Degradable waterproof heat-insulating antibacterial lunch box and preparation method thereof

Abstract

The application provides a degradable waterproof heat-insulating antibacterial lunch box and a preparation method thereof, and relates to the field of lunch boxes. Raw materials are as follows in terms of weight parts: 20-30 parts of wheat straw, 20-30 parts of corn straw, 10-20 parts of reed, 10-20 parts of cork, and 5-10 parts of starch glue. The degradable waterproof heat-insulating antibacterial lunch box uses wheat straw, corn straw, reed, cork and starch glue as raw materials, can achieve the functions of waterproofing, degradability, heat preservation and antibiosis under the premise of ensuring normal use strength, and will not cause environmental pollution. The cork not only brings good waterproof effect to the lunch box, but also effectively isolates external temperature and maintains the temperature of food due to its unique structure. The reed and the cork also have natural antibacterial and mildew-proof effects, and can effectively maintain the freshness and health safety of food.

Description

Technical Field

[0001] This application relates to the field of lunch boxes, and more particularly to a biodegradable, waterproof, heat-insulating, and antibacterial lunch box and its preparation method. Background Technology

[0002] Straw refers to the stalks and stems of crops that remain in the fields after harvesting. It mainly consists of the stems and leaves of crops such as rice straw, wheat straw, and corn stalks. According to statistics from the Ministry of Agriculture and Rural Affairs, the total amount of straw produced by major crops such as corn, rice, wheat, rapeseed, soybeans, and cotton in China is 865 million tons, of which 731 million tons are collectable. The emergence of disposable lunch boxes made from crop straw not only solves the rapidly growing demand for disposable lunch boxes in my country, but also addresses the environmental pollution problem caused by large amounts of straw.

[0003] However, disposable food containers made from crop straw on the market often have poor waterproof properties and need to be waterproofed. While adding resin can improve the waterproof performance of straw food containers, the production process of these synthetic resins is very complex, and the synthetic resins left inside the food containers cannot be degraded. Summary of the Invention

[0004] The purpose of this application is to provide a biodegradable, waterproof, heat-insulating, and antibacterial lunch box and its preparation method to solve the above-mentioned problems.

[0005] To achieve the above objectives, the first aspect of this application provides a biodegradable, waterproof, heat-insulating, and antibacterial lunch box, the raw materials of which, by weight, include: 20-30 parts wheat straw, 20-30 parts corn straw, 10-20 parts reeds, 10-20 parts cork, and 5-10 parts starch glue.

[0006] A second aspect of this application provides a method for preparing the aforementioned biodegradable, waterproof, heat-insulating, and antibacterial lunch box, comprising: The wheat straw, corn straw, reeds and starch glue are mixed to obtain a mixture. The mixture is hot-pressed, cooled, and demolded to obtain the biodegradable, waterproof, heat-insulating, and antibacterial lunch box.

[0007] Optionally, the wheat straw and the corn straw are first steamed or boiled before use.

[0008] Optionally, the temperature of the first cooking is 100℃-120℃, the time is 0.5h-1.0h, and the pressure is 0.4Mpa-0.6Mpa.

[0009] Optionally, the cork is subjected to a second steaming and a first crushing process before use.

[0010] Optionally, the temperature of the second cooking is 100℃-120℃, and the time is 1.0h-1.5h.

[0011] Optionally, the particle size of the cork after the first crushing is 0.25cm-0.425cm.

[0012] Optionally, the method for preparing the biodegradable, waterproof, heat-insulating, and antibacterial lunch box satisfies at least one of the following conditions: A. The reeds are subjected to a second crushing before use; B. The beating degree of the mixture is 23°SR-26°SR.

[0013] Optionally, the particle size of the second crushed reed is 0.355cm-0.425cm.

[0014] Optionally, the hot pressing temperature is 130℃-150℃ and the time is 2min-3min.

