Disposable degradable meal box and preparation method thereof

Abstract

The invention provides a disposable degradable meal box and a preparation method thereof, and relates to the field of degradable meal boxes. The disposable degradable meal box is prepared from the following raw materials in parts by weight: 30 to 40 parts of bamboo fiber, 30 to 40 parts of hulless oat straw, 20 to 30 parts of wheat straw and 20 to 30 parts of corn straw. According to the disposable degradable meal box, the wheat straw, the corn straw, the hulless oat straw and the bamboo fiber are used as raw materials, and all the raw materials can be rapidly degraded by the environment and decomposed into organic substances, so that nutrients are provided for soil, soil health and ecological system balance are promoted, environmental pollution is avoided, and comprehensive utilization of the waste straw is achieved.

Description

Technical Field

[0001] The present application relates to the field of degradable lunch boxes, and in particular to a disposable degradable lunch box and a preparation method thereof. Background Art

[0002] Straw fiber is one of the huge renewable biopolymer resources in nature. The huge waste of resources and serious environmental pollution caused by burning or burying straw are increasingly being paid attention to. At present, there have been many reports on the utilization of straw, such as fertilizer, new energy, livestock feed, degradable material, substrate for cultivating edible fungi, and building materials.

[0003] The existing technology adds a large amount of adhesives and materials that help to form. Although these materials are all green and degradable additives that can be degraded, this also significantly increases the cost of making disposable degradable straw lunch boxes. In order to better exert the performance of various materials, it is necessary to increase the complexity of the process preparation and increase the process preparation steps to achieve the preparation of degradable lunch boxes, which increases the water and electricity consumption in the preparation process, and undoubtedly increases the preparation cost of the degradable disposable lunch boxes.

[0004] In addition, some disposable degradable lunch boxes also contain additives such as adhesives and coupling agents containing polyethylene resin components. Although these can reinforce the lunch boxes and improve their oil and water resistance, the polyethylene resin microplastic particles in the adhesives and coupling agents are extremely polluting to the environment. The long-term accumulation of microplastic additives in the soil may have certain physiological toxicity to soil microorganisms, thereby inhibiting microbial activity and affecting their growth and metabolism, thereby reducing the diversity of microbial communities.

[0005] Therefore, it is an important direction to develop a disposable biodegradable lunch box that is environmentally friendly and economically adaptable without adding any additives. Summary of the invention

[0006] The purpose of the present application is to provide a disposable degradable lunch box and a preparation method thereof to solve the above-mentioned problems.

[0007] To achieve the above objectives, the first aspect of the present application provides a disposable degradable lunch box, the raw materials of which, by weight, include:

[0008] 30-40 parts of bamboo fiber, 30-40 parts of oat straw, 20-30 parts of wheat straw, and 20-30 parts of corn straw.

[0009] The second aspect of the present application provides a method for preparing the disposable degradable lunch box, comprising:

[0010] The oat straw, the wheat straw and the corn straw are mixed and treated at high temperature and high pressure to obtain a first material;

[0011] The first material is subjected to fiber dissociation to obtain a second material;

[0012] The second material and the bamboo fiber are molded by a wet process to obtain a target wet embryo;

[0013] The wet embryo is subjected to hot pressing to obtain the disposable degradable lunch box.

[0014] Optionally, the bamboo fiber is pretreated before use.

[0015] Optionally, the pretreatment temperature is 160° C.-260° C., the pretreatment pressure is 0.69 MPa-4.83 MPa, and the pretreatment time is 1 h-4 h.

[0016] Optionally, the temperature of the high temperature and high pressure treatment is 110°C-130°C, the pressure is 0.142Mpa-0.35Mpa, and the time is 2h-5h.

[0017] Optionally, the fiber dissociation includes a first fiber dissociation and a second fiber dissociation performed sequentially;

[0018] The number of dissociation turns of the first fiber dissociation is 1800 turns to 2200 turns;

[0019] The number of dissociation turns for dissociating the second fiber is 1600-2000 turns.

