Multifunctional paper pulp molded product and preparation method thereof

Abstract

The invention belongs to the technical field of intelligent packaging, and discloses a multifunctional paper pulp molded product and a preparation method thereof. The preparation method of the multifunctional paper pulp molding product comprises the following steps: preparing Chinese prickly ash anthocyanin and a bacteriostatic extracting solution, preparing a bacteriostatic fiber mixed solution and a bacteriostatic cellulose nanocrystalline solution, and preparing a paper pulp molding material for freshness monitoring from the Chinese prickly ash anthocyanin, the bacteriostatic fiber mixed solution and the bacteriostatic cellulose nanocrystalline solution. A bacteriostatic cellulose nanocrystal solution and a tannic acid solution are mixed and stirred to obtain a bacteriostatic Pickering emulsion stabilizer, a bacteriostatic extracting solution, an antibacterial aqueous phase material and the bacteriostatic Pickering emulsion stabilizer are mixed and then subjected to ultrasonic emulsification to obtain an O / W type Pickering emulsion, the O / W type Pickering emulsion is sprayed on the paper pulp molding material for freshness monitoring and then dried, and the paper pulp molding material for freshness monitoring is obtained. The molded pulp product for freshness monitoring, bacteriostasis and preservation is obtained; the problem that paper pulp molded products and food packaging materials are single in function can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of intelligent packaging, and in particular to a multifunctional pulp molded product and a preparation method thereof. Background Art

[0002] As people's living standards continue to improve, their requirements for food freshness are also increasing. Seafood is favored by people because it is rich in nutrients. However, seafood products are easily affected by microorganisms during storage, transportation and sale, causing corruption and toxicity, which is harmful to human health. Therefore, the technology of antibacterial preservation and freshness monitoring during the storage, transportation and sale of seafood products has become an important issue that needs to be solved urgently.

[0003] At present, there are some reports and studies on the antibacterial preservation, shelf life extension and freshness monitoring of seafood. For example, in "A strong carboxymethyl cellulose nanocomposite material with both antibacterial and ammonia response functions and its preparation method and application" (CN115260600A), benzoic acid is used to prepare Co-MOF nanoparticles as antibacterial detection materials, and a smart indicator shrimp and other meat foods are prepared in combination with carboxymethyl cellulose to indicate the freshness changes during storage. However, the nanoparticle preparation process is complicated and the dispersion is poor, resulting in poor monitoring and antibacterial effects. In the invention patent "A preparation method and application of an antibacterial and indicator film" (CN118146546A), bacterial cellulose and pullulan polysaccharide film are used as bactericidal and fresh-keeping materials. The substrate of the membrane, bamboo red fungus B, anthocyanin and alizarin are loaded onto the surface of the bacterial cellulose membrane and applied to photocatalytic antibacterial. The combination of bacterial cellulose and polysaccharide makes the film substrate have good mechanical properties. The photosensitizer bamboo red fungus B has a good antibacterial effect, but its preparation process is complicated and the cost is high, resulting in limited application. In "A starch / polyvinyl alcohol-based high-performance composite material with both antibacterial and pH-responsive functions and its preparation method and application" (CN115260603A), starch, polyvinyl alcohol, glycerol, rhein, and rod-shaped zinc oxide nanoparticles are used to prepare a composite material with antibacterial and pH-responsive properties for use in the field of food packaging, but rhein has certain biological toxicity and may endanger human health when used in food testing.

[0004] It can be seen that in the patents that have been published, the antibacterial and monitoring packaging materials for seafood products face many challenges, such as complex preparation processes and poor biocompatibility, which have adverse effects on the quality of seafood products and the antibacterial detection function is easily affected by the environment. It is impossible to accurately and timely monitor whether seafood products are spoiled, which makes it difficult for consumers to judge the freshness of food and increases the risk of eating spoiled seafood. Therefore, the development of a simple green packaging material with antibacterial properties that can prolong the freshness of seafood products and monitor whether food is spoiled has become the key to solving the problem. Summary of the invention

