Dimming film integrated with heating function and preparation method thereof

Abstract

The invention relates to a dimming film integrated with a heating function and a preparation method of the dimming film. A first transparent single-face conductive film, an electrochromic layer, a second transparent double-face conductive film, an electric heating layer and a third transparent single-face conductive film are sequentially stacked in the thickness direction. The first transparent single-sided conductive film is provided with a first conductive layer, the second transparent double-sided conductive film is provided with a second conductive layer and a third conductive layer which are relatively parallel, and the third transparent single-sided conductive film is provided with a fourth conductive layer; the second conductive layer and the first conductive layer form an electrochromic electric field, and the third conductive layer and the fourth conductive layer form an electro-heating electric field; the electrochromic layer realizes light transmittance adjustment by means of molecule / particle deflection under the action of an electrochemical color change reaction or an electric field, and the electric heating layer generates heat through dielectric loss of a polar solvent. According to the scheme, independent / cooperative operation of the dimming function and the heating function is achieved, the energy utilization rate is high, the low-temperature heating effect is stable, interlayer interference is avoided, the light transmission is good, the structure is stable, and the problems that a traditional color-changing dimming product is high in energy consumption, the heating temperature control function cannot be effectively integrated with the dimming function layer, and low-temperature adaptation is poor are solved.

Description

Technical Field

[0001] This invention belongs to the field of dimming film technology, and particularly relates to a dimming film with integrated heating function and its preparation method. Background Technology

[0002] With the widespread adoption of new energy vehicles, more and more passenger cars are adopting panoramic sunroofs as their roofs. The application of panoramic sunroofs in automobiles not only reflects the technological attributes of new energy vehicles but also meets the requirements for lightweight construction. More importantly, the use of panoramic sunroofs can free up more space in the chassis of new energy vehicles to install larger power batteries, while effectively meeting the headroom needs of passengers. However, the widespread use of panoramic sunroofs has brought a new problem to the industry: the phenomenon of passengers' heads getting hot and needing to use umbrellas while sitting in the car. Naturally, dimming technology with transmittance adjustment capabilities has been applied to panoramic sunroofs.

[0003] Currently, mainstream dimming technologies include polymer-dispersed liquid crystal (PDLC), organic electrochromic (organic EC), suspended particle devices (SPD), and dye-based liquid crystal (DLC). Without exception, all of these technologies experience functional degradation or even become unusable at low temperatures. Therefore, effectively overcoming the problem of poor dimming glass performance at low temperatures is essential. Current dimming films integrating heating functions can be broadly categorized into two main technologies: resistive heating (such as ITO films and silver nanowire films) and non-resistive heating (such as electromagnetic induction and infrared radiation). However, all of these technologies have significant and insurmountable shortcomings. Resistance heating has high energy consumption, with an energy utilization rate of ≤70%, and a large difference in the coefficient of thermal expansion between the heating layer and the dimming layer, with a difference of ≥5×10. -6 / ℃, during long-term use, thermal stress accumulation can easily lead to interlayer delamination failure; electromagnetic induction heating requires a high-frequency alternating power supply of 10-50kHz, which not only increases the complexity of the equipment but also easily generates electromagnetic interference. At the same time, the uneven dispersion of soft magnetic alloy particles can also lead to local heating differences in the film, affecting the heating uniformity; infrared radiation heating relies on ceramic powder to achieve infrared excitation. In medium and low temperature environments <-15℃, the excitation efficiency will decrease by more than 30%, resulting in a significant slowdown in de-icing and anti-fogging speeds, making it difficult to meet the needs of use in extreme environments.

[0004] Therefore, given the numerous problems existing in current dimming films with integrated heating functions, such as high energy consumption, uneven heating, and insufficient low-temperature adaptability, it is essential to develop a new type of dimming film with integrated heating functions. Summary of the Invention

[0005] The purpose of this application is to solve the technical problems of current dimming films with integrated heating functions, such as high energy consumption, uneven heating, and insufficient low-temperature adaptability, and to provide a dimming film with integrated heating functions.

[0006] To achieve the above objectives, this application provides a dimming film with integrated heating function, comprising, along its thickness direction, a first transparent single-sided conductive film, an electrochromic layer, a second transparent double-sided conductive film, an electrothermal layer, and a third transparent single-sided conductive film, stacked sequentially; the first transparent single-sided conductive film has a first conductive layer, the second transparent double-sided conductive film has a second conductive layer and a third conductive layer arranged in parallel, and the third transparent single-sided conductive film has a fourth conductive layer; wherein: The second conductive layer is disposed adjacent to the electrochromic layer, the third conductive layer is disposed adjacent to the electrothermal layer, and the second conductive layer and the first conductive layer are arranged opposite to each other to form an electrochromic electric field, and the third conductive layer and the fourth conductive layer are arranged opposite to each other to form an electrothermal electric field. The electrochromic layer undergoes an electrochemical color-changing reaction under the action of the electrochromic electric field, or the light transmittance is adjusted by the deflection of molecules / particles under the action of the electric field; the electrothermal layer includes a polar solvent, a main resin, a diluent monomer and a photocuring initiator, and the polar solvent generates heat by dielectric loss under the action of the electrothermal electric field.

