阅读说明：本技术 一种电子烟用多孔陶瓷雾化芯及其制备方法和应用 (Porous ceramic atomizing core for electronic cigarette and preparation method and application thereof ) 是由 刘裔云 于 2021-09-06 设计创作，主要内容包括：本发明涉及电子烟技术领域,公开了一种电子烟用多孔陶瓷雾化芯及其制备方法和应用。本发明利用水解沉淀制备莫来石前驱体凝胶,并且掺入碳酸钙、硝酸钙、硝酸镁、硝酸铵等无机盐,烘干得到混合粉体,溶于蜡质体系中,通过热压铸成型,排蜡烧结得到最终多孔陶瓷雾化芯,产品孔隙率范围在30-60％,强度≥20MPa,吸油速率1.2-2.5mg/s,热导率1.8-2.5W/(m·k),相比较常规的单一陶瓷粉雾化芯,在强度、吸油速率以及热导率方面均有很明显的提升,可应用于电子烟的制备领域。(The invention relates to the technical field of electronic cigarettes, and discloses a porous ceramic atomizing core for an electronic cigarette, and a preparation method and application thereof. The method prepares mullite precursor gel by hydrolysis precipitation, and adds inorganic salts such as calcium carbonate, calcium nitrate, magnesium nitrate, ammonium nitrate and the like, dries to obtain mixed powder, dissolves the mixed powder in a waxy system, and obtains a final porous ceramic atomizing core by hot-press casting molding, dewaxing and sintering, wherein the porosity of the product is in the range of 30-60%, the strength is not less than 20MPa, the oil absorption rate is 1.2-2.5mg/s, and the thermal conductivity is 1.8-2.5W/(m.k).)

1. A porous ceramic atomizing core for electronic cigarettes is characterized by being prepared by mixing tetraethoxysilane, aluminum chloride, mullite, a pH regulator, inorganic salt, wax and a modifier, then carrying out green pressing, and carrying out wax removal and sintering.

2. The atomizing core according to claim 1, characterized in that a precursor gel is formed from ethyl orthosilicate, aluminum chloride, mullite, ammonia water.

3. The atomizing core of claim 1, wherein the modifying agent is stearic acid.

4. The atomizing core according to claim 1, wherein the inorganic salt is selected from one or more of calcium carbonate, calcium nitrate, magnesium nitrate and ammonium nitrate.

5. The atomizing core of claim 1, wherein the wax is paraffin wax.

6. Use of an atomizing core according to any one of claims 1 to 5 in the manufacture of an electronic cigarette.

7. A method of making an atomizing core of claim 1, comprising:

step 1, dissolving tetraethoxysilane, aluminum chloride and mullite in a solvent, adding a pH value regulator to regulate the pH value to perform a precipitation reaction, and generating precursor gel;

and 2, mixing the precursor gel and inorganic salt, dissolving the mixture in wax and a modifier, mixing, and then green-pressing, dewaxing and sintering to obtain the atomized core.

8. The method according to claim 7, wherein the solvent is water or ethanol.

9. The preparation method according to claim 7, wherein the precipitation reaction is carried out by adding the pH regulator to adjust the pH value, and the precipitation reaction is carried out by adding the pH regulator to the system pH value of 2-8.

10. The method of claim 7, wherein the inorganic salt is added in an amount of 30-70% by weight based on the total weight of the precursor gel.

Technical Field

The application relates to the technical field of electronic cigarettes, in particular to a porous ceramic atomizing core for electronic cigarettes and a preparation method and application thereof.

Background

The electronic smoking set is an electronic device which transfers nicotine to a respiratory system by electrically heating and atomizing electronic atomized liquid. The atomizing core in the electronic smoking set absorbs the electronic atomized liquid, and the heating wire heats the atomizing core, so that the absorbed electronic atomized liquid is atomized to form aerosol which is sucked by a user.

Most of the ceramic atomization cores of the existing electronic cigarettes are made of single ceramic powder, then glass powder and a pore-forming agent are mixed uniformly, the mixture is dissolved in paraffin and a stearic acid modifier, a product green body is prepared by molding, and then the product is obtained by dewaxing and sintering. However, the existing ceramic atomizing core has single base material and uneven microstructure, which causes uneven heat conduction effect and atomizing effect, thereby causing poor smoking taste and risks of oil leakage and core pasting.

Disclosure of Invention

In view of this, the invention aims to provide a porous ceramic atomizing core for an electronic cigarette and a preparation method thereof, so that the prepared atomizing core has higher thermal conductivity;

the invention also aims to provide the porous ceramic atomizing core for the electronic cigarette and the preparation method thereof, so that the prepared atomizing core has higher strength;

the invention also aims to provide the porous ceramic atomizing core for the electronic cigarette and the preparation method thereof, so that the prepared atomizing core has higher oil absorption rate;

another object of the present invention is to provide the use of the atomizing core prepared as above in the preparation of electronic cigarettes.