[0005] The object of the present invention is to provide a multifunctional pulp molded product and a preparation method thereof, so as to overcome the problems existing in the prior art. The present invention can use the crop Zanthoxylum bungeanum as a raw material, extract Zanthoxylum bungeanum anthocyanidin and antibacterial extracting solution through organic acid treatment and organic solvents such as ethanol, mix Zanthoxylum bungeanum fiber nanocrystals with tannic acid to prepare an antibacterial Pickering emulsion stabilizer, mix the antibacterial extracting solution, the antibacterial Pickering emulsion stabilizer and an antibacterial aqueous phase material (Chinese herbal medicine extracting solution) to prepare an antibacterial Pickering emulsion, then mix Zanthoxylum bungeanum fiber with ramie fiber and add Zanthoxylum bungeanum anthocyanidin to prepare a pulp molding material with a monitoring function, and then spray the antibacterial Pickering emulsion on the pulp molding material to obtain a pulp molding product with both seafood freshness monitoring and antibacterial preservation functions, aiming to solve the problems that pulp molding products and related food packaging materials sold on the market have a single function, lack of freshness monitoring function and poor antibacterial effect, and can make full use of Zanthoxylum bungeanum raw materials, thereby improving the high-value utilization of biomass resources.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for preparing a multifunctional pulp molded product, comprising the following steps: Step 1, preparing anthocyanins and antibacterial extracts of Zanthoxylum bungeanum; Step 2, preparing an antibacterial fiber mixed solution and an antibacterial cellulose nanocrystal solution; Step 3, preparing a pulp molding material for freshness monitoring by using anthocyanins from Zanthoxylum bungeanum, antibacterial fiber mixed solution and antibacterial cellulose nanocrystal solution; Step 4, mixing and stirring the antibacterial cellulose nanocrystal solution and the tannic acid solution to obtain an antibacterial Pickering emulsion stabilizer; Step 5, mixing the antibacterial extract, the antibacterial aqueous phase material and the antibacterial Pickering emulsion stabilizer and then performing ultrasonic emulsification to obtain an O / W type Pickering emulsion; Step 6, spraying the O / W Pickering emulsion on the pulp molding material for freshness monitoring and drying it to obtain a pulp molding product for freshness monitoring and antibacterial preservation; Furthermore, the preparation of Zanthoxylum anthocyanidins and antibacterial extracts specifically includes: Separating the dried Zanthoxylum bungeanum seeds and Zanthoxylum bungeanum peels, and grinding the dried Zanthoxylum bungeanum peels to obtain Zanthoxylum bungeanum peel powder; The peel powder of Zanthoxylum bungeanum is mixed with acidic methanol and stirred, and then filtered once to obtain a primary filtrate and a primary filter residue, respectively; the primary filter residue is mixed with acidic methanol under the same conditions and stirred, and then filtered twice to obtain a secondary filtrate and a secondary filter residue, respectively; the primary filtrate and the secondary filtrate are concentrated and evaporated to obtain a concentrated solution; the concentrated solution is freeze-dried to obtain Zanthoxylum bungeanum anthocyanidins; Adding sun-dried Zanthoxylum bungeanum seeds into an organic solvent for reaction to obtain a reaction product, filtering the reaction product to obtain a product filtrate and a product residue, respectively, allowing the product filtrate to stand for stratification to obtain an upper layer of organic matter, and performing reduced pressure distillation on the upper layer of organic matter to obtain an antibacterial extract; Furthermore, the particle size of the Zanthoxylum bungeanum peel powder is 60-120 meshes; the mass ratio of the Zanthoxylum bungeanum peel powder to the acidic methanol is 1:(20-30); the acidic methanol is obtained by mixing an organic carboxylic acid and methanol at a volume ratio of 5:1, wherein the organic carboxylic acid includes one of tartaric acid, acetic acid, and trifluoroacetic acid; the mixing temperature is 50-60°C, and the time is 1-2 h; the freeze-drying temperature is -50°C, and the time is 48 h; The mass ratio of pepper seeds to organic solvent is 1:(5-8); the organic solvent includes one or a mixed solution of methanol, ethanol, and acetone; the reaction temperature is 40-50 °C and the reaction time is 2 h; the temperature of vacuum distillation is 50 °C and the reaction time is 1 h; Furthermore, the preparation of the antibacterial fiber mixed solution and the antibacterial cellulose nanocrystal solution specifically includes: Adding bleached prickly ash fiber and bleached ramie fiber into water and mixing them to obtain an antibacterial fiber mixed liquid; The antibacterial fiber mixed solution and the hydrochloric acid solution are mixed and stirred, and then deionized water is added for centrifugal washing to obtain a suspension, and the pH value of the suspension is adjusted to neutral to obtain an antibacterial cellulose nanocrystal solution; Furthermore, the mass ratio of the bleached prickly ash fiber, the bleached ramie fiber and water is 10:(1-5):(100-150); the mass ratio of the antibacterial fiber mixture and the hydrochloric acid solution is 1:(10-20); the mass concentration of the hydrochloric acid solution is 50-70%; the temperature of the mixing and stirring is 40°C, and the time is 1-2 h; the speed of the centrifugal washing is 3000-4000 rpm, and the time is 10-20 min; Furthermore, the pulp molding material for freshness monitoring is prepared by using anthocyanins from Zanthoxylum bungeanum, antibacterial fiber mixed solution and antibacterial cellulose nanocrystal solution, specifically comprising: The anthocyanins from Zanthoxylum bungeanum, the antibacterial fiber mixed solution and the antibacterial cellulose nanocrystal solution are mixed to obtain a mixed solution, and a saturated sodium bicarbonate solution is added to the mixed solution to obtain a mixed slurry; A mixed gas of carbon dioxide and air is introduced into the mixed slurry to generate bubbles, and then a step-type pulse hot pressing process is used to dry the mixed slurry to obtain a pulp molding material for freshness monitoring; Furthermore, the mass ratio of the anthocyanidins from Zanthoxylum bungeanum, the antibacterial fiber mixed solution and the antibacterial cellulose nanocrystal solution is (0.005-0.01): 1: (0.1-0.5); the mass ratio of the antibacterial fiber mixed solution and the saturated sodium bicarbonate solution is 1: (5-8); The volume of the mixed gas introduced into each kilogram of mixed slurry is 400-800 mL; the volume ratio of carbon dioxide to air in the mixed gas is 1:5; the step-by-step pulse hot pressing process for drying includes the first stage, the second stage and the third stage, wherein the hot pressing temperature of the first stage is 40-60 °C, the hot pressing pressure is 5 MPa, and the hot pressing time is 1-2 min; the hot pressing temperature of the second stage is 65-85 °C, the hot pressing pressure is 2 MPa, and the hot pressing time is 5-10 min, and the pressure is released once every 1 min; the hot pressing temperature of the third stage is 90-110 °C, the hot pressing pressure is normal pressure, and the hot pressing time is 2-5 min; Furthermore, the mass ratio of the antibacterial cellulose nanocrystal solution to the tannic acid solution is 1:(0.1-1); the mixing and stirring treatment time is 1-2 h; The mass concentration of the antibacterial aqueous phase material is 0.1-0.3%, and the antibacterial aqueous phase material includes one of tea tree extract, rosemary extract, and honeysuckle extract; the mass ratio of the antibacterial extract, the antibacterial aqueous phase material, and the antibacterial Pickering emulsion stabilizer is 1:(2-4):(0.004-0.006); the power of ultrasonic emulsification is 200-400 W, the speed is 12000 rpm, and the time is 3-5 min; Furthermore, the spraying thickness is 5-10 μm; the drying temperature is 40° C., and the drying time is 1-2 h.

[0007] In a second aspect, the present invention further provides a multifunctional pulp molded product, which is obtained based on the above-mentioned method for preparing a multifunctional pulp molded product.

[0008] The above technical solution has the following advantages or beneficial effects: In the first aspect, the present invention provides a method for preparing a multifunctional pulp molded product, which uses common Zanthoxylum bungeanum as the main raw material, and subjecting Zanthoxylum bungeanum fruit and Zanthoxylum bungeanum wood to a series of treatments to obtain pulp molded products for food monitoring and antibacterial preservation, and uses Zanthoxylum bungeanum to monitor and protect the freshness of food, thereby realizing high-value utilization of resources; the present invention first uses Zanthoxylum bungeanum seeds to obtain an antibacterial extract, and uses Zanthoxylum bungeanum peel to prepare Zanthoxylum bungeanum anthocyanidins with monitoring functions, and then uses a foam molding process to mix Zanthoxylum bungeanum and Zanthoxylum bungeanum wood fibers with ramie fibers to prepare a pulp molding material with high bulk, and then Nanocrystals are obtained by treating the fiber mixture, and the prepared Pickering emulsion has three-phase antibacterial properties. Finally, the emulsion is sprayed on pulp molding materials. Compared with traditional food packaging materials, the antibacterial effect and safety are improved, the potential danger of food spoilage to human health is reduced, and the application range is wide. The pulp molding products make full use of the raw materials of Sichuan pepper and improve the high-value utilization of Sichuan pepper. Not only can the pulp molding products be used as buffer materials in the food transportation process, but also can be used to monitor the freshness of food. At the same time, they have excellent antibacterial and fresh-keeping effects, which extend the storage time and shelf life of food.

