A thermal insulation fabric and its production method

Abstract

This application relates to the textile field, specifically disclosing a thermal insulation fabric and its production method. The thermal insulation fabric comprises, from the outside in, a PTFE garment film, an adhesive layer, a polyethersulfone / polyurethane mixed fiber wadding, a hollow PBT core-sheath composite fiber layer, an adhesive layer, and a polyurethane / zirconia aerogel composite fiber layer. The polyurethane / zirconia aerogel composite fiber layer is woven from polyurethane / zirconia aerogel composite fibers, which have a core-sheath structure. It is prepared by coaxial wet spinning of the sheath solution and the core solution, followed by impregnation in a tert-butanol aqueous solution, pre-freezing, and freeze-drying. The sheath solution is a polyurethane solution, and the core solution is a polyurethane solution containing zirconia aerogel powder, with a mass ratio of zirconia aerogel powder to polyurethane of 0.2-0.3:1. The thermal insulation fabric of this application has the advantages of good thermal insulation effect, high mechanical strength, high compression resilience, and relatively fluffy texture.

Description

Technical Field

[0001] This application relates to the field of textile technology, and more specifically, to a thermal insulation fabric and a method for producing the same. Background Technology

[0002] When the human body is exposed to low temperatures for an extended period, heat exchange occurs between the body and the external environment, leading to heat loss and potentially causing hypothermia, frostbite, cardiovascular diseases, and even endangering life. Therefore, maintaining a constant body temperature in low-temperature environments is a crucial issue for humanity. Fiber materials offer advantages such as comfort, readily available raw materials, and low cost, making them the most widely used insulation materials. However, existing natural fiber insulation materials are prone to moisture absorption, and their insulation performance decreases significantly after moisture absorption. Furthermore, their relatively large fiber diameter (typically >20μm) results in poor insulation performance. Synthetic fiber insulation materials have low thermal conductivity and good hydrophobicity, offering improved insulation performance compared to natural materials. However, they are typically composed of short, combed fibers, resulting in insufficient mechanical properties. Their fiber diameter (greater than 10μm) also limits further improvements in insulation performance.

[0003] In the prior art, Chinese invention patent document with application number CN01112926.3 discloses a method for manufacturing a windproof and warm fabric, including: (1) spinning process: the blending ratio (weight percentage) of the yarn is microfiber: conventional fiber = 70~100: 0~30, the tex twist coefficient of the yarn is 0~150, and the linear density of the yarn is 12~20tex; (2) weaving process: both the warp and weft yarns of the fabric are made of microfiber yarn, or the warp or weft yarns can be made of microfiber yarn alone; (3) dyeing and finishing process: high temperature and high pressure relaxation (scouring) → low tension drying → pre-setting → low tension alkali reduction → liquid flow dyeing → low tension drying → re-setting.

[0004] The aforementioned technology discloses the use of microfiber and conventional fiber mixed evenly in a certain proportion as warp and / or weft yarns. Although microfiber has advantages such as small diameter, small pore size and high porosity, the improvement in the heat retention performance of fabrics made by mixing microfiber and conventional fiber is limited and cannot meet people's demand for efficient heat retention. Summary of the Invention

[0005] In order to make the fabric have both excellent mechanical properties and efficient heat retention, this application provides a heat-insulating fabric and a method for producing the same.

[0006] In a first aspect, this application provides a thermal insulation fabric, which adopts the following technical solution:

[0007] A thermal insulation fabric, comprising, from the outside to the inside, a PTFE garment membrane, an adhesive layer, a polyethersulfone / polyurethane mixed fiber wadding, a hollow PBT core-sheath composite fiber layer, an adhesive layer, and a polyurethane / zirconia aerogel composite fiber layer.

[0008] The polyurethane / zirconia aerogel composite fiber layer is made by weaving polyurethane / zirconia aerogel composite fibers.

[0009] The polyurethane / zirconia aerogel composite fiber has a core-sheath structure and is prepared by wet spinning of the sheath solution and the core solution in a coaxial manner, followed by impregnation with an aqueous tert-butanol solution, pre-freezing, and freeze-drying.

[0010] The skin layer solution is a polyurethane solution with a concentration of 15-20 wt%.

[0011] The core layer solution is a polyurethane solution containing zirconia aerogel powder at a concentration of 15-20 wt%, and the mass ratio of zirconia aerogel powder to polyurethane is 0.2-0.3:1.

[0012] By adopting the above technical solution, using hollow PBT core-sheath composite fiber as the matrix, and then connecting polyethersulfone / polyurethane mixed fiber flakes and PTFE clothing film on the outside, and connecting polyurethane / zirconia aerogel composite fiber layer in the inner layer with adhesive, the hollow structure of the hollow PBT core-sheath composite fiber can store air with low thermal conductivity, significantly improving thermal barrier properties. Moreover, the hollow PBT core-sheath composite fiber has the advantage of being lightweight, making it more comfortable to wear.

[0013] The polyethersulfone / polyurethane mixed fiber flocs on the outer side of the hollow PBT core-sheath composite fiber layer are made of polyethersulfone and polyurethane as raw materials through electrospinning. Polyurethane provides the fiber with flexibility and abrasion resistance, while polyethersulfone enhances the fiber's tensile strength, resists external friction or stretching, reduces air convection, reduces heat loss, and increases the fabric's moisture permeability. The outermost PTFE clothing film has a high reflectivity to ultraviolet light and a low thermal conductivity, which can reduce heat loss. At the same time, the PTFE clothing film has a low coefficient of friction, a smooth surface, and excellent abrasion resistance. In addition, it also has good flexibility and tensile strength, which can improve the mechanical strength of the fabric.

[0014] The innermost polyurethane / zirconia aerogel composite fiber layer is mainly made of polyurethane / zirconia aerogel composite fibers with a core-sheath structure, woven together. Polyurethane serves as the sheath and polyurethane / zirconia aerogel powder as the core. Polyurethane has advantages such as flexibility and elasticity, ease of wet spinning, low hydrogen content, and good elasticity. As a sheath material, it can wrap the core layer, disperse stress when the fiber is under tension, and improve the fiber's elongation at break and tensile strength. Moreover, polyurethane also serves as the base material for the core polymer, working synergistically with the sheath to withstand certain stresses and enhance the fiber's rigidity and strength. Polyurethane also has excellent elastic recovery ability, capable of rapidly deforming under external compression and quickly returning to its original shape after the external force is removed. In addition, the polyurethane sheath and core layer can protect the structure of the zirconia aerogel, preventing it from being damaged during processing and use, thereby ensuring the stability of its thermal insulation performance.

[0015] As a core layer dopant, zirconia aerogel not only has a high far-infrared emissivity, but its nanoscale porous structure can also form a large number of micropores in the fiber, which can effectively inhibit the thermal conduction and convection of gas molecules. At the same time, the scattering effect of phonons by its pore walls further reduces the thermal conduction effect, making it difficult for heat to be transferred through the fiber and reducing heat loss. Moreover, the pores formed by zirconia aerogel in the fiber can also play a buffering role when the fiber is compressed, absorbing some energy and reducing excessive deformation of the fiber.

