A self-warming thermal insulation window film with light-heat conversion performance and a preparation method thereof

Abstract

The application belongs to the technical field of thermal insulation window film, and relates to a self-warming thermal insulation window film with light-heat conversion performance and a preparation method thereof.The self-warming thermal insulation window film with light-heat conversion performance comprises, in sequence, a self-warming polyurethane coating layer, a first thermal insulation layer, a core layer, a second thermal insulation layer and a bonding layer; the self-warming polyurethane coating layer is prepared from Prussian blue composite polyurethane coating liquid; the addition amount of Prussian blue nanoparticles in the Prussian blue composite polyurethane coating liquid is 0.1-10 wt%; and the average particle size of the Prussian blue nanoparticles is 10-50 nm.The self-warming thermal insulation window film with light-heat conversion performance can absorb near-infrared light to increase temperature and keep warm under sunlight, and can reduce heat transfer to the outside at night, thereby greatly reducing the energy consumption for heating in high-latitude areas.

Description

Technical Field

[0001] This invention belongs to the field of thermal insulation window film technology, and relates to a self-heating thermal insulation window film with photothermal conversion properties and its preparation method. Background Technology

[0002] In winter, the sun's altitude angle is low, the daylight hours are short, and less solar radiation is received, resulting in lower temperatures. High-latitude regions, in particular, often face extreme weather conditions due to their unique geographical location. While summer brings a higher sun altitude angle and longer daylight hours, temperatures in high-latitude regions are still significantly lower than in low-latitude regions due to their climatic characteristics.

[0003] Windows are an essential component of residential buildings, but they are also the weakest point in terms of thermal insulation. Windows are made of materials such as glass, which have a high thermal conductivity, allowing heat to dissipate easily and resulting in relatively weak insulation performance. Therefore, residents often use window film to supplement insulation. Currently, most window films on the market focus on heat insulation, while window films designed for the insulation needs of high-latitude regions are rare, and most window films can only provide heat insulation and cannot meet the required requirements. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a self-heating and heat-insulating window film with photothermal conversion properties, which can rapidly heat up and effectively retain heat under sunlight.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A self-heating heat-insulating window film with photothermal conversion properties comprises, in sequence: a self-heating polyurethane coating, a first heat-insulating layer, a core layer, a second heat-insulating layer, and an adhesive layer; the self-heating polyurethane coating is prepared by a Prussian blue composite polyurethane coating solution; the amount of Prussian blue nanoparticles added to the Prussian blue composite polyurethane coating solution is 0.1~10wt%; the average particle size of the Prussian blue nanoparticles is 10~50nm.

[0007] Preferably, the amount of Prussian blue nanoparticles added to the Prussian blue composite polyurethane coating liquid is 0.1~5wt%.

[0008] Further preferably, the amount of Prussian blue nanoparticles added to the Prussian blue composite polyurethane coating liquid is 0.1~0.9wt%.

[0009] Preferably, the thickness ratio of the self-heating polyurethane coating, the first insulation layer, the core layer and the second insulation layer is (1~10):(20~50):(200~500):(20~50).

[0010] Preferably, a release layer is also provided on the other side of the adhesive layer.

[0011] Preferably, the raw materials of the Prussian blue composite polyurethane coating liquid include: 100-1000 parts of waterborne polyester, 500-3000 parts of waterborne polyurethane, 10-200 parts of melamine resin, 10-100 parts of Prussian blue nanoparticles, 10-100 parts of silica nanoparticles, 1-20 parts of wetting agent, and the balance being water.

[0012] Preferably, the preparation method of the Prussian blue composite polyurethane coating liquid includes: sequentially adding a wetting agent diluent, an aqueous polyester diluent, an aqueous polyurethane, a melamine resin diluent, a Prussian blue nanoparticle dispersion, and an aqueous silica dispersion to an alkaline aqueous solution, and then stirring until homogeneous to obtain an aqueous Prussian blue composite polyurethane coating liquid.

[0013] Preferably, the solid content of the Prussian blue composite polyurethane coating liquid is 5-20%.

