Thermal insulation functional powder, master batch, preparation method and application thereof

Abstract

This invention discloses a thermal insulation functional powder, masterbatch, its preparation method, and its applications, relating to the field of polymer materials technology. The thermal insulation functional powder with excellent dispersibility provided by this invention employs an indium tin antimony zinc multi-doped system and is prepared through a sol-gel-in-situ modification process, combined with stepwise pH control, γ-aminopropyltriethoxysilane surface modification, supercritical carbon dioxide drying, and low-temperature heat treatment, resulting in a particle size of 5-50 nm. This powder can be used to prepare thermal insulation slurries; it can also be further granulated with plastic chips and additives to obtain thermal insulation masterbatches; the obtained masterbatches can be blended with modified silica, antioxidants, etc., to form highly transparent, highly thermally insulating, and highly weather-resistant functional films suitable for construction, automotive, and other fields.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a heat-insulating functional powder, masterbatch, its preparation method, and its application. Background Technology

[0002] With the intensifying trend of global warming and the increasing frequency of extreme heat events, the development of high-efficiency thermal insulation materials has become a key technological requirement for temperature control and energy conservation and emission reduction in fields such as construction, automotive, agriculture, and energy. Among various thermal insulation materials, transparent thermal insulation functional materials based on nanoparticles have attracted much attention due to their ability to selectively block near-infrared radiation while maintaining high visible light transmittance. Currently, this technological field mainly faces the following technical challenges and development difficulties:

[0003] Inherent limitations of mainstream materials: Cesium tungsten bronze nanoparticles, as a current mainstream thermal insulation material, exhibit excellent shielding performance in the near-infrared region due to their localized surface plasmon resonance effect. However, the material's inherent blue-purple appearance and obvious photochromic / electrochromic effect severely limit its application in high-end building curtain walls, automotive windows, and scenarios with high color rendering requirements.

[0004] Limitations of alternative material preparation processes: To address the color issue of cesium tungsten bronze, researchers have turned to developing tungsten-free thermal insulating nanoparticles such as indium tin oxide and antimony-doped tin oxide. However, these materials are typically prepared using a co-precipitation-high-temperature calcination method, which is prone to severe particle sintering, hard agglomeration, and abnormal grain growth during high-temperature processing above 500°C. This disrupts the nanoscale effect, resulting in poor product dispersibility, increased haze, and ultimately affecting the film's transparency and thermal insulation performance.

[0005] Functional integration and durability challenges: Existing technologies struggle to simultaneously achieve a balance between high infrared blocking rate, high visible light transmittance, low haze, and excellent weather resistance. Furthermore, the dispersion stability of nanoparticles in polymer matrices and performance degradation during long-term use remain key factors restricting their commercial application.

[0006] In summary, there is an urgent need in this field to develop a low-temperature synthesis technology for heat-insulating nanoparticles that can suppress agglomeration at the source, have both high infrared blocking rate and high light transmittance, and have no coloring problems, and to build a series of application products with balanced performance and simple process based on this technology. Summary of the Invention

[0007] The purpose of this invention is to provide a thermal insulation functional powder, masterbatch, its preparation method, and its application, to solve the problems mentioned in the background art, such as the inherent blue-purple hue, photochromic / electrochromic effect, hard agglomeration caused by high-temperature calcination, poor dispersibility, and the difficulty in simultaneously achieving film transparency and thermal insulation. This invention uses a sol-gel-in-situ modification method combined with supercritical fluid drying and low-temperature heat treatment to prepare a thermal insulation functional powder with small particle size, uniform dispersion, and stable performance. This powder is further applied to masterbatches, slurries, and films to achieve comprehensive performance of high transparency, high thermal insulation, high clarity, and high weather resistance.

[0008] In a first aspect, the present invention provides a method for preparing a heat-insulating functional powder, specifically comprising the following steps:

[0009] A1. By weight, dissolve 60-70 parts of tin source, 5-10 parts of indium source, 1-5 parts of antimony source, and 0.1-2 parts of zinc source in a mixed solvent of 500-1000 parts of ethanol and water to obtain a mixed solution.

[0010] The volume ratio of ethanol to water in the ethanol-water mixture is 4:1.

[0011] The total concentration of metal ions in the mixed solution is 0.2-0.5 mol / L;

[0012] A2. Add 75-90 parts of citric acid to the mixed solution obtained in step A1, stir at 55-65℃ for 1-3 hours, raise the temperature to 70-75℃, add 5% ammonia solution dropwise under vigorous stirring until the pH reaches 2.5-3, continue stirring for 3-6 hours, slowly add 5% ammonia solution dropwise at a rate of 0.5-1 mL / min, adjust the pH to 6.5-7, stop heating, let stand at room temperature for 24-48 hours, remove the supernatant, add 300-500 parts of ethanol and soak for 8-12 hours, add 60-120 parts of 5% ethanol solution of γ-aminopropyltriethoxysilane, stir at 60-65℃ for 4-6 hours to obtain the primary slurry;

[0013] A3. Centrifuge the primary slurry obtained in step A2, wash the precipitate obtained by centrifugation with ethanol multiple times, dry it in supercritical carbon dioxide fluid at 10-15 MPa for 2-4 hours to obtain the primary product, and heat treat it at 200-300℃ for 5-10 hours under a nitrogen atmosphere to obtain the heat-insulating powder.

