An environment-friendly heat-insulating automobile paint surface protection film and a preparation method thereof

Abstract

The application belongs to the technical field of automobile paint surface protection film, and particularly relates to an environment-friendly heat-insulating automobile paint surface protection film and a preparation method thereof. The environment-friendly heat-insulating automobile paint surface protection film comprises, from top to bottom, a protection film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer and a release film. The heat-insulating coating comprises the following raw materials in parts by mass: 100 parts of a water-based polyurethane resin emulsion, 15-25 parts of a fatty acid ester modified heat-insulating compound, 1-2 parts of an ultraviolet absorber and 5-8 parts of an additive. The heat-insulating compound comprises glass fiber powder, hollow glass microbeads and nano rare earth oxides. The environment-friendly heat-insulating automobile paint surface protection film has the advantages of high light transmittance, good heat-insulating performance, good ultraviolet resistance, good ductility and environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of automotive paint protection film technology, specifically relating to an environmentally friendly heat-insulating automotive paint protection film and its preparation method. Background Technology

[0002] The manufacturing process of original factory car paint is demanding and complex, resulting in a paint surface with excellent adhesion, uniformity, gloss, corrosion resistance, and durability. However, once the original factory paint is damaged due to scratches, abrasions, corrosion, or improper repairs during subsequent use, it is difficult to restore. Therefore, in order to protect the original factory car paint, car paint protection film has emerged.

[0003] However, with the rapid development of new energy vehicles and the frequent occurrence of extreme high temperatures globally, the demand for thermal energy management of automobiles is increasing. Therefore, in addition to focusing on the heat insulation and UV protection functions of automotive paint protection films, consumers are paying more and more attention to them.

[0004] There are few reports on heat-insulating automotive paint protection films in the current technology. The main materials include PVC, polyimide, and thermoplastic polyurethane. Among them, PVC has poor chemical stability, is prone to yellowing and brittleness, has poor ductility, and cannot self-repair, and has been phased out by the market. Chinese patent CN105111483B discloses a sun-protective and heat-insulating automotive film and its preparation method. The automotive film includes a polyimide substrate layer; a heat insulation layer coated on the inner surface of the substrate layer, which is mainly composed of modified potassium hexatitanate whiskers, water-based epoxy resin, and acrylic resin; an anti-ultraviolet layer coated on the surface of the heat insulation layer; a sun protection layer coated on the outer surface of the substrate layer, which is mainly composed of nano-cerium dioxide, ultraviolet absorbers, and acrylic resin; a wear-resistant layer coated on the surface of the sun protection layer; a protective film layer; and an adhesive layer. The protective film layer is detachably bonded to the surface of the anti-ultraviolet layer through the adhesive layer. However, the ultraviolet absorption rate of this technical solution can only reach 98.9%.

[0005] Chinese patent CN112321878B discloses a self-healing polyurethane heat insulation film, its preparation method, and its application. The heat insulation film comprises a thermoplastic polyurethane film layer, a heat insulation layer, and a self-cleaning coating arranged sequentially. The raw material formulation of the thermoplastic polyurethane film layer includes TPU masterbatch and modified nano-indium antimony oxide. The raw material formulation of the heat insulation layer includes tungsten trioxide powder, dispersant, photoinitiator, polyurethane acrylate, tridecafluorooctyl methacrylate, 2-(perfluorooctyl)ethyl methacrylate, hollow glass microspheres, and a crosslinking agent. This technical solution provides a heat insulation film with good heat insulation performance, reducing light transmission and heat transfer, producing heat insulation, flame retardant, and wear-resistant effects, and also has self-healing function and good scratch resistance. However, the heat insulation layer of this technical solution contains tridecafluorooctyl methacrylate and 2-(perfluorooctyl)ethyl methacrylate, posing certain hazardous risks and failing to meet increasingly stringent environmental protection requirements.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The first objective of this invention is to provide an environmentally friendly heat-insulating automotive paint protection film. The environmentally friendly heat-insulating automotive paint protection film provided by this invention has the advantages of high light transmittance, good heat insulation performance, good UV resistance, good extensibility, and environmental friendliness.

