Temperature-controlled adaptive in-situ self-healing residue-free protective film, its preparation method and application

Abstract

This invention relates to a temperature-controlled, adaptive, in-situ self-healing, residue-free protective film, its preparation method, and its applications. The film comprises a PET substrate layer, and, from top to bottom, a transparent hydrophobic layer with a moth-eye-like nanostructure, a thermochromic photothermal control layer, an in-situ self-healing layer, a low-adhesion, residue-free interface layer, and an adhesive layer, all stacked on the surface of the PET substrate layer. The protective film of this invention can achieve temperature adaptive regulation and operate stably within a temperature range of -20℃ to 60℃; it possesses in-situ self-healing capabilities, and scratches ≤50μm in depth can be completely repaired by irradiation with natural light or ordinary ultraviolet light for 1–5 minutes; it leaves no residue upon peeling, and its adhesion is controllable; it integrates multiple functions such as self-cleaning, acid and alkali resistance, and scratch resistance. The preparation process is simple, using conventional processing equipment and readily available raw materials.

Description

Technical Field

[0001] This invention relates to the field of protective film technology, specifically to a temperature-controlled adaptive in-situ self-healing residue-free protective film, its preparation method, and its application. Background Technology

[0002] Currently, protective films are widely used for surface protection of various products to prevent scratches, corrosion, contamination, and other damage during production, transportation, storage, and use. However, existing protective films generally suffer from the following core pain points, making it difficult to meet the needs of high-end applications and diverse environmental scenarios: 1. Limited functionality and poor environmental adaptability: Traditional protective films only have basic scratch and dust protection functions and cannot adapt to extreme temperature environments. They are prone to cracking in winter and softening and yellowing in summer. When used outdoors, their performance is easily degraded due to temperature changes. Especially in aerospace, outdoor construction and other fields, where temperature fluctuations are large, traditional protective films cannot achieve long-term stable protection. 2. Easily damaged and difficult to repair: Once the existing protective film is scratched, it cannot be repaired in place and must be replaced entirely. This not only increases the cost of use, but may also cause secondary damage to the substrate surface during the replacement process. This is especially true for precision components and high-end electronic equipment, where scratch repair is difficult and costly. 3. Significant problem of residual adhesive after peeling: The adhesive layer of traditional protective films mostly uses ordinary pressure-sensitive adhesive, which easily leaves adhesive residue when peeled off. This residue is difficult to clean, contaminates the substrate surface, and affects the product's appearance and subsequent use. Especially in the fields of precision electronics and optical components, residual adhesive can directly lead to product scrapping. 4. Poor functional synergy: Existing protective films with self-healing functions often suffer from low repair efficiency, require high temperature or special light source assistance, and cannot simultaneously achieve residue-free peeling and temperature adaptability; protective films with acid and alkali resistance and corrosion resistance lack self-healing ability and are difficult to achieve long-term stable protection. 5. Complex manufacturing process: Some functional protective films require complex processing equipment or rely on scarce raw materials, resulting in high production costs and difficulty in large-scale production, which limits their promotion and application.

[0003] Existing technologies, such as acid and alkali resistant UV-resistant protective films, only focus on acid and alkali resistance and residue-free peeling, lacking self-healing and temperature adaptability. While self-healing scratch-resistant protective films possess self-healing capabilities, they cannot achieve temperature self-adaptation, and the problem of residue peeling remains unresolved. Temperature-adaptive films are mostly used in building energy conservation, failing to address the core protective needs of protective films and thus cannot achieve synergy between scratch repair and residue-free peeling. Therefore, developing a protective film that combines temperature self-adaptation, in-situ self-healing, residue-free peeling, and is simple to prepare and cost-effective has become a pressing technical challenge for the industry. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a temperature-controlled adaptive in-situ self-healing residue-free protective film, its preparation method, and its application, aiming to partially solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: On the one hand, a temperature-controlled adaptive in-situ self-healing residue-free protective film is proposed, including a PET substrate layer, and a transparent hydrophobic layer with a moth-eye nanostructure, a thermochromic photothermal control layer, an in-situ self-healing layer, a low-adhesion residue-free interface layer and an adhesive layer, which are stacked on the surface of the PET substrate layer from top to bottom. The moth-eye-like nanostructure transparent hydrophobic layer is a film made of polydimethylsiloxane as the substrate and silane-modified nano-silica. The thermochromic photothermal control layer is a film made of poly(N-vinylcaprolactam) as substrate, with the addition of multi-walled carbon nanotubes and a eutectic mixture of n-heptadecane and n-octadecane; the mass ratio of n-heptadecane to n-octadecane is 20:80 to 80:20. The in-situ self-healing layer is a film made of polyurethane-disulfide copolymer as the substrate, with the addition of N,N'-(1,4-phenylene)bismaleimide, silane-modified boron nitride nanoparticles and multi-walled carbon nanotubes; The low-adhesion, residue-free interface layer is a film made of epoxy-modified acrylate pressure-sensitive adhesive as the base material, fluorinated acrylate, and modified clay that has undergone acid pretreatment and silane coupling agent modification.