[0014] As a preferred embodiment of the present invention, the tin source in step A1 is selected from one or more of tin tetrachloride and tin nitrate; the indium source is selected from one or more of indium trichloride, indium nitrate, and indium acetate; the antimony source is selected from one or more of antimony trichloride and antimony nitrate; and the zinc source is selected from one or more of zinc chloride, zinc nitrate, and zinc acetate.

[0015] It should be noted that this invention achieves uniform mixing and surface modification of metal ions in a liquid system through a sol-gel in-situ modification method. Citric acid, as a complexing agent, forms stable complexes with metal ions, preventing premature precipitation and ensuring uniform composition of nanoparticles. Precise pH control is performed in two steps: first, hydrolysis and condensation are promoted under acidic conditions to form a sol; then, the pH is slowly adjusted to near neutral to induce gelation and prevent rapid particle aggregation. γ-aminopropyltriethoxysilane, as a surface modifier, reacts with hydroxyl groups on the particle surface through silane hydrolysis to form an organic coating layer, effectively preventing nanoparticle aggregation. Supercritical carbon dioxide drying utilizes its zero surface tension characteristic to remove the solvent without damaging the gel network structure, obtaining fluffy, non-agglomerated nanoparticle powder. Low-temperature heat treatment is carried out under nitrogen protection, which promotes the entry of dopant ions (such as indium, antimony, and zinc) into the tin oxide lattice, providing free electrons to enhance near-infrared shielding performance, while avoiding hard agglomeration and grain growth caused by high-temperature sintering, thus maintaining the functional effects at the nanoscale.

[0016] In a second aspect, the present invention provides a heat-insulating functional powder prepared by the preparation method described in the first aspect, having a particle size of 5-50 nm.

[0017] It should be noted that this powder uses tin oxide as a matrix and forms a defect-type semiconductor structure through doping with indium, antimony, and zinc. Free electrons selectively absorb and reflect near-infrared light through localized surface plasmon resonance, achieving highly efficient heat insulation. Simultaneously, the nanoscale particle size and surface organic modification layer ensure uniform dispersion in polymer matrices or solvents, avoiding increased haze and performance degradation caused by agglomeration, resulting in high transparency and excellent dispersion stability.

[0018] A third aspect of the present invention provides an application of a heat-insulating functional powder, the specific steps of which are as follows:

[0019] The heat-insulating functional powder prepared by the method described in the fourth aspect is applied to the preparation of the heat-insulating functional slurry. By weight, 0.1-2 parts of dispersant are added to 68-94.9 parts of solvent, stirred to form a homogeneous solution, 5-30 parts of heat-insulating functional powder are added, stirred for 1-2 hours, ultrasonically treated for 1-2 hours, and then ball-milled for 1-3 hours. The heat-insulating functional slurry is obtained by filtration through a 0.2 μm nylon filter membrane.

[0020] As a preferred embodiment of the present invention, the dispersant is any one or more of polyvinylpyrrolidone, polyethylene glycol, and polyoxyethylene ether;

[0021] As a preferred embodiment of the present invention, the solvent is any one or more of ethanol, isopropanol, ethyl acetate, butyl acetate, toluene, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and ethylene glycol butyl ether acetate.

[0022] It should be noted that, as a functional filler, the small particle size and good dispersibility of this powder make it easy to combine with various resins and solvents to form a uniform functional system. In slurry, the powder can be stably dispersed in organic solvents and used for coating to prepare transparent heat-insulating coatings.

[0023] A fourth aspect of the present invention provides a method for preparing a heat-insulating masterbatch, specifically comprising the following steps:

[0024] B1. Provide a heat-insulating functional powder prepared by the method described in the first aspect;

[0025] B2. By weight, mix 1-20 parts of heat-insulating functional powder, 0.1-2 parts of additives and 78-98.9 parts of plastic chips to obtain a mixture.

[0026] The additive is any one or more of titanate coupling agent, pentaerythritol stearate, and isopropyl triphenyl phosphate;

[0027] The plastic chips are any one or more of polyethylene terephthalate, polybutylene terephthalate, polyvinyl butyral, polycarbonate, polymethacrylate, polypropylene, and polyvinyl chloride;

[0028] B3. The mixture obtained in B2 is melt-blended and extruded into granules using a plastic granulator to obtain heat-insulating masterbatch.

[0029] It should be noted that during the masterbatch preparation process, the additives act as a bridge, improving interfacial compatibility and preventing powder agglomeration or sedimentation during melt processing. The high shear force of the plastic granulator further promotes powder dispersion, forming a uniform functional phase. Pre-dispersing the nano-functional particles in masterbatch form facilitates subsequent film processing, improving production efficiency and product consistency.

[0030] In a fifth aspect, the present invention provides a heat-insulating functional masterbatch prepared by the preparation method described in the fourth aspect, which can be used to prepare heat-insulating functional products by extrusion, blow molding or casting.

[0031] It should be noted that the content of functional particles in this masterbatch is controllable, and due to the nanoscale and surface modification of the powder, it is uniformly distributed in the matrix, having minimal impact on the matrix's transparency and mechanical properties. The masterbatch form facilitates storage, transportation, and processing, making it suitable for large-scale industrial production.

