Heat insulation film as well as preparation method and application thereof

Abstract

The invention discloses a heat-insulating film and a preparation method and application thereof. The heat insulation film comprises a transparent base material film and a nanometer heat insulation layer, the nanometer heat insulation layer comprises a nanometer heat insulation material, and the nanometer heat insulation material comprises a nanometer metal core material and a passivation layer wrapping the outer side of at least part of the nanometer metal core material; wherein the nano metal core material is selected from at least one of metal nanowires, metal nanosheets or metal nanoparticles, and the passivation layer is selected from a resin layer and / or a metal oxide layer. The nano metal core material is adopted, so that the specific surface area is high, the infrared reflection effect is good, and the light transmittance is high; the passivation layer is coated on the outer side of the nano metal core material, so that the number of direct overlapping points between the nano metal core materials is reduced, the electric continuity of the nano heat insulation layer is reduced, and the impedance adjustable range of the nano heat insulation layer is further increased; the problem of influence on communication signals can be effectively solved on the premise of ensuring the heat insulation effect; and oxidation of the nano metal core material can be slowed down, and the performance stability of the heat insulation film is improved.

Description

Technical Field

[0001] The invention relates to a thermal insulation film, and in particular to a thermal insulation film and a preparation method and application thereof. Background Art

[0002] Thermal insulation films are usually used in vehicles, buildings and other fields. Their function is to block outdoor infrared rays, which not only prevents the entry of such rays that are harmful to the human body or may damage objects, but also reduces the heat generated by the sun to lower the temperature inside the room, thereby saving energy accordingly.

[0003] The manufacturing process of currently available thermal insulation films generally adopts multi-layer optical thin film coating technology, such as magnetron sputtering metal layer. The product manufacturing process is complicated and costly. Moreover, because it contains a metal layer, while the thermal insulation film blocks infrared rays, it will also cause a decrease in the transmittance of visible light to varying degrees, affecting the lighting effect of the interior room. At the same time, as time goes by, the metal layer is easily oxidized, and its reflectivity decreases, which will cause the barrier effect of the thermal insulation film to gradually weaken. In addition, due to the low impedance of the metal layer, the use of existing thermal insulation films makes it extremely easy to shield the communication signal in the interior room, resulting in weak signal strength in the interior room.

[0004] In view of this, it is necessary to improve the existing thermal insulation film and its preparation method and application to solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a thermal insulation film and a preparation method and application thereof, so as to solve at least one of the above-mentioned technical problems.

[0006] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0007] A thermal insulation film comprises: a transparent substrate film; a nano thermal insulation layer comprising a nano thermal insulation material, wherein the nano thermal insulation material comprises a nano metal core material and a passivation layer coated on the outside of at least a portion of the nano metal core material; wherein the nano metal core material is selected from at least one of metal nanowires, metal nanosheets or metal nanoparticles, and the passivation layer is selected from a resin layer and / or a metal oxide layer.

[0008] In one embodiment, the nanometal core material includes at least one of a metal single substance core material, a core-shell type metal core material, a doped metal compound core material or an alloy metal core material.

[0009] In one embodiment, the metal element core material is selected from one of gold, silver, copper, aluminum, tin, nickel, and germanium; and / or the core-shell metal core material is selected from at least one of silver-clad copper, gold-clad copper, and nickel-clad copper; and / or the doped metal compound core material is selected from at least one of cadmium sulfide, cadmium selenide, cadmium telluride, zinc selenide, lead sulfide, lead selenide, indium phosphide, or indium arsenide, and the doping element is selected from at least one of nitrogen, boron, and indium; and / or the alloy metal core material is selected from at least one of gold-silver alloy, platinum-palladium alloy, copper-nickel alloy, iron-platinum alloy, palladium-ruthenium alloy, silver-copper alloy, titanium-nickel alloy, and cobalt-iron alloy.

