Fabric with thermal response and unidirectional moisture conductivity and preparation method thereof

Abstract

The invention discloses a fabric with thermal response and unidirectional moisture conductivity and a preparation method thereof, belonging to the technical field of intelligent textiles. Dicumyl peroxide is dissolved in a chloroform solution of ethylene-vinyl acetate copolymer, the solvent is removed to obtain a mixture, the mixture is extruded to obtain polymer fibers, and the polymer fibers are subjected to self-nucleation crystallization to obtain shape memory polymer fibers; cotton fibers and the shape memory polymer fibers are composite twist-woven in a plain weave manner to obtain a primary fabric; and a sodium methyl silicate waterproofing agent is sprayed on the primary fabric to obtain a fabric with thermal response and unidirectional moisture conductivity. The heat and moisture management composite fabric prepared by the invention has good heat and moisture management effect, can be applied to clothing, is comfortable to use, and has excellent moisture conductivity.

Description

Technical Field

[0001] The present invention relates to the technical field of smart textiles, and in particular to a textile with thermal response and unidirectional moisture conductivity and a preparation method thereof. Background Art

[0002] With human progress and technological advancements, thermal and moisture comfort has become a fundamental and crucial human need. However, traditional space heating and cooling not only consumes enormous amounts of energy but also significantly exacerbates climate change, including global warming. Textiles, as the medium between the human body and the surrounding environment, play a crucial role in regulating the body's temperature and humidity balance. In the early days of thermal management, the focus was on maintaining warmth through controlled heat transfer, using thick fabrics or adding cotton batting for warmth, and some even resorted to metallic-coated fabrics. For cooling, clothing equipped with lightweight, battery-powered fans increases forced ventilation and cools the body. The comfort provided by traditional textiles is limited, as they cannot adjust the heat and humidity balance according to environmental changes. Consequently, textiles with effective thermal and moisture management capabilities are emerging and rapidly developing.

[0003] By combining optoelectronic metamaterials with bulk fiber fabrication technology, Tao Guangming has produced a passive daytime radiative cooling metamaterial that effectively blocks the entire solar radiation band (0.3-2.5μm). Human skin covered with this metamaterial cools down by approximately 4.8°C compared to skin covered with commercial cotton fabric. As a medium between the human body and the surrounding environment, textiles can regulate heat and humidity balance and provide physiological comfort. Thermal management fabrics primarily focus on developing functional textile materials, composite thermally conductive or reflective materials, and integrating smart devices. Moisture management is another key performance characteristic of textiles. Efficient moisture wicking has become a key requirement in the high-end apparel industry, primarily achieved through the development of moisture-wicking fibers, the construction of functional fabric structures, and fabric finishing. Generally speaking, heat and moisture transfer occur simultaneously within fabrics and influence each other. For example, heat accelerates the evaporation of sweat, while fabric moisture enhances heat conduction. Heat and moisture management textiles can flexibly regulate the microclimate near the skin, eliminating the need for extensive heating / cooling or drying.

[0004] To balance heat flow and moisture transport within the human body, the exploration of sustainable, zero-energy, and zero-emission air conditioning technologies is essential. If textiles possess intelligent control capabilities similar to those of air conditioners, human comfort would be significantly improved. Therefore, the research into intelligent and responsive heat and moisture management fabrics that can dissipate heat and moisture in hot environments and retain heat in cold ones is of great significance. Summary of the Invention

[0005] The present invention provides a fabric with thermal response and unidirectional moisture conduction and a preparation method thereof, which effectively solves the technical problems of limited heat and moisture management capabilities, single materials, and weak dynamic intelligence of current textiles. At the same time, it provides a fabric with moisture and heat management that can dissipate heat and conduct moisture in a hot environment and keep warm in a cold environment.

[0006] The first object of the present invention is to provide a method for preparing a fabric having thermal response and unidirectional moisture conductivity, comprising the following steps:

[0007] Dissolving dicumyl peroxide in a chloroform solution of ethylene-vinyl acetate copolymer, removing the solvent to obtain a mixture, extruding the mixture to obtain polymer fibers, thermally cross-linking the polymer fibers at 150-170° C. to obtain shape memory polymer fibers having a network structure, and subjecting the shape memory polymer fibers to self-nucleation crystallization to obtain polymer fibers having thermal response;

[0008] Using cotton fibers and the shape memory polymer fibers for composite twist weaving in a plain weave manner to obtain a primary fabric;

[0009] The primary fabric is sprayed with a sodium methyl silicate waterproofing agent for hydrophobic treatment to obtain a fabric with thermal response and unidirectional moisture conductivity.

[0010] As a preferred embodiment, the weight ratio of dicumyl peroxide to ethylene-vinyl acetate copolymer is 3-4:4-8.

[0011] As a preferred embodiment, the self-nucleation crystallization is specifically as follows: treating the polymer fiber at 90-110°C for 5-15 minutes; keeping it at -5-15°C for 5-15 minutes to cool and shape it, keeping it at 50°C for 5-15 minutes, and then cooling it to -5-15°C and keeping it for 10-45 minutes to perform self-nucleation crystallization.