[0032] In a sixth aspect, the present invention provides a method for preparing a heat-insulating film, the specific steps of which are as follows:

[0033] The heat-insulating functional masterbatch prepared by the method described in the fourth aspect is applied to the preparation of the heat-insulating functional film. By weight, 5-30 parts of the heat-insulating functional masterbatch are blended with 0.1-0.5 parts of modified silica, 0.05-0.3 parts of antioxidant, 0.05-0.3 parts of light stabilizer and 68.9-94.8 parts of plastic chips. The mixture is then melt-extruded, biaxially stretched, cooled and wound up to obtain a heat-insulating functional film with a thickness of 10-100 μm.

[0034] The modified silica is prepared as follows:

[0035] C1. Disperse 10-15 parts of hollow mesoporous silica in 100-150 parts of anhydrous ethanol and disperse for 1-3 hours with stirring at 1000-1500 rpm. Add 0.5-1.5 parts of silane coupling agent containing epoxy groups and reflux at 65-75℃ for 2-4 hours under nitrogen protection.

[0036] The hollow mesoporous silica has a pore size of 2-10 nm and a specific surface area of ​​300-500 m². 2 / g;

[0037] The silane coupling agent containing epoxy groups is one or both of 3-(2,3-epoxypropoxy)propyltrimethoxysilane or 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane.

[0038] C2. Cool the reaction system to 30-40℃, add 1-3 parts of terminal amino hyperbranched polyamide, and program the temperature to 80-90℃ at a rate of 0.5-1℃ / min. Stir continuously for 3-5 hours, centrifuge, wash with N,N-dimethylformamide and ethanol alternately 2-3 times each, and dry under vacuum at 70-80℃ for 8-12 hours to obtain modified silica.

[0039] As a preferred embodiment of the present invention, the antioxidant is any one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant 626, antioxidant 1098, and antioxidant PEPQ.

[0040] As a preferred embodiment of the present invention, the light stabilizer is any one or more of UV-327, UV-1577, UV-944, and UV-770.

[0041] It should be noted that the biaxial stretching process optimizes molecular orientation, enhancing the mechanical strength and dimensional stability of the film. The final film exhibits a visible light transmittance of over 70% at 550nm, an infrared blocking rate exceeding 93% at 1400nm, and a haze of less than 1%. Furthermore, it shows no significant performance changes after 500 hours of UV aging testing, demonstrating excellent overall performance and suitability for applications such as automotive window films, architectural glass films, and agricultural greenhouse coverings.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) Through an innovative indium tin antimony zinc multi-doping system and sol-gel-in-situ modification process, a heat-insulating functional powder without blue-purple tint and photo / electrochromic effects was successfully prepared. While maintaining high near-infrared blocking rate, the visible light transmittance was improved, which improved the application limitations of traditional materials such as cesium tungsten bronze in high-end display, building lighting and other fields, and improved the optical defects of traditional heat-insulating materials.

[0044] (2) A stable nano-dispersion system was constructed by stepwise pH control combined with supercritical fluid drying technology. Through in-situ modification with γ-aminopropyltriethoxysilane and supercritical CO2 drying, the hard agglomeration of nanoparticles was effectively suppressed, and the obtained powder particle size was controlled within the range of 5-50 nm with uniform particle size distribution. This improved the particle sintering and performance degradation problems caused by traditional high-temperature calcination methods and improved the nanoparticle agglomeration problem.

[0045] (3) Introducing modified silica with a core-shell structure into the thin film system, in which the hollow mesoporous core can enhance infrared scattering, and the surface-grafted hyperbranched polymer provides a three-dimensional interface layer, which has a synergistic effect with the heat insulation masterbatch, so that the film can maintain high transparency while having excellent heat insulation performance, mechanical strength and weather resistance, achieving the optimal balance of multiple performance parameters and a breakthrough in comprehensive performance. Detailed Implementation

[0046] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0047] Preparation Example 1

[0048] The preparation method of modified silica is as follows:

[0049] C1. Disperse 12 parts of hollow mesoporous silica in 120 parts of anhydrous ethanol and disperse for 2 hours under stirring at 1200 rpm. Add 0.8 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and reflux at 70°C for 3 hours under nitrogen protection.

[0050] The hollow mesoporous silica has an average pore size of 5.5 nm and an average specific surface area of ​​400 m². 2 / g;

[0051] C2. Cool the reaction system to 35°C, add 2 parts of terminal amino hyperbranched polyamide, and program the temperature to 85°C at a rate of 0.8°C / min. Stir continuously for 4 hours, centrifuge, wash with N,N-dimethylformamide and ethanol alternately 3 times each, and dry under vacuum at 75°C for 10 hours to obtain modified silica.

[0052] Example 1

[0053] The preparation method of heat-insulating functional powder specifically includes the following steps:

[0054] A1. By weight, dissolve 65 parts tin tetrachloride, 7.5 parts indium trichloride, 3 parts antimony trichloride, and 1 part zinc chloride in a mixed solvent of 800 parts ethanol and water in a volume ratio of 4:1 to obtain a mixed solution.

