A packaging film material with temperature control function and its preparation process

Abstract

This application relates to the field of packaging film materials, and specifically discloses a packaging film material with temperature control function and its preparation process. A packaging film material with temperature control function and its preparation process include an upper layer and a lower layer. The lower layer comprises the following raw materials in parts by weight: 40 - 56 parts of polyethylene matrix, 3 - 5 parts of phase change microcapsules, and 4 - 8 parts of heat conductive fibers. The core material of the phase change microcapsules is tetradecane and paraffin, and the shell material is calcium carbonate. The upper layer comprises the following raw materials in parts by weight: 45 - 58 parts of polyester. In addition, the preparation method of this application has the advantage of improving the heat preservation performance of the film material.

Description

Technical Field

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

[0002] Packaging film materials are widely used in the packaging industry. They can wrap commodities, reduce the contact between commodities and the external environment, thereby reducing the loss and dust of commodities during storage and transportation, and having a stabilizing effect on the state of commodities. The temperature control effect or heat preservation effect of the film material is also one of the important evaluation criteria. A better temperature control effect or heat preservation effect can effectively reduce the deterioration of commodities.

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

[0004] In order to improve the heat preservation performance of the film material, this application provides a packaging film material with temperature control function and its preparation process.

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

[0006] By adopting the above technical solution, the upper layer has poor thermal conductivity, which can effectively reduce the heat exchange inside and outside the film material, thereby improving the heat preservation effect of the film material. In the lower layer, the core materials of the added phase change microcapsules are tetradecane and paraffin. When the external temperature changes, the core materials of the phase change microcapsules can undergo a phase change to maintain the temperature of the lower layer and the commodities. The addition of heat-conducting fibers can effectively improve the heat conduction efficiency of the lower layer, making the heat of each part of the lower layer disperse evenly, enabling the phase change microcapsules in each part of the lower layer of the film material to undergo a phase change in time and adjust the temperature, reducing the situation of local regulation overload, thereby improving the temperature control effect of the film material.

[0007] Preferably, the preparation method of the phase change microcapsules comprises the following steps: mixing tetradecane and paraffin wax to obtain a core material mixed solution; after mixing a surfactant, the core material mixed solution and water, stirring and emulsifying at 45-50 °C for 30-40 min 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 h, then dropping a sodium carbonate solution, reacting for 6 h, followed by suction filtration, washing and drying to obtain the phase change microcapsules.

[0008] By adopting the above technical solution, phase change microcapsules with tetradecane and paraffin wax as the core material and calcium carbonate as the wall material are prepared. Calcium carbonate has relatively high strength and hardness, which can effectively improve the strength of the phase change microcapsules. Meanwhile, it has good thermal conductivity, enabling the core material to absorb or release heat in a timely manner to undergo a phase change and regulate the temperature inside the film material.

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

[0010] By adopting the above technical solution, tetradecane and paraffin wax cooperate with each other to effectively improve the temperature control effect of the phase change microcapsules. The mixture of tetradecane and paraffin wax has a higher heat storage potential, thereby improving the temperature control effect of the phase change microcapsules.

[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, by controlling the mass ratio of the core material to the wall material, calcium carbonate is not prone to agglomeration, and the deposition rate is uniform and moderate, enabling the formed phase change microcapsules to have good morphology, improving the response rate of the phase change microcapsules to temperature, and enhancing the temperature regulation ability.

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

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

[0015] Preferably, the preparation method of the heat-conducting fiber comprises the following steps: heating polyvinyl alcohol and water to 90 °C for mixing, cooling to room temperature and then stirring for 6-7 h to obtain a polyvinyl alcohol spinning solution; adding modified carbon nanotubes, dispersing evenly by ultrasonic treatment, and then performing electrospinning to obtain the heat-conducting fiber.

