Automobile sunroof light control film and preparation method thereof

Abstract

The application relates to a preparation method of an automobile sunroof light-adjusting film, which comprises the following steps: S1: fluorine-containing terephthalic acid, a dihydric alcohol, a catalyst and a stabilizer are configured into a slurry, esterification is carried out under certain pressure and temperature conditions, and an esterification product is obtained; the dihydric alcohol is composed of ethylene glycol and an ethylene glycol derivative monomer containing a bipyridine salt; S2: the esterification product is subjected to a polycondensation reaction under certain pressure and temperature conditions, and after the reaction, the modified PET resin chip is obtained by extruding and slicing; S3: the modified PET resin chip is compounded with hollow microsphere particles, zinc trifluoromethane sulfonate, a leveling agent and a wetting agent, is uniformly mixed, is coated between two layers of PET conductive film layers, and after heating and curing, the automobile sunroof light-adjusting film is obtained. The automobile sunroof light-adjusting film prepared by the application solves the problems that the existing automobile sunroof film cannot realize light adjustment, the heat insulation effect is not ideal, the service life is short and the like, and can meet the long-term use requirements in severe climate environments.

Description

Technical Field

[0001] This invention relates to the technical field of thin films, and more particularly to a sunroof dimming film for automobiles and its preparation method. Background Technology

[0002] Cars bring great convenience to people's travel and, after years of development, have become a common household item, with annual car sales exceeding 20 million units nationwide. Car sunroofs, installed on the roof, effectively improve air circulation and increase the intake of fresh air. They also meet the needs of mobile photography. However, in hot summers or cold winters, drivers close the car and turn on the air conditioning to adjust the cabin to a comfortable temperature. Traditional sunroof glass lacks light-dampening capabilities, allowing strong sunlight or ultraviolet rays to directly enter the cabin, reducing the comfort of passengers. A small number of color-changing car sunroofs use liquid crystal dimming films, which can switch to an opaque state when the film is powered on, but these suffer from problems such as poor heat insulation and short lifespan. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the present invention provides a method for preparing a car sunroof dimming film to solve the problems of existing car sunroof films being unable to achieve dimming function, having unsatisfactory heat insulation effect, and having a short service life, so as to meet the requirements of long-term use of car sunroof dimming films in harsh climatic environments.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for preparing a car sunroof dimming film, the method comprising the following steps:

[0006] S1: Fluorinated terephthalic acid, diol, catalyst and stabilizer are prepared into a slurry, and esterification reaction is carried out under the conditions of pressure of 0.1-0.3 MPa and temperature of 220-260℃ to obtain esterified products; the diol is composed of ethylene glycol and ethylene glycol derivative monomers containing bipyridine salt;

[0007] S2: The ester obtained in step S1 is subjected to polycondensation reaction under a pressure of 10-1000 Pa and a temperature of 240-280 °C for 1-4 hours. After extrusion and slicing by screw extruder, modified PET resin chips are obtained.

[0008] S3: The modified PET resin chips obtained in step S2 are compounded with hollow microspheres, zinc trifluoromethanesulfonate, leveling agent, and wetting agent. After uniform mixing, the mixture is coated between two layers of PET conductive film. After heating and curing, the automotive sunroof dimming film is obtained. This invention, by compounding modified PET resin chips with hollow microspheres, zinc trifluoromethanesulfonate, leveling agent, and wetting agent and coating them between two layers of PET conductive film, produces an automotive sunroof dimming film. In its initial state, it has high light transmittance; after being energized, it exhibits a rapid response dimming function and provides good heat insulation.

[0009] Preferably, the fluorinated terephthalic acid is at least one selected from 2,5-difluoroterephthalic acid, 2,3,5,6-tetrafluoroterephthalic acid, and 2-fluoroterephthalic acid. This invention uses fluorinated terephthalic acid as a reactive monomer for polyester. While ensuring good film-forming properties of the polyester, it introduces fluorine atoms into the polymer film. Compared to directly adding fluorinated additives, the fluorinated polymer film of this invention effectively improves the high-temperature resistance and weather resistance of automotive window films.

[0010] Preferably, the catalyst is at least one selected from antimony trioxide, antimony glycol, isopropyl titanate, and butyl titanate. The catalyst of this invention is advantageous in promoting the esterification reaction of fluorinated terephthalic acid and diols.

