Car body color changing film with repair coating on the surface

Abstract

The invention discloses a vehicle body color-changing film with a repair coating on the surface, wherein the vehicle body color-changing film comprises, from top to bottom, a first release film layer, a repair coating, a color coating, a substrate layer, a pressure-sensitive adhesive layer and a second release film layer; wherein the repair coating is mainly composed of hydroxyl-terminated polyurethane, epoxidized modified trans-1,4-polyisoprene rubber, a curing agent, a leveling agent, an ultraviolet absorber and a solvent. The vehicle body color-changing film of the invention has excellent self-repairing performance, yellowing resistance, stain resistance, strong acid rain resistance and high tensile strength.

Description

Technical Field

[0001] The invention relates to the technical field of color-changing films, and in particular to a car body color-changing film with a repair coating on the surface. Background Art

[0002] The car body color-changing film is a film with rich and diverse colors. It can be used to change the appearance of the whole car or part of the car by covering it as a whole. The car body color-changing film is mainly attached to the surface of the car body through polymer materials and is easy to remove. At present, the surface of the car body color-changing film on the market generally has a repair coating. When the car body encounters scratches or minor collisions, as long as the car body color-changing film itself is not damaged, small scratches can be automatically eliminated in a short time, or eliminated under heating conditions. Therefore, the repair coating is used for the car body color-changing film, which plays a good protective role on the car paint, can prevent the car paint from being scratched, and greatly reduce the overall impact of scratches on the appearance of the car.

[0003] In addition to the repair function, the repair coating of the car body color-changing film needs to have good yellowing resistance, stain resistance, acid rain resistance, etc., because it is exposed to high temperature, direct sunlight, dust, oil stains, acid rain and other harsh environments for a long time. At the same time, since the car body color-changing film needs to be stretched during the bonding process to prevent the chamfers or edges from being loosely bonded or deformed, the car body color-changing film needs to have certain stretching properties.

[0004] In actual production, the requirements for the car body color-changing film in terms of self-repairing performance, yellowing resistance, stain resistance, acid rain resistance, and tensile performance are contradictory, so the current car body color-changing film often provides a relatively balanced solution in terms of performance in all aspects. However, people's pursuit of the ultimate performance is constantly improving, which puts higher requirements on the car body color-changing film.

[0005] Therefore, it is urgent to develop a car body color-changing film with excellent self-repairing properties, yellowing resistance, stain resistance, strong acid rain resistance and high tensile strength. Summary of the invention

[0006] Based on the problems existing in the background technology, the present invention provides a car body color changing film with a repair coating on the surface.

[0007] The present invention is implemented by the following technical solutions:

[0008] A car body color-changing film with a repair coating on the surface, the car body color-changing film comprising, from top to bottom, a first release film layer, a repair coating, a color coating, a substrate layer, a pressure-sensitive adhesive layer, and a second release film layer;

[0009] The main components of the repair coating are hydroxyl-terminated polyurethane, epoxidized modified trans-1,4-polyisoprene rubber, curing agent, leveling agent, ultraviolet absorber and solvent.

[0010] Furthermore, the thickness of the repair coating is 20-50 μm.

[0011] Furthermore, the repair coating comprises the following components in parts by weight: 80-100 parts of hydroxyl-terminated polyurethane, 3-5 parts of epoxidized modified trans-1,4-polyisoprene rubber, 4-8 parts of curing agent, 1-3 parts of leveling agent, 1-3 parts of ultraviolet absorber and 150-200 parts of solvent.

[0012] Furthermore, the hydroxyl-terminated polyurethane is prepared by the following method:

[0013] The polyether triol is added into a vacuum reactor, vacuum dehydrated, diphenylmethane diisocyanate and catalyst dibutyltin dilaurate are added under nitrogen protection to catalyze the reaction, and then polypropylene glycol is added for end-capping to obtain the product.

[0014] Furthermore, the epoxidation-modified trans-1,4-polyisoprene rubber is prepared by the following method:

[0015] Trans-1,4-polyisoprene rubber is dissolved in toluene solvent, a formic acid catalyst is added, and hydrogen peroxide is used to carry out epoxidation reaction on the carbon-carbon double bonds of the trans-1,4-polyisoprene to obtain trans-1,4-polyisoprene rubber modified with epoxy groups.

