Lightweight thermal insulation textile coating based on hollow nanoparticles and preparation and application methods

Abstract

This proposal provides a lightweight thermal insulation textile coating based on hollow nanoparticles and a preparation and application method, including the formation of surface-modified inorganic hollow nanoparticles uniformly dispersed in an aqueous polymer matrix, wherein the inorganic hollow nanoparticles have a closed-pore structure, and the inner diameter of the inorganic hollow nanoparticles is 40 to 200 nm, the wall thickness is 2 to 12 nm, and the porosity is ≥70%. Monodisperse hollow nanoparticles are used to construct a uniform pore system, and based on the Knudzen effect, the free path of gas molecules is controlled in the nanopores, thereby achieving both nanoscale pore structure and excellent mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of functional textile materials, in particular to a lightweight thermal insulation textile coating based on hollow nanoparticles and a preparation and application method thereof, which can be widely used in the fields of clothing, home textiles, aerospace, and building insulation. Background Art

[0002] With the growing demand for lightweight, high-performance textiles in outdoor sports, smart homes, and industrial protection, textile materials with thermal insulation and heat preservation properties have become a research hotspot. Traditional thermal insulation materials (such as down and synthetic cotton) typically rely on increasing the material thickness or filling with high-density substances. However, such methods can easily increase the weight of the fabric and reduce its breathability, seriously affecting wearing comfort. To balance lightweight and thermal insulation performance, the industry has developed hollow cross-section fiber technology, which increases the thickness of the insulating air layer through a static air layer inside the fiber (dead air effect) and a surface raising process. However, this technology has significant drawbacks: excessive reliance on hollow fibers can lead to a decrease in the tensile strength of the fabric (mechanical loss rate can reach 30%-50%), and the surface is prone to whitening after friction, affecting the appearance and durability.

[0003] To address these issues, researchers have turned to the technology of constructing functional coatings on textile substrates. Because the thermal conductivity of air is extremely low (0.026 W / (m·K)), introducing pores into the coating becomes a key strategy for reducing heat conduction and achieving lightweighting. Existing technologies primarily achieve porosity through two methods:

[0004] 1. Foaming method: For example, US2007 / 0092688A1 uses polyurethane foam coating, and US3713868 uses acrylate-acrylonitrile copolymer foam to form a micron-sized pore structure through foaming.

[0005] 2. Hollow particle filling method: For example, 3M's hollow glass microspheres (particle size 1-100 microns) are widely used in coating systems (such as DE10003237A1, JP2007321304 and Chinese patent CN103397510A, etc.). By dispersing the microspheres in a matrix resin such as polyacrylate, a coating with both lightweight and thermal insulation properties is formed.

[0006] However, due to the significant gas convection effect, traditional micron-sized foamed or hollow particle coatings (pore size >1μm) generally have thermal conductivities exceeding 0.05 W / (m·K), making them difficult to meet the requirements for high-efficiency thermal insulation. While improving thermal insulation by thickening the coating or increasing the filler density can improve thermal insulation, this results in a loss of lightweight advantages. In theory, reducing the pore size to below the mean free path of gas molecules (100-200 nm at normal pressure) can exploit the Knudsen effect to inhibit gas heat conduction: when the pore-wall spacing is smaller than the mean free path of gas molecules, the frequency of molecular-wall collisions is higher than that of intermolecular collisions, and the gas thermal conductivity decreases by orders of magnitude (I&EC Fundamentals 1964, 3, 318). For example, the thermal conductivity of polyurethane foam containing nanopores can be reduced by 80% compared to micron-sized structures, approaching the performance of vacuum insulation panels. However, existing technologies make it difficult to achieve controllable preparation of nanopores and face two major challenges:

[0007] 1. The contradiction between nanopores and mechanical properties: Traditional foaming has difficulty in stably generating submicron pores, and nanopores are prone to collapse during the coating curing process. In existing technologies, nanoporous coatings (such as nanoaerogels) prepared by template or sol-gel methods can achieve low thermal conductivity (<0.02 W / (m·K)), but they are highly brittle (elongation at break <5%) and have poor adhesion (ASTM D3359 test ≤ Level 2), and cannot withstand dynamic mechanical loads such as textile bending and friction.

