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CN-121990577-A - Silica microsphere with core-shell structure and hierarchical pores, and preparation method and application thereof

CN121990577ACN 121990577 ACN121990577 ACN 121990577ACN-121990577-A

Abstract

The invention relates to the technical field of tobacco materials, in particular to a silicon dioxide microsphere with a core-shell structure and a hierarchical pore, and a preparation method and application thereof. The preparation method of the silica microsphere with the core-shell structure and the multistage holes comprises the following steps of 1) mixing a polyvinyl alcohol aqueous solution with nano silica particles, stirring the mixture into floccules, 2) preparing the floccules obtained in the step 1) into spheres, namely, the core structure of the silica microsphere, 3) wrapping the mixture of the mesoporous silica particles and the pore-forming agent which are mixed in advance on the surface of the core structure prepared in the step 2) to serve as the shell structure of the silica microsphere, so as to obtain the silica microsphere with the core-shell structure, and 4) performing heat treatment on the core-shell structure of the silica microsphere to form multistage holes, namely, the silica microsphere with the core-shell structure and the multistage holes. The silica microsphere with the core-shell structure and the multistage holes has multistage holes with different sizes, so that the fragrance carrying capacity can be improved, and the slow release performance can be improved.

Inventors

  • WU ZHAO
  • ZHANG LEILEI
  • YU QICHANG
  • XU LAN
  • Xi an
  • WU BINGYU
  • GAO JIANHONG

Assignees

  • 上海烟草集团有限责任公司
  • 上海白玉兰烟草材料有限公司

Dates

Publication Date
20260508
Application Date
20241108

Claims (10)

  1. 1. A method for preparing silica microspheres with a core-shell structure and hierarchical pores, which is characterized by comprising the following steps: 1) Mixing polyvinyl alcohol aqueous solution with nano silicon dioxide particles, and stirring to form floccules; 2) Preparing the floccule obtained in the step 1) into spheres, namely a nuclear structure of the silicon dioxide microspheres; 3) Wrapping the mixture of the pre-mixed mesoporous silica particles and the pore-forming agent on the surface of the nuclear structure prepared in the step 2) to be used as a shell structure of the silica microsphere, so as to obtain the silica microsphere containing the nuclear shell structure; 4) And (3) performing heat treatment to form multistage holes on the core-shell structure of the silica microsphere, thereby obtaining the silica microsphere with the core-shell structure and the multistage holes.
  2. 2. The method of claim 1, wherein in step 1) any one or more of the following conditions are included: 12 The stirring speed is 400-800 rpm; 13 The stirring time is 10-20 hours; 14 The mass concentration of the polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 8% -15%; 15 Polyvinyl alcohol is selected from one or more of polyvinyl alcohol 1788 type, polyvinyl alcohol 1799 type, polyvinyl alcohol 2488 type and polyvinyl alcohol 2699 type; 16 The mixing mass ratio of the nano silicon dioxide particles to the polyvinyl alcohol aqueous solution is 1:1.5-2.
  3. 3. The method of claim 1, wherein in step 2) any one or more of the following conditions are included: 21 The particle size of the sphere is 0.3-0.5 mm; 22 Before preparing the spheres, extruding and granulating the floccules to form strip-shaped particles; 23 The equipment for preparing the ball body is a shot blasting machine, and the rotating speed of the shot blasting machine is 200-400 revolutions per minute.
  4. 4. The method of claim 1, wherein in step 3) any one or more of the following conditions are included: 31 The mixing mass ratio of the mesoporous silica to the pore-foaming agent is 1:0.1-10; 32 The model of the mesoporous silica particles is one or more selected from SBA-15, SBA-16, SBA-8 and SBA-11; 33 The pore-forming agent is one or more of polyvinyl alcohol, polypropylene or polystyrene; 34 Wrapping the mixture of the pre-mixed mesoporous silica particles and the pore-forming agent on the surface of the nuclear structure prepared in the step 2) in a shot blasting machine, wherein the rotating speed of the shot blasting machine is preferably 100-200 revolutions per minute.
  5. 5. The method for preparing the microsphere according to claim 1, wherein in the step 3), the particle size of the core-shell structure-containing silica microsphere is verified, and preferably, the particle size of the core-shell structure-containing silica microsphere is 1-2 mm.
  6. 6. The method according to claim 5, wherein the step 4) is performed directly if the particle size of the silica microsphere having a core-shell structure is a predetermined size, and the step 4) is performed again if the particle size of the silica microsphere having a core-shell structure is not a predetermined size until the particle size of the silica microsphere having a core-shell structure is a predetermined size.
  7. 7. The method of claim 1, wherein in step 4) any one or more of the following conditions are included: 41 The heat treatment is calcination after drying, preferably, the drying temperature is 50-100 ℃, preferably, the calcination temperature is 500-600 ℃, preferably, the calcination time is 4-8 hours; 42 The particle size of the silica microsphere with the core-shell structure and the hierarchical pore is 1-2 mm; 43 The mechanical strength of the silica microsphere with the core-shell structure and the hierarchical pore is 2.0-15.0N; 44 The silica microsphere with the core-shell structure and the hierarchical pores is a microsphere with a shell structure comprising mesoporous size pore channels and/or microporous size pore channels.
  8. 8. The silica microsphere with a core-shell structure and a hierarchical pore is characterized in that the silica microsphere with a core-shell structure and a hierarchical pore is prepared by the preparation method according to any one of claims 1-7.
  9. 9. Use of silica microspheres with core-shell structure and hierarchical pores according to claim 8 in cigarette flavoring.
  10. 10. A cigarette comprising the silica microsphere of claim 8 having a core-shell structure and a hierarchical pore.

