Natural rubber antibacterial film with photothermal conversion performance and preparation method

Abstract

The invention discloses a natural rubber antibacterial film with photothermal conversion performance and a preparation method thereof, and the specific method comprises the following steps: firstly preparing paint oil emulsion under the assistance of saponin and Tween-80, then uniformly mixing honey, fulvic acid and the paint oil emulsion, adjusting the pH value by using an alkaline solution, then adding a mixed solution of natural latex, saponin and Tween-80, and uniformly stirring to obtain the natural rubber antibacterial film with photothermal conversion performance. Finally, the natural rubber antibacterial film with the photo-thermal conversion performance is obtained through a pouring film forming method and a drying oven drying method. The method is ingenious in conception and simple in process and operation, uniform distribution of components in the film is promoted by means of the encapsulation wrapping effect of the surfactant and the high viscosity of the honey, the film is endowed with the antibacterial performance by means of the lacquer and the honey, and the film is endowed with the photothermal conversion performance by means of the fulvic acid and the honey; the problems that a single natural rubber material is poor in antibacterial property and poor in photothermal conversion performance are effectively solved. The main raw materials in the natural rubber film are high in safety, wide in source and low in price, so that the application range of the film is wide.

Description

Technical Field

[0001] The present invention belongs to the field of materials, and in particular relates to a natural rubber antibacterial film with light-to-heat conversion performance and a preparation method thereof. Background Art

[0002] Natural rubber latex is a milky white, viscous liquid derived from rubber trees, primarily composed of cis-1,4-polyisoprene rubber particles. Natural rubber exhibits excellent elasticity, mechanical properties, flexibility, and low thermal conductivity, making it widely used as a personal protective material. However, due to its content of plant proteins and carbohydrates, natural rubber alone is susceptible to mold and bacterial growth. Furthermore, natural rubber cannot effectively absorb and convert light energy into heat, making it difficult to achieve intelligent heating and insulation under light conditions. These functional limitations limit its application in daily life and medicine. Summary of the Invention

[0003] The purpose of the present invention is to address the problems existing in single natural rubber materials and provide a method for preparing a natural rubber antibacterial film with light-to-heat conversion performance and a natural rubber film prepared by the method.

[0004] To achieve the purpose of the present invention, the inventors, based on the disclosed natural rubber modification method, intend to use natural products lacquer oil and fulvic acid to give natural rubber antibacterial properties and photothermal conversion properties, respectively. Since adding lacquer oil is the main measure to enhance the antibacterial properties of natural rubber, the inventors first explored the blending characteristics of natural latex and lacquer oil, and found that stratification will occur after natural latex and lacquer oil are blended, and the lacquer oil will also solidify into blocks under normal temperature conditions. In order to solve the problem of stratification of natural latex and lacquer oil, the inventors have conducted in-depth research on the emulsification technology of lacquer oil and found that under the synergistic solubilization of two surfactants, saponin and Tween-80, lacquer oil can form an oil-in-water emulsion, and the emulsion of lacquer oil and natural latex can be uniformly blended under low temperature conditions and exist stably for a long time at room temperature. Since adding fulvic acid is the main measure to give natural rubber photothermal conversion properties, the inventors then explored the blending characteristics of natural latex and fulvic acid and found that the dispersion stability of natural latex deteriorates during the blending process, which is manifested as flocculation and precipitation of rubber particles. In order to solve the problem of rubber particle flocculation during the blending process of natural rubber latex and fulvic acid, the inventors explored a method of using an alkaline solution to convert fulvic acid into salt and simultaneously increase the pH value of the fulvic acid solution. They finally found that this process combination can ensure the uniform blending of natural rubber latex and fulvic acid at room temperature and their long-term stable existence.