[0011] Preferably, the stabilizer is at least one selected from trimethyl phosphate, dimethyl phosphate, triethyl phosphate, diethyl phosphate, triphenyl phosphate, and diphenyl phosphate. The use of phosphate ester stabilizers in this invention is advantageous in preventing the thermal decomposition and side reactions of modified PET resin chips under high-temperature conditions.

[0012] Preferably, the chemical formula of the ethylene glycol derivative containing the bipyridine salt is shown in structural formula I.

[0013]

[0014] In the formula, R1 is selected from methyl, ethyl, or propyl; at least one of R2, R3, R4, and R5 is selected from fluorine; and the rest are hydrogen. － BF4 － or PF6 － This invention relates to an ethylene glycol derivative containing bipyridine salt, wherein the two hydroxyl groups can undergo copolymerization and crosslinking reactions with the carboxyl groups of fluorinated terephthalic acid to form a polymer; the fluorine at one end further increases the fluorine content of the modified PET, thereby improving the high-temperature resistance and weather resistance of the automotive window film and extending its service life; the bipyridine salt functional group undergoes a reversible redox reaction under energized conditions, enabling the automotive sunroof film to change color and thus have a dimming effect; furthermore, the ethylene glycol derivative containing bipyridine salt of this invention achieves good heat insulation through the synergistic effect of the fluorinated groups and the bipyridine salt functional group.

[0015] The method for preparing the ethylene glycol derivative containing bipyridine salt is as follows: 4,4'-bipyridine and a haloalkane are dissolved in a tetrahydrofuran solution at a molar ratio of 1:1. After heating and reflux, the reaction product obtained by filtration is dissolved in a tetrahydrofuran solution. An excess of sodium tetrafluoroborate is added to carry out an ion exchange reaction to obtain a monosubstituted bipyridine derivative. The bipyridine derivative is further subjected to a substitution reaction with 2-bromoethyl acrylate to obtain a vinyl bipyridine salt compound. The vinyl bipyridine salt compound at a molar ratio of 1:1 is then subjected to an addition reaction with divinyl ethylene glycol under an inert gas protection. Finally, fluorinated vinylidene is added to carry out an addition reaction to obtain the ethylene glycol derivative containing bipyridine salt.

[0016] Preferably, the haloalkane is at least one selected from bromomethane, bromoethane, and bromopropane.

[0017] Preferably, the fluorinated ethylene is at least one of tetrafluoroethylene, trifluoroethylene, 1,1-difluoroethylene, and fluorinated ethylene.

[0018] Preferably, the hollow microsphere particles are prepared by: firstly, an addition polymerization reaction of vinyl-POSS, acrylamide, and acrylic monomers; then, the reaction product is mixed with titanium hydroxide and an organic acid, calcined simultaneously, followed by the addition of polyaniline for ball milling, and finally granulation and sieving. This invention utilizes the simultaneous calcination of a network-structured organic-inorganic hybrid product resulting from the addition polymerization of vinyl-POSS, acrylamide, and acrylic monomers with titanium hydroxide. This process causes the structure of the organic-inorganic hybrid product to break and collapse, facilitating further ball milling and granulation to obtain a composite microparticle additive. Furthermore, the simultaneous calcination reaction decomposes titanium hydroxide into titanium dioxide, resulting in a silicon-rich composite microparticle additive with in-situ titanium dioxide doping. The hollow microsphere particles prepared by this invention not only provide automotive window films with excellent optical properties such as high transmission, low reflection, and low haze, but also excellent performance characteristics such as high temperature resistance and heat insulation, meeting the long-term use requirements of automotive windows under harsh conditions. In this invention, the vinyl-POSS is preferably octavinyl-POSS (also known as octavinyl-octasilylsesquioxane, CAS: 69655-76-1). By ball milling the blend with polyaniline, the conductivity of the sunroof dimming film is improved, ensuring the rapid color-changing response of the sunroof dimming film of this invention.

[0019] Preferably, the acrylic monomer is at least one selected from acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and methyl methacrylate.

[0020] Preferably, the organic acid is at least one selected from propionic acid, maleic acid, fumaric acid, adipic acid, malic acid, citric acid, and lactic acid.

[0021] Preferably, the leveling agent is at least one of BYK310, BYK306, BYK300, TEGO450, and TEGO4000.

[0022] Preferably, the wetting agent is isopropyl tetradecanoate and / or isopropyl hexadecanoate.

