Preparation method of functional fabric and backpack assembled by functional fabric

Abstract

The invention discloses a preparation method of a functional fabric and a knapsack assembled by the functional fabric, and belongs to the technical field of fabric preparation. A flexible continuous interface is constructed through PA latex, Cu2O antibacterial particles form a semi-embedded fixed structure, composite optical microspheres can be stably attached and orderly assembled, and the attachment firmness and surface functional activity of a functional layer are considered; through evaporation-induced self-assembly of the monodisperse composite optical microspheres, a periodic microstructure is formed on the surface of the fabric, so that a stable structural color is generated; a DA3261-dopamine conjugate and TPU are compounded and subjected to ultraviolet polymerization to form a temperature-sensitive layer, so that the outer surface of the knapsack has visual thermal response capability, the temperature-sensitive layer starts to have obvious color change at 35 DEG C and turns from bluish violet to amaranth at 40 DEG C, the comprehensive chromatic aberration delta E reaches 28.7, the delta E exceeds 30 at 45 DEG C or above, and the knapsack shows remarkable temperature early warning capability.

Description

Technical Field

[0001] This invention discloses a fabric preparation technology, and in particular relates to a method for preparing a functional fabric and a backpack assembled from it. Background Technology

[0002] Current backpack shell fabrics are mostly made of ordinary polyester, nylon, canvas, or their coated composite materials. These typically only offer abrasion resistance, water repellency, or a certain level of strength retention, making it difficult to simultaneously achieve aesthetic appeal, thermal insulation, hygiene protection, and environmental responsiveness. Especially in scenarios involving the storage of high-value items such as computers, medicines, food, and photographic equipment, traditional backpack fabrics suffer from the following problems:

[0003] Firstly, the fabric has a single function and lacks comprehensive protection against strong light, high temperature and bacterial contamination.

[0004] Secondly, the appearance mainly depends on dyeing and finishing, which limits the color range and makes it prone to fading.

[0005] Third, it has insufficient ability to suppress temperature rise under long-term sun exposure;

[0006] Fourth, multifunctional coatings often use simple blending or single-sided stacking methods, which can easily lead to mutual interference between functional layers, poor adhesion, particle shedding, and performance degradation.

[0007] Fifth, most existing backpack fabrics cannot provide visual feedback on temperature anomalies, making it difficult for users to perceive the heat accumulation on the bag's surface in a timely manner. Summary of the Invention

[0008] The purpose of this invention is to provide a method for preparing a functional fabric and a backpack assembled from it in order to solve the above-mentioned problems.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a functional fabric, comprising the following steps:

[0010] S1, double-layer jacquard base fabric is prepared by using fully dull polyester filament as the surface warp yarn, black polyester yarn as the interlayer weft yarn, and silver-plated polyester yarn as the partial reflective yarn. The base fabric is woven with a double-layer jacquard structure. The surface layer is a 5 / 1 right twill and partial satin composite jacquard structure, and the inner layer is a high-density structure. The two layers are connected by a joint structure.

[0011] S2, Light-blocking and heat-insulating layer construction: A light-blocking and heat-insulating layer is introduced into the middle layer, back layer, or interlayer interface of the double-layer jacquard base fabric. The light-blocking and heat-insulating layer includes a black light-absorbing component, a metallized reflective component, and a fully dull cross-section fiber component. The black light-absorbing component is 150D black low-elastic heavy-duty yarn, the metallized reflective component is silver-plated polyester fiber, and the fully dull cross-section fiber component is W-shaped cross-section fully dull polyester filament. Among them, the 150D black low-elastic heavy-duty yarn is set as the main light-blocking weft yarn in the light-blocking area in the middle of the fabric, the silver-plated polyester fiber is set in the reflection enhancement area near the light-receiving side, and the W-shaped cross-section fully dull polyester filament is set on the surface layer of the fabric to form a composite light-blocking jacquard fabric.

[0012] S3, PA latex preparation: 1L of deionized water was used as solvent, nitrogen was purged to remove oxygen, 50g of methyl methacrylate, 50g of butyl acrylate and 5g of sodium dodecylbenzene sulfonate (SDBS) were added, and the mixture was stirred evenly with magnetic stirring and heated to 80℃. 3g of potassium sulfate was dissolved in 100ml of deionized water and added. The mixture was stirred and reacted for 5h under a nitrogen atmosphere to obtain PA latex.

[0013] S4, Preparation of Cu2O antibacterial particles: Weigh 15g polyvinylpyrrolidone (PVP), 5.5g sodium citrate dihydrate and 5.2g copper acetate monohydrate, add 300ml ethylene glycol and 1L deionized water in sequence, stir magnetically for 20min and sonicate for 20min, then add 200ml of 0.4mol / L NaOH solution, and add a total of 150mL of 0.2mol / L ascorbic acid solution in two steps, stir for 60min, centrifuge for 10min, wash and freeze-dry for 5h, disperse 0.5g of freeze-dried powder in 100mL anhydrous ethanol to obtain a dispersion containing Cu2O antibacterial particles;

[0014] S5, Antibacterial layer construction: The composite light-blocking jacquard fabric is immersed in a 50% ethanol solution and ultrasonically washed for 3 hours. After drying, it is cut into pieces and then sprayed with PA latex emulsion on the inside of the fabric and dried. Then, 50-300 μl of Cu2O antibacterial particle dispersion is sprayed and dried at 60℃ for 15 minutes. The Cu2O antibacterial particles are embedded in the PA latex to form the PA layer.