[0014] Preferably, the preparation method of the Prussian blue composite polyurethane coating liquid includes:

[0015] (1) Take 50-80% water and adjust the pH value to 8.0-9.0; take the wetting agent and add it to the organic solvent to dilute it to obtain the wetting agent dilution solution. Slowly add the wetting agent dilution solution to the above aqueous solution and mix and stir evenly to obtain solution A;

[0016] (2) Take water-based polyester and dilute it with water to obtain water-based polyester diluent. Add the water-based polyester diluent to solution A, stir evenly, and then slowly add water-based polyurethane while stirring continuously to obtain solution B.

[0017] (3) Take melamine resin and dilute it with water to obtain melamine resin dilution. Add the melamine resin dilution to solution B and stir continuously to obtain solution C.

[0018] (4) Take Prussian blue nanoparticles, add them to an organic solvent and ultrasonically disperse them to obtain a Prussian blue nanoparticle dispersion. Slowly add the Prussian blue nanoparticle dispersion to solution C and stir continuously to obtain solution D.

[0019] (5) Take silica nanoparticles and dilute them with water to obtain silica aqueous dispersion. Stir solution D. Under stirring conditions, slowly add silica aqueous dispersion to solution D. After stirring evenly, add the remaining 20~50% water, adjust the pH value to 8.0~9.0, and continue stirring to obtain Prussian blue composite polyurethane coating liquid.

[0020] Further preferred, (1) the mass ratio of wetting agent to organic solvent in the wetting agent dilution is 1:(1~10).

[0021] Further optimization, (2) the mass ratio of waterborne polyester, waterborne polyurethane and water in solution B is 1: (1.5~10): (1~5).

[0022] Further preferred, (3) the mass ratio of melamine resin to water in the melamine resin diluent is 1:(1~10).

[0023] Further optimization, (4) the mass ratio of Prussian blue nanoparticles to organic solvent in the Prussian blue nanoparticle dispersion is 1: (1~10).

[0024] Further preferred, (5) the mass ratio of silica nanoparticles to water in the silica aqueous dispersion is 1: (1~10).

[0025] Further preferred, the mass ratio of wetting agent, waterborne polyester, waterborne polyurethane, melamine resin, Prussian blue nanoparticles and silica nanoparticles is (1~10):(200~600):(800~2000):(60~90):(20~70):(10~50).

[0026] Preferably, the first insulation layer and the second insulation layer are one or both of the following: a silicon dioxide coating and a superhydrophobic TPU / SiO2 sponge layer.

[0027] Preferably, both the first and second insulation layers are superhydrophobic TPU / SiO2 sponge layers.

[0028] Further preferably, the superhydrophobic TPU / SiO2 sponge layer is prepared by spraying a PDMS / SiO2 / ECA dispersion onto the surface of a porous TPU / SiO2 sponge and then drying it.

[0029] Further preferably, the method for preparing the superhydrophobic TPU / SiO2 sponge layer includes:

[0030] (1) Dissolve TPU in an organic solvent, add silica and heat and stir; then add glucose and stir to obtain TPU / SiO2 / glucose dispersion, deposit at room temperature and heat to cure to obtain semi-cured film;

[0031] (2) The semi-cured membrane was placed in deionized water to remove glucose, resulting in a porous TPU / SiO2 sponge;

[0032] (3) Dissolve PDMS in an organic solvent, then add silica and ethyl cyanoacrylate (ECA) and mix to form a PDMS / SiO2 / ECA dispersion;

[0033] (4) Spray the PDMS / SiO2 / ECA dispersion onto the surface of the porous TPU / SiO2 sponge and air dry it naturally to obtain the superhydrophobic TPU / SiO2 (S-TPU / SiO2) sponge.

[0034] As a preferred option, the core layer is a BOPET high-transparency layer.

[0035] A method for preparing a self-heating and heat-insulating window film with photothermal conversion properties includes:

[0036] After applying UV-curing adhesive to both sides of the core layer, the first and second insulation layers are bonded together and cured by UV irradiation. Then, Prussian blue composite polyurethane coating liquid is applied to the surface of the first insulation layer and dried. Finally, the adhesive layer is covered on the surface of the second insulation layer to obtain a self-heating insulation window film with photothermal conversion properties.

[0037] Further optimization involves using ultraviolet light to cure the material at a wavelength of 220-260 nm for a time of 1-20 seconds.

[0038] Further optimization reveals that the coating amount of the Prussian blue composite polyurethane coating solution is 1~30 g / m². 2 .

