A nylon filament, core-spun yarn, heat-retaining and warm fabric and its preparation method

Abstract

This invention discloses a nylon filament, core-spun yarn, heat-retaining and warm fabric, and its preparation method. The nylon filament includes a shell and a cavity located inside the shell. The cavity includes multiple spaced-apart cavity units. The shell includes a shell body, a first column, and a connecting part located between two adjacent cavity units. The connecting part connects the first column and the shell body. The multiple cavity units are arranged circumferentially along the first column, and the center of the first column coincides with the center of the nylon filament. The area of ​​the cavity in the cross-section of the nylon filament accounts for 20% to 30%, and the cavity is used to store air. The core-spun yarn includes an inner core layer and an outer sheath layer wrapped around the inner core layer. The inner core layer includes multiple nylon filaments, and the outer sheath layer includes multiple heat-retaining fibers. The fabric includes a surface layer and an inner layer that are bonded together. Both the surface layer and the inner layer are prepared by warp and weft interlacing of the core-spun yarn. The heat-retaining and warm fabric of this invention can improve and enhance the heat-retaining function of the yarn and fabric while reducing the weight of the fabric.

Description

Technical Field

[0001] This invention belongs to the field of textile technology, specifically relating to a nylon filament, core-spun yarn, heat-retaining and warm fabric, and its preparation method. Background Technology

[0002] With the development of modern technology, people's requirements for thermal insulation fabrics have gone beyond simply providing thick, warm, and cold-proof materials. They now seek new types of fabrics that prioritize intelligent heat storage and lightweight design while still meeting the requirements for warmth and heat retention. Currently, most heat-retaining yarns and fabrics on the market only improve one aspect of their structure or composition, or use multi-layered fabric composites to enhance heat storage performance. While this improves the heat storage performance to some extent, it results in thick and heavy fabrics that are not lightweight.

[0003] For example, Chinese invention patent CN118407263B, entitled "A Graphene Heat Storage Fabric and Its Preparation Method and Application," discloses a composite finishing agent that coats graphene encapsulated in polyvinyl acetal onto the fabric layer to form a heat storage layer. This only improves the heat storage performance from the raw material perspective; however, the graphene coating reduces the fabric's breathability, and the coating's bonding performance with the fabric is low, resulting in reduced abrasion resistance. Similarly, Chinese utility model patent CN209537717U, entitled "An Uncoated, Linerless, Downproof Heat Storage Yarn Fabric," discloses an improvement in the performance of the heat storage fabric through a specific weave structure (comprising six warp yarns and two weft yarns interwoven), but the heat storage effect is not significant.

[0004] How to reduce the weight of fabrics to make them lighter and more comfortable to wear, while still ensuring the fabrics have good heat retention and warmth retention properties, is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, in order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a nylon filament, core-spun yarn, heat-retaining and warm fabric and its preparation method, which can improve and enhance the heat-retaining function of the yarn and fabric, while reducing the weight of the fabric.

[0006] One object of the present invention is to provide a nylon filament comprising a shell and a cavity located inside the shell. The cavity comprises a plurality of spaced-apart cavity units. The shell comprises a shell body, a first column, and a connecting portion located between two adjacent cavity units. The connecting portion is used to connect the first column and the shell body. The plurality of cavity units are arranged circumferentially along the first column, and the center of the first column coincides with the center of the nylon filament. The area of ​​the cavity in the cross-section of the nylon filament accounts for 20% to 30%, and the length of the cavity is equal to the length of the shell. The cavity is used to store air.

[0007] By designing cavities inside the shell of the nylon filament to store air, the static air inside the nylon filament will not be completely lost when it is compressed, and can be preserved for a longer period of time, which is beneficial to improving the heat storage performance of the nylon filament.

[0008] According to some preferred embodiments of the invention, each cavity unit includes a plurality of spaced-apart cavity lobes, and at least one cavity lobe in each cavity unit has a length greater than the length of the remaining cavity lobes. Here, the length of the cavity lobe refers to the distance between the two ends of the cavity lobe in the cross-section of the nylon filament.

[0009] According to some preferred embodiments of the invention, the width of each cavity flap gradually increases from one end near the center of the nylon filament to the other. This arrangement makes the structure of each cavity flap more stable, resulting in less deformation under compression and retaining more residual still air.

[0010] According to some preferred embodiments of the invention, the plurality of cavity petals in each cavity unit are connected to each other at the ends near the center of the nylon filament, and the plurality of cavity petals in each cavity unit are spaced apart at the ends away from the center of the nylon filament.

[0011] According to some preferred embodiments of the invention, each cavity unit has a spacer between two adjacent cavity lobes, one end of the spacer being connected to the housing body, and the other end of the spacer extending toward the first column.

[0012] According to some preferred embodiments of the present invention, each cavity unit includes a main cavity lobe and symmetrically arranged auxiliary cavity lobes on both sides of the main cavity lobe, wherein the length of the main cavity lobe is greater than the length of the auxiliary cavity lobes. This arrangement is a preferred configuration of the cavity unit, which makes the cavity structure more stable.

[0013] Another object of the present invention is to provide a method for preparing the nylon filament as described above, comprising the following steps:

[0014] The nylon filament is obtained by mixing a heat storage promoter with a solution containing modified nylon and then spinning it; the thermal conductivity of the modified nylon is 0.128–0.151 W / (m·℃). The purpose of preparing modified nylon is to reduce its original thermal conductivity by modifying nylon, thereby improving its warmth retention.

