Gradient heat dissipation fabric

Abstract

The gradient heat dissipation fabric sequentially comprises a first functional layer, a fabric base material, a second functional layer and a third functional layer from inside to outside, the first functional layer is composed of a porous moisture absorption material, the second functional layer is composed of a plurality of protruding heat conduction components which are separated from one another, and moisture permeable areas exposed out of the base material are arranged among the components. The heat conduction component is composed of a polymer matrix and heat conduction filler, and the heat conduction coefficient is larger than that of a base material. The third functional layer is a continuous film conformally covering the second layer and the moisture permeable area of the second layer, the film has a phase transition temperature of 28-35 DEG C, and the infrared emissivity of the film at a low temperature is smaller than the infrared emissivity of the film at a high temperature. According to the gradient heat dissipation fabric adopting the technical scheme, the heat dissipation efficiency of the fabric from inside to outside can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation fabrics, and in particular to a gradient heat dissipation fabric. Background Art

[0002] In order to improve the heat dissipation performance of textiles to achieve a cooling effect when worn, a common practice in the prior art is to apply a functional coating with high thermal conductivity to the single-sided surface of the textile. This type of technical solution aims to utilize the high thermal conductivity of the coating to transfer heat from the human skin to the inner surface of the fabric, and to conduct rapid lateral conduction and diffusion on this surface to avoid heat accumulation in local areas of the skin. However, the fabric substrate that constitutes the main body of the fabric usually has a low thermal conductivity and a high thermal resistance. Therefore, even if the functional coating can efficiently diffuse heat laterally on the surface of the fabric, this heat still needs to penetrate the thickness of the entire fabric substrate to be transferred to the outer surface of the fabric and further dissipated into the external environment. Since the fabric substrate itself constitutes the main obstacle to the heat transfer path along the thickness direction, the longitudinal heat transfer efficiency from the inside to the outside of the fabric is low. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects or problems existing in the background technology and provide a gradient heat dissipation fabric, which can improve the heat dissipation efficiency of the fabric from the inside to the outside.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] Technical Solution 1: A gradient heat dissipation fabric, comprising: a fabric substrate having an inner surface facing the human skin and an outer surface facing away from the human skin when in use; a first functional layer, which is attached to at least a portion of the inner surface of the fabric substrate and is composed of a porous moisture-absorbing material; a second functional layer, which is attached to the outer surface of the fabric substrate and corresponds to at least a portion of the attachment area of ​​the first functional layer; the second functional layer comprises a plurality of heat-conducting components that are separated from each other and protrude relative to the outer surface of the fabric substrate, and a moisture-permeable layer is formed between each of the heat-conducting components to expose the fabric substrate. area; the thermally conductive component is composed of a polymer matrix and a thermally conductive filler filled in the polymer matrix, and is bonded and fixed to the fabric substrate through the polymer matrix; the thermal conductivity of the thermally conductive component is greater than the thermal conductivity of the fabric substrate; a third functional layer is a continuous film that conformally covers the thermally conductive component of the second functional layer and the fabric substrate located in the moisture-permeable area, the continuous film has a phase transition temperature between 28 degrees Celsius and 35 degrees Celsius, and the infrared emissivity of the continuous film below the phase transition temperature is lower than the infrared emissivity of the continuous film above the phase transition temperature.

[0006] Technical solution 2 based on technical solution 1: the thermally conductive filler of the thermally conductive component is hexagonal boron nitride sheet or graphene; the polymer matrix is ​​thermoplastic polyurethane or silicone rubber.

[0007] Technical Solution 3 based on Technical Solution 2: When the thermal conductive filler is a hexagonal boron nitride sheet, the hexagonal boron nitride sheet is a hexagonal boron nitride sheet surface-modified by a silane coupling agent, and the hexagonal boron nitride sheet is oriented in the polymer matrix along the planar direction of the fabric substrate.

[0008] Technical solution 4 based on technical solution 1: the plurality of heat-conducting components are distributed in a point-like or strip-like shape, and the protrusion height of the heat-conducting components relative to the outer surface of the fabric substrate is 50 microns to 500 microns.

[0009] Technical solution five based on technical solution one: the cross section of the heat-conducting component is a regular hexagon, and its side walls extend obliquely inward from bottom to top relative to the outer surface of the fabric substrate.

[0010] Technical solution six based on technical solution one: the material of the third functional layer is vanadium dioxide or tungsten-doped vanadium dioxide.

[0011] Technical Solution 7 based on Technical Solution 1 or 6: The infrared emissivity of the third functional layer is lower than 0.4 when the temperature is lower than the phase change temperature, and the infrared emissivity of the third functional layer is higher than 0.8 when the temperature is higher than the phase change temperature.