[0016] In the core layer, zirconia aerogel and polyurethane are uniformly dispersed and mixed. When the core layer solution is coaxially wet-spun, microscopic phase separation occurs in the system. During solvent exchange, the polyurethane molecular chains are displaced and shaped by water entering the gel fiber, forming a polymer skeleton. The zirconia aerogel adheres to the polymer skeleton and has good adhesion to it. Solvent exchange is performed using a tert-butanol aqueous solution, which enters the pore structure of the fiber through wetting. During freeze-drying, the tert-butanol solution is frozen, and then the tert-butanol is removed by freeze-drying. Using tert-butanol for solvent replacement avoids the formation of ice crystals during freeze-drying that would damage the polymer network structure and create macropores, thus disrupting the continuous network of the composite fiber. Therefore, the resulting polyurethane / zirconia aerogel composite fiber has high porosity and excellent mechanical properties. The construction of the porous structure makes the thermal conduction path of the polyurethane / zirconia aerogel composite fiber more tortuous, which is beneficial to increasing its interfacial thermal resistance and reducing overall thermal conductivity.

[0017] Optionally, the polyurethane / zirconia aerogel composite fiber is prepared as follows:

[0018] A polyurethane solution with a concentration of 15-20 wt% was used as the skin layer solution;

[0019] Zirconia aerogel powder was added to a polyurethane solution with a concentration of 15-20 wt%, and the solution was ultrasonicated to obtain a core layer solution. The mass ratio of zirconia aerogel powder to polyurethane was 0.2-0.3:1.

[0020] The cortex solution and core solution are coaxially wet-spun to obtain primary fibers;

[0021] The raw fibers were soaked in water, then immersed in a 25-30 wt% tert-butanol aqueous solution for 10-12 hours, pre-frozen, and then freeze-dried to obtain polyurethane / zirconia aerogel composite fibers.

[0022] By adopting the above technical solutions, the composite fibers produced by the above methods have a high porosity structure, which is beneficial to suppressing heat conduction, heat convection and heat radiation, thereby achieving high-efficiency heat preservation performance.

[0023] Optionally, the hollow PBT core-sheath composite fiber layer is obtained by needle punching hollow PBT core-sheath composite fibers. The raw material of the sheath layer in the hollow PBT core-sheath composite fiber is PBT, and the weight parts of the raw material of the core layer are as follows: 60-75 parts PBT, 20-35 parts TPU, 3-8 parts sodium bicarbonate, 1-3 parts compatibilizer, and 2-4 parts zirconium carbide.

[0024] By adopting the above technical solutions, hollow PBT core-sheath composite fibers, due to the high elastic modulus of PBT, have poor resilience and are prone to collapse after long-term compression, leading to a decrease in thermal insulation. Furthermore, the hollow structure is easily affected by pressure, impacting bulkiness and thermal insulation performance. Additionally, the hollow porous structure reduces overall strength. TPU, with its high elasticity, increases melt strength, making the cells less prone to rupture, improving foaming stability, and increasing pore uniformity and stability. Its toughening effect can compensate for the strength loss caused by the porous structure. Moreover, the synergy between TPU's elasticity and the porous structure allows the fiber to recover quickly after compression. The porous structure acts as an elastic energy storage unit, absorbing and releasing deformation energy, significantly improving compression resilience. It also stores still air, improving thermal insulation performance. The fabric exhibits excellent warmth retention. Compatibilizers are used to improve the compatibility between PBT and TPU, preventing phase separation. Zirconium carbide acts as a nucleating agent, refining the cell structure. It also possesses light-absorbing properties, enabling the fabric to perform photothermal conversion and provide additional heat to the human body. Sodium bicarbonate acts as a foaming agent, causing the core layer to form cells, thus creating PBT fibers with a hollow structure. This hollow structure provides better warmth retention. The PBT material in the core layer has good compatibility with the PBT in the sheath layer, enhancing the interfacial bonding between the core and sheath layers. The PBT in the sheath layer provides surface smoothness and mechanical strength to the fiber, protecting the porous structure of the core layer and preventing pore collapse. This results in a core-sheath composite fiber with a uniform cell structure, thereby improving compression recovery performance and thermal insulation efficiency.

[0025] Optionally, the method for preparing the hollow PBT core-sheath composite fiber includes the following steps:

[0026] Sodium bicarbonate and zirconium carbide were pretreated with silane coupling agent, PBT was dried and mixed with TPU, compatibilizer was added, and the mixture was hot melted, extruded and granulated to obtain blended granules.

[0027] The blended particles were mixed evenly with sodium bicarbonate and zirconium carbide pretreated with silane coupling agent to obtain the core material. PBT was used as the sheath material, and hollow PBT core-sheath composite fiber was obtained by twin-screw melting, extrusion, spinning, cooling, stretching and shaping and winding.

[0028] By adopting the above technical solution, sodium bicarbonate and zirconium carbide are pretreated with silane coupling agent to make them more uniformly dispersed with PBT and TPU, improve the compatibility between the components, prevent phase separation during foaming, make the cells more uniform, reduce cell rupture, and improve the fiber's warmth retention, resilience and moisture permeability.

[0029] Optionally, the core layer melt temperature is 240-255℃, the skin layer melt temperature is 230-250℃, the draw ratio is 1.5-1.6, and the spinning speed is 400-500m / min.

[0030] By adopting the above technical solution, controlling the melting temperature of the skin layer to be slightly lower than that of the core layer can maintain structural stability, prevent premature release of the foaming agent, and use an appropriate draw ratio to make the produced fiber have good strength.

[0031] Optionally, the compatibilizer is selected from at least one of styrene-acrylonitrile-GMA and styrene-maleic anhydride-glycidyl acrylate terpolymer.

[0032] By adopting the above technical solution, GMA in styrene-acrylonitrile-GMA (glycidyl methacrylate) and maleic anhydride in styrene-maleic anhydride-glycidyl acrylate terpolymer both contain reactive functional groups. The epoxy groups in GMA and the anhydride groups in maleic anhydride have high reactivity. In the blend system of PBT and TPU, these reactive groups can react chemically with the terminal hydroxyl and carboxyl groups of PBT and the amino and hydroxyl groups of TPU to form chemical bonds, thereby forming chemical bonds at the interface of PBT and TPU, enhancing the interaction force between the two phases and improving compatibility.

[0033] Optionally, the mass ratio of the skin layer material to the core layer material is 1-2:1.

[0034] By adopting the above technical solution, the hollow PBT core-sheath composite fiber prepared by melt online foaming with the core and sheath materials of the above ratio has a uniform cell distribution, and the foaming agent has enough space to expand, which can balance porosity and structural stability.

[0035] Optionally, the polyethersulfone / polyurethane mixed fiber wadding comprises, from the outside to the inside, a polyethersulfone fiber layer, a polyethersulfone / polyurethane mixed fiber layer, and a polyurethane fiber layer that are in sequential contact with each other and have a thickness ratio of 1:1 to 2:1.

[0036] By adopting the above technical solution, polyethersulfone (PES) has a large contact angle, while polyurethane has poor mechanical properties. Furthermore, PES has strong hydrophobicity, and its moisture permeability needs improvement. Therefore, a PES fiber layer is used as the outermost layer, which has good hydrophobicity and a dense structure. A blend of PES and polyurethane fibers is used as the middle layer, with PES providing rigid support and polyurethane providing elasticity. Its hydrophobicity is between that of PES and polyurethane fibers, forming a gradient transition interface. The innermost layer is polyurethane fiber with good moisture absorption and wicking properties, and it also has good resilience. Therefore, the hydrophobicity of the PES / polyurethane blended fiber sheet decreases from the outside to the inside, constructing a three-layer hydrophobic structure. The water gradient effect creates more moisture-permeable channels, allowing water vapor to pass through the wadding more easily, while better preventing external liquid water from entering the fabric. Therefore, the polyethersulfone fiber layer in the mixed fiber wadding blocks cold air convection and provides rigid support. The polyethersulfone / polyurethane mixed fibers form a microporous air-storing structure, and the polyurethane fiber layer maintains its bulkiness through elasticity, reducing the thermal conductivity. Moreover, the high elasticity of the polyurethane fiber layer dominates the recovery performance, enhances toughness, reduces permanent deformation, and prevents the polyethersulfone / polyurethane mixed fiber layer from collapsing as a whole. It has good resilience after multiple compressions, and the three-layer structure makes it easier to maintain bulkiness, retaining more refined air layers and providing stronger warmth retention.