[0016] Further, the curing agent is one of isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate or xylylene diisocyanate;

[0017] The leveling agent is a polydimethylsiloxane leveling agent;

[0018] The ultraviolet absorber is one of 2-hydroxy-4-octyloxybenzophenone, benzotriazole, benzophenone, 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester, etc.

[0019] The solvent is one or more of ethyl acetate, butyl acetate, dimethyl carbonate, butanone, toluene and xylene.

[0020] Furthermore, the thickness of the color coating is 20-30 μm; the color coating comprises the following components in parts by weight: 40-60 parts of acrylic resin, 20-30 parts of ethyl acetate, 0.1-2 parts of defoaming agent CF-16

[0021] And pigment 0.5-10 parts.

[0022] Furthermore, the thickness of the first release film layer and the second release film layer is 40-50 μm; the first release film layer and the second release film layer are made of PET film.

[0023] Furthermore, the thickness of the substrate layer is 100-150 μm; the substrate layer is made of thermoplastic polyurethane film.

[0024] Furthermore, the thickness of the pressure-sensitive adhesive layer is 20-30 μm; the pressure-sensitive adhesive layer is made of polyurethane or polyacrylate pressure-sensitive adhesive.

[0025] Furthermore, the method for preparing the car body color changing film comprises the following steps:

[0026] (1) using a wire rod to coat a polyacrylate pressure-sensitive adhesive on a second release film, i.e., a PET release film, having a thickness of 40 μm, and drying at 100° C. to form a 30 μm pressure-sensitive adhesive layer, and then laminating the layer with a thermoplastic polyurethane film having a thickness of 100 μm;

[0027] (2) applying the color coating paint to the other side of the thermoplastic polyurethane film by using a wire rod, and drying at 150° C. to form a 30 μm color coating;

[0028] (3) The repair coating paint is applied onto the color coating by using a wire rod, and dried and cured for 5 min by a step-by-step heating method of 90°C / 120°C / 150°C / 120°C / 90°C to obtain a 30 μm repair coating. A first release film, i.e., a PET release film, is composited on the surface of the repair coating with a thickness of 40 μm. The film is placed in an oven and aged at 45°C for 48 h. After the curing is completed and the visual online quality device is passed, a car body color-changing film with a repair coating on the surface is obtained.

[0029] Furthermore, the visual online quality device includes an image acquisition module, a calculation module and a detection module, wherein the image acquisition module is used to acquire images of the vehicle body color-changing film, the calculation module is used to calculate the grayscale value of the acquired images of the vehicle body color-changing film, and the detection module is used to perform threshold comparison on the calculation results obtained by the calculation module to determine whether the vehicle body color-changing film is qualified.

[0030] Further, the visual online quality device performs the following operations:

[0031] S1. Use the camera to obtain the qualified car body color change film image T1 as the detection standard, grayscale the image T1, and use the average value method to calculate the grayscale value of the RGB color image. The calculation formula is as follows:

[0032] P(i,j)=(R P (i,j)+G P (i,j)+B P (i,j)) / 3

[0033] Among them, R P , G P , B Pare the three color components of the pixel in image T1, and P(i,j) is the grayscale value of image T1;

[0034] S2. Obtain the image T2 of the color-changing film of the vehicle body to be detected and perform grayscale calculation. The calculation formula is as follows:

[0035] Q(i,j)=(R Q (i,j)+G Q (i,j)+B Q (i,j)) / 3

[0036] Among them, R Q , G Q , B Q are the three color components of the pixel in image T2, and Q(i,j) is the grayscale value of image T2;

[0037] S3. Determine whether the car body color-changing film is qualified by measuring the similarity between the image to be tested T2 and the standard template image T1; the standard sample image is P(i, j), the image to be tested is Q(i, j), and the mutual correlation coefficient of the two images is defined as ɑ:

[0038]

[0039] Among them, M and N are the length and width of image pixels. When the pixel values ​​of the image to be tested T2 and the standard sample image T1 are exactly the same, α=1; when there is a difference in the pixel values ​​of the image to be tested and the standard template image, α<1, and the smaller the value, the greater the difference between the image to be tested T2 and the standard sample image T1; a threshold β is set. When α<β, the quality of the car body color change film is judged to be unqualified and an alarm is issued.

[0040] Beneficial effects of the present invention:

[0041] 1. The repair coating in this application is mainly composed of hydroxyl-terminated polyurethane, which contains a large number of carbamate bonds. After the introduction of hydroxyl groups, the oxygen atoms on the hydroxyl groups will form hydrogen bonds with the carbamate bonds on the main chain of the polyurethane, thereby enhancing the self-repairing ability of the polyurethane.