[0020] Optionally, the beating degree of the second material is 23°SR-25°SR.

[0021] Optionally, the molding wet forming comprises:

[0022] The second material and water are mixed and stirred to obtain a slurry;

[0023] The slurry is first dehydrated to form wet embryos to be processed, and residual slurry remains in the accommodating space of the wet embryos to be processed;

[0024] The bamboo fiber is added to the surface of the residual slurry, and then a second dehydration and demoulding are performed to obtain the target wet embryo.

[0025] Optionally, the method for preparing the disposable degradable lunch box satisfies at least one of the following conditions:

[0026] A. the second dehydration comprises vacuum dehydration;

[0027] B. The second dehydration is performed 3 to 4 times.

[0028] Optionally, the temperature of the hot pressing molding is 140° C.-160° C., and the time is 130s-140s.

[0029] Compared with the prior art, the beneficial effects of this application include:

[0030] The present application provides a disposable degradable lunch box, which uses wheat straw, corn straw, oat straw and bamboo fiber as raw materials, wherein oat straw and bamboo fiber complement the common fibers of corn straw and wheat straw, and wheat straw is rich in cellulose and lignin, which helps to increase the compression and tensile resistance of the disposable degradable lunch box; corn straw has excellent degradability and mechanical properties, and can provide a solid structure and durability for the disposable degradable lunch box; oat straw has good water resistance and heat resistance, and can improve the durability and service life of the disposable degradable lunch box; bamboo has high antibacterial and antioxidant properties, and can effectively extend the shelf life of the disposable degradable lunch box; the above raw materials can all be rapidly degraded by the environment, decomposed into organic matter, provide nutrients to the soil, promote soil health and ecosystem balance, will not cause environmental pollution, and realize the comprehensive utilization of waste straw.

[0031] The present application provides a method for preparing a disposable degradable lunch box, which breaks a part of the chemical bonds in the lignin molecules in the oat straw, wheat straw and corn straw through high temperature and high pressure treatment, so that the lignin molecules are decomposed to generate compounds with higher viscosity, thereby increasing the adhesion inside the oat straw, wheat straw and corn straw, and can replace traditional adhesives and materials that help to form. Then, bamboo fiber is covered on the surface. The bamboo fiber surface has a layer of natural waxy substance that can prevent water and grease from penetrating into the fiber. By covering the surface of the lunch box, it becomes a natural oil-proof and waterproof layer. The disposable degradable lunch box finally prepared uses natural raw materials without adding any additives, thereby achieving the purpose of environmental protection, green and pollution-free. The preparation method is simple and efficient, and the raw materials are easily available. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0033] Figure 1 This is the measurement diagram of the water drop contact angle of the bamboo fiber after heating;

[0034] Figure 2 This is a SEM image of the disposable oil-proof and waterproof degradable lunch box prepared in Example 1;

[0035] Figure 3This is a physical picture of the disposable oil-proof, waterproof and degradable lunch box prepared in Example 1. DETAILED DESCRIPTION

[0036] As used herein:

[0037] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0038] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0039] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0040] In these examples, parts and percentages are by mass unless otherwise indicated.

[0041] "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass of all components is not limited to 100 parts.

[0042] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0043] The first aspect of the present application provides a disposable degradable lunch box, the raw materials of which, by weight, include:

[0044] 30-40 parts of bamboo fiber, 30-40 parts of oat straw, 20-30 parts of wheat straw, and 20-30 parts of corn straw.

[0045] It should be noted that bamboo fiber has the effects of clearing away heat and detoxifying, clearing away heat and relieving restlessness, and promoting fluid production and diuresis. By adding bamboo leaves to disposable degradable lunch boxes, some of the bamboo leaf ingredients can be ingested while eating, thus achieving the above-mentioned effects; wheat straw and corn straw are relatively hard, have certain strength and toughness, and the disposable degradable lunch boxes made from them have certain durability; oat straw fiber is filament-like, has a continuous fiber structure, and has high strength. It is tougher than other types of crop straw such as ordinary soybean straw, wheat straw and corn straw, has good strength and toughness, and is easy to mix with other fibers, which greatly utilizes the characteristics of oat straw fiber. After consumption, it can also help lower blood lipids and blood sugar, enhance immunity, and lower cholesterol in the human body.

