High-barrier anti-wrinkle aviation isolating membrane and preparation method thereof

Abstract

The invention discloses a high-barrier anti-wrinkle aviation isolating membrane and a preparation method thereof, and relates to the technical field of membrane materials, the high-barrier anti-wrinkle aviation isolating membrane comprises a base membrane layer and a functional protective layer coated on the outer surface of the base membrane layer; the base film layer sequentially comprises an anti-wrinkle layer, a barrier layer and a base material layer from top to bottom; the barrier layer is prepared from the following raw materials in parts by weight: 70 to 80 parts of ethylene-vinyl alcohol copolymer, 0.5 to 1 part of MXene nanosheet and 15 to 25 parts of starch nanocrystal; the anti-wrinkle layer is prepared from the following raw materials in parts by weight: 100 parts of PVDF (Polyvinylidene Fluoride) resin, 10 to 20 parts of maleic anhydride grafted ethylene-octylene copolymer and 10 to 20 parts of fluorosilicone type thermoplastic polyurethane elastomer. The film is good in mechanical property, barrier property and wrinkle resistance and excellent in weather resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane materials, in particular to a high-barrier and wrinkle-resistant aviation isolation film and a preparation method thereof. Background Art

[0002] In the aviation field, isolation membranes, as key functional materials, are widely used in important scenarios such as aviation fuel storage and cabin environment isolation. However, existing aviation isolation membranes face many challenges in practical applications. On the one hand, with the rapid development of the aviation industry, higher requirements are placed on the barrier properties of isolation membranes. The barrier effect of traditional isolation membranes on oxygen, moisture and small molecular pollutants can no longer meet the harsh operating environment of modern aviation. This may lead to problems such as fuel oxidation and deterioration, equipment damage due to moisture, etc., seriously affecting aviation safety and equipment service life. On the other hand, aviation equipment will experience complex mechanical environments and temperature changes during operation. The wrinkle resistance of traditional isolation membranes is insufficient and they are prone to wrinkling or even rupture under stress. The generation of wrinkles will not only reduce the barrier properties of the isolation membrane, but may also cause local stress concentration, further accelerating the damage of the membrane material, increasing aviation maintenance costs and safety hazards.

[0003] Commercial aviation barrier films still have technical drawbacks, such as insufficient weather resistance, complex manufacturing processes, high production costs, and the need to further improve barrier and wrinkle resistance. To address these issues, a Chinese invention patent, authorized with publication number CN116476496B, discloses a high-barrier, wrinkle-resistant PP barrier film, which comprises, from top to bottom, a protective layer, a reinforcement layer, a barrier layer, a reinforcement layer, a protective layer, and a silicone oil layer. The protective layer comprises the following raw materials in parts by weight: 56-57 parts nylon 6, 17-18 parts ethylene-acrylic acid copolymer, 2-3 parts talc, 0.3-0.4 parts antioxidant 2246, 0.1-0.2 parts antioxidant 168, and 0.2-0. The reinforcing layer comprises the following raw materials by weight: 56-57 parts nylon 6, 24-25 parts nylon 66, 0.3-0.4 parts antioxidant 2246, and 0.2-0.3 parts silicone. The barrier layer is modified polyethylene. The base film is produced through a five-layer co-extrusion process. The base film is plasma treated and then coated with a modified silicone oil and UV-cured to form a silicone oil layer. This improves the film's yield strength, tensile strength, and surface strength, and enhances its flexural properties, stress cracking resistance, and abrasion resistance. However, the barrier properties, wrinkle resistance, and weather resistance of this isolation film still need to be further improved.

[0004] It can be seen that developing a high-barrier and wrinkle-resistant aviation isolation film with good mechanical properties, excellent barrier properties and wrinkle-resistant properties, and excellent weather resistance and a preparation method thereof is a difficult problem that needs to be solved urgently in the industry. Summary of the Invention

[0005] The main purpose of the present invention is to provide a high-barrier and wrinkle-resistant aviation isolation film with good mechanical properties, good barrier properties and wrinkle-resistant properties, and excellent weather resistance, and a preparation method thereof.

[0006] To achieve the above objectives, the present invention provides a high-barrier, wrinkle-resistant aviation isolation film, comprising a base film layer and a functional protective layer coated on the outer surface of the base film layer; the base film layer comprises, from top to bottom, an anti-wrinkle layer, a barrier layer, and a substrate layer; the barrier layer comprises the following raw materials in parts by weight: 70-80 parts of ethylene-vinyl alcohol copolymer, 0.5-1 part of MXene nanosheets, and 15-25 parts of starch nanocrystals; the anti-wrinkle layer comprises the following raw materials in parts by weight: 100 parts of PVDF resin, 10-20 parts of maleic anhydride grafted ethylene-octene copolymer, and 10-20 parts of fluorosilicone thermoplastic polyurethane elastomer.

[0007] Preferably, the thickness of the functional protective layer is 5-10 μm; the thickness of the substrate layer is 40-60 μm; the thickness of the barrier layer is 15-25 μm; and the thickness of the anti-wrinkle layer is 10-20 μm.