[0008] 2. Process bottlenecks in large-scale production: The stable control of nano-scale pores requires complex processes (such as supercritical drying and vacuum infusion), which have high equipment costs and long production cycles, making it difficult to meet the continuous processing needs of the textile industry.

[0009] Therefore, developing a textile coating technology that can be mass-produced and has both nanoscale pore structure and excellent mechanical properties has become a key direction to break through the performance bottleneck of existing thermal insulation materials. Summary of the Invention

[0010] The purpose of the present invention is to provide a lightweight thermal insulation textile coating based on hollow nanoparticles and a preparation and application method. Monodisperse hollow nanoparticles are used to construct a uniform pore system, and based on the Knudsen effect, the free path of gas molecules is controlled in the nanopores, thereby achieving both nanoscale pore structure and excellent mechanical properties.

[0011] To achieve the above objectives, the present technical solution provides a lightweight thermal insulation textile coating based on hollow nanoparticles, which is formed by surface-modified inorganic hollow nanoparticles uniformly dispersed in an aqueous polymer matrix, wherein the inorganic hollow nanoparticles have a closed-pore structure, and the inner diameter of the inorganic hollow nanoparticles is 40 to 200 nm, the wall thickness is 2 to 12 nm, and the porosity is ≥70%.

[0012] It should be noted that the inorganic hollow nanoparticles in the lightweight thermal insulation textile coating of this scheme have a closed-pore structure. The closed-pore structure can prevent the pores from being connected, thereby preventing gas convection between the pores. If the pores are connected, the gas will flow easily, and heat will also be transferred with the gas convection, resulting in a decrease in thermal insulation performance. The closed-pore structure of the hollow nanostructure of this scheme effectively prevents this from happening, making the thermal insulation effect of the coating more stable.

[0013] In some embodiments, the inner diameter of the inorganic hollow nanoparticles of this embodiment is 40 to 200 nm, preferably 40 to 100 nm. The mean free path of gas molecules at normal pressure is 100 to 200 nm, while the inner diameter of the inorganic hollow nanoparticles in this coating is 40 to 200 nm, which is smaller than the mean free path of gas molecules. When the pore-wall spacing is smaller than the mean free path of gas molecules, the Knudsen effect occurs, causing the frequency of collisions between gas molecules and the wall to be higher than that between molecules, and the thermal conductivity of the gas to decrease by orders of magnitude, greatly improving the thermal insulation efficiency of the coating, which is a key factor in achieving efficient thermal insulation.

[0014] In some embodiments, the inorganic hollow nanoparticles of this embodiment have a porosity of ≥70%, preferably ≥80%, and more preferably ≥90%. The 2-12 nm wall thickness and ≥70% porosity of these inorganic hollow nanoparticles combine to ensure structural stability while providing ample air-filled space. This appropriate wall thickness imparts strength to the particles, making them less susceptible to breakage during processing or use. The high porosity increases the air content within the coating, which, acting as a low-thermal-conductivity medium, further reduces the overall thermal conductivity of the coating and enhances its thermal insulation properties.

[0015] In some embodiments, the surface of the inorganic hollow nanoparticles is modified with a silane coupling agent or a titanate coupling agent, wherein the silane coupling agent or the titanate coupling agent is grafted with an organic functional group on the surface of the inorganic hollow nanoparticles. This modification can, on the one hand, improve the dispersion stability of the particles, so that they can be evenly dispersed in the aqueous polymer matrix, ensuring the consistency of the coating performance; on the other hand, it forms a chemical bond between the particles and the polymer matrix, thereby improving the interfacial bonding strength and enhancing the mechanical properties of the coating, such as adhesion to the substrate and the number of bending resistance. It can also improve the durability of the coating so that it can withstand long-term use and multiple washings.

[0016] Furthermore, the silane coupling compound is one of 3-aminopropyltrimethoxysilane and 3-(2,3-epoxypropyloxy)propyltrimethoxysilane.

