Flexible composite material and method for producing the same

Abstract

The application discloses a flexible composite material and a preparation method thereof. The flexible composite material comprises a weather-resistant film, a first gas barrier layer, a first adhesive layer, a second gas barrier layer, a plastic film, a second adhesive layer, a functionalized fiber fabric layer and a heat-sealing layer which are sequentially arranged. The functionalized fiber fabric layer comprises a fiber fabric and a modified substance. The modified substance is attached to the surface of fiber filaments of the fiber fabric. The modified substance comprises an inorganic-organic hybrid polymer. Thus, the strength, weather resistance and gas barrier property of the flexible composite material can be improved.

Description

Technical Field

[0001] This invention belongs to the field of airships, specifically relating to flexible composite materials and their preparation methods. Background Technology

[0002] An aerostat is an aircraft that uses a gas lighter than air to provide lift. Due to its advantages such as long loiter time, energy efficiency, environmental friendliness, and economy, it is widely used in military and civilian fields. The capsule material is a core structural component of the aerostat, requiring high strength, good weather resistance, good tear resistance, low gas permeability, and good processability. As the main load-bearing structure, a single material cannot meet its performance requirements, while composite materials suffer from poor overall performance and short service life.

[0003] Therefore, current flexible composite materials and their preparation methods still need improvement. Summary of the Invention

[0004] This application is based on the inventor's discovery of the following problems:

[0005] Composite materials in related technologies typically include structures such as weather-resistant layers, barrier layers, and load-bearing layers. The inventors discovered that during processing or in the service of the airship, the capsule material is subjected to environmental tests such as kneading, friction, bending, flexing, dragging, and prolonged continuous stress. The composite materials used as capsule materials in related technologies suffer a decrease in strength, weather resistance, and air-barrier properties due to repeated kneading and bending, thereby affecting the service life of the airship.

[0006] This application aims to at least partially alleviate or resolve at least one of the aforementioned problems.

[0007] In one aspect of this application, a flexible composite material is proposed, comprising a weather-resistant film, a first gas barrier layer, a first adhesive layer, a second gas barrier layer, a plastic film, a second adhesive layer, a functionalized fiber fabric layer, and a heat-sealing layer, sequentially stacked. The functionalized fiber fabric layer comprises fiber fabric and a modifying substance, the modifying substance being attached to the surface of the fiber fabric, and the modifying substance comprising an inorganic-organic hybrid polymer. This improves the strength, weather resistance, and gas barrier properties of the flexible composite material.

[0008] According to embodiments of the present invention, the fiber fabric includes at least one of polyimide fiber fabric, poly(p-phenylenebisoxazole) fiber fabric, ultra-high molecular weight polyethylene fiber fabric, aromatic polyamide fiber fabric, aromatic polyester fiber fabric, aliphatic polyamide fiber fabric, and aliphatic polyester fiber fabric. This further improves the strength of the flexible composite material.

[0009] According to an embodiment of the present invention, the first gas barrier layer comprises at least one of an inorganic hybrid modified hydroxyl polymer and an inorganic hybrid modified carboxyl polymer, and the second gas barrier layer comprises a barrier layer material, wherein the barrier layer material comprises at least one of alumina, silicon oxide, silicon nitride, titanium oxide, and zirconium oxide. This further improves the gas barrier performance of the flexible composite material.

[0010] According to an embodiment of the present invention, the thickness of the fiber fabric is 30μm-250μm, and the areal density is 25g / m³. 2 -250g / m 2 This further improves the strength and tear resistance of flexible composite materials.

[0011] According to an embodiment of the present invention, the thickness of the first gas barrier layer is 0.1 μm-2 μm. This further improves the gas barrier performance of the flexible composite material.

[0012] According to an embodiment of the present invention, the thickness of the second gas barrier layer is 10 nm to 100 nm. This further improves the gas barrier performance of the flexible composite material.

[0013] According to an embodiment of the present invention, the flexible composite material satisfies at least one of the following conditions: the thickness of the weather-resistant film is 8 μm-35 μm; the thickness of the plastic film is 6 μm-25 μm; the thickness of the heat-sealing layer is 20 μm-50 μm; and the adhesive application amount of the first adhesive layer is 3 g / m². 2 -15g / m 2 The amount of adhesive applied to the second adhesive layer is 10 g / m². 2 -30g / m 2 This further improves the tumbling resistance and weather resistance of flexible composite materials.

[0014] In another aspect of the present invention, a method for preparing the aforementioned flexible composite material is provided, comprising: modifying a fiber fabric to obtain a functionalized fiber fabric layer; corona treating one side surface of a weather-resistant film, and forming a first gas barrier layer on the corona-treated side surface of the weather-resistant film using a first coating process to obtain a gas barrier weather-resistant film; forming a second gas barrier layer on one side surface of a plastic film using a deposition process to obtain a gas barrier plastic film; positioning the gas barrier weather-resistant film and the gas barrier plastic film opposite to each other, and bonding the first gas barrier layer and the second gas barrier layer using a first adhesive to obtain a first composite film; positioning the first composite film and the functionalized fiber fabric layer opposite to each other, and bonding the plastic film and the functionalized fiber fabric layer using a second adhesive to obtain a second composite film; and forming the heat-sealing layer on the side surface of the functionalized fiber fabric layer away from the plastic film using a second coating process to obtain the flexible composite material. Therefore, by modifying the fiber fabric to obtain a functionalized fiber fabric layer, and by setting a double-layer gas barrier layer, a flexible composite material with good rubbing resistance, strength, gas barrier properties and weather resistance can be obtained.

