Nano-microsphere structure food-grade cold storage agent and packaging structure and preparation method of nano-microsphere structure food-grade cold storage agent

Abstract

The invention relates to the technical field of cold storage agents for cold chain transportation, in particular to a food-grade cold storage agent with a nano-microsphere structure and a packaging structure and a preparation method of the food-grade cold storage agent with the nano-microsphere structure, and the food-grade cold storage agent with the nano-microsphere structure comprises the following components in percentage by weight: 2.5%-22.4% of sodium chloride, 0.01%-10% of sodium carboxymethyl cellulose, 3%-20% of fructose, 1%-20% of glycerol, 0.1%-8% of borax and the balance of water. The phase change temperature of the cold storage agent can be adjusted by adjusting the concentration of sodium chloride, so that cold chain transportation of different requirements can be met, chain-shaped sodium carboxymethyl cellulose molecules and fructose molecules form a three-dimensional spherical structure in a salt solution through hydrogen bond interaction, the spherical structure contains a large amount of sodium chloride and water molecules, and the sodium chloride and the water molecules are separated from each other. A three-dimensional supramolecular structure is formed, and the three-dimensional supramolecular structure needs additional energy to be cracked when the coolant is converted from a solid state to a liquid state, so that the phase change latent heat of the coolant is greater than 245kJ / kg due to the microsphere structure, the volume change rate is less than 2% during liquid-solid phase change, and the stability of each component in the solid-liquid state conversion process can be maintained.

Description

Technical Field

[0001] The invention relates to the technical field of refrigerants for cold chain transportation, and in particular to a food-grade refrigerant with a nano-microsphere structure, a packaging structure and a preparation method thereof. Background Art

[0002] With the continuous development of my country's agricultural product circulation industry, various agricultural product circulation methods have emerged, which has also put forward higher requirements for the development of agricultural product cold chain logistics industry. If the development of agriculture is to be on the trend and track, it needs an industrial chain to escort it, and cold chain logistics is undoubtedly this chain.

[0003] Cold Chain Logistics refers to a systematic project that keeps refrigerated and frozen foods in a specified low-temperature environment throughout the production, storage, transportation, sales, and before consumption to ensure food quality and reduce food loss. It was established with the advancement of science and technology and the development of refrigeration technology. It is a low-temperature logistics process based on refrigeration technology and using refrigeration technology as a means.

[0004] Phase change materials (PCMs) have been a hot topic in recent research on energy utilization and materials science at home and abroad. Phase change materials are materials that can absorb heat from or release heat to the environment during their phase change, thereby achieving the purpose of energy storage and release, and solving the contradiction between energy supply and demand in time and space. Utilizing this characteristic, PCM has broad application prospects in the fields of solar energy utilization, "peak shifting and valley filling" of electricity, recycling of waste cooling and waste heat, energy-saving building materials, energy saving of air conditioners, and food preservation. At the same time, because the temperature is approximately constant during phase change, it can be used to adjust and control the temperature of the surrounding environment, and can be reused many times.

[0005] At present, my country's overall understanding of the role and significance of phase change cold storage materials is not high. There is little research on phase change cold storage agents, and there is a lack of systematic research and development. This is the biggest problem facing my country in the field of phase change cold storage material research. Among the several cold storage agents that have been developed, there are problems such as high supercooling, poor thermal conductivity, and unadjustable phase change temperature. These factors have led to the phase change cold storage agent not being able to play its due role. Summary of the invention

[0006] In view of the above defects or deficiencies in the prior art, it is desirable to provide a food-grade refrigerant with a nano-microsphere structure and a packaging structure and a preparation method thereof to solve at least one of the above problems.

[0007] In a first aspect, the present invention provides a food-grade refrigerant with a nano-microsphere structure, wherein the refrigerant is composed of sodium chloride, sodium carboxymethyl cellulose, fructose and water, and the weight percentage of each component is as follows:

[0008]

[0009] Preferably, the sodium carboxymethyl cellulose is formed by connecting a plurality of modified glucose molecules via β-1,4-glycosidic bonds.

[0010] In a second aspect, the present invention provides a packaging structure for a food-grade refrigerant with a nano-microsphere structure, which is used to package the food-grade refrigerant with a nano-microsphere structure as described above, wherein the packaging structure comprises a plurality of filling columns for filling the refrigerant, and the plurality of filling columns are distributed in a multi-point matrix.

[0011] Preferably, the packaging structure is made of a plastic composite film composed of PE and nylon materials.

[0012] In a third aspect, the present invention provides a method for preparing a food-grade refrigerant having a nano-microsphere structure, comprising:

[0013] The water is subjected to coarse filtration, fine filtration, reverse osmosis and ultraviolet sterilization to obtain pure water;

[0014] Mixing sodium chloride and the purified water for halogenation and stirring to obtain a halogenated solution;

[0015] Mixing sodium carboxymethyl cellulose and the halogenated solution and stirring them homogeneously to obtain a homogeneous solution;

[0016] The fructose and the homogenous solution are mixed, heated and stirred to obtain the cooling agent.

[0017] Preferably, the refrigerant is used in cold chain transportation with a phase change temperature of -10°C to -2°C.

[0018] The beneficial effects of the present invention are:

[0019] The present invention can adjust the phase change temperature of the refrigerant by adjusting the concentration of sodium chloride, thereby meeting cold chain transportation requirements of different needs.

