Nano tungsten oxide solar film and preparation method thereof

Abstract

The invention relates to the technical field of film production, and discloses a nano tungsten oxide solar film and a preparation method thereof.The solar film is composed of a film material, an adhesive and a protective film, one side of the film material is coated with the adhesive, and the surface of the adhesive is covered with the protective film. According to the technology, the heat insulation efficiency, the waterproof and antifouling performance and the mechanical stability are improved, excellent weather resistance and bonding reliability are achieved, the tape casting technology is adopted in the whole preparation technology, the process is continuous and controllable, large-scale production is facilitated, and the prepared solar film meets the use requirements of vehicle windows, building glass and other scenes.

Description

Technical Field

[0001] This invention relates to the field of thin film production technology, specifically to a nano-tungsten oxide solar film and its preparation method. Background Technology

[0002] Solar film, a functional material with heat insulation and sun protection properties, is widely used in architectural glass, automotive windows, and other fields. Its core function is to block near-infrared and ultraviolet rays from solar radiation while ensuring high visible light transmittance, thereby achieving energy-saving and comfortable use. Traditional solar films often use metal coatings or dye colorants as functional components. However, metal coatings have problems such as low visible light transmittance, easy oxidation and corrosion, and interference with communication signals, while dye colorants have drawbacks such as poor weather resistance, limited heat insulation effect, and easy fading. Nano-tungsten oxide, as a novel semiconductor material, possesses unique near-infrared light blocking properties. Its band gap is tunable, it is transparent in the visible light region, and exhibits strong absorption and scattering of near-infrared light. Furthermore, it boasts high chemical stability and strong weather resistance, making it an ideal functional material for preparing high-performance solar films. However, nano-tungsten oxide particles are prone to agglomeration, leading to uneven dispersion of the functional layer and affecting heat insulation and light transmittance. Therefore, developing a uniformly dispersed and stable nano-tungsten oxide solar film is of significant practical importance. Summary of the Invention

[0003] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a nano-tungsten oxide solar film and its preparation method.

[0004] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, a nano-tungsten oxide solar film is provided, the solar film comprising a film material, an adhesive, and a protective film, wherein the adhesive is applied to one side of the film material and the protective film covers the surface of the adhesive. Membrane material: made from the following raw materials in parts by weight: 60-80 parts modified polyethylene terephthalate, 5-10 parts nano tungsten oxide, 2-5 parts mica functional filler, 3-8 parts film-forming aid, 0.5-1.5 parts defoamer, 0.1-0.5 parts ultraviolet absorber, 0.2-0.8 parts antioxidant, and 30-60 parts solvent; Adhesive: Solvent-free acrylic pressure-sensitive adhesive; Protective film: Polyethylene release film.

[0005] Furthermore, the preparation method of modified polyethylene terephthalate includes the following steps: A1. Add 3-8 parts of graphite to 50-80 parts of 70-75% ethanol aqueous solution, adjust the pH to 3-4 with glacial acetic acid, add 0.3-0.8 parts of γ-aminopropyltriethoxysilane, heat to 60-70℃, keep warm and stir for 1-2 h, filter, wash 1-3 times with anhydrous ethanol, and dry at 80-100℃ for 4-6 h to obtain activated graphite; A2. Using a twin-screw extruder, add 100-120 parts of polyethylene terephthalate and 5-8 parts of glycidyl methacrylate through the main feed port, add activated graphite through the side feed port, and add 3-6 parts of modifier and 0.05-0.1 parts of tetrabutyl titanate through the liquid feed port. Melt-blend in the extruder, extrude through a die, cool with water, pelletize, and dry at 100-120℃ for 2-4 hours to obtain modified polyethylene terephthalate.

[0006] Furthermore, in step A2, the parameters of the twin-screw extruder are set as follows: screw temperature: zone 1 220~240℃, zone 2 250~255℃, zone 3 260~280℃, die head 245~255℃, screw speed 200~250 r / min.