[0010] In one embodiment, the nanometal core material contains metal nanowires, and the wire diameter ratio of the metal nanowires is 50 to 5000; or, the nanometal core material contains metal nanosheets, and the surface size of the metal nanosheets is not greater than 100 μm and the thickness is not greater than 20 nm; or, the nanometal core material contains metal nanoparticles, and the diameter of the metal nanoparticles is not greater than 100 μm.

[0011] In one embodiment, the passivation layer is selected from a resin layer, or the passivation layer is selected from a resin layer and a metal oxide layer, the resin layer is transparent, and the resin layer is selected from at least one of polyester resin, polyurethane resin, acrylic resin or epoxy resin.

[0012] In one embodiment, the passivation layer is selected from a metal oxide layer, or the passivation layer is selected from a resin layer and a metal oxide layer, and the metal oxide layer is formed by oxidation of the nano metal core material.

[0013] In one embodiment, the passivation layer is selected from a resin layer and a metal oxide layer, the resin layer is transparent, and the resin layer is selected from at least one of polyester resin, polyurethane resin, acrylic resin or epoxy resin; the metal oxide layer is formed by oxidation of the nanometal core material.

[0014] In one embodiment, the light transmittance of the thermal insulation film is not less than 80%, the haze is not greater than 10%; and / or the infrared reflectivity is not less than 8%; and / or the resistivity of the nano thermal insulation layer is 3×10 -8 ~5×10 -6 Ω.m; and / or the mobile phone signal strength attenuation of the thermal insulation film is -30dB to 0dB.

[0015] In one embodiment, the thermal insulation film further includes an infrared absorption layer, which is disposed on at least one side of the nano thermal insulation layer, or the infrared absorption layer is disposed on at least one side of the transparent substrate film; and / or the thermal insulation film further includes an ultraviolet absorption layer, which is disposed on at least one side of the nano thermal insulation layer, or the ultraviolet absorption layer is disposed on any side of the transparent substrate film; and / or the thermal insulation film further includes a protective layer, which is located on a side of the thermal insulation film away from the transparent substrate film.

[0016] A method for preparing a thermal insulation film comprises the following steps: adding an oxidant and / or a resin solution to a dispersion of at least one of metal nanowires, metal nanosheets, and metal nanoparticles, and mixing to obtain a nano-metal dispersion; coating the nano-metal dispersion on one side of a transparent substrate film to obtain a composite film layer; heating the composite film layer at 60° C. to 140° C. to solidify the nano-metal dispersion to form a nano-insulation layer, and obtain a thermal insulation film; wherein at least one of the metal nanowires, metal nanosheets, and metal nanoparticles in the nano-metal dispersion constitutes a nano-metal core material, the resin in the resin solution is adsorbed on the surface of the nano-metal core material to form a passivation layer, and / or the oxidant oxidizes the surface of the nano-metal core material to form a passivation layer.

[0017] In one embodiment, the nano-metal dispersion contains a resin solution, and the mass ratio of the resin in the resin solution to the nano-metal core material is 1:10 to 10:1.

[0018] In one embodiment, the nano-metal dispersion contains an oxidant, the oxidant is hydrogen peroxide, and the mass ratio of hydrogen peroxide to the nano-metal core material is 20:1 to 1:1; or the oxidant is ozone, and the concentration is 2g / m 3 ~10g / m 3 Ozone is added into the dispersion of the nano-metal core material, and the time of introducing ozone is between 1 min and 60 min.

[0019] In one embodiment, adding the oxidant and the resin solution to the dispersion of the nanometal core material comprises: adding the oxidant first and then adding the resin solution.

[0020] In one embodiment, adding the oxidant and the resin solution to the dispersion of the nanometal core material comprises: adding the resin solution first and then adding the oxidant.

[0021] In one embodiment, the resin solution is only added to the dispersion of the nano-metal core material to obtain the thermal insulation film layer, and then the thermal insulation film layer is oxidized by hydrogen peroxide or ozone.

[0022] The application of the thermal insulation film as described above in vehicle window glass and building glass.

