Vehicle-mounted flexible optical conductive film in wide temperature range and preparation method thereof

Abstract

The application discloses a kind of vehicle-mounted wide temperature range flexible optical conductive film and preparation method thereof, belong to conductive film technical field.The conductive film includes sequentially stacked flexible transparent substrate, optical matching transition layer, embedded wide temperature range composite conductive layer and weather-resistant encapsulation protective layer;Embedded wide temperature range composite conductive layer is composite conductive system with continuous interpenetrating network structure, including crosslinked conductive polymer matrix, one-dimensional metal nanowire with one-dimensional linear nanostructure and two-dimensional conductive nanosheet with two-dimensional planar sheet nanostructure;Optical matching transition layer realizes the continuous refractive index gradient of 1.50 to 1.62 by the film thickness direction gradient distribution of high refractive index inorganic component and low refractive index organic component.The preparation process of the application is adapted to roll-to-roll mass production, and the prepared film can consider optical performance, conductive performance, flexibility and wide temperature range stability, excellent weather resistance, and can meet the use demand of vehicle-mounted severe working conditions.

Description

Technical Field

[0001] This invention relates to the field of conductive thin film technology, specifically to a vehicle-mounted wide-temperature-range flexible optical conductive thin film and its preparation method. Background Technology

[0002] With the rapid development of in-vehicle smart cockpit technology, the demand for optical conductive films is continuously increasing in scenarios such as curved in-vehicle displays, intelligent dimming windows, and irregularly shaped touch interactions. In-vehicle applications involve harsh conditions such as alternating high and low temperatures, humid and hot environments, long-term sunlight exposure, and vibration and shock, placing extremely high demands on the conductive films' flexibility, conductivity stability over a wide temperature range, optical uniformity, weather resistance, and structural reliability.

[0003] Existing optical conductive films used in automotive applications still have several technical shortcomings: Firstly, traditional indium tin oxide conductive films are inherently brittle, and their conductivity is prone to significant degradation after bending, making them unsuitable for applications involving curved surfaces and irregular structures in vehicles. Furthermore, their resistance drift is significant in a wide temperature range, making it difficult to meet the stable operation requirements of vehicles under high and low temperature conditions. Secondly, in single metal nanowire conductive films, the contact resistance at the junctions between nanowires is high. Under high and low temperature environments, thermal expansion and contraction of the material can easily lead to the separation of the junctions, causing significant fluctuations in conductivity. At the same time, metal nanowires are prone to oxidation and corrosion, have insufficient weather resistance, and their performance degrades rapidly during long-term use. Furthermore, nanowires are prone to agglomeration, resulting in poor optical uniformity of the film. Third, the conductivity of pure conductive polymer conductive films is insufficient to meet the requirements of automotive touch control and conductivity. In low-temperature environments, the polymer molecular chains are prone to freezing, causing a sharp drop in conductivity and making them unsuitable for automotive use in a wide temperature range. Fourth, existing composite conductive films have refractive index differences between multiple functional layers, which can easily cause interface light reflection, increase optical loss, and affect the clarity of vehicle displays. At the same time, the interlayer adhesion is insufficient, and interlayer peeling is prone to occur during bending and high and low temperature impacts, resulting in insufficient structural reliability and inability to adapt to the harsh long-term use conditions of vehicles. Summary of the Invention

[0004] The present invention aims to solve the problems mentioned in the background art by providing a vehicle-mounted wide-temperature-range flexible optical conductive film and its preparation method.

[0005] The specific technical solution is as follows: A flexible optical conductive film for automotive applications with a wide temperature range includes a flexible transparent substrate, an optical matching transition layer, an embedded wide temperature range composite conductive layer, and a weather-resistant encapsulation protective layer, which are sequentially stacked. The embedded wide-temperature-range composite conductive layer is a composite conductive system with a continuous interpenetrating network structure. The composite conductive system includes a cross-linked conductive polymer matrix, one-dimensional metal nanowires and two-dimensional conductive nanosheets uniformly dispersed in the cross-linked conductive polymer matrix. The one-dimensional metal nanowires and two-dimensional conductive nanosheets form an overlapping and interconnected three-dimensional conductive network in the cross-linked conductive polymer matrix. The three-dimensional conductive network is partially embedded inside the cross-linked conductive polymer matrix and partially exposed on the surface of the cross-linked conductive polymer matrix.

[0006] As a preferred embodiment of the present invention, the flexible transparent substrate is made of a wide temperature range optical grade polymer film, the thickness of which is 10 μm to 100 μm, the glass transition temperature is not lower than 120°C, the light transmittance in the visible light band is not lower than 92%, and the haze is not higher than 0.5%.

[0007] In a preferred embodiment of the present invention, the optical matching transition layer is an organic-inorganic hybrid refractive index gradient layer. The refractive index of the optical matching transition layer gradually changes from 1.50 to 1.62 along the direction from near the flexible transparent substrate to near the embedded wide-temperature-range composite conductive layer through a gradient distribution of high-refractive-index inorganic components and low-refractive-index organic components in the film thickness direction. The thickness of the optical matching transition layer is 50 nm to 200 nm, and the light transmittance in the visible light band is not less than 98%. The high-refractive-index inorganic component is one or more of silane coupling agent modified nano-silica sol, nano-zirconia, and titanate refractive index modifier, and the low-refractive-index organic component is one or more of acrylate prepolymer and fluorinated acrylate prepolymer. Spontaneous gradient migration in the wet film state is achieved through the difference in surface energy of the components, and the gradient distribution is locked by a step-by-step curing process, thereby achieving a continuous gradient of refractive index and eliminating Fresnel reflection at the interlayer interface.

[0008] In a preferred embodiment of the present invention, the cross-linked conductive polymer matrix is ​​a cross-linked interpenetrating network of a poly(3,4-ethylenedioxythiophene) conductive polymer modified by dual doping. The dual doping modification employs a composite doping of a sulfonic acid dopant and a nonionic wide-temperature-range stabilizer. The mass ratio of the sulfonic acid dopant to the nonionic wide-temperature-range stabilizer is 5:1 to 10:1. The conductivity of the cross-linked conductive polymer matrix is ​​not less than 100 S / cm, and the conductivity fluctuation range within the temperature range of -40℃ to 125℃ is not higher than 15%.

[0009] As a preferred embodiment of the present invention, the one-dimensional metal nanowire is a silver nanowire or a gold nanowire with a one-dimensional linear nanostructure. The aspect ratio of the one-dimensional metal nanowire is not less than 1000, the diameter is 15 nm to 30 nm, and the length is 30 μm to 50 μm. These size parameters are used to define the one-dimensional linear morphology of the one-dimensional metal nanowire to ensure that a continuous overlapping linear conductive path is formed between the nanowires. The mass percentage of the one-dimensional metal nanowire in the embedded wide-temperature-range composite conductive layer is 15% to 35%.

[0010] As a preferred embodiment of the present invention, the two-dimensional conductive nanosheet is a few-layer graphene nanosheet or MXene nanosheet with a two-dimensional planar sheet-like nanostructure. The diameter of the two-dimensional conductive nanosheet is 1 μm to 5 μm, the thickness is 1 nm to 5 nm, and the ratio of the lateral dimension to the thickness is not less than 200. This size parameter is used to define the two-dimensional planar sheet-like morphology of the two-dimensional conductive nanosheet to ensure that the two-dimensional conductive nanosheet fills the overlap gap of the one-dimensional metal nanowire and reduces the contact resistance. The mass percentage of the two-dimensional conductive nanosheet in the embedded wide-temperature-range composite conductive layer is 2% to 8%.