[0015] According to an embodiment of the present invention, the modification treatment includes dip-coating the fiber fabric in a coating solution and drying the dip-coated fiber fabric. Thus, a fiber fabric containing a surface-modifying substance can be obtained.

[0016] According to an embodiment of the present invention, the dip-coating treatment time is 5s-120s, the drying treatment temperature is 80℃-135℃, and the drying treatment time is 2min-3min. This further promotes the formation of an inorganic-organic hybrid polymer coating on the surface of the fiber fabric.

[0017] According to an embodiment of the present invention, the dip coating solution comprises 1.5-25 parts by weight of a grafting agent, 0.2-2.5 parts by weight of a film-forming agent, 0.01-0.5 parts by weight of an initiator, and 20-2000 parts by weight of a solvent. Thus, the grafting agent acts as a bridge, promoting the combined action of the initiator and the film-forming agent in the dip coating solution, thereby forming a uniform inorganic-organic hybrid polymer coating on the surface of the fibrous fabric.

[0018] According to embodiments of the present invention, the grafting agent comprises at least one of methyl methacrylate, butyl acrylate, acrylic acid, hydroxypropyl acrylate, hydroxyethyl acrylate, N-hydroxymethylacrylamide, propyl methacrylate triethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, γ-ureidopropyltrimethoxysilane, γ-ureidotriethoxysilane, γ-isocyanate-propyltrimethoxysilane, γ-isocyanate-triethoxysilane, and trimethyl propylene phosphate, tetraisopropoxytitanium, triisopropoxyaluminum, aluminum trichloride, titanium tetrachloride, and zirconium tetrachloride. Thus, the grafting agent acts as a bridge, achieving adsorption on the surface of the fiber fabric through its own active groups, thereby forming a uniform inorganic-organic hybrid polymer coating on the surface of the fiber fabric.

[0019] According to embodiments of the present invention, the film-forming agent comprises a water-soluble polymer, wherein the water-soluble polymer comprises at least one of polyacrylamide, polyvinylpyrrolidone, polyacrylic acid, polymethacrylic acid, poly(acrylic acid / methacrylic acid) copolymer, polyvinyl alcohol, polyethyleneimine, polyethylene oxide, ethylene-vinyl alcohol copolymer, polyethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, polysaccharides, chitosan, and cellulose. Thus, the film-forming agent can promote the formation of a uniform inorganic-organic hybrid polymer coating on the surface of fibrous fabrics.

[0020] According to embodiments of the present invention, the initiator comprises at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, azobisisovalerate, dopamine hydrochloride, azobisisobutyramidine hydrochloride, azobisisobutyramidazoline hydrochloride, azobisisobutyramidazoline, and azobiscyanopentanoic acid. This initiates the self-polymerization reaction of unsaturated double or triple bonds in the grafting agent, promoting the formation of an inorganic-organic hybrid polymer coating on the surface of the fibrous fabric by the grafting agent and the film-forming agent.

[0021] According to embodiments of the present invention, the solvent comprises a mixed solution of water and an alcohol, wherein the alcohol comprises at least one of methanol, ethanol, isopropanol, and n-propanol. This facilitates the formation of a uniform inorganic-organic hybrid polymer coating on the surface of the fibrous fabric. Attached Figure Description

[0022] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0023] Figure 1 This is a schematic diagram of the structure of a flexible composite material according to an embodiment of this application;

[0024] Figure 2 This is a process flow diagram for preparing flexible composite materials according to an embodiment of this application.

[0025] Explanation of reference numerals in the attached figures:

[0026] 10: Weather-resistant film; 20: First gas barrier layer; 30: First adhesive layer; 40: Second gas barrier layer; 50: Plastic film; 60: Second adhesive layer; 70: Functionalized fiber fabric layer; 80: Heat-sealing layer. Detailed Implementation

[0027] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0028] In one aspect of the invention, a flexible composite material is provided, with reference to... Figure 2 The system comprises, in sequence, a weather-resistant film 10, a first gas barrier layer 20, a first adhesive layer 30, a second gas barrier layer 40, a plastic film 50, a second adhesive layer 60, a functionalized fiber fabric layer 70, and a heat-sealing layer 80. Specifically, the functionalized fiber fabric layer 70 includes fiber fabric and a modifying substance. The modifying substance, including an inorganic-organic hybrid polymer, is attached to the surface of the fiber fabric, improving the rub resistance and bending resistance of the fiber fabric, thereby enhancing the rub resistance of the flexible composite material. The weather-resistant film 10 improves the weather resistance of the flexible composite material. The first gas barrier layer 20 and the second gas barrier layer 40 effectively improve the gas barrier performance of the flexible composite material during rubbing and bending, thereby improving the strength and gas barrier properties of the flexible composite material during rubbing and bending. The first adhesive layer 30 and the second adhesive layer 60 improve the structural stability of the flexible composite material, and the plastic film 50 effectively supports the second gas barrier layer 60.

