Silica gel incense line material as well as preparation method and application thereof

Abstract

The invention provides a silica gel incense line material and a preparation method and application thereof.The silica gel incense line material comprises a silica gel base material, an interface enhancement layer, an intelligent response function layer and a composite aroma system loaded on the surface and inside the intelligent response function layer from inside to outside, the dry basis weight ratio of the silica gel base material to the interface enhancement layer to the intelligent response functional layer to the composite aroma system is 100: (1-5): (5-15): (8-20), and the silica gel base material is a silica gel wire rod subjected to surface hydrophilic treatment and has a porous honeycomb structure; the interface enhancement layer is a copolymer film, and the copolymer film is formed by graft polymerization of acrylic acid and N-vinyl pyrrolidone on the surface of the silica gel substrate; the intelligent response functional layer is a functional layer formed on the interface enhancement layer through in-situ polymerization and comprises a copolymer formed by a temperature-sensitive polymer and a shape memory polymer and mesoporous silica nanospheres loaded with a phase change regulator, and the phase change temperature of the intelligent response functional layer is 35-45 DEG C; and the composite aroma system is a microemulsion containing an aroma core.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of cigarette filter materials, and particularly relates to a silica gel flavor thread material and a preparation method and application thereof. BACKGROUND

[0002] The flavor thread material in the traditional cigarette filter has long been faced with several technical problems difficult to break through. The bonding force between the fiber base material represented by polyester and cotton thread and the flavor components is weak, resulting in the prominent problem that the flavor release is too high in the early stage and obviously insufficient in the later stage. Meanwhile, the heat resistance of such organic fiber is limited, and in the 40-60℃ smoke environment generated during cigarette smoking, the fiber is prone to thermal deformation or degradation, affecting the stability of flavor release. More fundamentally, the surface chemical properties of the fiber material are poor in compatibility with most oil-soluble flavorings, and the flavor components are prone to migration, volatilization or oxidation during storage, resulting in a shortened shelf life of the product.

[0003] The current improvement schemes for these problems all have significant limitations. For example, the microcapsule technology can delay the release of flavor, but the microcapsule wall material increases the smoke flow resistance, affecting the smoking experience, and the rupture behavior of the capsule wall is difficult to accurately control. When the hydrogel material is directly used as a flavor carrier, it is prone to deformation and migration during the formation of the filter rod, affecting the formation quality and appearance of the filter rod. The granular flavor composite material has problems such as difficulty in ensuring uniform distribution and complex processing technology. SUMMARY

[0004] In view of this, the main purpose of the present disclosure is to provide a silica gel flavor thread material and a preparation method and application thereof, so as to at least partially solve at least one of the above-mentioned technical problems.

[0005] To achieve the above-mentioned purpose, the technical scheme of the present disclosure is as follows:

[0006] In one aspect of the present disclosure, a silica gel flavor thread material is provided, which comprises, from inside to outside:

[0007] a silica gel base material, an interface enhancement layer, an intelligent response functional layer, and a composite flavor system loaded on the surface and inside of the intelligent response functional layer, and the dry basis weight ratio of the silica gel base material, the interface enhancement layer, the intelligent response functional layer and the composite flavor system is 100:(1-5):(5-15):(8-20), wherein,

[0008] the silica gel base material is a silica gel thread material after surface hydrophilic treatment, and the silica gel thread material has a porous honeycomb structure;

[0009] the interface enhancement layer is a copolymer film formed by graft polymerization of acrylic acid and N-vinyl pyrrolidone on the surface of the silica gel base material;

[0010] The intelligent response function layer is a function layer formed on the interface enhancement layer by in-situ polymerization, and includes a copolymer of a temperature-sensitive polymer and a shape memory polymer, and mesoporous silica nanospheres loaded with a phase change regulator, and the phase change temperature of the intelligent response function layer is 35-45 DEG C.

[0011] The composite aroma system is a microemulsion containing an aroma core.

[0012] In another aspect of the present disclosure, a preparation method of the above-mentioned silica gel aroma wire material is provided, comprising:

[0013] The methyl vinyl silicone rubber raw rubber, hydrophobic reinforcing agent, crosslinking agent and colorant are mixed and extruded into a shape and then segmented vulcanized to obtain a silica gel base material;

[0014] The silica gel base material is immersed in an aqueous solution containing acrylic acid and N-vinyl pyrrolidone monomers, and a grafting polymerization reaction is carried out under the irradiation of ultraviolet light for 1-3 hours at 40-60 DEG C in an anaerobic environment to form an interface enhancement layer;

[0015] On the interface enhancement layer, a solution containing a temperature-sensitive polymer, a shape memory polymer, mesoporous silica nanospheres loaded with a phase change regulator and a crosslinking agent is formed into an intelligent response function layer by in-situ polymerization;

[0016] The composite aroma system of the microemulsion is loaded on the surface and inside of the intelligent response function layer by stepwise immersion, and the silica gel aroma wire material is obtained after washing, drying and winding.

[0017] In still another aspect of the present disclosure, an application of the above-mentioned silica gel aroma wire material in a filter rod fixture for cigarettes is provided.

[0018] According to the silica gel aroma wire material provided by the present disclosure, a multi-layer structure is constructed to provide stable mechanical support and aroma loading space by using a porous honeycomb structure silica gel base material, the interface enhancement layer improves the inertness of the silica gel surface and ensures firm combination between layers, the intelligent response function layer realizes intelligent regulation and control of aroma release based on temperature change, and the composite aroma system guarantees the stability and long-acting property of the aroma through the microemulsion containing an aroma core, thereby synergistically realizing precise control, uniform release and long-lasting aroma of aroma substances and significantly improving the comprehensive performance of the product. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present disclosure more clear and explicit, the present disclosure is further described in detail below with specific examples.

[0020] The endpoints of the ranges and any values disclosed in the disclosure are not limited to the precise values recited as the exact range or value should be understood as being encompassed by the ranges or values near them. For ranges, the endpoints are included within the ranges, and the endpoints are included with the single points within the ranges, and the single points are included with each other as new ranges should be considered as being specifically disclosed.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the term "includes" and tautological equivalents thereof, means that the claimed features, steps, operations, and / or components are present, but does not exclude the presence or addition of one or more other features, steps, operations, or components.

[0022] In traditional cigarette filter aroma threads, fiber substrates such as polyester and cotton threads are prone to uneven aroma release due to weak surface binding force, resulting in a phenomenon of "concentration at the beginning and dilution at the end". Meanwhile, they have poor heat resistance and are prone to deformation or degradation in a high-temperature smoke environment, affecting the release stability. In addition, these materials have poor compatibility with oily flavors, and aroma components are prone to volatilization or oxidation during storage, shortening the product shelf life. Although existing improvement technologies such as microcapsules, hydrogels, or particle composite materials exhibit certain slow-release effects in the laboratory, they still generally have poor processing adaptability, are prone to deformation and migration, have uneven distribution, or have complex processes, making it difficult to meet the requirements of industrial production. Therefore, research has shifted to silica gel materials with excellent mechanical strength, heat resistance, and chemical stability to seek a fundamental breakthrough.

[0023] However, although silica gel materials have been widely used in the industrial field for products such as seals and medical catheters, their inherent hydrophobicity and dense surface characteristics have severely limited their application in aroma loading. Based on this, the present disclosure provides a silica gel aroma thread material and its preparation method and application, which effectively improves the specific surface area and forms through microchannels by constructing a porous honeycomb structure of silica gel substrate, significantly enhancing the aroma loading capacity while maintaining the mechanical properties of the material. To further improve the interlayer bonding force, an interface reinforcement layer is constructed on the surface of the substrate by plasma activation and graft polymerization, realizing stable transition from the substrate to the functional layer. On this basis, an intelligent response functional layer is formed by in-situ polymerization, which introduces temperature-sensitive polymers, shape memory polymers, and mesoporous silica nanospheres loaded with phase change regulators, enabling it to have phase change characteristics in the range of 35-45°C, thereby realizing intelligent regulation of aroma release behavior.