[0008] Preferably, the raw material of the substrate layer is PVDF resin.

[0009] Preferably, the ethylene-vinyl alcohol copolymer is Soarnol™ DC3212B EVOH produced by Mitsubishi Chemical.

[0010] Preferably, the MXene nanosheets are titanium carbide MXene multilayer nanosheets with a thickness of 100-200 nm and a sheet diameter of 2-10 μm.

[0011] Preferably, the starch nanocrystals have a diameter of 10-100 nm and a length of 50-500 nm.

[0012] Preferably, the PVDF resin is Solef® 11010 PVDF.

[0013] Preferably, the maleic anhydride grafted ethylene-octene copolymer is AMPLIFY GR216 developed and produced by Dow Chemical Company of the United States.

[0014] Preferably, there is no special requirement for the source of the fluorosilicone thermoplastic polyurethane elastomer. In one embodiment of the present invention, the fluorosilicone thermoplastic polyurethane elastomer is made according to the method of Example 6 of the Chinese invention patent with authorization publication number CN111154064B.

[0015] Preferably, the functional protective layer is made of the following raw materials in parts by weight: 1-3 parts of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3-5 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 3-5 parts of 1,4-diacryloyl-1,2,3,4-tetrahydro-6,7-dimethylquinoxaline, and 1-3 parts of 2,4,6-trivinylcycloboroxane.

[0016] Another object of the present invention is to provide a method for preparing the high-barrier, wrinkle-resistant aviation isolation film, comprising the following steps: Step S1, preparing a barrier layer masterbatch: adding the raw materials of the barrier layer according to parts by weight into a twin-screw extruder, extruding at a temperature of 180-200° C. and a screw speed of 200-250 r / min, and blending, extruding and granulating to obtain a barrier layer masterbatch; Step S2, preparation of anti-wrinkle layer masterbatch: adding the raw materials of the anti-wrinkle layer according to weight into a twin-screw extruder, extruding at a temperature of 170-190° C. and a screw speed of 180-220 r / min, blending, extruding and granulating to obtain the anti-wrinkle layer masterbatch; Step S3, film casting: using a multi-layer co-extrusion casting process, the base material PVDF, the barrier layer masterbatch and the anti-wrinkle layer masterbatch are added to different extruders respectively, and co-extruded through the die head to form a film; Step S4, biaxial stretching: biaxially stretching the film obtained by casting, heat-setting it, and then cooling it to room temperature to obtain a primary film; Step S5, radiation grafting: After uniformly mixing the raw materials of the functional protective layer by weight, a mixed raw material is obtained, the mixed raw material is dispersed in tetrahydrofuran to obtain a dispersion, and the dispersion is uniformly coated on the surface of the primary film. The film is irradiated under an electron beam in a nitrogen atmosphere and then placed at 95-105° C. for 3-5 hours to obtain a high-barrier and wrinkle-resistant aviation isolation film.

[0017] Preferably, the extrusion temperatures of the co-extrusion cast film layers in step S3 are: 180-200° C. for the substrate layer, 200-210° C. for the barrier layer, and 180-190° C. for the anti-wrinkle layer.

[0018] Preferably, the temperature of the biaxial stretching in step S4 is 110-120° C., and the stretching ratio is 3-5 times.

[0019] Preferably, the heat setting temperature in step S4 is 165-175° C., and the holding time is 10-30 seconds.

[0020] Preferably, the mass ratio of the mixed raw material and tetrahydrofuran in step S5 is (8-12):100.

[0021] Preferably, the radiation in step S5 is carried out at room temperature and is continuous electron beam radiation with an absorbed dose of 100-400 kGy, a beam current of 25-110 mA, a voltage of 300-500 kV, and a radiation dose rate of 8-12 kGy / h.

[0022] Due to the application of the above technical solution, the present invention has the following beneficial effects: (1) The method for preparing the high-barrier, wrinkle-resistant aviation isolation film disclosed in the present invention has a simple preparation process, convenient operation and control, does not require special equipment, and does not require modification of the original production line. It has high preparation efficiency and finished product qualification rate, is suitable for continuous large-scale production, and has high promotion and application value.

[0023] (2) The high-barrier, wrinkle-resistant aviation isolation film disclosed in the present invention comprises a base film layer and a functional protective layer coated on the outer surface of the base film layer; the base film layer comprises, from top to bottom, an anti-wrinkle layer, a barrier layer, and a substrate layer; the barrier layer comprises the following raw materials in parts by weight: 70-80 parts of ethylene-vinyl alcohol copolymer, 0.5-1 parts of MXene nanosheets, and 15-25 parts of starch nanocrystals; the anti-wrinkle layer comprises the following raw materials in parts by weight: 100 parts of PVDF resin, 10-20 parts of maleic anhydride-grafted ethylene-octene copolymer, and 10-20 parts of fluorosilicone thermoplastic polyurethane elastomer. By rationally selecting the structure and the raw material formula of each layer, the isolation film has good mechanical properties, excellent barrier and anti-wrinkle properties, and excellent weather resistance. In terms of high barrier performance, the barrier layer is formed by combining ethylene-vinyl alcohol copolymer with MXene nanosheets and starch nanocrystals. While ethylene-vinyl alcohol copolymer itself has excellent gas barrier properties, the addition of MXene nanosheets and starch nanocrystals creates a "maze effect," increasing the diffusion paths for gases and water vapor, significantly improving the barrier performance of the separator. The introduction of two-dimensional MXene nanosheets into the system further enhances the barrier performance by cross-linking with PVOH through hydrogen bonds to form a "nano-brick wall" structure.