[0029] To facilitate understanding, the principle behind the aforementioned beneficial effects of the flexible composite material in this application is explained below:

[0030] The inventors discovered that in the actual use of flexible composite materials, some fibers in the fiber fabric layer break during rubbing or bending, directly leading to a significant reduction in the strength of the flexible composite material. In this application, the inventors found that when the surface of the fiber filaments in the fiber fabric has a uniform inorganic-organic hybrid polymer coating, the inorganic-organic hybrid polymer coating can effectively improve the damage to the fiber filaments during rubbing and bending, thereby enhancing the flexibility and abrasion resistance of the fiber fabric. On the other hand, the inorganic-organic hybrid polymer coating can improve the inertia of the high-modulus fiber fabric surface, enhance the adhesion between the functionalized fiber fabric layer and the heat-sealing layer, and thus improve the overall rubbing resistance of the flexible composite material.

[0031] According to some embodiments of the present invention, the functionalized fiber fabric layer is formed by modifying the surface of the fiber fabric. The modification process involves immersing the fiber fabric in an immersion coating solution, wherein the immersion coating solution includes a grafting agent, a film-forming agent, an initiator, and a solvent. Specifically, the immersion coating solution can form a uniform inorganic-organic hybrid polymer coating on the surface of the fiber filaments in the fiber fabric. The inorganic-organic hybrid polymer coating includes an inorganic-organic hybrid polymer, which includes at least one of an inorganic-organic hybrid hydroxyl polymer, an inorganic-organic hybrid polyurethane polymer, an inorganic-organic hybrid carboxyl polymer, and an inorganic-organic metal-oxygen-carbon bond polymer. Thus, by attaching the inorganic-organic hybrid polymer to the surface of the fiber fabric, the rub resistance of the flexible composite material is improved.

[0032] According to some embodiments of the present invention, the functionalized fiber fabric layer serves as a load-bearing layer in a flexible composite material. The type of fiber fabric in the functionalized fiber fabric layer is not particularly limited. For example, the fiber fabric may include at least one of polyimide fiber fabric, poly(p-phenylenebisoxazole) fiber fabric, ultra-high molecular weight polyethylene fiber, aromatic polyamide fiber, aromatic polyester fiber, aliphatic polyamide fiber, and aliphatic polyester fiber. Thus, the aforementioned fiber fabric can enable the functionalized fiber fabric layer to have better strength and load-bearing capacity.

[0033] According to some embodiments of the present invention, the fiber fabric is woven from fiber filaments. The fineness of the fiber filaments in the fiber fabric is not particularly limited. For example, the fineness of the fiber filaments can be 5 denier to 1200 denier. When the fineness of the fiber filaments is 5 denier to 1200 denier, the fiber fabric woven from fiber filaments of this fineness can improve the overall strength and load-bearing effect of the functional fiber fabric layer, thereby enabling the areal density of the fiber fabric to meet the design requirements of flexible composite materials.

[0034] According to some embodiments of the present invention, the first gas barrier layer and the second gas barrier layer are provided to enable the flexible composite material to have better gas barrier properties. The first gas barrier layer may be made of at least one of inorganic hybrid modified hydroxyl polymers and inorganic hybrid modified carboxyl polymers. The second gas barrier layer comprises a barrier layer material, which may include at least one of alumina, silicon oxide, silicon nitride, titanium oxide, and zirconium oxide. The particle size of the barrier layer material may be at the nanometer level. Specifically, the first gas barrier layer formed by inorganic hybrid modified hydroxyl polymers and / or inorganic hybrid modified carboxyl polymers has high specific strength and low permeability. The second gas barrier layer formed by the barrier layer material with a nanometer-sized particle size has good shear stress and is less prone to breakage and leakage during repeated kneading. Therefore, the first gas barrier layer can improve the gas barrier performance of the second gas barrier layer. The second gas barrier layer and the first gas barrier layer work synergistically to effectively improve the gas barrier performance of the flexible composite material.

[0035] According to some embodiments of the present invention, the types of gases that the first gas barrier layer and the second gas barrier layer can block are not particularly limited. For example, the gas may include at least one of hydrogen, helium and hot gas.

[0036] According to some embodiments of the present invention, the weather-resistant film, as a weather-resistant unit in a flexible composite material, is not particularly limited in type. For example, the weather-resistant film may include at least one of polyvinylidene fluoride film, polyvinylidene fluoride film, ethylene-tetrafluoroethylene copolymer film, polyimide film, polyurethane film, and liquid crystal polyester film.

[0037] According to some embodiments of the present invention, the plastic film serves as the support for the second helium barrier layer, and its type is not particularly limited. For example, the type of plastic film may include at least one of polyethylene phthalate film, polyethylene naphthalate film, polypropylene film, polyamide film, polyethylene film, and polypropylene film. When the type of plastic film is the aforementioned material, the weather resistance of the flexible composite material can be effectively improved.

[0038] According to some embodiments of the present invention, the heat-sealing layer is a protective layer disposed on the outermost layer of the flexible composite material. The material of the heat-sealing layer is not particularly limited. For example, the heat-sealing layer may include at least one of polyester-type polyurethane elastomer, polyether-type polyurethane elastomer, polycaprolactone-type polyurethane elastomer, polyolefin elastomer, polystyrene-based elastomer, polyether ester elastomer, and polyamide elastomer. When the heat-sealing layer is made of the aforementioned materials, on the one hand, hydrogen bonds exist inside the aforementioned thermoplastic elastomer. Under the action of hydrogen bonds, the heat-sealing layer and the functionalized fiber fabric layer have good interfacial compatibility. On the other hand, the thermoplastic elastomer has a certain adhesion, which enables the surface of the capsule material to have anti-fouling and abrasion resistance, as well as improve the rubbing resistance of the capsule material.