[0015] According to some preferred embodiments of the present invention, the solution containing modified nylon is a modified nylon melt solution obtained by adding modified nylon melt to a solvent and mixing them uniformly; the modified nylon melt is prepared by melting nylon chips and then copolymerizing, surface crosslinking, or enzyme modification. Specifically, copolymerization modification involves introducing other monomers, such as ethylene glycol or melamine cyanurate, during the nylon polymerization process to form copolymers, reducing the crystallinity of the fibers and improving their warmth retention; or grafting hydrophilic polymers, such as polyethylene glycol, onto the surface of the nylon fibers to increase the hydrophilicity of the nylon fiber surface, promote water vapor adsorption, and improve the warmth retention. Surface crosslinking involves connecting polymer chains on the surface of the nylon fibers with chemical crosslinking agents to form a network structure, thereby improving its warmth retention. Enzymatic modification involves selectively degrading specific chemical bonds (amide bonds) on the surface of nylon fibers to alter the structure and properties of the nylon fiber surface, thereby improving its warmth retention and ultimately obtaining modified nylon with a low thermal conductivity (0.128–0.151 W / (m·℃)).

[0016] Specifically, the copolymerization modification method is as follows: First, ethylene glycol is subjected to an esterification reaction under excess organic acid (containing only two carboxyl groups) at a reaction temperature of 200–240°C for 3–5 hours to obtain a carboxyl-terminated polyester material. Then, nylon chips are added, and the temperature is further increased until the nylon chips are in a molten state. At this point, the hydroxyl groups in the nylon melt undergo an esterification grafting reaction with the carboxyl groups on the aforementioned polyester material to obtain modified nylon melt. The crystallinity of the modified nylon is reduced compared to the original, which can lower its thermal conductivity.

[0017] According to some preferred embodiments of the present invention, the method of spinning after mixing the heat storage accelerator with a solution containing modified nylon comprises: adding the heat storage accelerator to a modified nylon melt solution and mixing evenly to obtain a mixed spinning solution; extruding the spinning solution through a spinneret to form a filament bundle; then subjecting the bundle to monomer suction, side-blowing cooling, bundling and oiling, stretching and setting, web interlacing, and winding to obtain the nylon filament; the mass ratio of the modified nylon melt to the heat storage accelerator in the spinning solution is 95–99:1. The stretching is performed at a temperature of 75–90°C, and the yarn fineness after stretching ranges from 70–90D; the spinning temperature is 270–320°C, the spinning speed is 800–1300 m / min, and the winding speed is 4500–5000 m / min. Furthermore, the shape of the spinneret is designed according to the cross-sectional shape of the target nylon filament.

[0018] According to some preferred embodiments of the present invention, the heat storage promoter includes a light-absorbing material, which is one or more selected from nano-ceramic particles, graphene, carbon nanotubes, carbon black, carbon dots, MXene, zirconium carbide, and silicon carbide. Furthermore, the heat storage promoter also includes a dispersant and a coupling agent, wherein the dispersant accounts for 7% to 8% by mass and the coupling agent accounts for 3% to 4% by mass; when the light-absorbing material is nano-ceramic particles, its average particle size is 50 to 100 nm, and its composition is one or more selected from nano-alumina and nano-silica.

[0019] This invention also provides a core-spun yarn, comprising an inner core layer and an outer sheath layer surrounding the inner core layer. The inner core layer comprises multiple nylon filaments as described above, and the outer sheath layer comprises multiple heat-retaining fibers. Core-spun composites of nylon filaments and other heat-retaining fibers can yield yarns with stronger heat-retaining properties; wherein the nylon filaments have a density of 70–90 D and a weight per square meter of 160–200 g / m². 2 The fineness of the core-spun yarn is 14–18 tex.

[0020] According to some preferred embodiments of the present invention, the mass percentage of nylon filament in the core-spun yarn is 60% to 70%.

[0021] According to some preferred embodiments of the present invention, the outer surface of the outer skin layer is further coated with phase change microcapsules, each microcapsule comprising a phase change core and a shell for encapsulating the core. The phase change core is made of one or more of paraffin wax, fatty acids, and fatty alcohols. The addition of phase change microcapsules enhances the yarn's absorption of light and heat. The shell is made of one or more of polyurethane, polymethyl methacrylate, and urea-formaldehyde resin. The phase change microcapsules can improve the yarn's heat storage and insulation properties through photothermal conversion; specifically, they primarily utilize the phase change core within them to absorb and release heat through phase change, thereby storing energy.

[0022] According to some preferred embodiments of the present invention, the heat-storing fiber is volcanic rock heat-storing fiber or spectral heat-storing fiber. Volcanic rock fiber has a unique microporous structure and a large specific surface area, enabling it to absorb and store more heat. Simultaneously, it is rich in metallic elements, which can absorb thermal energy, thus enhancing the heat storage capacity of the fabric. Furthermore, volcanic rock fiber can release far-infrared rays, which can penetrate deep into the subcutaneous tissue, raising the temperature and dissipating the generated warmth from the inside out, promoting improved microcirculation. Spectral heat-storing fiber can absorb all regions of the solar spectrum, including visible and invisible light. When combined with nylon filaments to form core-spun yarn, it increases the absorption of light by the core-spun yarn, further enhancing the heat storage effect.

[0023] The present invention further provides a method for preparing the core-spun yarn as described above, comprising the following steps:

[0024] The nylon filament was used as the inner core layer and the heat-retaining fiber was used as the outer skin layer for pretreatment.

