Packaging film material with temperature control function and preparation process thereof

Abstract

The invention relates to the field of packaging film materials, and particularly discloses a packaging film material with a temperature control function and a preparation process of the packaging film material. The packaging film material with the temperature control function comprises an upper layer and a lower layer, the lower layer comprises the following raw materials in parts by weight: 40-56 parts of a polyethylene matrix, 3-5 parts of phase change microcapsules and 4-8 parts of heat conduction fibers, core materials of the phase change microcapsules are tetradecane and paraffin, and capsule wall materials are calcium carbonate; the upper layer comprises the following raw materials in parts by weight: 45-58 parts of polyester; in addition, the preparation method has the advantage of improving the thermal insulation performance of the membrane material.

Description

Technical Field

[0001] The present application relates to the field of packaging film materials, and more specifically, to a packaging film material with a temperature control function and a preparation process thereof. Background Art

[0002] Packaging film materials are widely used in the packaging industry. They can cover goods and reduce the contact between goods and the external environment, thereby improving the loss and dust of goods during storage and transportation, and have a stabilizing effect on the state of goods. The temperature control or thermal insulation effect of the film material is also one of the important criteria for judgment. Better temperature control or thermal insulation effect can effectively reduce the deterioration of goods.

[0003] Temperature control film materials have high use value in the food industry. Common temperature control packaging on the market mainly includes traditional forms such as bubble pads, foam boxes, and ice bags. Although they can maintain the stability of the internal environment to a certain extent, the temperature control effect is generally poor. Under high or low temperature conditions, the internal temperature is easily affected by the outside world, resulting in an increased risk of product deterioration. Summary of the invention

[0004] In order to improve the thermal insulation performance of film materials, the present application provides a packaging film material with temperature control function and a preparation process thereof.

[0005] In a first aspect, the present application provides a packaging film material with a temperature control function, which adopts the following technical solution: A packaging film material with a temperature control function comprises an upper layer and a lower layer. The lower layer comprises the following raw materials in parts by weight: 40-56 parts of a polyethylene matrix, 3-5 parts of phase-change microcapsules and 4-8 parts of thermal conductive fibers, the core materials of the phase-change microcapsules are tetradecane and paraffin, and the capsule material is calcium carbonate; the upper layer comprises the following raw materials in parts by weight: 45-58 parts of polyester.

[0006] By adopting the above technical scheme, the thermal conductivity of the upper layer is poor, which can effectively reduce the heat exchange inside and outside the membrane material, thereby improving the thermal insulation effect of the membrane material. The core material of the phase change microcapsule added in the lower layer is tetradecane and paraffin. When the external temperature changes, the core material of the phase change microcapsule can undergo phase change to maintain the temperature of the lower layer and the product. The addition of thermal conductive fibers can effectively improve the heat conduction efficiency of the lower layer, so that the heat of each part of the lower layer is evenly dispersed, so that the phase change microcapsules in each part of the lower layer of the membrane material can undergo phase change and adjust the temperature in time, reducing the situation of local adjustment overload, thereby improving the temperature control effect of the membrane material.

[0007] Preferably, the preparation method of the phase change microcapsules comprises the following steps: mixing tetradecane and paraffin to obtain a core material mixed solution, mixing a surfactant, the core material mixed solution and water, stirring and emulsifying at 45-50°C for 30-40 minutes to obtain a uniform oil phase solution, dropping a calcium chloride solution into the uniform oil phase solution, and emulsifying at 45-50°C for 3 hours, then dropping a sodium carbonate solution, reacting for 6 hours, filtering, washing, and drying to obtain phase change microcapsules.

[0008] By adopting the above technical scheme, phase change microcapsules are obtained, whose core materials are tetradecane and paraffin and whose wall materials are calcium carbonate. Calcium carbonate has high strength and hardness, which can effectively improve the strength of the phase change microcapsules. At the same time, it has good thermal conductivity, so that the core material can absorb or release heat in time to undergo phase change and adjust the temperature inside the membrane material.