[0011] In a preferred embodiment of the present invention, the weather-resistant encapsulation protective layer is a cross-linked fluorinated acrylate polymer layer. The weather-resistant encapsulation protective layer contains dispersed ultraviolet absorbers and hindered phenolic antioxidants. The total mass percentage of the ultraviolet absorbers and hindered phenolic antioxidants is 0.5% to 3%. The thickness of the weather-resistant encapsulation protective layer is 1 μm to 5 μm. The light transmittance in the visible light band is not less than 90%, and the water vapor transmittance is not higher than 1 g / (m²). 2 •24h).

[0012] This invention also provides a method for preparing a flexible optical conductive film with a wide temperature range for automotive applications, comprising the following steps: Step 1: Pretreatment of flexible transparent substrate: The flexible transparent substrate is subjected to surface cleaning and plasma activation treatment to obtain the activated substrate; Step 2, Preparation of Optical Matching Transition Layer: An organic-inorganic hybrid coating liquid with a refractive index gradient and a surface energy differential design is coated on the activated substrate surface. After the wet film leveling completes the spontaneous gradient migration of components, it is pre-cured and thermally cured to lock the component gradient distribution in the film thickness direction, forming an optical matching transition layer with a refractive index that continuously varies from 1.50 to 1.62 from near the flexible transparent substrate to near the embedded wide temperature range composite conductive layer. Step 3: Preparation of embedded wide-temperature-range composite conductive layer: The cross-linked conductive polymer dispersion, one-dimensional metal nanowire dispersion, two-dimensional conductive nanosheet dispersion and cross-linking agent are mixed in proportion to obtain composite conductive coating liquid; the composite conductive coating liquid is coated on the surface of the optical matching transition layer and subjected to segmented thermosetting treatment to form embedded wide-temperature-range composite conductive layer. Step 4: Preparation of weather-resistant encapsulation protective layer: A fluorinated acrylate encapsulation coating liquid is coated on the surface of the embedded wide temperature range composite conductive layer, and then cured by ultraviolet light and heat to form a weather-resistant encapsulation protective layer, thus obtaining a vehicle-mounted wide temperature range flexible optical conductive film.

[0013] In a preferred embodiment of the present invention, in step three, the solid content of the composite conductive coating liquid is 3% to 8%, the coating method is slot coating or micro-gravure coating, and the segmented thermosetting treatment is pre-curing at 60°C to 70°C for 3 to 5 minutes, medium-temperature curing at 90°C to 110°C for 5 to 10 minutes, and high-temperature curing at 120°C to 130°C for 2 to 5 minutes.

[0014] In a preferred embodiment of the present invention, in step two, the organic-inorganic hybrid coating liquid is prepared by mixing nano-silica sol modified with silane coupling agent, acrylate prepolymer, refractive index modifier and photoinitiator in a certain proportion. The solid content of the coating liquid is 2% to 5%. The pre-curing treatment adopts low-energy ultraviolet light pre-curing with a curing energy of 300mJ / cm² to 500mJ / cm² to lock the component gradient distribution on the substrate side. The temperature of the thermal curing treatment is 100℃ to 120℃ and the time is 5min to 10min to complete the cross-linking and shaping of the entire film layer and form a stable refractive index continuously gradient structure.

[0015] The present invention has the following beneficial effects: 1. It achieves a balance between flexible bending performance, conductivity, and optical performance. By constructing a three-dimensional conductive network through the synergy of one-dimensional metal nanowires and two-dimensional conductive nanosheets, it ensures the excellent conductivity of the film while avoiding the problem of traditional conductive films being unable to balance high conductivity and high light transmittance. At the same time, the overall film has excellent flexible bending performance, which can adapt to the application requirements of various curved surfaces and irregular structures in automotive applications, and the performance does not significantly decrease after bending.

[0016] 2. Significantly improves the performance stability of the film in a wide temperature range environment. By using the cross-linked interpenetrating network structure of the cross-linked conductive polymer matrix, the spatial structure of the three-dimensional conductive network is fixed, which inhibits the deformation of polymer molecular chains and the migration of dopants under high and low temperature environments, avoids the breakage or separation of conductive pathways, and ensures that the conductivity of the film remains stable without significant fluctuations under the alternating high and low temperature environment of the vehicle.

[0017] 3. The optical transmission performance of the thin film has been optimized. By using an optical matching transition layer with a continuously varying refractive index, the interface reflection between multiple functional layers is eliminated, reducing optical loss during light transmission and ensuring excellent light transmission uniformity and low haze of the thin film. This will not negatively affect the clarity and display effect of the vehicle display.

[0018] 4. Improved weather resistance and service life of the film. The dense weather-resistant encapsulation protective layer blocks external moisture, corrosive substances and ultraviolet rays from eroding the internal conductive layer, avoiding oxidation and corrosion of conductive materials and aging of polymer system. At the same time, the embedded structure of conductive network further provides anti-oxidation protection for conductive materials, ensuring that the film can work stably for a long time in complex environments such as vehicle humidity and light, and extending its service life.

[0019] 5. Improved structural stability and reliability of the film: Through the interface adaptation design between functional layers, the interlayer adhesion is greatly improved, avoiding problems such as interlayer peeling and coating cracking under complex automotive conditions such as bending, high and low temperature impact, and vibration, thus ensuring the structural integrity and performance consistency of the film during long-term use.

[0020] 6. Adaptable to the needs of large-scale industrial production, the overall preparation process adopts a mature roll-to-roll coating process, which does not require complex vacuum evaporation equipment. The production process is highly controllable, the product consistency is high, and large-scale continuous production can be achieved. At the same time, the raw material system consists of commercially mature materials, which can control production costs while ensuring performance, and adapt to the needs of large-scale application in the automotive field. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the vehicle-mounted wide-temperature-range flexible optical conductive film provided in an embodiment of the present invention; Figure 2 This is a comparison chart of conductivity fluctuations in Examples 1-3 of the present invention; Figure 3 This is a biaxial graph showing the transmittance and haze of Embodiments 1-3 of the present invention.

[0022] In the attached image: 1. Flexible transparent substrate; 2. Optical matching transition layer; 3. Embedded wide temperature range composite conductive layer; 4. Weather-resistant encapsulation protective layer. Detailed Implementation

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this application. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0025] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0026] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Reference Figures 1-3 ,in: Figure 1 This diagram illustrates the structure of a flexible optical conductive film with a wide temperature range for automotive applications. Figure 2 The percentage fluctuations in conductivity of Examples 1-3 within the temperature range of -40℃ to 125℃ are shown (8.2%, 6.7%, and 12.3%), visually demonstrating the differences in stability over a wide temperature range. Figure 3 The bar chart shows the 550nm transmittance of Examples 1-3 (91.2% / 90.8% / 90.2%), and the line graph shows the corresponding haze (0.3% / 0.4% / 0.3%). The dual-axis scale synchronously presents the balance of optical performance.

[0028] The automotive-grade wide-temperature-range flexible optical conductive film provided in this application includes a flexible transparent substrate 1, an optical matching transition layer 2, an embedded wide-temperature-range composite conductive layer 3, and a weather-resistant encapsulation protective layer 4, which are stacked sequentially. The embedded wide-temperature-range composite conductive layer 3 is a composite conductive system with a continuous interpenetrating network structure. The composite conductive system includes a cross-linked conductive polymer matrix, one-dimensional metal nanowires and two-dimensional conductive nanosheets uniformly dispersed in the cross-linked conductive polymer matrix. The one-dimensional metal nanowires and two-dimensional conductive nanosheets form an overlapping and interconnected three-dimensional conductive network in the cross-linked conductive polymer matrix. The three-dimensional conductive network is partially embedded inside the cross-linked conductive polymer matrix and partially exposed on the surface of the cross-linked conductive polymer matrix.

