Shielding ton bag lining bag and preparation method thereof

Abstract

The invention relates to the technical field of ton bag lining materials, and particularly discloses a shielding ton bag lining bag and a preparation method thereof. The shielding ton bag lining bag is prepared by processing a multi-layer composite film with the structure of PET / light-shading, air-permeable and moisture-permeable layer / PA / PE, and the light-shading, air-permeable and moisture-permeable layer is prepared from the following raw materials in parts by weight: 40-75 parts of a resin material; 20 to 40 parts of heavy calcium carbonate; 5-10 parts of a color master batch; 2-5 parts of a dispersant; 0.2 to 0.4 part of an antioxidant; 4 to 6 parts of polyimide nanofiber; 1-3 parts of porous diatomite; the preparation method comprises the following steps: uniformly mixing the resin material, the ground calcium carbonate, the color master batch, the dispersing agent, the antioxidant, the polyimide nanofiber and the porous diatomite, and extruding and granulating to obtain a shading, air-permeable and moisture-permeable layer material; performing four-layer co-extrusion blow molding on the shading, air-permeable and moisture-permeable layer material, PET, PA and PE to obtain a multi-layer composite film, and performing bag processing to obtain the multi-layer composite film. The lining bag of the shielding ton bag can exert excellent and stable air permeability and moisture permeability under the influence of a temperature change environment.

Description

Technical Field

[0001] The present application relates to the technical field of ton bag lining materials, and more specifically, to a shielding ton bag lining bag and a preparation method thereof. Background Art

[0002] Ton bags are a kind of flexible transport packaging container, which has the advantages of moisture-proof, dust-proof, radiation-resistant, firm and safe, and has sufficient structural strength. As container bags are easy to load and unload, and handling, the loading and unloading efficiency is significantly improved, and they have developed rapidly in recent years. Ton bags are usually equipped with liner bags, which can make the ton bags have better load-bearing capacity, thereby ensuring the safety of goods during transportation or stacking, and protecting the goods from pollution and damage from the external environment, such as dust, moisture, and static electricity.

[0003] The structure of the inner liner of a ton bag is usually made of multi-layer co-extruded materials. Common materials for the inner liner of a ton bag include multi-layer composite materials such as PET / Al / PA / PE, PA / Al / PE and PET / Al / PE. Among them, the aluminum foil layer has excellent barrier properties, good light-shielding effect, and a moisture and air permeability effect of up to 0.05 or less. These materials combine the advantages of different materials through a composite process, and are soft to the touch and low in cost, making the inner liner bag widely applicable. When the inner liner of a ton bag is used in certain fresh foods, it not only requires a good light-shielding effect, but also a good moisture and air permeability effect to help the moisture inside the goods dissipate and reduce the risk of the goods getting damp and moldy. Especially for goods that are susceptible to moisture and mold, such as agricultural products and food, good air permeability can extend their shelf life and maintain the quality of the goods. Therefore, the Al in the multi-layer composite material is usually replaced with a black breathable and moisture-permeable material, which not only has a good light-shielding effect, but also can improve the air and moisture permeability of the inner liner of the ton bag, thereby meeting the use of the above-mentioned fresh foods.

[0004] With respect to the above-mentioned related technologies, the inventors believe that the black breathable and moisture-permeable material used above is easily affected by environmental factors during the application process, especially when the external ambient temperature changes greatly, it will cause great damage to the structure of the black breathable and moisture-permeable material, thereby affecting the stable performance of its breathability and moisture-permeability.

[0005] Therefore, it is urgent to propose a solution to solve the above technical problems. Summary of the invention

[0006] In order to enable the air and moisture permeability of a ton bag liner bag to be more stably exerted under the influence of a temperature change environment, the present application provides a shielding ton bag liner bag and a preparation method thereof.

[0007] In the first aspect, the present application provides a shielded ton bag liner bag, which adopts the following technical solution: A shielding ton bag liner bag is made by processing a multi-layer composite film with a structure of PET / light-shielding, breathable and moisture-permeable layer / PA / PE, and the light-shielding, breathable and moisture-permeable layer is made of raw materials containing the following parts by weight: Resin material 40-75 parts; Heavy calcium carbonate 20-40 parts; Masterbatch 5-10 parts; Dispersant 2-5 parts; Antioxidant 0.2-0.4 parts; 4-6 parts of polyimide nanofibers; 1-3 parts of porous diatomaceous earth.