[0007] Furthermore, the preparation method of the modifier in step A2 includes the following steps: B1. Add 10-20 parts of methyltrichlorosilane and 120-200 parts of anhydrous tetrahydrofuran to the flask, stir and cool to -10 to 0°C, slowly add 60-90 parts of a 10-15% tetrahydrofuran solution of 3,3,3-trifluoropropylmagnesium chloride, after the addition is complete, raise the temperature to 25-30°C, keep warm and stir for 4-6 hours; B2. Add 3-5 parts of anhydrous zinc chloride to the above reaction solution, stir and activate for 10-15 min, then slowly add 10-15 parts of 3-chloropropanol, heat to reflux temperature, and keep the reaction at this temperature for 8-10 h. B3. Slowly pour the reaction solution into 100-150 parts of a 10-20% ammonium chloride aqueous solution, stir for 10-30 minutes, allow to stand and separate into layers, collect the upper organic phase, wash the organic phase with deionized water until neutral, add 5-10 parts of anhydrous magnesium sulfate to the organic phase, stir and dry at room temperature for 10-12 hours, filter to remove the desiccant, transfer the filtrate to a vacuum distillation apparatus, control the vacuum degree to 10-20 Pa and the distillation temperature to 120-130℃, collect the fraction to obtain the modifier.

[0008] Furthermore, the nano-tungsten oxide particles have a diameter of 10~50 nm, and the mica functional filler particles have a diameter of 1500~2000 mesh.

[0009] Furthermore, the film-forming aid is one of alcohol ester-12 and ethylene glycol butyl ether; the defoamer is one of defoamer BYK-052, defoamer DF-100, and defoamer GP-330; the ultraviolet absorber is one of UV-327, UV-P, and UV-531; the antioxidant is one of antioxidant 1010, antioxidant 168, and antioxidant DLTP; and the solvent is one of propylene glycol methyl ether acetate, ethyl acetate, and N,N-dimethylformamide.

[0010] Furthermore, the solvent-free acrylate pressure-sensitive adhesive has a viscosity of 200~400 cP, and the polyethylene release film is made of low-density polyethylene with a thickness of 25~50 μm.

[0011] A second aspect of the present invention provides a method for preparing a nano-tungsten oxide solar film, comprising the following steps: S1. Add solvent to the reactor, start stirring at 600~800 r / min, slowly add modified polyethylene terephthalate, heat to 60~80℃, keep stirring for 1~2 h, cool to 50~55℃, add nano tungsten oxide and mica functional filler, stir at 1200~1500 r / min for 10~20 min, cool to room temperature, add film-forming aid, ultraviolet absorber and antioxidant in sequence, stir at 600~800 r / min for 10~20 min, then grind in a sand mill, add defoamer, stir at 300~500 r / min for 10~15 min, vacuum degas at -0.09~-0.095 MPa for 10~20 min to obtain composite slurry; S2. Select a single-screw casting machine with a die width of 1.2~1.5 m and a die gap of 80~120 μm. The composite slurry is evenly conveyed to the casting machine die at a conveying pressure of 0.3~0.5 MPa. The slurry is evenly spread on the preheated conveyor belt through the die to form a continuous and uniform wet film. After forming, it is sent to an oven at a temperature of 100~120℃ for 10~15 min. After curing, the film is cooled by a cooling roller at 25~30℃ and then wound up by a winding machine with a winding tension controlled at 5~8 N to obtain the film material. S3. Using a micro-grooving coating method, solvent-free acrylic pressure-sensitive adhesive is uniformly coated on one side of the film material, controlling the adhesive layer thickness to be 10~15 μm. Immediately after coating, a polyethylene release film is placed on the adhesive surface, and the film is pressed by a composite roller at a pressure of 0.3~0.5 MPa and a temperature of 40~50℃. After pressing, the film is placed in a constant temperature and humidity environment at a temperature of 22~25℃ and a humidity of 40~50% for 12~24 h to finally obtain a nano-tungsten oxide solar film.