[0016] By adopting the above technical solution, adding modified carbon nanotubes to the polyvinyl alcohol spinning solution can effectively improve the heat conduction efficiency of the heat-conducting fiber. At the same time, the modified carbon nanotubes have good mechanical properties and can improve the mechanical properties of the heat-conducting fiber, thereby enhancing the strength of the film material.

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

[0018] By adopting the above technical solution, controlling the addition amount of the modified carbon nanotubes can prevent the modified carbon nanotubes from agglomerating easily and can effectively improve the heat conduction performance and mechanical properties of the lower layer of the film material.

[0019] In a second aspect, the present application provides a preparation process for a packaging film material with a temperature control function, adopting the following technical solution:

[0020] A preparation process for a packaging film material with a temperature control function includes the following steps:

[0021] Preparation of the upper layer raw material: Dispersing the phase change microcapsules and the heat-conducting fiber in the polyethylene matrix, mixing evenly, and preparing the upper layer raw material for standby.

[0022] Double-layer blow molding: Feeding the upper layer raw material and the polyester separately, performing double-layer extrusion, and blow molding to form a film, thereby forming a packaging film material with a temperature control function.

[0023] By adopting the above technical solution, the prepared packaging film material has good heat insulation performance. At the same time, the lower layer of the film material has good heat conduction efficiency and phase change enthalpy, which can regulate the temperature of the lower layer of the film material and the goods inside the film material, and reduce the temperature change inside the film material.

[0024] In summary, the present application has the following beneficial effects:

[0025] 1. Since the upper layer of the present application has poor heat conductivity, it can effectively reduce the heat exchange inside and outside the film material, thereby improving the heat preservation effect of the film material. The core materials of the phase change microcapsules added to the lower layer are tetradecane and paraffin. When the external temperature changes, the core materials of the phase change microcapsules can undergo a phase change to maintain the temperature of the lower layer and the goods. The addition of the heat-conducting fiber can effectively improve the heat conduction efficiency of the lower layer, making the heat of each part of the lower layer evenly distributed, enabling the phase change microcapsules in each part of the lower layer of the film material to undergo a phase change in a timely manner and adjust the temperature, reducing the situation of local adjustment overload, thereby improving the temperature control effect of the film material.

[0026] 2. In this application, the core material of the phase change microcapsules prepared is tetradecane and paraffin, and the wall material is 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, enabling the core material to absorb or release heat in a timely manner to undergo a phase change and adjust the temperature inside the membrane material.

[0027] 3. Adding modified carbon nanotubes to the polyvinyl alcohol spinning solution in this application can effectively improve the thermal conductivity efficiency of the thermal conductive fibers. At the same time, the modified carbon nanotubes have good mechanical properties, which can improve the mechanical properties of the thermal conductive fibers, thereby enhancing the strength of the membrane material. Specific Embodiments

[0028] The following further elaborates on this application in conjunction with examples.

[0029] Preparation Examples 1 - 12 of Phase Change Microcapsules

[0030] Preparation Example 1

[0031] The preparation method of the phase change microcapsules includes the following steps: Mix tetradecane and paraffin, with the molar ratio of tetradecane to paraffin being 4.5:4.9, to obtain a core material mixed solution. After mixing 2 mL of Span80, 20 g of the core material mixed solution, and 100 mL of water, stir and emulsify at 45°C for 40 min to obtain a uniform oil-phase solution. Dropwise add calcium chloride solution to the uniform oil-phase solution, and after emulsifying at 45 - 50°C for 3 h, dropwise add the same amount of sodium carbonate solution. After reacting for 6 h, filter by suction, wash, and dry to obtain the phase change microcapsules, with the mass ratio of the core material to the wall material being 0.89:0.95.