[0012] As a preferred embodiment, the mass concentration of the sodium methyl silicate waterproofing agent is 0.1-3wt%, and the spraying amount is 5-20g / m 2 .

[0013] As a preferred embodiment, the spraying is performed 1 to 5 times.

[0014] As a preferred embodiment, the thermal crosslinking time is 1 to 3 hours.

[0015] As a preferred embodiment, a single-screw extruder is used for extrusion, and the extrusion process parameters are: extrusion temperature 60-100° C., rotation speed 200-400 r / min, and extrusion diameter 0.5-2 mm.

[0016] As a preferred embodiment, the conditions for the composite twisted braiding are: using 2 to 4 cotton yarn twist groups, and the twist point spacing is 3 to 9 mm.

[0017] As a preferred embodiment, the preparation method of the chloroform solution of the ethylene-vinyl acetate copolymer is as follows: at 45-60°C, 4-8 parts by weight of ethylene-vinyl acetate copolymer particles are added to 96-92 parts of chloroform solution, and stirred at 150-200 r / min for 2-6 hours; when the dicumyl peroxide is dissolved, 3-4 parts by weight of dicumyl peroxide powder are added to 97-96 parts of chloroform solution of ethylene-vinyl acetate copolymer at 45-60°C, stirred at 150-200 r / min for 1-4 hours, and at room temperature for 2-6 days.

[0018] The second object of the present invention is to provide a fabric with thermal response and unidirectional moisture conduction prepared by the above preparation method.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides a fabric with thermal response and unidirectional moisture conduction and a preparation method thereof. The present invention first dissolves ethylene vinyl acetate particles in a chloroform solution, adds diisopropylbenzene peroxide powder to prepare a polymer solution, then dries at room temperature to form a film, extrudes fibers using a screw extruder, performs thermal crosslinking, prepares shape memory polymer fibers, selects cotton fibers of appropriate fineness for composite weaving with the shape memory polymer fibers, and obtains a composite fabric with unidirectional moisture conduction after hydrophobic treatment; wherein, when preparing the polymer solution, ethylene vinyl acetate particles are first dissolved in dechloroform to prepare a polymer solution, and then diisopropylbenzene peroxide powder is added to the polymer solution for mixing, and after the mixing is completed, thermal crosslinking is performed for standby use. When preparing the heat and moisture management composite fabric, the prepared shape memory fibers are composite weaved with cotton fabric, and then a sodium methyl silicate waterproofing agent is sprayed on the fabric surface to obtain a composite fabric with heat and moisture management performance. The heat and moisture management composite fabric obtained by the present invention has a good heat and moisture management effect, can be applied to clothing, has good comfort and excellent moisture conduction performance.

[0021] This invention uses a screw extruder to produce shape-memory fibers. The extruded base material is primarily composed of ethylene-vinyl acetate particles and a semicrystalline copolymer, ethylene-vinyl acetate copolymer (EVA). This low-cost, chemically stable, and simple preparation process facilitates large-scale production when applied to fabrics. By leveraging the synergistic effect of the pores between the composite woven fabric and the pores within individual shape-memory fibers, the dynamic opening and closing of these pores achieves the goal of coordinated heat and moisture management.

[0022] The main raw material of the present invention is cotton fiber. Pure cotton fabrics are non-irritating and have no side effects when in contact with the skin, and offer excellent hygienic properties. Cotton fabrics feature fine fibers, good hygroscopicity, excellent heat resistance, a soft feel, and a low market price. Cotton fibers have good hygroscopicity. Under normal circumstances, the fibers absorb moisture from the surrounding atmosphere, with a moisture content of 8% to 10%. Therefore, when they come into contact with the skin, they feel soft and not stiff. If the humidity of the cotton cloth increases or the ambient temperature rises, the moisture contained in the fibers evaporates completely, maintaining a water balance in the fabric and providing a comfortable feel. Pure cotton fabrics also have excellent heat resistance. At temperatures below 110°C, only moisture evaporates from the fabric without damaging the fibers. Therefore, pure cotton fabrics can be worn at room temperature and are not affected by washing, printing, or dyeing. This improves the washability and wearability of pure cotton fabrics. Because cotton fibers are poor conductors of heat and electricity and possess advantages such as high porosity and elasticity, they can trap large amounts of air between the fibers. Therefore, pure cotton fiber textiles have excellent thermal insulation properties, making people feel warm when wearing pure cotton clothing. The advantages of cotton fiber fully improve the wearing disadvantages of shape memory fiber, making the prepared textile fabrics naturally soft, good at moisture absorption and perspiration, and highly comfortable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 1 is a graph of the unidirectional moisture conductivity index of the thermally responsive and unidirectional moisture conductivity fabric of the present invention and the thermally responsive fabric of Comparative Example 1;

[0024] Figure 2 The dynamic integrated transfer index diagram of the fabric with thermal response and unidirectional moisture conductivity of the present invention and the fabric with thermal response of Comparative Example 1;

[0025] Figure 3 These are wettability graphs of a thermally responsive and unidirectional moisture-conducting fabric according to Example 1 of the present invention and a thermally responsive fabric according to Comparative Example 1; (a) is Comparative Example 1, (b) is Example 1, and (c) and (d) are contact angle test graphs of a droplet penetrating into the hydrophobic layer of the thermally responsive and unidirectional moisture-conducting fabric.