[0006] As a preferred technical solution, the contact angle of the moth-eye nanostructure transparent hydrophobic layer is ≥150° and the light transmittance is ≥90%, which can achieve self-cleaning, UV protection and waterproof functions.

[0007] As a preferred technical solution, the photothermal regulation threshold of the thermochromic photothermal regulation layer is 24-28℃. When the temperature is below this threshold, it is transparent, allowing sunlight to pass through and absorb photothermal energy; when the temperature is above this threshold, it is opaque white, reflecting sunlight, thus achieving temperature adaptive regulation.

[0008] As a preferred technical solution, the transparent hydrophobic layer with moth-eye-like nanostructure has a thickness of 5-10 μm, the thermochromic photothermal control layer has a thickness of 10-20 μm, the in-situ self-healing layer has a thickness of 15-25 μm, the low-adhesion residue-free interface layer has a thickness of 5-10 μm, and the adhesive layer has a thickness of 3-5 μm.

[0009] Secondly, a method for preparing a temperature-controlled, adaptive, in-situ self-healing, residue-free protective film as described above is proposed, comprising the following steps: Raw material mixing: The raw materials for the moth-eye nanostructure transparent hydrophobic layer, the thermochromic photothermal control layer, the in-situ self-healing layer, and the low-adhesion residue-free interface layer are mixed evenly according to the formula ratio. Layered coating: On the surface of the PET substrate layer, the raw materials of the adhesive layer, the low-adhesion residue-free interface layer, the in-situ self-healing layer, the thermochromic photothermal control layer, and the moth-eye nanostructure transparent hydrophobic layer are sequentially coated in layers using a coating equipment. Curing and lamination: The coated film is sent into a drying equipment and dried at 40-120℃ for 8-12 minutes to achieve curing and lamination of each layer; Finished product processing: The surface of the transparent hydrophobic layer with the moth-eye nanostructure is treated by nanoimprinting process to form the moth-eye nanostructure. After slitting and winding, the finished protective film is obtained.

[0010] As a preferred technical solution, in the raw material mixing step, the stirring speed is 500-600 r / min and the stirring time is 25-50 min.

[0011] As a preferred technical solution, the formulation of the moth-eye-like nanostructure transparent hydrophobic layer includes 60-70 parts of polydimethylsiloxane as the base material and 3-5 parts of silane-modified nano-silica.

[0012] As a preferred technical solution, the formulation of the thermochromic photothermal control layer includes 50-60 parts of poly-N-vinylcaprolactam as the base material, 0.5-2 parts of multi-walled carbon nanotubes, and 5-10 parts of a eutectic mixture of n-heptadecane and n-octadecane.

[0013] As a preferred technical solution, the formulation of the in-situ self-healing layer includes 55-60 parts of polyurethane-disulfide copolymer as the base material, 8-15 parts of N,N'-(1,4-phenylene)bismaleimide, 6-10 parts of silane-modified nano boron nitride, and 0.4-0.8 parts of multi-walled carbon nanotubes.

[0014] As a preferred technical solution, the formulation of the low-adhesion, residue-free interface layer includes 30-50 parts of epoxy-modified acrylate pressure-sensitive adhesive base material, 1-10 parts of fluorinated acrylate, and 1-10 parts of modified clay that has been pretreated with acid and modified with silane coupling agent.