[0015] Compared with the prior art, the beneficial effects of this application include: The biodegradable, waterproof, heat-insulating, and antibacterial lunch box provided in this application uses wheat straw, corn straw, reeds, cork, and starch adhesive as raw materials. It does not use any waterproofing additives and achieves waterproof, biodegradable, heat-insulating, and antibacterial functions while ensuring normal strength, without causing environmental pollution. Cork not only provides excellent waterproofing but its unique structure also effectively insulates against external temperatures, maintaining food temperature. Reeds and cork also have natural antibacterial and anti-mildew effects, effectively maintaining food freshness and hygiene. Furthermore, it solves the problem of large-scale accumulation and unusable use of materials such as wheat straw, corn straw, and reeds, making it suitable for large-scale production and promotion.

[0016] The method for preparing the biodegradable, waterproof, heat-insulating, and antibacterial lunch box provided in this application is simple and has low production costs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0018] Figure 1 This is a picture of the biodegradable, waterproof, heat-insulating, and antibacterial lunch box prepared in Example 1. Detailed Implementation

[0019] As used in this article: "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0020] The conjunction "composed of" excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of" appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0021] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0022] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0023] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (where K is any number representing a multiplier). It is important to understand that, unlike parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0024] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0025] The first aspect of this application provides a biodegradable, waterproof, heat-insulating, and antibacterial lunch box, the raw materials of which, by weight, include: 20-30 parts wheat straw, 20-30 parts corn straw, 10-20 parts reeds, 10-20 parts cork, and 5-10 parts starch glue.

[0026] Optionally, the raw materials for the biodegradable, waterproof, heat-insulating, and antibacterial lunch box, by weight, may include: wheat straw (20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, or any value between 20 and 30 parts); corn straw (20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, or any value between 20 and 30 parts); and reeds (…). 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts or any value between 10 and 20 parts; cork can be 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts or any value between 10 and 20 parts; starch gum can be 5, 6, 7, 8, 9, 10 parts or any value between 5 and 10 parts.

[0027] It's important to note that cork cell walls consist of a layer of suberin, a thin middle layer containing cellulose, and a thicker thin layer composed of suberin and cork wax. Suberin is a complex mixture of fatty acids and organic alcohols, and it's the basic substance that prevents gases and liquids from penetrating the cork, giving cork excellent waterproof properties and very low water absorption. Furthermore, cork has a honeycomb structure with internal cavities, which slows heat diffusion from the material's interior to the exterior. This allows cork to both reduce internal heat loss and slow the penetration of external energy, providing excellent heat insulation and heat protection for biodegradable, waterproof, heat-insulating, and antibacterial food containers. Placing the container in a cold source for ten minutes only lowers the temperature by 8°C, while placing it in a heat source only raises the temperature by 7°C. The near-closed structure of cork cells results in extremely low hygroscopicity, and combined with the antibacterial activity of its main chemical component, cork resin, cork exhibits excellent anti-mildew properties.

[0028] It should also be noted that reed is a perennial herb belonging to the genus Miscanthus of the Poaceae family. The outer surface of the reed stem has a mineralized layer, with silica as its main component. Silica is nonpolar, making this mineralized layer hydrophobic. Furthermore, this mineralized layer on the outer surface of the reed stem also provides some protection against hydroxyl groups, allowing the reed to act as a waterproofing agent. In addition, the outer surface of the reed contains a large amount of hydrocarbons such as fatty acids, fats, and waxes, while its cellulose and hemicellulose content is very low, giving it a natural waterproof advantage. The rough surface of the reed provides good ventilation, and the silicon in its stems and leaves inhibits the growth of mold and bacteria. The silica in the reed dissolves in water to form a silicic acid solution, which also has a certain bactericidal effect on mold and bacteria.

[0029] A second aspect of this application provides a method for preparing the aforementioned biodegradable, waterproof, heat-insulating, and antibacterial lunch box, comprising: The wheat straw, corn straw, reeds and starch glue are mixed to obtain a mixture. The mixture is hot-pressed, cooled, and demolded to obtain the biodegradable, waterproof, heat-insulating, and antibacterial lunch box.

