A novel film for preparing a gas column bag and a method for preparing the same

Abstract

This invention provides a novel film for preparing air column bags and its preparation method. The film has an A / B / A three-layer co-extrusion structure with a total thickness of 80-120 μm. By weight, the A layer raw materials include: 45-55 parts linear low-density polyethylene, 8-12 parts EPDM rubber, 12-18 parts reactive pre-crosslinked hybrid toughening particles, 5-8 parts ionic liquid intercalated modified hydrophobic hydrotalcite, 3-5 parts maleic anhydride-grafted polyethylene, and maleic anhydride-grafted polyglycerol-10-month... The air column bag of this invention comprises 2-4 parts of cinnamic acid ester, 6-10 parts of ethylene-octene copolymer, 0.3-0.6 parts of antioxidant compound, 0.5-1.0 parts of processing aid, and 0.1-0.3 parts of dicyandiamide latent catalyst. By weight, the B layer raw materials include: 60-70 parts of ethylene-vinyl alcohol copolymer, 15-20 parts of polyamide, 8-12 parts of ionic liquid intercalated modified hydrophobic hydrotalcite, 5-8 parts of maleic anhydride grafted ethylene-vinyl alcohol copolymer, and 0.2-0.4 parts of antioxidant. The air column bag of this invention is made of an A / B / A three-layer co-extruded film, possessing excellent mechanical properties, puncture resistance, barrier properties, weather resistance, and interlayer bonding properties, exhibiting outstanding overall performance.

Description

Technical Field

[0001] This invention relates to the field of packaging cushioning materials technology, specifically to a novel film for preparing air column bags and its preparation method. Background Technology

[0002] Air column bags, as a new type of cushioning packaging material, are widely used in the packaging and protection of electronic appliances, precision instruments, handicrafts, food, and other products due to their advantages such as lightweight, excellent cushioning performance, and convenient warehousing and transportation. They can effectively absorb impact energy during transportation and reduce product damage rates. Currently, the industry mostly uses polyethylene, polyamide, and other base materials to prepare special films for air column bags through multi-layer co-extrusion blow molding processes to meet basic requirements such as mechanical support, heat sealing, and gas barrier properties.

[0003] Existing multilayer co-extruded films for air column bags typically achieve basic mechanical properties and airtightness requirements through simple composites of different substrates. However, they still have significant limitations in practical applications. On the one hand, the interlayer bonding strength of the film is insufficient, making it prone to delamination and peeling during heat sealing and inflation, affecting the structural integrity of the air column bag. On the other hand, it is difficult to simultaneously achieve both gas barrier properties and puncture resistance. Either the barrier properties are poor, leading to easy air leakage and short pressure holding time, or the puncture resistance is insufficient, making it easy to be punctured by sharp objects during transportation, losing its cushioning and protective function, and failing to meet the long-term stable packaging and protection requirements of high-precision instruments. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a novel thin film for preparing air column bags and a method for preparing the same.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a novel film for preparing air column bags, wherein the film has an A / B / A three-layer co-extrusion structure and a total thickness of 80~120μm; By weight, the raw materials for preparing layer A include: 45-55 parts linear low-density polyethylene, 8-12 parts EPDM rubber, 12-18 parts reactive pre-crosslinked hybrid toughening particles, 5-8 parts ionic liquid intercalated modified hydrophobic hydrotalcite, 3-5 parts maleic anhydride grafted polyethylene, 2-4 parts maleic anhydride grafted polyglycerol-10 laurate, 6-10 parts ethylene-octene copolymer, 0.3-0.6 parts antioxidant compound, 0.5-1.0 parts processing aid, and 0.1-0.3 parts dicyandiamide latent catalyst; The raw materials for preparing layer B, by weight, include: 60-70 parts of ethylene-vinyl alcohol copolymer, 15-20 parts of polyamide, 8-12 parts of ionic liquid intercalated modified hydrophobic hydrotalcite, 5-8 parts of maleic anhydride grafted ethylene-vinyl alcohol copolymer, and 0.2-0.4 parts of antioxidant.

[0006] Using the above technical solutions, linear low-density polyethylene (LDPE) serves as the film-forming substrate for layer A, providing basic mechanical and heat-sealing properties. EPDM rubber enhances the elastic recovery and weather resistance of layer A. Reactive pre-crosslinked hybrid toughening particles enhance the puncture resistance and dispersion stability of layer A, while also reacting with maleic anhydride-grafted polyethylene at the interface to improve interlayer bonding. Ionic liquid intercalation-modified hydrophobic hydrotalcite improves the gas barrier properties and permeability of layers A and B, reduces the gas and water vapor permeability coefficients, and enhances the mechanical properties of layers A and B. Maleic anhydride-grafted polyethylene improves the compatibility between polar and non-polar components in layer A, acting as an interface bridge. Maleic anhydride-grafted polyglycerol-10 laurate lowers the heat-sealing temperature of layer A, improves its processing fluidity, and reduces migration. Ethylene-octene copolymer further enhances the toughness and processing properties of layer A. Flowability; antioxidant compound can inhibit the thermo-oxidative aging of layer A during processing and use; processing aids can improve the melt lubricity and demolding effect of layer A, avoiding melt cracking; dicyandiamide-based latent catalysts can catalyze the ring-opening addition reaction between the epoxy groups on the reactive pre-crosslinked hybrid toughening particles in layer A and the anhydride groups of maleic anhydride grafts, further enhancing the interfacial bonding strength of layer A; ethylene-vinyl alcohol copolymer and polyamide, as the core components of layer B, can provide excellent gas barrier properties and mechanical properties; maleic anhydride grafted ethylene-vinyl alcohol copolymer can improve the compatibility of each component in layer B and enhance the overall stability of layer B; antioxidants can inhibit the thermo-oxidative aging of layer B during processing and use; the synergistic effect of each component makes the A / B / A three-layer co-extruded film possess good mechanical properties, gas barrier properties, heat sealing properties, weather resistance, and interlayer bonding properties.

[0007] Preferably, the linear low-density polyethylene is metallocene linear low-density polyethylene with a density of 0.912~0.918 g / cm³. 3 The melt flow index is 1.0~2.0 g / 10min (190℃, 2.16 kg); the ethylene content in the EPDM rubber is 55~65 wt%; the grafting rate of the maleic anhydride-grafted polyethylene is 0.8~1.2%; the grafting rate of the maleic anhydride-grafted polyglycerol-10 laurate is 1.0~1.5%; the D of the dicyandiamide-based latent catalyst... 50 The particle size is ≤5μm, and the activation temperature is 160~180℃; the grafting rate of the maleic anhydride-grafted ethylene-vinyl alcohol copolymer is 0.5~0.8%.

[0008] Using the above technical solution, the density and melt index of metallocene linear low-density polyethylene (MDPE) give it good film-forming properties and processing stability, making it suitable as a base film-forming substrate for the A layer of a thin film, while also providing suitable heat-sealing performance and mechanical support. The specific ethylene content in EPDM rubber ensures its compatibility with MPE while maintaining its excellent elastic recovery and weather resistance. The grafting rate of maleic anhydride-grafted polyethylene ensures that its anhydride groups can fully react with the epoxy and hydroxyl groups in the system, playing an interfacial bridging role and improving the compatibility between polar and non-polar components. Maleic acid... The grafting rate of anhydride-grafted polyglycerol-10 laurate enables its chemical fixation in the A layer of the film, exerting an internal plasticizing effect to regulate the heat-sealing temperature while reducing migration. The particle size and activation temperature of the dicyandiamide-based latent catalyst allow it to be uniformly dispersed during film processing and release active amine groups at suitable processing temperatures, catalyzing the ring-opening addition reaction of epoxy groups and acid anhydride groups, thereby improving interfacial bonding strength. The grafting rate of maleic anhydride-grafted ethylene-vinyl alcohol copolymer ensures its compatibility with the components in the B layer of the film, promotes the uniform dispersion of the components in the B layer, and improves the overall stability and barrier properties of the B layer.

[0009] Preferably, the antioxidant compound in layer A is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 to 2, the processing aid is composed of zinc stearate and fluoropolymer processing aid in a mass ratio of 1 to 2:1, and the polyamide is polyamide 6; the antioxidant in layer B is one or a combination of antioxidant 1010 and antioxidant 168.

[0010] Using the above technical solution, the antioxidant compound of layer A, which is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 to 2, can exert the synergistic effect of the main and auxiliary antioxidants, inhibit the thermo-oxidative aging of layer A material during melt processing and long-term use, and maintain the mechanical properties and processing stability of layer A. The processing aid of layer A, which is composed of zinc stearate and fluoropolymer processing aid in a mass ratio of 1 to 2:1, can improve the melt processing fluidity of layer A material, achieve lubrication and demolding effect, reduce melt fracture, and improve the surface forming quality of film. Polyamide 6 can form a compatible system with ethylene-vinyl alcohol copolymer, improve the mechanical strength and molding processing stability of layer B, and help optimize the gas barrier performance of layer B. The antioxidant in layer B is one or two of antioxidant 1010 and antioxidant 168, which can be adapted to the processing temperature and component system of layer B, inhibit the thermo-oxidative aging of ethylene-vinyl alcohol copolymer and polyamide 6 in layer B during melt processing and use, and maintain the stability of barrier performance and mechanical properties of layer B.

[0011] Preferably, the raw materials for preparing the reactive pre-crosslinked hybrid toughening particles, by weight, include: 90-100 parts of EPDM rubber, 800-900 parts of anhydrous toluene, 10-15 parts of m-chloroperoxybenzoic acid, 8-12 parts of tetraethyl orthosilicate, 4-6 parts of deionized water, 0.5-0.8 parts of dibutyltin dilaurate, 0.3-0.6 parts of bis(tert-butylperoxyisopropyl)benzene, and 200-300 parts of methanol.

[0012] Using the above technical solution, EPDM rubber, as the matrix component of reactive pre-crosslinked hybrid toughening particles, provides an elastic framework for the particles, constituting the elastic matrix of the toughening particles; anhydrous toluene, as a solvent, allows EPDM rubber to be fully dissolved, forming a uniform and transparent reaction system, providing a stable environment for subsequent epoxidation modification and in-situ sol-gel reaction; m-chloroperoxybenzoic acid, as an epoxidizing agent, allows EPDM rubber to undergo epoxidation modification, introducing epoxy groups onto its molecular chain, providing active sites for subsequent interfacial reactions between the particles and compatibilizers; tetraethyl orthosilicate, as a silicon source, under the catalysis of dibutyltin dilaurate, can... In-situ hydrolysis and condensation reaction generates nano-silica, forming a core-shell hybrid system that enhances particle rigidity and dispersion stability. Dibutyltin dilaurate acts as a catalyst, accelerating the hydrolysis and condensation reaction rate of tetraethyl orthosilicate and ensuring uniform generation of nano-silica. Bis(tert-butylperoxyisopropyl)benzene acts as a crosslinking agent, enabling mild pre-crosslinking of the EPDM rubber phase and maintaining the structural stability of the particles during subsequent high-temperature melt processing. Methanol acts as a precipitant, allowing the hybrid products after the reaction to precipitate rapidly, facilitating subsequent separation, washing, and drying, ultimately yielding pure reactive pre-crosslinked hybrid toughened particles.

