CN113149697A

CN113149697A - Composition and porous ceramic atomizing core containing continuous glass phase

Info

Publication number: CN113149697A
Application number: CN202110442892.0A
Authority: CN
Inventors: 臧佳栋; 陈湖; 鄢文超
Original assignee: Shenzhen Geekvape Technology Co Ltd
Current assignee: Shenzhen Geekvape Technology Co Ltd
Priority date: 2021-04-23
Filing date: 2021-04-23
Publication date: 2021-07-23

Abstract

A composition and a porous ceramic atomizing core containing a continuous glass phase comprise a powder material, wherein the powder material comprises the following components in percentage by mass: 50-60% of ceramic powder, 15-19% of sintering aid and the balance of pore-forming agent, wherein the sintering aid contains glass powder, the glass powder comprises low-melting-point glass powder, and the softening point of the low-melting-point glass powder is 400-500 ℃. Because the glass powder different from the prior art is selected, the microstructure of the prepared porous ceramic atomizing core has a continuous glass phase, so that the inner surface of a pore channel is smoother, the contact angle is effectively reduced, the oil guiding performance is improved on the premise of not increasing the pore diameter, the oil locking capacity is improved, and oil leakage and core pasting are not easy to occur.

Description

Composition and porous ceramic atomizing core containing continuous glass phase

Technical Field

The invention relates to the field of electronic cigarettes, in particular to a composition and a porous ceramic atomizing core containing a continuous glass phase.

Background

The porous ceramic atomizing core for the existing electronic cigarette is composed of ceramic powder and a glass phase, wherein the ceramic powder plays a role of a supporting structure, and the glass phase is dispersed among the powder to play a role of bonding the ceramic powder. The pores of the porous ceramic come from natural stacking between ceramic powders and addition of pore-forming agents.

The existing porous ceramic atomizing core has the problems of unsmooth oil guide, easy core pasting and the like. In order to improve the oil guiding capacity, the common solution is to increase the pore size of the porous ceramic to improve the oil guiding amount, but the solution has the disadvantage of increasing the risk of oil leakage of the atomizing core.

Disclosure of Invention

According to a first aspect, in one embodiment, there is provided a composition comprising a powder comprising, in mass percent: 50-60% of ceramic powder, 15-19% of sintering aid and the balance of pore-forming agent, wherein the sintering aid contains glass powder, the glass powder comprises low-melting-point glass powder, and the softening point of the low-melting-point glass powder is 400-500 ℃.

According to a second aspect, in an embodiment, there is provided a porous ceramic atomizing core containing the composition of the first aspect.

According to a third aspect, in an embodiment, there is provided a method of making the porous ceramic atomizing core of the second aspect, comprising: the preparation method comprises the steps of mixing the components in the powder according to a ratio to obtain the powder, then mixing the powder with a plasticizer and a dispersing agent to obtain a mixture, carrying out hot-press casting on the mixture to obtain a blank, and then carrying out wax removal and sintering to obtain the porous ceramic atomizing core.

According to a fourth aspect, in an embodiment, there is provided an atomizer comprising the porous ceramic atomizing core of the second aspect.

According to a fifth aspect, in an embodiment, there is provided an electronic cigarette comprising the porous ceramic atomizing core of the second aspect.

According to the composition and the porous ceramic atomizing core containing the continuous glass phase, because the glass powder different from the prior art is selected, the microstructure of the prepared porous ceramic atomizing core has the continuous glass phase, so that the inner surface of a pore channel is smoother, the contact angle is effectively reduced, the oil guiding performance is improved on the premise of not increasing the pore diameter, the oil locking capacity is improved, and oil leakage and core pasting are difficult.

Drawings

FIG. 1 is a schematic view of a microstructure of a conventional porous ceramic;

FIG. 2 is a schematic view of a microstructure of a porous ceramic according to an embodiment;

FIG. 3 is a schematic diagram showing the change in contact angle before and after modification;

FIG. 4 is a scanning electron micrograph of a porous ceramic atomizing core according to an embodiment;

FIG. 5 is a schematic structural diagram of an embodiment of a porous ceramic atomizing core;

FIG. 6 is a schematic structural diagram of another embodiment of a porous ceramic atomizing core.