[0008] The second objective of this invention is to provide a method for preparing an environmentally friendly heat-insulating automotive paint protection film.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] In a first aspect, the present invention provides an environmentally friendly heat-insulating automotive paint protection film, comprising, from top to bottom, a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film;

[0011] The heat insulation coating comprises the following raw materials in parts by weight: 100 parts of waterborne polyurethane resin emulsion, 15-25 parts of fatty acid ester modified heat insulation composite, 1-2 parts of ultraviolet absorber, and 5-8 parts of additives.

[0012] The thermal insulation composite comprises glass fiber powder, hollow glass microspheres, and nano-rare earth oxides.

[0013] Furthermore, the aqueous polyurethane resin emulsion is an anionic aqueous polyurethane resin emulsion.

[0014] Furthermore, the anionic aqueous polyurethane resin emulsion is AH-1605A from Anhui Anda Huatai New Materials Co., Ltd.

[0015] The above-mentioned anionic aqueous polyurethane resin emulsion forms a transparent film, which meets the transparency requirements of the environmentally friendly heat-insulating automotive paint protection film of this invention.

[0016] The heat-insulating composite is an inorganic material with poor compatibility with water-based polyurethane resin emulsions, making it prone to agglomeration. Direct addition not only leads to poor heat insulation and UV blocking performance of the environmentally friendly heat-insulating automotive paint protection film, but also affects its light transmittance and stretchability. Unlike automotive window film, automotive paint protection film needs to be applied to large areas and complex curved surfaces, requiring higher stretchability. The inventors discovered that modifying the heat-insulating composite with conventional silane coupling agents results in automotive paint protection films with poor heat insulation, light transmittance, and stretchability. However, using a fatty acid ester-modified heat-insulating composite can solve these problems. This is likely because long-chain fatty acids are grafted onto the hydroxyl groups of the heat-insulating composite through esterification, forming a soft interface layer. This not only improves the compatibility and dispersibility of the heat-insulating composite in the water-based polyurethane resin emulsion system, but also enhances the stretchability of the automotive paint protection film.

[0017] Furthermore, the mass ratio of the glass fiber powder, hollow glass microspheres, and nano-rare earth oxides is 1-2:7-8:1.

[0018] Furthermore, the glass fiber powder has a fiber diameter of 15-20µm and an aspect ratio of 10-12:1.

[0019] Furthermore, the hollow glass microspheres have a D50 of 5-10µm.

[0020] Hollow glass microspheres possess excellent heat insulation properties, while nano-rare earth oxides exhibit excellent UV blocking effects. The inventors discovered that when the heat insulation composite consists of hollow glass microspheres and nano-rare earth oxides, the resulting heat-insulating automotive paint protection film exhibits a significant decrease in ductility. To address this issue, and to prevent the added substances from affecting the film's light transmittance and heat insulation, the inventors attempted to add glass fiber powder or glass powder. However, adding glass powder proved ineffective; it not only failed to solve the ductility problem but also led to a significant decrease in both heat insulation and light transmittance. Adding glass fiber powder, on the other hand, not only solved the ductility problem but also... While it can address the issue of heat insulation, it can also improve thermal insulation to some extent. This may be due to the fiber reinforcement mechanism of glass fiber powder and the fact that its interwoven fiber structure can form a heat insulation layer, achieving synergistic heat insulation with hollow glass microspheres. However, not all glass fiber powders can solve the problem of ductility without affecting light transmittance, heat insulation, and ultraviolet blocking properties. When the fiber diameter and aspect ratio of the glass fiber powder are too small, the heat insulation effect will actually decrease. In addition, the mass ratio of glass fiber powder, hollow glass microspheres, and nano-rare earth oxides is also crucial, affecting the heat insulation, light transmittance, and ductility of the protective film.

[0021] Furthermore, the nano-rare earth oxide is nano-cerium oxide and nano-lanthanum oxide in a mass ratio of 4-6:1.

[0022] Furthermore, the particle size of the nano-cerium oxide is 40-60 nm.