[0037] Optionally, the raw materials for the polyethersulfone / polyurethane hybrid fiber include polyethersulfone, polyurethane, and capped isocyanate in a mass ratio of 1:4-6:2-2.5.

[0038] By adopting the above technical solution, using polyethersulfone and polyurethane as spinning raw materials, and adding a certain amount of end-capped isocyanate, the end-capped isocyanate will form a three-dimensional network structure with the polymer macromolecules, enhancing the mechanical properties of the fiber. Moreover, as an excellent elastomer, polyurethane can increase the elasticity and toughness of the polymer fiber, which is beneficial to improving the overall elasticity of the fiber, thereby obtaining a good three-dimensional fluffy structure, which is convenient for rebound after compression and reduces compression deformation. At the same time, the mixed fibers with a three-dimensional fluffy structure have less contact between them, and heat is difficult to be continuously transferred through the fiber itself. Heat is also conducted through the heat convection and heat transfer of the refined air inside the fiber. The fiber also separates the air into independent cavities, which limits the heat convection. Therefore, heat is difficult to transfer quickly, thus making the polyethersulfone / polyurethane mixed fiber have good thermal insulation properties.

[0039] Optionally, the adhesive is a water-based polyurethane adhesive, and the spraying amount is 10-20 g / m². 2 .

[0040] By adopting the above technical solution, water-based polyurethane adhesive is used for bonding. After curing, the solvent evaporates to form micropores, which have high elasticity and good moisture permeability, thus avoiding affecting the moisture permeability of the fabric. Polyvinyl alcohol is added to enhance its hydrophilicity, and nano-silica can enhance the stability of the pores and prevent collapse. The appropriate amount of adhesive sprayed can avoid the adhesive being too thick and clogging the pores.

[0041] Secondly, this application provides a method for producing thermal insulation fabric, which adopts the following technical solution:

[0042] A method for producing a thermal insulation fabric includes the following steps:

[0043] S1. Using polyurethane / zirconia aerogel composite fibers as warp and weft, weave to obtain a polyurethane / zirconia aerogel composite fiber layer. Then, needle-punch hollow PBT core-sheath composite fibers to obtain a hollow PBT core-sheath composite fiber layer.

[0044] S2. Electrospinning is performed on the polyurethane solution with a hollow PBT core-shell composite fiber layer as the receiving matrix to form a polyurethane fiber layer on the receiving matrix.

[0045] S3. Using the polyurethane fiber layer in step S2 as the receiving substrate, electrospinning the mixed spinning solution containing polyethersulfone, polyurethane and capped isocyanate, and thermally crosslinking at 80-120°C for 30-60 min to form a polyethersulfone / polyurethane mixed fiber layer on the polyurethane fiber layer.

[0046] S4. The polyethersulfone / polyurethane mixed fiber layer obtained in step S3 is used as a receiving substrate on one side. The polyethersulfone solution is electrospun to form a polyethersulfone fiber layer on the polyethersulfone / polyurethane mixed fiber layer.

[0047] S5. Spray adhesive on both sides of the material obtained in step S4, and bond the PTFE membrane to the polyethersulfone fiber layer, and bond the polyurethane / zirconia aerogel composite fiber layer to the hollow PBT core composite fiber layer. Hot press at 80-100℃ and 0.5-1MPa for 1-2 minutes to obtain the thermal insulation fabric.

[0048] By adopting the above technical solution, polyurethane / zirconia aerogel composite fibers are first woven into layers, then hollow PBT core-sheath composite fibers are needle-punched into layers. Next, on the hollow PBT core-sheath composite fiber layers, polyurethane fiber layers, polyethersulfone / polyurethane mixed fiber layers, and polyethersulfone fiber layers are sequentially deposited through electrospinning, thereby constructing a three-layer gradient structure. This improves the moisture permeability, compression resilience, and warmth retention of the thermal insulation fabric. Finally, an adhesive is used to bond the PTFE clothing film and the polyurethane / zirconia aerogel composite fiber layers to obtain a thermal insulation fabric suitable for use as linings in cold-weather clothing and bedding, as well as in building insulation materials and high-loft insulation layers for pipe insulation.

[0049] In summary, this application has the following beneficial effects:

[0050] 1. This application uses PTFE clothing film, polyethersulfone / polyurethane mixed fiber wadding, hollow PBT core-sheath composite fiber layer and polyurethane / zirconia aerogel composite fiber layer to prepare thermal insulation fabric. In the polyethersulfone / polyurethane mixed fiber wadding, polyethersulfone has strong tensile strength, which can reduce heat loss, while polyurethane provides toughness and improves compression resilience. The hollow structure of the hollow PBT core-sheath composite fiber can store air with low thermal conductivity, which significantly improves thermal barrier properties. Due to the introduction of zirconia aerogel, the polyurethane / zirconia aerogel composite fiber has a better microporous structure, which can inhibit heat conduction, thereby obtaining a fabric with outstanding thermal insulation effect. This fabric also has good compression resilience and moisture permeability.

[0051] 2. In this application, PBT is preferably used as the sheath, and PBT, TPU, sodium bicarbonate, silicon carbide, etc. are used as the core layer. Hollow PBT sheath-core composite fibers are prepared by hot melt extrusion, spinning and other processes. TPU can increase melt flow rate, improve pore wall strength, make the cells less prone to rupture, and increase cell uniformity and stability. At the same time, it has high elasticity, which can improve the mechanical strength and compression resilience of the fiber, so that the finished fiber has high porosity, increases the heat preservation effect, and also has high moisture permeability and resilience.

[0052] 3. The polyethersulfone / polyurethane mixed fiber wadding in this application comprises a polyethersulfone fiber layer, a polyethersulfone / polyurethane mixed fiber layer and a polyurethane fiber layer from the outside to the inside. The gradient design of the three-layer structure forms more moisture permeability channels, improves the resilience of the wadding, reduces permanent deformation, maintains fluffiness and improves the heat insulation effect. Detailed Implementation

[0053] The following embodiments provide a further detailed description of this application.

[0054] Example I: Zirconium oxynitrate and yttrium nitrate were dissolved in an alcohol-water mixed solvent (volume ratio of alcohol to water was 2:1) to prepare a zirconium salt solution with a concentration of 0.3 mol / L. The solution was stirred at 60 °C for 40 min, and formamide (molar ratio of zirconium to formamide was 1:1) was added. After stirring for 2 h, propylene oxide (molar ratio of zirconium to propylene oxide was 1:6) was added and stirred for 15 min. The solution was allowed to stand to form a gel and aged at 50 °C for 3 days. The solution was replaced with anhydrous ethanol every 24 h. The solution was placed in an autoclave and ethanol was used as the supercritical drying medium. Nitrogen gas was introduced to purge the air. The temperature was raised to 270 °C and held for 3 h. Nitrogen gas was then introduced to purge the tail gas. The solution was cooled to room temperature and then heat-treated in a muffle furnace at 400 °C for 3 h. The solution was then pulverized to 5 μm.