[0013] Preferably, the preparation method of the reactive pre-crosslinked hybrid toughening particles includes the following steps: 1) Prepare a 20-30 wt% m-chloroperoxybenzoic acid / anhydrous toluene solution by dissolving m-chloroperoxybenzoic acid in a portion of anhydrous toluene; add EPDM rubber to the remaining anhydrous toluene and stir at 300-400 r / min at 60-70℃ for 2-3 hours; add the m-chloroperoxybenzoic acid / anhydrous toluene solution dropwise at a rate of 1-2 mL / min; after the addition is complete, stir at 300-400 r / min at 70-75℃ for 3-4 hours to obtain an epoxidized EPDM rubber solution. 2) The epoxidized EPDM rubber solution was stirred at 50-60℃ and 250-350 r / min for 4-6 h. Tetraethyl orthosilicate, deionized water, and dibutyltin dilaurate were added, and the mixture was stirred at 50-60℃ and 250-350 r / min for 12-16 h to obtain an organic-inorganic hybrid system. 3) First, remove toluene from the organic-inorganic hybrid system under reduced pressure, then add bis(tert-butylperoxyisopropyl)benzene to it, transfer it to a mixer, heat it to 160~170℃, control the speed of the mixer to 80~100r / min and the filling coefficient to 0.7~0.8, and mix for 3~5min; 4) Add the material after intensive mixing in step 3) to methanol and stir at 150~200 r / min for 5~10 min. Then let it stand and settle for 1~2 h. Vacuum filter, wash the filter cake with methanol 3~4 times, place the washed solid in a vacuum drying oven and dry it at 80~90℃ and vacuum degree -0.090~-0.095MPa for 4~6 h. Crush and sieve to obtain reactive pre-crosslinked hybrid toughening particles with a particle size of 2~4 μm.

[0014] Using the above technical solution, epoxy groups are introduced into the EPDM molecular chain through the epoxidation reaction of m-chloroperoxybenzoic acid and EPDM rubber, providing active sites for subsequent interfacial reactions. Tetraethyl orthosilicate undergoes hydrolysis and condensation reaction under the catalysis of dibutyltin dilaurate, forming nano-silica between the epoxidized EPDM molecular chains, thus constructing an organic-inorganic hybrid system. Bis(tert-butylperoxyisopropyl)benzene causes mild pre-crosslinking of the EPDM phase during the mixing process, maintaining the structural stability of the hybrid system. Methanol can precipitate the hybrid products, and after washing, vacuum drying, crushing and sieving, reactive pre-crosslinked hybrid toughening particles with high purity and uniform particle size are obtained.

[0015] Preferably, the raw materials for preparing the ionic liquid intercalated modified hydrophobic hydrotalcite, by weight, include: 30-34 parts of magnesium nitrate hexahydrate, 10-14 parts of aluminum nitrate nonahydrate, 12-16 parts of sodium hydroxide, 8-10 parts of anhydrous sodium carbonate, 400-600 parts of deionized water, 15-20 parts of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1-2 parts of silane coupling agent KH-570, and 50-80 parts of anhydrous ethanol.

[0016] Using the above technical solution, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate, as magnesium and aluminum sources, can generate magnesium-aluminum hydrotalcite precursors through co-precipitation reaction; sodium hydroxide and anhydrous sodium carbonate, as alkali and carbonate donors, can adjust the pH of the reaction system, providing suitable conditions for the aging of magnesium-aluminum hydrotalcite precursors; deionized water, as the reaction medium, can dissolve the inorganic raw materials, allowing the co-precipitation and aging reactions to proceed smoothly; 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt can be inserted into the interlayer of hydrotalcite through anion exchange, expanding the interlayer spacing; silane coupling agent KH-570 can react with hydroxyl groups on the surface of hydrotalcite, improving the surface properties of hydrotalcite; anhydrous ethanol can be used as a dispersion and washing medium, promoting the grafting reaction of silane coupling agent, while removing residual impurities and ionic liquids on the surface of hydrotalcite. The synergistic effect of the raw materials realizes the preparation of hydrophobic hydrotalcite modified by ionic liquid intercalation.

[0017] Preferably, the preparation method of the ionic liquid intercalated modified hydrophobic hydrotalcite includes the following steps: (1) Under nitrogen protection, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate are added to a portion of deionized water at 60-70℃ to prepare a salt solution with a total metal salt concentration of 0.5-0.8 mol / L; sodium hydroxide and anhydrous sodium carbonate are added to a portion of deionized water at 60-70℃ to prepare an alkaline solution with a total metal salt concentration of 1.0-1.5 mol / L; the salt solution and alkaline solution are simultaneously added dropwise to the reaction vessel at a rate of 2-3 mL / min to maintain the pH of the reaction system at 9.5. The temperature was maintained at 60-70℃ for 18-24 hours. After aging, the reaction solution was centrifuged at 8000-10000 r / min for 15-20 min, the precipitate was collected, and the precipitate was washed with deionized water 3-4 times until the pH of the washing solution reached 6.8-7.2. The washed precipitate was placed in a vacuum drying oven and dried at 60-70℃ and a vacuum of -0.090 to -0.095 MPa for 12-14 hours to obtain the Mg-Al LDH precursor. (2) Add the Mg-Al LDH precursor to the remaining deionized water and disperse it for 30-40 min under ultrasonic power of 300-400 W and frequency of 20-30 kHz. Then transfer it to the reaction vessel, add 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine salt, and stir the reaction at 250-350 r / min at 70-80 °C for 24-30 h. Centrifuge the reaction solution at 8000-10000 r / min for 15-20 min, collect the precipitate, wash the precipitate with deionized water 3-4 times, place the washed precipitate in a vacuum drying oven, and dry it for 10-12 h at 70-80 °C and vacuum degree of -0.090--0.095 MPa to obtain ionic liquid intercalated modified LDH. (3) Add the ionic liquid intercalated modified LDH to anhydrous ethanol and stir at 200~300 r / min for 10~15 min. Add silane coupling agent KH-570 dropwise at a rate of 0.5~1 mL / min. After the addition is complete, stir the reaction at 150~200 r / min at 60~70℃ for 4~6 h. Centrifuge the reaction solution at 8000~10000 r / min for 15~20 min, collect the precipitate, wash the precipitate with deionized water 3~4 times, place the washed precipitate in a vacuum drying oven, and dry it at 80~90℃ and vacuum degree -0.090~-0.095 MPa for 8~10 h. After cooling to 25~30℃, grind it through a 400~450 mesh sieve to obtain ionic liquid intercalated modified hydrophobic hydrotalcite.

[0018] Using the above technical solution, step (1) involves co-precipitation, aging, centrifugation and washing, and vacuum drying of salt and alkali solutions under specific conditions to obtain a well-structured Mg-Al LDH precursor; step (2) involves using ultrasonic dispersion to uniformly disperse the Mg-Al LDH precursor, and then reacting it with 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and subsequent centrifugation and drying to achieve intercalation of the ionic liquid between LDH layers; step (3) involves dispersing the ionic liquid-intercalated modified LDH in anhydrous ethanol, reacting it with the silane coupling agent KH-570, and then centrifuging, washing, vacuum drying, grinding and sieving to reduce the water absorption of the LDH surface, ultimately obtaining the target product.

[0019] Preferably, the raw materials for preparing the maleic anhydride-grafted polyglycerol-10 laurate, by weight, include: 90-100 parts of polyglycerol-10 laurate, 5-8 parts of maleic anhydride, 0.1-0.2 parts of hydroquinone, 150-200 parts of anhydrous toluene, and 100-150 parts of methanol. The preparation method of the maleic anhydride-grafted polyglycerol-10 laurate includes the following steps: a. Add polyglycerol-10 laurate and anhydrous toluene to a reaction vessel and stir at 70-80°C at 200-300 r / min for 1-2 h to dissolve. Then add maleic anhydride and hydroquinone, heat to 90-100°C, and stir at 250-350 r / min for 6-8 h. b. After the reaction is complete, cool to 40-50℃, add methanol, stir at 250-350 r / min for 1-2 h, centrifuge the reaction solution at 8000-10000 r / min for 15-20 min, collect the precipitate, wash the precipitate with deionized water 3-4 times, and then place the washed precipitate in a vacuum drying oven and dry it at 70-80℃ and a vacuum degree of -0.090 to -0.095 MPa for 6-8 h to obtain maleic anhydride-grafted polyglycerol-10 laurate.

[0020] Using the above technical solution, in step a, anhydrous toluene can dissolve polyglycerol-10 laurate to form a homogeneous system. Stirring at 70~80℃ ensures uniform dispersion of the raw materials. At 90~100℃, maleic anhydride can undergo ring-opening esterification with the hydroxyl groups of polyglycerol-10 laurate. Hydroquinone can inhibit the occurrence of side reactions during the reaction process. In step b, adding methanol after cooling can cause the reaction product to precipitate. High-speed centrifugation can separate the product from the reaction system. Washing with deionized water can remove unreacted raw materials and impurities remaining on the precipitate surface. Vacuum drying can remove water and residual solvent from the precipitate, finally obtaining maleic anhydride-grafted polyglycerol-10 laurate.

[0021] This invention also discloses a method for preparing a novel thin film for making air column bags, comprising the following steps: S1. Ingredients and Premixing: Premix each component of layer A according to the formula to obtain layer A premix, and then dry it at 70~80℃ and vacuum degree -0.090~-0.095MPa for 4~6h; after drying each component of layer B according to the formula, mix them to obtain layer B premix. S2, Melting and Plasticizing and Extrusion: The A-layer premix and the B-layer premix are added to a single screw extruder for melting and plasticizing extrusion, and the temperature, feeding speed and back pressure of each extruder are controlled. S3. Co-extrusion and blowing: The molten material of layer A and layer B obtained in step S2 are fed into a three-layer co-extrusion spiral mandrel die and extruded. After extrusion, compressed air is introduced for blowing and cooling by an air ring. The thickness ratio of layer A: layer B: layer A of the film is controlled to be 1:(1~1.5):1. S4. Winding and post-treatment: After cooling and shaping, the film is treated with corona and then wound up. It is then cured at 23~27℃ and 45~55% relative humidity for 24~48h to obtain a new type of film for preparing air column bags.

[0022] By employing the above technical solutions, drying the A-layer premix under specific conditions removes moisture and reduces bubble generation during film processing. Drying the components of the B-layer before mixing reduces hydrolysis of easily hydrolyzed components, ensuring the stability of the B-layer material's performance. Controlling extruder process parameters during melt plasticizing extrusion ensures complete melting and uniform dispersion of the A and B layers, guaranteeing material processing performance. Using a three-layer co-extrusion spiral mandrel die for melt fusion allows for thorough integration of the A and B layers, while simultaneously adjusting the thickness ratio of each film layer to achieve synergistic performance across all layers. Post-extrusion blowing and air-ring cooling rapidly shapes the film, ensuring excellent forming effect and dimensional stability. Corona treatment of the cooled and shaped film increases surface tension, facilitating subsequent processing. Curing under specific temperature and humidity conditions promotes interlayer bonding, enhances interlayer strength, and accelerates the evaporation of residual solvents, ensuring film performance stability.

