the present application, the atomization core has an oil delivery rate of 0.6mg/s to 2.5 mg/s. In some embodiments, the atomizing core has an oil delivery rate of 0.8mg/s to 1.5mg/s, preferably 0.8mg/s to 1.2 mg/s.

In embodiments of the present application, the oil locking capacity of the atomizing core is above 40%, and in some embodiments, the oil locking capacity of the atomizing core is above 60%, preferably above 80%, more preferably above 85%, for example 85% -99%.

In some embodiments of the present application, the crush strength of the atomizing core is 15MPa or more, preferably 18MPa or more. In other embodiments, the crush strength of the atomizing core is from 18 to 25 MPa.

The embodiment of the application also provides a preparation method of the composite porous ceramic matrix for the atomizing core, which comprises the following steps:

The composite porous ceramic base body comprises a first porous ceramic body and a second porous ceramic body which are integrally formed, the first porous ceramic body is formed by sintering the first green body, and the second porous ceramic body is formed by sintering the second green body.

According to the preparation method of the composite porous ceramic matrix, the first green body containing the first pore-forming agent with larger particle size and various appearance and the second green body containing the second pore-forming agent with smaller particle size and single appearance are respectively prepared, so that the composite porous ceramic matrix formed by sintering the stacked structures of the two green bodies has higher smoke oil conduction speed and more sufficient atomization effect. The preparation method has simple process and is beneficial to large-scale preparation of the multi-section composite porous ceramic matrix with different pore characteristics.

The fibrous pore former is used to form fibrous pores in the sintered first porous ceramic body from the first green body. Optionally, the length of the fibrous pore-forming agent is 50-300 μm; the diameter is 5-30 μm. The fibrous pore-forming agent with proper length can not affect the forming effect of the first blank, and can effectively improve the pore connectivity of the first porous ceramic body sintered by the first blank and not remarkably reduce the mechanical strength of the first porous ceramic body. Optionally, the length of the fibrous pore former is 5 to 30 times, preferably 5 to 20 times, its diameter.

The first spherical pore-forming agent is used for forming first spherical holes with larger pore diameters in the first porous ceramic body sintered from the first green body. Optionally, the particle size of the first spherical pore-forming agent is 20-60 μm, preferably 22-60 μm, more preferably 22-45 μm, more preferably 25-40 μm, and most preferably 30-35 μm.

In an embodiment of the present application, the second pore-forming agent is a pore-forming agent with a single morphology. In some embodiments, the second pore former is a spherical pore former (which may be referred to as a second spherical pore former). At this time, the second spherical pore-forming agent is used to form second spherical pores having a smaller pore size in the second porous ceramic body sintered from the second green body. Optionally, the particle size of the second pore-forming agent is 12-30 μm. Preferably, the particle size of the second pore-forming agent is 15 to 30 μm, and more preferably 15 to 25 μm.

In an embodiment of the present application, in the first pore-forming agent, the mass of the first spherical pore-forming agent is 1.1 to 3 times of the mass of the fibrous pore-forming agent. At this time, the first porous ceramic body sintered from the first green body has a suitable number ratio of spherical pores to fibrous pores, so that the first porous ceramic body has a suitable mechanical strength when having a high pore communication rate.

Optionally, in the first blank, the mass ratio of the first pore-forming agent is 10% to 35%. The quality of the first pore-forming agent is controlled within the range, the porosity of the first porous ceramic body sintered by the first blank is not larger, so that the atomizing core is prevented from leaking oil and the mechanical strength is not deviated, and the oil guide is not smooth due to the too small porosity, so that the atomizing performance is not influenced. Optionally, the mass of the first pore-forming agent is 12% -30% of the mass of the first ceramic aggregate. At this time, the first porous ceramic body sintered from the first green body has a suitable porosity.

In some embodiments of the present disclosure, the first body may further include a first dispersant to improve the dispersibility of the components in the first body.

Optionally, the first blank may include the following components in percentage by mass: 65-85% of first ceramic aggregate, 6-20% of first spherical pore-forming agent, 4-15% of fibrous pore-forming agent, 2-10% of first binder and 0.1-3% of first dispersing agent.