[0012] Technical solution eight based on technical solution one: the third functional layer is deposited on the carrier base film by vacuum sputtering and then composited with the second functional layer and the fabric substrate by thermal transfer.

[0013] Technical solution nine based on technical solution one: the porous hygroscopic material comprises a microencapsulated cooling agent and silica powder with a mesoporous structure.

[0014] Technical solution 10 based on technical solution 1: the first functional layer is arranged on the inner surface of the fabric substrate in a mutually separated dot pattern.

[0015] From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0016] Technical Solution 1 provides a gradient heat dissipation fabric. From the inside out, this fabric comprises a first functional layer, a fabric base material, a second functional layer, and a third functional layer. The first functional layer is made of a porous, moisture-absorbing material; the second functional layer includes a heat-conducting component and a moisture-permeable area; and the third functional layer is a continuous film with a transitional infrared emissivity attached to the outermost layer. The interaction of these multiple functional layers and the fabric base material improves the fabric's heat dissipation efficiency from the inside out.

[0017] Specifically, the first functional layer, a porous, hygroscopic material applied to the inner surface of the fabric substrate, leverages its porous structure and hygroscopic properties to rapidly absorb and disperse moisture generated by the human skin, while also providing an initial interface for subsequent heat transfer. This porous hygroscopic material, unlike conventional cooling coatings applied to the inside of fabric, utilizes its porous and sparse properties to rapidly absorb large amounts of heat and moisture dissipated by the human body within a short period of time. This layer then rapidly forms a heat and moisture gradient relative to the fabric substrate and the other functional layers on the outside, accelerating heat dissipation and air permeability.

[0018] Secondly, the second functional layer has discontinuously arranged heat-conducting components. The areas between the heat-conducting components form moisture-permeable areas that directly expose the fabric substrate, providing independent, parallel transmission paths for heat and moisture: heat is conducted by the heat-conducting components, while moisture is transmitted through the exposed areas of the fabric substrate. This improves the conflict between heat dissipation and moisture permeability in the second functional layer. Furthermore, the areas of the second functional layer and the first functional layer are aligned on opposite sides of the fabric substrate, establishing a preferential heat transfer path. When heat reaches the inner first functional layer, it is actively and directionally guided by the structure, penetrating the fabric substrate itself and efficiently transferred to the corresponding heat-conducting components on the outer side. Furthermore, due to the high heat gradient formed on the inner and outer sides of the fabric substrate, the obstruction of the fabric substrate itself is minimized.

[0019] On this basis, the thermally conductive component is composed of a polymer matrix and a thermally conductive filler. The introduction of the polymer matrix provides excellent adhesive properties, enabling the entire thermally conductive component to be firmly fixed to the flexible fabric substrate, ensuring the durability and washability of the fabric. At the same time, the polymer matrix gives the thermally conductive component the necessary flexibility, allowing it to stretch and bend with the fabric substrate, thereby ensuring the wearing comfort of the final product and avoiding the stiffness caused by hard materials. The thermally conductive filler with a high thermal conductivity coefficient makes the thermally conductive component as a whole have a thermal conductivity far higher than that of the fabric substrate, allowing heat to preferentially pass through the thermally conductive component, which is a low thermal resistance channel. In addition, the structure of the thermally conductive component allows the second functional layer to easily form a raised structure protruding from the outer surface of the fabric substrate. This raised structure is not a simple, conventional morphological design, but is the key to achieving efficient heat dissipation. In this technical solution, the third functional layer is defined as conformally covering the exposed thermal conductive component and moisture-permeable area of ​​the fabric substrate of the first functional layer. Due to the raised structure of the thermally conductive component, the effective area of ​​the third functional layer is further increased, and the thermal radiation power of an object is proportional to its surface area. The raised three-dimensional structure allows the actual surface area of ​​the third functional layer, responsible for radiative heat dissipation, to be much larger than the two-dimensional projected area of ​​the fabric, significantly increasing its total heat radiation flux. Furthermore, microscopic air convection channels are formed between the raised structure and the surrounding moisture-permeable areas. When the human body moves, these channels help to remove some heat, further enhancing the heat dissipation effect.

