Fruit and vegetable cold chain logistics micro-environment control box

Abstract

The present invention relates to a fruit and vegetable cold chain logistics microenvironment control box, including a nano-TiO2 modified polyurethane insulation layer storage cavity, a solar micro semiconductor refrigerator is installed on one side of the storage cavity, and its refrigeration power comes from a solar photovoltaic panel that stores electricity from a solar cell, the solar photovoltaic panel is located on an upper cover, and an inverter and a battery are arranged on both sides of the solar photovoltaic panel, and the battery is connected to a DC micro vacuum pump. The present invention utilizes a solar micro semiconductor refrigerator, a static pressure ventilation panel and a DC micro vacuum pump in combination with a nano-TiO2 modified polyurethane insulation layer material to achieve timely precooling of fruits and vegetables after harvesting, effectively inhibit bacteria, complete 1-MCP treatment in the first time, and can achieve precise temperature control of a long-term logistics distribution process, while automatically completing spontaneous gas conditioning treatment, reducing O2 in the box, and effectively removing harmful metabolites such as ethylene and acetaldehyde, reducing the respiratory rate, slowing down the consumption of organic matter, and improving the logistics and storage quality of fruits and vegetables.

Description

Technical Field

[0001] The invention belongs to the field of post-harvest storage and preservation of fruits and vegetables, relates to cold chain logistics preservation technology, and in particular to a fruit and vegetable cold chain logistics microenvironment control box. Background Art

[0002] my country is a major producer of fruits and vegetables, with a total output of 970 million tons of fruits and vegetables. Fresh fruits and vegetables have high moisture and sugar content, and are very prone to decay, mechanical damage and disease after harvest, resulting in quality deterioration. In addition, there are many types and varieties of fruit and vegetable products, and most of them are harvested seasonally and put on the market in batches, resulting in a 20%-30% loss of fruits and vegetables after harvest, with economic losses exceeding 200 billion yuan. Especially for high-value perishable fruits and vegetables, due to the inability to pre-cool them in time after picking, their quality in the logistics process deteriorates rapidly, decay increases, commodity quality is poor, and the shelf life is short, and the damage is more serious. 1-Methylcyclopropene (1-MCP) is a new type of ethylene receptor inhibitor that can significantly extend the shelf life of fruits and vegetables. At present, fruits and vegetables in my country are first harvested, stacked in a specific location in the field, and then uniformly transported to the purchase and processing point, and then 1-MCP is processed, missing the best use time of 1-MCP (processing is completed within 24 hours after harvesting), which makes it difficult for 1-MCP to play a role. In addition, due to the lack of technical means such as gas regulation and anti-corrosion control during the logistics and distribution process, the rot rate of fruits and vegetables in e-commerce remains high.

[0003] Most of the existing cold chain logistics boxes in my country use polyurethane or polystyrene box insulation with built-in ice packs. There are problems such as poor thermal insulation performance of the insulation material, poor mechanical properties, easy aging, uneven temperature inside the box, short low-temperature retention time, and poor cold storage performance. Most of them can only maintain low temperatures for 48-72 hours and cannot meet long-term low-temperature logistics needs.

[0004] Through the search of existing public patent documents, there are several technical related public patent documents:

[0005] 1. Fruit and vegetable fresh-keeping box and preservation method, CN103693300B, is a cylindrical box with a circular opening on the top surface and the opening covered with an insulating cover. The insulating cover and the box body are insulating panels with iron sheets inside and outside and a foam insulation layer in the middle. There are ventilation holes in the middle of the insulating cover and the bottom of the box, and a water outlet is also opened at the bottom of the box. A funnel-shaped hole net is provided at the bottom of the box, and a conical double-layer grid is provided in the middle of the box. The upper opening of the conical double-layer grid is equal to the size of the insulating cover, and ice cubes are placed in the middle.

[0006] Although the above-mentioned patented technology can be used for heat preservation and ventilation, ventilation causes large temperature fluctuations in the box, making it difficult to achieve low-temperature delivery; and the insulation material uses a foam insulation layer, which has a large thermal conductivity and poor insulation effect.