[0023] Another aspect of the present invention is to provide a sunroof dimming film for automobiles, wherein the sunroof dimming film is prepared by the method described above for preparing a sunroof dimming film for automobiles.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention relates to a car sunroof dimming film, which obtains modified PET resin chips by grafting bipyridine salts onto the side chains of the PET main structure through a monomer copolymerization reaction, combined with the synergistic effect of hollow microsphere particles. It has good light transmittance when initially unenergized and dimming function when energized. This solves the problems of existing car sunroof films that cannot achieve dimming function, have unsatisfactory heat insulation effect, and short service life, and can meet the long-term use requirements of car sunroof dimming films in harsh climatic environments. Detailed Implementation

[0026] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0027] Example 1

[0028] The method for preparing the automotive sunroof dimming film in this embodiment includes the following steps:

[0029] S1: 2,5-Difluoroterephthalic acid, diol, antimony trioxide, and trimethyl phosphate are prepared into a slurry and subjected to esterification reaction at a pressure of 0.2 MPa and a temperature of 230°C to obtain an esterified product; the diol is composed of ethylene glycol in a molar ratio of 5:1 and an ethylene glycol derivative monomer containing bipyridinium salt; the molar ratio of 2,5-difluoroterephthalic acid and diol is 1:1.5, and the antimony trioxide and trimethyl phosphate account for 1% and 0.5% of the slurry by mass, respectively.

[0030] S2: The ester obtained in step S1 is subjected to polycondensation reaction under a pressure of 500 Pa and a temperature of 260 °C for 2 hours. After extrusion and slicing by screw extruder, modified PET resin chips are obtained.

[0031] S3: The modified PET resin chips obtained in step S2 are compounded with hollow microspheres, zinc trifluoromethanesulfonate, leveling agent BYK310, and isopropyl myristate. After uniform mixing, the mixture is coated between two layers of PET conductive film. After curing at 150°C, the automotive sunroof dimming film is obtained, with a total film thickness of 300 μm. In step S3, the raw materials, by weight, are 85 parts modified PET resin chips, 12 parts hollow microspheres, 8 parts zinc trifluoromethanesulfonate, 3 parts leveling agent BYK310, and 5 parts isopropyl myristate. In this embodiment, the PET conductive film refers to a PET film with ITO coated on its surface (the same applies to other embodiments).

[0032] The chemical formula of the ethylene glycol derivative containing bipyridine salt is shown in structural formula I.

[0033]

[0034] In the formula, R1 is selected from methyl, R2 is selected from fluorine, and the remaining R3, R4 and R5 are hydrogen, X － BF4 － .

[0035] The method for preparing the ethylene glycol derivative containing bipyridine salt is as follows: 4,4'-bipyridine and bromomethane are dissolved in tetrahydrofuran solution at a molar ratio of 1:1. After reflux reaction at 90°C, the reaction product obtained by filtration is dissolved in tetrahydrofuran solution. Excess sodium tetrafluoroborate is added to carry out an ion exchange reaction to obtain a monosubstituted bipyridine derivative. The bipyridine derivative is added to 2-bromoethyl acrylate at a molar ratio of 1:1.1 to continue the substitution reaction. After separation, a vinyl bipyridine salt compound is obtained. The vinyl bipyridine salt compound at a molar ratio of 1:1 is then added to divinyl ethylene glycol under inert gas protection. A small amount of ammonium persulfate can be added to promote the reaction. Finally, vinyl fluoride is added to continue the addition reaction to obtain the ethylene glycol derivative containing bipyridine salt.

[0036] The hollow microspheres are prepared by: firstly, an addition polymerization reaction of vinyl-POSS, acrylamide, and methacrylic acid monomers in a molar ratio of 2:1:4; then, the reaction product is mixed with titanium hydroxide and fumaric acid, calcined simultaneously, and then polyaniline is added for blending and ball milling, followed by granulation and sieving. The mass ratio of the reaction product to titanium hydroxide and fumaric acid is 10:3:1, and the mass ratio of the calcined product to polyaniline is 5:1. During the calcination operation, the calcination temperature is 660℃ and the calcination time is 2 hours; during the ball milling operation, zirconia balls are used as the milling medium, the ball-to-material ratio is 1:2, the ball milling time is 240 min, and the ball mill speed is 600 r / min; during the granulation operation, the operating temperature of the spray granulator is 120℃; and during the sieving operation, the particles are sieved through a 100-mesh sieve and a 500-mesh sieve.