[0005] Because the molecular size and structure of rubber particles differ from those of lacquer oil and fulvic acid, their fluidity and surface tension differ greatly. Therefore, during the film formation process of the blended solution of natural rubber latex, lacquer oil and fulvic acid, the lacquer oil and fulvic acid migrate to the film surface faster than the rubber particles, resulting in a much higher content of lacquer oil and fulvic acid on the film surface than inside the film. Excessive accumulation of honey and fulvic acid on the surface of the natural rubber film not only affects the mechanical properties of the film, but also causes the lacquer oil and fulvic acid on the film surface to be easily lost, resulting in the film's antibacterial properties and photothermal conversion performance being unsustainable and unstable. To solve this problem, the inventors first explored a method of using honey with high viscosity to prevent the migration of lacquer oil and fulvic acid to the film surface. Then, under the high temperature and high pressure microenvironment generated by ultrasonic cavitation, the emulsifying effect of saponin and Tween-80 was used to achieve uniform mixing of natural rubber particles, lacquer oil, fulvic acid and honey, preparing a small, uniformly distributed emulsion. This promoted the synchronous migration of natural rubber particles, lacquer oil, fulvic acid and honey during the film formation process, resulting in a natural rubber film with uniform composition distribution at different locations. In addition, by regulating the content of lacquer oil, honey and fulvic acid, the continuity and density of the natural rubber membrane are ensured, and the loss of lacquer oil, honey and fulvic acid on the membrane surface is effectively prevented, thereby obtaining a natural rubber membrane with long-lasting antibacterial properties and stable photothermal conversion properties.

[0006] The present invention provides a natural rubber antibacterial film with light-to-heat conversion performance, characterized in that: per gram of the film, the natural rubber particle content is 433-601 mg, the honey content is 168-256 mg, the fulvic acid content is 125-184 mg, and the lacquer oil content is 75-155 mg. After irradiation with simulated sunlight at 1000 W / m² for 5 minutes, the temperature of the film rises by 3-8°C. The film has an inhibitory effect on Staphylococcus aureus, Escherichia coli, and Aspergillus niger.

[0007] To solve the above technical problems, the technical solution of the present invention is: a method for preparing a natural rubber antibacterial film with light-to-heat conversion performance, the process steps and conditions of the method are as follows: 1) Preparation of a varnish emulsion: Melt 3–8 g of varnish at 80°C to form a liquid. Slowly add 0.5–1 g of saponin, 0.5–1 g of Tween-80, and 5 g of distilled water. Stir in a high-shear homogenizer for 5–10 min at a speed of 8000–12000 r / min. Then, add 5 g of distilled water at a speed of 2000–3000 r / min and mix thoroughly to obtain a varnish emulsion. 2) Prepare a mixed solution of honey, fulvic acid, and lacquer oil: Mix 10–20 g of honey, 5–10 g of fulvic acid, and 10 g of distilled water at 30°C and a stirring speed of 1000–2000 r / min for 10 minutes. Slowly add the lacquer oil emulsion, and adjust the pH of the mixed solution of honey, fulvic acid, and lacquer oil to 10–11 with an alkaline solution. 3) Preparation of natural rubber film: 40 g of natural rubber latex, 0.5–1 g of saponin, 0.5–1 g of Tween-80, and 15–20 g of distilled water were mixed at 30°C and a stirring speed of 500–1000 r / min for 5 min. Then, a mixed solution of honey, fulvic acid, and lacquer oil was slowly added. After mixing evenly, the mixture was ultrasonically treated at 28 kHz and 500 W for 15–25 min. The mixed solution was cast into a film and then dried in an oven at 60°C to obtain a natural rubber antibacterial film with photothermal conversion properties.

[0008] The method for preparing the natural rubber antibacterial film with light-to-heat conversion performance is characterized in that the saponin in step 1) and step 3) is one of soybean saponin, tea saponin and saponin.

[0009] The technical solution for preparing a natural rubber antibacterial film with photothermal conversion performance provided by the present invention cleverly utilizes saponin, a natural product with long-lasting foaming properties, and Tween-80, which has good emulsification and solubilization capabilities. First, through the synergistic effect of saponin and Tween-80, an emulsion of lacquer oil is prepared, and the emulsion can exist stably for a long time at room temperature, avoiding the separation of the oil phase and the aqueous phase. Secondly, by utilizing the ability of saponin and Tween-80 to reduce surface tension and form micelles, the encapsulation of natural rubber particles, lacquer oil, fulvic acid and honey is achieved, and the synchronous migration of these four substances during the film-forming process is promoted, thereby ensuring the uniformity of the composition at different positions in the natural rubber film and avoiding differences in the performance of the natural rubber film caused by uneven distribution of components.

[0010] The technical solution for preparing a natural rubber antibacterial film with photothermal conversion performance provided by the present invention also cleverly utilizes the natural product honey. First, the high viscosity of honey is used to prevent the rapid migration of lacquer oil and fulvic acid during the film formation process, thereby promoting uniform distribution of components in the natural rubber film. Secondly, the catalytic effect of glucose oxidase in honey is utilized to convert glucose into gluconic acid while generating hydrogen peroxide. This not only helps to enhance the antibacterial properties of the natural rubber film, but also improves the photothermal conversion efficiency of fulvic acid, thereby improving the photothermal conversion performance of the natural rubber film.