[0017] When the silane coupling agent is 3-aminopropyltrimethoxysilane, amino groups are grafted onto the surface of the inorganic hollow nanoparticles. In its chemical structure, the aminopropyl moiety of 3-aminopropyltrimethoxysilane carries an amino group. During the surface modification process, the amino groups bind to the particle surface through a chemical reaction, thereby grafting the amino groups onto the surface of the inorganic hollow nanoparticles. This grafting process improves coating performance in several ways: it strengthens the interaction between the particles and the aqueous polymer matrix, creating a tighter bond; it improves the dispersion of the particles in the matrix, enhancing the uniformity and stability of the coating; and the amino groups can also participate in subsequent cross-linking reactions, further enhancing the mechanical properties and water resistance of the coating.

[0018] When the silane coupling agent is 3-(2,3-epoxypropyloxy)propyltrimethoxysilane, epoxy groups are grafted onto the surface of the inorganic hollow nanoparticles. During the modification process, the siloxane groups in the 3-(2,3-epoxypropyloxy)propyltrimethoxysilane molecule react chemically with hydroxyl groups and other groups on the surface of the inorganic hollow nanoparticles, achieving chemical bonding. This in turn grafts the epoxy-containing propoxy groups onto the particle surface. Due to the high reactivity of the epoxy groups, they can undergo cross-linking reactions with active groups (such as amino and carboxyl groups) in the waterborne polymer matrix under certain conditions, forming a denser network structure. This significantly improves the mechanical properties of the coating, such as its strength, hardness, and wear resistance, making it less susceptible to damage from external forces. Furthermore, the cross-linked structure formed by the epoxy groups effectively blocks erosion by external chemicals, improving the coating's tolerance to water and chemical reagents, thereby extending the coating's service life.

[0019] In some embodiments, the amount of the silane coupling agent or titanate coupling agent is 0.5%-5% of the mass of the inorganic hollow nanoparticles.

[0020] In some embodiments, the inorganic hollow nanoparticles are single oxides or composite oxides, wherein the single oxide is selected from one of silicon dioxide, titanium dioxide, aluminum oxide, and zirconium dioxide, preferably silicon dioxide, and the composite oxide is selected from one of soda-lime glass and borosilicate glass.

[0021] In some embodiments, the aqueous polymer matrix is ​​polyurethane, polyvinyl acetate, polystyrene, polyacrylate or copolymer emulsion thereof.

[0022] Polyurethane is a copolymer typically formed by the reaction of isocyanates with polyols. Commonly used isocyanate components include aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates, while commonly used polyols include polyether polyols and polyester polyols.

[0023] Polyvinyl acetate, polystyrene, polyacrylate or their copolymer emulsions are obtained by emulsion free radical polymerization of corresponding monomers. Polyacrylic resins include polymethyl acrylate, polyethyl acrylate, etc., and styrene resins include polystyrene, poly-α-methylstyrene, etc.

[0024] In some embodiments, the aqueous polymer matrix is ​​preferably a polymer emulsion having a glass transition temperature of -30°C to 50°C, ensuring the coating's flexibility (elongation at break > 150%) and low-temperature crack resistance.

[0025] In a second aspect, the present invention provides a method for preparing a lightweight thermal insulation textile coating based on hollow nanoparticles, comprising the following steps:

[0026] Step S1: adding inorganic hollow nanoparticles and a dispersant to deionized water and subjecting the mixture to ultrasonic or high-speed shear treatment using a homogenizer for 30 to 60 minutes to form a stable suspension; wherein the inorganic hollow nanoparticles have a closed-pore structure, an inner diameter of 40 to 200 nm, a wall thickness of 2 to 12 nm, and a porosity of ≥70%;

[0027] Step S2: mixing the suspension and the aqueous polymer emulsion to form a uniform coating liquid;

[0028] Step S3: applying the coating liquid to the surface of the textile substrate by knife coating, spraying or dipping.

[0029] In some embodiments, the inner diameter of the inorganic hollow nanoparticles of this embodiment is 40 to 200 nm, preferably, 40 to 100 nm.

[0030] In some embodiments, the inorganic hollow nanoparticles of this embodiment have a porosity of ≥70%, preferably, a porosity of ≥80%, and more preferably, a porosity of ≥90%.

[0031] In some embodiments, the surface of the inorganic hollow nanoparticles is modified using a silane coupling compound or a titanate coupling agent, wherein the silane coupling compound or the titanate coupling agent is grafted with an organic functional group on the surface of the inorganic hollow nanoparticles.

[0032] In some embodiments, the amount of the silane coupling agent or titanate coupling agent is 0.5%-5% of the mass of the inorganic hollow nanoparticles.

