High-retention long-acting slow-release mint essence core-shell type double-layer structure particle and preparation method thereof

Abstract

The invention belongs to the field of functional materials and essence carriers, and provides a high-retention long-acting slow-release mint essence core-shell type double-layer structure particle and a preparation method thereof.The high-retention long-acting slow-release mint essence core-shell type double-layer structure particle is characterized in that a filling layer is arranged in a shell, and a plurality of hollow aluminum oxide microsphere master batches are arranged in the filling layer; the shell and the filling layer are prepared from the following raw materials: silicon dioxide, crosslinked starch, soluble starch, bentonite and porous silicon dioxide micro powder. The produced particles have the characteristics of static high strength and dynamic easy breaking, can be used as an efficient essence adsorption carrier, and can be applied to food seasoning, daily chemical aromatherapy, air freshening and other products.

Description

Technical Field

[0001] This invention belongs to the field of functional materials and fragrance carriers, and relates to a core-shell bilayer structure particle with high retention and long-lasting sustained-release peppermint fragrance and its preparation method. Specifically, it relates to a technology for preparing composite spherical adsorbent particles containing independent cavity masterbatch. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] The core requirements for fragrance adsorption carriers are "high porosity, structural stability, large adsorption capacity, and long fragrance retention time." Simultaneously, in fragrance application scenarios, there is a contradictory need to meet the requirements of "high structural strength during static storage (resistance to transportation breakage) and easy breakage during dynamic use (promoting rapid fragrance release)." Currently, most mainstream carriers in the industry are single porous materials (such as silica, activated carbon, and porous starch), relying on the interconnected pores of the material itself to adsorb fragrances. However, this approach suffers from three major problems: First, interconnected pores easily lead to fragrance volatilization, resulting in low long-term storage retention (≤65%). Second, the pore structure is easily affected by temperature and humidity, leading to collapse and poor static stability. Third, the carriers are either too rigid overall (such as ceramic carriers), resulting in slow fragrance release during use, or too soft overall (such as starch carriers), making them prone to breakage during storage. Therefore, it is impossible to balance the requirements of "static strength" and "dynamic fragility."

[0004] To address this, some studies have used sodium silicate as a raw material to prepare porous silica particles via a template method. However, this single porous material exhibits low fragrance retention, and its dense overall structure makes it difficult to break during use, resulting in a fragrance release rate ≤0.05 g / (g). h), low release efficiency.

[0005] One study prepared a starch-based composite carrier by extruding and granulating a compound of starch and bentonite. Although it is easily broken during use (compressive strength ≤15N), starch is prone to absorbing moisture and softening in humid environments, and is easily carbonized at high temperatures (>120℃), making it impossible to set at high temperatures. The breakage rate is ≥10% during static storage, and the adsorption capacity is ≤1.5g / g.

[0006] Some studies have used alumina and silica sintering at high temperatures (1200-1400℃) to prepare porous ceramic carriers, but the overall structure is hard and almost does not break during use, and the fragrance release cycle is >30 days, which cannot meet the requirements for rapid release.

[0007] Some studies have used cavity materials such as hollow glass microspheres and polystyrene microspheres. Although they have independent cavities, hollow glass microspheres are fragile (static breakage rate ≥8%), and polystyrene microspheres melt and collapse at >200℃. In addition, they have poor compatibility with starch and silica shells, making it impossible to composite them. Furthermore, it is impossible to balance the requirements of "static strength" and "dynamic breakage".

[0008] Therefore, there is an urgent need to develop a new type of fragrance adsorption carrier that is "statically high-strength and dynamically fragile". Summary of the Invention

[0009] To address the aforementioned issues, this invention provides a high-retention, long-lasting, sustained-release peppermint flavor core-shell bilayer structure particle and its preparation method. The particles produced by this invention possess both "high static strength and easy dynamic breakage" characteristics, and can be used as a highly efficient flavor adsorption carrier for applications in food flavoring, daily chemical fragrances, air fresheners, and other products.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a core-shell type double-layer structure particle with high retention and long-lasting sustained release of peppermint flavor, wherein a filling layer is provided inside the shell, and a plurality of hollow alumina microsphere masterbatches are provided inside the filling layer; The shell and filling layer are prepared from the following raw materials: silica, cross-linked starch, soluble starch, bentonite, and porous silica micro powder.