[0039] According to some embodiments of the present invention, the adhesive layer can firmly bond the layers of the flexible composite material together, so that the flexible composite material will not slip off between layers after repeated flexing, and has good weather resistance, tensile strength and shear strength. The materials of the first adhesive layer and the second adhesive layer are not particularly limited. For example, the materials of the first adhesive layer and the second adhesive layer can each independently include at least one of polyurethane adhesive, polyester adhesive and polyacrylate adhesive. When the materials of the first adhesive layer and the second adhesive layer are the aforementioned materials, the first adhesive layer can effectively bond the first gas barrier layer and the second gas barrier layer, and the second adhesive layer can effectively bond the plastic film and the functionalized fiber fabric layer.

[0040] According to some embodiments of the present invention, the fiber fabric layer is not particularly limited. For example, the thickness of the fiber fabric can be 30μm-250μm. When the thickness of the fiber fabric is less than 30μm, the fiber fabric is too thin, which will cause the functional fiber fabric layer to break more easily during rubbing or bending, thereby reducing the strength of the flexible composite material. When the thickness of the fiber fabric is greater than 250μm, the fiber fabric is too thick. When the total thickness of the flexible composite material is fixed, the thickness of other layers needs to be reduced accordingly, which ultimately leads to a reduction in the weather resistance, strength, gas barrier properties and rubbing resistance of the flexible composite material. When the thickness of the fiber fabric is 30μm-250μm, the flexible composite material has better rubbing resistance and strength.

[0041] According to some embodiments of the present invention, the areal density of the fiber fabric is not particularly limited; for example, the areal density of the fiber fabric can be 25 g / m². 2 -250g / m 2 When the areal density of the fiber fabric is less than 25 g / m² 2 When the areal density of the fiber fabric is too low, the amount of inorganic-organic hybrid polymers that can adhere to the surface of the fibers in the fiber fabric is relatively small, which leads to a decrease in the rub resistance and strength of the flexible composite material. When the areal density of the fiber fabric is greater than 250 g / m³, the rub resistance and strength of the flexible composite material will decrease.2 When the areal density of the fiber fabric is 25 g / m³, it will lead to a decrease in the flexibility of the flexible composite material. 2 -250g / m 2 At that time, flexible composite materials have good resistance to tumbling and strength.

[0042] According to some embodiments of the present invention, the thickness of the first gas barrier layer is not particularly limited. For example, the thickness of the first gas barrier layer can be 0.1 μm-2 μm. When the thickness of the first gas barrier layer is less than 0.1 μm, the thickness of the first gas barrier layer is too low, which will reduce the gas barrier performance of the first gas barrier layer. When the thickness of the first gas barrier layer is greater than 2 μm, the thickness of the first gas barrier layer is too thick, which will lead to an increase in the areal density of the flexible composite material. The increase in the areal density of the flexible composite material will lead to a reduction in the effective load of the airship, which is not conducive to the practical application of the airship. When the thickness of the first gas barrier layer is 0.1 μm-2 μm, the flexible composite material has better gas barrier performance.

[0043] According to some embodiments of the present invention, the thickness of the second gas barrier layer is not particularly limited. For example, the thickness of the second gas barrier layer can be 10nm-100nm. When the thickness of the second gas barrier layer is less than 10nm, the thickness of the second gas barrier layer is too low, which will reduce the gas barrier performance of the second gas barrier layer. When the thickness of the second gas barrier layer is greater than 100nm, the thickness of the second gas barrier layer is too thick, which will lead to an increase in the areal density of the flexible composite material and an increase in material cost. When the thickness of the second gas barrier layer is 10nm-100nm, the double-layer design of the first gas barrier layer and the second gas barrier layer enables the flexible composite material to have better gas barrier performance.

[0044] According to some embodiments of the present invention, the thickness of the weather-resistant film is not particularly limited. For example, the thickness of the weather-resistant film can be 8μm-35μm. When the thickness of the weather-resistant film is less than 8μm, the thickness is too low and will reduce the weather resistance of the flexible composite material. When the thickness of the weather-resistant film is greater than 35μm, the thickness is too high and will lead to an increase in the areal density of the flexible composite material and an increase in material cost. When the thickness of the weather-resistant film is within the aforementioned range, the resulting flexible composite material has better weather resistance.

[0045] According to some embodiments of the present invention, the thickness of the plastic film is not particularly limited. For example, the thickness of the plastic film can be 6μm-25μm. When the thickness of the plastic film is less than 6μm, the plastic film is too thin. When the second gas barrier layer is formed by the deposition process, it will cause the second gas barrier layer to be unevenly formed, thereby reducing the gas barrier effect of the second gas barrier layer. When the thickness of the plastic film is greater than 25μm, the plastic film is too thick, which will lead to an increase in the areal density of the flexible composite material and an increase in material cost. When the thickness of the plastic film is within the aforementioned range, the gas barrier performance of the flexible composite material obtained therefrom is better.

[0046] According to some embodiments of the present invention, the thickness of the heat-sealing layer is not particularly limited. For example, the thickness of the heat-sealing layer can be 20μm-50μm. When the thickness of the heat-sealing layer is less than 20μm, the heat-sealing layer is too thin, and the adhesion between the heat-sealing layer and the functional fiber fabric layer is reduced. When the thickness of the heat-sealing layer is greater than 50μm, it will lead to an increase in the areal density of the flexible composite material and an increase in material cost. When the thickness of the heat-sealing layer is within the aforementioned range, the heat-sealing layer and the functional fiber fabric layer can be effectively bonded, thereby effectively protecting the functional fiber fabric layer and further improving the rub resistance and strength of the flexible composite material.