[0024] In terms of aroma system construction, the aroma core is encapsulated into a microemulsion with high stability and uniform particle size through microemulsification technology, and is effectively loaded into the functional layer by means of stepwise impregnation process. Finally, through the synergistic effect of the above multi-layer structure, precise control, uniform release and long-term stability of the aroma substance are realized. The corresponding preparation method of the silica gel fragrance line material combines key technologies such as segmented vulcanization, plasma grafting, in-situ copolymerization and stepwise impregnation, and has good controllability and industrial adaptability. When applied to a cigarette filter rod, the prepared silica gel fragrance line material exhibits uniform and stable aroma release, excellent high-temperature resistance and long storage life, effectively overcoming the technical bottlenecks of traditional fragrance line products.

[0025] According to an embodiment of one aspect of the present disclosure, a silica gel fragrance line material is provided, which comprises, from inside to outside: a silica gel base material, an interface enhancement layer, a smart response functional layer, and a composite aroma system loaded on the surface and inside of the smart response functional layer, and the dry basis weight ratio of the silica gel base material, the interface enhancement layer, the smart response functional layer and the composite aroma system is 100:(1-5):(5-15):(8-20), wherein the silica gel base material is a silica gel wire material with a hydrophilic surface treatment, and the silica gel wire material has a porous honeycomb structure; the interface enhancement layer is a copolymer film formed by graft polymerization of acrylic acid and N-vinyl pyrrolidone on the surface of the silica gel base material; the smart response functional layer is a functional layer formed on the interface enhancement layer by in-situ polymerization, which comprises: a copolymer of a temperature-sensitive polymer and a shape memory polymer, and mesoporous silica nanospheres loaded with a phase change regulator, and the phase transition temperature of the smart response functional layer is 35-45℃; and the composite aroma system is a microemulsion containing an aroma core.

[0026] According to an embodiment of the present disclosure, the silica gel fragrance line material sequentially constructs a silica gel base material, an interface enhancement layer, a smart response functional layer, and a composite aroma system loaded on the surface and inside of the smart response functional layer, which together synergistically realize precise control and long-term slow release of aroma substances. Among them, the appropriate weight ratio of the silica gel base material, the interface enhancement layer, the smart response functional layer and the composite aroma system can balance the aroma loading capacity and release control ability on the premise of ensuring the stability of the structure, so that each functional layer plays a synergistic effect in mechanical support, interface combination, temperature-sensitive response and aroma coating, thereby significantly improving the comprehensive performance of the fragrance line material.

[0027] Specifically, a porous honeycomb structure of silicone wire was first constructed to address the substrate issue for aroma loading. The porous honeycomb structure not only significantly increases the specific surface area, providing ample attachment sites for aroma components, but its interconnected microchannel structure also establishes excellent material transport pathways. This structural design allows the silicone material to achieve ideal aroma loading capacity while maintaining excellent mechanical properties. After constructing the porous silicone wire, hydrophilic treatment was then applied to generate active sites on the silicone surface, introducing polar groups and improving its surface properties.

[0028] Subsequently, a stable copolymer film is formed on the surface of the silicone substrate through graft polymerization. This gradient transition achieves a smooth transition from the inert silicone surface to the hydrophilic functional layer, effectively solving the technical challenge of weak interlayer bonding and laying the foundation for the stable construction of subsequent functional layers.

[0029] Furthermore, a smart responsive functional layer was constructed on the interface enhancement layer. By synergistically polymerizing thermosensitive materials with materials possessing shape memory properties, a three-dimensional network structure with temperature-responsive characteristics was created. This smart responsive functional layer undergoes a reversible volume change when the ambient temperature reaches the phase transition temperature, thereby achieving intelligent regulation of the aroma release rate. In addition, the introduction of mesoporous silica nanospheres as a carrier for the phase transition modifier further refined the network's response behavior, making the aroma release curve more stable and controllable.

[0030] For complex aroma systems, the uniformity of microemulsions at the microscale not only ensures the stable dispersion of aroma components, but also allows aroma components to fully penetrate into all parts of the functional layer network, achieving efficient loading and stable release of aroma.

[0031] According to embodiments of this disclosure, the silicone substrate comprises, by weight, 100 parts of methyl vinyl silicone rubber raw rubber, 15-25 parts of hydrophobic reinforcing agent, 0.8-1.5 parts of crosslinking agent, and 2-4 parts of colorant, wherein the specific surface area of ​​the hydrophobic reinforcing agent is 150-300 m². 2 / g.

[0032] Optionally, the hydrophobic reinforcing agent can be, for example, 15 parts, 18 parts, 20 parts, 23 parts, 25 parts, etc.; the crosslinking agent can be, for example, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, etc.; and the colorant can be, for example, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, etc. The above-mentioned appropriate proportions can ensure the formation of a stable porous honeycomb structure in the silicone substrate while optimizing its mechanical strength, vulcanization efficiency, and appearance uniformity, thereby providing a structurally complete and reliable substrate support for the subsequent construction of functional layers and the efficient loading of aroma.

[0033] The hydrophobic reinforcing agent includes any one of hydrophobic fumed silica, hydrophobic precipitated silica, and silica powder treated with a silane coupling agent, and is used to enhance the mechanical strength of the substrate and maintain the stability of the porous structure. The specific surface area of the hydrophobic reinforcing agent can be, for example, 150 m 2 / g, 200 m 2 / g, 230 m 2 / g, 250 m 2 / g, 280 m 2 / g, 300 m 2 / g, etc. An appropriate specific surface area can strike a balance between the reinforcing effect and dispersibility, and ensure the formation of a uniform and stable porous network structure.

[0034] The cross-linking agent includes any one of 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane, dicumyl peroxide, and bis-(tert-butyl peroxyisopropyl) benzene, and is used to form a stable three-dimensional cross-linked network during the preparation of the silica gel substrate, and endow the silica gel substrate with good elasticity and heat resistance.

[0035] The coloring agent includes any one of red iron oxide, yellow iron oxide, and carbon black, and is used to provide uniform product color and assist in judging the degree of material dispersion.

[0036] According to an embodiment of the present disclosure, the porosity of the silica gel substrate is 20% to 40%, for example, 20%, 25%, 30%, 35%, 40%, etc.; the pore size is 50 to 200 μm, for example, 50 μm, 80 μm, 100 μm, 150 μm, 200 μm, etc.; and micro-channels with a width of 5 to 20 μm are arranged between the pores, for example, 5 μm, 10 μm, 15 μm, 20 μm, etc.

[0037] An appropriate pore structure can significantly increase the specific surface area to provide sufficient aroma loading sites while ensuring the mechanical strength of the substrate, and the three-dimensional through micro-channel network formed is conducive to the uniform distribution and controllable release of aroma substances, thereby laying a structural foundation for realizing long-acting and slow-release of aroma.

[0038] According to an embodiment of the present disclosure, the silica gel substrate further includes 1 to 3 parts of a surface treatment agent, thereby improving the dispersibility and compatibility of the hydrophobic reinforcing agent in the raw silica rubber, enhancing the interface bonding between the filler and the matrix, and thereby improving the processing performance and the final mechanical strength of the silica gel substrate.

[0039] The surface treatment agent is a compound of hexamethyldisilazane and γ-aminopropyl triethoxysilane in a weight ratio of 2-4:1. The specific compound system can synergize, hexamethyldisilazane can effectively treat the surface silicon hydroxyl of the reinforcing agent, reduce its agglomeration tendency, and γ-aminopropyl triethoxysilane can produce stronger interaction with the rubber matrix through its organic functional group, and together ensure the uniform dispersion of the reinforcing agent and the formation of a stable interface.