[0039] Further optimization yields a Prussian blue composite polyurethane coating liquid with a coating weight of 4~10 g / m². 2 .

[0040] Further optimization revealed that the drying temperature of the Prussian blue composite polyurethane coating liquid was 200~290℃, and the drying time was 1~60s.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The self-heating and heat-insulating window film of the present invention with photothermal conversion performance absorbs near-infrared light under sunlight to increase temperature and keep warm. At night, it can reduce the heat transferred outward, greatly reducing the energy consumed for heating in high-latitude regions.

[0043] 2. The self-heating polyurethane coating in the photothermal conversion window film of the present invention includes Prussian blue nanoparticles, which have strong near-infrared absorption capabilities and can raise the temperature to a certain level in a short time under light irradiation. Furthermore, the Prussian blue nanoparticles are dark blue in color and can effectively absorb ultraviolet rays on the film surface, thereby improving the ultraviolet blocking rate.

[0044] 3. The self-heating and heat-insulating window film of the present invention, which has photothermal conversion energy, is convenient to implement, cost-effective, and has excellent energy-saving effect, effectively filling the gap in the current market for window films that do not meet the special needs of high-latitude regions. Attached Figure Description

[0045] Figure 1The graphs show the temperature changes of the self-heating heat-insulating window films with photothermal conversion energy in Examples 1-10 and Comparative Examples 1-2 under sunlight.

[0046] Figure 2 The graphs show the temperature changes of the self-heating heat-insulating window film with photothermal conversion energy in Examples 1-10 and the heat-insulating window films in Comparative Examples 1-2. Detailed Implementation

[0047] The technical solution of the present invention will be further described and illustrated below with reference to specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of helping to understand the present invention and are not intended to limit the scope of the present invention. Furthermore, the accompanying drawings used herein are merely for better illustrating the content disclosed in the present invention and do not have a limiting effect on the scope of protection.

[0048] Unless otherwise specified, the materials used in this invention are commercially available products, and the methods used are conventional technical means.

[0049] In this article, the raw materials include: Prussian blue nanoparticles: Xi'an Qiyue Biotechnology, with average particle sizes of 10, 25, and 50 nm.

[0050] BOPET high transparency layer: Ningbo Changyang Technology, OSG model product.

[0051] Adhesive layer: Tianjin Binlian Technology, BL308 water-based environmentally friendly PVC window adhesive.

[0052] In this study, each 100 parts of Prussian blue composite polyurethane coating liquid contained 0.1 to 10 parts of Prussian blue nanoparticles.

[0053] In this paper, other commercially available products can be used to replace the core layer and adhesive layer to achieve the heating and heat preservation effects described in this invention.

[0054] In this document, the first insulation layer and the second insulation layer can be replaced by other commercially available products with similar performance to the first insulation layer and the second insulation layer of this application.

[0055] In this paper, the test conditions were as follows: at room temperature (25℃), a self-heating insulating window film with photothermal conversion energy was attached to the surface of glass (small enclosed glass room) and continuously exposed to sunlight, with the temperature recorded using an infrared thermometer for 60 minutes; the temperature change is shown in [see attached image]. Figure 1 Block out sunlight and record the temperature using an infrared thermometer for 60 minutes. See [link to thermometer] for temperature changes. Figure 2 . Example 1

[0056] The self-heating insulating window film with photothermal conversion properties in this embodiment includes: a self-heating polyurethane coating, a first insulating layer, a core layer, a second insulating layer, and an adhesive layer; the total thickness is 33.8 μm, and the thickness ratio is 5:40:250:40:3. The first and second insulating layers are both superhydrophobic TPU / SiO2 sponge layers; the core layer is a BOPET high-transparency layer.

[0057] Self-heating polyurethane coating:

[0058] (1) Take 60% water and adjust the pH value to 8.5; take 5 parts of wetting agent and dilute with 10 parts of ethanol, then slowly add the diluted wetting agent solution to the above aqueous solution and mix and stir evenly to obtain solution A;

[0059] (2) Take 400 parts of waterborne polyester and add 800g of deionized water to dilute it to obtain waterborne polyester diluent. Add the waterborne polyester diluent to solution A, stir evenly, and then slowly add 1200 parts of waterborne polyurethane and continue stirring to obtain solution B.