[0009] Furthermore, the present invention utilizes anthocyanin, an extract component of Zanthoxylum bungeanum peel, as an indicator for detecting the freshness of food. Anthocyanin-3-O-rutin and cyanidin-3-O-glucoside contained in the Zanthoxylum bungeanum peel are the most critical compounds for presenting the color of the Zanthoxylum bungeanum peel. The Zanthoxylum bungeanum peel is obtained by impregnating the Zanthoxylum bungeanum peel with an organic solvent. As the external acid-base environment changes, the structure of the Zanthoxylum bungeanum anthocyanin changes, thereby producing different color responses, achieving a colorimetric effect recognizable by the naked eye. At the same time, the Zanthoxylum bungeanum seeds are used to obtain an antibacterial extract, which mainly utilizes terpene compounds and hydrocarbon oxygen-containing organic compounds in the Zanthoxylum bungeanum seeds to achieve an antibacterial effect by destroying the cell wall of bacteria and inhibiting cell respiration metabolism, thereby causing bacterial death.

[0010] Furthermore, the present invention adopts bleached prickly ash fiber and bleached ramie fiber to prepare an antibacterial fiber mixture, wherein the prickly ash fiber itself contains alkaloid components such as prickly ash, and the ramie fiber contains trace elements such as purine, pyrimidine, etc., and has natural antibacterial properties. Ramie fiber is mixed with prickly ash fiber to achieve the extension of food storage time; by adding a certain amount of ramie fiber to the prickly ash fiber, the ramie fiber is mainly used to control the stability of bubbles introduced into the mixed gas and improve the internal bonding strength and ring pressure strength of the pulp molding material. Since the ramie fiber is long and light in weight, when the mixed gas is introduced, the bubbles generated can support the fibers, so that the fibers can be better dispersed, and the bubbles advance the distance between the fibers, increase the hydrogen bonding between the fibers, and improve the internal bonding strength and ring pressure strength of the pulp molding material. In addition, the micropores on the surface of the ramie fiber help to capture and stabilize the bubbles, provide a physical barrier for the bubbles, and reduce the merging and rupture of the bubbles.

[0011] Furthermore, the present invention uses sodium bicarbonate as an inorganic foaming material in the foam molding process, uses a mixed gas of air and carbon dioxide to obtain a large number of bubbles in an antibacterial fiber mixed liquid, and then mixes with a saturated sodium bicarbonate solution. The mixed gas is used to generate bubbles and overlap between the fibers. At the same time, due to the introduction of carbon dioxide, the saturated sodium bicarbonate solution reaches an oversaturated state, thereby recrystallizing between the fibers and the bubble liquid film to obtain sodium bicarbonate crystals of micrometers or smaller sizes. Such crystals can evenly release carbon dioxide gas in the subsequent drying process to achieve pore formation, and finally achieve a high bulk thickness of the pulp molding material; the present invention adopts a stepped pulse hot pressing process during the drying process, which can prevent the sodium bicarbonate from decomposing too quickly and causing The pores are broken, so that pulp molding materials with smaller pores and uniform size can be obtained, and the stiffness and ring crush strength of pulp molded products can be improved. The specific operation is that in the first stage, all saturated sodium bicarbonate is crystallized and precipitated, and the structural stability of the pulp molding material is maintained under high pressure. In the second stage, sodium bicarbonate is decomposed by heat to produce carbon dioxide to obtain pores, and the pressure is released once every minute to release the gas. This process can effectively avoid the problems of fiber bridging and uneven pores caused by gas accumulation. In the third stage, hot pressing is carried out at high temperature and normal pressure. The main purpose is to remove water and shape. In this stage, since high-temperature fiber collapse will not occur after the hot pressing process in the first two stages, pulp molding materials can be obtained under normal pressure.

[0012] Furthermore, the main antibacterial property of the present invention is the oil phase antibacterial extract extracted from Zanthoxylum bungeanum seeds. The antibacterial extract has good antibacterial and antioxidant properties, but is volatile and difficult to use directly. Therefore, the antibacterial aqueous phase material is prepared by using tannic acid composite cellulose nanocrystals as stabilizing particles (i.e., antibacterial Pickering emulsion stabilizer) and Chinese herbal extracts including tea tree extract, rosemary extract, honeysuckle extract, etc. in the aqueous phase.

[0013] Furthermore, an O / W Pickering emulsion is prepared by compounding an oil-phase antibacterial extract, an antibacterial aqueous phase material and an antibacterial Pickering emulsion stabilizer, wherein tannic acid contains a large number of hydroxyl groups that can combine with cellulose nanocrystals to form hydrogen bonds to enhance the stabilization effect and form a more ordered emulsion network structure. In addition, the phenolic structure of tannic acid has a certain antibacterial effect. Therefore, the aqueous phase, oil phase and particle stabilizing phase in the O / W Pickering emulsion prepared by the present invention all have antibacterial functions, and the prepared Pickering emulsion has a three-phase antibacterial property.