[0040] According to an embodiment of the present disclosure, the weight ratio of acrylic acid to N-vinyl pyrrolidone in the composition of the interface enhancement layer is 6:1 to 1:3, for example, which can be 6:1, 4:1, 2:1, 1:1, 1:3, etc. By adjusting the ratio of the two, the balance of hydrophilicity and hydrophobicity and the functional group density of the interface enhancement layer can be adjusted, thereby optimizing the compatibility and bonding strength between the hydrophobic silica gel substrate and the hydrophilic smart response functional layer. For example, a higher proportion of acrylic acid helps to enhance the hydrophilicity and interface polarity; and a higher proportion of N-vinyl pyrrolidone can improve flexibility and biocompatibility.

[0041] In actual application, when preparing the interface enhancement layer, for example, 1-3 parts of acrylic acid, 0.5-3 parts of N-vinyl pyrrolidone, and 50-100 parts of deionized water can be used.

[0042] According to an embodiment of the present disclosure, the smart response functional layer is formed by in-situ copolymerization of 5-8 parts of temperature-sensitive polymer, 1-3 parts of shape memory polymer, 0.1-0.5 parts of mesoporous silica nanospheres loaded with phase change regulator, 0.012-0.064 parts of crosslinking agent, and 80-150 parts of deionized water.

[0043] The temperature-sensitive polymer includes N-isopropyl acrylamide, for example, which can be 5 parts, 6 parts, 7 parts, or 8 parts. As the main response material of the smart response functional layer, its content directly affects the phase transition temperature and response sensitivity. This dosage range can ensure significant and controllable volume changes within a set temperature range (e.g., 35-45°C).

[0044] The shape memory polymer includes polycaprolactone-polyurethane block copolymer, for example, which can be 1 part, 1.5 parts, 2 parts, 2.5 parts, or 3 parts. It synergizes with the temperature-sensitive polymer to enhance the mechanical strength and shape recovery of the network structure, helping to restore the structure after aroma release and ensuring the repeatability of the release behavior.

[0045] The crosslinking agent includes N,N'-methylenebisacrylamide, for example, which can be 0.012 parts, 0.02 parts, 0.04 parts, 0.06 parts, or 0.064 parts, etc. It is used to build a stable smart response functional layer structure, and its amount can control the polymerization crosslinking density. Too low a dosage will result in insufficient mechanical strength, and too high a dosage will affect the response amplitude.

[0046] The mesoporous silica nanospheres loaded with the phase change modifier may be, for example, 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, etc. Among them, the phase change modifier includes n-tetradecane, and the loading amount is 20% to 40% of the weight of the mesoporous silica nanospheres. The phase change modifier loaded in the mesoporous silica undergoes reversible solid-liquid phase change at a specific temperature, absorbs or releases heat to buffer temperature fluctuations, thereby smoothing the volume change process of the intelligent response functional layer, and making the fragrance release curve more stable.

[0047] According to an embodiment of the present disclosure, the intelligent response functional layer further contains 0.05 to 0.3 parts of thermochromic microcapsules, for example, 0.05 parts, 0.1 parts, 0.2 parts, 0.3 parts, etc.

[0048] In order to improve the use experience of the product, thermochromic microcapsules can be introduced into the intelligent response functional layer as a visual indication system. When the ambient temperature reaches the color change temperature, the microcapsules undergo reversible color change, not only providing intuitive quality feedback for consumers, but also realizing real-time monitoring of the use state of the product, increasing the additional use value while maintaining the basic functions of the product, and embodying the design concept of people-oriented.

[0049] The particle size of the thermochromic microcapsules is 1 to 10 μm, the shell material of the thermochromic microcapsules is a gelatin-arabic gum composite, the core material is a crystal violet lactone-bisphenol A color developing system, and the color change temperature is 40 to 50℃. The microcapsules directly indicate whether the ambient temperature reaches the fragrance release interval through color change, and the micron-level particle size and the composite shell material structure ensure the stability and color developing reversibility during processing and use.

[0050] According to an embodiment of the present disclosure, the droplet particle size of the microemulsion is 50 to 200 nm, and the microemulsion is prepared by mixing a fragrance core, a stabilizing layer, a protective layer, and an emulsifier.

[0051] The fragrance core includes any one of menthol, tobacco extract essence, coffee essence, cocoa essence, and fruit essence, wherein the fruit essence includes strawberry, blueberry, watermelon, etc. As the content of the microemulsion, the required fragrance or flavor function is provided.

[0052] The stabilizing layer includes any one of lecithin, stearic acid monoglyceride, and sorbitan monooleate, and the lecithin and other surfactant molecules are lipophilic on one end and hydrophilic on the other end, can form a dense arrangement between the interface of the oil-based fragrance core droplets and the water phase, effectively block the penetration of oxygen molecules, and thus maintain the stability of the emulsion.

[0053] The protective layer comprises any one of hydroxypropyl-β-cyclodextrin, methyl-β-cyclodextrin, chitosan, and cyclodextrin and the like materials wrap the aroma core through molecular inclusion, effectively prevent the oxidation and volatilization of the aroma, thereby significantly improving the storage stability and realizing long-acting and slow-release of the aroma.

[0054] The emulsifier comprises any one of Tween 80, polyoxyethylene sorbitan monostearate, and sorbitan monolaurate, which reduces the interfacial tension between oil and water, helps the stable layer to make the oil phase more easily dispersed into nanodroplets, and forms steric hindrance or electrostatic repulsion in the emulsion, further preventing the aggregation of droplets and ensuring long-term uniform stability of the microemulsion.

[0055] By combining the aroma core, the stable layer, and the protective layer, a stable triple-coating structure is formed, which significantly improves the retention rate of the aroma component during storage and solves the problems of easy volatilization and easy oxidation of the aroma.

[0056] According to another aspect of the embodiment of the present disclosure, a preparation method of the above-mentioned silica gel fragrance line material is provided, comprising the following steps (1) to (4).

[0057] Step (1): according to the weight fraction, methyl vinyl silicone rubber raw rubber, hydrophobic reinforcing agent, crosslinking agent, and colorant are mixed, extruded, and segmented vulcanized, and then subjected to surface hydrophilic treatment to obtain a silica gel base material;

[0058] Step (2): the silica gel base material is immersed in an aqueous solution containing acrylic acid and N-vinyl pyrrolidone monomers, and subjected to graft polymerization under ultraviolet irradiation for 1 to 3 hours in an anaerobic environment at 40 to 60°C to form an interfacial reinforcing layer;

[0059] Step (3): a solution containing a temperature-sensitive polymer, a shape memory polymer, mesoporous silica nanospheres loaded with a phase change regulator, and a crosslinking agent is formed into an intelligent response functional layer by in-situ polymerization on the interfacial reinforcing layer;

[0060] Step (4): the composite aroma system of the microemulsion is loaded on the surface and inside of the intelligent response functional layer by stepwise immersion, and then subjected to washing, drying, and winding to obtain the silica gel fragrance line material.

[0061] In some specific embodiments, the raw materials of the silica gel base material can be put into a mixing mill according to the proportion to obtain a uniform mixing rubber; then the mixing rubber is put into a multi-stage extruder to be extruded into a wire blank body with a porous honeycomb structure; finally, the wire blank body is subjected to segmented vulcanization, and then subjected to surface hydrophilic treatment to obtain the silica gel base material.

[0062] In some specific embodiments, the wavelength range of the ultraviolet light can be 254 nm to 365 nm, and the irradiation intensity can be 30 mW / cm2 .

[0063] In some specific embodiments, the temperature of the in-situ polymerization can be 50-60℃, and the time can be 2-4 hours.

