Bio-based aerogel film and preparation method thereof

Abstract

The invention discloses a bio-based aerogel film and a preparation method thereof. The bio-based aerogel film comprises chondrus crispus powder, glucomannan, water and an auxiliary agent, the preparation method of the bio-based aerogel film comprises the following steps: S1, solution preparation: adding water and other raw materials, and uniformly stirring to obtain a mixed solution; s2, gelation treatment: pouring the mixed solution into a mold, and refrigerating to obtain a gel sample; and S3, freeze drying: freezing the gel sample at a preset temperature, and then carrying out sublimation drying at a preset vacuum degree to obtain the bio-based aerogel film. The bio-based aerogel film has high porosity and specific surface area, can adsorb and load a large number of functional components, and has excellent air permeability and stability.

Description

Technical Field

[0001] This invention relates to the fields of medical devices and cosmetics, and in particular to a bio-based aerogel film and its preparation method. Background Technology

[0002] Skin masks are a popular product in the beauty and skincare industry, providing hydration and nutrients to the skin and offering some repair and maintenance benefits. Traditional skin masks often use non-woven fabric as the base material, combined with various functional ingredients, which has some limitations: firstly, the limited absorbency and breathability of non-woven fabrics lead to uneven and prolonged release of functional ingredients, affecting the mask's effectiveness; secondly, non-woven fabrics are mostly made of thin fibers such as PP, PET, or viscose, which are easily deformed and damaged after soaking in essence, making them difficult to clean and reuse, thus generating a significant amount of disposable waste and burdening the environment. In recent years, with consumers' increasing demands for environmental protection and product performance, there is an urgent need for a new type of skin mask material to meet market demands.

[0003] Crystal masks that do not require non-woven fabric as a medium and dissolve upon heating have attracted widespread attention due to their excellent transparency, flexibility, and moisturizing properties. However, a highly effective moisturizing and soothing gel mask and its preparation method, disclosed in CN114796050B, presents challenges in extracting its active ingredients, such as olive leaf extract and starfish repair factor. These extractions are difficult and costly, and the polyphenols, flavonoids, and starfish regeneration and repair factor in the olive leaf extract are temperature-sensitive, raising concerns about stability during preparation and potentially weakening the water-locking and sustained-release effects.

[0004] Furthermore, crystal film still suffers from problems such as difficulty in forming and poor stability, and is prone to issues such as essence leakage and film material damage during storage and use, affecting user experience and product shelf life. Summary of the Invention

[0005] The main objective of this invention is to provide a bio-based aerogel film and its preparation method, aiming to solve the technical problems that the films obtained by existing preparation methods have low stability and cannot simultaneously achieve environmental protection and functionality.

[0006] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a bio-based aerogel film, wherein the bio-based aerogel film comprises carrageenan powder, glucomannan, water and additives.

[0007] The preparation method of the bio-based aerogel film includes the following steps:

[0008] S1. Solution preparation: Add water and other raw materials, stir evenly, heat to obtain a mixed solution;

[0009] S2. Gelation treatment: Pour the mixed solution into a mold and refrigerate to obtain a gel sample;

[0010] S3. Freeze-drying: Freeze the gel sample at a preset temperature and then sublimate and dry it under a preset vacuum to obtain the bio-based aerogel film.

[0011] The bio-based aerogel film of this invention uses bio-based materials such as carrageenan powder as the main raw material. It is derived from natural substances, is biodegradable, and can decompose into harmless substances in the natural environment. Compared with traditional petrochemical-based film materials, it greatly reduces environmental pollution, conforms to the concept of sustainable development, and has excellent environmental protection performance.