Detailed Description

The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.

Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).

Herein, the term "contact angle" refers to the angle from the solid-liquid interface to the gas-liquid interface through the interior of the liquid at the three-phase solid, liquid and gas intersection.

As shown in fig. 1, the microstructure of the existing porous ceramic is schematically shown, and the existing porous ceramic atomizing core for the electronic cigarette is composed of ceramic powder and a glass phase, wherein the ceramic powder plays a role of a supporting structure, and the glass phase is dispersed among the powder to play a role of bonding the ceramic powder. The pores of the porous ceramic come from natural stacking between ceramic powders and addition of pore-forming agents.

Since the ceramic powder is mainly made of metal oxide particles by grinding and crushing, the surface roughness of the powder is very high. The higher surface roughness can increase the contact angle between the tobacco tar and the ceramic oil guide material, thereby reducing the wettability of the porous ceramic to the tobacco tar. Therefore, the existing porous ceramic atomizing core often has the defects of unsmooth oil guide and easy core pasting, and particularly, the roughness of the surface of the powder is high, so that the unsmooth oil guide of the porous ceramic atomizing core is caused, the smoke oil near the heating wire of the porous ceramic atomizing core is less, and the heating wire is dried and burnt, and the core pasting phenomenon is caused. In order to improve the oil guiding capacity, the common solution is to increase the pore size of the porous ceramic to improve the oil guiding amount, but the solution has the disadvantage of increasing the risk of oil leakage of the atomizing core.

According to a first aspect, in one embodiment, there is provided a composition comprising a powder comprising, in mass percent: 50-60% of ceramic powder, 15-19% of sintering aid and the balance of pore-forming agent, wherein the sintering aid contains glass powder, the glass powder comprises low-melting-point glass powder, and the softening point of the low-melting-point glass powder is 400-500 ℃. The softening point parameters of the glass frits are generally provided by the manufacturers. The ceramic powder has the function of forming a structural framework, the sintering aid has the function of bonding the powder and reducing the sintering temperature, and the pore-forming agent has the function of vaporizing to form pores.

In one embodiment, the low melting point glass frit includes, but is not limited to, at least one of borosilicate low melting point glass frit, lead-free low melting point glass frit. The main elements of the lead-free low-melting-point glass powder comprise Al, Si, Bi, K and O.

In one embodiment, the low-melting-point glass powder has an average particle size of 5 to 15 μm.

In one embodiment, the ceramic powder includes, but is not limited to, at least one of diatomaceous earth, cordierite, alumina, silica, silicon carbide, silicon nitride, silica sand, corundum sand, glass sand, kaolin, clay, spray granulated powder.

In one embodiment, the ceramic powder is fused silica.

In one embodiment, the ceramic powder has a particle size of 10 to 70 μm.

In one embodiment, the spray-granulated powder is obtained by spray granulation of a spray stock solution, and the spray granulation stock solution contains fused silica.

In one embodiment, the mass ratio of the fused silica in the spray granulation stock solution is 40 to 50%.

In one embodiment, the spray granulation stock solution further contains at least one of polyvinyl alcohol and boric acid.

In one embodiment, the temperature of the spray inlet is 250-300 ℃ and the temperature of the spray outlet is 110-150 ℃.

In one embodiment, the pore former includes, but is not limited to, at least one of polystyrene microspheres, Polymethyl Methacrylate Microspheres (PMMA), polyurethane microspheres, polypropylene microspheres, polyvinyl chloride microspheres, carbon powder, carbonate, nitrate, ammonium salt, wood dust, flour, corn flour, starch, and bean flour.

In one embodiment, the pore-forming agent has a particle size of 5 to 500 μm, preferably 10 to 50 μm, and more preferably 10 to 20 μm.

