A breathable metal composite textile and method of making the same

Abstract

The application provides a preparation method of a breathable metal composite textile, comprising the following steps: preparing a resin film with a microporous structure; performing activation treatment on one side of the resin film with the microporous structure to obtain an activated side of the resin film; depositing metal material on the activated side of the resin film by using a metal target to form a nanometer metal layer on the activated side; coating a composite slurry containing liquid metal, aqueous polyurethane dispersion and fluorine-containing polymer on the surface of the nanometer metal layer, and obtaining a composite heat reflection layer after heat treatment; and performing dot matrix composite of a fiber lining and the composite heat reflection layer of the resin film, so that the fiber lining and the resin film are combined only in a dot area, and a shaped product is obtained after shaping treatment, which is the breathable metal composite textile. Through the above structure combination, the nanometer metal layer realizes the heat reflection function while maintaining the connectivity of the microporous structure and the interlayer channel, so that the problem that the air permeability of the fabric is easily reduced when the metal layer is used for heat reflection is solved.

Description

Technical Field

[0001] This invention belongs to the field of composite fabric technology, and particularly relates to a breathable metal composite textile and its preparation method. Background Technology

[0002] Metallic textiles are composite materials that incorporate metallic elements or structures into traditional textile materials, giving them both the flexibility of textiles and the functional properties of metals. The metallic component can exist in the form of metal fibers, metal coatings, metal wire braids, vacuum-deposited metal layers, or liquid metal composite layers. Compared to ordinary fabrics, metallic textiles maintain softness, flexibility, and breathability while exhibiting electrical conductivity, thermal conductivity, electromagnetic shielding, antistatic properties, antibacterial properties, and thermal radiation regulation. The metallic layer, in particular, has a high reflectivity to infrared radiation, reflecting not only external heat radiation but also infrared heat radiated by the human body back to the skin, thus reducing heat loss and providing insulation and energy conservation. Therefore, metallic textiles have significant applications in thermal clothing and functional protective materials. The uses of metallic textiles are quite extensive. In the industrial field, it can be used for electromagnetic shielding covers, antistatic work clothes, and protective clothing for low-temperature environments; in the electronics field, it can be used for flexible circuits and conductive substrates for wearable devices; in the medical and health field, it can be used for physiotherapy fabrics and thermoregulatory materials; in outdoor and cold-weather applications, it can be used for clothing and equipment with heat-reflective insulation functions, which reduce heat loss by reflecting the infrared radiation of the human body, and improve the warmth retention effect while maintaining a lightweight structure.

[0003] However, traditional metal textiles typically employ continuous metal coatings, electroplating layers, or full-surface metal film structures to achieve stable electrical conductivity or heat reflectivity. While continuous metal layers can effectively reflect heat radiation, they also cover fabric pores, blocking the transmission paths of air and moisture, significantly reducing fabric breathability. To enhance adhesion, overall hot pressing or full-surface bonding is often required, which further compacts the fiber structure and blocks micropores. As a result, while achieving heat-reflective insulation, moisture inside the fabric is difficult to escape, leading to stuffiness and discomfort when worn, especially during exercise or in high-humidity environments. Therefore, how to achieve heat reflection and insulation while maintaining the breathability of the fabric is a crucial technical problem that needs to be solved in the field of metal composite textile materials. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a breathable metal composite textile and its preparation method, which aims to solve the problem that metal composite textiles are difficult to maintain breathability while achieving heat reflection function.

[0005] To solve the above-mentioned technical problems, the present invention is implemented as follows: The present invention proposes a method for preparing a breathable metal composite textile, the steps of which include: S1. Prepare a resin film with a microporous structure, and activate one side of the resin film to obtain the activated side of the resin film. S2. Deposit a metal material on the activated side of the resin film to form a nano-metal layer on the activated side; S3. A composite slurry containing liquid metal, waterborne polyurethane dispersion and fluoropolymer is coated onto the surface of the nano-metal layer, and a composite heat reflective layer is obtained after heat treatment. S4. The fiber lining and the composite heat-reflective layer of the resin film are composited in a dot matrix manner, so that the fiber lining and the composite heat-reflective layer form a local bond in the dot area. After shaping treatment, a breathable metal composite textile is obtained.

[0006] In some embodiments of the present invention, step S1 includes: S1.1 The thermoplastic matrix resin, micropore regulator and reinforcing agent are dried, and the thermoplastic matrix resin, micropore regulator and reinforcing agent are mixed at 300~800r / min according to the preset mass ratio to obtain a primary mixture; S1.2. Add the primary mixture to the screw extruder for melt mixing. Set the temperature of each zone of the extruder to 120~190℃, control the screw speed at 80~250 r / min, and maintain it in the vacuum exhaust section. 0.06~ A negative pressure of 0.09 MPa was applied to obtain a molten homogeneous mixture; S1.3. The molten homogeneous mixture is extruded into a film through a casting die, and the die temperature is controlled at 130~200℃ and the cooling roller temperature is 15~35℃ to obtain the resin film. During the cooling process, the resin film forms a microporous structure. S1.4. Activate one side of the resin film by using radio frequency plasma equipment to obtain the activated side of the resin film.

[0007] In some embodiments of the present invention, the thickness of the resin film is 10~80μm.

[0008] In some embodiments of the present invention, the thermoplastic matrix resin includes at least one of thermoplastic polyurethane, polyethylene, polypropylene, thermoplastic polyester elastomer, polyamide, and ethylene-vinyl acetate copolymer; the micropore regulator includes at least one of sodium bicarbonate, azodicarbonamide, and 4,4'-oxobisbenzenesulfonyl hydrazine; and the reinforcing agent includes at least one of nano-silica, nano-alumina, talc, transparent toughening resin, acrylic copolymer, polycarbonate microparticles, and styrene block copolymer.

[0009] In some embodiments of the present invention, the mass ratio of thermoplastic matrix resin: micropore regulator: reinforcing agent is (82~91):(6~12):(3~6).

[0010] In some embodiments of the present invention, step S2 includes: S2.1. Fix the resin film onto the substrate tray of the vacuum deposition equipment with the activated side facing upwards. Evacuate the cavity of the vacuum deposition equipment to a depth of 1×10⁻⁶. -3 ~1×10 -5 mbar; S2.2. Argon or a mixture of argon and oxygen is introduced into the vacuum deposition equipment, and the gas flow rate is controlled at 10~50 sccm, the working pressure is 0.2~1.0 Pa, and the radio frequency power is 20~150 W to perform in-situ ion cleaning treatment on the resin film. S2.3 The metal target material includes a metal seed material, a main metal, and a transition metal. The metal seed material is first deposited on the activated side surface of the resin film by magnetron sputtering with a sputtering power of 30~200W and a working pressure of 0.2~1.0Pa to obtain a metal seed material layer. S2.4. Deposit the main metal layer on the metal seed material layer by evaporation deposition, with a heating power of 50~400W, a working gas pressure of 0.2~1.5Pa, and a deposition rate of 0.05~1.0nm / s to obtain the main metal layer. S2.5. Deposit a transition metal layer on the surface of the main metal layer by magnetron sputtering. The working pressure is controlled within the range of 0.2~1.0Pa, the DC sputtering power is 50~250W, and the deposition rate is controlled within the range of 0.02~0.5nm / s to obtain the transition metal layer. S2.6 After the metal seed material layer, main metal layer and transition metal layer are deposited, they are combined to form a nano metal layer. The deposited resin film is subjected to low temperature shaping treatment and kept at 90-130℃ to obtain a resin film with a nano metal layer on the surface.

[0011] In some embodiments of the present invention, the thickness of the metal seed material layer is controlled to be 1~10nm, the thickness of the main metal layer is controlled to be 5~60nm, and the thickness of the transition metal layer is controlled to be within the range of 1~15nm.

[0012] In some embodiments of the present invention, in step S2, the metal seed material includes at least one of nickel, titanium, chromium, molybdenum, tantalum, and zirconium; the main metal includes at least one of aluminum, copper, silver, gold, zinc, and tin; and the transition metal includes at least one of nickel, titanium, chromium, stainless steel alloy, molybdenum, and tantalum.