[0037] Example 2

[0038] The method for preparing the automotive sunroof dimming film in this embodiment includes the following steps:

[0039] S1: 2,3,5,6-Tetrafluoroterephthalic acid, a diol, isopropyl titanate, and triethyl phosphate are prepared into a slurry and subjected to an esterification reaction at a pressure of 0.2 MPa and a temperature of 260°C to obtain an esterified product; the diol is composed of ethylene glycol in a molar ratio of 6:1 and an ethylene glycol derivative monomer containing a bipyridinium salt; the molar ratio of 2,3,5,6-tetrafluoroterephthalic acid to the diol is 1:1.5, and the mass percentages of isopropyl titanate and triethyl phosphate in the slurry are 1.1% and 0.25%, respectively.

[0040] S2: The ester obtained in step S1 is subjected to polycondensation reaction under a pressure of 300 Pa and a temperature of 240 °C for 4 hours. After extrusion and slicing by screw extruder, modified PET resin chips are obtained.

[0041] S3: The modified PET resin chips obtained in step S2 are compounded with hollow microspheres, zinc trifluoromethanesulfonate, leveling agent TEGO450, and isopropyl hexadecanoate. After uniform mixing, the mixture is coated between two layers of PET conductive film. After curing at 150°C, the automotive sunroof dimming film is obtained, with a total film thickness of 250 μm. In step S3, the raw materials, by weight, are 80 parts modified PET resin chips, 10 parts hollow microspheres, 7 parts zinc trifluoromethanesulfonate, 3 parts leveling agent TEGO450, and 3.5 parts isopropyl hexadecanoate.

[0042] The chemical formula of the ethylene glycol derivative containing bipyridine salt is shown in structural formula I.

[0043]

[0044] In the formula, R1 is selected from ethyl, R2 and R3 are selected from fluorine, and the remaining R4 and R5 are hydrogen, X － BF4 － .

[0045] The method for preparing the ethylene glycol derivative containing bipyridine salt is as follows: 4,4'-bipyridine and bromoethane are dissolved in tetrahydrofuran solution at a molar ratio of 1:1. After reflux reaction at 95°C, the reaction product obtained by filtration is dissolved in tetrahydrofuran solution. Excess sodium tetrafluoroborate is added to carry out an ion exchange reaction to obtain a monosubstituted bipyridine derivative. The bipyridine derivative is added to 2-bromoethyl acrylate at a molar ratio of 1:1.1 to continue the substitution reaction. After separation, a vinyl bipyridine salt compound is obtained. The vinyl bipyridine salt compound at a molar ratio of 1:1 is then added to divinyl ethylene glycol under inert gas protection. A small amount of ammonium persulfate can be added to promote the reaction. Finally, 1,1-difluoroethylene is added to continue the addition reaction to obtain the ethylene glycol derivative containing bipyridine salt.

[0046] The hollow microspheres are prepared by: firstly, an addition polymerization reaction of vinyl-POSS, acrylamide, and methyl acrylate monomers in a molar ratio of 2:1:8; then, the reaction product is mixed with titanium hydroxide and adipic acid, calcined simultaneously, and then polyaniline is added for blending and ball milling, followed by granulation and sieving. The mass ratio of the reaction product to titanium hydroxide and adipic acid is 6:2:1, and the mass ratio of the calcined product to polyaniline is 3:1. During calcination, the calcination temperature is 650℃ and the calcination time is 3 hours; during ball milling, zirconia balls are used as the milling medium, the ball-to-material ratio is 2:5, the milling time is 270 min, and the mill speed is 600 r / min; during granulation, the operating temperature of the spray granulator is 120℃; and during sieving, the particles are sieved through a 100-mesh screen and then through a 500-mesh screen.

[0047] Example 3

[0048] The method for preparing the automotive sunroof dimming film in this embodiment includes the following steps:

[0049] S1: 2-Fluorophthalic acid, diol, tetrabutyl titanate, and triphenyl phosphate are prepared into a slurry and subjected to esterification reaction at a pressure of 0.15 MPa and a temperature of 260°C to obtain an esterified product; the diol is composed of ethylene glycol in a molar ratio of 6:1 and an ethylene glycol derivative monomer containing bipyridinium salt; the molar ratio of 2-fluoroterephthalic acid to diol is 1:1.5, and the mass percentages of tetrabutyl titanate and triphenyl phosphate in the slurry are 0.8% and 0.15%, respectively.

[0050] S2: The ester obtained in step S1 is subjected to polycondensation reaction under a pressure of 400 Pa and a temperature of 280 °C for 4 hours. After extrusion and slicing by screw extruder, modified PET resin chips are obtained.