[0023] The beneficial effects of the present invention are as follows: the thermal insulation film of the present invention includes nano thermal insulation materials, wherein the nano metal core material has a high specific surface area and good infrared reflection effect; the passivation layer is coated on the outside of the nano metal core material, which reduces the number of direct overlap points between the nano metal core materials, reduces the electrical continuity of the nano thermal insulation layer, and thus increases the adjustable impedance range of the nano thermal insulation layer, which is specifically reflected in the adjustable resistivity; it can also effectively overcome the problem that the nano thermal insulation layer is easy to affect the communication signal under the premise of ensuring the infrared blocking effect (i.e., thermal insulation effect) of the thermal insulation film. In addition, the passivation layer can also slow down the oxidation of the nano metal core material and improve the performance stability of the thermal insulation film. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 SEM image of traditional silver nanowires

[0025] Figure 2 This is a SEM image of the silver nanowires wrapped with a passivation layer in the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below in conjunction with specific embodiments.

[0027] The present invention aims to provide a thermal insulation film which improves the light transmittance of the thermal insulation film while ensuring the infrared thermal insulation effect, and avoids the problem of communication signal shielding to the greatest extent.

[0028] The heat-insulating film comprises a transparent substrate film and a nano heat-insulating layer located on one side of the transparent substrate film.

[0029] The transparent substrate film is the basis of the thermal insulation film and can be a hard transparent film or a flexible transparent film, selected from but not limited to PET film, PI film and the like.

[0030] The nano heat insulation layer includes nano heat insulation materials for reflecting infrared rays, such as Figure 2 As shown, the nano thermal insulation material includes a nano metal core material and a passivation layer coated on at least a portion of the nano metal core material.

[0031] The nano metal core material has a high specific surface area and good infrared reflection effect; it is mainly used to reflect infrared rays and achieve a heat insulation effect. In the present invention, the nano metal core material is selected from but not limited to at least one of a metal single substance core material, a core-shell type metal core material, a doped metal compound core material or an alloy metal core material.

[0032] Wherein, the metal single substance core material is selected from but not limited to at least one of gold, silver, copper, aluminum, tin, nickel, and germanium. The core-shell type metal core material is selected from but not limited to at least one of silver-clad copper, gold-clad copper, and nickel-clad copper. The doped metal compound core material is selected from at least one of cadmium sulfide, cadmium selenide, cadmium telluride, zinc selenide, lead sulfide, lead selenide, indium phosphide, or indium arsenide, and the doping element is selected from at least one of nitrogen, boron, and indium. The alloy metal core material is selected from at least one of gold-silver alloy, platinum-palladium alloy, copper-nickel alloy, iron-platinum alloy, palladium-ruthenium alloy, silver-copper alloy, titanium-nickel alloy, and cobalt-iron alloy.

[0033] From the perspective of morphology, the nanometal core material refers to a material having at least one dimension of nanometer size, and its morphology is not limited and is selected from but not limited to: metal nanowires, metal nanosheets, metal nanoparticles, etc.

[0034] The wire diameter ratio (length / diameter) of the metal nanowire is 50 to 5000, preferably 100 to 2000, and more preferably 400 to 1500. In the present invention, the wire diameter of the metal nanowire is 5 nm to 500 nm, and preferably 10 nm to 50 nm.

[0035] In a preferred embodiment, the metal nanowire is a metal single substance nanowire, such as silver nanowire, copper nanowire, gold nanowire, nickel nanowire, etc. In another preferred embodiment, the metal nanowire is a core-shell nanowire, silver-coated copper nanowire, gold-coated copper nanowire, nickel-coated copper nanowire, etc. In another preferred embodiment, the metal nanowire is a doped nanowire, such as cadmium sulfide nanowire, cadmium selenide nanowire, cadmium telluride nanowire, zinc selenide nanowire, lead sulfide nanowire, lead selenide nanowire, indium phosphide nanowire or indium arsenide nanowire, etc. doped with at least one of nitrogen, boron and indium. In another preferred embodiment, the metal nanowire is an alloy nanowire, such as gold-silver alloy nanowire, platinum-palladium alloy nanowire, copper-nickel alloy nanowire, iron-platinum alloy nanowire, palladium-ruthenium alloy nanowire, silver-copper alloy nanowire, titanium-nickel alloy nanowire, cobalt-iron alloy nanowire, etc.