[0013] In some embodiments of the present invention, step S3 includes: S3.1. Stir the aqueous polyurethane dispersion and the fluoropolymer at 300~800 r / min at room temperature to obtain a pre-dispersion. S3.2 Add liquid metal to the pre-dispersion liquid and disperse it under ultrasonic power of 200~800W to obtain slurry mother liquor; S3.3. Rheological regulation of the slurry mother liquor is carried out by stirring at 300~1000 r / min to control the viscosity of the slurry mother liquor within the range of 500~5000 mPa·s, so as to obtain a composite slurry. S3.4. Coat the surface of the nano-metal layer with the composite slurry to obtain the coating layer; S3.5. The coating layer is pre-dried at 90-130℃ and then hot-pressed at 0.2-0.8MPa to obtain the composite heat reflective layer.

[0014] In some embodiments of the present invention, the composite slurry is coated onto the surface of the nano-metal layer by screen printing, scraping or spraying, and the coating thickness is controlled to be 5~50μm.

[0015] In some embodiments of the present invention, in step S3, the liquid metal includes at least one of gallium-indium alloy, gallium-tin alloy, gallium-indium-tin alloy, pure gallium, and gallium-containing low-melting-point alloy; the aqueous polyurethane dispersion includes at least one of polyether-type aqueous polyurethane dispersion, polyester-type aqueous polyurethane dispersion, acrylic-modified aqueous polyurethane dispersion, and polycarbonate-type aqueous polyurethane dispersion; and the fluoropolymer includes at least one of fluorinated acrylic resin, fluorinated polyurethane, and fluorinated acrylic copolymer.

[0016] In some embodiments of the present invention, the mass ratio of aqueous polyurethane dispersion: liquid metal: fluoropolymer is (60~75):(20~35):(3~8).

[0017] In some embodiments of the present invention, step S4 includes: S4.1. A composite heat-reflective layer with a mask having a lattice hole structure is covered with a resin film. A selective solvent is applied to the exposed lattice hole area by spraying or roller coating to soften it. The selective solvent is used to soften the waterborne polyurethane continuous phase in the composite heat-reflective layer, so that the fiber lining is locally bonded to the composite heat-reflective layer in the lattice hole area. S4.2 Dry the fiber lining at 50~80℃, and then bond the fiber lining to the resin film under normal pressure so that the fiber lining forms a local bond with the composite heat reflective layer in the dot matrix area, while no bond is formed in the areas that are not in contact with the solvent. S4.3 After lamination, the composite structure is placed at 60-90℃ for shaping treatment to obtain breathable metal composite textile.

[0018] In some embodiments of the present invention, in step S4, the selective solvent includes at least one of ethyl acetate, acetone, and methyl ethyl ketone, and the amount of selective solvent is controlled to be 0.5~10 g / m³. 2 .

[0019] This invention proposes a breathable metal composite textile, which is manufactured by the method described above for preparing a breathable metal composite textile.

[0020] Compared with the prior art, the breathable metal composite textile and its preparation method of this invention have the following advantages: This technical solution involves preparing a resin film with a microporous structure in step S1, creating continuous gas channels within the material to structurally ensure that air and water vapor can pass through the film. In step S2, a nano-metal layer is deposited on the activated side. Utilizing the reflective properties of metal materials, the nano-metal layer reflects external infrared thermal radiation, thereby reducing heat transfer into the fabric. Because this metal layer is nanoscale thick and constructed on the surface of the microporous film, it provides heat reflection without forming a thick, dense coating, minimizing its impact on the breathable structure. In step S3, a composite heat-reflective layer is formed by combining liquid metal, waterborne polyurethane dispersion, and fluoropolymer. This enhances the heat reflection function based on the nano-metal layer without relying on increasing the metal layer thickness, thus avoiding further pore blockage due to enhanced heat reflection. Finally, in step S4, a dot-matrix composite process is used to locally bond the fiber lining with the composite heat-reflective layer only in dotted areas. This local bonding connects the fiber lining to the resin film, while the unbonded areas remain open, ensuring that the overall structure retains air and moisture transport channels between layers. Through this structural combination, the heat-reflective function of the nano-metal layer is achieved while maintaining the connectivity of the microporous structure and interlayer channels, thus solving the problem that metal layers used for heat reflection easily reduce the breathability of fabrics. Attached Figure Description

[0021] Figure 1 This is a schematic flowchart of a method for preparing a breathable metal composite textile according to an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] Please refer to Figure 1 A method for preparing a breathable metal composite textile, comprising the following steps: S1. A resin film with a microporous structure is provided, and one side of the resin film is activated to obtain an activated side of the resin film. In some embodiments, the resin film with a microporous structure can be a pre-prepared microporous resin film, or it can be formed by melt mixing to form a film, foaming to form pores, phase separation to form pores, stretching to form pores, filler extraction to form pores, or a combination thereof. Preferably, the resin film with a microporous structure is formed by melt mixing a thermoplastic matrix resin, a microporous regulator, and a reinforcing agent in a preset mass ratio. The thermoplastic matrix resin includes at least one of thermoplastic polyurethane, polyethylene, polypropylene, thermoplastic polyester elastomer, polyamide, and ethylene-vinyl acetate copolymer; the microporous regulator includes at least one of sodium bicarbonate, azodicarbonamide, and 4,4'-oxobisbenzenesulfonyl hydrazine; and the reinforcing agent includes at least one of nano-silica, nano-alumina, talc, transparent toughening resin, acrylic copolymer, polycarbonate microparticles, and styrene block copolymer. Preferably, the mass ratio of thermoplastic matrix resin: micropore regulator: reinforcing agent is (82~91):(6~12):(3~6).

[0024] S1.1. Dry the thermoplastic matrix resin at 70~90℃ for 4~8h, and dry the micropore regulator and reinforcing agent at 50~80℃ for 2~6h. Mix the thermoplastic matrix resin, micropore regulator and reinforcing agent at 300~800r / min for 3~10min according to the preset mass ratio to obtain a primary mixture.

[0025] Drying the thermoplastic matrix resin at 70–90℃ for 4–8 hours effectively removes adsorbed moisture and residual volatiles, preventing bubbles or localized structural defects caused by moisture vaporization during subsequent melting. Drying the micropore regulator and reinforcing agent at 50–80℃ for 2–6 hours helps reduce powder agglomeration and moisture content fluctuations, improving their dispersion uniformity in the resin. Mixing at 300–800 rpm for 3–10 minutes ensures that micropore regulators such as sodium bicarbonate and 4,4'-oxobisbenzenesulfonyl hydrazine are evenly distributed among the thermoplastic polyurethane, polyethylene, or polyamide matrix resin particles, while simultaneously allowing reinforcing agents such as nano-silica and talc to form a stable pre-dispersion state.

[0026] S1.2. Add the primary mixture to a twin-screw extruder for melt mixing. Set the temperature of each zone of the extruder to 120~190℃, control the screw speed at 80~250 r / min, and allow the primary mixture to remain in the barrel for 1~5 minutes, maintaining this temperature in the vacuum exhaust section. 0.06~ A negative pressure of 0.09 MPa was applied to obtain a molten homogeneous mixture.

[0027] Melt mixing at 120–190℃ allows thermoplastic polyurethane, polyethylene, or thermoplastic polyester elastomers to fully melt and form a continuous phase, enabling micropore regulators to form dispersed phases or pore-forming induction sites within the melt. Controlling the screw speed at 80–250 r / min and the residence time at 1–5 min enhances shear dispersion, ensuring uniform distribution of sodium bicarbonate, azodicarbonamide, or low-boiling-point organic solvents within the melt. Maintaining a vacuum exhaust section... 0.06~ A negative pressure of 0.09 MPa helps to expel excess volatiles and prevents gas from accumulating prematurely and forming irregular large pores.

[0028] S1.3. The molten homogeneous mixture is extruded through a casting die to form a film. The die temperature is controlled at 130~200℃ and the cooling roller temperature is controlled at 15~35℃ to obtain a resin film with a thickness of 10~80μm. During the cooling process, the resin film forms a microporous structure.

[0029] A resin film with a thickness of 10–80 μm is obtained by casting at a die temperature of 130–200℃ and a cooling roller temperature of 15–35℃. During the controlled cooling process, thermally induced phase separation or volatilization-induced pore behavior occurs, resulting in a uniformly distributed microporous structure inside the resin film.