[0009] Preferably, the molar ratio of tetradecane to paraffin is (4.5-5.2):(4.9-5.4).

[0010] By adopting the above technical solution, the cooperation between tetradecane and paraffin can effectively improve the temperature control effect of the phase change microcapsule. The mixture of tetradecane and paraffin has a higher heat storage potential, thereby improving the temperature control effect of the phase change microcapsule.

[0011] Preferably, the mass ratio of the core material to the wall material is (0.89-1.04):(0.95-1.12).

[0012] By adopting the above technical solution, the mass ratio of the core material to the wall material is controlled, calcium carbonate is not easy to agglomerate, and the deposition rate is uniform and moderate, so that the formed phase change microcapsules have good morphology, the response rate of the phase change microcapsules to temperature is improved, and the temperature regulation ability is improved.

[0013] Preferably, nano titanium dioxide is added to the sodium carbonate solution, and the added amount of nano titanium dioxide is 2.35-4.68wt% of the wall material weight.

[0014] By adopting the above technical solution, the addition of nano-titanium dioxide can effectively increase the phase change enthalpy and coverage rate of the phase change microcapsules, thereby improving the temperature regulation function of the phase change microcapsules.

[0015] Preferably, the preparation method of the thermal conductive fiber comprises the following steps: heating polyvinyl alcohol and water to 90°C and mixing them, cooling to room temperature and stirring for 6-7 hours to obtain polyvinyl alcohol spinning solution, adding modified carbon nanotubes, ultrasonically dispersing them evenly, and then performing electrostatic spinning to obtain thermal conductive fibers.

[0016] By adopting the above technical solution, adding modified carbon nanotubes to the polyvinyl alcohol spinning solution can effectively improve the thermal conductivity of the thermal conductive fiber. At the same time, the modified carbon nanotubes have good mechanical properties and can improve the mechanical properties of the thermal conductive fiber, thereby increasing the strength of the membrane material.

[0017] Preferably, the added amount of the modified carbon nanotubes is 4.98-5.32 wt % of the polyvinyl alcohol.

[0018] By adopting the above technical solution, the addition amount of the modified carbon nanotubes is controlled, so that the modified carbon nanotubes are not easy to agglomerate, and the thermal conductivity and mechanical properties of the lower layer of the membrane material can be effectively improved.

[0019] In a second aspect, the present application provides a process for preparing a packaging film material with a temperature control function, which adopts the following technical solution: A process for preparing a packaging film material with a temperature control function comprises the following steps: Preparation of upper layer raw materials: Phase change microcapsules and thermal conductive fibers are dispersed in a polyethylene matrix and mixed evenly to obtain upper layer raw materials for use; Double-layer blow molding: The upper layer raw material and polyester are fed separately, double-layer extruded, and blown into a film to form a packaging film material with temperature control function.

[0020] By adopting the above technical solution, the prepared packaging film has good thermal insulation performance. At the same time, the lower layer of the film has good thermal conductivity and phase change enthalpy, which can regulate the temperature of the lower layer of the film and the goods inside the film, reducing the temperature change inside the film.

[0021] In summary, this application has the following beneficial effects: 1. Since the thermal conductivity of the upper layer in the present application is poor, it can effectively reduce the heat exchange inside and outside the membrane material, thereby improving the thermal insulation effect of the membrane material. The core material of the phase change microcapsule added in the lower layer is tetradecane and paraffin. When the external temperature changes, the core material of the phase change microcapsule can undergo a phase change to maintain the temperature of the lower layer and the product. The addition of thermal conductive fibers can effectively improve the heat conduction efficiency of the lower layer, so that the heat of each part of the lower layer is evenly dispersed, so that the phase change microcapsules in each part of the lower layer of the membrane material can change phases and adjust the temperature in time, reducing the situation of local adjustment overload, thereby improving the temperature control effect of the membrane material.

