Heating thermal fabric and preparation method thereof

Abstract

The invention discloses a heating warm-keeping fabric and a preparation method thereof.The preparation method comprises the following steps that first functional filaments are prepared, the first functional filaments are interwoven to prepare a light-absorbing heating layer, and the fabric tightness of the light-absorbing heating layer is 40%-60%; preparing a composite layer on the bottom surface of the light-absorbing heating layer, wherein the composite layer comprises a heat conduction layer; a phase change layer and a thermal switch layer are prepared, the phase change layer and the thermal switch layer are sequentially connected with the light absorption heating layer, and the phase change layer is located between the heat conduction layer and the thermal switch layer; preparing second functional filaments, spinning the second functional filaments and modal fibers to obtain composite yarns, and interweaving the composite yarns to obtain a heat storage layer; the top face of the heat storage layer is connected with the bottom face of the heat switch layer, and the heating and warm keeping fabric is obtained. The heating and warm-keeping fabric can actively absorb light and emit heat, heat is unidirectionally conducted to the heat storage layer from the heat absorption side and stored by the heat storage layer, and the warm-keeping effect of the fabric can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the field of textile technology, and particularly relates to a heat-generating and warm-keeping fabric and a preparation method thereof. Background Art

[0002] In the field of functional textile materials, the research on thermal insulation fabrics continues to receive the focus of academia and industry. The current mainstream thermal insulation technology mainly relies on increasing the static air content between fibers to improve thermal resistance, such as using thickened filling layers or fluffy structures. However, this physical thickening strategy will inevitably lead to the expansion of the fabric volume and a significant increase in gram weight, which not only limits the fashion and flexibility of clothing design, but also causes a sense of pressure and inconvenience when wearing. For example, the Chinese utility model patent with the announcement number CN220785113U and the patent name "A wool knitted multi-layer thermal storage fabric" discloses the use of a high-count and high-density wool knitted layer. Although the thickness of the fabric is reduced by increasing the yarn fineness, its warmth retention still relies on the inherent limited heat storage capacity of wool itself, and fails to break through the equilibrium bottleneck of material thermodynamics.

[0003] Another example is the active heating technology developed in recent years, which attempts to use photothermal and electrothermal mechanisms to increase heat input. For example, the Chinese utility model patent with announcement number CN220300978U and patent name "A Far-Infrared Self-Heating Thermal Storage Fabric" discloses that the fabric uses warp and weft yarns to form a three-layer structure, combined with far-infrared heating yarns and spandex yarns to improve the warmth and comfort of the fabric. However, the heat retention and transfer capabilities during the heating process are not improved. This type of design has key defects in the heat transfer path: on the one hand, the heat energy generated by the heating unit is easily dissipated to the low-temperature environment through radiation, convection, etc.; on the other hand, there is a lack of active control over the direction of heat flow, resulting in the inability to efficiently accumulate heat on the surface in contact with the human body.

[0004] In essence, existing technologies have not yet solved the problem of coordinated optimization of "heat gain efficiency" (input energy accumulation rate) and "thermal management efficiency" (heat directional conduction and retention capabilities). Summary of the Invention

[0005] In view of this, in order to overcome the defects of the prior art, the object of the present invention is to provide a heat-generating and warm-keeping fabric and a preparation method thereof.

[0006] An object of the present invention is to provide a method for preparing a heat-generating and thermal-insulating fabric, comprising the following steps:

[0007] preparing first functional filaments, and weaving the first functional filaments to prepare a light-absorbing and heat-generating layer, wherein the fabric tightness of the light-absorbing and heat-generating layer is 40%-60%;

[0008] Prepare a composite layer on the bottom surface of the light-absorbing and heat-generating layer, wherein the composite layer includes a heat-conducting layer;

[0009] Prepare a phase change layer and a heat switch layer, and sequentially connect the phase change layer and the heat switch layer to the light-absorbing and heat-generating layer, wherein the phase change layer is located between the heat conduction layer and the heat switch layer;

[0010] preparing a second functional filament, spinning the second functional filament and modal fiber to obtain a composite yarn, and then interweaving the composite yarn to obtain a heat storage layer;

[0011] The top surface of the heat storage layer is connected to the bottom surface of the heat switch layer to obtain the heat-generating and warm-keeping fabric.

[0012] By introducing light-absorbing materials into the yarn to make the surface layer of the fabric, the surface layer is designed at the molecular scale to give it the ability to selectively absorb the solar spectrum (especially visible light and near-infrared light), thereby improving the efficiency of heat input from the energy source; innovatively, a composite layer, a phase change layer, and a heat switch layer are prepared between the surface layer and the bottom layer of the fabric to establish a directional heat flow driving mechanism from the light-receiving surface to the warm-keeping surface, thereby minimizing the reverse dissipation of heat; finally, the bottom layer is made of a composite yarn made of a second functional filament prepared from modified heat storage powder and polyester particles and skin-friendly modal fiber, which can maintain the heat storage density of the fabric while maintaining wearing comfort. The present invention synergistically breaks through the energy efficiency bottleneck of traditional thermal insulation fabrics from the above three aspects, and can significantly improve the thermal insulation rate of the fabric.

[0013] According to some preferred embodiments of the present invention, the first functional filament is prepared by the following method:

[0014] 1,6-hexamethylenediamine, sebacic acid chloride and light-absorbing material are uniformly mixed and polymerized to obtain a modified polyamide melt, and the modified polyamide melt is spun to obtain the first functional filament, wherein the solar light absorption rate of the first functional filament is greater than or equal to 92%.

[0015] According to some preferred embodiments of the present invention, the mass ratio of 1,6-hexamethylenediamine to sebacic acid chloride is 5-9:1-3, and the mass proportion of the light-absorbing material relative to 1,6-hexamethylenediamine is 3%-10%.