[0030] S1.4. Activate one side of the resin film by using a radio frequency plasma device at a power of 20~200W and an oxygen or argon atmosphere for 10~60s to obtain the activated side of the resin film.

[0031] By using radio frequency plasma equipment at a power of 20–200W in an oxygen or argon atmosphere for 10–60s, polar groups can be introduced onto the film surface, increasing surface energy and enhancing nucleation ability and adhesion during metal deposition.

[0032] S2. The resin film is placed in a vacuum deposition apparatus, and a metal material is deposited on the activated side using a metal target to form a nano-metal layer on the activated side. In some embodiments, the nano-metal layer can be a single-layer metal layer or a multi-layer metal composite layer. Preferably, the nano-metal layer includes a metal seed material layer, a main metal layer, and a transition metal layer formed sequentially.

[0033] Step S2 includes: S2.1. Fix the resin film onto the substrate tray of the vacuum deposition equipment with the activated side facing upwards. Evacuate the cavity of the vacuum deposition equipment to a depth of 1×10⁻⁶. -3 ~1×10 -5 mbar.

[0034] Fix the resin film to the substrate tray with the activated side facing up, and then pull the cavity to 1×10.-3 ~1×10 -5 A vacuum environment (mbar) can significantly reduce the content of residual oxygen, water vapor, and volatile organic compounds within the deposition chamber. The low-pressure environment helps increase the mean free path of metal atoms during deposition, allowing them to reach the film surface more uniformly, thus forming a continuous and dense nanomaterial layer. Simultaneously, the vacuum environment reduces the likelihood of metal oxidation in the early stages of deposition, improving the purity and interfacial bonding quality of seed materials such as nickel, titanium, and chromium.

[0035] S2.2. Argon or a mixture of argon and oxygen is introduced into the vacuum deposition equipment. The gas flow rate is controlled at 10~50 sccm, the working pressure is 0.2~1.0 Pa, and the radio frequency power is 20~150 W. The resin film is then subjected to in-situ ion cleaning for 10~90 s.

[0036] In-situ ion cleaning for 10–90 seconds under working pressures of 0.2–1.0 Pa and RF power of 20–150 W can effectively remove any residual organic contaminants and weakly bonded layers on the activated side surface. Argon plasma primarily acts as a physical bombardment agent, effectively cleaning the surface; the argon-oxygen mixture can introduce appropriate polar groups onto the surface, further increasing surface energy. After ion cleaning, the resin film surface is more prone to forming high-density metal nucleation sites, allowing for more uniform adhesion of subsequent nickel, titanium, chromium, and other metal seed materials.

[0037] S2.3 The metal materials used to form the nano-metal layer include metal seed materials, main metal materials, and transition metal materials. The metal seed materials are first deposited on the activated side surface of the resin film by magnetron sputtering. The sputtering power is 30~200W, the working pressure is 0.2~1.0Pa, and the deposition time is 5~60s to obtain the metal seed material layer. The thickness of the metal seed material layer is controlled to be 1~10nm. The metal seed materials include at least one of nickel, titanium, chromium, molybdenum, tantalum, and zirconium.

[0038] A 1–10 nm thick metal seed material layer is deposited via magnetron sputtering to form a uniformly distributed nucleation base layer of metals such as nickel, titanium, chromium, molybdenum, tantalum, or zirconium on the activated side surface. These metals possess good interfacial adhesion and chemical stability, enabling them to form stable interfaces with the plasma-activated polymer surface. The relatively thin metal seed material layer facilitates the formation of continuous nucleation sites without significantly affecting the film's flexibility.

[0039] S2.4. Deposit a main metal layer on the metal seed material layer by evaporation deposition, with a heating power of 50~400W, a working gas pressure of 0.2~1.5Pa, and a deposition rate of 0.05~1.0nm / s to obtain the main metal layer. The thickness of the main metal layer is controlled at 5~60nm. The main metal includes at least one of aluminum, copper, silver, gold, zinc, and tin.

[0040] A 5–60 nm thick host metal layer is deposited on a metal seed material layer to form a continuous or semi-continuous thermal reflective framework structure of aluminum, copper, silver, gold, zinc, or tin. Aluminum exhibits good reflectivity and low density, copper and silver have high thermal reflectivity, while gold and tin have good stability. By controlling the deposition rate (0.05–1.0 nm / s) and gas pressure conditions, the surface migration behavior of metal atoms can be tuned to form a relatively uniform nanolayer structure.

[0041] S2.5. Deposit a transition metal layer on the surface of the main metal layer by magnetron sputtering. The working gas pressure is controlled within the range of 0.2~1.0 Pa, the DC sputtering power is 50~250 W, the deposition rate is controlled within 0.02~0.5 nm / s, and the deposition time is controlled within 10~120 s to obtain the transition metal layer. The thickness of the transition metal layer is controlled within the range of 1~15 nm. The transition metal includes at least one of nickel, titanium, chromium, stainless steel alloy, molybdenum, and tantalum.

[0042] Depositing a 1-15 nm thick transition metal layer on the surface of the main metal layer can form a protective and interface-stabilizing layer. Nickel, titanium, chromium, stainless steel alloys, molybdenum, or tantalum have good corrosion resistance and oxidation resistance, which can effectively slow down the oxidation of the main metal layer in air, sweat, or humid and hot environments. By controlling the deposition rate to 0.02-0.5 nm / s and an appropriate power, the transition layer can be uniformly covered without becoming too thick, thus avoiding a significant increase in resistance.

[0043] S2.6 After the deposition of the metal seed material layer, the main metal layer and the transition metal layer are completed, they are combined to form a nano metal layer. The deposited resin film is subjected to low-temperature shaping treatment and kept at 90-130℃ for 10-60 min to obtain a resin film with a nano metal layer on the surface.

[0044] Low-temperature setting at 90–130℃ for 10–60 minutes can release the internal stress generated during deposition, resulting in a more stable interlayer bonding structure between the metal seed material layer, the main metal layer, and the transition metal layer. This low-temperature treatment avoids damage to the microporous structure and also improves the crack resistance of the metal layer during bending or washing.

[0045] S3. Liquid metal, aqueous polyurethane dispersion, and fluoropolymer are mixed and dispersed in a preset ratio to prepare a composite slurry. The composite slurry is coated on the surface of the nano-metal layer and heat-treated to obtain a composite heat-reflective layer. The liquid metal includes at least one of gallium-indium alloy, gallium-tin alloy, gallium-indium-tin alloy, pure gallium, and gallium-containing low-melting-point alloy. The aqueous polyurethane dispersion includes at least one of polyether-type aqueous polyurethane dispersion, polyester-type aqueous polyurethane dispersion, acrylic-modified aqueous polyurethane dispersion, and polycarbonate-type aqueous polyurethane dispersion. The fluoropolymer includes at least one of fluorinated acrylic resin, fluorinated polyurethane, and fluorinated acrylic copolymer. The mass ratio of aqueous polyurethane dispersion: liquid metal: fluoropolymer is (60~75):(20~35):(3~8).

[0046] In some embodiments, the composite heat-reflective layer can be formed by coating a composite slurry in one step, or by coating two or more composite slurries in layers. The relative contents of liquid metal, aqueous polyurethane dispersion, and fluoropolymer in different coatings can be the same or different to form a liquid metal enriched layer, a fluoropolymer enriched layer, a porous protective layer, or a combination thereof.