[0024] (3) The high barrier and wrinkle-resistant aviation isolation film disclosed in the present invention has anti-wrinkle performance. Maleic anhydride grafted ethylene-octene copolymer and fluorosilicone thermoplastic polyurethane elastomer are added to the anti-wrinkle layer. They have good compatibility with PVDF and can form an elastic network structure in the PVDF matrix to effectively absorb and disperse stress, thereby improving the anti-wrinkle performance and flexibility of the isolation film.

[0025] (4) The high-barrier, wrinkle-resistant aviation isolation film disclosed in the present invention, wherein the functional protective layer is made of the following raw materials in parts by weight: 1-3 parts of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3-5 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 3-5 parts of 1,4-diacryloyl-1,2,3,4-tetrahydro-6,7-dimethylquinoxaline, and 1-3 parts of 2,4,6-trivinylcycloboroxine. The fluorinated propane, triazine, quinoxaline, and cycloboroxine structures introduced simultaneously can effectively improve the mechanical properties, barrier properties, and weather resistance of the isolation film under the multiple effects of electronic effect, steric effect, and conjugation effect. Through radiation grafting, an interpenetrating network structure is formed on the outer surface of the film, further improving the above-mentioned properties.

[0026] (5) The high barrier and wrinkle-resistant aviation isolation film disclosed in the present invention has good processing performance, sufficient mechanical properties, good barrier properties and wrinkle-resistant properties, and excellent weather resistance through the reasonable selection of preparation process parameters. DETAILED DESCRIPTION

[0027] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations. Example 1

[0028] A high-barrier, wrinkle-resistant aviation isolation film comprises a base film layer and a functional protective layer coated on the outer surface of the base film layer; the base film layer comprises, from top to bottom, an anti-wrinkle layer, a barrier layer, and a substrate layer; the barrier layer comprises the following raw materials in parts by weight: 70 parts of ethylene-vinyl alcohol copolymer, 0.5 parts of MXene nanosheets, and 15 parts of starch nanocrystals; the anti-wrinkle layer comprises the following raw materials in parts by weight: 100 parts of PVDF resin, 10 parts of maleic anhydride-grafted ethylene-octene copolymer, and 10 parts of fluorosilicone thermoplastic polyurethane elastomer.

[0029] The thickness of the functional protective layer is 5 μm; the thickness of the substrate layer is 40 μm; the thickness of the barrier layer is 15 μm; the thickness of the anti-wrinkle layer is 10 μm; the raw material of the substrate layer is PVDF resin; the ethylene-vinyl alcohol copolymer is Soarnol™ DC3212B EVOH produced by Mitsubishi Chemical; the MXene nanosheets are titanium carbide MXene multilayer nanosheets with a thickness of 100-200 nm and a sheet diameter of 2-10 μm; the diameter of the starch nanocrystals is 10-100 nm and the length is 50-500 nm; the PVDF resin is Solef® 11010 PVDF; the maleic anhydride grafted ethylene-octene copolymer is AMPLIFY GR216 developed and produced by Dow Chemical Company of the United States; and the fluorosilicone thermoplastic polyurethane elastomer is prepared according to the method of Example 6 of the Chinese invention patent with authorization publication number CN111154064B.

[0030] The functional protective layer is made of the following raw materials in parts by weight: 1 part of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 3 parts of 1,4-diacryloyl-1,2,3,4-tetrahydro-6,7-dimethylquinoxaline, and 1 part of 2,4,6-trivinylcycloboroxane.

[0031] A method for preparing the high-barrier, wrinkle-resistant aviation isolation film comprises the following steps: Step S1, preparing a barrier layer masterbatch: adding the raw materials of the barrier layer according to parts by weight into a twin-screw extruder, extruding at an extrusion temperature of 180° C. and a screw speed of 200 r / min, and blending, extruding and granulating to obtain a barrier layer masterbatch; Step S2, preparation of anti-wrinkle layer masterbatch: adding the raw materials of the anti-wrinkle layer according to weight into a twin-screw extruder, extruding at an extrusion temperature of 170° C. and a screw speed of 180 r / min, and blending, extruding and granulating to obtain the anti-wrinkle layer masterbatch; Step S3, film casting: using a multi-layer co-extrusion casting process, the base material PVDF, the barrier layer masterbatch and the anti-wrinkle layer masterbatch are added to different extruders respectively, and co-extruded through the die head to form a film; Step S4, biaxial stretching: biaxially stretching the film obtained by casting, heat-setting it, and then cooling it to room temperature to obtain a primary film; Step S5, radiation grafting: After uniformly mixing the raw materials of the functional protective layer according to parts by weight to obtain a mixed raw material, the mixed raw material is dispersed in tetrahydrofuran to obtain a dispersion, which is uniformly coated on the surface of the primary film, and irradiated under an electron beam in a nitrogen atmosphere, and then placed at 95° C. for 3 hours to obtain a high-barrier and wrinkle-resistant aviation isolation film.