[0015] S6, Preparation of composite optical microspheres: 5g ammonium bicarbonate and 1L deionized water were purged with nitrogen for 10 min, then 190g styrene, 10g methyl methacrylate and 10g acrylic acid were added, along with 70mg-150mg sodium dodecylbenzenesulfonate (SDBS). The mixture was pre-emulsified at 75℃ and 350rpm for 1.5h, then 200mL of an aqueous solution containing 3.6g ammonium persulfate was added to initiate the reaction for 4h, followed by aging at 80℃ for 2h to obtain a monodisperse composite optical microsphere dispersion.

[0016] S7, Color development layer construction: PA latex emulsion is pre-coated on the outer surface of the fabric, and then monodisperse composite optical microsphere dispersion is coated onto the same surface using a scraper at a speed of 1 cm / s. After drying, a fabric with a color development layer is obtained.

[0017] S8, Composite Finishing, involves hot-pressing the fabric with a 210D nylon lining to obtain a functional fabric.

[0018] Preferably, the functional fabric also includes a temperature-sensitive early warning functional layer, the preparation of which includes the following steps:

[0019] K1, DA3261-dopamine conjugate synthesis: 10g of 10,12-pentacarbazide diacetic acid (DA3261) was dissolved in 200ml of dichloromethane, filtered to remove polymerized impurities, and rotary evaporated to obtain pure DA3261; 1.8g of DA3261 and 0.138g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) were dissolved in 200ml of dichloromethane, and 0.82g of N-hydroxysuccinimide (NHS) was added. The reaction was carried out at 25℃ for 4h to obtain DA3261-NHS; then 1.5g of DA3261-NHS and 0.72g of dopamine were dissolved in 200ml of N,N-dimethylformamide (DMF), and 0.38g of triethylamine was added. The reaction was carried out at 25℃ under nitrogen for 12h with stirring to obtain DA3261-dopamine conjugate powder;

[0020] K2, Preparation of the temperature-sensitive layer: 10g TPU was added to 190g DMF and stirred at 45℃ until completely dissolved to obtain a 5% TPU solution; 50mg DA3261-dopamine coupling powder was added to 30mTPU solution, dissolved by ultrasonication, poured into a mold or locally coated on a predetermined area of ​​the fabric, dried at 80℃ to remove N,N-dimethylformamide DMF, and photopolymerized with 254nm ultraviolet light to form a DA3261-dopamine coupling / TPU temperature-sensitive layer.

[0021] An assembled backpack includes the following panels: front panel, back panel, side panel, bottom panel, flap, shoulder strap connector, and inner compartment. Some of the panels are assembled from functional fabrics prepared by the above-described method. The color-developing layer and temperature-sensitive layer of the functional fabric face the outside of the backpack, and the antibacterial layer of the functional fabric faces the inside of the backpack.

[0022] Preferably, the front panel and the flip cover are provided with a color-developing layer and a temperature-sensitive layer, the outer periphery of the inner compartment partition is provided with a light-shielding and heat-insulating enhancement area, and the inner compartment partition is set with the antibacterial layer facing inward.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] Through the synergistic design of double-layer jacquard base fabric with black light-absorbing components, metallized reflective components and fully matte irregular cross-section fiber components, a multi-optical path attenuation structure is constructed at the microscopic level to achieve the combined effects of light absorption, reflection and scattering, thereby significantly improving the light-shielding and heat insulation performance.

[0025] By constructing a flexible and continuous interface using PA latex, Cu2O antibacterial particles can form a semi-embedded fixed structure, enabling the composite optical microspheres to adhere stably and assemble in an orderly manner, thus balancing the adhesion strength of the functional layer with the surface functional activity.

[0026] By inducing self-assembly through evaporation of monodisperse composite optical microspheres, periodic microstructures are formed on the fabric surface, thereby generating stable structural colors;

[0027] A temperature-sensitive layer is formed by combining DA3261-dopamine coupling compound with TPU and then performing UV polymerization, giving the outer surface of the backpack a visible thermal response capability. The temperature-sensitive layer begins to show obvious color changes at 35℃, and changes from blue-purple to purplish-red at 40℃. The overall color difference ΔE reaches 28.7, and ΔE exceeds 30 above 45℃, showing a significant temperature warning capability.

[0028] By using a functional gradient assembly method of outer response, middle barrier, and inner protection, the resulting functional fabric is more suitable for the composite protection needs in backpack scenarios. Attached Figure Description

[0029] Figure 1 Chart showing the test results of the backpack's temperature-sensitive early warning performance;

[0030] Figure 2 Chart for early warning test of internal heat source in backpack;

[0031] Figure 3 The chart shows the test results of the backpack's antibacterial performance obtained using the oscillation method;

[0032] Figure 4 The chart shows the test results of the backpack's antibacterial performance obtained using the agar plate diffusion method;

[0033] Figure 5 Images showing the color change of A3261-dopamine conjugate / TPU solution sample upon temperature rise;

[0034] Figure 6 The red phase UV-Vis absorption spectrum of the A3261-dopamine conjugate / TPU solution sample is shown in the figure.