[0029] A complete functional layer structure is constructed by sequentially stacking a flexible transparent substrate 1, an optical matching transition layer 2, an embedded wide-temperature-range composite conductive layer 3, and a weather-resistant encapsulation protective layer 4. The embedded wide-temperature-range composite conductive layer 3 adopts a three-dimensional conductive network formed by a cross-linked conductive polymer matrix, one-dimensional metal nanowires, and two-dimensional conductive nanosheets. The three-dimensional conductive network is partially embedded and partially exposed, which not only achieves a balance between conductivity and flexibility, but also improves the optical transparency and environmental adaptability of the film through the synergistic effect of each layer. This adapts to the complex usage requirements in automotive scenarios and solves the problem of balancing flexibility, conductivity stability, and optical performance in conventional conductive films.

[0030] Among them, the flexible transparent substrate 1 adopts a wide temperature range optical grade polymer film with a thickness of 10μm to 100μm, a glass transition temperature of not less than 120℃, a light transmittance of not less than 92% in the visible light band, and a haze of not more than 0.5%.

[0031] The flexible transparent substrate 1 employs a wide-temperature-range optical-grade polymer film with a defined thickness, providing stable flexible support for the entire film while adapting to high and low temperature variations in the automotive environment, making it less prone to thermal deformation or cracking. Excellent optical performance ensures smooth light transmission, avoiding any impact on the automotive display effect. The appropriate thickness balances flexibility and structural strength, providing a stable foundation for the subsequent attachment of functional layers and ensuring the overall structural integrity and optical consistency of the film.

[0032] The optical matching transition layer 2 is an organic-inorganic hybrid refractive index gradient layer. The refractive index of the optical matching transition layer 2 varies continuously from 1.50 to 1.62 along the direction from near the flexible transparent substrate 1 to near the embedded wide-temperature-range composite conductive layer 3, achieved through a gradient distribution of high-refractive-index inorganic components and low-refractive-index organic components in the film thickness direction. The thickness of the optical matching transition layer 2 is 50 nm to 200 nm, and its light transmittance in the visible light band is not less than 98%. The high-refractive-index inorganic components are one or more of the following: silane coupling agent modified nano-silica sol, nano-zirconia, and titanate refractive index modifier. The low-refractive-index organic components are one or more of the following: acrylate prepolymer and fluorinated acrylate prepolymer. Spontaneous gradient migration in the wet film state is achieved through the difference in surface energy of the components. Combined with a step-by-step curing process to lock the gradient distribution, this results in a continuous gradient of refractive index, eliminating Fresnel reflection at the interlayer interface.

[0033] The optical matching transition layer 2 adopts an organic-inorganic hybrid refractive index gradient design, which can effectively bridge the refractive index difference between the flexible transparent substrate 1 and the embedded wide-temperature-range composite conductive layer 3, reducing light reflection at the interlayer interface and lowering optical loss. The organic-inorganic hybrid material improves the density of the transition layer and its adhesion to adjacent layers. The good light transmittance further ensures the overall optical transmittance of the film, avoids light scattering caused by the superposition of multiple layers, and improves the clarity of the automotive display.

[0034] The organic-inorganic hybrid coating liquid, by mass, consists of: 20-40 parts of optical-grade silane coupling agent modified nano-silica sol with a solid content of 30%, 10-25 parts of acrylate prepolymer, 5-18 parts of titanate refractive index regulator, 0.5-2 parts of photoinitiator 1173, and optical-grade solvent to a total of 1000 parts. The solid content of the coating liquid is 2%-5%, and the refractive index range of the coating can be linearly controlled by adjusting the amount of titanate refractive index regulator added, achieving a continuous gradual change from 1.50 to 1.62.

[0035] Among them, photoinitiator 1173 is 2-hydroxy-2-methyl-1-phenyl-1-propanone, CAS number 7473-98-5.

[0036] The cross-linked conductive polymer matrix is ​​a cross-linked interpenetrating network of poly(3,4-ethylenedioxythiophene) conductive polymer modified by double doping. The double doping modification adopts a composite doping of sulfonic acid dopant and non-ionic wide-temperature stabilizer. The mass ratio of sulfonic acid dopant to non-ionic wide-temperature stabilizer is 5:1 to 10:1. The conductivity of the cross-linked conductive polymer matrix is ​​not less than 100 S / cm, and the conductivity fluctuation range in the temperature range of -40℃ to 125℃ is not higher than 15%.

[0037] The cross-linked conductive polymer matrix employs dual-doping modification and a cross-linked interpenetrating network structure, enhancing the conductivity of the polymer while suppressing dopant migration and molecular chain deformation under high and low temperature environments. This ensures the stability of the film's conductivity under different temperature conditions, meeting the requirements for wide-temperature-range automotive applications. A reasonable dopant ratio avoids the negative impact of excessive stabilizer on conductivity, while also improving the compatibility of the conductive polymer matrix with one-dimensional metal nanowires and two-dimensional conductive nanosheets, ensuring the continuity and stability of the three-dimensional conductive network.

[0038] Among them, the one-dimensional metal nanowires are silver nanowires or gold nanowires with one-dimensional linear nanostructures. The aspect ratio of the one-dimensional metal nanowires is not less than 1000, the diameter is 15nm to 30nm, and the length is 30μm to 50μm. The above size parameters are used to define the one-dimensional linear morphology of the one-dimensional metal nanowires to ensure that a continuous overlapping linear conductive path is formed between the nanowires. The mass ratio of the one-dimensional metal nanowires in the embedded wide temperature range composite conductive layer 3 is 15% to 35%.

[0039] One-dimensional metallic nanowires, using silver or gold nanowires with specific morphologies and proportions, possess excellent conductivity. Suitable morphologies enable effective interconnection between nanowires, forming continuous conductive pathways. A reasonable mass ratio ensures conductivity while avoiding excessive amounts that could negatively impact the film's optical transmittance and flexibility. This, combined with two-dimensional conductive nanosheets, further enhances the three-dimensional conductive network, improving overall conductivity and structural stability.

[0040] Among them, the two-dimensional conductive nanosheets are few-layer graphene nanosheets or MXene nanosheets with two-dimensional planar sheet-like nanostructures. The diameter of the two-dimensional conductive nanosheets is 1μm to 5μm, the thickness is 1nm to 5nm, and the ratio of the lateral dimension to the thickness is not less than 200. The above-mentioned size parameters are used to limit the two-dimensional planar sheet-like morphology of the two-dimensional conductive nanosheets, ensuring that the two-dimensional conductive nanosheets fill the overlapping gaps of the one-dimensional metal nanowires and reduce the contact resistance. The mass ratio of the two-dimensional conductive nanosheets in the embedded wide temperature range composite conductive layer 3 is 2% to 8%.

[0041] Two-dimensional conductive nanosheets, using few-layer graphene or MXene nanosheets, possess a sheet-like structure that fills the gaps between one-dimensional metal nanowires, reducing contact resistance and enhancing the connectivity of the conductive network. Appropriate size and thickness prevent nanosheet aggregation, ensuring uniform dispersion within the conductive polymer matrix. A suitable ratio of lateral size to thickness further optimizes the filling effect, while simultaneously enhancing the structural density of the composite conductive layer, improving moisture barrier properties, and indirectly improving the film's weather resistance.

[0042] The weather-resistant encapsulation protective layer 4 is a cross-linked fluorinated acrylate polymer layer. Ultraviolet absorbers and hindered phenolic antioxidants are dispersed within the weather-resistant encapsulation protective layer 4. The total mass percentage of the ultraviolet absorbers and hindered phenolic antioxidants is 0.5% to 3%. The thickness of the weather-resistant encapsulation protective layer 4 is 1 μm to 5 μm. The light transmittance in the visible light band is not less than 90%, and the water vapor transmittance is not higher than 1 g / (m²). 2 •24h).

