A gray infrared low-radiation flexible film with high radar wave transmittance

Abstract

The present invention relates to the field of infrared functional materials, and specifically discloses a gray infrared low-radiation flexible film with high radar wave transmittance. The present invention is composed of a flexible polyester film, a transition layer coating, a first dielectric layer, a polymer layer, a second dielectric layer, and a gray coating, and has the characteristics of an average emissivity of ≤0.3 in the infrared band of 8μm to 14μm, a radar wave transmittance of ≥90% in the bands of 8Ghz to 18Ghz and 30GHz to 40GHz, good flexibility and weather resistance, etc.

Description

Technical Field

[0001] The invention relates to the field of infrared functional materials, and in particular to a gray infrared low-radiation flexible film with high radar wave transmittance. Background Art

[0002] Multi-band compatible stealth is an important means for weapons and equipment to improve their stealth and penetration capabilities. Tanks and other weapons and equipment require visible light, infrared, and radar multi-band compatible stealth capabilities. Visible light stealth and infrared stealth require the ability to blend into the background. Visible light stealth is mainly achieved through camouflage patterns, and infrared stealth is achieved by reducing the infrared radiation rate of the target; radar stealth requires high radar wave absorption and low reflection capabilities. However, existing stealth materials have many technical difficulties in multi-band compatibility.

[0003] At present, the materials with low infrared radiation performance include infrared stealth coating, metal film, semiconductor film, metal array structure, one-dimensional photonic crystal, etc. Among them, infrared stealth coating, metal film, semiconductor film, metal array structure all use the high reflection effect of metal materials or semiconductor materials on infrared light to suppress infrared radiation. The high-density free carriers in metal materials and semiconductor materials have a strong shielding effect on radar waves. Therefore, the above stealth materials cannot penetrate radar waves and are not compatible with radar stealth.

[0004] The reflection spectrum of one-dimensional photonic crystals is designable. By adjusting the structural parameters of one-dimensional photonic crystals to make the photon bandgap in the infrared band, the transmission of infrared light in the one-dimensional photonic crystal can be suppressed to achieve low infrared radiation. Zhixun Wang et al. (Journal of Applied Physics, 2014, 116, 054905) reported a one-dimensional photonic crystal structure infrared stealth material composed of alternating germanium and zinc sulfide. The infrared radiation rate of 3μm to 5μm is 0.073, the infrared radiation rate of 8μm to 12μm is 0.042, and the transmittance is high in the radar band of 2GHz to 18GHz. Qi Dong et al. (Dong Qi, Xian Wang, Yongzhi Cheng, Rongzhou Gong, Bowen L, Optical Materials, 2016, 62, 52-56) used smooth quartz glass as a substrate to prepare a visible-infrared compatible stealth film, which is composed of a composite film of ZnS and Ge with different structures and a surface TiO2 film. Through the matching of the structure and thickness of the three, different colors such as khaki, gray-green, and blue are displayed. The one-dimensional photonic crystals studied in the early stage are all composed of dielectric materials with different refractive indices. When different dielectric materials are matched, lattice constants, thermal expansion coefficients, and stress mismatches are prone to occur, resulting in failures such as high stress, high brittleness, easy cracking, and easy falling off in the multilayer dielectric film. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a gray infrared low-radiation flexible film with high radar wave transmittance in response to the infrared stealth requirements compatible with radar, which also has the characteristics of low infrared emissivity, high radar wave transmittance, good flexibility and weather resistance.

[0006] The purpose of the present invention is achieved by using a flexible polyester film as a substrate, coating a transition layer on the surface of the flexible substrate by a precision coating process, depositing a first dielectric layer on the surface of the transition layer by a vacuum evaporation process, coating a polymer layer on the surface of the first dielectric layer by a precision coating process, depositing a second dielectric layer on the surface of the polymer layer by a vacuum evaporation process, and coating a gray coating on the surface of the inorganic non-metallic material layer. The good matching of the transition layer coating with the substrate and the dielectric layer is used to achieve firm adhesion of the dielectric layer; a sandwich structure is formed by two dielectric layers and one polymer layer, and the sandwich structure is used to achieve infrared high reflection and low radiation performance by using the interference effect of infrared light; a surface gray coating is used to achieve visible light stealth performance; the substrate, polymer layer, and surface coating are used to divide and protect the dielectric layer to achieve good flexibility of the infrared stealth film; in the entire film structure, there is no material with high loss to radar waves, ensuring high radar wave transmittance.