[0033] In some embodiments, the inorganic hollow nanoparticles are single oxides or composite oxides, wherein the single oxide is selected from one of silicon dioxide, titanium dioxide, aluminum oxide, and zirconium dioxide, preferably silicon dioxide, and the composite oxide is selected from one of soda-lime glass and borosilicate glass.

[0034] In some embodiments, the inorganic hollow nanoparticles are prepared using a template method.

[0035] Specifically, when the material of the inorganic hollow nanoparticles is silica, polystyrene nanoparticles are used as templates, first coated with silica, and then the polymer particles are removed to obtain inorganic hollow nanoparticles of silica; or, using emulsion droplets as templates, the silica precursor is hydrolyzed and condensed on the surface of the emulsion droplets to form inorganic hollow nanoparticles of silica; or, an amphiphilic silica polymer precursor is self-assembled in water and then hydrolyzed and condensed to obtain inorganic hollow nanoparticles of silica.

[0036] Specifically, when the material of the inorganic hollow nanoparticles is titanium dioxide, polystyrene nanoparticles are used as templates, first coated with titanium dioxide, and then the polymer particles are removed to obtain inorganic hollow nanoparticles of titanium dioxide.

[0037] In some embodiments, the dispersant in step S1 is a commercially available silicone or polyacrylate block copolymer.

[0038] In some embodiments, the aqueous polymer in the aqueous polymer emulsion in step S2 is one or a copolymer of two or more of polyurethane, polyvinyl acetate, polystyrene, and polyacrylate.

[0039] Furthermore, polyurethane is generally a copolymer obtained by the reaction of isocyanate and polyol. Commonly used isocyanates include aromatic diisocyanates, aliphatic diisocyanates and alicyclic diisocyanates, and commonly used polyols include polyether polyols, polyester polyols, etc.

[0040] Polyvinyl acetate, polystyrene, polyacrylate or copolymers thereof are obtained by emulsion free radical polymerization of corresponding monomers, wherein polyacrylate includes any one of polymethyl acrylate and polyethyl acrylate, and polystyrene includes any one of polystyrene and poly-α-methylstyrene.

[0041] In some embodiments, the aqueous polymer emulsion is preferably a polymer emulsion having a glass transition temperature of -30°C to 50°C, ensuring the coating's flexibility (elongation at break > 150%) and low-temperature crack resistance.

[0042] Furthermore, in step S2, the suspension and the aqueous polymer emulsion are mixed, and then a cross-linking agent and a thickener are added and stirred.

[0043] In some embodiments, the cross-linking agent in step S2 is selected from one of isocyanate, aziridine or polycarbodiimide compounds. In this case, the amount of the cross-linking agent is 1%-5% of the mass of the polymer matrix.

[0044] In some embodiments, the thickener in step S2 is selected from polyurethane, polyacrylate and other thickeners having a structure similar to that of the waterborne polymer.

[0045] It should be noted that in step S2, in order to mix the suspension and the aqueous polymer emulsion, a known stirring equipment is used, preferably, a planetary stirring and degassing device is selected, and in the mixing process, factors such as uniform mixing, degassing, and prevention of impurities are taken into consideration, and appropriate reaction conditions can be selected according to actual conditions; a foaming agent and a foam stabilizer (generally a surfactant such as sodium lauryl sulfate, sodium stearate, etc.) can also be added, and then foaming is performed to form a foam coating liquid.

[0046] In some embodiments, the mass ratio of the inorganic hollow nanoparticles in the coating solution is 5% to 20%, and the mass ratio of the aqueous polymer is 5% to 0%.

[0047] In some embodiments, the textile substrate in step S3 is a woven fabric, a knitted fabric or a non-woven fabric, and the fiber material of the textile substrate is selected from at least one of polyester, nylon, polyacrylonitrile, polypropylene, aramid, spandex, cotton, viscose, linen, silk, wool, carbon or glass.

[0048] In some embodiments, the coating liquid is applied to the surface of the textile substrate by knife coating, spraying or dipping, and then thermally cured at 80-120° C. to form a coating.

[0049] In some embodiments, the coating thickness on the textile substrate is 10-100 μm, and the coating amount of the inorganic hollow nanoparticles is 1-20 g / m².