[0043] The weather-resistant encapsulation protective layer 4 is made of cross-linked fluorinated acrylate polymer, which has excellent weather resistance and density, and can resist the corrosion of ultraviolet rays, moisture, dust and other substances in the automotive environment, protecting the internal conductive layer from damage. The addition of ultraviolet absorbers and hindered phenolic antioxidants slows down the aging rate of the film and extends its service life. The reasonable additive ratio ensures weather resistance without affecting the optical transmittance of the film. The good water vapor barrier ability further improves the stability of the conductive layer, ensuring that the film can work stably in the automotive environment for a long time.

[0044] Among them, the flexible transparent substrate 1 can be any one of optical-grade cyclic olefin polymer film, polyethylene terephthalate film, and polyethylene naphthalate film. Three types of commercially available mature materials for the flexible transparent substrate 1 have been identified, which reduces the difficulty of raw material selection and supply chain adaptation costs while fully meeting the original scheme's requirements for wide temperature range stability, high light transmittance, low haze, and flexible support.

[0045] The surface of the one-dimensional metal nanowires was modified with a silane coupling agent, which could be either γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane. This surface modification with a conventional silane coupling agent further improved the dispersion and compatibility of the metal nanowires in the cross-linked conductive polymer matrix, reduced the risk of nanowire aggregation, and ensured the uniformity of the three-dimensional conductive network film. Simultaneously, it slightly improved the interfacial bonding between the metal nanowires and the polymer matrix, optimizing the retention of conductivity after multiple bending of the film.

[0046] In the weather-resistant encapsulation protective layer 4, the mass ratio of UV absorber to hindered phenolic antioxidant is 2:1 to 3:1. This clarifies the optimal ratio of UV absorber to hindered phenolic antioxidant, enabling them to form a synergistic anti-aging effect in the encapsulation layer. Without affecting the film's optical transmittance, this further slows down the UV and thermo-oxidative aging rates of the polymer system, slightly extending the film's service life under high-temperature automotive lighting conditions.

[0047] This application also provides a method for preparing a flexible optical conductive film with a wide temperature range for vehicle use, comprising the following steps: Step 1: Pretreatment of flexible transparent substrate 1: The flexible transparent substrate 1 is subjected to surface cleaning and plasma activation treatment to obtain the activated substrate; Step 2, Preparation of Optical Matching Transition Layer 2: An organic-inorganic hybrid coating liquid with a gradually changing refractive index is coated on the activated substrate surface, and after pre-curing and thermal curing treatment, optical matching transition layer 2 is formed; Step 3: Preparation of embedded wide-temperature-range composite conductive layer 3: The cross-linked conductive polymer dispersion, one-dimensional metal nanowire dispersion, two-dimensional conductive nanosheet dispersion and cross-linking agent are mixed in proportion to obtain composite conductive coating liquid; the composite conductive coating liquid is coated on the surface of optical matching transition layer 2, and after segmented thermosetting treatment, embedded wide-temperature-range composite conductive layer 3 is formed. Step 4: Preparation of weather-resistant encapsulation protective layer 4: A fluorinated acrylate encapsulation coating liquid is coated on the surface of the embedded wide temperature range composite conductive layer 3, and then cured by ultraviolet light and heat to form a weather-resistant encapsulation protective layer 4, thus obtaining a vehicle-mounted wide temperature range flexible optical conductive film.

[0048] The fabrication method follows a logically coherent process, including substrate pretreatment, preparation of the optical matching transition layer 2, preparation of the composite conductive layer, and preparation of the encapsulation protective layer. Substrate pretreatment enhances surface activity, strengthens the adhesion of subsequent layers, and prevents interlayer delamination. The fabrication steps of each functional layer precisely correspond to the product structure, ensuring that the performance of each layer meets standards. The overall process can stably produce flexible optical conductive films that meet automotive requirements, guaranteeing product consistency and performance stability, and reducing the defect rate during mass production.

[0049] In step three, the solid content of the composite conductive coating liquid is 3% to 8%, and the coating method is slot coating or micro-gravure coating. The segmented thermosetting treatment is as follows: pre-curing at 60℃ to 70℃ for 3 to 5 minutes, medium-temperature curing at 90℃ to 110℃ for 5 to 10 minutes, and high-temperature curing at 120℃ to 130℃ for 2 to 5 minutes.

[0050] The solid content and coating method of the composite conductive coating liquid are adapted to the preparation requirements of the composite conductive layer, ensuring uniform coating and avoiding defects such as uneven coating and pinholes, and ensuring uniform dispersion of conductive materials in the coating. The segmented thermosetting process gradually completes solvent evaporation and cross-linking reaction, avoiding structural defects caused by excessive curing speed. At the same time, it realizes the design of partially embedded and partially exposed three-dimensional conductive network, improving the adhesion between the conductive layer and adjacent layers, ensuring conductivity and flexibility, and adapting to the bending requirements of automotive films.

[0051] In step two, the organic-inorganic hybrid coating solution is prepared by mixing silane coupling agent-modified nano-silica sol, acrylate prepolymer, refractive index modifier, and photoinitiator in a certain proportion. The solid content of the coating solution is 2% to 5%, and the pre-curing treatment is performed by ultraviolet light curing with a curing energy of 300 mJ / cm². 2 Up to 500mJ / cm 2 The temperature for heat curing is 100℃ to 120℃, and the time is 5 min to 10 min.

[0052] The design of the composition of the optical matching transition layer 2 coating liquid ensures the achievement of a refractive index gradient effect. Appropriate solid content is suitable for the nanometer-scale thickness requirements of the coating, guaranteeing uniform transition layer thickness. UV pre-curing rapidly sets the coating, while thermal curing further completes the organic-inorganic hybrid reaction, forming a dense and stable transition layer. This improves the adhesion and optical properties of the transition layer, reduces interlayer reflection, and provides a good foundation for the subsequent preparation of the composite conductive layer, ensuring that the overall film's optical and structural properties meet the standards.

[0053] In step one, the plasma activation treatment is oxygen plasma activation treatment, with a treatment power of 300W to 800W and a treatment time of 30s to 120s. The specific type of plasma activation treatment and mass-production-friendly process parameters are clearly defined, which can stably control the surface activity and micro-roughness of the flexible transparent substrate 1. Without damaging the optical properties of the substrate, it further improves the interlayer adhesion between the substrate and the optical matching transition layer 2, and reduces the defect rate of coating peeling during mass production.

[0054] In step two, the organic-inorganic hybrid coating liquid is applied using any one of the following methods: gravure coating, slot coating, or spin coating. This clarifies three possible coating methods for the optical matching transition layer 2, all of which can achieve uniform film formation with nanoscale thickness coatings. These methods are adaptable to different equipment configurations for laboratory pilot-scale, pilot-scale, and large-scale mass production scenarios, and can be implemented without significant modifications to existing optical coating production lines, thus improving the equipment adaptability and production flexibility of the preparation process.

[0055] In addition, this application also provides the following embodiments and comparative examples.

[0056] I. Example: Example 1: Benchmark Performance Automotive Wide Temperature Range Flexible Optical Conductive Thin Film 1. Specific formula and process parameters (1) Flexible transparent substrate 1: Optical grade cyclic olefin polymer film, thickness 50μm, glass transition temperature 145℃, 550nm visible light transmittance 93.2%, haze 0.2%.