[0026] Figure 4 This is a graph showing the water evaporation rate of the thermally responsive and unidirectional moisture-conducting fabric according to Example 1 of the present invention;

[0027] Figure 5 Graph showing thermal conductivity of the thermally responsive and unidirectional moisture-conducting fabric of Example 1 of the present invention and the thermally responsive fabric of Comparative Example 1; wherein the graph before treatment represents Comparative Example 1, and the graph after treatment represents Example 1;

[0028] Figure 6Graphs showing the air permeability of the thermally responsive and unidirectional moisture-conducting fabric of Example 1 and the thermally responsive fabric of Comparative Example 1; the graph before treatment represents Comparative Example 1, and the graph after treatment represents Example 1;

[0029] Figure 7 This is an infrared thermal imaging test image of the shape memory process of the fabric with thermal response and unidirectional moisture conductivity in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention is further described below with reference to specific examples and accompanying drawings. However, the examples are not intended to limit the present invention. The following experimental and detection methods are conventional methods unless otherwise specified; the reagents and raw materials are commercially available unless otherwise specified.

[0031] In response to the technical problems of limited heat and moisture management capabilities, single materials, and weak dynamic intelligence in existing textiles, the present invention provides a fabric with thermal response and unidirectional moisture conductivity and a preparation method thereof. Dicumyl peroxide is dissolved in a chloroform solution of ethylene-vinyl acetate copolymer, the solvent is removed to obtain a mixture, the mixture is extruded to obtain polymer fibers, the polymer fibers are thermally cross-linked at 150-170°C to obtain shape memory polymer fibers with a network structure, and the shape memory polymer fibers are self-nucleated and crystallized to obtain polymer fibers with thermal response; cotton fibers and the shape memory polymer fibers are composite twist-woven in a plain weave manner to obtain a primary fabric; sodium methyl silicate waterproofing agent is sprayed on the primary fabric to obtain a fabric with thermal response and unidirectional moisture conductivity. The heat and moisture management composite fabric prepared by the present invention has good heat and moisture management effect, can be applied to clothing, is comfortable to use, and has excellent moisture conductivity.

[0032] The technical solution of the present invention is analyzed and explained below.

[0033] The present invention first provides a method for preparing a fabric having thermal response and unidirectional moisture conductivity, comprising the following steps:

[0034] Dissolving dicumyl peroxide in a chloroform solution of ethylene-vinyl acetate copolymer, removing the solvent to obtain a mixture, extruding the mixture to obtain polymer fibers, thermally cross-linking the polymer fibers at 150-170° C. to obtain shape memory polymer fibers having a network structure, and subjecting the shape memory polymer fibers to self-nucleation crystallization to obtain polymer fibers having thermal response;

[0035] The preparation method of the chloroform solution of the ethylene-vinyl acetate copolymer is as follows: at 45-60° C., 4-8 parts by weight of ethylene-vinyl acetate copolymer particles are added to 96-92 parts of chloroform solution, and stirred at 150-200 r / min for 2-6 hours; when the dicumyl peroxide is dissolved, 3-4 parts by weight of dicumyl peroxide powder are added to 97-96 parts of the chloroform solution of the ethylene-vinyl acetate copolymer at 45-60° C., and stirred at 150-200 r / min for 1-4 hours, and then kept at room temperature for 2-6 days.

[0036] Using cotton fibers and the shape memory polymer fibers for composite twist weaving in a plain weave manner to obtain a primary fabric;

[0037] The primary fabric is sprayed with a sodium methyl silicate waterproofing agent to obtain a fabric with thermal response and unidirectional moisture conductivity.

[0038] It should be noted that the weight ratio of dicumyl peroxide to ethylene-vinyl acetate copolymer is 3-4:4-8. If the weight ratio of dicumyl peroxide to ethylene-vinyl acetate copolymer exceeds the specified dosage range, regardless of whether the amount of either substance is too much or too little, the prepared polymer fiber will have poor shape memory properties, or even no shape memory properties. That is, the polymer fiber cannot undergo length-short deformation when thermally actuated, resulting in the inability of the pores in the final fabric to open and close, thereby causing the fabric to lose its thermal regulation properties.

[0039] The self-nucleation crystallization method specifically comprises: treating the polymer fiber at 90-110°C for 5-15 minutes; cooling and shaping at -5--15°C for 5-15 minutes; maintaining at 50°C for 5-15 minutes; and then cooling to -5--15°C and maintaining for 10-45 minutes for self-nucleation crystallization. The self-nucleation crystallization (SNC) method expands the melting temperature range and constructs two crystal phases with different layer thicknesses and melting temperatures, thereby reducing and expanding the shape memory response temperature range. When the crystals partially melt at 50°C, the remaining crystals recrystallize during the cooling process, the crystals become thicker, and the Tm increases compared to the original value. As a result, the melting peak of the EVA network changes from a single peak to a double peak, the peak area becomes wider, and the maximum Tm also increases from 60.6°C to 64.5°C. Partial crystal melting occurs, while some crystals remain in a crystalline state. Then, during the cooling process, the remaining crystals act as self-seeds to accelerate the recrystallization of the molten chain segments. These thickened lamellae are called annealed lamellae, and their Tm is increased compared to the original lamellae. The newly formed lamellae are thinner, called pristine lamellae, and their Tm is decreased compared to the original lamellae. When the annealed lamellae and pristine lamellae serve as the backbone and driving phases, respectively, in a 2W-SMP, the polymer network exhibits excellent 2W-SME. Furthermore, the backbone phase remains intact during subsequent heating and cooling cycles, thus providing stability for multiple reversible deformations.

