Preparation method of algae-based pure vegetarian leather based on double-network gel system

Abstract

The invention provides a preparation method of algae-based pure plain leather based on a dual-network gel system. According to the method, natural polysaccharide sodium alginate extracted from seaweed and xanthan gum obtained through microbial fermentation are used as raw materials, and a cross-linking reaction of the raw materials is accurately regulated and controlled to form a double-network structure formed by cross-linked alginate serving as a rigid network and a flexible xanthan gum hydrogen bond network; and the material is reinforced and toughened by utilizing the synergistic complementary characteristics of the two, and the size and deformation stability are kept. Meanwhile, the leather tanning fat liquoring principle is used for reference, and natural grease is introduced, so that the softness and durability of the material are effectively improved. According to the method, natural and renewable polysaccharide resources are adopted, animal components are not contained, and animal ethical problems and use of harmful chemicals are avoided. The method has the advantages of simple process, abundant raw materials, low cost, excellent mechanical properties of pure plain leather products, short production period, large-scale industrial production and wide market prospect, and particularly has the potential of becoming a green and environment-friendly substitute material in the fields of fashion and furniture.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, specifically relating to a method for preparing algae-based vegan leather based on a dual-network gel system. Background Technology

[0002] Leather is a natural material derived from animals, obtained through physical and chemical processes such as hair removal and tanning. Due to its durability, softness, and natural aesthetic properties, it is widely used in clothing, footwear, furniture, and accessories. The unique texture and appearance of leather make it a popular commodity, with its market value projected to reach nearly $360 billion by 2025. However, as environmental protection and animal ethics issues gain increasing public attention, the production and use of traditional leather are facing growing controversy. Leather is primarily sourced from livestock, and livestock farming has a significant environmental impact, including deforestation, greenhouse gas emissions, and the destruction of ecosystems by animal waste. Furthermore, the chemicals used in traditional leather tanning processes, such as chromium salts and chlorides, pose potential environmental pollution and health risks. In particular, chromium-containing waste may release toxic hexavalent chromium (Cr(VI)), which is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC) and a Group 1 carcinogen by the U.S. Environmental Protection Agency (EPA). The large amount of solid waste generated during leather tanning, especially chromium-containing solid waste, is also a serious environmental problem.

[0003] Against this backdrop, vegan leather has emerged as an environmentally friendly alternative. In recent years, many vegan leather materials based on biomass such as plants, mushrooms, and algae have gradually appeared on the market, especially leather alternatives prepared from mycelium and other natural polysaccharides. Among these alternatives, algae-based vegan leather, based on a dual-network gel system, has attracted widespread attention. Algae-based vegan leather is mainly made from biomaterials such as alginate, alginic acid, and natural oils, resulting in lower production costs, lower carbon emissions, and lower energy consumption. It also possesses excellent biodegradability, thus demonstrating outstanding environmental friendliness. The unique advantages of algae-based vegan leather lie in its renewable source and low environmental impact during processing. Algae resources are abundant and grow rapidly, requiring no arable land or large amounts of water, greatly reducing the burden on the environment. Compared to traditional leather, algae-based vegan leather uses fewer chemicals in its production process, avoiding dependence on harmful substances. Furthermore, the biodegradability of algae-based vegan leather after use is also a key characteristic; it can degrade rapidly without polluting the environment, meeting the current societal demand for sustainable materials.

[0004] Dual-network gel systems, as a novel material structure, enhance the mechanical properties and stability of materials by combining two different types of gel substances. This technology provides new insights for the development of algae-based vegan leather. By optimizing the structure and strength of the gel network, not only are its durability and flexibility improved, but this alternative material also approaches traditional animal leather in appearance, feel, and performance. The algae-based dual-network gel system combines the hydrophilicity of natural polysaccharides with the hydrophobicity of oily substances, giving it excellent balance and adaptability, better meeting the needs of different application scenarios.

[0005] Therefore, algae-based vegan leather, as an environmentally friendly and sustainable material, has broad development prospects and the potential to replace traditional leather. With continuous technological advancements and changing market demands, algae-based vegan leather will play an increasingly important role in clothing, furniture, and other fields, driving the leather industry towards a more environmentally friendly and sustainable direction. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing algae-based vegan leather based on a dual-network gel system. This method is simple to implement and does not use any restricted chemicals. The resulting bio-based vegan leather is completely biodegradable at the end of its lifespan.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] (1) Sodium alginate, xanthan gum, and oily substance A are added to water in sequence and stirred thoroughly to obtain a film-forming solution; wherein the mass ratio of xanthan gum to sodium alginate is (0.1~2):1;

[0009] (2) Dissolve crosslinking agent B in deionized water and slowly add it to the film-forming solution while stirring to ensure that the crosslinking agent is evenly distributed throughout the solution. Use a buffer solution to adjust the pH of the film-forming solution to 3.5 to 10.5 and control the temperature at 40 to 60°C to ensure the optimal crosslinking efficiency.