[0051] S3: The modified PET resin chips obtained in step S2 are compounded with hollow microspheres, zinc trifluoromethanesulfonate, leveling agent BYK306, and isopropyl myristate. After uniform mixing, the mixture is coated between two layers of PET conductive film. After curing at 150°C, the automotive sunroof dimming film is obtained, with a total film thickness of 300 μm. In step S3, the raw materials, by weight, are 90 parts modified PET resin chips, 15 parts hollow microspheres, 10 parts zinc trifluoromethanesulfonate, 3.5 parts leveling agent BYK306, and 2.5 parts isopropyl myristate.

[0052] The chemical formula of the ethylene glycol derivative containing bipyridine salt is shown in structural formula I.

[0053]

[0054] In the formula, R1 is selected from propyl, R2, R3 and R4 are selected from fluorine, R5 is hydrogen, and X is hydrogen. － BF4 － .

[0055] The method for preparing the ethylene glycol derivative containing bipyridine salt is as follows: 4,4'-bipyridine and bromopropane are dissolved in tetrahydrofuran solution at a molar ratio of 1:1. After reflux reaction at 90°C, the reaction product obtained by filtration is dissolved in tetrahydrofuran solution. Excess sodium tetrafluoroborate is added to carry out an ion exchange reaction to obtain a monosubstituted bipyridine derivative. The bipyridine derivative is added to 2-bromoethyl acrylate at a molar ratio of 1:1.1 to continue the substitution reaction. After separation, a vinyl bipyridine salt compound is obtained. The vinyl bipyridine salt compound at a molar ratio of 1:1 is then added to divinyl ethylene glycol under inert gas protection. A small amount of ammonium persulfate can be added to promote the reaction. Finally, trifluoroethylene is added to continue the addition reaction to obtain the ethylene glycol derivative containing bipyridine salt.

[0056] The hollow microspheres are prepared by: firstly, an addition polymerization reaction of vinyl-POSS, acrylamide, and methyl methacrylate monomers in a molar ratio of 2:1:6; then, the reaction product is mixed with titanium hydroxide and lactic acid, calcined simultaneously, and then polyaniline is added for blending and ball milling, followed by granulation and sieving. The mass ratio of the reaction product to titanium hydroxide and lactic acid is 10:3:1, and the mass ratio of the calcined product to polyaniline is 5:1. During the calcination operation, the calcination temperature is 650℃, and the calcination time is 1.5 hours; during the ball milling operation, zirconia balls are used as the milling medium, the ball-to-material ratio is 1:2, the ball milling time is 200 minutes, and the ball mill speed is 600 r / min; during the granulation operation, the operating temperature of the spray granulator is 120℃; and during the sieving operation, the microspheres are sieved through a 10-mesh sieve and a 500-mesh sieve.

[0057] Example 4

[0058] The preparation method of the automotive sunroof dimming film in this embodiment is basically the same as that in Example 1 in terms of film structure, raw materials, and preparation steps. The difference is that in the preparation method of the automotive sunroof dimming film in this embodiment, 2,3,5,6-tetrafluoroterephthalic acid is used instead of 2,5-difluoroterephthalic acid in the modification method of the modified PET resin chips; dimethyl phosphate is used instead of trimethyl phosphate as the stabilizer; and the diol is composed of ethylene glycol and a bipyridine salt-containing ethylene glycol derivative in a molar ratio of 4:1. The chemical formula of the bipyridine salt-containing ethylene glycol derivative is shown in structural formula I.

[0059]

[0060] In the formula, R1 is selected from ethyl, R2, R3, R4 and R5 are all selected from fluorine, and X － For PF6 － .

[0061] Example 5

[0062] The preparation method of the automotive sunroof dimming film in this embodiment is basically the same as that in Example 1 in terms of film structure, raw materials, and preparation steps. The difference is that in the preparation method of the automotive sunroof dimming film in this embodiment, 2,3,5,6-tetrafluoroterephthalic acid is used instead of 2,5-difluoroterephthalic acid in the modification method of the modified PET resin chips; triethyl phosphate is used instead of trimethyl phosphate as the stabilizer; and the diol is composed of ethylene glycol and a bipyridine salt-containing ethylene glycol derivative in a molar ratio of 6:1. The chemical formula of the bipyridine salt-containing ethylene glycol derivative is shown in structural formula I.