[0020] This structure, combined with the third functional layer's own temperature-sensitive infrared emissivity jump characteristics, further improves the fabric's heat dissipation efficiency. When the thermally conductive component transfers heat to the outer surface and causes the temperature of the third functional layer to rise above its phase transition temperature, the film's infrared emissivity undergoes a dramatic jump from small to large. At this point, thanks to the huge surface area provided by the raised structure, the third functional layer can actively and powerfully dissipate heat to the external environment with extremely high efficiency through a combination of far-infrared radiation and microscopic convection. This efficient heat dissipation behavior will keep the outer surface temperature at a relatively low level, thereby artificially establishing and maintaining a significant temperature gradient between the inner and outer sides of the fabric substrate, providing the driving force for heat to flow from the inside to the outside.

[0021] Therefore, the overall beneficial effect of this solution is achieved through the mutual coordination and joint action of various technical features. It points to the main technical goal of heat dissipation and moisture permeability, and through the mutual cooperation of various functional layers, the heat dissipation efficiency of the fabric is greatly improved.

[0022] In Technical Solution 2, by specifically limiting the thermally conductive filler to hexagonal boron nitride sheets or graphene, and the polymer matrix to thermoplastic polyurethane or silicone rubber, the efficient thermal conductivity of the thermally conductive component and its strong adhesion to the fabric substrate are further guaranteed. Hexagonal boron nitride sheets and graphene are currently known to have extremely high in-plane thermal conductivity. As thermally conductive fillers, they can maximize the thermal conductivity coefficient of the thermally conductive component. Thermoplastic polyurethane and silicone rubber are two polymer materials with excellent flexibility, elasticity, and weather resistance. As matrices, they can give the final product excellent wearing comfort and physical durability while ensuring strong adhesion to the fabric substrate.

[0023] In technical solution three, the state of the hexagonal boron nitride flakes is further defined. First, the surface of the hexagonal boron nitride flakes is modified by a silane coupling agent, and the technical effect is that a stable chemical bond is formed between the thermally conductive filler and the polymer matrix. This bonding reduces the phonon scattering at the interface between the two, thereby significantly reducing the interfacial thermal resistance and improving the overall thermal conductivity of the composite material. Secondly, by limiting the orientation of the hexagonal boron nitride flakes in the polymer matrix along the plane direction of the fabric substrate, the anisotropic physical property of the material that the thermal conductivity coefficient in the plane is much higher than that in the vertical direction is fully utilized. This orientation arrangement enables heat to be conducted and diffused extremely quickly within the plane of the thermally conductive component, ensuring that the heat can be quickly dispersed from the penetration point to the surface of the entire thermally conductive component, providing a basis for the overall and uniform heat dissipation of the third functional layer.

[0024] Technical Solution 4 specifically defines the geometric shape of the heat-conducting components as either dot-shaped or strip-shaped, with the protrusion height limited to between 50 and 500 microns. Dot-shaped and strip-shaped patterns are both easily implemented in engineering and can effectively form a discontinuous heat-conducting network. The height range of 50 to 500 microns is an optimized balance between ensuring a sufficiently large heat dissipation surface area and maintaining the softness of the fabric. Below 50 microns, the effect of increasing surface area and forming air convection channels is not significant; above 500 microns, the fabric's feel and drape may be affected.

[0025] In Technical Solution 5, the heat-conducting component is defined as having a regular hexagonal cross-section, with its sidewalls extending inwardly from bottom to top relative to the outer surface of the fabric substrate. By defining the heat-conducting component's cross-section as a regular hexagon, the maximum permeable area can be enclosed with the least amount of heat-conducting material (i.e., the wall length of the heat-conducting component) while ensuring a sufficiently large permeable area, thereby optimizing material utilization efficiency and structural stability. Furthermore, the heat-conducting component's inclined sidewalls are not simply a change in shape; rather, they utilize the principles of fluid mechanics to significantly enhance convective heat transfer efficiency. When air flows over the outer surface of the fabric, this inclined sidewall structure actively guides the airflow and generates micro-eddies within and around it. According to the principles of fluid mechanics, these micro-eddies can effectively disrupt and thin the still air boundary layer with high thermal resistance that clings to the fabric surface. The disruption of this boundary layer allows heat to be more easily carried away by the flowing air through convection from the sidewall surface of the heat-conducting component and the exposed surface of the fabric substrate. Therefore, the shape of the heat-conducting component and its inclined sidewalls can effectively improve the fabric's heat dissipation capacity.

[0026] Technical Solution 6 specifies that the material for the third functional layer be vanadium dioxide or tungsten-doped vanadium dioxide. Vanadium dioxide is a known material that undergoes a semiconductor-to-metal phase transition at a specific temperature, accompanied by a dramatic change in optical properties. Tungsten doping is a technical means of effectively controlling its phase transition temperature to a comfortable range for the human body. This solution ensures the feasibility of the third functional layer's intelligent temperature control function.