[0007] The invention provides a gray infrared low-radiation flexible film with high radar wave transmittance, which consists of a flexible polyester film, a transition layer coating, a first dielectric layer, a polymer layer, a second dielectric layer and a gray coating.

[0008] Furthermore, the flexible polyester film is one of a polyethylene terephthalate film and a polyimide film, and the thickness of the flexible polyester film is between 50 μm and 200 μm.

[0009] Furthermore, the transition layer coating is a polyurethane acrylic coating. The material system of the polyurethane acrylic coating does not contain pigments and fillers, and is formed by mixing polyurethane acrylic varnish with a proper amount of solvent and a proper amount of initiator and applying the coating using a precision coating process. The thickness of the transition layer coating is 10 μm to 15 μm.

[0010] Furthermore, the first dielectric layer is one of a germanium film and a silicon film, and the thickness of the film layer is 0.7 μm to 0.9 μm.

[0011] Furthermore, the polymer layer is a polystyrene layer. The material system of the polystyrene layer does not contain pigments and fillers, and is formed by dispersing polystyrene resin in xylene solvent and coating it using a precision coating process. The thickness of the polystyrene layer is 1.3 μm to 1.6 μm.

[0012] Furthermore, the second dielectric layer is one of a germanium film and a tellurium film, and the thickness of the film layer is 0.5 μm to 0.7 μm.

[0013] Furthermore, the gray coating is formed by uniformly mixing gray paint with an appropriate amount of diluent and an appropriate amount of curing agent, and then coating the gray coating using a precision coating process. The thickness of the gray coating is between 2 μm and 3 μm.

[0014] Furthermore, the mass composition of the gray paint includes at least:

[0015] Polymer resin, 100 solid parts;

[0016] Nano-grade titanium dioxide, 10-20 parts;

[0017] Nano carbon black, 5-10 parts;

[0018] Furthermore, the polymer resin is one of fluorocarbon resin and polyurethane resin.

[0019] Compared with the prior art, the gray infrared low-radiation flexible film with high radar wave transmittance proposed by the present invention has the characteristics of average emissivity ≤0.3 in the infrared band of 8μm to 14μm, radar wave transmittance ≥90% in the bands of 8Ghz to 18Ghz and 30GHz to 40GHz, good flexibility and weather resistance, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the infrared reflection spectrum of the gray infrared low-radiation flexible film with high radar wave transmittance of Example 1. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below by means of embodiments, but is not intended to limit the protection scope of the present invention.

[0022] In all the following examples, the infrared radiation rate of the material samples was tested by an infrared emissivity measuring instrument; the radar wave transmittance was tested by a network analyzer.

[0023] Embodiment 1

[0024] A polyethylene terephthalate film having a thickness of 50 μm was used as the substrate.

[0025] The polyurethane acrylic varnish is mixed with a proper amount of solvent and a proper amount of initiator to obtain a transition layer coating liquid, and the transition layer coating liquid is coated on the surface of the substrate by a precision coating process to obtain a 10 μm thick transition layer coating.

[0026] A 0.9 μm germanium film is deposited on the surface of the transition layer coating by a vacuum evaporation process to obtain a first dielectric layer.

[0027] The polystyrene resin is dispersed in a proper amount of xylene solvent to obtain a polymer layer coating liquid, and the coating liquid is coated on the surface of the first dielectric layer using a precision coating process to obtain a 1.3 μm thick polymer layer.

[0028] A 0.5 μm tellurium film is deposited on the surface of the polymer layer by a vacuum evaporation process to obtain a second dielectric layer.

[0029] 100 solid parts of fluorocarbon resin are mixed evenly with 10 parts of nano-grade titanium dioxide, 5 parts of nano-grade carbon black, an appropriate amount of diluent, and an appropriate amount of additive to obtain a gray coating. The gray coating is mixed evenly with an appropriate amount of diluent and an appropriate amount of curing agent to obtain a gray coating liquid. The gray coating liquid is applied to the surface of the substrate using a precision coating process to obtain a 2 μm thick gray coating.

[0030] The gray infrared low-radiation flexible film with high radar wave transmittance has an average emissivity of 0.18 in the 8μm to 14μm infrared band and a minimum transmittance of 94% in the 8Ghz to 18Ghz and 30GHz to 40GHz radar wave bands.

[0031] Attached Figure 1 It is the infrared reflection spectrum of gray infrared low-radiation flexible film with high transmittance of radar waves.

[0032] Embodiment 2

[0033] A polyimide film with a thickness of 200 μm was used as the substrate.

