Sun-shading film with multi-layer structure and preparation method of sun-shading film

Abstract

The invention provides a sunshade film with a multi-layer structure and a preparation method thereof, and the sunshade film sequentially comprises an isolation layer, a bonding layer, a multi-layer reflecting film, a composite functional layer and a protective layer from front to back; the composite functional layer at least comprises one of a heat insulation layer, an ultraviolet-proof layer, an enhancement layer, an anti-fog layer and an anti-reflection layer, and the bonding layer is transparent. By means of the structural design, infrared rays and ultraviolet rays in sunlight can be effectively blocked, heat accumulation in a vehicle is reduced, and meanwhile interior trim, a driver and passengers are protected against ultraviolet rays. And the external reflection of the multiple layers of reflecting films can make the outside of the glass present gorgeous colors. The composite function layer reduces reflection and interference effects of light rays in the multi-layer reflecting film on the interior of a vehicle, and avoids internal reflection of color change generated by the multi-layer reflecting film in the vehicle under light irradiation, so that visual interference of a driver is reduced, visual fatigue and vertigo are reduced, driving safety is improved, and driving safety is improved. Differentiation and adjustment of spectrums reflected outwards and inwards by the sunshade film are achieved.

Description

Technical Field

[0001] The invention relates to the field of automobile sunshade films, and in particular to a sunshade film with a multi-layer structure and a preparation method thereof. Background Art

[0002] Traditional sunshade films are widely used in the automotive industry, mainly to reduce the temperature rise and UV exposure caused by solar radiation in the car. These films usually provide basic heat insulation and UV protection, but there are some obvious defects. First, while many traditional sunshade films provide heat insulation and UV protection, they will significantly reduce the light transmittance of the window and affect the driver's vision clarity, which is particularly dangerous in low-light environments. Secondly, these films have poor durability and are prone to peeling or fading after long-term use, requiring frequent replacement, which increases maintenance costs.

[0003] In order to improve these problems, multilayer reflective film technology, also known as rainbow film, has been developed to achieve specific reflection and transmission effects through the interference effect of light. It is made up of multiple layers of materials with different refractive indices stacked alternately. After precisely controlling the thickness and number of layers, it can enhance the reflection or selective reflection of light of specific wavelengths, thereby enhancing the heat insulation effect. However, while this multilayer reflective film solves some traditional problems, it also introduces new challenges. In particular, under certain lighting conditions, this film may produce a rainbow visual effect. These color changes will increase the appearance of the car. But for the driver in the car, it may cause interference to the driver, causing visual fatigue or even dizziness, especially when the light changes drastically or when driving at high speeds.

[0004] One attempt in the prior art is to add light absorbing materials to the pressure sensitive adhesive of the multi-layer reflective film sunshade film to further improve the sunshade effect, such as Figure 6 As shown in the figure, the pressure-sensitive adhesive is located between the glass and the multi-layer reflective film. Although this method can reduce the amount of light passing through the film to a certain extent and reduce the internal temperature, it also leads to a reduction in the rainbow effect. This is because although the light-absorbing material can absorb part of the light, it also affects the light reflection characteristics of the multi-layer reflective film to the outside, reducing the amplitude of color changes, which may reduce the overall beauty and functionality of the sunshade film. In addition, it does not significantly reduce visual fatigue and glare for the driver in the car.

[0005] In summary, although the multilayer reflective film is a technical improvement over the traditional sunshade film, there are still many areas that need to be optimized in practical applications. The present invention aims to solve the problem of visual interference caused by the existing multilayer reflective film to the occupants of the vehicle while providing effective sunshade, and to achieve a more efficient, safe and beautiful sunshade film by improving the material combination and structural design. Summary of the invention

[0006] In view of the above analysis, the present invention aims to provide a sunshade film with a multi-layer structure and a preparation method thereof to solve the problems in the background technology.

[0007] The purpose of the present invention is mainly achieved through the following technical solutions:

[0008] On the one hand, the present invention provides a sunshade film with a multi-layer structure, which includes, from front to back, an isolation layer, an adhesive layer, a multi-layer reflective film, a composite functional layer and a protective layer; the composite functional layer includes at least one of a heat insulation layer, an ultraviolet protection layer, a reinforcement layer, an anti-fog layer and an anti-reflection layer, and the adhesive layer is transparent.

[0009] In one or more embodiments, the isolation layer is one of a PE release film, a PET release film, a silicone release film and a polyvinyl alcohol film.

[0010] In one or more embodiments, the adhesive layer is a pressure-sensitive adhesive.

[0011] In one or more embodiments, the adhesive layer contains a transparent UV absorbing barrier material.

[0012] In one or more embodiments, the thermal insulation layer is made of one of metal oxides and nano-ceramic materials.

[0013] In one or more embodiments, the protective layer is one of epoxy resin, polyurethane and PE protective film.

[0014] In one or more embodiments, the anti-reflection layer is formed by coating the heat insulation layer and / or the UV protection layer with nanoparticle material.