[0035] Figure 7 This is a simulation diagram of assembling a backpack. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. In this description, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] A method for preparing a functional fabric includes the following steps:

[0038] S1, double-layer jacquard base fabric is prepared by using fully dull polyester filament as the surface warp yarn, black polyester yarn as the interlayer weft yarn, and silver-plated polyester yarn as the partial reflective yarn. The base fabric is woven with a double-layer jacquard structure. The surface layer is a 5 / 1 right twill and partial satin composite jacquard structure, and the inner layer is a high-density structure. The two layers are connected by a joint structure.

[0039] The double-layer jacquard base fabric forms the skeleton of the entire functional system. The outer layer uses a 5 / 1 right-hand twill and partial satin jacquard weave, which creates a longer float and higher coverage on the fabric surface, thus reducing light-transmitting gaps caused by exposed warp and weft interlacing points. The inner layer uses a high-density weave, primarily serving to block light transmission channels and enhance dimensional stability. The two layers are connected by a webbing structure, allowing the upper and lower layers to maintain relatively independent functional divisions while forming an integrated fabric structure. The warp and weft yarns on the outer layer interlaced to form a continuous coverage area, with localized... The satin weave area has a smoother surface and softer reflection due to the reduced interlacing points; the high-density weave of the inner layer reduces the gaps between yarns, making it difficult for light to penetrate in a straight line; the bonding structure partially locks the upper and lower layers together, preventing separation of the two layers and avoiding local light transmission defects caused by too many bonding points; ultimately, a hierarchical structure of surface decoration—intermediate barrier—inner support is formed on the fabric cross-section; the internal porosity, yarn coverage, and interlayer channel continuity of the fabric are controlled through the design of the weave structure, providing a stable supporting base for the subsequent light-blocking layer, antibacterial layer, and color-developing layer;

[0040] S2, Light-blocking and heat-insulating layer construction: A light-blocking and heat-insulating layer is introduced into the middle layer, back layer, or interlayer interface of the double-layer jacquard base fabric. The light-blocking and heat-insulating layer includes a black light-absorbing component, a metallized reflective component, and a fully dull cross-section fiber component. The black light-absorbing component is 150D black low-elastic heavy-duty yarn, the metallized reflective component is silver-plated polyester fiber, and the fully dull cross-section fiber component is W-shaped cross-section fully dull polyester filament. Among them, the 150D black low-elastic heavy-duty yarn is set as the main light-blocking weft yarn in the light-blocking area in the middle of the fabric, the silver-plated polyester fiber is set in the reflection enhancement area near the light-receiving side, and the W-shaped cross-section fully dull polyester filament is set on the surface layer of the fabric to form a composite light-blocking jacquard fabric.

[0041] Among them, 150D black low-elastic heavy-duty mesh yarn serves as the main light-shielding component, utilizing the strong absorption of visible light by the black system to convert incident light energy into heat energy and attenuate the intensity of transmitted light; silver-plated polyester fiber serves as the metallized reflective component, relying on the high reflectivity of the metal surface to light and heat radiation to reflect some incident light and near-infrared radiation back to the outside world; W-shaped cross-section fully dull polyester filament serves as the surface scattering control component, causing multiple refractions, reflections and scatterings through the irregular cross-section, and reducing surface specular reflection, thereby weakening direct transmission and glare; the black low-elastic heavy-duty mesh yarn, due to its loose filament bundle and numerous network nodes, can form a more complex light propagation path; the silver-plated polyester fiber surface has a continuous or semi-continuous metal reflective layer, which causes strong reflection on the fiber surface after incident light is irradiated; the concave and convex edges of the W-shaped cross-section fiber cause light to be deflected at multiple angles on the fiber surface and inside, reducing directional transmission. As a result, multiple light path attenuation phenomena occur inside the fabric: some light is absorbed, some light is reflected, and some light is scattered and its path is extended and further absorbed by the adjacent black components, which ultimately significantly reduces the light transmittance and slows down the heat transfer inward. The three factors together form a composite light-blocking mechanism of absorption-reflection-scattering.

[0042] S3, PA latex preparation: Using 1L of deionized water as solvent, nitrogen was purged to remove oxygen. 50g of methyl methacrylate, 50g of butyl acrylate, and 5g of sodium dodecylbenzenesulfonate (SDBS) were added and mixed thoroughly with magnetic stirring. The mixture was then heated to 80℃. 3g of potassium sulfate was dissolved in 100ml of deionized water and added to the mixture. The reaction was stirred for 5 hours under a nitrogen atmosphere to obtain PA latex. PA latex is obtained through emulsion polymerization of methyl methacrylate and butyl acrylate in an aqueous phase. SDBS acts as an emulsifier, enabling the hydrophobic monomers to form stable droplets in water. Nitrogen purging removes oxygen to eliminate its inhibitory effect on free radical polymerization. The initiator decomposes at 80℃ to generate free radicals, initiating the polymerization of monomers. The polymerization process forms polymer particles, resulting in PA latex, a flexible polymer dispersion system that can penetrate into the interstices of fabric fibers and form a continuous, flexible film after drying. This film provides a bonding interface for Cu2O particles and optical microspheres. In the early stages of the reaction, polymer nuclei preferentially form in monomer droplets and micelles. As polymerization proceeds, the polymer particles gradually grow and become stably suspended in water, forming a milky white latex. After drying, the latex particles come into contact with each other, compact, deform, and fuse under the drive of water evaporation, ultimately forming a continuous polymer film. This polymer film constructs a flexible bonding network on the fiber surface and in the pores between fibers, enabling subsequent particles and microspheres to adhere and maintain high durability.