[0007] Based on the above technical solution, the working principle of the dimming film with integrated heating function is as follows: the first conductive layer, the second conductive layer, the third conductive layer and the fourth conductive layer are electrically connected to the driving module respectively. The driving module can output electric field parameters (including voltage amplitude, frequency, waveform, etc.) that are adapted to the electrochromic reaction and dielectric loss heating according to actual usage requirements, so as to realize the independent control and coordinated operation of the two functional layers.

[0008] When the driving module is started, it outputs an electric field with adapted parameters (usually a low-to-medium frequency alternating electric field or a DC electric field) to the electrochromic electric field formed by the second conductive layer and the first conductive layer. When this electric field acts on the electrochromic layer, the electrochromic material in the driving layer undergoes a redox electrochemical color-changing reaction. By changing the distribution of electronic energy levels or molecular configuration or molecular / particle deflection inside the material, the absorption, reflection or transmission characteristics of visible light are adjusted, thereby precisely realizing the continuous and adjustable light transmittance (such as gradient switching from the transparent state to the light-blocking state).

[0009] Simultaneously, the drive module outputs a mid-frequency alternating electric field adapted to dielectric loss to the electrothermal electric field formed by the third and fourth conductive layers. This alternating electric field causes the polar solvent molecules in the electrothermal layer to undergo high-frequency periodic turning, polarization, and frictional collisions along the direction of the electric field. Through the dielectric loss effect, electrical energy is efficiently converted into heat energy, and the heat is evenly diffused to the entire membrane through thermal conduction, thereby achieving anti-fogging, de-icing, or temperature control functions.

[0010] Because the second transparent double-sided conductive film achieves physical isolation and independent operation of the two electric fields through the double conductive layer design, and the driving module can adjust the parameters of the two electric fields as needed (such as starting the dimming function separately, starting the heating function separately, or starting both simultaneously), the electrochromic layer and the electrothermal layer do not interfere with each other during operation. This ensures both the accuracy of transmittance adjustment and the efficient and stable heating effect, ultimately achieving synergistic adaptation of dimming and heating functions to meet the needs of various scenarios.

[0011] As a further improvement to this application, the electrothermal layer comprises the following components by weight percentage: Polar solvents 44%–45%; Main resin 45%–48%; Dilute monomers by 5%–8%; Photocuring initiator 1%–3%; Wherein: the polar solvent is selected from at least one of ethylene glycol derivatives, propylene glycol derivatives, N-octylpyrrolidone, N-methylpyrrolidone, methanol, ethanol, glycerol, dimethyl sulfoxide, acetone, ethyl acetate, tetrahydrofuran, dimethylformamide, dimethylacetamide, pyridine, methyl isobutyl ketone, cyclohexanone, 1,3-propanediol, diethylene glycol dimethyl ether, formamide, ethanolamine, ethyl lactate, glycerol formaldehyde, 2-methyltetrahydrofuran, sulfolane, N-cyclohexylpyrrolidone, triethylene glycol, ethylene glycol monomethyl ether, propylene glycol monopropyl ether, electronic grade N-methylpyrrolidone, electronic grade dimethylacetamide, electronic grade propylene glycol methyl ether acetate, polyethylene glycol 400, propylene glycol, etc. The main resin is polyurethane acrylic resin; The diluent monomers are selected from 1,6-hexanediol diacrylate, isoborneol acrylate, isoborneol methacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, lauryl acrylate, lauryl methacrylate, ethoxylated phthalate diacrylate, dipropylene glycol diacrylate, tetrahydrofuran acrylate, neopentyl glycol diacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, ethoxylated ethoxylated acrylate, 2-phenoxyethyl acrylate, isotridecyl acrylate, hydroxyethyl methacrylate, 1,4-butanediol diacrylate, tricyclodecanediethanol diacrylate, ethylene glycol dimethacrylate, bis(trimethylolpropane)tetraacrylate, propoxylated glycerol triacrylate, tri... At least one of the following: (2-hydroxyethyl) isocyanurate triacrylate, dicyclopentenylethoxymethacrylate, acrylmorpholine, hydroxypropyl methacrylate, cyclotrimethylolpropane methyl acetal acrylate, o-phenylphenoxyethyl acrylate, ethoxylated bisphenol A dimethacrylate, 2-hydroxyethyl methacrylate phosphate, glycidyl methacrylate, N-vinylpyrrolidone, β-carboxyethyl acrylate, methoxylated polyethylene glycol monomethacrylate, polyethylene glycol (400) diacrylate, ethoxylated bisphenol A diacrylate, 3,3,5-trimethylcyclohexyl acrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated bisphenol A dimethacrylate, methacrylamide ethyl ethylene urea, alkyl oxyphenol acrylate, etc. The photocuring initiator is selected from 2-hydroxy-2-methylpropionylbenzene (1173), 1-hydroxycyclohexylphenyl ketone (184), 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoyl phenylphosphonate (TPO-L), 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone (907), 2-benzyl-2-(dimethylamino)-1-(4-morpholinylphenyl)-1-butanone (369), benzophenone (BDK), 2,2-dimethoxy-2-phenylacetophenone (651), phenylbis(2,4,6-trimethylbenzoyl) At least one of the following: acylphosphine oxide (819), 2-hydroxy-2-methyl-1-phenyl-1-propanone (MBF), benzophenone (BP), 2-isopropylthioxanthanone (ITX), 2,4,6-trimethylbenzophenone (2,4,6-trimethylbenzophenone), 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone (2959), 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]-1-propanone oligomer (659), 4-chlorobenzophenone (CTX), 2,4-diethylthioxanthanone (DETX), 4-methylbenzophenone (MK).