[0036] The metal nanosheet has a surface size of no more than 100 μm and a thickness of no more than 20 nm; preferably, the surface size diameter is no more than 50 μm and the thickness is no more than 10 nm; more preferably, the surface size diameter is no more than 5 μm and the thickness is no more than 5 nm. The metal nanosheet is made of any of the above nano metal core materials.

[0037] The diameter of the metal nanoparticles is not greater than 100 μm, preferably not greater than 10 μm, more preferably not greater than 1 μm, and further preferably metal quantum dots. The metal nanoparticles are made of any of the above-mentioned nanometal core materials.

[0038] In the present invention, the content of the nano thermal insulation core material in the nano thermal insulation layer is 0.01 g / m 2 ~0.5g / m 2 It can not only ensure a high infrared reflectivity and achieve heat insulation effect, but also ensure a high light transmittance and low haze without affecting indoor lighting.

[0039] “The passivation layer is coated on at least a portion of the nanometal core material” includes the following two situations: the passivation layer is coated on a portion of the nanometal core material or all of the nanometal core material, or the passivation layer is coated on a portion or all of the surface of the nanometal core material.

[0040] The passivation layer is coated on the outside of the nanometal core material, which reduces the number of direct overlap points between the nanometal core materials, reduces the electrical continuity of the nanothermal insulation layer, and thus increases the adjustable impedance range of the nanothermal insulation layer, which is specifically reflected in the adjustable resistivity; it can also effectively overcome the problem that the nanothermal insulation layer is easy to affect the communication signal while ensuring the infrared blocking effect (i.e., thermal insulation effect) of the thermal insulation film. In addition, the passivation layer can also slow down the oxidation of the nanometal core material and improve the performance stability of the thermal insulation film.

[0041] Preferably, the passivation layer is a resin layer, or the passivation layer is a metal oxide layer, or the passivation layer is a metal oxide layer and a resin layer.

[0042] The resin layer is preferably transparent and is selected from but not limited to at least one of polyester resin, polyurethane resin, acrylic resin or epoxy resin.

[0043] The polyester resin is selected from but not limited to Toyobo VYLONAL MD-1200.

[0044] The polyurethane resin is selected from but not limited to thermoplastic polyurethane (TPU), such as Mitsui Chemicals Takelac W-6110A.

[0045] The acrylic resin is selected from but not limited to acrylic (PMMA), such as BASF JONCRYL 678.

[0046] The epoxy resin is selected from but not limited to Sanmu SMW601G.

[0047] The metal oxide layer is formed by oxidation of the nano metal core material, specifically by oxidation with an oxidant such as hydrogen peroxide or ozone.

[0048] In addition, the thickness of the passivation layer is limited to less than 10 nanometers, which is relatively thin and has a weak reflection of infrared rays. After infrared rays penetrate the passivation layer, they will be reflected by the nano-metal core material, which basically does not affect the reflection of infrared rays by the entire film layer, but has a greater impact on electrical properties.

[0049] In the present invention, based on the nano metal core material and its passivation layer, the resistivity of the nano thermal insulation layer is 3×10 -8 ~5×10 -6 Ω.m; preferably, the resistivity of the nano thermal insulation layer is 3×10 -7 ~5×10 -6 Ω.m.

[0050] The cell phone signal strength attenuation of the thermal insulation film is -30dB to 0dB, preferably -20dB to 0dB, more preferably -10dB to 0dB. dB is the unit of signal strength, negative numbers mean attenuation, the closer to 0, the better the signal.

[0051] The light transmittance of the thermal insulation film is not less than 80%; the haze of the thermal insulation film is not greater than 10%, preferably not greater than 5%; the optical property of the thermal insulation film is good and does not affect the light inside the car or the room.

[0052] The infrared reflectivity of the thermal insulation film is not less than 8%, preferably not less than 10%.