[0055] A2. Add 83 parts of citric acid to the mixed solution obtained in step A1, stir at 60℃ for 2 hours, raise the temperature to 70℃, add 5% ammonia solution dropwise under vigorous stirring until the pH reaches 2.8, continue stirring for 4.5 hours, slowly add 5% ammonia solution dropwise at a rate of 0.8 mL / min, adjust the pH to 6.8, stop heating, let stand at room temperature for 36 hours, remove the supernatant, add 400 parts of ethanol and soak for 10 hours, add 90 parts of 5% ethanol solution of γ-aminopropyltriethoxysilane, stir at 60℃ for 5 hours to obtain the primary slurry;

[0056] A3. The primary slurry obtained in step A2 is separated by centrifugation and washed multiple times with ethanol. It is then dried in a supercritical carbon dioxide fluid at 12 MPa for 3 hours to obtain the primary product. The primary product is then heat-treated at 250°C for 8 hours under a nitrogen atmosphere to obtain the heat-insulating powder.

[0057] Example 2

[0058] The specific steps for preparing heat-insulating functional powders are as follows:

[0059] A1. By weight, dissolve 70 parts tin tetrachloride, 10 parts indium trichloride, 5 parts antimony trichloride, and 2 parts zinc chloride in a mixed solvent of 850 parts ethanol and water in a volume ratio of 4:1 to obtain a mixed solution.

[0060] A2. Add 90 parts of citric acid to the mixed solution obtained in step A1, stir at 60℃ for 2 hours, raise the temperature to 70℃, add 5% ammonia solution dropwise under vigorous stirring until the pH reaches 2.8, continue stirring for 4.5 hours, slowly add 5% ammonia solution dropwise at a rate of 0.8 mL / min, adjust the pH to 6.8, stop heating, let stand at room temperature for 36 hours, remove the supernatant, add 400 parts of ethanol and soak for 10 hours, add 90 parts of 5% ethanol solution of γ-aminopropyltriethoxysilane, stir at 60℃ for 5 hours to obtain the primary slurry;

[0061] A3. The primary slurry obtained in step A2 is separated by centrifugation and washed multiple times with ethanol. It is then dried in a supercritical carbon dioxide fluid at 12 MPa for 3 hours to obtain the primary product. The primary product is then heat-treated at 250°C for 8 hours under a nitrogen atmosphere to obtain the heat-insulating powder.

[0062] Example 3

[0063] The specific steps for preparing heat-insulating functional powders are as follows:

[0064] A1. By weight, dissolve 65 parts tin tetrachloride, 7.5 parts indium trichloride, 3 parts antimony trichloride, and 1 part zinc chloride in a mixed solvent of 750 parts ethanol and water in a volume ratio of 4:1 to obtain a mixed solution.

[0065] A2. Add 83 parts of citric acid to the mixed solution obtained in step A1, stir at 60℃ for 2 hours, raise the temperature to 70℃, add 5% ammonia solution dropwise under vigorous stirring until the pH reaches 2.8, continue stirring for 4.5 hours, slowly add 5% ammonia solution dropwise at a rate of 0.8 mL / min, adjust the pH to 6.8, stop heating, let stand at room temperature for 36 hours, remove the supernatant, add 400 parts of ethanol and soak for 10 hours, add 90 parts of 5% ethanol solution of γ-aminopropyltriethoxysilane, stir at 60℃ for 5 hours to obtain the primary slurry;

[0066] A3. The primary slurry obtained in step A2 is separated by centrifugation and washed multiple times with ethanol. It is then dried in a supercritical carbon dioxide fluid at 12 MPa for 3 hours to obtain the primary product. The primary product is then heat-treated at 250°C for 8 hours under a nitrogen atmosphere to obtain the heat-insulating powder.

[0067] Example 4

[0068] The preparation steps of the heat-insulating slurry are as follows:

[0069] By weight, 1.5 parts of polyvinylpyrrolidone were added to 85 parts of ethyl acetate and stirred to form a homogeneous solution. Then, 24 parts of the heat-insulating functional powder prepared in Example 1 were added, stirred for 2 hours, ultrasonically treated for 1 hour, and then ball-milled for 2 hours. The mixture was then filtered through a 0.2 μm nylon filter membrane to obtain the heat-insulating functional slurry.

[0070] Example 5

[0071] The preparation steps of the thermal insulation slurry, by weight, are as follows:

[0072] One part of polyvinylpyrrolidone was added to 76 parts of ethyl acetate and stirred to form a homogeneous solution. Then, 20 parts of the heat-insulating functional powder prepared in Example 1 were added, stirred for 2 hours, ultrasonically treated for 1 hour, and then ball-milled for 2 hours. The mixture was then filtered through a 0.2 μm nylon filter membrane to obtain the heat-insulating functional slurry.

[0073] Example 6

[0074] The preparation steps of the heat-insulating slurry are as follows:

[0075] By weight, 2 parts of polyvinylpyrrolidone were added to 94 parts of ethyl acetate and stirred to form a homogeneous solution. Then, 28 parts of the heat-insulating functional powder prepared in Example 1 were added, stirred for 2 hours, ultrasonically treated for 1 hour, and then ball-milled for 2 hours. The mixture was then filtered through a 0.2 μm nylon filter membrane to obtain the heat-insulating functional slurry.