[0042] 2. The carbon-carbon double bonds in the epoxidized trans-1,4-polyisoprene rubber molecular chain will undergo free radical polymerization with the carbon-carbon double bonds in the hydroxyl-terminated polyurethane resin, making the epoxidized trans-1,4-polyisoprene rubber act as a part of the soft segment in the entire repair coating, thereby improving the flexibility of the molecular chain, promoting the movement of the molecular chain to the fracture surface, and increasing the probability of forming hydrogen bonds on the fracture surface, thereby improving the self-healing efficiency of the repair coating.

[0043] 3. Epoxidized trans-1,4-polyisoprene rubber has high tensile properties and excellent stain resistance. Adding an appropriate amount of epoxidized trans-1,4-polyisoprene rubber can significantly improve the self-repairing properties of the car body color-changing film as well as its mechanical properties, yellowing resistance, stain resistance, and acid rain resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are used to provide further explanation of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0045] Figure 1 The present invention is a schematic diagram of the layer structure of a car body color changing film with a repair coating on the surface.

[0046] The numbers in the figure represent: 1-first release film layer; 2-repair coating layer; 3-color coating layer; 4-substrate layer; 5-pressure-sensitive adhesive layer; 6-second release film layer. DETAILED DESCRIPTION

[0047] In a specific embodiment, the layer structure of the car body color changing film is as follows Figure 1 As shown, from top to bottom, it includes a first release film layer 1, a repair coating layer 2, a color coating layer 3, a substrate layer 4, a pressure-sensitive adhesive layer 5 and a second release film layer 6.

[0048] In a specific embodiment, the thickness of the color coating is 30 μm; the color coating comprises the following components in parts by weight: 50 parts of acrylic resin, 25 parts of ethyl acetate, 0.8 parts of defoaming agent CF-16 and 5 parts of pigment.

[0049] In a specific embodiment, the thickness of the first release film layer and the second release film layer is 40 μm; the first release film layer and the second release film layer are commercially available PET films.

[0050] In a specific embodiment, the thickness of the substrate layer is 100 μm; the substrate layer is a commercially available thermoplastic polyurethane film.

[0051] In a specific implementation, the thickness of the pressure-sensitive adhesive layer is 30 μm; the pressure-sensitive adhesive layer is made of commercially available polyacrylate pressure-sensitive adhesive.

[0052] In a specific embodiment, the repair coating has a thickness of 30 μm, and the repair coating comprises the following components in parts by weight: 80-100 parts of hydroxyl-terminated polyurethane, 3-5 parts of epoxidized modified trans-1,4-polyisoprene rubber, 4-8 parts of curing agent, 1-3 parts of leveling agent, 1-3 parts of ultraviolet absorber and 150-200 parts of solvent.

[0053] Wherein, hydroxyl terminated polyurethane is prepared by the following method:

[0054] Add 372g of polyether triol into a vacuum reactor and dehydrate it under vacuum conditions at 105°C to control the moisture content below 250ppm. Then cool it to 85°C, add 78g of diphenylmethane diisocyanate and 0.23g of 10% dibutyltin dilaurate solution under nitrogen protection to catalyze the reaction for 2h, then add 312g of polypropylene glycol and carry out end-capping reaction for 50min to obtain hydroxyl-terminated polyurethane.

[0055] Epoxidized modified trans-1,4-polyisoprene rubber is prepared by the following method:

[0056] 10 g of trans-1,4-polyisoprene rubber was added to 100 mL of toluene solvent, and the temperature was raised to 60°C until it was completely dissolved. 6 mL of formic acid catalyst and 20 mL of hydrogen peroxide were added, and the epoxy reaction was carried out at 40°C for 5 h. After the epoxy reaction was completed, the product was neutralized with sodium bicarbonate, precipitated with ethanol, washed, and vacuum dried to constant weight.

[0057] In a specific embodiment, the method for preparing the car body color changing film comprises the following steps:

[0058] (1) using a wire rod to coat a polyacrylate pressure-sensitive adhesive on a second release film, i.e., a PET release film, having a thickness of 40 μm, and drying at 100° C. to form a 30 μm pressure-sensitive adhesive layer, and then laminating the layer with a thermoplastic polyurethane film having a thickness of 100 μm;

[0059] (2) applying the color coating paint to the other side of the thermoplastic polyurethane film by using a wire rod, and drying at 150° C. to form a 30 μm color coating;

[0060] (3) The repair coating is applied on the color coating by a wire rod, and dried and cured for 5 min by a step-by-step heating method of 90°C / 120°C / 150°C / 120°C / 90°C to obtain a 30 μm repair coating. A first release film, i.e., a PET release film, is composited on the surface of the repair coating with a thickness of 40 μm. The film is placed in an oven and aged at 45°C for 48 h. After the curing is completed and the visual online quality device is passed, a car body color-changing film with a repair coating on the surface is obtained.