[0016] According to some preferred embodiments of the present invention, the light-absorbing material is carboxylated graphene quantum dots.

[0017] Specifically, the polymerization reaction is a gradient polymerization reaction, and the specific method of the polymerization reaction is: 1,6-hexamethylenediamine, sebacic acid chloride and light-absorbing material are premixed at 50-60°C for 20-30 minutes, then pre-condensed at 170-190°C for 1-2 hours, and finally reduced-compression polymerization is carried out at 230-250°C for 2-3 hours.

[0018] Since the light-absorbing and heat-generating layer of the fabric is woven from first-functional filaments, the intersection of yarns, the gaps between yarns, and the texture of the fabric can cause light to be reflected and refracted on the surface and inside of the light-absorbing and heat-generating layer, enabling the light-absorbing material to better absorb light and generate heat.

[0019] According to some preferred embodiments of the present invention, the composite layer further includes a metal layer, and the method for preparing the composite layer on the bottom surface of the light-absorbing and heat-generating layer is:

[0020] First, a metal layer is sputtered on the bottom surface of the light-absorbing and heat-generating layer. A heat-conducting material is selected and surface-treated before preparing a dispersion. The light-absorbing and heat-generating layer with the metal layer sputtered on the bottom surface is used as the working electrode and immersed in an electrolytic bath filled with the dispersion for deposition. The heat-conducting material is deposited on the surface of the metal layer to form a heat-conducting layer. The thickness of the heat-conducting layer is 5-20 μm.

[0021] Preferably, in the step of preparing the dispersion, the surface-treated thermal conductive material is first uniformly dispersed in deionized water or an organic solvent using an ultrasonic disruptor, and an appropriate amount of a first dispersant (such as SDS, SDBS) is added to the system to form a stable, charged colloidal dispersion.

[0022] In some embodiments of the present invention, the thickness of the light-absorbing and heat-generating layer is 0.2-0.5 mm.

[0023] According to some preferred implementation aspects of the present invention, the thickness of the metal layer is 1-3 nm, and the material of the metal layer is gold or platinum.

[0024] According to some preferred embodiments of the present invention, the thermally conductive material is carbon nanotubes. The addition of a thermally conductive material can improve the thermal conductivity of the fabric. Carbon nanotubes are selected as the thermally conductive material because they have extremely high axial thermal conductivity and elastic modulus, effectively transferring heat along the axial direction of the carbon nanotubes, thereby improving thermal conductivity.

[0025] According to some preferred embodiments of the present invention, the method for surface treating the heat conductive material comprises: performing a carboxylation or amino treatment on the heat conductive material. Surface treatment of the heat conductive material imparts a stable charge to the material in water or a specific solvent (e.g., ethanol or DMF). During deposition, the electric field forces drive the negatively charged carboxylated carbon nanotubes toward the anode or the positively charged amino carbon nanotubes toward the cathode. The electric field lines perpendicular to the working electrode surface guide the carbon nanotubes to align and distribute perpendicular to the plane of the metal layer. Controlling the concentration of the dispersion further controls the carbon nanotube content to achieve an appropriate carbon nanotube distribution density. Controlling the deposition time controls the thickness and density of the deposited heat conductive layer. After deposition, the working electrode is removed and thoroughly rinsed with deionized water to remove residual electrolyte and the first dispersant. Optionally, to enhance the bonding between the heat conductive layer and the metal layer, the heat conductive layer and the composite layer may be heat treated at a temperature tolerable by the light-absorbing and heat-generating layer (e.g., 120-200°C).

[0026] According to some preferred embodiments of the present invention, the method for preparing a phase change layer and a thermal switch layer, and sequentially connecting the phase change layer and the thermal switch layer to the light-absorbing and heat-generating layer is:

[0027] First, a phase change material is selected and microencapsulated, and then uniformly dispersed in a matrix, and then cured at a low temperature (lower than the phase change temperature) to obtain the phase change layer; the matrix is ​​an addition-type silicone rubber, such as RTV-2;

[0028] Then, shape memory alloy wire is used as core yarn, polyimide fiber is used as outer covering fiber, the core yarn and outer covering fiber are drafted and twisted together to form core-spun yarn, and the core-spun yarn is interwoven to prepare the thermal switch layer;

[0029] The light-absorbing and heating layer with a composite layer on the bottom is placed flat, and the phase change layer is covered on the side of the heat-conducting layer away from the metal layer, and then heated to 80-90°C, and then laminated and low-temperature cured (below the phase change temperature) to connect the phase change layer and the heat-conducting layer; then the heat switch layer is covered on the side of the phase change layer away from the heat-conducting layer, and finally laminated to connect the heat switch layer and the phase change layer. The purpose of heating to 80-90°C is to melt the phase change material inside the shell of the microcapsule (the phase change material inside the microcapsule melts while the shell of the microcapsule remains a solid protective layer) so that it can penetrate into the light-absorbing and heating layer and increase the contact area between the two. The shell of the microcapsule is made of a combination of one or more of polyurethane, polyurea, polymethyl methacrylate and melamine resin.

[0030] Phase change materials can absorb and release heat at a specific phase change temperature. Microencapsulating the phase change material protects it from the external environment while providing sufficient mechanical stability during the phase change process. Furthermore, the addition of the phase change material causes the phase change layer to undergo a phase change when absorbing heat, preventing reverse heat flow. The phase change material can also store heat during the phase change process. When the temperature on the heat-releasing side drops below the phase change temperature, the phase change material returns to its original state, releasing the stored heat to enhance the fabric's warmth retention. Specifically, the steps for microencapsulation of phase change materials are as follows: 1) emulsification and dispersion: the molten phase change material is emulsified by high-speed shearing in an aqueous phase containing a surfactant to form an oil-in-water system emulsion with a particle size of 1-50 μm; 2) interfacial polymerization: the oil phase of the monomer (such as HDI) is added to the oil-in-water system emulsion, diffused to the oil-water interface, and then an amine chain extender (such as ethylenediamine) is injected. A condensation reaction occurs at the interface at a temperature of 25-40°C to form a shell (such as polyurethane, polyurea), and the reaction time is 1-3 hours; 3) separation and purification: the system after the reaction is centrifuged or filtered to collect microcapsules, and then the residual monomers are removed by water washing, and finally the powder of the phase change material after microencapsulation is obtained by spray drying (the spray drying temperature is ≤80°C to prevent degradation of the microcapsule shell).