[0040] In order to ensure that the final prepared fabric has better unidirectional moisture conductivity, the mass concentration of the sodium methyl silicate waterproofing agent is 0.1-3wt%, and the spraying amount is 5-20g / m 2 The number of spraying is 1 to 5 times. As the number of spraying increases, the hydrophobic layer on the surface of the fabric becomes thicker and the one-way moisture conduction effect becomes worse. That is, as the number of spraying increases again, the dynamic transfer comprehensive index decreases.

[0041] To ensure the prepared polymer fibers possess an optimal network structure and shape memory properties, the thermal crosslinking time is 1 to 3 hours. Temperatures below 150°C prevent crosslinking between the peroxide DCP and EVA, resulting in a lack of shape memory properties in the prepared fiber material. Temperatures above 170°C increase the polymer's crosslinking density, causing the material to lose flexibility and ductility, affecting the polymer's mechanical properties and chemical stability, and altering the fiber's color, impacting its aesthetics and application.

[0042] In order to further ensure the shape memory performance of the polymer fiber, a single-screw extruder is used for extrusion, and the extrusion process parameters are: extrusion temperature 60-100°C, rotation speed 200-400r / min, and extrusion diameter 0.5-2mm. The extrusion diameter is the diameter of the polymer fiber, and the extrusion process parameters have a great influence on the appearance morphology of the polymer fiber and the extrusion forming effect. When extrusion is carried out under the extrusion parameters defined here, the polymer fibers obtained are uniform in thickness, high in continuity, and have excellent shape memory performance. If other extrusion parameters are used to prepare polymer fibers, since continuous fiber filaments cannot be extruded, the uniformity of fiber thickness decreases, and the shape memory performance of the polymer fibers is poor, which inevitably leads to poor overall performance of the fabric finally prepared.

[0043] The composite twisted braiding process utilizes 2-4 cotton yarn twists with a twist point spacing of 3-9 mm. These parameters ensure that the fabric possesses a partially composite porous structure. When the shape memory polymer fibers undergo thermal deformation, the composite structure partially opens to dissipate heat, thereby ensuring the fabric achieves a thermoregulatory effect.

[0044] The technical effects of the present invention are described below with reference to specific embodiments and comparative examples.

[0045] Example 1

[0046] A method for preparing a fabric having thermal response and unidirectional moisture conductivity comprises the following steps:

[0047] (1) First, 25 wt% of ethylene-vinyl acetate copolymer was dissolved in chloroform in a weight ratio of 3:8 between dicumyl peroxide and ethylene-vinyl acetate copolymer. The dissolution process was performed by heating in a 55°C water bath and stirring at 180 rpm for 3 hours to obtain a chloroform solution of ethylene-vinyl acetate copolymer. Then, 3 wt% of dicumyl peroxide was added to the chloroform solution of ethylene-vinyl acetate copolymer, and heating and stirring were continued at 55°C for 1 hour. Finally, the mixed solution was inverted into a glass dish and the solvent was evaporated and dried at room temperature for 3 days to obtain a mixture.

[0048] (2) using a micro single-screw extruder to produce polymer fibers with a diameter of 1 mm at 60° C. and a rotation speed of 300 r / min;

[0049] (3) thermally crosslinking the polymer fiber in an oven at 170° C. for 2 h to obtain a shape memory polymer fiber;

[0050] (4) The shape memory polymer fiber is crystallized by self-nucleation to expand the melting transition temperature range. First, the shape memory polymer fiber is placed at 100°C and kept warm for 5 minutes to eliminate the initial thermal history. Second, it is stretched and cooled to -15°C for shaping and kept for 5 minutes to obtain a standard crystal state. Then, it is heated from -15°C to a selected self-nucleation temperature of 50°C (Ts) and kept for 5 minutes to partially melt. Finally, it is cooled to -15°C for self-nucleation crystallization to obtain a polymer fiber with thermal response.

[0051] (5) The thermally responsive polymer fiber is combined with 87texX5 cotton yarn with good hygroscopicity, and the two are composited and twisted on a hand-woven loom in a plain weave manner, with 3 cotton yarns twisted together and a twist point spacing of 6 mm to construct a primary fabric;

[0052] (6) Using a handheld spray brush, spray three layers of 1 wt% sodium methyl silicate waterproofing agent on the primary fabric for hydrophobic treatment, with a spraying amount of 10 g / m 2 , obtaining a fabric with thermal response and unidirectional moisture conduction.