[0023] Preferably, in step S1, the premixing process of each component in layer A is as follows: linear low-density polyethylene, EPDM rubber, reactive pre-crosslinked hybrid toughening particles, ionic liquid intercalated modified hydrophobic hydrotalcite, maleic anhydride grafted polyethylene, ethylene-octene copolymer, antioxidant compound, processing aid, and dicyandiamide latent catalyst are added to a high-speed mixer and mixed at 800-1000 r / min at 40-50°C for 8-12 min. Then, maleic anhydride grafted polyglycerol-10 laurate is added, and mixing continues for 2-3 min. The premixing process of each component in layer B is as follows: Ethylene-vinyl alcohol copolymer, polyamide 6, ionic liquid intercalated modified hydrophobic hydrotalcite, maleic anhydride grafted ethylene-vinyl alcohol copolymer, and antioxidant are added sequentially to a vacuum drying oven and dried at 80~90℃ and vacuum degree -0.090~-0.095MPa for 4~6 hours. After drying, the material is transferred to a high-speed mixer and mixed at 30~40℃ and a speed of 600~800r / min for 5~8 minutes. In step S2, the screw diameter of the A-layer extruder is 60~70mm, the length-to-diameter ratio is 28~32:1, the compression ratio is 2.3~2.7:1; the feeding section is 150~160℃, the compression section is 170~180℃, the metering section is 185~195℃, the die head is 190~200℃, the screw speed is 40~60r / min, and the back pressure is 0.3~0.5MPa. The B-layer extruder uses a barrier screw with a diameter of 50-60mm, a length-to-diameter ratio of 30-35:1, and a compression ratio of 3.0-3.5:1. The feeding section has a temperature of 180-190℃, the compression section 200-210℃, the metering section 220-230℃, and the die head 225-235℃. The screw speed is 30-50 r / min, and the back pressure is 0.4-0.6 MPa. In step S3, the die diameter of the three-layer co-extrusion spiral mandrel die is 50~60mm, the die gap is 0.8~1.2mm, and the die temperature is 220~230℃; the blow-up ratio is 2.0~2.5, the draw ratio is 2.5~3.5; the air ring diameter is 80~120mm, the cooling air temperature is 20~25℃, and the condensation line height is 200~300mm. In step S4, the corona power during corona treatment is 300~400W, and the treatment speed is 15~25m / min; the winding tension during winding is 20~30N, and the winding speed is 15~25m / min.

[0024] By employing the above technical solution, the phased mixing of the components in layer A ensures thorough dispersion of the rigid filler, elastomer, and matrix resin, while reducing performance changes of maleic anhydride-grafted polyglycerol-10 laurate at high temperatures, thus guaranteeing the uniformity of the layer A components. The pre-drying and subsequent mixing of layer B components reduces the hydrolysis of ethylene-vinyl alcohol copolymer and polyamide 6, maintaining the structural and performance stability of the layer B material. By limiting the screw parameters and temperature gradient of the extruders for layers A and B, gradient melting and plasticization of each layer material can be achieved, ensuring the degree of plasticization and flow properties of the melt, while also controlling the processing temperature. The activation temperature is adapted to that of dicyandiamide-based latent catalysts; the parameter settings of the three-layer co-extrusion spiral mandrel die enable the full fusion of the A and B layer melts; the control of the blow-up ratio and draw ratio enables the film to form a uniform orientation structure; the parameter settings of the air ring and condensation line enable the film to cool rapidly and uniformly, ensuring the forming accuracy and dimensional stability of the film; the power and speed parameter control of the corona treatment enables the formation of uniform polar groups on the film surface, increasing the surface tension of the film; the matching of winding tension and speed reduces the stretching and wrinkling of the film during the winding process, ensuring the appearance quality and winding density of the film.

[0025] The beneficial effects of this invention are as follows: Linear low-density polyethylene (LDPE) serves as the film-forming substrate for layer A, providing basic mechanical properties and heat-sealing performance. EPDM rubber enhances the elastic recovery and weather resistance of layer A. Reactive pre-crosslinked hybrid toughening particles enhance the puncture resistance and dispersion stability of layer A, while also reacting with maleic anhydride-grafted polyethylene at the interface to improve interlayer bonding. Ionic liquid intercalation-modified hydrophobic hydrotalcite improves the gas barrier properties and permeability of layers A and B, reduces the gas and water vapor permeability coefficients, and enhances the mechanical properties of layers A and B. Maleic anhydride-grafted polyethylene improves the compatibility between polar and non-polar components in layer A, acting as an interfacial bridge. Maleic anhydride-grafted polyglycerol-10 laurate lowers the heat-sealing temperature of layer A, improves its processing fluidity, and reduces migration. Ethylene-octene copolymer further enhances the toughness and processing fluidity of layer A. The oxygen-resistant compound can inhibit the thermo-oxidative aging of layer A during processing and use; the processing aid can improve the melt lubrication and demolding effect of layer A, and prevent melt cracking; the dicyandiamide-based latent catalyst can catalyze the ring-opening addition reaction between the epoxy groups on the reactive pre-crosslinked hybrid toughening particles in layer A and the anhydride groups of the maleic anhydride graft, further enhancing the interfacial bonding strength of layer A; ethylene-vinyl alcohol copolymer and polyamide, as the core components of layer B, can provide excellent gas barrier properties and mechanical properties; maleic anhydride grafted ethylene-vinyl alcohol copolymer can improve the compatibility of each component in layer B and enhance the overall stability of layer B; the antioxidant can inhibit the thermo-oxidative aging of layer B during processing and use; the synergistic effect of each component makes the A / B / A three-layer co-extruded film have good mechanical properties, gas barrier properties, heat sealing properties, weather resistance and interlayer bonding properties. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The specific information on the raw materials used in the embodiments of the present invention is shown in Table 1.

[0028] Table 1

[0029] Example 1: This embodiment discloses a novel film for preparing air column bags. The film has an A / B / A three-layer co-extrusion structure with a total thickness of 80 μm. By weight, the raw materials for preparing layer A include: 45 parts linear low-density polyethylene, 8 parts EPDM rubber, 12 parts reactive pre-crosslinked hybrid toughening particles, 5 parts ionic liquid intercalated modified hydrophobic hydrotalcite, 3 parts maleic anhydride grafted polyethylene, 2 parts maleic anhydride grafted polyglycerol-10 laurate, 6 parts ethylene-octene copolymer, 0.3 parts antioxidant compound, 0.5 parts processing aid, and 0.1 parts dicyandiamide latent catalyst. By weight, the raw materials for preparing layer B include: 60 parts ethylene-vinyl alcohol copolymer, 15 parts polyamide 6, 8 parts ionic liquid intercalated modified hydrophobic hydrotalcite, 5 parts maleic anhydride grafted ethylene-vinyl alcohol copolymer, and 0.2 parts antioxidant.

[0030] The linear low-density polyethylene is a metallocene linear low-density polyethylene with a density of 0.912 g / cm³. 3 The melt flow index was 1.0 g / 10 min; the ethylene content in the EPDM rubber was 55 wt%; the grafting rate of maleic anhydride-grafted polyethylene was 0.8%; the grafting rate of maleic anhydride-grafted polyglycerol-10 laurate was 1.0%; the D of the dicyandiamide-based latent catalyst... 50 ≤5μm, activation temperature is 160℃; the grafting rate of maleic anhydride-grafted ethylene-vinyl alcohol copolymer is 0.5%. The antioxidant compound in layer A is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1, and the processing aid is composed of zinc stearate and fluoropolymer processing aid in a mass ratio of 1:1; the antioxidant in layer B is antioxidant 1010.

[0031] The raw materials for preparing reactive pre-crosslinked hybrid toughening particles, by weight, include: 90 parts of EPDM rubber, 800 parts of anhydrous toluene, 10 parts of m-chloroperoxybenzoic acid, 8 parts of tetraethyl orthosilicate, 4 parts of deionized water, 0.5 parts of dibutyltin dilaurate, 0.3 parts of bis(tert-butylperoxyisopropyl)benzene, and 200 parts of methanol.

[0032] The preparation method of reactive pre-crosslinked hybrid toughening particles includes the following steps: 1) Prepare a 20wt% m-chloroperoxybenzoic acid / anhydrous toluene solution by dissolving m-chloroperoxybenzoic acid in a portion of anhydrous toluene; add EPDM rubber to the remaining anhydrous toluene and stir at 300 r / min at 60℃ for 2 h; add the m-chloroperoxybenzoic acid / anhydrous toluene solution dropwise at a rate of 1 mL / min; after the addition is complete, stir at 300 r / min at 70℃ for 3 h to obtain an epoxidized EPDM rubber solution. 2) The epoxidized EPDM rubber solution was stirred at 250 r / min at 50℃ for 4 h, then tetraethyl orthosilicate, deionized water and dibutyltin dilaurate were added, and the mixture was stirred at 250 r / min at 50℃ for 12 h to obtain an organic-inorganic hybrid system. 3) First, remove toluene from the organic-inorganic hybrid system under reduced pressure, then add bis(tert-butylperoxyisopropyl)benzene to it, transfer it to a mixer, heat it to 160°C, control the speed of the mixer to 80 r / min and the filling coefficient to 0.7, and mix for 3 min. 4) Add the material after intensive mixing in step 3) to methanol, stir at 150 r / min for 5 min, then let it stand to settle for 1 h, vacuum filter, wash the filter cake with methanol 3 times, place the washed solid in a vacuum drying oven, dry at 80℃ and vacuum degree -0.090MPa for 4 h, crush and sieve to obtain reactive pre-crosslinked hybrid toughening particles with a particle size of 2 μm.

[0033] The raw materials for preparing ionic liquid intercalation modified hydrophobic hydrotalcite, by weight, include: 30 parts magnesium nitrate hexahydrate, 10 parts aluminum nitrate nonahydrate, 12 parts sodium hydroxide, 8 parts anhydrous sodium carbonate, 400 parts deionized water, 15 parts 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1 part silane coupling agent KH-570, and 50 parts anhydrous ethanol.

[0034] The preparation method of ionic liquid intercalation modified hydrophobic hydrotalcite includes the following steps: (1) Under nitrogen protection, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate were added to a portion of deionized water at 60°C to prepare a salt solution with a total metal salt concentration of 0.5 mol / L; sodium hydroxide and anhydrous sodium carbonate were added to a portion of deionized water at 60°C to prepare an alkaline solution with a total metal salt concentration of 1.0 mol / L; the salt solution and alkaline solution were simultaneously added dropwise to the reaction vessel at a rate of 2 mL / min, the pH of the reaction system was maintained at 9.5, the temperature was maintained at 60°C, and the reaction was aged for 18 h. After aging, the reaction solution was centrifuged at 8000 r / min for 15 min, the precipitate was collected, and the precipitate was washed three times with deionized water until the pH of the washing solution reached 6.8. The washed precipitate was placed in a vacuum drying oven and dried at 60°C and a vacuum of -0.090 MPa for 12 h to obtain the Mg-Al LDH precursor. (2) Add the Mg-Al LDH precursor to the remaining deionized water and disperse it for 30 min under ultrasonic power of 300 W and frequency of 20 kHz. Then transfer it to the reaction vessel, add 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, and stir the reaction at 250 r / min at 70 °C for 24 h. Centrifuge the reaction solution at 8000 r / min for 15 min, collect the precipitate, wash the precipitate three times with deionized water, place the washed precipitate in a vacuum drying oven, and dry it for 10 h at 70 °C and vacuum degree of -0.090 MPa to obtain ionic liquid intercalated modified LDH. (3) Add the ionic liquid intercalated modified LDH to anhydrous ethanol and stir at 200 r / min for 10 min. Add silane coupling agent KH-570 dropwise at a rate of 0.5 mL / min. After the addition is complete, stir the reaction at 150 r / min at 60 °C for 4 h. Centrifuge the reaction solution at 8000 r / min for 15 min, collect the precipitate, wash the precipitate three times with deionized water, place the washed precipitate in a vacuum drying oven, dry it at 80 °C and vacuum degree -0.090 MPa for 8 h, cool it to 25 °C, grind it through a 400 mesh sieve to obtain ionic liquid intercalated modified hydrophobic hydrotalcite.