[0023] Furthermore, the particle size of the nano-lanthanum oxide is 50-80 nm.

[0024] The inventors discovered that when the nano-rare earth oxides are nano-cerium oxide and nano-lanthanum oxide in a mass ratio of 4-6:1, the resulting heat-insulating automotive paint protection film has both good ultraviolet blocking properties and good light transmittance.

[0025] Furthermore, the preparation method of the fatty acid ester modified heat-insulating composite includes the following steps:

[0026] Hydroxylated thermal insulation compound, C 12 -C 18 The fatty acids and anhydrous ethanol are mixed, heated under reflux with stirring, centrifuged, washed, and dried to obtain the final product.

[0027] Furthermore, the C 12 -C 18 The fatty acid is selected from at least one of lauric acid, myristic acid, palmitic acid and stearic acid.

[0028] Furthermore, the hydroxylated heat-insulating composite, C 12 -C 18 The mass ratio of fatty acids to anhydrous ethanol is 1-2:1-2:20-30.

[0029] Furthermore, the heating and stirring temperature is 78-82℃, and the time is 3-6 hours.

[0030] Furthermore, the hydroxylated thermal insulation composite is modified by hydroxylating the thermal insulation composite with sodium hydroxide solution.

[0031] Furthermore, the preparation method of the hydroxylated heat-insulating composite includes the following steps:

[0032] Rare earth oxides are immersed in sodium hydroxide solution and kept at 50-70℃ for 10-12 hours. After filtration, washing, and drying, the product is obtained.

[0033] Glass fiber powder and hollow glass microspheres are immersed in sodium hydroxide solution and kept at 50-70℃ for 1-3 hours. After filtration, washing and drying, the product is obtained.

[0034] Furthermore, the mass concentration of the sodium hydroxide solution is 20-30%.

[0035] Furthermore, the ultraviolet absorber is a mixture of benzotriazole ultraviolet absorbers and hindered amine light stabilizers.

[0036] Furthermore, the ultraviolet absorber is ultraviolet absorber UV-5151.

[0037] Furthermore, the additives include leveling agents, defoamers, wetting agents, and thickeners.

[0038] Furthermore, the mass ratio of the leveling agent, defoamer, wetting agent, and thickener is 1-2:1-2:1-2:1-2.

[0039] Furthermore, the wetting agent is a siloxane-based twin-structure surfactant.

[0040] Furthermore, the defoamer is selected from at least one of silicone defoamers and polymer defoamers.

[0041] Further, the leveling agent is a polyether-modified polysiloxane. Further, the thickener is selected from at least one of hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl ethyl cellulose.

[0042] Furthermore, the method for preparing the heat-insulating coating includes the following steps: stirring an aqueous polyurethane resin emulsion, a fatty acid ester modified heat-insulating composite, an ultraviolet absorber, and an additive until homogeneous.

[0043] Furthermore, the protective film is a PET film.

[0044] Furthermore, the first TPU substrate and the second TPU substrate are transparent aliphatic TPU films.

[0045] Furthermore, the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive.

[0046] Furthermore, the release film is a PET release film.

[0047] Furthermore, the thickness of the protective film is 20-30µm.

[0048] Furthermore, the thickness of the self-healing layer is 5-15µm.

[0049] Furthermore, the thickness of the first TPU substrate and the second TPU substrate is 100-200µm.

[0050] Furthermore, the thickness of the heat-insulating coating is 5-15µm.

[0051] Furthermore, the thickness of the pressure-sensitive adhesive layer is 15-35µm.

[0052] Furthermore, the thickness of the release film is 20-30µm.

[0053] Furthermore, the coating used for the self-cleaning coating is ZS-511 nano self-cleaning coating from Beijing Zhisheng Weihua Chemical Co., Ltd.

[0054] Secondly, the present invention provides a method for preparing the above-mentioned environmentally friendly heat-insulating automotive paint protection film, comprising the following steps: coating a heat-insulating coating and a pressure-sensitive adhesive layer on the surface of a second TPU substrate, and after drying, laminating both sides with a first TPU substrate and a release film respectively; coating a self-cleaning coating on the surface of the first TPU substrate, and after drying, laminating it with a protective film to obtain the final product.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] 1. The present invention uses a fatty acid ester modified heat insulation compound to improve the heat insulation, light transmittance and extensibility of automotive paint protection film.

