Double-gel fragrance slow-release carrier and preparation method thereof

Abstract

The invention discloses a double-gel fragrance slow-release carrier and a preparation method thereof, and relates to the technical field of materials, the double-gel fragrance slow-release carrier comprises an aerogel core body and an oil gel coating coated on the surface of the aerogel core body; wherein the aerogel core body is prepared from a polysaccharide-based gel agent, a polyol plasticizer, a pore regulating agent and a flame retardant; the oleogel coating is obtained by mixing a lipophilic gel and a wax-based dispersion medium. The aerogel can be uniformly dispersed and stably loaded with the fragrance component by virtue of the ultrahigh specific surface area and the inner and outer surfaces which can be chemically modified, and the continuous nano pore channels provide a controllable diffusion path, so that the effects of slow release and controlled release are realized. The three-dimensional network formed by the oil gel can accurately regulate and control the volatilization rate of the fragrance component, the long-time linear release of the fragrance component is realized through the synergistic effect of the oil gel and the fragrance component, and the problems of non-uniform release and short duration of a traditional fragrance carrier are solved.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and more specifically, to a dual-gel fragrance sustained-release carrier and its preparation method. Background Technology

[0002] Fragrance sticks, as a fragrance diffusion medium, have been widely used in homes, cars, and commercial spaces in recent years. They work by using capillary action to adsorb liquid fragrance onto the surface of a carrier, which then slowly evaporates into the air, resulting in a long-lasting and even release of the scent.

[0003] There are several main methods for preparing fragrance sticks: First, using natural rattan / wood sticks as raw materials, which are dried, treated with bacteria, and then impregnated with fragrance liquid. This method is low-cost, but the pore distribution is uneven, the porosity is low, and the sustained fragrance release effect is poor. Furthermore, these natural materials have poor flame retardancy and are prone to mold and insect infestation. Second, using modified fibers as raw materials, degreased cotton needs to undergo thiolization treatment, followed by graft copolymerization with eugenol and dihydromyrcenol to produce flexible sticks. While this material significantly improves the adsorption rate, the preparation process is cumbersome and requires the use of toxic sulfur compounds, failing to meet green production requirements. Third, using ultra-high molecular weight polyethylene micropowder as raw material, undergoing amphiphilic modification treatment to produce rigid sticks. This material can save on fragrance usage and has self-cleaning and anti-mold functions, but the cost is high, making it suitable for high-end automotive applications.

[0004] From traditional rattan-stick fragrance carriers to intelligent fragrance carriers, fragrance carriers have evolved from simple carrier materials into microenvironment control devices, showing broader application prospects in fields such as health, marketing, and personalized experiences. Developing new fragrance carriers with high load capacity, controllable cost, and precise controlled release remains an important direction for development in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-gel fragrance sustained-release carrier and its preparation method. This dual-gel fragrance sustained-release carrier has the advantages of strong adsorption capacity, uniform sustained-release effect, long duration, and controllable cost.

[0006] The embodiments of the present invention are implemented as follows: A dual-gel fragrance sustained-release carrier includes an aerogel core and an oleogel coating applied to the surface of the aerogel core. The aerogel core is prepared from polysaccharide-based gelling agents, polyol plasticizers, pore regulators, and flame retardants; the oleogel coating is prepared from a mixture of lipophilic gelling agents and wax-based dispersion media.

[0007] A method for preparing the above-mentioned dual-gel fragrance sustained-release carrier, comprising: S1. Dissolve polysaccharide gelling agent, polyol plasticizer, pore regulator and flame retardant in water to form a sol, pour the sol into a mold to form an aerogel core; S2. The lipophilic gelling agent and wax-based dispersion medium are melt-mixed and coated onto the surface of the aerogel core. After cooling and solidification, an oleogel coating is formed.