[0034] The polyurethane acrylic varnish is mixed with a proper amount of solvent and a proper amount of initiator to obtain a transition layer coating liquid, and the transition layer coating liquid is coated on the surface of the substrate by a precision coating process to obtain a 12 μm thick transition layer coating.

[0035] A 0.8 μm germanium film is deposited on the surface of the transition layer coating by a vacuum evaporation process to obtain a first dielectric layer.

[0036] The polystyrene resin is dispersed in a proper amount of xylene solvent to obtain a polymer layer coating liquid, and the coating liquid is coated on the surface of the first dielectric layer using a precision coating process to obtain a 1.4 μm thick polymer layer.

[0037] A 0.6 μm tellurium film is deposited on the surface of the polymer layer by a vacuum evaporation process to obtain a second dielectric layer.

[0038] 100 solid parts of fluorocarbon resin are mixed evenly with 15 parts of nano-grade titanium dioxide, 7 parts of nano-grade carbon black, an appropriate amount of diluent, and an appropriate amount of additive to obtain a gray coating; the gray coating is mixed evenly with an appropriate amount of diluent and an appropriate amount of curing agent to obtain a gray coating liquid; the gray coating liquid is applied to the surface of the substrate using a precision coating process to obtain a 2 μm thick gray coating.

[0039] The gray infrared low-radiation flexible film with high radar wave transmittance has an average emissivity of 0.15 in the 8μm to 14μm infrared band and a minimum transmittance of 93% in the 8Ghz to 18Ghz and 30GHz to 40GHz radar wave bands.

[0040] Embodiment 3

[0041] A polyimide film with a thickness of 100 μm was used as the substrate.

[0042] The polyurethane acrylic varnish is mixed with a proper amount of solvent and a proper amount of initiator to obtain a transition layer coating liquid, and the transition layer coating liquid is coated on the surface of the substrate by a precision coating process to obtain a 15 μm thick transition layer coating.

[0043] A 0.7 μm germanium film is deposited on the surface of the transition layer coating by a vacuum evaporation process to obtain a first dielectric layer.

[0044] The polystyrene resin is dispersed in a proper amount of xylene solvent to obtain a polymer layer coating liquid, and the coating liquid is coated on the surface of the first dielectric layer using a precision coating process to obtain a 1.5 μm thick polymer layer.

[0045] A 0.7 μm germanium film is deposited on the surface of the polymer layer by a vacuum evaporation process to obtain a second dielectric layer.

[0046] 100 solid parts of fluorocarbon resin are mixed evenly with 20 parts of nano-grade titanium dioxide, 10 parts of nano-grade carbon black, an appropriate amount of diluent, and an appropriate amount of additive to obtain a gray coating. The gray coating is mixed evenly with an appropriate amount of diluent and an appropriate amount of curing agent to obtain a gray coating liquid. The gray coating liquid is applied to the surface of the substrate using a precision coating process to obtain a 2 μm thick gray coating.

[0047] The gray infrared low-radiation flexible film with high radar wave transmittance has an average emissivity of 0.25 in the 8μm to 14μm infrared band and a minimum transmittance of 95% in the 8Ghz to 18Ghz and 30GHz to 40GHz radar wave bands.

[0048] Embodiment 4

[0049] A polyimide film with a thickness of 150 μm was used as the substrate.

[0050] The polyurethane acrylic varnish is mixed with a proper amount of solvent and a proper amount of initiator to obtain a transition layer coating liquid, and the transition layer coating liquid is coated on the surface of the substrate by a precision coating process to obtain a 10 μm thick transition layer coating.

[0051] A 0.8 μm germanium film is deposited on the surface of the transition layer coating by a vacuum evaporation process to obtain a first dielectric layer.

[0052] The polystyrene resin is dispersed in a proper amount of xylene solvent to obtain a polymer layer coating liquid, and the coating liquid is coated on the surface of the first dielectric layer using a precision coating process to obtain a 1.6 μm thick polymer layer.

[0053] A 0.6 μm germanium film is deposited on the surface of the polymer layer by a vacuum evaporation process to obtain a second dielectric layer.

[0054] 100 solid parts of fluorocarbon resin are mixed evenly with 10 parts of nano-grade titanium dioxide, 10 parts of nano-grade carbon black, an appropriate amount of diluent, and an appropriate amount of additive to obtain a gray coating; the gray coating is mixed evenly with an appropriate amount of diluent and an appropriate amount of curing agent to obtain a gray coating liquid; the gray coating liquid is applied to the surface of the substrate using a precision coating process to obtain a 2 μm thick gray coating.