[0011] This invention presents core-shell double-layer structure particles with "independent cavity clusters + controllable breakage structure"—the independent cavities can physically lock fragrance molecules, significantly reducing volatilization loss, while the cavity clusters can increase adsorption capacity; and the controllable breakage structure, through material ratios and process design, achieves "static high strength and dynamic easy breakage." This solves the problems of traditional independent cavity materials being prone to collapse at high temperatures or having poor compatibility with the shell material, making them difficult to adapt to composite molding and high-temperature setting processes, and further hindering the controllable adjustment of "static-dynamic" performance.

[0012] A second aspect of the present invention provides a method for preparing core-shell bilayer structured particles of highly retained, long-lasting, sustained-release peppermint flavor, comprising: Pretreatment of the masterbatch; Mix silica, cross-linked starch, soluble starch, bentonite, and porous silica powder, sieve, add water, and mix evenly to obtain the outer shell powder. The outer shell powder and the pretreated masterbatch are kneaded in a twin-screw mill to obtain a composite material; The composite material is screw-extruded and cut to obtain a blank. The raw material is then subjected to high-temperature shaping in sections to obtain the final product.

[0013] A third aspect of the present invention provides the application of the above-mentioned high-retention, long-lasting, sustained-release menthol flavor core-shell bilayer structure particles in the tobacco, food, and daily chemical industries.

[0014] Beneficial effects of the present invention (1) Significantly improved load efficiency: This invention utilizes a dual adsorption structure of "independent cavity of masterbatch (hollow rate ≥95%) + porous silica micropowder micropores in the outer shell," achieving a fragrance adsorption capacity ≥2.0g / g (compared to ≤1.5g / g in traditional processes) and an effective loading rate ≥90% (compared to ≤70% in traditional processes). Furthermore, during static storage, the physical barrier of the outer shell and the sealed cavity structure ensure a fragrance retention rate ≥80% after 30 days and ≥70% after 60 days. This addresses the problems of "low loading capacity and poor retention rate" in existing technologies, significantly improving fragrance utilization efficiency.

[0015] (2) Resolving the contradiction between "static high strength and dynamic fragility": This invention achieves a balance between two key properties through material ratio (cross-linked starch + soluble starch) and process control (kneading time, extrusion speed, and setting temperature): static compressive strength ≥30N (transport breakage rate ≤2%) and dynamic breaking force ≤15N (fragrance release rate ≥60% within 1 hour after being subjected to force). It exhibits structural stability during static storage, resisting breakage during transportation and storage; however, it is easily broken during dynamic use (such as chewing, friction, and extrusion), rapidly releasing the fragrance from the cavity and micropores. This addresses the core pain point of traditional processes, which often result in either difficult release or easy breakage, and is suitable for fragrance release needs in various scenarios, including food (such as chewing gum and mints) and daily chemicals (such as friction-release aromatherapy).

[0016] (3) Enhanced structural stability and scene adaptability: The particles of this invention have a compressive strength of ≥30N, can withstand water immersion for 24 hours without loosening, and have a moisture content of ≤5%, making them suitable for various scenarios such as humidity and high temperature; at the same time, the food-grade raw materials can directly contact food, thus broadening the application range.

[0017] (4) The preparation method of the present invention is simple, practical and easy to promote. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. Exemplary embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 A schematic diagram of the cross-sectional structure of the composite spherical particles, wherein: 1. Outer shell and filling layer (silica + cross-linked starch + soluble starch + bentonite + porous silica micro powder); 2. Hollow alumina microsphere masterbatch.

[0020] Figure 2Cross-sectional view of composite spherical particles. Detailed Implementation

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they are used in accordance with conventional methods in the art or product instructions. Similarly, unless otherwise specified, the test methods of this invention are performed in accordance with conventional methods in the art or industry-standard methods or practices. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0023] As described in the background section, traditional carriers have the following problems: 1. Low loading efficiency: Traditional carriers are mostly interconnected pores or single cavity structures with an adsorption capacity of ≤1.5g / g. Moreover, fragrances are easily attached to the surface of the pores, resulting in an actual effective loading rate of ≤70%, which cannot achieve high-efficiency loading. At the same time, during static storage, structural defects can easily lead to premature loss of fragrances, further reducing the effectiveness of loading.