[0057] (2) Optical matching transition layer 2: Organic-inorganic hybrid refractive index gradient layer, the refractive index is continuously gradient from 1.51 to 1.61 along the direction from near the substrate to near the conductive layer through the thickness gradient distribution of high refractive index inorganic components and low refractive index organic components, the thickness is 120 nm, and the transmittance of visible light at 550 nm is 98.5%; the liquid-solid content of the coating is 3.5%, and it is prepared by mixing silane coupling agent modified nano silica sol, acrylate prepolymer, titanate refractive index modifier, and photoinitiator 1173; the pre-curing is carried out by low-energy ultraviolet light curing, with a curing energy of 400 mJ / cm 2It is used to lock the component gradient distribution on the substrate side; the thermosetting temperature is 110℃ and the time is 8min, which is used to complete the cross-linking and shaping of the entire film layer.

[0058] Among them, the optical matching transition layer 2 liquid has the following composition by mass: Silane coupling agent modified nano silica sol (γ-aminopropyltriethoxysilane modified, solid content 30%, dispersed in anhydrous ethanol, particle size 5-8nm): 32 parts; Optical grade aliphatic polyurethane acrylate prepolymer (low functionality, refractive index nD=1.51): 18 parts; Titanate refractive index modifier (diisopropoxybis(acetylacetone) titanate, CAS No. 17927-72-9, commercially available brand DuPont TyzorAA): 8 parts; Photoinitiator 1173: 1.2 parts; Optical grade anhydrous ethanol: 940.8 parts; The total solids content of the formulation is 3.5%; after leveling the wet film, a continuous gradual change in refractive index of 1.51 to 1.61 can be achieved along the film thickness direction, and the transmittance of 550nm visible light is 98.5%.

[0059] (3) Embedded wide-temperature-range composite conductive layer 3: Cross-linked conductive polymer matrix: dual-doped modified poly3,4-ethylenedioxythiophene-polystyrene sulfonate, with camphor sulfonic acid as the sulfonic acid dopant and polyethylene glycol dimethyl ether as the nonionic wide-temperature stabilizer, with a mass ratio of 7.5:1. The matrix conductivity is 320 S / cm, and the conductivity fluctuates by 8.2% in the range of -40℃ to 125℃.

[0060] One-dimensional metal nanowires: Silver nanowires with a one-dimensional linear nanostructure, 20 nm in diameter, 40 μm in length, and an aspect ratio of 2000, accounting for 25% of the mass in the composite conductive layer.

[0061] Two-dimensional conductive nanosheets: few-layer graphene nanosheets with a two-dimensional planar sheet-like nanostructure, with a sheet diameter of 3 μm, a thickness of 3 nm, a lateral dimension to thickness ratio of 1000, and a mass percentage of 5% in the composite conductive layer.

[0062] Preparation process: The liquid-solid content of the composite conductive coating is 5.5%, and the coating method is slot coating; the segmented thermosetting process is as follows: pre-curing at 65℃ for 4 min, medium-temperature curing at 100℃ for 7 min, and high-temperature curing at 125℃ for 3 min.

[0063] (4) Weather-resistant encapsulation protective layer 4: Cross-linked fluorinated acrylate polymer layer, 3μm thick, 92.1% transmittance of visible light at 550nm, and 0.3g / (m²) water vapor transmittance. 2•24h); Benzotriazole UV absorber UV-327 and hindered phenolic antioxidant 1010 are dispersed in the layer, with a total mass ratio of 1.8%.

[0064] 2. Technical effects: This embodiment achieves a comprehensive balance of optical performance, conductivity, flexibility, wide-temperature stability, and weather resistance through the synergistic cooperation of a four-layer stacked structure. The optical matching transition layer 2 eliminates refractive index differences between adjacent layers, preventing interface light reflection and ensuring high overall light transmittance and low haze of the film. The dual-doped cross-linked conductive polymer matrix provides a stable supporting structure for the conductive network, suppressing conductivity fluctuations under high and low temperature environments. The three-dimensional conductive network, synergistically constructed from one-dimensional metal nanowires and two-dimensional conductive nanosheets, ensures efficient conductive pathways while maintaining adhesion and conductivity stability with upper and lower layers through a partially embedded and partially exposed structure. The weather-resistant encapsulation layer effectively blocks moisture and ultraviolet radiation, delaying film aging. The overall solution is fully adaptable to the wide-temperature-range automotive environment, and its bending performance and weather resistance meet the stringent requirements of automotive applications.

[0065] Example 2: High weather resistance and high flexibility automotive-grade wide temperature range flexible optical conductive film 1. Specific formula and process parameters (1) Flexible transparent substrate 1: Optical grade colorless transparent polyimide film, thickness 25μm, glass transition temperature 220℃, 550nm visible light transmittance 92.5%, haze 0.4%.

[0066] (2) Optical matching transition layer 2: Organic-inorganic hybrid refractive index gradient layer, the refractive index is continuously gradient from 1.52 to 1.62 along the direction from near the substrate to near the conductive layer, through the film thickness gradient distribution of high refractive index inorganic components and low refractive index organic components, the thickness is 80nm, and the transmittance of 550nm visible light is 98.2%; the liquid solid content of the coating is 2.5%, and it is prepared by mixing silane coupling agent modified nano silica sol, fluorinated acrylate prepolymer, nano zirconium oxide refractive index modifier, and photoinitiator TPO; the pre-curing adopts low energy ultraviolet light curing, curing energy is 350mJ / cm², which is used to lock the component gradient distribution on the substrate side; the thermal curing temperature is 105℃ and the time is 10min, which is used to complete the cross-linking and shaping of the entire film layer.

[0067] Among them, the optical matching transition layer 2 liquid has the following composition by mass: Silane coupling agent modified nano silica sol (γ-glycidyl etheroxypropyltrimethoxysilane modified, solid content 30%, propylene glycol methyl ether acetate PMA dispersion, particle size 3-5nm): 25 parts; Optical grade fluorinated acrylate prepolymer (refractive index nD=1.49, weather resistant and low yellowing): 12 parts; Titanate refractive index modifier (isopropyltris(acryloyloxy)titanate, CAS No. 103544-56-5, commercially available brand Kentian KR-7TS): 12 parts; Photoinitiator 1173: 0.8 parts; Optical grade propylene glycol methyl ether acetate (PMA): 950.2 parts; The total solids content of the formulation is 2.5%; after leveling the wet film, a continuous gradual change in refractive index of 1.52 to 1.62 can be achieved along the film thickness direction, with a 550nm visible light transmittance of 98.2%, and better weather resistance, making it suitable for the high flexibility and high weather resistance requirements of extreme automotive working conditions.

[0068] (3) Embedded wide-temperature-range composite conductive layer 3: Cross-linked conductive polymer matrix: Double-doped modified poly3,4-ethylenedioxythiophene-polystyrene sulfonate, with dodecylbenzenesulfonic acid as the sulfonic acid dopant and fluorinated polyether polyol as the nonionic wide-temperature stabilizer, with a mass ratio of 9:1. The matrix conductivity is 280 S / cm, and the conductivity fluctuation is 6.7% in the range of -40℃ to 125℃. One-dimensional metal nanowires: gold nanowires with a one-dimensional linear nanostructure, 25 nm in diameter, 45 μm in length, aspect ratio of 1800, and 32% of the mass in the composite conductive layer.

[0069] Two-dimensional conductive nanosheets: Ti3C2T with a two-dimensional planar sheet-like nanostructure x MXene nanosheets, with a diameter of 4 μm and a thickness of 2 nm, have a lateral dimension to thickness ratio of 2000 and account for 7% of the mass of the composite conductive layer.

[0070] Preparation process: The liquid-solid content of the composite conductive coating is 4%, and the coating method is micro-gravure coating; the segmented thermosetting process is as follows: pre-curing at 60℃ for 5 min, medium-temperature curing at 95℃ for 10 min, and high-temperature curing at 120℃ for 5 min.