[0064] In some specific embodiments, after the composite fragrance system of the microemulsion is loaded on the surface and inside of the smart response functional layer through stepwise impregnation, it can be washed with deionized water, vacuum dried at 60℃ for 4 hours, and wound to obtain a silica gel fragrance line material.

[0065] According to embodiments of the present disclosure, first, a porous honeycomb structure hydrophilic silica gel base material conducive to fragrance loading is prepared through processes such as mixing of specific components, segmented vulcanization, and hydrophilic treatment, while ensuring excellent mechanical properties of the silica gel. Then, a grafted copolymer layer mainly composed of poly(acrylic acid-co-vinyl pyrrolidone) is constructed on the surface of the hydrophilic silica gel base material through UV light-induced graft polymerization under mild conditions, i.e., an interface enhancement layer, effectively improving the interlayer bonding force of the fragrance line material. Then, the temperature-sensitive and shape memory material is in-situ polymerized, directly forming a smart response functional layer with uniform structure and sensitive response on the interface layer, achieving precise control of fragrance release. Finally, by utilizing the nanometer characteristics of the microemulsion and the temperature-sensitive characteristics of the functional layer, deep penetration and stable loading of fragrance components in the network on the surface and inside of the smart response functional layer are achieved through a stepwise impregnation process, ensuring the uniformity and durability of the release. The process is closely connected and highly controllable, and the synergy of each step ensures significant improvement in the uniformity, durability, and stability of the final product in terms of fragrance release, with good prospects for industrial application.

[0066] According to embodiments of the present disclosure, the segmented vulcanization specifically includes the following three-stage vulcanization.

[0067] First-stage vulcanization: 2-4 minutes at 120-150℃, triggering the preliminary decomposition of the crosslinking agent under relatively mild conditions to form a preliminary crosslinking network, preventing structural collapse during subsequent high-temperature vulcanization.

[0068] Second-stage vulcanization: 30-60 minutes at 180-220℃, promoting the decomposition and network densification of the crosslinking agent at a higher temperature to ensure that the base material obtains the required mechanical strength and elasticity.

[0069] Third-stage vulcanization: 1-2 hours at 230-250℃, through high-temperature and long-time vulcanization treatment, eliminating residual volatile components, driving out internal stress, and further stabilizing the crosslinking network, significantly improving the long-term performance of the base material.

[0070] The temperature rising rate between each stage of vulcanization is 2-5°C / min, and a slow program temperature rising is used between each stage to avoid temperature sudden change to cause micro-cracks or hole structure damage in the substrate, and to ensure the integrity and uniformity of the porous honeycomb structure.

[0071] According to an embodiment of the present disclosure, the surface hydrophilic treatment includes plasma treatment. The plasma treatment includes: placing the silica gel wire in a plasma generating device, inputting oxygen or argon, and treating for 2-4 minutes under the conditions of a power of 200-400 W and a chamber pressure of 50-100 Pa to obtain the silica gel substrate.

[0072] Optionally, the power may be, for example, 200 W, 250 W, 300 W, 350 W, 400 W, etc.; the chamber pressure may be, for example, 50 Pa, 60 Pa, 70 Pa, 80 Pa, 90 Pa, 100 Pa, etc.; and the treatment time may be, for example, 2 minutes, 3 minutes, 4 minutes, etc.

[0073] The treatment process can effectively remove organic pollutants on the surface of the silica gel wire by high-energy plasma bombardment, and can make the molecular chains on the surface break, generate active free radicals and polar groups (such as hydroxyl groups, carboxyl groups, etc.), thereby significantly improving the surface energy and obtaining an activated silica gel substrate. Appropriate treatment conditions can effectively activate the surface of the silica gel while avoiding surface etching damage caused by excessive energy or excessive treatment time. The activated surface provides sufficient active sites for subsequent interfacial reinforcement layer graft polymerization, further ensuring the firmness of the interlayer bonding.

[0074] According to an embodiment of the present disclosure, the preparation method of the microemulsion includes steps (a)-(d).

[0075] Step (a): 5-12 parts by weight of an aroma core, 1.5-7.2 parts by weight of a stable layer, and 2-12 parts by weight of a protective layer are stirred and mixed to dissolve at 50-65°C to obtain an oil phase mixture.

[0076] Step (b): 3-8 parts by weight of an emulsifier and 60-100 parts by weight of deionized water are stirred and mixed to dissolve at 50-65°C to obtain an aqueous solution.

[0077] Step (c): The oil phase mixture is gradually added to the aqueous solution under a shear speed of 8000-12000 rpm, and emulsified for 5-10 minutes to form a coarse emulsion.

[0078] Step (d): The coarse emulsion is transferred into a high-pressure homogenizer, and is treated for 2-4 times under a pressure of 40-80 MPa to obtain a microemulsion.

[0079] Optionally, the aroma core may be, for example, 5, 7, 9, 10, 12 parts, etc.; the stabilizing layer may be, for example, 1.5 parts, 2 parts, 4 parts, 6 parts, 7 parts, 7.2 parts, etc.; the protective layer may be, for example, 2 parts, 5 parts, 7 parts, 9 parts, 10 parts, 12 parts, etc.; the emulsifier may be, for example, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, etc.; and the deionized water may be, for example, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, etc.

[0080] Through the combined process of step-by-step emulsification and high-pressure homogenization, the oil phase components can be efficiently dispersed in the water phase, and with the aid of strong mechanical shearing and impact, the emulsion droplets are further broken and homogenized, ultimately obtaining a nanoscale microemulsion with uniform particle size distribution and excellent stability, which provides an ideal carrier system for the subsequent efficient loading and controllable release of aroma components.

[0081] According to an embodiment of the present disclosure, the step-by-step impregnation includes the following three stages.

[0082] The first stage: impregnate the silica gel wire material with the completed intelligent response functional layer in the microemulsion at a temperature of 25-30°C for 1-3 hours;

[0083] The second stage: warm the microemulsion to 35-40°C at a rate of 0.3-0.8°C / min, and keep the temperature for 30-50 minutes of impregnation;

[0084] The third stage: continue to warm the microemulsion to 45-50°C at a rate of 0.1-0.3°C / min, and keep the temperature for 1-2 hours of impregnation.

[0085] According to an embodiment of the present disclosure, the first stage of the step-by-step impregnation is low-temperature penetration, so that the intelligent response functional layer polymer network is in a swollen state, and the aroma components in the microemulsion can diffuse and penetrate into the network; the second stage is preliminary fixation, the network of the intelligent response functional layer begins to shrink slightly, and produces a preliminary coating effect on the penetrated aroma molecules, achieving preliminary fixation; the third stage is intelligent encapsulation, triggering the phase change of the intelligent response functional layer, and the network structure shrinks significantly, thereby tightly encapsulating the loaded aroma molecules in the network, completing the final fixation. The step-by-step impregnation process fully utilizes the temperature response characteristics of the intelligent response functional layer, and realizes the step-by-step progressive loading process of aroma molecules from penetration to fixation to encapsulation through programmed temperature rise, ensuring high loading rate and long-acting slow-release performance of the aroma.

[0086] According to an embodiment of another aspect of the present disclosure, an application of the above-mentioned silica gel aroma wire material in a filter rod fixture for cigarettes is proposed.

[0087] According to the embodiments of the present disclosure, the silica gel aroma thread material of the present disclosure is applied to a filter rod for cigarettes, and the intelligent response function layer dynamically adjusts the aroma diffusion channel by sensing the temperature of the smoke, effectively overcoming the defects of traditional aroma threads that are dense at the beginning and weak at the end, and can realize precise controllable and long-acting stable aroma release; the high-temperature resistance of the silica gel base material and the multiple coating structure of the composite aroma system jointly guarantee the stability of the aroma during the processing and storage process, significantly prolonging the action time; at the same time, the good mechanical properties of the silica gel aroma thread material ensure its form stability during the filter rod forming process, providing a reliable solution for improving the sensory quality of cigarette products.