[0055] The gray infrared low-radiation flexible film with high radar wave transmittance has an average emissivity of 0.22 in the 8μm to 14μm infrared band and a minimum transmittance of 93% in the 8Ghz to 18Ghz and 30GHz to 40GHz radar wave bands.

[0056] Embodiment 5

[0057] A polyimide film with a thickness of 50 μm was used as the substrate.

[0058] The polyurethane acrylic varnish is mixed with a proper amount of solvent and a proper amount of initiator to obtain a transition layer coating liquid, and the transition layer coating liquid is coated on the surface of the substrate by a precision coating process to obtain a 12 μm thick transition layer coating.

[0059] A 0.9 μm silicon film is deposited on the surface of the transition layer coating by a vacuum evaporation process to obtain a first dielectric layer.

[0060] The polystyrene resin is dispersed in a proper amount of xylene solvent to obtain a polymer layer coating liquid, and the coating liquid is coated on the surface of the first dielectric layer using a precision coating process to obtain a 1.3 μm thick polymer layer.

[0061] A 0.5 μm germanium film is deposited on the surface of the polymer layer by a vacuum evaporation process to obtain a second dielectric layer.

[0062] 100 solid parts of polyurethane resin are mixed evenly with 15 parts of nano-grade titanium dioxide, 8 parts of nano-grade carbon black, an appropriate amount of diluent, and an appropriate amount of additive to obtain a gray coating. The gray coating is mixed evenly with an appropriate amount of diluent and an appropriate amount of curing agent to obtain a gray coating liquid. The gray coating liquid is applied to the surface of the substrate using a precision coating process to obtain a 3 μm thick gray coating.

[0063] The gray infrared low-radiation flexible film with high radar wave transmittance has an average emissivity of 0.27 in the 8μm to 14μm infrared band and a minimum transmittance of 91% in the 8Ghz to 18Ghz and 30GHz to 40GHz radar wave bands.

[0064] Embodiment 6

[0065] A polyethylene terephthalate film having a thickness of 200 μm was used as the substrate.

[0066] The polyurethane acrylic varnish is mixed with a proper amount of solvent and a proper amount of initiator to obtain a transition layer coating liquid, and the transition layer coating liquid is coated on the surface of the substrate by a precision coating process to obtain a 15 μm thick transition layer coating.

[0067] A 0.8 μm silicon film is deposited on the surface of the transition layer coating by a vacuum evaporation process to obtain a first dielectric layer.

[0068] The polystyrene resin is dispersed in a proper amount of xylene solvent to obtain a polymer layer coating liquid, and the coating liquid is coated on the surface of the first dielectric layer using a precision coating process to obtain a 1.4 μm thick polymer layer.

[0069] A 0.6 μm germanium film is deposited on the surface of the polymer layer by a vacuum evaporation process to obtain a second dielectric layer.

[0070] 100 solid parts of polyurethane resin are mixed evenly with 20 parts of nano-grade titanium dioxide, 7 parts of nano-grade carbon black, an appropriate amount of diluent, and an appropriate amount of additive to obtain a gray coating. The gray coating is mixed evenly with an appropriate amount of diluent and an appropriate amount of curing agent to obtain a gray coating liquid. The gray coating liquid is applied to the surface of the substrate using a precision coating process to obtain a 3 μm thick gray coating.

[0071] The gray infrared low-radiation flexible film with high radar wave transmittance has an average emissivity of 0.25 in the 8μm to 14μm infrared band and a minimum transmittance of 92% in the 8Ghz to 18Ghz and 30GHz to 40GHz radar wave bands.

[0072] Embodiment 7

[0073] A polyethylene terephthalate film having a thickness of 100 μm was used as the substrate.

[0074] The polyurethane acrylic varnish is mixed with a proper amount of solvent and a proper amount of initiator to obtain a transition layer coating liquid, and the transition layer coating liquid is coated on the surface of the substrate by a precision coating process to obtain a 10 μm thick transition layer coating.

[0075] A 0.7 μm silicon film is deposited on the surface of the transition layer coating by a vacuum evaporation process to obtain a first dielectric layer.

[0076] The polystyrene resin is dispersed in a proper amount of xylene solvent to obtain a polymer layer coating liquid, and the coating liquid is coated on the surface of the first dielectric layer using a precision coating process to obtain a 1.5 μm thick polymer layer.

[0077] A 0.7 μm tellurium film is deposited on the surface of the polymer layer by a vacuum evaporation process to obtain a second dielectric layer.