[0053] Example 2

[0054] A method for preparing a fabric having thermal response and unidirectional moisture conductivity comprises the following steps:

[0055] (1) First, 25 wt% of ethylene-vinyl acetate copolymer was dissolved in chloroform in a weight ratio of 3:8 between dicumyl peroxide and ethylene-vinyl acetate copolymer. The dissolution process was performed by heating in a 55°C water bath and stirring at 180 rpm for 3 hours to obtain a chloroform solution of ethylene-vinyl acetate copolymer. Then, 3 wt% of dicumyl peroxide was added to the chloroform solution of ethylene-vinyl acetate copolymer, and heating and stirring were continued at 55°C for 1 hour. Finally, the mixed solution was inverted into a glass dish and the solvent was evaporated and dried at room temperature for 3 days to obtain a mixture.

[0056] (2) using a micro single-screw extruder to produce polymer fibers with a diameter of 1 mm at 60° C. and a rotation speed of 300 r / min;

[0057] (3) thermally crosslinking the polymer fiber in an oven at 170° C. for 2 h to obtain a shape memory polymer fiber;

[0058] (4) The shape memory polymer fiber is crystallized by self-nucleation to expand the melting transition temperature range. First, the shape memory polymer fiber is placed at 100°C and kept warm for 5 minutes to eliminate the initial thermal history. Second, it is stretched and cooled to -15°C for shaping and kept for 5 minutes to obtain a standard crystal state. Then, it is heated from -15°C to a selected self-nucleation temperature of 50°C (Ts) and kept for 5 minutes to partially melt. Finally, it is cooled to -15°C for self-nucleation crystallization to obtain a polymer fiber with thermal response.

[0059] (5) The thermally responsive polymer fiber is combined with 87texX5 cotton yarn with good hygroscopicity, and the two are composited and twisted on a hand-woven loom in a plain weave manner, with 3 cotton yarns twisted together and a twist point spacing of 6 mm to construct a primary fabric;

[0060] (6) Using a handheld spray brush, spray three layers of sodium methyl silicate waterproofing agent with a mass concentration of 0.5wt% on the primary fabric for hydrophobic treatment, with a spraying amount of 10g / m 2 , obtaining a fabric with thermal response and unidirectional moisture conduction.

[0061] Example 3

[0062] A method for preparing a fabric having thermal response and unidirectional moisture conductivity comprises the following steps:

[0063] (1) First, 25 wt% of ethylene-vinyl acetate copolymer was dissolved in chloroform in a weight ratio of 3:8 between dicumyl peroxide and ethylene-vinyl acetate copolymer. The dissolution process was performed by heating in a 55°C water bath and stirring at 180 rpm for 3 hours to obtain a chloroform solution of ethylene-vinyl acetate copolymer. Then, 3 wt% of dicumyl peroxide was added to the chloroform solution of ethylene-vinyl acetate copolymer, and heating and stirring were continued at 55°C for 1 hour. Finally, the mixed solution was inverted into a glass dish and the solvent was evaporated and dried at room temperature for 3 days to obtain a mixture.

[0064] (2) using a micro single-screw extruder to produce polymer fibers with a diameter of 1 mm at 60° C. and a rotation speed of 300 r / min;

[0065] (3) thermally crosslinking the polymer fiber in an oven at 170° C. for 2 h to obtain a shape memory polymer fiber;

[0066] (4) The shape memory polymer fiber is crystallized by self-nucleation to expand the melting transition temperature range. First, the shape memory polymer fiber is placed at 100°C and kept warm for 5 minutes to eliminate the initial thermal history. Second, it is stretched and cooled to -15°C for shaping and kept for 5 minutes to obtain a standard crystal state. Then, it is heated from -15°C to a selected self-nucleation temperature of 50°C (Ts) and kept for 5 minutes to partially melt. Finally, it is cooled to -15°C for self-nucleation crystallization to obtain a polymer fiber with thermal response.

[0067] (5) The thermally responsive polymer fiber is combined with 87texX5 cotton yarn with good hygroscopicity, and the two are composited and twisted on a hand-woven loom in a plain weave manner, with 3 cotton yarns twisted together and a twist point spacing of 6 mm to construct a primary fabric;

[0068] (6) Using a handheld spray brush, spray three layers of sodium methyl silicate waterproofing agent with a mass concentration of 1.5 wt% on the primary fabric for hydrophobic treatment, with a spraying amount of 10 g / m 2 , obtaining a fabric with thermal response and unidirectional moisture conduction.

[0069] Example 4

[0070] A method for preparing a fabric having thermal response and unidirectional moisture conductivity comprises the following steps:

[0071] (1) First, 25 wt% of ethylene-vinyl acetate copolymer was dissolved in chloroform in a weight ratio of 3:8 between dicumyl peroxide and ethylene-vinyl acetate copolymer. The dissolution process was performed by heating in a 55°C water bath and stirring at 180 rpm for 3 hours to obtain a chloroform solution of ethylene-vinyl acetate copolymer. Then, 3 wt% of dicumyl peroxide was added to the chloroform solution of ethylene-vinyl acetate copolymer, and heating and stirring were continued at 55°C for 1 hour. Finally, the mixed solution was inverted into a glass dish and the solvent was evaporated and dried at room temperature for 3 days to obtain a mixture.