[0031] The shape memory alloy wire is a combination of one or more of Cu-Zn-Al, Cu-Al-Ni, and Ni-Ti. It contracts at 30-40°C (above the temperature transition point, Tg), closing the pores at the interlacing joints and preventing heat from flowing back. At 0-10°C (below the temperature transition point, Tg), it stretches, gradually increasing the pore size at the interlacing joints and allowing heat to flow forward. This intelligent thermal switch design automatically adjusts heat flow based on temperature changes, thereby improving the thermal management performance of the fabric.

[0032] According to some preferred implementation aspects of the present invention, the thickness of the phase change layer is 10-15 μm, and the thickness of the thermal switch layer is 40-80 μm.

[0033] According to some preferred embodiments of the present invention, the phase change material is a combination of one or more of n-alkanes, fatty acids, and polyethylene glycol. Specifically, the n-alkanes have specific carbon chain lengths, such as octacosane and nonacosane, while the polyethylene glycol has a low molecular weight, such as PEG 600, which has a molecular weight of 600 Da. In some embodiments of the present invention, the phase change temperature of the phase change material is required to be within the range of 20-35°C.

[0034] According to some preferred embodiments of the present invention, the second functional filament is prepared by the following method:

[0035] The modified heat storage powder and polyester particles are mixed in a mass ratio of 15-25:100, and the heat storage polyester particles are obtained after melt extrusion, granulation and drying. The heat storage polyester particles are spun and stretched to obtain the second functional filament.

[0036] According to some preferred embodiments of the present invention, the preparation method of the modified thermal storage powder is:

[0037] The thermal storage powder is ultrasonically treated in a 4%-10% by mass hydrochloric acid solution for 30-60 minutes, then washed until neutral to obtain a pretreated material. The pretreated material is then added to an ethanol solution containing a silane coupling agent and stirred at a constant temperature of 60-80°C for 1-3 hours. Finally, the modified thermal storage powder is dried. The drying temperature is above the boiling point of water but below the oxidation temperature of the thermal storage powder, and vacuum drying is used to ensure that the micropore moisture desorption rate of the modified thermal storage powder is greater than 99%, thereby preventing the formation of pores during the spinning process.

[0038] According to some preferred embodiments of the present invention, the solid-to-liquid ratio of the pretreated material to the ethanol solution is 1:15-30, and the mass percentage of the silane coupling agent in the ethanol solution is 2%-3%. The silane coupling agent reacts with the polyester to enhance interfacial bonding strength, thereby preventing yarn breakage during subsequent spinning.

[0039] According to some preferred embodiments of the present invention, the thermal storage powder is activated carbon micropowder or graphene composite powder. Because activated carbon contains impurities such as iron and / or calcium, which can reduce thermal storage efficiency, hydrochloric acid treatment increases the specific surface area of ​​the thermal storage powder, thereby enhancing its thermal energy storage density when blended with polyester.

[0040] According to some preferred embodiments of the present invention, in the step of mixing the modified thermal storage powder and polyester particles at a mass ratio of 15-25:100, the particle size distribution of the modified thermal storage powder is D50 of 5-10 μm; and the moisture content of the polyester particles is less than 0.1%. In some embodiments of the present invention, during the preparation of the modified thermal storage powder, the dried modified thermal storage powder is passed through an air flow classifier to extract powder with a D50 of 5-10 μm to ensure a uniform particle size distribution and reduce the problem of uneven powder dispersion caused by particle size differences. Furthermore, controlling the modified thermal storage powder within this particle size range can achieve a balance between thermal storage capacity and spinnability (to avoid clogging the spinneret).

[0041] Preferably, in some embodiments of the present invention, in the step of mixing the modified thermal storage powder and polyester particles in a mass ratio of 15-25:100, the modified thermal storage powder and dry polyester particles are placed into a high-speed mixer according to the mass ratio and mixed at a speed of 400-600 r / min for 3-10 minutes to allow the modified thermal storage powder to initially adhere. A second dispersant is then added, and the speed is then increased to 1100-1300 r / min and mixed for 8-15 minutes. The mass percentage of the second dispersant to the mass of the modified thermal storage powder is 0.3%-1%. The addition of the second dispersant ensures uniform dispersion of the modified thermal storage powder in the polyester.

[0042] According to some preferred embodiments of the present invention, in the step of spinning the second functional filament and the modal fiber to obtain the composite yarn, the second functional filament and the modal fiber are blended in a blending ratio of 6-7:3-4.

[0043] Another object of the present invention is to provide a heat-generating and warm-keeping fabric prepared by the preparation method as described above, wherein the heat-generating and warm-keeping fabric has a heat preservation rate of 80%-90%, an average temperature rise value of the fabric of 20-30°C, and a surface density of 100-250g / m 2 .

[0044] The thermal conversion and heat storage mechanism of the fabric in the present invention is as follows: when light is irradiated onto the light-absorbing and heat-generating layer, the C=C double bond structure on the light-absorbing material can absorb photons, and its electrons are excited from the ground state to the excited state, and then return to the ground state through non-radiative decay and radiative decay, releasing energy. In this process, the functional groups and carbon atom structure of the light-absorbing material play a key role; different functional groups and carbon atom arrangements affect the absorption of photons and the release of energy, thereby generating heat. After the heat conduction layer captures the heat, it transfers the heat unidirectionally to the heat storage layer through the phase change layer and the heat switch layer in sequence. The heat storage layer woven by the second functional filament stores the heat, thereby achieving the function of heat storage and warmth.