[0061] The visual online quality device includes an image acquisition module, a calculation module and a detection module, wherein the image acquisition module is used to acquire images of the vehicle body color-changing film, the calculation module is used to calculate the grayscale value of the acquired images of the vehicle body color-changing film, and the detection module is used to perform threshold comparison on the calculation results obtained by the calculation module to determine whether the vehicle body color-changing film is qualified.

[0062] The visual online quality device performs the following operations:

[0063] S1. Use the camera to obtain the qualified car body color change film image T1 as the detection standard, grayscale the image T1, and use the average value method to calculate the grayscale value of the RGB color image. The calculation formula is as follows:

[0064] P(i,j)=(R P (i,j)+G P (i,j)+B P (i,j)) / 3

[0065] Among them, R P , G P , B P are the three color components of the pixel in image T1, and P(i,j) is the grayscale value of image T1;

[0066] S2. Obtain the image T2 of the color-changing film of the vehicle body to be detected and perform grayscale calculation. The calculation formula is as follows:

[0067] Q(i,j)=(R Q (i,j)+G Q (i,j)+B Q (i,j)) / 3

[0068] Among them, R Q , G Q , B Q are the three color components of the pixel in image T2, and Q(i,j) is the grayscale value of image T2;

[0069] S3. Determine whether the car body color-changing film is qualified by measuring the similarity between the image to be tested T2 and the standard template image T1; the standard sample image is P(i, j), the image to be tested is Q(i, j), and the mutual correlation coefficient of the two images is defined as ɑ:

[0070]

[0071] Among them, M and N are the length and width of image pixels. When the pixel values ​​of the image to be tested T2 and the standard sample image T1 are exactly the same, α=1; when there is a difference in the pixel values ​​of the image to be tested and the standard template image, α<1, and the smaller the value, the greater the difference between the image to be tested T2 and the standard sample image T1; a threshold β is set. When α<β, the quality of the car body color change film is judged to be unqualified and an alarm is issued.

[0072] Beneficial effects of the above invention: In the present invention, a visual online quality device is used to realize online detection of the quality of the car body color-changing film. The online quality device has a simple structure and efficient operation, which greatly improves the detection efficiency and accuracy.

[0073] Example

[0074] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0075] In the present invention, the main functional structure of the vehicle body color-changing film is the repair coating. Therefore, in the embodiments of the present invention, only the component content of the repair coating is changed, and the remaining layer structure composition and the preparation of the vehicle body color-changing film are as described above.

[0076] Example 1

[0077] The repair coating comprises the following components in parts by weight:

[0078] 90 parts of hydroxyl-terminated polyurethane, 5 parts of epoxidized modified trans-1,4-polyisoprene rubber, 6 parts of curing agent isophorone diisocyanate, 2 parts of leveling agent polydimethylsiloxane, 2 parts of ultraviolet absorber 2-hydroxy-4-n-octyloxybenzophenone and 180 parts of solvent ethyl acetate.

[0079] Example 2

[0080] The repair coating comprises the following components in parts by weight:

[0081] 90 parts of hydroxyl-terminated polyurethane, 3 parts of epoxidized modified trans-1,4-polyisoprene rubber, 6 parts of curing agent isophorone diisocyanate, 2 parts of leveling agent polydimethylsiloxane, 2 parts of ultraviolet absorber 2-hydroxy-4-n-octyloxybenzophenone and 180 parts of solvent ethyl acetate.

[0082] Comparative Example 1

[0083] The repair coating comprises the following components in parts by weight:

[0084] 90 parts of polyurethane, 6 parts of curing agent isophorone diisocyanate, 2 parts of leveling agent polydimethylsiloxane, 2 parts of ultraviolet absorber 2-hydroxy-4-n-octyloxybenzophenone and 180 parts of solvent ethyl acetate.