[0007] 2. A fruit and vegetable fresh-keeping box, CN106956867A, is based on corrugated cardboard and comprises a box body, a handle is arranged on the top of the box body, a window is arranged on one side of the box body, the interior of the box body is hollow to form a chamber, and the chamber is divided into multiple spaces by a partition, the partition has a groove, a layer of cardboard with a wavy cross-section is adhered to the lower surface of the partition, and a solid fruit and vegetable preservative is placed in the gap of the cardboard.

[0008] The patented technology prepares a porous chitosan-based composite preservative, including alkali sulfide, bentonite, diatomaceous earth, micron-sized carbon balls, fillers, etc. However, the release effect of the preservative is uneven, and there is no circulation device in the box. There are technical problems such as the box body of the fresh-keeping box is not heat-insulating, not resistant to moisture, and cannot be circulated in the cold chain.

[0009] 3. A logistics turnover box based on food preservation and transportation, CN106275837A, consists of a double-sided pallet, a box body plate movably installed above the chassis, and sub-packaging containers, buckles, strapping belts, or fresh-keeping bags arranged inside and outside the box body plate. The sub-packaging container is a unit package containing food or modified atmosphere bags.

[0010] This patented technology can realize personalized modified atmosphere packaging solutions for different food preservation conditions. It is easy to install and recyclable. However, due to the gaps between different storage compartments, the flavors of the food affect each other, resulting in the loss of the unique flavor of the food. However, when using ice packs to cool the food, the cold is unevenly distributed, and temperature-sensitive fruits and vegetables are prone to chilling damage. Summary of the invention

[0011] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a fruit and vegetable cold chain logistics microenvironment control box, which can achieve timely pre-cooling after harvesting, effectively inhibit bacteria, complete 1-MCP treatment in the first time, and realize precise temperature control during long-term logistics and distribution. At the same time, it can automatically complete spontaneous gas conditioning treatment, reduce O2 in the box, and effectively remove harmful metabolites such as ethylene and acetaldehyde, reduce the respiration rate, slow down the consumption of organic matter, and improve the logistics and storage quality of fruits and vegetables.

[0012] The present invention solves the technical problem by adopting the following technical solutions:

[0013] A fruit and vegetable cold chain logistics microenvironment control box, including a nano-TiO2 modified polyurethane insulation layer storage cavity, an upper cover body is arranged on the storage cavity, and a solar micro semiconductor refrigerator is installed on one side of the storage cavity. The cooling power comes from a solar photovoltaic panel that stores electricity from solar cells. The solar photovoltaic panel is located on the upper cover body, and inverters and batteries are arranged on both sides of the solar photovoltaic panel. The battery is connected to a DC micro vacuum pump arranged outside the upper cover body.

[0014] Moreover, inside the storage cavity, a static pressure ventilation plate is arranged on one side of the air outlet of the solar micro semiconductor refrigerator, and ventilation holes are evenly distributed on the static pressure ventilation plate.

[0015] Moreover, a UVA white light tube is arranged at the bottom of the storage cavity and below the static pressure ventilation plate.

[0016] Moreover, inside the upper cover body, 1-MCP composite antiseptic and fresh-keeping paper is arranged on both sides of the vacuum air passage formed by the DC micro vacuum pump.

[0017] Moreover, the preparation method of 1-MCP composite antiseptic fresh-keeping paper includes: firstly, evenly coating cinnamon essential oil on the core paper with a 50-mesh coating roller, coating a layer of PVA solution after drying, coating cinnamon essential oil once, drying, laminating both sides of the core paper with a hot melt adhesive film with a paper release layer, and then evenly punching holes with a hole spacing of 10 mm×10 mm and a hole diameter of 50 μm, performing quantitative drug loading treatment of 1-MCP preservative in each hole, and finally bonding the core paper and the top layer of surface paper with double-sided tape.

