A polyester-based explosion-proof thermal insulation composite film and a preparation method and application thereof

Abstract

The application belongs to the technical field of heat insulation films, and discloses a polyester-based explosion-proof heat insulation composite film and a preparation method and application thereof. The explosion-proof heat insulation composite film is a composite film with a layered structure. The layered structure comprises a sandwich heat insulation film, an anti-scratch layer and a mounting adhesive layer arranged on both sides of the sandwich heat insulation film. The sandwich heat insulation film is composed of a first polyester film, a second polyester film and a heat insulation layer sandwiched between the first polyester film and the second polyester film. In the heat insulation coating liquid, chlorinated polyolefin is used to increase the bonding adhesion and leveling dispersibility of the coating liquid on the polyester film, so that the coating type sandwich heat insulation film has excellent tear resistance and peeling resistance. The defects of the current coating type heat insulation film, such as easy blistering, heat insulation performance attenuation and reduced explosion-proof performance, are solved. The coating preparation process is simple and does not require a complex magnetron sputtering process, so that the cost of the explosion-proof heat insulation film is scaled and the production is realized.

Description

Technical Field

[0001] This invention belongs to the field of heat insulation film technology, and specifically relates to an explosion-proof and heat-insulating composite film with polyester as the substrate, its preparation method and application, which is used for automobile windows and has both heat insulation and explosion-proof functions. Background Technology

[0002] The main source of solar heat is near-infrared radiation (wavelength 760-1500nm). To reduce solar heat penetration through car windows, heat-insulating films, also known as "solar films," are needed. These films reduce the thermal effect of near-infrared radiation by reflecting or absorbing it. Current heat-insulating films primarily use PET polyester as the base film, forming an absorbing or reflecting coating on the substrate through techniques such as applying a heat-insulating coating or magnetron sputtering a metal layer, thus blocking infrared and ultraviolet radiation from the sun.

[0003] Chinese invention patent document CN104275889B discloses a high-performance nanocomposite heat insulation film and its preparation method, which is composed of a wear-resistant layer, a first PET layer, a magnetron sputtering layer, a nano heat insulation layer, a second PET layer, an mounting layer, and a release layer arranged in sequence. The heat insulation effect of the film is improved by absorbing infrared rays through nano-tungsten trioxide and reflecting infrared rays through a sputtered metal reflective layer.

[0004] Chinese invention patent document CN106313832B discloses a heat-insulating film and its preparation method, which disperses metal particles in an ultraviolet-curable adhesive to form a reflective layer; and mixes titanium dioxide with an adhesive to form an absorbent layer. This film can reflect some of the sunlight's energy and then absorb it, further enhancing its heat insulation function and reducing the reflectivity issues of a completely metallic layer.

[0005] Chinese invention patent document CN106956486B discloses a heat-insulating film with high ultraviolet blocking performance and its preparation method. The ultraviolet absorbing coating is applied to any side of the first base film by micro-gravure coating. After the coating is dried, it is combined with any side of the second base film to form an ultraviolet absorbing composite film.

[0006] Currently, magnetron sputtered metal reflective layers are the most effective heat insulation films due to their significant infrared reflection. Furthermore, their dense interlayer structure and strong bonding prevent delamination and peeling, effectively enhancing the explosion-proof performance of the heat insulation film. Therefore, most explosion-proof heat insulation films currently available utilize magnetron sputtered metal layers. However, magnetron sputtered metal layers severely block electronic signals, causing significant interference with in-vehicle navigation and autonomous driving systems. Moreover, the equipment investment for manufacturing heat insulation films using magnetron sputtering is high, the maintenance of the magnetron sputtering vacuum system is complex, and the yield rate is low, making it unsuitable for low-cost, large-scale production.

[0007] Preparing heat insulation films by coating the insulation layer is a low-cost method that allows for the flexible application of materials with reflective and infrared absorption functions to the insulation layer via a coating liquid. It is also easy to mass-produce and is currently the mainstream technology for preparing heat insulation films. However, the coated insulation layer is prone to separation from the substrate, leading to interlayer delamination, blistering, and rapid aging of the insulation film. Under stress, it is easily torn and delaminated, resulting in a decreased ability to adhere to glass fragments and a significant reduction in its explosion-proof effect.