[0008] The beneficial effects of the embodiments of the present invention are: This invention provides a dual-gel fragrance sustained-release carrier and its preparation method, comprising an aerogel core and an olegel coating applied to the surface of the aerogel core. The aerogel core is prepared from a polysaccharide-based gelling agent, a polyol plasticizer, a pore-regulating agent, and a flame retardant. The olegel coating is obtained by mixing a lipophilic gelling agent and a wax-based dispersion medium. The aerogel, with its ultra-high specific surface area and chemically modifiable inner and outer surfaces, can uniformly disperse and stably load fragrance components. Its continuous nanopores provide controllable diffusion paths, achieving sustained and controlled release effects. The three-dimensional network formed by the olegel has excellent phase-change heat storage capabilities, absorbing heat from the environment during heating to prevent rapid release of internal fragrance components. This allows for precise control of the evaporation rate of the fragrance components. The synergistic effect of these two components achieves long-term linear release of the fragrance components, solving the problems of uneven release and short duration of traditional fragrance carriers. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 The infrared spectra of the three aerogel cores provided in Experimental Example 1 of this invention; Figure 2 The TG curves of the three aerogel cores provided in Experimental Example 2 of this invention are shown. Figure 3 These are scanning electron microscope images of the three aerogel cores provided in Experimental Example 3 of this invention; Figure 4 The density test results of the three aerogel cores provided in Test Example 4 of this invention; Figure 5 The limiting oxygen index test results of the three aerogel cores provided in Test Example 5 of this invention; Figure 6 These are photographs of the three aerogel cores provided in Test Example 6 of the present invention in contact with oil and water in their uncoated state; Figure 7 The contact angle test results of the three aerogel cores provided in Test Example 6 of the present invention in the uncoated state; Figure 8 These are photographs of the three aerogel cores provided in Test Example 6 of the present invention in contact with oil and water in a coated state; Figure 9 The contact angle test results of the three aerogel cores provided in Test Example 6 of the present invention in the coated state; Figure 10 Comparison of coating and adsorption appearance of the three aerogel cores provided in Experimental Example 7 of the present invention; Figure 11 The test results of the release effect of two fragrance carriers, TPI-B1D1(1:5)-E3P3 and TPI-B1D1(1:5)-E4P3, provided in Test Example 7 of the present invention; Figure 12 The heat flow-temperature curves and volatility test results of the three fragrance carriers provided in Test Example 8 of this invention are shown. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0012] The following is a detailed description of a dual-gel fragrance sustained-release carrier, its preparation method, and its application according to an embodiment of the present invention.

[0013] This invention provides a dual-gel fragrance sustained-release carrier, which includes an aerogel core and an oleogel coating applied to the surface of the aerogel core. The aerogel core is prepared from polysaccharide-based gelling agents, polyol plasticizers, pore regulators, and flame retardants; the oleogel coating is prepared from a mixture of lipophilic gelling agents and wax-based dispersion media.

[0014] Aerogels, with their ultra-high specific surface area and chemically modifiable inner and outer surfaces, can uniformly disperse and stably load fragrance ingredients. Their continuous nanopores provide controllable diffusion pathways, achieving sustained and controlled release effects. The three-dimensional network formed by oleogels can precisely regulate the evaporation rate of fragrance ingredients. The synergistic effect of the two enables long-term linear release of fragrance ingredients, solving the problems of uneven release and short duration of traditional fragrance carriers.

[0015] Furthermore, in the aerogel core, the mass ratio of polysaccharide-based gelling agent, polyol plasticizer, pore regulator, and flame retardant is 1:(0.2~0.5):(1.5~2.5):(2.5~3.5). Within this ratio range, the aerogel exhibits moderate density, uniform pore size, and good adsorption capacity and flame retardant properties.

[0016] Optionally, the polysaccharide-based gelling agent includes at least one of carrageenan, sodium alginate, gelatin, agar, and gellan gum. The polysaccharide-based gelling agent forms a three-dimensional network through hydrogen bonds, creating a porous framework for the aerogel.

[0017] Polyol plasticizers include at least one of glycerol, sorbitol, polyethylene glycol, and propylene glycol; polyol plasticizers are mainly used to improve the toughness of aerogels and prevent structural collapse.

[0018] Pore ​​regulators include at least one of hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, and microcrystalline cellulose. By changing the amount of pore regulator, the density and distribution of pores can be altered, allowing aerogels to be customized.

[0019] Flame retardants include at least one of ammonium polyphosphate, triethyl phosphate, aluminum hypophosphite, expanded graphite, and zinc borate. During thermal decomposition, flame retardants can catalytically form char, creating a dense and stable char layer, thereby achieving a flame-retardant effect.

[0020] Furthermore, the aerogel core also includes 1wt% to 10wt% of bio-based filler, which includes at least one of bamboo powder, straw powder, coffee grounds, and lignin. Introducing bio-based filler can adjust the porosity of the product, and the addition of bio-based materials makes the product more aligned with the "green" development trend, giving the product greater potential for expansion.

[0021] Optionally, the mass ratio of the lipophilic gelling agent to the wax-based dispersion medium is 1:(2~10). Within this ratio range, the viscosity and mechanical strength of the coating can be effectively balanced, ensuring continuous and dense film formation, which is an important factor in ensuring a stable fragrance release rate. The lipophilic gelling agent includes trans-polyisoprene; the wax-based dispersion medium includes at least one of soybean wax, carnauba wax, beeswax, candelilla wax, and paraffin wax. It should be noted that the ratio needs to be adjusted according to the viscosity of the lipophilic gelling agent and the wax-based dispersion medium. If necessary, a mixture of multiple wax-based dispersion media can be used to adjust the viscosity.