[0014] In the second aspect, the present invention also provides a multifunctional pulp molded product. The present invention combines the high bulk and high stiffness pulp molded product prepared by papermaking technology, has a large number of pore structures and excellent mechanical properties, and is biodegradable. Ramie fiber and prickly ash fiber are used as main materials to obtain a pulp molded product with certain antibacterial properties. Due to the pore structure of pulp molding, once food is corrupted, the gas released can better contact the prickly ash anthocyanin response detection unit, making the detection of food freshness more sensitive. In addition, other raw materials of prickly ash crops are used to prepare a Pickering emulsion with three-phase antibacterial properties. It is sprayed on one side of the pulp molding material, and due to gravity and electrostatic adsorption, the Pickering emulsion breaks, and the antibacterial components in the water phase material quickly combine with the internal fibers of the pulp molding, adsorb the antibacterial substances on the fibers, and the oil phase covers the surface of the pulp molded product through hydrogen bonds with the hydroxyl groups of the fibers, thereby obtaining a pulp molded product coating with a Janus structure. The two sides of the Janus film structure exhibit different properties. The side sprayed with the Pickering emulsion exhibits hydrophobicity due to the oil phase deposited on the surface of the pulp molding material, while the other side exhibits hydrophilicity, thereby improving the application scenarios and application value of the pulp molded products. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic flow chart of a method for preparing a multifunctional pulp molded product of the present invention; Figure 2 This is a schematic structural diagram of a multifunctional pulp molded product according to Example 1 of the present invention; Figure 3 A side view of the multifunctional pulp molded product of Example 1 of the present invention; Figure 4 It is a rear view of the multifunctional pulp molded product of Example 1 of the present invention; Figure 5 This is a schematic diagram of shrimp monitoring according to Example 1 of the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it. In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention. It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0017] Embodiment 1: See also Figure 1 The present invention provides a method for preparing a multifunctional pulp molded product, comprising the following steps: Step 1, preparing Zanthoxylum anthocyanidins and antibacterial extract: Separating the dried Zanthoxylum bungeanum seeds and Zanthoxylum bungeanum peels, and grinding the dried Zanthoxylum bungeanum peels to obtain Zanthoxylum bungeanum peel powder of 60-80 mesh; 3 g of Zanthoxylum bungeanum peel powder was put into a three-necked flask, and then 50 g of acetic acid and 10 g of methanol solution were added, stirred at 50°C for 2 h, filtered once, and a primary filtrate and a primary filter residue were obtained respectively. The primary filter residue was added into the three-necked flask again, and 50 g of acetic acid and 10 g of methanol solution were added again, stirred at 50°C for 2 h, and a secondary filtrate and a secondary filter residue were obtained respectively. The primary filtrate and the secondary filtrate were then rotary evaporated at 50°C for 1 h to obtain a concentrated solution, and the concentrated solution was freeze-dried at a cold trap coil temperature below -50°C for 48 h to obtain Zanthoxylum bungeanum anthocyanins. 5 g of sun-dried Zanthoxylum bungeanum seeds were placed in a three-necked flask, added to 25 g of methanol solution and reacted at 40 °C for 2 h to obtain a reaction product, the reaction product was filtered to obtain a product filtrate and a product residue, the product filtrate was allowed to stand for stratification to obtain an upper organic matter, and the upper organic matter was rotary evaporated at 50 °C for 1 h to obtain an antibacterial extract; Step 2: preparing an antibacterial fiber mixed solution and an antibacterial cellulose nanocrystal solution: 10 g of bleached prickly ash fiber, 1 g of bleached ramie fiber and 100 g of water were added to a three-necked flask and mixed to obtain an antibacterial fiber mixed solution. 5 g of the antibacterial fiber mixed solution was mixed with 50 g of hydrochloric acid solution at 40 °C and stirred for 2 h, and then deionized water was added to terminate the acid hydrolysis reaction. The mass concentration of the hydrochloric acid solution was 50%. The mixture was centrifuged and washed at 3000 rpm for 20 min to obtain a suspension. The pH value of the suspension was adjusted to neutral to obtain an antibacterial cellulose nanocrystal solution. Step 3: preparing a pulp molding material for freshness monitoring by using anthocyanins from Zanthoxylum bungeanum, antibacterial fiber mixed solution and antibacterial cellulose nanocrystal solution: 30 g of antibacterial fiber mixed solution was added to a beaker, and then 3 g of antibacterial cellulose nanocrystal solution and 0.15 g of anthocyanin from Zanthoxylum bungeanum were added and stirred evenly to obtain a mixed solution. 150 g of saturated sodium bicarbonate was added to the mixed solution to obtain a mixed slurry. The pulp foam forming process was used to pass 12 ml of a mixture of carbon dioxide and air into the mixed slurry through an injection mixer to generate bubbles, wherein the mixed gas contained 2 ml of carbon dioxide and 10 ml of air, and the bubble size was 50-200 μm in diameter. After stirring for 2 h, the mixture was poured into a film-forming plate and placed in a pulse dryer for drying using a step-by-step pulse hot pressing process. The step-by-step pulse hot pressing process for drying includes a first stage, a second stage and a third stage. The hot pressing temperature of the first stage was set to 40 °C, the pressure was 5 MPa, and the time was 2 min. The hot pressing temperature of the second stage was set to 65 °C, the pressure was 2 MPa, and the time was 10 min. Moreover, a pressure relief was required every 1 min to release the gas. The hot pressing temperature of the third stage was 90 °C, the pressure was 2 MPa, and the time was 10 min. ℃, the hot pressing pressure is normal pressure, the time is 5 min, and the pulp molding material with freshness monitoring function is obtained; Step 4: 1 g of the antibacterial cellulose nanocrystal solution and 0.1 g of the tannic acid solution are mixed and stirred for 1 h to obtain an antibacterial Pickering emulsion stabilizer, and the antibacterial Pickering emulsion stabilizer is stored at 4° C. for later use; Step 5, 1 g of the antibacterial extract, 2 g of the tea tree extract and 0.004 g of the antibacterial Pickering emulsion stabilizer are mixed and ultrasonically emulsified at 12000 rpm and 200 W for 5 min, wherein the mass concentration of the tea tree extract is 0.1%, to obtain an O / W Pickering emulsion; Step 6: Spray the O / W Pickering emulsion onto the pulp molded material for freshness monitoring and dry it at 40°C for 1 h. The spraying thickness is 5 μm. After the water phase disappears, the antibacterial material contained in the water phase combines with the pulp molded fiber and adsorbs on the fiber, while the oil phase remains on the surface of the pulp molded material to obtain a hydrophobic coating. Finally, a pulp molded product with a Janus structure and different hydrophobicity on both sides is obtained. See Figure 2-Figure 4 , which is a pulp molded product that has both food freshness monitoring and antibacterial and preservation functions.

[0018] The mechanical strength index of the pulp molded product obtained in Example 1 is shown in Table 1. The pulp molded product obtained in Example 1 is used to hold shrimps. Figure 5, after packaging, placed at 20 ℃ room temperature for 0 hours, it was observed that the pulp molded product was light yellow; after 48 hours, the color of the pulp molded product turned yellow, indicating that the shrimp was slightly corrupted; after 5 days, the pulp molded product turned yellow-green, and the shrimp was also seriously corrupted; the pulp molded product in Example 1 was cut and placed in a bacterial culture dish to test the antibacterial effect. It was found that the inhibition rate of the pulp molded product on Staphylococcus aureus was 96.21%, and the inhibition rate of Escherichia coli was 98.87%.