[0071] (4) Weather-resistant encapsulation protective layer 4: cross-linked fluorinated acrylate polymer layer, 2μm thick, 91.5% transmittance of visible light at 550nm, and 0.2g / (m²) water vapor transmittance. 2 •24h); Benzotriazole UV absorber UV-328 and hindered phenolic antioxidant 1076 are dispersed in the layer, with a total mass ratio of 2.5%.

[0072] 2. Technical Effects This embodiment is optimized for the extreme environments and high-frequency flexible bending requirements of automotive applications. The high glass transition temperature of the polyimide substrate further enhances the film's high-temperature resistance and deformation resistance, while the thinner substrate significantly improves its flexible bending performance. The three-dimensional conductive network constructed by the synergistic interaction of chemically stable gold nanowires and MXene nanosheets further reduces contact resistance and improves the network's oxidation resistance and wide-temperature stability. A higher proportion of weather-resistant additives and a fluorine-containing encapsulation system significantly enhances the film's resistance to damp heat aging. The film in this embodiment exhibits superior performance stability in extreme high and low temperature environments, high-frequency bending scenarios, and long-term damp heat environments, making it perfectly suited for applications with extremely high requirements for flexibility and weather resistance, such as automotive curved displays and smart cockpits.

[0073] Example 3: Mass Production of Economical Automotive Wide-Temperature Flexible Optical Conductive Thin Film 1. Specific formula and process parameters (1) Flexible transparent substrate 1: Optical grade cyclic olefin polymer film, thickness 75μm, glass transition temperature 135℃, 550nm visible light transmittance 92.8%, haze 0.3%.

[0074] (2) Optical matching transition layer 2: Organic-inorganic hybrid refractive index gradient layer, the refractive index is continuously gradient from 1.50 to 1.60 along the direction from near the substrate to near the conductive layer through the film thickness gradient distribution of high refractive index inorganic components and low refractive index organic components, the thickness is 180nm, and the transmittance of visible light at 550nm is 98.1%; the liquid-solid content of the coating is 4.5%, and it is prepared by mixing silane coupling agent modified nano silica sol, acrylate prepolymer, titanate refractive index modifier, and photoinitiator 184; the pre-curing is carried out by low-energy ultraviolet light curing, with a curing energy of 450mJ / cm 2 It is used to lock the component gradient distribution on the substrate side; the thermosetting temperature is 115℃ and the time is 6min, which is used to complete the cross-linking and shaping of the entire film layer.

[0075] Among them, the optical matching transition layer 2 liquid has the following composition by mass: Silane coupling agent modified nano-silica sol (industrial grade optical type, solid content 30%, ethanol / PMA mixed dispersion): 38 parts; Optical grade epoxy acrylate prepolymer (refractive index nD=1.52, mass production general type): 22 parts; Titanate refractive index modifier (silane-modified nano-titanium dioxide dispersion, commercially available brand name Xuancheng Jingrui JR-Ti01-AC): 15 parts; Photoinitiator 1173: 1.5 parts; Optical grade anhydrous ethanol + PMA mixed solvent (mass ratio 1:1): 923.5 parts; The total solids content of the formulation is 4.5%; after leveling the wet film, a continuous gradual change in refractive index of 1.50 to 1.60 can be achieved along the film thickness direction, with a 550nm visible light transmittance of 98.1%. The raw material cost is low and it is suitable for roll-to-roll mass production.

[0076] (3) Embedded wide-temperature-range composite conductive layer 3: Cross-linked conductive polymer matrix: dual-doped modified poly3,4-ethylenedioxythiophene-polystyrene sulfonate, with camphor sulfonic acid as the sulfonic acid dopant and polypropylene glycol as the nonionic wide-temperature stabilizer, with a mass ratio of 5.5:1. The matrix conductivity is 180 S / cm, and the conductivity fluctuates by 12.3% in the range of -40℃ to 125℃.

[0077] One-dimensional metal nanowires: Silver nanowires with a one-dimensional linear nanostructure, 30 nm in diameter, 30 μm in length, and an aspect ratio of 1000, accounting for 18% of the mass in the composite conductive layer.

[0078] Two-dimensional conductive nanosheets: Ti3C2T with a two-dimensional planar sheet-like nanostructure x MXene nanosheets, with a diameter of 2 μm and a thickness of 4 nm, have a lateral dimension to thickness ratio of 500 and account for 3% of the mass of the composite conductive layer.

[0079] Preparation process: The liquid-solid content of the composite conductive coating is 7%, and the coating method is slot coating; the segmented thermosetting process is as follows: pre-curing at 70℃ for 3 min, medium-temperature curing at 105℃ for 6 min, and high-temperature curing at 130℃ for 2 min.

[0080] (4) Weather-resistant encapsulation protective layer 4: cross-linked fluorinated acrylate polymer layer, 4μm thick, 90.8% transmittance of visible light at 550nm, and 0.6g / (m²) water vapor transmittance. 2 •24h); Benzophenone-based UV absorber UV-9 and hindered phenolic antioxidant 168 are dispersed in the layer, with a total mass ratio of 0.8%.

[0081] 2. Technical Effects This embodiment is optimized for industrial mass production needs. By optimizing the raw material ratio, the amount of precious metal nanowires and high-performance additives is reduced, significantly lowering raw material costs. Simultaneously, the coating and curing process parameters are optimized, shortening curing time and improving production efficiency, making it suitable for roll-to-roll mass production. The film in this embodiment maintains excellent optical properties, electrical conductivity stability, wide temperature range adaptability, and weather resistance, fully meeting the requirements of typical automotive applications. It also boasts extremely high cost-effectiveness for mass production, making it suitable for widespread applications such as automotive central control screens and smart windows.

[0082] II. Comparative Example Comparative Example 1: Conductive thin film without optical matching transition layer 2 1. Specific formula and process parameters Except for the removal of the optical matching transition layer 2 and the direct coating of the composite conductive coating liquid on the surface of the activated COP substrate, all other raw materials, formulation parameters, and preparation processes are completely consistent with those in Example 1.

[0083] 2. Technical Effects This comparative example lacks an optical matching transition layer 2, which fails to eliminate the refractive index difference between the flexible transparent substrate 1 and the composite conductive layer. This results in significant light reflection at the interlayer interface, drastically reducing the overall light transmittance of the film, increasing haze, and severely affecting the clarity of the automotive display. At the same time, the lack of an optical transition layer for interfacial bonding significantly reduces the adhesion between the composite conductive layer and the substrate. During bending and high / low temperature impacts, interlayer peeling and conductive network breakage are very likely to occur, leading to a sharp drop in conductivity and failing to meet the requirements for long-term stable use in automotive scenarios.

[0084] Comparative Example 2: Conductive thin film without two-dimensional conductive nanosheets 1. Specific formula and process parameters Except for the embedded wide-temperature-range composite conductive layer 3, which does not contain two-dimensional conductive nanosheets, the other raw materials, formulation parameters, and preparation processes are completely consistent with those in Example 1. In order to keep the total solid content unchanged, the mass ratio of silver nanowires in the composite conductive layer is adjusted to 30%.

[0085] 2. Technical Effects This comparative example lacks two-dimensional conductive nanosheets, which cannot fill the gaps between the one-dimensional metal nanowires. This results in a significant increase in the contact resistance between the nanowires and a decrease in the overall conductivity of the film. At the same time, the limited number of overlap points between the one-dimensional nanowires makes them prone to separation during thermal expansion and contraction at high and low temperatures, leading to a significant increase in conductivity fluctuations over a wide temperature range. Furthermore, the lack of densification by two-dimensional nanosheets reduces the moisture barrier capacity of the composite conductive layer, making the silver nanowires susceptible to oxidation and corrosion, significantly reducing their weather resistance. The resistance increases significantly after bending, failing to meet the requirements for wide temperature range and long-term use in automotive applications.