[0030] In some embodiments, dry wheat straw and dry corn straw are used as raw materials. Before use, the dry materials can be soaked to make them soft and malleable, and to remove dust and impurities.

[0031] In some embodiments, the wheat straw and the corn straw are first steamed or boiled before use.

[0032] It is important to note that the cellulose in straw is surrounded by lignin and hemicellulose, which makes the cellulose spatial structure complex and difficult to dissolve in water. The first cooking of wheat straw and corn straw can effectively extract the cellulose in the straw, increase the utilization rate of cellulose, enhance toughness, make it more plastic and easier to shape, which is convenient for subsequent processing.

[0033] In some embodiments, the temperature of the first cooking is 100℃-120℃, the time is 0.5h-1.0h, and the pressure is 0.4Mpa-0.6Mpa.

[0034] Optionally, the temperature of the first cooking can be any value between 100℃, 110℃, 120℃, or 100℃-120℃; the time can be any value between 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1.0h, or 0.5h-1.0h; and the pressure can be any value between 0.4Mpa, 0.5Mpa, 0.6Mpa, or 0.4Mpa-0.6Mpa.

[0035] In some embodiments, the cork is subjected to a second steaming and a first crushing process in sequence before use.

[0036] It is important to note that after the second steaming treatment, cork can effectively remove surface impurities and water-soluble substances, and the cork becomes smoother, which is beneficial for subsequent processing. Furthermore, since the pores on the surface of cork are lens-shaped channels, which are the main pathways for water to enter the cork, cork with high porosity usually has a higher water absorption rate, which is not conducive to the application of cork. After steaming treatment, the surface porosity of cork is reduced, which can effectively improve its waterproof performance.

[0037] It should also be noted that after cork is steamed, its cell structure becomes almost completely closed, and coupled with its extremely low hygroscopicity, it possesses excellent anti-mildew and antibacterial properties. The pores on the surface of cork are lens-like channels, which are the main pathways for water to enter the cork. Cork with high porosity usually has a higher water absorption rate, which is not conducive to the application of cork. After steaming, the porosity of cork is significantly reduced, which greatly helps to improve its waterproof performance. In addition, after steaming, the cork expands in volume, enhancing its elasticity and flexibility, and can remove impurities, which is beneficial for processing and utilization.

[0038] It should also be noted that breaking the cork into smaller pieces allows it to be distributed more evenly within the straw matrix, ensuring improved waterproofing throughout the entire food container. Additionally, breaking it into smaller particles increases its surface area, making the cork bond more tightly with the straw, improving overall integrity, and enhancing mechanical properties.

[0039] In some embodiments, the temperature of the second cooking is 100℃-120℃, and the time is 1.0h-1.5h.

[0040] Optionally, the temperature of the second cooking can be any value between 100℃, 110℃, 120℃ or 100℃-120℃, and the time can be any value between 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h or 1.0h-1.5h.

[0041] It should be noted that the porosity of the cork surface is reduced by about 30% during the second steaming process, which can effectively improve its waterproof performance.

[0042] In some embodiments, the particle size of the cork after the first crushing is 0.25cm-0.425cm.

[0043] Optionally, the particle size of the first crushed cork can be any value between 0.25cm, 0.3cm, 0.4cm, 0.425cm, or 0.25cm-0.425cm.

[0044] It is important to note that the cork particles should be kept within a reasonable range to ensure good mechanical properties and appearance. When the cork particle size is 0.25cm-0.425cm, the surface of the lunch box is smooth and flat with a delicate texture. The bending resistance and impact toughness of the material show a trend of first increasing and then decreasing as the size of the cork particles decreases. Particles within this range have excellent mechanical properties, and the lunch boxes made from them show good results in load tests according to standards.