[0010] (3) Pour the cross-linked solution evenly into the mold to form a film, then immerse it in CaCl2 solution for cross-linking, and then wash it repeatedly; wherein the mass fraction of CaCl2 solution is 1-20%;

[0011] (4) Place the cross-linked membrane in a humidity-controlled environment to air dry naturally, with the temperature controlled at 10-150℃ and the humidity controlled at 50-100% to maintain the flexibility of the membrane.

[0012] (5) After drying, gently wash the membrane with warm water or dilute acetic acid solution to remove unreacted crosslinking agent B. After washing, air dry at room temperature until constant weight to maintain the membrane's flexibility and appropriate humidity.

[0013] The method for preparing algae-based vegan leather based on a dual-network gel system is characterized in that the oily substance A used in (1) is one or more of vegetable oil, mineral oil, edible oil, olive oil, soybean oil, corn oil, rapeseed oil, coconut oil or a mixture thereof.

[0014] The method for preparing algae-based vegan leather based on a dual-network gel system is characterized in that the crosslinking agent B used in (2) is one or more of tannic acid, phenolic compounds, divalent metal salts, glutaraldehyde, pentanediol or mixtures thereof.

[0015] The method for preparing algae-based vegan leather based on a dual-network gel system is characterized in that the amount of crosslinking agent A added is 0.1-5% of the total mass of xanthan gum and sodium alginate.

[0016] The method for preparing algae-based vegan leather based on a dual-network gel system is characterized in that the film drying time is 6 to 96 hours until constant weight is achieved.

[0017] Beneficial effects

[0018] Compared with existing technologies, this invention has many positive effects and advantages, which can be summarized as follows:

[0019] (1) The algae-based vegan leather of the present invention does not use any animal ingredients, thus avoiding the ethical controversies of traditional leather and conforming to the current social concern for animal protection. At the same time, it uses natural algae as raw materials, which does not involve the use of animal resources and meets the requirements of sustainable development and environmental protection.

[0020] (2) By controlling the type of algae, the extraction method and the cross-linking process parameters, the algae-based vegan leather of the present invention has good adaptability and can adjust its thickness, color, hardness and other characteristics according to different needs to meet the needs of various fields such as fashion, automobiles, furniture and other uses.

[0021] (3) Through the innovative application of the dual-network gel system, the algae-based vegan leather of the present invention has excellent mechanical strength and flexibility, and can maintain excellent performance in a variety of environments. Compared with traditional leather, its feel, strength and elasticity are not inferior, and it can meet the needs of different application scenarios.

[0022] (4) The algae-based vegan leather of this invention adopts a simple and low-cost production process. By optimizing the extraction and cross-linking reaction of materials, efficient and large-scale production can be achieved. Compared with the high cost and complex process of traditional leather, algae-based vegan leather not only has a short production cycle, but also has a lower production cost.

[0023] (5) Drawing on the principle of traditional leather tanning with fat-replenishing, this invention introduces oily substances into the formula, which not only improves the flexibility of algae-based vegan leather but also effectively enhances its water resistance. Through this innovative method, the algae-based vegan leather of this invention maintains excellent hand feel and mechanical strength while exhibiting stronger moisture resistance, making it suitable for a wider range of applications and further improving its market competitiveness. Attached Figure Description

[0024] Figure 1 This is a photograph of an algae-based vegan leather based on a dual-network gel system.

[0025] Figure 2 Stress-strain curves of algae-based vegan leather prepared using different formulations based on a dual-network gel system. Detailed Implementation

[0026] Three embodiments of the present invention are given below to illustrate the invention in detail. It should be noted that the embodiments are only used to further explain the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above description of the present invention.

[0027] In the following embodiments, unless otherwise specified, all parts are by weight and all percentages are by weight percentages.

[0028] Example 1

[0029] Mix 30g of dried seaweed powder with 200mL of deionized water using a high-speed mixer until homogeneous, obtaining a slurry. Add 3g of xanthan gum to the slurry and continue stirring until completely dissolved. Then add 5g of edible oil and stir until homogeneous, ensuring thorough mixing of all components. Heat the solution to 50℃ and stir for 1 hour to ensure homogeneity and stability. Next, adjust the pH of the solution to 5.0 using a buffer solution to ensure optimal cross-linking efficiency of tannic acid. Then add 0.5g of tannic acid and stir slowly for 30 minutes to 1 hour until the solution reaches the desired viscosity.