[0088] In order to make the purpose, technical solutions and advantages of the present disclosure clearer and more apparent, the present disclosure will be further described in detail below in combination with specific embodiments. If no specific technology or condition is specified in the embodiments, it is a conventional method, which can be carried out according to the technology or condition described in the literature in the art or according to the product instruction. It should be noted that the methods provided by the present disclosure are conventional methods unless otherwise specified, and the reactants and reagents can be obtained from public commercial channels unless otherwise specified.

[0089] In the specific embodiments of the present disclosure, the sources of some main raw materials are briefly described as follows.

[0090] Methyl vinyl silicone rubber raw rubber: 110 type methyl vinyl silicone rubber (raw rubber) of Inner Mongolia Hengye Chemical Co., Ltd., molecular weight range 45-70 x 10 4 , vinyl content 0.03~0.24%.

[0091] Hydrophobic fumed white carbon black: Fujian Yuanxiang New Material Co., Ltd.

[0092] Hexamethyldisilazane: Shandong Luoheng Chemical Product Co., Ltd., CAS 999-97-3.

[0093] γ-aminopropyltriethoxysilane: Jiangxi Hongbai New Material Co., Ltd., industrial grade KH-550.

[0094] 2,5-Dimethyl-2,5-di-tert-butylperoxyhexane: AkzoNobel Peroxide (Ningbo) Co., Ltd.

[0095] Iron oxide red: Hunan Sanhuan Pigment Co., Ltd.

[0096] Acrylic acid: National Pharmaceutical Group Chemical Reagent Co., Ltd., CAS 79-10-7.

[0097] N-vinylpyrrolidone: Shanghai Aladdin Biochemical Technology Co., Ltd., purity ≥ 99%, CAS 88-12-0.

[0098] N-Isopropylacrylamide: Shandong Yinglang Chemical Co., Ltd., CAS 25189-55-3.

[0099] Polycaprolactone-polyurethane block copolymer: Covestro (China) Co., Ltd., model DL1000.

[0100] Mesoporous silica nanospheres: Jin Sanjiang (Zhaoqing) Silicon Material Co., Ltd., model C253.

[0101] N,N'-Methylenebisacrylamide: Sinopharm Chemical Reagent Co., Ltd., CAS 110-26-9.

[0102] Thermochromic microcapsules: Shenzhen Fantasy Color-Changing Technology Co., Ltd.

[0103] Menthol: Nantong Feiyu Biological Technology Co., Ltd., natural menthol, CAS 89-78-1.

[0104] Lecithin: Shanghai Yuan Ye Biological Technology Co., Ltd., soybean lecithin, CAS 8002-43-5.

[0105] Hydroxypropyl-β-cyclodextrin: Shandong Binzhou Zhiyuan Biological Technology Co., Ltd., pharmaceutical excipient grade, CAS 128446-35-5.

[0106] Tween 80: Nantong Fengyuan Chemical Co., Ltd., meets food grade standards, CAS 9005-65-6.

[0107] n-Tetradecane: Shanghai Aladdin Biochemical Technology Co., Ltd., CAS 629-59-4.

[0108] Example 1:

[0109] The present embodiment provides a long-acting slow-release silica gel fragrance material, which is composed of a silica gel base material, an interface enhancement layer, an intelligent response functional layer, and a composite fragrance system in a dry base mass ratio of 100:5:15:20.

[0110] The preparation process of the silica gel fragrance material is as follows.

[0111] (1) Preparation of silica gel base material

[0112] Take 100 parts of methyl vinyl silicone rubber raw rubber, 25 parts of hydrophobic fumed silica with a specific surface area of 300 m 2 / g, 1.5 parts of 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane, 4 parts of red iron oxide, and 3 parts of surface treatment agent, wherein the surface treatment agent is a compound composed of hexamethyl disilazane and γ-aminopropyl triethoxysilane in a mass ratio of 4:1.

[0113] The above components were put into an internal mixer and mixed at 80°C and a rotor speed of 60 rpm for 30 minutes to form a uniform mixed rubber. The mixed rubber was then put into a multi-stage extruder and extruded at 120°C and a die pressure of 15 MPa to obtain a wire blank with a porous honeycomb structure.

[0114] The wire blank was then subjected to segmented vulcanization: the first segment was vulcanized at 150°C for 4 minutes, the second segment was vulcanized at 220°C for 60 minutes, and the third segment was vulcanized at 250°C for 2 hours, with a temperature rise rate of 5°C / min between each segment. Finally, the vulcanized wire blank was subjected to plasma pretreatment at a power of 400W for 4 minutes, an oxygen flow rate of 40 standard milliliters per minute, and a chamber pressure of 100Pa to obtain a hydrophilic silica gel base material. The cross-section of the silica gel base material was a porous honeycomb structure with a porosity of 40%, a pore size of 200μm, and a microchannel width of 20μm.

[0115] (2) Construction of the interface enhancement layer

[0116] The silica gel base material was immersed in 50 parts of deionized water containing 3 parts of acrylic acid and 3 parts of N-vinyl pyrrolidone, and subjected to graft polymerization under ultraviolet light irradiation for 3 hours at 60°C in an oxygen-free environment. The ultraviolet light had a wavelength of 365 nm and an irradiation intensity of 30mW / cm 2 , forming a graft copolymer layer mainly composed of poly(acrylic acid-co-vinyl pyrrolidone).

[0117] (3) Preparation of the intelligent response functional layer

[0118] N-isopropyl acrylamide 8 parts, polycaprolactone-polyurethane block copolymer 3 parts, mesoporous silica nanospheres loaded with n-tetradecane 0.5 parts (n-tetradecane loading capacity 40%), N,N'-methylene bisacrylamide 0.064 parts, deionized water 150 parts, thermochromic microcapsules 0.3 parts (particle size 10 microns, color change temperature 50°C). The above components were mixed and then subjected to in-situ copolymerization on the interface enhancement layer to form an intelligent response functional layer, obtaining a silica gel wire with the intelligent response functional layer constructed.

[0119] (4) Preparation of the composite aroma system

[0120] Menthol 12 parts, lecithin 7.2 parts, hydroxypropyl-β-cyclodextrin 12 parts were mixed at 65℃ under stirring until dissolved to obtain an oil phase mixture; 8 parts of emulsifier Tween 80 and 100 parts of deionized water were mixed at 65℃ under stirring until dissolved to obtain an aqueous phase solution; under high-speed shearing at 12000 rpm, the oil phase mixture was slowly added to the aqueous phase mixture, emulsified for 10 minutes to form a coarse emulsion; then the coarse emulsion was transferred into a high-pressure homogenizer, and was treated under 80 MPa pressure for 4 cycles to obtain a microemulsion with a triple-coated structure of composite aroma system with a droplet particle size of 200 nm.

[0121] (5) Stepwise impregnation

[0122] The first stage was to impregnate the silica gel wire material with the completed smart response functional layer in the microemulsion at 30℃ for 3 hours; the second stage was to heat the microemulsion to 40℃ at a heating rate of 0.8℃ / min, and then to impregnate for 50 minutes; the third stage was to heat the microemulsion to 50℃ at a heating rate of 0.3℃ / min, and then to impregnate for 2 hours, so as to load the composite aroma system on the surface and inside of the smart response functional layer.

[0123] Finally, the silica gel aroma wire material was obtained by washing with deionized water and vacuum drying at 60℃ for 4 hours.

[0124] Example 2

[0125] In this embodiment, the same as in Example 1 will not be repeated, and the difference is mainly in the component ratio and process parameters, which are as follows.