[0008] According to the industry standard QC / T 1170-2022 "Functional Films for Automotive Glass", protective heat-insulating films (GF type) have gradually been developed for automotive glass. These films not only require heat insulation but also a certain degree of explosion-proof capability. Therefore, the standard has increased the maximum tensile strength at break of the thickest 25mm heat-insulating film from 100N to 200N. To achieve explosion-proof functionality, coated explosion-proof heat-insulating films generally increase their thickness from 2.5mil to over 5.0mil. However, with increased film thickness, the application process becomes more difficult, and visible light transmittance decreases. Summary of the Invention

[0009] To address the shortcomings of current coated heat insulation films used in automotive windows, such as easy bubbling, reduced heat insulation performance, and decreased explosion-proof performance, this invention proposes an explosion-proof heat insulation composite film with polyester as the base material, its preparation method, and its application. By improving the interlayer adhesion between the heat insulation layer and the base film, a large number of hydrogen bond structures are formed, avoiding tearing and delamination of the layered heat insulation film, and significantly improving the explosion-proof performance of the heat insulation film.

[0010] To achieve the aforementioned technical effects, the specific technical solution adopted by the present invention is as follows:

[0011] First, an explosion-proof and heat-insulating composite film with polyester as the base material is provided. The explosion-proof and heat-insulating composite film is a composite film with a layered structure. The layered structure includes an interlayer heat-insulating film, an anti-scratch layer disposed on both sides of the interlayer heat-insulating film, and an installation adhesive layer. The interlayer heat-insulating film is composed of a first polyester film, a second polyester film, and a heat-insulating layer sandwiched between the first polyester film and the second polyester film.

[0012] The first polyester film and the second polyester film are biaxially oriented polyethylene terephthalate films with a thickness of 30-40 μm;

[0013] The thickness of the heat insulation layer is 6-10 μm, and it is coated with a heat insulation coating liquid prepared by heat insulation agent, ultraviolet absorber, methyl isobutyl ketone, chlorinated polyolefin, polyacrylate, and solvent in a mass ratio of (3-5):(0.6-1):(15-20):(1-2):(20-25):(50-60).

[0014] The anti-scratch layer has a thickness of 2.5-3.5μm and is formed by coating a wear-resistant coating liquid prepared by mixing hexafunctional polyurethane acrylate, acrylic modified polysiloxane, reactive diluent, and photoinitiator in a mass ratio of (30-40):(10-15):(40-50):(3-5).

[0015] The mounting adhesive layer is a pressure-sensitive adhesive with a coating thickness of 6-8 μm, which is obtained by dispersing liquid acrylate pressure-sensitive adhesive with ultraviolet absorber and silane coupling agent at a mass ratio of 100:(1-1.5):(1-2).

[0016] Preferably, the light transmittance of the first and second polyester films is >95%. Biaxially oriented polyethylene terephthalate (BOPET) film possesses high transparency and excellent strength, stiffness, and puncture resistance. Through biaxial stretching, the molecular chains are stably oriented, resulting in low thermal shrinkage and preventing the insulation film from wrinkling, deforming, or delaminating under high-temperature exposure.

[0017] Preferably, the heat insulation agent is at least one of nano-tungsten oxide powder, nano-antimony tin oxide powder, nano-indium tin oxide powder, and nano-cesium tungsten bronze powder with a particle size of 20-50 nm. When the heat insulation agent is dispersed in the coating liquid in the form of discrete fine particles, this type of heat insulation agent has a good absorption effect on infrared rays.

[0018] Preferably, the chlorinated polyolefin is an acid-modified chlorinated polyolefin. Chlorinated polyolefins introduce abundant polar chlorine groups, exhibiting good wetting and dispersibility with the heat insulation agent. In particular, the acid-modified chlorinated polyolefin, when dissolved in methyl isobutyl ketone, increases the adhesion and leveling properties of the coating liquid on the polyester film, enhances the toughness of the heat insulation film, and effectively absorbs and disperses impact energy when subjected to external impacts, thereby improving the explosion-proof performance of the heat insulation film.

[0019] Preferably, the polyacrylate is polybutyl acrylate.

[0020] Preferably, the solvent is ethyl acetate.

[0021] Preferably, the mass ratio of the hexafunctional polyurethane acrylate to the acrylic-modified polysiloxane is 3:1. Through curing, the siloxane network is fully cross-linked, increasing the pencil hardness of the scratch-resistant layer to 5H or higher.