[0018] Moreover, a gas control valve and a temperature controller are arranged on the upper cover body, and a temperature measuring probe is arranged in the heat-insulating layer storage cavity inside the upper cover body.

[0019] Moreover, the nano-TiO2 modified polyurethane insulation layer is a nano-TiO2 modified polyurethane insulation layer material, which is composed of three layers of materials, from the inside to the outside: a modified polyurethane insulation layer with a thickness of about 50-60mm, a nano phase change energy storage layer with a thickness of 3-5mm, and an external protective layer, polyethylene or polypropylene plastic, with a thickness of about 1-2mm.

[0020] Moreover, the preparation method of the modified polyurethane thermal insulation layer comprises:

[0021] First, 0.115ml MDA, 1.665ml IPDI, 15ml DMF, and 0.02% DBTDL were dissolved in a 250ml three-necked flask, and stirred with nitrogen and a mechanical stirrer to synthesize zwitterionic polyurethane. After stirring at 70°C for 45min, 8g polycaprolactone diol was added, and then stirred at 80°C for 1h, and then 0.22mL chain extender 1,4-butanediol and 20mL viscosity retainer dimethylformamide were added, and stirring was continued for 2h. Then 0.2mL 1,3-propanesulfonate was added, and the reaction was carried out at 50°C for 12h to prepare zwitterionic polyurethane. The polyurethane was dissolved in tetrahydrofuran, and then filled with 4% TiO2 nanoparticles to prepare a series of TiO2 / polyurethane composite materials. Ultrasonic treatment was performed for 2h to make the composite uniform, and then the composite solution was heated at 50°C for 30min to evaporate the solvent to obtain a modified polyurethane insulation layer.

[0022] Moreover, the nano phase change energy storage layer components are composed of the following mass percentage formula:

[0023] Paraffin 85%, polyethylene glycol 5%, caprylic acid-myristic acid 5%, graphite 2%, carboxymethyl cellulose 3%, its melting latent heat is 200000-220000 J / kg, and the melting temperature is 34°C.

[0024] Moreover, the preparation method of the nano-TiO2 modified polyurethane thermal insulation layer includes: preparing a sheet with a thickness of 50-60 mm by high foaming of the modified polyurethane thermal insulation material, using low-density polyethylene for foaming, adding a phase change energy storage layer component during the foaming process to prepare a molded energy storage sheet with a thickness of 3-5 mm, the modified polyurethane thermal insulation layer and the nano-phase change energy storage layer are firmly bonded by a polyurethane adhesive, and then the outer protective layer is firmly bonded by a PE adhesive to form the final nano-TiO2 modified polyurethane thermal insulation layer.

[0025] The advantages and positive effects of the present invention are:

[0026] 1. The present invention breaks through the technical difficulties of traditional thermal insulation materials, which mainly include high-polyurethane and polystyrene, and innovatively develops nano-TiO2 modified polyurethane thermal insulation layer, uses titanium dioxide (TiO2) nanoparticles as ultraviolet blockers, and adds nano energy storage ions to prepare polyurethane nano-composite thermal insulation materials with strong light stability, anti-aging and antibacterial effects; at the same time, it is consistent with the phase change energy storage layer. The phase change material in the energy storage layer can absorb part of the heat infiltrated from the external environment during the phase change process, play a role in heat storage, and reduce the refrigeration load in the compartment. This structure not only plays a heat-insulating role, but also increases the thermal inertia of the enclosure structure.

[0027] 2. The present invention utilizes a solar-powered micro semiconductor refrigerator and a static pressure ventilation panel to stabilize the temperature field in the box at ±0.2°C, thereby solving the problem of accurate temperature control for a long time in the storage environment, and solving the problem of uneven temperature in the traditional ice storage and cold storage bag storage boxes causing chilling and freezing damage to fruits and rotting of fruits and vegetables in the logistics process due to insufficient refrigeration capacity. The control box is equipped with a battery, which can achieve continuous and stable cooling in the storage environment even on rainy days or in sunny conditions.