[0126] The interface enhancement layer, the smart response functional layer and the composite aroma system of the silica gel base material are in a dry mass ratio of 100:1:5:8.

[0127] (1) Preparation of silica gel base material

[0128] The specific surface area of the hydrophobic fumed white carbon black is 150 m 2 / g, 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane 0.8 parts, iron oxide red 2 parts, and surface treatment agent 1 part, wherein the surface treatment agent is a complex of hexamethyl disilazane and γ-aminopropyl triethoxysilane in a mass ratio of 2:1.

[0129] The mixing was carried out at 50℃ and a rotor speed of 20 rpm for 10 minutes to form a uniform mixing rubber. Then the mixing rubber was put into a multi-stage extruder and extruded into a porous honeycomb structure at 80℃ and a die pressure of 5 MPa.

[0130] Subsequently, the wire blank was segmented vulcanized: the first segment was vulcanized at 120°C for 2 minutes, the second segment was vulcanized at 180°C for 30 minutes, and the third segment was vulcanized at 230°C for 1 hour, and the temperature rise rate between each segment was 2°C / min. Finally, the vulcanized wire blank was subjected to plasma pretreatment, with a treatment power of 200W, a treatment time of 2 minutes, an oxygen flow rate of 20 standard milliliters / min, and a chamber pressure of 50Pa, to obtain a hydrophilic silica gel base material. The cross section of the silica gel base material was a porous honeycomb structure, with a porosity of 20%, a pore size of 50μm, and a microchannel width of 5μm between the pores.

[0131] (2) Construction of the interface enhancement layer

[0132] The silica gel base material was immersed in 100 parts of deionized water containing 1 part of acrylic acid and 0.5 parts of N-vinyl pyrrolidone, and subjected to graft polymerization under ultraviolet light irradiation for 1 hour at 40°C in an oxygen-free environment, with an ultraviolet light wavelength of 254 nm and an irradiation intensity of 10 mW / cm 2 , to form a grafted copolymer layer mainly composed of poly(acrylic acid-co-vinyl pyrrolidone).

[0133] (3) Preparation of the intelligent response functional layer

[0134] N-isopropyl acrylamide 5 parts, polycaprolactone-polyurethane block copolymer 1 part, mesoporous silica nanospheres loaded with n-tetradecane 0.1 part (n-tetradecane loading capacity 20%), N,N'-methylene bisacrylamide 0.012 parts, deionized water 80 parts, and thermochromic microcapsules 0.05 parts (particle size 1 micron, color change temperature 40°C) were mixed, and the intelligent response functional layer was formed on the interface enhancement layer by in-situ copolymerization, to obtain a silica gel wire with the intelligent response functional layer constructed.

[0135] (4) Preparation of the composite aroma system

[0136] Menthol 5 parts, lecithin 1.5 parts, and hydroxypropyl-β-cyclodextrin 2 parts were stirred and mixed to dissolve at 65°C to obtain an oil phase mixture; 3 parts of the emulsifier Tween 80 and 60 parts of deionized water were stirred and mixed to dissolve at 65°C to obtain an aqueous phase solution; the oil phase mixture was slowly added to the aqueous phase mixture under high-speed shearing at 8000 rpm, and emulsified for 5 minutes to form a coarse emulsion; then the coarse emulsion was transferred to a high-pressure homogenizer, and treated twice at a pressure of 40MPa to obtain a microemulsion with a triple-coated structure of the composite aroma system, with a droplet particle size of 50nm.

[0137] (5) Stepwise impregnation

[0138] The first stage is to immerse the silica gel wire material with the constructed intelligent response functional layer into the microemulsion at 25℃ for 1 hour; the second stage is to heat the microemulsion to 35℃ at a heating rate of 0.3℃ / min, and keep the temperature for 30 min; the third stage is to heat the microemulsion to 45℃ at a heating rate of 0.1℃ / min, and keep the temperature for 1 hour, so as to load the composite aroma system on the surface and inside of the intelligent response functional layer.

[0139] Example 3

[0140] In this embodiment, the same as in Example 1 will not be repeated, and the difference is mainly in the allocation ratio of each component and the process parameters, which are as follows.

[0141] The silica gel base material interface enhancement layer, the intelligent response functional layer and the composite aroma system are in a dry base mass ratio of 100:3:10:14.

[0142] (1) Preparation of silica gel base material

[0143] The specific surface area of the silica gel base material is 200 m 2 / g of hydrophobic fumed white carbon black 20 parts, 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane 1.2 parts, iron oxide red 3 parts, and surface treatment agent 2 parts, wherein the surface treatment agent is a complex of hexamethyldisilazane and γ-aminopropyl triethoxysilane in a mass ratio of 3:1.

[0144] Mixing at 60℃ and rotor speed of 40 revolutions / minute for 20 minutes to form a uniform mixing rubber. Then the mixing rubber is put into a multi-stage extruder, and extruded into a wire blank at 100℃ and a die pressure of 10 MPa, to obtain a wire blank with a porous honeycomb structure.

[0145] Then the wire blank is subjected to segmented vulcanization: the first stage of vulcanization is carried out at 130℃ for 3 minutes, the second stage of vulcanization is carried out at 200℃ for 45 minutes, and the third stage of vulcanization is carried out at 240℃ for 1.5 hours, and the temperature rising rate between each stage of vulcanization is 3℃ / min. Finally, the vulcanized wire blank is subjected to plasma pretreatment, with a treatment power of 300 W, a treatment time of 3 minutes, an oxygen flow of 30 standard milliliters / minute, and a chamber pressure of 80 Pa, to obtain a hydrophilic silica gel base material. The cross section of the silica gel base material is a porous honeycomb structure, with a porosity of 30%, a pore size of 100 μm, and a microchannel width between the pores of 10 μm.

[0146] (2) Construction of interface enhancement layer

[0147] The silica gel base material is immersed in 80 parts of deionized water containing 2 parts of acrylic acid and 1.5 parts of N-vinyl pyrrolidone, and subjected to graft polymerization reaction under ultraviolet light irradiation for 2 hours in an anaerobic environment at 50℃, with an ultraviolet light wavelength of 300 nm and an irradiation intensity of 20 mW / cm 2, forming a graft copolymer layer mainly of poly(acrylic acid-co-vinyl pyrrolidone).

[0148] (3) Preparation of the intelligent response function layer

[0149] Take N-isopropyl acrylamide 6 parts, polycaprolactone-polyurethane block copolymer 2 parts, mesoporous silica nanospheres loaded with n-tetradecane 0.3 parts (n-tetradecane loading capacity is 30%), N,N'-methylene bisacrylamide 0.038 parts, deionized water 120 parts, and thermochromic microcapsules 0.2 parts (particle size 5 microns, color change temperature 45℃). After mixing the above components, an intelligent response function layer is formed on the interface enhancement layer by in-situ copolymerization, and an intelligent response function layer constructed silica gel wire is obtained. The polymerization reaction temperature is 60℃, and the reaction lasts for 4 hours.

[0150] (4) Preparation of the composite aroma system

[0151] Mix menthol 8 parts, lecithin 4 parts, and hydroxypropyl-β-cyclodextrin 7 parts at 65℃ under stirring until dissolved to obtain an oil phase mixture; mix 6 parts of emulsifier Tween 80 and 80 parts of deionized water at 65℃ under stirring until dissolved to obtain an aqueous phase solution; under high-speed shearing at 10000 rpm, slowly add the oil phase mixture into the aqueous phase mixture, emulsify for 8 minutes to form a coarse emulsion; then transfer the coarse emulsion into a high-pressure homogenizer, and process it under 60 MPa pressure for 3 cycles to obtain a microemulsion with a triple-coated structure of the composite aroma system with a droplet particle size of 100 nm.