[0024] 2. The contradiction between "static strength and dynamic breakage" cannot be balanced: either the static strength is low (starch-based ≤15N), resulting in a high breakage rate during storage; or the dynamic breakage is difficult (ceramic-based ≥50N), leading to slow fragrance release. No carrier can meet the dual requirements of "static compressive strength ≥30N (breakage resistance) and dynamic breakage force ≤15N (easy release)".

[0025] 3. Insufficient cavity material performance: Existing cavity materials are either prone to collapse at high temperatures (polymer microspheres) or are fragile and dense (hollow glass microspheres), which cannot meet the requirements of "high temperature shaping without collapse and controllable structural strength". In addition, they have poor compatibility with the outer shell material and are difficult to composite molding.

[0026] 4. Poor process adaptability: High-temperature shaping requires extremely high temperatures (ceramic sintering > 1000℃), resulting in high energy consumption; the shell and masterbatch are prone to sticking to the equipment when compounded, resulting in low molding efficiency, and it is impossible to achieve precise adjustment of "static-dynamic" performance through process control.

[0027] Therefore, the present invention provides a core-shell type double-layer structure particle with high retention and long-lasting sustained release of peppermint flavor, wherein a filling layer is provided inside the shell, and a plurality of hollow alumina microsphere masterbatches are provided inside the filling layer; The shell and filling layer are prepared from the following raw materials: silica, cross-linked starch, soluble starch, bentonite, and porous silica micro powder.

[0028] The composition of the filler layer affects the mechanical properties and breakage performance of the structural particles. In order to achieve the effect of "static high strength - dynamic easy breakage", this invention has conducted a systematic study on existing filler materials. Through large-scale exploration, it was found that using silica, cross-linked starch, soluble starch, bentonite, and porous silica micro powder as raw materials, combined with the ratio and process control, can achieve the effect of "static high strength - dynamic easy breakage". Preferably, the mass ratio of silica, cross-linked starch, soluble starch, bentonite, and porous silica micro powder is (350-400):(220-270):(30-80):(60-110):(50-120) to obtain the expected effect of "static high strength - dynamic easy breakage".

[0029] This invention develops a "masterbatch-shell composite molding + structure control" process to resolve the contradiction between "static strength and dynamic breakage," achieving "static compressive strength ≥30N (resistant to transport breakage) and dynamic breakage force ≤15N (easily releases fragrance)." Therefore, this invention also provides a method for preparing high-retention, long-lasting, sustained-release peppermint fragrance core-shell bilayer structure particles, comprising: Pretreatment of the masterbatch; Mix silica, cross-linked starch, soluble starch, bentonite, and porous silica powder, sieve, add water, and mix evenly to obtain the outer shell powder. The outer shell powder and the pretreated masterbatch are kneaded in a twin-screw mill to obtain a composite material; The composite material is screw-extruded and cut to obtain a blank. The raw material is then subjected to high-temperature shaping in sections to obtain the final product.

[0030] The proportion of filler material affects the mechanical properties and crushing performance of structural particles. Therefore, this invention studies the proportion of silica, cross-linked starch, soluble starch, bentonite, porous silica powder and water. Preferably, the mass ratio of silica, cross-linked starch, soluble starch, bentonite, porous silica powder and water is (350-400):(220-270):(30-80):(60-110):(50-120):(230-280) to improve the static strength of the material and reduce the dynamic crushing force.

[0031] This invention selects masterbatch materials with self-contained cavities that can be shaped without collapsing at high temperatures (200-500℃) and have controllable structural strength, and constructs "independent cavity clusters" to improve the fragrance loading efficiency (adsorption capacity ≥2.0g / g, effective loading rate ≥90%). Preferably, the hollow rate of the masterbatch is ≥95% to obtain a better loading effect.

[0032] The amount of masterbatch used affects its loading capacity and retention rate. Therefore, the present invention has studied the amount of masterbatch used. Preferably, the amount of masterbatch used accounts for 45%-50% of the total mass of masterbatch and shell powder, so as to better improve the loading capacity and retention rate.

[0033] The kneading time affects the mechanical properties and crushing performance of the structural particles. Therefore, this invention studies the kneading conditions. Preferably, the kneading conditions are a temperature of 25-30℃, a rotation speed of 20-30 r / min, and a time of 10-15 min, in order to obtain better static strength and reduce dynamic crushing force.

[0034] The extrusion speed affects the mechanical properties and crushing performance of the structural particles. Therefore, this invention studies the extrusion conditions. Preferably, the extrusion conditions are a die diameter of 3-5 mm, a temperature of 30-35℃, and a rotation speed of 15-20 r / min, in order to better improve the static strength and reduce the dynamic crushing force.