[0057] 2. The present invention uses glass fiber powder, hollow glass microspheres and nano rare earth oxides as thermal insulation composite. In particular, the addition of glass fiber powder can not only solve the problem of ductility, but also improve the thermal insulation to a certain extent.

[0058] 3. This invention controls the mass ratio of glass fiber powder, hollow glass microspheres, and nano-rare earth oxides to achieve the optimal overall performance of the environmentally friendly heat-insulating automotive paint protection film.

[0059] 4. When nano-cerium oxide and nano-lanthanum oxide are used as nano-rare earth oxides in this invention, the resulting heat-insulating automotive paint protection film has good ultraviolet blocking properties while also having good light transmittance. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the structure of the environmentally friendly heat-insulating automotive paint protection film in Example 2;

[0061] Figure 2 This is a physical image of the environmentally friendly heat-insulating automotive paint protection film of Example 2. Detailed Implementation

[0062] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0063] Unless otherwise specified, the raw materials, reagents or apparatus used in the following examples and comparative examples are available from conventional commercial sources or can be obtained by existing known methods.

[0064] Example 1 An environmentally friendly heat-insulating automotive paint protection film, comprising, from top to bottom, a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film;

[0065] The protective film is a PET film with a thickness of 25µm.

[0066] The self-cleaning coating used is ZS-511 nano self-cleaning coating from Beijing Zhisheng Weihua Chemical Co., Ltd., with a thickness of 10µm.

[0067] The first TPU substrate and the second TPU substrate are transparent aliphatic TPU films with a thickness of 100µm, manufactured by Xingen Environmental Protection Technology (Shenzhen) Co., Ltd.

[0068] The heat-insulating coating comprises the following raw materials in parts by weight: 100 parts of waterborne polyurethane resin emulsion, 15 parts of fatty acid ester modified heat-insulating composite, 1 part of ultraviolet absorber, and 5 parts of additives.

[0069] The aqueous polyurethane resin emulsion is an anionic aqueous polyurethane resin emulsion, specifically AH-1605A from Anhui Anda Huatai New Materials Co., Ltd.

[0070] The thermal insulation composite consists of glass fiber powder, hollow glass microspheres, and nano-rare earth oxides in a mass ratio of 2:7:1.

[0071] The glass fiber powder has a fiber diameter of 16µm and an aspect ratio of 11:1. (Shenzhen Xinhai Technology Co., Ltd.)

[0072] The hollow glass microspheres have a D50 of 5µm and are manufactured by Zhengzhou Shenglait Hollow Microsphere New Material Co., Ltd. The standard size is HM10.

[0073] The nano-rare earth oxides are nano-cerium oxide and nano-lanthanum oxide in a mass ratio of 5:1.

[0074] The lanthanum oxide nanoparticles have a particle size of 80 nm and are manufactured by Ningbo Luofei Nanotechnology Co., Ltd.

[0075] The cerium oxide nanoparticles have a particle size of 40 nm, according to Ningbo Luofei Nanotechnology Co., Ltd.

[0076] The preparation method of the fatty acid ester modified heat-insulating composite includes the following steps:

[0077] Hydroxylated thermal insulation compound, C 12 -C 18 The fatty acids and anhydrous ethanol are mixed, heated under reflux at 80°C for 5 hours, centrifuged, washed, and dried to obtain the final product.

[0078] The C 12 -C 18 The fatty acid is lauric acid.

[0079] The hydroxylated heat-insulating compound, C 12 -C 18 The mass ratio of fatty acids to anhydrous ethanol is 1.5:1.5:30.

[0080] The preparation method of the hydroxylated heat-insulating composite includes the following steps:

[0081] Rare earth oxides are immersed in sodium hydroxide solution and kept at 60°C for 12 hours. After filtration, washing, and drying, the product is obtained.