[0022] Preferably, the reactive diluent is selected from at least one of tripropylene glycol diacrylate and trimethylolpropane triacrylate.

[0023] Preferably, the photoinitiator is at least one of Irgacure184 and Irgacure369.

[0024] Preferably, the liquid acrylic pressure-sensitive adhesive uses Henkel's commercially available DURO-TAK® 109A as the pressure-sensitive adhesive base. It exhibits clear optical properties, resistance to heat and photo-aging, and strong adhesion, effectively adhering to glass fragments upon breakage to form a comprehensive explosion-proof protective barrier. When used as an installation adhesive, it generates high-strength adhesion simply by applying pressure with a scraper during application.

[0025] Preferably, the mounting adhesive layer is protected by a release film, which is a conventional BOPET release film with a surface low-energy treatment and a thickness of 10-20μm.

[0026] Preferably, the ultraviolet absorber is selected from at least one of UV-P and UV-327.

[0027] Furthermore, a method for preparing the aforementioned explosion-proof and heat-insulating composite film with polyester as the substrate is provided, the specific steps of which are as follows:

[0028] S1. Chlorinated polyolefin and methyl isobutyl ketone are ground and dissolved in a sand mill according to the mass ratio, and then the heat insulation agent is added and ground and dispersed to obtain heat insulation paste; polyacrylate is dissolved in a solvent to form glue; heat insulation paste and ultraviolet absorber are added to glue and ultrasonically dispersed, filtered, and heat insulation coating liquid is obtained for later use;

[0029] S2. Disperse the hexafunctional polyurethane acrylate, acrylate-modified polysiloxane, reactive diluent, and photoinitiator by ultrasonication according to the mass ratio, filter, and obtain the wear-resistant coating liquid;

[0030] S3. The first polyester base film is unwound and subjected to double-sided corona treatment. The heat insulation coating liquid is evenly coated on one side of the first polyester base film through a slit coating device, and then sent into a drying oven for baking.

[0031] S4. The second polyester base film is unwound and subjected to double-sided corona treatment, then attached to the heat insulation coating side after baking in step S3, and hot-pressed to obtain a sandwich heat insulation film.

[0032] S5. A wear-resistant coating liquid is applied to the first polyester base film surface of the interlayer heat insulation film, and a scratch-resistant layer is formed by UV curing; a pressure-sensitive adhesive is applied to the second polyester base film surface of the interlayer heat insulation film, and a mounting adhesive layer is formed by drying in an oven tunnel. A release film is then attached for protection, the edges are trimmed, and the film is rolled up to obtain an explosion-proof heat insulation composite film with polyester as the base material.

[0033] Preferably, the filtration in steps S1 and S2 uses an 800-mesh filter for vacuum filtration.

[0034] Preferably, the corona treatment in steps S3 and S4 increases the surface energy of the polyester film to over 50 mN / m. This corona treatment ensures a strong chemical bond between the heat-insulating coating liquid and the substrate, preventing film peeling upon impact and further improving the explosion-proof performance of the heat-insulating film.

[0035] The present invention also provides the explosion-proof and heat-insulating composite film based on the polyester substrate for the explosion-proof and heat-insulating application of automotive window glass.

[0036] Compared with the prior art, the outstanding features and significant progress of this invention are as follows:

[0037] 1. The explosion-proof and heat-insulating composite film based on polyester of the present invention has excellent tear resistance and delamination resistance through a multi-layer structure design of scratch-resistant layer, tough heat-insulating coating liquid and high-adhesion pressure-sensitive adhesive. This solves the defects of current coated heat-insulating films used in automobile windows, such as easy bubbling, heat insulation performance degradation and explosion-proof performance reduction.

[0038] 2. This invention uses chlorinated polyolefin in the heat-insulating coating liquid, which increases the bonding adhesion, leveling, and dispersibility of the coating liquid on the polyester film, enhances the tear resistance of the heat-insulating film, and effectively absorbs and disperses impact energy when subjected to external impacts, preventing film peeling and achieving an explosion-proof effect.

[0039] 3. The installation adhesive layer of the present invention uses a composite pressure-sensitive adhesive of acrylic pressure-sensitive adhesive, ultraviolet absorber, and silane coupling agent, which enhances the adhesion and aging resistance of the heat insulation film to the glass. It can adhere glass fragments to the film through adhesive action to prevent splashing.