[0008] By adopting the above technical scheme, in the bag structure of the shielding ton bag liner bag, PET is the outermost layer, providing good rigidity, transparency and barrier properties; the light-shielding, breathable and moisture-permeable layer can play a good light-shielding effect and bring excellent air permeability and moisture permeability; PA is to enhance the strength, puncture resistance and chemical stability of the multi-layer composite film; PE, as the innermost layer, can provide good heat sealing and flexibility; therefore, the shielding ton bag liner bag made of the multi-layer composite film of the above structure can meet the use needs of fresh food and can bring relatively excellent application effects.

[0009] At the same time, in the above-mentioned light-shielding, breathable and moisture-permeable layer, among its preparation raw materials, heavy calcium carbonate not only serves as a filler, but also undertakes the important task of "pore making". During the preparation process of the light-shielding, breathable and moisture-permeable layer, the calcium carbonate particles are separated at the junction with the plastic film matrix to form uniform micropores. These micropores are the key to the light-shielding, breathable and moisture-permeable layer to achieve the breathable and moisture-permeable functions; and the masterbatch can bring a relatively excellent light-shielding effect; the matrix of the light-shielding, breathable and moisture-permeable layer is formed mainly through the mutual cooperation between the resin material, heavy calcium carbonate and the masterbatch. In order to further make the air permeability and moisture permeability of the ton bag liner bag more stable under the influence of temperature changes, polyimide nanofibers and porous diatomaceous earth are matched, and the nano surface effect, fiber entanglement and porous diatomaceous earth's own pore structure of polyimide nanofibers are utilized to form mutual cross-linking and interlacing, thereby forming a dot network structure in the light-shielding, air-permeable and moisture-permeable layer. Based on the excellent temperature resistance of polyimide nanofibers and porous diatomaceous earth, the microporous structure of the light-shielding, air-permeable and moisture-permeable layer is fixed and protected. In this way, when the external environment temperature changes with a large span, the air permeability and moisture permeability of the shielding ton bag liner bag can still maintain better stability, and the overall application effect can be significantly improved.

[0010] Preferably, the weight ratio of the polyimide nanofibers to the porous diatomaceous earth is 2:1.

[0011] By adopting the above technical scheme, when the polyimide nanofibers and porous diatomaceous earth in the above weight ratio are used in combination, the composite effect between them is relatively excellent, and the formed dot network structure can bring better protection effect to the microporous structure of the light-shielding, breathable and moisture-permeable layer during temperature changes, thereby keeping the air permeability and moisture permeability of the shielding ton bag liner bag relatively stable.

[0012] Preferably, the diameter of the polyimide nanofiber is 150-250 nm; the pore size of the porous diatomaceous earth is 1-2 μm, and the particle size is 10-15 μm.

[0013] By adopting the above technical scheme, when the polyimide nanofibers and porous diatomaceous earth of the above specifications are used in combination, the composite effect between them is relatively excellent, and the formed dot network structure is distributed relatively evenly and densely in the light-shielding, breathable and moisture-permeable layer, and can effectively protect the microporous structure of the light-shielding, breathable and moisture-permeable layer when affected by temperature changes, avoiding major damage to the structure of the light-shielding, breathable and moisture-permeable layer, so that the ton bag liner bag can exert a relatively stable breathable and moisture-permeable effect during the application process.

[0014] Preferably, the raw materials of the light-shielding, breathable and moisture-permeable layer further contain 3-7 parts by weight of a functional additive, the functional additive is composed of polytetrafluoroethylene and nano thermal conductive filler, and the weight ratio of the polytetrafluoroethylene to the nano thermal conductive filler is 1:(4-8).