[0028] 3. The present invention can realize automatic vacuuming to reduce oxygen content through a DC micro vacuum pump. Reducing oxygen content is an effective means to inhibit the respiration of fruits after harvesting. A vacuum airway is arranged at the center of the top of the upper cover body, which is connected to the micro vacuum pump. The upper cover body and the storage box body are designed with silicone seals to achieve an automatic locking state under vacuum. Automatic vacuuming is started when the upper cover body is closed, and vacuuming is stopped when it is opened, and the vacuum degree is controlled to be 0.06-0.08MPa. The micro vacuum pump adopts a 12V DC motor with a motor length of 59.5mm, a motor diameter of 24mm, a flow rate of >1.1L / min, and the power of the vacuum pump is provided by a solar cell. After the storage cavity is deoxygenated by the vacuum pump, the internal environment gas is removed to reduce the O2 partial pressure, and hypoxia can inhibit the normal physiological activities of fruits and vegetables, inhibit the activities of corrupt microorganisms, reduce the consumption of nutrients, and delay aging.

[0029] 4. This control box is equipped with a UVA white light tube (emission wavelength 365nm) DC photovoltaic tube at the bottom of the storage cavity. The tube with this wavelength can excite the nano-TiO2 in the insulation material of the box. Under the irradiation of light with a specific wavelength of 365nm, TiO2 induces the valence band electrons (evb) to migrate to the conduction band (ecb), forming positively charged holes on the valence band (hvb+). The photogenerated electrons (evb-) and holes (hvb+) react with the water and oxygen adsorbed on the surface to generate superoxide anion radicals (O2-) and hydroxyl radicals (·OH), which have extremely strong oxidative decomposition capabilities, can destroy the chemical bonds of harmful metabolites such as ethylene and acetaldehyde produced during the storage of fruits and vegetables, and decompose them into carbon dioxide and water. It can also destroy the proteins on the cell membranes of microorganisms, and play a bactericidal role by changing the living environment of bacteria and viruses.

[0030] 5. The present invention is scientifically and reasonably designed. It uses solar micro semiconductor refrigerators, static pressure ventilation panels and DC micro vacuum pumps combined with nano-TiO2 modified polyurethane insulation materials to provide a micro-environment control box suitable for fruit and vegetable cold chain logistics, which can achieve timely pre-cooling after harvesting, effectively inhibit bacteria, complete 1-MCP treatment in the first time, and can achieve precise temperature control during long-term logistics and distribution. At the same time, it automatically completes spontaneous gas conditioning treatment, reduces O2 in the box, and effectively removes harmful metabolites such as ethylene and acetaldehyde, reduces respiration rate, slows down organic matter consumption, and improves fruit and vegetable logistics and storage quality. Through experiments, under reduced pressure conditions (0.08Mpa), the ethylene content in the box environment of Fuji apples that have been transported for 3 days is significantly lower than that of the control group (normal pressure). After 6 days of logistics distribution, the ethylene content in the box is only 24.83% of that of the control group. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a front view of the present invention;

[0032] Figure 2 for Figure 1 AA surface section view;

[0033] Figure 3 for Figure 1 BB surface cross-sectional view;

[0034] Figure 4 This is a schematic diagram of the structure of the nano-TiO2 modified polyurethane insulation layer material;

[0035] Figure 5 The diagram shows the mechanism of action of TiO2 in decomposing harmful metabolites and inactivating microorganisms;

[0036] Figure 6 This is a graph comparing the ethylene content in the storage environment during the logistics test application of the control box of the present invention. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0038] A fruit and vegetable cold chain logistics microenvironment control box, such as Figure 1-2 As shown, it includes a nano-TiO2 modified polyurethane insulation layer storage cavity 7, an upper cover body 7-1 is arranged on the storage cavity, an airtight rubber pad 10 is arranged between the upper cover body and the storage cavity, and a solar micro semiconductor refrigerator 11 is installed on one side of the storage cavity. The cooling power comes from a solar photovoltaic panel 4 that stores electricity from solar cells. The solar photovoltaic panel is located on the upper cover body, and an inverter 2 and a battery 3 are arranged on both sides of the solar photovoltaic panel. The battery is connected to a DC micro vacuum pump 5 arranged outside the upper cover body.