[0015] Thirdly, the application of the protective film prepared according to the above preparation method in the surface protection of precision components, electronic equipment, building components, aerospace parts or industrial equipment is also proposed.

[0016] Compared with the prior art, the technical solution of this application has the following beneficial effects: The protective film prepared by this invention: 1. It can achieve temperature adaptive adjustment and can work stably in the range of -20℃ to 60℃. In winter, it absorbs light and heat to prevent brittleness and icing, and in summer, it reflects sunlight to prevent softening and aging, adapting to the needs of multiple environments. 2. It has an in-situ self-healing function. When the scratch depth is ≤50μm, it can be completely repaired by irradiation with natural light or ordinary ultraviolet light (wavelength 365~405nm) for 1~5 minutes without the need for additional tools, thus reducing the cost of use; 3. No adhesive residue is left upon peeling, and the adhesion is controllable, ensuring that it will not fall off during use while allowing for easy peeling and avoiding secondary damage to the substrate; 4. Integrates multiple functions such as self-cleaning, acid and alkali resistance, scratch resistance, and UV aging resistance, improving the service life and protective effect of the protective film; 5. The preparation process is simplified, conventional processing equipment is used, raw materials are readily available, production costs are reduced, large-scale production is achieved, and the application range is expanded. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a temperature-controlled adaptive in-situ self-healing residue-free protective film provided by the present invention; Figure 2 This is a schematic diagram of the preparation method of a temperature-controlled adaptive in-situ self-healing residue-free protective film according to the present invention.

[0018] Figure labeling: 1. Moth-eye-like nanostructured transparent hydrophobic layer; 2. Thermochromic photothermal control layer; 3. In-situ self-healing layer; 4. Low-adhesion, residue-free interface layer; 5. Adhesive layer; 6. PET substrate layer. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figure 1 The present invention proposes a temperature-controlled adaptive in-situ self-healing residue-free protective film, comprising a PET substrate layer 6, and a transparent hydrophobic layer 1 with a moth-eye nanostructure, a thermochromic photothermal control layer 2, an in-situ self-healing layer 3, a low-adhesion residue-free interface layer 4, and an adhesive layer 5, which are stacked on the surface of the PET substrate layer 6 from top to bottom. The moth-eye-like nanostructure transparent hydrophobic layer 1 is a film layer made of polydimethylsiloxane as the substrate and silane-modified nano-silica. The thermochromic photothermal control layer 2 is a film layer made of poly(N-vinylcaprolactam) as substrate, with the addition of multi-walled carbon nanotubes and a eutectic mixture of n-heptadecane and n-octadecane; the mass ratio of n-heptadecane to n-octadecane is 20:80 to 80:20. The in-situ self-healing layer 3 is a film made of polyurethane-disulfide copolymer as the substrate, with added N,N'-(1,4-phenylene)bismaleimide, silane-modified nano-boron nitride, and multi-walled carbon nanotubes; The low-adhesion, residue-free interface layer 4 is a film layer made of epoxy-modified acrylate pressure-sensitive adhesive as the base material, fluorinated acrylate, and modified clay that has undergone acid pretreatment and silane coupling agent modification.

[0021] Preferably, the contact angle of the moth-eye nanostructured transparent hydrophobic layer 1 is ≥150° and the light transmittance is ≥90%, which enables it to achieve self-cleaning, UV protection and waterproof functions.

[0022] Preferably, the photothermal control threshold of the thermochromic photothermal control layer 2 is 24-28°C. When the temperature is below this threshold, it is transparent, allowing sunlight to pass through and absorb photothermal energy; when the temperature is above this threshold, it is opaque white, reflecting sunlight, thus achieving temperature adaptive adjustment.

[0023] Preferably, the thickness of the transparent hydrophobic layer 1 with the moth-eye nanostructure is 5-10 μm, the thickness of the thermochromic photothermal control layer 2 is 10-20 μm, the thickness of the in-situ self-healing layer 3 is 15-25 μm, the thickness of the low-adhesion residue-free interface layer 4 is 5-10 μm, and the thickness of the adhesive layer 5 is 3-5 μm.

[0024] Preferably, the adhesive layer 5 can be selected with a corresponding modified adhesive (such as silane coupling agent, titanate coupling agent, etc.) according to different substrates (such as metal, glass, plastic, etc.) to improve the adhesion between the protective film and the substrate and prevent it from falling off during use.