[0025] The inner core layer is formed by combining and twisting multiple filaments to form the first yarn. The outer skin layer is then processed through a cotton cleaning process, a carding process, a drawing process, a roving process, and a spinning process to form a short fiber roving. After being drawn and refined, it forms the second yarn.

[0026] The first yarn and the second yarn are together drawn and twisted to form the core-spun yarn.

[0027] According to some preferred embodiments of the present invention, a post-processing method is also included, wherein the post-processing method is to clean the core-spun yarn and then adsorb the phase change microcapsules onto the surface of the outer skin layer of the core-spun yarn by padding.

[0028] Specifically, the core-spun yarn is subjected to standard soap washing to ensure its surface is clean; then, the phase change nucleus (such as polyethylene glycol) is mixed with a crosslinking agent (such as N,N'-methylenebisacrylamide) and subjected to free radical polymerization in a raw material suspension (such as methacrylic acid suspension) to encapsulate the phase change nucleus in polymethacrylic acid to obtain phase change microcapsules; the phase change microcapsules are impregnated into the core-spun yarn, so that the phase change microcapsules are physically adsorbed onto the outer skin layer of the core-spun yarn; finally, curing is performed to ensure a tight bond between the phase change microcapsules and the core-spun yarn, improving the durability of the phase change microcapsule function, and then the auxiliaries and impurities involved in the reaction are removed. The final weight gain of the core-spun yarn with attached phase change microcapsules is 7% to 9%.

[0029] Another object of the present invention is to provide a heat-retaining and warm fabric having core-spun yarn as described above.

[0030] According to some preferred embodiments of the present invention, the fabric comprises a surface layer and an inner layer that are bonded together, both of which are prepared from the core-spun yarn through warp and weft weaving. The surface layer has a honeycomb weave structure, and the inner layer has a twill weave structure. The warp density of both the surface and inner layers is 240–280 threads / 10cm, and the weft density is 200–240 threads / 10cm.

[0031] The present invention also provides a method for preparing the heat-retaining and warm-insulating fabric as described above, comprising the following steps:

[0032] Using the core-spun yarn as the warp and weft yarns, the warp and weft yarns are interwoven to obtain the outer transition layer and the inner layer, respectively;

[0033] The light-absorbing material is adhered to the surface transition layer by coating or impregnation, and then dried and cured to obtain the surface layer. Specifically, the coating method involves: first, pre-treating the surface transition layer to remove impurities and stains to ensure the light-absorbing material adheres firmly; then, mixing the light-absorbing material with adhesive, wetting agent, and dispersant, and applying it to the surface transition layer by roller coating or spraying; finally, curing, cleaning, and drying to obtain the final surface layer. The impregnation method involves: immersing the surface transition layer in a solution containing the light-absorbing material; squeezing out excess solution using rollers to ensure the light-absorbing material adheres evenly to the surface transition layer; and then drying and curing to ensure the strong bond between the light-absorbing material and the fabric, thus obtaining the surface layer.

[0034] The outer layer and the inner layer are connected by sewing or bonding to obtain the fabric.

[0035] In some embodiments of the present invention, the surface layer adopts a honeycomb structure. Utilizing the characteristics of its uneven structure, it is easy to fill the recessed parts of the honeycomb structure with light-absorbing material, further improving its absorption of external heat. The inner layer adopts a twill weave structure, which can improve the reflection of heat emitted by the human body, thereby achieving efficient heat storage and insulation.

[0036] Compared with existing technologies, the advantages of this invention due to the adoption of the above technical solutions are as follows: The nylon filament, core-spun yarn, heat-retaining and warm fabric, and their preparation method of this invention, by designing cavities inside the shell of the nylon filament to store air, prevents the complete loss of static air when the nylon filament is compressed, thus preserving it for longer and improving its heat storage performance. Furthermore, the nylon filament is core-spun and composited with other heat-retaining fibers to obtain a core-spun fabric with stronger heat storage effect. Phase change microcapsules are then coated on the surface of the outer layer to enhance the absorption of light and heat. Finally, the core-spun yarn with phase change microcapsules is woven to obtain the outer and inner layers of the fabric. The outer layer adopts a honeycomb structure, with light-absorbing material filling the recesses to further improve the absorption of external heat. Finally, connecting the outer and inner layers yields a fabric with enhanced heat storage function. The fabric has only two layers, and both the warp and weft yarns of the outer and inner layers are nylon filaments with hollow structures, effectively reducing fabric weight and improving wearing comfort. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1This is a three-dimensional structural diagram of the nylon filament in Embodiment 1 of the present invention;

[0039] Figure 2 This is a schematic diagram of the front view of the cross-section of the nylon filament in Embodiment 1 of the present invention;

[0040] Figure 3 This is a three-dimensional structural diagram of the core-spun yarn in Embodiment 3 of the present invention;

[0041] Figure 4 This is an exploded view of the heat-retaining and warming fabric in Embodiment 4 of the present invention;

[0042] Figure 5 This is a schematic diagram of the surface structure of the heat-retaining and warm-keeping fabric in Embodiment 4 of the present invention;

[0043] Figure 6 This is a schematic diagram of the inner layer structure of the heat-retaining and warm-insulating fabric in Embodiment 4 of the present invention;

[0044] The attached figures are labeled as follows:

[0045] Nylon filament-10, shell body-11, first column-12, connecting part-13, cavity-2, cavity petal-21, spacer-22, core-spun yarn-20, heat storage fiber-3, phase change microcapsule-4, fabric-30, outer layer-5, inner layer-6. Detailed Implementation

[0046] 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 described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0047] This invention provides a heat-retaining and warm fabric, comprising an outer layer 5 and an inner layer 6 bonded together. Both the outer layer 5 and the inner layer 6 include warp and weft yarns, with a warp density of 240-280 threads / 10cm and a weft density of 200-240 threads / 10cm. The outer layer 5 has a honeycomb weave structure, with the recessed portions of the honeycomb filled with light-absorbing material to further enhance its absorption of external heat. The inner layer 6 has a twill weave structure, which improves the reflection of heat emitted by the human body, thereby achieving efficient heat retention and warmth. The outer layer 5 and the inner layer 6 can be connected by sewing or bonding.