[0012] This invention discloses a bio-based aerogel film. A specific process is used to uniformly mix carrageenan powder, glucomannan, water, and additives. The dissolution temperature is low, preventing damage to the components in the film. After dissolution, refrigeration forms a gel sample. Both carrageenan powder and glucomannan are natural colloids that can form a stable three-dimensional network through intermolecular forces, preventing collapse. Glucomannan serves as the skeletal component for film formation, while carrageenan powder provides synergistic adhesion and thickening effects. Water fills the gel system. The gel sample is then frozen and sublimated to obtain a porous bio-based aerogel film with a high specific surface area. The numerous pores in this bio-based aerogel film can adsorb and load a large amount of functional ingredients. Due to its unique network structure, the functional ingredients are evenly distributed and slowly released, prolonging the moisturizing and nutrient supply time of the film, improving skincare effects, and allowing the skin to more fully absorb the effective ingredients. This significantly improves skin dryness, dehydration, and aging, resulting in remarkable skincare benefits.

[0013] Preferably, the bio-based aerogel film not only combines natural biological ingredients such as carrageenan and glucomannan, but also adds active ingredients such as vitamin C, hyaluronic acid, collagen, natural plant extracts, and probiotics loaded into the aerogel network to achieve highly effective skin care.

[0014] Preferably, the solution preparation step more specifically includes: adding water and other raw materials, stirring evenly, heating to 80-90°C, and maintaining the temperature while stirring for 20-40 minutes to obtain a mixed solution. The stirring temperature of 80-90°C in this invention will not cause the active ingredients to decompose, but will also allow glucomannan to absorb water and swell, which is beneficial for uniform mixing and gel formation.

[0015] Preferably, step S2: gelation treatment more specifically includes: pouring the mixed solution into a mold and refrigerating it at 3-5°C for 10-5 minutes to obtain a gel sample. Pouring the mixed solution into a mold for film preparation and refrigerating it allows the molecular chains in the gel network to fully cross-link, ensuring uniform loading of functional components and guaranteeing the moisturizing and mechanical properties of the bio-based aerogel film.

[0016] Preferably, step S3, the freeze-drying step, more specifically includes: freezing the gel sample at -45°C to -50°C for 3 to 4 hours, then heating it under a vacuum of 1 Pa to sublimate and dry the gel sample for 10 to 30 hours, obtaining the bio-based aerogel membrane. Low-pressure drying for 10 to 30 hours removes free water while retaining bound water, avoiding the shrinkage issue common in traditional aerogel drying. At temperatures above -45°C or for less than 3 hours, the moisture in the gel sample will not be fully frozen, making it difficult to ensure pores of a certain size during freeze-drying. Conversely, freezing at temperatures below -50°C or for more than 4 hours is more wasteful of resources.

[0017] Preferably, the step of obtaining the bio-based aerogel film includes a post-processing stage: slitting, trimming to remove burrs, and packaging.

[0018] Preferably, the additive includes a cross-linking agent, which includes at least one of calcium chloride and potassium chloride. Calcium chloride and potassium chloride promote cross-linking; the potassium ions in potassium chloride can activate carrageenan powder and accelerate gelation; and the calcium ions in calcium chloride can connect with the hydroxyl groups in glucomannan to enhance stability.

[0019] Preferably, the additives include an emulsifier, which includes at least one of polysorbate 80, hydrogenated castor oil, and Span 20. Preferably, the additives include a thickener, which includes at least one of agar, gellan gum, carbomer, xanthan gum, cellulose gum, and locust bean gum. Preferably, the additives include a humectant and a preservative, where the humectant includes at least one of glycerin, 1,2-hexanediol, trehalose, sodium hyaluronate, chitosan, polyethylene glycol, and propylene glycol; and the preservative includes at least one of p-hydroxyacetophenone, phenoxyethanol, methylparaben, and propylparaben. Humectants such as glycerin can lower the freezing point. When freezing gel samples, the humectant can reduce the damage to the framework caused by excessively large ice crystals. Further drying under low pressure with a gradient temperature increase avoids the collapse of the network structure's pores.

[0020] The present invention also provides a bio-based aerogel film, wherein the bio-based aerogel film comprises the following components in weight percentage: glycerol 3%–30%, carrageenan powder 0.1%–8%, glucomannan 0.1%–5%, p-hydroxyacetophenone 0.05%–2%, 1,2-hexanediol 0.01%–5%, calcium chloride 0.01%–1%, gellan gum 0.1%–2%, potassium chloride 0.01%–1%, phenoxyethanol 0.01%–1%, polysorbate 80 0.01%–3%, trehalose 0.3%–8%, carbomer 0.1%–3%, xanthan gum 0.1%–5%, cellulose gum 0.1%–5%, sodium hyaluronate 0.01%–3%, and the balance being water.