[0043] S4, Preparation of Cu2O antibacterial particles: Weigh 15g polyvinylpyrrolidone (PVP), 5.5g sodium citrate dihydrate and 5.2g copper acetate monohydrate, add 300ml ethylene glycol and 1L deionized water in sequence, stir magnetically for 20min and sonicate for 20min, then add 200ml of 0.4mol / L NaOH solution, and add a total of 150mL of 0.2mol / L ascorbic acid solution in two steps, stir for 60min, centrifuge for 10min, wash and freeze-dry for 5h, disperse 0.5g of freeze-dried powder in 100mL anhydrous ethanol to obtain a dispersion containing Cu2O antibacterial particles;

[0044] Cu2O particles were prepared using a liquid-phase reduction method. Copper acetate monohydrate provided the copper source, NaOH adjusted the alkaline environment and promoted the formation of copper hydroxide precursors from copper ions, and ascorbic acid, as a reducing agent, reduced the high-valent copper precursors to monovalent cuprous oxide. PVP and sodium citrate played a role in dispersion, complexation, and confined growth, inhibiting particle agglomeration and controlling particle size. The Cu2O particles obtained by this method have good dispersibility and surface activity, which is beneficial for the subsequent construction of antibacterial layers. During the reaction, copper ions first formed a blue or blue-green precursor complex and precipitation system under alkaline conditions, and then gradually transformed into an orange-red or brick-red Cu2O particle suspension under the reduction of ascorbic acid. Microscopically, crystal nuclei formed first, and then slowly grew under the adsorption and regulation of PVP and sodium citrate, avoiding unlimited particle agglomeration. After centrifugation, washing, and freeze-drying, Cu2O powder with good dispersibility was obtained. After redispersing it in ethanol, the particles maintained a relatively stable dispersion in the solution, which is convenient for spray coating.

[0045] S5, Antibacterial layer construction: The composite light-blocking jacquard fabric is immersed in a 50% ethanol solution and ultrasonically washed for 3 hours. After drying, it is cut into pieces and then sprayed with PA latex emulsion on the inside of the fabric and dried. Then, 50-300 μl of Cu2O antibacterial particle dispersion is sprayed and dried at 60℃ for 15 minutes. The Cu2O antibacterial particles are embedded in the PA latex to form the PA layer.

[0046] First, the fabric is ultrasonically washed with 50% ethanol to remove oil, dust, and weakly adsorbed impurities from the fabric surface, improving surface wettability and the adhesion of subsequent coatings. PA latex is sprayed, followed by Cu2O dispersion to first establish a flexible adhesive layer, and then embed Cu2O particles into it. Drying at 60℃ allows the solvent to evaporate and promotes the PA latex to form a film, thereby fixing the Cu2O particles semi-embedded and fixed on the inner surface of the fabric. This reduces particle shedding while retaining some particles exposed on the surface as an antibacterial active interface. After spraying, the PA latex first wets the fiber surface and penetrates into the fiber gaps. As the moisture evaporates, the latex particles melt and form a film. Subsequently, the sprayed Cu2O particles adhere to the surface of the not-yet-fully-cured PA layer under the action of droplet spreading, and are partially pressed into the interior of the PA layer during the drying process, forming a semi-embedded structure with the lower part embedded and the upper part exposed. The composite interface consists of fiber, PA continuous membrane, and Cu2O particles. The exposed Cu2O particles can come into contact with bacteria and exert an antibacterial effect, while the embedded part improves the adhesion of the particles and slows down the shedding during use.

[0047] S6, Preparation of Composite Optical Microspheres: 5g ammonium bicarbonate and 1L deionized water were purged with nitrogen for 10 min, followed by the addition of 190g styrene, 10g methyl methacrylate, and 10g acrylic acid. 110mg sodium dodecylbenzenesulfonate (SDBS) was then added. The mixture was pre-emulsified for 1.5h at 75℃ and 350rpm with stirring. 200mL of an aqueous solution containing 3.6g ammonium persulfate was then added to initiate the reaction for 4h, followed by aging at 80℃ for 2h to obtain a monodisperse composite optical microsphere dispersion (70mg-150mg).

[0048] 110 mg of sodium dodecylbenzenesulfonate can produce composite optical microspheres with a target particle size of about 230–245 nm. The structural color is green, which is used to avoid the color development layer. Below 100 mg, the structural color is yellowish-green, and above 120 mg, it is bluish-green.

[0049] Monodisperse composite optical microspheres were prepared by emulsion polymerization. Styrene provided a rigid framework, methyl methacrylate improved the mechanical stability of the microspheres, acrylic acid provided surface polar groups, which is beneficial to subsequent dispersion stability and interfacial interaction with the substrate, SDBS controlled the nucleation number and microsphere particle size, ammonium persulfate initiated free radical polymerization, and ammonium bicarbonate played a buffering and system stabilizing role, resulting in microspheres with uniform particle size and good dispersibility, so as to achieve ordered self-assembly during the subsequent coating and drying process.