[0019] Embodiment 2: See also Figure 1 The present invention provides a method for preparing a multifunctional pulp molded product, comprising the following steps: Step 1, preparing Zanthoxylum anthocyanidins and antibacterial extract: Separating the dried Zanthoxylum bungeanum seeds and Zanthoxylum bungeanum peels, and grinding the dried Zanthoxylum bungeanum peels to obtain Zanthoxylum bungeanum peel powder of 80-100 mesh; 6 g of Zanthoxylum bungeanum peel powder was put into a three-necked flask, and then 120 g of tartaric acid and 24 g of methanol solution were added, stirred at 54 °C for 100 min, filtered once, and a primary filtrate and a primary filter residue were obtained respectively. The primary filter residue was added into the three-necked flask again, and 120 g of tartaric acid and 24 g of methanol solution were added again, stirred at 54 °C for 100 min, and a secondary filtrate and a secondary filter residue were obtained respectively. The primary filtrate and the secondary filtrate were then rotary evaporated at 50 °C for 1 h to obtain a concentrated solution, and the concentrated solution was freeze-dried at a cold trap coil temperature below -50 °C for 48 h to obtain Zanthoxylum bungeanum anthocyanins. 10 g of sun-dried Zanthoxylum bungeanum seeds were placed in a three-necked flask, added to 60 g of ethanol solution and reacted at 43 °C for 2 h to obtain a reaction product, the reaction product was filtered to obtain a product filtrate and a product residue, the product filtrate was allowed to stand for stratification to obtain an upper organic matter, and the upper organic matter was rotary evaporated at 50 °C for 1 h to obtain an antibacterial extract; Step 2: preparing an antibacterial fiber mixed solution and an antibacterial cellulose nanocrystal solution: 15 g of bleached prickly ash fiber, 3 g of bleached ramie fiber and 180 g of water were added to a three-necked flask and mixed to obtain an antibacterial fiber mixed solution. 10 g of the antibacterial fiber mixed solution was mixed with 140 g of hydrochloric acid solution at 40 °C and stirred for 100 min, and then deionized water was added to terminate the acid hydrolysis reaction. The mass concentration of the hydrochloric acid solution was 60%. The mixture was centrifuged and washed at 3400 rpm for 18 min to obtain a suspension. The pH value of the suspension was adjusted to neutral to obtain an antibacterial cellulose nanocrystal solution. Step 3: preparing a pulp molding material for freshness monitoring by using anthocyanins from Zanthoxylum bungeanum, antibacterial fiber mixed solution and antibacterial cellulose nanocrystal solution: 35 g of antibacterial fiber mixed solution was added to a beaker, and then 7 g of antibacterial cellulose nanocrystal solution and 0.21 g of anthocyanin from Zanthoxylum bungeanum were added and stirred evenly to obtain a mixed solution. 210 g of saturated sodium bicarbonate was added to the mixed solution to obtain a mixed slurry. The pulp foam molding process was used to pass 21 ml of a mixture of carbon dioxide and air into the mixed slurry through an injection mixer to generate bubbles, wherein the mixed gas contained 3.5 ml of carbon dioxide and 17.5 ml of air, and the bubble size was 50-200 μm in diameter. After stirring for 2 h, the mixture was poured into a film-forming plate and placed in a pulse dryer for drying using a step-by-step pulse hot pressing process. The step-by-step pulse hot pressing process for drying included a first stage, a second stage, and a third stage. The hot pressing temperature of the first stage was set to 44 °C, the pressure was 5 MPa, and the time was 100 s. The hot pressing temperature of the second stage was set to 75 °C, the pressure was 2 MPa, and the time was 8 min. After each 1 min, one pressure relief is required to release the gas, the hot pressing temperature of the third stage is 100 ℃, the hot pressing pressure is normal pressure, and the time is 4 min, and the pulp molding material with freshness monitoring function is obtained; Step 4, 3 g of the antibacterial cellulose nanocrystal solution and 1.2 g of the tannic acid solution were mixed and stirred for 80 minutes to obtain an antibacterial Pickering emulsion stabilizer, and the antibacterial Pickering emulsion stabilizer was stored at 4° C. for later use; Step 5, 3 g of the antibacterial extract, 7.5 g of the rosemary extract and 0.0135 g of the antibacterial Pickering emulsion stabilizer are mixed and ultrasonically emulsified at 12000 rpm and 300 W for 4 min, wherein the mass concentration of the rosemary extract is 0.2%, to obtain an O / W Pickering emulsion; Step six, spray the O / W type Pickering emulsion on the pulp molded material used for freshness monitoring and dry it at 40°C for 80 min, wherein the spraying thickness is 6 μm. After the water phase disappears, the antibacterial material contained in the water phase combines with the pulp molded fiber and adsorbs on the fiber, while the oil phase remains on the surface of the pulp molded material to obtain a hydrophobic coating, and finally obtains a pulp molded product with a Janus structure and different hydrophobicity on both sides, that is, a pulp molded product with both food freshness monitoring and antibacterial and preservation functions.

[0020] The mechanical strength index of the pulp molded product obtained in Example 2 is shown in Table 1. The pulp molded product obtained in Example 2 was used to hold shrimps, and after being packaged, it was placed at 20°C for three days before the food became corrupted, and the color of the pulp molded product changed, indicating that the pulp molded material can extend the shelf life of food and monitor the freshness of food; the pulp molded product obtained in Example 2 was used to hold shrimps, and after being packaged, it was placed at -5°C for 0 hours, and the pulp molded product was observed to be light yellow; after 7 days, the color of the pulp molded product turned yellow, indicating that the shrimps were slightly corrupted; after 10 days, the pulp molded product turned yellow-green, and the shrimps were also severely corrupted; the cut pulp molded product in Example 2 was placed in a bacterial culture dish to test the antibacterial effect, and it was found that the pulp molded product had an inhibition rate of 98.99% for Staphylococcus aureus and an inhibition rate of 99.58% for Escherichia coli.