[0047] According to some embodiments of the present invention, the first adhesive layer and the second adhesive layer serve as a medium connecting the layers to ensure that the layers of the flexible composite material do not slip relative to each other during kneading and flexing. The first adhesive layer bonds the first gas barrier layer and the second gas barrier layer, and the second adhesive layer bonds the plastic film and the functionalized fiber fabric layer. Therefore, the amount of adhesive applied to the first and second adhesive layers must be moderate. If the amount of adhesive is too low, the adhesion between the layers of the flexible composite material will be poor, and there is a risk of slippage between the layers during actual use. If the amount of adhesive is too high, the areal density and material cost of the flexible composite material will increase. Therefore, the amount of adhesive applied to the first adhesive layer is 3 g / m³. 2 -15g / m 2 The amount of adhesive applied to the second adhesive layer is 10g / m². 2 -30g / m 2 .

[0048] According to some embodiments of the present invention, the areal density of the flexible composite material can be 40 g / m³. 2 -450g / m 2 The thickness can range from 90μm to 500μm, and the areal density of the flexible composite material is greater than 450g / m³. 2 If the areal density of the flexible composite material is too high, the weight of the airship using this material will increase, thus reducing the effective payload of the airship. When the areal density of the flexible composite material is less than 40 g / m³... 2When the surface density of each layer of the flexible composite material is 40 g / m³, it indicates that the surface density of the materials is relatively low, resulting in low resistance to tearing and low strength of the flexible composite material, which cannot meet the material performance requirements of the airship. 2 -450g / m 2 At that time, the flexible composite material had good resistance to rubbing and strength, which could meet the material performance requirements of the airship.

[0049] In another aspect of the invention, a method for preparing the aforementioned flexible composite material is provided, referring to... Figure 2 This includes the following steps:

[0050] S100: Modification treatment of fiber fabrics

[0051] According to some embodiments of the present invention, the fiber fabric is modified in this step to obtain a functionalized fiber fabric layer. The modification process involves immersing the fiber fabric in an immersion coating solution and then drying the immersion-coated fiber fabric. The immersion coating time is not particularly limited. For example, the immersion coating time can be 5s-120s. When the immersion coating time is 5s-120s, it can promote the formation of a uniform inorganic-organic hybrid polymer coating on the surface of the fiber filaments of the fiber fabric.

[0052] According to some embodiments of the present invention, the fiber fabric that has undergone dip coating is dried so that the solvent in the dip coating solution on the surface of the fiber fabric evaporates. The drying temperature can be 80°C-135°C and the drying time can be 2 min-3 min.

[0053] According to some embodiments of the present invention, the composition of the dip coating solution is not particularly limited. For example, the dip coating solution may include 1.5-25 parts by weight of grafting agent, 0.2-2.5 parts by weight of film-forming agent, 0.01-0.5 parts by weight of initiator and 20-2000 parts by weight of solvent. Therefore, the impregnation solution can form a uniform inorganic-organic hybrid polymer coating on the surface of the fiber. Specifically, when the amount of grafting agent in the impregnation solution is greater than 25 parts by weight, the excessive content of grafting agent will cause the flexibility of the fiber fabric after impregnation to deteriorate. When the amount of grafting agent in the impregnation solution is less than 1.5 parts by weight, the amount of grafting agent added is too low, which will lead to a poor modification effect of the fiber fabric and make it difficult to improve the rub resistance and strength of the flexible composite material. When the amount of initiator in the impregnation solution is greater than 0.5 parts by weight, the excessive amount of initiator added will cause the stability of the impregnation solution to deteriorate. When the amount of initiator in the impregnation solution is less than 0.01 parts by weight, the insufficient amount of initiator added will cause the coating formed on the surface of the fiber fabric to be uneven, thereby affecting the modification effect of the fiber fabric.

[0054] According to some embodiments of the present invention, the grafting agent can enhance the adsorption on the fiber surface through its own activity, and can also work together with the initiator and film-forming agent on the fiber surface to form a uniform protective layer. In this invention, the grafting agent is an organic compound containing unsaturated double or triple bonds and / or a metal complex containing aluminum, titanium, zirconium, etc., having three or more coordination centers. Specifically, the grafting agent may include at least one of methyl methacrylate, butyl acrylate, acrylic acid, hydroxypropyl acrylate, hydroxyethyl acrylate, N-hydroxymethylacrylamide, propyl methacrylate triethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, γ-ureidopropyltrimethoxysilane, γ-ureidotriethoxysilane, γ-isocyanate-propyltrimethoxysilane, γ-isocyanate-triethoxysilane, and trimethyl propenyl phosphate, tetraisopropoxytitanium, triisopropoxyaluminum, aluminum trichloride, titanium tetrachloride, and zirconium tetrachloride.

[0055] According to some embodiments of the present invention, the film-forming agent may include a water-soluble polymer, which includes at least one of polyacrylamide, polyvinylpyrrolidone, polyacrylic acid, polymethacrylic acid, poly(acrylic acid / methacrylic acid) copolymer, polyvinyl alcohol, polyethyleneimine, polyethylene oxide, ethylene-vinyl alcohol copolymer, polyethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, polysaccharides, chitosan, and cellulose, wherein the mass ratio of grafting agent to film-forming agent in the dipping solution may be 3 / 5 to 250 / 2.