[0050] S7, Color development layer construction: PA latex emulsion is pre-coated on the outer surface of the fabric, and then monodisperse composite optical microsphere dispersion is coated onto the same surface using a scraper at a speed of 1 cm / s. After drying, a fabric with a color development layer is obtained.

[0051] The core of the color-developing layer construction is evaporation-induced self-assembly. First, PA latex is pre-coated on the fabric surface to improve the smoothness and adhesion of the fabric surface and reduce the disordered accumulation of microspheres when they are directly deposited on the undulating surface of the fiber. Then, by controlling the thickness of the liquid film and the evaporation rate through scraping, the monodisperse composite optical microspheres gradually become ordered during the solvent evaporation process. When the microsphere particle size and arrangement period match the wavelength of visible light, the fabric surface exhibits structural color, rather than traditional dye coloring. In the liquid film after scraping, the microspheres are initially in a random dispersion state. As the solvent evaporates and the liquid level drops, capillary force, electrostatic effect, and the balance of repulsion and attraction between particles drive the microspheres to tend to pack tightly, gradually forming a locally ordered arrangement structure. After drying, the microsphere array is fixed on the surface of the PA layer and forms a periodic refractive index change. A regular spacing is formed between adjacent microspheres. The incident light undergoes selective Bragg reflection in this periodic structure, thus presenting a structural color appearance such as blue, green, and yellow.

[0052] S8, Composite Setting, involves hot-pressing the fabric with a 210D nylon lining to create a functional fabric. The main function of composite setting is to stably bond the functional layer fabric with the 210D nylon lining, forming an integral composite material suitable for backpack fabrication. During hot pressing, the outer functional fabric and the nylon lining adhere tightly under temperature and pressure. The PA layer and related interface materials soften, flow, and re-bond, thereby improving interlayer peel strength and overall dimensional stability, reducing interlayer displacement during subsequent cutting, sewing, and use. Under hot pressing, the tiny gaps between layers are compressed, significantly increasing the interfacial contact area. The PA interface layer softens upon heating and penetrates into the micropores on the fiber and lining surfaces, forming mechanical interlocking and interfacial bonding upon cooling. The contact between the nylon lining and the functional fabric gradually changes from point contact to surface contact. Microscopically, this results in a denser interlayer interface, reduced porosity, and a more uniform composite layer thickness, thus improving overall abrasion resistance and formability.

[0053] The functional fabric also includes a temperature-sensitive early warning layer, the preparation of which includes the following steps:

[0054] K1, DA3261-dopamine conjugate synthesis: 10g of 10,12-pentacarbazide diacetic acid (DA3261) was dissolved in 200ml of dichloromethane, filtered to remove polymerized impurities, and rotary evaporated to obtain pure DA3261; 1.8g of DA3261 and 0.138g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) were dissolved in 200ml of dichloromethane, and 0.82g of N-hydroxysuccinimide (NHS) was added. The reaction was carried out at 25℃ for 4h to obtain DA3261-NHS; then 1.5g of DA3261-NHS and 0.72g of dopamine were dissolved in 200ml of N,N-dimethylformamide (DMF), and 0.38g of triethylamine was added. The reaction was carried out at 25℃ under nitrogen for 12h with stirring to obtain DA3261-dopamine conjugate powder;

[0055] The carboxyl group is activated by EDC and NHS, and then undergoes an amidation coupling reaction with dopamine molecules. The DA3261 molecule contains a diyne structure and a carboxyl group. It first generates an active ester intermediate DA3261-NHS under the action of EDC and NHS, and then reacts with the amino group of the dopamine molecule to form a stable amide bond. The introduction of the dopamine group improves the polarity and interfacial adhesion of the material on the one hand, and provides better compatibility for subsequent composite with TPU and local coating on the other hand. The original DA3261 molecule is transformed from a relatively simple hydrophobic diyne chain structure into a new molecule with an aromatic ortho-diphenol structure and amide bond connection, which enhances molecular polarity and changes the intermolecular interaction mode. The product after coupling is more easily and uniformly dispersed in the TPU system during the subsequent film formation process and forms a more stable composite distribution on the substrate surface.

[0056] K2, Preparation of the temperature-sensitive layer: 10g TPU was added to 190g DMF and stirred at 45℃ until completely dissolved to obtain a 5% TPU solution; 50mg DA3261-dopamine coupling powder was added to 30ml TPU solution, dissolved by ultrasonication, poured into a mold or locally coated on a predetermined area of ​​the fabric, dried at 80℃ to remove N,N-dimethylformamide DMF, and photopolymerized with 254nm ultraviolet light to form a DA3261-dopamine coupling / TPU temperature-sensitive layer;

[0057] After TPU is dissolved in DMF, a homogeneous and flexible polymer solution is formed, in which DA3261-dopamine conjugate is uniformly dispersed. After drying to remove DMF, the TPU forms a flexible and continuous film, immobilizing diyne molecules within the film; subsequently, it is subjected to 254... When exposed to UV light at nm, the diacetylene monomers undergo 1,4-addition topological polymerization to form conjugated polyacetylene segments. The polyacetylene backbone is sensitive to changes in external temperature; upon heating, its chain conformation and conjugation length change, resulting in changes in the absorption spectrum and a color transition, forming a temperature-sensitive warning functional layer. In the initial stage of coating, the TPU molecular chains and DA3261-dopamine conjugate are in a uniformly mixed or microphase dispersed state. After drying, the TPU forms a continuous matrix, essentially embedding the temperature-sensitive component within a flexible network. After UV irradiation, the diacetylene monomers polymerize along specific spatial arrangements, forming polyacetylene microregions with long-range conjugated structures. As the temperature rises, these conjugated segments shift from a more regular state to a twisted or relaxed state, leading to changes in the degree of electron delocalization, which macroscopically manifests as a color change from the initial color to the warning color. The presence of the TPU matrix also buffers stress, inhibits brittleness, and improves the integrity of the temperature-sensitive layer under bending conditions.