[0046] Optionally, the raw materials are measured by weight: bamboo fiber can be 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts or any value between 30 parts and 40 parts; oat straw can be 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts, 40 parts or any value between 30 parts and 40 parts. the wheat straw can be 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 parts and 30 parts, and the corn straw can be 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 parts and 30 parts.

[0047] The second aspect of the present application provides a method for preparing the disposable degradable lunch box, comprising:

[0048] The oat straw, the wheat straw and the corn straw are mixed and treated at high temperature and high pressure to obtain a first material;

[0049] The first material is subjected to fiber dissociation to obtain a second material;

[0050] The second material and the bamboo fiber are molded by a wet process to obtain a target wet embryo;

[0051] The wet embryo is subjected to hot pressing to obtain the disposable degradable lunch box.

[0052] In some embodiments, the bamboo fiber is pretreated before use.

[0053] In some embodiments, the pretreatment temperature is 160° C.-260° C., the pretreatment pressure is 0.69 MPa-4.83 MPa, and the pretreatment time is 1 h-4 h.

[0054] Optionally, the pretreatment temperature can be 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃ or any value between 160℃-260℃, the pretreatment pressure can be 0.69MPa, 1MPa, 2MPa, 3MPa, 4MPa, 4.83MPa or any value between 0.69MPa-4.83MPa, and the time can be 1h, 2h, 3h, 4h or any value between 1h-4h.

[0055] It should be noted that pretreatment can change the physical and chemical properties of bamboo fiber, improve its density and water resistance, and enhance its waterproof and oil-proof properties. After the pretreatment, the bamboo fiber is cooled to room temperature to solidify the surface structure, which can increase the density and stability of the bamboo fiber and improve its water resistance and oil-proof properties. Figure 1 As shown in the figure, it is a test picture of bamboo fiber placed on the workbench of the contact angle measuring instrument after heat treatment. The water droplet is just dropped on the surface of bamboo fiber ( Figure 1 left image) to completely disappearing ( Figure 1 The average time for the test was 36.7 minutes.

[0056] It should be noted that according to the properties of bamboo fiber and the desired improvement effect, an appropriate heat treatment temperature should be set to ensure that the bamboo fiber is heated evenly and to avoid overheating or too short a treatment time.

[0057] In some embodiments, the temperature of the high temperature and high pressure treatment is 110° C.-130° C., the pressure is 0.142 MPa-0.35 MPa, and the time is 2 h-5 h.

[0058] Optionally, the temperature of the high temperature and high pressure treatment can be 110℃, 115℃, 120℃, 125℃, 130℃ or any value between 110℃-130℃, the pressure can be 0.142Mpa, 0.15Mpa, 0.2Mpa, 0.25Mpa, 0.3Mpa, 0.35Mpa or any value between 0.142Mpa-0.35Mpa, and the time can be 2h, 3h, 4h, 5h or any value between 2h-5h.

[0059] In some embodiments, the fiber dissociation includes a first fiber dissociation and a second fiber dissociation performed sequentially;

[0060] The number of dissociation turns of the first fiber dissociation is 1800 turns to 2200 turns;

[0061] Optionally, the number of dissociation turns for the first fiber dissociation may be 1800 turns, 1900 turns, 2000 turns, 2100 turns, 2200 turns or any value between 1800 turns and 2200 turns;

[0062] The number of dissociation turns for dissociating the second fiber is 1600-2000 turns.

[0063] Optionally, the number of dissociation turns for the second fiber dissociation may be 1600 turns, 1700 turns, 1800 turns, 1900 turns, 2000 turns or any value between 1600 turns and 2000 turns.

[0064] It should be noted that fiber dissociation includes first fiber dissociation and second fiber dissociation performed sequentially. The first fiber dissociation is to grind the crop straw preliminarily, and the second fiber dissociation can dissociate the fibers more evenly and fully. Sufficiently even and sufficient fiber dissociation plays a vital role in wet embryo forming.