[0012] (iii) Beneficial technical effects In the preparation process of the modified polyethylene terephthalate of this invention, activated graphite, fluorosilicone modifier, and glycidyl methacrylate achieve chemical bonding through melt blending. This not only optimizes the mechanical properties and surface characteristics of the matrix material but also enhances its compatibility with nano-tungsten oxide and mica functional fillers, effectively preventing the agglomeration of functional components and ensuring the uniformity and density of the membrane structure. Nano-tungsten oxide can efficiently shield near-infrared light, while mica functional fillers can improve light reflection and anti-glare effects. The addition of various additives such as film-forming aids and dispersants not only improves the casting and molding effect of the composite slurry but also ensures the smoothness and density of the membrane surface and extends its service life. The appropriate selection of solvent-free acrylic pressure-sensitive adhesive and polyethylene release film ensures a strong bond between the membrane and the substrate while also taking into account easy peeling during construction, avoiding residue problems.

[0013] The process of this invention improves heat insulation efficiency, waterproof and stain-resistant performance and mechanical stability, and has excellent weather resistance and adhesion reliability. The entire preparation process adopts casting molding technology, the process is continuous and controllable, which is conducive to large-scale production. The prepared solar film is suitable for the use needs of car windows, architectural glass and other scenarios. Detailed Implementation

[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0015] Unless otherwise specified, all components of the nano-tungsten oxide solar film formulation of this invention are commercially available. Polyethylene terephthalate was purchased from Sinopec Yizheng Chemical Fiber Co., Ltd. The mica functional filler was muscovite, purchased from Lingshou County Huizi Mineral Products Co., Ltd. The polyethylene release film was purchased from Hangzhou Xingyuan Release Film Co., Ltd., with a density of 0.910~0.925 g / cm³. 3 ; All parts used in this invention are parts by weight; Example 1 A nano-tungsten oxide solar film, the solar film being composed of a film material, an adhesive, and a protective film, wherein the adhesive is applied to one side of the film material and the protective film covers the surface of the adhesive; Membrane material: made from the following raw materials in parts by weight: 60 parts modified polyethylene terephthalate, 5 parts nano tungsten oxide, 2 parts mica functional filler, 3 parts film-forming aid, 0.5 parts defoamer, 0.1 parts ultraviolet absorber, 0.2 parts antioxidant, and 30 parts solvent; Adhesive: Solvent-free acrylic pressure-sensitive adhesive; Protective film: Polyethylene release film.

[0016] The nano-tungsten oxide particles have a diameter of 10 nm, and the mica functional filler particles have a diameter of 1500 mesh.

[0017] The film-forming aid is alcohol ester-12; The defoamer is defoamer BYK-052; The ultraviolet absorber is UV-327; The antioxidant is antioxidant 1010; The solvent is propylene glycol methyl ether acetate.

[0018] The solvent-free acrylate pressure-sensitive adhesive has a viscosity of 200 cP, and the polyethylene release film is made of low-density polyethylene with a thickness of 25 μm.

[0019] The preparation method of modified polyethylene terephthalate includes the following steps: A1. Add 3 parts of graphite to 50 parts of 70% ethanol aqueous solution, adjust the pH to 3 with glacial acetic acid, add 0.3 parts of γ-aminopropyltriethoxysilane, heat to 60℃, keep warm and stir for 1 h, filter, wash once with anhydrous ethanol, and dry at 80℃ for 4 h to obtain activated graphite. A2. Using a twin-screw extruder, 100 parts of polyethylene terephthalate and 5 parts of glycidyl methacrylate are added through the main feed port, activated graphite is added through the side feed port, and 3 parts of modifier and 0.05 parts of tetrabutyl titanate are added through the liquid feed port. The mixture is melt-blended in the extruder, extruded through a die, water-cooled, pelletized, and dried at 100°C for 2 hours to obtain modified polyethylene terephthalate.

[0020] In step A2, the parameters of the twin-screw extruder are set as follows: screw temperature: zone 1 220℃, zone 2 250℃, zone 3 260℃, die head 245℃, screw speed 200 r / min.