[0022] Furthermore, the thickness of the oleogel coating is 0.2~1.0 mm. Within this range, the oleogel coating can better achieve the controlled-release effect. If the thickness of the oleogel coating is too thin, it cannot act as a barrier; if the thickness is too thick, it will hinder the diffusion of the fragrance. A portion of the aerogel core surface is left uncoated with the oleogel coating as a channel area, with an area of ​​50~100 mm². 2 The surface of the aerogel core has pre-reserved channels to serve as channels for fragrance injection, achieving rapid fragrance replenishment and enabling the dual-gel fragrance slow-release carrier to be reused multiple times.

[0023] This invention also provides a method for preparing the above-mentioned dual-gel fragrance sustained-release carrier, comprising: S1. Dissolve polysaccharide gelling agent, polyol plasticizer, pore regulator and flame retardant in water to form a sol, pour the sol into a mold to form an aerogel core; S2. The lipophilic gelling agent and wax-based dispersion medium are melt-mixed and coated onto the surface of the aerogel core. After cooling and solidification, an oleogel coating is formed.

[0024] Further, in step S1, the mixture is stirred and dissolved at 40-60°C to form a sol. During stirring, the polysaccharide-based gelling agent is first dissolved in water and stirred for 0.5-2 hours to dissolve it. Then, the polyol plasticizer is added and stirred for another 0.5-2 hours to mix evenly. Finally, the pore regulator and flame retardant are added and stirred for 1-3 hours to ensure that the components are fully mixed to obtain the sol.

[0025] The sol is poured into a mold and then aged at 0~5℃ to form the aerogel core. Depending on the requirements, the mold can be cylindrical, spherical, cubic, or strip-shaped. The core is then freeze-dried together with the mold at -60~-40℃, and after demolding, the aerogel core is obtained.

[0026] Optionally, in step S2, the melting and mixing temperature is 90~110℃, and the melting time is 3~24h. Within this range, the uniformity of mixing can be ensured. After the mixed and melted raw materials cool, the lipophilic gelling agent will form a three-dimensional network and lock in the wax-based dispersion medium, forming an oleogel coating with a certain mechanical strength. It should be noted that the mixed and melted raw materials can be used immediately or stored after cooling to room temperature for later use. When needed, they only need to be reheated and melted.

[0027] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0028] Example 1

[0029] This embodiment provides a dual-gel fragrance sustained-release carrier, the preparation method of which is as follows: S1. First, dissolve 1 g of carrageenan in deionized water and stir magnetically at 50°C for 1 h until completely dissolved. Then, add 0.3 g of glycerol to the above solution and continue stirring at 50°C for 1 h. Then, mix different masses of hydroxyethyl cellulose (1.5 g, 2 g, 2.5 g) and 3 g of ammonium polyphosphate into the above solution and stir continuously at 50°C for 2 h. Then, pour the stable sol precursor into a cylindrical mold and age at 4°C for 24 h to form a gel. Freeze in the mold with liquid nitrogen and then freeze-dry at -60°C to obtain the aerogel core. For easy differentiation, the materials are named according to the amount of hydroxyethyl cellulose and ammonium polyphosphate used, denoted as E3P3, E4P3, and E5P3, respectively. Wherein, E represents hydroxyethyl cellulose, based on a base amount of 0.5 g; P represents ammonium polyphosphate, based on a base amount of 1 g, and the subscript indicates a multiple of the base amount. For example, E3P3 indicates that the amount of hydroxyethyl cellulose used is three times that of 0.5g, and the amount of ammonium polyphosphate used is three times that of 1g.

[0030] S2. Soybean wax and carnauba wax were melted and mixed at 70°C in a mass ratio of 1:1 to obtain dispersion medium B1D1; then 4 g of trans polyisoprene (TPI) was taken and melted with a corresponding amount of B1D1 sufficient to make the mass ratio of TPI:B1D1 1:5 at 100°C for 6 h to obtain a homogeneous melt; finally, it was cooled to room temperature to allow TPI to form a three-dimensional network and lock B1D1, thus obtaining the TPI-B1D1(1:5) oleogel system.

[0031] S3. Heat the pre-made olegel system to 70°C until it is fully melted and in a fluid state; then, uniformly coat the surface of the aerogel core obtained in step S1 with an olegel coating of approximately 0.5 mm thickness, leaving an area of ​​70 mm². 2 The channel area. After the coating operation is completed, let it stand and cool at room temperature for 30 minutes to allow the oil gel to re-solidify and form a dual-gel fragrance sustained-release carrier.

[0032] Example 2

[0033] This embodiment provides a dual-gel fragrance sustained-release carrier, the preparation method of which is as follows: S1. First, 0.8 g of bamboo powder and 2 g of urea were uniformly dispersed in deionized water and magnetically stirred at 50 °C for 1 h to mix thoroughly. Then, 1 g of carrageenan and 0.3 g of glycerol were added to the above solution, and stirring was continued at 50 °C for 1 h. Next, 2 g of hydroxyethyl cellulose and 3 g of ammonium polyphosphate were mixed into the above solution, and stirring was continued at 50 °C for 2 h. The stable sol precursor was then poured into a cylindrical mold and aged at 4 °C for 24 h to form a gel. The gel was frozen in the mold with liquid nitrogen and then freeze-dried at -60 °C to obtain an aerogel core, denoted as B-E4P3.