[0035] The raw materials for preparing maleic anhydride-grafted polyglycerol-10 laurate, by weight, include: 90 parts of polyglycerol-10 laurate, 5 parts of maleic anhydride, 0.1 parts of hydroquinone, 150 parts of anhydrous toluene, and 100 parts of methanol. The preparation method of maleic anhydride-grafted polyglycerol-10 laurate includes the following steps: a. Polyglycerol-10 laurate and anhydrous toluene were added to a reaction vessel and stirred at 70°C at 200 r / min for 1 h to dissolve them. Then maleic anhydride and hydroquinone were added, the temperature was raised to 90°C, and the mixture was stirred at 250 r / min for 6 h to react. b. After the reaction is complete, cool down to 40°C, add methanol, stir at 250 r / min for 1 h, centrifuge the reaction solution at 8000 r / min for 15 min, collect the precipitate, wash the precipitate three times with deionized water, and then place the washed precipitate in a vacuum drying oven and dry it at 70°C and a vacuum of -0.090 MPa for 6 h to obtain maleic anhydride-grafted polyglycerol-10 laurate.

[0036] This embodiment also discloses a method for preparing a novel thin film for making air column bags, comprising the following steps: S1. Ingredients and Premixing: Linear low-density polyethylene, EPDM rubber, reactive pre-crosslinked hybrid toughening particles, ionic liquid intercalated modified hydrophobic hydrotalcite, maleic anhydride grafted polyethylene, ethylene-octene copolymer, antioxidant compound, processing aids, and dicyandiamide latent catalyst were added to a high-speed mixer according to the specified ratio. The mixture was mixed at 800 r / min for 8 min at 40 °C. Then, maleic anhydride grafted polyglycerol-10 laurate was added, and the mixture was mixed for another 2 min to obtain layer A premix. The premix was then dried at 70 °C and a vacuum of -0.090 MPa for 4 h. Ethylene-vinyl alcohol copolymer, polyamide 6, ionic liquid intercalated modified hydrophobic hydrotalcite, maleic anhydride grafted ethylene-vinyl alcohol copolymer, and antioxidant were sequentially added to a vacuum drying oven and dried at 80℃ and a vacuum of -0.090MPa for 4 hours. After drying, the material was transferred to a high-speed mixer and mixed at 30℃ and a speed of 600r / min for 5 minutes. S2, Melt Plasticization and Extrusion: Add the A-layer premix to a single-screw extruder. The screw diameter of the A-layer extruder is 60mm, the length-to-diameter ratio is 28:1, and the compression ratio is 2.3:1. The temperature settings are: feeding section 150℃, compression section 170℃, metering section 185℃, die head 190℃, screw speed 40r / min, and back pressure 0.3MPa. The B-layer premix is ​​added to a single-screw extruder for melt plasticizing and extrusion. The B-layer extruder uses a barrier screw with a diameter of 50 mm, a length-to-diameter ratio of 30:1, and a compression ratio of 3.0:1. The temperature settings are as follows: feeding section 180℃, compression section 200℃, metering section 220℃, die head 225℃, screw speed 30 r / min, and back pressure 0.4 MPa. S3, Co-extrusion and Inflation: Melt merging: The molten material of layer A and the molten material of layer B obtained in step S2 are fed into a three-layer co-extrusion spiral mandrel die for merging. The die diameter is 50 mm, the die gap is 0.8 mm, and the die temperature is 220 °C. Inflation and Cooling: After the melt is extruded from the die, compressed air is immediately introduced for inflation, with the inflation ratio controlled at 2.0 and the draw ratio at 2.5. After inflation, air ring cooling is performed. The air ring diameter is 80 mm, the cooling air temperature is 20 °C, and the condensation line height is 200 mm, so as to achieve rapid cooling and shaping of the film and suppress uneven crystallization. Thickness control: The film thickness is monitored in real time using an online thickness gauge (accuracy ±1μm). The thickness gauge scanning speed is 10cm / s. The extruder speed and stretching speed are adjusted by feedback to ensure that the thickness ratio of layer A: layer B: layer A is 1:1:1, and the total thickness is controlled to be 80μm. S4. Rewinding and Post-processing: Corona treatment: The cooled and shaped film is treated by a corona treatment machine, with the corona power controlled at 300W and the processing speed at 15m / min; Rewinding: The corona-treated film enters the rewinding machine, with the winding tension controlled at 20N and the winding speed at 15m / min; Curing: The wound film is placed in a curing chamber, and the curing temperature is controlled at 23℃ and the relative humidity at 45% for 24 hours to obtain a new type of film for preparing air column bags.

[0037] Example 2: This embodiment discloses a novel film for preparing air column bags. The film has an A / B / A three-layer co-extrusion structure with a total thickness of 120 μm. By weight, the raw materials for preparing layer A include: 55 parts linear low-density polyethylene, 12 parts EPDM rubber, 18 parts reactive pre-crosslinked hybrid toughening particles, 8 parts ionic liquid intercalated modified hydrophobic hydrotalcite, 5 parts maleic anhydride grafted polyethylene, 4 parts maleic anhydride grafted polyglycerol-10 laurate, 10 parts ethylene-octene copolymer, 0.6 parts antioxidant compound, 1.0 part processing aid, and 0.3 parts dicyandiamide latent catalyst. By weight, the raw materials for preparing layer B include: 70 parts ethylene-vinyl alcohol copolymer, 20 parts polyamide 6, 12 parts ionic liquid intercalated modified hydrophobic hydrotalcite, 8 parts maleic anhydride grafted ethylene-vinyl alcohol copolymer, and 0.4 parts antioxidant.

[0038] The linear low-density polyethylene is a metallocene linear low-density polyethylene with a density of 0.918 g / cm³. 3 The melt flow index was 2.0 g / 10 min; the ethylene content in the EPDM rubber was 65 wt%; the grafting rate of maleic anhydride-grafted polyethylene was 1.2%; the grafting rate of maleic anhydride-grafted polyglycerol-10 laurate was 1.5%; the D of the dicyandiamide-based latent catalyst... 50 ≤5μm, activation temperature is 180℃; the grafting rate of maleic anhydride-grafted ethylene-vinyl alcohol copolymer is 0.8%. The antioxidant compound in layer A is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2, and the processing aid is composed of zinc stearate and fluoropolymer processing aid in a mass ratio of 2:1; the antioxidant in layer B is antioxidant 168.

[0039] The raw materials for preparing reactive pre-crosslinked hybrid toughening particles, by weight, include: 100 parts of EPDM rubber, 900 parts of anhydrous toluene, 15 parts of m-chloroperoxybenzoic acid, 12 parts of tetraethyl orthosilicate, 6 parts of deionized water, 0.8 parts of dibutyltin dilaurate, 0.6 parts of bis(tert-butylperoxyisopropyl)benzene, and 300 parts of methanol.

[0040] The preparation method of reactive pre-crosslinked hybrid toughening particles includes the following steps: 1) Prepare a 30wt% m-chloroperoxybenzoic acid / anhydrous toluene solution by dissolving m-chloroperoxybenzoic acid in a portion of anhydrous toluene; add EPDM rubber to the remaining anhydrous toluene and stir at 400 r / min at 70℃ for 3 h; add the m-chloroperoxybenzoic acid / anhydrous toluene solution dropwise at a rate of 2 mL / min; after the addition is complete, stir at 400 r / min at 75℃ for 4 h to obtain an epoxidized EPDM rubber solution. 2) The epoxidized EPDM rubber solution was stirred at 350 r / min at 60℃ for 6 h, and then tetraethyl orthosilicate, deionized water and dibutyltin dilaurate were added. The mixture was stirred at 350 r / min at 60℃ for 16 h to obtain an organic-inorganic hybrid system. 3) First, remove toluene from the organic-inorganic hybrid system under reduced pressure, then add bis(tert-butylperoxyisopropyl)benzene to it, transfer it to a mixer, heat it to 170°C, control the speed of the mixer to 100 r / min and the filling coefficient to 0.8, and mix for 5 min. 4) Add the material after intensive mixing in step 3) to methanol, stir at 200 r / min for 10 min, then let it stand to settle for 2 h, vacuum filter, wash the filter cake with methanol 4 times, place the washed solid in a vacuum drying oven, dry at 90℃ and vacuum degree -0.095MPa for 6 h, crush and sieve to obtain reactive pre-crosslinked hybrid toughening particles with a particle size of 4 μm.

[0041] The raw materials for preparing ionic liquid intercalation modified hydrophobic hydrotalcite, by weight, include: 34 parts magnesium nitrate hexahydrate, 14 parts aluminum nitrate nonahydrate, 16 parts sodium hydroxide, 10 parts anhydrous sodium carbonate, 600 parts deionized water, 20 parts 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 2 parts silane coupling agent KH-570, and 80 parts anhydrous ethanol.

[0042] The preparation method of ionic liquid intercalation modified hydrophobic hydrotalcite includes the following steps: (1) Under nitrogen protection, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate were added to a portion of deionized water at 70°C to prepare a salt solution with a total metal salt concentration of 0.8 mol / L; sodium hydroxide and anhydrous sodium carbonate were added to a portion of deionized water at 70°C to prepare an alkaline solution with a total metal salt concentration of 1.5 mol / L; the salt solution and alkaline solution were simultaneously added dropwise to the reaction vessel at a rate of 3 mL / min, the pH of the reaction system was maintained at 10.5, the temperature was maintained at 70°C, and the reaction was aged for 24 h. After aging, the reaction solution was centrifuged at 10000 r / min for 20 min, the precipitate was collected, and the precipitate was washed 4 times with deionized water until the pH of the washing solution reached 7.2. The washed precipitate was placed in a vacuum drying oven and dried at 70°C and a vacuum of -0.095 MPa for 14 h to obtain the Mg-Al LDH precursor. (2) Add the Mg-Al LDH precursor to the remaining deionized water and disperse it for 40 min under ultrasonic power of 400 W and frequency of 30 kHz. Then transfer it to the reaction vessel, add 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine salt, stir the reaction at 350 r / min at 80 °C for 30 h, centrifuge the reaction solution at 10000 r / min for 20 min, collect the precipitate, wash the precipitate 4 times with deionized water, place the washed precipitate in a vacuum drying oven, and dry it for 12 h at 80 °C and vacuum degree of -0.095 MPa to obtain ionic liquid intercalated modified LDH. (3) Add the ionic liquid intercalated modified LDH to anhydrous ethanol and stir at 300 r / min for 15 min. Add silane coupling agent KH-570 dropwise at a rate of 1 mL / min. After the addition is complete, stir the reaction at 200 r / min at 70 °C for 6 h. Centrifuge the reaction solution at 10000 r / min for 20 min, collect the precipitate, wash the precipitate 4 times with deionized water, place the washed precipitate in a vacuum drying oven, dry it at 90 °C and vacuum degree -0.095 MPa for 10 h, cool it to 30 °C, grind it through a 450 mesh sieve to obtain ionic liquid intercalated modified hydrophobic hydrotalcite.

[0043] The raw materials for preparing maleic anhydride-grafted polyglycerol-10 laurate, by weight, include: 100 parts of polyglycerol-10 laurate, 8 parts of maleic anhydride, 0.2 parts of hydroquinone, 200 parts of anhydrous toluene, and 150 parts of methanol. The preparation method of maleic anhydride-grafted polyglycerol-10 laurate includes the following steps: a. Polyglycerol-10 laurate and anhydrous toluene were added to a reaction vessel and stirred at 300 r / min at 80°C for 2 h to dissolve. Then maleic anhydride and hydroquinone were added, the temperature was raised to 100°C, and the mixture was stirred at 350 r / min for 8 h. b. After the reaction is complete, cool down to 50°C, add methanol, stir at 350 r / min for 2 h, centrifuge the reaction solution at 10000 r / min for 20 min, collect the precipitate, wash the precipitate 4 times with deionized water, and then place the washed precipitate in a vacuum drying oven and dry it at 80°C and a vacuum degree of -0.095 MPa for 8 h to obtain maleic anhydride-grafted polyglycerol-10 laurate.