[0078] 100 solid parts of polyurethane resin are mixed evenly with 10 parts of nano-grade titanium dioxide, 6 parts of nano-grade carbon black, an appropriate amount of diluent, and an appropriate amount of additive to obtain a gray coating. The gray coating is mixed evenly with an appropriate amount of diluent and an appropriate amount of curing agent to obtain a gray coating liquid. The gray coating liquid is applied to the surface of the substrate using a precision coating process to obtain a 3 μm thick gray coating.

[0079] The gray infrared low-radiation flexible film with high radar wave transmittance has an average emissivity of 0.23 in the 8μm to 14μm infrared band and a minimum transmittance of 90% in the 8Ghz to 18Ghz and 30GHz to 40GHz radar wave bands.

[0080] Embodiment 8

[0081] A polyethylene terephthalate film having a thickness of 150 μm was used as the substrate.

[0082] The polyurethane acrylic varnish is mixed with a proper amount of solvent and a proper amount of initiator to obtain a transition layer coating liquid, and the transition layer coating liquid is coated on the surface of the substrate by a precision coating process to obtain a 12 μm thick transition layer coating.

[0083] A 0.8 μm silicon film is deposited on the surface of the transition layer coating by a vacuum evaporation process to obtain a first dielectric layer.

[0084] The polystyrene resin is dispersed in a proper amount of xylene solvent to obtain a polymer layer coating liquid, and the coating liquid is coated on the surface of the first dielectric layer using a precision coating process to obtain a 1.6 μm thick polymer layer.

[0085] A 0.6 μm tellurium film is deposited on the surface of the polymer layer by a vacuum evaporation process to obtain a second dielectric layer.

[0086] 100 solid parts of polyurethane resin are mixed evenly with 15 parts of nano-grade titanium dioxide, 5 parts of nano-grade carbon black, an appropriate amount of diluent, and an appropriate amount of additive to obtain a gray coating. The gray coating is mixed evenly with an appropriate amount of diluent and an appropriate amount of curing agent to obtain a gray coating liquid. The gray coating liquid is applied to the surface of the substrate using a precision coating process to obtain a 3 μm thick gray coating.

[0087] The gray infrared low-radiation flexible film with high radar wave transmittance has an average emissivity of 0.2 in the 8μm to 14μm infrared band and a minimum transmittance of 92% in the 8Ghz to 18Ghz and 30GHz to 40GHz radar wave bands.

Claims

1. A gray infrared low-radiation flexible film with high radar wave transmittance, characterized in that: It is composed of a flexible polyester film, a transition layer coating, a first dielectric layer, a polymer layer, a second dielectric layer, and a gray coating in sequence; The first dielectric layer is one of a germanium film and a silicon film, and the film thickness is 0.7 μm to 0.9 μm; The polymer layer is a polystyrene layer; The material system of the polystyrene layer does not contain pigments and fillers, and is obtained by dispersing polystyrene resin in xylene solvent and coating it using a precision coating process; the thickness of the polystyrene layer is 1.3 μm to 1.6 μm; The second dielectric layer is one of a germanium film and a tellurium film, and the thickness of the film layer is 0.5 μm to 0.7 μm.

2. The gray infrared low-radiation flexible film with high radar wave transmittance according to claim 1, characterized in that: The flexible polyester film is one of a polyethylene terephthalate film and a polyimide film; the thickness of the flexible polyester film is between 50 μm and 200 μm.

3. The gray infrared low-radiation flexible film with high radar wave transmittance according to claim 1, characterized in that: The transition layer coating is a polyurethane acrylic coating.

4. The gray infrared low-radiation flexible film with high radar wave transmittance according to claim 3, characterized in that: The material system of the polyurethane acrylic coating does not contain pigments and fillers, and is formed by mixing polyurethane acrylic varnish with a proper amount of solvent and a proper amount of initiator and coating them using a precision coating process; the thickness of the transition layer coating is 10 μm to 15 μm.

5. The gray infrared low-radiation flexible film with high radar wave transmittance according to claim 1, characterized in that: The gray coating is formed by uniformly mixing gray paint with a proper amount of diluent and a proper amount of curing agent, and then coating the mixture using a precision coating process; the thickness of the gray coating is between 2 μm and 3 μm.

6. The gray infrared low-radiation flexible film with high radar wave transmittance according to claim 5, characterized in that: The mass composition of the gray paint includes at least: Polymer resin, 100 solid parts; Nano-grade titanium dioxide, 10-20 parts; Nano carbon black, 5-10 parts; The polymer resin is one of fluorocarbon resin and polyurethane resin.

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