Similarly, the second pore-forming agent is present in the second green body in a proportion of 5% to 25% by mass, for example 10% to 25% by mass. Therefore, the second porous ceramic body sintered by the second green body also has proper porosity, and the integral atomizing core has good mechanical strength and atomizing effect. Optionally, the mass of the second pore-forming agent is 15% to 35%, for example 15% to 23%, of the mass of the second ceramic aggregate. Optionally, the second body may also contain a second dispersant to achieve better dispersion of the components. Wherein the first dispersing agent and the second dispersing agent are independently selected from one or more of sodium carboxymethylcellulose, ammonium polymethacrylate, triethanolamine, silane and the like.

Optionally, the second blank may include the following components in percentage by mass: 65-85% of second ceramic aggregate, 5-25% of second pore-forming agent, 2-10% of second binder and 0.1-3% of second dispersing agent.

In the present application, the first body or the second body may be independently prepared by a dry press molding method or a slip casting method, but is not limited thereto. The dry pressing method is to dry press the granulation powder containing the corresponding raw materials under a certain pressure, wherein the granulation powder can be obtained by spray drying the mixed slurry containing the raw materials and the solvent, or the mixed powder containing the raw materials is obtained by banburying and granulating by a granulator through a mixer. The slip casting may be performed by injecting a mixed slurry obtained by heating a mixed powder containing the respective raw materials into a mold at a predetermined temperature and pressure or into a mold having a heating element placed therein.

In some embodiments of the present application, a first green body is formed by dry pressing and a second green body is formed by dry pressing on the second green body. At the moment, the preparation of two blanks can be realized through one die, the cost is low, the efficiency is high, and the appearance of each blank is well maintained. Optionally, the molding pressure when preparing the first blank is 20-50 MPa; the molding pressure when preparing the second blank is 80-140 MPa. The pressure of the latter is larger than that of the former, so that the bonding force between the first green body and the second green body can be improved when the second green body is well formed.

In the present embodiment, the fibrous pore-forming agent may be at least one selected from carbon fiber, graphite fiber, aramid fiber, silk, wool, and the like, but is not limited thereto. Preferably, the fibrous pore former is selected from at least one of carbon fiber, graphite fiber and aramid fiber. The first spherical pore-forming agent and the second spherical pore-forming agent are independently selected from one or more of inorganic carbon powder, natural organic particles and organic microspheres. Specifically, the inorganic carbon powder may include one or more of spherical graphite, carbon black, activated carbon, and the like. The natural organic matter particles may include starch particles, sawdust, and the like. The organic microspheres may also be referred to as "high molecular polymer microspheres," and may include polymethyl methacrylate (PMMA) microspheres, Polystyrene (PS) microspheres, polyvinyl alcohol (PVA) microspheres, and the like. In some embodiments of the present application, the first spherical pore-forming agent and the second spherical pore-forming agent are independently selected from one or more of spherical graphite powder, spherical carbon powder, starch particles, PMMA microspheres, PS microspheres.

The first ceramic aggregate and the second ceramic aggregate are framework materials of the composite porous ceramic matrix, and certain mechanical strength is guaranteed. Wherein, the first ceramic aggregate and the second ceramic aggregate can be independently selected from one or more of glass powder, silicon carbide, silicon nitride, silicon oxide, aluminum oxide, zirconium oxide, titanium oxide and the like.

The first binder can be used for improving the binding force among the raw materials in the first green body and improving the forming effect of the first green body. Wherein the first binder is at least one selected from polyvinyl alcohol, carboxymethyl cellulose, polyethylene glycol, acrylic binder, and the like. The function and material selection range of the second adhesive are similar to those of the first adhesive.

In some embodiments of the present application, the first green body may be prepared by the following dry forming method:

preparing first ceramic slurry containing first ceramic aggregate, a first pore-forming agent, a first binder and a first solvent;

performing spray drying treatment on the first ceramic slurry to obtain first granulation powder;

and pressing the first granulated powder into the first green body.

Wherein the first ceramic slurry further contains a first dispersant. Preferably, the first ceramic slurry is formulated by:

firstly, mixing a fibrous pore-forming agent with a first dispersing agent and a first solvent to obtain a dispersion liquid of the fibrous pore-forming agent; and mixing the dispersion of the fibrous pore-forming agent with a first ceramic aggregate, a first spherical pore-forming agent, a first dispersing agent, a first binder and a first solvent to obtain the first ceramic slurry.