[0053] It can be seen that the thermal insulation film reduces signal shielding while ensuring good optical properties and high infrared reflectivity.

[0054] Furthermore, the thermal insulation film further comprises an infrared absorption layer, and the infrared absorption layer is arranged on at least one side of the nano thermal insulation layer, or the infrared absorption layer is arranged on at least one side of the transparent substrate film.

[0055] The infrared absorption layer includes an infrared absorber for absorbing infrared rays, and the infrared absorber includes but is not limited to indium tin oxide, indium zinc oxide, antimony tin oxide, tungsten trioxide, aluminum-doped zinc oxide, and the like.

[0056] When the infrared absorption layer is located between the nano heat insulation layer and the transparent substrate film, or the infrared absorption layer is located on the side of the transparent substrate film away from the nano heat insulation layer; the infrared absorption layer is used to absorb the infrared rays that are not reflected by the nano heat insulation layer. When the infrared absorption layer is located on the side of the heat insulation film away from the transparent substrate film, the infrared rays are first absorbed to a certain extent before being reflected, further improving the infrared heat insulation performance of the heat insulation film.

[0057] Furthermore, the thermal insulation film further comprises an ultraviolet absorption layer, and the ultraviolet absorption layer is arranged on at least one side of the nano thermal insulation layer, or the ultraviolet absorption layer is arranged on any side of the transparent substrate film.

[0058] The ultraviolet absorption layer contains an ultraviolet absorber for absorbing ultraviolet rays. The ultraviolet absorber includes but is not limited to ZnO, CeO 2, benzophenone ultraviolet absorbers, benzimidazole ultraviolet absorbers or triazine ultraviolet absorbers, etc.

[0059] Adding the ultraviolet absorption layer to any layer of the thermal insulation film can prevent ultraviolet rays from passing through the thermal insulation film to avoid harm to the human body inside the room. For example, the ultraviolet absorption layer is located on the side of the nano thermal insulation layer away from the transparent substrate film, or the ultraviolet absorption layer is located between the nano thermal insulation layer and the transparent substrate film, or the infrared absorption layer is located on the side of the transparent substrate film away from the nano thermal insulation layer.

[0060] Preferably, the ultraviolet absorption layer is located on the light incident side of the thermal insulation film, for example, the side of the nano thermal insulation film away from the transparent substrate film, or the side of the transparent substrate film away from the nano thermal insulation layer; it can also delay the aging failure of the nano metal core material and reduce the aging effect of ultraviolet rays on the components in the transparent substrate film / nano thermal insulation layer.

[0061] Furthermore, the thermal insulation film also includes a protective layer, which is located on a side of the thermal insulation film away from the transparent substrate film, and together with the transparent substrate film, protects the internal film layer to prevent it from being scratched, worn, etc. during use.

[0062] The present invention also provides a method for preparing a thermal insulation film, comprising:

[0063] S1: preparing a nano-metal dispersion: adding an oxidant and / or a resin solution to a dispersion of a nano-metal core material, mixing, and stirring to obtain a nano-metal dispersion;

[0064] S2 coating the nano metal dispersion on one side of the transparent substrate film to obtain a composite film layer;

[0065] S3 heats the composite film layer to solidify the nano-metal dispersion to form a nano-insulation layer to obtain a thermal insulation film.

[0066] Among them, in step S1, the nanometal core material adopts any material described above, which will not be repeated here. In the dispersion of the nanometal core material, the concentration is related to the material of the nanometal core material and its dispersion properties, and can be adaptively adjusted according to the specific material. Usually, the content of the nanometal core material is 0.2% to 3%, and the rest is solvent.

[0067] The resin solution includes resin, surfactant, dispersant and solvent. The resin is used to be adsorbed on the surface of the nanometal core material to form a passivation layer, and is selected from at least one of polyester, polyurethane, acrylic resin or epoxy resin. The surfactant is used to improve wettability, surface adhesion and film-forming quality, and is selected from but not limited to at least one of nonionic, cationic, anionic surfactants and zwitterionic surfactants. The dispersant is used to improve the uniformity of dispersion in the coating liquid and the uniformity after film formation, and to prevent the agglomeration of the nanometal core material, and is selected from but not limited to at least one of cellulose, polyester resin, acrylic resin, polyurethane resin and modified materials thereof. The solvent is selected from but not limited to at least one of water, alcohols and DMF.