[0045] According to some preferred embodiments of the present invention, the heat-generating and thermal insulation fabric includes, from top to bottom, a light-absorbing and heat-generating layer, a composite layer, a phase change layer, a heat switch layer, and a heat storage layer. The composite layer includes, from top to bottom, a metal layer and a heat conduction layer. The metal layer is located on the side of the heat conduction layer away from the phase change layer.

[0046] According to some preferred embodiments of the present invention, the heat storage layer is made by interweaving composite yarns. The composite yarns are covered yarns, which, from the inside out, include a core filament, a covering filament, and a wrapping filament. The core filament is modal fiber, and the covering filament is a second functional filament. The covering filament covers the core filament, and the wrapping filament wraps the covering filament. In some embodiments of the present invention, the second functional filament is covered on the outside, and the modal fiber is used as a staple fiber and positioned in the middle of the yarn body, which helps to improve the cohesion between the staple fibers, thereby enhancing the strength and elongation properties of the composite yarn. In addition, the thickness of the heat storage layer is 0.4-0.6 mm.

[0047] Due to the adoption of the above technical scheme, compared with the existing technology, the benefits of the present invention are as follows: the heat-generating and thermal insulation fabric of the present invention and its preparation method are prepared by respectively preparing a light-absorbing and heating layer (fabric surface layer), a composite layer, a phase change layer and a heat switch layer and a heat storage layer (fabric bottom layer), wherein the composite layer, the phase change layer and the heat switch layer constitute the intermediate layer between the surface layer and the bottom layer of the fabric; the light-absorbing and heating layer is made of the first functional filament, and the first functional filament is added with light-absorbing material. Combined with the self structure of the first functional filament, the light-absorbing and heating layer has a strong light-absorbing and heating function, and then the heat is unidirectionally conducted from the light-absorbing and heating layer to the heat storage layer through the composite layer, the phase change layer and the heat switch layer; and the heat storage layer is made of the second functional filament, and the second functional filament is added with heat storage powder. Combined with the fabric structure design of the heat storage layer, the heat conducted from the composite layer, the phase change layer and the heat switch layer can be effectively retained, thereby effectively improving the thermal insulation effect of the fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in 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 only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0049] Figure 1 This is a diagram showing the heat generation and heat storage principle of the heat-generating and thermal insulation fabric of the present invention;

[0050] Figure 2 is a schematic diagram of the three-dimensional structure of the first functional filament of the present invention;

[0051] Figure 3 Schematic diagram of the three-dimensional structure of the thermal switch layer of the present invention at high temperature;

[0052] Figure 4 Schematic diagram of the three-dimensional structure of the thermal switch layer of the present invention at low temperature;

[0053] Figure 5 Schematic diagram of the three-dimensional structure of the composite yarn in the heat storage layer of the present invention.

[0054] Wherein, the accompanying drawings are marked as follows:

[0055] Light-absorbing and heat-generating layer-1, heat-storage layer-2, composite yarn-21, second functional filament-211, modal fiber-212. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0057] The present invention provides a heat-generating and thermal insulation fabric, which comprises, from top to bottom, a light-absorbing and heat-generating layer 1, a composite layer, a phase change layer, a heat switch layer and a heat storage layer 2. The composite layer comprises, from top to bottom, a metal layer and a heat conduction layer. The metal layer is located on the side of the heat conduction layer away from the phase change layer. The two sides of the metal layer are respectively bonded to the bottom surface of the light-absorbing and heat-generating layer 1 and the top surface of the heat conduction layer. The two sides of the phase change layer are respectively bonded to the bottom surface of the heat conduction layer and the top surface of the heat switch layer. The bottom surface of the heat switch layer is bonded to the top surface of the heat storage layer 2.

[0058] Among them, the thickness of the light-absorbing and heating layer 1 is 0.2-0.5mm, the thickness of the heat-conducting layer is 5-20μm, the thickness of the phase change layer is 10-15μm, the thickness of the heat switch layer is 40-80μm, and the thickness of the heat storage layer 2 is 0.4-0.6mm.

[0059] Furthermore, the fabric tightness of the light-absorbing and heating layer 1 is 40%-60%, and the light-absorbing and heating layer 1 includes warp yarns and weft yarns. The warp yarns and weft yarns of the light-absorbing and heating layer 1 are both first functional filaments. The first functional filaments are obtained by uniformly mixing 1,6-hexamethylenediamine, sebacic acid chloride and light-absorbing materials and then polymerizing the mixture to obtain a modified polyamide melt. The modified polyamide melt is spun to obtain the first functional filaments, such as Figure 1 As shown, the first functional filament of the present invention is a modified polyamide filament, and its structure is that a light-absorbing material is attached to the outer wall of the polyamide filament; the solar light absorption rate of the first functional filament is greater than or equal to 92%.

[0060] The heat storage layer 2 also includes warp yarns and weft yarns, and the warp yarns and weft yarns of the heat storage layer 2 are composite yarns 21, such as Figure 5As shown, the composite yarn 21 is a covered yarn. The covered yarn includes, from the inside out, a core filament, a covering filament, and a wrapping filament. The core filament is a modal fiber 212, and the covering filament is a second functional filament 211. The covering filament covers the core filament, and the wrapping filament wraps the covering filament. The second functional filament 211 is obtained by mixing a modified thermal storage powder with polyester particles, melt-extruding, granulating, and drying, followed by spinning and stretching.