[0015] By adopting the above technical solution, polytetrafluoroethylene can remain stable within an extreme temperature range and has extremely strong chemical inertness and strength. In the light-shielding, breathable and moisture-permeable layer, it can be combined with a dot-net structure formed by polyimide nanofibers and porous diatomaceous earth, and a membrane structure can be introduced for reinforcement, thereby improving the protective effect of the microporous structure in the light-shielding, breathable and moisture-permeable layer; the nano effect of the nano thermal conductive filler and the polyimide nanofiber enables the two to be adhered and combined, and form a heat conduction path in the light-shielding, breathable and moisture-permeable layer, thereby effectively avoiding the internal generation of heat in the light-shielding, breathable and moisture-permeable layer. The drastic thermal changes can significantly reduce the damage of the microporous structure in the light-shielding, breathable and moisture-permeable layer when affected by temperature changes. When polytetrafluoroethylene and nano-thermal conductive fillers are used as functional additives, the two are compounded with each other, and the dot-net structure formed by polyimide nanofibers and porous diatomaceous earth can further deepen the cooperation, which brings excellent thermal regulation and protection effects when the external environment temperature changes with a large span, thereby enabling the light-shielding, breathable and moisture-permeable layer to exert better air permeability and moisture permeability, and finally the application stability of the ton bag liner is significantly improved.

[0016] Preferably, the weight ratio of the polytetrafluoroethylene to the nano thermal conductive filler is 1:6.

[0017] By adopting the above technical scheme, when the polytetrafluoroethylene and nano-thermal conductive filler in the above weight ratio are used in combination, the composite effect between them is relatively excellent. It can effectively play the role of membrane reinforcement and heat regulation in the dot network structure formed by polyimide nanofibers and porous diatomaceous earth, and form better compatibility. When the external ambient temperature undergoes a large temperature change, it can effectively protect the microporous structure in the light-shielding, breathable and moisture-permeable layer, thereby making the corresponding improvement effect brought by the functional additives perform better.

[0018] Preferably, the nano thermal conductive filler is composed of boron nitride and silicon carbide in a weight ratio of (2-5):1.

[0019] By adopting the above technical scheme, boron nitride and silicon carbide have excellent thermal stability, high thermal conductivity, high insulation and good mechanical strength. The combined use of the two can not only combine with polyimide nanofibers to exert excellent thermal conductivity, but also improve the structural dimensional stability of the light-shielding, breathable and moisture-permeable layer. After the application of functional additives, the stability of the light-shielding, breathable and moisture-permeable layer under the influence of temperature changes is better.

[0020] Preferably, the particle size of the nano thermal conductive filler is 50-100 nm.

[0021] By adopting the above technical solution, the nano thermal conductive filler with the above particle size has better compatibility with the polyimide nanofibers when used, and the formed thermal conductive path can fully act on the dot network structure formed by the polyimide nanofibers and porous diatomaceous earth, and is well matched with the membrane strengthening effect brought by polytetrafluoroethylene, so that the corresponding effect brought by the application of the functional additive is better.

[0022] Preferably, the dispersant is one or a combination of several of stearamide, hexenyl bis stearamide, stearic acid monoglyceride, tristearic acid glyceride, microcrystalline wax, barium stearate, zinc stearate, calcium stearate, ethylene-acrylic acid copolymer and ethylene-vinyl acetate copolymer.

[0023] By adopting the above technical scheme, the dispersant can ensure that the heavy calcium carbonate is evenly dispersed in the resin material to avoid agglomeration, thereby reducing the appearance of macropores and improving the air permeability and moisture permeability of the light-shielding, breathable and moisture-permeable layer; at the same time, the dispersant can also improve the processing performance of the light-shielding, breathable and moisture-permeable layer, so that the raw materials used can play an excellent role, thereby obtaining a light-shielding, breathable and moisture-permeable layer of excellent quality; and the above-mentioned types of dispersants are all suitable for the preparation of light-shielding, breathable and moisture-permeable layers, and can play the above-mentioned excellent roles.

[0024] Preferably, the antioxidant is one or a combination of di-tert-butylphenol, triphenyl phosphate, o-phenylenediamine and catechol.