[0060] (3) Take 80 parts of melamine resin and add 160 parts of deionized water to dilute it to obtain melamine resin dilution. Add the melamine resin dilution to solution B and stir continuously to obtain solution C.

[0061] (4) Take 50 parts of Prussian blue nanoparticles with an average particle size of 10 nm (addition amount is 0.5 wt%), add 200 parts of deionized water and ultrasonically disperse to obtain Prussian blue nanoparticle dispersion. Slowly add the Prussian blue nanoparticle dispersion to solution C and stir continuously to obtain solution D.

[0062] (5) Take 30 parts of silica nanoparticles (average particle size of 100 nm) and add 60 parts of deionized water to dilute to obtain silica aqueous dispersion. Stir solution D. Under stirring conditions, slowly add silica aqueous dispersion to solution D. After stirring evenly, add the remaining 40% water, adjust the pH value to 8.5, and continue stirring for 2 hours to obtain waterborne Prussian blue composite polyurethane coating liquid.

[0063] Superhydrophobic TPU / SiO2 sponge layer (S-TPU / SiO2):

[0064] 1) Dissolve 15.2 parts of TPU in 200 parts of DMF, add 2 parts of SiO2 (average particle size of 20nm), and heat and stir at 80℃ for 1h to obtain a TPU / SiO2 dispersion with 7wt% TPU; then add 100 parts of glucose (average particle size of 300μm) and stir evenly to obtain a TPU / SiO2 / glucose dispersion. Pour the TPU / SiO2 / glucose dispersion into a petri dish, allow it to naturally deposit at room temperature for 1h, and then heat and cure at 60℃ for 3h to obtain a semi-cured film.

[0065] (2) The semi-cured film was immersed in deionized water at 40°C to remove glucose, and porous TPU / SiO2 sponge was obtained;

[0066] (3) Dissolve 20 parts of PDMS in 500 parts of ethyl acetate, then add 10 parts of SiO2 and 10 parts of ECA and mix to form a PDMS / SiO2 / ECA dispersion;

[0067] (4) Spray the PDMS / SiO2 / ECA dispersion onto the surface of the porous TPU / SiO2 sponge at a spraying rate of 10 g / m². 2 After air drying, a superhydrophobic TPU / SiO2 (S-TPU / SiO2) sponge is obtained.

[0068] The preparation method of a self-heating and heat-insulating window film with photothermal conversion properties includes: taking OSG finished product, coating both sides with acrylic photocurable adhesive through slit coating, then attaching superhydrophobic TPU / SiO2 (S-TPU / SiO2) sponge, and curing under 235nm ultraviolet light for 5 seconds to obtain a film with first and second heat-insulating layers. Then, the prepared water-based Prussian blue composite polyurethane coating liquid is applied to the surface of the first heat-insulating layer using a D-Bar coating method, wherein the wet coating amount is 8g / m². 2 Then, bake it in an oven at 250℃ for 10 seconds to cure the coating. Finally, apply the adhesive layer to the surface of the second insulation layer through slit coating to obtain a self-heating insulation window film with photothermal conversion properties.

[0069] A self-heating and heat-insulating window film with photothermal conversion properties was applied to the glass surface. The temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Example 2

[0070] Compared with Example 1, the difference is that the self-heating heat-insulating window film with photothermal conversion performance in this example includes: a self-heating polyurethane coating, a first heat-insulating layer, a core layer, a second heat-insulating layer, and an adhesive layer; the first heat-insulating layer and the second heat-insulating layer are both superhydrophobic TPU / SiO2 sponge layers; the total thickness is 34.3μm, and the thickness ratio is 10:40:250:40:3.

[0071] Self-heating polyurethane coating:

[0072] (1) Take 80% water and adjust the pH value to 8.5; take 8 parts of wetting agent and add 20 parts of ethanol to dilute, then slowly add the diluted wetting agent solution to the above aqueous solution and mix and stir evenly to obtain solution A;

[0073] (2) Take 200 parts of waterborne polyester and add 800 parts of deionized water to dilute to obtain waterborne polyester diluent. Add the waterborne polyester diluent to solution A, stir evenly, and then slowly add 1000 parts of waterborne polyurethane and continue stirring to obtain solution B.