When the first ceramic slurry is prepared, the fibrous pore-forming agent is dispersed and then is mixed with other raw materials, so that the dispersibility of the fibrous pore-forming agent can be improved, the dispersion degree between the fibrous pore-forming agent and the first spherical pore-forming agent can also be improved, and then in the subsequent sintering process, the connectivity among the spherical pores formed by the first spherical pore-forming agent can be improved by fibrous pores formed by the fibrous pore-forming agent, and further the connectivity of each pore in the first porous ceramic blank is improved.

Further, before preparing the dispersion of the fibrous pore-forming agent, the fibrous pore-forming agent may be subjected to at least one surface treatment such as plasma treatment or pre-oxidation treatment to have a functional group such as at least one of carboxyl group, hydroxyl group and the like on its surface, which improves its dispersibility in the dispersant. Wherein, the pre-oxidation treatment can be carried out by the following method: soaking fibrous pore-forming agent (such as carbon fiber) in concentrated sulfuric acid solution, heating to 60-80 deg.C in air, acid-leaching for 30-60 min, naturally cooling to room temperature, taking out the acid-leached fibrous pore-forming agent, and washing the acid solution on the surface.

Similarly, in some embodiments of the present application, the second body is prepared by:

mixing a second ceramic aggregate, a second pore-forming agent, a second binder and a second solvent to obtain a second ceramic slurry;

performing spray drying treatment on the second ceramic slurry to obtain second granulation powder;

and pressing the second granulated powder into the second green body.

Wherein the second ceramic slurry may further contain a second dispersant. The aforementioned first solvent and second solvent may be independently selected from one or more of water, ethanol, ethylene glycol, and the like.

In the embodiment of the application, the sintering temperature for sintering the composite blank can be 1100-1300 ℃, and the heat preservation time is 1-4 h. Specifically, the sintering temperature may be, but is not limited to, 1100 ℃, 1150 ℃, 1200 ℃ or 1300 ℃. The length of incubation may be, but is not limited to, 1h, 2h, 3h or 4 h.

Alternatively, in some embodiments of the present application, if a composite porous ceramic substrate (i.e., an atomizing core) provided with a heat generating body is desired, the foregoing preparation method further includes: and silk-screen printing a heating body on the composite porous ceramic matrix to obtain the atomizing core. Optionally, after the heating element is silk-screened, a post-sintering treatment is usually also included to improve the bonding force between the composite porous ceramic substrate and the heating element. Wherein, the heating element formed by silk screen printing can also be called as a heating circuit and has a porous structure.

In other embodiments of the present application, a heating element (preferably in the form of a sheet) is inserted into the second body on the side thereof remote from the first body before sintering the composite body, resulting in a composite body with an embedded heating element. Thus, after sintering, a composite porous ceramic substrate with a heating element, that is, an atomized core can be obtained. The heat generating body in this case may be a metal sheet having a porous structure or a conductive ceramic. The holes in the metal sheet can be opened by at least one of laser drilling, mechanical punching, mechanical drilling, chemical etching and the like. The porous conductive ceramic can be prepared by sintering ceramic powder or slurry containing conductive powder.

In a third aspect, the present application provides an electronic atomization device, which includes the atomization core described in the present application. The electronic atomization device may be an electronic smoking article.

This electron atomizing device still includes the oil storage subassembly, and the oil storage subassembly includes the oil storage chamber, and the liquid medium such as tobacco tar is stored in the oil storage chamber, and the oil storage chamber can be with the imbibition face lug connection of aforementioned atomizing core. The electronic atomization device can also comprise a power supply assembly, and the power supply assembly is electrically connected with the heating body on the atomization core so as to heat the heating body.

When the electronic atomization device works, smoke oil and the like in the oil storage cavity are guided to the heating body arranged on the oil storage cavity through the composite porous ceramic substrate, and the smoke can be evaporated when the heating body is heated. Due to the adoption of the atomization core, the smoke generated by the electronic atomization device has good taste, the smoke is high in fullness, the mechanical performance of the electronic atomization device is good, and the service life of the electronic atomization device is long.

The present application is further illustrated by the following specific examples.