[0011] The present invention also has the following advantages: 1. The method provided by the present invention is ingenious in conception, simple in process and operation, and the main equipment used is a high-shear homogenizing emulsifying disperser, an ultrasonic device and an oven, which are all commonly used laboratory equipment and do not require additional investment.

[0012] 2. The natural rubber antibacterial film with photothermal conversion performance prepared by the method provided by the present invention not only retains the advantages of good stress-strain properties of natural rubber, but also gives the natural rubber material good antibacterial properties and intelligent heating performance under light conditions. Therefore, this type of new natural rubber material can not only be used as personal thermal management protection in daily life, but also can be used for photothermal therapy in the auxiliary medical field, and has good market prospects.

[0013] 3. Since the materials used in the method provided by the present invention—saponin, natural rubber latex, lacquer oil, honey, and fulvic acid—are all conventional chemical materials derived from natural plant, animal, and mineral resources, the materials are widely available and safe. Tween-80 is a conventional surfactant with low procurement costs, resulting in a low-cost preparation of the natural rubber antibacterial film with photothermal conversion properties. DETAILED DESCRIPTION

[0014] The following examples are given to illustrate the present invention in more detail. It is necessary to point out that the following examples are not to be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention. Example 1

[0015] 1) Preparation of a varnish emulsion: 3 g of varnish was melted at 80°C to form a liquid. 0.5 g of tea saponin, 0.5 g of Tween-80, and 5 g of distilled water were slowly added. The mixture was stirred at 8000 r / min in a high-shear homogenizer for 5 min. Then, 5 g of distilled water was added at 2000 r / min and mixed thoroughly to obtain a varnish emulsion. 2) Prepare a mixed solution of honey, fulvic acid, and lacquer oil: Mix 10 g of honey, 5 g of fulvic acid, and 10 g of distilled water at 30°C and 1000 r / min for 10 minutes. Then, slowly add the lacquer oil emulsion. Then, adjust the pH of the mixed solution of honey, fulvic acid, and lacquer oil to 10 with an alkaline solution. 3) Preparation of natural rubber film: 40 g of natural rubber latex, 0.8 g of tea saponin, 0.8 g of Tween-80, and 15 g of distilled water were mixed at 30°C and a stirring speed of 500 r / min for 5 min. Then, a mixed solution of honey, fulvic acid, and lacquer oil was slowly added. After mixing evenly, the mixture was treated with ultrasound at 28 kHz and 500 W for 15 min. The mixed solution was cast into a film and then dried in an oven at 60°C to obtain a natural rubber antibacterial film with photothermal conversion properties.

[0016] The membrane is yellow-brown in color. Per gram of membrane, it contains 601 mg of natural rubber particles, 168 mg of honey, 125 mg of fulvic acid, and 75 mg of lacquer oil. The membrane exhibits a tensile strength of 10.6 MPa and an elongation at break of 505%, demonstrating good tensile stress-strain properties. After irradiation with simulated sunlight at 1000 W / m² for 5 minutes, the membrane's temperature rises by 3.0°C. After irradiation is stopped, the temperature returns to its pre-irradiation level within 2 minutes, indicating that the membrane has good photothermal conversion properties, capable of converting light energy into thermal energy and exhibiting intelligent temperature-increasing properties under illumination. The inhibition zones of a 10 mm diameter membrane against Staphylococcus aureus, Escherichia coli, and Aspergillus niger are 11.2 mm, 12.7 mm, and 18.4 mm, respectively, indicating that the membrane effectively inhibits the growth of microorganisms on the membrane surface and in its surroundings, demonstrating its antibacterial properties. Example 2

[0017] 1) Preparation of a varnish emulsion: 5 g of varnish was melted at 80°C to form a liquid. Then, 0.5 g of soybean saponin, 0.8 g of Tween-80, and 5 g of distilled water were slowly added. The mixture was stirred at 12,000 r / min in a high-shear homogenizer for 8 min. Subsequently, 5 g of distilled water was added at 3,000 r / min and mixed thoroughly to obtain a varnish emulsion. 2) Prepare a mixed solution of honey, fulvic acid, and lacquer oil: Mix 20 g of honey, 10 g of fulvic acid, and 10 g of distilled water at 30°C and 1000 r / min for 10 minutes. Then, slowly add the lacquer oil emulsion. Then, adjust the pH of the mixed solution of honey, fulvic acid, and lacquer oil to 11 with an alkaline solution. 3) Preparation of natural rubber film: 40 g of natural rubber latex, 1 g of soybean saponin, 0.8 g of Tween-80, and 20 g of distilled water were mixed at 30°C and a stirring speed of 1000 r / min for 5 min. Then, a mixed solution of honey, fulvic acid, and lacquer oil was slowly added. After mixing evenly, the mixture was treated with ultrasound at 28 kHz and 500 W for 25 min. The mixed solution was cast into a film and then dried in an oven at 60°C to obtain a natural rubber antibacterial film with photothermal conversion properties.