[0040] 4. This invention achieves explosion-proof effect with a relatively low film thickness, and the coating preparation process is simple, requiring no complex magnetron sputtering process, thus realizing low-cost, large-scale coating production of explosion-proof and heat-insulating films. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of an explosion-proof and heat-insulating composite film with polyester as the substrate.

[0042] The markings in the attached diagram are as follows: 1-interlayer heat insulation film, 2-scratch-resistant layer, 3-installation adhesive layer, 101-first polyester film, 102-second polyester film, 103-heat insulation layer. Detailed Implementation

[0043] The following examples are intended to further describe the implementation process of the technical content of the present invention, rather than to limit the scope of protection of the claims of the present invention. Unless otherwise specified in the examples, all are conventional raw material or process conditions that can be understood by those skilled in the art.

[0044] Partial ingredient descriptions:

[0045] First polyester-based film: Biaxially oriented PET optical film, light transmittance 98%, haze 0.5%, thickness 40μm, Guangdong Chaolai Chaofu Technology Co., Ltd.

[0046] Second polyester base film: Biaxially oriented PET optical film, light transmittance 98%, haze 0.5%, thickness 30μm, Guangdong Chaolai Chaofu Technology Co., Ltd.

[0047] Release film: Fluorine-modified BOPET release film, 20μm thick, Guangdong Chaolai Chaofu Technology Co., Ltd.

[0048] Hexafunctional polyurethane acrylate: UV resin P-611, Guangzhou Zhongtuli New Material Technology Co., Ltd.

[0049] Acid-modified chlorinated polyolefin resin: YURON CP-300, chlorine content 30%, Ningbo Haoxin Yulong New Materials Co., Ltd.

[0050] Pressure-sensitive adhesive: DURO-TAK® 109A, Henkel, Germany.

[0051] This invention discloses an explosion-proof and heat-insulating composite film with polyester as the substrate, as shown in the attached figure. Figure 1 The explosion-proof and heat-insulating composite film is a composite film with a layered structure; the layered structure includes a sandwiched heat-insulating film 1, scratch-resistant layers 2 disposed on both sides of the sandwiched heat-insulating film 1, and an adhesive layer 3; the sandwiched heat-insulating film 1 is composed of a first polyester film 101, a second polyester film 102, and a heat-insulating layer 103 sandwiched between the first polyester film 101 and the second polyester film 102. The specific implementation is as follows:

[0052] Example 1

[0053] S1. Dissolve 0.1 kg of acid-modified chlorinated polyolefin resin (YURON CP-300, Ningbo Haoxin Yulong New Material Co., Ltd.) and 1.8 kg of methyl isobutyl ketone in a sand mill for 60 min. Then add 0.3 kg of nano-cesium tungsten bronze heat insulation agent (50 nm) and continue grinding and dispersing for 30 min to obtain heat insulation paste. Dissolve 2 kg of polybutyl acrylate in 5.5 kg of ethyl acetate to form glue. Add the heat insulation paste and 0.08 kg of ultraviolet absorber UV-P to the glue and ultrasonically disperse for 25 min. Vacuum filter using an 800-mesh filter to obtain heat insulation coating liquid for later use.

[0054] S2. Disperse 3 kg of hexafunctional polyurethane acrylate (UV resin P-611, Guangzhou Zhongtuli New Material Technology Co., Ltd.), 1 kg of acrylic acid modified polysiloxane (SA818C, Shanghai Huarong Chemical Co., Ltd.), 4 kg of reactive diluent tripropylene glycol diacrylate, and 0.3 kg of photoinitiator Irgacure184 ultrasonically for 20 min, and then vacuum filter using an 800-mesh filter to obtain the wear-resistant coating liquid;

[0055] S3. The first polyester base film is unwound and subjected to double-sided corona treatment to increase the surface energy of the base film to more than 50mN / m. The heat insulation coating liquid is evenly coated on one side of the first polyester base film through a slit coating device with a coating thickness of 8μm. Then it is sent into a drying oven to bake at 80℃.

[0056] S4. The second polyester base film is unwound and subjected to double-sided corona treatment to increase the surface energy of the base film to more than 50mN / m. It is then attached to the heat insulation coating side after baking in step S3 and hot-pressed at 100°C to obtain a sandwich heat insulation film.