[0039] Inside the storage cavity, a static pressure ventilation plate 12 is provided on one side of the air outlet of the solar micro semiconductor refrigerator. Figure 3 Ventilation holes 12-1 are evenly distributed on the static pressure ventilation plate, and a UVA white light tube 14 is arranged at the bottom of the storage cavity under the static pressure ventilation plate. Inside the upper cover, 1-MCP composite antiseptic and fresh-keeping paper 9 is arranged on both sides of the vacuum air passage 6 formed by the DC micro vacuum pump, and a gas control valve 8 is arranged on the upper cover.

[0040] A temperature controller 1 is arranged on the upper part of the upper cover body, and a temperature measuring probe 13 is arranged inside the upper cover body and in the heat-insulating layer storage cavity.

[0041] The electricity stored in the battery is first converted into 12V AC voltage by a step-down circuit, and then converted into DC power by an inverter, which is supplied to the motors of the solar micro semiconductor refrigerator and the DC micro vacuum pump respectively. The cold end (evaporator) of the solar micro semiconductor refrigerator is inside the box, and the hot end (radiator) is outside the box. The connection between the refrigerator and the box is airtight and insulated to prevent cold bridges.

[0042] During the refrigeration process, the cold air blown out by the solar micro-semiconductor evaporator passes through the static pressure ventilation plate (hole spacing 80mm×80mm, hole diameter 6mm) and evenly enters the storage cavity, forming a piston flow with uniform wind speed, so that the environmental temperature field in the storage is stabilized at ±0.2℃. The start and stop of the solar micro-semiconductor refrigerator and the control of the temperature in the storage cavity are achieved through temperature measuring probes and temperature controllers.

[0043] The present invention can solve the problem of long-term precise temperature control in the storage environment, and solve the problem of cold damage and frost damage to fruits caused by uneven temperature in the preservation environment of traditional ice storage and cold storage bags, and the problem of fruit and vegetable rot in the logistics process caused by insufficient refrigeration capacity. In addition, the control box is equipped with a battery, which can achieve continuous and stable cooling in the storage cavity even in rainy days or sunny conditions.

[0044] The materials of traditional insulation boxes are mainly high polyurethane and polystyrene. Polyurethane has a lower thermal conductivity than polystyrene and has better thermal insulation performance. However, polyurethane (PU) is sensitive to ultraviolet (UV) light. Ultraviolet rays can cause polyurethane degradation, chain breaking, molecular weight reduction, and free radical generation, resulting in loss of mechanical properties and easy aging. In addition, traditional polyurethane insulation materials lack anti-fouling and anti-microbial functions. In addition, traditional polyurethane insulation boards lack the ability to store and release cold.

[0045] In view of the above problems, the storage layer insulation material of the control box of the present invention is selected as a nano-TiO2 modified polyurethane insulation layer material, such as Figure 4 The thermal insulation material is composed of three layers of materials, which are, from the inside to the outside, a modified polyurethane thermal insulation layer 17 with a thickness of about 50-60 mm, a nano phase change energy storage layer 16 with a thickness of 3-5 mm, and an external protective layer 15, polyethylene or polypropylene plastic, with a thickness of about 1-2 mm.