[0065] In some embodiments, the second material has a beating degree of 23°SR-25°SR.

[0066] Optionally, the beating degree of the second material may be 23°SR, 24°SR, 25°SR or any value between 23°SR and 25°SR.

[0067] It should be noted that the beating degree of the second material is 23°SR-25°SR. This is because the lunch box needs to have a certain mechanical strength to withstand the weight of food and external pressure. Too high a beating degree will lead to insufficient bonding between fibers, affecting the strength and durability of the finished product. A moderate beating degree helps the fluidity of the pulp during the molding process. Too high a beating degree will make the pulp sticky, affecting the molding effect and uniformity, while too low a beating degree may result in a loose structure of the finished product. Paper lunch boxes need to have a certain degree of waterproofness and air permeability during use. When the beating degree is 23°SR-25°SR, it can enhance the adhesion of the waterproof treatment agent while maintaining appropriate air permeability. During the production process, the adjustment of the beating degree also affects the adaptability of subsequent processes (such as drying, coating, etc.). Controlling the beating degree within the range of 23°SR-25°SR can ensure the stability of the production line operation. By controlling the beating degree, the utilization efficiency of raw materials can also be optimized, material waste can be reduced, and production costs can be reduced.

[0068] In some embodiments, the molding wet forming comprises:

[0069] The second material and water are mixed and stirred to obtain a slurry;

[0070] Preferably, the stirring includes pneumatic stirring, so that the second material can be completely dispersed in the water and the slurry is in a turbid state.

[0071] It should be noted that pneumatic stirring can provide a uniform mixing effect without affecting the material, especially when dealing with viscous or highly viscous liquids, pneumatic stirring can more effectively break the surface tension of the liquid and make the composition more uniform; pneumatic stirring inserts gas during the mixing process, thereby reducing bubbles generated by mechanical stirring; pneumatic stirring, due to the use of gas power, can usually reduce the required stirring torque, which can reduce the burden on the stirring equipment, extend the service life of the equipment, and reduce energy consumption; pneumatic stirring systems are generally more adaptable and can handle a variety of different materials and fluids, including high viscosity and granular substances; since there are no mechanical parts directly in contact with the liquid, pneumatic stirring tends to have less wear during long-term use, thereby improving the reliability and service life of the equipment.

[0072] The slurry is first dehydrated to form wet embryos to be processed, and residual slurry remains in the accommodating space of the wet embryos to be processed;

[0073] The bamboo fiber is added to the surface of the residual slurry, and then a second dehydration and demoulding are performed to obtain the target wet embryo.

[0074] It should be noted that demoulding includes machine air blowing demoulding and / or vacuum demoulding.

[0075] In some embodiments, the equipment used for molding wet forming can be an intermittent fiber wet forming equipment that can automatically add water.

[0076] It should be noted that the wet molding process includes: placing the second material and water in a wet molding-related device, stirring the second material to completely break up the second material in the water, and then quickly dehydrating the second material to form a uniform lunch box-shaped wet embryo on the bottom surface of the mold. However, there is residual slurry in the lunch box-shaped wet embryo accommodating space. Preferably, the lunch box-shaped wet embryo accommodating space is filled with slurry, and then bamboo fiber is added to allow the bamboo fiber to be evenly dispersed on the slurry, and then vacuum dehydration is performed so that the upper surface of the lunch box-shaped wet embryo is evenly covered with bamboo fiber.

[0077] In some embodiments, the method for preparing the disposable degradable lunch box satisfies at least one of the following conditions:

[0078] A. the second dehydration comprises vacuum dehydration;

[0079] B. The second dehydration is performed 3 to 4 times.

[0080] In some embodiments, the temperature of the hot pressing molding is 140° C.-160° C., and the time is 130s-140s.

[0081] Optionally, the temperature of the hot pressing molding may be 140°C, 145°C, 150°C, 155°C, 160°C or a range value between 140°C and 160°C, and the time may be 130s, 135s, 140s or a range value between 130s and 140s.