[0021] Through extensive experimental research, the inventors discovered that bio-based aerogel films with proportions of the above-mentioned components have better water absorption and retention effects, as well as superior flexibility and stability.

[0022] Beneficial effects:

[0023] 1. The bio-based aerogel film of the present invention has high porosity and specific surface area, which can adsorb and load a large number of functional ingredients, such as vitamins, hyaluronic acid, natural plant extracts, etc., and due to its unique network structure, it can make the essence evenly distributed and slowly released, prolonging the moisturizing and nutrient supply time of the film, improving the skin care effect, enabling the skin to absorb the effective ingredients more fully, improving skin dryness, dehydration, aging and other problems, and achieving significant skin care effect.

[0024] 2. In this invention, no complex active ingredients are needed; the effect is achieved solely through the physical properties of aerogel and the synergistic effect of its components. The porous structure of the aerogel material gives it excellent breathability, allowing the skin to breathe freely and avoiding the stuffiness and discomfort caused by poor breathability in traditional patches. Simultaneously, the bio-based aerogel patch of this invention is lightweight and soft, with good adhesion, providing users with a comfortable and pleasant experience, and exhibiting excellent breathability and comfort.

[0025] 3. The freeze-dried aerogel film has better stability during storage and use, and is less prone to problems such as essence separation, deterioration, and film deformation, thus extending the product's shelf life and reducing the company's production costs and consumers' usage risks. Detailed Implementation

[0026] The present invention will be further described below with reference to embodiments. It should be noted that the following description is only for explaining the present invention and does not limit its content. Unless otherwise specified, the experimental methods used in the following embodiments are all conventional methods. Unless otherwise specified, the materials and reagents used in the following embodiments can be obtained commercially.

[0027] Unless otherwise specified, the reagents used in the following examples and comparative examples are conventional reagents and can be purchased from conventional reagent manufacturers and distributors.

[0028] Example 1: Bio-based aerogel film and its preparation method

[0029] The bio-based aerogel film is composed of the following components and their weight percentages: 5% glycerol, 5% carrageenan, 5% glucomannan, 0.5% p-hydroxyacetophenone, 0.5% 1,2-hexanediol, 0.03% calcium chloride, 0.6% gellan gum, 0.05% potassium chloride, 1% polysorbate 80, 4% trehalose, 1% carbomer, 2% xanthan gum, 2% cellulose gum, 0.5% sodium hyaluronate, and the balance being water.

[0030] The preparation method of the bio-based aerogel film is as follows:

[0031] S1. Solution preparation: Add water and other raw materials in sequence, stir evenly, heat to 85°C, keep warm and stir for 30 minutes to obtain a mixed solution;

[0032] S2. Gelation treatment: Pour the mixed solution into a mold and refrigerate it at 4°C for 1 minute to obtain a gel sample;

[0033] S3. Freeze-drying: Freeze the gel sample at -50℃ for 4 hours, then heat it under a vacuum of 1 Pa to sublimate and dry the gel sample for 24 hours to obtain the bio-based aerogel film.

[0034] Example 2 Bio-based aerogel film and its preparation method

[0035] The bio-based aerogel film is composed of the following components and their weight percentages: 5% glycerol, 3% carrageenan, 2% glucomannan, 0.5% p-hydroxyacetophenone, 0.5% 1,2-hexanediol, 0.03% calcium chloride, 0.6% gellan gum, 0.05% potassium chloride, 1% polysorbate 80, 4% trehalose, 1% carbomer, 2% xanthan gum, 2% cellulose gum, 0.5% sodium hyaluronate, and the balance being water.

[0036] The difference between the formulation of this embodiment and that of Embodiment 1 is that the content of carrageenan and glucomannan is different in this embodiment.