[0032] The extrusion temperatures of each layer of the co-extrusion cast film in step S3 are: 180°C for the substrate layer, 200°C for the barrier layer, and 180°C for the anti-wrinkle layer; the temperature of the biaxial stretching in step S4 is 110°C, and the stretching ratio is 4 times; the heat setting temperature in step S4 is 165°C, and the holding time is 10s; the mass ratio of the mixed raw material and tetrahydrofuran in step S5 is 8:100; the irradiation in step S5 is carried out at room temperature, is continuous electron beam irradiation, has an absorbed dose of 100 kGy, a beam current of 25 mA, a voltage of 300 kV, and a radiation dose rate of 8 kGy / h. Example 2

[0033] A high-barrier, wrinkle-resistant aviation isolation film comprises a base film layer and a functional protective layer coated on the outer surface of the base film layer; the base film layer comprises, from top to bottom, an anti-wrinkle layer, a barrier layer, and a substrate layer; the barrier layer comprises the following raw materials in parts by weight: 73 parts of ethylene-vinyl alcohol copolymer, 0.6 parts of MXene nanosheets, and 17 parts of starch nanocrystals; the anti-wrinkle layer comprises the following raw materials in parts by weight: 100 parts of PVDF resin, 13 parts of maleic anhydride-grafted ethylene-octene copolymer, and 13 parts of fluorosilicone thermoplastic polyurethane elastomer.

[0034] The thickness of the functional protective layer is 5 μm; the thickness of the substrate layer is 40 μm; the thickness of the barrier layer is 15 μm; the thickness of the anti-wrinkle layer is 10 μm; the raw material of the substrate layer is PVDF resin; the ethylene-vinyl alcohol copolymer is Soarnol™ DC3212B EVOH produced by Mitsubishi Chemical; the MXene nanosheets are titanium carbide MXene multilayer nanosheets with a thickness of 100-200 nm and a sheet diameter of 2-10 μm; the diameter of the starch nanocrystals is 10-100 nm and the length is 50-500 nm; the PVDF resin is Solef® 11010 PVDF; the maleic anhydride grafted ethylene-octene copolymer is AMPLIFY GR216 developed and produced by Dow Chemical Company of the United States; and the fluorosilicone thermoplastic polyurethane elastomer is prepared according to the method of Example 6 of the Chinese invention patent with authorization publication number CN111154064B.

[0035] The functional protective layer is made of the following raw materials in parts by weight: 1.5 parts of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3.5 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 3.5 parts of 1,4-diacryloyl-1,2,3,4-tetrahydro-6,7-dimethylquinoxaline, and 1.5 parts of 2,4,6-trivinylcycloboroxane.

[0036] A method for preparing the high-barrier, wrinkle-resistant aviation isolation film comprises the following steps: Step S1, preparing a barrier layer masterbatch: adding the raw materials of the barrier layer according to parts by weight into a twin-screw extruder, extruding at an extrusion temperature of 185° C. and a screw speed of 220 r / min, and blending, extruding and granulating to obtain a barrier layer masterbatch; Step S2, preparation of anti-wrinkle layer masterbatch: adding the raw materials of the anti-wrinkle layer according to weight into a twin-screw extruder, extruding at an extrusion temperature of 175° C. and a screw speed of 190 r / min, and blending, extruding and granulating to obtain the anti-wrinkle layer masterbatch; Step S3, film casting: using a multi-layer co-extrusion casting process, the base material PVDF, the barrier layer masterbatch and the anti-wrinkle layer masterbatch are added to different extruders respectively, and co-extruded through the die head to form a film; Step S4, biaxial stretching: biaxially stretching the film obtained by casting, heat-setting it, and then cooling it to room temperature to obtain a primary film; Step S5, radiation grafting: After uniformly mixing the raw materials of the functional protective layer according to parts by weight to obtain a mixed raw material, the mixed raw material is dispersed in tetrahydrofuran to obtain a dispersion, which is evenly coated on the surface of the primary film, and irradiated under an electron beam in a nitrogen atmosphere, and then placed at 98° C. for 3.5 hours to obtain a high-barrier and wrinkle-resistant aviation isolation film.