[0055] Preparation Examples of Polyurethane / Zirconium Oxide Aerogel Composite Fibers 1-3

[0056] In Preparation Examples 1-3, the polyurethane was selected from Bayer, Germany, model 9385A, and the zirconia aerogel powder was prepared from Preparation Example I of zirconia aerogel.

[0057] (1) Dissolve 15g of polyurethane in DMF solvent, stir at 85℃ for 4h, and sonicate for 15min to obtain a polyurethane solution with a concentration of 15wt%, which is the skin solution.

[0058] (2) Dissolve 15g of polyurethane in DMF solvent, stir at 85℃ for 4h, sonicate for 15min to obtain a polyurethane solution with a concentration of 15wt%, add 4.5g of zirconia aerogel powder, sonicate for 15min to obtain a core layer solution.

[0059] (3) The cortex solution and core solution are coaxially wet-spun to obtain primary fibers. The coagulation bath is deionized water. The outer diameter of the coaxial needle is 1.55 mm and the inner diameter is 0.7 mm. The cortex spinning speed is 0.35 ml / min, the core spinning speed is 0.25 ml / min, and the take-up speed is 0.02 m / s.

[0060] (4) Soak the raw fiber in water for 4 hours, then soak it in a 25wt% tert-butanol aqueous solution for 12 hours, pre-freeze it at -70℃ for 3 hours, and then freeze-dry it at -70℃ and 0.5MPa for 24 hours to obtain polyurethane / zirconia aerogel composite fiber.

[0061] Preparation Example 2: (1) Dissolve 20g of polyurethane in DMF solvent, stir at 85°C for 4h, and sonicate for 15min to obtain a polyurethane solution with a concentration of 20wt%, which is the skin solution;

[0062] (2) Dissolve 20g of polyurethane in DMF solvent, stir at 85℃ for 4h, sonicate for 15min to obtain a polyurethane solution with a concentration of 20wt%, add 4g of zirconia aerogel powder, sonicate for 15min to obtain a core layer solution.

[0063] (3) The cortex solution and core solution are coaxially wet-spun to obtain primary fibers. The coagulation bath is deionized water. The outer diameter of the coaxial needle is 1.55 mm and the inner diameter is 0.7 mm. The cortex spinning speed is 0.35 ml / min, the core spinning speed is 0.25 ml / min, and the take-up speed is 0.02 m / s.

[0064] (4) Soak the raw fiber in water for 4 hours, then soak it in a 30wt% tert-butanol aqueous solution for 10 hours, pre-freeze it at -70℃ for 3 hours, and then freeze-dry it at -70℃ and 0.5MPa for 24 hours to obtain polyurethane / zirconia aerogel composite fiber.

[0065] Preparation Example 3: 15g of polyurethane was dissolved in DMF solvent, stirred at 85℃ for 4h, and sonicated for 15min to obtain a polyurethane solution with a concentration of 15wt%. 4.5g of zirconia aerogel powder was added and sonicated for 15min to obtain a spinning solution. Electrospinning was performed to obtain polyurethane / zirconia aerogel composite fibers. The voltage during electrospinning was 25kV, the spinning speed was 4ml / h, and the receiving distance was 15cm.

[0066] Preparation Examples of Hollow PBT Core-Sheath Composite Fibers 4-7

[0067] In the following preparation examples, PBT is selected from Dongguan Gongsu Technology Co., Ltd., model B4520 from BASF, Germany, and TPU is selected from Shenzhen Haorui Plastics Co., Ltd., model A85P4394 from Huntsman.

[0068] Preparation Example 4: (1) 8g sodium bicarbonate and 4g zirconium carbide were mixed, and a silane coupling agent KH-550 mixed solution of ethanol and water (ethanol:water = 9:1, volume ratio) with a total amount of 20g and a concentration of 3wt% was added. After stirring at 90°C for 2h, the mixture was filtered, washed, and dried. The amount of silane coupling agent used was 5% of the total weight of sodium bicarbonate and zirconium carbide. Then, 75g PBT was dried at 120°C for 8h, mixed evenly with 35g TPU, and 3g compatibilizer styrene-acrylonitrile-GMA was added. After mixing, the mixture was heated to 250°C for hot melting, extrusion, and granulation to obtain blended granules.

[0069] (2) The blended particles were mixed evenly with sodium bicarbonate and zirconium carbide pretreated with silane coupling agent to obtain core material. PBT was used as skin material. The core material and skin material with a mass ratio of 1:1 were fed into a twin-screw extruder, melted, extruded, filaments were produced by the spinneret, cooled, drawn and shaped and wound to obtain hollow PBT core-skin composite fiber. The skin melting temperature was 250℃, the core melting temperature was 255℃, the draw ratio was 1.6, the spinning speed was 500m / min, and the screw speed was 20rpm.

[0070] Preparation Example 5: (1) 3g sodium bicarbonate and 2g zirconium carbide were mixed, and a silane coupling agent KH-550 mixed solution of ethanol and water (ethanol:water = 9:1, volume ratio) with a total amount of 8.33g and a concentration of 3wt% was added. After stirring at 90°C for 2h, the mixture was filtered, washed, and dried. The amount of silane coupling agent used was 5% of the total weight of sodium bicarbonate and zirconium carbide. Then, 60g PBT was dried at 120°C for 8h, mixed evenly with 20g TPU, and 1g compatibilizer styrene-maleic anhydride-glycidyl acrylate terpolymer was added. After mixing, the mixture was heated to 250°C for hot melting, extrusion, and granulation to obtain blended granules.

[0071] (2) The blended particles were mixed evenly with sodium bicarbonate and zirconium carbide pretreated with silane coupling agent to obtain core material. PBT was used as skin material. The core material and skin material with a mass ratio of 2:1 were fed into a twin-screw extruder, melted, extruded, filaments were produced by the spinneret, cooled, drawn and shaped and wound to obtain hollow PBT core-skin composite fiber. The skin melting temperature was 230℃, the core melting temperature was 240℃, the draw ratio was 1.5, the spinning speed was 400m / min, and the screw speed was 30rpm.

[0072] Preparation Example 6: The difference from Preparation Example 4 is that zirconium carbide was not added.

[0073] Preparation Example 7: The difference from Preparation Example 4 is that TPU, compatibilizer and zirconium carbide were not added to the core layer raw material. The specific method is as follows: (1) 8g of sodium bicarbonate was added to a 13.3g total amount and 3wt% concentration of silane coupling agent KH-550 in a mixture of ethanol and water (ethanol:water = 9:1, volume ratio). After stirring at 90°C for 2h, the mixture was filtered, washed and dried. The amount of silane coupling agent used was 5% of the amount of sodium bicarbonate used.

[0074] (2) 115g of PBT was dried at 120℃ for 8h and mixed evenly with sodium bicarbonate pretreated with silane coupling agent to obtain core material. PBT was used as sheath material. The core material and sheath material with a mass ratio of 1:1 were put into a twin-screw extruder, melted, extruded, filaments were produced by the spinneret, cooled, drawn and shaped and wound to obtain hollow PBT core-sheath composite fiber. The sheath melting temperature was 250℃, the core melting temperature was 255℃, the draw ratio was 1.6, the spinning speed was 500m / min, and the screw speed was 20rpm. Example

[0075] In the following examples, the polyurethane is selected from Shenzhen Haorui Plastics, model Huntsman A85P4394; the polyethersulfone is selected from Suzhou Changzhong Plastic Products, model BASF E3010; the waterborne polyurethane emulsion is selected from Anhui Dawei Huatai New Materials, model AH-1704C; and the polyvinyl alcohol is PVA-1788.