[0057] S5. A wear-resistant coating liquid is applied to the first polyester base film surface of the sandwich heat insulation film with a coating thickness of 3.5μm, and then cured with ultraviolet light to form a scratch-resistant layer; a pressure-sensitive adhesive is prepared by stirring and dispersing pressure-sensitive adhesive with ultraviolet absorber UV-327 and silane coupling agent KH-560 at a mass ratio of 100:1:1.5. The pressure-sensitive adhesive is then applied to the second polyester base film surface of the sandwich heat insulation film with a coating thickness of 8μm. After drying in an oven tunnel, an installation adhesive layer is formed. A release film is then attached for protection, the edges are trimmed, and the film is rolled up to obtain an explosion-proof heat insulation composite film with polyester as the base material.

[0058] Example 2

[0059] S1. Dissolve 0.2 kg of acid-modified chlorinated polyolefin resin (YURON CP-300, Ningbo Haoxin Yulong New Material Co., Ltd.) and 2.0 kg of methyl isobutyl ketone in a sand mill for 60 min. Then add 0.4 kg of nano-tin antimony oxide heat insulation agent (20 nm) and continue grinding and dispersing for 30 min to obtain heat insulation paste. Dissolve 2 kg of polybutyl acrylate in 6.0 kg of ethyl acetate to form glue. Add the heat insulation paste and 0.1 kg of ultraviolet absorber UV-327 to the glue and ultrasonically disperse for 35 min. Vacuum filter using an 800-mesh filter to obtain heat insulation coating liquid for later use.

[0060] S2. Disperse 3 kg of hexafunctional polyurethane acrylate (UV resin P-611, Guangzhou Zhongtuli New Material Technology Co., Ltd.), 1.5 kg of acrylic modified polysiloxane (SA818C, Shanghai Huarong Chemical Co., Ltd.), 5 kg of reactive diluent trimethylolpropane triacrylate, and 0.3 kg of photoinitiator Irgacure369 by ultrasonication for 20 min, and then vacuum filter them using an 800-mesh filter to obtain the wear-resistant coating liquid.

[0061] S3. The first polyester base film is unwound and subjected to double-sided corona treatment to increase the surface energy of the base film to more than 50mN / m. The heat insulation coating liquid is evenly coated on one side of the first polyester base film through a slit coating device with a coating thickness of 10μm. Then it is sent into a drying oven to bake at 80℃.

[0062] S4. The second polyester base film is unwound and subjected to double-sided corona treatment to increase the surface energy of the base film to more than 50mN / m. It is then attached to the heat insulation coating side after baking in step S3 and hot-pressed at 100°C to obtain a sandwich heat insulation film.

[0063] S5. A wear-resistant coating liquid is applied to the first polyester base film surface of the sandwich heat insulation film with a coating thickness of 3μm, and then cured with ultraviolet light to form a scratch-resistant layer; pressure-sensitive adhesive is prepared by stirring and dispersing pressure-sensitive adhesive with ultraviolet absorber UV-327 and silane coupling agent KH-560 at a mass ratio of 100:1.5:2, and then applied to the second polyester base film surface of the sandwich heat insulation film with a coating thickness of 6μm. After drying in an oven tunnel, an installation adhesive layer is formed, a release film is attached for protection, the edges are trimmed, and the film is rolled up to obtain an explosion-proof heat insulation composite film with polyester as the base material.

[0064] Comparative Example 1

[0065] 1.8 kg of methyl isobutyl ketone and 0.3 kg of nano-cesium tungsten bronze heat insulation agent (50 nm) were ground and dispersed in a sand mill for 30 min to obtain a heat insulation slurry; 2 kg of polybutyl acrylate was dissolved in 5.5 kg of ethyl acetate to form an adhesive; the heat insulation slurry and 0.08 kg of ultraviolet absorber UV-P were added to the adhesive and ultrasonically dispersed for 25 min, and then vacuum filtered through an 800-mesh filter to obtain a heat insulation coating liquid for later use. The remaining preparation steps are the same as in Example 1.

[0066] This comparative example did not use acid-modified chlorinated polyolefin resin in the heat insulation coating liquid, but was otherwise identical to Example 1.