In one embodiment, the composition further comprises a plasticizer.

In one embodiment, the mass of the plasticizer is 15-30%, 20-28% or 17-23% of the mass of the powder.

In one embodiment, the plasticizer includes, but is not limited to, at least one of paraffin wax, beeswax, Polyethylene (PE), polyethylene wax (PE wax), polypropylene (PP).

In one embodiment, the plasticizer is selected from at least one of paraffin wax and beeswax.

In one embodiment, the plasticizer is selected from the group consisting of paraffin: beeswax 10: (0.5 to 1.5).

In one embodiment, the composition further comprises a dispersant.

In one embodiment, the mass of the dispersant is 0.5-5% of the mass of the powder, including but not limited to 0.5%, 1%, 2%, 3%, 4%, 5%.

In one embodiment, the dispersant includes, but is not limited to, at least one of oleic acid, stearic acid.

In one embodiment, the composition is a composition for preparing a porous ceramic atomizing core, the sintering aid selected by the invention can form a continuous glass phase, the surface of the ceramic powder is covered by the glass phase, and the continuous glass phase effectively reduces a contact angle between the tobacco tar and the ceramic oil guide material, so that the oil guide rate is increased on the premise of not increasing the aperture, and the oil leakage risk caused by the increase of the aperture in the prior art is effectively reduced.

In one embodiment, the porous ceramic atomizing core is prepared from the composition of the first aspect. The composition of the first aspect is used as a raw material to prepare the porous ceramic atomizing core through a certain process.

In an embodiment, the porous ceramic atomizing core is a porous ceramic atomizing core for preparing an electronic cigarette.

In one embodiment, the pore diameter of the porous ceramic atomizing core is 10-20 μm.

In one embodiment, the porosity of the porous ceramic atomizing core is 48-55%.

In one embodiment, the time for completely soaking the porous ceramic atomizing core in the tobacco tar with the liquid level height of 1mm is 30-80 s.

In one embodiment, the porous ceramic atomizing core can be a porous ceramic atomizing core for an electronic cigarette.

In one embodiment, the porous ceramic atomizing core is made from the composition of the first aspect.

In one embodiment, the porous ceramic atomizing core contains a continuous glass phase.

The glass phase, also known as supercooled liquid phase, is the portion of the ceramic microstructure that is composed of amorphous solids. It exists between crystal grains and plays a role in adhesion. The sintering aid (glass powder) in the ceramic body forms a melt (liquid state) at high temperature, and atoms, ions or molecules are "frozen" into an amorphous solid, i.e., a glass phase, during cooling.

According to a third aspect, in an embodiment, there is provided a method of making the porous ceramic atomizing core of the second aspect, comprising: the preparation method comprises the steps of mixing the components in the powder according to a ratio to obtain the powder, then mixing the powder with a plasticizer to obtain a mixture, carrying out hot-press casting on the mixture to obtain a blank, and then carrying out dewaxing and sintering to obtain the porous ceramic atomizing core.

In one embodiment, the temperature of the hot-press casting is 60-70 ℃ and the pressure is 0.7-1 MPa.

In one embodiment, the specific method of wax removal is as follows: and heating the blank obtained by hot die casting to a first temperature at the speed of 1 ℃/min, and then heating to a second temperature at the speed of 0.5 ℃/min to obtain the paraffin removal material.

In one embodiment, the first temperature is 200-250 ℃.

In one embodiment, the second temperature is 400-450 ℃.

In one embodiment, the specific method of sintering is as follows: and heating to a third temperature at the speed of 1 ℃/min, and preserving heat for 0.5h to obtain the porous ceramic atomizing core.

In one embodiment, the third temperature is 600-650 ℃.

Example 1

This example provides a method of making an atomizing core.