[0022] 2. In the present application, the core material is tetradecane and paraffin, and the wall material is calcium carbonate. The phase change microcapsules are prepared. Calcium carbonate has high strength and hardness, which can effectively improve the strength of the phase change microcapsules. At the same time, it has good thermal conductivity, so that the core material can absorb or release heat in time to undergo phase change and adjust the temperature inside the membrane material.

[0023] 3. In the present application, adding modified carbon nanotubes to the polyvinyl alcohol spinning solution can effectively improve the thermal conductivity of the thermal conductive fiber. At the same time, the modified carbon nanotubes have good mechanical properties and can improve the mechanical properties of the thermal conductive fiber, thereby increasing the strength of the membrane material. DETAILED DESCRIPTION

[0024] The present application is further described in detail below with reference to the embodiments. Preparation Example 1-12 of Phase Change Microcapsules

[0025] Preparation Example 1 The preparation method of phase change microcapsules comprises the following steps: mixing tetradecane and paraffin with a molar ratio of tetradecane to paraffin of 4.5:4.9 to obtain a core material mixed solution; mixing 2 mL of Span80, 20 g of the core material mixed solution and 100 mL of water; stirring and emulsifying at 45° C. for 40 minutes to obtain a uniform oil phase solution; dropping a calcium chloride solution into the uniform oil phase solution; emulsifying at 45-50° C. for 3 hours; dropping a sodium carbonate solution of the same amount of the substance; reacting for 6 hours; filtering, washing and drying to obtain phase change microcapsules; the mass ratio of the core material to the wall material is 0.89:0.95.

[0026] Preparation Example 2 The preparation method of phase change microcapsules comprises the following steps: mixing tetradecane and paraffin in a molar ratio of 5.2:5.4 to obtain a core material mixed solution; mixing 2 mL Tween80, 20 g of the core material mixed solution and 100 mL of water; stirring and emulsifying at 50° C. for 30 minutes to obtain a uniform oil phase solution; dropping a calcium chloride solution into the uniform oil phase solution; emulsifying at 45-50° C. for 3 hours; dropping a sodium carbonate solution of the same amount of the substance; reacting for 6 hours; filtering, washing and drying to obtain phase change microcapsules; the mass ratio of the core material to the wall material is 1.04:1.2.

[0027] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 1 is that in Preparation Example 3, the molar ratio of tetradecane to paraffin is 4.5:3.2.

[0028] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that in Preparation Example 4, the molar ratio of tetradecane to paraffin is 4.5:6.5.

[0029] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 1 is that in Preparation Example 5, the mass ratio of the core material to the wall material is 0.89:0.21.

[0030] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 1 is that in Preparation Example 6, the mass ratio of the core material to the wall material is 0.89:1.87.

[0031] Preparation Example 7 The difference between Preparation Example 7 and Preparation Example 1 is that in Preparation Example 7, an equal amount of tetradecane is used instead of the core material.

[0032] Preparation Example 8 The difference between Preparation Example 8 and Preparation Example 1 is that in Preparation Example 8, an equal amount of paraffin wax is used instead of the core material.

[0033] Preparation Example 9 The difference between Preparation Example 9 and Preparation Example 1 is that in Preparation Example 9, nano-titanium dioxide is added to the sodium carbonate solution, and the added amount of nano-titanium dioxide is 2.35 wt % of the weight of the wall material.

[0034] Preparation Example 10 The difference between Preparation Example 10 and Preparation Example 1 is that in Preparation Example 10, nano titanium dioxide is added to the sodium carbonate solution, and the added amount of nano titanium dioxide is 4.68 wt % of the weight of the wall material.

[0035] Preparation Example 11 The difference between Preparation Example 11 and Preparation Example 9 is that in Preparation Example 11, the added amount of nano titanium dioxide is 1.15 wt % of the wall material weight.