[0061] In addition, if Figure 1 As shown, the heat conduction layer in the composite layer, together with the phase change layer and heat switch layer below it, forms a directional heat flow drive path from the light-receiving side (the side of the light-absorbing and heat-generating layer 1 away from the composite layer) to the heat-retaining side (heat storage layer 2), which can minimize the reverse dissipation of heat. The heat conduction layer is made of a heat conductive material, the phase change layer is made of a phase change material, and the heat switch layer includes warp and weft yarns. Both the warp and weft yarns of the heat switch layer are core-spun yarns, which include a core yarn and an outer fiber wrapped around the core yarn. The core yarn is made of shape memory alloy wire, and the outer fiber is made of polyimide fiber.

[0062] The present invention also provides a method for preparing a heat-generating and thermal-insulating fabric, comprising the following steps:

[0063] Step 1: Prepare the light-absorbing and heating layer 1

[0064] 1,6-hexamethylenediamine, sebacic acid chloride, and a light-absorbing material are premixed at 50-60°C for 20-30 minutes to achieve uniform mixing, then pre-condensed at 170-190°C for 1-2 hours, and finally polycondensed under reduced pressure at 230-250°C for 2-3 hours. After the polymerization reaction, a modified polyamide melt is obtained. The modified polyamide melt is then spun to obtain a first functional filament, which is then interwoven with the first functional filament as warp and weft to produce a light-absorbing and heat-generating layer 1. The mass ratio of 1,6-hexamethylenediamine to sebacic acid chloride is 5-9:1-3, and the mass proportion of the light-absorbing material relative to 1,6-hexamethylenediamine is 3%-10%. The light-absorbing material is preferably carboxylated graphene quantum dots.

[0065] Step 2: Prepare the composite layer

[0066] The composite layer includes a metal layer and a heat-conducting layer. A 1-3 nm thick metal layer is first sputtered onto the bottom surface of the light-absorbing and heat-generating layer 1. A heat-conducting material is selected and carboxylated or amino-treated to impart a stable charge in a solvent (e.g., water, ethanol, or DMF). The treated heat-conducting material is then uniformly dispersed in the solvent using an ultrasonic disruptor. An appropriate amount of a first dispersant (e.g., SDS or SDBS) is added to the system to form a stable, charged colloidal dispersion. The dispersion is then placed into an electrolytic cell. The light-absorbing and heat-generating layer 1, with the metal layer sputtered onto its bottom surface, serves as the working electrode and is simultaneously immersed in the electrolytic cell containing the dispersion, along with a counter electrode, in parallel. The spacing between the two electrodes is maintained constant. Deposition is performed at a constant voltage or current, allowing the heat-conducting material to deposit onto the surface of the metal layer to form a heat-conducting layer. After deposition is complete, the working electrode is removed and thoroughly rinsed with deionized water to remove any residual electrolyte and the first dispersant. In addition, according to actual conditions, the light-absorbing and heat-generating layer 1 and the composite layer can be heat-treated at a temperature that they can tolerate, so as to enhance the bonding force between the heat-conducting layer and the metal layer.

[0067] The metal layer is made of gold or platinum; the heat conduction material is preferably carbon nanotubes, which have extremely high axial thermal conductivity and elastic modulus, and can effectively transfer heat along the axial direction of the carbon nanotubes, thereby improving the heat conduction performance.

[0068] Step 3: Prepare the phase change layer and thermal switch layer

[0069] First, a phase change material is selected and microencapsulated, then evenly dispersed in a matrix. Low-temperature curing is then performed to obtain a phase change layer. A shape memory alloy wire is then used as the core yarn, and polyimide fiber is used as the outer covering fiber. The core yarn and outer covering fiber are then drafted and twisted together to form a core-spun yarn. The core-spun yarn is then interwoven in warp and weft to produce a thermal switch layer. A light-absorbing, heat-generating layer (1) with a composite layer on its bottom is then laid flat with the thermal conductive layer facing upward. The phase change layer is then placed on the side of the thermal conductive layer facing away from the metal layer. The layer is then heated to 80-90°C, laminated, and low-temperature cured to connect the phase change layer and the thermal switch layer. The thermal switch layer is then placed on the side of the phase change layer facing away from the thermal conductive layer, and finally laminated to connect the thermal switch layer and the phase change layer.

[0070] The phase change material is a combination of one or more of normal alkanes, fatty acids and polyethylene glycol, the matrix is ​​an addition-type silicone rubber, such as RTV-2; the shape memory alloy wire is a combination of one or more of Cu-Zn-Al, Cu-Al-Ni and Ni-Ti, and the shape memory alloy wire of the present invention can shrink at 30-40°C, such as Figure 3 As shown, the pores at the interweaving are closed, preventing heat from flowing back; at 0-10℃, it stretches, as shown Figure 4As shown in the figure, the pore size at the interweaving point gradually increases, allowing heat to flow through, and can automatically adjust the heat flow according to temperature changes, which is beneficial to improving the thermal management performance of the fabric.

[0071] Step 4: Prepare the heat storage layer 2

[0072] The thermal storage powder is ultrasonically treated in a 4%-10% by mass hydrochloric acid solution for 30-60 minutes, then washed until neutral to obtain a pretreated material. The pretreated material is then added to an ethanol solution containing a silane coupling agent and stirred at 60-80°C for 1-3 hours. Finally, the modified thermal storage powder is dried and passed through an air classifier to obtain a particle size distribution of 5-10 μm. The solid-to-liquid ratio of the pretreated material to the ethanol solution is 1:15-30, and the silane coupling agent content in the ethanol solution is 2%-3% by mass. The drying temperature is above the boiling point of water but below the oxidation temperature of the thermal storage powder. A vacuum drying process is used to ensure a micropore moisture desorption rate of >99% to prevent the formation of pores during the spinning process. The thermal storage powder is activated carbon micropowder or graphene composite powder.