[0037] The extrusion temperatures of each layer of the co-extrusion cast film in step S3 are: 185°C for the substrate layer, 203°C for the barrier layer, and 183°C for the anti-wrinkle layer; the temperature of the biaxial stretching in step S4 is 113°C, and the stretching ratio is 4 times; the heat setting temperature in step S4 is 167°C, and the holding time is 15s; the mass ratio of the mixed raw material and tetrahydrofuran in step S5 is 9:100; the irradiation in step S5 is carried out at room temperature, is continuous electron beam irradiation, has an absorbed dose of 200kGy, a beam current of 40mA, a voltage of 350kV, and a radiation dose rate of 9kGy / h. Example 3

[0038] A high-barrier, wrinkle-resistant aviation isolation film comprises a base film layer and a functional protective layer coated on the outer surface of the base film layer; the base film layer comprises, from top to bottom, an anti-wrinkle layer, a barrier layer, and a substrate layer; the barrier layer comprises the following raw materials in parts by weight: 75 parts of ethylene-vinyl alcohol copolymer, 0.8 parts of MXene nanosheets, and 20 parts of starch nanocrystals; the anti-wrinkle layer comprises the following raw materials in parts by weight: 100 parts of PVDF resin, 15 parts of maleic anhydride-grafted ethylene-octene copolymer, and 15 parts of fluorosilicone thermoplastic polyurethane elastomer.

[0039] The thickness of the functional protective layer is 5 μm; the thickness of the substrate layer is 40 μm; the thickness of the barrier layer is 15 μm; the thickness of the anti-wrinkle layer is 10 μm; the raw material of the substrate layer is PVDF resin; the ethylene-vinyl alcohol copolymer is Soarnol™ DC3212B EVOH produced by Mitsubishi Chemical; the MXene nanosheets are titanium carbide MXene multilayer nanosheets with a thickness of 100-200 nm and a sheet diameter of 2-10 μm; the diameter of the starch nanocrystals is 10-100 nm and the length is 50-500 nm; the PVDF resin is Solef® 11010 PVDF; the maleic anhydride grafted ethylene-octene copolymer is AMPLIFY GR216 developed and produced by Dow Chemical Company of the United States; and the fluorosilicone thermoplastic polyurethane elastomer is prepared according to the method of Example 6 of the Chinese invention patent with authorization publication number CN111154064B.

[0040] The functional protective layer is made of the following raw materials in parts by weight: 2 parts of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 4 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 4 parts of 1,4-diacryloyl-1,2,3,4-tetrahydro-6,7-dimethylquinoxaline, and 2 parts of 2,4,6-trivinylcycloboroxane.

[0041] A method for preparing the high-barrier, wrinkle-resistant aviation isolation film comprises the following steps: Step S1, preparation of barrier layer masterbatch: adding the raw materials of the barrier layer according to parts by weight into a twin-screw extruder, extruding at an extrusion temperature of 190° C. and a screw speed of 230 r / min, and blending, extruding and granulating to obtain a barrier layer masterbatch; Step S2, preparation of anti-wrinkle layer masterbatch: adding the raw materials of the anti-wrinkle layer according to weight into a twin-screw extruder, extruding at an extrusion temperature of 180° C. and a screw speed of 200 r / min, and blending, extruding and granulating to obtain the anti-wrinkle layer masterbatch; Step S3, film casting: using a multi-layer co-extrusion casting process, the base material PVDF, the barrier layer masterbatch and the anti-wrinkle layer masterbatch are added to different extruders respectively, and co-extruded through the die head to form a film; Step S4, biaxial stretching: biaxially stretching the film obtained by casting, heat-setting it, and then cooling it to room temperature to obtain a primary film; Step S5, radiation grafting: After uniformly mixing the raw materials of the functional protective layer according to parts by weight to obtain a mixed raw material, the mixed raw material is dispersed in tetrahydrofuran to obtain a dispersion, which is uniformly coated on the surface of the primary film, and irradiated under an electron beam in a nitrogen atmosphere, and then placed at 100° C. for 4 hours to obtain a high-barrier and wrinkle-resistant aviation isolation film.

[0042] The extrusion temperatures of each layer of the co-extrusion cast film in step S3 are: 190°C for the substrate layer, 205°C for the barrier layer, and 185°C for the anti-wrinkle layer; the temperature of the biaxial stretching in step S4 is 115°C, and the stretching ratio is 4 times; the heat setting temperature in step S4 is 170°C, and the holding time is 20s; the mass ratio of the mixed raw material and tetrahydrofuran in step S5 is 10:100; the irradiation in step S5 is carried out at room temperature, is continuous electron beam irradiation, has an absorbed dose of 250kGy, a beam current of 80mA, a voltage of 400kV, and a radiation dose rate of 10kGy / h. Example 4

[0043] A high-barrier, wrinkle-resistant aviation isolation film comprises a base film layer and a functional protective layer coated on the outer surface of the base film layer; the base film layer comprises, from top to bottom, an anti-wrinkle layer, a barrier layer, and a substrate layer; the barrier layer comprises the following raw materials in parts by weight: 78 parts of ethylene-vinyl alcohol copolymer, 0.9 parts of MXene nanosheets, and 23 parts of starch nanocrystals; the anti-wrinkle layer comprises the following raw materials in parts by weight: 100 parts of PVDF resin, 19 parts of maleic anhydride-grafted ethylene-octene copolymer, and 18 parts of fluorosilicone thermoplastic polyurethane elastomer.