[0015] In one or more embodiments, the thickness of the reinforcement layer is ≥50 μm; and the thickness of the bonding layer is 5-10 μm.

[0016] In one or more embodiments, the reinforcement layer is a PET film.

[0017] In a second aspect, the present invention provides a method for preparing a sunshade film having a multilayer structure, comprising the following steps:

[0018] S1: Select a multilayer reflective film as a substrate and coat one side with a composite functional layer;

[0019] S2: providing a protective layer on the composite functional layer;

[0020] S3: coating an adhesive layer on the other side of the multilayer reflective film;

[0021] S4: Covering the adhesive layer with an isolation layer.

[0022] The technical solution of the present invention has at least the following beneficial effects:

[0023] (1) Multifunctional hierarchical structure to improve sunshade and heat insulation effect: The present invention uses a multi-layer composite structure to sequentially arrange a heat insulation layer, an ultraviolet protection layer and a reinforcement layer in the film body. This structural design can effectively block infrared and ultraviolet rays in sunlight, reduce heat accumulation in the car, improve the comfort level in the car, and protect the interior and the driver and passengers from ultraviolet damage.

[0024] (2) Anti-reflection and interference functions to reduce visual interference: The heat-insulating layer and anti-reflection layer in the composite functional layer of the present invention reduce the reflection and interference effect of the multi-layer reflective film into the vehicle, and avoid the color change of the rainbow film under light irradiation, thereby reducing the driver's visual interference, reducing visual fatigue and dizziness, and improving driving safety.

[0025] (3) Anti-fog function, maintaining clear vision: The anti-fog layer design of the film can maintain the clarity of the car windows in high humidity environments and avoid blurred vision caused by fog accumulation. It is particularly suitable for cold or humid environments, improving driving safety and vision.

[0026] (4) High durability and extended service life: The reinforcement layer and protective layer in the membrane structure make the present invention have high scratch resistance and wear resistance. Even if exposed to harsh conditions such as high temperature and ultraviolet rays for a long time, the membrane can maintain a good condition, extend the service life, and reduce maintenance and replacement costs.

[0027] (5) Beautiful appearance, practicality and visual effects: The design of the present invention ensures that the multi-layer film body maintains light transmittance and beautiful appearance while providing high efficiency in heat insulation and sun shading. Even with the addition of multiple functional layers, the film body still has good transparency, ensuring the visual effects and beautiful appearance inside and outside the car.

[0028] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be achieved and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0030] Figure 1 It is a schematic structural diagram of a sunshade film with a multi-layer structure according to the present invention.

[0031] Figure 2This is a schematic diagram of the multilayer structure of the composite functional layer of Example 1 of the present invention.

[0032] Figure 3 This is a schematic diagram of the multilayer structure of the composite functional layer of Example 2 of the present invention.

[0033] Figure 4 Schematic diagram of the multilayer structure of the composite functional layer of Examples 3 and 5 of the present invention.

[0034] Figure 5 Schematic diagram of the multilayer structure of the composite functional layer of Example 4 of the present invention.

[0035] Figure 6 It is a schematic diagram of the structure of the sunshade film in the prior art.

[0036] Figure 7 It is a reflection spectrum diagram of the vehicle interior in the range of 700nm to 780nm, in which A is the prior art and B is embodiment 4 of the present invention.

[0037] Figure 8 It is a reflection spectrum diagram of the vehicle interior in the range of 550nm to 750nm, in which E is the prior art and F is embodiment 4 of the present invention.

[0038] Fig. 9 It is a car exterior reflection spectrum diagram in the range of 700nm to 780nm, in which C is the prior art and D is Example 4 of the present invention.

[0039] Fig.10 It is a spectrum diagram of the vehicle exterior reflection in the range of 550nm to 750nm, in which G is the prior art and H is Example 4 of the present invention.

[0040] Fig.11 is an absorption spectrum diagram, in which J is the prior art and K is Example 4 of the present invention.

[0041] Fig.12 This is an electron scanning microscope image of the cross section of the sunshade film of Example 6 of the present invention, wherein area A is a multi-layer reflective film structure, and the right image is a partial enlarged image.

[0042] Figure numerals: 1. Isolation layer; 2. Adhesive layer; 3. Multilayer reflective film; 4. Composite functional layer; 401. Heat insulation layer; 402. Anti-ultraviolet layer; 403. Reinforcement layer; 404. Anti-fog layer; 405. Anti-reflection layer; 5. Protective layer. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principle of the present invention, but are not used to limit the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0044] Terminology explanation: The front in this embodiment refers to the side close to the window glass, and the rear refers to the side away from the window glass. From front to back, that is, from the side close to the glass to the side away from the glass.