[0048] Furthermore, the warp and weft yarns of the outer layer 5 and the inner layer 6 are both core-spun yarns 20 with a fineness of 14-18 tex. The core-spun yarn 20 includes an inner core layer and an outer sheath layer wrapped around the inner core layer. The inner core layer includes multiple nylon filaments 10, and the outer sheath layer includes multiple heat-retaining fibers 3. The heat-retaining fibers 3 are volcanic rock heat-retaining fibers or spectral heat-retaining fibers. The mass percentage of the nylon filaments 10 in the core-spun yarn 20 is 60%-70%. Specifically, the nylon filaments 10 include a shell and a cavity 2 located inside the shell. The cavity 2 is used to store air, and the length of the cavity 2 is equal to the length of the shell. Cavity 2 includes multiple spaced-apart cavity units; the shell includes a shell body 11, a first column 12, and a connecting part 13 located between two adjacent cavity units. The connecting part 13 is used to connect the first column 12 and the shell body 11. The multiple cavity units are arranged circumferentially along the first column 12, and the center of the first column 12 coincides with the center of the nylon filament 10. The area of ​​cavity 2 in the cross-section of the nylon filament 10 accounts for 20% to 30%.

[0049] Each cavity unit includes a plurality of spaced cavity petals 21. The length of at least one cavity petal 21 in each cavity unit is greater than the length of the remaining cavity petals 21. The reason why at least one cavity petal 21 in each cavity unit is the longest in this invention is that when designing a spinneret that matches the cross-sectional shape of the nylon filament 10, if the part of the spinneret used to form the cavity 2 is completely hollowed out, the middle part of the spinneret cannot be fixed. Therefore, at least one longest plate is provided in the part of the spinneret that forms each cavity unit to be fixed to the annular outer edge of the spinneret.

[0050] Furthermore, the width of each cavity petal 21 gradually increases from one end near the center of the nylon filament 10 to the other. Each cavity unit has a spacer 22 between adjacent cavity petals 21. One end of the spacer 22 is connected to the housing body 11, and the other end extends towards the first column 12. This arrangement ensures that the ends of the multiple cavity petals 21 near the center of the nylon filament 10 in each cavity unit are connected to each other, while the ends of the multiple cavity petals 21 away from the center of the nylon filament 10 are spaced apart. This configuration makes the structure of each cavity petal 21 more stable, resulting in less deformation under compression and retaining more residual still air, thereby improving the heat storage performance of the nylon filament 10.

[0051] Furthermore, the outer surface of the outer skin layer is also coated with phase change microcapsules 4. The phase change microcapsules 4 include a phase change core and a shell for encapsulating the phase change core. The phase change core is made of one or more of paraffin wax, fatty acids, and fatty alcohols, while the shell is made of one or more of polyurethane, polymethyl methacrylate, and urea-formaldehyde resin. Utilizing the phase change core in the phase change microcapsules 4 to absorb and release heat through phase change, achieving photothermal conversion for energy storage, is beneficial for improving the heat storage and insulation properties of the core-spun yarn 20.

[0052] This invention also provides a method for preparing a heat-retaining and warm fabric, comprising the following steps:

[0053] Step 1: Preparation of modified nylon melt

[0054] Modified nylon melt is prepared by melting nylon chips and then performing copolymerization, surface crosslinking, or enzyme modification. The modified nylon melt is then added to a solvent and mixed evenly to obtain a modified nylon melt solution. The thermal conductivity of the modified nylon is 0.128–0.151 W / (m·℃).

[0055] Step 2: Prepare 10 nylon filaments

[0056] First, a spinneret is designed and processed according to the cross-sectional shape of nylon filament 10. Then, a light-absorbing material with a particle size of 50-100 nm is added to the modified nylon melt solution in step 1. After stirring for 15-45 min, it is ultrasonically dispersed for 15-45 min. Finally, after centrifugation and sedimentation, the upper dispersion is collected and mixed with water and a molecular weight regulator to obtain a spinning solution. The mass ratio of modified nylon melt to heat storage accelerator in the spinning solution is 95-99:1. The spinning solution is extruded through the spinneret to form a filament bundle. The spinning temperature is 270-320℃ and the spinning speed is 800-1300 m / min. Then, the nylon filament 10 is obtained through monomer suction, side blowing cooling, bundling and oiling, stretching and setting, network interlacing and winding. The stretching and setting temperature is 75-90℃, and the fineness of the stretched yarn is 70-90D. The winding speed is 4500-5000 m / min.