[0073] The modified thermal storage powder and polyester particles with a moisture content of less than 0.1% are then put into a high-speed mixer in a mass ratio of 15-25:100, and mixed at a speed of 400-600 r / min for 3-10 minutes to allow the modified thermal storage powder to initially adhere; a second dispersant is then injected, and the mass of the second dispersant accounts for 0.3%-1% of the mass of the modified thermal storage powder; the speed is then increased to 1100-1300 r / min and mixed for 8-15 minutes to ensure that the modified thermal storage powder and the polyester particles are evenly mixed, and then the thermal storage polyester particles are obtained after melt extrusion, granulation and drying, and the thermal storage polyester particles are spun and stretched to obtain the second functional filament 211.

[0074] Finally, the siro spinning technology is used to blend the second functional filament 211 with the modal fiber 212 in a blending ratio of 6-7:3-4 to produce a composite yarn 21, and then the composite yarn 21 is used as the warp and weft yarns, and the heat storage layer 2 is produced by interweaving the warp and weft.

[0075] Step 5: Connect the top surface of the heat storage layer 2 and the bottom surface of the heat switch layer by sewing or using spacer wire to connect the upper and lower layers to obtain a heat-generating and warm-keeping fabric.

[0076] Example 1

[0077] This embodiment provides a method for preparing a heat-generating and warm-keeping fabric and a heat-generating and warm-keeping fabric prepared by the method, wherein the method comprises the following steps:

[0078] Step 1: Prepare the light-absorbing and heating layer

[0079] 1,6-hexamethylenediamine, sebacic acid chloride and carboxylated graphene quantum dots were premixed at 60°C for 30 minutes under nitrogen protection to mix evenly, then pre-condensed at 180°C for 1 hour, and finally polycondensed under reduced pressure at 240°C for 2 hours. After the polymerization reaction, a modified polyamide melt was obtained; the modified polyamide melt was then spun to obtain a first functional filament, which was used as the warp and weft yarns, and the light-absorbing and heating layer was obtained by interweaving the warp and weft yarns. Among them, the mass ratio of 1,6-hexamethylenediamine to sebacic acid chloride was 7:3, and the mass proportion of the light-absorbing material relative to 1,6-hexamethylenediamine was 5%.

[0080] Step 2: Prepare the composite layer

[0081] The composite layer includes a metal layer and a heat-conducting layer. First, a 1nm thick platinum metal layer is sputtered on the bottom surface of the light-absorbing and heat-generating layer. An appropriate amount of carbon nanotubes is weighed and carboxylated. The treated carbon nanotubes are then uniformly dispersed in a solvent using an ultrasonic crusher. An appropriate amount of the first dispersant SDS is added to the system to form a stable, charged colloidal dispersion. The dispersion is then loaded into an electrolytic cell. The light-absorbing and heat-generating layer with the platinum metal layer sputtered on the bottom surface is used as the working electrode. It is immersed in the electrolytic cell containing the dispersion in parallel with the counter electrode, ensuring a constant distance between the two electrodes. Deposition is performed at a constant voltage so that the carbon nanotubes are deposited on the surface of the platinum metal layer to form a heat-conducting layer. After deposition is completed, the working electrode is removed and thoroughly washed with deionized water to remove residual electrolyte and SDS.

[0082] Step 3: Prepare the phase change layer and thermal switch layer

[0083] An appropriate amount of octacosane is weighed and microencapsulated, then uniformly dispersed in RTV-2. The phase change layer is then cured at low temperature. A Cu-Zn-Al shape memory alloy wire is used as the core yarn, and polyimide fibers are used as the outer sheath. The core yarn and outer sheath are then drafted and twisted together to form a core-spun yarn, which is then interwoven in warp and weft to form a thermal switch layer. A light-absorbing, heat-generating layer with a composite layer on its bottom is placed flat with the thermal conductive layer facing upward. The phase change layer is then placed on the side of the thermal conductive layer facing away from the metal layer. The layer is then heated to 80°C, laminated, and cured at low temperature to connect the phase change layer and the thermal switch layer. The thermal switch layer is then placed on the side of the phase change layer facing away from the thermal conductive layer, and finally laminated to connect the thermal switch layer and the phase change layer.

[0084] Step 4: Prepare the thermal storage layer

[0085] An appropriate amount of activated carbon micropowder is ultrasonically treated in a 4% by mass hydrochloric acid solution for 30 minutes, then washed until neutral to obtain a pretreated material. The pretreated material is then added to an ethanol solution containing a silane coupling agent and stirred at 70°C for 2 hours. Finally, the pretreated material is treated in a vacuum drying oven at 120°C for 4 hours to obtain a modified activated carbon micropowder. The dried modified activated carbon micropowder is then passed through an air flow classifier to obtain a powder with a D50 of 5-10 μm to ensure uniform particle size distribution. The solid-to-liquid ratio of the pretreated material to the ethanol solution is 1:20, and the mass percentage of the silane coupling agent in the ethanol solution is 2%.

[0086] The modified activated carbon micropowder and polyester particles with a moisture content of less than 0.1% are then put into a high-speed mixer in a mass ratio of 25:100, and mixed at a speed of 500 r / min for 5 minutes to allow the modified thermal storage powder to initially adhere; polyethylene wax is then injected, and the mass of the polyethylene wax accounts for 0.5% of the mass of the modified thermal storage powder; the speed is then increased to 1200 r / min and mixed for 10 minutes to ensure that the modified thermal storage powder and the polyester particles are evenly mixed, and then melt-extruded, granulated and dried in a twin-screw extruder to obtain thermal storage polyester particles, which are then spun and stretched to obtain second functional filaments.

[0087] Finally, the siro spinning technology was used to blend the second functional filament with modal fiber with a fineness of 1.2dtex in a blending ratio of 6:4 to produce a composite yarn. The composite yarn was then used as warp and weft yarns, and the heat storage layer was produced by interweaving the warp and weft.