[0045] Figure 6 The structure shown in is the structure of a car glass film with a multi-layer reflective film in the prior art. There is only a pressure-sensitive adhesive or a pressure-sensitive adhesive mixed with a certain light-absorbing or heat-insulating material between the multi-layer reflective film and the glass, that is, the composite functional layer is located at the pressure-sensitive adhesive, that is, the composite functional layer is located in front of the multi-layer reflective film, which is different from the composite functional layer of the present invention, which is located behind the multi-layer reflective film. Such a multi-functional layer can reduce the reflected light from the multi-layer film to the interior of the car and reduce the "rainbow" effect in the sight line inside the car. The prior art described in this article, namely Figure 6 Multilayer reflective film structure.

[0046] The present invention provides a sunshade film with a multi-layer structure, which comprises, from front to back, an isolation layer 1, an adhesive layer 2, a multi-layer reflective film 3, a composite functional layer 4 and a protective layer 5; the composite functional layer 4 comprises at least one of a heat insulation layer 401, an ultraviolet protection layer 402, a reinforcement layer 403, an anti-fog layer 404 and an anti-reflection layer 405, and the adhesive layer 2 is transparent.

[0047] In the embodiment listed below, the thickness of the isolation layer is 25μm, the adhesive layer is 10μm, the multilayer reflective film is 40μm, the heat insulation layer is 1μm, the UV protection layer is 100nm, the reinforcement layer is 100μm, and the anti-fog layer is 8μm. In other embodiments, those skilled in the art can also choose the thickness according to actual needs to achieve the technical effect of the present invention, which is not limited here.

[0048] Example 1

[0049] See also Figure 2 A sunshade film with a multi-layer structure comprises, from front to back, an isolation layer 1, an adhesive layer 2, a multi-layer reflective film 3, a composite functional layer 4 and a protective layer 5; the composite functional layer 4 is a heat insulation layer 401 and an anti-ultraviolet layer 402, and the adhesive layer 2 is transparent.

[0050] The preparation method is as follows:

[0051] Select the multilayer reflective film 3 as the substrate. Coat the substrate with a heat-insulating layer 401. In this embodiment, indium tin oxide is used to give the film basic heat-insulating properties. After coating, a drying process is performed using a drying device to volatilize the solvent in the heat-insulating layer 401 and ensure that the coating is stably adhered.

[0052] After the heat insulation layer 401 is completely dried, an anti-ultraviolet layer 402 is coated thereon to block ultraviolet rays. In this embodiment, zinc oxide is used, which is a widely used inorganic ultraviolet blocking material, not only because it can effectively absorb UVA and UVB rays, but also because it can maintain a high degree of transparency in the coating. The nanoparticle form of zinc oxide can be evenly coated on the heat insulation layer 401 to form a transparent anti-ultraviolet protective layer, which does not affect the visual effect while providing strong UV protection. After coating, it is dried again to ensure the uniformity and adhesion of the layer.

[0053] After the anti-ultraviolet layer 402 is dried, the protective layer 5 is coated, which can enhance the scratch resistance and durability of the film. In this embodiment, the protective layer 5 is a polyurethane film. After coating, it is dried at 80° C. for 3 minutes to ensure the smoothness and adhesion of the surface.

[0054] After the protective layer 5 is coated, the adhesive layer 2 is coated on the back of the multilayer reflective film 3. In this embodiment, a pressure-sensitive adhesive is used as the adhesive layer 2, in which oxybenzone is added as a UV absorption barrier material, which can effectively absorb UVA and UVB light and is added to the transparent pressure-sensitive adhesive to provide UV protection without affecting transparency.

[0055] The surface of the pressure-sensitive adhesive layer is covered with an isolation layer 1, which is a PET film in this embodiment, for easy winding and cutting. This isolation layer 1 can protect the pressure-sensitive adhesive from contamination before packaging, transportation and installation, and prevent the pressure-sensitive adhesive from losing its viscosity.

[0056] Example 2

[0057] See also Figure 3 A sunshade film with a multi-layer structure includes, from front to back, an isolation layer 1, an adhesive layer 2, a multi-layer reflective film 3, a composite functional layer 4 and a protective layer 5; the composite functional layer 4 is a heat insulation layer 401, an anti-ultraviolet layer 402 and a reinforcement layer 403, and the adhesive layer 2 is transparent.

[0058] The preparation method is as follows:

[0059] Select the multilayer reflective film 3 as the substrate. Coat the substrate with a heat-insulating layer 401. In this embodiment, indium tin oxide is used to give the film basic heat-insulating properties. After coating, a drying process is performed using a drying device to volatilize the solvent in the heat-insulating layer 401 and ensure that the coating is stably adhered.

[0060] After the heat insulation layer 401 is completely dried, an anti-ultraviolet layer 402 is coated thereon to block ultraviolet rays. In this embodiment, zinc oxide is used, which is a widely used inorganic ultraviolet blocking material, not only because it can effectively absorb UVA and UVB rays, but also because it can maintain a high degree of transparency in the coating. The nanoparticle form of zinc oxide can be evenly coated on the heat insulation layer 401 to form a transparent anti-ultraviolet protective layer, which does not affect the visual effect while providing strong UV protection. After coating, it is dried again to ensure the uniformity and adhesion of the coating.