[0057] Step 3: Prepare 20 core-spun yarns

[0058] The nylon filament 10 and the heat-storing fiber 3 are pretreated to clean surface impurities and dirt. The nylon filament 10 is used as the inner core layer and the volcanic rock heat-storing fiber is used as the outer sheath layer. The inner core layer is multi-filament combined and twisted to form an elastic ply, which is the first yarn. The outer sheath layer is processed through cotton cleaning, carding, drawing, roving and spinning processes to form a short fiber roving. After drafting and refining, the second yarn is obtained. Then, using the Selofair spinning technology, the first yarn is fed directly into the front roller without being drafted by the spinning machine. The second yarn is also fed into the front roller. After passing through the tension device and yarn guide, the two yarns undergo normal drafting and sliver compounding at the convergence point, and are finally twisted to form a core-spun yarn 20. The core-spun yarn 20 is then subjected to standard soap washing to ensure its surface is clean and ready for use.

[0059] A phase change core (such as polyethylene glycol) is mixed with a crosslinking agent (such as N,N'-methylenebisacrylamide) and subjected to free radical polymerization in a raw material suspension to obtain phase change microcapsules 4. The phase change microcapsules 4 are then impregnated into cleaned core-spun yarn 20, allowing them to physically adhere to the outer layer of the yarn. Finally, curing is performed to ensure a tight bond between the phase change microcapsules 4 and the core-spun yarn 20, improving the durability of the phase change microcapsule function. After removing the reactants and impurities, core-spun yarn 20 with phase change microcapsules 4 attached to its outer layer is obtained. The final weight gain of the core-spun yarn 20 with attached phase change microcapsules 4 is 7%–9%. The nylon filaments 10 in the core-spun yarn 20 account for 60%–70% of the total mass.

[0060] Step 4: Weaving

[0061] The core-spun yarn 20 with phase change microcapsules 4 attached to the outer skin layer obtained in step 3 is used as the warp and weft yarns, respectively. The warp yarn is passed through yarn cones, warping, sizing, and threading, and then tightly interwoven with the weft yarn to obtain a honeycomb structure outer transition layer and a twill structure inner layer 6, respectively. Light-absorbing material is attached to the outer transition layer by coating or impregnation, and after drying and curing, the outer layer 5 is obtained. Finally, the outer layer 5 and the inner layer 6 are connected by bonding or sewing to obtain a heat-retaining and warm fabric 30.

[0062] The light-absorbing material is one or more of the following: nano-ceramic particles, graphene, carbon nanotubes, carbon black, carbon dots, MXene, zirconium carbide, and silicon carbide.

[0063] Example 1: Nylon Filament

[0064] This embodiment of a nylon filament 10 includes a shell and a cavity 2 located inside the shell. The cavity 2 is used to store air, and its length is equal to the length of the shell. The cavity 2 includes multiple spaced-apart cavity units. The shell includes a shell body 11, a first column 12, and a connecting portion 13 located between two adjacent cavity units. The connecting portion 13 is used to connect the first column 12 and the shell body 11. The multiple cavity units are arranged circumferentially along the first column 12, and the center of the first column 12 coincides with the center of the nylon filament 10. The area of ​​the cavity 2 in the cross-section of the nylon filament 10 accounts for 25%.

[0065] Each cavity unit includes multiple spaced-apart cavity lobes 21, and the width of at least one cavity lobe 21 in each cavity unit is greater than the width of the remaining cavity lobes 21. Specifically, in this embodiment, as shown... Figure 1 and Figure 2 As shown, cavity 2 includes four cavity units, each cavity unit including three spaced-apart cavity petals 21. A spacer 22 is provided between adjacent cavity petals 21 in each cavity unit. One end of the spacer 22 is connected to the housing body 11, and the other end extends towards the first column 12. Furthermore, the width of each cavity petal 21 gradually increases from one end near the center of the nylon filament 10 to the other end, making the structure of each cavity petal 21 more stable. When compressed, its deformation is smaller, and more residual still air is retained, thereby improving the heat storage performance of the nylon filament 10.

[0066] In this embodiment, each cavity unit includes a cavity main lobe and cavity auxiliary lobes symmetrically arranged on both sides of the cavity main lobe. The length of the cavity main lobe is greater than the length of the cavity auxiliary lobe. Both the cavity main lobe and the cavity auxiliary lobe are cavity lobes 21.

[0067] Example 2: Preparation method of nylon filament

[0068] First, ethylene glycol is esterified under excess oxalic acid at 240℃ for 3 hours to obtain carboxyl-terminated polyester. Then, nylon chips are added, and the temperature is raised to 260℃, molten to allow the hydroxyl groups in the nylon melt to undergo esterification grafting with the carboxyl groups of the polyester, resulting in modified nylon melt. Nano-alumina with a particle size of 55nm is added to the modified nylon melt, stirred for 15 minutes, then ultrasonically dispersed for 30 minutes. Finally, after centrifugation for 5 minutes, the supernatant dispersion is collected and mixed with water and maleic acid (molecular weight regulator) until homogeneous to obtain a spinning solution. The mass ratio of modified nylon melt to heat storage accelerator in the spinning solution is 99:1. The purpose of adding the molecular weight regulator is to adjust and control the molecular weight of the nylon polymer, ensuring the spinning solution has a suitable viscosity for spinning. The spinning solution is extruded through a spinneret after extrusion to form a filament bundle. The spinning temperature is 300℃ and the spinning speed is 1300m / min. The filament bundle is then subjected to monomer suction, side-blowing cooling, bundling and oiling, stretching and setting, web interlacing, and winding to obtain nylon filament 10. The stretching and setting is performed at 85℃, and in this embodiment, the fineness of the stretched yarn is 80D; the winding speed is 4800m / min.

[0069] In this embodiment, nylon 6 is preferred as the nylon chip. The original thermal conductivity of the nylon is reduced by modifying it to improve its warmth retention. The thermal conductivity of the modified nylon is 0.149 W / (m·℃).