[0085] Comparative Example 2

[0086] 90 parts of polyurethane, 5 parts of epoxidized modified trans-1,4-polyisoprene rubber, 6 parts of curing agent isophorone diisocyanate, 2 parts of leveling agent polydimethylsiloxane, 2 parts of ultraviolet absorber 2-hydroxy-4-n-octyloxybenzophenone and 180 parts of solvent ethyl acetate.

[0087] Comparative Example 3

[0088] The repair coating comprises the following components in parts by weight:

[0089] 90 parts of hydroxyl-terminated polyurethane, 6 parts of curing agent isophorone diisocyanate, 2 parts of leveling agent polydimethylsiloxane, 2 parts of ultraviolet absorber 2-hydroxy-4-n-octyloxybenzophenone and 180 parts of solvent ethyl acetate.

[0090] Comparative Example 4

[0091] The repair coating comprises the following components in parts by weight:

[0092] 90 parts of hydroxyl-terminated polyurethane, 8 parts of epoxidized modified trans-1,4-polyisoprene rubber, 6 parts of curing agent isophorone diisocyanate, 2 parts of leveling agent polydimethylsiloxane, 2 parts of ultraviolet absorber 2-hydroxy-4-n-octyloxybenzophenone and 180 parts of solvent ethyl acetate.

[0093] Performance test of car body color changing film

[0094] 1. Repair speed: Use a copper brush to scratch the repair coating vigorously, then rinse the scratch with hot water at about 70°C, and use a stopwatch to record the time it takes to repair the scratch.

[0095] 2. Number of repairs: Use a copper brush to scratch the repair coating forcefully. After the scratch is repaired, repeatedly scratch the repair coating with the copper brush and record the number of times the repair coating can be repaired.

[0096] 3. Number of repairs after aging: Aging is carried out according to the method specified in GB / T 2423.3-2006 "Environmental testing for electrical and electronic products Part 2: Test method Experiment Cab: Constant humidity test", the temperature of the constant temperature and humidity test chamber is set to 85°C, the relative humidity is set to 85%, and the aging time is 500h. After aging, the number of repairs of the repair coating is tested with a copper brush.

[0097] 4. Tensile strength: tested according to the method of GB / T 1040.3-2006.

[0098] 5. Yellowing resistance: Car body color changing film is subjected to QUV xenon lamp aging test, and the car body color changing film is placed in a xenon lamp aging test chamber for testing; the xenon lamp irradiation power is 1500W / m 2 , the inner chamber temperature is 70℃, and the relative humidity is 65%; during the experiment, each experimental cycle includes 102min light plus 18min care plus water spray, and the water temperature is 20±5℃; the color parameters L of the test samples before and after aging are tested according to GB / T 36142-2018 * 、a * , b * , and calculate the color difference before and after the test The color difference calculation formula is: In the formula is the color difference of the sample before and after the test, △L * , △a* , △b * They are the color parameters L of the samples after the test. * 、a * , b * The difference compared with the value before the experiment.

[0099] 6. Anti-fouling performance: Use a Mark pen to write on the car body color change film at will, then wipe it with a cloth and observe the degree of wiping of the Mark handwriting. The ease of wiping is divided into three levels, A is very easy to wipe, B is general wiping, and C is not easy to wipe. The ease of wiping indicates the anti-fouling performance. The easier it is to wipe, the better the anti-fouling performance (A level), and the harder it is to wipe, the worse the anti-fouling performance (C level).

[0100] 7. Acid corrosion resistance (acid rain resistance): Take a small piece of the car body color-changing film, soak it in 0.1N sulfuric acid solution for 48 hours, then take it out and observe the degree of fogging on the surface of the sample. The severity of fogging is divided into 5 levels, namely: Level 1 represents none, Level 2 represents very slight, Level 3 represents slight, Level 4 represents general, and Level 5 represents severe. The degree of fogging indicates the acid corrosion resistance of the car body color-changing film. The lighter the fogging, the better the acid corrosion resistance of the car body color-changing film (Level 1); the more severe the fogging, the worse the acid corrosion resistance of the car body color-changing film (Level 5).

[0101] The test results are shown in Table 1.