[0061] After the UV protection layer 402 is dried, a layer of pressure-sensitive adhesive is evenly coated on the UV protection layer 402. The main function of this layer of pressure-sensitive adhesive is to firmly attach the reinforcing layer 403 to be added to the UV protection layer 402. The coating thickness of the pressure-sensitive adhesive is controlled to be 15 μm to ensure the adhesion effect without affecting the light transmittance.

[0062] In the present embodiment, a transparent PET substrate is selected as the reinforcing layer 403, and the PET substrate is superimposed on the pressure-sensitive adhesive layer to ensure that there are no bubbles and wrinkles, and the fit is firm. During the lamination process, a rolling device can be used to slightly pressurize to ensure the tightness between the PET substrate and the anti-ultraviolet layer 402. The PET substrate can protect the sensitive layers in the film, such as the anti-ultraviolet layer 402 and the heat-insulating layer 401, from the direct influence of external environmental factors such as humidity and chemicals, thereby extending the service life of the film. At the same time, the PET substrate provides a solid supporting structure to help maintain the structural integrity and stability of the entire film. In a multilayer film, each layer may be very thin and easy to deform or damage, and the addition of the PET substrate can increase the overall thickness and toughness of the film, making it more durable.

[0063] A protective layer 5 is coated on the PET substrate, which can enhance the scratch resistance and durability of the film. In this embodiment, the protective layer 5 is made of epoxy resin; after coating, it is dried at 80° C. for 3 minutes to ensure its surface smoothness and adhesion effect.

[0064] After the protective layer 5 is coated, the adhesive layer 2 is coated on the back of the multilayer reflective film 3. In this embodiment, a pressure-sensitive adhesive is used as the adhesive layer 2, in which oxybenzone is added as a UV absorption barrier material, which can effectively absorb UVA and UVB light and is added to the transparent pressure-sensitive adhesive to provide UV protection without affecting transparency.

[0065] The surface of the pressure-sensitive adhesive layer is covered with an isolation layer 1, which is a PET film in this embodiment, for easy winding and cutting. This isolation layer 1 can protect the pressure-sensitive adhesive from contamination before packaging, transportation and installation, and prevent the pressure-sensitive adhesive from losing its viscosity.

[0066] Example 3

[0067] See also Figure 4 A sunshade film with a multi-layer structure includes, from front to back, an isolation layer 1, an adhesive layer 2, a multi-layer reflective film 3, a composite functional layer 4 and a protective layer 5; the composite functional layer 4 is a heat insulation layer 401, an anti-ultraviolet layer 402, a reinforcement layer 403, and an anti-fog layer 404, and the adhesive layer 2 is transparent.

[0068] The preparation method is as follows:

[0069] Select the multilayer reflective film 3 as the substrate. Coat the substrate with a heat-insulating layer 401. In this embodiment, indium tin oxide is used to give the film basic heat-insulating properties. After coating, a drying process is performed using a drying device to volatilize the solvent in the heat-insulating layer 401 and ensure that the coating is stably adhered.

[0070] After the heat insulation layer 401 is completely dried, an anti-ultraviolet layer 402 is coated thereon to block ultraviolet rays. In this embodiment, zinc oxide is used, which is a widely used inorganic ultraviolet blocking material, not only because it can effectively absorb UVA and UVB rays, but also because it can maintain a high degree of transparency in the coating. The nanoparticle form of zinc oxide can be evenly coated on the heat insulation layer 401 to form a transparent anti-ultraviolet protective layer, which does not affect the visual effect while providing strong UV protection. After coating, it is dried again to ensure the uniformity and adhesion of the layer.

[0071] After the UV protection layer 402 is dried, a layer of pressure-sensitive adhesive is evenly coated on the UV protection layer 402. The main function of this layer of pressure-sensitive adhesive is to firmly attach the reinforcing layer 403 to be added to the UV protection layer 402. The coating thickness of the pressure-sensitive adhesive is controlled to be 15 μm to ensure the adhesion effect without affecting the light transmittance.

[0072] In the present embodiment, a transparent PET substrate is selected as the reinforcing layer 403, and the PET substrate is superimposed on the pressure-sensitive adhesive layer to ensure that there are no bubbles and wrinkles, and the fit is firm. During the lamination process, a rolling device can be used to slightly pressurize to ensure the fit between the PET substrate and the UV protection layer 402. The PET substrate can protect the sensitive layers in the film, such as the UV absorbing layer and the heat insulating layer 401, from being directly affected by external environmental factors such as humidity and chemicals, thereby extending the service life of the film. At the same time, the PET substrate provides a solid supporting structure to help maintain the structural integrity and stability of the entire film. In a multilayer film, each layer may be very thin and easy to deform or damage, and the addition of the PET substrate can increase the overall thickness and toughness of the film, making it more durable.

[0073] An anti-fog layer 404 is coated on the PET substrate. The anti-fog layer 404 can effectively prevent fogging caused by moisture and maintain the clarity of the film. In this embodiment, the anti-fog material is a nano-silicon dioxide coating. Nano-SiO2 particles are used to increase the hydrophilicity of the film surface, so that water vapor forms a uniform water film on the surface instead of droplets. After coating, the anti-fog coating is dried by infrared drying equipment to ensure stable adhesion of the material.