[0070] Example 3: Heat-retaining and warm fabric

[0071] This embodiment provides a heat-retaining and warm fabric, such as... Figure 4 As shown, it includes an outer layer 5 and an inner layer 6 that are bonded together. Both the outer layer 5 and the inner layer 6 include warp yarns and weft yarns, with a warp yarn density of 260 threads / 10cm and a weft yarn density of 220 threads / 10cm; Figure 5 As shown, the surface layer 5 has a honeycomb structure, with the recessed parts filled with light-absorbing material to further enhance its absorption of external heat. Figure 6 As shown, the inner layer 6 has a twill weave structure, which can improve the reflection of heat emitted by the human body, thereby achieving efficient heat storage and warmth retention; the outer layer 5 and the inner layer 6 can be connected by sewing or bonding.

[0072] Furthermore, both the warp and weft yarns of the outer layer 5 and the inner layer 6 are core-spun yarns 20 with a fineness of 16 tex, such as... Figure 3As shown, the core-spun yarn 20 includes an inner core layer and an outer sheath layer wrapping around the inner core layer. The inner core layer includes multiple nylon filaments 10 as described in Example 1, and the outer sheath layer includes multiple heat-retaining fibers 3. The heat-retaining fibers 3 are volcanic rock heat-retaining fibers or spectral heat-retaining fibers. The nylon filaments 10 in the core-spun yarn 20 account for 60% of the total mass.

[0073] Furthermore, the outer surface of the outer skin layer is also coated with phase change microcapsules 4. The phase change microcapsules 4 include a phase change core and a shell for encapsulating the phase change core. The phase change core is made of one or more of paraffin wax, fatty acids, and fatty alcohols, while the shell is made of one or more of polyurethane, polymethyl methacrylate, and urea-formaldehyde resin. Utilizing the phase change core in the phase change microcapsules 4 to absorb and release heat through phase change, achieving photothermal conversion for energy storage, is beneficial for improving the heat storage and insulation properties of the core-spun yarn 20.

[0074] Example 4: Preparation method of heat-retaining and warm fabric

[0075] Step 1: Preparation of modified nylon melt

[0076] Ethylene glycol was esterified in excess oxalic acid at 240°C for 3 hours to obtain carboxyl-terminated polyester. Nylon 6 chips were then added, and the temperature was further increased to 260°C, molten the nylon 6 chips. The hydroxyl groups in the nylon melt and the carboxyl groups on the polyester underwent esterification grafting to prepare modified nylon melt. In this embodiment, nylon 6 chips were preferred. Modification of the nylon reduced its original thermal conductivity, improving its warmth retention. The resulting modified nylon had a thermal conductivity of 0.149 W / (m·°C).

[0077] Step 2: Prepare 10 nylon filaments

[0078] First, a spinneret was designed and processed according to the cross-sectional shape of the target nylon filament 10. Then, nano-alumina with a particle size of 55 nm was added to the modified nylon melt solution in step 1. After stirring for 15 min, it was ultrasonically dispersed for 30 min. Finally, after centrifugation and sedimentation for 5 min, the upper dispersion was collected and mixed with water and maleic acid to obtain a spinning solution. The mass ratio of modified nylon melt to heat storage accelerator in the spinning solution was 99:1. The spinning solution was extruded from the spinneret to form a filament bundle after extrusion. The spinning temperature was 300℃ and the spinning speed was 1300 m / min. Then, the nylon filament 10 was obtained through monomer suction, side blowing cooling, bundling and oiling, stretching and setting, network entanglement and winding. The stretching and setting temperature was 85℃, the fineness of the stretched yarn was 80D, and the winding speed was 4800 m / min.

[0079] Step 3: Prepare 20 core-spun yarns

[0080] Nylon filament 10 and volcanic rock heat storage fiber are pretreated to remove surface impurities and dirt. Using nylon filament 10 as the inner core layer and volcanic rock heat storage fiber as the outer sheath layer, the inner core layer is multi-filament combined and twisted to form elastic strands, resulting in the first yarn. The outer sheath layer undergoes cotton cleaning, carding, drawing, roving, and spinning processes to form short-fiber roving, which is then drafted and refined to obtain the second yarn. Using Selofair spinning technology, the first yarn is fed directly into the front roller without being drafted on a spinning machine, and the second yarn is also fed into the front roller. After passing through a tension device and yarn guide, both yarns undergo normal drafting and sliver compounding at the convergence point, and are finally twisted to form core-spun yarn 20 with a fineness of 16 tex. The core-spun yarn 20 is then subjected to standard soaping to ensure its surface cleanliness and is ready for use.

[0081] Polyethylene glycol and N,N'-methylenebisacrylamide were mixed and subjected to free radical polymerization in a methacrylic acid suspension to encapsulate the phase change core in polymethacrylic acid, resulting in phase change microcapsules 4. The phase change microcapsules 4 were then impregnated into cleaned core-spun yarn 20, allowing them to physically adhere to the outer layer of the yarn. Curing was then performed to ensure a tight bond between the phase change microcapsules 4 and the core-spun yarn 20, improving the durability of the phase change microcapsule function. After removing the reactants and impurities, core-spun yarn 20 with phase change microcapsules 4 attached to its outer layer was obtained. The final weight gain of the core-spun yarn 20 with attached phase change microcapsules 4 was 7.94%. The nylon filaments 10 in the core-spun yarn 20 accounted for 60% of the total mass.