[0021] The preparation method of the modifier in step A2 includes the following steps: B1. Add 10 parts of methyltrichlorosilane and 120 parts of anhydrous tetrahydrofuran to the flask, stir and cool to -10°C, slowly add 60 parts of 10% tetrahydrofuran solution of 3,3,3-trifluoropropylmagnesium chloride, and after the addition is complete, raise the temperature to 25°C and keep it warm and stirring for 4 hours. B2. Add 3 parts of anhydrous zinc chloride to the above reaction solution, stir and activate for 10 min, then slowly add 10 parts of 3-chloropropanol, heat to reflux temperature, and keep the reaction at this temperature for 8 h. B3. Slowly pour the reaction solution into 100 parts by mass of 10% ammonium chloride aqueous solution, stir for 10 min, let stand for separation, collect the upper organic phase, wash the organic phase with deionized water until neutral, add 5 parts of anhydrous magnesium sulfate to the organic phase, stir and dry at room temperature for 10 h, filter to remove the desiccant, transfer the filtrate to a vacuum distillation apparatus, control the vacuum degree to 10 Pa and the distillation temperature to 120℃, collect the fraction to obtain the modifier.

[0022] A method for preparing a nano-tungsten oxide solar film includes the following steps: S1. Add solvent to the reactor, start stirring at 600 r / min, slowly add modified polyethylene terephthalate, heat to 60℃, keep stirring for 1 h, cool to 50℃, add nano tungsten oxide and mica functional filler, stir at 1200 r / min for 10 min, cool to room temperature, add film-forming aid, ultraviolet absorber and antioxidant in sequence, stir at 600 r / min for 10 min, then grind in a sand mill, add defoamer, stir at 300 r / min for 10 min, degas under -0.09 MPa vacuum for 10 min to obtain composite slurry; S2. A single-screw casting machine is selected with a die head width of 1.2 m and a die head gap of 80 μm. The composite slurry is uniformly conveyed to the casting machine die head at a conveying pressure of 0.3 MPa. The slurry is evenly spread on the preheated conveyor belt through the die head to form a continuous and uniform wet film. After forming, it is sent to an oven at a temperature of 100℃ for 10 min. After curing, the film material is cooled by a 25℃ cooling roller and then wound up by a winding machine with the winding tension controlled at 5 N to obtain the film material. S3. Using a micro-grooving method, solvent-free acrylic pressure-sensitive adhesive is uniformly coated on one side of the film material, controlling the adhesive layer thickness to 10 μm. Immediately after coating, a polyethylene release film is placed on the adhesive surface, and the film is pressed by a composite roller at a pressure of 0.3 MPa and a temperature of 40°C. After pressing, the film is placed in a constant temperature and humidity environment at a temperature of 22°C and a humidity of 40% for 12 hours to finally obtain a nano-tungsten oxide solar film.

[0023] Example 2 A nano-tungsten oxide solar film, the solar film being composed of a film material, an adhesive, and a protective film, wherein the adhesive is applied to one side of the film material and the protective film covers the surface of the adhesive; Membrane material: made from the following raw materials in parts by weight: 70 parts modified polyethylene terephthalate, 8 parts nano tungsten oxide, 3 parts mica functional filler, 5 parts film-forming aid, 1 part defoamer, 0.3 parts ultraviolet absorber, 0.5 parts antioxidant and 40 parts solvent; Adhesive: Solvent-free acrylic pressure-sensitive adhesive; Protective film: Polyethylene release film.

[0024] The nano-tungsten oxide particles have a diameter of 30 nm, and the mica functional filler particles have a diameter of 1500 mesh.

[0025] The film-forming aid is ethylene glycol butyl ether; The defoamer is defoamer DF-100; The ultraviolet absorber is UV-P; The antioxidant is antioxidant 168; The solvent is ethyl acetate.

[0026] The solvent-free acrylate pressure-sensitive adhesive has a viscosity of 300 cP, and the polyethylene release film is made of low-density polyethylene with a thickness of 30 μm.

[0027] The preparation method of modified polyethylene terephthalate includes the following steps: A1. Add 5 parts of graphite to 60 parts of 70% ethanol aqueous solution, adjust the pH to 3 with glacial acetic acid, add 0.5 parts of γ-aminopropyltriethoxysilane, heat to 65℃, keep warm and stir for 1.5 h, filter, wash twice with anhydrous ethanol, and dry at 90℃ for 5 h to obtain activated graphite. A2. Using a twin-screw extruder, 110 parts of polyethylene terephthalate and 6 parts of glycidyl methacrylate were added from the main feed port, activated graphite was added from the side feed port, and 5 parts of modifier and 0.08 parts of tetrabutyl titanate were added from the liquid feed port. The mixture was melt-blended in the extruder, extruded through a die, water-cooled, pelletized, and dried at 110°C for 3 hours to obtain modified polyethylene terephthalate.