[0012] Based on the above technical solution, the components forming the electrothermal layer ensure molding reliability through functional synergy: the polar solvent possesses both high dielectric constant and good compatibility, enabling it to form a uniform dispersion system with the main resin and diluent monomers, while its low volatility and chemical stability prevent delamination or volatilization defects during preparation; the main resin is a polyurethane acrylic resin, whose acrylate double bonds can crosslink and polymerize with the diluent monomers to form a three-dimensional network structure with excellent film-forming properties, mechanical strength, and interlayer adhesion, providing a stable fixation carrier for the polar solvent; the diluent monomer is trimethylolpropane triacrylate. (TMPTA), isobornyl acrylate (IBOA), etc., reduce the viscosity of the system through mono / polyfunctional synergy to adapt to the film-forming process, while adjusting the crosslinking density to ensure that the cured layer has both density and flexibility; the photocuring initiator can efficiently decompose to generate free radicals under ultraviolet light irradiation, initiating rapid crosslinking and polymerization of the main resin and diluent monomers, achieving rapid curing at room temperature with low residue and no impact on the layer performance. The above components are precisely proportioned by mass ratios of 44%–45%, 45%–48%, 5%–8%, and 1%–3% to ultimately form a stable structure in which the resin network encapsulates the polar solvent.

[0013] Before power-on, the visible light transmittance of each raw material is ≥98%, and the refractive index matching degree is high (difference ≤0.02). The three-dimensional cross-linked network formed after photocuring is uniform and dense, without pores, particle agglomeration or phase separation. There is no additional absorption or scattering loss when light passes through. After power-on, the electrothermal layer relies on the dielectric loss of the polar solvent to generate heat. The alternating electric field only causes the polar solvent molecules to undergo high-frequency turning, polarization and frictional movement (molecular-level movement does not change the molecular structure and optical properties). Moreover, the main resin and polar solvent have excellent thermal stability. There is no thermal decomposition, discoloration or phase separation at the normal working temperature (≤80℃). The refractive index still remains matched. In addition, there is no need to add light-shielding components such as metal conductive particles. Therefore, the transmittance can be maintained at ≥70% before and after power-on, ensuring that the overall optical performance of the dimming film is not affected.

[0014] As a further improvement of this application, the thickness of the first transparent single-sided conductive film is 50μm to 250μm, the tensile strength is ≥78MPa, Ra is 0.2μm, the light transmittance is 80 to 93%, and the sheet resistance is 2 to 500Ω / □; the thickness of the second transparent double-sided conductive film is 50μm to 250μm, the tensile strength is ≥78MPa, Ra is 0.2μm, the light transmittance is 80 to 93%, and the sheet resistance is 2 to 500Ω / □; the thickness of the third transparent single-sided conductive film is 50μm to 250μm, the tensile strength is ≥78MPa, Ra is 0.2μm, the light transmittance is 80 to 93%, and the sheet resistance is 2 to 500Ω / □.

[0015] As a further improvement of this application, the electrochromic layer includes a dimming material, which is selected from at least one of liquid crystal dimming materials, electrochromic dimming materials, suspended particle dimming materials, and metal sulfide nanoparticle dimming materials with anisotropic color-changing function.

[0016] As a further improvement of this application, the thickness of the electrochromic layer is 10 μm to 300 μm; the thickness of the electrothermal layer is 5 μm to 100 μm.