[0068] In the resin solution, the proportion of each component is adaptively adjusted according to the selected material to match the amount of the nanometal core material. After the dispersion of the nanometal core material is mixed with the resin solution, the weight ratio of the resin to the nanometal core material is 1:10 to 10:1. Preferably 1:4 to 10:1; more preferably 5:3 to 10:1, the electrical properties and optical properties are in a better state.

[0069] In a preferred embodiment, the nano-metal dispersion comprises, by mass percentage, 0.01% to 1% of nano-metal core material, 0.1% to 10% of resin, 0.001% to 1% of surfactant, 0.001% to 1% of dispersant, and the remainder is solvent.

[0070] During the stirring process, the resin is adsorbed on the surface of the nanometal through intermolecular forces (van der Waals forces) to form a passivation layer, such as Figure 2 shown.

[0071] The oxidant is a hydrogen peroxide solution with a mass concentration of less than 2%. After adding the nano-metal dispersion, the mass ratio of hydrogen peroxide to the nano-metal core material is 20:1 to 1:1: preferably 10:1 to 1:1. During the stirring and mixing process, the hydrogen peroxide oxidizes the surface of the nano-metal core material to form a passivation layer.

[0072] Or, the oxidant is ozone, which is added to the dispersion of the nanometal core material at a concentration of 2 g / m 3 ~10g / m 3 The ozone is introduced into 1L of the dispersion of the nanometal core material for a period of 1 min to 60 min. During the stirring and mixing process, the ozone oxidizes the surface of the nanometal core material to form a passivation layer.

[0073] When only the resin solution, hydrogen peroxide solution or ozone is added to the dispersion of the nanometal core material, the adding method is as described above. When the resin solution and the oxidant are added to the dispersion of the nanometal core material at the same time, it is preferred to first add the hydrogen peroxide solution or ozone to oxidize the nanometal core material according to the above method, and then add the resin solution to adsorb a layer of resin on the surface as a passivation layer to further improve the passivation effect. The resin solution can also be added first, and then the oxidant is added. The oxidant enters the surface of the nanometal core material from the gaps or voids of the adsorbed resin and oxidizes it, achieving a double passivation effect. Compared with adding the oxidant first and then the resin solution, the oxidation time needs to be doubled or more.

[0074] In step S2, the coating method includes but is not limited to scraping, rod coating or spraying. Unit area (m 2 ) The content of the nano metal core material on the transparent substrate film is 0.01g to 0.5g.

[0075] In step S3, the heating condition is 60°C to 140°C. If the temperature is too low, the drying time will be too long; if the temperature is too high, the product performance will be affected.

[0076] In step S1, if only the resin solution is added to the dispersion of the nanometal core material, the thermal insulation film is oxidized by an oxidant after step S3. The oxidant penetrates the gaps or voids of the resin and enters the surface of the nanometal core material to oxidize it, further improving the passivation effect.

[0077] The oxidant is hydrogen peroxide, and hydrogen peroxide with a mass fraction of 3% or less is dripped onto the thermal insulation film, reacted for 10 seconds to 30 seconds, and then washed and dried with deionized water.

[0078] The oxidant is ozone. The thermal insulation film is placed in an ozone atmosphere with an ozone concentration of 0.05 g / m 3 ~2g / m 3 , reaction time 1s to 600s.

[0079] The heat-insulating film of the present invention can be applied to vehicle windows and building glass, including but not limited to front windows, side windows, rear windows, skylights, etc. Specifically, the heat-insulating film is attached to the inner side of the target vehicle window or building glass through a transparent adhesive layer, preferably with the side where the nano heat-insulating layer is located facing outward, that is, the nano heat-insulating layer faces the vehicle window glass or building glass side.