[0034] S2. Soybean wax and carnauba wax were melted and mixed at 70°C in a mass ratio of 1:1 to obtain dispersion medium B1D1; then 4 g of trans polyisoprene (TPI) was taken and melted with a corresponding amount of B1D1 sufficient to make the mass ratio of TPI:B1D1 1:5 at 100°C for 6 h to obtain a homogeneous melt; finally, it was cooled to room temperature to allow TPI to form a three-dimensional network and lock B1D1, thus obtaining the TPI-B1D1(1:5) oleogel system.

[0035] S3. Heat the pre-made olegel system to 70°C until it is fully melted and in a fluid state; then, uniformly coat the surface of the aerogel core obtained in step S1 with an olegel coating of approximately 0.5 mm thickness, leaving a 70 mm² area uncoated. 2 The channel area. After the coating operation is completed, let it stand and cool at room temperature for 30 minutes to allow the oil gel to re-solidify and form a dual-gel fragrance sustained-release carrier.

[0036] Example 3

[0037] This embodiment provides a dual-gel fragrance sustained-release carrier, the preparation method of which is as follows: S1. First, dissolve 1 g of sodium alginate in deionized water and stir magnetically at 40°C for 1 h until completely dissolved. Then, add 0.5 g of sorbitol to the above solution and continue stirring at 40°C for 1 h. Next, mix 1.5 g of methylcellulose and 3.5 g of aluminum hypophosphite into the above solution and stir continuously at 40°C for 3 h. Then, pour the stable sol precursor into a cylindrical mold and age it at 0°C for 36 h to form a gel. Freeze the gel in the mold with liquid nitrogen and then freeze-dry it at -40°C to obtain the aerogel core.

[0038] S2. Melt 8g of beeswax, then melt 4g of trans-polyisoprene (TPI) at 90℃ for 6 hours and mix thoroughly to obtain a homogeneous melt. Apply a layer of oleogel coating approximately 0.8mm thick to the surface of the aerogel core prepared in step S1, leaving a 90mm² area uncoated. 2The channel area. After the coating operation is completed, let it stand and cool at room temperature for 60 minutes to allow the oil gel to solidify and form, thus obtaining the dual-gel fragrance sustained-release carrier.

[0039] Example 4

[0040] This embodiment provides a dual-gel fragrance sustained-release carrier, the preparation method of which is as follows: S1. First, dissolve 1 g of gelatin in deionized water and stir magnetically at 60 °C for 2 h until completely dissolved. Then, add 0.2 g of polyethylene glycol to the above solution and continue stirring at 60 °C for 2 h. Next, mix 2.5 g of carboxymethyl cellulose and 2.5 g of zinc borate into the above solution and stir continuously at 60 °C for 2 h. Then, pour the stable sol precursor into a cylindrical mold and age at 4 °C for 18 h to form a gel. Freeze in the mold with liquid nitrogen and then freeze-dry at -50 °C to obtain an aerogel core.

[0041] S2. After melting 20g of paraffin wax, take 4g of trans-polyisoprene (TPI) and melt it at 90℃ for 6 hours to mix it evenly, obtaining a homogeneous melt; uniformly coat the surface of the aerogel core prepared in step S1 with an oleogel coating of approximately 0.5mm thickness, leaving an area of ​​70mm². 2 The channel area. After the coating operation is completed, let it stand and cool at room temperature for 30 minutes to allow the oil gel to solidify and form, thus obtaining the dual-gel fragrance sustained-release carrier.

[0042] Example 5

[0043] This embodiment provides a dual-gel fragrance sustained-release carrier, the preparation method of which is as follows: S1. First, dissolve 1 g of gellan gum in deionized water and stir magnetically at 50°C for 1 h until completely dissolved. Then, add 0.4 g of glycerol to the above solution and continue stirring at 50°C for 1 h. Next, mix 2.3 g of methylcellulose and 2.8 g of ammonium polyphosphate into the above solution and stir continuously at 50°C for 2 h. Then, pour the stable sol precursor into a cylindrical mold and age it at 4°C for 24 h to form a gel. Freeze the gel in the mold with liquid nitrogen and then freeze-dry it at -60°C to obtain the aerogel core.