[0050] The coating liquid can be applied to the textile substrate surface using known coating or coating equipment. Common coating equipment includes floating knife coaters, roller coaters, gravure coaters, die coaters, reverse roller coaters, metal strip coaters, and rotary screen coaters. The coating operation is performed by appropriately adjusting processing conditions such as the viscosity and gap of the compounding mixture. In addition to applying the foam coating liquid to the textile substrate surface using the aforementioned methods, rolling and pressing are also required to break up the foam and firmly adhere the coating to the substrate surface. Due to the excellent mechanical properties of inorganic hollow nanoparticles, the particles remain undamaged under the rolling pressure (45-294 N / cm) commonly used in textile coating.

[0051] In some embodiments, in step S1, inorganic hollow nanoparticles, a dispersant, and an additive are added together into deionized water, and subjected to ultrasound or high-speed shearing treatment by a homogenizer for 30 to 60 minutes to form a stable suspension, wherein the additive is a flame retardant or a UV absorber.

[0052] At this time, a flame retardant is added to make the lightweight thermal insulation textile coating based on hollow nanoparticles reach the UL94 V-0 flame retardant rating, wherein the flame retardant includes one or any combination of ammonium polyphosphate, triphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), melamine, and melamine cyanurate. The flame retardants can be used alone or in combination.

[0053] In some embodiments, the flame retardant is added in an amount of 10% to 30% by weight of the coating.

[0054] The addition of ultraviolet absorbers makes the ultraviolet protection factor UPF of the lightweight thermal insulation textile coating based on hollow nanoparticles ≥ 50, wherein the ultraviolet absorbers include one or any combination of benzotriazoles, benzophenones, triazines, nano-titanium dioxide, nano-zinc oxide, and composite metal oxides. The ultraviolet absorbers can be used alone or in combination.

[0055] Of course, in some embodiments, a UV absorber may be added in addition to the flame retardant.

[0056] Thirdly, this solution provides an application method for a lightweight thermal insulation textile coating based on hollow nanoparticles, which can be applied to outdoor clothing, smart home textiles, aerospace thermal protection, and building energy-saving curtains.

[0057] Compared with the existing technology, this technical solution has the following characteristics and beneficial effects:

[0058] Using inorganic hollow nanoparticles to create a closed-cell nanoporous coating with a pore diameter smaller than the mean free path of gas molecules, the coating significantly reduces thermal conductivity compared to traditional foam coatings and coatings containing micron-sized hollow particles. This allows for the desired thermal insulation effect to be achieved with a relatively low coating thickness. Furthermore, the coating exhibits excellent mechanical properties and a pleasant feel.

[0059] Specifically, this lightweight, thermally insulating textile coating based on hollow nanoparticles uses inorganic hollow nanoparticles as functional fillers. These are uniformly dispersed in a water-based polymer matrix through surface modification and dispersion processes, and then coated to form a nanoporous coating. These hollow nanoparticles possess a unique closed-pore nanostructure, significantly outperforming traditional micron-sized hollow particles in thermal conductivity. This improves insulation efficiency while also reducing the weight of the coating, offering the following advantages:

[0060] (1) Excellent thermal insulation performance, significantly improved over traditional foam coatings and micron-sized filler systems; (2) Lightweight properties, effectively reducing the overall weight of the textile; (3) Strong bonding with the substrate, excellent flexibility, and the ability to withstand repeated bending; (4) Outstanding durability. These advantages make this lightweight thermal insulation textile coating based on hollow nanoparticles suitable for long-term use and multiple washing needs. The present invention can be widely used in outdoor clothing, smart home textiles, and expanded to industrial fields such as aerospace thermal protection and building energy-saving curtains, providing innovative solutions for lightweight and efficient thermal insulation needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 The produced silica hollow nanoparticles have an average inner diameter of 100 nm, a wall thickness of 5 nm, and a porosity of 75%.

[0062] Figure 2 1 is a scanning electron microscope photograph of the coating surface obtained in Example 1.

[0063] Figure 3 This is a scanning electron microscope photo of Sphericel 45P25 hollow glass microspheres. DETAILED DESCRIPTION

[0064] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0065] The coating and testing methods in each embodiment are as follows:

[0066] The textile coating was carried out using a Labdryer LTE-S coating machine from Mathis AG, Switzerland.