[0025] Specifically, the selection of modified adhesives: If the protective film is used on the surface of a metal substrate, γ-aminopropyltriethoxysilane (KH-550) can be used: a classic aminosilane coupling agent that can react with the hydroxyl groups on the metal surface to form chemical bonds. It is an excellent adhesion promoter and can significantly improve the adhesion to metals such as aluminum and iron.

[0026] If the protective film is used on the surface of a glass substrate, γ-aminopropyltriethoxysilane (KH-550) can be used: an aminosilane coupling agent. The silanol generated by hydrolysis reacts with the silanol on the glass surface to form covalent bonds, which can significantly improve the adhesion to the glass. It is suitable for polyurethane, epoxy and other adhesive systems.

[0027] Alternatively, γ-glycidoxypropyltrimethoxysilane (A-187, KH-560) can be used: an epoxy silane coupling agent that forms chemical bonds by condensing silanol with silanol on the glass surface. At the same time, the epoxy group can react with active groups such as amino and hydroxyl groups in the resin to enhance the bonding strength between the glass and the organic adhesive.

[0028] If the protective film is used on the surface of a plastic substrate, a coordination type titanate coupling agent (KH-401) can be selected: it can improve the adhesion to the plastic.

[0029] The protective film prepared by this invention has been tested and can achieve the following functions: (1) Temperature control adaptive function: It can work stably in the range of -20℃ to 60℃. When the temperature is below 24℃ to 28℃, it is in a transparent light and heat absorption state, and when the temperature is above this range, it is in a white light and heat reflection state, realizing the adaptive regulation of "warm in winter and cool in summer". (2) In-situ self-repair function: When the scratch depth is ≤50μm, it can be completely repaired by irradiation with natural light or ordinary ultraviolet light (wavelength 365~405nm) for 1~5min. After repair, the performance is consistent with the intact state. (3) No residue peeling function: No residue is left during peeling, the adhesion is controllable, and 100% interface peeling can be achieved, avoiding secondary damage to the substrate; (4) Multiple synergistic functions: It has functions such as self-cleaning (contact angle ≥150°), acid and alkali resistance, scratch resistance (surface hardness ≥3H), UV aging resistance, and anti-icing, with a service life of ≥3 years.

[0030] Based on the beneficial technical effects of the protective film of the present invention, the protective film of the present invention can be applied to the surface protection of precision components, electronic equipment, building components, aerospace parts and industrial equipment, and is especially suitable for scenarios with multiple temperature environments, easy to be scratched and damaged, and with strict requirements for no adhesive residue after peeling.

[0031] See Figure 2 The present invention provides a method for preparing a temperature-controlled adaptive in-situ self-healing residue-free protective film, comprising the following steps: Step 1: Raw material mixing: Mix the raw materials of the moth-eye nanostructure transparent hydrophobic layer 1, thermochromic photothermal control layer 2, in-situ self-healing layer 3 and low-adhesion residue-free interface layer 4 evenly according to the formula ratio. Step 2, Layered Coating: On the surface of the PET substrate layer 6, the raw materials of the adhesive layer 5, the low-adhesion residue-free interface layer 4, the in-situ self-healing layer 3, the thermochromic photothermal control layer 2, and the moth-eye nanostructure transparent hydrophobic layer 1 are sequentially coated in layers using a coating equipment. Step 3, Curing and Lamination: The coated film is sent to a drying equipment and dried at 40-120℃ for 8-12 minutes to achieve curing and lamination of each layer; Step 4, Finished product processing: The surface of the transparent hydrophobic layer 1 with the imitation moth eye nanostructure is treated by nanoimprinting process to form the imitation moth eye nanostructure. After slitting and winding, the finished protective film is obtained.

[0032] A moth-eye-like nano-protrusion structure, with a thickness of 5–10 μm, a contact angle ≥150°, and a light transmittance ≥90%, is formed through nanoimprinting technology, achieving self-cleaning, UV protection, and waterproofing functions. The nano-protrusion structure of the transparent superhydrophobic layer mimicking the moth eye allows water droplets to bounce off quickly, achieving a self-cleaning function. Simultaneously, its excellent light transmittance and UV shielding ability protect the underlying material from photoaging.