[0152] (5) Stepwise impregnation

[0153] In the first stage, the silica gel wire with the intelligent response function layer constructed is immersed in the microemulsion at 28℃ for 2 hours; in the second stage, the microemulsion is heated to 38℃ at a heating rate of 0.5℃ / min, and the immersion is kept for 40 minutes; in the third stage, the microemulsion is heated to 48℃ at a heating rate of 0.2℃ / min, and the immersion is kept for 1.5 hours, and the composite aroma system is loaded on the surface and inside of the intelligent response function layer.

[0154] Comparative Example 1

[0155] In this comparative example, the same as in Example 1 is not repeated, and the difference is that the construction step of the interface enhancement layer is omitted, and the intelligent response function layer is directly constructed on the silica gel substrate.

[0156] Comparative Example 2

[0157] In this comparative example, the same as in Example 1 is not repeated, and the difference is that the traditional one-step vulcanization process is used instead of the segmented vulcanization process, and the vulcanization conditions are 170℃ for 10 minutes.

[0158] Comparative Example 3

[0159] In the present comparative example, the same as in Example 1 is not repeated, and the difference is that no n-tetradecane-loaded mesoporous silica nanospheres and thermochromic microcapsules are added in the smart response functional layer.

[0160] Comparative Example 4

[0161] In the present comparative example, the same as in Example 1 is not repeated, and the difference is that a simple physical mixture of aroma components is used instead of a triple-coated composite aroma system, and the aroma components are directly mixed with the substrate.

[0162] Comparative Example 5

[0163] In the present comparative example, the same as in Example 1 is not repeated, and the difference is that the step-by-step impregnation process is replaced by a single temperature impregnation, which is impregnated at 25°C for 12 hours.

[0164] Comparative Example 6

[0165] In the present comparative example, the same as in Example 1 is not repeated, and the difference is that the silica gel substrate does not have a porous honeycomb structure, and a solid silica gel wire is used.

[0166] Performance test results and analysis

[0167] The following test methods were used to evaluate the performance of the samples prepared in the examples and comparative examples: the aroma release uniformity index was determined according to GB / T 23203-2008 method, defined as the ratio of the aroma release amount of the 6th-10th mouth to the 1st-5th mouth; the aroma persistence index was determined according to GB / T 23203-2008 method, defined as the ratio of the aroma release amount of the 11th-15th mouth to the 1st-5th mouth; the aroma retention rate was determined according to GB / T 1607-2001 method, the percentage of aroma content after storing the sample at 25°C and 60% relative humidity for 6 months was determined compared with the initial content; the interlayer bonding strength was determined according to GB / T 2790-1995 method; the thermal stability was determined by a thermal gravimetric analyzer under nitrogen atmosphere from room temperature to 600°C to determine the initial decomposition temperature. The test results are shown in Table 1.

[0168] Table 1

[0169]

[0170] As can be seen from Table 1, the three embodiments are significantly better than the comparative examples in various performance indicators. Example 1 adopts a relatively extreme combination of parameters and performs best in terms of aroma release uniformity and persistence, thanks to its larger specific surface area and sufficient interfacial bonding. Example 2, although some parameters are relatively conservative, such as the use of silica gel substrate, the amount of components in the intelligent response functional layer, and the parameters in the segmented vulcanization and stepwise impregnation process, still maintains good overall performance, indicating that the present disclosure can achieve the expected effect within a wide range of parameters. In Example 3, the parameters are intermediate values, and a good balance is achieved in various performance indicators.

[0171] Comparative Example 1, due to the omission of the interfacial enhancement layer, results in a significant decrease in interlayer bonding strength, which in turn affects the stable release and long-term retention of aroma. This result proves the key role of the interfacial enhancement layer in solving the problem of hydrophobicity of the silica gel surface and the combination of the functional layer. Comparative Example 2 uses a traditional vulcanization process, and its thermal stability and aroma retention rate are significantly reduced, indicating that the segmented vulcanization process is crucial for forming a stable three-dimensional network structure. Comparative Example 3 does not add mesoporous silica nanospheres and thermochromic microcapsules, and its aroma controlled release performance and thermal stability decrease, proving that these functional components have a positive effect on improving product performance.

[0172] Comparative Example 4 uses a simple physical mixing of the aroma system, and its aroma release uniformity and persistence are significantly reduced, indicating that the triple-coated structure plays an irreplaceable role in protecting aroma components and controlling release. Comparative Example 5 uses a single temperature impregnation process, and its aroma loading effect is significantly inferior to the stepwise impregnation process, proving that the programmed temperature process is crucial for precise loading of aroma molecules. Comparative Example 6 uses a solid silica gel substrate, and due to its significantly reduced specific surface area, the aroma loading is insufficient, affecting the product's persistence.

[0173] In summary, the present disclosure successfully solves the technical problems of traditional fragrance line materials in aroma release uniformity, persistence, and stability through the design of the porous structure of the silica gel substrate, the construction of the interfacial enhancement layer, the optimization of the intelligent response functional layer, and the triple-coated structure of the composite aroma system, combined with the segmented vulcanization and stepwise impregnation processes. The various technical features exhibit significant synergistic effects, and the absence or change of any key feature will result in a significant decrease in product performance.

[0174] The silica gel fragrance line material provided by the present disclosure and its preparation method and application have at least one or part of the following beneficial effects compared to traditional silica gel fragrance line materials:

[0175] (1) The present disclosure selects methyl vinyl silicone rubber to prepare a silica gel base material, wherein the three-dimensional network structure provides stable physical support for aroma loading. Through a precisely controlled segmented vulcanization process, a porous honeycomb structure with a specific porosity and pore size distribution is formed inside the silica gel base material. This structure not only significantly increases the specific surface area of the aroma load, but also provides an ideal substrate for the construction of subsequent functional layers.

[0176] (2) To address the problem of strong hydrophobicity of the silica gel material surface and poor binding force with polar substances, active sites are generated on the surface of the vulcanized silica gel wire blank through hydrophilic treatment, introducing polar groups such as hydroxyl and carboxyl groups. Subsequently, a copolymer film is formed through graft polymerization, constructing an interface enhancement layer. This design realizes a gradient transition from the conventional inert silica gel surface to a hydrophilic functional layer, effectively solving the technical problem of weak interlayer bonding force and laying a foundation for the firm adhesion of subsequent functional layers.

[0177] (3) The present disclosure constructs a three-dimensional network structure with temperature response characteristics by synergistically polymerizing materials with temperature sensitivity and materials with shape memory characteristics. The structure of the intelligent response functional layer undergoes reversible volume changes when the ambient temperature reaches the phase transition temperature, thereby achieving intelligent control of the aroma release rate. In addition, the introduction of mesoporous silica nanospheres loaded with phase change modifiers further refines the response behavior of the network, making the aroma release curve more stable.

[0178] (4) In the design of the aroma system, the present disclosure adopts a multiple protection strategy. By combining the aroma core, the stabilization layer, and the protection layer in a specific ratio, a stable triple-coated structure is formed. The stabilization layer can form a dense arrangement at the oil-water interface, effectively blocking the penetration of oxygen molecules; the protection layer further improves the stability of the aroma components through molecular encapsulation. This multi-level protection mechanism significantly improves the retention rate of aroma components during storage.

[0179] (5) The microemulsification process of the present disclosure ensures that the aroma system can be uniformly dispersed and stably exist. Through a combination of stepwise emulsification and high-pressure homogenization, a microemulsion with uniform particle size distribution is successfully prepared. This uniformity at the microscale creates favorable conditions for the subsequent stepwise impregnation process, allowing the aroma components to fully penetrate into various parts of the functional layer network.