[0017] To achieve the above objectives, this application also provides a method for preparing the dimming film with integrated heating function described above, comprising the following steps: S1. Preparation of electrochromic coating solution; S2. Preparation of electrothermal coating solution: Add polar solvent, main resin, diluent monomer and photocuring initiator into a container according to the preset content, stir and mix thoroughly to obtain electrothermal coating solution; S3. Place the electrochromic coating liquid between the first transparent single-sided conductive film and the second transparent double-sided conductive film to form an electrochromic structure; S4. Apply an electrothermal coating liquid to the side of the second transparent double-sided conductive film away from the electrochromic coating layer to form an electrothermal coating layer. Attach a third transparent single-sided conductive film with its conductive surface adjacent to the electrothermal coating layer. Cure under ultraviolet light to obtain a dimming film with integrated heating function.

[0018] As a further improvement of this application, when the dimming material is a liquid crystal dimming material, the preparation steps of the electrochromic coating solution are as follows: 43%–47% liquid crystal molecules, 39%–43% Sartoma 8888 polyurethane acrylic resin, 9%–11% isobornyl acrylate (IBOA) monomer, and 1%–3% (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide TPO) photoinitiator are added to the reaction vessel by mass percentage; the mixture is stirred thoroughly to obtain the electrochromic coating solution. The preparation steps of the electrochromic structure are as follows: An electrochromic coating solution is coated onto the surface of the first conductive layer of a first transparent single-sided conductive film, forming an electrochromic coating layer with a thickness of 50 μm to 100 μm. The third conductive layer of a second transparent double-sided conductive film is then attached to the electrochromic coating layer. Ultraviolet curing is performed to obtain the electrochromic structure. Preferably, during ultraviolet curing, the wavelength of the ultraviolet light is 365 nm and the power is 75 mW / cm². 2 The curing time is 40 seconds.

[0019] As a further improvement of this application, when the light-adjusting material is nano-copper sulfide (one of the metal sulfides with anisotropic color-changing function), the preparation steps of the electrochromic coating solution are as follows: 38%–42% nano-copper sulfide dispersion, 36%–40% Sartoma 8888 polyurethane acrylic resin, 8%–12% isobornyl acrylate (IBOA) monomer, and 1%–3% (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide TPO) photoinitiator are added to the reaction vessel by mass percentage; the mixture is stirred thoroughly to obtain the electrochromic coating solution. The preparation steps of the electrochromic structure are as follows: An electrochromic coating solution is coated onto the surface of the first conductive layer of a first transparent single-sided conductive film, forming an electrochromic coating layer with a thickness of 50 μm to 100 μm. The third conductive layer of a second transparent double-sided conductive film is then attached to the electrochromic coating layer. Ultraviolet curing is performed to obtain the electrochromic structure. Preferably, during ultraviolet curing, the wavelength of the ultraviolet light is 365 nm and the power is 75 mW / cm². 2 The curing time is 40 seconds.

[0020] The specific benefits of this application are as follows: This application provides a dimming film with integrated heating function, comprising a first transparent single-sided conductive film, an electrochromic layer, a second transparent double-sided conductive film, an electrothermal layer, and a third transparent single-sided conductive film stacked sequentially along the thickness direction; the first transparent single-sided conductive film has a first conductive layer, the second transparent double-sided conductive film has relatively parallel second and third conductive layers, and the third transparent single-sided conductive film has a fourth conductive layer; the second conductive layer is adjacent to the electrochromic layer, and the third conductive layer is adjacent to the electrothermal layer, the second and first conductive layers forming an electrochromic electric field, and the third and fourth conductive layers forming an electrothermal electric field; the electrochromic layer undergoes an electrochemical color-changing reaction under the action of the electric field to adjust the light transmittance, and the electrothermal layer contains components such as polar solvents, generating heat through the dielectric loss of the polar solvents.