[0082] It should be noted that the hot pressing temperature of 140℃-160℃ and the time of 130s-140s can change the physical and chemical properties of bamboo fiber, increase its density and water resistance, and enhance its waterproof and oil-proof properties.

[0083] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0084] Example 1

[0085] The first aspect of the present embodiment provides a disposable oil-proof and waterproof degradable lunch box, and the raw materials thereof, measured by weight, include:

[0086] 15 grams of bamboo fiber, 15 grams of oat straw, 10 grams of wheat straw, and 10 grams of corn straw.

[0087] A second aspect of the present embodiment provides a method for preparing a disposable oil-proof, waterproof and degradable lunch box, comprising:

[0088] S1: Soak the wheat straw, corn straw and oat straw for 6 hours until the straw is completely soaked and changes from light yellow to dark brown;

[0089] S2: Put the processed straw into a pressure cooker and steam it at a preset pressure of 0.3 Mpa to obtain the first material at a temperature of 125° C. for 3 hours;

[0090] The bamboo fiber was pretreated at a temperature of 200°C, a pressure of 1.55 MPa, and a time of 3 h;

[0091] S3: placing the first material into a fiber dissociation disperser, and sequentially performing first fiber dissociation and second fiber dissociation, the number of turns of the first fiber dissociation is 1800, after which the straw fibers are shaken apart, and then performing second fiber dissociation, the number of turns is 1600, to obtain a second material;

[0092] S4: Take 30g / 1000mL of the second material and put it into a measuring cylinder, shake it thoroughly, and then pour it into a beating degree measuring instrument. The instrument shows 25°SR;

[0093] S5: putting the second material into an intermittent fiber wet forming device, the device can automatically add tap water, and then pneumatic stirring is performed for 140 seconds to completely break up the second material in the water, and the slurry is in a turbid state. The slurry is first dehydrated to form a wet embryo to be processed, and residual slurry is retained in the accommodating space of the wet embryo to be processed, and the pretreated bamboo fiber is added, and the bamboo fiber is evenly located on the upper part of the slurry, and then vacuum dehydration is performed for 140 seconds, and dehydration is performed 3 times. The whole demoulding is achieved by alternating the machine air blowing demoulding and vacuum demoulding functions to obtain the target wet embryo;

[0094] S6: The target wet embryo is placed into a mold of a pulp molding hot pressing shaping device, the hot pressing temperature is 144°C, and the hot pressing time is 135s to obtain a disposable oil-proof, waterproof and degradable lunch box.

[0095] The SEM image of the disposable oil-proof and waterproof biodegradable lunch box is as follows Figure 2 shown.

[0096] The disposable oil-proof and waterproof degradable lunch box is as follows Figure 3 shown.

[0097] Example 2

[0098] The first aspect of the present embodiment provides a disposable oil-proof and waterproof degradable lunch box, and the raw materials thereof, measured by weight, include:

[0099] 15 grams of bamboo fiber, 15 grams of oat straw, 10 grams of wheat straw, and 10 grams of corn straw.

[0100] A second aspect of the present embodiment provides a method for preparing a disposable oil-proof, waterproof and degradable lunch box, comprising:

[0101] S1: Soak the wheat straw, corn straw and oat straw for 6 hours until the straw is completely soaked and changes from light yellow to dark brown;

[0102] S2: Put the processed straw into a pressure cooker and steam it at a preset pressure of 0.3 Mpa to obtain the first material at a temperature of 125° C. for 3 hours;

[0103] S3: placing the first material into a fiber dissociation disperser, and sequentially performing first fiber dissociation and second fiber dissociation, the number of turns of the first fiber dissociation is 1800, after which the straw fibers are shaken apart, and then performing second fiber dissociation, the number of turns is 1600, to obtain a second material;

[0104] S4: Take 30g / 1000mL of the second material and put it into a measuring cylinder, shake it thoroughly, and then pour it into a beating degree measuring instrument. The instrument shows 25°SR;