[0044] This embodiment also discloses a method for preparing a novel thin film for making air column bags, comprising the following steps: S1. Ingredients and Premixing: Linear low-density polyethylene, EPDM rubber, reactive pre-crosslinked hybrid toughening particles, ionic liquid intercalated modified hydrophobic hydrotalcite, maleic anhydride grafted polyethylene, ethylene-octene copolymer, antioxidant compound, processing aids, and dicyandiamide latent catalyst were added to a high-speed mixer according to the specified ratio. The mixture was mixed at 1000 r / min for 12 min at 50 °C. Then, maleic anhydride grafted polyglycerol-10 laurate was added, and the mixture was mixed for another 3 min to obtain layer A premix. The premix was then dried at 80 °C and a vacuum of -0.095 MPa for 6 h. Ethylene-vinyl alcohol copolymer, polyamide 6, ionic liquid intercalated modified hydrophobic hydrotalcite, maleic anhydride grafted ethylene-vinyl alcohol copolymer, and antioxidant were sequentially added to a vacuum drying oven and dried at 90℃ and a vacuum of -0.095MPa for 6 hours. After drying, the material was transferred to a high-speed mixer and mixed at 40℃ and a speed of 800r / min for 8 minutes. S2, Melt Plasticization and Extrusion: Add the A-layer premix to a single-screw extruder. The screw diameter of the A-layer extruder is 70mm, the length-to-diameter ratio is 32:1, and the compression ratio is 2.7:1. Temperature settings: feeding section 160℃, compression section 180℃, metering section 195℃, die head 200℃, screw speed 60r / min, back pressure 0.5MPa. The B-layer premix is ​​added to a single-screw extruder for melt plasticizing and extrusion. The B-layer extruder uses a barrier screw with a diameter of 60 mm, a length-to-diameter ratio of 35:1, and a compression ratio of 3.5:1. The temperature settings are as follows: feeding section 190℃, compression section 210℃, metering section 230℃, die head 235℃, screw speed 50 r / min, and back pressure 0.6 MPa. S3, Co-extrusion and Inflation: Melt merging: The molten material of layer A and the molten material of layer B obtained in step S2 are fed into a three-layer co-extrusion spiral mandrel die head for merging. The die head diameter is 60mm, the die opening gap is 1.2mm, and the die head temperature is 230℃. Inflation and Cooling: After the melt is extruded from the die, compressed air is immediately introduced for inflation, with the inflation ratio controlled at 2.5 and the draw ratio at 3.5. After inflation, air ring cooling is performed. The air ring diameter is 120mm, the cooling air temperature is 25℃, and the condensation line height is 300mm, so as to achieve rapid cooling and shaping of the film and suppress uneven crystallization. Thickness control: The film thickness is monitored in real time using an online thickness gauge (accuracy ±1μm). The thickness gauge scanning speed is 15cm / s. The extruder speed and drawing speed are adjusted by feedback to ensure that the thickness ratio of layer A: layer B: layer A is 1:1.5:1, and the total thickness is controlled to be 120μm. S4. Rewinding and Post-processing: Corona treatment: The cooled and shaped film is treated by a corona treatment machine, with the corona power controlled at 400W and the processing speed at 25m / min; Rewinding: The corona-treated film enters the rewinding machine, with the winding tension controlled at 30N and the winding speed at 25m / min; Curing: The wound film is placed in a curing chamber, and the curing temperature is controlled at 27°C and the relative humidity at 55% for 48 hours to obtain a new type of film for preparing air column bags.

[0045] Example 3: This embodiment discloses a novel film for preparing air column bags. The film has an A / B / A three-layer co-extrusion structure with a total thickness of 100 μm. By weight, the raw materials for preparing layer A include: 50 parts linear low-density polyethylene, 10 parts EPDM rubber, 15 parts reactive pre-crosslinked hybrid toughening particles, 6 parts ionic liquid intercalated modified hydrophobic hydrotalcite, 4 parts maleic anhydride grafted polyethylene, 3 parts maleic anhydride grafted polyglycerol-10 laurate, 8 parts ethylene-octene copolymer, 0.5 parts antioxidant compound, 0.8 parts processing aid, and 0.2 parts dicyandiamide latent catalyst. By weight, the raw materials for preparing layer B include: 65 parts ethylene-vinyl alcohol copolymer, 18 parts polyamide 6, 10 parts ionic liquid intercalated modified hydrophobic hydrotalcite, 7 parts maleic anhydride grafted ethylene-vinyl alcohol copolymer, and 0.3 parts antioxidant.

[0046] The linear low-density polyethylene is a metallocene linear low-density polyethylene with a density of 0.915 g / cm³. 3 The melt flow index was 1.5 g / 10 min; the ethylene content in the EPDM rubber was 60 wt%; the grafting rate of maleic anhydride-grafted polyethylene was 1.0%; the grafting rate of maleic anhydride-grafted polyglycerol-10 laurate was 1.2%; the D of the dicyandiamide-based latent catalyst... 50≤5μm, activation temperature is 170℃; the grafting rate of maleic anhydride-grafted ethylene-vinyl alcohol copolymer is 0.7%. The antioxidant compound in layer A is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.5, and the processing aid is composed of zinc stearate and fluoropolymer processing aid in a mass ratio of 1.5:1; the antioxidant in layer B is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0047] The raw materials for preparing reactive pre-crosslinked hybrid toughening particles, by weight, include: 95 parts of EPDM rubber, 850 parts of anhydrous toluene, 12 parts of m-chloroperoxybenzoic acid, 10 parts of tetraethyl orthosilicate, 5 parts of deionized water, 0.6 parts of dibutyltin dilaurate, 0.4 parts of bis(tert-butylperoxyisopropyl)benzene, and 250 parts of methanol.

[0048] The preparation method of reactive pre-crosslinked hybrid toughening particles includes the following steps: 1) Prepare a 25wt% m-chloroperoxybenzoic acid / anhydrous toluene solution by dissolving m-chloroperoxybenzoic acid in a portion of anhydrous toluene; add EPDM rubber to the remaining anhydrous toluene and stir at 350 r / min at 65℃ for 2.5 h; add the m-chloroperoxybenzoic acid / anhydrous toluene solution dropwise at a rate of 1.5 mL / min; after the addition is complete, stir at 350 r / min at 72℃ for 3.5 h to obtain an epoxidized EPDM rubber solution. 2) The epoxidized EPDM rubber solution was stirred at 300 r / min at 55℃ for 5 h, and then tetraethyl orthosilicate, deionized water and dibutyltin dilaurate were added. The mixture was stirred at 300 r / min at 55℃ for 14 h to obtain an organic-inorganic hybrid system. 3) First, remove toluene from the organic-inorganic hybrid system under reduced pressure, then add bis(tert-butylperoxyisopropyl)benzene to it, transfer it to a mixer, heat it to 165℃, control the speed of the mixer to 90r / min and the filling coefficient to 0.8, and mix for 4min. 4) Add the material after intensive mixing in step 3) to methanol, stir at 175 r / min for 8 min, then let it stand to settle for 1.5 h, vacuum filter, wash the filter cake with methanol 4 times, place the washed solid in a vacuum drying oven, dry at 85℃ and vacuum degree -0.092 MPa for 5 h, crush and sieve to obtain reactive pre-crosslinked hybrid toughening particles with a particle size of 3 μm.

[0049] The raw materials for preparing ionic liquid intercalation modified hydrophobic hydrotalcite, by weight, include: 32 parts magnesium nitrate hexahydrate, 12 parts aluminum nitrate nonahydrate, 14 parts sodium hydroxide, 9 parts anhydrous sodium carbonate, 500 parts deionized water, 18 parts 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1.5 parts silane coupling agent KH-570, and 65 parts anhydrous ethanol.

[0050] The preparation method of ionic liquid intercalation modified hydrophobic hydrotalcite includes the following steps: (1) Under nitrogen protection, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate were added to a portion of deionized water at 65°C to prepare a salt solution with a total metal salt concentration of 0.6 mol / L; sodium hydroxide and anhydrous sodium carbonate were added to a portion of deionized water at 65°C to prepare an alkaline solution with a total metal salt concentration of 1.2 mol / L; the salt solution and alkaline solution were simultaneously added dropwise to the reaction vessel at a rate of 2.5 mL / min, the pH of the reaction system was maintained at 10.0, the temperature was maintained at 65°C, and the reaction was aged for 21 h. After aging, the reaction solution was centrifuged at 9000 r / min for 18 min, the precipitate was collected, and the precipitate was washed 4 times with deionized water until the pH of the washing solution reached 7.0. The washed precipitate was placed in a vacuum drying oven and dried at 65°C and a vacuum of -0.092 MPa for 13 h to obtain Mg-Al LDH precursor; (2) The Mg-Al LDH precursor was added to the remaining deionized water and dispersed for 35 min under ultrasonic power of 350 W and frequency of 25 kHz. Then it was transferred to a reaction vessel and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine salt was added. The reaction was stirred at 300 r / min at 75 °C for 27 h. The reaction solution was centrifuged at 9000 r / min for 18 min, the precipitate was collected, and the precipitate was washed 4 times with deionized water. The washed precipitate was placed in a vacuum drying oven and dried at 75 °C and vacuum degree of -0.092 MPa for 11 h to obtain ionic liquid intercalated modified LDH. (3) Add the ionic liquid intercalated modified LDH to anhydrous ethanol and stir at 250 r / min for 12 min. Add silane coupling agent KH-570 dropwise at a rate of 0.8 mL / min. After the addition is complete, stir the reaction at 175 r / min at 65 °C for 5 h. Centrifuge the reaction solution at 9000 r / min for 18 min, collect the precipitate, wash the precipitate 4 times with deionized water, place the washed precipitate in a vacuum drying oven, dry it at 85 °C and vacuum degree -0.092 MPa for 9 h, cool it to 28 °C, grind it through a 420 mesh sieve to obtain ionic liquid intercalated modified hydrophobic hydrotalcite.

[0051] The raw materials for preparing maleic anhydride-grafted polyglycerol-10 laurate, by weight, include: 95 parts of polyglycerol-10 laurate, 6 parts of maleic anhydride, 0.15 parts of hydroquinone, 175 parts of anhydrous toluene, and 125 parts of methanol. The preparation method of maleic anhydride-grafted polyglycerol-10 laurate includes the following steps: a. Polyglycerol-10 laurate and anhydrous toluene were added to a reaction vessel and stirred at 250 r / min at 75°C for 1.5 h to dissolve. Then maleic anhydride and hydroquinone were added, the temperature was raised to 95°C, and the mixture was stirred at 300 r / min for 7 h. b. After the reaction is complete, cool down to 45°C, add methanol, stir at 300 r / min for 1.5 h, centrifuge the reaction solution at 9000 r / min for 18 min, collect the precipitate, wash the precipitate 4 times with deionized water, and then place the washed precipitate in a vacuum drying oven and dry it at 75°C and a vacuum degree of -0.092 MPa for 7 h to obtain maleic anhydride grafted polyglycerol-10 laurate.