[0032] Preparation Example 2

[0033] The preparation method of the phase change microcapsules includes the following steps: Mix tetradecane and paraffin, with the molar ratio of tetradecane to paraffin being 5.2:5.4, to obtain a core material mixed solution. After mixing 2 mL of Tween80, 20 g of the core material mixed solution, and 100 mL of water, stir and emulsify at 50°C for 30 min to obtain a uniform oil-phase solution. Dropwise add calcium chloride solution to the uniform oil-phase solution, and after emulsifying at 45 - 50°C for 3 h, dropwise add the same amount of sodium carbonate solution. After reacting for 6 h, filter by suction, wash, and dry to obtain the phase change microcapsules, with the mass ratio of the core material to the wall material being 1.04:1.2.

[0034] Preparation Example 3

[0035] 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.

[0036] Preparation Example 4

[0037] 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.

[0038] Preparation Example 5

[0039] 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.

[0040] Preparation Example 6

[0041] 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.

[0042] Preparation Example 7

[0043] The difference between Preparation Example 7 and Preparation Example 1 is that in Preparation Example 7, an equal amount of tetradecane is used to replace the core material.

[0044] Preparation Example 8

[0045] The difference between Preparation Example 8 and Preparation Example 1 is that in Preparation Example 8, an equal amount of paraffin is used to replace the core material.

[0046] Preparation Example 9

[0047] 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 addition amount of nano-titanium dioxide is 2.35 wt% of the mass of the wall material.

[0048] Preparation Example 10

[0049] 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 addition amount of nano-titanium dioxide is 4.68 wt% of the mass of the wall material.

[0050] Preparation Example 11

[0051] The difference between Preparation Example 11 and Preparation Example 9 is that in Preparation Example 11, the addition amount of nano-titanium dioxide is 1.15 wt% of the mass of the wall material.

[0052] Preparation Example 12

[0053] The difference between Preparation Example 12 and Preparation Example 9 is that in Preparation Example 12, the addition amount of nano-titanium dioxide is 5.91 wt% of the mass of the wall material.

[0054] Preparation Examples 13 - 16 of the heat-conducting fiber

[0055] Preparation Example 13

[0056] Preparation method of modified carbon nanotubes, comprising the following steps: After mixing concentrated nitric acid and concentrated sulfuric acid according to a volume ratio of 1:3, add 1 g of multi-walled carbon nanotubes, carry out condensation reflux at 80 °C for 3 h, cool, centrifuge, filter, and dry to obtain modified carbon nanotubes;

[0057] The preparation method of the heat-conducting fiber comprises the following steps: Heat polyvinyl alcohol and water to 90 °C for mixing, cool to room temperature and stir for 6 h to obtain a 10 wt% polyvinyl alcohol spinning solution, add modified carbon nanotubes, the addition amount of the modified carbon nanotubes is 4.98 wt% of polyvinyl alcohol, after ultrasonic dispersion evenly, carry out electrospinning to obtain the heat-conducting fiber, the spinning voltage is 15 kV, the spinning rate is 0.8 mL / h, and the receiving distance is 20 cm.

[0058] Preparation Example 14

[0059] Preparation method of modified carbon nanotubes, comprising the following steps: After mixing concentrated nitric acid and concentrated sulfuric acid according to a volume ratio of 1:3, add 1.2 g of multi-walled carbon nanotubes, carry out condensation reflux at 80 °C for 3 h, cool, centrifuge, filter, and dry to obtain modified carbon nanotubes;

[0060] The preparation method of the heat-conducting fiber comprises the following steps: Heat polyvinyl alcohol and water to 90 °C for mixing, cool to room temperature and stir for 7 h to obtain a 10 wt% polyvinyl alcohol spinning solution, add modified carbon nanotubes, the addition amount of the modified carbon nanotubes is 5.32 wt% of polyvinyl alcohol, after ultrasonic dispersion evenly, carry out electrospinning to obtain the heat-conducting fiber, the spinning voltage is 18 kV, the spinning rate is 0.9 mL / h, and the receiving distance is 20 cm.

[0061] Preparation Example 15

[0062] The difference between Preparation Example 15 and Preparation Example 13 is that in Preparation Example 15, the addition amount of the modified carbon nanotubes is 2.16 wt% of polyvinyl alcohol.