[0067] Comparative Example 2

[0068] The pressure-sensitive adhesive in this comparative example did not contain any ultraviolet absorbers or silane coupling agents; it used a pressure-sensitive base adhesive directly. Everything else was identical to that in Example 1.

[0069] Referring to the technical requirements and test methods of industry standard QC / T 1170-2022 "Functional Films for Automotive Glass", the infrared rejection ratio (IRR) of the heat insulation film at 940nm and 1400nm was tested; the total solar infrared heat rejection ratio (r) was also tested. IR Total Solar Power Rejection (TSER). The visible light transmittance (VLT), ultraviolet light rejection (UVR), and solar transmittance (ST) of the heat insulation film were tested according to the technical requirements and test methods of GA / T 744-2013 "Automotive Window Glass Sunshade Film". The results are shown in Table 1.

[0070] Table 1

[0071]

[0072] Referring to the technical requirements and test methods of industry standard QC / T 1170-2022 "Functional Films for Automotive Glass", the tensile strength and elongation at break of the heat insulation film at 25mm were tested; the adhesion strength of the film at 25mm on the glass was also tested; and the peel strength between the base film and the heat insulation coating was tested. The results are shown in Table 2.

[0073] Table 2

[0074]

[0075] The aging resistance of the heat insulation film was tested according to industry standard QC / T 1170-2022 "Functional Films for Automotive Glass". The heat insulation film was applied to the glass and aged under xenon arc lamp irradiation for 600 hours, with an irradiation range of 300nm-400nm and an irradiance of 110W / m. 2 The visible light transmittance, infrared blocking rate, and adhesion strength to the glass (25 mm) of the membrane were tested after aging; the peel strength between the base film and the heat insulation coating was also tested. The performance changes of the heat insulation film before and after light aging are compared, and the results are shown in Table 3.

[0076] Table 3

[0077]

[0078] Based on the above test results, the explosion-proof heat insulation film of the present invention has excellent infrared blocking effect, high adhesion strength, and high peel strength between the base film and the heat insulation coating. By enhancing the adhesion strength and the peel strength between the base film and the heat insulation coating, the heat insulation film is tough and not easy to delaminate. In the event of an impact, broken glass is less likely to tear the heat insulation film, effectively preventing splashing and improving the safety and explosion-proof effect.

[0079] As shown in Table 2, Comparative Example 1 did not use acid-modified chlorinated polyolefin resin in the insulation layer, resulting in a significant decrease in the peel strength between the base film and the insulation coating; Comparative Example 2's pressure-sensitive adhesive did not contain a silane coupling agent, leading to a significant decrease in the adhesion strength. The impact of this on the explosion-proof properties of the insulation film is obvious.

[0080] As shown in Table 3, after 600 hours of aging, the heat insulation film still maintains good visible light transmittance and infrared blocking rate, retaining excellent heat insulation performance, and no significant yellowing affecting visible light transmission is observed. Adhesion strength and laminated glass strength do not show significant attenuation due to photoaging. In contrast, Comparative Example 1, which did not use acid-modified chlorinated polyolefin resin in the heat insulation layer, experienced faster chemical structure damage to the adhesive layer during photoaging; the peel strength between the base film and the heat insulation coating decreased significantly. Comparative Example 2, which did not include UV absorbers in its pressure-sensitive adhesive, experienced rapid aging of the adhesive layer and a significant decrease in adhesion strength.

[0081] The explosion-proof and heat-insulating film of this invention exhibits significant heat insulation and explosion-proof effects when applied to vehicle windows. It overcomes the shortcomings of current coated heat-insulating films, such as unstable adhesive layer adhesion, easy bubbling, and lack of explosion-proof properties. Obviously, this invention is not limited to the detailed preparation process described above. Under the premise of understanding the technical concept of this invention, any equivalent substitutions of the raw materials for the product of this invention by those skilled in the art fall within the protection and disclosure scope of this invention.