[0076] Example 7

[0077] The preparation steps of the heat insulation masterbatch are as follows:

[0078] By weight, 10 parts of the heat-insulating functional powder prepared in Example 1, 1 part of titanate coupling agent and 88 parts of polyethylene terephthalate chips were mixed to obtain a mixture. The mixture was then melt-blended and extruded into granules using a plastic granulator to obtain a heat-insulating functional masterbatch.

[0079] The preparation steps of the heat-insulating film are as follows:

[0080] By weight, 20 parts of heat-insulating masterbatch were blended with 0.3 parts of modified silica, 0.2 parts of antioxidant, 0.2 parts of light stabilizer, and 85 parts of polyethylene terephthalate chips. The blend was fed into a twin-screw extruder with the following temperature parameters set: feeding section 210℃, compression section 240℃, homogenization section 255℃, melting section 260℃, mixing section 270℃, and die section 265℃. The screw speed was maintained at 200 rpm, and the melt pressure was maintained at 3.5 MPa to obtain molten material. The molten material was then passed through... The film is extruded through a T-die, with the temperature of the film controlled at 100℃. It then enters the biaxial stretching process, where it is first heated to 100℃ by infrared and then stretched longitudinally with a stretch ratio of 3. Next, it enters the transverse stretching section and is stretched transversely at a slightly higher temperature with a stretch ratio of 3.5. After biaxial stretching, the film enters the heat setting zone and undergoes heat relaxation treatment at 200℃. It is then rapidly cooled and set by a cooling roller at 25℃. Under constant tension control, it is wound into a film at a speed of 20m / min to obtain a heat-insulating film with a thickness of 50μm.

[0081] Some of the raw materials involved in this embodiment are substances obtained from Preparation Example 1.

[0082] Example 8

[0083] The preparation steps of the heat-insulating film are as follows:

[0084] By weight, 24 parts of the heat-insulating masterbatch prepared in Example 7 were blended with 0.4 parts of modified silica, 0.25 parts of antioxidant, 0.25 parts of light stabilizer, and 880 parts of polyethylene terephthalate chips. The blend was fed into a twin-screw extruder with the following specific temperature parameters: feeding section 210°C, compression section 240°C, homogenization section 255°C, melting section 260°C, mixing section 270°C, and die section 265°C. The screw speed was maintained at 200 rpm, and the melt pressure was maintained at 3.5 MPa to obtain the molten material. The molten material is extruded into a casting through a T-die, with the casting temperature controlled at 100℃. It then enters the biaxial stretching process, first being heated to 100℃ by infrared and then longitudinally stretched with a stretching ratio of 3. Next, it enters the transverse stretching section and is stretched laterally at a slightly higher temperature with a stretching ratio of 3.5. After biaxial stretching, the film enters the heat setting zone and undergoes heat relaxation treatment at 200℃. Subsequently, it is rapidly cooled and set by a cooling roller at 25℃. Under constant tension control, it is wound into a film at a speed of 20m / min to obtain a heat-insulating functional film with a thickness of 50μm.

[0085] Some of the raw materials involved in this embodiment are substances obtained from Preparation Example 1.

[0086] Example 9

[0087] The preparation steps of the heat-insulating film are as follows:

[0088] By weight, 16 parts of the heat-insulating masterbatch prepared in Example 7 were blended with 0.2 parts of modified silica, 0.15 parts of antioxidant, 0.15 parts of light stabilizer, and 75 parts of polyethylene terephthalate chips. The blend was fed into a twin-screw extruder with the following specific temperature parameters: feeding section 210°C, compression section 240°C, homogenization section 255°C, melting section 260°C, mixing section 270°C, and die section 265°C. The screw speed was maintained at 200 rpm, and the melt pressure was maintained at 3.5 MPa to obtain the molten material. The molten material is extruded into a casting through a T-die, with the casting temperature controlled at 100℃. It then enters the biaxial stretching process, first being heated to 100℃ by infrared and then longitudinally stretched with a stretching ratio of 3. Next, it enters the transverse stretching section and is stretched laterally at a slightly higher temperature with a stretching ratio of 3.5. After biaxial stretching, the film enters the heat setting zone and undergoes heat relaxation treatment at 200℃. Subsequently, it is rapidly cooled and set by a cooling roller at 25℃. Under constant tension control, it is wound into a film at a speed of 20m / min to obtain a heat-insulating functional film with a thickness of 50μm.

[0089] Some of the raw materials involved in this embodiment are substances obtained from Preparation Example 1.

[0090] Comparative Example 1

[0091] The difference between this comparative example and Example 1 is that γ-aminopropyltriethoxysilane was not used for surface modification, while the remaining steps and parameters are the same as in Example 1.

[0092] Comparative Example 2

[0093] The difference between this comparative example and Example 1 is that conventional vacuum drying (80°C, 12h) is used instead of supercritical carbon dioxide fluid drying in step A3, while the remaining steps and parameters are the same as in Example 1.

[0094] Comparative Example 3

[0095] The difference between this comparative example and Example 1 is that the low-temperature heat treatment is replaced with a traditional high-temperature calcination process (550°C, 2 hours, air atmosphere), while the remaining steps and parameters are the same as in Example 1.