[0076] Example 1: A thermal insulation fabric comprising, from the outside to the inside, a PTFE garment film, an adhesive layer, a polyethersulfone / polyurethane mixed fiber wadding, a hollow PBT core-sheath composite fiber layer, an adhesive layer, and a polyurethane / zirconia aerogel composite fiber layer, which are in contact with each other in sequence. The polyurethane / zirconia aerogel composite fiber layer is made of polyurethane / zirconia aerogel composite fiber prepared in Example 1, and the hollow PBT core-sheath composite fiber is prepared in Example 4. The polyethersulfone / polyurethane mixed fiber wadding comprises, from the outside to the inside, a polyethersulfone fiber layer, a polyethersulfone / polyurethane mixed fiber layer, and a polyurethane fiber layer, which are in contact with each other in sequence with a thickness ratio of 1:1:1.

[0077] The production method of the above-mentioned thermal insulation fabric includes the following steps:

[0078] S1. Using polyurethane / zirconia aerogel composite fibers as warp and weft, a product with a thickness of 1.4 mm and a density of 18 g / m³ is produced through weaving. 2 The polyurethane / zirconia aerogel composite fiber layer consists of hollow PBT core-sheath composite fibers needle-punched at a density of 150 needles / cm². 2 A hollow PBT core-shell composite fiber layer with a thickness of 3mm;

[0079] S2. Dissolve polyurethane in DMF solvent, stir at 85℃ for 4 hours, and sonicate for 15 minutes to obtain a polyurethane solution with a concentration of 15wt%. Use hollow PBT core-sheath composite fiber layer as receiving matrix and electrospin to obtain polyurethane fiber layer on hollow PBT core-sheath composite fiber layer. The voltage during electrospinning is 30kV, the spinning speed is 2.5ml / h, and the receiving distance is 15cm.

[0080] S3. Polyethersulfone and polyurethane are added to DMAc in a certain mass ratio and stirred to dissolve, forming a solution with a polymer concentration of 20wt%. End-capped isocyanate is added and stirred for 4 hours to obtain a mixed spinning solution. The mass ratio of polyethersulfone, polyurethane and end-capped isocyanate is 1:4:2.5. Using the polyurethane fiber layer side of the product obtained in step S2 as the receiving substrate, the mixed spinning solution is electrospun and then crosslinked at 120°C for 30 minutes to form a polyethersulfone / polyurethane mixed fiber layer on the polyurethane fiber layer. The spinning voltage is 30kV, the spinning speed is 3ml / h, the receiving distance is 25cm, the spinning environment humidity is 80%, and the temperature is 23°C.

[0081] S4. Dissolve polyethersulfone in DMAc to prepare a spinning solution with a concentration of 15%. Using one side of the polyethersulfone / polyurethane mixed fiber layer obtained in step S3 as the receiving substrate, perform electrospinning. The spinning voltage is 50kV, the receiving distance is 12cm, the relative humidity is 60%, and the spinning speed is 1.5m / min. A polyethersulfone fiber layer is formed on the receiving substrate, thereby obtaining a polyethersulfone / polyurethane mixed fiber flocculent sheet with a thickness of 1.6mm on the hollow PBT core-sheath composite fiber layer.

[0082] S5. Apply water-based polyurethane adhesive evenly to both sides of the material obtained in step S4, with a spraying amount of 20g / m². 2 The PFTE membrane was bonded to the polyethersulfone fiber layer, and the polyurethane / zirconia aerogel composite fiber layer was bonded to the hollow PBT core composite fiber layer. The mixture was then hot-pressed at 100℃ and 0.5MPa for 1 minute to obtain a thermal insulation fabric with a compacted thickness of 5.97mm. The waterborne polyurethane binder contained 94wt% waterborne polyurethane emulsion, 5wt% polyvinyl alcohol 2000 and 1wt% nano silica.

[0083] Example 2: A thermal insulation fabric comprising, from the outside to the inside, a PTFE garment film, an adhesive, a polyethersulfone / polyurethane mixed fiber wadding, a hollow PBT core-sheath composite fiber layer, an adhesive layer, and a polyurethane / zirconia aerogel composite fiber layer, which are in contact with each other in sequence. The polyurethane / zirconia aerogel composite fiber layer is made of polyurethane / zirconia aerogel composite fiber prepared in Example 2, and the hollow PBT core-sheath composite fiber is prepared in Example 5. The polyethersulfone / polyurethane mixed fiber wadding comprises, from the outside to the inside, a polyethersulfone fiber layer, a polyethersulfone / polyurethane mixed fiber layer, and a polyurethane fiber layer, which are in contact with each other in sequence with a thickness ratio of 1:2:1.

[0084] The production method of the above-mentioned thermal insulation fabric includes the following steps:

[0085] S1. Using polyurethane / zirconia aerogel composite fibers as warp and weft, a product with a thickness of 1.6 mm and a density of 15 g / m³ is produced through weaving. 2The polyurethane / zirconia aerogel composite fiber layer consists of hollow PBT core-sheath composite fibers needle-punched at a density of 200 needles / cm². 2 A hollow PBT core-shell composite fiber layer with a thickness of 3.2mm;

[0086] S2. Dissolve polyurethane in DMF solvent, stir at 85℃ for 4 hours, and sonicate for 15 minutes to obtain a polyurethane solution with a concentration of 15wt%. Use hollow PBT core-sheath composite fiber layer as receiving matrix and electrospin to obtain polyurethane fiber layer on hollow PBT core-sheath composite fiber layer. The voltage during electrospinning is 30kV, the spinning speed is 2.5ml / h, and the receiving distance is 15cm.

[0087] S3. Polyethersulfone and polyurethane are added to DMAc in a certain mass ratio and stirred to dissolve, forming a solution with a polymer concentration of 20wt%. End-capped isocyanate is added and stirred for 4 hours to obtain a mixed spinning solution. The mass ratio of polyethersulfone, polyurethane and end-capped isocyanate is 1:6:2. Using the polyurethane fiber layer side of the product obtained in step S2 as the receiving substrate, the mixed spinning solution is electrospun and then crosslinked at 80°C for 60 minutes to form a polyethersulfone / polyurethane mixed fiber layer on the polyurethane fiber layer. The spinning voltage is 30kV, the spinning speed is 3ml / h, the receiving distance is 25cm, the spinning environment humidity is 80%, and the temperature is 23°C.

[0088] S4. Dissolve polyethersulfone in DMAc to prepare a spinning solution with a concentration of 15%. Using one side of the polyethersulfone / polyurethane mixed fiber layer obtained in step S3 as the receiving substrate, perform electrospinning. The spinning voltage is 50kV, the receiving distance is 12cm, the relative humidity is 60%, and the spinning speed is 1.5m / min. A polyethersulfone fiber layer is formed on the receiving substrate, thereby obtaining a polyethersulfone / polyurethane mixed fiber flocculent sheet with a thickness of 1.4mm on the hollow PBT core-sheath composite fiber layer.

[0089] S5. Apply water-based polyurethane adhesive evenly to both sides of the material obtained in step S4, with a spraying amount of 10g / m². 2 The PFTE membrane was bonded to the polyethersulfone fiber layer, and the polyurethane / zirconia aerogel composite fiber layer was bonded to the hollow PBT core composite fiber layer. The mixture was then hot-pressed at 80°C and 1MPa for 2 minutes to obtain a thermal insulation fabric with a compacted thickness of 6.17 mm. The waterborne polyurethane binder contained 94 wt% waterborne polyurethane emulsion, 5 wt% polyvinyl alcohol 2000, and 1 wt% nano silica.

[0090] Example 3: A thermal insulation fabric, which differs from Example 1 in that the hollow PBT core-sheath composite fiber is made from Preparation Example 6.