[0046] (1) Preparation method of modified polyurethane insulation layer

[0047] Titanium dioxide (TiO2) nanoparticles are used as UV blockers, and nano energy storage ions are added to prepare polyurethane nanocomposite thermal insulation materials with strong light stability, anti-aging and antibacterial effects. TiO2 nanoparticles have multiple characteristics such as environmental protection, low cost, odorless, UV resistance, good chemical stability, anti-aging, antioxidant, antifungal, and absorption of harmful gases. They play a role in scavenging free radicals (DPPH) by producing hydrogen in the photoelectrochemical pathway and photocatalytic process. The specific synthesis process is as follows:

[0048] First, 0.115ml MDA, 1.665ml IPDI, 15ml DMF, and 0.02% DBTDL (catalyst) were dissolved in a 250ml three-necked flask, and a zwitterionic polyurethane (ZPU) was synthesized by stirring with nitrogen and a mechanical stirrer. After stirring at 70°C for 45min, 8g polycaprolactone diol was added, and then stirred at 80°C for 1h, and then 0.22mL chain extender 1,4-butanediol and 20mL viscosity retainer dimethylformamide were added, and stirring continued for 2h. Then 0.2mL 1,3-propanesulfonic acid lactone was added, and the reaction was carried out at 50°C for 12h to prepare zwitterionic polyurethane, and the polyurethane was dissolved in tetrahydrofuran, and then filled with 4% TiO2 nanoparticles to prepare a series of TiO2 / polyurethane composite materials, ultrasonicated for 2h, and the composite was uniform, and then the composite solution was heated at 50°C for 30min, so that the solvent evaporated, and a modified polyurethane insulation layer was obtained.

[0049] (2) Preparation method of nano phase change energy storage layer components

[0050] The nano phase change energy storage layer is composed of the following formula: 85% paraffin, 5% polyethylene glycol, 5% octanoic acid-myristic acid, 2% graphite, and 3% carboxymethyl cellulose. Its melting latent heat is 200,000-220,000 J / kg, and its melting temperature is 34°C. The phase change material in the energy storage layer can absorb part of the heat infiltrated from the external environment during the phase change process, play a role in heat storage, and reduce the refrigeration load in the compartment. The structure not only plays an insulating role, but also increases the thermal inertia of the enclosing structure.

[0051] (3) Preparation method of nano-TiO2 modified polyurethane insulation layer

[0052] The modified polyurethane thermal insulation material is prepared by high foaming to form a sheet with a thickness of 50-60mm. Low-density polyethylene (LDPE) is used for foaming. Phase change energy storage layer components are added during the foaming process to prepare a formed energy storage sheet with a thickness of 3-5mm. The modified polyurethane thermal insulation layer and the nano phase change energy storage layer are firmly bonded by a polyurethane adhesive, and then the outer protective layer is firmly bonded by a PE adhesive to form the final nano TiO2 modified polyurethane thermal insulation layer.

[0053] The present invention can realize automatic vacuuming to reduce oxygen content. Reducing oxygen content is an effective means to inhibit the respiration of fruits after harvest. A vacuum airway is arranged at the center of the top of the upper cover body, which is connected to a micro vacuum pump. The upper cover body and the storage box body are designed with silicone seals, and an automatic locking state is achieved under vacuum. Automatic vacuuming is started when the upper cover body is closed, and vacuuming is stopped when it is opened, and the vacuum degree is controlled to be 0.06-0.08MPa.

[0054] The micro vacuum pump uses a 12V DC motor with a motor length of 59.5mm, a motor diameter of 24mm, a flow rate of >1.1L / min, and the power of the vacuum pump is provided by a solar cell. After the vacuum pump removes oxygen from the storage cavity, the internal environment gas is removed to reduce the O2 partial pressure, and low oxygen can inhibit the normal physiological activities of fruits and vegetables, inhibit the activities of corrupt microorganisms, reduce the consumption of nutrients, and delay aging.

[0055] After deoxygenation by the vacuum pump, a reduced-pressure storage environment is provided inside the storage environment. The low-pressure environment can promote the outward diffusion of volatile harmful gases (such as ethylene, ethanol, acetaldehyde, CO2) in fruit and vegetable tissues and reduce the physiological diseases caused by these substances. The principle is that the speed of outward diffusion of gases in the fruit tissue structure is proportional to the partial pressure difference of the gas inside and outside the tissue and its diffusion coefficient, and the diffusion coefficient is inversely proportional to the external environmental pressure; the lower the pressure, the greater the diffusion coefficient, and the more conducive it is to the discharge of harmful gases.