[0044] S2. Melt 12g of soybean wax, then melt 4g of trans-polyisoprene (TPI) at 100℃ for 6 hours and mix thoroughly to obtain a homogeneous melt. Apply a layer of oleogel coating approximately 0.5mm thick to the surface of the aerogel core obtained in step S1, leaving a 70mm² area uncoated. 2The channel area. After the coating operation is completed, let it stand and cool at room temperature for 30 minutes to allow the oil gel to solidify and form, thus obtaining the dual-gel fragrance sustained-release carrier.

[0045] Comparative Example 1 This comparative example provides a fragrance sustained-release carrier, the preparation method of which is as follows: S1. First, dissolve 1 g of carrageenan in deionized water and stir magnetically at 50°C for 1 h until completely dissolved. Then, add 0.3 g of glycerol to the above solution and continue stirring at 50°C for 1 h. Then, mix different masses of hydroxyethyl cellulose (1.5 g, 2 g, 2.5 g) and 3 g of ammonium polyphosphate into the above solution and stir continuously at 50°C for 2 h. Then, pour the stable sol precursor into a cylindrical mold and age it at 4°C for 24 h to form a gel. Freeze the gel in the mold with liquid nitrogen and then freeze-dry it at -60°C to obtain the E3P3 aerogel core.

[0046] S2. Mix polydimethylsiloxane (PDMS) and curing agent at a mass ratio of 20:1 until homogeneous, and coat the mixture onto the surface of the E3P3 aerogel core. During the coating process, control the exposed surface area of ​​the aerogel to be 70 mm². 2 The mixture was then placed in a 60°C oven and heated for 6 hours to cure the PDMS film on the aerogel surface, thus obtaining the PDMS-E3P3 fragrance carrier.

[0047] Comparative Example 2 This comparative example provides a fragrance sustained-release carrier, the preparation method of which is as follows: S1. First, dissolve 1 g of carrageenan in deionized water and stir magnetically at 50°C for 1 h until completely dissolved. Then, add 0.3 g of glycerol to the above solution and continue stirring at 50°C for 1 h. Then, mix different masses of hydroxyethyl cellulose (1.5 g, 2 g, 2.5 g) and 3 g of ammonium polyphosphate into the above solution and stir continuously at 50°C for 2 h. Then, pour the stable sol precursor into a cylindrical mold and age it at 4°C for 24 h to form a gel. Freeze the gel in the mold with liquid nitrogen and then freeze-dry it at -60°C to obtain the E3P3 aerogel core.

[0048] S2. After melting trans-polyisoprene (TPI-100) at 150℃, it is uniformly coated onto the surface of the E3P3 aerogel core, maintaining a 70mm² exposed surface area of ​​the aerogel during the coating process. 2 The TPI-100-E3P3 fragrance carrier was then solidified at room temperature to form a film.

[0049] Experimental Example 1 Infrared detection was performed using the three aerogel cores E3P3, E4P3, and E5P3 from Example 1, as well as the aerogel core B-E4P3 from Example 2. Their infrared spectra are shown below. Figure 1 As shown.

[0050] from Figure 1 It can be seen that in the range of 3000-3700 cm -1 The characteristic peaks within the range are attributed to the -OH stretching vibrations of carrageenan and hydroxyethyl cellulose, with an enhanced -OH peak in B-E4P3 due to the addition of bamboo powder. At 1621 cm⁻¹... -1 The peak observed at 1049 cm⁻¹ is attributed to the stretching vibration of C=O in D-galactose of carrageenan. This may be due to the increased hydroxyethyl cellulose altering the distribution of polar groups in the matrix, thus changing the electron cloud density of C=O and C=C, and consequently affecting their vibrational intensity. The peak observed at 1049 cm⁻¹ in the spectra of the four aerogels is also relevant. -1 The presence of characteristic absorption peaks for PO bonds indicates that phosphorus-containing functional groups have been successfully modified into the aerogel, confirming that the aerogel possesses flame-retardant properties, thereby preventing the combustion of volatile and flammable components such as essential oils.

[0051] Experimental Example 2 Thermogravimetric analysis (TG) was performed using the three aerogel cores E3P3, E4P3, and E5P3 from Example 1, and the aerogel core B-E4P3 from Example 2. The TG curves are shown below. Figure 2 As shown.

[0052] from Figure 2 It can be seen that all four aerogel cores exhibit three distinct thermal degradation stages, with thermal stability decreasing as the hydroxyethyl cellulose content increases. From 40 to 150℃, the primary process involves the removal of adsorbed and bound water, resulting in the first weight loss peak. Between 150 and 314℃, multiple components undergo synergistic decomposition. Carrageenan in this range experiences glycosidic bond breakage, dehydration, and carbonization, gradually decomposing and losing weight. Hydroxyethyl cellulose undergoes main chain breakage, accompanied by weight loss. Ammonium polyphosphate also begins thermal decomposition, releasing phosphoric acid compounds that catalyze polysaccharide dehydration to form char, creating a relatively stable char layer and reducing char loss at high temperatures. At high temperatures, the remaining char skeleton further oxidizes and decomposes. After final thermal degradation, the mass losses of E3P3, E4P3, and E5P3 are 41.5%, 38.6%, and 36.9%, respectively. This indicates that the higher the hydroxyethyl cellulose content, the more flammable components are present, and the worse the thermal stability of the aerogel.