[0025] By adopting the above technical scheme, antioxidants can effectively inhibit or reduce the thermal oxidation reaction rate of resin macromolecules, delay the thermal and oxygen degradation process of the resin, thereby significantly improving the heat resistance of the resin, which helps to maintain the stability and performance of the light-shielding, breathable and moisture-permeable layer in a high temperature environment; and the above types of antioxidants are all suitable for the preparation of light-shielding, breathable and moisture-permeable layers, and can exert the above-mentioned excellent effects.

[0026] In the second aspect, the present application provides a method for preparing a shielded ton bag liner bag, using the following technical solution: A method for preparing a shielded ton bag liner bag comprises the following steps: (1) preparing raw materials including resin material, heavy calcium carbonate, masterbatch, dispersant, antioxidant, polyimide nanofiber and porous diatomaceous earth according to a ratio; (2) mixing the resin material, heavy calcium carbonate, masterbatch, dispersant, antioxidant, polyimide nanofiber and porous diatomaceous earth in step (1) uniformly, and extruding and granulating to obtain a light-shielding, air-permeable and moisture-permeable layer material; (3) The light-shielding, breathable and moisture-permeable layer material obtained in step (2) is subjected to four-layer co-extrusion blow molding with PET, PA and PE to obtain a multilayer composite film with a structure of PET / light-shielding, breathable and moisture-permeable layer / PA / PE, and then subjected to bag making processing to obtain a shielding ton bag liner bag.

[0027] By adopting the above technical scheme, the above preparation method is simple to operate. In the preparation process of the light-shielding, breathable and moisture-permeable layer material, the raw materials are processed in one pot, which can ensure that the interaction between the raw materials can be excellent. The overall performance is better applicability, and finally a shielding ton bag liner bag with excellent and stable quality can be obtained, and the whole is also suitable for large-scale industrial production.

[0028] In summary, this application has the following beneficial effects: 1. The present application combines polyimide nanofibers and porous diatomite, utilizes the nano surface effect of polyimide nanofibers, fiber entanglement and the porous structure of porous diatomite itself, forms cross-linking and interlacing, and then forms a dot network structure in the light-shielding, breathable and moisture-permeable layer. When the external environment temperature changes over a large span, the microporous structure of the light-shielding, breathable and moisture-permeable layer can be fixed and protected, so that the final shielding ton bag liner can still show stable and better air permeability and moisture permeability. 2. When polytetrafluoroethylene and nano-thermal conductive fillers are used as functional additives in this application, the combination of the two and the dot-net structure formed by polyimide nanofibers and porous diatomaceous earth can further deepen the coordination and bring excellent thermal regulation and protection effects, thereby significantly improving the application stability of the shielding ton bag liner bag when it is affected by a large span of temperature changes. DETAILED DESCRIPTION

[0029] The present application is further described in detail below with reference to examples and comparative examples.

[0030] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of the present application are commercially available: Metallocene linear polyolefin resin was purchased from MVLDPE (metallocene) Japan Prime SP0540; Low-density polyethylene resin was purchased from Qatar Petrochemical LA0710; Heavy calcium carbonate was purchased from Nanzhao County Wandu Micro Powder Technology Co., Ltd., with a specification of 325 mesh; The color masterbatch was purchased from the black masterbatch of Jinan Dahua Plastic Processing Plant. Example

[0031] Example 1 A shielding ton bag liner is made by processing a multilayer composite film having a structure of PET / light-shielding breathable and moisture-permeable layer / PA / PE. The raw materials used to prepare the light-shielding breathable and moisture-permeable layer and their corresponding weights are shown in Table 1. The shielding ton bag liner is prepared by the following steps: (1) preparing raw materials including resin material, heavy calcium carbonate, masterbatch, dispersant, antioxidant, polyimide nanofiber and porous diatomaceous earth according to a ratio; (2) mixing the resin material, heavy calcium carbonate, masterbatch, dispersant, antioxidant, polyimide nanofiber and porous diatomaceous earth in step (1) uniformly, and extruding and granulating to obtain a light-shielding, air-permeable and moisture-permeable layer material; (3) The light-shielding, breathable and moisture-permeable layer material obtained in step (2) is subjected to four-layer co-extrusion blow molding with PET, PA and PE to obtain a multilayer composite film with a structure of PET / light-shielding, breathable and moisture-permeable layer / PA / PE, and then subjected to bag making processing to obtain a shielding ton bag liner bag.