[0052] This embodiment also discloses a method for preparing a novel thin film for making air column bags, comprising the following steps: S1. Ingredients and Premixing: Linear low-density polyethylene, EPDM rubber, reactive pre-crosslinked hybrid toughening particles, ionic liquid intercalated modified hydrophobic hydrotalcite, maleic anhydride grafted polyethylene, ethylene-octene copolymer, antioxidant compound, processing aids, and dicyandiamide latent catalyst were added to a high-speed mixer according to the specified ratio. The mixture was mixed at 900 r / min for 10 min at 45 °C. Then, maleic anhydride grafted polyglycerol-10 laurate was added, and the mixture was mixed for another 3 min to obtain layer A premix. The premix was then dried at 75 °C and a vacuum of -0.092 MPa for 5 h. Ethylene-vinyl alcohol copolymer, polyamide 6, ionic liquid intercalated modified hydrophobic hydrotalcite, maleic anhydride grafted ethylene-vinyl alcohol copolymer, and antioxidant were sequentially added to a vacuum drying oven and dried at 85℃ and a vacuum of -0.092MPa for 5 hours. After drying, the material was transferred to a high-speed mixer and mixed at 35℃ and a speed of 700r / min for 6 minutes. S2, Melt Plasticization and Extrusion: Add the A-layer premix to a single-screw extruder. The screw diameter of the A-layer extruder is 65mm, the length-to-diameter ratio is 30:1, and the compression ratio is 2.5:1. Temperature settings: feeding section 155℃, compression section 175℃, metering section 190℃, die head 195℃, screw speed 50r / min, back pressure 0.4MPa. The B-layer premix is ​​added to a single-screw extruder for melt plasticizing and extrusion. The B-layer extruder uses a barrier screw with a diameter of 55 mm, a length-to-diameter ratio of 32:1, and a compression ratio of 3.2:1. The temperature settings are as follows: feeding section 185℃, compression section 205℃, metering section 225℃, die head 230℃, screw speed 40 r / min, and back pressure 0.5 MPa. S3, Co-extrusion and Inflation: Melt merging: The molten material of layer A and the molten material of layer B obtained in step S2 are fed into a three-layer co-extrusion spiral mandrel die for merging. The die diameter is 55mm, the die gap is 1.0mm, and the die temperature is 225℃. Inflation and Cooling: After the melt is extruded from the die, compressed air is immediately introduced for inflation, with the inflation ratio controlled at 2.2 and the draw ratio at 3.0. After inflation, air ring cooling is performed. The air ring diameter is 100mm, the cooling air temperature is 22℃, and the condensation line height is 250mm, so as to achieve rapid cooling and shaping of the film and suppress uneven crystallization. Thickness control: The film thickness is monitored in real time using an online thickness gauge (accuracy ±1μm). The thickness gauge scanning speed is 12cm / s. The extruder speed and stretching speed are adjusted by feedback to ensure that the thickness ratio of layer A: layer B: layer A is 1:1.2:1, and the total thickness is controlled to 100μm. S4. Rewinding and Post-processing: Corona treatment: The cooled and shaped film is treated by a corona treatment machine, with the corona power controlled at 350W and the processing speed at 20m / min; Rewinding: The corona-treated film enters the rewinding machine, with the winding tension controlled at 25N and the winding speed at 20m / min; Curing: The wound film is placed in a curing chamber, and the curing temperature is controlled at 25℃ and the relative humidity at 50% for 36 hours to obtain a new type of film for preparing air column bags.

[0053] Comparative Example 1: A novel film for preparing air column bags and its preparation method are disclosed, which differ from Example 3 only in that: reactive pre-crosslinked hybrid toughening particles are not added, and EPDM rubber of equal mass is used instead.

[0054] Comparative Example 2: A novel thin film for preparing air column bags and its preparation method are different from those in Example 3 only in that: no ionic liquid intercalation modified hydrophobic hydrotalcite is added, and an equal mass of unmodified Mg-Al LDH is used instead (unmodified LDH is prepared by co-precipitation of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, sodium hydroxide and sodium carbonate, omitting the operations of steps (2) and (3)).

[0055] Comparative Example 3: A novel thin film for preparing air column bags and its preparation method are disclosed. The only difference between this film and Example 3 is that bis(tert-butylperoxyisopropyl)benzene is not added during the preparation of reactive pre-crosslinked hybrid toughening particles, and step 3 is omitted.

[0056] Comparative Example 4: A novel thin film for preparing gas column bags and its preparation method are different from those in Example 3 only in that: when preparing hydrophobic hydrotalcite modified by ionic liquid intercalation, the hydrophobic modification of silane coupling agent KH-570 was not carried out (i.e., step (3) was omitted).

[0057] Comparative Example 5: A novel film for preparing air column bags and its preparation method are disclosed, which differ from Example 3 only in that maleic anhydride-grafted polyethylene is not added.

[0058] Comparative Example 6: A novel film for preparing air column bags and its preparation method are disclosed, which differ from Example 3 only in that maleic anhydride-grafted polyglycerol-10 laurate is not added, but is replaced by an equal mass of metallocene linear low-density polyethylene.

[0059] Comparative Example 7: A novel film for preparing air column bags and its preparation method are disclosed, which differ from Example 3 only in that: ethylene-octene copolymer is not added, but replaced by an equal mass of metallocene linear low-density polyethylene.

[0060] Comparative Example 8: The film adopts a traditional five-layer co-extruded film structure (PE / adhesive / PA / adhesive / PE), with a total thickness of 60~70μm and a thickness ratio of 2:0.5:1:0.5:2 for each layer. Among them, PE is ordinary metallocene linear low-density polyethylene (the same type of metallocene linear low-density polyethylene used in Example 3), PA is ordinary polyamide 6 (the same type of polyamide 6 used in Example 3), and adhesive is commercially available polyurethane adhesive. The preparation process adopts the traditional five-layer co-extruded blow molding process.

[0061] The tensile properties, right-angle tear strength, puncture resistance, oxygen permeability, water vapor permeability, heat seal performance, hot tack strength, weather resistance, inflatable drop performance, long-term static pressure retention, migration test, and interlayer peel strength of the films obtained in Examples 1-3 and Comparative Examples 1-8 were tested. The testing methods and standards for each property are as follows: 1. Tensile properties: Tested according to "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets" (GB / T1040.3-2006), using type II specimens with specimen size of 150mm × 10mm × specimen thickness, tensile speed of 500mm / min, test temperature of 23±2℃, and relative humidity of 50±5%. The tensile strength and elongation at break of the film in the longitudinal direction (MD) and transverse direction (TD) were tested separately. Five specimens were tested in each group, and the average value was taken.

[0062] 2. Right-angle tear strength: Tested according to "Determination of right-angle tear performance of plastics" (GB / T 1130-2022), with sample size of 100mm×25mm×sample thickness, tear speed of 500mm / min, test temperature of 23±2℃, relative humidity of 50±5%, 5 samples per group, and average value.

[0063] 3. Puncture resistance: Tested according to the standard "Dry lamination and extrusion lamination of plastic composite films and bags for packaging" (GB / T 10004-2008). A Φ20mm ball probe with a probe diameter of 20mm was used. The puncture speed was 200mm / min, the test temperature was 23±2℃, and the relative humidity was 50±5%. The maximum puncture force (puncture resistance) and puncture displacement were recorded. Five samples were tested in each group, and the average value was taken.

[0064] 4. Oxygen Transmission Rate (OTR): Tested according to the "Test Method for Gas Transmission Rate of Plastic Films and Sheets - Differential Pressure Method" (GB / T19789-2005), using the isobaric method, with a test temperature of 23±2℃, relative humidity of 50±5%, and a test area of ​​50cm². 2 The pressure difference was 0.1 MPa, and three samples were tested in each group. The average value was taken.

[0065] 5. Water vapor transmission rate (WVTR): Tested according to the standard "Determination of water vapor transmission rate of packaging materials plastic films and sheets - Electrolytic sensor method" (GB / T 31331-2014), with a test temperature of 38±1℃, relative humidity of 90±2%, and a test area of ​​50cm². 2 Three samples were tested in each group, and the average value was taken.

[0066] 6. Heat sealing performance: Tested according to the "Test Method for Heat Sealing Performance of Plastic Films" (GB / T 2358-2020). The heat sealing pressure is 0.3±0.05MPa, the heat sealing time is 1±0.1s, and the heat sealing temperature starts from 80℃ and increases in increments of 5℃. The heat sealing strength is tested to determine the initial heat sealing temperature (the lowest temperature when the heat sealing strength is ≥1.5N / 15mm) and the maximum heat sealing temperature (the temperature when the heat sealing strength drops to 80% of the maximum value). The heat sealing window = maximum heat sealing temperature - initial heat sealing temperature. Five samples are tested in each group, and the average value is taken.

[0067] 7. Hot tack strength: Tested according to "Test methods for heat sealing properties of plastic films and sheets - Part 2: Hot tack strength" (GB / T 2358-2020 Appendix A). The test is conducted within 0.5±0.05s after heat sealing. The heat sealing temperature is the initial heat sealing temperature +10℃, the heat sealing pressure is 0.3MPa, the test speed is 500mm / min, and 5 samples are tested in each group. The average value is taken.

[0068] 8. Weather resistance: Tested according to "Laboratory Light Source Exposure Test Methods for Plastics - Part 3: Fluorescent Ultraviolet Lamps" (GB / T16422.3-2014), using a QUV accelerated aging test chamber, UVA-340 lamp tube, and irradiation intensity of 0.76W / m². 2 @340nm, the test conditions are 60℃ / 8h light exposure, 50℃ / 4h condensation cycle, and after aging for 500h, the tensile strength retention rate is tested (tensile strength after aging / tensile strength before aging × 100%). Five samples are tested in each group, and the average value is taken.

[0069] 9. Inflatable drop performance: The film was made into a standard air column bag (300mm×400mm, air column diameter 20mm), inflated to 0.05±0.005MPa, and left to stand for 30min at 23±2℃ and 50±5% relative humidity. Then, it was dropped freely from a height of 1.2±0.05m onto a cement floor (hardness ≥60Shore D). Each sample was dropped 10 times, and the breakage rate (number of broken samples / total number of samples × 100%) and leakage rate (number of leaking samples / total number of samples × 100%) were recorded. 10 samples were tested in each group.

[0070] 10. Long-term static pressure retention rate: The inflated air column bag was placed in an environment of 23±2℃ and 50±5% relative humidity for 30 days. The air column pressure was tested at 0 days and 30 days respectively. Static pressure retention rate = (pressure at 30 days / pressure at 0 days) × 100%. 10 samples were tested in each group and the average value was taken.

[0071] 11. Migration test: The film sample was placed in an environment of 60±2℃ and 50±5% relative humidity for accelerated aging for 7 days. The heat seal strength retention rate before and after aging was tested. At the same time, the surface condition of the film was observed to determine whether there was migration precipitation (no stickiness or precipitation on the surface means no migration).

[0072] 12. Interlayer peel strength: Tested according to "Determination of interlayer peel strength of plastic films and sheets" (GB / T 27707-2011), with a sample size of 150mm×15mm, a peeling speed of 300mm / min, and a test temperature of 23±2℃. Five samples were tested in each group, and the average value was taken.

[0073] The results are shown in Tables 2 and 3.