[0036] Preparation Example 12 The difference between Preparation Example 12 and Preparation Example 9 is that in Preparation Example 12, the added amount of nano-titanium dioxide is 5.91 wt % of the weight of the wall material. Preparation Examples 13-16 of Thermal Conductive Fibers

[0037] Preparation Example 13 The preparation method of modified carbon nanotubes comprises the following steps: after mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3, adding 1 g of multi-walled carbon nanotubes, condensing and refluxing at 80° C. for 3 h, cooling, centrifuging, filtering, and drying to obtain modified carbon nanotubes; The preparation method of thermal conductive fiber includes the following steps: heating polyvinyl alcohol and water to 90°C and mixing them, cooling to room temperature and stirring for 6 hours to obtain a 10wt% polyvinyl alcohol spinning solution, adding modified carbon nanotubes, wherein the added amount of the modified carbon nanotubes is 4.98wt% of the polyvinyl alcohol, and after ultrasonic dispersion, electrospinning is performed to obtain thermal conductive fiber, the spinning voltage is 15kV, the spinning rate is 0.8mL / h, and the receiving distance is 20cm.

[0038] Preparation Example 14 The preparation method of modified carbon nanotubes comprises the following steps: after mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3, adding 1.2 g of multi-walled carbon nanotubes, condensing and refluxing at 80° C. for 3 h, cooling, centrifuging, filtering, and drying to obtain modified carbon nanotubes; The preparation method of thermal conductive fiber includes the following steps: heating polyvinyl alcohol and water to 90°C and mixing them, cooling to room temperature and stirring for 7 hours to obtain a 10wt% polyvinyl alcohol spinning solution, adding modified carbon nanotubes, wherein the added amount of the modified carbon nanotubes is 5.32wt% of the polyvinyl alcohol, and after ultrasonic dispersion, electrostatic spinning is performed to obtain thermal conductive fiber, the spinning voltage is 18kV, the spinning rate is 0.9mL / h, and the receiving distance is 20cm.

[0039] Preparation Example 15 The difference between Preparation Example 15 and Preparation Example 13 is that in Preparation Example 15, the added amount of modified carbon nanotubes is 2.16 wt % of the polyethanol.

[0040] Preparation Example 16 The difference between Preparation Example 16 and Preparation Example 13 is that in Preparation Example 16, the added amount of modified carbon nanotubes is 9.25 wt % of polyvinyl alcohol. Example

[0041] In the embodiment of the present application, the polyethylene matrix is ​​SM800R produced by LG Chemical, and the polyester is R-8846 produced by Dongguan Zhongyuan New Material Technology Co., Ltd.

[0042] Example 1 A packaging film material with a temperature control function comprises an upper layer and a lower layer, wherein the lower layer comprises the following raw materials in parts by weight: 40 kg of a polyethylene matrix, 3 kg of a phase-change microcapsule and 4 kg of a thermally conductive fiber, wherein the core material of the phase-change microcapsule is tetradecane and paraffin, and the capsule material is calcium carbonate; the upper layer comprises the following raw materials in parts by weight: 45 kg of polyester, wherein the phase-change microcapsule is the phase-change microcapsule prepared in Preparation Example 1, and the thermally conductive fiber is the thermally conductive fiber prepared in Preparation Example 7.

[0043] The preparation process of the above-mentioned packaging film material with temperature control function comprises the following steps: Preparation of upper layer raw materials: Phase change microcapsules and thermal conductive fibers are dispersed in a polyethylene matrix and mixed evenly to obtain upper layer raw materials for use; Double-layer blow molding: The upper layer raw material and polyester are fed separately, double-layer extruded, and blown into a film to form a packaging film material with temperature control function.