[0033] Preferably, in the raw material mixing step, the stirring speed is 500-600 r / min and the stirring time is 25-50 min.

[0034] Preferably, the formulation of the moth-eye-like nanostructure transparent hydrophobic layer 1 includes 60-70 parts of polydimethylsiloxane as the base material and 3-5 parts of silane-modified nano silica.

[0035] Preferably, the thermochromic photothermal control layer 2 comprises 50-60 parts of poly(N-vinylcaprolactam) base material, 0.5-2 parts of multi-walled carbon nanotubes, and 5-10 parts of a eutectic mixture of n-heptadecane and n-octadecane.

[0036] The thermochromic photothermal control layer 2 is the core of temperature self-adaptation, and its core components are thermochromic hydrogel and photothermal composite system. The lower critical dissolution temperature of the thermochromic hydrogel is precisely controlled between 24 and 28°C. When the ambient temperature is below this threshold (such as in winter), the hydrogel molecular chains are in an extended state and appear transparent. At this time, the multi-walled carbon nanotubes (photothermal conversion efficiency ≥91%) can efficiently absorb sunlight and convert solar energy into heat energy. On the one hand, this prevents the protective film from cracking due to low temperature, and on the other hand, it can achieve anti-icing function, extending the freezing time in the -20°C environment by more than 10 times. When the ambient temperature is above this threshold (such as in summer), the hydrogel molecular chains curl up and appear opaque white, which can reflect more than 60% of solar energy, avoiding excessive heating of the protective film surface (it can reduce the surface temperature by more than 17°C), preventing softening and yellowing, and reducing damage to the substrate caused by high temperature. This achieves adaptive regulation of "warm in winter and cool in summer" and solves the pain point of poor environmental adaptability of traditional protective films.

[0037] Preferably, the formulation of the in-situ self-healing layer 3 includes 55-60 parts of polyurethane-disulfide copolymer as the base material, 8-15 parts of N,N'-(1,4-phenylene)bismaleimide, 6-10 parts of silane-modified nano boron nitride, and 0.4-0.8 parts of multi-walled carbon nanotubes.

[0038] The core of the in-situ self-healing layer 3 is the reversible breakage and recombination of dynamic disulfide bonds. The polyurethane-disulfide copolymer molecular chain contains a large number of dynamic disulfide bonds. When scratches appear on the protective film surface, the molecular chain at the scratch site breaks, and the disulfide bonds break to form active sulfur free radicals. At this time, the carbon-based photothermal material absorbs the energy of natural light or ultraviolet light and transfers it to the breakage site, stimulating the active sulfur free radicals to recombine and form new disulfide bonds. Simultaneously, silane-modified nano-boron nitride acts as a crosslinking point, enhancing the bonding strength of the molecular chain and achieving rapid in-situ repair of scratches. Experimental verification shows that when the scratch depth is ≤50μm, irradiation for 1–5 minutes is sufficient for complete repair. After repair, the scratch resistance and light transmittance of the protective film are consistent with the intact state, eliminating the need for complete replacement and significantly reducing usage costs.

[0039] Preferably, the formulation of the low-adhesion, residue-free interface layer 4 includes 30-50 parts of an epoxy-modified acrylate pressure-sensitive adhesive base material, 1-10 parts of a fluorinated acrylate, and 1-10 parts of modified clay that has undergone acid pretreatment and silane coupling agent modification. Here, the unmodified clay is nano-clay, a functional material made from natural clay through chemical and physical processing. Optionally, the nano-clay can be montmorillonite or kaolin; in this case, modified clay is obtained through modification treatment.

[0040] The low-adhesion, residue-free interface layer 4 achieves controllable adjustment of adhesion through formulation optimization. Epoxy-modified acrylate pressure-sensitive adhesive provides basic viscoelasticity and cohesive strength, ensuring the protective film does not detach during use. The CF bond energy of the fluorinated acrylate is extremely high, exhibiting strong chemical inertness, and can form a hydrophobic interface on the adhesive layer surface, reducing the adhesion between the adhesive layer and the substrate. Modified clay, after acid pretreatment, has an increased specific surface area. Modification with a silane coupling agent significantly improves its compatibility with the organic phase, acting as a crosslinking point to greatly enhance the cohesive force of the adhesive layer and prevent residue breakage during peeling. Simultaneously, combined with UV light-assisted peeling (optional), the photoinitiator stimulates slight crosslinking and shrinkage of the adhesive layer, further reducing adhesion and achieving 100% interface peeling with no residue, solving the industry pain point of residue after traditional protective film peeling.