Description

Silica microsphere with core-shell structure and hierarchical pores, and preparation method and application thereof Technical Field The invention relates to the technical field of tobacco materials, in particular to a silicon dioxide microsphere with a core-shell structure and a hierarchical pore, and a preparation method and application thereof. Background Along with the continuous improvement of the living standard of people, cigarette consumers have higher requirements on the quality of cigarettes, which not only relates to the basic taste of the cigarettes, but also relates to the aspects of aroma, health and the like. In the cigarette manufacturing process, in order to increase the aroma of the cigarettes and improve the taste, substances such as natural porous materials, plant starch or supermolecular gel and the like are usually added into the filter stick so as to achieve the effects of enhancing aroma and preserving moisture. However, these conventional materials have some drawbacks in practical application, especially in terms of high temperature resistance, and in high temperature environment, structural stability of the materials is affected, so that overall quality and safety of cigarettes are affected. In addition, certain materials may generate micro-nano-sized particles during the molding process, which may present health risks if inhaled into the human body. The traditional fragrance-carrying materials also have other problems such as low mechanical strength, limited fragrance carrying amount, poor slow release performance and the like, and the problems limit the improvement of the quality and the fragrance type taste of cigarettes. For example, the fragrance-carrying material with insufficient mechanical strength is easy to break in the processing process, so that the distribution uniformity of the fragrance-carrying material in the cigarette is influenced, the fragrance-carrying effect of the cigarette is further influenced, the fragrance-carrying material with limited fragrance carrying quantity and poor slow release performance can cause unstable release of fragrance in the combustion process of the cigarette, the fragrance is strong and weak in the smoking process of a smoker, and the overall smoking experience is further influenced. Disclosure of Invention In view of the above-described drawbacks of the prior art, an object of the present invention is to provide a silica microsphere having a core-shell structure and a hierarchical pore, and a preparation method and use thereof, for solving the problems in the prior art. To achieve the above and other related objects, the present invention firstly provides a method for preparing silica microspheres having a core-shell structure and hierarchical pores, the method comprising the steps of: 1) Mixing polyvinyl alcohol aqueous solution with nano silicon dioxide particles, and stirring to form floccules; 2) Preparing the floccule obtained in the step 1) into spheres, namely a nuclear structure of the silicon dioxide microspheres; 3) Wrapping the mixture of the pre-mixed mesoporous silica particles and the pore-forming agent on the surface of the nuclear structure prepared in the step 2) to be used as a shell structure of the silica microsphere, so as to obtain the silica microsphere containing the nuclear shell structure; 4) And (3) performing heat treatment to form multistage holes on the core-shell structure of the silica microsphere, thereby obtaining the silica microsphere with the core-shell structure and the multistage holes. The invention also provides the silica microsphere with the core-shell structure and the hierarchical pore, which is obtained by the preparation method The invention also provides application of the silica microsphere with the core-shell structure and the hierarchical pores in cigarette flavoring. The invention also provides a cigarette, which comprises the silica microsphere with the core-shell structure and the hierarchical pores. As described above, the silica microsphere with the core-shell structure and the hierarchical pores, as well as the preparation method and the application thereof, have the following beneficial effects: 1) The silica microsphere with the core-shell structure and the hierarchical pores provided by the invention has a core-shell structure with nano silica as a core and mesoporous silica as a shell, and has ultrahigh temperature resistance; 2) The shell structure of the microsphere can prevent nano powder from entering the body in the sucking process, and simultaneously improve the mechanical strength of the material; 3) The microsphere has multistage pore channels with different sizes and higher specific surface area, so that the fragrance-carrying material can more easily enter the sphere, is easily adsorbed by mesoporous pore channels in the material, can improve the fragrance carrying amount and improve the slow release performance; 4) The microsphere adopts mesoporous silica nano par