[0044] The thickness of the functional protective layer is 5 μm; the thickness of the substrate layer is 40 μm; the thickness of the barrier layer is 15 μm; the thickness of the anti-wrinkle layer is 10 μm; the raw material of the substrate layer is PVDF resin; the ethylene-vinyl alcohol copolymer is SoarnolTM DC3212B EVOH produced by Mitsubishi Chemical; the MXene nanosheets are titanium carbide MXene multilayer nanosheets with a thickness of 100-200 nm and a sheet diameter of 2-10 μm; the diameter of the starch nanocrystals is 10-100 nm and the length is 50-500 nm; the PVDF resin is Solef® 11010 PVDF; the maleic anhydride grafted ethylene-octene copolymer is AMPLIFY GR21 developed and produced by Dow Chemical Company of the United States; and the fluorosilicone thermoplastic polyurethane elastomer is prepared according to the method of Example 6 of the Chinese invention patent with authorization publication number CN111154064B.

[0045] The functional protective layer is made of the following raw materials in parts by weight: 2.5 parts of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 4.5 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 4.5 parts of 1,4-diacryloyl-1,2,3,4-tetrahydro-6,7-dimethylquinoxaline, and 2.5 parts of 2,4,6-trivinylcycloboroxane.

[0046] A method for preparing the high-barrier, wrinkle-resistant aviation isolation film comprises the following steps: Step S1, barrier layer masterbatch preparation: add each raw material of the barrier layer into a double screw extruder according to the weight fraction, the extrusion temperature is 195℃, the screw rotation speed is 240r / min, blend extrusion granulation is carried out, and the barrier layer masterbatch is obtained; Step S2, anti-wrinkle layer masterbatch preparation: add each raw material of the anti-wrinkle layer into a double screw extruder according to the weight fraction, the extrusion temperature is 185℃, the screw rotation speed is 210r / min, blend extrusion granulation is carried out, and the anti-wrinkle layer masterbatch is obtained; Step S3, casting film forming: the base layer raw material PVDF, the barrier layer masterbatch and the anti-wrinkle layer masterbatch are added into different extruders respectively by using a multi-layer co-extrusion casting process, and the film is formed by co-extrusion casting through a die; Step S4, biaxial stretching: the film obtained by casting is subjected to biaxial stretching treatment, and after heat setting treatment, it is cooled to room temperature to obtain a nascent film; Step S5, radiation grafting: the functional protective layer raw materials are uniformly mixed according to the weight fraction to obtain a mixed raw material, the mixed raw material is dispersed in tetrahydrofuran to obtain a dispersion liquid, the dispersion liquid is uniformly coated on the surface of the nascent film, and the film is subjected to radiation treatment under nitrogen atmosphere and electron beam, and then is placed at 103℃ for 4.5h to obtain a high-barrier anti-wrinkle aviation isolation film.

[0047] In step S3, the extrusion temperatures of each layer of the co-extrusion casting film are as follows: the base layer is 195℃, the barrier layer is 208℃, and the anti-wrinkle layer is 188℃; in step S4, the biaxial stretching temperature is 118℃, and the stretching multiple is 4 times; in step S4, the heat setting temperature is 173℃, and the heat preservation time is 25s; in step S5, the mass ratio of the mixed raw material to tetrahydrofuran is 11:100; in step S5, the radiation is carried out at room temperature, and is continuous electron beam radiation, the absorbed dose is 350kGy, the beam current is 100mA, the voltage is 450kV, and the radiation dose rate is 11kGy / h. Example 5

[0048] A high-barrier anti-wrinkle aviation isolation film, comprising a base film layer and a functional protective layer coated on the outer surface of the base film layer; the base film layer comprises an anti-wrinkle layer, a barrier layer and a base material layer from top to bottom; the barrier layer comprises the following raw materials by weight: ethylene-vinyl alcohol copolymer 80 parts, MXene nanosheet 1 part and starch nanocrystal 25 parts; the anti-wrinkle layer comprises the following raw materials by weight: PVDF resin 100 parts, maleic anhydride grafted ethylene-octene copolymer 20 parts and fluorosilicon type thermoplastic polyurethane elastomer 20 parts.

[0049] The thickness of the functional protective layer is 5 μm; the thickness of the substrate layer is 40 μm; the thickness of the barrier layer is 15 μm; the thickness of the anti-wrinkle layer is 10 μm; the raw material of the substrate layer is PVDF resin; the ethylene-vinyl alcohol copolymer is Soarnol™ DC3212B EVOH produced by Mitsubishi Chemical; the MXene nanosheets are titanium carbide MXene multilayer nanosheets with a thickness of 100-200 nm and a sheet diameter of 2-10 μm; the diameter of the starch nanocrystals is 10-100 nm and the length is 50-500 nm; the PVDF resin is Solef® 11010 PVDF; the maleic anhydride grafted ethylene-octene copolymer is AMPLIFY GR216 developed and produced by Dow Chemical Company of the United States; and the fluorosilicone thermoplastic polyurethane elastomer is prepared according to the method of Example 6 of the Chinese invention patent with authorization publication number CN111154064B.

[0050] The functional protective layer is made of the following raw materials in parts by weight: 3 parts of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 5 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 5 parts of 1,4-diacryloyl-1,2,3,4-tetrahydro-6,7-dimethylquinoxaline, and 3 parts of 2,4,6-trivinylcycloboroxane.