[0035] The high-temperature setting process (temperature ≤ 500℃) is optimized to reduce energy consumption, ensure the granules are water and temperature resistant, and adapt to multiple scenarios. Simultaneously, the load efficiency and crushing performance are adjusted through process parameters to meet the needs of different fragrance applications. Preferably, the specific steps of the segmented high-temperature setting process include: Preheating: 100-120℃, 1-2 hours; Air evaporation: 200-250℃, 2-3 hours; Shaping and strengthening: 300-380℃, 1.5-2h, cooling, and the product is obtained.

[0036] More specifically, including: Step 1: Pretreatment of cavity masterbatch Screening: The masterbatch is passed through a 100-mesh sieve to remove particles <80μm or >220μm to ensure uniform particle size and avoid uneven stress during dynamic crushing; Drying: Dry with hot air at 80-100℃ for 1-2 hours, with a moisture content ≤2%, to avoid clumping and affecting dispersion; Quality control: The static compressive strength of the masterbatch is ≥20N / particle, the dynamic crushing force is ≤15N / particle, and the cavity ratio is ≥60%, which lays the foundation for efficient load and controllable crushing.

[0037] Step 2: Preparation of outer shell material Mixing: Mix solid components (silica + cross-linked starch + soluble starch + bentonite + porous silica powder) (60 r / min, 15-20 min), and pass through an 80 mesh sieve to ensure uniform dispersion of the load-enhancing components; Adjust viscosity: Add deionized water (15%-25%), stir at 30-40 rpm for 10-15 minutes to achieve a viscosity of 5000-8000 mPa. s moist powder; Step 3: Compound kneading Formula: 45% masterbatch + 55% outer shell powder, added to a twin-screw mixer (25-30℃, 20-30r / min); Kneading: 10-15 min. The interfacial bonding force between the masterbatch and the outer shell is controlled by adjusting the kneading time (kneading for 12-15 min results in strong interfacial bonding and high static strength; kneading for 10-12 min results in weak interfacial bonding and easy dynamic breakage). Quality control: The masterbatch is evenly dispersed (agglomeration rate ≤3%), and there is no exposed masterbatch in the composite material, ensuring that the fragrance enters the cavity and the micropores of the outer shell evenly when loaded.

[0038] Step 4: Extruding into strips and cutting into sections Extrusion: Single screw extruder (die diameter 3-5mm, 30-35℃, 15-20r / min), the density of the strip is controlled by adjusting the screw speed (15-18r / min, density 1.2-1.3g / cm³, high static strength; 18-20r / min, density 1.0-1.2g / cm³, easily broken dynamically); Cutting: The cutter simultaneously cuts the material into 5-8cm short segments (deviation ≤0.5cm), with a smooth surface and no cracks, avoiding uneven density that could affect crushing performance.

[0039] Step 5: Rounding and shaping Equipment: 600mm rolling machine (tilt angle 45-50°, initial speed 15-18r / min); Operation: Add short pieces of material (≤1 / 3 of volume), roll into rounds for 5-8 minutes, spray a small amount of water (5-10 mL) every 2 minutes, and control the particle density by adjusting the rolling speed (15-16 r / min, low density, easy to break; 17-18 r / min, high density, high strength). Quality control: Sphericity ≥ 0.85, diameter 3-5 mm, density 1.1-1.3 g / cm³ (adjustable according to requirements).

[0040] Step 6: Segmented high-temperature setting Preheating: 100-120℃ for 1 hour to remove free water and avoid affecting fragrance adsorption under load; Air evaporation: 200-250℃, 2h, the air in the masterbatch cavity is completely evaporated, forming a hollow cavity and maximizing the load space; Shaping and reinforcement: 300-380℃ (adjust according to masterbatch), 1.5-2h. The curing degree of the shell is controlled by adjusting the shaping temperature and time (300-320℃, 1.5h, low curing degree, easy to break; 350-380℃, 2h, high curing degree, high strength). Cooling: Allow to cool naturally to room temperature, with a moisture content of ≤3%, to avoid moisture absorption affecting load efficiency.