In the embodiment, the powder material comprises the following components in percentage by mass: 60% fused silica powder (average particle size of 20 μm), 17% glass powder (average particle size of 10 μm), and 23% pore-forming agent (PMMA, average particle size of 20 μm). The glass powder is borosilicate glass powder with a softening point of about 500 ℃ (the initial batch for melting the glass powder contains 22-25% by mass of boron oxide, 2-5% by mass of sodium oxide and the balance of silicon dioxide). Adding the raw materials into a drum mixer for mixing to obtain powder, adding a plasticizer and a dispersant into the powder, wherein the plasticizer comprises the following components by mass: paraffin wax: beeswax 10: 1, the dispersing agent is oleic acid, the adding mass of the plasticizing agent is 25% of the mass of the powder, the adding mass of the oleic acid is 1% of the mass of the powder, the mixture is stirred and mixed for 2 hours at the temperature of 60-70 ℃, and the mixture is transferred into a hot die casting machine and is subjected to hot die casting at the temperature of 70 ℃ and under the pressure of 0.7-1 MPa to obtain a ceramic blank. Then, de-waxing is carried out, samples are all buried in the alumina-based de-waxing powder, and the de-waxing method comprises the following specific steps: heating the blank obtained by hot die casting to 200-250 ℃ at the speed of 1 ℃/min, and then heating to 400-450 ℃ at the speed of 0.5 ℃/min to obtain a paraffin removal material; then sintering the mixture for 30min at 650 ℃ to prepare the porous ceramic atomizing core.

In the preparation process, the paraffin is completely discharged, the pore-forming agent is completely vaporized and volatilized, and only the ceramic powder and the glass powder are finally retained in the porous ceramic atomizing core product.

Example 2

This example was conducted with reference to example 1 except that the glass frit in example 1 was replaced with a lead-free low-melting glass frit having a softening point of about 450 degrees (average particle diameter of 8 μm).

Example 3

This example was carried out with reference to example 1, except that the fused silica powder in example 1 was replaced with the powder after the spray granulation treatment. During spray granulation, the mass content of fused silica in the spray stock solution is 45%, the mass content of PVA (polyvinyl alcohol) in the spray stock solution is 0.5%, the mass content of boric acid is 0.5%, and the balance is water. The inlet temperature of the spray was 300 ℃ and the outlet temperature was 150 ℃.

Comparative example 1

This comparative example was conducted with reference to example 1 except that the glass frit in example 1 was replaced with a boron oxide glass frit (amorphous boron oxide, average particle size of 6 μm) having a softening point of about 325 ℃.

Comparative example 2

This comparative example was conducted with reference to example 1 except that the glass frit in example 1 was replaced with bismuth oxide glass frit having a softening point of about 530 ℃ (bismuth oxide content of 70 to 80% by mass in the initial batch used for melting the glass frit, balance being boron oxide and zinc oxide components), and the bismuth oxide glass frit had an average particle diameter of 12 μm).

Comparative example 4

This comparative example was conducted with reference to example 1 except that the content of the glass frit in example 1 was adjusted to 14%. The content of the ceramic powder is correspondingly improved to 63 percent.

Comparative example 5

This comparative example was conducted with reference to example 1 except that the content of the glass frit in example 1 was adjusted to 20%. The content of the ceramic powder is correspondingly reduced to 57 percent.

Test experiments

The "pore size" in table 1, the "average pore size of ceramic atomizing core" in table 2 was tested as follows: the aperture in the electron micrograph was analyzed with image recognition software.

The test method for "porosity" in Table 1 is referred to GB/T1966-1996 porous ceramic apparent porosity, volume weight test method.

The detection method of the oil guiding time in table 1 is as follows: the ceramic sample was placed in a container containing tobacco tar at a level of 1mm and the time to complete infiltration was observed. The test method of "average oil drainage rate of 10 μm average pore size sample" in table 2 is the same as the test method of "oil drainage time" in table 1.

The glass phase distribution in Table 1 was observed in an electron micrograph.

The contact angle test methods in table 2 are carried out with reference to ISO 15989.