[0047] First, liquid metals themselves possess high free electron density and excellent infrared reflectivity. Low-melting-point liquid metals such as gallium-indium alloys and gallium-tin alloys can form continuous or quasi-continuous metal microstructure networks on the substrate surface after coating. These metals have a strong reflective effect in the infrared band, reflecting infrared heat radiated outward from the human body back to the body surface, thereby reducing heat loss. Due to the fluidity of liquid metals, they can spread on the surface of the nano-metal layer and form good interfacial contact during heat treatment, which helps to improve the continuity and uniformity of the reflective layer, thereby improving the overall reflectivity. Second, the aqueous polyurethane dispersion plays a role in structural fixation and interface regulation in the system. After the aqueous polyurethane film is formed, it forms a continuous elastic matrix that stably encapsulates and fixes the liquid metal particles or microstructures, preventing them from migrating or falling off during bending, and ensuring that the reflective layer maintains structural integrity after multiple deformations. The presence of the polyurethane matrix can also optimize the distribution of liquid metal on the surface, making the metal phase form a more uniform reflective interface on a macroscopic scale, thereby improving the reflectivity stability of infrared radiation. Furthermore, fluoropolymers possess low surface energy and strong infrared reflection and scattering properties. On one hand, they reduce surface thermal emissivity, minimizing heat emission; on the other hand, they generate a certain degree of infrared scattering effect through microphase interface differences, causing incident or radiated infrared waves to be reflected multiple times at the interface, thereby improving overall reflection efficiency. Fluorine-containing components can also improve surface weather resistance and water resistance, ensuring stable reflectivity in humid environments.

[0048] Step S3 includes: S3.1. Stir the aqueous polyurethane dispersion and the fluoropolymer at 300~800 r / min for 10~30 min at room temperature to obtain a pre-dispersion.

[0049] Stirring at 300–800 rpm for 10–30 min at room temperature ensures thorough mixing of the aqueous polyurethane dispersion and the fluoropolymer, facilitating the formation of a stable continuous polymer phase. The aqueous polyurethane dispersion exhibits good film-forming properties and flexibility, making it suitable as a structural matrix for composite heat-reflective layers. The fluoropolymer possesses low surface energy and strong hydrophobicity, enabling it to form a dispersed phase or interfacial enrichment structure within the system. Thorough stirring ensures uniform distribution of the fluoropolymer within the aqueous polyurethane dispersion, providing conditions for subsequent interfacial interactions with the liquid metal oxide layer.

[0050] S3.2 Add liquid metal to the pre-dispersion liquid and disperse it under ultrasonic power of 200~800W for 10~40min to obtain slurry mother liquor.

[0051] Adding liquid metals such as gallium-indium alloy, gallium-tin alloy, or pure gallium to a pre-dispersion solution and dispersing it under ultrasonic power of 200–800 W for 10–40 min can disperse the liquid metal into micron- or submicron-sized droplet structures. During dispersion, the liquid metal forms a surface oxide layer, which can interact with the polar groups in waterborne polyurethane and simultaneously form a stable interface structure with fluoropolymers. The uniformly dispersed liquid metal microdroplets can then serve as reconfigurable heat-reflective units in subsequent film formation, improving the continuity of the overall heat-reflective network.

[0052] S3.3 Rheological regulation of the slurry mother liquor is carried out by stirring at 300~1000 r / min for 5~20 min to control the viscosity of the slurry mother liquor within the range of 500~5000 mPa·s, thereby obtaining a composite slurry.

[0053] The slurry mother liquor was stirred at 300–1000 r / min for 5–20 min to achieve rheological regulation, maintaining a viscosity within the range of 500–5000 mPa·s. This ensures the slurry possesses both good flowability and appropriate coating stability. Waterborne polyurethane provides a continuous phase structure with uniformly distributed liquid metal droplets, while the fluoropolymer forms a barrier at the interface. Viscosity control prevents sedimentation or aggregation of the liquid metal during coating, while also reducing sagging and localized buildup.

[0054] S3.4. The composite paste is coated onto the surface of the nano-metal layer by screen printing, scraping or spraying, and the coating thickness is controlled to be 5~50μm to obtain the coating layer.

[0055] By coating the surface of the nano-metal layer with a composite slurry at a thickness of 5–50 μm, a flexible composite layer can be constructed on top of the existing nano-metal framework. Screen printing, blade coating, or spraying methods can be used to form continuous or patterned structures as needed. The nano-metal layer provides basic heat reflection, with liquid metal droplets forming bridging structures within it, which are then encapsulated and fixed by a waterborne polyurethane film. Fluoropolymer enrichment at the interface enhances the surface's water resistance and corrosion resistance.

[0056] S3.5. Pre-dry the coating layer at 90-130℃ for 5-30 minutes, then pressurize it to 0.2-0.8MPa for 10-120 seconds to obtain the composite heat reflective layer.

[0057] Pre-drying at 90–130°C for 5–30 min removes moisture from the aqueous system, allowing the waterborne polyurethane to gradually form a film and fix the liquid metal microdroplet structure. Subsequently, hot pressing at 0.2–0.8 MPa for 10–120 s helps to enhance the contact between the liquid metal microdroplets and the nano-metal layer, improve the stability of the interfacial electrical connection, and promote the rearrangement of polymer chain segments.

[0058] S4. The fiber lining and the composite heat-reflective layer of the resin film are laminated in a dot matrix pattern, so that the fiber lining and the composite heat-reflective layer are locally bonded in the dotted areas. After shaping treatment, a breathable metal composite textile is obtained. In some embodiments, the dotted areas can be circular, elliptical, polygonal, or irregular dotted areas, and multiple dotted areas can be distributed in a matrix, staggered array, honeycomb array, or random array. By making the fiber lining locally bonded to the composite heat-reflective layer only in the dotted areas, air and moisture transmission channels can be maintained between adjacent dotted areas.

[0059] Step S4 includes: S4.1. A mask with a lattice-hole structure is placed over a resin film composite heat-reflective layer. A selective solvent is applied to the exposed lattice-hole areas by spraying or roller coating to soften the layer. The selective solvent is used to soften the waterborne polyurethane continuous phase in the composite heat-reflective layer, causing the fiber lining to locally bond with the composite heat-reflective layer in the lattice-hole areas. The softening time is controlled to be 5-60 seconds. The selective solvent includes at least one of ethyl acetate, acetone, and methyl ethyl ketone, and the amount of selective solvent is controlled to be 0.5-10 g / m³. 2 .

[0060] By covering the surface with a mask plate featuring a lattice-pore structure, selective solvents can act only on the exposed lattice-pore areas, achieving spatially selective softening of localized areas of the composite heat-reflective layer and locally softening of the adjacent resin film surface. Solvents such as ethyl acetate, acetone, methyl ethyl ketone, tetrahydrofuran, or similar solvents can induce surface swelling or softening of the thermoplastic polyurethane, polyethylene, or polyamide matrix within a short time, enhancing the mobility of polymer segments within the dotted regions. Controlling the solvent dosage within the range of 0.5–10 g / m² avoids excessive solvent penetration into the micropores or affecting the nanostructure of the metal layer. Controlling the softening time to 5–60 seconds facilitates the formation of bondable windows while minimizing impact on the overall mechanical structure. The technical advantage of this step lies in achieving a bondable state of the lattice regions through localized swelling of the material itself, rather than relying on overall pressure, thereby forming regular dotted bonding regions without disrupting the continuity of the micropores.

[0061] S4.2. Dry the fiber lining at 50~80℃ for 10~60min. Then, bond the fiber lining to the composite heat-reflective layer of the resin film under normal pressure, so that the fiber lining forms a local bond with the composite heat-reflective layer in the lattice hole area, and no bond is formed in the area that is not in contact with the solvent.

[0062] Drying the fiber lining at 50-80℃ for 10-60 minutes removes moisture from the fibers, improving their dimensional stability and bonding consistency. Bonding under normal pressure allows the fiber lining to embed into the solvent-softened lattice areas, forming localized bonds, while areas not in contact with the solvent retain their original hardness and do not adhere. This bonding method avoids the compression or deformation of the composite heat-reflective layer caused by overall hot pressing, and helps maintain a stable contact structure between the liquid metal and the nano-metal layer. The technical advantage of this step is the formation of a regular lattice bond structure, ensuring both peel strength and breathable channels in the unbonded areas, thus balancing structural strength with air and moisture transport capabilities.

[0063] S4.3 After lamination, the composite structure is placed at 60-90℃ for 10-60 minutes for shaping treatment to obtain breathable metal composite textile.