[0021] Employing a dual-electric-field independent design, the electric fields are physically isolated through a second transparent double-sided conductive film, ensuring that dimming and heating functions do not interfere with each other. The electrochromic area and the electrothermal area are controlled by separate electric fields. The electrothermal layer relies on dielectric loss for heating, resulting in energy utilization far exceeding that of traditional resistance heating and lower energy consumption. Heating efficiency does not decrease in low-temperature environments, solving the problem of insufficient low-temperature adaptability of traditional infrared radiation heating. Each film layer has excellent light transmittance, maintaining high transmittance before and after power-on, without affecting the user experience. The interlayer structure is rationally designed with a high degree of matching thermal expansion coefficients, reducing the risk of interlayer delamination, improving product stability, and meeting the needs of multiple application scenarios. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them, and are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0023] Example 1 This embodiment provides a dimming film with integrated heating function, comprising a first transparent single-sided conductive film, an electrochromic layer, a second transparent double-sided conductive film, an electrothermal layer, and a third transparent single-sided conductive film stacked sequentially along the thickness direction; the first transparent single-sided conductive film has a first conductive layer, the second transparent double-sided conductive film has a second conductive layer and a third conductive layer that are relatively parallel to each other, and the third transparent single-sided conductive film has a fourth conductive layer; wherein: The second conductive layer is disposed adjacent to the electrochromic layer, the third conductive layer is disposed adjacent to the electrothermal layer, and the second conductive layer and the first conductive layer are arranged opposite to each other to form an electrochromic electric field, and the third conductive layer and the fourth conductive layer are arranged opposite to each other to form an electrothermal electric field. The electrochromic layer undergoes an electrochemical color-changing reaction under the action of the electrochromic electric field, or the molecules / particles under the action of the electric field are deflected to achieve light transmittance adjustment; the electrothermal layer includes a polar solvent, a main resin, a diluent monomer and a photocuring initiator, and under the action of the electrothermal electric field, the polar solvent generates heat through dielectric loss.

[0024] This embodiment also provides a method for preparing a dimming film with integrated heating function, which is completed by the following steps: S1. Preparation of electrochromic coating solution: 45% liquid crystal molecules, 43% Sartoma 8888 polyurethane acrylate resin, 10% isobornyl acrylate (IBOA) monomer, and 2% (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide TPO) photoinitiator are added to the reaction vessel by mass percentage; the mixture is stirred thoroughly to obtain the electrochromic coating solution. S2. Preparation of electrothermal coating solution: By mass percentage, 45% N-methylpyrrolidone, 45% Sartoma 8888 polyurethane acrylate resin, 5% trimethylolpropane triacrylate (TMPTA monomer), 3% isobornyl acrylate (IBOA) monomer, and 2% (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide TPO) photoinitiator are added to the reaction vessel and stirred thoroughly to obtain the electrothermal coating solution; S3. Apply the electrochromic coating solution to the surface of the first conductive layer of the first transparent single-sided conductive film, forming an electrochromic coating layer with a thickness of 50μm to 100μm. Attach the third conductive layer of the second transparent double-sided conductive film onto the electrochromic coating layer. Cure under ultraviolet light with a wavelength of 365nm and a power of 75mW / cm². 2 The curing time is 40 seconds, resulting in an electrochromic structure; S4. Apply an electrothermal coating liquid to the side of the second transparent double-sided conductive film away from the electrochromic coating layer to form an electrothermal coating layer. Then, attach a third transparent single-sided conductive film, with the conductive surface of the third transparent single-sided conductive film adjacent to the electrothermal coating layer. Cure under ultraviolet light (UV) with a wavelength of 365 nm and a power of 75 mW / cm². 2 The curing time is 40 seconds, resulting in a dimming film with integrated heating function.

[0025] Example 2 The difference between this embodiment and Embodiment 1 lies in the preparation method of the dimming film with integrated heating function. It is prepared by the following steps: S1. Preparation of electrochromic coating solution: 40% nano copper sulfide dispersion, 38% Sartoma 8888 polyurethane acrylic resin, 10% isobornyl acrylate (IBOA) monomer, and 2% (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide TPO) photoinitiator are added to the reaction vessel by mass percentage; the mixture is stirred thoroughly to obtain the electrochromic coating solution. S2. Preparation of electrothermal coating solution: By mass percentage, 45% N-methylpyrrolidone, 45% Sartoma 8888 polyurethane acrylate resin, 5% trimethylolpropane triacrylate (TMPTA monomer), 3% isobornyl acrylate (IBOA) monomer, and 2% (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide TPO) photoinitiator are added to the reaction vessel and stirred thoroughly to obtain the electrothermal coating solution; S3. Apply the electrochromic coating solution to the surface of the first conductive layer of the first transparent single-sided conductive film, forming an electrochromic coating layer with a thickness of 50μm to 100μm. Attach the third conductive layer of the second transparent double-sided conductive film onto the electrochromic coating layer. Cure under ultraviolet light with a wavelength of 365nm and a power of 75mW / cm². 2 The curing time is 40 seconds, resulting in an electrochromic structure; S4. Apply an electrothermal coating liquid to the side of the second transparent double-sided conductive film away from the electrochromic coating layer to form an electrothermal coating layer. Then, attach a third transparent single-sided conductive film, with the conductive surface of the third transparent single-sided conductive film adjacent to the electrothermal coating layer. Cure under ultraviolet light (UV) with a wavelength of 365 nm and a power of 75 mW / cm². 2The curing time is 40 seconds, resulting in a dimming film with integrated heating function.