[0086] Comparative Example 3: Conductive film using a single thermosetting process 1. Specific formula and process parameters Except for the composite conductive layer, which uses a single thermosetting process instead of a segmented thermosetting process, all other raw materials, formulation parameters, and preparation processes are completely consistent with those in Example 1. The single thermosetting process is direct curing at 125°C for 14 minutes.

[0087] 2. Technical Effects This comparative example did not employ segmented thermosetting, making it impossible to achieve a design where the three-dimensional conductive network is partially embedded and partially exposed. During the high-temperature rapid curing process, the solvent evaporates rapidly, leading to defects such as pinholes, cracks, and uneven thickness in the coating. Simultaneously, the conductive nanomaterials are completely encapsulated within the conductive polymer matrix, failing to form effective conductive pathways, resulting in a significant decrease in the film's conductivity. Furthermore, single-stage curing leads to uneven cross-linking of the conductive polymer matrix, insufficient interlayer adhesion, and issues such as coating damage and conductive network breakage during bending. The conductivity fluctuates significantly over a wide temperature range, failing to meet the requirements for flexible and wide-temperature-range applications in automotive applications.

[0088] III. Summary of Experimental Data and Verification Conclusions 1. Test Standard Description Visible light transmittance / haze: GB / T2410-2008, test wavelength 550nm; Surface resistance: Four-probe tester, GB / T3048.2-2007; Wide temperature range resistance fluctuation: -40℃ / 125℃ high and low temperature chambers were each kept at the temperature for 2 hours, and the change rate of surface resistance was tested; Bending performance: 1mm bending radius, resistance change rate after 100,000 bends; Weather resistance: Resistance change rate after 1000h of double 85 test (85℃, 85%RH); Water vapor transmission rate: GB / T26253-2010, test conditions 38℃, 90%RH.

[0089] 2. Summary table of experimental data Table 1:

[0090] Table 2:

[0091] 3. Verification Conclusion 1. All performance indicators of Examples 1-3 meet the requirements of this application and fully realize the technical effect of the design. They are excellent in optical performance, electrical conductivity stability, wide temperature range adaptability, bending performance and weather resistance, and are fully adapted to the use requirements of vehicle scenarios.

[0092] 2. Comparative Examples 1-3, having removed the main technical features of the solution in this application, all exhibited obvious performance defects and could not meet the usage requirements of vehicle-mounted scenarios, directly proving that the technical solution defined in this application is non-obvious and represents significant technical progress.

[0093] In summary, the automotive-grade wide-temperature-range flexible optical conductive thin film and its preparation method provided in this application have the following advantages: Working principle: This automotive-grade wide-temperature-range flexible optical conductive film employs a sequentially stacked structure consisting of a flexible transparent substrate 1, an optical matching transition layer 2, an embedded wide-temperature-range composite conductive layer 3, and a weather-resistant encapsulation protective layer 4. These structures work together to achieve stable optical, conductive, and weather-resistant performance. The specific working principle is as follows: The flexible transparent substrate 1 provides stable structural support for the overall film and has excellent optical performance and wide temperature range dimensional stability. It is not prone to thermal deformation or brittleness in alternating high and low temperature environments. It can provide a flat and uniform adhesion interface for the upper functional layer, while ensuring the overall flexibility and bendability of the film, adapting to the bonding needs of various curved and irregular structures in the vehicle.

[0094] An optical matching transition layer 2 is disposed between the flexible transparent substrate 1 and the embedded wide-temperature-range composite conductive layer 3. It employs an organic-inorganic hybrid structure with a continuously gradient refractive index. Along the direction from near the flexible transparent substrate 1 to near the embedded wide-temperature-range composite conductive layer 3, the refractive index gradually matches the refractive index parameters of the two adjacent layers, eliminating Fresnel reflection at the interlayer interface, reducing optical loss during light transmission, and ensuring the overall optical uniformity of the film. Simultaneously, the organic-inorganic hybrid structure can simultaneously improve the interfacial adhesion with the upper and lower layers, preventing interlayer delamination during long-term use or bending, and improving structural reliability. The mechanism by which the uniformly mixed organic-inorganic hybrid coating liquid achieves a continuously gradient refractive index is as follows: utilizing the surface energy differences and migration characteristics of different components in the coating liquid, combined with a stepwise curing process, to lock the gradient distribution. In the coating solution, the silane coupling agent-modified inorganic nanoparticles and refractive index modifier are high surface energy and high refractive index components, which will spontaneously accumulate towards the high surface energy substrate interface in the wet film state; the acrylate / fluorinated acrylate prepolymer is a low surface energy and low refractive index component, which will spontaneously migrate towards the low surface energy air interface in the wet film state; the component distribution on the substrate side is first locked by low energy ultraviolet pre-curing, and then the cross-linking and shaping of the entire film layer is completed by thermal curing, finally forming a stable structure with a continuous gradual change in refractive index along the film thickness direction.

[0095] The embedded wide-temperature-range composite conductive layer 3 serves as the conductive functional body of the thin film. It adopts a cross-linked conductive polymer matrix as the carrier, with one-dimensional metal nanowires and two-dimensional conductive nanosheets uniformly dispersed inside. The one-dimensional metal nanowires overlap to form a preliminary continuous conductive pathway, while the two-dimensional conductive nanosheets fill the gaps between the one-dimensional metal nanowires and the voids in the conductive network, reducing the contact resistance at the overlap points and improving the continuous conductive pathway. Together, they form an overlapping and interconnected three-dimensional conductive network. The cross-linked conductive polymer matrix adopts a double-doped modified cross-linked interpenetrating network structure, which can fix the spatial structure of the three-dimensional conductive network, suppress the thermal expansion and contraction of polymer molecular chains and dopant migration under high and low temperature environments, avoid overlap separation or structural deformation of the conductive network, and ensure the stability of the conductive performance of the thin film under wide temperature range. The three-dimensional conductive network is partially embedded inside the cross-linked conductive polymer matrix and partially exposed on the surface of the cross-linked conductive polymer matrix. It achieves structural fixation and anti-oxidation protection of the conductive network through the encapsulation of the polymer matrix, and ensures conductive contact efficiency through the exposed conductive structure on the surface, while further improving the interfacial bonding with the upper and lower functional layers.

[0096] The weather-resistant encapsulation protective layer 4 is disposed on the outside of the embedded wide-temperature-range composite conductive layer 3. It adopts a dense cross-linked fluorinated acrylate polymer structure, which can block external moisture, dust and corrosive substances from contacting the internal conductive layer and avoid oxidation and corrosion of the conductive material. The functional additives dispersed in the layer can absorb external ultraviolet rays, delay the aging and degradation of the polymer system, and extend the service life of the film. At the same time, it has excellent optical transmittance performance and will not cause additional optical loss to the light transmission of the film.

[0097] How to use: This automotive-grade wide-temperature-range flexible optical conductive film is suitable for various automotive optical conductive applications. Specific usage instructions are as follows: 1. Cutting and pretreatment: The film is cut according to the size and shape requirements of the vehicle application scenario. During the cutting process, the film surface is kept clean to avoid creases, damage and edge burrs. After cutting, the bonding surface of the film is cleaned with a dust-free cleaning process to remove dust, oil and impurities attached to the surface and ensure that the bonding interface is clean and flat.

[0098] 2. Bonding and Assembly: Based on the functional requirements of the application scenario, optical-grade pressure-sensitive adhesive is used to bond the film to the corresponding substrate surface. When used in automotive touch display modules, the side of the film with the flexible transparent substrate 1 is bonded to the upper surface of the display panel. The rolling process ensures that the film and the display panel are completely bonded without bubbles or curling edges. When used in automotive smart dimming windows, the film is bonded to the inner surface of the window glass to ensure that the embedded wide temperature range composite conductive layer 3 of the film forms a stable electrical connection with the driving electrode. When used in automotive curved interactive modules, the film is bent and bonded along with the curved structure to ensure that the film is not overstretched or damaged during the bending process.