[0027] Technical Solution 7 specifically limits the infrared emissivity of the third functional layer to less than 0.4 below the phase transition temperature and greater than 0.8 above the phase transition temperature. A low emissivity below 0.4 ensures effective thermal insulation at low temperatures, while a high emissivity above 0.8 ensures strong radiative heat dissipation at high temperatures. This difference in emissivity exceeding 0.4 ensures that the third functional layer can produce significant heat dissipation and maintain an effective temperature gradient for the entire system.

[0028] In Technical Solution 8, the formation method of the third functional layer is specifically defined as first vacuum sputtering deposition on the carrier base film, and then compounding it on the fabric through thermal transfer. The vacuum and high temperature conditions required for the preparation of high-quality vanadium dioxide and other thin films are incompatible with the characteristics of textiles themselves that are not resistant to high temperatures and are prone to outgassing in a vacuum. This solution decouples the two steps of film preparation and fabric compounding, so that the film can be prepared on a large scale and at low cost under ideal conditions (on a high-temperature resistant carrier base film), and then applied to the fabric through a mature and safe thermal transfer process. This approach ensures high performance and high yield of the final product, and is the key to the industrial production of this technology.

[0029] In Technical Solution 9, the porous hygroscopic material of the first functional layer is specifically defined as comprising a microencapsulated cooling agent and a silica powder with a mesoporous structure. The microencapsulated cooling agent can provide a physiological and long-lasting cooling experience by slowly releasing its contents. The silica powder with a mesoporous structure, due to its huge specific surface area, can extremely quickly absorb instantaneous heat and moisture from the skin surface. The combination of these two materials enables the first functional layer to not only manage moisture but also provide a dual physical and physiological cooling effect in the initial stage of heat transfer.

[0030] Technical Solution 10 specifically defines the attachment method for the first functional layer as a discrete dot pattern. This ensures that the first functional layer effectively covers the body's high-heat areas while preserving the fabric substrate's areas of direct contact with the skin to the greatest extent possible. These uncovered areas maintain the fabric's inherent breathability and skin-friendliness, avoiding the dampness that can result from full coverage, thus achieving a better balance between functionality and wearing comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 Schematic cross-sectional view of a gradient heat dissipation fabric according to an embodiment of the present invention;

[0033] Figure 2 This is a front schematic diagram of a gradient heat dissipation fabric according to an embodiment of the present invention.

[0034] Description of main reference numerals:

[0035] Fabric substrate 10;

[0036] a first functional layer 20;

[0037] Second functional layer 30; heat conducting component 31; moisture permeable area 32; side wall 33;

[0038] The third functional layer 40 . DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are preferred embodiments of the present invention and should not be regarded as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] In the claims, description and drawings of the present invention, unless otherwise clearly defined, the use of terms such as "first", "second" or "third" is for the purpose of distinguishing different objects rather than for describing a specific order.

[0041] In the claims, specification and the above-mentioned drawings of the present invention, unless otherwise expressly defined, directional words such as the terms "center", "transverse", "longitudinal", "horizontal", "vertical", "top", "bottom", "inside", "outside", "up", "down", "front", "back", "left", "right", "clockwise", "counterclockwise" and the like indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the specific scope of protection of the present invention.

[0042] In the claims, description and above-mentioned drawings of the present invention, unless otherwise expressly defined, the terms "fixed connection" or "fixed connection" should be understood in a broad sense, that is, any connection method without displacement relationship and relative rotation relationship between the two parties, that is, including non-detachable fixed connection, detachable fixed connection, integral connection and fixed connection through other devices or elements.

[0043] In the claims, description and drawings of the present invention, if the terms "include", "have" and their variations are used, they are intended to mean "including but not limited to".

[0044] Example

[0045] The embodiment of the present invention relates to a gradient heat dissipation fabric, referring to Figure 1, which comprises: a fabric substrate 10, which has an inner surface facing human skin and an outer surface away from human skin when in use; a first functional layer 20, which is attached to at least a portion of the inner surface of the fabric substrate 10 and is composed of a porous moisture-absorbing material; a second functional layer 30, which is attached to the outer surface of the fabric substrate 10 and corresponds to at least a portion of the attachment area of ​​the first functional layer 20; the second functional layer 30 includes a plurality of heat-conducting components 31 that are separated from each other and protrude relative to the outer surface of the fabric substrate 10, and a moisture-permeable area 32 that exposes the fabric substrate 10 is formed between each of the heat-conducting components 31; The thermally conductive component 31 is composed of a polymer matrix and a thermally conductive filler filled in the polymer matrix, and is bonded and fixed to the fabric substrate 10 through the polymer matrix; the thermal conductivity of the thermally conductive component 31 is greater than the thermal conductivity of the fabric substrate 10; the third functional layer 40 is a continuous film that conformally covers the thermally conductive component 31 of the second functional layer 30 and the fabric substrate 10 located in the moisture-permeable area 32, the continuous film has a phase transition temperature between 28 degrees Celsius and 35 degrees Celsius, and the infrared emissivity of the continuous film below the phase transition temperature is lower than its infrared emissivity above the phase transition temperature.