[0041] Step 7: Load efficiency and crushing performance testing Loading efficiency test: Weigh 10g of particles, soak them in peppermint flavor solution (concentration 50%) for 2h, take them out and weigh them, and calculate the adsorption capacity (≥2.0g / g) and effective loading rate (≥90%). Crushing performance testing: Static compressive strength (≥30N) and dynamic crushing force (≤15N) were measured using a particle mechanics testing machine. Unqualified particles were crushed and the process parameters were adjusted to prepare them again. Step 8: Selecting Packaging Screening: 3-5mm sieve; unqualified particles are crushed and reused. Packaging: Sealed bag (with built-in desiccant) to prevent moisture absorption and ensure the cavity is dry before loading.

[0042] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0043] In the following examples, the cross-linked starch was food grade and purchased from Shanghai Jitong International Trade Co., Ltd.

[0044] Soluble starch, product number KL-0217, was purchased from Jinan Xiaoshi Chemical Co., Ltd.

[0045] The porous silica micro powder was purchased from Qinghe County Ruijiang Metal Materials Co., Ltd.

[0046] The flavoring was purchased from Yilun (Shanghai) Flavoring & Fragrance Co., Ltd.

[0047] The masterbatch was placed in the fragrance at a concentration of 1.5 g / L, stirred at 300 r / min and adsorbed for 4 h to obtain the masterbatch adsorbed with fragrance.

[0048] Example 1: Hollow alumina microsphere composite particles 1. Raw material ratio Masterbatch: 450g hollow alumina microspheres (100-200μm, wall thickness 5-8μm, commercially available product); Outer shell: 350g silica + 220g cross-linked starch + 30g soluble starch + 60g bentonite + 50g porous silica powder + 230g deionized water.

[0049] 2. Operating parameters Masterbatch drying: 100℃ / 1.5h, moisture content 1.8%, dynamic crushing force 12N / particle; Shell viscosity: 6500 mPa s, 5% porous silica micro powder (maximizing loading); Kneading: 28℃ / 10min (weak interfacial bonding, easily broken); Extrusion: 18 r / min, strip density 1.1 g / cm³; Setting: 110℃ / 1h→220℃ / 2h→320℃ / 1.5h (low degree of curing, easily broken).

[0050] Example 2: The difference from Example 1 is that the masterbatch is replaced with porous mullite microsphere composite particles.

[0051] Example 3: The difference from Example 1 is that the masterbatch is replaced with hollow cordierite microsphere composite particles.

[0052] Comparative Example 1: The difference from Example 1 is that the masterbatch is replaced with solid porous silica particles (without independent cavities, relying solely on surface micropores for adsorption).

[0053] Characterization method in Experiment Example 1 1. Use a camera to record the appearance and morphology of the particles.

[0054] 2. The effective loading rate and release rate of the flavoring in the particles were determined using gas chromatography.

[0055] 3. Use a particle compressive strength tester to determine the dynamic crushing force of the particles.

[0056] 4. The static compressive strength of a single particle was measured using a particle compressive strength testing machine.

[0057] 5. The granules were stored at room temperature for 30 days. The flavor retention rate of the granules was obtained by calculating the ratio of the flavor loading rate of the granules at the end of storage to the initial loading rate.

[0058]

[0059] The appearance shows that the particles of Examples 1, 2 and 3 all have obvious cavity structures inside, with regular and evenly distributed cavity shapes, and clear overall cross-sections with uniform texture; while the particles of Comparative Example 1 have solid cross-sections with no cavity features, and the cross-sections are rough and irregular in shape.

[0060] In terms of effective loading rate, the effective loading rates of Examples 1-3 were all maintained at around 90%, while that of Comparative Example 1 was only 68.5%. This is because the cavity structure of the Examples provides an independent and sealed storage space for the fragrance, reducing the evaporation loss of the fragrance during loading; while Comparative Example 1 relies solely on the adsorption of the surface micropores of the solid material, which is prone to fragrance loss due to micropore saturation or weak adsorption, resulting in a significantly lower loading efficiency.

[0061] Static compressive strength: The static compressive strength of Examples 1-3 was 31.5-35.6 N, which is 24.5%-40.7% higher than that of Comparative Example 1 (25.3 N). The rigid skeleton of the cavity masterbatch and the outer shell form a synergistic support, ensuring that the particles are not easily broken during storage and transportation; while the solid masterbatch of Comparative Example 1 has a weak bond with the outer shell, and is prone to structural damage due to stress concentration under static conditions.