[0056] According to some embodiments of the present invention, the initiator can initiate the self-polymerization of unsaturated double or triple bonds in the grafting agent, promoting the formation of an inorganic-organic hybrid polymer coating on the surface of the fiber filaments of the grafting agent and the film-forming agent. The initiator includes at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate and azobisisovalerate, dopamine hydrochloride, azobisisobutyramidine hydrochloride, azobisisobutyramidoline hydrochloride, azobisisobutyramidoline and azobiscyanopentanoic acid. The mass ratio of the initiator to the grafting agent in the dipping solution can be 1 / 2500-1 / 3.

[0057] According to some embodiments of the present invention, the solvent comprises a mixed solution of water and alcohol. Specifically, the alcohol comprises at least one of methanol, ethanol, isopropanol and n-propanol. The weight ratio of alcohol to water is 2 / 1 to 50 / 1, preferably 3 / 1 to 10 / 1. If the amount of alcohol added is too small, it will be detrimental to the dispersion of film-forming agent, grafting agent and initiator in the solvent, thereby resulting in poor wettability of the dip coating solution on the surface of the fiber fabric. If the amount of alcohol added is too large, the solid content of the dip coating solution will be low, thereby affecting the modification effect of the fiber fabric.

[0058] According to some embodiments of the present invention, the solid content of the impregnation solution is not particularly limited. For example, the solid content of the impregnation solution can be 0.1%-10%. When the solid content of the impregnation solution is less than 0.1%, the solid content of the impregnation solution is too low, and the content of inorganic-organic hybrid polymers in the impregnation solution is too low. This results in less or uneven content of inorganic-organic hybrid polymers adhering to the surface of the fiber fabric during the impregnation process, thereby reducing the effect of fiber fabric modification treatment. When the solid content of the impregnation solution is greater than 10%, the solid content of the impregnation solution is too high, and the content of inorganic-organic hybrid polymers in the impregnation solution is high. This results in an excessively high content of inorganic-organic hybrid polymers adhering to the surface of the fiber fabric during the impregnation process, which in turn leads to poor flexibility of the functional fiber fabric layer and reduces the rub resistance of the flexible composite material.

[0059] According to some embodiments of the present invention, a fiber fabric is modified to obtain a functionalized fiber fabric layer. The modification process involves immersing the fiber fabric in an immersion coating solution, which forms a uniform inorganic-organic hybrid polymer coating on the surface of the fiber filaments in the fiber fabric. The inorganic-organic hybrid polymer includes at least one of inorganic-organic hybrid hydroxyl polymers, inorganic-organic hybrid polyurethane polymers, inorganic-organic hybrid carboxyl polymers, and inorganic-organic metal-oxygen-carbon bond polymers. Thus, by attaching the inorganic-organic hybrid polymer to the surface of the fiber fabric, the rub resistance of the flexible composite material is improved.

[0060] S200: One side surface of the corona-treated weather-resistant film, and a first gas barrier layer is formed on the corona-treated side surface through a first coating process.

[0061] According to some embodiments of the present invention, in this step, a gas barrier weather-resistant film is obtained by corona treatment on one side surface of the weather-resistant film and forming a first gas barrier layer on the corona-treated side surface through a first coating process. The first coating process may include at least one of the following: roller coating, gravure coating, doctor blade coating, slot coating, extrusion coating, air knife coating, dip coating, spraying, casting process and lamination.

[0062] S300: A second gas barrier layer is formed on one side surface of the plastic film through a deposition process.

[0063] According to some embodiments of the present invention, in this step, a second gas barrier layer is formed on one side surface of the plastic film by a deposition process to obtain a gas barrier plastic film, wherein the deposition process may include at least one of vacuum thermal evaporation, electron beam evaporation, magnetron sputtering, and plasma chemical vapor deposition.

[0064] S400: The first gas barrier layer and the second gas barrier layer are bonded together using a first adhesive.

[0065] According to some embodiments of the present invention, in this step, the first gas barrier layer of the gas barrier weather-resistant film and the second gas barrier layer of the gas barrier plastic film are arranged opposite to each other, and the first gas barrier layer and the second gas barrier layer are bonded together using a first adhesive to obtain a first composite film.

[0066] S500: A second adhesive is used to bond the plastic film to the functionalized fiber fabric layer.

[0067] According to some embodiments of the present invention, in this step, the plastic film of the first composite film is arranged opposite to the functional fiber fabric layer, and the plastic film and the functional fiber fabric layer are bonded together using a second adhesive to obtain the second composite film.

[0068] S600: A heat-sealing layer is formed on the surface of the functionalized fiber fabric layer away from the plastic film using a second coating process.

[0069] According to some embodiments of the present invention, in this step, a heat-sealing layer is formed on the surface of the functionalized fiber fabric layer away from the plastic film by a second coating process to obtain a flexible composite material, wherein the second coating process may include at least one of vacuum thermal evaporation, electron beam evaporation, magnetron sputtering, and plasma chemical vapor deposition.

[0070] According to some embodiments of the present invention, the flexible composite material prepared by the aforementioned method has good tumbling resistance, high strength, low areal density and good weather resistance, and can be widely used as the capsule material of airships such as stratospheric airships, tropospheric airships, tethered balloons and high-altitude balloons.

[0071] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0072] Example 1

[0073] Preparation of modified coating solution: 11.3 parts by weight of γ-ureopropyltrimethoxysilane was selected as the grafting agent, 0.5 parts by weight of 5% polyvinyl alcohol solution was selected as the film-forming agent, 0.01 parts by weight of azobisisobutyronitrile was selected as the initiator, and water and isopropanol solution were selected as the solvent, wherein the solvent was 2000 parts by weight, and the solution was mixed evenly at room temperature.