[0026] Comparative Example 1 The difference between this comparative example and Example 1 is that it provides a dimming film without integrated heating function. A first transparent single-sided conductive film, an electrochromic layer, and a second transparent double-sided conductive film are stacked sequentially along the thickness direction. The first transparent single-sided conductive film has a first conductive layer, and the second transparent double-sided conductive film has a second conductive layer and a third conductive layer that are relatively parallel to each other. The second conductive layer and the first conductive layer are arranged opposite to each other to form an electrochromic electric field. The electrochromic layer undergoes an electrochemical color-changing reaction under the action of the electrochromic electric field to achieve light transmittance adjustment.

[0027] This embodiment also provides a method for preparing a dimming film without integrated heating function, which is completed by the following steps: S1. Preparation of electrochromic coating solution: 45% liquid crystal molecules, 43% Sartoma 8888 polyurethane acrylate resin, 10% isobornyl acrylate (IBOA) monomer, and 2% (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide TPO) photoinitiator are added to the reaction vessel by mass percentage; the mixture is stirred thoroughly to obtain the electrochromic coating solution. S3. Apply the electrochromic coating solution to the surface of the first conductive layer of the first transparent single-sided conductive film, forming an electrochromic coating layer with a thickness of 50μm to 100μm. Attach the third conductive layer of the second transparent double-sided conductive film onto the electrochromic coating layer. Cure under ultraviolet light with a wavelength of 365nm and a power of 75mW / cm². 2 The curing time is 40 seconds, resulting in a dimming film without integrated heating function.

[0028] Comparative Example 2 Commercially available traditional resistive heating dimming films, such as Kheat™ PI resistive heating film.

[0029] Comparative Example 3 Commercially available traditional infrared integrated heating and dimming films, such as: Xianfeng Nano XFQ025.

[0030] The dimming films of Examples 1-2 and Comparative Examples 1-3 were subjected to performance tests. The test standards or test procedures for each performance are as follows: 1. Transmission rate The transmittance test was performed according to GB / T 2410-2008 "Determination of transmittance and haze of transparent plastics". Before the test, the dimming film samples prepared in the examples and comparative examples were cut into 100mm×100mm squares to ensure that the sample surface was free of scratches, stains, bubbles and other defects. They were placed in a standard environment of 23℃±2℃ and 50%±5% relative humidity for 24 hours for conditioning. The test was conducted using a method conforming to ISO 13468-1. The required dual-beam spectrophotometer is set to a test wavelength range of 380nm–780nm (visible light band). Air is used as a reference blank sample. The instrument is first calibrated for zero point and baseline correction. During testing, the sample is fixed flat on the sample holder, ensuring that the sample is perpendicular to the optical path and without deviation. The average transmittance of the sample across the entire wavelength band is measured in the unpowered state (initial transparent state) and in the powered and dimmed state to the maximum light-blocking state. The transmittance change data during the power-on heating process (maintaining the normal operating temperature ≤80℃) is recorded. Five test points are selected at different positions for each sample, and the arithmetic mean is taken as the final transmittance result. The transmittance data before and after power-on (heated or dimmed state) must be accurate to 0.1%, and the ambient temperature and humidity during the test process must be recorded simultaneously to ensure the accuracy and repeatability of the test results.

[0031] 2. Heating efficiency First, prepare the integrated heating dimming film samples prepared in Examples 1-2 (cut to 150mm×150mm, ensuring the conductive layer leads are intact) and the dimming film without integrated heating function in the comparative example (as a blank control). At the same time, prepare a traditional resistive heating dimming film (commercially available, of the same size, as a performance comparison sample). Build a low-temperature environment test chamber equipped with a temperature control system (accuracy ±0.5℃), a humidity control module (maintaining relative humidity 40%±5%), a high-definition camera (25fps frame rate, used to record the ice-breaking process), and a power meter (accuracy ±0.1W, used to monitor heating energy consumption). Secondly, before the experiment, all samples were placed at room temperature (23℃±2℃) for 12 hours to ensure that the initial state was consistent. Then, deionized water was evenly sprayed on the test surface of each sample (the side away from the conductive lead), and the water film thickness was controlled to be 1.5mm±0.2mm. The samples were then placed in a low-temperature environment test chamber, and the cooling program was started to reduce the temperature inside the chamber to the preset temperature (-10℃, -18℃, -25℃) at a rate of 5℃ / min and held at that temperature for 3 hours to ensure that the water film was completely frozen to form a uniform ice layer (the ice layer thickness was confirmed by a laser thickness gauge and should reach 1.2mm±0.1mm). Subsequently, the first, second, third, and fourth conductive layers of the sample from the embodiment were electrically connected to the common drive module. The traditional resistance heating sample was connected to its dedicated drive power supply, all set to the rated operating voltage (determined according to sample specifications to ensure stable heating power). At the same time, the power meter was started to record energy consumption data, and the high-definition camera began to record the ice-breaking process. Every 30 seconds, the remaining thickness of the ice layer was measured by a laser thickness gauge until the ice layer completely melted (judgment criteria: no visible ice layer on the sample test surface, water film completely detached or in liquid flow). The total time from the start of heating to the complete melting of the ice layer was recorded. Each sample was tested three times, and the average ice-breaking time and the average energy consumption were taken as the final result. The blank control sample was placed in a -25℃ environment for the same time without heating, and the changes in the state of the ice layer were observed. During the experiment, the temperature inside the cryogenic chamber needed to be monitored in real time to avoid temperature fluctuations exceeding ±1℃. After each test, the sample test surface needed to be cleaned to ensure that no residual ice layer or water stains would affect the next test.