Example 1

A preparation method of an atomization core comprises the following steps:

(1) preparing a first granulated powder for a first body:

firstly, pre-oxidizing a fibrous pore-forming agent (specifically short carbon fiber with the length of 200 mu m and the diameter of 35 mu m) to enable the surface of the fibrous pore-forming agent to be provided with functional groups such as-COOH and the like, and then mixing pre-oxidized graphite with a 1% sodium carboxymethyl cellulose aqueous solution to obtain a carbon fiber dispersion liquid;

then mixing the dispersion liquid of the carbon fibers with a first ceramic aggregate, a first spherical pore-forming agent, sodium carboxymethyl cellulose and a first binder to obtain a first ceramic slurry; carrying out spray drying treatment on the first ceramic slurry to obtain first granulation powder; the first granulation powder comprises the following raw materials in percentage by mass: 75 wt% of first ceramic aggregate (specifically, alumina and amorphous silica in a mass ratio of 15: 85), 8 wt% of carbon fiber, 12 wt% of first spherical pore-forming agent (starch particles and polymethyl methacrylate microspheres with a particle size of 30 μm, specifically, in a mass ratio of 2: 8), 4.5 wt% of first binder (specifically, polyvinyl alcohol) and 0.5% of sodium carboxymethyl cellulose.

(2) Preparation of a second granulated powder for a second green body:

mixing a second ceramic aggregate, a second pore-forming agent, a second binder, a second dispersing agent and water to obtain a second ceramic slurry; performing spray drying treatment on the second ceramic slurry to obtain second granulation powder;

wherein the second granulation powder comprises the following raw materials in percentage by mass: 75 wt% of second ceramic aggregate (specifically, alumina and glass powder with the melting point of 1100 ℃ in a mass ratio of 15: 85), 20 wt% of second spherical pore-forming agent (starch particles with the particle size of 20 micrometers, specifically, 2: 8 in a mass ratio and polymethyl methacrylate microspheres), 4.5 wt% of second binder (specifically, 7: 1 of acrylic binder and polyvinyl alcohol), and 0.5 wt% of dispersing agent (specifically, a mixture of ammonium polymethacrylate and sodium carboxymethylcellulose).

(3) Preparation of composite green body

Prepressing the first granulation powder in a die, wherein the prepressing pressure is 40-50MPa, and obtaining a first blank body; filling the second granulated powder into a pre-pressed die (namely, enabling the second granulated powder to be positioned on the first green body), and performing dry pressing again under the pressure of 80-90MPa to form a second green body on the first green body so as to obtain a composite green body;

(4) sintering the composite green body at 1100 ℃, and keeping the temperature for 3 hours to obtain a composite porous ceramic matrix; the composite porous ceramic matrix comprises a first porous ceramic body and a second porous ceramic body which are arranged in a laminated mode, wherein the first porous ceramic body is formed by sintering the first green body, and the second porous ceramic body is formed by sintering the second green body;

and then cutting the composite porous ceramic matrix into small blocks, and screen printing a heating body on the second green body to obtain the atomizing core.

The schematic structural view of the atomizing core obtained in example 1 can be shown in fig. 1, and the atomizing core includes a porous ceramic base 10 shown in fig. 2 and a heat-generating body 10 disposed thereon. In the porous ceramic matrix 10, the pores in the first porous ceramic body 11 include spherical pores 111 and fibrous pores 112; the pores in the second porous ceramic body 12 may be spherical pores 120.

Wherein the first porous ceramic body 11 has a thickness of 2mm, an average pore diameter of 25 μm, a total porosity of 60%, a closed porosity of 1.5%, and the number of fibrous pores being 3.2% of spherical pores; the second porous ceramic body 12 has a thickness of 2mm, an average pore diameter of 12 μm, a total porosity of 52%, and a closed porosity of 6%.

Example 2

A method of making an atomizing core comprising the steps of:

(1) preparing a first green body by a dry pressing forming method; the pressure during pressing is 30MPa, and the first blank comprises the following raw materials in percentage by mass: 75 wt% of a first ceramic aggregate (in particular 8: 2 silica and zirconia), 8 wt% of a fibrous pore former (aramid fiber with a length of 200 μm and a diameter of 30 μm), 12 wt% of a first spherical pore former (with a particle size of 30 μm, in particular polymethyl methacrylate microspheres), 4 wt% of a first binder (in particular acrylic binder) and 1% of a first dispersant (in particular ammonium polymethacrylate and silane);

(2) preparing a second blank body on the first blank body by a dry pressing forming method under the pressure of 120MPa to obtain a composite blank body, wherein the second blank body comprises the following raw materials in percentage by mass: 80 wt% of a second ceramic aggregate (specifically 80% of silicon oxide, 10% of aluminum oxide, 10% of titanium oxide), 16 wt% of a second spherical pore-forming agent (particle size of 15 μm, specifically polymethyl methacrylate microspheres), 3 wt% of a second binder (specifically acrylic binder) and 1% of a first dispersant (specifically ammonium polymethacrylate and silane);

(3) sintering the composite green body at 1200 ℃ for 2h to obtain a composite porous ceramic matrix; then, a heating element was screen-printed on the composite ceramic substrate to obtain an atomized core.