[0032] Note: In the above operation, the resin material is composed of metallocene linear polyolefin resin and low-density polyethylene resin in a weight ratio of 3:2; the diameter of the polyimide nanofiber is 200nm; the pore size of the porous diatomaceous earth is 1.5μm, and the particle size is 12.5μm; the dispersant is stearamide; and the antioxidant is di-tert-butylphenol.

[0033] Example 2-3 A shielding ton bag liner bag, which is different from Example 1 in that the raw materials used to prepare the light-shielding, breathable and moisture-permeable layer and their corresponding weights are shown in Table 1.

[0034] Table 1 Raw materials used in preparing the light-shielding, air-permeable and moisture-permeable layers in Examples 1-3 and their weight portions (kg / portion) raw material Example 1 Example 2 Example 3 Resin 57.5 40 75 Heavy calcium carbonate 60 20 40 Masterbatch 7.5 5 10 Dispersants 3.5 2 5 Antioxidants 0.3 0.2 0.4 Polyimide Nanofibers 5 4 6 Porous diatomaceous earth 2 1 3 Example 4 A shielding ton bag liner bag is different from Example 1 in that the total amount of polyimide nanofibers and porous diatomaceous earth remains unchanged, and the weight ratio of the two is adjusted to 2:1.

[0035] Example 5 A shielding ton bag liner bag, which is different from Example 1 in that the diameter of the polyimide nanofiber is 150 nm; the pore size of the porous diatomaceous earth is 1 μm, and the particle size is 10 μm.

[0036] Example 6 A shielding ton bag liner bag, which is different from Example 1 in that the diameter of the polyimide nanofiber is 250 nm; the pore size of the porous diatomaceous earth is 2 μm, and the particle size is 15 μm.

[0037] Example 7 A shielding ton bag liner bag, which is different from Example 1 in that 5 parts by weight of a functional additive are also added to the raw materials of the light-shielding, breathable and moisture-permeable layer, the functional additive is composed of polytetrafluoroethylene and nano thermal conductive filler in a weight ratio of 1:6, and the functional additive is added together with other raw materials in the operation of step (2); wherein the nano thermal conductive filler is composed of boron nitride and silicon carbide in a weight ratio of 3.5:1, and the particle size of the nano thermal conductive filler is 75nm.

[0038] Example 8 A shielding ton bag liner bag, which is different from Example 7 in that the weight portion of the functional additive added is 3 parts.

[0039] Example 9 A shielding ton bag liner bag, which is different from Example 7 in that the weight parts of the functional additive added is 7 parts.

[0040] Example 10 A shielding ton bag liner bag, which is different from Example 7 in that the functional additive is composed of polytetrafluoroethylene and nano thermal conductive filler in a weight ratio of 1:4.

[0041] Embodiment 11 A shielding ton bag liner bag, which is different from Example 7 in that the functional additive is composed of polytetrafluoroethylene and nano thermal conductive filler in a weight ratio of 1:8.

[0042] Example 12 A shielding ton bag liner bag, which is different from Example 7 in that the nano thermal conductive filler is composed of boron nitride and silicon carbide in a weight ratio of 2:1.

[0043] Embodiment 13 A shielding ton bag liner bag, which is different from Example 7 in that the nano thermal conductive filler is composed of boron nitride and silicon carbide in a weight ratio of 5:1.

[0044] Embodiment 14 A shielding ton bag liner bag, which is different from Example 7 in that the particle size of the nano thermal conductive filler is 50 nm.

[0045] Embodiment 15 A shielding ton bag liner bag, which is different from Example 7 in that the particle size of the nano thermal conductive filler is 100 nm.

[0046] Example 16 A shielding ton bag liner bag, which is different from Example 7 in that polytetrafluoroethylene is not used in the raw material of the light-shielding, breathable and moisture-permeable layer.

[0047] Embodiment 17 A shielding ton bag liner bag, which is different from Example 7 in that no nano thermal conductive filler is used in the raw materials of the light-shielding, breathable and moisture-permeable layer.