[0074] (3) Take 80 parts of melamine resin and add 160 parts of deionized water to dilute it to obtain melamine resin dilution. Add the melamine resin dilution to solution B and stir continuously to obtain solution C.

[0075] (4) Take 50 parts of Prussian blue nanoparticles with an average particle size of 10 nm (addition amount is 0.5 wt%), add 300 parts of deionized water and ultrasonically disperse to obtain Prussian blue nanoparticle dispersion. Slowly add the Prussian blue nanoparticle dispersion to solution C and stir continuously to obtain solution D.

[0076] (5) Take 20 parts of silica nanoparticles (average particle size of 100 nm) and add 60 parts of deionized water to dilute to obtain silica aqueous dispersion. Stir solution D. Under stirring conditions, slowly add silica aqueous dispersion to solution D. After stirring evenly, add the remaining 20% ​​water, adjust the pH value to 8.5, and continue stirring for 5 hours to obtain waterborne Prussian blue composite polyurethane coating liquid.

[0077] A self-heating and heat-insulating window film with photothermal conversion properties was applied to the glass surface. The temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Example 3

[0078] Compared with Example 1, the difference is that the self-heating heat-insulating window film with photothermal conversion performance in this example includes: a self-heating polyurethane coating, a first heat-insulating layer, a core layer, a second heat-insulating layer, and an adhesive layer; the first heat-insulating layer and the second heat-insulating layer are both superhydrophobic TPU / SiO2 sponge layers; the total thickness is 34.8μm, and the thickness ratio is 15:40:250:40:3.

[0079] A self-heating and heat-insulating window film with photothermal conversion properties was applied to the glass surface. The temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Example 4

[0080] Compared with Example 1, the difference is that the amount of Prussian blue nanoparticles added to the Prussian blue composite polyurethane coating liquid is 0.1 wt%.

[0081] A self-heating and heat-insulating window film with photothermal conversion properties was applied to the glass surface. The temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Example 5

[0082] Compared with Example 1, the difference is that the amount of Prussian blue nanoparticles added to the Prussian blue composite polyurethane coating liquid is 0.7wt%.

[0083] A self-heating and heat-insulating window film with photothermal conversion properties was applied to the glass surface. The temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Example 6

[0084] Compared with Example 1, the difference is that the amount of Prussian blue nanoparticles added to the Prussian blue composite polyurethane coating liquid is 0.9 wt%.

[0085] A self-heating and heat-insulating window film with photothermal conversion properties was applied to the glass surface. The temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Example 7

[0086] The difference compared to Example 1 is that the average particle size of the Prussian blue nanoparticles in the Prussian blue composite polyurethane coating liquid is 25 nm.

[0087] A self-heating and heat-insulating window film with photothermal conversion properties was applied to the glass surface. The temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Example 8

[0088] The difference compared to Example 1 is that the average particle size of the Prussian blue nanoparticles in the Prussian blue composite polyurethane coating liquid is 50 nm.

[0089] A self-heating and heat-insulating window film with photothermal conversion properties was applied to the glass surface. The temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Example 9

[0090] Compared with Example 1, the difference is that the first insulation layer and the second insulation layer are silicon dioxide coatings.

[0091] The method for preparing the silica coating includes: taking OSG (Optically Stable Gas) product, depositing silica onto both sides of OSG using the PEVCD method to obtain a film with first and second insulation layers, and then coating the prepared water-based Prussian blue composite polyurethane coating solution onto the surface of the first insulation layer using a D-Bar, wherein the wet coating amount is 8 g / m². 2Then, bake it in an oven at 250℃ for 10 seconds to cure the coating. Finally, apply the adhesive layer to the second insulation layer through a slit coating to obtain a self-heating insulation window film with photothermal conversion properties.

[0092] A self-heating and heat-insulating window film with photothermal conversion properties was applied to the glass surface. The temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Example 10

[0093] Compared with Example 1, the difference is that the self-heating heat-insulating window film with photothermal conversion performance in this example includes: a self-heating polyurethane coating, a core layer, a heat-insulating layer, and an adhesive layer; Prussian blue composite polyurethane coating liquid is directly coated on one side of the core layer surface.

[0094] A self-heating and heat-insulating window film with photothermal conversion properties was applied to the glass surface. The temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Comparative Example 1

[0095] Compared with Example 1, the difference is that the thermal insulation window film in this comparative example does not have a self-heating polyurethane coating.