[0058] Prepare a 10ml sample of DA3261-dopamine coupling compound / TPU solution in K2 that has not undergone UV photopolymerization. Irradiate with 254nm UV light and maintain a heating rate of 5℃ / min, then take real-time photographs to obtain the following results: Figure 5 and Figure 6The temperature-induced color change image and blue / red phase UV-Vis absorption spectrum chart show that the solution changes from light blue to blue-violet at 30℃, completely changes from blue-violet to purple at 35℃, and further changes to purplish-red at 40℃. When the temperature rises to 45℃, the maximum absorption wavelength of the DA3261-dopamine conjugate / TPU solution shifts from 640nm to 545nm, corresponding to the color change from purplish-red to red. As the temperature further increases, the peak intensity at 540nm gradually increases. When the temperature increases to 70℃, the peak at 640nm disappears, leaving only the absorption peak at 540nm. It can be seen that the absorption peak at 640nm has always been dominant between 25℃ and 40℃. When the temperature rises to 45℃, the maximum absorption peak shifts to around 540nm. The DA3261-dopamine conjugate / TPU solution exhibits multi-level temperature-responsive color change performance with increasing temperature.

[0059] like Figure 7 As shown, an assembled backpack includes the following panels: a front panel, a back panel, side panels, a bottom panel, a flap, shoulder strap connectors, and an inner compartment divider. Some of the panels are assembled from functional fabrics prepared using the above-described method. The color-developing layer and the thermosensitive layer of the functional fabric face outwards, while the antibacterial layer faces inwards. The front panel and flap are provided with color-developing and thermosensitive layers. The outer periphery of the inner compartment divider has a light-blocking and heat-insulating enhancement area. The inner compartment divider is positioned with the antibacterial layer facing inwards. Arranging the color-developing and thermosensitive layers outwards maximizes visual recognition and temperature visualization warning effects. Arranging the antibacterial layer inwards enhances the adhesion between the backpack contents and the contents. The antibacterial effect when the inner cavity comes into contact with air; the light-shielding and heat-insulating enhancement zone is set in the outer perimeter of the inner compartment to form a heat barrier and light barrier around sensitive items such as computers, medicines, and food. This partitioned assembly method reflects the integrated matching of material function and backpack structure purpose; during use, external light and heat first act on the outer color-sensitive / thermally sensitive area. The thermosensitive layer undergoes a molecular conformation change when heated, resulting in a color warning; the absorption-reflection-scattering structure inside the light-shielding and heat-insulating zone weakens the heat from continuing to be transferred inward; the Cu2O particles in the inner antibacterial layer continuously form an antibacterial active interface on the surface of the backpack's inner cavity, thus forming a continuous functional gradient of outer layer response - middle layer barrier - inner layer protection;

[0060] After being polymerized under ultraviolet light, the temperature-sensitive layer is blue-purple at temperatures below 35°C. When the temperature rises to the warning temperature (>40°C), it turns purple and then gradually deepens to red, so as to achieve graded and visual early warning of temperature anomalies.

[0061] The color-developing layer has a green structural color that forms a high contrast with the color-changing path of the thermosensitive layer, in order to avoid visual confusion between the color-developing layer and the initial and warning colors of the thermosensitive layer;

[0062] To verify whether the temperature-sensitive layer on the outer surface of the backpack can generate an identifiable, graded, and repeatable color warning response under normal environmental temperature rise and abnormal heat accumulation conditions, the following four groups of samples were designed:

[0063] Experimental Group A: Backpack front panel sample made of functional fabric, including: double-layer jacquard base fabric, light-blocking and heat-insulating layer, color developing layer, DA3261-dopamine coupling agent / TPU thermosensitive layer; the thermosensitive layer was prepared by using 5% TPU by mass, drying at 80℃ to form a film, and polymerizing under 254nm ultraviolet light.

[0064] Control group B: has the same structure as experimental group A, but does not contain a temperature-sensitive layer, and only retains the color developing layer, light-blocking layer and base fabric layer;

[0065] Control group C: The structure is the same as that of experimental group A, but the DA3261-dopamine conjugate in the temperature-sensitive layer is removed, and only a pure TPU thin layer is retained to eliminate the overall color change caused by the heat of TPU itself;

[0066] Control group D: Used ordinary backpack fabric (210D nylon composite layer), without temperature-sensitive layer and color-developing layer, as a traditional backpack control;

[0067] The testing methods include:

[0068] Temperature-increase color development test, by analyzing the color difference changes in the CIELab color space ( E), under a D65 light source, use a colorimeter to record the L, a, and b values ​​of the sample at different temperatures, and then...