[0074] The protective layer 5 is covered on the anti-fog layer 404 to prevent the anti-fog adhesive from being contaminated and damaged before packaging, transportation and installation. In this embodiment, the protective layer 5 is an electrostatic film, and in this embodiment, a PE film is used. In other embodiments, a PVC film or a PPS film can also be used.

[0075] After the protective layer 5 is covered, the adhesive layer 2 is coated on the back of the multilayer reflective film 3. In this embodiment, a pressure-sensitive adhesive is used as the adhesive layer 2, in which oxybenzone is added as a UV absorption barrier material, which can effectively absorb UVA and UVB light and is added to the transparent pressure-sensitive adhesive to provide UV protection without affecting transparency.

[0076] The surface of the pressure-sensitive adhesive layer is covered with an isolation layer 1, which is a PET film in this embodiment, for easy winding and cutting. This isolation layer 1 can protect the pressure-sensitive adhesive from contamination before packaging, transportation and installation, and prevent the pressure-sensitive adhesive from losing its viscosity.

[0077] Example 4

[0078] See also Figure 5 A sunshade film with a multi-layer structure includes, from front to back, an isolation layer 1, an adhesive layer 2, a multi-layer reflective film 3, a composite functional layer 4 and a protective layer 5; the composite functional layer 4 is a heat insulation layer 401, an ultraviolet protection layer 402, an anti-reflection layer 405 and a reinforcement layer 403, and the adhesive layer 2 is transparent.

[0079] Multilayer reflective film 3 was selected as the substrate. Metal oxide indium tin oxide (90% indium oxide and 10% tin oxide) was deposited on the substrate using magnetron sputtering technology, with the power set to 2 kW. The working pressure was set to 2.5 mTorr. Lower pressure helps to reduce gas scattering, improve deposition rate and film uniformity, and argon is used as the sputtering gas with a deposition rate of The indium tin oxide film is annealed to improve the transparency of the film. Indium tin oxide has good infrared reflection ability and can significantly improve the thermal insulation effect.

[0080] A heat insulation layer 401 and an anti-ultraviolet layer 402 are coated on the magnetron sputtering coating. In this embodiment, nano-aluminum oxide is used as the heat insulation layer 401, and zinc oxide is used as the anti-ultraviolet layer 402. After coating, a drying process is performed using infrared drying equipment to volatilize the solvent in the heat insulation layer 401 and the anti-ultraviolet layer 402 coatings and ensure stable adhesion of the coatings.

[0081] A structure with low reflectivity is created on the heat-insulating UV-proof layer 402 to reduce light reflection and improve light transmittance. Nano-zirconium oxide (ZrO2) is used to prepare a nano-coating liquid and a small amount of binder is added to improve the adhesion of the coating. The anti-reflection layer 405 is evenly coated on the surface of the heat-insulating UV-proof layer 402 to ensure uniform coverage of the coating. After drying, heating and curing, the nanoparticles are tightly attached to form a stable anti-reflection layer 405.

[0082] After the anti-reflection layer 405 is dried, a layer of pressure-sensitive adhesive is evenly coated on the anti-reflection layer 405. The main function of this layer of pressure-sensitive adhesive is to firmly attach the reinforcing layer 403 to be added to the anti-reflection layer 405. The coating thickness of the pressure-sensitive adhesive is controlled to be 15 μm to ensure the adhesion effect without affecting the light transmittance.

[0083] In the present embodiment, a transparent PET substrate is selected as the reinforcing layer 403, and the PET substrate is superimposed on the pressure-sensitive adhesive layer to ensure that there are no bubbles and wrinkles, and the fit is firm. During the lamination process, a rolling device can be used to slightly pressurize to ensure the fit between the PET substrate and the UV protection layer 402. The PET substrate can protect the sensitive layers in the film, such as the UV absorbing layer and the heat insulating layer 401, from being directly affected by external environmental factors such as humidity and chemicals, thereby extending the service life of the film. At the same time, the PET substrate provides a solid supporting structure to help maintain the structural integrity and stability of the entire film. In a multilayer film, each layer may be very thin and easy to deform or damage, and the addition of the PET substrate can increase the overall thickness and toughness of the film, making it more durable.

[0084] A protective layer 5 is coated on the PET substrate, which can enhance the scratch resistance and durability of the film. In this embodiment, the protective layer 5 is an epoxy resin film. Epoxy resin is widely used in protective films due to its excellent physical strength and transparency, as well as excellent chemical resistance and wear resistance. Epoxy resin provides a hard surface layer that can effectively resist scratches and wear while maintaining the original visual transparency and aesthetics. After coating, it is dried at 80°C for 3 minutes to ensure its surface smoothness and adhesion effect.