[0063] Preparation Example 16

[0064] The difference between Preparation Example 16 and Preparation Example 13 is that in Preparation Example 16, the addition amount of the modified carbon nanotubes is 9.25 wt% of polyvinyl alcohol.

[0065] Examples

[0066] In the examples of the present application, the polyethylene matrix is selected as SM800 of LG Chem, and the polyester is selected as R-8846 of Dongguan Zhongyuan New Material Technology Co., Ltd.

[0067] Example 1

[0068] A packaging film material with temperature control function, comprising an upper layer and a lower layer. The lower layer comprises the following raw materials in parts by weight: 40 kg of polyethylene matrix, 3 kg of phase change microcapsules, and 4 kg of heat-conducting fibers. The core material of the phase change microcapsules is tetradecane and paraffin, and the shell material is calcium carbonate. The upper layer comprises the following raw materials in parts by weight: 45 kg of polyester, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 1, and the heat-conducting fibers are the heat-conducting fibers prepared in Preparation Example 13.

[0069] The preparation process of the above-mentioned packaging film material with temperature control function comprises the following steps:

[0070] Preparation of the upper layer raw materials: Disperse the phase change microcapsules and the heat-conducting fibers in the polyethylene matrix, mix evenly, and then prepare the upper layer raw materials for standby.

[0071] Double-layer blow molding: Feed the upper layer raw materials and polyester separately, perform double-layer extrusion, and blow mold to form a film, thus forming a packaging film material with temperature control function.

[0072] Example 2

[0073] A packaging film material with temperature control function, comprising an upper layer and a lower layer. The lower layer comprises the following raw materials in parts by weight: 56 kg of polyethylene matrix, 5 kg of phase change microcapsules, and 8 kg of heat-conducting fibers. The core material of the phase change microcapsules is tetradecane and paraffin, and the shell material is calcium carbonate. The upper layer comprises the following raw materials in parts by weight: 58 kg of polyester, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 2, and the heat-conducting fibers are the heat-conducting fibers prepared in Preparation Example 14.

[0074] The preparation process of the above-mentioned packaging film material with temperature control function comprises the following steps:

[0075] Preparation of the upper layer raw materials: Disperse the phase change microcapsules and the heat-conducting fibers in the polyethylene matrix, mix evenly, and then prepare the upper layer raw materials for standby.

[0076] Double-layer blow molding: Feed the upper layer raw materials and polyester separately, perform double-layer extrusion, and blow mold to form a film, thus forming a packaging film material with temperature control function.

[0077] Example 3

[0078] 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.

[0079] Example 4

[0080] 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.

[0081] Example 5

[0082] Example 5 is different from Example 1 in that in Example 5, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 5.

[0083] Example 6

[0084] Example 6 is different from Example 1 in that in Example 6, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 6.

[0085] Example 7

[0086] Example 7 is different from Example 1 in that in Example 7, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 7.

[0087] Example 8

[0088] Example 8 is different from Example 1 in that in Example 8, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 8.

[0089] Example 9

[0090] Example 9 is different from Example 1 in that in Example 9, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 9.

[0091] Example 10

[0092] Example 10 is different from Example 1 in that in Example 10, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 10.

[0093] Example 11

[0094] Example 11 is different from Example 1 in that in Example 11, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 11.

[0095] Example 12

[0096] Example 12 is different from Example 1 in that in Example 12, the phase change microcapsules are the phase change microcapsules prepared in Preparation Example 12.

[0097] Example 13

[0098] Example 13 is different from Example 1 in that in Example 13, the heat-conducting fibers are the heat-conducting fibers prepared in Preparation Example 15.

[0099] Example 14

[0100] Example 14 is different from Example 1 in that in Example 14, the heat-conducting fibers are the heat-conducting fibers prepared in Preparation Example 16.