[0046] Reference Figure 1 As shown in the cross-sectional structure, the gradient heat dissipation fabric of the present invention is centered around a fabric substrate 10. Fabric substrate 10 forms the foundation of the fabric body and is divided into two surfaces: an inner surface facing the skin when worn, and an outer surface facing away from the skin and toward the external environment. Fabric substrate 10 can be made of, but is not limited to, polyester, polyamide, cotton, viscose, or blends of at least two of these fibers. Its structure can be either knitted or woven to meet the elasticity, drape, and strength requirements of different garments.

[0047] The first functional layer 20 is provided on the inner surface of the fabric substrate 10. The first functional layer 20 may cover the entire area of ​​the inner surface of the fabric substrate 10, or may only cover a part of a preset area, such as the position corresponding to the high-temperature sweating area of ​​the human body. The first functional layer 20 is made of a porous hygroscopic material. "Porous" here means that the material layer has a microscopically interconnected or closed pore structure to increase its specific surface area. "Hygroscopic" means that the material can absorb and store a certain amount of water. In one embodiment, the porous hygroscopic material can be formed by mixing one or more functional powders with a polymer binder to form a slurry, and then applying it to the inner surface of the fabric substrate 10 by screen printing, coating or spraying. The functional powder can be silica with a mesoporous structure, porous zeolite or activated carbon; the polymer binder can be a water-based polyurethane, an acrylic emulsion or a silicone resin.

[0048] The second functional layer 30 is disposed on the outer surface of the fabric substrate 10. The area where the second functional layer 30 is disposed corresponds spatially to the area where the first functional layer 20 is attached to the inner surface. This means that, viewed perpendicular to the fabric plane, the second functional layer 30 and the first functional layer 20 overlap in projection at least partially. This correspondence can be achieved by performing alignment processing on both sides of the fabric.

[0049] The structure of the second functional layer 30 is discontinuous and is composed of a plurality of mutually separated heat conducting components 31. Figure 2 In the top view of the structure shown, gaps exist between the thermally conductive components 31. Within these gaps, the outer surface of the fabric substrate 10 is directly exposed. These exposed areas constitute the moisture-permeable regions 32. The geometric shape of the thermally conductive components 31 can be dotted, striped, grid-like, or other discontinuous patterns. In three dimensions, these thermally conductive components 31 protrude relative to the outer surface of the fabric substrate 10, forming a three-dimensional structure with a certain height. The thermally conductive components 31 are composed of a composite material comprising a polymer matrix and a thermally conductive filler. The polymer matrix serves as a continuous phase, bonding the thermally conductive filler particles together and firmly adhering the entire thermally conductive component 31 to the outer surface of the fabric substrate 10. The polymer matrix material selection must balance adhesion to the fabric substrate 10 and its own flexibility. For example, it can be thermoplastic polyurethane, liquid silicone rubber, or epoxy resin. The thermally conductive filler acts as a dispersed phase, with its own thermal conductivity much higher than that of the polymer matrix. By forming a thermally conductive network within the polymer matrix, it significantly improves the thermal conductivity of the entire thermally conductive component 31. The thermally conductive filler can be made of metal powder, such as silver powder or copper powder, ceramic powder, such as aluminum nitride, aluminum oxide, or boron nitride, or carbon materials, such as graphene or carbon nanotubes. The selection and proportioning of the materials must ensure that the overall thermal conductivity of the resulting thermally conductive component 31 is greater than that of the fabric substrate 10 used as a reference.

[0050] The third functional layer 40 is the outermost layer of the composite structure. It is a continuous, non-porous film. It conformally covers the surface of the second functional layer 30 in three dimensions, meaning it follows the topography of the second functional layer 30. It covers both the top and sidewalls 33 of the raised heat-conducting components 31, as well as the surface of the fabric substrate 10 in the moisture-permeable area 32. This third functional layer 40 exhibits unique temperature-sensitive physical properties. It has a phase transition temperature between 28°C and 35°C. When the film's actual temperature is below this phase transition temperature, its surface infrared emissivity (first infrared emissivity) remains low. When its temperature rises above this phase transition temperature due to heat absorption, its infrared emissivity (second infrared emissivity) undergoes a sudden change, reaching a level significantly higher than the first infrared emissivity. This reversible change in infrared emissivity with temperature is the physical basis for this layer's intelligent thermal radiation regulation. The material system capable of achieving this function may include, but is not limited to, certain specific metal oxides, liquid crystal materials, or high molecular polymers.