[0080] Of course, in the embodiment including the ultraviolet absorption layer, the ultraviolet absorption layer is arranged at the outermost side, and the light first passes through the ultraviolet absorption layer and then enters into other film layers.

[0081] The following will provide specific examples to describe the thermal insulation film of the present invention and its performance in detail as shown in Table 1. In the examples and comparative examples, the substrate is PET, and the unit area (m2 ) The content of the nano metal core material on the transparent substrate film is 0.05 g / m 2 .

[0082] It can be seen from Table 1 that when a resin passivation layer is formed on the surface of the nanometal core material, the infrared reflectivity is slightly reduced. When the resin content: nanometal core material content is not higher than 10:1, the infrared reflection effect can basically meet the requirements.

[0083] Under the premise of a certain metal nanowire content, as the resin ratio increases, the resistivity of the thermal insulation film increases, the signal shielding performance weakens, and the mobile phone signal attenuation decreases.

[0084] Table 1

[0085]

[0086]

[0087] In addition, based on Example 6, the thermal insulation film was placed in a concentration of 1 g / m 3 The measured data are shown in Table 2. After ozone treatment, the infrared reflection effect does not change much, but the attenuation of mobile phone signals is greatly reduced, indicating that the oxidation treatment of the nano-metal core material can also reduce the attenuation of mobile phone signals while ensuring the infrared reflectivity.

[0088] Table 2

[0089] Processing Infrared reflectivity -% Mobile phone signal attenuation-dB Example 6 11.75 -21 Ozone treatment 30S 11.62 -19 Ozone treatment 90S 11.49 -15

[0090] In summary, the thermal insulation film of the present invention includes nano thermal insulation materials, wherein the nano metal core material has a high specific surface area, good infrared reflection effect, and high light transmittance; the passivation layer is coated on the outside of the nano metal core material, which reduces the number of direct overlap points between the nano metal core materials, reduces the electrical continuity of the nano thermal insulation layer, and thus increases the adjustable impedance range of the nano thermal insulation layer, which is specifically reflected in the adjustable resistivity; it can also effectively overcome the problem that the nano thermal insulation layer is easy to affect the communication signal while ensuring the infrared blocking effect (i.e., thermal insulation effect) of the thermal insulation film; in addition, the passivation layer can also slow down the oxidation of the nano metal core material and improve the performance stability of the thermal insulation film. The entire thermal insulation film has good thermal insulation performance and light transmittance.

[0091] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A thermal insulation film, characterized in that: include: Transparent substrate film; The nano thermal insulation layer comprises a nano thermal insulation material, wherein the nano thermal insulation material comprises a nano metal core material and a passivation layer coated on at least a portion of the outer side of the nano metal core material; Wherein, the nano metal core material is selected from at least one of metal nanowires, metal nanosheets or metal nanoparticles, and the passivation layer is selected from a resin layer and / or a metal oxide layer.

2. The thermal insulation film according to claim 1, characterized in that: The nano metal core material comprises at least one of a metal single substance core material, a core-shell type metal core material, a doped metal compound core material or an alloy metal core material; The metal core material is selected from one of gold, silver, copper, aluminum, tin, nickel and germanium; The core-shell metal core material is selected from at least one of silver-clad copper, gold-clad copper, and nickel-clad copper; The doped metal compound core material is selected from at least one of cadmium sulfide, cadmium selenide, cadmium telluride, zinc selenide, lead sulfide, lead selenide, indium phosphide or indium arsenide, and the doping element is selected from at least one of nitrogen, boron, indium, etc.; The alloy metal core material is selected from at least one of gold-silver alloy, platinum-palladium alloy, copper-nickel alloy, iron-platinum alloy, palladium-ruthenium alloy, silver-copper alloy, titanium-nickel alloy and cobalt-iron alloy.

3. The thermal insulation film according to claim 1, characterized in that: The nanometal core material contains metal nanowires, and the wire diameter ratio of the metal nanowires is 50 to 5000; Or, the nanometal core material contains metal nanosheets, the surface size of the metal nanosheets is not greater than 100 μm, and the thickness is not greater than 20 nm; Alternatively, the nano-metal core material contains metal nano-particles, and the diameter of the metal nano-particles is no greater than 100 μm.