[0056] The bottom of the storage cavity is equipped with a UVA white light tube (emission wavelength 365nm) DC photovoltaic tube. The tube with this wavelength can excite the nano-TiO2 in the insulation material layer. Under the irradiation of light with a specific wavelength of 365nm, TiO2 induces the valence band electrons (evb) to migrate to the conduction band (ecb), forming positively charged holes on the valence band (hvb+). The photogenerated electrons (evb-) and holes (hvb+) react with the water and oxygen adsorbed on the surface to generate superoxide anion free radicals (O2 - ) and hydroxyl radicals (·OH), which have extremely strong oxidative decomposition capabilities and can destroy the chemical bonds of harmful metabolites such as ethylene and acetaldehyde produced during the storage of fruits and vegetables, decomposing them into carbon dioxide and water. They can also destroy the proteins on the cell membranes of microorganisms and play a bactericidal role by changing the living environment of bacteria and viruses ( Figure 5 ).

[0057] The present invention found in the process of applying logistics test that under reduced pressure conditions (0.08Mpa), the ethylene content in the box environment of Fuji apples transported for 3 days was significantly lower than that of the control group (normal pressure). After 6 days of logistics distribution, the ethylene content in the box was only 24.83% of that of the control group ( Figure 6 ).

[0058] Inside the upper cover, 1-MCP composite antiseptic fresh-keeping paper is arranged on both sides of the vacuum air passage formed by the DC micro vacuum pump. The preparation method of the composite antiseptic fresh-keeping paper includes: firstly, cinnamon essential oil is evenly coated on the core paper with a 50-mesh coating roller, and then a layer of PVA solution is coated after drying, and then cinnamon essential oil is coated once, and then dried. Both sides of the core paper are bonded with a hot melt adhesive film with a paper release layer, and then holes are evenly punched, with a hole spacing of 10mm×10mm and a hole diameter of 50μm. Quantitative drug loading treatment of 1-MCP preservative is carried out in each hole, and the drug loading amount is related to the weight of the fruit in the box. The dosage of 1-MCP powder is generally 0.1g / kg, and the water absorbent Cacl2 is generally 0.05g / kg. Finally, the core paper and the top surface paper are bonded and flattened with double-sided tape.

[0059] During use, due to the large respiratory heat and high field heat after fruits and vegetables are harvested, after being placed in the turnover box, condensation will occur on the inner surface of the box cover, causing the composite 1-MCP cling paper to absorb moisture, and moisture absorption will serve as the release switch of 1-MCP, releasing 1-MCP, and the present invention patent application first found that 1-MCP has an antiseptic effect in the experiment, and we found that 1-MCP treatment significantly reduced the incidence and incidence of penicillium disease in apple fruit, significantly inhibited the germination and mycelium development of penicillium spores, and affected the colony color change. After 1-MCP treatment was found by PI staining, the spore cell membrane repelled PI ability and weakened, and the spore MDA content increased, indicating that 1-MCP treatment increased the intracellular ROS level, destroyed the redox dynamic balance in the spore, and reduced the vitality of penicillium, which may be 1-MCP treatment to inhibit one of the main mechanisms of apple penicillium disease. In addition, the essential oil in the composite cling paper is more volatile under the negative pressure state in the box, and plays an antibacterial effect.