[0053] Experimental Example 3 Scanning electron microscopy (SEM) was performed on the three aerogel cores E3P3, E4P3, and E5P3 from Example 1, as well as the aerogel core B-E4P3 from Example 2. The SEM images are shown below. Figure 3 As shown.

[0054] Photographs a, b, c, and d show cross-sectional views of the four aerogel cores, revealing parallel pore structures along the ice crystal formation path caused by directional freezing. Photographs e, f, g, and h show longitudinal cross-sectional views of the four aerogel cores, demonstrating the directional orientation of ice crystal growth along the temperature gradient. For E3P3, E4P3, E5P3, and B-E4P3 aerogels, hydrogen bonds form between the three components: hydroxyethyl cellulose, carrageenan, and ammonium polyphosphate. These hydrogen bonds not only enhance the structural stability of the aerogel but also provide excellent support for pore formation, promoting a rich pore system. Furthermore, with increasing hydroxyethyl cellulose content, the pore structure of the aerogel grows directionally along the ice crystal formation path and temperature gradient under directional freezing, further optimizing the pore distribution and connectivity. This results in a denser and more uniform porous structure, attributed to the enhanced hydrogen bonding effect after increasing hydroxyethyl cellulose content, which increases the aerogel porosity. This dense and porous structure gives the aerogel excellent adsorption properties, enabling it to adsorb more essential oils and other fragrance components, providing a good material basis for efficient fragrance storage. When bamboo powder is added to B-E4P3, a supporting structure is added to the pores. When the bamboo powder is evenly distributed, the inside of the pores becomes rough, and more tiny secondary pores and a certain degree of disordered structure are formed in local areas, which reduces the amount of essential oil adsorption.

[0055] Test Example 4 The density of the three aerogel cores E3P3, E4P3, and E5P3 from Example 1, and the aerogel core B-E4P3 from Example 2, was measured, and the results are as follows: Figure 4 As shown.

[0056] from Figure 4 It can be seen that with the increase of hydroxyethyl cellulose content, the density increases, and the amount of aerogel material per unit volume increases. On the one hand, this leads to the filling of some pores, and on the other hand, it reduces the number of sites available for essential oil molecule adsorption. For the B-E4P3 sample, with the addition of bamboo powder, the bamboo powder particles restrict the growth space of ice crystals, resulting in smaller pore sizes than when no bamboo powder was added. When the hydroxyethyl cellulose concentration is high, the aerogel density increases, which hinders the entry of essential oil molecules into the pores, reducing the effective pore space that essential oil molecules can enter, thus leading to a decrease in adsorption capacity.

[0057] Experimental Example 5 The limiting oxygen index (LOI) of the three aerogel cores E3P3, E4P3, and E5P3 from Example 1, and the aerogel core B-E4P3 from Example 2, was measured, and the results are as follows: Figure 5 As shown.

[0058] from Figure 5It can be seen that the E4P3 sample exhibits the best LOI value of 94.7%, indicating that at this ratio, HEC and ammonium polyphosphate (APP) form the best synergistic flame retardant effect. Upon heating, APP promotes the char formation of HEC, forming a continuous and dense char layer, achieving the effect of isolating heat and oxygen. Even after the addition of bamboo powder and urea, the LOI value of the B-E4P3 sample remains high, indicating that the addition of bamboo powder and urea does not weaken the overall flame retardant efficiency. Furthermore, bamboo powder participates in char formation under the action of APP, and urea decomposes to release non-combustible gases. Both, along with the HEC / APP system, play a synergistic role in condensed phase and gas phase flame retardancy, exhibiting excellent flame retardant performance similar to E4P3. However, the LOI of E5P3 decreases with increasing HEC content, indicating that excessively high HEC content may lead to an excessively high proportion of combustible components in the aerogel three-dimensional network structure, weakening the flame retardant efficiency of APP and hindering the formation of a stable char layer.

[0059] Experimental Example 6 The contact angles of the three aerogel cores E3P3, E4P3 and E5P3 of Example 1 and the aerogel core B-E4P3 of Example 2 before and after coating with oleogel were compared.

[0060] Figure 6 The images show photographs of water (stained with brilliant blue) and oil (stained with Sudan III) dripped onto each aerogel core in the uncoated state. Figure 7 The corresponding contact angle test results are shown (left image shows the contact angle of water, right image shows the contact angle of oil). It can be seen that both liquids can penetrate into the internal structure of the aerogel without hindrance. Water and oil are immediately adsorbed upon contact with the aerogel surface, with a contact angle of 0°, demonstrating the aerogel's high affinity for these two liquids.