[0044] Example 2 A packaging film material with a temperature control function comprises an upper layer and a lower layer, wherein the lower layer comprises the following raw materials in parts by weight: 56 kg of a polyethylene matrix, 5 kg of a phase-change microcapsule and 8 kg of a thermally conductive fiber, wherein the core material of the phase-change microcapsule is tetradecane and paraffin, and the capsule material is calcium carbonate; the upper layer comprises the following raw materials in parts by weight: 58 kg of polyester, wherein the phase-change microcapsules are the phase-change microcapsules prepared in Preparation Example 2, and the thermally conductive fibers are the thermally conductive fibers prepared in Preparation Example 8.

[0045] The preparation process of the above-mentioned packaging film material with temperature control function comprises the following steps: Preparation of upper layer raw materials: Phase change microcapsules and thermal conductive fibers are dispersed in a polyethylene matrix and mixed evenly to obtain upper layer raw materials for use; Double-layer blow molding: The upper layer raw material and polyester are fed separately, double-layer extruded, and blown into a film to form a packaging film material with temperature control function.

[0046] Example 3 The difference between Example 3 and Example 1 is that in Example 3, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 3.

[0047] Example 4 The difference between Example 4 and Example 1 is that in Example 4, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 4.

[0048] Example 5 The difference between Example 5 and Example 1 is that in Example 5, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 5.

[0049] Example 6 The difference between Example 6 and Example 1 is that in Example 6, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 6.

[0050] Example 7 The difference between Example 7 and Example 1 is that in Example 7, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 7.

[0051] Example 8 The difference between Example 8 and Example 1 is that in Example 8, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 8.

[0052] Example 9 The difference between Example 9 and Example 1 is that in Example 9, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 9.

[0053] Example 10 The difference between Example 10 and Example 1 is that in Example 10, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 10.

[0054] Embodiment 11 The difference between Example 11 and Example 1 is that in Example 11, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 11.

[0055] Example 12 The difference between Example 12 and Example 1 is that in Example 12, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 12.

[0056] Example 13 The difference between Example 13 and Example 1 is that in Example 13, the thermal conductive fiber is the thermal conductive fiber prepared in Preparation Example 15.

[0057] Embodiment 14 The difference between Example 14 and Example 1 is that in Example 14, the thermal conductive fiber is the thermal conductive fiber prepared in Preparation Example 16. Comparative Example

[0058] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, no phase change microcapsules are added to the lower layer.

[0059] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, the added amount of phase change microcapsules is 8 kg.

[0060] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, no thermal conductive fiber is added to the lower layer.

[0061] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, the added amount of the thermal conductive fiber is 12 kg.

[0062] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that in Comparative Example 5, phase change microcapsules and thermal conductive fibers are not added.

[0063] Test methods Packaging film materials were prepared according to the raw materials and preparation processes of Examples 1-14 and Comparative Examples 1-5, and 200 g of chicken was sealed and coated with the packaging film materials. The coated chicken and the film materials were frozen at -18°C for 24 hours, then taken out and placed in a 35°C constant temperature box. An infrared thermal imager was used to record the initial temperature of the chicken and the temperature of the chicken after 5 hours of placement. The difference between the temperature after placement and the initial temperature was calculated, and the results are shown in Table 1.

[0064] Table 1 Temperature control performance of packaging films project Temperature difference / ℃ Example 1 4.56 Example 2 5.24 Example 3 5.21 Example 4 5.28 Example 5 6.23 Example 6 5.92 Example 7 7.05 Example 8 6.94 Example 9 5.08 Example 10 5.01 Embodiment 11 3.25 Example 12 3.18 Example 13 4.38 Embodiment 14 4.42 Comparative Example 1 8.26 Comparative Example 2 7.95 Comparative Example 3 6.92 Comparative Example 4 6.12 Comparative Example 5 10.82 It can be seen from Examples 1-2, Comparative Example 5 and Table 1 that the packaging film material prepared in Examples 1-2 has good thermal insulation effects. In Examples 1-2, phase change microcapsules and thermal conductive fibers are added to the lower layer. The phase change microcapsules use calcium carbonate as the wall material to coat the core material, and the core material is tetradecane and paraffin. When the temperature changes, the core material of the phase change microcapsules can absorb or release heat by undergoing phase change, thereby regulating the temperature of the lower layer of the film material and the inside of the film material and reducing its temperature change. The thermal conductive fibers can effectively improve the next heat conduction efficiency and can conduct heat to the surroundings when the film material is locally heated, thereby prompting more phase change microcapsules to participate in temperature regulation and reducing the situation of local regulation overload, thereby improving the temperature control effect of the film material and facilitating maintaining the stability of the temperature inside the film material.