[0051] A method for preparing the high-barrier, wrinkle-resistant aviation isolation film comprises the following steps: Step S1, preparing a barrier layer masterbatch: adding the raw materials of the barrier layer according to parts by weight into a twin-screw extruder, extruding at a temperature of 200° C. and a screw speed of 250 r / min, and blending, extruding and granulating to obtain a barrier layer masterbatch; Step S2, preparation of anti-wrinkle layer masterbatch: adding the raw materials of the anti-wrinkle layer according to weight into a twin-screw extruder, extruding at an extrusion temperature of 190° C. and a screw speed of 220 r / min, and blending, extruding and granulating to obtain the anti-wrinkle layer masterbatch; Step S3, film casting: using a multi-layer co-extrusion casting process, the base material PVDF, the barrier layer masterbatch and the anti-wrinkle layer masterbatch are added to different extruders respectively, and co-extruded through the die head to form a film; Step S4, biaxial stretching: biaxially stretching the film obtained by casting, heat-setting it, and then cooling it to room temperature to obtain a primary film; Step S5, radiation grafting: After uniformly mixing the raw materials of the functional protective layer according to parts by weight to obtain a mixed raw material, the mixed raw material is dispersed in tetrahydrofuran to obtain a dispersion, which is uniformly coated on the surface of the primary film, and irradiated under an electron beam in a nitrogen atmosphere, and then placed at 105° C. for 5 hours to obtain a high-barrier and wrinkle-resistant aviation isolation film.

[0052] The extrusion temperatures of each layer of the co-extrusion cast film in step S3 are: 200°C for the substrate layer, 210°C for the barrier layer, and 190°C for the anti-wrinkle layer; the temperature of the biaxial stretching in step S4 is 120°C, and the stretching ratio is 4 times; the heat setting temperature in step S4 is 175°C, and the holding time is 30s; the mass ratio of the mixed raw material and tetrahydrofuran in step S5 is 12:100; the irradiation in step S5 is carried out at room temperature, is continuous electron beam irradiation, has an absorbed dose of 400kGy, a beam current of 110mA, a voltage of 500kV, and a radiation dose rate of 12kGy / h.

[0053] Comparative Example 1 A high-barrier, wrinkle-resistant aviation isolation film and a preparation method thereof, which are basically the same as Example 1, except that an equal amount of maleic anhydride-grafted ethylene-octene copolymer is used instead of a fluorosilicone-type thermoplastic polyurethane elastomer; and no MXene nanosheets are added.

[0054] Comparative Example 2 A high-barrier, wrinkle-resistant aviation isolation film and a preparation method thereof, which are substantially the same as those in Example 1, except that an equal amount of MXene nanosheets is used instead of starch nanocrystals; and 1,4-diacryloyl-1,2,3,4-tetrahydro-6,7-dimethylquinoxaline is not added.

[0055] To further illustrate the beneficial technical effects of the high-barrier, anti-wrinkle aviation isolation films involved in various embodiments of the present invention, relevant performance tests were conducted on the high-barrier, anti-wrinkle aviation isolation films involved in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1. The test methods are as follows: (1) Tensile properties: Tensile strength test is carried out according to GB / T1040.1-2018; (2) Anti-wrinkle performance test: Using the bending test method, the sample was made into a 100 mm × 50 mm specimen, fixed on a bending tester, and bent at a speed of 10 mm / min. The number of bends when the sample showed obvious wrinkles was recorded; (3) Gas barrier property: The oxygen permeability was determined by referring to GB / T 19789-2021 “Plastic film and sheeting for packaging materials - Oxidation permeability test - Coulometric method”. The test conditions were a temperature of 23°C and a relative humidity of 50%.

[0056] (4) Weather resistance: Each product was placed at 85°C × 85% RH for a test period of 168 hours. After being taken out and cooled to room temperature, the tensile strength after the test was measured. The retention rate of tensile strength was used as the measure. The larger the value, the better the weather resistance. The retention rate of tensile strength = tensile strength after the test / tensile strength before the test × 100%. The tests of tensile strength after the test and tensile strength before the test were both carried out in accordance with GB / T 1040.1-2018.

[0057] As can be seen from Table 1, the high-barrier, wrinkle-resistant aviation isolation film disclosed in the embodiments of the present invention has better tensile properties, weather resistance, wrinkle resistance, and gas barrier properties than the comparative example products. The combined use of fluorosilicone thermoplastic polyurethane elastomer, MXene nanosheets, starch nanocrystals, and 1,4-diacryloyl-1,2,3,4-tetrahydro-6,7-dimethylquinoxaline is beneficial for improving the above-mentioned properties.