[0037] The preparation method of the bio-based aerogel mask is as follows:

[0038] S1. Solution preparation: Add water and other raw materials in sequence, stir evenly, heat to 80℃, keep warm and stir for 15 minutes to obtain a mixed solution;

[0039] S2. Gelation treatment: Pour the mixed solution into a mold and refrigerate it at 4°C for 4 minutes to obtain a gel sample;

[0040] S3. Freeze-drying: Freeze the gel sample at -50°C for 4 hours, then heat it under a vacuum of 1 Pa to sublimate and dry the gel sample for 24 hours to obtain the bio-based aerogel mask.

[0041] Example 3 Bio-based aerogel film and its preparation method

[0042] The bio-based aerogel film is composed of the following components and their weight percentages: 5% glycerin, 5% carrageenan, 5% glucomannan, 0.5% p-hydroxyacetophenone, 0.5% 1,2-hexanediol, 0.03% calcium chloride, 0.05% potassium chloride, 1% polysorbate 80, 4% trehalose, 1% carbomer, 2% xanthan gum, 2% cellulose gum, 0.5% sodium hyaluronate, and the balance being water.

[0043] The difference between the formulation of this embodiment and that of Embodiment 1 is that this embodiment does not contain gellan gum.

[0044] The preparation method of the bio-based aerogel film is as follows:

[0045] S1. Solution preparation: Add water and other raw materials in sequence, stir evenly, heat to 85°C, keep warm and stir for 30 minutes to obtain a mixed solution;

[0046] S2. Gelation treatment: Pour the mixed solution into a mold and then place it in an environment of 4°C for 1 min to obtain a gel sample;

[0047] S3. Freeze-drying: Freeze the gel sample at -50℃ for 4 hours, then heat it under a vacuum of 1 Pa to sublimate and dry the gel sample for 24 hours to obtain the bio-based aerogel film.

[0048] Comparative Example 1

[0049] The bio-based aerogel film is composed of the following components and their weight percentages: 5% glycerol, 5% carrageenan, 5% glucomannan, 0.5% p-hydroxyacetophenone, 0.5% 1,2-hexanediol, 0.03% calcium chloride, 0.6% gellan gum, 0.05% potassium chloride, 1% polysorbate 80, 4% trehalose, 1% carbomer, 2% xanthan gum, 2% cellulose gum, 0.5% sodium hyaluronate, and the balance being water.

[0050] The components of this comparative example are consistent with those of Example 1, which has the best effect, but the key step S3 in the preparation method is different.

[0051] The preparation method of the bio-based aerogel film is as follows:

[0052] S1. Solution preparation: Add water and other raw materials in sequence, stir evenly, heat to 85°C, keep warm and stir for 30 minutes to obtain a mixed solution;

[0053] S2. Gelation treatment: Pour the mixed solution into a mold and refrigerate it at 4°C for 1 minute to obtain a gel sample;

[0054] S3. Freeze-drying: Freeze the gel sample at -50℃ for 4 hours, then heat it under a vacuum of 5Pa to sublimate and dry the gel sample for 30 hours to obtain the bio-based aerogel film.

[0055] Comparative Example 2

[0056] The bio-based aerogel film is composed of the following components and their weight percentages: 5% glycerin, 5% carrageenan, 5% glucomannan, 0.5% p-hydroxyacetophenone, 0.5% 1,2-hexanediol, 0.03% calcium chloride, 0.6% gellan gum, 0.05% potassium chloride, 1% polysorbate 80, 4% trehalose, 1% carbomer, 2% xanthan gum, 2% cellulose gum, 0.5% sodium hyaluronate, and the balance being water. The composition is consistent with that of the preferred embodiment 1, except for the key step S1 in the preparation method.

[0057] The preparation method of the bio-based aerogel film is as follows:

[0058] S1. Solution preparation: Add water and other raw materials in sequence, stir evenly, heat to 75°C, keep warm and stir for 10 minutes to obtain a mixed solution;

[0059] S2. Gelation treatment: Pour the mixed solution into a mold and refrigerate it at 4°C for 1 minute to obtain a gel sample;

[0060] S3. Freeze-drying: Freeze the gel sample at -50℃ for 4 hours, then heat it under a vacuum of 1 Pa to sublimate and dry the gel sample for 24 hours to obtain the bio-based aerogel film.