[0041] Example 1 This embodiment provides a temperature-controlled adaptive in-situ self-healing residue-free protective film, the formulation of each layer of which is as follows (by parts by weight): Transparent hydrophobic layer with moth-eye-like nanostructure: 65 parts polydimethylsiloxane and 4 parts silane-modified nano-silica.

[0042] Thermochromic photothermal control layer: 55 parts of poly(N-vinylcaprolactam), 1 part of multi-walled carbon nanotubes, and 8 parts of a eutectic mixture of n-heptadecane and n-octadecane (mass ratio 50:50).

[0043] In-situ self-healing layer: 58 parts polyurethane-disulfide copolymer, 12 parts N,N'-(1,4-phenylene)bismaleimide, 8 parts silane-modified nano boron nitride, and 0.6 parts multi-walled carbon nanotubes.

[0044] Low-adhesion, residue-free interface layer: 40 parts epoxy-modified acrylate pressure-sensitive adhesive, 5 parts fluorinated acrylate, and 5 parts modified clay (pretreated with acid and modified with silane coupling agent).

[0045] Adhesive layer: γ-aminopropyltriethoxysilane (KH-550) modified adhesive is selected, which is suitable for metal substrates.

[0046] The thickness of each layer is as follows: moth-eye-like layer 8μm, thermochromic layer 15μm, self-healing layer 20μm, low-adhesion layer 8μm, and adhesive layer 4μm.

[0047] 2. Preparation method Raw material mixing: Weigh the raw materials for each layer according to the formula ratio, stir at 550 r / min for 35 min, and mix evenly.

[0048] Layered coating: On the surface of the PET substrate layer, an adhesive layer, a low-adhesion residue-free interface layer, an in-situ self-healing layer, a thermochromic photothermal control layer, and a transparent hydrophobic layer with a moth-eye-like nanostructure are coated sequentially.

[0049] Curing and lamination: Dry at 80℃ for 10 min.

[0050] Finished product processing: A moth-eye-like nanostructure is formed on the surface through nanoimprinting technology, and then the finished protective film is obtained through slitting and winding.

[0051] 3. Performance Test Results Temperature control adaptive: The film does not crack at -20℃, and the surface temperature is 12℃ higher than the control group without film; at 60℃, the surface temperature is 15℃ lower than the control group, and the light transmittance changes from transparent (89%) to white opaque (62% reflectance), with an adjustment threshold of about 26℃.

[0052] In-situ self-healing: A scratch with a depth of 45μm is created using a scratcher. After being irradiated under natural light (wavelength 365~405nm) for 3 minutes, the scratch completely disappears. After repair, the surface hardness is restored to 3H, and the light transmittance is restored from 82% before repair to 91%.

[0053] No adhesive residue after peeling: There is no adhesive residue on the surface of the metal substrate after peeling, and the peel strength is 0.8N / 25mm, achieving 100% interface peeling.

[0054] Self-cleaning and weather resistance: The contact angle is 152° and the light transmittance is 91%. After being immersed in acidic solution with pH=2 and alkaline solution with pH=12 for 48 hours, the film did not peel off or change color and maintained its intact structure.

[0055] Example 2 This embodiment involves studying the varying proportions of phase change material in the thermochromic layer: Transparent hydrophobic layer with moth-eye-like nanostructure: 70 parts polydimethylsiloxane and 3 parts silane-modified nano-silica.

[0056] Thermochromic photothermal control layer: 60 parts poly-N-vinylcaprolactam, 0.8 parts multi-walled carbon nanotubes, and 10 parts a eutectic mixture of n-heptadecane and n-octadecane (mass ratio 30:70).

[0057] In-situ self-healing layer: The formula is the same as in Example 1.

[0058] Low-adhesion, residue-free interface layer: 35 parts epoxy-modified acrylate pressure-sensitive adhesive, 8 parts fluorinated acrylate, and 8 parts modified clay.