[0021] Embodiment 3: See also Figure 1 The present invention provides a method for preparing a multifunctional pulp molded product, comprising the following steps: Step 1, preparing Zanthoxylum anthocyanidins and antibacterial extract: Separating the dried Zanthoxylum bungeanum seeds and Zanthoxylum bungeanum peels, and grinding the dried Zanthoxylum bungeanum peels to obtain Zanthoxylum bungeanum peel powder of 100-120 mesh; 9 g of Zanthoxylum bungeanum peel powder was put into a three-necked flask, and then 210 g of trifluoroacetic acid and 42 g of methanol solution were added, stirred at 58 °C for 80 min, filtered once, and a primary filtrate and a primary filter residue were obtained respectively. The primary filter residue was added into the three-necked flask again, and 210 g of trifluoroacetic acid and 42 g of methanol solution were added again, stirred at 58 °C for 80 min, and a secondary filtrate and a secondary filter residue were obtained respectively. The primary filtrate and the secondary filtrate were then rotary evaporated at 50 °C for 1 h to obtain a concentrated solution, and the concentrated solution was freeze-dried at a cold trap coil temperature below -50 °C for 48 h to obtain Zanthoxylum bungeanum anthocyanins. 15 g of sun-dried Zanthoxylum bungeanum seeds were placed in a three-necked flask, added to 105 g of acetone solution and reacted at 47 °C for 2 h to obtain a reaction product, the reaction product was filtered to obtain a product filtrate and a product residue, the product filtrate was allowed to stand for stratification to obtain an upper organic matter, and the upper organic matter was rotary evaporated at 50 °C for 1 h to obtain an antibacterial extract; Step 2: preparing an antibacterial fiber mixed solution and an antibacterial cellulose nanocrystal solution: 15 g of bleached prickly ash fiber, 6 g of bleached ramie fiber and 210 g of water were added to a three-necked flask and mixed to obtain an antibacterial fiber mixed solution. 8 g of the antibacterial fiber mixed solution was mixed with 128 g of hydrochloric acid solution at 40 °C and stirred for 80 min, and then deionized water was added to terminate the acid hydrolysis reaction. The mass concentration of the hydrochloric acid solution was 70%. The mixture was centrifuged and washed at 3800 rpm for 15 min to obtain a suspension. The pH value of the suspension was adjusted to neutral to obtain an antibacterial cellulose nanocrystal solution. Step 3: preparing a pulp molding material for freshness monitoring by using anthocyanins from Zanthoxylum bungeanum, antibacterial fiber mixed solution and antibacterial cellulose nanocrystal solution: 20 g of antibacterial fiber mixed solution was added to a beaker, and then 8 g of antibacterial cellulose nanocrystal solution and 0.16 g of anthocyanin from Zanthoxylum bungeanum were added and stirred evenly to obtain a mixed solution. 140 g of saturated sodium bicarbonate was added to the mixed solution to obtain a mixed slurry. The pulp foam forming process was used to pass 15 ml of a mixture of carbon dioxide and air into the mixed slurry through an injection mixer to generate bubbles, wherein the mixed gas contained 2.5 ml of carbon dioxide and 12.5 ml of air, and the bubble size was 50-200 μm in diameter. After stirring for 2 h, the mixture was poured into a film-forming plate and placed in a pulse dryer for drying using a step-by-step pulse hot pressing process. The step-by-step pulse hot pressing process for drying includes a first stage, a second stage and a third stage. The hot pressing temperature of the first stage was set to 50 °C, the pressure was 5 MPa, and the time was 80 s. The hot pressing temperature of the second stage was 80 °C, the pressure was 2 MPa, and the time was 6 min. Moreover, a pressure relief was required every 1 min to release the gas. The hot pressing temperature of the third stage was 105 ℃, the hot pressing pressure is normal pressure, the time is 3 min, and the pulp molding material with freshness monitoring function is obtained; Step 4: 2 g of the antibacterial cellulose nanocrystal solution and 1.6 g of the tannic acid solution are mixed and stirred for 100 minutes to obtain an antibacterial Pickering emulsion stabilizer, and the antibacterial Pickering emulsion stabilizer is stored at 4° C. for later use; Step 5, 2 g of the antibacterial extract, 7 g of the honeysuckle extract and 0.01 g of the antibacterial Pickering emulsion stabilizer are mixed and ultrasonically emulsified at 12000 rpm and 400 W for 3 min, wherein the mass concentration of the honeysuckle extract is 0.3%, to obtain an O / W Pickering emulsion; Step six, spray the O / W type Pickering emulsion on the pulp molded material used for freshness monitoring and dry it at 40°C for 100 min, wherein the spraying thickness is 8 μm. After the water phase disappears, the antibacterial material contained in the water phase combines with the pulp molded fiber and adsorbs on the fiber, while the oil phase remains on the surface of the pulp molded material to obtain a hydrophobic coating, and finally obtains a pulp molded product with a Janus structure and different hydrophobicity on both sides, that is, a pulp molded product with both food freshness monitoring and antibacterial and preservation functions.

[0022] The mechanical strength indexes of the pulp molded product obtained in Example 3 are shown in Table 1. The pulp molded product obtained in Example 3 was used to hold shrimps, and after being packaged, it was placed at a room temperature of 20°C for 3 days before the food became corrupted, and the color of the pulp molded product changed, indicating that the pulp molded material can extend the shelf life of food and monitor the freshness of food; the pulp molded product obtained in Example 3 was used to hold salmon, and after being packaged, it was placed at a room temperature of 20°C for 0 hours, and the pulp molded product was observed to be light yellow; after 48 hours, the color of the pulp molded product turned yellow, indicating that the salmon was slightly corrupted; after 5 days, the pulp molded product turned yellow-green, and the salmon was also seriously corrupted; the pulp molded product in Example 3 was cut and placed in a bacterial culture dish to test the antibacterial effect, and it was found that the inhibition rate of the pulp molded product on Staphylococcus aureus reached 97.79%, and the inhibition rate of Escherichia coli was 99.46%.