[0045] In some embodiments, the method for preparing the biodegradable, waterproof, heat-insulating, and antibacterial lunch box satisfies at least one of the following conditions: A. The reeds are subjected to a second crushing before use; B. The beating degree of the mixture is 23°SR-26°SR.

[0046] Optionally, the beating degree of the mixture can be any value between 23°SR, 24°SR, 25°SR, 26°SR, or 23°SR-26°SR.

[0047] In some embodiments, the particle size of the second crushed reed is 0.355cm-0.425cm.

[0048] Optionally, the particle size of the second crushed reed can be any value between 0.355cm, 0.4cm, 0.425cm, or 0.355cm-0.425cm.

[0049] It's important to note that maintaining the reed particle size of 0.355cm-0.425cm balances good waterproof and mechanical properties, resulting in a smoother surface for the food container and a better user experience. This particle size also optimizes fiber extraction.

[0050] In some embodiments, the hot pressing temperature is 130℃-150℃ and the time is 2min-3min.

[0051] Optionally, the hot pressing temperature can be any value between 130℃, 140℃, 150℃ or 130℃-150℃, and the time can be any value between 2min, 2.5min, 3min or 2min-3min.

[0052] It should be noted that when the hot pressing temperature is 130℃-150℃ and the time is 2min-3min, the decomposition rate of cork is greatly accelerated, decomposing hydrophobic phenolic substances, which significantly enhances water resistance.

[0053] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0054] Example 1 This embodiment provides a biodegradable, waterproof, heat-insulating, and antibacterial lunch box, the raw materials of which, by weight, include: 20 parts wheat straw, 20 parts corn straw, 10 parts reeds, 10 parts cork, and 5 parts starch glue.

[0055] This embodiment provides a method for preparing a biodegradable, waterproof, heat-insulating, and antibacterial lunch box, including: S1: Soak dry wheat straw, dry corn straw, and dry reeds for 6 hours to make them soft and malleable, and to remove dust and impurities; S2: Place the soaked wheat straw and corn straw into a pressure cooker and cook them at a pressure of 0.4 MPa, a temperature of 120°C, and a time of 0.5 h to obtain the treated wheat straw and corn straw. S3: The naturally dried cork is placed in an electrically heated constant temperature stainless steel water bath for steaming. The temperature is set at 100℃ and the time is 1.0h to obtain the treated cork. S4: Crush the treated cork into small, soft pieces, then grind them into granules with a particle size of 0.425cm in a grinder; S5: Crush and grind the reeds to a particle size of 0.425cm; S6: Thoroughly mix the processed wheat straw, corn straw, crushed cork and reeds, and add starch glue to bind the raw materials together to obtain a mixture with a pulping degree of 25°SR. S7: Place the mixture into the mold of the hot pressing shaping equipment, set the hot pressing temperature to 150℃, and the hot pressing time to 2 minutes; S8: After hot pressing, the food is cooled and demolded under natural conditions to obtain a biodegradable, waterproof, heat-insulating, and antibacterial lunch box.

[0056] This biodegradable, waterproof, heat-insulating, and antibacterial lunch box, such as Figure 1 As shown.

[0057] Example 2 This embodiment provides a biodegradable, waterproof, heat-insulating, and antibacterial lunch box, the raw materials of which, by weight, include: 30 parts wheat straw, 30 parts corn straw, 20 parts reeds, 20 parts cork, and 10 parts starch glue.