[0091] Example 4: A thermal insulation fabric, which differs from Example 1 in that the hollow PBT core-sheath composite fiber is made from Preparation Example 7.

[0092] Example 5: A thermal insulation fabric, differing from Example 1 in that the polyethersulfone / polyurethane blended fiber wadding is made solely from polyethersulfone / polyurethane blended fibers, and the specific method for thermal insulation is as follows:

[0093] S1. Using polyurethane / zirconia aerogel composite fibers as warp and weft, a product with a thickness of 1.4 mm and a density of 18 g / m³ is produced through weaving. 2 The polyurethane / zirconia aerogel composite fiber layer consists of hollow PBT core-sheath composite fibers needle-punched at a density of 150 needles / cm². 2 A hollow PBT core-shell composite fiber layer with a thickness of 3.2mm;

[0094] S2. Polyethersulfone and polyurethane were added to DMAc and stirred to dissolve, forming a solution with a polymer concentration of 20wt%. End-capped isocyanate was added and stirred for 4 hours to obtain a mixed spinning solution. The mass ratio of polyethersulfone, polyurethane and end-capped isocyanate was 1:4:2.5. Using a hollow PBT core-sheath composite fiber layer as the receiving substrate, the mixed spinning solution was electrospun and then crosslinked at 120℃ for 30 minutes to form a polyethersulfone / polyurethane mixed fiber layer on the hollow PBT core-sheath composite fiber layer, thus obtaining a polyethersulfone / polyurethane mixed fiber flocculent sheet with a thickness of 1.6 mm. The spinning voltage was 30 kV, the spinning speed was 3 ml / h, the receiving distance was 25 cm, the spinning environment humidity was 80%, and the temperature was 23℃.

[0095] S3. Apply water-based polyurethane adhesive evenly to both sides of the material obtained in step S2, with a spraying amount of 20g / m². 2 The PFTE membrane was bonded to the polyethersulfone / polyurethane hybrid fiber layer, and the polyurethane / zirconia aerogel composite fiber layer was bonded to the hollow PBT core composite fiber layer. The mixture was then hot-pressed at 100℃ and 0.5MPa for 1 minute to obtain a thermal insulation fabric with a compacted thickness of 5.97mm. The waterborne polyurethane binder contained 94wt% waterborne polyurethane emulsion, 5wt% polyvinyl alcohol 2000, and 1wt% nano silica.

[0096] Example 6: A thermal insulation fabric, differing from Example 1 in that the polyethersulfone / polyurethane mixed fiber wadding comprises a polyurethane fiber layer, a polyethersulfone / polyurethane mixed fiber layer, and a polyethersulfone fiber layer that are sequentially contacted from the outside to the inside with a thickness ratio of 1:1:1. The specific method for manufacturing the thermal insulation fabric is as follows:

[0097] S1. Using polyurethane / zirconia aerogel composite fibers as warp and weft, a product with a thickness of 1.4 mm and a density of 18 g / m³ is produced through weaving. 2The polyurethane / zirconia aerogel composite fiber layer consists of hollow PBT core-sheath composite fibers needle-punched at a density of 150 needles / cm². 2 A hollow PBT core-shell composite fiber layer with a thickness of 3mm;

[0098] S2. Polyethersulfone is dissolved in DMAc to prepare a spinning solution with a concentration of 15%. Hollow PBT core-sheath composite fiber layer is used as the receiving substrate for electrospinning. The spinning voltage is 50kV, the receiving distance is 12cm, the relative humidity is 60%, and the spinning speed is 1.5m / min. A polyethersulfone fiber layer is formed on the receiving substrate.

[0099] S3. Polyethersulfone and polyurethane are added to DMAc and stirred to dissolve, forming a solution with a polymer concentration of 20wt%. End-capped isocyanate is added and stirred for 4 hours to obtain a mixed spinning solution. The mass ratio of polyethersulfone, polyurethane and end-capped isocyanate is 1:4:2.5. Using the polyethersulfone fiber layer side of the product obtained in step S2 as the receiving substrate, the mixed spinning solution is electrospun and then crosslinked at 120°C for 30 minutes to form a polyethersulfone / polyurethane mixed fiber layer on the polyethersulfone fiber layer. The spinning voltage is 30kV, the spinning speed is 3ml / h, the receiving distance is 25cm, the spinning environment humidity is 80%, and the temperature is 23°C.

[0100] S4. Dissolve polyurethane in DMF solvent, stir at 85°C for 4 hours, and sonicate for 15 minutes to obtain a polyurethane solution with a concentration of 15wt%. Use the polyethersulfone / polyurethane mixed fiber layer obtained in step S3 as the receiving substrate and electrospin to form a polyurethane fiber layer on the receiving substrate. Thus, a polyethersulfone / polyurethane mixed fiber sheet with a thickness of 1.6 mm is obtained on the hollow PBT core-sheath composite fiber layer. The electrospinning voltage is 30 kV, the spinning speed is 2.5 ml / h, and the receiving distance is 15 cm.

[0101] S5. Apply water-based polyurethane adhesive evenly to both sides of the material obtained in step S4, with a spraying amount of 20g / m². 2 The PFTE membrane was bonded to the polyurethane fiber layer, and the polyurethane / zirconia aerogel composite fiber layer was bonded to the hollow PBT core composite fiber layer. The mixture was then hot-pressed at 100℃ and 0.5MPa for 1 minute to obtain a thermal insulation fabric with a compacted thickness of 5.97mm. The waterborne polyurethane binder contained 94wt% waterborne polyurethane emulsion, 5wt% polyvinyl alcohol 2000 and 1wt% nano silica.

[0102] Example 7: A thermal insulation fabric, differing from Example 1 in that the polyethersulfone / polyurethane mixed fiber wadding comprises a polyethersulfone fiber layer and a polyurethane fiber layer that are sequentially contacted from the outside to the inside and have a thickness ratio of 1:1. The specific method for manufacturing the thermal insulation fabric is as follows:

[0103] S1. Using polyurethane / zirconia aerogel composite fibers as warp and weft, a product with a thickness of 1.4 mm and a density of 18 g / m³ is produced through weaving. 2 The polyurethane / zirconia aerogel composite fiber layer consists of hollow PBT core-sheath composite fibers needle-punched at a density of 150 needles / cm². 2 A hollow PBT core-shell composite fiber layer with a thickness of 3mm;

[0104] S2. Dissolve polyurethane in DMF solvent, stir at 85℃ for 4 hours, and sonicate for 15 minutes to obtain a polyurethane solution with a concentration of 15wt%. Use hollow PBT core-sheath composite fiber layer as receiving matrix and electrospin to obtain polyurethane fiber layer on hollow PBT core-sheath composite fiber layer. The voltage during electrospinning is 30kV, the spinning speed is 2.5ml / h, and the receiving distance is 15cm.

[0105] S3. Dissolve polyethersulfone in DMAc to prepare a spinning solution with a concentration of 15%. Using the polyurethane fiber layer side of the product obtained in step S2 as the receiving substrate, perform electrospinning. The spinning voltage is 50kV, the receiving distance is 12cm, the relative humidity is 60%, and the spinning speed is 1.5m / min. A polyethersulfone fiber layer is formed on the receiving substrate, thereby obtaining a polyethersulfone / polyurethane mixed fiber flocculent sheet with a thickness of 1.6mm on the hollow PBT core-sheath composite fiber layer.