[0048] Comparative Example Comparative Example 1 A shielding ton bag liner bag, which is different from Example 1 in that polyimide nanofibers are not used in the raw materials of the light-shielding, breathable and moisture-permeable layer.

[0049] Comparative Example 2 A shielding ton bag liner bag, which is different from Example 1 in that porous diatomaceous earth is not used in the raw material of the light-shielding, breathable and moisture-permeable layer.

[0050] Comparative Example 3 A shielding ton bag liner bag is different from Example 1 in that polyimide nanofibers and porous diatomaceous earth are not used in the raw materials of the light-shielding, breathable and moisture-permeable layer.

[0051] Comparative Example 4 A shielding ton bag liner bag, which is different from Example 7 in that polyimide nanofibers and porous diatomaceous earth are not used in the raw materials of the light-shielding, breathable and moisture-permeable layer.

[0052] Performance test samples: The shielding ton bag liner bag obtained in Example 1-17 was used as test sample 1-17, and the shielding ton bag liner bag obtained in Comparative Example 1-4 was used as control sample 1-4; wherein, the size of the shielding ton bag liner bag is 1.2m×1.2m×1.5m, and the thickness of each layer of its structure PET / light-shielding breathable and moisture-permeable layer / PA / PE is 12μm, 50μm, 25μm, and 100μm, respectively.

[0053] Test method: For the inner liner of shielded ton bags, the air permeability (g / m 2 ·24h) and moisture permeability (g / m 2 ·24h) test to obtain the initial values ​​A1 and B1; Then the shielded ton bag liner is placed in a high and low temperature alternating test chamber, with the initial temperature of 25°C, first heated to 80°C at 3°C / min, then cooled to -10°C at 1.5°C / min, and then heated to 25°C at 2°C / min, which is recorded as one cycle. After 20 cycles, the air permeability (g / m 2 ·24h) and moisture permeability (g / m 2 ·24h) test to obtain the final values ​​A2 and B2; Finally, the air permeability reduction rate and moisture permeability reduction rate are carried out, among which, the air permeability reduction rate (%) = (A1-A2) / A1, the moisture permeability reduction rate (%) = (B1-B2) / B1; and the greater the air permeability reduction rate and the moisture permeability reduction rate, the worse the stability of the shielding ton bag liner bag under the influence of temperature changes.

[0054] According to the above method, after completing the test samples 1-17 and the control samples 1-4 in turn, the experimental results are recorded in Table 2 accordingly.

[0055] Table 2 Test results of test samples 1-17 and control samples 1-4 Combining Examples 1-3 and Comparative Examples 1-3 and Table 2, it can be seen that in the light-shielding, breathable and moisture-permeable layer, the combination of polyimide nanofibers and porous diatomite can significantly improve the breathability and moisture-permeability stability in a temperature-changing environment. The above experimental tests show that the air permeability reduction rate and the moisture permeability reduction rate are significantly reduced; and if only any one of polyimide nanofibers and porous diatomite is used, although it can improve the breathability and moisture-permeability stability compared to the case where polyimide nanofibers and porous diatomite are not used, the improvement effect is limited, and the sum of the improvement effects brought by using each alone is far less than the excellent combination of the two. It can be seen that the combination of polyimide nanofibers and porous diatomite can bring a significant improvement effect of 1+1>2. Combining Example 4 and Table 2, it can be seen that when the external environment temperature changes over a large span, the weight ratio of polyimide nanofibers and porous diatomite is 2:1, which can keep the air permeability and moisture permeability of the shielding ton bag liner bag relatively stable and excellent.