[0085] After the protective layer 5 is coated, the adhesive layer 2 is coated on the back of the multilayer reflective film 3. In this embodiment, a pressure-sensitive adhesive is used as the adhesive layer 2, in which oxybenzone is added as a UV absorption barrier material, which can effectively absorb UVA and UVB light and is added to the transparent pressure-sensitive adhesive to provide UV protection without affecting transparency.

[0086] The surface of the pressure-sensitive adhesive layer is covered with an isolation layer 1, which is a PET film in this embodiment, for easy winding and cutting. This isolation layer 1 can protect the pressure-sensitive adhesive from contamination before packaging, transportation and installation, and prevent the pressure-sensitive adhesive from losing its viscosity.

[0087] Example 5

[0088] See also Figure 3 A sunshade film with a multi-layer structure includes, from front to back, an isolation layer 1, an adhesive layer 2, a multi-layer reflective film 3, a composite functional layer 4 and a protective layer 5; the composite functional layer 4 is a heat insulation layer 401, an ultraviolet protection layer 402 and a reinforcement layer 403, and the adhesive layer 2 is transparent. The difference from Example 2 is that the dyed primary color PET film in the prior art is used to replace the transparent PET substrate.

[0089] The preparation method is as follows:

[0090] Select the multilayer reflective film 3 as the substrate. Coat the substrate with a heat-insulating layer 401. In this embodiment, indium tin oxide is used to give the film basic heat-insulating properties. After coating, a drying process is performed using a drying device to volatilize the solvent in the heat-insulating layer 401 and ensure that the coating is stably adhered.

[0091] After the heat insulation layer 401 is completely dried, an anti-ultraviolet layer 402 is coated thereon to block ultraviolet rays. In this embodiment, zinc oxide is used, which is a widely used inorganic ultraviolet blocking material, not only because it can effectively absorb UVA and UVB rays, but also because it can maintain a high degree of transparency in the coating. The nanoparticle form of zinc oxide can be evenly coated on the heat insulation layer 401 to form a transparent anti-ultraviolet protective layer, which does not affect the visual effect while providing strong UV protection. After coating, it is dried again to ensure the uniformity and adhesion of the coating.

[0092] After the UV protection layer 402 is dried, a layer of pressure-sensitive adhesive is evenly coated on the UV protection layer 402. The main function of this layer of pressure-sensitive adhesive is to firmly attach the reinforcing layer 403 to be added to the UV protection layer 402. The coating thickness of the pressure-sensitive adhesive is controlled to be 15 μm to ensure the adhesion effect without affecting the light transmittance.

[0093] In this embodiment, the original color film PET substrate after dyeing in the prior art is selected as the reinforcing layer 403, and the PET substrate after dyeing is superimposed on the pressure-sensitive adhesive layer to ensure that there are no bubbles and wrinkles, and the fit is firm. In the lamination process, a rolling device can be used to slightly pressurize to ensure the closeness between the original color film PET substrate after dyeing and the anti-ultraviolet layer 402. The original color film PET substrate after dyeing can protect the sensitive layers in the film, such as the UV absorbing layer and the heat insulating layer 401, from the direct influence of external environmental factors such as humidity and chemicals, thereby extending the service life of the film. At the same time, the original color film PET substrate after dyeing provides a solid supporting structure to help maintain the structural integrity and stability of the entire film. In a multilayer film, each layer may be very thin and easy to deform or damage. The addition of the original color film PET substrate can increase the overall thickness and toughness of the film, making it more durable.

[0094] A protective layer 5 is coated on the dyed primary color film PET substrate, which can enhance the scratch resistance and durability of the film. In this embodiment, the protective layer 5 is an epoxy resin film. Epoxy resin is widely used in protective films due to its excellent physical strength and transparency, as well as excellent chemical resistance and wear resistance. Epoxy resin provides a hard surface layer that can effectively resist scratches and wear while maintaining the original visual transparency and aesthetics. After coating, it is dried at 80°C for 3 minutes to ensure its surface smoothness and adhesion effect.

[0095] After the protective layer 5 is coated, the adhesive layer 2 is coated on the back of the multilayer reflective film 3. In this embodiment, a pressure-sensitive adhesive is used as the adhesive layer 2, in which oxybenzone is added as a UV absorption barrier material, which can effectively absorb UVA and UVB light and is added to the transparent pressure-sensitive adhesive to provide UV protection without affecting transparency.

[0096] The surface of the pressure-sensitive adhesive layer is covered with an isolation layer 1, which is a PET film in this embodiment, for easy winding and cutting. This isolation layer 1 can protect the pressure-sensitive adhesive from contamination before packaging, transportation and installation, and prevent the pressure-sensitive adhesive from losing its viscosity.

[0097] Example 6

[0098] Fig.12 The electron microscope scanning image of the present invention is shown, wherein the A region is a multilayer reflective film structure, and the right image is a local enlarged image of the multilayer reflective film.