[0032] The test results are shown in Table 1.

[0033] Table 1

[0034] As shown in Table 1, comparing Comparative Example 1 with Examples 1 and 2, all three have the same initial light-blocking performance of 15%. However, Examples 1 and 2 have an additional high-efficiency heating function, while Comparative Example 1 has no heating capability and cannot meet the requirements for de-icing and anti-fogging in low-temperature environments. In terms of light transmittance, Examples 1 and 2 have a maximum transparent transmittance of 70% and 72% respectively, which is slightly lower than the 80% of Comparative Example 1, but still meets the optical requirements for practical use. Moreover, through functional integration, Examples 1 and 2 compensate for the limitations of simple dimming films in various scenarios and solve the technical problem of traditional dimming films lacking heating adaptation.

[0035] Comparing Comparative Example 2 with Examples 1 and 2, it can be seen that Examples 1 and 2 have significant advantages in heating efficiency and energy consumption control: in the range of -10℃ to -25℃, the ice-breaking time is shortened by 1-2 seconds compared with Comparative Example 2, and the energy consumption is only 50%-75% of that of Comparative Example 2; the coefficient of thermal expansion (24×10) -6 / ℃-25×10 -6 (°C) is much lower than 46 × 10⁻⁶ in Comparative Example 2. -6 / ℃, significantly reducing the risk of interlayer delamination. In terms of light transmittance, the maximum transparent transmittance of the embodiment (70%-72%) is slightly better than that of Comparative Example 2 (68%), achieving the synergistic advantages of efficient heating, low energy consumption, high stability, and superior optics.

[0036] Comparing Comparative Example 3 with Examples 1 and 2, it can be seen that the ice-breaking time of the three is similar, but the energy consumption is reduced by 10%-45%, and the maximum transparent state transmittance (70%-72%) far exceeds that of Comparative Example 3 (50%). This is because: the electrothermal layer uses polar solvent dielectric loss heating, which has a higher energy utilization rate; the second transparent double-sided conductive film realizes dual electric field isolation to avoid functional interference; the refractive index matching degree of each component is high, there are no light-blocking components, and the light transmittance is excellent; the interlayer thermal expansion coefficient matching is good, the structural stability is stronger, and the problems of low-temperature efficiency decay and poor light transmittance of traditional infrared heating are solved.

[0037] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0038] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A light control film integrated with a heating function, characterized by, A first transparent single-side conductive film, an electrochromic layer, a second transparent double-side conductive film, an electrocaloric layer and a third transparent single-side conductive film are sequentially stacked in the thickness direction; the first transparent single-side conductive film is provided with a first conductive layer, the second transparent double-side conductive film is provided with a second conductive layer and a third conductive layer which are relatively parallel, and the third transparent single-side conductive film is provided with a fourth conductive layer; wherein: The second conductive layer is arranged immediately adjacent to the electrochromic layer, the third conductive layer is arranged immediately adjacent to the electrocaloric layer, and the second conductive layer and the first conductive layer are arranged oppositely to form an electrochromic electric field, and the third conductive layer and the fourth conductive layer are arranged oppositely to form an electrocaloric electric field; The electrochromic layer undergoes an electrochemical color reaction under the action of the electrochromic electric field or a molecular / particle deflection under the action of the electric field to realize light transmittance adjustment; the electrocaloric layer includes a polar solvent, a main resin, a dilution monomer and a photocuring initiator, and under the action of the electrocaloric electric field, the polar solvent undergoes dielectric loss to generate heat.