[0074] Preparation of flexible composite materials: The weather-resistant film is a 25μm thick polyvinyl fluoride film; the first gas barrier layer is a 0.15μm thick polyvinyl alcohol / polyacrylic acid barrier coating liquid; the second gas barrier layer is a 12nm thick silicon dioxide barrier layer; the plastic film is a 10μm thick polyethylene terephthalate film; and the functionalized fiber fabric layer uses a fiber fabric with an areal density of 110g / m². 2 The fabric is made of 80μm thick polyimide fiber, the heat-sealing layer is made of thermoplastic polyurethane, and the first adhesive layer and the second adhesive layer are made of two-component polyurethane adhesive.

[0075] The specific preparation process of the flexible composite material is as follows: The fiber fabric is dipped in a coating solution on a dip coating device. After dip coating, it is cured at 85℃ for 5 minutes and then wound up to complete the preparation of the functional fiber fabric layer. The weather-resistant film coating surface is corona-treated, and then a first gas barrier layer of polyvinyl alcohol / polyacrylic acid is coated on a micro-gravure coating device. After coating, it is cured at 85℃ for 3 minutes and then wound up to complete the preparation of the helium-barrier weather-resistant film. A second gas barrier layer is formed on one side surface of the plastic film through a deposition process to obtain a gas-barrier plastic film. The gas-barrier weather-resistant film and the gas-barrier plastic film are placed opposite each other, and the first gas barrier layer and the second gas barrier layer are bonded together using a first adhesive to obtain a first composite film. The first composite film and the functional fiber fabric layer are placed opposite each other, and the plastic film and the functional fiber fabric layer are bonded together using a second adhesive to obtain a second composite film. A heat-sealing layer is formed on the side surface of the functional fiber fabric layer away from the plastic film through a second coating process to obtain the flexible composite material.

[0076] Examples 2-18 are the same as Example 1, except that the thickness of the functional fiber fabric layer, the areal density of the functional fiber fabric layer, the material of the functional fiber fabric layer, the amount of grafting agent, the amount of film-forming agent, the amount of initiator, the amount of solvent, the thickness of the first gas barrier layer, and the thickness of the second gas barrier layer are as shown in Table 1.

[0077] Comparative Examples 1-9 are the same as Example 1, except that the flexible composite material in Comparative Example 1 does not have a first gas barrier layer, the flexible composite material in Comparative Example 2 does not have a second gas barrier layer, and the functional fiber fabric layer in Comparative Example 3 does not undergo surface modification treatment. For the thickness, areal density, material, amount of grafting agent, amount of film-forming agent, amount of initiator, amount of solvent, thickness of the first gas barrier layer, and thickness of the second gas barrier layer in Comparative Examples 4-9, please refer to Table 1 for details.

[0078] Table 1

[0079]

[0080]

[0081]

[0082] The flexible composite materials in Examples 1-18 and Comparative Examples 1-9 were subjected to the following tests, and the results are shown in Table 2:

[0083] (1) Surface density test: The test was conducted in accordance with the national standard GB / T4669-2008 "Determination of unit length mass and unit area mass of textile woven fabrics".

[0084] (2) Tensile strength test: The test was conducted in accordance with the American standard FED-STD-191A5102.

[0085] (3) Helium permeability test: The test was conducted in accordance with the national standard GB / T1038-2000 "Gas permeability test method for plastic films and sheets - differential pressure method".

[0086] (4) Test of rubbing resistance: The rubbing resistance of the flexible composite material was tested according to the American standard ASTM F392-93. Specifically, the flexible composite material was cut into a sample with a length of 30cm and a width of 21cm, and rubbed continuously for 1000 times on a blue light rubbing tester. The tensile strength and helium permeability of the flexible composite material before and after rubbing were tested.

[0087] (5) Flexural strength test: The flexural strength test of flexible composite materials was conducted according to QB / T2714-2018 "Determination of flexural strength of leather physical and mechanical tests". Specifically, the flexible composite material was cut into samples with a length of 30cm and a width of 21cm. The samples were flexed continuously for 1000 times on a flexural strength tester. The helium permeability of the flexible composite material before and after flexing was tested, and the damage of the samples after 1000 flexings was observed under a magnifying glass. The appearance evaluation of the flexible composite material after 1000 flexings included: excellent: no obvious creases and good condition; good: obvious creases and basically good condition; acceptable: obvious creases but no damage was found; poor: damage and delamination between the film and the fabric.

[0088] Table 2

[0089]

[0090]

[0091] As shown in the table above, the flexible composite materials prepared in Examples 1-18 all exhibit excellent resistance to rubbing. The decrease rate of transverse and longitudinal tensile strength after 1000 rubbing cycles is less than 10%, and the helium permeability of the prepared flexible composite materials after 1000 rubbing cycles is ≤0.5 L / m. 2 In Comparative Example 1, the surface of the flexible composite weather-resistant film was not coated with a first gas barrier layer, resulting in poor helium barrier performance. In Comparative Example 2, the flexible composite material did not contain a second gas barrier layer, leading to poor helium barrier performance. In Comparative Example 3, the functional fiber fabric layer of the flexible composite material was not modified, resulting in severe fabric damage during rubbing and a significant decrease in the tensile strength of the material. Furthermore, due to fiber fabric breakage, leaks occurred in the first gas barrier layer, the second gas barrier layer, and the weather-resistant film, causing air leakage in the sample during testing. In Comparative Examples 4-9, the lack of sufficient modification treatment of the functional fiber fabric layer led to fabric damage during rubbing of the flexible composite material, resulting in a significant decrease in the tensile strength of the material.