[0096] The thermal insulation window film in this comparative example includes: a first thermal insulation layer, a core layer, a second thermal insulation layer, and an adhesive layer; both the first and second thermal insulation layers are superhydrophobic TPU / SiO2 sponge layers; the total thickness is 33.3 μm, and the thickness ratio is 40:250:40:3.

[0097] The thermal insulation window film in this comparative example was applied to the glass surface, and the temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 . Comparative Example 2

[0098] Compared with Example 1, the difference is that the self-heating polyurethane coating of the thermal insulation window film in this comparative example does not contain Prussian blue nanoparticles.

[0099] The thermal insulation window film in this comparative example was applied to the glass surface, and the temperature change after exposure to sunlight is shown in the figure. Figure 1 ; see insulation temperature changes Figure 2 .

[0100] according to Figure 1 , Figure 2It is known that by changing the amount and particle size of Prussian blue nanoparticles added to the self-heating polyurethane coating, the number of layers and composition of the insulation layer are adjusted, thus achieving better heating and insulation effects. However, without adding Prussian blue nanoparticles or abandoning the self-heating polyurethane coating, the heating and insulation performance are significantly reduced.

[0101] In summary, the self-heating and heat-insulating window film of the present invention with photothermal conversion properties absorbs near-infrared light under sunlight to raise the temperature and keep it warm. At night, it can reduce the heat transferred outward, greatly reducing the energy consumed for heating in high-latitude regions.

[0102] All aspects, embodiments, and features of this invention should be considered illustrative in all respects and not limiting of the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0103] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.

[0104] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A self-heating and heat-insulating window film with photothermal conversion properties, characterized in that, It comprises, in sequence: a self-heating polyurethane coating, a first insulation layer, a core layer, a second insulation layer, and an adhesive layer; the thickness ratio of the self-heating polyurethane coating, the first insulation layer, the core layer, and the second insulation layer is (1~10):(20~50):(200~500):(20~50). The self-heating polyurethane coating is prepared from a Prussian blue composite polyurethane coating liquid. The raw materials of the Prussian blue composite polyurethane coating liquid include: 100-1000 parts of waterborne polyester, 500-3000 parts of waterborne polyurethane, 10-200 parts of melamine resin, 10-100 parts of Prussian blue nanoparticles, 10-100 parts of silica nanoparticles, 1-20 parts of wetting agent, and the balance being water. The amount of Prussian blue nanoparticles added to the Prussian blue composite polyurethane coating solution is 0.1~10wt%; the average particle size of the Prussian blue nanoparticles is 10~50nm. Both the first and second insulation layers are superhydrophobic TPU / SiO2 sponge layers; their preparation method includes the following steps: (1) Dissolve TPU in an organic solvent, add silica and heat and stir; then add glucose and stir to obtain TPU / SiO2 / glucose dispersion, deposit at room temperature and heat to cure to obtain semi-cured film; (2) The semi-cured membrane was placed in deionized water to remove glucose, resulting in a porous TPU / SiO2 sponge; (3) Dissolve PDMS in an organic solvent, then add silica and ethyl cyanoacrylate (ECA) and mix to form a PDMS / SiO2 / ECA dispersion; (4) Spray the PDMS / SiO2 / ECA dispersion onto the surface of the porous TPU / SiO2 sponge and air dry it naturally to obtain the superhydrophobic TPU / SiO2 sponge.

2. The self-heating and heat-insulating window film with photothermal conversion properties according to claim 1, characterized in that, The amount of Prussian blue nanoparticles added to the Prussian blue composite polyurethane coating solution is 0.1~5wt%.

3. The self-heating and heat-insulating window film with photothermal conversion properties according to claim 1, characterized in that, The amount of Prussian blue nanoparticles added to the Prussian blue composite polyurethane coating solution is 0.1~0.9wt%.

4. The self-heating and heat-insulating window film with photothermal conversion properties according to claim 1, characterized in that, The mass ratio of the wetting agent, waterborne polyester, waterborne polyurethane, melamine resin, Prussian blue nanoparticles, and silica nanoparticles is (1~10):(200~600):(800~2000):(60~90):(20~70):(10~50).