[0018] The membrane is yellow-brown in color. Per gram of membrane, it contains 441 mg of natural rubber particles, 256 mg of honey, 184 mg of fulvic acid, and 92 mg of lacquer oil. The membrane exhibits a tensile strength of 8.7 MPa and an elongation at break of 420%, demonstrating excellent tensile stress-strain properties. After irradiation with simulated sunlight at 1000 W / m² for 5 minutes, the membrane's temperature rises by 8.0°C. After irradiation is stopped, the temperature returns to its pre-irradiation level within 7 minutes, indicating excellent photothermal conversion performance. The membrane can convert light energy into thermal energy and exhibits intelligent temperature-increasing properties under illumination. The inhibition zones of a 10 mm diameter membrane against Staphylococcus aureus, Escherichia coli, and Aspergillus niger are 12.8 mm, 13.9 mm, and 19.3 mm, respectively, demonstrating that the membrane effectively inhibits the growth of microorganisms on the membrane surface and in its surroundings, demonstrating its antibacterial properties. Example 3

[0019] 1) Preparation of a varnish emulsion: 8 g of varnish was melted at 80°C to form a liquid. Then, 1 g of saponin, 1 g of Tween-80, and 5 g of distilled water were slowly added. The mixture was stirred at 10,000 r / min in a high-shear homogenizer for 10 min. Subsequently, 5 g of distilled water was added at 3,000 r / min and mixed thoroughly to obtain a varnish emulsion. 2) Prepare a mixed solution of honey, fulvic acid, and lacquer oil: Mix 15 g of honey, 8 g of fulvic acid, and 10 g of distilled water at 30°C and 2000 r / min for 10 minutes. Then, slowly add the lacquer oil emulsion. Then, adjust the pH of the mixed solution of honey, fulvic acid, and lacquer oil to 10.5 with an alkaline solution. 3) Preparation of natural rubber film: 40 g of natural rubber latex, 1 g of saponin, 1 g of Tween-80, and 18 g of distilled water were mixed at 30°C and a stirring speed of 800 r / min for 5 min. Then, a mixed solution of honey, fulvic acid, and lacquer oil was slowly added. After mixing evenly, the mixture was treated with ultrasound at 28 kHz and 500 W for 18 min. The mixed solution was cast into a film and then dried in an oven at 60°C to obtain a natural rubber antibacterial film with photothermal conversion properties.

[0020] The membrane is yellow-brown in color. Per gram of membrane, it contains 465 mg of natural rubber particles, 198 mg of honey, 155 mg of fulvic acid, and 155 mg of lacquer oil. The membrane exhibits a tensile strength of 9.4 MPa and an elongation at break of 449%, demonstrating excellent tensile stress-strain properties. After irradiation with simulated sunlight at 1000 W / m² for 5 minutes, the membrane's temperature rises by 5.7°C. After irradiation is stopped, the temperature returns to its pre-irradiation level within 5 minutes, indicating excellent photothermal conversion performance. The membrane can convert light energy into thermal energy and exhibits intelligent temperature-increasing properties under illumination. The inhibition zones of a 10 mm diameter membrane against Staphylococcus aureus, Escherichia coli, and Aspergillus niger are 14.3 mm, 16.0 mm, and 21.2 mm, respectively, demonstrating that the membrane effectively inhibits the growth of microorganisms on the membrane surface and in its surroundings, demonstrating its antibacterial properties. Example 4