[0072] (2) using a micro single-screw extruder to produce polymer fibers with a diameter of 1 mm at 60° C. and a rotation speed of 300 r / min;

[0073] (3) thermally crosslinking the polymer fiber in an oven at 170° C. for 2 h to obtain a shape memory polymer fiber;

[0074] (4) The shape memory polymer fiber is crystallized by self-nucleation to expand the melting transition temperature range. First, the shape memory polymer fiber is placed at 100°C and kept warm for 5 minutes to eliminate the initial thermal history. Second, it is stretched and cooled to -15°C for shaping and kept for 5 minutes to obtain a standard crystal state. Then, it is heated from -15°C to a selected self-nucleation temperature of 50°C (Ts) and kept for 5 minutes to partially melt. Finally, it is cooled to -15°C for self-nucleation crystallization to obtain a polymer fiber with thermal response.

[0075] (5) The thermally responsive polymer fiber is combined with 87texX5 cotton yarn with good hygroscopicity, and the two are composited and twisted on a hand-woven loom in a plain weave manner, with 3 cotton yarns twisted together and a twist point spacing of 6 mm to construct a primary fabric;

[0076] (6) Using a handheld spray brush, spray three layers of sodium methyl silicate waterproofing agent with a mass concentration of 2 wt% on the primary fabric for hydrophobic treatment, with a spraying amount of 10 g / m 2 , obtaining a fabric with thermal response and unidirectional moisture conduction.

[0077] Example 5

[0078] A method for preparing a fabric having thermal response and unidirectional moisture conductivity comprises the following steps:

[0079] (1) First, 25 wt% of ethylene-vinyl acetate copolymer was dissolved in chloroform in a weight ratio of 3:4 between dicumyl peroxide and ethylene-vinyl acetate copolymer. The dissolution process was performed by heating in a 45°C water bath and stirring at 180 rpm for 3 hours to obtain a chloroform solution of ethylene-vinyl acetate copolymer. Then, 3 wt% of dicumyl peroxide was added to the chloroform solution of ethylene-vinyl acetate copolymer, and heating and stirring were continued at 45°C for 1 hour. Finally, the mixed solution was inverted into a glass dish and the solvent was evaporated and dried at room temperature for 3 days to obtain a mixture.

[0080] (2) using a micro single-screw extruder to produce polymer fibers with a diameter of 0.5 mm at 100° C. and a rotation speed of 200 r / min;

[0081] (3) thermally crosslinking the polymer fiber in an oven at 150° C. for 1 hour to obtain a shape memory polymer fiber;

[0082] (4) The shape memory polymer fiber is crystallized by self-nucleation to expand the melting transition temperature range. First, the shape memory polymer fiber is placed at 90°C and kept warm for 15 minutes to eliminate the initial thermal history. Second, the fiber is stretched and cooled to -5°C for shaping and kept for 15 minutes to obtain a standard crystal state. The fiber is then heated from -15°C to a selected self-nucleation temperature of 50°C (Ts) and kept for 15 minutes to partially melt. Finally, the fiber is cooled to -5°C and kept for 10 minutes for self-nucleation crystallization to obtain a polymer fiber with thermal response.

[0083] (5) The thermally responsive polymer fiber is combined with 87texX5 cotton yarn with good hygroscopicity, and the two are composite twisted and braided on a hand-woven loom in a plain weave manner, with two cotton yarns twisted together and a twist point spacing of 3 mm to construct a primary fabric;

[0084] (6) Using a handheld spray brush, spray a layer of sodium methyl silicate waterproofing agent with a mass concentration of 1.5wt% on the primary fabric for hydrophobic treatment, with a spraying amount of 5g / m 2 , obtaining a fabric with thermal response and unidirectional moisture conduction.

[0085] Example 6

[0086] A method for preparing a fabric having thermal response and unidirectional moisture conductivity comprises the following steps:

[0087] (1) First, 25 wt% of ethylene-vinyl acetate copolymer was dissolved in chloroform in a weight ratio of 1:1 between dicumyl peroxide and ethylene-vinyl acetate copolymer. The dissolution process was performed by heating in a 50°C water bath and stirring at 180 rpm for 3 hours to obtain a chloroform solution of ethylene-vinyl acetate copolymer. Then, 3 wt% of dicumyl peroxide was added to the chloroform solution of ethylene-vinyl acetate copolymer, and heating and stirring were continued at 50°C for 1 hour. Finally, the mixed solution was inverted into a glass dish, and the solvent was evaporated and dried at room temperature for 3 days to obtain a mixture.