[0061] Comparative Example 3

[0062] The bio-based aerogel film is composed of the following components and their weight percentages: 5% glycerin, 5% carrageenan, 5% glucomannan, 0.5% p-hydroxyacetophenone, 0.5% 1,2-hexanediol, 0.03% calcium chloride, 0.6% gellan gum, 0.05% potassium chloride, 1% polysorbate 80, 4% trehalose, 1% carbomer, 2% xanthan gum, 2% cellulose gum, 0.5% sodium hyaluronate, and the balance being water. The composition is consistent with that of the preferred embodiment 1, except for the key step S3 in the preparation method.

[0063] The preparation method of the bio-based aerogel film is as follows:

[0064] S1. Solution preparation: Add water and other raw materials in sequence, stir evenly, heat to 85°C, keep warm and stir for 30 minutes to obtain a mixed solution;

[0065] S2. Gelation treatment: Pour the mixed solution into a mold and refrigerate it at 4°C for 1 minute to obtain a gel sample;

[0066] S3. Heating and drying: The gel sample is dried at 40°C for 24 hours to obtain the bio-based aerogel film.

[0067] Test 1: Water Absorption Rate Test

[0068] The water absorption rate of the bio-based aerogel films prepared in the above embodiments and comparative examples was tested. The film samples were cut into 2cm × 2cm squares, and their initial mass (m0) was measured under dry conditions. They were then immersed in deionized water for 30 minutes, and after removal, excess surface moisture was gently absorbed with filter paper. The mass after water absorption (m1) was immediately measured. The water absorption rate was calculated using the formula: Water absorption rate (%) = (m1 - m0) / m0 × 100%. The test results are shown in Table 1.

[0069] Table 1:

[0070] Water absorption rate / % Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Water absorption rate 1 2971 2132 1508 782 694 612 Water absorption rate 2 2996 2033 1499 805 712 603 Water absorption rate 3 3036 1997 1521 815 708 596 average value 3001 2054 1509 800 704 603

[0071] The results above show that the water absorption rates of Examples 1-3 are much higher than those of Comparative Examples 1-3. The inventors reasonably speculate that: Comparative Example 1, due to changes in the vacuum degree of freeze-drying in the preparation method, had a higher vacuum degree, slower ice sublimation, and longer water retention time, which easily caused the gel network to shrink due to soaking, thus reducing the porosity and resulting in a lower water absorption rate; the stirring conditions of Comparative Example 2 were insufficient to completely dissolve the glucomannan, resulting in an unstable gel structure and poor water absorption; the drying process in Comparative Example 3 damaged the colloidal network, leading to a significant decrease in water absorption rate; while the bio-based aerogel film provided by this invention shows good water absorption performance and can provide sufficient moisture to the skin.

[0072] Test 2 Mechanical Property Test

[0073] The tensile strength and elongation at break of the films prepared in the above embodiments and comparative examples were tested using a universal testing machine. The samples were clamped onto a tensile testing machine and stretched at a speed of 100 mm / min. The maximum force at break and the gauge length elongation were recorded, and the tensile strength (MPa) and elongation at break (%) were calculated. The aerogel films provided by the embodiments of the present invention have significantly improved mechanical properties, meeting the requirements for stretching and bonding in daily use. They are not easily damaged and have good practicality and durability.

[0074]

[0075]

[0076] The results above show that the bio-based aerogel film provided by this invention has excellent tensile strength and elongation at break, good flexibility, and different preparation experimental parameters also affect the mechanical properties of the film.

[0077] Test 3 Stability Test

[0078] 1. Accelerated stability test: The bio-based aerogel film provided by the present invention was subjected to accelerated stability test under storage conditions of 40℃±2℃ and 75%±5% humidity. The stability of the samples was tested at different time points of 0 months, 1 month, 2 months and 3 months. The test results are shown in the table below.