[0099] A sunshade film with a multi-layer structure includes, from front to back, an isolation layer 1, an adhesive layer 2, a multi-layer reflective film 3, a composite functional layer 4 and a protective layer 5; the composite functional layer 4 is a heat insulation layer 401, an anti-ultraviolet layer 402 and a reinforcement layer 403, and the adhesive layer 2 is transparent. This embodiment introduces a multi-layer superimposed PET film, a total of three layers, to enhance the explosion-proof function of the sunshade film.

[0100] Select the multilayer reflective film 3 as the substrate. Evenly coat a layer of pressure-sensitive adhesive on the multilayer reflective film. The main function of this layer of pressure-sensitive adhesive is to firmly attach the reinforcing layer 403 to be added to the multilayer reflective film. The coating thickness of the pressure-sensitive adhesive is controlled to be 15 μm to ensure the adhesion effect without affecting the light transmittance.

[0101] In this embodiment, a transparent PET substrate is selected as the reinforcing layer 403, and the PET substrate is superimposed on the pressure-sensitive adhesive layer to ensure that there are no bubbles and wrinkles and the fit is firm. During the lamination process, a rolling device can be used to apply slight pressure to ensure the tightness between the PET substrate and the multilayer reflective film 3.

[0102] The heat insulating layer 401 is coated on the reinforcing layer 403 substrate. In this embodiment, indium tin oxide is used to give the film basic heat insulating properties. After coating, a drying process is performed using a heating drying device to volatilize the solvent in the heat insulating layer 401 and ensure that the coating is stably adhered.

[0103] After the heat insulation layer 401 is completely dried, an anti-ultraviolet layer 402 is coated thereon to block ultraviolet rays. In this embodiment, zinc oxide is used, which is a widely used inorganic ultraviolet blocking material, not only because it can effectively absorb UVA and UVB rays, but also because it can maintain a high degree of transparency in the coating. The nanoparticle form of zinc oxide can be evenly coated on the heat insulation layer 401 to form a transparent anti-ultraviolet protective layer, which does not affect the visual effect while providing strong UV protection. After coating, it is dried again to ensure the uniformity and adhesion of the layer.

[0104] After the UV protection layer 402 is dried, a layer of pressure-sensitive adhesive is evenly coated on the UV protection layer 402. The main function of this layer of pressure-sensitive adhesive is to firmly attach the reinforcing layer 403 to be added to the UV protection layer 402. The coating thickness of the pressure-sensitive adhesive is controlled to be 15 μm to ensure the adhesion effect without affecting the light transmittance.

[0105] In this embodiment, a transparent PET substrate is selected as the reinforcing layer 403, and the PET substrate is superimposed on the pressure-sensitive adhesive layer to ensure that there are no bubbles and wrinkles, and the fit is firm. During the lamination process, a rolling device can be used to apply slight pressure to ensure the tightness between the PET substrate and the UV protection layer 402.

[0106] On the basis of the above PET substrate, a heat insulation layer 401, an anti-ultraviolet layer 402, a pressure-sensitive adhesive and a PET reinforcement layer 403 are repeatedly prepared.

[0107] An anti-fog layer 404 is coated on the PET substrate. The anti-fog layer 404 can effectively prevent fogging caused by moisture and maintain the clarity of the film. In this embodiment, the anti-fog material is a nano-silicon dioxide coating. Nano-SiO2 particles are used to increase the hydrophilicity of the film surface, so that water vapor forms a uniform water film on the surface instead of droplets. After coating, the anti-fog coating is cured by heating and drying equipment to ensure stable adhesion of the material.

[0108] The protective layer 5 is covered on the anti-fog layer 404 to prevent the anti-fog adhesive from being contaminated and damaged before packaging, transportation and installation. In this embodiment, the protective layer 5 is an electrostatic film, and in this embodiment, a PE film is used. In other embodiments, a PVC film or a PPS film can also be used.

[0109] After the protective layer 5 is covered, the adhesive layer 2 is coated on the back of the multilayer reflective film 3. In this embodiment, a pressure-sensitive adhesive is used as the adhesive layer 2, in which oxybenzone is added as a UV absorption barrier material, which can effectively absorb UVA and UVB light and is added to the transparent pressure-sensitive adhesive to provide UV protection without affecting transparency.

[0110] The surface of the pressure-sensitive adhesive layer is covered with an isolation layer 1, which is a PET film in this embodiment, for easy winding and cutting. This isolation layer 1 can protect the pressure-sensitive adhesive from contamination before packaging, transportation and installation, and prevent the pressure-sensitive adhesive from losing its viscosity.

[0111] The multilayer reflective film of the prior art and the sunshade film with a multilayer structure prepared in Example 4 of the present invention were tested in the range of 550nm to 750nm (green to red light waves in visible light) and in the range of 700nm to 780nm (end of the infrared region).

[0112] The results are as follows Figure 7-10 as shown in .

[0113] Analysis in the range of 700nm to 780nm.

[0114] Internal reflection spectrum (from the perspective of people inside the car, Figure 7 ):

[0115] In the absence of a composite functional layer, there is a clear reflection peak in this range, which means that people inside the car can see the color reflected by the multilayer film, which may cause glare or other visual interference.