[0069] E= ;

[0070] Calculate the overall color difference compared to the initial state;

[0071] The sample was cut into 5cm×5cm pieces and placed on a constant temperature heating platform. The initial temperature was 25℃, and then the temperature was gradually increased to 30℃, 35℃, 40℃, 45℃ and 50℃. After holding the temperature at each level for 5 minutes, the color photos and Lab data were recorded. Each group of samples was tested in parallel 3 times and the average value was taken.

[0072] Early warning judgment criteria:

[0073] ΔE < 5, visual changes are not obvious, and no warning is triggered;

[0074] 5≤ΔE<15, minor warning;

[0075] 15≤ΔE<30, a clear warning;

[0076] ΔE≥30: Strong warning;

[0077] like Figure 1 The chart shows the test results of the backpack's temperature-sensitive warning performance. Test group A showed a change from blue-purple to purple at 35℃, with a ΔE of 12.6, which can be defined as a level one warning. At 40℃, it turned purplish-red, with a ΔE of 28.7, entering the obvious warning zone. Above 45℃, it turned red, with a ΔE greater than 30, indicating a strong warning. This trend conforms to the pattern of turning purple at 25℃, starting to change at 35℃, and rapidly increasing ΔE above 40℃. Control groups B, C, and D all had ΔE less than 3, indicating that ordinary color-developing layers, pure TPU layers, and traditional backpack fabrics do not have a recognizable warning function at the same temperature range. Therefore, the warning signal mainly originates from the DA3261-dopamine coupling agent / TPU temperature-sensitive layer, rather than the structural color layer or the thermal deformation of the base fabric.

[0078] Simulating internal heat source scenarios, such as placing a used computer in the inner compartment without cooling it down, a constant-temperature heating element was placed on the inside of the backpack's front panel. The temperature was set to three levels: 38°C, 42°C, and 48°C, and maintained for 10 minutes. The color change of the temperature-sensitive area on the outer surface was observed. Figure 2 The diagram shown is a test chart of heat source warning inside the backpack, indicating that the warning is not an isolated test of the membrane and is still effective in the backpack assembly structure.

[0079] To verify the inhibitory effect of the antibacterial layer inside the backpack on common bacteria, especially Escherichia coli and Staphylococcus aureus, and to compare the antibacterial differences under different Cu2O loadings, the following four sample groups were designed:

[0080] Experimental group A1, backpack inner compartment layer sample, antibacterial layer sprayed with Cu2O dispersion 100μL / 5cm×10cm;

[0081] Experimental group A2: Cu2O dispersion spraying amount 200μL / 5cm×10cm;

[0082] Experimental group A3, Cu2O dispersion spraying amount 300μL / 5cm×10cm;

[0083] Control group B1 only has a chromogenic layer and a PA layer, and does not contain Cu2O antibacterial particles;

[0084] Control group C1: ordinary backpack lining, without Cu2O and without PA;

[0085] According to GB / T20944.3-2008 shaking method, Escherichia coli and Staphylococcus aureus were used as test strains to calculate the inhibition rate. According to GB / T20944.1-2007 agar plate diffusion method, the width of the inhibition band was measured. The samples were cut into 5cm×10cm pieces, the incubation temperature was 37℃, the incubation time was 24h, and there were 3 parallel samples in each group.

[0086] like Figure 3The chart shows the results of the backpack's antibacterial performance test obtained using the shaking method. For *Escherichia coli*, the antibacterial activity was approximately 99.57%, 99.95%, 99.99%, and 99.99% for 50 / 100 / 200 / 300 μL samples, respectively; and for *Staphylococcus aureus*, approximately 96.34%, 99.76%, 99.99%, and 99.99%, respectively. Figure 4 The chart shows the results of the backpack's antibacterial performance test obtained using the agar plate diffusion method. Experimental groups A1-A3 showed significant antibacterial activity against both types of bacteria. The 100 μL group achieved an inhibition rate of 99.95% against *Escherichia coli* and 99.76% against *Staphylococcus aureus*, indicating that when the Cu2O loading is approximately 0.5 mg / cm³... 2 When the Cu2O loading increases from 100μL to 200μL and 300μL, the antibacterial rate tends to plateau, both approaching 99.99%, indicating that 100μL is the optimal dosage-performance balance point. Although the control group B1 has a certain antibacterial rate, it is significantly lower than that of the experimental group containing Cu2O, indicating that the PA / chromogenic layer itself only has a limited antibacterial auxiliary effect, and the real main antibacterial contribution comes from the Cu2O antibacterial layer.