[0180] (6) The design of the stepwise impregnation process of the present disclosure fully utilizes the temperature-sensitive properties of the functional layer. By precisely controlling the heating rate and holding time, the gradual process of aroma component penetration from the initial stage to the final encapsulation is achieved. During programmed heating, the gradual shrinkage of the functional layer network forms a dynamic balance with the penetration and diffusion of the aroma microemulsion, ultimately achieving stable immobilization of the aroma components at the molecular level.

[0181] (7) The introduction of thermochromic microcapsules provides an intuitive quality indication function for the product. When the ambient temperature reaches the set value, the microcapsules undergo reversible color change, which not only provides visual feedback for consumers, but also realizes real-time monitoring of the product usage state. This design increases the additional use value while maintaining the basic function of the product.

[0182] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A silicone thread material, characterized by The silica gel fragrance thread material comprises, from inside to outside, a silica gel base material, an interface reinforcing layer, a smart response functional layer, and a composite fragrance system loaded on the surface and inside of the smart response functional layer, and the dry weight ratio of the silica gel base material, the interface reinforcing layer, the smart response functional layer, and the composite fragrance system is 100:(1-5):(5-15):(8-20), wherein The silica gel base material is a silica gel wire material after surface hydrophilic treatment, and the silica gel wire material has a porous honeycomb structure. The interface reinforcing layer is a copolymer film formed by graft polymerization of acrylic acid and N-vinyl pyrrolidone on the surface of the silica gel base material. The smart response functional layer is a functional layer formed on the interface reinforcing layer by in-situ polymerization, comprising a copolymer of a temperature-sensitive polymer and a shape memory polymer, and mesoporous silica nanospheres loaded with a phase change regulator, and the phase transition temperature of the smart response functional layer is 35-45℃. The composite fragrance system is a microemulsion containing a fragrance core.

2. The silica gel fragrance thread material according to claim 1, wherein The silicone rubber base material comprises, in parts by weight, 100 parts of methyl vinyl silicone rubber raw rubber, 15-25 parts of hydrophobic reinforcing agent, 0.8-1.5 parts of cross-linking agent, and 2-4 parts of colorant, the specific surface area of the hydrophobic reinforcing agent being 150-300 m 2 / g. The hydrophobic reinforcing agent includes any one of hydrophobic fumed silica, hydrophobic precipitated silica, and silica powder treated with a silane coupling agent, The crosslinking agent includes any one of 2,5-dimethyl-2,5-di-tert-butyl peroxide, dicumyl peroxide, and bis-(tert-butyl peroxyisopropyl) benzene; The colorant includes any one of red iron oxide, yellow iron oxide, and carbon black, The silica gel base material has a porosity of 20%-40%, a pore size of 50-200μm, and microchannels with a width of 5-20μm between the pores.

3. The silica gel fragrance thread material according to claim 2, wherein The silica gel base material further includes 1-3 parts of a surface treatment agent, and the surface treatment agent is a compound of hexamethyldisilazane and γ-aminopropyl triethoxysilane in a weight ratio of 2-4:

1.

4. The silica gel fragrance thread material according to claim 1, wherein The weight ratio of acrylic acid to N-vinyl pyrrolidone in the composition of the interface reinforcing layer is 6:1 to 1:

3.

5. The silica gel fragrance thread material according to claim 1, wherein The smart response functional layer is formed by in-situ copolymerization of 5-8 parts of a temperature-sensitive polymer, 1-3 parts of a shape memory polymer, 0.1-0.5 parts of mesoporous silica nanospheres loaded with a phase change regulator, 0.012-0.064 parts of a crosslinking agent, and 80-150 parts of deionized water, in terms of weight fraction, The temperature-sensitive polymer includes N-isopropyl acrylamide; The shape memory polymer includes a polycaprolactone-polyurethane block copolymer; The crosslinking agent includes N,N'-methylenebisacrylamide; The phase change regulator includes n-tetradecane, and the loading amount is 20%-40% of the weight of the mesoporous silica nanospheres.

6. The silica gel fragrance thread material according to claim 5, wherein The smart response functional layer further includes 0.05-0.3 parts of thermochromic microcapsules, The thermochromic microcapsules have a particle size of 1-10μm, The shell material of the thermochromic microcapsule is a gelatin-arabic gum compound, the core material is a crystal violet lactone-bisphenol A color developing system, and the color changing temperature is 40-50 DEG C.

7. The silicone thread material of claim 1, wherein, The microemulsion droplet size is 50-200 nm, and is prepared by mixing a fragrance core, a stabilizing layer, a protective layer, and an emulsifier, The fragrance core includes any one of menthol, tobacco extract essence, coffee essence, cocoa essence, and fruit essence; The stabilizing layer includes any one of lecithin, stearic acid monoglyceride, and sorbitan monooleate; The protective layer includes any one of hydroxypropyl-beta-cyclodextrin, methyl-beta-cyclodextrin, and chitosan; The emulsifier includes any one of Tween 80, polyoxyethylene sorbitan monostearate, and sorbitan monolaurate.

8. A method of producing the silicone thread material according to any one of claims 1 to 7, characterized by, The preparation method includes: According to weight fractions, methyl vinyl silicone rubber raw rubber, hydrophobic reinforcing agent, crosslinking agent, colorant are mixed, extruded and segmented vulcanized, and then the silicone base material is obtained after surface hydrophilic treatment; The silicone base material is immersed in an aqueous solution containing acrylic acid and N-vinyl pyrrolidone monomers, and a grafting polymerization reaction occurs under the irradiation of ultraviolet light for 1-3 hours in an anaerobic environment at 40-60 DEG C, forming an interfacial reinforcing layer; On the interfacial reinforcing layer, a solution containing a temperature-sensitive polymer, a shape memory polymer, mesoporous silica nanospheres loaded with a phase change regulator, and a crosslinking agent is formed into an intelligent response functional layer by in-situ polymerization; The composite fragrance system of the microemulsion is loaded on the surface and inside of the intelligent response functional layer by stepwise immersion, and the silicone thread material is obtained after washing, drying, and winding.

9. The preparation method of claim 8, wherein, The segmented vulcanization specifically includes: The first segment vulcanization is performed at 120-150 DEG C for 2-4 minutes; The second segment vulcanization is performed at 180-220 DEG C for 30-60 minutes; The third segment vulcanization is performed at 230-250 DEG C for 1-2 hours, wherein, The temperature rising rate between each segment vulcanization is 2-5 DEG C / minute, The surface hydrophilic treatment includes plasma treatment, and the plasma treatment includes: The silicone thread material is placed in a plasma generating device, oxygen or argon is introduced, and the treatment is performed at a power of 200-400 W and a chamber pressure of 50-100 Pa for 2-4 minutes to obtain the silicone base material, The preparation method of the microemulsion includes: The oil phase mixture is obtained by stirring and mixing 5-12 parts of the fragrance core, 1.5-7.2 parts of the stabilizing layer, and 2-12 parts of the protective layer at 50-65 DEG C until dissolution; The water phase solution is obtained by stirring and mixing 3-8 parts of the emulsifier and 60-100 parts of deionized water at 50-65 DEG C until dissolution; The oil phase mixture is gradually added to the water phase solution under a shear speed of 8000-12000 rpm, emulsified for 5-10 minutes to form a coarse emulsion; The crude emulsion is transferred into a high-pressure homogenizer, and is treated by circulation for 2-4 times under a pressure of 40-80 MPa to obtain the microemulsion, The step-by-step impregnation comprises: impregnating the silica gel wire material with the completed intelligent response functional layer in the microemulsion at a temperature of 25-30 ℃ for 1-3 hours; heating the microemulsion to 35-40 ℃ at a rate of 0.3-0.8 ℃ / min, and incubating for 30-50 min; continuously heating the microemulsion to 45-50 ℃ at a rate of 0.1-0.3 ℃ / min, and incubating for 1-2 hours.

10. Use of the silica gel incense wire material according to any one of claims 1-7 in a filter rod hardware.

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