[0061] Figure 8 The images show photographs of water (stained with brilliant blue) and oil (stained with Sudan III) being dripped onto the surfaces of the oleogel coatings, respectively. Figure 9The corresponding contact angle test results are shown (left image: contact angle of water; right image: contact angle of oil). It can be seen that the coating surface forms a very small contact angle when in contact with n-tetradecane oil droplets. Specifically, the contact angles formed between the coated E3P3, E4P3, E5P3, and B-E4P3 gel surfaces and oil droplets are 8.074°, 12.054°, 7.054°, and 8.434°, respectively. This means that the coating has a high affinity for oil droplets, with no significant difference between the two. In stark contrast, the contact angle formed between the coated E4P3 gel surface and water droplets is 100.5°, the coated E5P3 gel surface and water droplets is 101.7°, and the coated B-E4P3 gel surface and water droplets is 100.2°, indicating that the coating has strong hydrophobicity towards water droplets.

[0062] Experimental Example 7 The appearance of the three aerogel cores E3P3, E4P3, and E5P3 from Example 1, and the aerogel core B-E4P3 from Example 2, after being coated with a TPI-B1D1 (1:5) oleogel coating and after being loaded with fragrance, was compared. The fragrance was a mixture of lavender essential oil and fractionated coconut essential oil at a mass ratio of 4:1. During the impregnation process, visual observation confirmed that no more bubbles were generated on the sample surface, indicating that the internal pores of the aerogel had reached complete saturation. After removing the sample, residual free fragrance was carefully wiped off the surface with a lint-free cloth. The results are as follows. Figure 10 As shown.

[0063] from Figure 10 Based on the appearance morphology and the fragrance loading rate determined by the quality monitoring method, the E3P3 and E4P3 aerogel samples not only exhibited the best fragrance loading performance, but their loading rates were also significantly higher than those of other samples. Furthermore, these two samples also displayed good transparency and a uniform appearance, demonstrating excellent aesthetic appeal.

[0064] Furthermore, we tested the controlled-release effect of two dual-gel fragrance sustained-release carriers, TPI-B1D1(1:5)-E3P3 and TPI-B1D1(1:5)-E4P3, after saturation adsorption of fragrance. The test method was as follows: The loaded samples were exposed to air at an ambient temperature of 25±2℃ and a relative humidity of 60±5%RH. During the 15-day testing period, the samples were precisely weighed daily at regular intervals, and the fragrance loading retention rate was calculated to evaluate the sustained-release performance. Results are as follows: Figure 11 As shown.

[0065] from Figure 11 It can be seen that after 24 hours, TPI-B1D1(1:5)-E3P3 exhibits excellent fragrance retention, with a retention rate of (97.33±0.01)%. Figure 12 As shown in Figure a); the retention rate of TPI-B1D1(1:5)-E3P3 was slightly lower, at (96.33±0.01)% (as shown in Figure a). Figure 12 (As shown in b). After 15 days of continuous observation, both materials maintained high fragrance loading, with TPI-B1D1(1:5)-E3P3 achieving a final retention rate of (68.33±0.01)% and TPI-B1D1(1:5)-E4P3 achieving (69.83±0.01)%. These results indicate that the dense protective layer formed by surface sealing treatment can significantly reduce the diffusion rate of fragrance molecules and effectively inhibit the volatilization process. The fragrance carrier product developed based on this process not only has excellent initial fragrance loading capacity but also achieves continuous and stable fragrance release. This novel material, combining high loading capacity and sustained-release properties, provides reliable technical support for the development of long-lasting aromatic products.

[0066] Experimental Example 8 The dual-gel fragrance sustained-release carrier TPI-B1D1(1:5)-E3P3 prepared in Example 1, and the fragrance carriers PDMS-E3P3 and TPI-100-E3P3 prepared in Comparative Examples 1 and 2 were subjected to DSC analysis and volatility testing. The test results are as follows: Figure 12 As shown.

[0067] The methods for testing volatility include: After the three fragrance carriers were fully absorbed into the fragrance, their mass change was continuously tested at 50°C. The volatilization rate was recorded every 5 minutes for 50 minutes to obtain data.

[0068] Figure 12 Figure a shows the heat flow-temperature curve of the PDMS-E3P3 fragrance carrier in Comparative Example 1. Its heat flow curve is relatively flat near 50℃, with no obvious endothermic or exothermic peaks, indicating that the material does not undergo a phase change at this temperature.

[0069] Figure 12 Figures b and c show the heat flow-temperature curves of the TPI-100-E3P3 fragrance carrier in Comparative Example 2 and the TPI-B1D1(1:5)-E3P3 fragrance carrier in Example 1, respectively. It can be seen that both fragrance carriers exhibit significant endothermic-exothermic peaks near 50°C, reflecting a phase transition under these conditions. Comparing the peak areas, the TPI-B1D1(1:5)-E3P3 fragrance carrier has a larger phase transition enthalpy than the TPI-100-E3P3 fragrance carrier, thus exhibiting better endothermic phase transition performance.