[0106] S4. Apply water-based polyurethane adhesive evenly to both sides of the material obtained in step S3, with a spraying amount of 20g / m². 2 The PFTE membrane was bonded to the polyethersulfone fiber layer, and the polyurethane / zirconia aerogel composite fiber layer was bonded to the hollow PBT core composite fiber layer. The mixture was then hot-pressed at 100℃ and 0.5MPa for 1 minute to obtain a thermal insulation fabric with a compacted thickness of 5.97mm. The waterborne polyurethane binder contained 94wt% waterborne polyurethane emulsion, 5wt% polyvinyl alcohol 2000 and 1wt% nano silica.

[0107] Comparative Example

[0108] Comparative Example 1: A thermal insulation fabric, which differs from Example 1 in that the polyurethane / zirconia aerogel composite fiber is made from Preparation Example 3.

[0109] Comparative Example 2: A thermal insulation fabric, differing from Example 1 in that it does not contain polyethersulfone / polyurethane mixed fiber wadding. The thermal insulation fabric, from the outside to the inside, comprises a PTFE membrane, an adhesive, a hollow PBT core-sheath composite fiber layer, an adhesive, and a polyurethane / zirconia aerogel composite fiber layer. The specific manufacturing method is as follows:

[0110] S1. Using polyurethane / zirconia aerogel composite fibers as warp and weft, a product with a thickness of 1.4 mm and a density of 18 g / m³ is produced through weaving. 2 The polyurethane / zirconia aerogel composite fiber layer consists of hollow PBT core-sheath composite fibers needle-punched at a density of 150 needles / cm². 2 A hollow PBT core-shell composite fiber layer with a thickness of 4.6 mm;

[0111] S2. Water-based polyurethane adhesive is uniformly sprayed onto both sides of the hollow PBT core-shell composite fiber layer, with a spraying amount of 20 g / m². 2 The PFTE membrane was bonded to the polyethersulfone fiber layer, and the polyurethane / zirconia aerogel composite fiber layer was bonded to the hollow PBT core composite fiber layer. The mixture was then hot-pressed at 100℃ and 0.5MPa for 1 minute to obtain a thermal insulation fabric with a compacted thickness of 5.97mm. The waterborne polyurethane binder contained 94wt% waterborne polyurethane emulsion, 5wt% polyvinyl alcohol 2000 and 1wt% nano silica.

[0112] Comparative Example 3: A thermal insulation fabric, differing from Example 1 in that it does not have a polyurethane / zirconia aerogel composite fiber layer. The thermal insulation fabric consists of, from the outside to the inside, a PTFE garment film, an adhesive, a polyethersulfone / polyurethane mixed fiber wadding, and a hollow PBT core-sheath composite fiber layer in contact with each other. The specific manufacturing method is as follows:

[0113] S1. The hollow PBT core-sheath composite fiber is needle-punched to a needle-punching density of 150 needles / cm². 2 A hollow PBT core-shell composite fiber layer with a thickness of 4.6 mm;

[0114] S2-S4 are the same as in Example 1;

[0115] S5. A water-based polyurethane adhesive is uniformly sprayed onto one side of the polyethersulfone fiber layer in the product obtained in step S4, with a spraying amount of 20 g / m². 2 The PFTE film was bonded to the polyethersulfone fiber layer and hot-pressed at 100℃ and 0.5MPa for 1 minute to obtain a thermal insulation fabric with a compacted thickness of 5.97mm. The waterborne polyurethane adhesive contained 94wt% waterborne polyurethane emulsion, 5wt% polyvinyl alcohol 2000 and 1wt% nano silica.

[0116] Performance testing

[0117] The thermal insulation fabrics were prepared according to the methods in the examples and comparative examples, and the performance was tested according to the following methods. The test results are recorded in Table 1.

[0118] 1. Moisture permeability test method: The test shall be conducted in accordance with the provisions of GB / T 12704-2009 "Determination of Moisture Permeability of Fabrics - Moisture Permeability Cup Method". The test temperature is 38℃ and the relative humidity is 90%. The moisture permeability is calculated according to the following formula: W=△m / (A·t), where W is the moisture permeability, g / (m 2 ·d), △m is the mass difference before and after moisture absorption, g; A is the effective test area, m2; t is the test time, d.

[0119] 2. Tensile strength: A UTM2203 universal testing machine was used. The fabric size was 10mm×40mm, the clamping distance was 250mm, the tensile rate was 500mm / min, and each sample was measured 3 times. The average value was taken.

[0120] 3. Loft: The test shall be conducted according to the method in Appendix A of FZ / T64003-2021 "Spray-bonded Cotton Wadding Sheets", i.e., take a 10cm×10cm (i.e., area 100cm²) sample. 2 The sample was pressurized with 0.02 kPa, and the initial thickness F0 (mm) was measured after 10 seconds. The sample weight m (accurate to 0.001 g) was also measured, and the bulkiness value (cm) was calculated. 3 / g)=10×F0 / m.

[0121] 4. Compression Resilience: Take a sample with dimensions of 30mm × 30mm. According to section 6.10 of FZ / T64006 standard, test the compression resilience of the sample, i.e., take a 10cm × 10cm sample (i.e., an area of ​​100cm²). 2 For a sample, apply a light pressure of 0.02 kPa and measure the initial thickness F0 (mm) after 10 seconds; increase the pressure to 1 kPa and measure the thickness Fh (mm) under heavy pressure after 1 minute; remove the pressure, allow it to recover for 1 minute, then apply light pressure again and measure the recovered thickness Fr (mm) after 10 seconds. The compression recovery rate (%) is calculated as (Fr - Fh) / (F0 - Fh) × 100%.

[0122] 5. Thermal insulation performance: The thermal conductivity of the fiber sponge was tested using a TPS-2500S thermal constant analyzer. Two samples of similar thickness were cut out, and the test probe was clamped in the middle of the two samples. A certain pressure was applied above the samples to ensure close contact between the test probe and the samples. The test program was set and the test was carried out. The thermal conductivity was then calculated. Each sample was measured 5 times at different positions. The test temperature was 20±2℃ and the relative humidity was 50-60%.

[0123] Table 1 Performance test results of thermal insulation fabrics

[0124]

[0125] As can be seen from the preparation of the thermal insulation fabrics in Examples 1-2 and the data in Table 1, the thermal insulation fabrics prepared in Examples 1-2 have high moisture permeability, high tensile strength, good bulkiness, high compression resilience, low thermal conductivity, high warmth retention and compression resilience, and are also relatively bulky and have high mechanical strength.

[0126] Compared with Example 1, Example 3 used hollow PBT core-sheath composite fibers prepared in Example 6. Compared with Example 4 in Example 1, no zirconium carbide was added in Example 6. It can be seen that the bulkiness of the thermal insulation fabric prepared in Example 3 decreased slightly, and the thermal conductivity increased, while the moisture permeability also decreased. This indicates that the addition of zirconium carbide can increase the structural stability of the voids in the hollow PBT core-sheath composite fibers, thereby improving moisture permeability, bulkiness, and thermal insulation.

[0127] In Example 4, the hollow PBT core-sheath composite fiber prepared in Preparation Example 7 was used. Compared with Preparation Example 1 in Example 1, no TPU, zirconium carbide, or compatibilizer was added to the core layer. Only PBT and sodium bicarbonate foaming agent treated with silane were used as the core layer raw materials. As can be seen from the data in Table 1, the resulting thermal insulation fabric had reduced moisture permeability, tensile strength, bulkiness, and compression resilience, while the thermal conductivity increased and the thermal insulation performance weakened. This indicates that adding TPU, zirconium carbide, and compatibilizer to the core layer can effectively improve the thermal insulation, moisture permeability, resilience, and bulkiness of the hollow PBT core-sheath composite fiber layer.