[0096] Comparative Example 4

[0097] The preparation steps of the heat-insulating slurry are as follows:

[0098] By weight, 1.5 parts of polyvinylpyrrolidone were added to 85 parts of ethyl acetate and stirred to form a homogeneous solution. Then, 24 parts of the heat-insulating functional powder prepared in Comparative Example 1 were added, stirred for 2 hours, ultrasonically treated for 1 hour, and then ball-milled for 2 hours. The mixture was then filtered through a 0.2 μm nylon filter membrane to obtain the heat-insulating functional slurry.

[0099] Comparative Example 5

[0100] The preparation steps of the heat-insulating slurry are as follows:

[0101] By weight, 1.5 parts of polyvinylpyrrolidone were added to 85 parts of ethyl acetate and stirred to form a homogeneous solution. Then, 24 parts of the heat-insulating functional powder prepared in Comparative Example 2 were added, stirred for 2 hours, ultrasonically treated for 1 hour, and then ball-milled for 2 hours. The mixture was then filtered through a 0.2 μm nylon filter membrane to obtain the heat-insulating functional slurry.

[0102] Comparative Example 6

[0103] The preparation steps of the heat-insulating slurry are as follows:

[0104] By weight, 1.5 parts of polyvinylpyrrolidone were added to 85 parts of ethyl acetate and stirred to form a homogeneous solution. Then, 24 parts of the heat-insulating functional powder prepared in Comparative Example 3 were added, stirred for 2 hours, ultrasonically treated for 1 hour, and then ball-milled for 2 hours. The mixture was then filtered through a 0.2 μm nylon filter membrane to obtain the heat-insulating functional slurry.

[0105] Comparative Example 7

[0106] The preparation steps of the heat insulation masterbatch are as follows:

[0107] By weight, 10 parts of the heat-insulating functional powder prepared in Comparative Example 1, 1 part of titanate coupling agent and 88 parts of polyethylene terephthalate chips were mixed to obtain a mixture. The mixture was then melt-blended and extruded into granules using a plastic granulator to obtain a heat-insulating functional masterbatch.

[0108] The preparation steps of the heat-insulating film are as follows:

[0109] By weight, 20 parts of heat-insulating masterbatch were blended with 0.3 parts of modified silica, 0.2 parts of antioxidant, 0.2 parts of light stabilizer, and 85 parts of polyethylene terephthalate chips. The blend was fed into a twin-screw extruder with the following temperature parameters set: feeding section 210℃, compression section 240℃, homogenization section 255℃, melting section 260℃, mixing section 270℃, and die section 265℃. The screw speed was maintained at 200 rpm, and the melt pressure was maintained at 3.5 MPa to obtain molten material. The molten material was then passed through... The film is extruded through a T-die, with the temperature of the film controlled at 100℃. It then enters the biaxial stretching process, where it is first heated to 100℃ by infrared and then stretched longitudinally with a stretch ratio of 3. Next, it enters the transverse stretching section and is stretched transversely at a slightly higher temperature with a stretch ratio of 3.5. After biaxial stretching, the film enters the heat setting zone and undergoes heat relaxation treatment at 200℃. It is then rapidly cooled and set by a cooling roller at 25℃. Under constant tension control, it is wound into a film at a speed of 20m / min to obtain a heat-insulating film with a thickness of 50μm.

[0110] Comparative Example 8

[0111] The preparation steps of the heat insulation masterbatch are as follows:

[0112] By weight, 10 parts of the heat-insulating functional powder prepared in Comparative Example 2, 1 part of titanate coupling agent and 88 parts of polyethylene terephthalate chips were mixed to obtain a mixture. The mixture was then melt-blended and extruded into granules using a plastic granulator to obtain a heat-insulating functional masterbatch.

[0113] The preparation steps of the heat-insulating film are as follows:

[0114] By weight, 20 parts of heat-insulating masterbatch were blended with 0.3 parts of modified silica, 0.2 parts of antioxidant, 0.2 parts of light stabilizer, and 85 parts of polyethylene terephthalate chips. The blend was fed into a twin-screw extruder with the following temperature parameters set: feeding section 210℃, compression section 240℃, homogenization section 255℃, melting section 260℃, mixing section 270℃, and die section 265℃. The screw speed was maintained at 200 rpm, and the melt pressure was maintained at 3.5 MPa to obtain molten material. The molten material was then passed through... The film is extruded through a T-die, with the temperature of the film controlled at 100℃. It then enters the biaxial stretching process, where it is first heated to 100℃ by infrared and then stretched longitudinally with a stretch ratio of 3. Next, it enters the transverse stretching section and is stretched transversely at a slightly higher temperature with a stretch ratio of 3.5. After biaxial stretching, the film enters the heat setting zone and undergoes heat relaxation treatment at 200℃. It is then rapidly cooled and set by a cooling roller at 25℃. Under constant tension control, it is wound into a film at a speed of 20m / min to obtain a heat-insulating film with a thickness of 50μm.

[0115] Comparative Example 9

[0116] The preparation steps of the heat insulation masterbatch are as follows:

[0117] By weight, 10 parts of the heat-insulating functional powder prepared in Comparative Example 3, 1 part of titanate coupling agent and 88 parts of polyethylene terephthalate chips were mixed to obtain a mixture. The mixture was then melt-blended and extruded into granules using a plastic granulator to obtain a heat-insulating functional masterbatch.