[0102] Table 1 Test results of various embodiments and comparative examples

[0103]

[0104] It can be seen from the data in Table 1 that when the main component of the repair coating in Comparative Example 1 is polyurethane, the various properties of the repair coating are not as good as those in Examples 1 and 2. In Comparative Example 2, epoxidized modified trans-1,4-polyisoprene rubber is added to the repair coating components, and the various properties of the repair coating are significantly improved compared with Comparative Example 1, indicating that the addition of epoxidized modified trans-1,4-polyisoprene rubber can improve the performance of the repair coating. The test results of Examples 1, 2 and Comparative Example 3 also further illustrate that with the addition of epoxidized modified trans-1,4-polyisoprene rubber, the number of repairs and the speed of the repair coating are significantly increased. At the same time, the addition of epoxidized modified trans-1,4-polyisoprene rubber significantly improves the mechanical properties, yellowing resistance, and acid resistance of the repair coating. However, from the results of Comparative Example 4, it can be seen that as the amount of epoxidized modified trans-1,4-polyisoprene rubber added increases, the repair coating and the number of repairs, tensile strength and acid rain resistance have a downward trend. This is because too much epoxidized modified trans-1,4-polyisoprene rubber added will lead to reduced compatibility with hydroxyl-terminated polyurethane, thereby reducing the performance of the repair coating. Therefore, the amount of epoxidized modified trans-1,4-polyisoprene rubber added in the present invention is 3-5 parts, which should not be too much.

[0105] Finally, it should be noted that the above-mentioned embodiments only express several implementation methods of the present invention and are not intended to limit the invention. For those skilled in the art, any modification, equivalent replacement, improvement, etc. made without departing from the concept of the present invention should be included in the protection scope of the invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A car body color-changing film with a repair coating on the surface, characterized in that: The vehicle body color-changing film includes, from top to bottom, a first release film layer, a repair coating layer, a color coating layer, a substrate layer, a pressure-sensitive adhesive layer, and a second release film layer; The main components of the repair coating are hydroxyl-terminated polyurethane, epoxidized modified trans-1,4-polyisoprene rubber, curing agent, leveling agent, ultraviolet absorber and solvent; The repair coating comprises the following components in parts by weight: 80-100 parts of hydroxyl-terminated polyurethane, 3-5 parts of epoxidized modified trans-1,4-polyisoprene rubber, 4-8 parts of curing agent, 1-3 parts of leveling agent, 1-3 parts of ultraviolet absorber and 150-200 parts of solvent; The hydroxyl-terminated polyurethane is prepared by the following method: adding polyether triol into a vacuum reactor, vacuum dehydrating, adding diphenylmethane diisocyanate and a catalyst dibutyltin dilaurate to catalyze the reaction under nitrogen protection conditions, and then adding polypropylene glycol 1000 to terminate the reaction; The epoxidation-modified trans-1,4-polyisoprene rubber is prepared by the following method: dissolving the trans-1,4-polyisoprene rubber in a toluene solvent, adding a formic acid catalyst, and using hydrogen peroxide to carry out an epoxidation reaction on the carbon-carbon double bonds of the trans-1,4-polyisoprene to obtain the trans-1,4-polyisoprene rubber modified with epoxy groups.

2. The car body color-changing film with a repair coating on the surface as claimed in claim 1, characterized in that: The thickness of the repair coating is 20-50 μm.

3. The car body color-changing film with a repair coating on the surface as claimed in claim 1, characterized in that: The curing agent is one of isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate or xylylene diisocyanate; The leveling agent is a polydimethylsiloxane leveling agent; The ultraviolet absorber is one of 2-hydroxy-4-n-octyloxybenzophenone, benzotriazole, and 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl ester; The solvent is one or more of ethyl acetate, butyl acetate, dimethyl carbonate, butanone, toluene and xylene.

4. The car body color changing film with a repair coating on the surface as claimed in claim 1, characterized in that: The thickness of the color coating is 20-30 μm; the color coating comprises the following components in parts by weight: 40-60 parts of acrylic resin, 20-30 parts of ethyl acetate, 0.1-2 parts of defoaming agent CF-16 and 0.5-10 parts of pigment.

5. The car body color changing film with a repair coating on the surface as claimed in claim 1, characterized in that: The thickness of the first release film layer and the second release film layer is 40-50 μm; the first release film layer and the second release film layer are made of PET film.

6. The car body color changing film with a repair coating on the surface as claimed in claim 1, characterized in that: The thickness of the substrate layer is 100-150 μm; the substrate layer is made of thermoplastic polyurethane film.

7. The car body color changing film with a repair coating on the surface as claimed in claim 1, characterized in that: The thickness of the pressure-sensitive adhesive layer is 20-30 μm; the pressure-sensitive adhesive layer is made of polyurethane or polyacrylate pressure-sensitive adhesive.

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