5. The self-heating and heat-insulating window film with photothermal conversion properties according to claim 1, characterized in that, The preparation method of the Prussian blue composite polyurethane coating liquid includes: adding a wetting agent diluent, an aqueous polyester diluent, an aqueous polyurethane, a melamine resin diluent, a Prussian blue nanoparticle dispersion, and an aqueous silica dispersion to an alkaline aqueous solution in sequence, and then stirring evenly to obtain an aqueous Prussian blue composite polyurethane coating liquid.

6. The self-heating and heat-insulating window film with photothermal conversion properties according to claim 1, characterized in that, The core layer is a BOPET high-transparency layer.

7. The self-heating and heat-insulating window film with photothermal conversion properties according to claim 1, characterized in that, The preparation method of the Prussian blue composite polyurethane coating liquid includes the following steps: (1) Take 50-80% water and adjust the pH value to 8.0-9.0; take the wetting agent and add it to the organic solvent to dilute it to obtain the wetting agent dilution solution. Slowly add the wetting agent dilution solution to the above aqueous solution and mix and stir evenly to obtain solution A; (2) Take water-based polyester and dilute it with water to obtain water-based polyester diluent. Add the water-based polyester diluent to solution A, stir evenly, and then slowly add water-based polyurethane while stirring continuously to obtain solution B. (3) Take melamine resin and dilute it with water to obtain melamine resin dilution. Add the melamine resin dilution to solution B and stir continuously to obtain solution C. (4) Prussian blue nanoparticles were added to an organic solvent and ultrasonically dispersed to obtain a Prussian blue nanoparticle dispersion. The Prussian blue nanoparticle dispersion was slowly added to solution C and stirred continuously to obtain solution D. (5) Take silica nanoparticles and dilute them with water to obtain silica aqueous dispersion. Stir solution D. Under stirring conditions, slowly add silica aqueous dispersion to solution D. After stirring evenly, add the remaining 20~50% water, adjust the pH value to 8.0~9.0, and continue stirring to obtain Prussian blue composite polyurethane coating liquid.

8. The self-heating and heat-insulating window film with photothermal conversion properties according to claim 1, characterized in that, The preparation method of the Prussian blue composite polyurethane coating liquid includes the following steps: (1) Take 60% water and adjust the pH value to 8.5; take 5 parts of wetting agent and dilute with 10 parts of ethanol, then slowly add the diluted wetting agent solution to the above aqueous solution and mix and stir evenly to obtain solution A; (2) Take 400 parts of waterborne polyester and add 800g of deionized water to dilute it to obtain waterborne polyester diluent. Add the waterborne polyester diluent to solution A, stir evenly, and then slowly add 1200 parts of waterborne polyurethane and continue stirring to obtain solution B. (3) Take 80 parts of melamine resin and add 160 parts of deionized water to dilute it to obtain melamine resin dilution. Add the melamine resin dilution to solution B and stir continuously to obtain solution C. (4) Take 50 parts of Prussian blue nanoparticles with an average particle size of 10 nm, add 200 parts of deionized water and ultrasonically disperse to obtain Prussian blue nanoparticle dispersion. Slowly add the Prussian blue nanoparticle dispersion to solution C and stir continuously to obtain solution D. (5) Take 30 parts of silica nanoparticles and add 60 parts of deionized water to dilute to obtain silica aqueous dispersion. Stir solution D. Under stirring conditions, slowly add silica aqueous dispersion to solution D. After stirring evenly, add the remaining 40% water, adjust the pH value to 8.5, and continue stirring for 2 hours to obtain waterborne Prussian blue composite polyurethane coating liquid.

9. A method for preparing a self-heating heat-insulating window film with photothermal conversion properties as described in claim 1, characterized in that, The preparation method includes: After applying UV-curing adhesive to both sides of the core layer, the first and second insulation layers are bonded together and cured by UV irradiation. Then, Prussian blue composite polyurethane coating liquid is applied to the surface of the first insulation layer and dried. Finally, the adhesive layer is covered on the surface of the second insulation layer to obtain a self-heating insulation window film with photothermal conversion properties.

10. The method for preparing the self-heating heat-insulating window film with photothermal conversion properties according to claim 9, characterized in that, The coating amount of the Prussian blue composite polyurethane coating solution is 1~30 g / m³. 2 .

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