[0088] Step 5: Connect the top surface of the heat storage layer and the bottom surface of the heat switch layer by sewing with sewing thread to obtain a heat-generating and warm fabric.

[0089] The fabric prepared in this embodiment was tested according to the method in GB / T 18319-2019 "Test method for light and heat storage performance of textiles", and the average temperature rise value of the fabric was measured to be 25°C and the heat preservation rate was 85%; according to the fabric surface density (square meter weight) test, the surface density of the fabric was measured to be 225g / m 2 .

[0090] Comparative Example 1

[0091] The difference between Comparative Example 1 and Example 1 is that in step 1 of Comparative Example 1, graphene quantum dots are not added during the polymerization reaction, and the remaining steps are the same.

[0092] The fabric prepared in this comparative example was tested according to the method in GB / T 18319-2019 "Test method for light and heat storage performance of textiles", and the average temperature rise value of the fabric was measured to be 0°C and the thermal insulation rate was 84%.

[0093] Comparative Example 2

[0094] The difference between Comparative Example 2 and Example 1 is that the preparation method of Comparative Example 2 does not include step 2, and the remaining steps are the same, that is, the fabric prepared in Comparative Example 2 does not include a composite layer.

[0095] The fabric prepared in this comparative example was tested according to the method in GB / T 18319-2019 "Test method for light and heat storage performance of textiles", and the average temperature rise value of the fabric was measured to be 10°C and the thermal insulation rate was 60%.

[0096] Comparative Example 3

[0097] The difference between Comparative Example 3 and Example 1 is that in step 3 of Comparative Example 3, no phase change layer is prepared, and the remaining steps are the same, that is, the fabric prepared in Comparative Example 3 does not include a phase change layer.

[0098] The fabric prepared in this comparative example was tested according to the method in GB / T 18319-2019 "Test method for light and heat storage performance of textiles", and the average temperature rise value of the fabric was measured to be 13°C and the thermal insulation rate was 50%.

[0099] Comparative Example 4

[0100] The difference between Comparative Example 4 and Example 1 is that the thermal switch layer is not prepared in step 3 of Comparative Example 4, and the remaining steps are the same, that is, the fabric prepared in Comparative Example 4 does not include a thermal switch layer.

[0101] The fabric prepared in this comparative example was tested according to the method in GB / T 18319-2019 "Test method for light and heat storage performance of textiles", and the average temperature rise value of the fabric was measured to be 15°C and the thermal insulation rate was 50%.

[0102] Comparative Example 5

[0103] The difference between Comparative Example 5 and Example 1 is that the preparation method of Comparative Example 5 does not include step 4, and the remaining steps are the same, that is, the fabric prepared in Comparative Example 5 does not include a heat storage layer.

[0104] The fabric prepared in this comparative example was tested according to the method in GB / T 18319-2019 "Test method for light and heat storage performance of textiles", and the average temperature rise value of the fabric was measured to be 20°C and the thermal insulation rate was 30%.

[0105] Comparative Example 6

[0106] The difference between Comparative Example 6 and Example 1 is that in step 4 of Comparative Example 6, modified activated carbon powder is not prepared, and the heat storage polyester particles are directly spun and stretched to obtain polyester filaments, which are then blended with modal fibers with a fineness of 1.2 dtex in a blending ratio of 6:4 to obtain composite yarns, and the composite yarns are used as warp and weft yarns, and the heat storage layer is obtained by interweaving the warp and weft. The remaining steps are the same.

[0107] The fabric prepared in this comparative example was tested according to the method in GB / T 18319-2019 "Test method for light and heat storage performance of textiles", and the average temperature rise value of the fabric was measured to be 20°C and the thermal insulation rate was 60%.

[0108] Results and Discussion

[0109] It can be seen from the test data of Example 1 and Comparative Examples 1 to Comparative Examples 6 that the fabric prepared in Example 1 has the property of absorbing light and generating heat, and the spontaneously generated heat reaches the heat storage layer after unidirectional transfer through the composite layer, phase change layer and thermal switch layer. The heat can be stored in the heat storage layer, thereby effectively storing heat. The average temperature rise value and thermal insulation rate of the fabric in Example 1 are the highest compared with the comparative examples.

[0110] In Comparative Examples 1 to 6, since no light-absorbing material is added to Comparative Example 1, the fabric cannot absorb sunlight for self-heating, and the fabric cannot achieve temperature increase at low temperatures. Comparative Examples 2, 3 and 4 respectively have poor heat conductivity due to the lack of a composite layer, a phase change layer and a heat switch layer, and the increased temperature cannot be transferred well. Comparative Examples 5 and 6 respectively have no heat storage layer and no heat storage powder is added to the heat storage layer, which results in the fabric not being able to store heat well and large heat loss. It can be seen that the present invention innovatively prepares a composite layer, a phase change layer and a heat switch layer between the surface layer and the bottom layer of the fabric, establishes a heat flow directional driving mechanism from the light-receiving surface to the warm-keeping surface, minimizes heat reverse dissipation, and effectively stores heat in combination with the heat storage layer, thereby effectively improving the thermal insulation rate of the fabric.

[0111] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a heat-generating and warm-keeping fabric, characterized in that: The steps include: preparing first functional filaments, and weaving the first functional filaments to prepare a light-absorbing and heat-generating layer, wherein the fabric tightness of the light-absorbing and heat-generating layer is 40%-60%; Prepare a composite layer on the bottom surface of the light-absorbing and heat-generating layer, wherein the composite layer includes a heat-conducting layer; Prepare a phase change layer and a heat switch layer, and sequentially connect the phase change layer and the heat switch layer to the light-absorbing and heat-generating layer, wherein the phase change layer is located between the heat conduction layer and the heat switch layer; preparing a second functional filament, spinning the second functional filament and modal fiber to obtain a composite yarn, and then interweaving the composite yarn to obtain a heat storage layer; The top surface of the heat storage layer is connected to the bottom surface of the heat switch layer to obtain the heat-generating and warm-keeping fabric.