[0020] The chain-like sodium carboxymethyl cellulose molecules contain more carboxyl groups and hydroxyl groups. These carboxyl groups and hydroxyl groups interact with the hydroxyl groups in the fructose molecules through hydrogen bonds, connecting the chain-like sodium carboxymethyl cellulose into a network of supramolecular structures. This two-dimensional network supramolecular structure curls and folds in a salt solution to form a three-dimensional spherical structure. This spherical structure contains a large number of sodium chloride and water molecules, forming a three-dimensional supramolecular structure. When changing from solid to liquid, this three-dimensional supramolecular structure requires additional energy to be cracked. Therefore, this microsphere structure makes the phase change latent heat of the coolant greater than 245kJ / kg, the volume change rate is less than 2% during the liquid-solid phase change, and can maintain the stability of each component during the solid-liquid conversion process.

[0021] The present invention adopts a matrix-type multi-point cyclone cold-release packaging structure, so that when the endothermic hot spots contact the surface of the preserved items, they absorb heat in a matrix manner through the contact points, and at the same time, cold air of a set temperature is quickly released around the endothermic hot spots. The adjacent cold air converges in the cyclone point to form a cold air vortex. The vortices in the adjacent cyclone points in the airway interfere with each other to form an airflow, and the airflow exchanges with the hot air dissipated by the preserved items along the airway, forming a planar airflow to form a cold air protection layer on the surface of the preserved object, thereby realizing the entire point-to-surface heat exchange process. DETAILED DESCRIPTION

[0022] In the following description, certain specific details are included to provide a comprehensive understanding of each disclosed embodiment. However, one skilled in the relevant art will recognize that the embodiments can be implemented without one or more of these specific details, but with other methods, components, materials, etc.

[0023] Unless otherwise required in this application, throughout the specification and the claims that follow, the words "including" and "comprising" should be interpreted in an open, inclusive sense, ie, "including, but not limited to."

[0024] In the following examples, unless otherwise specified, all raw materials are commercially available products.

[0025] In Examples 1 to 8, a food-grade refrigerant with a nano-microsphere structure is provided respectively. The specific components of the refrigerant and the weight percentage of each component are shown in Table 1.

[0026] Table 1

[0027]

[0028]

[0029] Example 1

[0030] The preparation of the coolant in each embodiment includes the following steps:

[0031] S1, subjecting the water to coarse filtration, fine filtration, reverse osmosis and ultraviolet sterilization treatment to obtain pure water;

[0032] S2, mixing sodium chloride and the pure water to perform halogenation and stirring to obtain a halogenated solution;

[0033] S3, mixing sodium carboxymethyl cellulose and the halogenated solution and stirring them homogeneously to obtain a homogeneous solution;

[0034] S4, mixing fructose and the homogenous solution, heating and stirring to obtain the coolant.

[0035] The phase change latent heat and phase change temperature of the nano-microsphere refrigerant prepared in each embodiment of the present invention were tested using a differential scanning calorimeter. The test results are shown in Table 2.

[0036] Table 2

[0037]

[0038] It can be seen from Table 2 that the nano-microsphere structured food-grade refrigerant provided in the embodiment of the present invention has a high phase change latent heat and thermal conductivity. The phase change latent heat is greater than 245 kJ / kg, which greatly improves the cold storage efficiency and heat transfer rate of the refrigerant. The phase change temperature is adjustable at -10°C to -2°C, which can meet the cold chain transportation with a phase change temperature of -10°C to -2°C.

[0039] Example 9

[0040] The present embodiment provides a packaging structure of a food-grade refrigerant with a nano-microsphere structure, which is used to package the food-grade refrigerant with a nano-microsphere structure as described in Embodiments 1 to 8. The packaging structure includes a plurality of filling columns for filling the refrigerant, and the plurality of filling columns are distributed in a multi-point matrix. The material of the packaging structure is a plastic composite film composed of PE and nylon materials.

[0041] Specifically, a matrix multi-point cyclone cooling release packaging structure is adopted, so that when the absorption hot spots contact the surface of the preserved items, they absorb heat in a matrix manner through the contact points, and at the same time, cold air of a set temperature is quickly released around the absorption hot spots. The adjacent cold air converges in the cyclone point to form a cold air vortex. The vortices in the adjacent cyclone points in the airway interfere with each other to form an airflow, and the airflow exchanges with the hot air dissipated by the preserved items along the airway, forming a surface airflow to form a cold air protection layer on the surface of the preserved object, thereby realizing the entire heat and cold exchange process from point to surface.

[0042] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A food-grade refrigerant with nano-microsphere structure, It is characterized in that The coolant is composed of sodium chloride, sodium carboxymethyl cellulose, fructose and water, and the weight percentage of each component is as follows:

2. The nano-microsphere structured food-grade coolant according to claim 1, It is characterized in that The sodium carboxymethyl cellulose is formed by connecting a plurality of modified glucose molecules through β-1,4-glycosidic bonds.

3. The nano-microsphere structured food-grade coolant according to claim 1, It is characterized in that The refrigerant is used in cold chain transportation with a phase change temperature of -10°C to -2°C.

4. A packaging structure of a food-grade refrigerant with a nano-microsphere structure, It is characterized in that Used to package the nano-microsphere structured food-grade coolant as claimed in any one of claims 1 to 4, the packaging structure comprises a plurality of filling columns for filling the coolant, and the plurality of filling columns are distributed in a multi-point matrix.

5. The packaging structure of the food-grade refrigerant with nano-microsphere structure according to claim 4, It is characterized in that The material of the packaging structure is a plastic composite film composed of PE and nylon materials.

6. A method for preparing a food-grade refrigerant with a nano-microsphere structure, It is characterized in that include: The water is subjected to coarse filtration, fine filtration, reverse osmosis and ultraviolet sterilization to obtain pure water; Mixing sodium chloride and the purified water for halogenation and stirring to obtain a halogenated solution; Mixing sodium carboxymethyl cellulose and the halogenated solution and stirring them homogeneously to obtain a homogeneous solution; The fructose and the homogenous solution are mixed, heated and stirred to obtain the cooling agent.

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