[0082] Glass fiber powder and hollow glass microspheres are immersed in sodium hydroxide solution and kept at 60°C for 2 hours. After filtration, washing, and drying, the product is obtained.

[0083] The sodium hydroxide solution has a mass concentration of 30%.

[0084] The ultraviolet absorber is ultraviolet absorber UV-5151.

[0085] The additives are leveling agents, defoamers, wetting agents, and thickeners in a mass ratio of 1:1:1:2.

[0086] The wetting agent is a siloxane-based twin structure surfactant, TEGO® Twin 4100.

[0087] The defoamer is a polymeric defoamer, TEGO Foamex 830.

[0088] The leveling agent is a polyether-modified polysiloxane, TEGO Glide 410.

[0089] The thickener is hydroxymethyl cellulose.

[0090] The method for preparing the heat-insulating coating includes the following steps: stirring waterborne polyurethane resin emulsion, fatty acid ester modified heat-insulating composite, ultraviolet absorber and additives evenly to obtain the coating.

[0091] The thickness of the heat insulation coating is 10µm.

[0092] The pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive with a thickness of 30µm, namely Henkel LOCTITE DURO-TAK 8087HS.

[0093] The release film is a PET release film with a thickness of 30µm.

[0094] The above-mentioned method for preparing an environmentally friendly heat-insulating automotive paint protection film includes the following steps: applying a heat-insulating coating and a pressure-sensitive adhesive layer to the surface of a second TPU substrate, drying them, and then laminating them on both sides to a first TPU substrate and a release film; applying a self-cleaning coating to the surface of the first TPU substrate, drying them, and then laminating them with a protective film to obtain the final product.

[0095] Example 2 An environmentally friendly heat-insulating automotive paint protection film, comprising, from top to bottom, a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film;

[0096] The only difference from Example 1 is the heat insulation coating, which comprises the following raw materials in parts by weight: 100 parts of waterborne polyurethane resin emulsion, 20 parts of fatty acid ester modified heat insulation composite, 1.5 parts of ultraviolet absorber, and 6 parts of additives; the rest are the same.

[0097] Example 3 An environmentally friendly heat-insulating automotive paint protection film, comprising, from top to bottom, a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film;

[0098] The only difference from Example 1 is the heat insulation coating, which comprises the following raw materials in parts by weight: 100 parts of waterborne polyurethane resin emulsion, 25 parts of fatty acid ester modified heat insulation composite, 2 parts of ultraviolet absorber, and 8 parts of additives; all other components are the same.

[0099] Comparative Example 1: An environmentally friendly heat-insulating automotive paint protection film, comprising, from top to bottom, a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film;

[0100] The only difference from Example 2 is the heat insulation coating, in which the fatty acid ester modified heat insulation composite is replaced with an equal mass of silane coupling agent KH550 modified heat insulation composite.

[0101] The preparation method of the thermal insulation composite modified by the silane coupling agent KH550 includes the following steps:

[0102] Mix silane coupling agent KH550 with a 75% (v / v) aqueous ethanol solution, adjust the pH to 4, hydrolyze for 1 h, add the hydroxylated heat-insulating complex, stir for 5 h, centrifuge, wash, and dry to obtain the final product.

[0103] The mass ratio of the hydroxylated heat-insulating composite, the silane coupling agent KH550, and the ethanol aqueous solution is 1.5:4.5:50; all other components are the same.

[0104] Comparative Example 2: An environmentally friendly heat-insulating automotive paint protection film, comprising, from top to bottom, a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film;

[0105] The only difference from Example 2 is the heat insulation coating. In the heat insulation coating, the glass fiber powder is replaced with an equal mass of hollow glass microspheres. That is, the heat insulation composite is hollow glass microspheres and nano rare earth oxides in a mass ratio of 9:1; everything else is the same.

[0106] Comparative Example 3: An environmentally friendly heat-insulating automotive paint protection film, comprising, from top to bottom, a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film;

[0107] The only difference from Example 2 is the heat insulation coating. In the heat insulation coating, the glass fiber powder has a fiber diameter of 13µm and an aspect ratio of 6:1. (Suzhou Qiuyi New Materials Co., Ltd.)