[0105] S5: putting the second material into an intermittent fiber wet forming device, the device can automatically add tap water, and then pneumatic stirring is performed for 140 seconds to completely break up the second material in the water, and the slurry is in a turbid state. The slurry is first dehydrated to form a wet embryo to be processed, and residual slurry is retained in the accommodating space of the wet embryo to be processed, and bamboo fiber is added. The bamboo fiber is evenly located on the upper part of the slurry, and then vacuum dehydration is performed for 140 seconds, and dehydration is performed 3 times. The whole demoulding is achieved by alternating the machine air blowing demoulding and vacuum demoulding functions to obtain the target wet embryo;

[0106] S6: The target wet embryo is placed into a mold of a pulp molding hot pressing shaping device, the hot pressing temperature is 144°C, and the hot pressing time is 135s to obtain a disposable oil-proof, waterproof and degradable lunch box.

[0107] Example 3

[0108] The first aspect of the present embodiment provides a disposable oil-proof and waterproof degradable lunch box, and the raw materials thereof, measured by weight, include:

[0109] 15g bamboo fiber, 15g oat straw, 10g wheat straw, 10g corn straw;

[0110] The bamboo fiber was pretreated at a temperature of 200°C, a pressure of 1.55 MPa, and a time of 3 h;

[0111] A second aspect of the present embodiment provides a method for preparing a disposable oil-proof, waterproof and degradable lunch box, comprising:

[0112] S1: putting wheat straw, corn straw and oat straw into a pressure cooker, and steaming them at a preset pressure of 0.3 Mpa to obtain a first material at a temperature of 125° C. for 3 h;

[0113] S2: placing the first material into a fiber dissociation disperser, and sequentially performing first fiber dissociation and second fiber dissociation, the number of turns of the first fiber dissociation is 1800, after which the straw fibers are shaken apart, and then performing second fiber dissociation, the number of turns is 1600, to obtain the second material;

[0114] S3: Take 30g / 1000mL of the second material and put it into a measuring cylinder, shake it thoroughly, and then pour it into a beating degree measuring instrument. The instrument shows 25°SR;

[0115] S4: putting the second material into an intermittent fiber wet forming device, the device can automatically add tap water, and then pneumatic stirring is performed for 140 seconds to completely break up the second material in the water, and the slurry is in a turbid state. The slurry is first dehydrated to form a wet embryo to be processed, and residual slurry is retained in the accommodating space of the wet embryo to be processed, and the pretreated bamboo fiber is added, and the bamboo fiber is evenly located on the upper part of the slurry, and then vacuum dehydration is performed for 140 seconds, and dehydration is performed 3 times. The overall demoulding is achieved by alternating the machine air blowing demoulding and vacuum demoulding functions to obtain the target wet embryo;

[0116] S5: The target wet embryo is placed into a mold of a pulp molding hot pressing shaping device at a hot pressing temperature of 144° C. for 135 seconds to obtain a disposable oil-proof, waterproof and degradable lunch box.

[0117] Comparative Example 1

[0118] This comparative example provides a disposable degradable lunch box and a preparation method thereof, which is different from Example 1 in that the raw materials of this comparative example do not contain bamboo fiber, and other conditions are consistent with Example 1.

[0119] Comparative Example 2

[0120] This comparative example provides a disposable degradable lunch box and a preparation method thereof, which is different from Example 1 in that the raw materials of this comparative example do not contain oat straw, and other conditions are consistent with Example 1.

[0121] Comparative Example 3

[0122] This comparative example provides a disposable degradable lunch box and a preparation method thereof, which is different from Example 1 in that the raw materials of this comparative example do not contain wheat straw, and other conditions are consistent with Example 1.

[0123] Comparative Example 4

[0124] This comparative example provides a disposable degradable lunch box and a preparation method thereof, which is different from Example 1 in that the raw materials of this comparative example do not contain corn stalks, and other conditions are consistent with Example 1.