[0030] The crosslinking solution was poured evenly into a mold to form a thin film, which was then crosslinked using a CaCl2 solution. The crosslinked film was then air-dried naturally in a humidity-controlled environment, with humidity maintained at 50%-60% to avoid over-drying. After drying, the film was gently washed with warm water to remove unreacted tannins and other byproducts, and then air-dried again to constant weight. Finally, the resulting algae-based vegan leather sample was pressed overnight at room temperature to prevent shrinkage.

[0031] Example 2

[0032] Mix 20g of dried algae powder with 180mL of deionized water and stir the mixture using a high-speed mixer until dissolved. Add 2g of xanthan gum and 3g of vegetable oil, and continue stirring until the solution is homogeneous. Add 1.5g of bacterial cellulose and continue stirring for 10 minutes to ensure complete dissolution. Heat the mixture to 60°C and stir for 1 hour. Adjust the pH of the solution to 4.8 using a buffer solution, add 0.4g of tannic acid, and continue stirring for 45 minutes to 1 hour to ensure the tannic acid reacts fully with the other components.

[0033] The cross-linked solution was poured into a mold to form a film, which was then cross-linked using a CaCl2 solution. The cross-linked film was then allowed to dry naturally at room temperature, maintaining a humidity of 50%. After drying, the film was washed with a dilute acetic acid solution to remove unreacted tannins. After washing, it was further dried until a constant weight was achieved, ultimately yielding a supple algae-based vegan leather.

[0034] Example 3

[0035] Mix 25g of algae-based raw material with 250mL of deionized water using a high-speed mixer to ensure complete dissolution. Add 3g of xanthan gum and 4g of mineral oil, and continue stirring until homogeneous. Then add 2g of bacterial cellulose and continue stirring for 15 minutes to ensure the solution is homogeneous and stable. Heat the solution to 55℃ and stir for 1 hour. Adjust the pH to 5.2 using a buffer solution, add 0.6g of tannic acid, and stir slowly for 60 minutes to ensure the solution reaches the desired viscosity and cross-linking degree.

[0036] The crosslinking solution was poured into a mold to form a film, which was then crosslinked using a CaCl2 solution. The crosslinked film was air-dried naturally at 50% humidity to prevent deformation. After drying, it was gently washed with warm water to remove unreacted tannins and other byproducts, and then air-dried to constant weight to obtain the final algae-based vegan leather sample.

Claims

1. A method for preparing an algal-based vegan leather based on a double network gel system, the preparation features as follows: (1) Sodium alginate, xanthan gum, and oily substance A are sequentially added to water and stirred thoroughly to obtain a film-forming solution; the mass ratio of xanthan gum to sodium alginate is (0.1-2):1; (2) Crosslinking agent B is dissolved in deionized water and slowly added to the film-forming solution while stirring to ensure uniform distribution of the crosslinking agent throughout the solution; a buffer solution is used to adjust the pH of the film-forming solution to 3.5-10.5, and the temperature is controlled at 40-60°C to ensure optimal crosslinking efficiency; (3) The crosslinked solution is uniformly poured into a mold to form a thin film, which is then immersed in a CaCl2 solution for crosslinking, followed by repeated washing; the mass fraction of the CaCl2 solution is 1-20%; (4) The crosslinked film is naturally air-dried in a humidity-controlled environment, with the temperature controlled at 10-150°C and the humidity controlled at 50-100% to maintain the flexibility of the film; (5) After drying, the film is gently washed with warm water or dilute acetic acid solution to remove unreacted crosslinking agent B, and then air-dried at room temperature to constant weight to maintain the flexibility and moderate humidity of the film.

2. A process for the preparation of algal based vegan leather based on dual network gel system as claimed in claim 1, wherein The oily substance A used in (1) is one or more of plant oil, mineral oil, edible oil, olive oil, soybean oil, corn oil, rapeseed oil, coconut oil, or a mixture thereof.

3. A process for the preparation of algal based vegan leather based on dual network gel system as claimed in claim 1, wherein The crosslinking agent B used in (2) is one or more of tannic acid, phenolic compounds, divalent metal salts, glutaraldehyde, pentanediol, or a mixture thereof.

4. A process for the preparation of algal based vegan leather based on dual network gel system as claimed in claim 1, wherein The amount of crosslinking agent A added is 0.1-5% of the total mass of xanthan gum and sodium alginate.

5. A process for the preparation of algal based vegan leather based on dual network gel system as claimed in claim 1, wherein The film drying time is 6-96 hours until constant weight is achieved.

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