[0118] The preparation steps of the heat-insulating film are as follows:

[0119] By weight, 20 parts of heat-insulating masterbatch were blended with 0.3 parts of modified silica, 0.2 parts of antioxidant, 0.2 parts of light stabilizer, and 85 parts of polyethylene terephthalate chips. The blend was fed into a twin-screw extruder with the following temperature parameters set: feeding section 210℃, compression section 240℃, homogenization section 255℃, melting section 260℃, mixing section 270℃, and die section 265℃. The screw speed was maintained at 200 rpm, and the melt pressure was maintained at 3.5 MPa to obtain molten material. The molten material was then passed through... The film is extruded through a T-die, with the temperature of the film controlled at 100℃. It then enters the biaxial stretching process, where it is first heated to 100℃ by infrared and then stretched longitudinally with a stretch ratio of 3. Next, it enters the transverse stretching section and is stretched transversely at a slightly higher temperature with a stretch ratio of 3.5. After biaxial stretching, the film enters the heat setting zone and undergoes heat relaxation treatment at 200℃. It is then rapidly cooled and set by a cooling roller at 25℃. Under constant tension control, it is wound into a film at a speed of 20m / min to obtain a heat-insulating film with a thickness of 50μm.

[0120] test:

[0121] I. Thermal Insulation Function Powder Performance Testing

[0122] 1. Particle size test: Tested using a laser particle size analyzer.

[0123] 2. Infrared blocking rate test: The powder was mixed with KBr and pressed into tablets, and the transmittance at 1400nm was measured using a Fourier transform infrared spectrometer.

[0124] 3. Specific surface area test: The BET nitrogen adsorption method was used for testing.

[0125] The test results are shown in Table 1.

[0126] Table 1: Test Results of Thermal Insulation Functional Powder Properties

[0127] Table 1

[0128]

[0129] II. Performance Testing of Thermal Insulation Slurry

[0130] 1. Stability test: Place the slurry in a 25℃ environment and let it stand for 30 days to observe whether it separates and settles.

[0131] 2. Viscosity test: A rotational viscometer was used for the test at a speed of 60 rpm.

[0132] 3. Dispersion test: The particle size distribution in the slurry was tested using a particle size analyzer.

[0133] The test results are shown in Table 2.

[0134] Table 2: Test Results of Thermal Insulation Slurry Performance

[0135] Table 2

[0136]

[0137] III. Performance Testing of Thermal Insulation Films

[0138] 1. Optical performance testing: The transmittance of visible light at 550 nm and the infrared blocking rate at 1400 nm were tested using an ultraviolet-visible-near-infrared spectrophotometer.

[0139] 2. Haze test: A haze meter is used for testing.

[0140] 3. Mechanical property testing: Tensile strength and elongation at break were tested using a universal testing machine.

[0141] 4. Weathering resistance test: A 500-hour ultraviolet aging test was conducted according to GB / T 16422.3, and the performance retention rate was calculated. The performance retention rate is divided into visible light transmittance retention rate and infrared blocking rate retention rate, and the calculation formulas are as follows:

[0142] Visible light transmittance retention rate = (Visible light transmittance of the aged sample at 550nm / Visible light transmittance of the unaged sample at 550nm) × 100%;

[0143] Infrared blocking rate retention rate = (Infrared blocking rate of the sample at 1400nm after aging / Infrared blocking rate of the sample at 1400nm before aging) × 100%;

[0144] The test results are shown in Table 3.

[0145] Table 3: Test Results of Thermal Insulation Film Performance

[0146] Table 3

[0147]

[0148] IV. Discussion of Results

[0149] As shown in Tables 1-3, the embodiments of the present invention are significantly superior to the comparative examples in terms of key performance indicators. Specifically:

[0150] In terms of powder performance: Compared with comparative examples 1-3, the heat insulation functional powders prepared in examples 1-3 have smaller average particle size and narrower particle size distribution, and have increased specific surface area and higher infrared blocking rate.

[0151] Regarding slurry stability: Compared to comparative examples 4-6, the slurries of examples 4-6 prepared based on the powders of examples 1-3 exhibited excellent storage stability, with a viscosity change rate of only 6%-7% over 30 days and no stratification.

[0152] Regarding the overall performance of the films: Compared to Comparative Examples 7-9, the films of Examples 7-9, prepared based on the slurries of Examples 4-6, maintain high transparency while exhibiting excellent optical properties, mechanical properties, and weather resistance. After 500 hours of UV aging testing, the visible light transmittance of the films in Examples 7-9 remained at over 98.8%, and the infrared blocking rate remained at over 98.5%, which are far superior to the comparative examples.

[0153] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0154] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the scope defined by the invention, and all such modifications and additions should fall within the protection scope of the present invention.