[0125] Comparative Example 5

[0126] This comparative example provides a disposable oil-proof and waterproof degradable lunch box and a preparation method thereof. The difference from Example 1 is that bamboo fiber is added during the high temperature and high pressure treatment step in this comparative example. The specific steps are as follows:

[0127] S1: Soak the wheat straw, corn straw and oat straw for 6-8 hours until the straw is completely soaked and changes from light yellow to dark brown;

[0128] S2: Put the processed straw and bamboo fiber into a pressure cooker and steam them at a preset pressure of 0.3 Mpa to obtain the first material at a temperature of 125° C. for 3 hours;

[0129] S3: placing the first material into a fiber dissociation disperser, and sequentially performing first fiber dissociation and second fiber dissociation, the number of turns of the first fiber dissociation is 1800, after which the straw fibers are shaken apart, and then performing second fiber dissociation, the number of turns is 1600, to obtain a second material;

[0130] S4: Take 30g / 1000mL of the second material and put it into a measuring cylinder, shake it thoroughly, and then pour it into a beating degree measuring instrument. The instrument shows 25°SR;

[0131] S5: The second material is placed in an intermittent fiber wet forming device, and tap water can be automatically added to the device, followed by pneumatic stirring for 140 seconds to completely disperse the second material in the water, and the slurry is in a turbid state. The slurry is first dehydrated to form a wet embryo to be processed, and then vacuum dehydration is performed for 140 seconds, and dehydration is performed 3 times. The whole demoulding is achieved by alternating the machine's air blowing demoulding and vacuum demoulding functions to obtain the target wet embryo;

[0132] S6: The target wet embryo is placed into a mold of a pulp molding hot pressing shaping device at a hot pressing temperature of 144° C. and a hot pressing time of 135 s to obtain a disposable biodegradable lunch box.

[0133] The lunch boxes prepared in the above Examples 1-3 and Comparative Examples 1-5 were subjected to oil-proof, waterproof and degradable tests. According to the standards GB 4806.7-2016 and GB 9685-2016 issued for disposable paper lunch boxes, the standards for disposable paper lunch boxes can be known: temperature resistance test (oil and water at 95°C ± 5°C, 30min), the test conditions for weight loss rate are: the change in weight of the disposable lunch box in the soil over time, the test time is the weight change from the 7th day to the 21st day, and the specific test results are shown in Table 1.

[0134] Table 1 Oil resistance, water absorption and degradability test

[0135]

[0136] The oil and water resistance of Example 1 is the most outstanding. The relevant oil and water resistance test is: the weight of the oil and water dropped in the lunch box is a fixed value. The oil absorption rate result in Table 1 is the weight percentage of the oil volume reduced compared to the initial value at the 30th minute; the water absorption rate result is the weight percentage of the water volume reduced compared to the initial value at the 30th minute. The degradability of Example 1 is more outstanding. The relevant degradable test is the change of the weight of the disposable lunch box in the soil environment over time. The test results show that the weight increased from a decrease of 10.7% on the 7th day to a decrease of 25.9% on the 21st day. This is due to the interaction between the environment and microorganisms that leads to the loss of bound water in the sample. Microorganisms will decompose cellulose and other hygroscopic components. The lunch box containing bamboo fiber is slower to degrade because the bamboo fiber has a tight structure and a relatively slow decay rate.

[0137] The oil and water repellency of Example 2 is poorer than that of Example 1, Example 3 and Comparative Examples 2 to 5. The main reason is that the bamboo fiber has not been fully pretreated at a specific temperature and pressure, which will lead to poor oil and water repellency. It is known from the analysis of experimental data that the natural structure of the bamboo fiber contains many tiny pores, which easily absorb water and grease, resulting in reduced waterproof and oil repellency. If the tiny pores are pretreated, they may be partially filled, thereby reducing their ability to absorb water and oil. Some natural water-soluble components and grease are removed during the pretreatment process, which may make the fiber surface smoother, which will help reduce the adhesion and penetration of liquids on the surface. Improve the hydrophobicity of bamboo fiber, thereby improving its waterproof and oil repellency.