In the atomizing core obtained in example 2, the first porous ceramic body 11 had a thickness of 1.5mm, an average pore diameter of 20 μm, a total porosity of 58%, a closed porosity of 2%, and a number of fibrous pores of 4.4% of spherical pores; the second porous ceramic body 12 has a thickness of 2mm, an average pore diameter of 10 μm, a total porosity of 50%, and a closed porosity of 4%.

Example 3

A method of preparing an atomizing core, which differs from example 1 in that: in the first granulated powder, the mass of the first spherical pore-forming agent is not 1.5 times but 1.22 times the mass of the fibrous pore-forming agent. Namely, the first granulated powder includes: 75 wt% of first ceramic aggregate, 11 wt% of first spherical pore-forming agent, 9 wt% of carbon fiber, 4.5 wt% of first binder and 0.5 wt% of sodium carboxymethylcellulose.

In the atomizing core obtained in example 3, the average pore diameter of the first porous ceramic body 11 was 26 μm, the total porosity was 61%, the closed porosity was 1%, and the number of fibrous pores was 5.4% of the spherical pores; the average pore diameter of the second porous ceramic body 12 is 12 μm, the total porosity is 52%, and the closed porosity is 6%.

Example 4

A method of preparing an atomizing core, which differs from example 1 in that: in the first granulated powder, the mass of the first spherical pore-forming agent is not 1.5 times but 3 times the mass of the fibrous pore-forming agent. Namely, the first granulated powder includes: 75 wt% of first ceramic aggregate, 15 wt% of first spherical pore-forming agent, 5 wt% of carbon fiber, 4.5 wt% of first binder and 0.5 wt% of sodium carboxymethylcellulose.

In the atomizing core obtained in example 4, the average pore diameter of the first porous ceramic body 11 was 19 μm, the total porosity was 56%, the closed porosity was 4%, and the number of fibrous pores was 2.2% of the spherical pores; the average pore diameter of the second porous ceramic body 12 is 12 μm, the total porosity is 52%, and the closed porosity is 6%.

Example 5

A method of preparing an atomizing core, which differs from example 1 in that: in the first granulated powder, the mass of the first spherical pore-forming agent is not 1.5 times but 0.5 times the mass of the fibrous pore-forming agent. Namely, the first granulated powder includes: 75 wt% of first ceramic aggregate, 6.7 wt% of first spherical pore-forming agent, 13.3 wt% of carbon fiber, 4.5 wt% of first binder and 0.5% of sodium carboxymethyl cellulose.

In the atomizing core obtained in example 5, the average pore diameter of the first porous ceramic body 11 was 28 μm, the total porosity was 68%, the closed porosity was 0.5%, and the number of fibrous pores was 13% of the spherical pores; the second porous ceramic body 12 has an average pore diameter of 12 μm, a total porosity of 52%, and a closed porosity of 6%.

Example 6

A method of preparing an atomizing core, which differs from example 1 in that: in the first granulated powder, the mass of the first spherical pore-forming agent is not 1.5 times but 4 times the mass of the fibrous pore-forming agent. Namely, the first granulated powder includes: 75 wt% of first ceramic aggregate, 16 wt% of first spherical pore-forming agent, 4 wt% of carbon fiber, 4.5 wt% of first binder and 0.5% of sodium carboxymethylcellulose.

In the atomizing core obtained in example 6, the average pore diameter of the first porous ceramic body 11 was 16 μm, the total porosity was 53%, the closed porosity was 5%, and the number of fibrous pores was 1.2% of the spherical pores; the average pore diameter of the second porous ceramic body 12 is 12 μm, the total porosity is 52%, and the closed porosity is 6%.