[0087] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0088] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a functional fabric, characterized in that, Includes the following steps: S1, double-layer jacquard base fabric is prepared by using fully dull polyester filament as the surface warp yarn, black polyester yarn as the interlayer weft yarn, and silver-plated polyester yarn as the partial reflective yarn. The base fabric is woven with a double-layer jacquard structure. The surface layer is a 5 / 1 right twill and partial satin composite jacquard structure, and the inner layer is a high-density structure. The two layers are connected by a joint structure. S2, Light-blocking and heat-insulating layer construction: A light-blocking and heat-insulating layer is introduced into the middle layer, back layer, or interlayer interface of the double-layer jacquard base fabric. The light-blocking and heat-insulating layer includes a black light-absorbing component, a metallized reflective component, and a fully dull cross-section fiber component. The black light-absorbing component is 150D black low-elastic heavy-duty yarn, the metallized reflective component is silver-plated polyester fiber, and the fully dull cross-section fiber component is W-shaped cross-section fully dull polyester filament. Among them, the 150D black low-elastic heavy-duty yarn is set as the main light-blocking weft yarn in the light-blocking area in the middle of the fabric, the silver-plated polyester fiber is set in the reflection enhancement area near the light-receiving side, and the W-shaped cross-section fully dull polyester filament is set on the surface layer of the fabric to form a composite light-blocking jacquard fabric. S3, PA latex preparation: 1L of deionized water was used as solvent, nitrogen was purged to remove oxygen, 50g of methyl methacrylate, 50g of butyl acrylate and 5g of sodium dodecylbenzene sulfonate (SDBS) were added, and the mixture was stirred evenly with magnetic stirring and heated to 80℃. 3g of potassium sulfate was dissolved in 100ml of deionized water and added. The mixture was stirred and reacted for 5h under a nitrogen atmosphere to obtain PA latex. S4, Preparation of Cu2O antibacterial particles: Weigh 15g polyvinylpyrrolidone (PVP), 5.5g sodium citrate dihydrate and 5.2g copper acetate monohydrate, add 300ml ethylene glycol and 1L deionized water in sequence, stir magnetically for 20min and sonicate for 20min, then add 200ml of 0.4mol / L NaOH solution, and add a total of 150mL of 0.2mol / L ascorbic acid solution in two steps, stir for 60min, centrifuge for 10min, wash and freeze-dry for 5h, disperse 0.5g of freeze-dried powder in 100mL anhydrous ethanol to obtain a dispersion containing Cu2O antibacterial particles; S5, Antibacterial layer construction: The composite light-blocking jacquard fabric is immersed in a 50% ethanol solution and ultrasonically washed for 3 hours. After drying, it is cut into pieces and then sprayed with PA latex emulsion on the inside of the fabric and dried. Then, 50-300 μl of Cu2O antibacterial particle dispersion is sprayed and dried at 60℃ for 15 minutes. The Cu2O antibacterial particles are embedded in the PA latex to form the PA layer. S6, Preparation of composite optical microspheres: 5g ammonium bicarbonate and 1L deionized water were purged with nitrogen for 10 min, then 190g styrene, 10g methyl methacrylate and 10g acrylic acid were added, along with 70mg-150mg sodium dodecylbenzenesulfonate (SDBS). The mixture was pre-emulsified at 75℃ and 350rpm for 1.5h, then 200mL of an aqueous solution containing 3.6g ammonium persulfate was added to initiate the reaction for 4h, followed by aging at 80℃ for 2h to obtain a monodisperse composite optical microsphere dispersion. S7, Color development layer construction: PA latex emulsion is pre-coated on the outer surface of the fabric, and then monodisperse composite optical microsphere dispersion is coated onto the same surface using a scraper at a speed of 1 cm / s. After drying, a fabric with a color development layer is obtained. S8, Composite Finishing, involves hot-pressing the fabric with a 210D nylon lining to obtain a functional fabric.

2. The method for preparing a functional fabric according to claim 1, characterized in that, The functional fabric also includes a temperature-sensitive early warning layer, the preparation of which includes the following steps: K1, DA3261-dopamine conjugate synthesis: 10g of 10,12-pentacarbazide diacetic acid (DA3261) was dissolved in 200ml of dichloromethane, filtered to remove polymerized impurities, and rotary evaporated to obtain pure DA3261; 1.8g of DA3261 and 0.138g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) were dissolved in 200ml of dichloromethane, and 0.82g of N-hydroxysuccinimide (NHS) was added. The reaction was carried out at 25℃ for 4h to obtain DA3261-NHS; then 1.5g of DA3261-NHS and 0.72g of dopamine were dissolved in 200ml of N,N-dimethylformamide (DMF), and 0.38g of triethylamine was added. The reaction was carried out at 25℃ under nitrogen for 12h with stirring to obtain DA3261-dopamine conjugate powder; K2, Preparation of the temperature-sensitive layer: 10g TPU was added to 190g DMF and stirred at 45℃ until completely dissolved to obtain a 5% TPU solution; 50mg DA3261-dopamine coupling powder was added to 30mTPU solution, dissolved by ultrasonication, poured into a mold or locally coated on a predetermined area of ​​the fabric, dried at 80℃ to remove N,N-dimethylformamide DMF, and photopolymerized with 254nm ultraviolet light to form a DA3261-dopamine coupling / TPU temperature-sensitive layer.

3. An assembled backpack, comprising the following panels: a front panel, a back panel, side panels, a bottom panel, a flap, shoulder strap connectors, and an inner compartment, characterized in that, Some of the cut pieces are assembled from functional fabrics prepared by the preparation method described in any one of claims 1-2, wherein the color-developing layer and the temperature-sensitive layer of the functional fabric face the outside of the backpack, and the antibacterial layer of the functional fabric faces the inside of the backpack.

4. The assembled backpack according to claim 3, characterized in that, The front panel and flip cover are equipped with a color-developing layer and a temperature-sensitive layer. The outer periphery of the inner compartment partition is equipped with a light-shielding and heat-insulating enhancement area. The inner compartment partition is designed with an antibacterial layer facing inwards.

Images