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CN-121975500-A - Cold-preserving phase-change material and fresh packaging structure using same

CN121975500ACN 121975500 ACN121975500 ACN 121975500ACN-121975500-A

Abstract

The invention discloses a cold insulation phase-change material and a fresh packaging structure applied by the same, which belong to a fresh packaging material, and comprise, by weight, 96% -97% of a phase-change composition, 1.7% -1.9% of nano silicon oxide, 0.5% -0.7% of butyl hydroxy anisole, 0.3% -0.5% of polyethylene glycol, 0.1% -0.3% of polybutylene succinate and 0.4% -0.6% of a silane coupling agent, wherein the phase-change composition comprises methyl palmitate and ethyl stearate, and the mass ratio of the methyl palmitate to the ethyl stearate is 6-7:3-4. By redesigning the formula of the phase-change material, the precise temperature control of 0.5-8 ℃ can be realized when the phase-change material is applied, the latent heat is 188+/-2J/g, the diversified fresh-keeping requirements are met, the thicknesses of the formula of the phase-change material and the cold-keeping layer can be finely adjusted on the basis of a fresh packaging structure, the phase-change material is suitable for storage and transportation of fresh foods of different types, and the phase-change material composite layer can be processed into packages of various forms.

Inventors

  • LEI XIANZHANG
  • LAN TIAN
  • XIAO YAN
  • He Kunsong

Assignees

  • 成都相变科技有限公司

Dates

Publication Date
20260505
Application Date
20260209

Claims (7)

  1. 1. The cold-insulation phase-change material is characterized by comprising, by weight, 96% -97% of a phase-change composition, 1.7% -1.9% of nano silicon oxide, 0.5% -0.7% of butyl hydroxy anisole, 0.3% -0.5% of polyethylene glycol, 0.1% -0.3% of polybutylene succinate and 0.4% -0.6% of a silane coupling agent, wherein the phase-change composition comprises methyl palmitate and ethyl stearate, and the mass ratio of the methyl palmitate to the ethyl stearate is 6-7:3-4; The cold insulation phase change material is prepared according to the following steps: After weighing raw materials, adding methyl palmitate and ethyl stearate into a stainless steel reaction kettle according to a formula proportion, heating to above 72 ℃, and uniformly stirring to obtain a raw material mixture; Sequentially adding nano silicon oxide, butyl hydroxy anisole, polyethylene glycol, polybutylene succinate and a silane coupling agent into the raw material mixture according to a formula, and then performing ultrasonic dispersion to ensure that the average particle size of the materials added in the step is less than 45nm to obtain a primary mixture; and then cooling the primary mixture to below 27 ℃, transferring to a vacuum drying oven, standing for 24-48h, and removing micro bubbles to obtain the cold insulation phase change material.
  2. 2. The cold-resistant phase change material according to claim 1, wherein the preliminary mixture is further sheared and stirred under the protection of nitrogen by using a high-shearing homogenizer, and the refined additive particles are transferred to a vacuum drying oven.
  3. 3. The cold-proof phase change material according to claim 1 or 2, wherein the cooling rate of the preliminary mixture before transferring to a vacuum drying oven is 1.0-1.2 ℃ per minute.
  4. 4. A fresh packaging structure is characterized by comprising a cold insulation layer, wherein a blocking layer is arranged on the inner side of the cold insulation layer, an inner liner layer is arranged on the inner side of the blocking layer, a protection layer is arranged on the outer side of the cold insulation layer, and the protection layer and the cold insulation layer are fixed together through an adhesive layer; The cold insulation layer is the cold insulation phase change material according to any one of claims 1 to 3, the barrier layer is ethylene-vinyl alcohol copolymer, the inner liner layer is food-grade polypropylene, the protective layer is high-density polyethylene, and the adhesive layer is modified polyolefin; The fresh packaging structure is prepared through the following steps: After raw materials are prepared, extruding the inner liner layer, the barrier layer, the cold insulation layer, the adhesive layer and the protective layer at one time by using a five-layer coextrusion machine to obtain a composite layer; and then cooling and shaping the composite layer, cutting, performing vacuum compression molding, and then manufacturing the composite layer into any fresh packaging structure of a strip shape, a box shape and a tray shape.
  5. 5. The fresh packaging structure according to claim 4, wherein the method comprises cooling and shaping the composite layer by using three-stage cooling rollers, wherein the cooling temperature of the three-stage cooling rollers is 10 ℃ in the first stage, 8 ℃ in the second stage and 6 ℃ in the third stage, and the total cooling time is 45 seconds.
  6. 6. The fresh packaging structure according to claim 4 or 5, wherein the extrusion temperatures of the inner liner, the barrier layer, the cold-keeping layer, the adhesive layer and the protective layer in the method are 160-163 ℃, 175-178 ℃, 145-148 ℃, 160-162 ℃ and 170-173 ℃.
  7. 7. The fresh packaging structure according to claim 4, wherein the cold insulation phase change material and the low density polyethylene are melt-mixed as the raw material of the cold insulation layer before extrusion by using a five-layer co-extruder, and particles of the cold insulation phase change material account for 55-65% of the volume of the low density polyethylene after the melt-mixing.