[0028] In step A2, the parameters of the twin-screw extruder are set as follows: screw temperature: zone 1 230℃, zone 2 255℃, zone 3 270℃, die head 250℃, screw speed 220 r / min.

[0029] The preparation method of the modifier in step A2 includes the following steps: B1. Add 15 parts of methyltrichlorosilane and 150 parts of anhydrous tetrahydrofuran to the flask, stir and cool to -5°C, slowly add 70 parts of 12% tetrahydrofuran solution of 3,3,3-trifluoropropylmagnesium chloride, and after the addition is complete, raise the temperature to 28°C and keep it warm and stirring for 5 h. B2. Add 4 parts of anhydrous zinc chloride to the above reaction solution, stir and activate for 10 min, then slowly add 12 parts of 3-chloropropanol, heat to reflux temperature, and keep the reaction at this temperature for 9 h. B3. Slowly pour the reaction solution into 120 parts of 15% ammonium chloride aqueous solution, stir for 20 min, let stand for separation, collect the upper organic phase, wash the organic phase with deionized water until neutral, add 6 parts of anhydrous magnesium sulfate to the organic phase, stir and dry at room temperature for 10 h, filter to remove the desiccant, transfer the filtrate to a vacuum distillation apparatus, control the vacuum degree to 15 Pa and the distillation temperature to 125℃, collect the fraction to obtain the modifier.

[0030] A method for preparing a nano-tungsten oxide solar film includes the following steps: S1. Add solvent to the reactor, start stirring at 700 r / min, slowly add modified polyethylene terephthalate, heat to 70℃, keep stirring for 1.5 h, cool to 52℃, add nano tungsten oxide and mica functional filler, stir at 1300 r / min for 15 min, cool to room temperature, add film-forming aid, ultraviolet absorber and antioxidant in sequence, stir at 700 r / min for 15 min, then grind in a sand mill, add defoamer, stir at 400 r / min for 10 min, degas under vacuum at -0.095MPa for 15 min to obtain composite slurry; S2. A single-screw casting machine is selected with a die head width of 1.5 m and a die head gap of 100 μm. The composite slurry is uniformly conveyed to the casting machine die head at a conveying pressure of 0.4 MPa. The slurry is evenly spread on the preheated conveyor belt through the die head to form a continuous and uniform wet film. After forming, it is sent into an oven at a temperature of 110℃ for 10 min. After curing, the film material is cooled by a 25℃ cooling roller and then wound up by a winding machine with the winding tension controlled at 6 N to obtain the film material. S3. Using a micro-grooving method, solvent-free acrylic pressure-sensitive adhesive is uniformly coated on one side of the film material, controlling the adhesive layer thickness to 10 μm. Immediately after coating, a polyethylene release film is placed on the adhesive surface, and the film is pressed by a composite roller at a pressure of 0.4 MPa and a temperature of 45°C. After pressing, the film is placed in a constant temperature and humidity environment at a temperature of 25°C and a humidity of 45% for 16 hours to finally obtain a nano-tungsten oxide solar film.

[0031] Example 3 A nano-tungsten oxide solar film, the solar film being composed of a film material, an adhesive, and a protective film, wherein the adhesive is applied to one side of the film material and the protective film covers the surface of the adhesive; Membrane material: made from the following raw materials in parts by weight: 80 parts modified polyethylene terephthalate, 10 parts nano tungsten oxide, 5 parts mica functional filler, 8 parts film-forming aid, 1.5 parts defoamer, 0.5 parts ultraviolet absorber, 0.8 parts antioxidant, and 60 parts solvent; Adhesive: Solvent-free acrylic pressure-sensitive adhesive; Protective film: Polyethylene release film.

[0032] The nano-tungsten oxide particles have a diameter of 50 nm, and the mica functional filler particles have a diameter of 2000 mesh.

[0033] The film-forming aid is alcohol ester-12; The defoamer is defoamer GP-330; The ultraviolet absorber is UV-531; The antioxidant is DLTP. The solvent is N,N-dimethylformamide.