[0101] Comparative Example

[0102] Comparative Example 1

[0103] The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, phase change microcapsules were not added to the lower layer.

[0104] Comparative Example 2

[0105] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, the addition amount of phase change microcapsules was 8 kg.

[0106] Comparative Example 3

[0107] The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, heat conductive fibers were not added to the lower layer.

[0108] Comparative Example 4

[0109] The difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, the addition amount of heat conductive fibers was 12 kg.

[0110] Comparative Example 5

[0111] The difference between Comparative Example 5 and Example 1 is that in Comparative Example 5, neither phase change microcapsules nor heat conductive fibers were added.

[0112] Test Method

[0113] Packaging films were prepared according to the raw materials and preparation processes of Examples 1-14 and Comparative Examples 1-5. 200 g of chicken was hermetically wrapped with the packaging film, and the wrapped chicken and film were taken out after being frozen at -18°C for 24 h, placed in a constant temperature oven at 35°C, and an infrared thermal imager was used to record the initial temperature of the chicken and the temperature of the chicken after 5 h. The difference between the temperature after placement and the initial temperature was calculated, and the results are shown in Table 1.

[0114] Table 1 Temperature control performance of packaging films

[0115]

[0116]

[0117] According to Examples 1-2, Comparative Example 5 and Table 1, it can be seen that the packaging film materials prepared in Examples 1-2 have good heat insulation and heat preservation effects. In Examples 1-2, phase change microcapsules and heat-conducting fibers are added to the lower layer. Calcium carbonate is used as the wall material of the phase change microcapsules 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 a phase change, thereby regulating the temperature of the lower layer and the interior of the film material, reducing its temperature change. The heat-conducting fibers can effectively improve the heat conduction efficiency of the lower layer, and can conduct heat to the surrounding areas when the film material is locally heated, prompting more phase change microcapsules to participate in temperature regulation, reducing the situation of local regulation overload, and thus improving the temperature control effect of the film material, which is beneficial to maintaining the stability of the temperature inside the film material.

[0118] Compared with Examples 1-2, the temperature difference in Examples 3-4 is increased. When preparing the phase change microcapsules used in Examples 3-4, the molar ratio of tetradecane to paraffin is changed. In Example 7, only tetradecane is used as the core material, and in Example 8, only paraffin is used as the core material. This shows that there is a synergistic effect between tetradecane and paraffin. When tetradecane and paraffin are mixed according to the mass ratio and used as the core material, their phase change temperature control effect is better than that of using tetradecane or paraffin alone. The mixture of tetradecane and paraffin has a higher heat storage potential and can effectively improve the temperature control effect of the phase change microcapsules.

[0119] Compared with Examples 1-2, the temperature difference in Examples 5-6 is increased. When preparing the phase change microcapsules used in Examples 5-6, the mass ratio of the core material to the wall material is changed. This shows 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 is likely to result in too little wall material, incomplete coating of the core material or poor coating morphology. A decrease in the mass ratio is likely to result in excessive deposition of calcium carbonate, resulting in uneven morphology or agglomeration of the phase change microcapsules, reducing the response rate of the phase change microcapsules and its temperature control ability.

[0120] Compared with Examples 1-2, the temperature difference in Examples 9-10 is decreased. In Examples 9-10, nano-titanium dioxide is added to the sodium carbonate solution. This 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, improve the morphological uniformity of the phase change microcapsules, thereby effectively increasing the phase change enthalpy and coating rate of the phase change microcapsules, and further improving the temperature regulation function of the phase change microcapsules.

[0121] Compared with Examples 9-10, the temperature difference in Examples 11-12 is increased. In Examples 11-12, the addition amount of nano-titanium dioxide is changed. When the addition amount of nano-titanium dioxide is reduced, the improvement effect on the morphology of the phase change microcapsules decreases, the phase change enthalpy and coating rate of the phase change microcapsules are reduced. When the addition amount of nano-titanium dioxide is increased, the deposited wall material morphology of the phase change microcapsules is easily damaged, resulting in bonding, breakage, etc. of the phase change microcapsules, weakening the temperature control effect of the phase change microcapsules.