[0058] This embodiment provides a method for preparing a biodegradable, waterproof, heat-insulating, and antibacterial lunch box, including: S1: Soak dry wheat straw, dry corn straw, and dry reeds for 6 hours to make them soft and malleable, and to remove dust and impurities; S2: Place the soaked wheat straw and corn straw into a pressure cooker and cook them at a pressure of 0.4 MPa, a temperature of 100℃, and a time of 1 hour to obtain the treated wheat straw and corn straw. S3: The naturally dried cork is placed in an electrically heated constant temperature stainless steel water bath for steaming. The temperature is set at 100℃ and the time is 1 hour to obtain the treated cork. S4: Crush the treated cork into small, soft pieces, then grind them into granules with a particle size of 0.355cm in a grinder; S5: Crush and grind the reeds to a particle size of 0.355cm; S6: Thoroughly mix the processed wheat straw, corn straw, crushed cork and reeds, and add starch glue to bind the raw materials together to obtain a mixture with a pulping degree of 25°SR. S7: Place the mixture into the mold of the hot pressing shaping equipment, set the hot pressing temperature to 150℃, and the hot pressing time to 2 minutes; S8: After hot pressing, the food is cooled and demolded under natural conditions to obtain a biodegradable, waterproof, heat-insulating, and antibacterial lunch box.

[0059] Example 3 This embodiment provides a biodegradable, waterproof, heat-insulating, and antibacterial lunch box, the raw materials of which, by weight, include: 25 parts wheat straw, 25 parts corn straw, 15 parts reeds, 15 parts cork, and 5 parts starch glue.

[0060] This embodiment provides a method for preparing a biodegradable, waterproof, heat-insulating, and antibacterial lunch box, including: S1: Wheat straw, corn straw, cork, and reeds are thoroughly mixed and treated, and starch glue is added to bind the raw materials together to obtain a mixture. The pulping degree of the mixture is 23°SR. S2: Place the mixture into the mold of the hot pressing shaping equipment, set the hot pressing temperature to 150℃, and the hot pressing time to 2 minutes; S3: After hot pressing, allow the food to cool and demold naturally to obtain a biodegradable, waterproof, heat-insulating, and antibacterial lunch box.

[0061] Comparative Example 1 This comparative example provides a lunch box and its preparation method. The difference between this comparative example and Example 1 is that no wheat straw is added, while other conditions are the same as in Example 1.

[0062] Comparative Example 2 This comparative example provides a lunch box and its preparation method. The difference between this comparative example and Example 1 is that no corn stalks are added, while other conditions are the same as in Example 1.

[0063] Comparative Example 3 This comparative example provides a lunch box and its preparation method. The difference between this comparative example and Example 1 is that no reeds are added, while other conditions are the same as in Example 1.

[0064] Comparative Example 4 This comparative example provides a lunchbox and its preparation method. The difference between this comparative example and Example 1 is that no cork is added, while other conditions are the same as in Example 1.

[0065] Comparative Example 5 This comparative example provides a lunch box and its preparation method. The difference between this comparative example and Example 1 is that no starch glue is added, while other conditions are the same as in Example 1.

[0066] Comparative Example 6 This comparative example provides a lunch box and its preparation method. The difference between this comparative example and Example 1 is that the raw materials of this comparative example, by weight, include: 15g of wheat straw, 15g of corn straw, 5g of reeds, 10g of cork, and 5g of starch glue. The preparation method of this comparative example is the same as that of Example 1.

[0067] Comparative Example 7 This comparative example provides a lunch box and its preparation method. The difference between this comparative example and Example 1 is that the hot pressing temperature in this comparative example is 100°C and the time is 1 min.

[0068] The lunch boxes prepared in Examples 1-3 and Comparative Examples 1-7 were tested for waterproofing, heat preservation, antibacterial properties, and biodegradability.

[0069] Waterproof test: Water absorption test: Place warm water (25℃±1℃) inside the food container and incubate it in a constant temperature incubator for 1 hour. Measure its weight before and after the water absorption test.

[0070] Calculate the water absorption rate using the formula: WA = (m2 - m1) / m1; WA represents the water absorption rate (%), m1 represents the mass of the lunchbox before it was put into water (kg), and m2 represents the mass of the lunchbox after it was put into water (kg).

[0071] Insulation test: Place the lunchbox in a cold environment (10℃±1℃) for 10 minutes, and use a thermometer to measure the initial surface temperature and the temperature change. Place the lunchbox in a heat source environment (50℃±1℃) for 10 minutes, and use a thermometer to measure the initial surface temperature and the temperature change.