Claims

1. A method for preparing a heat-insulating functional powder, characterized in that: Includes the following steps: A1. By weight, dissolve 60-70 parts of tin source, 5-10 parts of indium source, 1-5 parts of antimony source, and 0.1-2 parts of zinc source in a mixed solvent of 500-1000 parts of ethanol and water to obtain a mixed solution. The volume ratio of ethanol to water in the ethanol-water mixture is 4:

1. The total concentration of metal ions in the mixed solution is 0.2-0.5 mol / L; A2. Add 75-90 parts of citric acid to the mixed solution obtained in step A1, stir at 55-65℃ for 1-3 hours, raise the temperature to 70-75℃, add 5% ammonia solution dropwise under vigorous stirring until the pH reaches 2.5-3, continue stirring for 3-6 hours, slowly add 5% ammonia solution dropwise at a rate of 0.5-1 mL / min, adjust the pH to 6.5-7, stop heating, let stand at room temperature for 24-48 hours, remove the supernatant, add 300-500 parts of ethanol and soak for 8-12 hours, add 60-120 parts of 5% ethanol solution of γ-aminopropyltriethoxysilane, stir at 60-65℃ for 4-6 hours to obtain the primary slurry; A3. Centrifuge the primary slurry obtained in step A2, wash the precipitate obtained by centrifugation with ethanol multiple times, dry it in supercritical carbon dioxide fluid at 10-15 MPa for 2-4 hours to obtain the primary product, and heat treat it at 200-300℃ for 5-10 hours under a nitrogen atmosphere to obtain the heat-insulating powder.

2. The method for preparing the heat-insulating functional powder according to claim 1, characterized in that: The tin source mentioned in step A1 is selected from one or more of tin tetrachloride and tin nitrate; the indium source is selected from one or more of indium trichloride, indium nitrate, and indium acetate; the antimony source is selected from one or more of antimony trichloride and antimony nitrate; and the zinc source is selected from one or more of zinc chloride, zinc nitrate, and zinc acetate.

3. A heat-insulating functional powder prepared by the method for preparing the heat-insulating functional powder as described in claim 1, characterized in that: The particle size of the heat-insulating powder is 5-50 nm.

4. An application of the heat-insulating functional powder according to claim 3, characterized in that: The heat-insulating functional powder is applied to the preparation of heat-insulating functional slurry. The specific preparation steps are as follows: By weight, add 0.1-2 parts of dispersant to 68-94.9 parts of solvent, stir to form a homogeneous solution, add 5-30 parts of heat-insulating functional powder, stir for 1-2 hours, ultrasonically treat for 1-2 hours, then ball mill and disperse, ball mill for 1-3 hours, and filter with a 0.2μm nylon filter membrane to obtain the heat-insulating functional slurry.

5. The application of the heat-insulating functional powder according to claim 4, characterized in that: The dispersant is any one or more of polyvinylpyrrolidone, polyethylene glycol, and polyoxyethylene ether; the solvent is any one or more of ethanol, isopropanol, ethyl acetate, butyl acetate, toluene, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and ethylene glycol butyl ether acetate.

6. A method for preparing a heat-insulating masterbatch, characterized in that: Includes the following steps: By weight, 1-20 parts of heat-insulating functional powder, 0.1-2 parts of additives and 78-98.9 parts of plastic chips are mixed to obtain a mixture. The mixture is then melt-blended and extruded into granules using a plastic granulator to obtain heat-insulating functional masterbatch. The heat-insulating functional powder is prepared according to the preparation method of the heat-insulating functional powder according to claim 1.

7. The method for preparing the heat-insulating masterbatch according to claim 6, characterized in that: The additive is any one or more of titanate coupling agent, pentaerythritol stearate, and isopropyl triphenyl phosphate; the plastic chip is any one or more of polyethylene terephthalate, polybutylene terephthalate, polyvinyl butyral, polycarbonate, polymethacrylate, polypropylene, and polyvinyl chloride.

8. A heat-insulating functional masterbatch prepared by the method for preparing the heat-insulating functional masterbatch as described in claim 6.

9. An application of the heat-insulating masterbatch according to claim 8, characterized in that: The heat-insulating masterbatch is applied to the preparation of heat-insulating films, and the specific preparation steps are as follows: By weight, 5-30 parts of heat-insulating functional masterbatch are blended with 0.1-0.5 parts of modified silica, 0.05-0.3 parts of antioxidant, 0.05-0.3 parts of light stabilizer and 68.9-94.8 parts of plastic chips, and then melt-extruded, biaxially stretched, cooled and wound up to obtain a heat-insulating functional film with a thickness of 10-100 μm. The modified silica is prepared as follows: C1. Disperse 10-15 parts of hollow mesoporous silica in 100-150 parts of anhydrous ethanol and disperse for 1-3 hours with stirring at 1000-1500 rpm. Add 0.5-1.5 parts of silane coupling agent containing epoxy groups and reflux at 65-75℃ for 2-4 hours under nitrogen protection. The hollow mesoporous silica has a pore size of 2-10 nm and a specific surface area of ​​300-500 m². 2 / g; The silane coupling agent containing epoxy groups is one or both of 3-(2,3-epoxypropoxy)propyltrimethoxysilane or 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane. C2. Cool the reaction system to 30-40℃, add 1-3 parts of terminal amino hyperbranched polyamide, and program the temperature to 80-90℃ at a rate of 0.5-1℃ / min. Stir continuously for 3-5 hours, centrifuge, wash with N,N-dimethylformamide and ethanol alternately 2-3 times each, and dry under vacuum at 70-80℃ for 8-12 hours to obtain modified silica.

10. The application of the heat-insulating masterbatch according to claim 9, characterized in that: The antioxidant is any one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant 626, antioxidant 1098, and antioxidant PEPQ; the light stabilizer is any one or more of UV-327, UV-1577, UV-944, and UV-770.

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