[0128] Compared with Example 1, Example 5 only contains polyethersulfone / polyurethane mixed fiber wadding and does not have a gradient structure. As shown in Table 1, the moisture permeability of the thermal insulation fabric prepared in Example 5 is significantly reduced, and the tensile strength, bulkiness and compression resilience are also reduced, while the thermal conductivity is increased, resulting in a decrease in the insulation effect. This indicates that using only the polyethersulfone / polyurethane mixed fiber layer as wadding will affect the moisture permeability, insulation effect and bulkiness of the thermal insulation fabric.

[0129] Compared with Example 1, in Example 6, the positions of the polyethersulfone fiber layer and the polyurethane fiber layer in the polyethersulfone / polyurethane mixed fiber wadding were interchanged, and the polyethersulfone fiber layer was placed near the hollow PBT core composite fiber layer. As shown in Table 1, the mechanical properties, bulkiness, and compression resilience of the thermal insulation fabric did not change much, but the moisture permeability was significantly reduced, and the thermal insulation effect was weakened.

[0130] Compared with Example 1, Example 7 is made of polyethersulfone / polyurethane mixed fiber wadding, which is composed of polyethersulfone fiber layer and polyurethane fiber layer, without the polyethersulfone / polyurethane mixed fiber layer in the middle. It can be seen that the thermal insulation fabric prepared in Example 7 has decreased tensile strength, bulkiness and compression resilience, decreased thermal insulation performance and decreased moisture permeability.

[0131] In Comparative Example 1, the polyurethane / zirconia aerogel composite fiber prepared in Preparation Example 3 was used. Compared with Example 1, the moisture permeability and compression resilience of the thermal insulation fabric decreased, the thermal conductivity increased, and the thermal insulation effect decreased.

[0132] Compared with Example 1, Comparative Example 2 did not include polyethersulfone / polyurethane mixed wadding, and hollow PBT core-sheath composite fibers were used to compensate for the thickness of the wadding. It can be seen that the compression resilience of the thermal insulation fabric made in Comparative Example 2 decreased, the moisture permeability weakened, and the thermal insulation effect decreased, but the tensile strength increased slightly. This indicates that although the hollow PBT core-sheath composite fiber layer has better rigidity, its effect on improving fluffiness, resilience, and moisture permeability is not as good as that of polyethersulfone / polyurethane mixed wadding.

[0133] Compared with Example 1, Comparative Example 3 did not have a polyurethane / zirconia aerogel composite fiber layer, and a hollow PBT core composite fiber layer was used to compensate for its thickness. It can be seen that the moisture permeability, bulkiness and compression resilience of the thermal insulation fabric decreased, the thermal conductivity increased, and the thermal insulation ability weakened.

[0134] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A thermal fabric, characterized by, The thermal insulation fabric sequentially includes a PTFE clothing film, an adhesive layer, a polyethersulfone / polyurethane hybrid fiber flake, a hollow PBT core-shell composite fiber layer, an adhesive layer, and a polyurethane / zirconia aerogel composite fiber layer from outside to inside; The polyethersulfone / polyurethane hybrid fiber flake includes a polyethersulfone fiber layer, a polyethersulfone / polyurethane hybrid fiber layer, and a polyurethane fiber layer that are sequentially in contact from outside to inside and have a thickness ratio of 1:1 - 2:1; The polyurethane / zirconia aerogel composite fiber layer is made by weaving polyurethane / zirconia aerogel composite fibers; The polyurethane / zirconia aerogel composite fiber has a core-shell structure and is prepared by coaxial wet spinning of a cortical solution and a core layer solution, followed by infiltration with a tert-butanol aqueous solution, pre-freezing, and freeze-drying; The cortical solution is a polyurethane solution with a concentration of 15 - 20 wt%; The core layer solution is a polyurethane solution containing zirconia aerogel powder with a concentration of 15 - 20 wt%, and the mass ratio of zirconia aerogel powder to polyurethane is 0.2 - 0.3:1; The hollow PBT core-shell composite fiber layer is made by needle punching hollow PBT core-shell composite fibers. In the hollow PBT core-shell composite fiber, the cortical raw material is PBT, and the weight parts of the core layer raw materials are as follows: 60 - 75 parts of PBT, 20 - 35 parts of TPU, 3 - 8 parts of sodium bicarbonate, 1 - 3 parts of compatibilizer, and 2 - 4 parts of zirconium carbide.

2. The thermal fabric of claim 1, wherein: The preparation method of the hollow PBT core-shell composite fiber includes the following steps: Pre-treat sodium bicarbonate and zirconium carbide with a silane coupling agent, dry PBT and mix it with TPU, add a compatibilizer, melt, extrude, and granulate to obtain a blended granule; Mix the blended granule with sodium bicarbonate and zirconium carbide pre-treated with a silane coupling agent evenly to obtain a core layer raw material. Use PBT as the cortical raw material, and through double-screw melting, extrusion, spinning, cooling, drawing and setting, and winding, obtain hollow PBT core-shell composite fibers.

3. The thermal fabric of claim 2, wherein: The melting temperature of the core layer raw material is 240 - 255 °C, the melting temperature of the cortical raw material is 230 - 250 °C, the drawing ratio is 1.5 - 1.6, and the spinning speed is 400 - 500 m / min.

4. The thermal fabric of claim 1, wherein: The compatibilizer is selected from at least one of styrene-acrylonitrile-GMA and styrene-maleic anhydride-glycidyl acrylate terpolymer.

5. The thermal fabric of claim 1, wherein: The mass ratio of the cortical raw material to the core layer raw material is 1 - 2:

1.

6. The thermal fabric of claim 1, wherein: The raw materials of the polyethersulfone / polyurethane hybrid fiber layer include polyethersulfone, polyurethane, and blocked isocyanate with a mass ratio of 1:4 - 6:2 - 2.

5.

7. The thermal fabric of claim 1, wherein: The binder is a waterborne polyurethane binder, the spraying amount is 10-20 g / m 2 .

8. The method for producing the thermal fabric according to any one of claims 1 to 7, characterized by: Include the following steps: S1. Use polyurethane / zirconia aerogel composite fibers as warp and weft, weave to obtain a polyurethane / zirconia aerogel composite fiber layer, and needle punch the hollow PBT core-shell composite fibers to obtain a hollow PBT core-shell composite fiber layer; S2. Use the polyurethane solution with the hollow PBT core-shell composite fiber layer as the receiving substrate, and electrospin to form a polyurethane fiber layer on the receiving substrate; S3. Taking the side of the polyurethane fiber layer in the product obtained in step S2 as the receiving substrate, electrospinning a mixed spinning solution containing polyethersulfone, polyurethane and blocked isocyanate, and performing thermal crosslinking treatment at 80 - 120 °C for 30 - 60 min to form a polyethersulfone / polyurethane mixed fiber layer on the polyurethane fiber layer; S4. Taking the side of the polyethersulfone / polyurethane mixed fiber layer in the product obtained in step S3 as the receiving substrate, electrospinning a polyethersulfone solution to form a polyethersulfone fiber layer on the polyethersulfone / polyurethane mixed fiber layer; S5. Spraying an adhesive on both sides of the product obtained in step S4, bonding a PTFE film to the polyethersulfone fiber layer, bonding a polyurethane / zirconia aerogel composite fiber layer to the hollow PBT core - sheath composite fiber layer, and performing hot pressing at 80 - 100 °C and 0.5 - 1 MPa for 1 - 2 min to obtain a warm - keeping fabric.

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