In order to solve the technical problems or at least partially solve the technical problems, the invention provides a porous ceramic atomizing core for an electronic cigarette, which is prepared by mixing tetraethoxysilane, aluminum chloride, mullite, a pH value regulator, inorganic salt, wax and a modifier, then carrying out green pressing, and carrying out wax removal and sintering. In the specific embodiment of the invention, a precursor gel is formed by tetraethoxysilane, aluminum chloride, mullite and ammonia water; preferably, the pH adjuster is ammonia water. The pH value of the system is adjusted to be 2-8 by a pH value regulator to quickly generate hydrolysis precipitation reaction to generate precursor gel; in the present invention, mullite has the meaning and description generally in the art and is SiO₂/Al₂O₃The mineral of element system, the mullite alumina content of the invention is preferably 68% + -5%, belongs to the products sold in the field, and has two obtaining modes of natural sintering and artificial sintering.

The invention firstly prepares the precursor gel to ensure that the mixed powder is more uniform, and the inorganic salt can be dopedThe pore-forming agent can also be used as a sintering aid, on one hand, the high-temperature decomposition generates gas to form a pore channel to serve as the pore-forming agent, and on the other hand, the oxide after the decomposition can be mixed with SiO₂/Al₂O₃The low-temperature liquid phase is formed, the microstructure of the prepared porous ceramic is more uniform, the sintering temperature is lower, the energy is saved, the cost is reduced, and the mullite phase (SiO)₂/Al₂O₃) Compared with silicon oxide, the silicon oxide has the advantages of higher thermal conductivity and strength, higher thermal conductivity, difficulty in core pasting, higher strength and improvement of assembly reliability.

The modifier and wax may be selected from modifiers and waxes conventional in the art, such as stearic acid and paraffin wax, and the precursor gel incorporating the inorganic salt is dissolved in the wax and modifier at a solids content of 50-80%. In a specific embodiment of the present invention, the inorganic salt is one or more selected from calcium carbonate, calcium nitrate, magnesium nitrate, and ammonium nitrate, and the mixing ratio is 30-70% of the total weight of the precursor gel (dried powder) and the inorganic salt.

Compared with the conventional single ceramic powder atomizing core, the atomizing core can improve the compressive strength at 15-22MPa, the heat conductivity at 1.4-2.1W/(m.k), the oil absorption rate at 0.4-1.7mg/s, the product porosity at 30-60%, the strength at more than or equal to 20MPa and the oil absorption rate at 1.2-2.5 mg/s. Based on the excellent technical effects, the invention provides the application of the atomization core in the preparation of the electronic cigarette.

Meanwhile, the invention also provides a preparation method of the atomization core, which comprises the following steps:

step 1, dissolving tetraethoxysilane, aluminum chloride and mullite in a solvent, adding a pH regulator to regulate the pH value to perform a precipitation reaction, and generating precursor gel;

and 2, mixing the precursor gel and inorganic salt, dissolving the mixture in wax and a modifier, mixing, and then green-pressing, dewaxing and sintering to obtain the atomized core.

In a specific embodiment of the invention, the weight ratio of the ethyl orthosilicate (CP), the crystalline aluminum chloride (AR) and the mullite in the step 1 is 66:17:17-70:15:15, and the weight ratio of the crystalline aluminum chloride (AR) and the mullite is equal; in a particular embodiment of the invention, the weight ratio between tetraethylorthosilicate, crystalline aluminium chloride and mullite is 66:17:17 or 68: 16: 16; the ethyl orthosilicate and the crystalline aluminum chloride act as hydrolysis precipitates to obtain mullite precursor gel; the solvent is water and ethanol (CP), the solvent preferably accounts for 30% of the total proportion (the total weight of the ethyl orthosilicate, the aluminum chloride, the mullite and the solvent), and the volume ratio of the deionized water to the ethanol is preferably 3: 7.

In the specific embodiment of the invention, the precursor gel is prepared by adding a pH value regulator such as ammonia water and the like to regulate the pH value range to 2-8, preferably, the pH value is 3, and the precursor gel is obtained by rapid precipitation reaction, wherein the solution temperature is 60-80 ℃, the solution temperature is preferably 70 ℃, and the reaction time is 5-20min, preferably 10 min;

in a specific embodiment of the present invention, the amount of the inorganic salt such as calcium carbonate, calcium nitrate, magnesium nitrate, ammonium nitrate (pore-forming agent and sintering aid) is 30 to 70%, for example, 30%, 50% or 70% of the total weight of the precursor gel (dried powder) and the inorganic salt; when a plurality of inorganic salts are used, the proportion of the inorganic salts is not limited, and the total weight is consistent.