[0067] The thermal conductivity of the textile coating was measured using the Kawabata evaluation system KES-F7 of Japan Kado Technology Co., Ltd. The test was carried out at a temperature of 22°C and a relative humidity of 55%.

[0068] The adhesion of the coating to the textile substrate is measured according to ASTM D3359; the flexural resistance of the coating is measured according to ISO 7854, and the washability is measured according to AATCC 135.

[0069] The ultraviolet protection factor (UPF) of coated textiles was measured using a UV-2000F textile ultraviolet protection factor tester in accordance with the national standard GB / T18830-2009.

[0070] Example 1

[0071] Go as Figure 1 1% of the amount of γ-aminopropyltrimethoxysilane was added to the aqueous dispersion of hollow silica nanoparticles shown in the figure, and the resulting suspension was stirred for a period of time and mixed with a commercial self-crosslinking waterborne polyacrylate emulsion (Edolan Chemical Co., Ltd.) ® A coating solution containing 15% hollow silica nanoparticles and 20% polyacrylate was prepared by mixing and stirring. The solution was applied to the polyester fabric using a knife coating method and heat-treated at 100°C for 10 minutes.

[0072] Figure 2 The SEM image of the coating surface is shown below. The average coating thickness is 54 microns and the coating weight is 39 g / m 2 .

[0073] in Figure 1 The silica hollow nanoparticles shown have an average inner diameter of 100 nm, a wall thickness of 5 nm, and a porosity of 75%.

[0074] Comparative Example 1a

[0075] The surface-modified Figure 1 The aqueous dispersion of hollow silica nanoparticles shown and the commercial self-crosslinking aqueous polyacrylate emulsion (Edolan ® A coating solution containing 15% hollow silica nanoparticles and 20% polyacrylate was prepared by mixing and stirring. The coating solution was applied to the polyester fabric using a knife coating method and heat-treated at 100°C for 10 minutes.

[0076] The average thickness of the coating was 55 μm and the coating weight was 39 g / m 2 .

[0077] in Figure 1 The silica hollow nanoparticles shown have an average inner diameter of 100 nm, a wall thickness of 5 nm, and a porosity of 75%.

[0078] Comparative Example 1b

[0079] will be as Figure 3 The hollow glass microspheres shown, a dispersant (BASF Dispex® Ultra PA4570) at 1% particle size, and γ-aminopropyltrimethoxysilane at 1% particle size were added to deionized water and ultrasonicated for 30 minutes to form a stable suspension. After stirring for a period of time, the suspension was mixed with a commercial self-crosslinking waterborne polyacrylate emulsion (Edolan ®Mix and stir the hollow glass microspheres (A and B) to create a coating solution containing 15% by weight of hollow glass microspheres and 20% by weight of polyacrylate. Apply the solution to the polyester fabric using a doctor blade and heat-treat at 100°C for 10 minutes.

[0080] The average thickness of the coating was 57 μm and the coating weight was 39 g / m 2 .

[0081] in Figure 3 The hollow glass microspheres shown are Sphericel 45P25 from Potters Industries Inc., with an average particle size of 14 μm and a density of 0.26 g / cm 3 .

[0082] Example 2

[0083] γ-aminopropyltrimethoxysilane (1% of the particle weight) was added to the aqueous dispersion of hollow silica nanoparticles (Ningbo Particle Technology Co., Ltd.). After stirring for a period of time, the resulting suspension was mixed with a commercially available aqueous polyurethane emulsion (Edolan ® SG) and cross-linking agent (Edolan ® The coating solution was prepared by mixing silica hollow nanoparticles (12% by weight), polyurethane (20% by weight), and crosslinking agent (1% by weight). The solution was applied to the nylon fabric surface using a doctor blade and heat-treated at 120°C for 10 minutes.

[0084] The average thickness of the coating was 52 μm and the coating weight was 40 g / m 2 .

[0085] in Figure 1 The silica hollow nanoparticles shown have an average inner diameter of 100 nm, a wall thickness of 5 nm, and a porosity of 75%.