[0122] Compared with Examples 1-2, the temperature difference in Examples 13-14 is increased. When preparing the heat-conducting fibers used in Examples 13-14, the addition amount of modified carbon nanotubes in the polyvinyl alcohol spinning solution is changed. Modified carbon nanotubes can effectively improve the heat-conducting performance and mechanical properties of the heat-conducting fibers. When the addition amount is too small, the heat-conducting effect of the heat-conducting fibers is easily reduced. When the addition amount is too large, the modified carbon nanotubes are prone to agglomeration and uneven dispersion in the polyvinyl alcohol spinning solution, affecting the electrospinning effect, and thus reducing the performance of the heat-conducting fibers.

[0123] Compared with Examples 1-2, the temperature difference in Comparative Examples 1-2 is increased. In Comparative Example 1, no phase change microcapsules are added. In Comparative Example 2, the addition amount of phase change microcapsules is increased. It shows that the addition amount of phase change microcapsules has an impact on the temperature control effect of the film material. In Comparative Example 1, without adding phase change microcapsules, when the temperature of the film material in Comparative Example 1 changes, it is impossible to absorb or release heat through phase change to adjust the temperature. In Comparative Example 2, when the addition amount of phase change microcapsules is increased, the distribution of the phase change microcapsules is prone to be uneven, reducing the mechanical properties of the film material, and at the same time affecting the heat transfer and response rate of the phase change microcapsules, thus reducing the temperature control effect of the film material.

[0124] Compared with Examples 1-2, the temperature difference in Comparative Examples 3-4 is increased. In Comparative Example 3, no heat-conducting fibers are added. In Comparative Example 4, the addition amount of heat-conducting fibers is increased. It shows that the addition amount of heat-conducting fibers has an impact on the temperature control effect of the film material. In Comparative Example 3, without adding heat-conducting fibers, when the temperature of the film material in Comparative Example 3 changes, it is not easy to quickly conduct the heat of the heated part outward, thus weakening the effect of the phase change microcapsules. In Comparative Example 4, when the addition amount of heat-conducting fibers is increased, the distribution of the heat-conducting fibers is prone to be uneven, weakening the heat-conducting effect of the lower layer of the film material, thus reducing the temperature control effect of the film material.

[0125] This specific embodiment is only an interpretation of the present application, and it does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present application, it is 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; upper layer The invention comprises the following raw materials in parts by weight: 45-58 parts of polyester; the preparation method of the phase change microcapsule comprises the following steps: tetradecane and paraffin are mixed to obtain a core material mixed solution; a surfactant, the core material mixed solution and water are mixed, and then stirred and emulsified at 45-50°C for 30-40 minutes to obtain a uniform oil phase solution; a calcium chloride solution is dripped into the uniform oil phase solution, and after emulsification at 45-50°C for 3 hours, a sodium carbonate solution is dripped, and after reaction for 6 hours, the phase change microcapsule is obtained by suction filtration, washing and drying; the preparation method of the thermal conductive fiber comprises the following steps: polyvinyl alcohol and water are heated to 90°C and mixed, cooled to room temperature and stirred for 6-7 hours to obtain a polyvinyl alcohol spinning solution, and modified carbon nanotubes are added, ultrasonically dispersed uniformly, and then electrostatic spinning is performed to obtain a thermal conductive fiber.

2. 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).

3. 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).

4. The packaging film material with temperature control function according to claim 1, 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.

5. The packaging film material with temperature control function according to claim 1, characterized in that: The added amount of the modified carbon nanotubes is 4.98-5.32 wt % of the polyvinyl alcohol.

6. The process for preparing the packaging film material with temperature control function according to any one of claims 1 to 5, 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.

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