[0088] (2) using a micro single-screw extruder to produce polymer fibers with a diameter of 0.5 mm at 80° C. and a rotation speed of 400 r / min;

[0089] (3) thermally crosslinking the polymer fiber in an oven at 160° C. for 3 h to obtain a shape memory polymer fiber;

[0090] (4) The shape memory polymer fiber is subjected to a self-nucleation crystallization method to expand the melting transition temperature range. First, the shape memory polymer fiber is placed at 110°C and kept warm for 10 minutes to eliminate the initial thermal history. Second, the fiber is stretched and cooled to -10°C for shaping and kept for 10 minutes to obtain a standard crystal state. The fiber is then heated from -10°C to a selected self-nucleation temperature of 50°C (Ts) and kept for 10 minutes to partially melt. Finally, the fiber is cooled to -10°C and kept for 45 minutes for self-nucleation crystallization to obtain a polymer fiber with thermal response.

[0091] (5) The thermally responsive polymer fiber is combined with 87texX5 cotton yarn with good hygroscopicity, and the two are composite twisted and braided on a hand knitting machine using a plain weave method, with 4 cotton yarn twist groups and a twist point spacing of 9 mm to construct a primary fabric;

[0092] (6) Using a handheld spray brush, spray 5 layers of sodium methyl silicate waterproofing agent with a mass concentration of 0.1wt% on the primary fabric for hydrophobic treatment, with a spraying amount of 10g / m 2 , obtaining a fabric with thermal response and unidirectional moisture conduction.

[0093] Example 7

[0094] A method for preparing a fabric having thermal response and unidirectional moisture conductivity comprises the following steps:

[0095] (1) First, 25 wt% of ethylene-vinyl acetate copolymer was dissolved in chloroform in a weight ratio of 1:2 between dicumyl peroxide and ethylene-vinyl acetate copolymer. The dissolution process was performed by heating in a 60°C water bath and stirring at 180 rpm for 3 hours to obtain a chloroform solution of ethylene-vinyl acetate copolymer. Then, 3 wt% of dicumyl peroxide was added to the chloroform solution of ethylene-vinyl acetate copolymer, and heating and stirring were continued at 60°C for 1 hour. Finally, the mixed solution was inverted into a glass dish, and the solvent was evaporated and dried at room temperature for 3 days to obtain a mixture.

[0096] (2) using a micro single-screw extruder to produce polymer fibers with a diameter of 1.5 mm at 70° C. and a rotation speed of 200 r / min;

[0097] (3) thermally crosslinking the polymer fiber in an oven at 150° C. for 2 h to obtain a shape memory polymer fiber;

[0098] (4) The shape memory polymer fiber is subjected to a self-nucleation crystallization method to expand the melting transition temperature range. First, the shape memory polymer fiber is placed at 100°C and kept warm for 10 minutes to eliminate the initial thermal history. Second, the fiber is stretched and cooled to -10°C for shaping and kept for 10 minutes to obtain a standard crystal state. The fiber is then heated from -10°C to a selected self-nucleation temperature of 50°C (Ts) and kept for 10 minutes to partially melt. Finally, the fiber is cooled to -15°C and kept for 20 minutes for self-nucleation crystallization to obtain a polymer fiber with thermal response.

[0099] (5) The thermally responsive polymer fiber is combined with 87texX5 cotton yarn with good hygroscopicity, and the two are composited and twisted on a hand-woven loom in a plain weave manner, with 3 cotton yarns twisted together and a twist point spacing of 6 mm to construct a primary fabric;

[0100] (6) Using a handheld spray brush, spray three layers of sodium methyl silicate waterproofing agent with a mass concentration of 2 wt% on the primary fabric for hydrophobic treatment, with a spraying amount of 15 g / m 2 , obtaining a fabric with thermal response and unidirectional moisture conduction.

[0101] Example 8

[0102] A method for preparing a fabric having thermal response and unidirectional moisture conductivity comprises the following steps:

[0103] (1) First, 25 wt% of ethylene-vinyl acetate copolymer was dissolved in chloroform in a weight ratio of 3:5 between dicumyl peroxide and ethylene-vinyl acetate copolymer. The dissolution process was performed by heating in a water bath at 45-6055°C and stirring at 180 rpm for 3 hours to obtain a chloroform solution of ethylene-vinyl acetate copolymer. Then, 3 wt% of dicumyl peroxide was added to the chloroform solution of ethylene-vinyl acetate copolymer, and heating and stirring were continued at 55°C for 1 hour. Finally, the mixed solution was inverted into a glass dish, and the solvent was evaporated and dried at room temperature for 3 days to obtain a mixture.

[0104] (2) using a micro single-screw extruder to produce polymer fibers with a diameter of 1 mm at 90° C. and a rotation speed of 400 r / min;

[0105] (3) thermally crosslinking the polymer fiber in an oven at 160° C. for 1 hour to obtain a shape memory polymer fiber;

[0106] (4) The shape memory polymer fiber is subjected to a self-nucleation crystallization method to expand the melting transition temperature range. First, the shape memory polymer fiber is placed at 100°C and kept warm for 15 minutes to eliminate the initial thermal history. Second, the fiber is stretched and cooled to -15°C for shaping, and kept for 15 minutes to obtain a standard crystal state. The fiber is then heated from -15°C to a selected self-nucleation temperature of 50°C (Ts) and kept for 15 minutes to partially melt. Finally, the fiber is cooled to -15°C and kept for 30 minutes for self-nucleation crystallization to obtain a polymer fiber with thermal response.