Example 7

An atomizing core which differs from example 1 in that: the thickness of the first porous ceramic body 11 was 0.5mm, and the thickness of the second porous ceramic body 12 was 2 mm. That is, in this case, the thickness ratio of the two is 1: 4.

Example 8

An atomizing core which differs from example 1 in that: the thickness of the first porous ceramic body 11 was 2mm, and the thickness of the second porous ceramic body 12 was 0.4 mm. That is, in this case, the thickness ratio of the two is 1: 0.2.

To highlight the advantageous effects of the present application, the following comparative examples are now provided

Comparative example 1

A method of making an atomizing core comprising the steps of:

preparing a dry pressing green body from the second granulated powder in the example 1 by a dry pressing forming method, and sintering at the temperature of 1100 ℃ for 3 hours to obtain a porous ceramic matrix;

cutting the porous ceramic matrix into small blocks, and silk-screening the heating elements on the small blocks to obtain the atomizing core.

In the atomized core obtained in comparative example 1, the porous ceramic matrix is substantially the same as the second porous ceramic body of example 1, and does not have a gradient pore size and porosity distribution and pore morphology. The pores in the porous ceramic matrix prepared in example 1 were spherical pores only.

Comparative example 2

A method of making an atomizing core comprising the steps of:

preparing a dry pressing green body from the first granulated powder in the example 1 by a dry pressing forming method, and sintering at the temperature of 1100 ℃ for 3 hours to obtain a porous ceramic matrix;

Comparative example 2 the atomizing core obtained was substantially the same as the first porous ceramic body in example 1 in that the pores in the porous ceramic matrix included spherical pores and fibrous pores.

Comparative example 3

A method of preparing an atomizing core, which differs from example 1 in that: the first granulated powder contains only a fibrous pore-forming agent. Namely, the first granulated powder includes: 75 wt% of first ceramic aggregate, 20 wt% of carbon fiber, 4.5 wt% of first binder and 0.5 wt% of sodium carboxymethyl cellulose.

In the atomizing core obtained in comparative example 3, the first porous ceramic body 11 had no spherical pores and only fibrous pores, and the first porous ceramic body 11 had an average pore diameter of 35 μm, a total porosity of 65%, and a closed porosity of 0.2%; the average pore diameter of the second porous ceramic body 12 is 12 μm, the total porosity is 52%, and the closed porosity is 6%.

In order to further embody the beneficial effects of the present application, the atomizing cores prepared in the above examples and comparative examples were tested for oil guiding speed, atomizing effect, and crushing strength, and the results are summarized in table 1 below.

TABLE 1

In table 1, the atomization effect is comprehensively judged by two indexes of the amount of the smoke and the oil locking capacity. Wherein, the smoke amount is expressed by percentage, and the test method comprises the following steps: the electronic cigarette resistance tester is used, the suction capacity of each port is set, after the suction time, the smoke generated by the atomizing core is sucked into the glass container, the light transmittance of light passing through the smoke is tested, and the smoke amount (%) is 1-light transmittance (%). The oil locking capacity is expressed by percentage, and the test method is as follows: weighing the atomizing core, soaking the atomizing core in tobacco tar, vacuumizing by using a vacuum pump, sucking gas out of the atomizing core, taking out the atomizing core after the surface of the atomizing core does not bubble any more, and weighing to calculate the weight of saturated oil sucked by the atomizing core; and (3) placing the atomizing core into a container, vacuumizing by using a vacuum pump, closing the vacuum pump after the air pressure is reduced to 0.7 atmospheric pressure, standing the atomizing core for 1 hour under the air pressure, taking out the atomizing core, weighing, and calculating the weight of the residual tobacco tar in the atomizing core, wherein the oil locking capacity (%) (residual oil weight/saturated oil weight).

As can be seen from table 1 and the foregoing description of the pore characteristics of the respective atomizing cores, the atomizing assemblies of comparative examples 1-2 do not have a gradient pore size and porosity distribution, wherein the atomizing core of comparative example 1 has a low oil guiding speed due to the small pore size of the porous ceramic matrix; the atomizing core of the comparative example 2 has the fastest oil guiding speed because the porous ceramic matrix is basically provided with pores with large pore diameters and has high porosity, but the oil locking capacity is the worst, the smoke is wet, and the mechanical property of the atomizing core is deviated; in the atomizing core of comparative example 3, the pores in the first porous ceramic body were only sheet-like pores and were free of spherical pores, and the pores in the second porous ceramic body were spherical pores; although the pores in the first porous ceramic body are larger than those in the second porous ceramic body, the atomization core has a high oil guiding speed, but the mechanical strength is deviated. And the atomizing core that this application embodiment 1-8 provided can have higher oil guide rate and good atomizing effect simultaneously to have higher crushing intensity.