4. The thermal insulation film according to claim 1, characterized in that: The passivation layer is selected from a resin layer, or the passivation layer is selected from a resin layer and a metal oxide layer, the resin layer is transparent, and the resin layer is selected from at least one of polyester resin, polyurethane resin, acrylic resin or epoxy resin; Or, the passivation layer is selected from a metal oxide layer, or the passivation layer is selected from a resin layer and a metal oxide layer, and the metal oxide layer is formed by oxidation of the nano metal core material; Alternatively, the passivation layer is selected from a resin layer and a metal oxide layer, the resin layer is transparent, and the resin layer is selected from at least one of polyester resin, polyurethane resin, acrylic resin or epoxy resin; and the metal oxide layer is formed by oxidation of the nanometal core material.

5. The thermal insulation film according to claim 1, characterized in that: The light transmittance of the thermal insulation film is not less than 80%, and the haze is not greater than 10%; and / or Infrared reflectivity not less than 8%; and / or The resistivity of the nano thermal insulation layer is 3×10 -8 ~5×10 -6 Ω.m; and / or The mobile phone signal strength attenuation of the thermal insulation film is -30dB to 0dB.

6. The thermal insulation film according to claim 1, characterized in that: The thermal insulation film further comprises an infrared absorption layer, wherein the infrared absorption layer is disposed on at least one side of the nano thermal insulation layer, or the infrared absorption layer is disposed on at least one side of the transparent substrate film; And / or, the thermal insulation film further comprises an ultraviolet absorption layer, and the ultraviolet absorption layer is arranged on at least one side of the nano thermal insulation layer, or the ultraviolet absorption layer is arranged on any side of the transparent substrate film; And / or, the thermal insulation film further includes a protective layer, and the protective layer is located on a side of the thermal insulation film away from the transparent substrate film.

7. A method for preparing a thermal insulation film, characterized in that: The steps include: Adding an oxidant and / or a resin solution to a dispersion of at least one of metal nanowires, metal nanosheets, and metal nanoparticles, and mixing to obtain a nano-metal dispersion; coating the nano-metal dispersion on one side of the transparent substrate film to obtain a composite film layer; The composite film layer is heated at 60° C. to 140° C. to solidify the nano-metal dispersion to form a nano-insulation layer, thereby obtaining an insulation film; Among them, at least one of the metal nanowires, metal nanosheets, and metal nanoparticles in the nano-dispersion liquid constitutes a nano-metal core material, the resin in the resin solution is adsorbed on the surface of the nano-metal core material to form a passivation layer, and / or the oxidant oxidizes the surface of the nano-metal core material to form a passivation layer.

8. The method for preparing the thermal insulation film according to claim 7, characterized in that: The nano-metal dispersion contains a resin solution, and the mass ratio of the resin in the resin solution to the nano-metal core material is 1:10 to 10:1; Or, the nano-metal dispersion contains an oxidant, the oxidant is hydrogen peroxide, and the mass ratio of hydrogen peroxide to the nano-metal core material is 20:1 to 1:1; or the oxidant is ozone, and the concentration is 2g / m 3 ~10g / m 3 Ozone is added into the dispersion of the nano-metal core material, and the time of introducing ozone is between 1 min and 60 min.

9. The method for preparing a thermal insulation film according to claim 7, characterized in that: Adding an oxidant and a resin solution to the dispersion of the nano metal core material comprises: first adding the oxidant and then adding the resin solution; Or, adding the oxidant and the resin solution to the dispersion of the nano metal core material comprises: first adding the resin solution and then adding the oxidant; Alternatively, only the resin solution is added to the dispersion of the nano-metal core material to obtain the thermal insulation film layer, and then the thermal insulation film layer is oxidized by hydrogen peroxide or ozone.

10. Use of the thermal insulation film according to any one of claims 1 to 6 in vehicle window glass and building glass.

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