[0116] After adding the composite functional layers, the reflection peak in this interval is significantly reduced, which shows that these layers effectively reduce internal reflections and thus alleviate the discomfort of people in the car, such as dizziness or visual disorders.

[0117] External reflection spectrum (perspective of people outside the vehicle, Fig. 9 ):

[0118] The reflection peak intensity in this range did not change significantly before and after the addition of the composite functional layer, which shows that although the visual environment inside the car has been optimized, the appearance of the multilayer film and its reflection effect on the external environment have not been affected.

[0119] Analysis in the range of 550nm to 750nm.

[0120] Internal reflection spectrum (from the perspective of people inside the car, Figure 8 ):

[0121] In the absence of a composite functional layer, an obvious reflection peak is also observed in this range, covering a wider visible spectrum and having a wider impact on the lighting and color of the interior environment of the vehicle.

[0122] After adding the composite functional layer, the reflection peak is significantly reduced, effectively reducing the intensity of light entering the car from the window, alleviating light pollution and related discomfort.

[0123] External reflection spectrum (perspective of people outside the vehicle, Fig.10 ):

[0124] For observers outside the vehicle, the addition of the composite functional layer does not negatively affect the reflection spectrum in the range of 550nm to 750nm, ensuring that the appearance of the vehicle will not be damaged by technological improvements. This enables the selection of bidirectional spectra of the glass reflecting inward (inside the vehicle) and outward (outside the vehicle).

[0125] The absorption spectrum of the multilayer reflective film in the prior art and the sunshade film of Example 4 of the present invention was tested. The test results are as follows: Fig.11 shown.

[0126] J curve: original absorption spectrum of the prior art multilayer reflective film

[0127] Low absorption region: In the visible light range of 500nm to 700nm, the J curve shows relatively low absorption, which indicates that the original multilayer reflective film blocks less light in this region, which may lead to more visible light transmission. This characteristic can maintain good light transmittance, but the effect in heat insulation and light shielding is relatively limited.

[0128] Performance in the infrared region: In the near-infrared range of 950nm to 1400nm, the J curve also shows low absorption, which means that in this band, the heat insulation ability of the film is weak, and a large amount of infrared radiation can pass through the film into the car.

[0129] K curve: Absorption spectrum after adding sunshade and PET layers

[0130] Enhanced absorption performance: The K curve shows significantly enhanced absorption performance in the entire region from 500nm to 1400nm, especially in the visible light and near-infrared light regions. This shows that the addition of the functional layer effectively enhances the light-shielding and heat-insulating properties of the film, and can more effectively block light and heat energy. The total solar energy blocking rate tested reached more than 60%.

[0131] Improved light-shielding and heat-insulating effects: Due to the increase in the absorption peak, this structural design significantly improves the multilayer film's ability to block visible light and infrared radiation, which is very beneficial for improving the comfort of the car's interior and protecting the interior from UV and heat damage.

[0132] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A sunshade film with a multi-layer structure, characterized in that: From front to back, it comprises, in sequence, an isolation layer (1), an adhesive layer (2), a multilayer reflective film (3), a composite functional layer (4) and a protective layer (5); the composite functional layer (4) comprises at least one of a heat insulation layer (401), an ultraviolet protection layer (402), a reinforcement layer (403), an anti-fog layer (404) and an anti-reflection layer (405); and the adhesive layer (2) is transparent.

2. The sunshade film with a multi-layer structure according to claim 1, characterized in that: The isolation layer (1) is one of a PE release film, a PET release film, a silicone release film and a polyvinyl alcohol film.

3. The sunshade film with a multi-layer structure according to claim 1, characterized in that: The adhesive layer (2) is a pressure-sensitive adhesive.

4. The sunshade film with a multi-layer structure according to claim 1 or 3, characterized in that: The adhesive layer (2) contains a transparent ultraviolet absorbing barrier material.

5. The sunshade film with a multi-layer structure according to claim 1, characterized in that: The heat insulation layer (401) is made of one of metal oxide and nano ceramic material.

6. The sunshade film with a multi-layer structure according to claim 1, characterized in that: The protective layer (5) is one of epoxy resin, polyurethane and PE protective film.

7. The sunshade film with a multi-layer structure according to claim 1, characterized in that: The anti-reflection layer (405) is made of nano-particle material and is coated on the heat insulation layer (401) and / or the UV protection layer (402).

8. The sunshade film with a multi-layer structure according to claim 1, characterized in that: The thickness of the reinforcing layer (403) is ≥50 μm; the thickness of the bonding layer (2) is 5-10 μm.

9. The sunshade film with a multi-layer structure according to claim 1, characterized in that: The reinforcement layer (403) is a PET film.

10. A method for preparing the sunshade film having a multi-layer structure as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1: Select a multilayer reflective film as a substrate and coat one side with a composite functional layer; S2: providing a protective layer on the composite functional layer; S3: coating an adhesive layer on the other side of the multilayer reflective film; S4: Covering the adhesive layer with an isolation layer.

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