[0034] The solvent-free acrylate pressure-sensitive adhesive has a viscosity of 400 cP, and the polyethylene release film is made of low-density polyethylene with a thickness of 50 μm.

[0035] The preparation method of modified polyethylene terephthalate includes the following steps: A1. Add 8 parts of graphite to 80 parts of 75% ethanol aqueous solution, adjust the pH to 4 with glacial acetic acid, add 0.8 parts of γ-aminopropyltriethoxysilane, heat to 70℃, keep warm and stir for 2 h, filter, wash 3 times with anhydrous ethanol, and dry at 100℃ for 6 h to obtain activated graphite. A2. Using a twin-screw extruder, 120 parts of polyethylene terephthalate and 8 parts of glycidyl methacrylate were added from the main feed port, activated graphite was added from the side feed port, and 6 parts of modifier and 0.1 parts of tetrabutyl titanate were added from the liquid feed port. The mixture was melt-blended in the extruder, extruded through a die, water-cooled, pelletized, and dried at 120°C for 4 hours to obtain modified polyethylene terephthalate.

[0036] In step A2, the parameters of the twin-screw extruder are set as follows: screw temperature: zone 1 240℃, zone 2 255℃, zone 3 280℃, die head 255℃, screw speed 250 r / min.

[0037] The preparation method of the modifier in step A2 includes the following steps: B1. Add 20 parts of methyltrichlorosilane and 200 parts of anhydrous tetrahydrofuran to the flask, stir and cool to 0°C, slowly add 90 parts of 15% tetrahydrofuran solution of 3,3,3-trifluoropropylmagnesium chloride, and after the addition is complete, raise the temperature to 30°C and keep it warm and stirring for 6 hours. B2. Add 5 parts of anhydrous zinc chloride to the above reaction solution, stir and activate for 15 min, then slowly add 15 parts of 3-chloropropanol, heat to reflux temperature, and keep the reaction at this temperature for 10 h. B3. Slowly pour the reaction solution into 150 parts of 20% ammonium chloride aqueous solution, stir for 30 min, let stand for separation, collect the upper organic phase, wash the organic phase with deionized water until neutral, add 10 parts of anhydrous magnesium sulfate to the organic phase, stir and dry at room temperature for 12 h, filter to remove the desiccant, transfer the filtrate to a vacuum distillation apparatus, control the vacuum degree to 20 Pa and the distillation temperature to 130℃, collect the fraction to obtain the modifier.

[0038] A method for preparing a nano-tungsten oxide solar film includes the following steps: S1. Add solvent to the reactor, start stirring at 800 r / min, slowly add modified polyethylene terephthalate, heat to 80℃, keep stirring for 2 h, cool to 55℃, add nano tungsten oxide and mica functional filler, stir at 1500 r / min for 20 min, cool to room temperature, add film-forming aid, ultraviolet absorber and antioxidant in sequence, stir at 800 r / min for 20 min, then grind in a sand mill, add defoamer, stir at 500 r / min for 15 min, degas under vacuum at -0.095 MPa for 20 min to obtain composite slurry; S2. A single-screw casting machine is selected with a die head width of 1.5 m and a die head gap of 120 μm. The composite slurry is evenly conveyed to the casting machine die head at a conveying pressure of 0.5 MPa. The slurry is evenly spread on the preheated conveyor belt through the die head to form a continuous and uniform wet film. After forming, it is sent to an oven at a temperature of 120℃ for 15 min. After curing, the film material is cooled by a 30℃ cooling roller and then wound up by a winding machine with the winding tension controlled at 8 N to obtain the film material. S3. Using a micro-grooving method, solvent-free acrylic pressure-sensitive adhesive is uniformly coated on one side of the film material, controlling the adhesive layer thickness to 15 μm. Immediately after coating, a polyethylene release film is placed on the adhesive surface, and the film is pressed by a composite roller at a pressure of 0.5 MPa and a temperature of 50°C. After pressing, the film is placed in a constant temperature and humidity environment at a temperature of 25°C and a humidity of 50% for 24 hours to finally obtain a nano-tungsten oxide solar film.

[0039] Comparative Example 1: An equal amount of unmodified polyethylene terephthalate was used, and the remaining components and processes were the same as in Example 1.