[0059] Adhesive layer: γ-glycidyl oxypropyltrimethoxysilane (KH-560) is selected, which is suitable for glass substrates.

[0060] Thickness of each layer: moth-eye-like layer 6μm, thermochromic layer 18μm, self-healing layer 22μm, low-adhesion layer 6μm, adhesive layer 3μm.

[0061] 2. Preparation method Raw material mixing: Stirring speed 600 r / min, stirring time 30 min.

[0062] Layered coating: Same as in Example 1.

[0063] Curing and lamination: Dry at 100℃ for 8 minutes.

[0064] Finished product processing: Same as in Example 1.

[0065] 3. Performance Test Results Temperature control adaptive: The control threshold is 25℃. At low temperatures (-20℃), the film is transparent and absorbs light and heat, increasing the surface temperature by 10℃, effectively preventing icing; at high temperatures (60℃), the film quickly turns white and opaque, with a reflectivity of 65%, and the surface temperature decreases by 18℃.

[0066] In-situ self-healing: A scratch with a depth of 30μm was completely repaired after 2 minutes of irradiation with ultraviolet light (wavelength 365nm). The light transmittance after repair was 92%, and the surface hardness was 3H.

[0067] No residue after peeling: There is no residue on the glass surface after peeling, and the peel strength is 0.7N / 25mm.

[0068] Self-cleaning and weather resistance: Contact angle is 153°, light transmittance is 90.5%; acid and alkali resistance tests are passed, and accelerated aging tests show no performance degradation for ≥3 years.

[0069] Example 3 This embodiment focuses on the repair efficiency and mechanical strength of the in-situ self-healing layer: Transparent hydrophobic layer with moth-eye-like nanostructure: 60 parts polydimethylsiloxane and 5 parts silane-modified nano-silica.

[0070] Thermochromic photothermal control layer: The formulation is the same as in Example 1.

[0071] In-situ self-healing layer: 60 parts polyurethane-disulfide copolymer, 15 parts N,N'-(1,4-phenylene)bismaleimide, 10 parts silane-modified nano boron nitride, and 0.8 parts multi-walled carbon nanotubes.

[0072] Low-adhesion, residue-free interface layer: 45 parts epoxy-modified acrylate pressure-sensitive adhesive, 6 parts fluorinated acrylate, and 6 parts modified clay.

[0073] Adhesive layer: Titanate coupling agent (KH-401) is selected, suitable for plastic substrates.

[0074] Thickness of each layer: moth-eye-like layer 10μm, thermochromic layer 12μm, self-healing layer 25μm, low-adhesion layer 10μm, adhesive layer 5μm.

[0075] 2. Preparation method Raw material mixing: stirring speed 500 r / min, stirring time 45 min.

[0076] Layered coating: Same as in Example 1.

[0077] Curing and lamination: Dry at 60℃ for 12 minutes.

[0078] Finished product processing: Same as in Example 1.

[0079] 3. Performance Test Results Temperature control adaptive: The control threshold is 27℃. It exhibits stable low-temperature heat absorption and high-temperature reflectivity, with surface temperature control ranges of +11℃ and -16℃, respectively.

[0080] In-situ self-healing: A scratch with a depth of 50 μm was completely repaired after being exposed to natural light for 4 minutes. The surface hardness after repair was 3H, and the light transmittance was restored from 80% to 90%. The repair efficiency was improved by about 20% compared with Example 1.

[0081] No residue after peeling: There is no residue on the surface of the plastic substrate after peeling, and the peel strength is 0.9N / 25mm.

[0082] Self-cleaning and weather resistance: The contact angle is 151° and the light transmittance is 90%; it has excellent acid and alkali resistance and UV aging resistance, and the contact angle remains above 148° after aging test.