2. The preparation method according to claim 1, characterized in that The first functional filament is prepared by the following method: 1,6-hexamethylenediamine, sebacic acid chloride and light-absorbing material are uniformly mixed and polymerized to obtain a modified polyamide melt, and the modified polyamide melt is spun to obtain the first functional filament, wherein the solar light absorption rate of the first functional filament is greater than or equal to 92%.

3. The preparation method according to claim 2, characterized in that The mass ratio of the 1,6-hexamethylenediamine to sebacic acid chloride is 5-9:1-3, and the mass proportion of the light-absorbing material relative to the 1,6-hexamethylenediamine is 3%-10%.

4. The preparation method according to claim 2, characterized in that The light-absorbing material is carboxylated graphene quantum dots.

5. The preparation method according to claim 1, characterized in that The composite layer further includes a metal layer, and the method for preparing the composite layer on the bottom surface of the light-absorbing and heat-generating layer is: First, a metal layer is sputtered on the bottom surface of the light-absorbing and heat-generating layer, a heat-conducting material is selected and the surface of the heat-conducting material is treated to prepare a dispersion liquid, and the light-absorbing and heat-generating layer with a metal layer sputtered on the bottom surface is immersed in an electrolytic tank filled with the dispersion liquid as a working electrode for deposition, so that the heat-conducting material is deposited on the surface of the metal layer to form a heat-conducting layer.

6. The preparation method according to claim 5, characterized in that The thickness of the metal layer is 1-3 nm, and the material of the metal layer is gold or platinum.

7. The preparation method according to claim 5, characterized in that The heat conductive material is carbon nanotubes.

8. The preparation method according to claim 7, characterized in that The method for surface treating the heat conductive material is: performing carboxylation or amination treatment on the heat conductive material.

9. The preparation method according to claim 5, characterized in that The method of preparing the phase change layer and the thermal switch layer, and sequentially connecting the phase change layer and the thermal switch layer to the light-absorbing and heating layer is as follows: First, a phase change material is selected and microencapsulated, and then uniformly dispersed in a matrix, and then low-temperature solidified to obtain the phase change layer; Then, shape memory alloy wire is used as core yarn, polyimide fiber is used as outer covering fiber, the core yarn and outer covering fiber are drafted and twisted together to form core-spun yarn, and the core-spun yarn is interwoven to prepare the thermal switch layer; The light-absorbing and heating layer with a composite layer on the bottom is placed flat, and the phase change layer is covered on the side of the heat conduction layer away from the metal layer, and then heated to 80-90°C, and then laminated and low-temperature cured to connect the phase change layer and the heat conduction layer; then the thermal switch layer is covered on the side of the phase change layer away from the heat conduction layer, and finally laminated to connect the thermal switch layer and the phase change layer.

10. The preparation method according to claim 9, characterized in that The thickness of the phase change layer is 10-15 μm, and the thickness of the thermal switch layer is 40-80 μm.

11. The preparation method according to claim 9, characterized in that The phase change material is a combination of one or more of normal alkanes, fatty acids and polyethylene glycol.

12. The preparation method according to claim 1, characterized in that The second functional filament is prepared by the following method: The modified heat storage powder and polyester particles are mixed in a mass ratio of 15-25:100, and the heat storage polyester particles are obtained after melt extrusion, granulation and drying. The heat storage polyester particles are spun and stretched to obtain the second functional filament.

13. The preparation method according to claim 12, characterized in that The preparation method of the modified thermal storage powder is as follows: The thermal storage powder is placed in a hydrochloric acid solution with a mass percentage of 4%-10%, ultrasonically treated for 30-60 minutes, and then washed until neutral to obtain a pretreated material; the pretreated material is then added to an ethanol solution containing a silane coupling agent and stirred at a constant temperature of 60-80°C for 1-3 hours, and finally dried to obtain the modified thermal storage powder.

14. The preparation method according to claim 13, characterized in that The solid-liquid ratio of the pretreated material to the ethanol solution is 1:15-30, and the mass percentage of the silane coupling agent in the ethanol solution is 2%-3%.

15. The preparation method according to claim 13, characterized in that The heat storage powder is activated carbon micropowder or graphene composite powder.

16. The preparation method according to claim 12, characterized in that In the step of mixing the modified thermal storage powder and polyester particles in a mass ratio of 15-25:100, the particle size distribution of the modified thermal storage powder is D50 of 5-10 μm; and the moisture content of the polyester particles is less than 0.1%.

17. The preparation method according to claim 1, characterized in that In the step of spinning the second functional filament and the modal fiber to obtain the composite yarn, the second functional filament and the modal fiber are blended according to a blending ratio of 6-7:3-4.

18. A heat-generating and warm-keeping fabric, characterized in that: The heat-generating and warming fabric is prepared by the preparation method according to any one of claims 1 to 17, and the heat preservation rate of the heat-generating and warming fabric is 80%-90%, and the surface density is 100-250g / m 2 .

19. The heat-generating and thermal insulation fabric according to claim 18, characterized in that: From top to bottom, it includes a light-absorbing and heating layer, a composite layer, a phase change layer, a heat switch layer and a heat storage layer. The composite layer includes a metal layer and a heat conduction layer from top to bottom. The metal layer is located on the side of the heat conduction layer away from the phase change layer.

20. The heat-generating and thermal insulation fabric according to claim 19, characterized in that: The heat storage layer is made by interweaving composite yarns, wherein the composite yarns are covered yarns, and the covered yarns include core wires, covering wires and wrapping wires from the inside to the outside. The core wires are modal fibers, and the covering wires are second functional filaments. The covering wires cover the core wires, and the wrapping wires wrap the covering wires.

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