[0070] Figure 12Figure d shows the change in volatilization rate of the three fragrance carriers at 50°C over time. Among them, the PDMS-E3P3 fragrance carrier, lacking phase change capability, exhibits a volatilization rate that increases continuously and uniformly over time. In contrast, the TPI-100-E3P3 fragrance carrier and the TPI-B1D1(1:5)-E3P3 fragrance carrier of Example 1, possessing phase change endothermic capability, have lower release rates at 50°C, and their release amounts over the same time are far lower than those of the PDMS-E3P3 fragrance carrier, which lacks phase change capability.

[0071] In summary, this invention provides a dual-gel fragrance sustained-release carrier and its preparation method, comprising an aerogel core and an olegel coating applied to the surface of the aerogel core. The aerogel core is prepared from a polysaccharide-based gelling agent, a polyol plasticizer, a pore-regulating agent, and a flame retardant. The olegel coating is obtained by mixing a lipophilic gelling agent and a wax-based dispersion medium. The aerogel, with its ultra-high specific surface area and chemically modifiable inner and outer surfaces, can uniformly disperse and stably load fragrance components. Its continuous nanopores provide controllable diffusion paths, achieving sustained and controlled release effects. The three-dimensional network formed by the olegel has excellent phase-change heat storage capabilities, absorbing heat from the environment during heating to prevent rapid release of internal fragrance components. This allows for precise control of the evaporation rate of the fragrance components. The synergistic effect of these two components achieves long-term linear release of the fragrance components, solving the problems of uneven release and short duration of traditional fragrance carriers.

[0072] 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 dual-gel fragrance sustained-release carrier, characterized in that, It includes an aerogel core and an oleogel coating applied to the surface of the aerogel core; The aerogel core is prepared from a polysaccharide-based gelling agent, a polyol plasticizer, a pore regulator, and a flame retardant; the oleogel coating is prepared from a mixture of a lipophilic gelling agent and a wax-based dispersion medium.

2. The dual-gel fragrance sustained-release carrier according to claim 1, characterized in that, In the aerogel core, the mass ratio of the polysaccharide gelling agent, the polyol plasticizer, the pore control agent, and the flame retardant is 1:(0.2~0.5):(1.5~2.5):(2.5~3.5).

3. The dual-gel fragrance sustained-release carrier according to claim 2, characterized in that, The polysaccharide-based gelling agent includes at least one of carrageenan, sodium alginate, gelatin, agar, and gellan gum; the polyol plasticizer includes at least one of glycerol, sorbitol, polyethylene glycol, and propylene glycol; the pore-regulating agent includes at least one of hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, and microcrystalline cellulose; and the flame retardant includes at least one of ammonium polyphosphate, triethyl phosphate, aluminum hypophosphite, expanded graphite, and zinc borate.

4. The dual-gel fragrance sustained-release carrier according to claim 1, characterized in that, The aerogel core also includes 1wt% to 10wt% of bio-based filler, which includes at least one of bamboo powder, straw powder, coffee grounds, and lignin.

5. The dual-gel fragrance sustained-release carrier according to claim 1, characterized in that, The mass ratio of the lipophilic gelling agent to the wax-based dispersion medium is 1:(2~10).

6. The dual-gel fragrance sustained-release carrier according to claim 1, characterized in that, The lipophilic gelling agent includes trans-polyisoprene; the wax-based dispersion medium includes at least one of soybean wax, carnauba wax, beeswax, candelilla wax, and paraffin wax.

7. The dual-gel fragrance sustained-release carrier according to claim 1, characterized in that, The thickness of the oleogel coating is 0.2~1.0 mm. A portion of the surface of the aerogel core is left uncoated as a channel area, with an area of ​​50~100 mm². 2 .

8. A method for preparing a dual-gel fragrance sustained-release carrier as described in any one of claims 1 to 7, characterized in that, include: S1. The polysaccharide-based gelling agent, the polyol plasticizer, the pore control agent, and the flame retardant are dissolved in water to form a sol, and the sol is poured into a mold to form the aerogel core. S2. The lipophilic gelling agent and the wax-based dispersion medium are melt-mixed and coated onto the surface of the aerogel core. After cooling and solidification, the oleogel coating is formed.

9. The preparation method according to claim 8, characterized in that, In step S1, the aerogel is stirred and dissolved at 40~60℃ to form the sol, then aged and shaped at 0~5℃, and freeze-dried at -60~-40℃ to obtain the aerogel core.

10. The preparation method according to claim 8, characterized in that, In step S2, the melting and mixing temperature is 90~110℃.

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