[0064] A setting process at 60–90℃ for 10–60 minutes facilitates the evaporation of residual solvents and the re-stabilization of polymer chain segments, thus fixing the interfacial structure of the lattice bonding regions. This setting process releases internal stress generated during bonding, reducing the risk of delamination during subsequent bending or washing. Because the setting temperature is lower than the overall melting temperature of the resin, it does not cause microporous structure collapse or significantly alter the morphology of the composite heat-reflective layer. The technical advantage of this step is that it stabilizes the lattice bonding morphology, improves interlayer bonding durability, and maintains the overall material's breathability and heat-reflective stability.

[0065] This invention proposes a breathable metal composite textile, which is made by the above-described method for preparing a breathable metal composite textile.

[0066] In some embodiments, the breathable metal composite textile includes a resin film with a microporous structure, a nano-metal layer formed on one side of the resin film, a composite heat-reflective layer formed on the surface of the nano-metal layer, and a fiber lining dot-matrix bonded to the composite heat-reflective layer. The fiber lining forms a partial bond with the composite heat-reflective layer in the dot-matrix areas, while the non-bonded areas form air and moisture transport channels between the fiber lining and the composite heat-reflective layer.

[0067] In several feasible embodiments, the breathable metal composite textile comprises at least four layers: a first layer is a fiber lining, a second layer is a resin film, a third layer is a nano-metal layer, and a fourth layer is a protective layer, which may be a voile or a voile fabric.

[0068] Example 1: Weigh out 820g of thermoplastic polyurethane, 100g of sodium bicarbonate, and 50g of nano-silica (thermoplastic matrix resin: micropore conditioner: reinforcing agent = 82:10:5), where sodium bicarbonate is used as the micropore conditioner and nano-silica as the reinforcing agent. Dry the thermoplastic polyurethane at 80℃ for 6 hours, and dry the sodium bicarbonate and nano-silica at 60℃ for 4 hours. Add the above amounts to a high-speed mixer and mix at 600 rpm for 6 minutes to obtain a primary mixture. Add the primary mixture to a twin-screw extruder for melt mixing, setting the temperatures of each zone to 150℃, 165℃, 175℃, and 185℃ sequentially, with a screw speed of 180 rpm and a material residence time of 3 minutes, maintaining this temperature in the vacuum exhaust section. A molten homogeneous mixture was obtained under a negative pressure of 0.08 MPa; subsequently, it was extruded into a film through a casting die at a die temperature of 180°C and a cooling roller temperature of 25°C, resulting in a resin film with a thickness of 30 μm. During the cooling process, a microporous structure was formed. One side of the film was activated by radio frequency plasma treatment at 120 W power in an oxygen atmosphere for 30 s, yielding the activated side of the resin film.

[0069] The resin film is fixed onto the substrate tray of the vacuum deposition equipment with the activated side facing upwards, and a vacuum of 1×10⁻⁶ is applied. - 4mbar; Argon gas was introduced at a flow rate of 30 sccm, working pressure of 0.6 Pa, and RF power of 80 W for in-situ ion cleaning for 40 s. A metal seed material layer of approximately 5 nm thickness was deposited using magnetron sputtering at a sputtering power of 100 W, working pressure of 0.6 Pa, and a deposition time of 20 s. A main metal layer of approximately 30 nm thickness was then deposited on the seed material layer using evaporation deposition at a heating power of 200 W, working pressure of 0.8 Pa, and deposition rate of 0.2 nm / s for 150 s. A transition metal layer of approximately 5 nm thickness was then deposited on the surface of the main metal layer using magnetron sputtering at a DC sputtering power of 120 W, working pressure of 0.6 Pa, and deposition rate of 0.1 nm / s for 50 s. After deposition, the film was cryogenically set at 60 °C for 30 min to obtain a resin film with a nano-metal layer on its surface.

[0070] A composite system was prepared according to the ratio of waterborne polyurethane dispersion: liquid metal: fluoropolymer = 65:30:5. 65g of polyether-type waterborne polyurethane dispersion, 30g of gallium-indium alloy, and 5g of fluorinated acrylic resin were weighed. First, the polyether-type waterborne polyurethane dispersion and fluorinated acrylic resin were stirred at 500 rpm for 20 min at room temperature to obtain a pre-dispersion. Gallium-indium alloy was added to the pre-dispersion, and the mixture was dispersed under ultrasonic power of 400 W for 20 min to obtain a slurry mother liquor. Rheological regulation was performed by stirring at 600 rpm for 10 min to control the viscosity at 2000 mPa·s to obtain a composite slurry. The composite slurry was coated onto the surface of the nano-metal layer using a blade coating method, controlling the coating thickness to 20 μm to obtain a coating layer. After pre-drying at 110℃ for 15 min, it was then hot-pressed at 0.5 MPa for 30 s to obtain a composite heat-reflective layer.

[0071] A composite heat-reflective layer, consisting of a mask with a lattice-pore structure, is overlaid on a resin film. Ethyl acetate is then applied to the exposed lattice-pore areas via roller coating to soften the lattice-pores. The solvent dosage is 3 g / m². 2 The softening time is 20 seconds. After drying the fiber lining at 70°C for 30 minutes, it is bonded to the composite heat-reflective layer of the resin film under normal pressure, so that the fiber lining only forms local adhesion to the composite heat-reflective layer in the dot matrix area. After bonding, the composite structure is placed at 60°C for 30 minutes to set, and a breathable metal composite textile is obtained.

[0072] Example 2: 860g of thermoplastic polyurethane, 90g of azodicarbonamide, and 50g of nano-silica were used as raw materials, with a mass ratio of thermoplastic matrix resin:micropore regulator:reinforcing agent of 86:9:5. First, the thermoplastic polyurethane was dried at 80℃ for 6 hours, and the azodicarbonamide and nano-silica were dried at 60℃ for 4 hours. Then, the mixture was added to a high-speed mixer according to the above ratio and stirred at 600 rpm for 7 minutes to obtain a primary mixture. The primary mixture was then added to a twin-screw extruder for melt mixing. The extruder temperature zones were set to 150℃, 165℃, 175℃, and 185℃, the screw speed was 180 rpm, and the material remained in the barrel for approximately 3 minutes, maintained in the vacuum exhaust section. A molten homogeneous mixture was obtained under a negative pressure of 0.08 MPa. This mixture was then extruded through a casting die at 180°C and a cooling roller at 25°C to produce a resin film approximately 30 μm thick, which formed a microporous structure during cooling. One surface of the resin film was treated with radio frequency plasma at 120 W power in an oxygen atmosphere for 30 seconds to obtain the activated side of the resin film.

[0073] The resin film is fixed on the substrate tray of the vacuum deposition equipment with the activated side facing upwards, and the deposition chamber is evacuated to 5 × 10⁻⁶. -4 mbar. Argon gas was introduced into the chamber at a flow rate of 30 sccm, a working pressure of 0.6 Pa, and a radio frequency power of 80 W to perform in-situ ion cleaning of the resin film for 40 s. Subsequently, a metal seed material layer was deposited by magnetron sputtering. Titanium was selected as the metal seed material, with a sputtering power of 100 W, a working pressure of 0.6 Pa, and a deposition time of 20 s, resulting in a metal seed material layer with a thickness of approximately 5 nm. On the metal seed material layer, a main metal layer was deposited by evaporation deposition. Aluminum was selected as the main metal, with a heating power of 200 W, a working pressure of 0.8 Pa, and a deposition rate of 0.2 nm / s, for 150 s, resulting in a main metal layer with a thickness of approximately 30 nm. Subsequently, a transition metal layer was deposited on the surface of the main metal layer by magnetron sputtering. Nickel was selected as the transition metal, with a DC sputtering power of 120 W, a working pressure of 0.6 Pa, and a deposition rate of 0.1 nm / s, for 50 s, resulting in a transition metal layer with a thickness of approximately 5 nm. After deposition, the resin film was kept at 60℃ for 30 minutes for low-temperature setting to obtain a resin film with a nano-metal layer on the surface.

[0074] A polyether-type aqueous polyurethane dispersion, gallium indium tin alloy, and fluorinated polyurethane were prepared at a mass ratio of 65:30:5. First, 65g of the polyether-type aqueous polyurethane dispersion and 5g of the fluorinated polyurethane were stirred at 500 rpm for 20 minutes at room temperature to obtain a pre-dispersion. Then, 30g of gallium indium tin alloy was added to the pre-dispersion, and the mixture was dispersed under ultrasonic power of 400W for 20 minutes to obtain a slurry mother liquor. The mother liquor was stirred at 600 rpm for 10 minutes to perform rheological regulation, controlling the slurry viscosity within the range of approximately 2000 mPa·s, thus obtaining a composite slurry.