[0099] 3. Circuit connection: The edge of the thin-film embedded wide temperature range composite conductive layer 3 is led out and connected to the electrode terminals of the vehicle control circuit by conductive adhesive or low temperature welding to form a stable electrical connection, ensuring the normal transmission of electrical signals. After the connection is completed, the connection part is insulated and encapsulated to avoid short circuits and leakage problems during use.

[0100] 4. Debugging and commissioning: After assembly and circuit connection are completed, the conductivity, optical performance and touch response performance of the film are debugged and calibrated. After confirming that the performance meets the requirements for vehicle use, it can be put into normal use. During use, the film can work stably for a long time in the normal high and low temperature, humidity and vibration environment of the vehicle, without the need for additional special maintenance.

[0101] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A vehicle-mounted wide-temperature-range flexible optical conductive film, characterized in that, It includes a flexible transparent substrate, an optical matching transition layer, an embedded wide-temperature-range composite conductive layer, and a weather-resistant encapsulation protective layer, which are stacked sequentially. The embedded wide-temperature-range composite conductive layer is a composite conductive system with a continuous interpenetrating network structure. The composite conductive system includes a cross-linked conductive polymer matrix, one-dimensional metal nanowires and two-dimensional conductive nanosheets uniformly dispersed in the cross-linked conductive polymer matrix. The one-dimensional metal nanowires and two-dimensional conductive nanosheets form an overlapping and interconnected three-dimensional conductive network in the cross-linked conductive polymer matrix. The three-dimensional conductive network is partially embedded inside the cross-linked conductive polymer matrix and partially exposed on the surface of the cross-linked conductive polymer matrix.

2. The automotive-grade wide-temperature-range flexible optical conductive film according to claim 1, characterized in that, The flexible transparent substrate is made of a wide temperature range optical grade polymer film with a thickness of 10 μm to 100 μm, a glass transition temperature of not less than 120°C, a light transmittance of not less than 92% in the visible light band, and a haze of not more than 0.5%.

3. The automotive-grade wide-temperature-range flexible optical conductive film according to claim 1, characterized in that, The optical matching transition layer is an organic-inorganic hybrid refractive index gradient layer. The refractive index of the optical matching transition layer is distributed along the direction from near the flexible transparent substrate to near the embedded wide temperature range composite conductive layer through the thickness gradient distribution of high refractive index inorganic components and low refractive index organic components. The thickness of the optical matching transition layer is 50nm to 200nm, and the light transmittance in the visible light band is not less than 98%.

4. The automotive-grade wide-temperature-range flexible optical conductive film according to claim 1, characterized in that, The cross-linked conductive polymer matrix is ​​a cross-linked interpenetrating network of poly(3,4-ethylenedioxythiophene) conductive polymer modified by dual doping. The dual doping modification is carried out by composite doping with sulfonic acid dopant and nonionic wide-temperature stabilizer. The mass ratio of sulfonic acid dopant to nonionic wide-temperature stabilizer is 5:1 to 10:

1. The conductivity of the cross-linked conductive polymer matrix is ​​not less than 100 S / cm, and the conductivity fluctuation range in the temperature range of -40℃ to 125℃ is not higher than 15%.

5. The automotive-grade wide-temperature-range flexible optical conductive film according to claim 1, characterized in that, The one-dimensional metal nanowire is a silver nanowire or a gold nanowire with a one-dimensional linear nanostructure. The aspect ratio of the one-dimensional metal nanowire is not less than 1000, the diameter is 15 nm to 30 nm, the length is 30 μm to 50 μm, and the mass percentage of the one-dimensional metal nanowire in the embedded wide temperature range composite conductive layer is 15% to 35%.

6. The automotive-grade wide-temperature-range flexible optical conductive film according to claim 1, characterized in that, The two-dimensional conductive nanosheet is a few-layer graphene nanosheet or MXene nanosheet with a two-dimensional planar sheet-like nanostructure. The diameter of the two-dimensional conductive nanosheet is 1 μm to 5 μm, the thickness is 1 nm to 5 nm, the ratio of the lateral dimension to the thickness is not less than 200, and the mass percentage of the two-dimensional conductive nanosheet in the embedded wide temperature range composite conductive layer is 2% to 8%.

7. The automotive-grade wide-temperature-range flexible optical conductive film according to claim 1, characterized in that, The weather-resistant encapsulation protective layer is a cross-linked fluorinated acrylate polymer layer. Ultraviolet absorbers and hindered phenolic antioxidants are dispersed within the weather-resistant encapsulation protective layer. The total mass percentage of the ultraviolet absorbers and hindered phenolic antioxidants is 0.5% to 3%. The thickness of the weather-resistant encapsulation protective layer is 1 μm to 5 μm. The light transmittance in the visible light band is not less than 90%, and the water vapor transmittance is not higher than 1 g / (m²). 2 •24h).

8. A method for preparing a vehicle-mounted wide-temperature-range flexible optical conductive thin film according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Pretreatment of flexible transparent substrate: The flexible transparent substrate is subjected to surface cleaning and plasma activation treatment to obtain the activated substrate; Step 2, Preparation of Optical Matching Transition Layer: An organic-inorganic hybrid coating liquid with a refractive index gradient and a surface energy differential design is coated on the activated substrate surface. After the wet film leveling completes the spontaneous gradient migration of components, it is pre-cured and thermally cured to lock the component gradient distribution in the film thickness direction, forming an optical matching transition layer with a refractive index that continuously varies from 1.50 to 1.62 from near the flexible transparent substrate to near the embedded wide temperature range composite conductive layer. Step 3: Preparation of embedded wide-temperature-range composite conductive layer: The cross-linked conductive polymer dispersion, one-dimensional metal nanowire dispersion, two-dimensional conductive nanosheet dispersion and cross-linking agent are mixed in proportion to obtain composite conductive coating liquid; the composite conductive coating liquid is coated on the surface of the optical matching transition layer and subjected to segmented thermosetting treatment to form embedded wide-temperature-range composite conductive layer. Step 4: Preparation of weather-resistant encapsulation protective layer: A fluorinated acrylate encapsulation coating liquid is coated on the surface of the embedded wide temperature range composite conductive layer, and then cured by ultraviolet light and heat to form a weather-resistant encapsulation protective layer, thus obtaining a vehicle-mounted wide temperature range flexible optical conductive film.

9. The method for preparing a vehicle-mounted wide-temperature-range flexible optical conductive thin film according to claim 8, characterized in that, In step three, the solid content of the composite conductive coating liquid is 3% to 8%, and the coating method is slot coating or micro-gravure coating. The segmented thermosetting treatment is as follows: pre-curing at 60°C to 70°C for 3 to 5 minutes, medium-temperature curing at 90°C to 110°C for 5 to 10 minutes, and high-temperature curing at 120°C to 130°C for 2 to 5 minutes.

10. The method for preparing a vehicle-mounted wide-temperature-range flexible optical conductive thin film according to claim 8, characterized in that, In step two, the organic-inorganic hybrid coating liquid is prepared by mixing silane coupling agent-modified nano-silica sol, acrylate prepolymer, refractive index modifier, and photoinitiator in a certain proportion. The solid content of the coating liquid is 2% to 5%. The pre-curing treatment uses low-energy ultraviolet light pre-curing with a curing energy of 300 mJ / cm². 2 Up to 500mJ / cm 2 The component gradient distribution on the substrate side is locked in; the temperature of the thermosetting treatment is 100℃ to 120℃ and the time is 5min to 10min, which is used to complete the cross-linking and shaping of the entire film layer and form a stable refractive index continuously gradient structure.

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