[0092] As shown in the table above, the flexible composite materials in Examples 1-18 exhibit good appearance and no damage after 1000 rubbing cycles, with a helium permeability of less than 0.5 L / m. 2 The flexible composite materials in Comparative Examples 1-9 exhibit air leakage due to the lack of a gas barrier layer or insufficient modification of the functional fiber fabric layer. Consequently, the flexible composite materials have poor resistance to rubbing and poor gas barrier properties.

[0093] In the description of this application, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are merely examples and can be any technical feature connected by "and / or" in this application.

[0094] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0095] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0096] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0097] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing flexible composite materials, characterized in that, include: Modify the fiber fabric to obtain a functionalized fiber fabric layer; A corona treatment is performed on one side of the weather-resistant film, and a first gas barrier layer is formed on the corona-treated side of the weather-resistant film through a first coating process to obtain a gas barrier weather-resistant film. A second gas barrier layer is formed on one side surface of the plastic film by a deposition process to obtain a gas barrier plastic film; The gas barrier weather-resistant film and the gas barrier plastic film are arranged opposite to each other, and the first gas barrier layer and the second gas barrier layer are bonded together using a first adhesive to obtain a first composite film; The first composite film is arranged opposite to the functional fiber fabric layer, and the plastic film is bonded to the functional fiber fabric layer using a second adhesive to obtain a second composite film; A heat-sealing layer is formed on the surface of the functionalized fiber fabric layer away from the plastic film by a second coating process to obtain the flexible composite material; The modification treatment includes immersing the fiber fabric in an immersion coating solution and then drying the immersion-coated fiber fabric. The dip coating solution comprises 1.5-25 parts by weight of grafting agent, 0.2-2.5 parts by weight of film-forming agent, 0.01-0.5 parts by weight of initiator and 20-2000 parts by weight of solvent. The grafting agent comprises at least one of propyl methacrylate triethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, γ-ureopropyltrimethoxysilane, γ-ureotriethoxysilane, γ-isocyanate-propyltrimethoxysilane, γ-isocyanate-triethoxysilane, tetraisopropoxytitanium, triisopropoxyaluminum, aluminum trichloride, titanium tetrachloride, and zirconium tetrachloride. The film-forming agent comprises a water-soluble polymer, which includes at least one of polyacrylamide, polyvinylpyrrolidone, polyacrylic acid, polymethacrylic acid, acrylic acid-methacrylic acid copolymer, polyvinyl alcohol, polyethyleneimine, polyethylene oxide, ethylene-vinyl alcohol copolymer, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, polysaccharides, chitosan, and cellulose. The flexible composite material comprises a weather-resistant film, a first gas barrier layer, a first adhesive layer, a second gas barrier layer, a plastic film, a second adhesive layer, a functionalized fiber fabric layer, and a heat-sealing layer, which are stacked sequentially. The functionalized fiber fabric layer includes a fiber fabric and a modifying substance, wherein the modifying substance is attached to the surface of the fiber fabric and the modifying substance includes an inorganic-organic hybrid polymer. The thickness of the fiber fabric is 30μm-250μm, and the areal density is 25g / m³. 2 -250g / m 2 ; The thickness of the first gas barrier layer is 0.1μm-2μm; the thickness of the second gas barrier layer is 10nm-100nm.

2. The method according to claim 1, characterized in that, The fiber fabric includes at least one of polyimide fiber fabric, poly(p-phenylenebisoxazole) fiber fabric, ultra-high molecular weight polyethylene fiber fabric, aromatic polyamide fiber fabric, aromatic polyester fiber fabric, aliphatic polyamide fiber fabric, and aliphatic polyester fiber fabric.

3. The method according to claim 1, characterized in that, The first gas barrier layer comprises at least one of an inorganic hybrid modified hydroxyl polymer and an inorganic hybrid modified carboxyl polymer, and the second gas barrier layer comprises a barrier layer material, wherein the barrier layer material comprises at least one of alumina, silicon oxide, silicon nitride, titanium oxide and zirconium oxide.

4. The method according to claim 1, characterized in that, The flexible composite material satisfies at least one of the following conditions: The thickness of the weather-resistant film is 8μm-35μm; The thickness of the plastic film is 6μm-25μm; The thickness of the heat-sealing layer is 20μm-50μm; The amount of adhesive applied to the first adhesive layer is 3g / m 2 -15g / m 2 ; The amount of adhesive applied to the second adhesive layer is 10 g / m². 2 -30g / m 2 .

5. The method according to claim 1, characterized in that, The dip-coating process takes 5-120 seconds, the drying process takes 80-135°C, and the drying time takes 2-3 minutes.

6. The method according to claim 1, characterized in that, The initiator includes at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate and azobisisovalerate, dopamine hydrochloride, azobisisobutyramidine hydrochloride, azobisisobutyramidoline hydrochloride, azobisisobutyramidoline and azobisisocyanovaleric acid.

7. The method according to claim 1, characterized in that, The solvent comprises a mixed solution of water and an alcohol, wherein the alcohol comprises at least one of methanol, ethanol, isopropanol, and n-propanol.

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