[0075] The composite slurry is divided into a first slurry and a second slurry. In the first slurry, the liquid metal content is increased to 35 wt%, and the fluoropolymer content is reduced to 3 wt%; in the second slurry, the liquid metal content is reduced to 20 wt%, and the fluoropolymer content is increased to 8 wt%. First, the first slurry is coated onto the surface of the nano-metal layer using a blade coating method, controlling the coating thickness to approximately 20 μm, forming the first coating layer. Then, the second slurry is coated onto the surface of the first coating layer using a screen printing method, controlling the coating thickness to approximately 15 μm, forming the second coating layer. Subsequently, the process is carried out according to step S3.5, pre-drying at 90°C for 15 min, and then hot-pressing at 0.2 MPa for 40 s. This causes the liquid metal in the first coating layer to form a continuous heat-reflective surface under pressure, while the second coating layer forms a porous, protective, and breathable surface enriched with fluoropolymers, thus obtaining a composite heat-reflective layer with directional heat-reflective properties.

[0076] A mask with a lattice-pore structure was placed over the surface of the composite heat-reflective layer. Ethyl acetate was then applied to the exposed lattice-pore areas by spraying to soften them, with the solvent dosage controlled at 3 g / m². 2 The softening time is 20s; then the fiber lining is dried at 70℃ for 30min, and then the fiber lining and resin film are bonded under normal pressure, so that the fiber lining forms a local bond with the composite heat reflective layer in the dot matrix area, while the area not in contact with the solvent remains unbonded; finally, the composite structure is set at 60℃ for 30min to obtain a breathable metal composite textile.

[0077] Example 3: Weigh 860g of thermoplastic polyurethane as the thermoplastic matrix resin, 90g of 4,4'-oxobisbenzenesulfonyl hydrazine as a micropore regulator, and 50g of nano-silica as a reinforcing agent, with a mass ratio of 86:9:5. Dry the thermoplastic polyurethane at 80℃ for 6 hours, and dry the 4,4'-oxobisbenzenesulfonyl hydrazine and nano-silica at 60℃ for 4 hours. Then, mix the three materials in a high-speed mixer at 500 rpm for 6 minutes to obtain a primary mixture. Add the primary mixture to a twin-screw extruder for melt mixing. Set the extruder temperature zones to 150℃, 160℃, 170℃, and 180℃, the screw speed to 150 rpm, and allow the material to remain in the barrel for approximately 3 minutes, maintaining a constant temperature in the vacuum exhaust section. A negative pressure of 0.08 MPa was applied. The film was then extruded through a casting die at 160°C and a cooling roller temperature of 25°C, yielding a resin film approximately 40 μm thick. One side of the resin film was then surface-activated in an RF plasma treatment at 100 W for 30 seconds in an oxygen atmosphere, resulting in the activated side of the resin film.

[0078] The resin film is fixed on the substrate tray of the vacuum deposition equipment with the activated side facing upwards, and the cavity is evacuated to 5×10⁻⁶. -4 mbar. Argon gas was introduced into the chamber at a flow rate of 30 sccm and a working pressure of 0.5 Pa, followed by ion cleaning at 80 W RF power for 40 s. A metal seed layer was then deposited using a titanium target via magnetron sputtering at a power of 100 W for 20 s, forming a seed layer approximately 5 nm thick. Next, a main metal layer was deposited using aluminum as the main metal via evaporation deposition at a rate of 0.2 nm / s and a heating power of 200 W, forming a main metal layer approximately 30 nm thick. Finally, a transition metal layer was deposited using nickel as the transition metal via magnetron sputtering at a DC sputtering power of 120 W for 40 s, forming a transition metal layer approximately 8 nm thick. After deposition, the film was cryogenically set at 60 °C for 30 min to obtain a resin film with a nano-metal layer on its surface.

[0079] First, 700g of a polyether-type aqueous polyurethane dispersion and 80g of a fluorinated acrylic copolymer were weighed and stirred at 500 rpm for 20 min at room temperature to obtain a pre-dispersion. Then, 220g of gallium indium tin alloy liquid metal was added to the pre-dispersion, and the mixture was dispersed under ultrasonic power of 500W for 20 min to obtain a slurry mother liquor. Afterward, the mixture was stirred at 600 rpm for 10 min to stabilize the slurry viscosity at approximately 2000 mPa·s, yielding a composite slurry.

[0080] First, a first slurry was prepared: 325g of an aqueous polyurethane dispersion, 150g of gallium indium tin alloy liquid metal, and 25g of a fluorinated acrylic copolymer were mixed in a mass ratio of 65:30:5. Then, a second slurry was prepared: 350g of an aqueous polyurethane dispersion, 100g of gallium indium tin alloy liquid metal, and 50g of a fluorinated acrylic copolymer were mixed in a mass ratio of 70:20:10. 25g of ethyl acetate was added to the second slurry as a pore-forming auxiliary component, with an amount approximately 5wt% of the total mass of the second slurry. The first slurry was first coated onto the surface of the nano-metal layer using a blade coating method, with a coating amount of approximately 25g / m², forming a first coating layer with a thickness of approximately 15μm. Then, the second slurry was coated onto the surface of the first coating layer, with a coating amount of approximately 35g / m², forming a second coating layer with a thickness of approximately 20μm. Afterwards, a pre-drying treatment is performed, which involves drying at 110℃ for 20 minutes to allow ethyl acetate to evaporate and form a microporous structure in the second coating layer. Then, it is hot-pressed at 0.8MPa for 60 seconds to form a continuous heat-reflective surface in the first coating layer and a porous, breathable surface in the second coating layer, thereby obtaining a composite heat-reflective layer with directional heat-reflective properties.

[0081] A mask with a lattice-pore structure is applied to the surface of the composite heat-reflective layer. Ethyl acetate, a selective solvent, is then applied to the exposed lattice-pore areas via spraying at a rate of approximately 3 g / m². 2 The softening time was 20 seconds. Subsequently, the polyester fiber fabric was used as a fiber lining and dried at 60°C for 30 minutes before being bonded to the resin film under normal pressure. This allowed the fiber lining to partially bond with the composite heat-reflective layer in the dot matrix areas, while the areas not in contact with the solvent remained unbonded. After bonding, the composite structure was subjected to a setting treatment at 60°C for 30 minutes, ultimately yielding a breathable metal composite textile. This composite textile exhibits both excellent breathability and heat-reflecting and insulating properties.

[0082] Comparative Example 1: In step S4.1, instead of using a mask with a lattice aperture structure, ethyl acetate is applied at the same dosage of 3 g / m 2 The composite heat-reflective layer is applied to the entire surface of the resin film and softened for 20 seconds. Then, it is applied under normal pressure according to S4.2 of Example 1 and shaped according to S4.3.

[0083] Comparative Example 2: In step S3, the ratio of the composite slurry in Example 1 is adjusted from 65:30:5 (waterborne polyurethane dispersion: liquid metal: fluoropolymer) to 58:30:12, and the coating thickness of the composite slurry is increased from 20 μm to 30 μm. In step S4.1, a mask with a lattice pore structure is still used, but the amount of ethyl acetate is increased to 10 g / m³. 2The softening time was extended to 60 seconds, followed by normal pressure bonding according to S4.2 of Example 1 and shaping according to S4.3.

[0084] Air permeability test procedure: The prepared breathable metal composite textile was cut into circular samples with a diameter of 100 mm and placed at 23℃ and 50% relative humidity for 24 hours to achieve environmental equilibration. The samples were then mounted on the test fixture of the fabric air permeability tester, with the composite heat-reflective layer facing the airflow inlet. Airflow was measured under a pressure difference of 100 Pa. The volume of air passing through the sample per unit time was recorded during the test and converted to air permeability according to standard methods. Each sample was tested five times, and the average value was taken as the final result.