[0051] The thermally conductive filler of the thermally conductive component 31 is hexagonal boron nitride flakes or graphene, and the polymer matrix is ​​thermoplastic polyurethane or silicone rubber. Specifically, in a preferred embodiment, the thermally conductive filler is a highly crystalline hexagonal boron nitride flake with a flake diameter of 5 to 15 microns and a thickness of 50 to 200 nanometers. The polymer matrix is ​​an addition-type two-component liquid silicone rubber. The hexagonal boron nitride flakes are mixed with component A of the liquid silicone rubber at a volume filling rate of 20% to 60%. In another embodiment, the thermally conductive filler can be a high-quality graphene powder with a small number of layers, and the polymer matrix can be a polyether or polyester thermoplastic polyurethane particle. The graphene powder and thermoplastic polyurethane particles are melt-blended in a twin-screw extruder to prepare a thermally conductive composite masterbatch for subsequent processing.

[0052] Furthermore, when the thermally conductive filler is a hexagonal boron nitride sheet, the hexagonal boron nitride sheet is a hexagonal boron nitride sheet that has been surface-modified with a silane coupling agent, and the hexagonal boron nitride sheet is oriented in the polymer matrix along the plane direction of the fabric substrate 10. Specifically, the surface modification treatment is carried out in a reactor containing a mixed solution of ethanol and water. Hexagonal boron nitride sheet powder is added to the solution, and a silane coupling agent, such as γ-methacryloxypropyltrimethoxysilane (KH-570), is added at a weight percent of the powder. The reaction is mechanically stirred at a temperature of 60 to 80 degrees Celsius for 2 to 4 hours, allowing the silane coupling agent molecules to hydrolyze and chemically bond with the hydroxyl groups on the surface of the hexagonal boron nitride sheet. After the reaction is completed, the powder is centrifuged, washed, filtered, and dried to obtain modified hexagonal boron nitride sheets with organic functional groups grafted onto the surface. When the polymer slurry containing the modified powder is subsequently applied to the fabric substrate 10, the shear force generated during the application process will induce these layers with a high aspect ratio to tend to be arranged in a direction parallel to the shear force, that is, along the planar direction of the fabric substrate 10.

[0053] The plurality of thermally conductive components 31 are distributed in a dot or strip pattern, and the height of the thermally conductive components 31 raised relative to the outer surface of the fabric substrate 10 is 50 to 500 microns. Specifically, when the thermally conductive components 31 are distributed in a dot or strip pattern, they are typically formed and affixed to the fabric substrate 10 via a process such as screen printing or dispensing. In one embodiment, a slurry composed of liquid silicone rubber and thermally conductive filler is printed on the outer surface of the fabric substrate 10 using thick-plate screen printing technology. The screen pattern is the desired dot or strip pattern, and the thickness of the screen determines the height of the raised thermally conductive components 31. After printing, the polymer matrix is ​​cross-linked and cured by heating, thereby physically entangled and chemically bonded with the fibers of the fabric substrate 10, achieving a secure fixation. The diameter of the dots in the dot pattern can be set to 1 to 3 mm, and the center-to-center distance between adjacent dots can be set to 2 to 6 mm. The line width of the strip pattern can be set to 0.5 to 1.5 mm. The protrusion height of the heat conducting member 31 is preferably 100 to 300 micrometers.

[0054] In this embodiment, refer to Figure 1 and Figure 2The cross section of the heat-conducting component 31 is a regular hexagon, and its side wall 33 extends inwardly from bottom to top relative to the outer surface of the fabric substrate 10. Specifically, the structure with a specific three-dimensional morphology can be prepared and fixed on the fabric substrate 10 by precise mold forming or additive manufacturing process. In one embodiment, a metal or silicone mold with a hexagonal honeycomb groove is first prepared by laser engraving or photolithography, wherein the side wall 33 of the groove has a preset inclination angle. Then, a composite material composed of thermoplastic polyurethane and heat-conducting filler is filled into the mold, and then the fabric substrate 10 is covered thereon. The molten polymer matrix is ​​infiltrated into the fabric fiber and bonded by hot pressing. After cooling and demolding, the desired heat-conducting component 31 is formed on the fabric substrate 10. The diameter of the inscribed circle of the hexagonal hole can be set to 1 to 2 mm, and the wall thickness of the heat-conducting component 31 can be set to 0.1 to 0.3 mm. The inclination angle of the side wall 33, that is, the angle between the surface of the side wall 33 and the normal direction of the plane of the fabric substrate 10, is preferably 15 to 30 degrees, for example, 22 degrees.