[0138] In comparative example 1, the raw material does not include bamboo fiber. Because there is no bamboo fiber, the degradation rate will become faster, but it is difficult to achieve oil and water resistance. The microstructure of bamboo fiber has a high porosity, which enables it to effectively resist the penetration of water. This is how the necessity of bamboo fiber for this disposable degradable lunch box is more prominent. In comparative example 2, the raw material does not include oat straw. Because oat straw has a high cellulose content, it is usually easier to be decomposed by microorganisms and has strong degradability. Therefore, without adding oat straw, its degradation rate will slow down, and there is not much difference in oil and water resistance. In comparative example 3, the raw material does not include wheat straw. The degradability of wheat straw is better, but compared with oat straw, the degradation rate is slightly slower, and there is not much difference in oil and water resistance. In comparative example 4, the raw material does not include corn straw. The degradability of corn straw is not as good as oat straw and wheat straw, so the degradation rate is slow.

[0139] In Comparative Example 5, bamboo fiber is added during the high temperature and high pressure treatment step, and the bamboo fiber is added to other types of straw pulp to form a wet embryo together. The difference between it and other comparative examples is that the bamboo fiber is not evenly covered on the surface of the disposable degradable lunch box. There are gaps between the bamboo fiber added to the pulp and the oat straw, wheat straw, and corn straw. Oil and water will be absorbed by the straw in the gaps, so it is difficult to ensure that it can be as uniform as a coating, and its oil and water resistance will be significantly affected.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0141] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A disposable degradable lunch box, characterized in that: The raw materials include, by weight: 30-40 parts of bamboo fiber, 30-40 parts of oat straw, 20-30 parts of wheat straw, and 20-30 parts of corn straw.

2. A method for preparing the disposable degradable lunch box according to claim 1, characterized in that: include: The oat straw, the wheat straw and the corn straw are mixed and treated at high temperature and high pressure to obtain a first material; The first material is subjected to fiber dissociation to obtain a second material; The second material and the bamboo fiber are molded by a wet process to obtain a target wet embryo; The wet embryo is subjected to hot pressing to obtain the disposable degradable lunch box.

3. The method for preparing a disposable degradable lunch box according to claim 2, characterized in that: The bamboo fiber is pretreated before use.

4. The method for preparing a disposable degradable lunch box according to claim 3, characterized in that: The pretreatment temperature is 160° C.-260° C., the pretreatment pressure is 0.69 MPa-4.83 MPa, and the pretreatment time is 1 h-4 h.

5. The method for preparing a disposable degradable lunch box according to claim 2, characterized in that: The temperature of the high temperature and high pressure treatment is 110° C.-130° C., the pressure is 0.142 MPa-0.35 MPa, and the time is 2 h-5 h.

6. The method for preparing a disposable degradable lunch box according to claim 2, characterized in that: The fiber dissociation includes a first fiber dissociation and a second fiber dissociation performed sequentially; The number of dissociation turns of the first fiber dissociation is 1800 turns to 2200 turns; The number of dissociation turns for dissociating the second fiber is 1600-2000 turns.

7. The method for preparing a disposable degradable lunch box according to claim 2, characterized in that: The beating degree of the second material is 23°SR-25°SR.

8. The method for preparing a disposable degradable lunch box according to claim 2, characterized in that: The wet molding process comprises: The second material and water are mixed and stirred to obtain a slurry; The slurry is first dehydrated to form wet embryos to be processed, and residual slurry remains in the accommodating space of the wet embryos to be processed; The bamboo fiber is added to the surface of the residual slurry, and then a second dehydration and demoulding are performed to obtain the target wet embryo.

9. The method for preparing a disposable degradable lunch box according to claim 8, characterized in that: At least one of the following conditions is met: A. the second dehydration comprises vacuum dehydration; B. The second dehydration is performed 3 to 4 times.

10. The method for preparing a disposable degradable lunch box according to any one of claims 2 to 9, characterized in that: The temperature of the hot pressing molding is 140° C.-160° C., and the time is 130s-140s.

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