[0108] Comparative Example 4: An environmentally friendly heat-insulating automotive paint protection film, comprising, from top to bottom, a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film;

[0109] The only difference from Example 2 is the heat insulation coating, in which glass fiber powder is replaced with an equal mass of glass powder; the average particle size of the glass powder is 4µm, manufactured by Guangdong Yuanlei Powder Co., Ltd.; all other aspects are the same.

[0110] Comparative Example 5: An environmentally friendly heat-insulating automotive paint protection film, comprising, from top to bottom, a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film;

[0111] The only difference from Example 2 is the heat insulation coating. In the heat insulation coating, the nano-rare earth oxides are nano-cerium oxide and nano-zirconia in a mass ratio of 5:1; the nano-zirconia has a particle size of 80nm and is manufactured by Yumu (Ningbo) New Materials Co., Ltd.; all other aspects are the same.

[0112] Comparative Example 6

[0113] An environmentally friendly heat-insulating automotive paint protection film, comprising, from top to bottom, a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film;

[0114] The only difference from Example 2 is the heat insulation coating, in which the mass ratio of glass fiber powder, hollow glass microspheres and nano-rare earth oxides is 1:6:3; all other aspects are the same.

[0115] I. Performance Testing

[0116] Performance Test 1

[0117] Thermal insulation and ultraviolet blocking performance: The transmittance was measured in the wavelength range of 750nm-2500nm using a spectral analysis instrument to calculate the infrared blocking rate; the transmittance was measured in the wavelength range of 280nm-400nm to calculate the ultraviolet blocking rate.

[0118] Performance Test 2

[0119] Light transmittance: Light transmittance was tested according to GB / T 2410-2008.

[0120] Performance Test 3

[0121] Elongation at break: The elongation at break was tested according to GB / T 1040.1-2025, with a tensile speed of 100 mm / min.

[0122] II. Performance Test Results

[0123] Table 1

[0124]

[0125] As can be seen from Table 1:

[0126] The heat-insulating coatings in Examples 1-3 use the fatty acid ester modified heat-insulating composite material for which the present invention is claimed, resulting in an environmentally friendly heat-insulating automotive paint protection film with good heat insulation, ultraviolet blocking, light transmittance, and ductility.

[0127] The heat insulation composite modified with silane coupling agent KH550 in the heat insulation coating of Comparative Example 1 showed little change in the ultraviolet blocking properties of the environmentally friendly heat insulation automotive paint protection film, but the heat insulation, light transmittance and ductility decreased significantly.

[0128] In Comparative Example 2, replacing glass fiber powder with an equal mass of hollow glass microspheres in the heat insulation coating resulted in an environmentally friendly heat-insulating automotive paint protection film with minimal changes in heat insulation, UV blocking, and light transmittance, but a significant decrease in ductility.

[0129] The fiber diameter and aspect ratio of the glass fiber powder in the heat insulation coating of Comparative Example 3 are not within the scope of protection of this invention. The light transmittance and ductility of the resulting environmentally friendly heat insulation automotive paint protection film are relatively small, but the heat insulation and ultraviolet blocking properties are significantly reduced.

[0130] In Comparative Example 4, replacing glass fiber powder with an equal mass of glass powder in the heat insulation coating resulted in a small change in the UV blocking properties of the environmentally friendly heat insulation automotive paint protection film, but a significant decrease in heat insulation, light transmittance, and ductility.

[0131] The nano-rare earth oxides in the heat insulation coating of Comparative Example 5 are not within the scope of protection of this invention. The resulting environmentally friendly heat insulation automotive paint protection film has little change in extensibility and heat insulation properties, but its ultraviolet blocking and light transmittance are significantly reduced.

[0132] In Comparative Example 6, the mass ratio of glass fiber powder, hollow glass microspheres, and nano-rare earth oxides in the heat insulation coating is not within the scope of protection of this invention. The resulting environmentally friendly heat-insulating automotive paint protection film has a small change in ultraviolet blocking properties, but its heat insulation, light transmittance, and ductility are significantly reduced.