[0055] In addition, the material of the third functional layer 40 is vanadium dioxide or tungsten-doped vanadium dioxide. Specifically, in a preferred embodiment, tungsten-doped vanadium dioxide is selected as the core material. By co-sputtering a high-purity vanadium target and a high-purity tungsten target during the sputtering process and precisely controlling the power ratio between the two, the atomic doping concentration of tungsten in the final film can be controlled within a range of 1.5 to 1.7 atomic percent (at%), for example, 1.6±0.1at%. This specific concentration of doping can effectively reduce the phase transition temperature of vanadium dioxide from approximately 68 degrees Celsius to a temperature range comfortable for the human body.

[0056] In addition, the infrared emissivity of the third functional layer 40 is lower than 0.4 when it is below the phase transition temperature, and its infrared emissivity is higher than 0.8 when it is above the phase transition temperature. Specifically, this physical property is the result of the combined effect of the inherent properties of the material and the preparation process. By optimizing the sputtering process parameters, such as background vacuum, working pressure, oxygen partial pressure, substrate temperature and subsequent annealing process, it can be ensured that the deposited tungsten-doped vanadium dioxide film has good crystalline quality and stoichiometric ratio. In a preferred embodiment, its average infrared emissivity in the 8 to 14 micron band is about 0.3 at 25 degrees Celsius (below the phase transition temperature). When the temperature rises to 40 degrees Celsius (above the phase transition temperature), its average infrared emissivity jumps to about 0.85. This emissivity difference of more than 0.5 is a performance guarantee for achieving efficient and intelligent heat radiation regulation.

[0057] Furthermore, the third functional layer 40 is deposited on a carrier base film by vacuum sputtering and then thermally transferred to the second functional layer 30 and the fabric substrate 10. Specifically, this process begins with selecting a high-temperature-resistant, flat, and vacuum-compatible flexible carrier base film, such as a 50-100 micron thick polyimide (PI) film or a surface-treated PET film. This carrier base film is placed in the vacuum chamber of a magnetron sputtering apparatus, and a tungsten-doped vanadium dioxide thin film of a predetermined thickness is deposited on its surface via reactive magnetron co-sputtering. After deposition, a "heat transfer film" with a functional thin film is obtained. This heat transfer film is then aligned with the outer surface of the fabric substrate 10, where the first and second functional layers 30 have been deposited. Using a flatbed or roller-type hot press, the film is hot-pressed for 10-20 seconds at a temperature of 140-160 degrees Celsius and a pressure of 2-4 kg / cm². After cooling, the carrier base film is removed, and the functional thin film layer is securely transferred and laminated to the outermost surface of the fabric.

[0058] In addition, the porous hygroscopic material comprises a microencapsulated cooling agent and a silica powder having a mesoporous structure. Specifically, in a preferred embodiment, the cooling agent is L-menthol or menthol, and is prepared into microcapsules by interfacial polymerization or complex coacervation. The average particle size of the microcapsules is 5 to 15 microns, and the drug loading of the cooling agent is 20% to 40% (weight percentage). The silica powder having a mesoporous structure has a spherical morphology, an average particle size of 1 to 5 microns, and a specific surface area of ​​greater than 300 square meters / gram. The two powders are mixed with an aqueous polyurethane adhesive to prepare a slurry, wherein the amount of microcapsules added is 10% to 20% of the total solid content of the slurry, and the amount of silica powder added is 10% to 25%.

[0059] Furthermore, the first functional layer 20 is arranged on the inner surface of the fabric substrate 10 in a mutually separated dot pattern. Specifically, the dot pattern can be formed by a screen printing process. A 150 to 200 mesh screen is selected to produce a pattern consisting of circular or square dots. The diameter or side length of the dots can be set to 2 to 5 mm, and the spacing between dots can be set to 2 to 5 mm. This non-continuous pattern design can ensure that the functional area effectively covers the high-temperature area of ​​the human body while retaining more than 50% of the original surface of the fabric substrate 10 in direct contact with the skin, thereby providing moisture absorption and cooling functions while maximizing the original breathability and skin-friendliness of the fabric.