[0021] 1) Preparation of a varnish emulsion: 6 g of varnish was melted at 80°C to form a liquid. 0.8 g of saponin, 0.5 g of Tween-80, and 5 g of distilled water were slowly added. The mixture was stirred at 12,000 r / min in a high-shear homogenizer for 9 min. Subsequently, 5 g of distilled water was added at 2,500 r / min and mixed thoroughly to obtain a varnish emulsion. 2) Prepare a mixed solution of honey, fulvic acid, and lacquer oil: Mix 18 g of honey, 9 g of fulvic acid, and 10 g of distilled water at 30°C and 1500 r / min for 10 minutes. Then, slowly add the lacquer oil emulsion. Then, adjust the pH of the mixed solution of honey, fulvic acid, and lacquer oil to 11 with an alkaline solution. 3) Preparation of natural rubber film: 40 g of natural rubber latex, 1 g of saponin, 0.5 g of Tween-80, and 20 g of distilled water were mixed at 30°C and a stirring speed of 600 r / min for 5 min. Then, a mixed solution of honey, fulvic acid, and lacquer oil was slowly added. After mixing evenly, the mixture was treated with ultrasound at 28 kHz and 500 W for 23 min. The mixed solution was cast into a film and then dried in an oven at 60°C to obtain a natural rubber antibacterial film with photothermal conversion properties.

[0022] The membrane is yellow-brown in color. Per gram of membrane, it contains 454 mg of natural rubber particles, 235 mg of honey, 170 mg of fulvic acid, and 113 mg of lacquer oil. The membrane exhibits a tensile strength of 9.0 MPa and an elongation at break of 431%, demonstrating good tensile stress-strain properties. After irradiation with simulated sunlight at 1000 W / m² for 5 minutes, the membrane's temperature rises by 7.1°C. After irradiation is stopped, the temperature returns to its pre-irradiation level within 6 minutes, indicating that the membrane has good photothermal conversion properties, capable of converting light energy into thermal energy and exhibiting intelligent temperature-increasing properties under illumination. The inhibition zones of a 10 mm diameter membrane against Staphylococcus aureus, Escherichia coli, and Aspergillus niger are 13.6 mm, 15.3 mm, and 20.5 mm, respectively, indicating that the membrane effectively inhibits the growth of microorganisms on the membrane surface and in its surroundings, demonstrating its antibacterial properties. Example 5

[0023] 1) Preparation of a varnish emulsion: 4 g of varnish was melted at 80°C to form a liquid. 0.5 g of soybean saponin, 0.5 g of Tween-80, and 5 g of distilled water were slowly added. The mixture was stirred at 9000 r / min in a high-shear homogenizer for 6 min. Subsequently, 5 g of distilled water was added at 2500 r / min and mixed thoroughly to obtain a varnish emulsion. 2) Prepare a mixed solution of honey, fulvic acid, and lacquer oil: Mix 12 g of honey, 6 g of fulvic acid, and 10 g of distilled water at 30°C and 1500 r / min for 10 minutes. Then, slowly add the lacquer oil emulsion. Then, adjust the pH of the mixed solution of honey, fulvic acid, and lacquer oil to 11 with an alkaline solution. 3) Preparation of natural rubber film: 40 g of natural rubber latex, 0.5 g of soybean saponin, 1 g of Tween-80, and 15 g of distilled water were mixed at 30°C and a stirring speed of 1000 r / min for 5 min. Then, a mixed solution of honey, fulvic acid, and lacquer oil was slowly added. After mixing evenly, the mixture was treated with ultrasound at 28 kHz and 500 W for 20 min. The mixed solution was cast into a film and then dried in an oven at 60°C to obtain a natural rubber antibacterial film with photothermal conversion properties.

[0024] The membrane is yellow-brown in color. Per gram of membrane, it contains 553 mg of natural rubber particles, 187 mg of honey, 138 mg of fulvic acid, and 92 mg of lacquer oil. The membrane exhibits a tensile strength of 9.8 MPa and an elongation at break of 475%, demonstrating excellent tensile stress-strain properties. After irradiation with simulated sunlight at 1000 W / m² for 5 minutes, the membrane's temperature rises by 3.8°C. After irradiation is stopped, the temperature returns to its pre-irradiation level within 3 minutes, indicating excellent photothermal conversion performance. The membrane can convert light energy into thermal energy and exhibits intelligent temperature-increasing properties under illumination. The inhibition zones of a 10 mm diameter membrane against Staphylococcus aureus, Escherichia coli, and Aspergillus niger are 11.9 mm, 13.1 mm, and 18.8 mm, respectively, demonstrating that the membrane effectively inhibits the growth of microorganisms on the membrane surface and in its surroundings, demonstrating its antibacterial properties. Example 6