[0072] Antimicrobial test: The lunch box was cut into small pieces suitable for testing. First, it was sterilized using a high-temperature, high-pressure method. The surface of the sterilized sample was then inoculated with the appropriate bacterial strain. The inoculated sample was placed in a petri dish and kept at a suitable ambient temperature for 24 hours. The surface area of ​​the specimen was observed, and its damage value was assessed. The damage assessment criteria are shown in Table 1.

[0073] Table 1 Victim Assessment Criteria

[0074] Biodegradability test: The weight change of the food container in the soil was tested, and the weight loss rate from day 7 to day 21 was recorded.

[0075] The test results for the above waterproof, heat insulation, antibacterial and degradable tests are shown in Table 2.

[0076] Table 2 Performance Tests

[0077] As can be seen from the above test results, the biodegradable waterproof, heat-insulating and antibacterial lunch boxes prepared in Examples 1-3 of this application are made of natural materials, are green and pollution-free, and can be biodegraded in nature; they meet the requirements of GB / T 18006.3-2020 General Technical Requirements for Disposable Biodegradable Tableware, which stipulates that the lunch boxes can be soaked in hot water at 95℃±5℃ for 30 minutes without deformation, peeling, wrinkling and other phenomena.

[0078] The reduction of absorbent materials in Comparative Examples 1-2 resulted in a decrease in water absorption rate. The presence of cork and reeds did not significantly alter temperature and antibacterial properties. The reduction in materials increased the degree of biodegradability.

[0079] In Comparative Example 3, without the addition of reeds, the water absorption rate increased. However, due to the presence of cork, the increase in water absorption rate was limited. This indicates that the waterproof effect of cork is better than that of reeds, but the values ​​differ from those in Example 1. This suggests that the addition of reeds can further enhance the waterproof effect. Cork still maintains a good heat insulation effect. The absence of reeds causes a slight increase in temperature. The absence of reeds also reduces the antibacterial effect. The reduction in material increases the biodegradability.

[0080] In Comparative Example 4, without the addition of cork, the water absorption rate increased significantly, with only reeds showing a waterproof effect. The temperature rise and fall were also significant. This is because cork is the main heat insulation material for the lunch box, with a damage value of 1, resulting in a poorer antibacterial effect. Both cork and reeds have anti-mold effects and increased biodegradability.

[0081] Comparative Example 5 did not contain any starch adhesive. The starch adhesive mainly serves as a binder. When the lunch boxes in Comparative Example 5 were soaked in hot water at 95℃±5℃ for 30 minutes, they showed signs of peeling and wrinkling.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0083] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for preparing a biodegradable, waterproof, heat-insulating, and antibacterial lunch box, characterized in that, include: Wheat straw, corn straw, reeds, cork, and starch glue are mixed to obtain a mixture. The mixture is hot-pressed, cooled, and demolded to obtain the biodegradable, waterproof, heat-insulating, and antibacterial lunch box. The raw materials for the biodegradable, waterproof, heat-insulating, and antibacterial lunch box, by weight, include: 20-30 parts wheat straw, 20-30 parts corn straw, 15-20 parts reeds, 10-20 parts cork, and 5-10 parts starch glue. The wheat straw and the corn straw are first steamed or boiled before use; The temperature of the first cooking is 100℃-120℃, the time is 0.5h-1.0h, and the pressure is 0.4Mpa-0.6Mpa; The cork is subjected to a second steaming and a first crushing process before use. The second steaming temperature is 100℃-120℃, and the time is 1.0h-1.5h; The particle size of the cork after the first crushing is 0.25cm-0.425cm; The reeds are crushed a second time before use; The beating degree of the mixture is 23°SR-26°SR. The particle size of the second crushed reed is 0.355cm-0.425cm; The hot pressing temperature is 130℃-150℃, and the time is 2min-3min.

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