[0058] Table 1 Performance test results of high barrier and anti-wrinkle aviation isolation film project tensile strength Anti-wrinkle bending times Gas barrier properties Weather resistance unit MPa Second-rate cm³ / (m²・24h・0.1MPa) % Example 1 93 1820 1.5 99.83 Example 2 96 1850 1.2 99.90 Example 3 98 1865 1.0 99.93 Example 4 99 1874 0.8 99.94 Example 5 104 1880 0.7 99.99 Comparative Example 1 87 1740 3.2 97.67 Comparative Example 2 82 1800 4.0 96.99 The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A high barrier and wrinkle-resistant aviation isolation film, characterized in that: It includes a base film layer and a functional protective layer coated on the outer surface of the base film layer; the base film layer includes an anti-wrinkle layer, a barrier layer, and a substrate layer from top to bottom; the barrier layer includes the following raw materials in parts by weight: 70-80 parts of ethylene-vinyl alcohol copolymer, 0.5-1 part of MXene nanosheets, and 15-25 parts of starch nanocrystals; the anti-wrinkle layer includes the following raw materials in parts by weight: 100 parts of PVDF resin, 10-20 parts of maleic anhydride grafted ethylene-octene copolymer, and 10-20 parts of fluorosilicone thermoplastic polyurethane elastomer.

2. The high barrier and wrinkle-resistant aviation isolation film according to claim 1, characterized in that: The thickness of the functional protective layer is 5-10 μm; the thickness of the substrate layer is 40-60 μm; the thickness of the barrier layer is 15-25 μm; and the thickness of the anti-wrinkle layer is 10-20 μm.

3. The high barrier and wrinkle-resistant aviation isolation film according to claim 1, characterized in that: The raw material of the substrate layer is PVDF resin; the ethylene-vinyl alcohol copolymer is Soarnol™ DC3212B EVOH.

4. The high barrier and wrinkle-resistant aviation isolation film according to claim 1, characterized in that: The MXene nanosheets are titanium carbide MXene multilayer nanosheets with a thickness of 100-200 nm and a sheet diameter of 2-10 μm; the starch nanocrystals have a diameter of 10-100 nm and a length of 50-500 nm.

5. The high barrier and wrinkle-resistant aviation isolation film according to claim 3, characterized in that: The PVDF resin is Solef® 11010 PVDF.

6. The high barrier and wrinkle-resistant aviation isolation film according to claim 1, characterized in that: The maleic anhydride grafted ethylene-octene copolymer is AMPLIFY GR216.

7. The high barrier and wrinkle-resistant aviation isolation film according to claim 1, characterized in that: The functional protective layer is made of the following raw materials in parts by weight: 1-3 parts of (perfluoropropane-2,2-diyl)bis(4,1-phenylene) diacrylate, 3-5 parts of 1,3,5-triacryloylhexahydro-1,3,5-triazine, 3-5 parts of 1,4-diacryloyl-1,2,3,4-tetrahydro-6,7-dimethylquinoxaline, and 1-3 parts of 2,4,6-trivinylcycloboroxane.

8. A method for preparing a high-barrier, wrinkle-resistant aviation isolation film according to any one of claims 1 to 7, characterized in that: The steps include: Step S1, preparing a barrier layer masterbatch: adding the raw materials of the barrier layer according to parts by weight into a twin-screw extruder, extruding at a temperature of 180-200° C. and a screw speed of 200-250 r / min, and blending, extruding and granulating to obtain a barrier layer masterbatch; Step S2, preparation of anti-wrinkle layer masterbatch: adding the raw materials of the anti-wrinkle layer according to weight into a twin-screw extruder, extruding at a temperature of 170-190° C. and a screw speed of 180-220 r / min, blending, extruding and granulating to obtain the anti-wrinkle layer masterbatch; Step S3, film casting: using a multi-layer co-extrusion casting process, the base material PVDF, the barrier layer masterbatch and the anti-wrinkle layer masterbatch are added to different extruders respectively, and co-extruded through the die head to form a film; Step S4, biaxial stretching: biaxially stretching the film obtained by casting, heat-setting it, and then cooling it to room temperature to obtain a primary film; Step S5, radiation grafting: After uniformly mixing the raw materials of the functional protective layer by weight, a mixed raw material is obtained, the mixed raw material is dispersed in tetrahydrofuran to obtain a dispersion, and the dispersion is uniformly coated on the surface of the primary film. The film is irradiated under an electron beam in a nitrogen atmosphere and then placed at 95-105° C. for 3-5 hours to obtain a high-barrier and wrinkle-resistant aviation isolation film.

9. The method for preparing a high-barrier, wrinkle-resistant aviation isolation film according to claim 8, wherein: The extrusion temperatures of each layer of the co-extrusion cast film in step S3 are: 180-200°C for the substrate layer, 200-210°C for the barrier layer, and 180-190°C for the anti-wrinkle layer; the temperature for the biaxial stretching in step S4 is 110-120°C, and the stretching ratio is 3-5 times; the heat setting temperature in step S4 is 165-175°C, and the holding time is 10-30s.

10. The method for preparing a high-barrier, wrinkle-resistant aviation isolation film according to claim 8, characterized in that: The mass ratio of the mixed raw material and tetrahydrofuran in step S5 is (8-12):100; the irradiation in step S5 is carried out at room temperature, is continuous electron beam irradiation, has an absorbed dose of 100 to 400 kGy, a beam current of 25 to 110 mA, a voltage of 300 to 500 kV, and a radiation dose rate of 8 to 12 kGy / h.