[0074] Table 2 Mechanical, Barrier, Drop, and Static Pressure Retention Properties

[0075] Table 3 Heat sealing and weather resistance properties

[0076] Using Example 3 as the control group, the performance differences and causes of Comparative Examples 1-8 are analyzed as follows: Comparative Example 1: Without the addition of reactive pre-crosslinked hybrid toughening particles, and replaced with an equal mass of ordinary EPDM rubber, the tensile strength decreased from 43.1 MPa to 31.8 MPa (a decrease of 26.2%), the puncture strength decreased from 54 N to 36 N (a decrease of 33.3%), and the oxygen permeability decreased from 12.2 cm⁻¹. 3 / m 2 • 24h • 0.1MPa rose to 22.9cm 3 / m 2 • 24h • 0.1MPa (increase of 87.7%), water vapor transmission rate increased from 2.4g / m 2 • Increased to 4.6g / m² in 24 hours 2 • Over 24 hours (an increase of 91.7%), the 1.2m drop failure rate increased from 0% to 18%, the 30-day static pressure retention rate decreased from 95.7% to 79.5% (a decrease of 16.9%), the initial heat sealing temperature increased from 90℃ to 99℃, the heat seal strength decreased from 34.1N / 15mm to 21.2N / 15mm (a decrease of 37.8%), the hot bond strength decreased from 15.9N / 15mm to 8.1N / 15mm (a decrease of 49.1%), and the interlayer peel strength decreased from 2.4N / 15mm to 1.3N / 15mm (a decrease of 45.8%). Under the catalytic acceleration of dicyandiamide-based latent catalysts, the epoxy groups on the surface of reactive pre-crosslinked hybrid toughening particles rapidly undergo ring-opening addition reactions with the anhydride groups of maleic anhydride-grafted polyethylene, forming a stable ester-bonded chemical interface. Simultaneously, nano-SiO2 provides rigid support and crazing within the matrix. The slightly pre-crosslinked structure ensures stable particle dispersion and dissipates impact energy during melt processing. Without this component, the aforementioned interfacial chemical reactions cannot occur, the nanoscale reinforcing phase is difficult to disperse uniformly and is prone to agglomeration, resulting in the material's inability to effectively dissipate energy and inhibit crack propagation under tensile and puncture stresses, thus significantly reducing mechanical properties. Furthermore, the decreased interfacial bonding strength makes interlayer micro-defects more likely, increasing the permeation channels for gas and water vapor molecules, thereby deteriorating barrier properties and hydrostatic retention, and significantly increasing the drop breakage rate.

[0077] Comparative Example 2: Hydrophobic hydrotalcite without ionic liquid intercalation was replaced with an equal mass of unmodified Mg-Al LDH, and the oxygen permeability increased from 12.2 cm⁻¹. 3 / m2 • 24h • 0.1MPa rose to 33.8cm 3 / m 2 • 24h • 0.1MPa (increase of 177.0%), water vapor transmission rate increased from 2.4g / m 2 • Increased to 5.8g / m² in 24 hours 2 • After 24 hours (an increase of 141.7%), the puncture strength decreased from 54 N to 40 N (a decrease of 25.9%), and the 30-day static pressure retention rate decreased from 95.7% to 71.8% (a decrease of 25.0%). Ionic liquid intercalation-modified hydrophobic hydrotalcite expands the interlayer spacing to 1.4–1.8 nm through ionic liquid intercalation and reduces water absorption through silane coupling agent surface modification. This allows it to form a labyrinthine gas barrier channel within the polymer matrix, while maintaining good compatibility with the matrix and providing reinforcement. Without this component, the surface is rich in hydroxyl groups, easily adsorbing water molecules. In high-humidity environments, interlayer delamination or aggregation easily occurs, failing to form an effective labyrinthine barrier structure and losing its reinforcing effect due to aggregation, resulting in a significant decrease in barrier performance and puncture strength.

[0078] Comparative Example 3: In the preparation of reactive pre-crosslinked hybrid toughening particles, bis(tert-butylperoxyisopropyl)benzene (BIPB) was not added, and step 3) was omitted. The tensile strength decreased from 43.1 MPa to 33.2 MPa (a decrease of 23.0%), the puncture strength decreased from 54 N to 38 N (a decrease of 29.6%), and the oxygen permeability decreased from 12.2 cm⁻¹. 3 / m 2 • 24h • 0.1MPa rose to 20.7cm 3 / m 2 • 24h • 0.1MPa (increase of 69.7%), 30d static pressure retention rate decreased from 95.7% to 81.9% (decrease of 14.4%), and heat seal strength decreased from 34.1N / 15mm to 23.7N / 15mm (decrease of 30.5%). The controllable pre-crosslinking step in step 3) forms a slightly crosslinked network in the EPDM rubber phase, ensuring the hybrid particles maintain a stable core-shell structure during subsequent high-temperature melt processing, preventing the nano-SiO2 shell from detaching or the particles from deforming and agglomerating. Without this step, the hybrid particles are prone to plastic deformation and agglomeration during melt extrusion, failing to maintain the preset core-shell structure. This weakens the reinforcing and toughening effect of nano-SiO2, reduces the interfacial bonding strength between the particles and the matrix, and thus significantly decreases mechanical properties, barrier properties, and heat seal performance.

[0079] Comparative Example 4: In the preparation of hydrophobic hydrotalcite modified by ionic liquid intercalation, without hydrophobic modification using the silane coupling agent KH-570, the oxygen permeability was reduced from 12.2 cm⁻¹. 3 / m 2 • 24h • 0.1MPa rose to 27.1cm 3 / m2 • 24h • 0.1MPa (increase of 122.1%), water vapor transmission rate increased from 2.4g / m 2 • Increased to 5.0g / m² in 24 hours 2 • After 24 hours (an increase of 108.3%), the 30-day hydrostatic retention rate decreased from 95.7% to 75.9% (a decrease of 20.7%). Hydrophobic modification, achieved by reacting a silane coupling agent with the hydroxyl groups on the LDH surface, reduces its surface energy and water absorption, ensuring interlayer stability under high humidity and good compatibility with the polyolefin matrix. Without this step, the LDH surface retains a large number of hydrophilic hydroxyl groups, easily adsorbing water molecules from the environment, leading to interlayer hydration swelling or peeling, and disrupting the integrity of the labyrinthine barrier structure. Simultaneously, increased water absorption makes the film prone to interlayer separation under long-term hydrostatic pressure, significantly reducing gas barrier performance and hydrostatic retention rate.

[0080] Comparative Example 5: Without the addition of maleic anhydride-grafted polyethylene (MAH-g-PE) compatibilizer, the tensile strength decreased from 43.1 MPa to 27.9 MPa (a decrease of 35.3%), the puncture strength decreased from 54 N to 30 N (a decrease of 44.4%), and the oxygen permeability decreased from 12.2 cm⁻¹. 3 / m 2 • 24h • 0.1MPa rose to 40.6cm 3 / m 2 • 24h • 0.1MPa (increase of 232.8%), water vapor transmission rate increased from 2.4g / m 2 • Increased to 7.2g / m² in 24 hours 2 • Over 24 hours (a 200% increase), the 1.2m drop failure rate increased from 0% to 42%, the 30-day static pressure retention rate decreased from 95.7% to 64.6% (a 32.5% decrease), the heat seal strength decreased from 34.1 N / 15mm to 17.3 N / 15mm (a 49.3% decrease), and the interlayer peel strength decreased from 2.4 N / 15mm to 0.8 N / 15mm (a 66.7% decrease). The anhydride groups of MAH-g-PE undergo esterification with the hydroxyl groups at the edge of the ionic liquid-intercalated modified hydrotalcite, forming ester bonds. Simultaneously, under the catalysis of dicyandiamide, they undergo ring-opening addition reactions with the epoxy groups of the reactive pre-crosslinked hybrid toughening particles, comprehensively improving the interfacial compatibility between the polar filler and the non-polar matrix. When this component is missing, the interfacial bonding between the polar filler and the non-polar polyolefin matrix is ​​severely weakened. The filler is prone to agglomeration and cannot effectively transfer stress, resulting in a significant overall decrease in mechanical properties, barrier properties and interlayer peel strength, and a significant increase in drop breakage rate.

[0081] Comparative Example 6: Without the addition of maleic anhydride-grafted polyglycerol-10 laurate, and replaced with an equal mass of metallocene linear low-density polyethylene, the initial heat-sealing temperature increased from 90℃ to 112℃ (an increase of 24.4%), the heat-sealing strength decreased from 34.1 N / 15 mm to 19.4 N / 15 mm (a decrease of 43.1%), the hot-tack strength decreased from 15.9 N / 15 mm to 6.6 N / 15 mm (a decrease of 58.5%), and the heat-sealing window narrowed from 44℃ to 18℃ (a decrease of 59.1%). Maleic anhydride-grafted polyglycerol-10 laurate exerts an internal plasticizing effect through its chemical grafting structure, moderately reducing the heat-sealing temperature, while simultaneously blocking migration to prevent surface stickiness. This component has no reinforcing or barrier functions; therefore, after replacement with metallocene linear low-density polyethylene, the mechanical and barrier properties of the film remained essentially unchanged, but the heat-sealing performance decreased significantly.

[0082] Comparative Example 7: Without the addition of ethylene-octene copolymer (POE), the film was replaced with an equal mass of metallocene linear low-density polyethylene. The elongation at break decreased from 735% to 650% (a decrease of 11.6%), and the puncture strength decreased from 54N to 48N (a decrease of 11.1%). As a polyolefin elastomer, POE synergistically enhances the film's elongation at break and low-temperature flexibility with EPDM rubber. However, its auxiliary effect on puncture strength is weak. Therefore, the absence of this component slightly reduced the film's toughness, but there was no significant deterioration in puncture strength or drop failure rate.

[0083] Comparative Example 8: Using a traditional five-layer co-extruded film structure (PE / adhesive / PA / adhesive / PE), the tensile strength decreased from 43.1 MPa to 24.5 MPa (a decrease of 43.2%), the puncture strength decreased from 54 N to 26 N (a decrease of 51.9%), and the oxygen permeability decreased from 12.2 cm⁻¹. 3 / m 2 • 24h • 0.1MPa rose to 43.6cm 3 / m 2 • 24h • 0.1MPa (increase of 257.4%), water vapor transmission rate increased from 2.4g / m 2 • Increased to 8.2g / m² in 24 hours 2 • Over 24 hours (an increase of 241.7%), the 1.2m drop breakage rate increased from 0% to 55%, the 30-day static pressure retention rate decreased from 95.7% to 57.9% (a decrease of 39.5%), the heat seal strength decreased from 34.1 N / 15mm to 14.4 N / 15mm (a decrease of 57.8%), and the interlayer peel strength decreased from 2.4 N / 15mm to 1.0 N / 15mm (a decrease of 58.3%). The interlayer bonding of traditional PE / PA five-layer co-extruded films is only the interfacial entanglement of the molecular chains of PE and PA, without chemical bonding. The interfacial bonding strength is far lower than that of the ester-bonded chemical bonding interface of this invention. Therefore, the overall mechanical properties, barrier properties, drop protection performance, and long-term static pressure retention rate are all significantly reduced.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A novel film for preparing air column bags, characterized in that, The film has an A / B / A three-layer co-extruded structure with a total thickness of 80~120μm; By weight, the raw materials for preparing layer A include: 45-55 parts linear low-density polyethylene, 8-12 parts EPDM rubber, 12-18 parts reactive pre-crosslinked hybrid toughening particles, 5-8 parts ionic liquid intercalated modified hydrophobic hydrotalcite, 3-5 parts maleic anhydride grafted polyethylene, 2-4 parts maleic anhydride grafted polyglycerol-10 laurate, 6-10 parts ethylene-octene copolymer, 0.3-0.6 parts antioxidant compound, 0.5-1.0 parts processing aid, and 0.1-0.3 parts dicyandiamide latent catalyst; The raw materials for preparing layer B, by weight, include: 60-70 parts of ethylene-vinyl alcohol copolymer, 15-20 parts of polyamide, 8-12 parts of ionic liquid intercalated modified hydrophobic hydrotalcite, 5-8 parts of maleic anhydride grafted ethylene-vinyl alcohol copolymer, and 0.2-0.4 parts of antioxidant.