[0085] Water vapor transmission rate test procedure: A water vapor transmission rate testing device was used for the test. First, the sample was cut into a circular piece with a diameter of 80 mm and pretreated for 24 hours at 23℃ and 50% relative humidity. Then, the sample was sealed and fixed on a permeable cup containing a certain amount of deionized water, so that the composite textile formed a water vapor diffusion membrane. The assembled permeable cup was placed in a constant temperature and humidity chamber and placed at 38℃ and 50% relative humidity for 24 hours. The water vapor transmission rate was obtained by measuring the change in mass of the permeable cup before and after the test and converting it into the water vapor transmission rate per unit area per unit time.

[0086] Infrared reflectance testing procedure: The infrared reflectance performance of the samples was tested using a Fourier transform infrared spectrometer equipped with an integrating sphere attachment. Breathable metal composite textile samples were cut into 50mm × 50mm pieces and fixed on the sample stage, with the composite heat-reflective layer facing the infrared incident direction. Reflectance spectra were scanned within the wavelength range of 2.5–25 μm, and the reflectance at different wavelengths was recorded. The reflectance of the main human body thermal radiation wavelength range of 8–14 μm was integrated and averaged to obtain the infrared reflectance of the sample. Each sample was tested three times, and the average value was taken.

[0087] The heat retention rate test procedure was as follows: A constant-temperature heating plate was used to simulate the human body's heat source. The heating plate temperature was set to 35℃, and a heat flux sensor was placed on its surface. A breathable metal composite textile was then placed over the heating plate, with the composite heat-reflective layer facing the heat source. The heat flux density lost through the fabric to the external environment under steady-state conditions was recorded and compared with the heat flux density without the fabric covering. The heat retention rate was calculated based on the difference to evaluate the fabric's ability to reflect and retain heat from the human body's thermal radiation.

[0088] Surface resistance testing procedure: A four-probe surface resistance meter was used for measurement. The sample was cut into 50mm × 50mm square specimens and equilibrated for 24 hours at 23℃ and 50% relative humidity. The specimens were then laid flat on an insulating platform, ensuring the probes made uniform contact with the composite heat-reflective layer surface. The surface resistance value was measured using the four-probe method. Each sample was tested five times at different locations, and the average value was taken as the surface resistance of that sample.

[0089] Bending stability test procedure: The breathable metal composite textile was cut into 100mm × 20mm strip samples and mounted on a fabric bending fatigue testing machine. Cyclic bending tests were conducted at a bending angle of 180° and a bending frequency of 60 times / min, accumulating 1000 bends before stopping the test. The surface resistance of the samples was measured using the four-probe method before and after bending, and the rate of change of resistance was calculated to evaluate the stability of the composite heat-reflective layer under repeated mechanical deformation conditions.

[0090] The experimental data obtained from the above experiment are shown in Table 1.

[0091] Table 1: The experimental data show that Examples 1-3 all exhibit significantly better overall performance than Comparative Examples 1 and 2. In Example 1, a composite slurry was prepared using a waterborne polyurethane dispersion: liquid metal: fluoropolymer = 65:30:5, and the coating thickness was controlled to 20 μm. Simultaneously, the amount of ethyl acetate was limited to 3 g / m² using a dot-matrix mask. 2 The softening time is limited to 20 seconds, ensuring that the fiber lining only forms localized adhesion to the composite heat-reflective layer in the lattice pore area. This method utilizes the continuous waterborne polyurethane phase in the composite heat-reflective layer to generate localized self-adhesion, while avoiding additional adhesive layers or excessive solvents from blocking the micropores of the resin film. Therefore, the air permeability reaches 145 mm / s, and the water vapor transmission rate reaches 4820 g / m². 2 • 24h. Comparative Example 1, instead of using a mask plate to form a lattice structure, involved softening and bonding the entire surface, resulting in a large-area continuous bonding of the composite structure. This compacted the fiber structure and blocked some micropores, causing the air permeability to decrease to 48mm / s and the water vapor transmission rate to decrease to 1850g / m². 2 • 24h. Comparative Example 2 retained the lattice-hole structure of the mask, but increased the proportion of fluoropolymer to 12 parts by mass and thickened the composite heat-reflective layer to 30 μm, while increasing the amount of ethyl acetate to 10 g / m². 2The softening time was extended to 60 seconds. These changes caused excessive enrichment of the fluoropolymer on the surface, making the composite heat-reflective layer denser. Furthermore, ethyl acetate excessively swelled in the lattice pore region and diffused outwards, expanding the originally discrete dot-like bonding areas into semi-continuous bonding bands, thereby obscuring the microporous structure and air channels between fibers. Therefore, the air permeability of Comparative Example 2 decreased to 82 mm / s, and the water vapor permeability decreased to 2750 g / m². 2 • 24h; Simultaneously, due to excessive swelling and disturbance at the interface between the liquid metal microstructure and the nano-metal layer, the infrared reflectivity decreased to 76.4%, the heat retention rate decreased to 63.1%, and the resistance change rate after 1000 bends increased to 18.9%. These results demonstrate that the inventiveness of this invention lies not in simply using a lattice mask, but in the synergistic control of the composite slurry composition, coating thickness, and selective solvent softening window, thereby maintaining micropore connectivity and bending stability while preserving heat reflection functionality. Example 2 further constructs an asymmetric composite heat-reflective layer through a layered coating method, enriching the liquid metal near the nano-metal layer to form a continuous reflective surface, while the outer side has a higher fluoropolymer content to form a protective breathable layer structure, thus significantly improving infrared reflectivity while maintaining breathability. Experimental data show that Example 2 achieves an infrared reflectivity of 86.7%, while the heat retention rate increases to 74.8%. Example 3, based on Example 2, further incorporates ethyl acetate, a low-boiling-point organic solvent, as a pore-forming aid in the second slurry. This allows the second coating layer to form more microporous structures during the pre-drying process, thereby further improving the air and water vapor transmission channels. Experimental results show that the air permeability of Example 3 is increased to 168 mm / s, and the water vapor transmission rate reaches 5380 g / m³. 2 • 24h, while the infrared reflectivity remains at a relatively high level of 87.9%.

[0092] In summary, through the synergistic design of the dot matrix composite structure, the asymmetric layered heat-reflective structure, and the pore-forming auxiliary components, not only can the fabric's air and water vapor transmission capacity be maintained, but also a highly efficient infrared heat-reflective structure can be formed, thereby achieving a breathable metal composite textile that balances breathability and heat preservation performance.

[0093] For the manufactured breathable metal composite textiles, the residual amounts of organic solvents and fluoropolymers used need to be determined, and the determination steps are as follows.

[0094] Methods for determining organic solvents: First, a representative sample is cut from the finished breathable metal composite textile, avoiding obvious wrinkles, seams, and contaminated areas. The sample is then cut into smaller pieces and mixed thoroughly. 1.0 g–2.0 g of the sample is weighed and placed in a headspace vial, with an appropriate amount of diluent added. If using the external standard method, the vial can be sealed directly for analysis; if using the internal standard method, a quantitative internal standard solution is added before sealing. The headspace vial is then placed in an autosampler and equilibrated at 80–120 °C for 20–40 min to allow residual solvents in the sample to enter the gas phase. After equilibration, headspace gas is extracted and injected into a gas chromatograph. Separation is performed using a capillary column, and the results are determined using a flame ionization detector or mass spectrometer. The residual amount of each target solvent in the sample is calculated based on the standard curve, and the results are expressed in mg / kg.

[0095] Determination methods for fluoropolymers: First, a representative sample is cut from the finished breathable metal composite textile, shredded and mixed thoroughly. 50mg–200mg of the sample is then placed in a combustion boat. The sample is placed in a tube furnace and burned at high temperature under oxygen conditions, converting all organic and inorganic fluorine in the sample into absorbable fluoride ions, and absorbing the combustion products into the absorbent. Subsequently, the fluoride ion concentration in the absorbent is determined using ion chromatography, and the total fluoride content is calculated based on the sample weight. The result is expressed in mg / kg.

[0096] The measurement results are shown in Table 2.