[0023] Embodiment 4: See also Figure 1 The present invention provides a method for preparing a multifunctional pulp molded product, comprising the following steps: Step 1, preparing Zanthoxylum anthocyanidins and antibacterial extract: Separating the dried Zanthoxylum bungeanum seeds and Zanthoxylum bungeanum peels, and grinding the dried Zanthoxylum bungeanum peels to obtain Zanthoxylum bungeanum peel powder of 80-100 mesh; 12 g of Zanthoxylum bungeanum peel powder was put into a three-necked flask, and then 300 g of acetic acid and 60 g of methanol solution were added, stirred at 60°C for 1 h, filtered once, and a primary filtrate and a primary filter residue were obtained respectively. The primary filter residue was added into the three-necked flask again, and 300 g of acetic acid and 60 g of methanol solution were added again, stirred at 60°C for 1 h, and a secondary filtrate and a secondary filter residue were obtained respectively. The primary filtrate and the secondary filtrate were then rotary evaporated at 50°C for 1 h to obtain a concentrated solution, and the concentrated solution was freeze-dried at a cold trap coil temperature below -50°C for 48 h to obtain Zanthoxylum bungeanum anthocyanins. 20 g of sun-dried Zanthoxylum bungeanum seeds were placed in a three-necked flask, and 80 g of ethanol and 80 g of acetone solution were added to react at 50 °C for 2 h to obtain a reaction product, and the reaction product was filtered to obtain a product filtrate and a product residue, respectively, and the product filtrate was allowed to stand for stratification to obtain an upper organic matter, and the upper organic matter was rotary evaporated at 50 °C for 1 h to obtain an antibacterial extract; Step 2: preparing an antibacterial fiber mixed solution and an antibacterial cellulose nanocrystal solution: 20 g of bleached prickly ash fiber, 10 g of bleached ramie fiber and 300 g of water were added to a three-necked flask and mixed to obtain an antibacterial fiber mixed solution. 12 g of the antibacterial fiber mixed solution was mixed with 240 g of hydrochloric acid solution at 40 °C and stirred for 1 h, and then deionized water was added to terminate the acid hydrolysis reaction. The mass concentration of the hydrochloric acid solution was 60%. The mixture was centrifuged and washed at 4000 rpm for 10 min to obtain a suspension. The pH value of the suspension was adjusted to neutral to obtain an antibacterial cellulose nanocrystal solution. Step 3: preparing a pulp molding material for freshness monitoring by using anthocyanins from Zanthoxylum bungeanum, antibacterial fiber mixed solution and antibacterial cellulose nanocrystal solution: 10 g of antibacterial fiber mixed solution was added to a beaker, and then 5 g of antibacterial cellulose nanocrystal solution and 0.1 g of anthocyanin from Zanthoxylum bungeanum were added and stirred evenly to obtain a mixed solution. 80 g of saturated sodium bicarbonate was added to the mixed solution to obtain a mixed slurry. The pulp foam forming process was used to introduce 8 ml of a mixture of carbon dioxide and air into the mixed slurry through an injection mixer to generate bubbles, wherein the mixed gas contained 1.4 ml of carbon dioxide and 7 ml of air, and the bubble size was 50-200 μm in diameter. After stirring for 2 h, the mixture was poured into a film-forming plate and placed in a pulse dryer for drying using a step-by-step pulse hot pressing process. The step-by-step pulse hot pressing process for drying includes a first stage, a second stage and a third stage. The hot pressing temperature of the first stage was set to 60 °C, the pressure was 5 MPa, and the time was 1 min. The hot pressing temperature of the second stage was set to 85 °C, the pressure was 2 MPa, and the time was 5 min. Moreover, a pressure relief was required every 1 min to release the gas. The hot pressing temperature of the third stage was 110 ℃, the hot pressing pressure is normal pressure, the time is 2 min, and the pulp molding material with freshness monitoring function is obtained; Step 4, 4 g of the antibacterial cellulose nanocrystal solution and 4 g of the tannic acid solution are mixed and stirred for 2 h to obtain an antibacterial Pickering emulsion stabilizer, and the antibacterial Pickering emulsion stabilizer is stored at 4° C. for later use; Step 5, 4 g of the antibacterial extract, 16 g of the tea tree extract and 0.024 g of the antibacterial Pickering emulsion stabilizer are mixed and ultrasonically emulsified at 12000 rpm and 300 W for 4 min, wherein the mass concentration of the tea tree extract is 0.2%, to obtain an O / W Pickering emulsion; Step six, spray the O / W type Pickering emulsion on the pulp molded material used for freshness monitoring and dry it at 40°C for 2 h, wherein the spraying thickness is 10 μm. After the water phase disappears, the antibacterial material contained in the water phase combines with the pulp molded fiber and adsorbs on the fiber, while the oil phase remains on the surface of the pulp molded material to obtain a hydrophobic coating, and finally obtains a pulp molded product with a Janus structure and different hydrophobicity on both sides, that is, a pulp molded product with both food freshness monitoring and antibacterial preservation functions.

[0024] The mechanical strength indexes of the pulp molded product obtained in Example 4 are shown in Table 1. The pulp molded product obtained in Example 4 was used to hold shrimps, and after being packaged, it was placed at 20°C for 3 days before the food became corrupted, and the color of the pulp molded product changed, indicating that the pulp molded material can extend the shelf life of food and monitor the freshness of food; the pulp molded product obtained in Example 4 was used to hold salmon, and after being packaged, it was placed at -5°C for 0 hours, and the pulp molded product was observed to be light yellow; after 7 days, the color of the pulp molded product turned yellow, indicating that the salmon was slightly corrupted; after 10 days, the pulp molded product turned yellow-green, and the salmon was also seriously corrupted; the pulp molded product in Example 4 was cut and placed in a bacterial culture dish to test the antibacterial effect, and it was found that the pulp molded product had an inhibition rate of 99.68% for Staphylococcus aureus and an inhibition rate of 99.99% for Escherichia coli.

[0025] Table 1 Performance indexes of pulp molding products

[0026] The relationship between pulp molding products and food freshness is shown in Table 2: Table 2 Relationship between pulp molding products and food freshness

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention 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 invention.

Claims

1. A method for preparing a multifunctional pulp molded product, characterized in that: The following steps are involved: preparing anthocyanins and antibacterial extracts of Zanthoxylum bungeanum; preparing an antibacterial fiber mixed solution and an antibacterial cellulose nanocrystal solution; Pulp molding materials for freshness monitoring were prepared by using Zanthoxylum anthocyanins, antibacterial fiber mixed solution and antibacterial cellulose nanocrystal solution. The antibacterial Pickering emulsion stabilizer is obtained by mixing and stirring an antibacterial cellulose nanocrystal solution and a tannic acid solution. The antibacterial extract, the antibacterial aqueous phase material and the antibacterial Pickering emulsion stabilizer are mixed and then ultrasonically emulsified to obtain an O / W type Pickering emulsion; The O / W Pickering emulsion is sprayed on a pulp molding material for freshness monitoring and then dried to obtain a pulp molding product for freshness monitoring and antibacterial preservation.