2. The integrated heating function dimming film according to claim 1, wherein, The electrocaloric layer includes the following components in mass percentage: The polar solvent is selected from at least one of ethylene glycol derivatives, propylene glycol derivatives, N-octyl pyrrolidone, N-methyl pyrrolidone, laurocapram, N-ethyl pyrrolidone, methanol, ethanol, glycerol, dimethyl sulfoxide, acetone, ethyl acetate, tetrahydrofuran, dimethyl formamide, dimethyl acetamide, pyridine, methyl isobutyl ketone, cyclohexanone, 1,3-propanediol, diethylene glycol dimethyl ether, formamide, ethanolamine, ethyl lactate, glycerol formaldehyde, 2-methyl tetrahydrofuran, cyclobutane sulfone, N-cyclohexyl pyrrolidone, triethylene glycol, ethylene glycol monomethyl ether, propylene glycol monopropyl ether, electronic grade N-methyl pyrrolidone, electronic grade dimethyl acetamide, electronic grade propylene glycol methyl ether acetate, polyethylene glycol 400, and propylene glycol. The main resin is a polyurethane acrylic resin. The main resin is a polyurethane acrylic resin. ​ 3. The integrated heating function dimming film according to claim 1, wherein, ​ 4. The integrated heating function dimming film according to claim 1, wherein, ​ 5. The integrated heating function dimming film according to claim 1, wherein, The dilution monomer is at least one selected from 1,6-hexanediol diacrylate, isobornyl acrylate, isobornyl methacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, lauryl acrylate, lauryl methacrylate, ethoxylated phthalic acid diacrylate, tripropyleneglycol diacrylate, tetrahydrofurfuryl acrylate, neopentyl glycol diacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, ethoxylated ethoxy acrylate, 2-phenoxyethyl acrylate, isotridecyl acrylate, hydroxyethyl methacrylate, 1,4-butanediol diacrylate, tricyclodecane dimethanol diacrylate, ethylene glycol dimethacrylate, ditrimethylolpropane tetraacrylate, glyceryl triacrylate propoxylate, tris(2-hydroxyethyl) isocyanurate triacrylate, dicyclopentenyl ethoxy methyl methacrylate, acryloyl morpholine, hydroxypropyl methacrylate, cyclotrimethylolpropane formal acrylate, o-phenylphenoxyethyl acrylate, ethoxylated bisphenol A dimethacrylate, 2-hydroxyethyl methacrylate phosphate, glycidyl methacrylate, N-vinyl pyrrolidone, beta-carboxyethyl acrylate, methoxy polyethylene glycol monomethacrylate, polyethylene glycol (400) diacrylate, ethoxylated bisphenol A diacrylate, 3,3,5-trimethylcyclohexyl acrylate, ethoxylated trimethylolpropane triacrylate, ethoxylated bisphenol A dimethacrylate, methacrylamidoethyl ethylene urea, alkoxylated phenol acrylate.

6. The integrated heating function dimming film according to claim 1, wherein, The photo-curing initiator is at least one selected from 1173, 184, TPO, TPO-L, 907, 369, BDK, 651, 819, MBF, BP, ITX, 2,4,6-trimethyl benzophenone, 2959, 659, CTX, DETX, MK.

7. The integrated heating function dimming film according to claim 1, wherein, The first transparent single-side conductive film has a thickness of 50-250 μm, a tensile strength of ≥78 MPa, a Ra of 0.2 μm, a light transmittance of 80-93%, and a square resistance of 2-500 Ω / □; the second transparent double-side conductive film has a thickness of 50-250 μm, a tensile strength of ≥78 MPa, a Ra of 0.2 μm, a light transmittance of 80-93%, and a square resistance of 2-500 Ω / □; and the third transparent single-side conductive film has a thickness of 50-250 μm, a tensile strength of ≥78 MPa, a Ra of 0.2 μm, a light transmittance of 80-93%, and a square resistance of 2-500 Ω / □.

8. The integrated heating function dimming film according to claim 1, wherein, The electrochromic layer comprises a light-adjusting material selected from at least one of liquid crystal light-adjusting material, electrochromic light-adjusting material, suspended particle light-adjusting material, and anisotropic metal sulfide nanoparticle light-adjusting material.

9. The integrated heating function dimming film according to claim 8, wherein, The electrochromic layer has a thickness of 10-300 μm, and the electrocaloric layer has a thickness of 5-100 μm.

10. A method of manufacturing the integrated heating function dimming film according to any one of claims 1 to 9, characterized in that, The method comprises the following steps: S1, preparing an electrochromic coating solution; S2, coating the electrochromic coating solution on a substrate to form an electrochromic layer; S2, preparing the electrocaloric coating liquid: adding the polar solvent, the main body resin, the dilution monomer and the photo-curing initiator into a container according to preset contents, fully stirring and mixing to obtain the electrocaloric coating liquid; S3, placing the electrochromic coating liquid between the first transparent single-side conductive film and the second transparent double-side conductive film to form the electrochromic structure; S4, coating the electrocaloric coating liquid on the side of the second transparent double-side conductive film away from the electrochromic coating layer to form the electrocaloric coating layer, attaching the third transparent single-side conductive film, and making the conductive side of the third transparent single-side conductive film close to the electrocaloric coating layer, and then ultraviolet curing to obtain the light control film integrated with the heating function.

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