[0097] Table 2: In one embodiment, if the ethyl acetate content exceeds the standard after bonding, a post-treatment for volatilization can be performed: first, the breathable metal composite textile is set at 60°C for 30 minutes, then subjected to hot air circulation at 80°C for 15 minutes, and if necessary, maintained under a negative pressure of -0.06 MPa for 10 minutes to promote further volatilization of residual ethyl acetate. If the fluorine content exceeds the standard, the breathable metal composite textile is post-treated as follows: the bonded and set breathable metal composite textile is immersed in deionized water at 30–50°C for 5–20 minutes, or sprayed with deionized water at 30–50°C, with the cleaning solution volume being 5–20 times the weight of the textile. The breathable metal composite textile after being cleaned with deionized water is then placed in an ethanol-water mixture for 3–15 minutes, with the ethanol volume fraction in the ethanol-water mixture being 10%–40%. To reduce the content of migratory fluoride residues, the breathable metal composite textiles are washed in a sodium bicarbonate or sodium carbonate aqueous solution with a pH of 7.5–9.0 for 2–10 minutes. After washing, they are dried under hot air at 50–80°C for 10–40 minutes, or under vacuum at 40–70°C for 10–60 minutes.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a breathable metal composite textile, characterized in that the steps include... include: S1. Prepare a resin film with a microporous structure, and activate one side of the resin film with the microporous structure to obtain the activated side of the resin film. S2. Deposit metal material on the activated side of the resin film using a metal target to form a nano-metal layer on the activated side; S3. A composite slurry containing liquid metal, waterborne polyurethane dispersion and fluoropolymer is coated onto the surface of the nano-metal layer, and after heat treatment, a composite heat reflective layer is obtained. The composite slurry is divided into a first slurry and a second slurry; Step S3 includes: taking 325g of water-based polyurethane dispersion, 150g of gallium indium tin alloy liquid metal, and 25g of fluorinated acrylic copolymer and mixing them in a mass ratio of 65:30:5 to obtain the first slurry; 350g of waterborne polyurethane dispersion, 100g of gallium indium tin alloy liquid metal and 50g of fluorinated acrylic copolymer were mixed in a mass ratio of 70:20:10 to obtain a second slurry. 25g of ethyl acetate was added to the second slurry as a pore-forming auxiliary component. First, the first slurry is coated onto the surface of the nano-metal layer by a scraping method, with a coating amount of 25 g / m². 2 A first coating layer with a thickness of 15 μm is formed, and then a second slurry is applied to the surface of the first coating layer, with a coating amount of approximately 35 g / m. 2 A second coating layer with a thickness of 20 μm is formed, followed by pre-drying treatment. The coating layer is dried at 110 °C for 20 min to volatilize ethyl acetate and form a microporous structure in the second coating layer. Then, it is hot-pressed at 0.8 MPa for 60 s to form a continuous heat reflective surface in the first coating layer and a porous and breathable surface in the second coating layer, thus obtaining a composite heat reflective layer. S4. The composite heat-reflective layer of fiber lining and resin film is composited in a dot matrix manner, with the fiber lining and resin film only bonded in dotted areas. After shaping treatment, a breathable metal composite textile is obtained. Step S4 includes: S4.

1. A mask with a lattice-hole structure is placed over a resin film composite heat-reflective layer. A selective solvent is applied to the exposed lattice-hole areas by spraying or roller coating to soften the layer. The selective solvent is used to soften the waterborne polyurethane continuous phase in the composite heat-reflective layer, causing the fiber lining to locally bond with the composite heat-reflective layer in the lattice-hole areas. The selective solvent is ethyl acetate, and the amount of selective solvent is controlled at 3 g / m³. 2 ; S4.2 Dry the fiber lining at 50~80℃, and then bond the fiber lining to the resin film under normal pressure so that the fiber lining forms a local bond with the composite heat reflective layer in the dot matrix area, while no bond is formed in the areas that are not in contact with the solvent. S4.3 After lamination, the composite structure is placed at 60-90℃ for shaping treatment to obtain breathable metal composite textile.

2. The method for preparing a breathable metal composite textile according to claim 1, characterized in that, Step S1 includes: S1.1 The thermoplastic matrix resin, micropore regulator and reinforcing agent are dried, and the thermoplastic matrix resin, micropore regulator and reinforcing agent are mixed at 300~800r / min according to the preset mass ratio to obtain a primary mixture; S1.

2. Add the primary mixture to the screw extruder for melt mixing. Set the temperature of each zone of the extruder to 120~190℃, control the screw speed at 80~250 r / min, and maintain it in the vacuum exhaust section. 0.06~ A negative pressure of 0.09 MPa was applied to obtain a molten homogeneous mixture; S1.

3. The molten homogeneous mixture is extruded into a film through a casting die, and the die temperature is controlled at 130~200℃ and the cooling roller temperature is 15~35℃ to obtain the resin film. During the cooling process, the resin film forms a microporous structure. S1.

4. Activate one side of the resin film by using radio frequency plasma equipment to obtain the activated side of the resin film.

3. The method for preparing a breathable metal composite textile according to claim 1 or 2, characterized in that, The thickness of the resin film is 10~80μm.

4. The method for preparing a breathable metal composite textile according to claim 2, characterized in that, In step S1, the thermoplastic matrix resin includes at least one of thermoplastic polyurethane, polyethylene, polypropylene, thermoplastic polyester elastomer, polyamide, and ethylene-vinyl acetate copolymer; the micropore regulator includes at least one of sodium bicarbonate, azodicarbonamide, and 4,4'-oxobisbenzenesulfonyl hydrazine; and the reinforcing agent includes at least one of nano silica, nano alumina, talc, transparent toughening resin, acrylic copolymer, polycarbonate microparticles, and styrene block copolymer.

5. The method for preparing a breathable metal composite textile according to claim 4, characterized in that, The mass ratio of thermoplastic matrix resin: micropore regulator: reinforcing agent is (82~91): (6~12): (3~6).

6. The method for preparing a breathable metal composite textile according to claim 1, characterized in that, Step S2 includes: S2.

1. Fix the resin film onto the substrate tray of the vacuum deposition equipment with the activated side facing upwards. Evacuate the cavity of the vacuum deposition equipment to a depth of 1×10⁻⁶. -3 ~1×10 -5 mbar; S2.

2. Argon or a mixture of argon and oxygen is introduced into the vacuum deposition equipment, and the gas flow rate is controlled at 10~50 sccm, the working pressure is 0.2~1.0 Pa, and the radio frequency power is 20~150 W to perform in-situ ion cleaning treatment on the resin film. S2.3 The metal target material includes a metal seed material, a main metal, and a transition metal. The metal seed material is first deposited on the activated side surface of the resin film by magnetron sputtering with a sputtering power of 30~200W and a working pressure of 0.2~1.0Pa to obtain a metal seed material layer. S2.

4. Deposit the main metal layer on the metal seed material layer by evaporation deposition, with a heating power of 50~400W, a working gas pressure of 0.2~1.5Pa, and a deposition rate of 0.05~1.0nm / s to obtain the main metal layer. S2.

5. Deposit a transition metal layer on the surface of the main metal layer by magnetron sputtering. The working pressure is controlled within the range of 0.2~1.0Pa, the DC sputtering power is 50~250W, and the deposition rate is controlled within the range of 0.02~0.5nm / s to obtain the transition metal layer. S2.6 After the metal seed material layer, main metal layer and transition metal layer are deposited, they are combined to form a nano metal layer. The deposited resin film is subjected to low temperature shaping treatment and kept at 90-130℃ to obtain a resin film with a nano metal layer on the surface.

7. The method for preparing a breathable metal composite textile according to claim 6, characterized in that, The thickness of the metal seed material layer is controlled within 1~10nm, the thickness of the main metal layer is controlled within 5~60nm, and the thickness of the transition metal layer is controlled within 1~15nm.

8. A method for preparing a breathable metal composite textile according to claim 6 or 7, characterized in that, In step S2, the seed metal material includes at least one of nickel, titanium, chromium, molybdenum, tantalum, and zirconium; the main metal includes at least one of aluminum, copper, silver, gold, zinc, and tin; and the transition metal includes at least one of nickel, titanium, chromium, stainless steel alloy, molybdenum, and tantalum.

9. A breathable metal composite textile, characterized in that, It is made by the method of preparing a breathable metal composite textile as described in any one of claims 1-8.

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