[0082] Step 4: Weaving

[0083] The core-spun yarn 20 with phase change microcapsules 4 attached to the outer skin layer obtained in step 3 is used as the warp and weft yarns, respectively. The density of the warp yarn is 260 threads / 10cm, and the density of the weft yarn is 220 threads / 10cm. After the warp yarn is processed through cone spinning, warping, sizing, and threading, it is tightly interwoven with the weft yarn to obtain the honeycomb structure outer transition layer and the twill structure inner layer 6, respectively. The outer transition layer is then immersed in a solution containing graphene, and the excess solution is squeezed out by rollers to make the graphene evenly adhere to the outer transition layer. After drying and curing, the outer layer 5 is obtained. Finally, the outer layer 5 and the inner layer 6 are connected by stitching to obtain the heat-retaining and warm fabric 30.

[0084] In this embodiment, the fabric 30 was tested according to the methods in GB / T 18319-2019 "Test Method for Photothermal Storage Performance of Textiles" and GB / T 30127-2013 "Test and Evaluation of Far-Infrared Performance of Textiles". The maximum temperature rise was measured to be 7.2℃, the average temperature rise was 4.8℃, the far-infrared emissivity was 0.97, and the far-infrared radiation temperature rise was 2.5℃. Simultaneously, the thermal resistance of fabric 30 was measured to be 1.235m using the evaporative hot plate method. 2 K / W, insulation rate 45%.

[0085] Comparative Example 1: Fabric Preparation Method

[0086] The difference between Comparative Example 1 and Example 4 is that the nylon melt used to prepare nylon filament in Comparative Example 1 was not modified. During spinning, nano-alumina with a particle size of 55nm was directly added to the nylon 6 solution, stirred and ultrasonically dispersed, and centrifuged to obtain the spinning solution. The nylon filament was then obtained by spinning through a customized spinneret. All other steps were the same.

[0087] The fabric prepared in this comparative example was tested according to the methods in GB / T 18319-2019 "Test Method for Photothermal Storage Performance of Textiles" and GB / T 30127-2013 "Test and Evaluation of Far-Infrared Performance of Textiles". The maximum temperature rise was 6.8℃, the average temperature rise was 4.5℃, the far-infrared emissivity was 0.92, and the far-infrared radiation temperature rise was 2.3℃. The thermal resistance of the fabric was measured to be 1.227 μm using the evaporative hot plate method. 2 K / W, insulation rate 42%.

[0088] Comparative Example 2: Fabric Preparation Method

[0089] The difference between Comparative Example 2 and Example 4 is that in Comparative Example 2, when preparing nylon filament, the spinneret is a conventional spinneret, so that the nylon filament obtained by spinning does not include cavity 2 and has a solid internal structure; the other steps are the same.

[0090] The fabric prepared in this comparative example was tested according to the methods in GB / T 18319-2019 "Test Method for Photothermal Storage Performance of Textiles" and GB / T 30127-2013 "Test and Evaluation of Far-Infrared Performance of Textiles". The maximum temperature rise was 6.0℃, the average temperature rise was 4.3℃, the far-infrared emissivity was 0.89, and the far-infrared radiation temperature rise was 1.5℃. The thermal resistance of the fabric was measured to be 1.024 μm using the evaporative hot plate method. 2 K / W, insulation rate 35%.

[0091] Comparative Example 3: Fabric Preparation Method

[0092] The difference between Comparative Example 3 and Example 4 is that in Comparative Example 3, after the core-spun yarn was prepared, no post-treatment was performed on the core-spun yarn, that is, the surface of the outer skin layer of the core-spun yarn was not attached with phase change microcapsules 4; the other steps were the same.

[0093] The fabric prepared in this comparative example was tested according to the methods in GB / T 18319-2019 "Test Method for Photothermal Storage Performance of Textiles" and GB / T 30127-2013 "Test and Evaluation of Far-Infrared Performance of Textiles". The maximum temperature rise was 6.4℃, the average temperature rise was 4.5℃, the far-infrared emissivity was 0.92, and the far-infrared radiation temperature rise was 2.2℃. The thermal resistance of the fabric was measured to be 1.186m using the evaporative hot plate method. 2 • K / W, insulation rate 39%.

[0094] Comparative Example 4: Fabric Preparation Method

[0095] The difference between Comparative Example 4 and Example 4 is that the surface transition layer obtained by weaving in Comparative Example 4 is directly used as the surface layer and the inner layer for sewing, without immersing the surface transition layer in a solution of light-absorbing material; the other steps are the same.

[0096] The fabric prepared in this comparative example was tested according to the methods in GB / T 18319-2019 "Test Method for Photothermal Storage Performance of Textiles" and GB / T 30127-2013 "Test and Evaluation of Far-Infrared Performance of Textiles". The maximum temperature rise was 6.7℃, the average temperature rise was 4.6℃, the far-infrared emissivity was 0.95, and the far-infrared radiation temperature rise was 2.3℃. The thermal resistance of the fabric was measured to be 1.189 μm using the evaporative hot plate method. 2 • K / W, insulation rate 40%.