[0060] This embodiment relates to a gradient heat dissipation fabric. From the inside out, the fabric comprises, in order: a first functional layer 20, a fabric substrate 10, a second functional layer 30, and a third functional layer 40. The first functional layer 20 is made of a porous, moisture-absorbing material; the second functional layer 30 includes a heat-conducting component 31 and a moisture-permeable region 32; and the third functional layer 40 is a continuous, outermost film with a transitional infrared emissivity. The interaction of these multiple functional layers and the fabric substrate 10 improves the fabric's heat dissipation efficiency from the inside out.

[0061] The above description and embodiments are intended to explain the scope of protection of the present invention, but do not constitute a limitation thereto. Modifications, equivalent substitutions, or other improvements to the embodiments of the present invention or portions thereof that can be obtained by a person of ordinary skill in the art through logical analysis, reasoning, or limited experimentation based on the teachings of the present invention or the above embodiments, combined with common knowledge, ordinary technical knowledge in the field, and / or prior art, should all be included within the scope of protection of the present invention.

Claims

1. A gradient heat dissipation fabric, characterized in that: include: A fabric substrate (10) having an inner surface facing toward human skin and an outer surface facing away from human skin when in use; a first functional layer (20), which is attached to at least a portion of the inner surface of the fabric substrate (10) and is composed of a porous moisture-absorbing material; a second functional layer (30) attached to the outer surface of the fabric substrate (10) and corresponding to at least a portion of the attachment area of ​​the first functional layer (20); the second functional layer (30) comprises a plurality of heat-conducting components (31) separated from each other and protruding relative to the outer surface of the fabric substrate (10), and a moisture-permeable area (32) exposed to the fabric substrate (10) is formed between each of the heat-conducting components (31); the heat-conducting components (31) are composed of a polymer matrix and a heat-conducting filler filled in the polymer matrix, and are bonded and fixed to the fabric substrate (10) by the polymer matrix; The thermal conductivity of the heat-conducting component (31) is greater than the thermal conductivity of the fabric substrate (10); The third functional layer (40) is a continuous film that conformally covers the heat-conducting component (31) of the second functional layer (30) and the fabric substrate (10) located in the moisture-permeable area (32), the continuous film having a phase transition temperature between 28 degrees Celsius and 35 degrees Celsius, and the infrared emissivity of the continuous film below the phase transition temperature is lower than the infrared emissivity above the phase transition temperature.

2. The gradient heat dissipation fabric according to claim 1, characterized in that: The heat-conducting filler of the heat-conducting component (31) is hexagonal boron nitride sheets or graphene; and the polymer matrix is ​​thermoplastic polyurethane or silicone rubber.

3. A gradient heat dissipation fabric as claimed in claim 2, characterized in that when When the thermal conductive filler is a hexagonal boron nitride sheet, the hexagonal boron nitride sheet is a hexagonal boron nitride sheet surface-modified by a silane coupling agent, and the hexagonal boron nitride sheet is oriented in the polymer matrix along the plane direction of the fabric substrate (10).

4. The gradient heat dissipation fabric according to claim 1, characterized in that: The plurality of heat-conducting components (31) are distributed in a dot-like or strip-like manner, and the protrusion height of the heat-conducting components (31) relative to the outer surface of the fabric substrate (10) is 50 micrometers to 500 micrometers.

5. The gradient heat dissipation fabric according to claim 1, characterized in that: The cross section of the heat-conducting component (31) is a regular hexagon, and its side wall (33) extends inwardly from bottom to top relative to the outer surface of the fabric substrate (10).

6. The gradient heat dissipation fabric according to claim 1, characterized in that: The material of the third functional layer (40) is vanadium dioxide or tungsten-doped vanadium dioxide.

7. A gradient heat dissipation fabric according to claim 1 or 6, characterized in that: The infrared emissivity of the third functional layer (40) is lower than 0.4 when the temperature is lower than the phase transition temperature, and is higher than 0.8 when the temperature is higher than the phase transition temperature.

8. The gradient heat dissipation fabric according to claim 6, characterized in that: The third functional layer (40) is deposited on a carrier base film by vacuum sputtering and then composited with the second functional layer (30) and the fabric substrate (10) by thermal transfer.

9. The gradient heat dissipation fabric according to claim 1, characterized in that: The porous hygroscopic material comprises a microencapsulated cooling agent and silicon dioxide powder with a mesoporous structure.

10. The gradient heat dissipation fabric according to claim 1, characterized in that: The first functional layer (20) is arranged on the inner surface of the fabric substrate (10) in a mutually separated dot matrix pattern.

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