[0079]

[0080]

[0081]

[0082]

[0083] 2. Cold-melt cycle test: The cold-melt cycle stability was investigated under storage conditions of -5℃±2℃, 24h and 40℃±2℃, 24h. The stability of the samples was tested at 0, 1, 2, 3, 4, 5 and 6 cycles. The results of the cold-melt cycle stability test are as follows.

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090] The results of accelerated testing and cold-melt cycle testing show that the appearance, color, odor, and mechanical properties of the bio-based aerogel film of the present invention remain basically unchanged after 3 months of accelerated testing or 6 cycles of cold melt testing. Its antibacterial properties are also consistently good, and its sealing performance, cold and heat resistance in commercial packaging are also excellent.

[0091] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a bio-based aerogel film, characterized in that, The bio-based aerogel film comprises carrageenan powder, glucomannan, water, and additives; The preparation method of the bio-based aerogel film includes the following steps: S1. Solution preparation: Add water and other raw materials, stir evenly, heat to obtain a mixed solution; S2. Gelation treatment: Pour the mixed solution into a mold and refrigerate to obtain a gel sample; S3. Freeze-drying: Freeze the gel sample at a preset temperature and then sublimate and dry it under a preset vacuum to obtain the bio-based aerogel film.

2. The method for preparing the bio-based aerogel film according to claim 1, characterized in that, The S1 solution preparation step more specifically includes: adding water and other raw materials and stirring until uniform; heating to 80-90°C and maintaining the temperature while stirring for 20-40 minutes to obtain a mixed solution.

3. The method for preparing the bio-based aerogel film according to claim 1, characterized in that, The S2: gelation treatment step more specifically includes: pouring the mixed solution into a mold and refrigerating it at 3-5°C for 10-5 minutes to obtain a gel sample.

4. The method for preparing the bio-based aerogel film according to claim 1, characterized in that, The S3: freeze-drying step more specifically includes: freezing the gel sample at -45℃ to -50℃ and maintaining it for 3 to 4 hours, and then heating it under a vacuum of 1 Pa to sublimate and dry the gel sample for 10 to 30 hours to obtain the bio-based aerogel film.

5. The method for preparing the bio-based aerogel film according to claim 1 or 4, characterized in that, The process of obtaining the bio-based aerogel film includes a post-processing stage: slitting, trimming to remove burrs, and packaging.

6. The method for preparing the bio-based aerogel film according to claim 1, characterized in that, The additive includes a crosslinking agent, which includes at least one of calcium chloride and potassium chloride.

7. The method for preparing the bio-based aerogel film according to claim 1, characterized in that, The additives include emulsifiers, which include at least one of polysorbate 80, hydrogenated castor oil, and Span 20.

8. The method for preparing the bio-based aerogel film according to claim 1, characterized in that, The additives include thickeners, which include at least one of agar, gellan gum, carbomer, xanthan gum, cellulose gum, and locust bean gum.

9. The method for preparing the bio-based aerogel film according to claim 1, characterized in that, The adjuvants include humectants and preservatives. The humectants include at least one of glycerin, 1,2-hexanediol, trehalose, sodium hyaluronate, chitosan, polyethylene glycol, and propylene glycol. The preservatives include at least one of p-hydroxyacetophenone, phenoxyethanol, methylparaben, propylparaben, and iodopropynyl butylcarbamate.

10. A bio-based aerogel film, characterized in that, The bio-based aerogel film, prepared by any one of claims 1 to 9, comprises the following components in weight percentages: 3% to 30% glycerol, 0.1% to 8% carrageenan, 0.1% to 6% glucomannan, 0.05% to 2% p-hydroxyacetophenone, 0.01% to 5% 1,2-hexanediol, 0.01% to 1% calcium chloride, 0.1% to 2% gellan gum, 0.01% to 1% potassium chloride, 0.01% to 1% phenoxyethanol, 0.01% to 3% polysorbate 80, 0.3% to 8% trehalose, 0.1% to 3% carbomer, 0.1% to 5% xanthan gum, 0.1% to 5% cellulose gum, 0.01% to 3% sodium hyaluronate, and the balance being water.

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