[0025] 1) Preparation of a varnish emulsion: 8 g of varnish was melted at 80°C to form a liquid. Then, 1 g of tea saponin, 1 g of Tween-80, and 5 g of distilled water were slowly added. The mixture was stirred at 11,000 r / min in a high-shear homogenizer for 10 min. Subsequently, 5 g of distilled water was added at 3,000 r / min and mixed thoroughly to obtain a varnish emulsion. 2) Prepare a mixed solution of honey, fulvic acid, and lacquer oil: Mix 20 g of honey, 8 g of fulvic acid, and 10 g of distilled water at 30°C and 2000 r / min for 10 minutes. Then, slowly add the lacquer oil emulsion. Then, adjust the pH of the mixed solution of honey, fulvic acid, and lacquer oil to 10.5 with an alkaline solution. 3) Preparation of natural rubber film: 40 g of natural rubber latex, 1 g of tea saponin, 1 g of Tween-80, and 20 g of distilled water were mixed at 30°C and a stirring speed of 900 r / min for 5 min. Then, a mixed solution of honey, fulvic acid, and lacquer oil was slowly added. After mixing evenly, the mixture was treated with ultrasound at 28 kHz and 500 W for 20 min. The mixed solution was cast into a film and then dried in an oven at 60°C to obtain a natural rubber antibacterial film with photothermal conversion properties.

[0026] The membrane is yellow-brown in color. Per gram of membrane, it contains 433 mg of natural rubber particles, 251 mg of honey, 144 mg of fulvic acid, and 144 mg of lacquer oil. The membrane exhibits a tensile strength of 8.2 MPa and an elongation at break of 395%, demonstrating excellent tensile stress-strain properties. After irradiation with simulated sunlight at 1000 W / m² for 5 minutes, the membrane's temperature rises by 4.5°C. After irradiation is stopped, the temperature returns to its pre-irradiation level within 4 minutes, indicating excellent photothermal conversion performance. The membrane can convert light energy into thermal energy and exhibits intelligent temperature-increasing properties under illumination. The inhibition zones of a 10 mm diameter membrane against Staphylococcus aureus, Escherichia coli, and Aspergillus niger are 15.6 mm, 18.1 mm, and 21.6 mm, respectively, indicating that the membrane effectively inhibits the growth of microorganisms on the membrane surface and in its surroundings, demonstrating its antibacterial properties.

Claims

1. A natural rubber antibacterial film with light-to-heat conversion performance, characterized in that: The content of natural rubber particles in each gram of film is 433-601 mg, honey content is 168-256 mg, fulvic acid content is 125-184 mg, and lacquer oil content is 75-155 mg. After irradiation with simulated sunlight at 1000 W / m² for 5 minutes, the temperature of the film rises by 3-8°C. The film has inhibitory effects on Staphylococcus aureus, Escherichia coli, and Aspergillus niger.

2. A method for preparing the natural rubber antibacterial film with light-to-heat conversion performance according to claim 1, the process steps and conditions of the method are as follows: 1) Preparation of a varnish emulsion: Melt 3–8 g of varnish at 80°C to form a liquid. Slowly add 0.5–1 g of saponin, 0.5–1 g of Tween-80, and 5 g of distilled water. Stir in a high-shear homogenizer for 5–10 min at a speed of 8000–12000 r / min. Then, add 5 g of distilled water at a speed of 2000–3000 r / min and mix thoroughly to obtain a varnish emulsion. 2) Prepare a mixed solution of honey, fulvic acid, and lacquer oil: Mix 10–20 g of honey, 5–10 g of fulvic acid, and 10 g of distilled water at 30°C and a stirring speed of 1000–2000 r / min for 10 minutes. Slowly add the lacquer oil emulsion, and adjust the pH of the mixed solution of honey, fulvic acid, and lacquer oil to 10–11 with an alkaline solution. 3) Preparation of natural rubber film: 40 g of natural rubber latex, 0.5–1 g of saponin, 0.5–1 g of Tween-80, and 15–20 g of distilled water were mixed at 30°C and a stirring speed of 500–1000 r / min for 5 min. Then, a mixed solution of honey, fulvic acid, and lacquer oil was slowly added. After mixing evenly, the mixture was ultrasonically treated at 28 kHz and 500 W for 15–25 min. The mixed solution was cast into a film and then dried in an oven at 60°C to obtain a natural rubber antibacterial film with photothermal conversion properties.

3. The method for preparing a natural rubber antibacterial film with light-to-heat conversion performance according to claim 2, wherein the saponin used in the method is one of soybean saponin, tea saponin and saponin.