The above-described embodiments are merely illustrative of several exemplary embodiments of the present application, which are described in more detail and detail, but are not to be construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. An atomizing core is characterized by comprising a composite porous ceramic matrix and a heating body arranged on the composite porous ceramic matrix, wherein the composite porous ceramic matrix is provided with a liquid absorbing surface and an atomizing surface which are oppositely arranged, and the heating body is close to the atomizing surface; the composite porous ceramic matrix comprises a first porous ceramic body and a second porous ceramic body connected with the first porous ceramic body, wherein the second porous ceramic body is close to the atomization surface, the average pore diameter of the first porous ceramic body is larger than that of the second porous ceramic body, pores in the first porous ceramic body comprise spherical pores and fibrous pores, and pores in the second porous ceramic body are in a single shape.

2. The atomizing core of claim 1, wherein the pores in the second porous ceramic body comprise spherical pores.

3. The atomizing core of claim 1, wherein the first porous ceramic body has a total porosity greater than or equal to a total porosity of the second porous ceramic body; the first porous ceramic body has a closed porosity that is less than a closed porosity of the second porous ceramic body.

4. The atomizing core of claim 3, wherein the first porous ceramic body has a closed porosity of less than 4%; the second porous ceramic body has a closed porosity of 4% to 10%.

5. The atomizing core of claim 1, wherein the first porous ceramic body has an average pore size of 15 to 40 μ ι η; the second porous ceramic body has an average pore diameter of 8 to 20 μm.

6. The atomizing core of claim 1, wherein the number of fibrous pores in the first porous ceramic body is from 2% to 10% of the number of spherical pores.

7. The atomizing core of claim 1, wherein the first porous ceramic body and the second porous ceramic body have a ratio of thicknesses of 1: (0.3-3).

8. The preparation method of the composite porous ceramic matrix for the atomizing core is characterized by comprising the following steps of:

9. The method of claim 8 wherein the mass of the first spherical pore-forming agent is 1.1 to 3 times the mass of the fibrous pore-forming agent.

10. The preparation method according to claim 8 or 9, wherein the first body comprises the following components in percentage by mass: 65-85% of the first ceramic aggregate, 5-20% of the first spherical pore-forming agent, 5-15% of the fibrous pore-forming agent, 2-10% of the first binder and 0.1-3% of the first dispersant.

11. The preparation method of claim 8, wherein the second body comprises the following components in percentage by mass: 65-85% of second ceramic aggregate, 5-25% of second pore-forming agent, 2-10% of second binder and 0.1-3% of second dispersing agent.

12. The method of claim 8, wherein the first spherical pore former has a particle size of 20 to 60 μ ι η; the particle size of the second pore-forming agent is 12-30 mu m;

the length of the fibrous pore-forming agent is 50-300 μm, and the diameter is 5-30 μm.

13. The method according to claim 8, wherein the fibrous pore-forming agent is at least one selected from the group consisting of carbon fiber, graphite fiber, aramid fiber, silk, and wool; the first spherical pore-forming agent is selected from one or more of inorganic carbon powder, natural organic particles and organic microspheres.

14. The method of claim 8, wherein the second pore former is a spherical pore former.

15. The method of manufacturing of claim 8, wherein the first body is manufactured by a dry forming method of:

pressing the first granulated powder into the first green body.

16. The method of claim 15, wherein the first ceramic slurry further comprises a first dispersant;

the first ceramic slurry is formulated by the following method: firstly, mixing a fibrous pore-forming agent with a first dispersing agent and a first solvent to obtain a dispersion liquid of the fibrous pore-forming agent; and mixing the dispersion liquid of the fibrous pore-forming agent with a first ceramic aggregate, a first spherical pore-forming agent, a first dispersing agent, a first binder and a first solvent to obtain the first ceramic slurry.

17. An electronic atomizing device comprising the atomizing core according to any one of claims 1 to 7 or the atomizing core produced by the production method according to any one of claims 8 to 16.