[0097] Results and Discussion:

[0098] The test data from Example 4 and Comparative Examples 1 to 4 show that the fabric 30 prepared in Example 4 has the best heat storage and insulation performance, with the highest maximum temperature rise, average temperature rise, far-infrared emissivity, far-infrared radiation temperature rise, thermal resistance, and insulation rate. Among Comparative Examples 1 to 4, Comparative Example 2 has the worst data because the nylon filament does not have an internal cavity 2. This demonstrates that the cavity 2 inside the shell of the nylon filament 10 of the present invention plays a key role in improving the heat storage performance of the fabric. The cavity 2 prevents the complete loss of static air and allows it to be retained for a longer period, thus improving heat storage and insulation performance. The test data from Comparative Examples 1, 3, and 4 indicate that the modification of the nylon, the phase change microcapsules 4 on the outer layer of the core-spun yarn, and the light-absorbing material on the surface layer 5 of the fabric 30 can all improve the heat storage performance of the fabric 30 to varying degrees.

[0099] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A nylon filament, characterized in that, The device includes a shell and a cavity located inside the shell. The cavity comprises multiple spaced-apart cavity units. The shell includes a shell body, a first column, and a connecting portion between two adjacent cavity units. The connecting portion connects the first column to the shell body. The multiple cavity units are arranged circumferentially along the first column, and the center of the first column coincides with the center of the nylon filament. The area of ​​the cavity in the cross-section of the nylon filament accounts for 20% to 30%, and the length of the cavity is equal to the length of the shell. The cavity is used to store air. Each cavity unit includes a plurality of spaced-apart cavity lobes, and the length of at least one cavity lobe in each cavity unit is greater than the length of the remaining cavity lobes.

2. The nylon filament according to claim 1, characterized in that, The width of each cavity flap gradually increases from one end near the center of the nylon filament to the other end.

3. The nylon filament according to claim 2, characterized in that, The multiple cavity petals in each cavity unit are connected to each other at the ends near the center of the nylon filament, and the multiple cavity petals in each cavity unit are spaced apart at the ends away from the center of the nylon filament.

4. The nylon filament according to claim 3, characterized in that, Each cavity unit has a spacer between two adjacent cavity lobes, one end of which is connected to the housing body, and the other end of which extends toward the first column.

5. A method for preparing nylon filament as described in any one of claims 1-4, characterized in that, Includes the following steps: The nylon filament is obtained by mixing a heat storage promoter with a solution containing modified nylon and then spinning it; the thermal conductivity of the modified nylon is 0.128~0.151W / (m·℃).

6. The preparation method according to claim 5, characterized in that, The solution containing modified nylon is a modified nylon melt solution obtained by adding modified nylon melt to a solvent and mixing it evenly; the modified nylon melt is prepared by melting nylon chips and then copolymerizing, surface crosslinking or enzyme modification.

7. The preparation method according to claim 6, characterized in that, The method of spinning by mixing the heat storage accelerator with a solution containing modified nylon is as follows: the heat storage accelerator is added to the modified nylon melt solution and mixed evenly to obtain a mixed spinning solution. The spinning solution is extruded from a spinneret after extrusion to form a filament bundle. Then, the filament bundle is subjected to monomer suction, side blowing cooling, bundling and oiling, stretching and setting, network entanglement, and winding to obtain the nylon filament. The mass ratio of the modified nylon melt to the heat storage accelerator in the spinning solution is 95~99:

1.

8. The preparation method according to claim 5, characterized in that, The heat storage promoter includes a light-absorbing material, which is one or more of graphene, carbon nanotubes, carbon black, carbon dots, MXene, zirconium carbide, and silicon carbide.

9. A core-spun yarn, characterized in that, It includes an inner core layer and an outer skin layer wrapped around the inner core layer. The inner core layer includes multiple nylon filaments as described in any one of claims 1-4, and the outer skin layer includes multiple heat-storing fibers. The outer surface of the outer skin layer is also attached with phase change microcapsules.

10. The core-spun yarn according to claim 9, characterized in that, The nylon filaments in the core-spun yarn account for 60% to 70% of the total mass.

11. The core-spun yarn according to claim 9, characterized in that, The phase change microcapsule includes a phase change core and a shell for encapsulating the phase change core. The phase change core is made of one or more of paraffin, fatty acids, and fatty alcohols.

12. The core-spun yarn according to claim 9, characterized in that, The heat storage fiber is a volcanic rock heat storage fiber or a spectral heat fiber.

13. A method for preparing core-spun yarn as described in any one of claims 9-12, characterized in that, Includes the following steps: The nylon filament was used as the inner core layer and the heat-retaining fiber was used as the outer skin layer for pretreatment. The inner core layer is formed by combining and twisting multiple filaments to form the first yarn, and the outer skin layer is processed to form short fiber roving, which is then stretched and refined to form the second yarn. The first yarn and the second yarn are together drawn and twisted to form the core-spun yarn.

14. The preparation method according to claim 13, characterized in that, It also includes post-processing, the post-processing method being: after cleaning the core-spun yarn, the phase change microcapsules are adsorbed onto the surface of the outer skin layer of the core-spun yarn by padding.

15. A heat-retaining and warm-insulating fabric, characterized in that, The fabric has a core-spun yarn as described in any one of claims 9-12.

16. A heat-retaining and warm-insulating fabric as described in claim 15, characterized in that, It includes an outer layer and an inner layer that are bonded together, both of which are prepared by interlacing the core-spun yarn through warp and weft. The outer layer has a honeycomb structure.

17. A method for preparing a heat-retaining and warm-insulating fabric as described in claim 15 or 16, characterized in that, Includes the following steps: Using the core-spun yarn as the warp and weft yarns, the warp and weft yarns are interwoven to obtain the outer transition layer and the inner layer, respectively; The light-absorbing material is adhered to the surface transition layer by coating or impregnation, and the surface layer is obtained after drying and curing. The outer layer and the inner layer are connected to obtain the fabric.

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