[0083] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A temperature-controlled self-adaptive in-situ self-repairing residue-free protective film, characterized in that, It includes a PET substrate layer, and a transparent hydrophobic layer with a moth-eye-like nanostructure, a thermochromic photothermal control layer, an in-situ self-healing layer, a low-adhesion residue-free interface layer, and an adhesive layer, which are stacked on the surface of the PET substrate layer from top to bottom. The moth-eye-like nanostructured transparent hydrophobic layer is a film made of polydimethylsiloxane as the substrate and silane-modified nano-silica. The thermochromic photothermal control layer is a film made of poly(N-vinylcaprolactam) as substrate, with the addition of multi-walled carbon nanotubes and a eutectic mixture of n-heptadecane and n-octadecane; the mass ratio of n-heptadecane to n-octadecane is 20:80 to 80:

20. The in-situ self-healing layer is a film made of polyurethane-disulfide copolymer as the substrate, with the addition of N,N'-(1,4-phenylene)bismaleimide, silane-modified boron nitride nanoparticles and multi-walled carbon nanotubes; The low-adhesion, residue-free interface layer is a film made of epoxy-modified acrylate pressure-sensitive adhesive as the base material, fluorinated acrylate, and modified clay that has undergone acid pretreatment and silane coupling agent modification.

2. The temperature-dependent self-healing in-situ repair no-residue protective film according to claim 1, characterized in that, The transparent hydrophobic layer with the moth-eye-like nanostructure has a contact angle ≥150° and a light transmittance ≥90%, enabling it to achieve self-cleaning, UV protection, and waterproofing functions. 3.The temperature-controllable self-adapting in-situ self-repairing residue-free protective film according to claim 1, wherein, The transparent hydrophobic layer with the moth-eye-like nanostructure has a thickness of 5–10 μm, the thermochromic photothermal control layer has a thickness of 10–20 μm, the in-situ self-healing layer has a thickness of 15–25 μm, the low-adhesion, residue-free interface layer has a thickness of 5–10 μm, and the adhesive layer has a thickness of 3–5 μm.

4. A method for preparing a temperature-controlled self-adapting in-situ self-repairing residue-free protective film according to any one of claims 1-3, characterized in that, Includes the following steps: Raw material mixing: The raw materials for the moth-eye nanostructure transparent hydrophobic layer, the thermochromic photothermal control layer, the in-situ self-healing layer, and the low-adhesion residue-free interface layer are mixed evenly according to the formula ratio. Layered coating: On the surface of the PET substrate layer, the raw materials of the adhesive layer, the low-adhesion residue-free interface layer, the in-situ self-healing layer, the thermochromic photothermal control layer, and the moth-eye nanostructure transparent hydrophobic layer are sequentially coated in layers using a coating equipment. Curing and lamination: The coated film is sent into a drying equipment and dried at 40-120℃ for 8-12 minutes to achieve curing and lamination of each layer; Finished product processing: The surface of the transparent hydrophobic layer of the moth-eye nanostructure is treated by nanoimprinting process to form a moth-eye nanostructure. After slitting and winding, the finished protective film is obtained.

5. The preparation method according to claim 4, characterized in that, In the raw material mixing step, the stirring speed is 500-600 r / min and the stirring time is 25-50 min.

6. The preparation method according to claim 4, characterized in that, The formulation of the moth-eye-like nanostructured transparent hydrophobic layer includes 60-70 parts of polydimethylsiloxane as the base material and 3-5 parts of silane-modified nano-silica.

7. The preparation method according to claim 4, characterized in that, The formulation of the thermochromic photothermal control layer includes 50-60 parts of poly(N-vinylcaprolactam) base material, 0.5-2 parts of multi-walled carbon nanotubes, and 5-10 parts of a eutectic mixture of n-heptadecane and n-octadecane.

8. The preparation method according to claim 4, characterized in that, The formulation of the in-situ self-healing layer includes 55-60 parts of polyurethane-disulfide copolymer as the base material, 8-15 parts of N,N'-(1,4-phenylene)bismaleimide, 6-10 parts of silane-modified nano boron nitride, and 0.4-0.8 parts of multi-walled carbon nanotubes.

9. The preparation method according to claim 4, characterized in that, The formulation of the low-adhesion, residue-free interface layer includes 30-50 parts of epoxy-modified acrylate pressure-sensitive adhesive base material, 1-10 parts of fluorinated acrylate, and 1-10 parts of modified clay that has been pretreated with acid and modified with silane coupling agent.

10. The application of a protective film prepared by the preparation method according to any one of claims 4-9 in the surface protection of precision components, electronic devices, building components, aerospace parts or industrial equipment.

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