[0056] It can be seen from Example 1 and Example 7-11 and Table 2 that when the present application uses polytetrafluoroethylene and nano-thermal conductive fillers as functional additives, the application stability of the shielded ton bag liner bag can be significantly improved when it is affected by a large span of temperature changes. The air permeability reduction rate and moisture permeability reduction rate obtained by the above test are significantly reduced. It can be seen from Example 12-15 and Table 2 that the nano-thermal conductive filler is composed of boron nitride and silicon carbide in a weight ratio of (2-5): 1, and the particle size of the nano-thermal conductive filler is 50-100nm, which can make the functional additive play an excellent and stable effect. It can be seen from Example 17-18 and Table 2 that if only polytetrafluoroethylene or nano-thermal conductive fillers are used alone, the effect of improving the air permeability and moisture permeability stability is far less than the excellent effect brought by the combination of the two. Combined with Comparative Examples 1 and 4 and Table 2, it can be seen that without the use of polyimide nanofibers and porous diatomaceous earth, the corresponding improvement effect brought by the functional additives will be greatly discounted, indicating that the combination of polytetrafluoroethylene and nano-thermal conductive fillers in the functional additives is inseparable from the combination of polyimide nanofibers and porous diatomaceous earth, which is a necessary condition to ensure that the stability of the light-shielding, breathable and moisture-permeable layer is significantly improved under temperature changes, thereby obtaining a shielding ton bag liner with better application quality.

[0057] 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, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A shielded bulk bag liner bag, characterized in that: It is made of a multi-layer composite film with a structure of PET / light-shielding, breathable and moisture-permeable layer / PA / PE, and the light-shielding, breathable and moisture-permeable layer is made of raw materials containing the following parts by weight: Resin material 40-75 parts; Heavy calcium carbonate 20-40 parts; Masterbatch 5-10 parts; Dispersant 2-5 parts; Antioxidant 0.2-0.4 parts; 4-6 parts of polyimide nanofibers; 1-3 parts of porous diatomaceous earth.

2. The shielding ton bag liner bag according to claim 1 is characterized by: The weight ratio of the polyimide nanofiber to the porous diatomaceous earth is 2:

1.

3. The shielding ton bag liner bag according to claim 1 is characterized by: The diameter of the polyimide nanofiber is 150-250nm; the pore size of the porous diatomaceous earth is 1-2μm, and the particle size is 10-15μm.

4. The shielding ton bag liner bag according to claim 1 is characterized in that: The raw materials of the light-shielding, breathable and moisture-permeable layer further contain 3-7 parts by weight of a functional additive, wherein the functional additive is composed of polytetrafluoroethylene and nano thermal conductive filler, and the weight ratio of the polytetrafluoroethylene to the nano thermal conductive filler is 1:(4-8).

5. The shielding ton bag liner bag according to claim 4 is characterized in that: The weight ratio of the polytetrafluoroethylene to the nano thermal conductive filler is 1:

6.

6. The shielding ton bag liner bag according to claim 4 is characterized in that: The nano thermal conductive filler is composed of boron nitride and silicon carbide in a weight ratio of (2-5):

1.

7. The shielding ton bag liner bag according to claim 4 is characterized in that: The particle size of the nano thermal conductive filler is 50-100 nm.

8. The shielding ton bag liner bag according to claim 1 is characterized by: The dispersant is one or a combination of stearamide, hexenyl bis stearamide, stearic acid monoglyceride, tristearic acid glyceride, microcrystalline wax, barium stearate, zinc stearate, calcium stearate, ethylene-acrylic acid copolymer and ethylene-vinyl acetate copolymer.

9. The shielding ton bag liner bag according to claim 1, characterized in that: The antioxidant is one or a combination of di-tert-butylphenol, triphenyl phosphate, o-phenylenediamine and catechol.

10. The method for preparing the shielded ton bag liner bag according to claim 1, characterized in that: The following steps are involved: (1) preparing raw materials including resin material, heavy calcium carbonate, masterbatch, dispersant, antioxidant, polyimide nanofiber and porous diatomaceous earth according to the proportion; (2) the resin material, heavy calcium carbonate, masterbatch, dispersant, antioxidant, polyimide nanofiber and porous diatomaceous earth in step (1) are uniformly mixed and then extruded and granulated to obtain a light-shielding, air-permeable and moisture-permeable layer material; (3) The light-shielding, breathable and moisture-permeable layer material obtained in step (2) is subjected to four-layer co-extrusion blow molding with PET, PA and PE to obtain a multilayer composite film with a structure of PET / light-shielding, breathable and moisture-permeable layer / PA / PE, and then subjected to bag making processing to obtain a shielding ton bag liner bag.

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