[0065] Compared with Example 1-2, the temperature difference of Example 3-4 is improved. When preparing the phase change microcapsules used in Example 3-4, the molar ratio of tetradecane to paraffin was changed. Example 7 only used tetradecane as the core material, and Example 8 only used paraffin as the core material, indicating that there is a synergistic effect between tetradecane and paraffin. Tetradecane and paraffin are mixed according to a mass ratio and used as core materials. The phase change temperature control effect is better than that of tetradecane or paraffin used alone. The mixture of tetradecane and paraffin has a higher heat storage potential, which can effectively improve the temperature control effect of the phase change microcapsules.

[0066] Compared with Example 1-2, the temperature difference of Example 5-6 is improved. During the preparation of the phase change microcapsules used in Example 5-6, the mass ratio of the core material to the wall material was changed, indicating that the mass ratio of the core material to the wall material has an impact on the temperature control effect of the phase change microcapsules. An increase in the mass ratio may easily lead to too little wall material, incomplete coating of the core material or poor coating morphology. A decrease in the mass ratio may easily lead to excessive deposition of calcium carbonate, thereby making the morphology of the phase change microcapsules uneven or agglomerating, reducing the response rate of the phase change microcapsules and reducing their temperature control ability.

[0067] Compared with Example 1-2, the temperature difference of Example 9-10 is reduced. In Example 9-10, nano titanium dioxide is added to the sodium carbonate solution, which shows that nano titanium dioxide can improve the temperature control effect of the phase change microcapsules. The addition of nano titanium dioxide can increase the particle size of the phase change microcapsules and improve the morphological uniformity of the phase change microcapsules, thereby effectively improving the phase change enthalpy and coverage rate of the phase change microcapsules, thereby improving the temperature regulation function of the phase change microcapsules.

[0068] Compared with Examples 9-10, the temperature difference of Example 11-12 is improved. In Example 11-12, the amount of nano-titanium dioxide added is changed. When the amount of nano-titanium dioxide added is reduced, the effect of improving the morphology of the phase change microcapsules decreases, and the phase change enthalpy and coverage of the phase change microcapsules are reduced. When the amount of nano-titanium dioxide added is increased, the morphology of the deposited wall material of the phase change microcapsules is easily destroyed, thereby causing the phase change microcapsules to stick together, break, etc., and weakening the temperature control effect of the phase change microcapsules.

[0069] Compared with Example 1-2, the temperature difference of Example 13-14 is improved. When preparing the thermal conductive fiber used in Example 13-14, the addition amount of modified carbon nanotubes in the polyvinyl alcohol spinning solution is changed. The modified carbon nanotubes can effectively improve the thermal conductivity and mechanical properties of the thermal conductive fiber. When the addition amount is too small, the thermal conductivity effect of the thermal conductive fiber is easily reduced. When the addition amount is too large, the modified carbon nanotubes are easy to agglomerate in the polyvinyl alcohol spinning solution and are unevenly dispersed, which affects the effect of electrospinning, thereby reducing the performance of the thermal conductive fiber.