[0086] Comparative Example 2

[0087] will be as Figure 3 The hollow glass microspheres shown in the figure, 1% of dispersant (BASF Dispex® Ultra PA4570) and 1% of γ-aminopropyltrimethoxysilane were added to deionized water and ultrasonicated for 30 minutes to form a stable suspension. The suspension was then mixed with a commercially available waterborne polyurethane emulsion (Edolan ® SG) and cross-linking agent (Edolan ® Mix and stir thoroughly to create a coating solution containing 12% hollow glass microspheres, 20% polyacrylate, and 1% crosslinker. Apply the solution to the nylon fabric using a doctor blade and heat-treat at 120°C for 10 minutes.

[0088] The average thickness of the coating was 54 μm and the coating weight was 39 g / m 2 .

[0089] in Figure 3 The hollow glass microspheres shown are Sphericel 45P25 from Potters Industries Inc., with an average particle size of 14 μm and a density of 0.26 g / cm 3 .

[0090] Example 3

[0091] Go as Figure 1 γ-aminopropyltrimethoxysilane (1% of the particle weight) was added to the aqueous dispersion of hollow silica nanoparticles (Ningbo New Granular Materials Co., Ltd.). After stirring for a period of time, the resulting suspension was mixed with a commercial self-crosslinking waterborne polyacrylate emulsion (Edolan Chemical Co., Ltd.). ® A foaming agent and foam stabilizer (sodium lauryl sulfate and sodium stearate) were added to the mixture, and the mixture was stirred with a frame stirrer to produce a foam coating solution. The weight ratio of hollow silica nanoparticles was 15%, the weight ratio of polyacrylate was 20%, and the weight ratio of foaming agent and foam stabilizer was 1%. The foam coating solution was applied to the surface of the polyester fabric using a knife coating method, and then pressed with a manual hydraulic embossing press at a linear pressure of 100 N / cm. The solution was then heat-treated at 100°C for 10 minutes.

[0092] The average coating thickness is 61μm and the coating amount is 41g / m 2 .

[0093] in Figure 1 The silica hollow nanoparticles shown have an average inner diameter of 100 nm, a wall thickness of 5 nm, and a porosity of 75%.

[0094] Comparative Example 3

[0095] will be as Figure 3 The hollow glass microspheres shown in the figure were mixed with 1% dispersant (BASF Dispex® Ultra PA4570) and 1% γ-aminopropyltrimethoxysilane in deionized water and treated with ultrasound for 30 minutes to form a stable suspension. After stirring for a period of time, the resulting suspension was mixed with a commercial self-crosslinking waterborne polyacrylate emulsion (Edolan ®A foaming agent and foam stabilizer (sodium lauryl sulfate and sodium stearate) were added to the mixture, and the mixture was stirred with a frame stirrer to produce a foam coating solution. The weight ratio of hollow silica nanoparticles was 15%, the weight ratio of polyacrylate was 20%, and the weight ratio of foaming agent and foam stabilizer was 1%. The foam coating solution was applied to the surface of the polyester fabric using a knife coating method, and then pressed with a manual hydraulic embossing press at a linear pressure of 100 N / cm. The solution was then heat-treated at 100°C for 10 minutes.

[0096] The average coating thickness is 59 μm and the coating weight is 39 g / m 2 .

[0097] in Figure 3 The hollow glass microspheres shown are Sphericel 45P25 from Potters Industries Inc., with an average particle size of 14 μm and a density of 0.26 g / cm 3 .

[0098] Example 4

[0099] γ-aminopropyltrimethoxysilane (1% of the particle weight) was added to the aqueous dispersion of hollow silica nanoparticles (Ningbo New Particle Materials Co., Ltd.). After stirring for a period of time, the resulting suspension was mixed with a commercial self-crosslinking waterborne polyacrylate emulsion (Edolan ® A coating solution was prepared by mixing silica hollow nanoparticles (15% by weight), polyacrylate (20% by weight), and a UV absorber (BASF Tinuvin 1130) and stirring them evenly to form a coating solution. The weight ratio of the hollow silica nanoparticles was 15%, the weight ratio of the polyacrylate was 20%, and the weight ratio of the UV absorber was 0.7%. The coating solution was applied to the surface of matte nylon cloth using a knife coating method and then heat-treated at 100°C for 10 minutes.

[0100] The average thickness of the coating was 54 μm and the coating weight was 39 g / m 2 . UV protection factor is 55.