[0063]

[0064] In the formula, R1 is selected from propyl, R2 and R3 are selected from fluorine, and the rest, R4 and R5 are hydrogen, X － For PF6 － .

[0065] Example 6

[0066] The preparation method of the automotive sunroof dimming film in this embodiment is basically the same as that in Example 1 in terms of film structure, raw materials, and preparation steps. The difference is that in the preparation method of the automotive sunroof dimming film in this embodiment, 2-fluoroterephthalic acid is used instead of 2,5-difluoroterephthalic acid in the modification method of the modified PET resin chips; triphenyl phosphate is used instead of trimethyl phosphate as the stabilizer; and the diol is composed of ethylene glycol and a bipyridine salt-containing ethylene glycol derivative in a molar ratio of 7:1. The chemical formula of the bipyridine salt-containing ethylene glycol derivative is shown in structural formula I.

[0067]

[0068] In the formula, R1 is selected from propyl, R2, R3 and R4 are selected from fluorine, R5 is hydrogen, and X is hydrogen. － BF4 － .

[0069] The automotive sunroof dimming films prepared in Examples 1-6 were subjected to performance tests, and the performance results are shown in Table 1.

[0070] Table 1

[0071]

[0072] Therefore, it is evident that this invention patent has significant advantages over currently used technologies. The basic principles, main features, and advantages of this invention have been shown and described above. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for preparing a car sunroof dimming film, characterized in that, The preparation method includes the following steps: S1: Fluorinated terephthalic acid, diol, catalyst and stabilizer are prepared into a slurry, and esterification reaction is carried out under the conditions of pressure of 0.1-0.3 MPa and temperature of 220-260℃ to obtain esterified products; the diol is composed of ethylene glycol and ethylene glycol derivative monomers containing bipyridine salt; S2: The ester obtained in step S1 is subjected to polycondensation reaction under a pressure of 10-1000 Pa and a temperature of 240-280 °C for 1-4 hours. After extrusion and slicing by screw extruder, modified PET resin chips are obtained. S3: The modified PET resin chips obtained in step S2 are compounded with hollow microspheres, zinc trifluoromethanesulfonate, leveling agent and wetting agent. After being mixed evenly, the mixture is coated between two layers of PET conductive film. After heating and curing, the automotive sunroof dimming film is obtained.

2. The method for preparing the automotive sunroof dimming film as described in claim 1, characterized in that, The fluorinated terephthalic acid is at least one of 2,5-difluoroterephthalic acid, 2,3,5,6-tetrafluoroterephthalic acid, and 2-fluoroterephthalic acid.

3. The method for preparing the automotive sunroof dimming film as described in claim 1, characterized in that, The catalyst is at least one of antimony trioxide, antimony glycol, isopropyl titanate, and butyl titanate.

4. The method for preparing the automotive sunroof dimming film as described in claim 1, characterized in that, The stabilizer is at least one of trimethyl phosphate, dimethyl phosphate, triethyl phosphate, diethyl phosphate, triphenyl phosphate, and diphenyl phosphate.

5. The method for preparing the automotive sunroof dimming film as described in claim 1, characterized in that, The chemical formula of the ethylene glycol derivative containing bipyridine salt is shown in structural formula I. Structural Formula I, In the formula, R1 is selected from methyl, ethyl, or propyl; at least one of R2, R3, R4, and R5 is selected from fluorine; and the rest are hydrogen. － BF4 － or PF6 － .

6. The method for preparing the automotive sunroof dimming film as described in claim 1, characterized in that, The hollow microspheres are prepared by: firstly, by addition polymerization of vinyl-POSS, acrylamide and acrylic monomers; then, by mixing the reaction product with titanium hydroxide and organic acid, calcining simultaneously, adding polyaniline for blending and ball milling, and then granulating and sieving.

7. The method for preparing the automotive sunroof dimming film as described in claim 6, characterized in that, The acrylic monomer is at least one of acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and methyl methacrylate.

8. The method for preparing the automotive sunroof dimming film as described in claim 1, characterized in that, The leveling agent is at least one of BYK310, BYK306, BYK300, TEGO450, and TEGO4000.

9. The method for preparing the automotive sunroof dimming film as described in claim 1, characterized in that, The wetting agent is isopropyl tetradecanoate and / or isopropyl hexadecanoate.

10. A car sunroof dimming film, characterized in that, The automotive sunroof dimming film is prepared by the method for preparing automotive sunroof dimming film as described in any one of claims 1 to 9.

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