[0040] Comparative Example 2: No nano-tungsten oxide was added; the remaining components and processes were the same as in Example 1.

[0041] Comparative Example 3: An equal amount of unmodified polyethylene terephthalate and no nano-tungsten oxide were added; the remaining components and processes were the same as in Example 1.

[0042] Performance testing: 1. Sample size: Visible light transmittance / near-infrared blocking rate / water contact angle / fouling resistance: 50 mm × 50 mm; Tensile strength / elongation at break: 150 mm × 15 mm; UV aging resistance (500h): 70 mm × 150 mm; 2. Test items: Visible light transmittance (%), near-infrared blocking rate (%): Refer to standard GB / T 2680-2021; Water contact angle (°), antifouling rating: Refer to standard GB / T 30693-2014; Tensile strength (MPa), elongation at break (%): Refer to standard GB / T 1040.3-2006; UV aging resistance (500h): Refer to standard GB / T 16422.3-2022, test yellowing index, near-infrared blocking rate retention rate and tensile strength retention rate; Table 1 Table 2 As shown in the table above, the near-infrared blocking rates of Examples 1-3 were 89.3-92.1%, while those of Comparative Examples 1-3 were 34.2-62.4%, indicating that modified polyethylene terephthalate and the addition of nano-tungsten oxide can effectively improve the thermal insulation performance. The water contact angles of Examples 1-3 were 108.5-115.7°, with antifouling grades of 4-5. Comparative Example 1 had a water contact angle of 72.6°, with an antifouling grade of 2. Comparative Example 3 had a water contact angle of 71.8°, with an antifouling grade of 2. Comparative Example 2 was similar to Examples 1-3, indicating that modified polyethylene terephthalate can improve the hydrophobicity of the membrane surface and enhance antifouling performance. The tensile strength of Comparative Examples 1-3 was 68.5-75.1 MPa, and the elongation at break was 185-203%. Comparative Examples 1 and 3 were lower than those of Examples 1-3, while Comparative Example 2 was similar to the Examples, indicating that modified polyethylene terephthalate can improve mechanical properties. Examples 1-3 showed better aging resistance, while Comparative Examples 1-3 showed poorer aging resistance.

[0043] 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 nano-tungsten oxide solar film, characterized in that, The solar film consists of a film material, an adhesive, and a protective film. The adhesive is applied to one side of the film material, and the protective film covers the surface of the adhesive. Membrane material: made from the following raw materials in parts by weight: 60-80 parts modified polyethylene terephthalate, 5-10 parts nano tungsten oxide, 2-5 parts mica functional filler, 3-8 parts film-forming aid, 0.5-1.5 parts defoamer, 0.1-0.5 parts ultraviolet absorber, 0.2-0.8 parts antioxidant, and 30-60 parts solvent; Adhesive: Solvent-free acrylic pressure-sensitive adhesive; Protective film: Polyethylene release film.

2. The nano-tungsten oxide solar film according to claim 1, characterized in that, The preparation method of modified polyethylene terephthalate includes the following steps: A1. Add 3-8 parts of graphite to 50-80 parts of 70-75% ethanol aqueous solution, adjust the pH to 3-4 with glacial acetic acid, add 0.3-0.8 parts of γ-aminopropyltriethoxysilane, heat to 60-70℃, keep warm and stir for 1-2 h, filter, wash 1-3 times with anhydrous ethanol, and dry at 80-100℃ for 4-6 h to obtain activated graphite; A2. Using a twin-screw extruder, add 100-120 parts of polyethylene terephthalate and 5-8 parts of glycidyl methacrylate through the main feed port, add activated graphite through the side feed port, and add 3-6 parts of modifier and 0.05-0.1 parts of tetrabutyl titanate through the liquid feed port. Melt-blend in the extruder, extrude through a die, water-cool, pelletize, and dry at 100-120℃ for 2-4 hours to obtain modified polyethylene terephthalate.

3. The nano-tungsten oxide solar film according to claim 2, characterized in that, In step A2, the parameters of the twin-screw extruder are set as follows: screw temperature: zone 1 220~240℃, zone 2 250~255℃, zone 3 260~280℃, die head 245~255℃, screw speed 200~250 r / min.