[0101] in Figure 1 The silica hollow nanoparticles shown have an average inner diameter of 100 nm, a wall thickness of 5 nm, and a porosity of 75%.

[0102] The coating performance comparison chart of each embodiment and comparative example is shown in Table 1 below:

[0103] Table 1: Comparison of coating properties containing hollow silica nanoparticles and hollow glass microspheres.

[0104] .

[0105] As shown in Table 1, while the coating containing hollow nanoparticles has a slightly higher density than that containing hollow glass microspheres, its thermal conductivity is significantly lower (30-50%). This indicates that only half the thickness is required to achieve the same insulation effect as the hollow glass microsphere coating, thus achieving lightweighting. Furthermore, the mechanical strength of the former, such as adhesion to the substrate, bending resistance, and water washability, is significantly improved compared to the latter.

[0106] Those skilled in the art should understand that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The above embodiments merely illustrate several embodiments of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A lightweight thermal insulation textile coating based on hollow nanoparticles, characterized in that: The surface-modified inorganic hollow nanoparticles are uniformly dispersed in an aqueous polymer matrix, wherein the inorganic hollow nanoparticles have a closed-pore structure, an inner diameter of the inorganic hollow nanoparticles is 40 to 100 nm, a wall thickness of 2 to 5 nm, and a porosity of ≥70%.

2. The lightweight thermal insulation textile coating based on hollow nanoparticles according to claim 1, characterized in that The surface of the inorganic hollow nanoparticles is modified by using a silane coupling compound or a titanate coupling agent, wherein the silane coupling compound or the titanate coupling agent is grafted with an organic functional group on the surface of the inorganic hollow nanoparticles.

3. The lightweight thermal insulation textile coating based on hollow nanoparticles according to claim 2, characterized in that The amount of the silane coupling agent or titanate coupling agent is 0.5%-5% of the mass of the inorganic hollow nanoparticles.

4. The lightweight thermal insulation textile coating based on hollow nanoparticles according to claim 1, characterized in that The inorganic hollow nanoparticles are single oxides or composite oxides, wherein the single oxide is selected from one of silicon dioxide, titanium dioxide, aluminum oxide and zirconium dioxide.

5. The lightweight thermal insulation textile coating based on hollow nanoparticles according to claim 1, characterized in that The waterborne polymer matrix is ​​one or a copolymer of two or more of polyurethane, polyvinyl acetate, polystyrene and polyacrylate.

6. The lightweight thermal insulation textile coating based on hollow nanoparticles according to any one of claims 1 to 5, characterized in that It is used in outdoor clothing, smart home textiles, aerospace thermal protection, and building energy-saving curtains.

7. A method for preparing a lightweight thermal insulation textile coating based on hollow nanoparticles, characterized in that: The following steps are involved: Step S1: adding the inorganic hollow nanoparticles and the dispersant into deionized water, and subjecting the water to ultrasonic or high-speed shearing treatment using a homogenizer for 30 to 60 minutes to form a stable suspension; The inorganic hollow nanoparticles have a closed-pore structure, and the inner diameter of the inorganic hollow nanoparticles is 40 to 100 nm, the wall thickness is 2 to 5 nm, and the porosity is ≥70%; Step S2: mixing the suspension and the aqueous polymer emulsion to form a uniform coating liquid; Step S3: applying the coating liquid to the surface of the textile substrate by knife coating, spraying or dipping.

8. The method for preparing a lightweight thermal insulation textile coating based on hollow nanoparticles according to claim 7, characterized in that: The suspension and the aqueous polymer emulsion are mixed and then the cross-linking agent and the thickener are added and stirred.

9. The method for preparing a lightweight thermal insulation textile coating based on hollow nanoparticles according to claim 7, characterized in that: The textile substrate is a woven fabric, a knitted fabric or a non-woven fabric, and the fiber material of the textile substrate is selected from at least one of polyester, nylon, polyacrylonitrile, polypropylene, aramid, spandex, cotton, viscose, linen, silk, wool, carbon or glass.

10. The method for preparing a lightweight thermal insulation textile coating based on hollow nanoparticles according to claim 7, characterized in that: In step S1, inorganic hollow nanoparticles, a dispersant, and additives are added into deionized water.

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