The oil leakage rate in table 2 was tested as follows: the samples were stored at low pressure under the following conditions: -30kPa, time 6 h; then, an oil leakage rate test was performed, in which 15 samples were tested in total, the main components of the test tobacco oil being 50% propylene glycol and 50% vegetable glycerin (glycerol) by volume, and the oil leakage rate (number of oil leakage samples/total number of test samples) was 100%.

TABLE 1

Group of	Pore size (micron)	Porosity of the material	Oil guiding time	Distribution of glass phase
					Example 1	10-20	50-53％	30-70s	(Continuous)
Example 2	10-20	50-53％	30-70s	(Continuous)
					Example 3	8-15	49-52％	50-80s	(Continuous)
Comparative example 1	10-20	50-53％	100-120s	Has a certain continuity and is not uniform
					Comparative example 2	10-20	50-53％	100-120s	Has a certain continuity and is not uniform
Comparative example 4	15-20	58％	20-50s	Discrete discontinuity of dispersion
					Comparative example 5	5-10	40％	200-250s	Continuous, but too low porosity to be used

The following table is a statistical table of performance indexes of the commercially available porous ceramic atomizing core and the porous ceramic atomizing core prepared in example 1 of the present invention.

TABLE 2

As can be seen from Table 2, the porous ceramic atomizing core prepared in example 1 of the present invention has the advantages of better tobacco tar wettability, stronger oil guiding capability, smaller average pore size, and better oil locking property.

In one embodiment, the porous ceramic atomizing core for effectively improving the tobacco tar wettability of the porous ceramic is prepared. Fig. 2 is a schematic view showing the microstructure of the porous ceramic of the present invention, in which the surface of the ceramic powder is completely covered by the glass phase and the glass phase forms a continuous whole. Because the glass phase can be liquefied and forms a smooth surface in the sintering process, the scheme effectively reduces the roughness of the inner surface of the pore, and further greatly improves the wettability of the porous ceramic to the tobacco tar.

In one embodiment, the porous ceramic atomizing core provided by the invention improves the transfer rate of tobacco tar in the porous ceramic atomizing core compared with the existing porous ceramic atomizing core.

In one embodiment, compared with the existing porous ceramic atomizing core, the porous ceramic atomizing core provided by the invention has the advantages that the average pore diameter under the same atomizing effect is reduced, oil guiding and oil locking are better balanced, and the oil leakage risk is reduced.

In one embodiment, FIG. 2 is a schematic microstructure of a porous ceramic atomizing core of the present invention, wherein the surface of the ceramic powder is completely covered by a continuous glass phase, thereby forming a smooth inner surface within the pores.

In one embodiment, fig. 3 is a schematic diagram of the effect of the porous ceramic atomizing core before and after modification on the contact angle between the soot and the ceramic surface, and it can be found that the contact angle of the smooth surface is smaller, and therefore the wetting property of the soot is better.

In one embodiment, FIG. 4 is a scanning electron micrograph of a practical sample of the porous ceramic atomizing core of example 1 of the present invention showing a continuous distribution of glassy phase and pores ranging in size from 10 to 20 microns. The type of a scanning electron microscope: JSM-IT 500A; the manufacturer: JEOL (Japanese electronic Co., Ltd.).

In one embodiment, the atomizing core made of the composition of the present invention has a square structure as shown in fig. 5, the atomizing core has a square structure, the heating wire is located at the bottom of the atomizing core, the tobacco tar is fed from the square groove at the upper part and permeates to the bottom, the heating wire is connected to a power supply device such as a battery, and the tobacco tar in the micropores of the atomizing core is atomized by the heat generated by the heating wire.

In one embodiment, the atomizing core made of the composition of the present invention is shown in fig. 6, the atomizing core is a cylindrical structure, the middle is a through hole as an atomizing air passage, the heating wire is located on the inner wall of the central hole, the tobacco tar permeates into the inner wall from the outer wall, the heating wire is connected to a power supply device such as a battery, and the tobacco tar in the micropores of the atomizing core can be atomized by the heat generated by the heating wire.

The specific atomizing core structure is not limited, fig. 5 and 6 are only exemplary illustrations, and the atomizing core can be made into other structures.