2. The method for preparing a multifunctional pulp molded product according to claim 1, characterized in that: The method for preparing anthocyanidins and antibacterial extract of Zanthoxylum bungeanum specifically comprises: Separating the dried Zanthoxylum bungeanum seeds and Zanthoxylum bungeanum peels, and grinding the dried Zanthoxylum bungeanum peels to obtain Zanthoxylum bungeanum peel powder; The peel powder of Zanthoxylum bungeanum is mixed with acidic methanol and stirred, and then filtered once to obtain a primary filtrate and a primary filter residue, respectively; the primary filter residue is mixed with acidic methanol under the same conditions and stirred, and then filtered twice to obtain a secondary filtrate and a secondary filter residue, respectively; the primary filtrate and the secondary filtrate are concentrated and evaporated to obtain a concentrated solution; the concentrated solution is freeze-dried to obtain Zanthoxylum bungeanum anthocyanidins; The dried Zanthoxylum bungeanum seeds are added into an organic solvent for reaction to obtain a reaction product, the reaction product is filtered to obtain a product filtrate and a product residue respectively, the product filtrate is allowed to stand for stratification to obtain an upper layer of organic matter, and the upper layer of organic matter is subjected to reduced pressure distillation to obtain an antibacterial extract.

3. The method for preparing a multifunctional pulp molded product according to claim 2, characterized in that: The particle size of the Zanthoxylum bungeanum peel powder is 60-120 meshes; the mass ratio of the Zanthoxylum bungeanum peel powder to the acidic methanol is 1:(20-30); the acidic methanol is obtained by mixing an organic carboxylic acid and methanol at a volume ratio of 5:1, wherein the organic carboxylic acid includes one of tartaric acid, acetic acid, and trifluoroacetic acid; the mixing temperature is 50-60°C, and the time is 1-2 h; the freeze-drying temperature is -50°C, and the time is 48 h; The mass ratio of pepper seeds to organic solvent is 1:(5~8); the organic solvent includes one or a mixed solution of methanol, ethanol, and acetone; the reaction temperature is 40~50°C and the time is 2 h; the temperature of the reduced pressure distillation is 50°C and the time is 1 h.

4. The method for preparing a multifunctional pulp molded product according to claim 1, characterized in that: The method of preparing the antibacterial fiber mixed solution and the antibacterial cellulose nanocrystal solution specifically comprises: Adding bleached prickly ash fiber and bleached ramie fiber into water and mixing them to obtain an antibacterial fiber mixed liquid; The antibacterial fiber mixed liquid and the hydrochloric acid solution are mixed and stirred, and then deionized water is added for centrifugal washing to obtain a suspension. The pH value of the suspension is adjusted to neutral to obtain an antibacterial cellulose nanocrystal solution.

5. The method for preparing a multifunctional pulp molded product according to claim 4, characterized in that: The mass ratio of the bleached prickly ash fiber, the bleached ramie fiber and water is 10:(1-5):(100-150); the mass ratio of the antibacterial fiber mixed solution and the hydrochloric acid solution is 1:(10-20); the mass concentration of the hydrochloric acid solution is 50-70%; the temperature of the mixing and stirring is 40°C, and the time is 1-2 h; the speed of the centrifugal washing is 3000-4000 rpm, and the time is 10-20 min.

6. The method for preparing a multifunctional pulp molded product according to claim 1, characterized in that: The method of preparing a pulp molding material for freshness monitoring by using anthocyanins from Zanthoxylum bungeanum, an antibacterial fiber mixed solution and an antibacterial cellulose nanocrystal solution specifically comprises: The anthocyanins from Zanthoxylum bungeanum, the antibacterial fiber mixed solution and the antibacterial cellulose nanocrystal solution are mixed to obtain a mixed solution, and a saturated sodium bicarbonate solution is added to the mixed solution to obtain a mixed slurry; A mixed gas of carbon dioxide and air is introduced into the mixed slurry to generate bubbles, and then a step-by-step pulse hot pressing process is used to dry the mixed slurry to obtain a pulp molding material for freshness monitoring.

7. The method for preparing a multifunctional pulp molded product according to claim 6, characterized in that: The mass ratio of the anthocyanidins of Zanthoxylum bungeanum, the antibacterial fiber mixed solution and the antibacterial cellulose nanocrystal solution is (0.005-0.01): 1: (0.1-0.5); the mass ratio of the antibacterial fiber mixed solution and the saturated sodium bicarbonate solution is 1: (5-8); The volume ratio of carbon dioxide to air in the mixed gas is 1:5; the step-type pulse hot pressing process for drying includes the first stage, the second stage and the third stage, wherein the hot pressing temperature of the first stage is 40~60 ℃, the hot pressing pressure is 5 MPa, and the hot pressing time is 1~2 min; the hot pressing temperature of the second stage is 65~85 ℃, the hot pressing pressure is 2 MPa, and the hot pressing time is 5~10min, and the pressure is released once every 1 min; the hot pressing temperature of the third stage is 90~110 ℃, the hot pressing pressure is normal pressure, and the hot pressing time is 2~5 min.

8. The method for preparing a multifunctional pulp molded product according to claim 1, characterized in that: The mass ratio of the antibacterial cellulose nanocrystal solution to the tannic acid solution is 1:(0.1-1); the mixing and stirring treatment time is 1-2 hours; The mass concentration of the antibacterial aqueous phase material is 0.1~0.3%, and the antibacterial aqueous phase material includes one of tea tree extract, rosemary extract, and honeysuckle extract; the mass ratio of the antibacterial extract, the antibacterial aqueous phase material, and the antibacterial Pickering emulsion stabilizer is 1:(2~4):(0.004~0.006); the power of ultrasonic emulsification is 200~400 W, the speed is 12000 rpm, and the time is 3~5 min.

9. The method for preparing a multifunctional pulp molded product according to claim 1, characterized in that: The spraying thickness is 5-10 μm; the drying temperature is 40° C. and the drying time is 1-2 h.

10. A multifunctional pulp molded product, characterized in that: The multifunctional pulp molded product is obtained based on the preparation method of claims 1-9.

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