In the specific embodiment of the invention, the mixing temperature is more than 70 ℃, the mixing time is more than 3h, and the forming temperature of the prepared green body is 75 +/-10 ℃;

in the embodiment of the invention, the dewaxing and sintering can be performed in the same furnace, or the dewaxing and sintering can be performed in a high temperature furnace, wherein the sintering temperature is 850-. As a reference wax removal mode, the invention provides the following scheme:

heating rate of 1-2 deg.C/min from room temperature to 300 deg.C; 300 ℃ and 600 ℃, and the heating rate is 0.5-1 ℃/min;

as a reference sintering method, the present invention provides the following scheme:

the temperature is raised to 600 ℃ at the rate of 5-10 ℃/min; the temperature is raised to the highest temperature from 600 ℃, the heating rate is 3-5 ℃/min, and the temperature is kept for 0.5-3h at the highest temperature.

According to the technical scheme, the mullite precursor gel is prepared by hydrolysis precipitation, inorganic salts such as calcium carbonate, calcium nitrate, magnesium nitrate, ammonium nitrate and the like are added, mixed powder is obtained by drying, the mixed powder is dissolved in a waxy system, hot-press casting molding and de-waxing sintering are carried out, the final porous ceramic atomizing core is obtained, the porosity of the product is in the range of 30-60%, the strength is not less than 20MPa, the oil absorption rate is 1.2-2.5mg/s, and the thermal conductivity is 1.8-2.5W/(m.k).

Detailed Description

The invention discloses a porous ceramic atomizing core for electronic cigarettes and a preparation method and application thereof, and a person skilled in the art can realize the atomization by properly improving process parameters by referring to the content. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the processes, applications and products of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the processes, applications and products described herein may be made and used without departing from the spirit and scope of the invention. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It is noted that, in this document, relational terms such as "first" and "second", "step 1" and "step 2", and "(1)" and "(2)" are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

In the comparison experiment of the invention, except the due differences of each group, the experiment environment, the process parameters, the raw material source batches and the like which are not particularly described are kept consistent, and the comparability of the experiment result is ensured.

The preparation process of the atomization core refers to the following steps:

1. tetraethoxysilane (CP) and crystalline aluminum chloride (AR) solution according to mullite Al₂O₃/SiO₂67/33-70/30, mixing and completely dissolving in distilled water and ethanol (CP) solution;

2. adding ammonia water (AR) to adjust the pH range to 2-8, and quickly performing hydrolysis precipitation reaction to obtain precursor gel; the solution temperature is 60-80 ℃, and the reaction time is 5-20 min;

3. washing and drying the precursor gel, adding one or more inorganic salts selected from calcium carbonate, calcium nitrate, magnesium nitrate, ammonium nitrate (pore-forming agent and sintering aid) and the like, wherein the weight ratio of the inorganic salts is 30-70%, and uniformly mixing by a mixer;

4. dissolving the mixed powder in paraffin and stearic acid, wherein the solid content is 50-80%, so as to form a uniform mixed material, the mixing temperature is higher than 70 ℃, the mixing time is longer than 3h, and the mixed material is subjected to hot-press casting to prepare a product green body, wherein the forming temperature is 75 +/-10 ℃;

5. and (3) carrying out low-temperature dewaxing on the product green body to obtain a dewaxed product, wherein the specific temperature curve is as follows: the temperature is between room temperature and 300 ℃, and the temperature is 1-2 ℃/min; 300 ℃ and 600 ℃, 0.5-1 ℃/min; the dewaxing product can be obtained by high-temperature sintering, the sintering temperature is 850-1150 ℃, and the specific temperature curve is as follows: the temperature is between room temperature and 600 ℃, and the temperature is between 5 and 10 ℃/min; the temperature is from 600 ℃ to the highest temperature, 3-5 ℃/min, and the temperature is kept for 0.5-3 h; the dewaxing and sintering can be carried out in the same furnace, or the dewaxing can be carried out at low temperature first, and then the sintering is carried out in a high-temperature furnace;

6. the porosity of the product is in the range of 30-60%, the strength is not less than 20MPa, the oil absorption rate is 1.2-2.5mg/s, and the thermal conductivity is 1.8-2.5W/(m.k).

Example 1: the invention is compared with the conventional single ceramic powder

The process and technical effects of the invention and the comparative example are compared in the following table 1, in which each example parameter can be combined with or replaced by other example parameters;

TABLE 1

As can be seen from Table 1, compared with the conventional single ceramic powder atomizing core, the atomizing core of the invention can improve the compressive strength at 15-22MPa, the thermal conductivity at 1.4-2.1W/(m.k), the oil absorption rate at 0.4-1.7mg/s, the product porosity at 30-60%, the strength at more than or equal to 20MPa and the oil absorption rate at 1.2-2.5 mg/s. Therefore, the atomization core can effectively improve the heat conduction effect and the non-uniform atomization effect, so that the electronic cigarette has poor smoking taste and has the phenomena of oil leakage and core pasting risks, and the assembly reliability is improved.

The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.