The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention pertains, several simple deductions, modifications or substitutions may be made according to the idea of the invention.

Claims

1. The composition is characterized by comprising powder, wherein the powder comprises the following components in percentage by mass: 50-60% of ceramic powder, 15-19% of sintering aid and the balance of pore-forming agent, wherein the sintering aid contains glass powder, the glass powder comprises low-melting-point glass powder, and the softening point of the low-melting-point glass powder is 400-500 ℃.

2. The composition of claim 1, wherein the low-melting glass frit comprises at least one of a borosilicate low-melting glass frit, a lead-free low-melting glass frit;

and/or the average particle size of the low-melting-point glass powder is 5-15 mu m.

3. The composition of claim 1, wherein the ceramic powder comprises at least one of diatomaceous earth, cordierite, alumina, silica, silicon carbide, silicon nitride, quartz sand, corundum sand, glass sand, kaolin, clay, spray-granulated powder;

and/or the ceramic powder is fused quartz;

and/or the particle size of the ceramic powder is 10-70 μm;

and/or the spray granulation powder is obtained by spray granulation of spray stock solution, wherein the spray granulation stock solution contains fused quartz;

and/or the mass ratio of the fused quartz in the spray granulation stock solution is 40-50%;

and/or the spray granulation stock solution also contains at least one of polyvinyl alcohol and boric acid;

and/or the temperature of the spraying inlet is 250-300 ℃, and the temperature of the spraying outlet is 110-150 ℃.

4. The composition of claim 1, wherein the pore-forming agent comprises at least one of polystyrene microspheres, polymethylmethacrylate microspheres (PMMA), polyurethane microspheres, polypropylene microspheres, polyvinyl chloride microspheres, carbon powder, carbonate, nitrate, ammonium salt, wood chips, flour, corn flour, starch, and bean flour;

and/or the particle size of the pore-forming agent is 5-500 μm, preferably 10-50 μm, and more preferably 10-20 μm.

5. The composition of claim 1, further comprising a plasticizer comprising at least one of paraffin wax, beeswax, polyethylene wax, polypropylene, stearic acid, oleic acid;

and/or the mass of the plasticizer is 15-30% of the mass of the powder;

and/or the plasticizer is selected from at least one of paraffin wax and beeswax;

and/or, by mass, the plasticizer comprises paraffin: beeswax 10: (0.5 to 1.5);

and/or, the composition further comprises a dispersant;

and/or the mass of the dispersing agent is 0.5-5% of the mass of the powder;

and/or, the dispersant includes, but is not limited to, at least one of oleic acid, stearic acid;

and/or the composition is a composition for preparing a porous ceramic atomizing core.

6. A porous ceramic atomizing core comprising the composition according to any one of claims 1 to 5.

7. The porous ceramic atomizing core according to claim 6, wherein the pore size of the porous ceramic atomizing core is 10 to 20 μm;

and/or the porosity of the porous ceramic atomizing core is 48-55%;

and/or the time for completely soaking the oil absorption rate of the porous ceramic atomization core in the tobacco tar with the liquid level height of 1mm is 30-80 s;

and/or the porous ceramic atomizing core is used for the electronic cigarette;

and/or, the porous ceramic atomizing core is prepared from the composition of any one of claims 1 to 5;

and/or, the porous ceramic atomizing core contains a continuous glass phase.

8. The method of making a porous ceramic atomizing core according to claim 6 or 7, comprising: the preparation method comprises the steps of mixing the components in the powder according to a ratio to obtain the powder, then mixing the powder with a plasticizer and a dispersing agent to obtain a mixture, carrying out hot-press casting on the mixture to obtain a blank, and then carrying out wax removal and sintering to obtain the porous ceramic atomizing core.

9. An atomizer, characterized in that it comprises a porous ceramic atomizing core according to claim 6 or 7.

10. An electronic cigarette, characterized in that it comprises a porous ceramic atomizing core according to claim 6 or 7.