Description

Cold-preserving phase-change material and fresh packaging structure using same Technical Field The invention relates to a fresh packaging material, in particular to a cold-preserving phase-change material and a fresh packaging structure applied by the same. Background Fresh keeping of fresh food is of vital importance in the food supply chain, directly affecting food quality and safety. Traditional preservation methods rely mainly on external cooling equipment or a separate phase change material package, but suffer from significant drawbacks. External cooling devices require continuous power supply, consume high energy and are difficult to maintain at a stable low temperature in long haul or no power support environments. Although the independent PCM bag is portable, leakage or displacement is easy to occur, so that uneven cooling is caused, and even food can be polluted due to material damage. In addition, the phase transition temperature and thermal stability of commercial PCM are often of a general design, and it is difficult to meet specific temperature control requirements for different raw foods. The energy consumption and operational complexity of conventional methods in long haul transport are major bottlenecks. In recent years, the market has attempted to combine commercial PCM with packaging materials by physical mixing or surface coating to improve the preservation efficiency. However, commercial PCM (such as paraffin-based PCM) has low latent heat value (about 150J/g) and poor cycle stability due to the general design, and cannot realize customized temperature control. In addition, physical mixing or coating processes result in a PCM that is not tightly bonded to the packaging material, has low thermal conductivity (about 0.15W/mk), and is not well distributed, increasing the risk of leakage. The manufacturing process of the methods is complex, the production cost is high, and the methods are difficult to apply on a large scale. In addition, the prior art still depends on commercial PCM, lacks targeted optimization, has insufficient integration degree, and is difficult to consider heat management efficiency, structural stability and production convenience. And performance degradation of phase change material packages in long-term use is a critical issue. Thus, a solution that breaks through the conventional limitations is needed. Disclosure of Invention One of the purposes of the present invention is to provide a cold insulation phase change material and a fresh packaging structure using the same, so as to solve the technical problems that the similar fresh transportation mode in the prior art cannot meet the specific temperature control requirement, the performance is insufficient, the manufacturing process is complex, and the like. In order to solve the technical problems, the invention adopts the following technical scheme: The invention provides a cold insulation phase change material which comprises, by weight, 96% -97% of a phase change composition, 1.7% -1.9% of nano silicon oxide, 0.5% -0.7% of butyl hydroxy anisole, 0.3% -0.5% of polyethylene glycol, 0.1% -0.3% of polybutylene succinate and 0.4% -0.6% of a silane coupling agent, wherein the phase change composition comprises 6-7:3-4 of methyl palmitate and ethyl stearate. The cold insulation phase change material is prepared by weighing raw materials, adding methyl palmitate and ethyl stearate into a stainless steel reaction kettle according to a formula proportion, heating to above 72 ℃, and uniformly stirring to obtain a raw material mixture. Sequentially adding nano silicon oxide, butyl hydroxy anisole, polyethylene glycol, polybutylene succinate and a silane coupling agent into a raw material mixture according to a formula, performing ultrasonic dispersion to ensure that the average particle size of the materials added in the step is less than 45nm to obtain a preliminary mixture, cooling the preliminary mixture to below 27 ℃, transferring the preliminary mixture to a vacuum drying oven, standing for 24-48h, and removing micro bubbles to obtain the cold insulation phase change material. Preferably, the further technical scheme is that the preliminary mixture is further sheared and stirred by a high shearing homogenizer under the protection of nitrogen, and the refined additive particles are transferred to a vacuum drying oven. A further technical scheme is that the cooling rate of the preliminary mixture before being transferred to a vacuum drying oven is 1.0-1.2 ℃ per minute. The invention further provides a fresh packaging structure which comprises a cold insulation layer, wherein a blocking layer is arranged on the inner side of the cold insulation layer, an inner liner layer is arranged on the inner side of the blocking layer, a protection layer is arranged on the outer side of the cold insulation layer, the protection layer and the cold insulation layer are fixed together through an adhesive layer, the cold insulation layer is