[0133] The environmental performance test results of the environmentally friendly heat-insulating automotive paint protection film of Example 2 are shown in Table 2 below. The test methods were as follows: referring to IEC 62321-4:2013+AMD1:2017, IEC 62321-5:2013, IEC 62321-7-2:2017 and IEC 62321-12:2023, the analysis was performed using ICP-OES / AAS, UV-Vis and GC-MS.

[0134] Table 2

[0135]

[0136] Note 1:

[0137] (1) 1 mg / kg = 1 ppm = 0.0001%.

[0138] (2) MDL = Method detection limit.

[0139] (3) ND = Not detected ( <MDL)。

[0140] (4) "-" = Not specified.

[0141] Note 2:

[0142] (1) The maximum permissible limit is referenced from RoHS Directive (EU) 2015 / 863.

[0143] (2) The IEC 62321 series is equivalent to the EN 62321 series.

[0144] (3) Starting July 22, 2021, restrictions on DEHP, BBP, DBP and DIBP apply to medical devices, including in vitro medical devices and monitoring instruments, including industrial monitoring and control instruments.

[0145] As can be seen from Table 2, the environmentally friendly heat-insulating automotive paint protection film provided by this invention complies with the environmental requirements of the EU RoHS Directive.

[0146] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. An environmentally friendly, heat-insulating automotive paint protection film, characterized in that, From top to bottom, it includes a protective film, a self-cleaning coating, a first TPU substrate, a heat-insulating coating, a second TPU substrate, a pressure-sensitive adhesive layer, and a release film; The heat insulation coating is composed of the following raw materials in parts by weight: 100 parts of water-based polyurethane resin emulsion, 15-25 parts of fatty acid ester modified heat insulation composite, 1-2 parts of ultraviolet absorber and 5-8 parts of additives. The thermal insulation composite is composed of glass fiber powder, hollow glass microspheres and nano-rare earth oxides in a mass ratio of 1-2:7-8:

1. The glass fiber powder has a fiber diameter of 15-20µm and an aspect ratio of 10-12:

1.

2. The environmentally friendly heat-insulating automotive paint protection film according to claim 1, characterized in that, The hollow glass microspheres have a D50 of 5-10µm.

3. The environmentally friendly heat-insulating automotive paint protection film according to claim 2, characterized in that, The nano-rare earth oxides are nano-cerium oxide and nano-lanthanum oxide in a mass ratio of 4-6:

1.

4. The environmentally friendly heat-insulating automotive paint protection film according to claim 3, characterized in that, The nano-cerium oxide has a particle size of 40-60 nm; the nano-lanthanum oxide has a particle size of 50-80 nm.

5. The environmentally friendly heat-insulating automotive paint protection film according to claim 1, characterized in that, The preparation method of the fatty acid ester modified heat-insulating composite includes the following steps: Hydroxylated thermal insulation compound, C 12 -C 18 The fatty acids and anhydrous ethanol are mixed, heated under reflux with stirring, centrifuged, washed, and dried to obtain the final product.

6. The environmentally friendly heat-insulating automotive paint protection film according to claim 5, characterized in that, The C 12 -C 18 The fatty acid is selected from at least one of lauric acid, myristic acid, palmitic acid and stearic acid.

7. The environmentally friendly heat-insulating automotive paint protection film according to claim 6, characterized in that, The hydroxylated thermal insulation composite is prepared by hydroxylating the thermal insulation composite with sodium hydroxide solution.

8. The environmentally friendly heat-insulating automotive paint protection film according to any one of claims 1-7, characterized in that, The additives include leveling agents, defoamers, wetting agents, and thickeners.

9. The method for preparing the environmentally friendly heat-insulating automotive paint protection film according to any one of claims 1-8, characterized in that, Includes the following steps: A heat-insulating coating and a pressure-sensitive adhesive layer are coated on the surface of the second TPU substrate, respectively. After drying, they are laminated to the first TPU substrate and the release film on both sides. A self-cleaning coating is coated on the surface of the first TPU substrate, and after drying, it is laminated to the protective film to obtain the final product.

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