[0060] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A fruit and vegetable cold chain logistics microenvironment control box, characterized by: The invention comprises a nano-TiO2 modified polyurethane insulation layer storage cavity, an upper cover body is arranged on the storage cavity, a solar micro semiconductor refrigerator is installed on one side of the storage cavity, the cooling power of the solar photovoltaic panel is derived from the solar cell electricity storage, the solar photovoltaic panel is located on the upper cover body, an inverter and a battery are arranged on both sides of the solar photovoltaic panel, the battery is connected with a DC micro vacuum pump arranged outside the upper cover body, a static pressure ventilation plate is arranged on one side of the air outlet of the solar micro semiconductor refrigerator inside the storage cavity, ventilation holes are evenly distributed on the static pressure ventilation plate, and ventilation holes are evenly distributed on the static pressure ventilation plate. A UVA white light tube is arranged at the bottom of the ventilation plate. Inside the upper cover, 1-MCP composite antiseptic fresh-keeping paper is arranged on both sides of the vacuum airway formed by a DC micro vacuum pump. The nano-TiO2 modified polyurethane insulation layer storage cavity is a nano-TiO2 modified polyurethane insulation layer material. The insulation layer material is composed of three layers of materials, which are a modified polyurethane insulation layer with a thickness of about 50-60 mm, a nano phase change energy storage layer with a thickness of 3-5 mm, and an external protective layer, polyethylene or polypropylene plastic, with a thickness of about 1-2 mm. The preparation method of the modified polyurethane insulation layer comprises: firstly, 0.115 ml MDA, 1.665ml IPDI, 15ml DMF and 0.02% DBTDL were dissolved in a 250ml three-necked flask and stirred with nitrogen and a mechanical stirrer to synthesize zwitterionic polyurethane. After stirring at 70°C for 45min, 8g polycaprolactone diol was added and then stirred at 80°C for 1h. Then 0.22mL of chain extender 1,4-butanediol and 20mL of viscosity retainer dimethylformamide were added and stirred for 2h. Then 0.2mL of 1,3-propanesulfonate was added and reacted at 50°C for 12h to prepare zwitterionic polyurethane. The polyurethane was dissolved in tetrahydrofuran and then filled with 4% TiO2 nanoparticles to prepare a series of TiO2 / polyurethane composites. The composite was ultrasonicated for 2h to be uniformly compounded. Then the composite solution was heated at 50°C for 30min to evaporate the solvent to obtain a modified polyurethane insulation layer.

2. A fruit and vegetable cold chain logistics microenvironment control box according to claim 1, characterized in that: The preparation method of the 1-MCP composite antiseptic fresh-keeping paper comprises: firstly, uniformly coating cinnamon essential oil on a core paper with a 50-mesh coating roller, coating a layer of PVA solution after drying, coating cinnamon essential oil once, drying, laminating both sides of the core paper with a hot melt adhesive film with a paper release layer, and then uniformly punching holes with a hole spacing of 10 mm×10 mm and a hole diameter of 50 μm, performing quantitative drug loading treatment of a 1-MCP preservative in each hole, and finally bonding and flattening the core paper and the top surface paper with a double-sided adhesive.

3. The fruit and vegetable cold chain logistics microenvironment control box according to claim 1, characterized in that: A gas control valve and a temperature controller are arranged on the upper cover body, and a temperature measuring probe is arranged in the heat-insulating layer storage cavity inside the upper cover body.

4. The fruit and vegetable cold chain logistics microenvironment control box according to claim 1, characterized in that: The nano phase change energy storage layer component is composed of the following mass percentage formula: 85% paraffin, 5% polyethylene glycol, 5% octanoic acid-myristic acid, 2% graphite, and 3% carboxymethyl cellulose. Its melting latent heat is 200000-220000 J / kg and its melting temperature is 34°C.

5. The fruit and vegetable cold chain logistics microenvironment control box according to claim 1, characterized in that: The preparation method of the nano-TiO2 modified polyurethane thermal insulation layer includes: preparing a sheet with a thickness of 50-60 mm by high foaming of the modified polyurethane thermal insulation material, using low-density polyethylene for foaming, adding a phase change energy storage layer component during the foaming process to prepare a formed energy storage sheet with a thickness of 3-5 mm, the modified polyurethane thermal insulation layer and the nano-phase change energy storage layer are firmly bonded by a polyurethane adhesive, and then the external protective layer is firmly bonded by a PE adhesive to form the final nano-TiO2 modified polyurethane thermal insulation layer.

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