Claims

1. A polyester-based explosion-proof and heat-insulating composite film, characterized in that, The explosion-proof and heat-insulating composite film is a composite film with a layered structure; the layered structure includes an interlayer heat-insulating film, an anti-scratch layer disposed on both sides of the interlayer heat-insulating film, and an installation adhesive layer; the interlayer heat-insulating film is composed of a first polyester film, a second polyester film, and a heat-insulating layer sandwiched between the first polyester film and the second polyester film; The first polyester film and the second polyester film are biaxially oriented polyethylene terephthalate films with a thickness of 30-40 μm; The thickness of the heat insulation layer is 6-10 μm, and it is coated with a heat insulation coating liquid prepared by heat insulation agent, ultraviolet absorber, methyl isobutyl ketone, chlorinated polyolefin, polyacrylate, and solvent in a mass ratio of (3-5):(0.6-1):(15-20):(1-2):(20-25):(50-60). The anti-scratch layer has a thickness of 2.5-3.5μm and is formed by coating a wear-resistant coating liquid prepared by mixing hexafunctional polyurethane acrylate, acrylic modified polysiloxane, reactive diluent, and photoinitiator in a mass ratio of (30-40):(10-15):(40-50):(3-5). The mounting adhesive layer is a pressure-sensitive adhesive with a coating thickness of 6-8 μm, which is obtained by dispersing liquid acrylate pressure-sensitive adhesive with ultraviolet absorber and silane coupling agent at a mass ratio of 100:(1-1.5):(1-2).

2. The explosion-proof and heat-insulating composite film with polyester as the substrate according to claim 1, characterized in that, The light transmittance of the first polyester film and the second polyester film is >95%.

3. The explosion-proof and heat-insulating composite film with polyester as the substrate according to claim 1, characterized in that, The heat insulation agent is at least one of nano-tungsten oxide powder, nano-antimony tin oxide powder, nano-indium tin oxide powder, and nano-cesium tungsten bronze powder with a particle size of 20-50 nm.

4. The explosion-proof and heat-insulating composite film with polyester as the substrate according to claim 1, characterized in that, The chlorinated polyolefin is selected from acid-modified chlorinated polyolefins.

5. The explosion-proof and heat-insulating composite film with polyester as the substrate according to claim 1, characterized in that, The polyacrylate is selected from polybutyl acrylate; the solvent is selected from ethyl acetate.

6. The explosion-proof and heat-insulating composite film with polyester as the substrate according to claim 1, characterized in that, The active diluent is selected from at least one of tripropylene glycol diacrylate and trimethylolpropane triacrylate.

7. The explosion-proof and heat-insulating composite film with polyester as the substrate according to claim 1, characterized in that, The photoinitiator is selected from at least one of Irgacure184 and Irgacure369.

8. The explosion-proof and heat-insulating composite film with polyester as the substrate according to claim 1, characterized in that, The ultraviolet absorber is selected from at least one of UV-P and UV-327.

9. A method for preparing an explosion-proof and heat-insulating composite film with polyester as the substrate as described in any one of claims 1-8, characterized in that, The specific steps include: S1. Chlorinated polyolefin and methyl isobutyl ketone are ground and dissolved in a sand mill according to the mass ratio, and then the heat insulation agent is added and ground and dispersed to obtain heat insulation paste; polyacrylate is dissolved in a solvent to form glue; heat insulation paste and ultraviolet absorber are added to glue and ultrasonically dispersed, filtered, and heat insulation coating liquid is obtained for later use; S2. Disperse the hexafunctional polyurethane acrylate, acrylate-modified polysiloxane, reactive diluent, and photoinitiator by ultrasonication according to the mass ratio, filter, and obtain the wear-resistant coating liquid; S3. The first polyester base film is unwound and subjected to double-sided corona treatment. The heat insulation coating liquid is evenly coated on one side of the first polyester base film through a slit coating device, and then sent into a drying oven for baking. S4. The second polyester base film is unwound and subjected to double-sided corona treatment, then attached to the heat insulation coating side after baking in step S3, and hot-pressed to obtain a sandwich heat insulation film. S5. A wear-resistant coating liquid is applied to the first polyester base film surface of the interlayer heat insulation film, and a scratch-resistant layer is formed by UV curing; a pressure-sensitive adhesive is applied to the second polyester base film surface of the interlayer heat insulation film, and a mounting adhesive layer is formed by drying in an oven tunnel. A release film is then attached for protection, the edges are trimmed, and the film is rolled up to obtain an explosion-proof heat insulation composite film with polyester as the base material.

10. An explosion-proof and heat-insulating composite film based on polyester as described in any one of claims 1-8, applied to the explosion-proof and heat-insulating properties of automotive window glass.

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