4. The nano-tungsten oxide solar film according to claim 2, characterized in that, The preparation method of the modifier in step A2 includes the following steps: B1. Add 10-20 parts of methyltrichlorosilane and 120-200 parts of anhydrous tetrahydrofuran to the flask, stir and cool to -10 to 0°C, slowly add 60-90 parts of a 10-15% tetrahydrofuran solution of 3,3,3-trifluoropropylmagnesium chloride, after the addition is complete, raise the temperature to 25-30°C, keep warm and stir for 4-6 hours; B2. Add 3-5 parts of anhydrous zinc chloride to the above reaction solution, stir and activate for 10-15 min, then slowly add 10-15 parts of 3-chloropropanol, heat to reflux temperature, and keep the reaction at this temperature for 8-10 h. B3. Slowly pour the reaction solution into 100-150 parts of a 10-20% ammonium chloride aqueous solution, stir for 10-30 min, allow to stand and separate into layers, collect the upper organic phase, wash the organic phase with deionized water until neutral, add 5-10 parts of anhydrous magnesium sulfate to the organic phase, stir and dry at room temperature for 10-12 h, filter to remove the desiccant, transfer the filtrate to a vacuum distillation apparatus, control the vacuum degree to 10-20 Pa and the distillation temperature to 120-130℃, collect the fraction to obtain the modifier.

5. The nano-tungsten oxide solar film according to claim 1, characterized in that, The nano-tungsten oxide particles have a diameter of 10~50 nm, and the mica functional filler particles have a diameter of 1500~2000 mesh.

6. The nano-tungsten oxide solar film according to claim 1, characterized in that, The film-forming aid is one of alcohol ester-12 and ethylene glycol butyl ether; the defoamer is one of defoamer BYK-052, defoamer DF-100, and defoamer GP-330; the ultraviolet absorber is one of UV-327, UV-P, and UV-531; the antioxidant is one of antioxidant 1010, antioxidant 168, and antioxidant DLTP; and the solvent is one of propylene glycol methyl ether acetate, ethyl acetate, and N,N-dimethylformamide.

7. The nano-tungsten oxide solar film according to claim 1, characterized in that, The solvent-free acrylate pressure-sensitive adhesive has a viscosity of 200~400 cP, and the polyethylene release film is made of low-density polyethylene with a thickness of 25~50 μm.

8. A method for preparing a nano-tungsten oxide solar film according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Add solvent to the reactor, start stirring at 600~800 r / min, slowly add modified polyethylene terephthalate, heat to 60~80℃, keep stirring for 1~2 h, cool to 50~55℃, add nano tungsten oxide and mica functional filler, stir at 1200~1500 r / min for 10~20 min, cool to room temperature, add film-forming aid, ultraviolet absorber and antioxidant in sequence, stir at 600~800 r / min for 10~20 min, then grind in a sand mill, add defoamer, stir at 300~500 r / min for 10~15 min, vacuum degas at -0.09~-0.095 MPa for 10~20 min to obtain composite slurry; S2. Select a single-screw casting machine with a die width of 1.2~1.5 m and a die gap of 80~120 μm. The composite slurry is evenly conveyed to the casting machine die at a conveying pressure of 0.3~0.5 MPa. The slurry is evenly spread on the preheated conveyor belt through the die to form a continuous and uniform wet film. After forming, it is sent to an oven at a temperature of 100~120℃ for 10~15 min. After curing, the film is cooled by a cooling roller at 25~30℃ and then wound up by a winding machine with a winding tension controlled at 5~8 N to obtain the film material. S3. Using a micro-grooving coating method, solvent-free acrylic pressure-sensitive adhesive is uniformly coated on one side of the film material, controlling the adhesive layer thickness to be 10~15 μm. Immediately after coating, a polyethylene release film is placed on the adhesive surface, and the film is pressed by a composite roller at a pressure of 0.3~0.5 MPa and a temperature of 40~50℃. After pressing, the film is placed in a constant temperature and humidity environment at a temperature of 22~25℃ and a humidity of 40~50% for 12~24 hours to finally obtain a nano-tungsten oxide solar film.

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