[0062] Dynamic crushing force: The dynamic crushing force of Examples 1-3 is only 11.5-14.8N, which is 20.9%-38.5% lower than that of Comparative Example 1 (18.7N). The cavity structure can easily achieve "directional crushing" through cavity deformation and skeleton fracture when subjected to force, which meets the rapid release requirements during use (such as compression and friction); while the solid structure of Comparative Example 1 requires a larger external force to crush, making it difficult to achieve efficient aroma release.

[0063] Release rate after 1 hour of crushing: Examples 1-3 reached 60.5%-65.2%, an increase of 43%-54.1% compared with Comparative Example 1 (42.3%); the release rate after 2 hours reached 82.8%-88.7%, an increase of 20.2%-28.7% compared with Comparative Example 1 (68.9%). The fragrance in the cavity is not blocked by micropores after the particles are crushed, and can diffuse and be released quickly; while the fragrance in Comparative Example 1 is adsorbed inside the solid material and needs to slowly penetrate to be released, which is much less efficient than that of the examples.

[0064] Retention rate after 30 days of storage at room temperature: Examples 1-3 were 79.8%-82.5%, which is 28.5%-32.8% higher than Comparative Example 1 (62.1%). The cavity structure can isolate the fragrance from the influence of external water, oxygen and temperature changes, reducing oxidation and volatilization; while the solid material of Comparative Example 1 has micropores that are connected to the outside world, and the fragrance is easily lost due to environmental factors, resulting in poor long-term retention.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-retention, long-lasting, sustained-release peppermint flavor core-shell type double-layer structure particle, characterized in that, The shell contains a filling layer, and the filling layer contains a plurality of hollow alumina microsphere masterbatches; The shell and filling layer are prepared from the following raw materials: silica, cross-linked starch, soluble starch, bentonite, and porous silica micro powder.

2. The high-retention, long-lasting, sustained-release peppermint flavor core-shell bilayer structure particles as described in claim 1, characterized in that, The mass ratio of silica, cross-linked starch, soluble starch, bentonite, and porous silica powder is (350-400): (220-270): (30-80): (60-110): (50-120).

3. A method for preparing high-retention, long-lasting, sustained-release peppermint flavor core-shell bilayer structure particles, characterized in that, include: Pretreatment of the masterbatch; Mix silica, cross-linked starch, soluble starch, bentonite, and porous silica powder, sieve, add water, and mix evenly to obtain the outer shell powder. The outer shell powder and the pretreated masterbatch are kneaded in a twin-screw mill to obtain a composite material; The composite material is screw-extruded and cut to obtain a blank. The raw material is then subjected to high-temperature shaping in sections to obtain the final product.

4. The method for preparing high-retention, long-lasting, sustained-release peppermint flavor core-shell bilayer structure particles as described in claim 1, characterized in that, The mass ratio of silica, cross-linked starch, soluble starch, bentonite, porous silica powder and water is (350-400): (220-270): (30-80): (60-110): (50-120): (230-280).

5. The method for preparing high-retention, long-lasting, sustained-release peppermint flavor core-shell bilayer structure particles as described in claim 1, characterized in that, The hollow fraction of the masterbatch is ≥95%.

6. The method for preparing high-retention, long-lasting, sustained-release peppermint flavor core-shell bilayer structure particles as described in claim 1, characterized in that, The amount of masterbatch used accounts for 45%-50% of the total mass of masterbatch and shell powder.

7. The method for preparing high-retention, long-lasting, sustained-release peppermint flavor core-shell bilayer structure particles as described in claim 1, characterized in that, The kneading conditions are: temperature 25-30℃, rotation speed 20-30 r / min, and time 10-15 min.

8. The method for preparing high-retention, long-lasting, sustained-release peppermint flavor core-shell bilayer structure particles as described in claim 1, characterized in that, The extrusion conditions are: die orifice diameter 3-5mm, temperature 30-35℃, and rotation speed 15-20r / min.

9. The method for preparing high-retention, long-lasting, sustained-release peppermint flavor core-shell bilayer structure particles as described in claim 1, characterized in that, The specific steps of the segmented high-temperature shaping include: Preheating: 100-120℃, 1-2 hours; Air evaporation: 200-250℃, 2-3 hours; Shaping and strengthening: 300-380℃, 1.5-2h, cooling, and the product is obtained.

10. The application of the high-retention, long-lasting, sustained-release menthol flavor core-shell bilayer structure particles as described in claim 1 or 2 in the tobacco, food, and daily chemical industries.

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