[0070] Compared with Example 1-2, the temperature difference of Comparative Example 1-2 is improved. No phase change microcapsules are added in Comparative Example 1, and the amount of phase change microcapsules added is increased in Comparative Example 2, which shows that the amount of phase change microcapsules added affects the temperature control effect of the film material. No phase change microcapsules are added in Comparative Example 1, so that the film material of Comparative Example 1 cannot absorb or release heat to adjust the temperature through phase change when the temperature changes. The amount of phase change microcapsules added in Comparative Example 2 is increased, which easily leads to uneven distribution of phase change microcapsules, reduces the mechanical properties of the film material, and affects the heat transfer and response rate of the phase change microcapsules, thereby reducing the temperature control effect of the film material.

[0071] Compared with Examples 1-2, the temperature difference of Comparative Examples 3-4 is improved. No thermal conductive fiber is added in Comparative Example 3, and the amount of thermal conductive fiber added is increased in Comparative Example 4, which shows that the amount of thermal conductive fiber added affects the temperature control effect of the membrane material. No thermal conductive fiber is added in Comparative Example 3, which makes it difficult for the membrane material of Comparative Example 3 to quickly conduct the heat of the heated part to the outside when the temperature changes, thereby weakening the effect of the phase change microcapsules. The amount of thermal conductive fiber added in Comparative Example 4 is increased, which easily leads to uneven distribution of the thermal conductive fiber, weakening the thermal conductivity of the lower layer of the membrane material, thereby reducing the temperature control effect of the membrane material.

[0072] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A packaging film material with temperature control function, characterized in that: It comprises an upper layer and a lower layer, wherein the lower layer comprises the following raw materials in parts by weight: 40-56 parts of a polyethylene matrix, 3-5 parts of phase-change microcapsules and 4-8 parts of thermal conductive fibers, wherein the core material of the phase-change microcapsules is tetradecane and paraffin, and the capsule material is calcium carbonate; The upper layer comprises the following raw materials in parts by weight: 45-58 parts of polyester.

2. The packaging film material with temperature control function according to claim 1, characterized in that: The preparation method of the phase change microcapsule comprises the following steps: mixing tetradecane and paraffin to obtain a core material mixed solution, mixing a surfactant, the core material mixed solution and water, stirring and emulsifying at 45-50° C. for 30-40 minutes to obtain a uniform oil phase solution, dripping a calcium chloride solution into the uniform oil phase solution, emulsifying at 45-50° C. for 3 hours, dripping a sodium carbonate solution, reacting for 6 hours, filtering, washing and drying to obtain the phase change microcapsule.

3. The packaging film material with temperature control function according to claim 1, characterized in that: The molar ratio of tetradecane to paraffin is (4.5-5.2):(4.9-5.4).

4. The packaging film material with temperature control function according to claim 1, characterized in that: The mass ratio of the core material to the wall material is (0.89-1.04):(0.95-1.12).

5. The packaging film material with temperature control function according to claim 2, characterized in that: Nano titanium dioxide is added to the sodium carbonate solution, and the added amount of the nano titanium dioxide is 2.35-4.68wt% of the wall material.

6. The packaging film material with temperature control function according to claim 1, characterized in that: The preparation method of the thermal conductive fiber comprises the following steps: heating polyvinyl alcohol and water to 90° C. and mixing them, cooling to room temperature and stirring for 6-7 hours to obtain polyvinyl alcohol spinning solution, adding modified carbon nanotubes, ultrasonically dispersing them uniformly, and then performing electrostatic spinning to obtain the thermal conductive fiber.

7. The packaging film material with temperature control function according to claim 6, characterized in that: The added amount of the modified carbon nanotubes is 4.98-5.32 wt % of the polyvinyl alcohol.

8. The process for preparing the packaging film material with temperature control function according to any one of claims 1 to 7, characterized in that: The following steps are involved: Preparation of upper layer raw materials: Phase change microcapsules and thermal conductive fibers are dispersed in a polyethylene matrix and mixed evenly to obtain upper layer raw materials for use; Double-layer blow molding: The upper layer raw material and polyester are fed separately, double-layer extruded, and blown into a film to form a packaging film material with temperature control function.