2. The novel film for preparing air column bags according to claim 1, characterized in that, The linear low-density polyethylene is metallocene linear low-density polyethylene with a density of 0.912~0.918 g / cm³. 3 The melt flow index is 1.0~2.0 g / 10 min; the ethylene content in the EPDM rubber is 55~65 wt%; the grafting rate of the maleic anhydride-grafted polyethylene is 0.8~1.2%; the grafting rate of the maleic anhydride-grafted polyglycerol-10 laurate is 1.0~1.5%; the D of the dicyandiamide-based latent catalyst... 50 The particle size is ≤5μm, and the activation temperature is 160~180℃; the grafting rate of the maleic anhydride-grafted ethylene-vinyl alcohol copolymer is 0.5~0.8%.

3. The novel film for preparing air column bags according to claim 2, characterized in that, The antioxidant compound in layer A is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 to 2. The processing aid is composed of zinc stearate and fluoropolymer processing aid in a mass ratio of 1 to 2:

1. The polyamide is polyamide 6. The antioxidant in layer B is one or a combination of antioxidant 1010 and antioxidant 168.

4. The novel film for preparing air column bags according to claim 1, characterized in that, The raw materials for preparing the reactive pre-crosslinked hybrid toughening particles, by weight, include: 90-100 parts of EPDM rubber, 800-900 parts of anhydrous toluene, 10-15 parts of m-chloroperoxybenzoic acid, 8-12 parts of tetraethyl orthosilicate, 4-6 parts of deionized water, 0.5-0.8 parts of dibutyltin dilaurate, 0.3-0.6 parts of bis(tert-butylperoxyisopropyl)benzene, and 200-300 parts of methanol.

5. The novel film for preparing air column bags according to claim 4, characterized in that, The preparation method of the reactive pre-crosslinked hybrid toughening particles includes the following steps: 1) Prepare a 20-30 wt% m-chloroperoxybenzoic acid / anhydrous toluene solution by dissolving m-chloroperoxybenzoic acid in a portion of anhydrous toluene; add EPDM rubber to the remaining anhydrous toluene and stir at 300-400 r / min at 60-70℃ for 2-3 hours; add the m-chloroperoxybenzoic acid / anhydrous toluene solution dropwise at a rate of 1-2 mL / min; after the addition is complete, stir at 300-400 r / min at 70-75℃ for 3-4 hours to obtain an epoxidized EPDM rubber solution. 2) The epoxidized EPDM rubber solution was stirred at 50-60℃ and 250-350 r / min for 4-6 h. Tetraethyl orthosilicate, deionized water, and dibutyltin dilaurate were added, and the mixture was stirred at 50-60℃ and 250-350 r / min for 12-16 h to obtain an organic-inorganic hybrid system. 3) First, remove toluene from the organic-inorganic hybrid system under reduced pressure, then add bis(tert-butylperoxyisopropyl)benzene to it, transfer it to a mixer, heat it to 160~170℃, control the speed of the mixer to 80~100r / min and the filling coefficient to 0.7~0.8, and mix for 3~5min; 4) Add the material after intensive mixing in step 3) to methanol and stir at 150~200 r / min for 5~10 min. Then let it stand and settle for 1~2 h. Vacuum filter, wash the filter cake with methanol 3~4 times, place the washed solid in a vacuum drying oven and dry it at 80~90℃ and vacuum degree -0.090~-0.095MPa for 4~6 h. Crush and sieve to obtain reactive pre-crosslinked hybrid toughening particles with a particle size of 2~4 μm.

6. The novel film for preparing air column bags according to claim 1, characterized in that, The raw materials for preparing the ionic liquid intercalated modified hydrophobic hydrotalcite, by weight, include: 30-34 parts magnesium nitrate hexahydrate, 10-14 parts aluminum nitrate nonahydrate, 12-16 parts sodium hydroxide, 8-10 parts anhydrous sodium carbonate, 400-600 parts deionized water, 15-20 parts 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1-2 parts silane coupling agent KH-570, and 50-80 parts anhydrous ethanol.

7. The novel film for preparing air column bags according to claim 6, characterized in that, The preparation method of the ionic liquid intercalated modified hydrophobic hydrotalcite includes the following steps: (1) Under nitrogen protection, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate are added to a portion of deionized water at 60~70℃ to prepare a salt solution with a total metal salt concentration of 0.5~0.8mol / L; sodium hydroxide and anhydrous sodium carbonate are added to a portion of deionized water at 60~70℃ to prepare an alkaline solution with a total metal salt concentration of 1.0~1.5mol / L. Salt and alkali solutions were simultaneously added dropwise to the reaction vessel at a rate of 2-3 mL / min, maintaining the pH of the reaction system at 9.5-10.5 and the temperature at 60-70℃ for 18-24 h. After aging, the reaction solution was centrifuged at 8000-10000 r / min for 15-20 min, and the precipitate was collected. The precipitate was washed 3-4 times with deionized water until the pH of the washing solution reached 6.8-7.

2. The washed precipitate was placed in a vacuum drying oven and dried at 60-70℃ and a vacuum of -0.090 to -0.095 MPa for 12-14 h to obtain the Mg-Al LDH precursor. (2) Add the Mg-Al LDH precursor to the remaining deionized water and disperse it for 30-40 min under ultrasonic power of 300-400 W and frequency of 20-30 kHz. Then transfer it to the reaction vessel, add 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine salt, and stir the reaction at 250-350 r / min at 70-80 °C for 24-30 h. Centrifuge the reaction solution at 8000-10000 r / min for 15-20 min, collect the precipitate, wash the precipitate with deionized water 3-4 times, place the washed precipitate in a vacuum drying oven, and dry it for 10-12 h at 70-80 °C and vacuum degree of -0.090--0.095 MPa to obtain ionic liquid intercalated modified LDH. (3) Add the ionic liquid intercalated modified LDH to anhydrous ethanol and stir at 200~300 r / min for 10~15 min. Add silane coupling agent KH-570 dropwise at a rate of 0.5~1 mL / min. After the addition is complete, stir the reaction at 150~200 r / min at 60~70℃ for 4~6 h. Centrifuge the reaction solution at 8000~10000 r / min for 15~20 min, collect the precipitate, wash the precipitate with deionized water 3~4 times, place the washed precipitate in a vacuum drying oven, and dry it at 80~90℃ and vacuum degree -0.090~-0.095 MPa for 8~10 h. After cooling to 25~30℃, grind it through a 400~450 mesh sieve to obtain ionic liquid intercalated modified hydrophobic hydrotalcite.

8. The novel film for preparing air column bags according to claim 1, characterized in that, The raw materials for preparing the maleic anhydride-grafted polyglycerol-10 laurate, by weight, include: 90-100 parts of polyglycerol-10 laurate, 5-8 parts of maleic anhydride, 0.1-0.2 parts of hydroquinone, 150-200 parts of anhydrous toluene, and 100-150 parts of methanol. The preparation method of the maleic anhydride-grafted polyglycerol-10 laurate includes the following steps: a. Add polyglycerol-10 laurate and anhydrous toluene to a reaction vessel and stir at 70-80°C at 200-300 r / min for 1-2 h to dissolve. Then add maleic anhydride and hydroquinone, heat to 90-100°C, and stir at 250-350 r / min for 6-8 h. b. After the reaction is complete, cool to 40-50℃, add methanol, stir at 250-350 r / min for 1-2 h, centrifuge the reaction solution at 8000-10000 r / min for 15-20 min, collect the precipitate, wash the precipitate with deionized water 3-4 times, and then place the washed precipitate in a vacuum drying oven and dry it at 70-80℃ and a vacuum degree of -0.090 to -0.095 MPa for 6-8 h to obtain maleic anhydride-grafted polyglycerol-10 laurate.

9. A method for preparing a novel thin film for preparing an air column bag according to any one of claims 3-8, characterized in that, Includes the following steps: S1. Ingredients and Premixing: Premix each component of layer A according to the formula to obtain layer A premix, and then dry it at 70~80℃ and vacuum degree -0.090~-0.095MPa for 4~6h; after drying each component of layer B according to the formula, mix them to obtain layer B premix. S2, Melting and Plasticizing and Extrusion: The A-layer premix and the B-layer premix are added to a single screw extruder for melting and plasticizing extrusion, and the temperature, feeding speed and back pressure of each extruder are controlled. S3. Co-extrusion and blowing: The molten material of layer A and layer B obtained in step S2 are fed into a three-layer co-extrusion spiral mandrel die and extruded. After extrusion, compressed air is introduced for blowing and cooling by an air ring. The thickness ratio of layer A: layer B: layer A of the film is controlled to be 1:(1~1.5):

1. S4. Winding and post-treatment: After cooling and shaping, the film is treated with corona and then wound up. It is then cured at 23~27℃ and 45~55% relative humidity for 24~48h to obtain a new type of film for preparing air column bags.

10. The method for preparing the novel film for preparing an air column bag according to claim 9, characterized in that, In step S1, the premixing process of each component in layer A is as follows: linear low-density polyethylene, EPDM rubber, reactive pre-crosslinked hybrid toughening particles, ionic liquid intercalated modified hydrophobic hydrotalcite, maleic anhydride grafted polyethylene, ethylene-octene copolymer, antioxidant compound, processing aid, and dicyandiamide latent catalyst are added to a high-speed mixer and mixed at 800-1000 r / min at 40-50°C for 8-12 min. Then, maleic anhydride grafted polyglycerol-10 laurate is added, and mixing continues for 2-3 min. The premixing process of each component in layer B is as follows: Ethylene-vinyl alcohol copolymer, polyamide 6, ionic liquid intercalated modified hydrophobic hydrotalcite, maleic anhydride grafted ethylene-vinyl alcohol copolymer, and antioxidant are added sequentially to a vacuum drying oven and dried at 80~90℃ and vacuum degree -0.090~-0.095MPa for 4~6 hours. After drying, the material is transferred to a high-speed mixer and mixed at 30~40℃ and a speed of 600~800r / min for 5~8 minutes. In step S2, the screw diameter of the A-layer extruder is 60~70mm, the length-to-diameter ratio is 28~32:1, the compression ratio is 2.3~2.7:1; the feeding section is 150~160℃, the compression section is 170~180℃, the metering section is 185~195℃, the die head is 190~200℃, the screw speed is 40~60r / min, and the back pressure is 0.3~0.5MPa. The B-layer extruder uses a barrier screw with a diameter of 50-60mm, a length-to-diameter ratio of 30-35:1, and a compression ratio of 3.0-3.5:

1. The feeding section has a temperature of 180-190℃, the compression section 200-210℃, the metering section 220-230℃, and the die head 225-235℃. The screw speed is 30-50 r / min, and the back pressure is 0.4-0.6 MPa. In step S3, the die diameter of the three-layer co-extrusion spiral mandrel die is 50~60mm, the die gap is 0.8~1.2mm, and the die temperature is 220~230℃; the blow-up ratio is 2.0~2.5, the draw ratio is 2.5~3.5; the air ring diameter is 80~120mm, the cooling air temperature is 20~25℃, and the condensation line height is 200~300mm. In step S4, the corona power during corona treatment is 300~400W, and the treatment speed is 15~25m / min; the winding tension during winding is 20~30N, and the winding speed is 15~25m / min.

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