[0107] (5) The thermally responsive polymer fiber is combined with 87texX5 cotton yarn with good hygroscopicity, and the two are composite twisted and braided on a hand-woven loom in a plain weave manner, with two cotton yarns twisted together and a twist point spacing of 3 mm to construct a primary fabric;

[0108] (6) Using a handheld spray brush, spray 5 layers of sodium methyl silicate waterproofing agent with a mass concentration of 0.5wt% on the primary fabric for hydrophobic treatment, with a spraying amount of 10g / m 2 , obtaining a fabric with thermal response and unidirectional moisture conduction.

[0109] In order to further illustrate the technical effects of the present invention, the present invention is also provided with comparative examples, as follows:

[0110] Comparative Example 1

[0111] Compared with Example 1, the difference is that no sodium methyl silicate waterproofing agent is used for hydrophobic treatment.

[0112] A method for preparing a thermally responsive fabric comprises the following steps:

[0113] (1) First, 25 wt% of ethylene-vinyl acetate copolymer was dissolved in chloroform in a weight ratio of 3:8 between dicumyl peroxide and ethylene-vinyl acetate copolymer. The dissolution process was performed by heating in a 55°C water bath and stirring at 180 rpm for 3 hours to obtain a chloroform solution of ethylene-vinyl acetate copolymer. Then, 3 wt% of dicumyl peroxide was added to the chloroform solution of ethylene-vinyl acetate copolymer, and heating and stirring were continued at 55°C for 1 hour. Finally, the mixed solution was inverted into a glass dish and the solvent was evaporated and dried at room temperature for 3 days to obtain a mixture.

[0114] (2) using a micro single-screw extruder to produce polymer fibers with a diameter of 1 mm at 60° C. and a rotation speed of 300 r / min;

[0115] (3) thermally crosslinking the polymer fiber in an oven at 170° C. for 2 h to obtain a shape memory polymer fiber;

[0116] (4) The shape memory polymer fiber is crystallized by self-nucleation to expand the melting transition temperature range. First, the shape memory polymer fiber is placed at 100°C and kept warm for 5 minutes to eliminate the initial thermal history. Second, it is stretched and cooled to -15°C for shaping and kept for 5 minutes to obtain a standard crystal state. Then, it is heated from -15°C to a selected self-nucleation temperature of 50°C (Ts) and kept for 5 minutes to partially melt. Finally, it is cooled to -15°C for self-nucleation crystallization to obtain a polymer fiber with thermal response.

[0117] (5) The thermally responsive polymer fiber is combined with 87texX5 cotton yarn with good hygroscopicity, and the two are compositely twisted and woven on a hand-woven loom in a plain weave manner. Three cotton yarns are twisted together, and the twist point spacing is 6 mm to construct a primary fabric, i.e., a thermally responsive fabric.

[0118] The fabrics prepared in Examples 1 to 8 and Comparative Example 1 were tested for performance. The unidirectional moisture conduction, water evaporation rate, and wettability were tested according to GB / T 21655.1-2008. The thermal conductivity and infrared thermal imaging were tested according to GB / T 41560-2022. The results are as follows:

[0119] 1. One-way moisture conduction performance

[0120] The unidirectional moisture conductivity of the fabrics prepared in the examples of the present invention and the comparative examples is as follows: Figure 1 and Figure 2 As shown by Figure 1 It can be seen that: the fabric in Comparative Example 1 that was not sprayed with sodium methyl silicate solution had a negative unidirectional moisture conduction test index, indicating that the original cotton fabric did not have the ability to conduct moisture in a unidirectional manner; Figure 2 It can be seen that after spraying 1wt% sodium methyl silicate solution, the one-way moisture conduction index (191.79) and the dynamic integrated transport index (OMMC) are the highest, and the one-way moisture conduction performance is significant.

[0121] 2. Wettability test

[0122] The surface wettability of the fabrics prepared in the examples of the present invention and the comparative examples is as follows: Figure 3 As shown by Figure 3 It can be seen that: in the comparative example, the methylene blue droplets on the surface of the fabric without hydrophobic treatment spread quickly on the fabric, showing strong hydrophilicity, and the surface of the fabric after hydrophobic treatment showed a unidirectional moisture conduction function, and the droplets showed rapid penetration.

[0123] 3. Water evaporation rate

[0124] According to GB / T 21655.1-2008 standard, the water evaporation rate of the fabrics prepared in Example 1 and Comparative Example 1 was tested. Figure 4It can be seen that the water evaporation amount of the fabric prepared in the embodiment of the present invention increases rapidly within 40 minutes and then tends to slow down. According to the curve calculation, the water evaporation rate of the thermally responsive and unidirectional moisture conductive fabric of the present invention is about 0.38 g / h, which has good water volatilization ability.

[0125] 4. Thermal conductivity

[0126] The responsive thermal management performance of the fabric with thermal response and unidirectional moisture conductivity prepared by the present invention is as follows: Figure 5 and Figure 6 As shown, at a response temperature of 48°C, when the pores were at their maximum, the fabric's thermal conductivity was 0.0889 W / m·K and its air permeability was 461.7 mm / s. Subsequently, as the temperature decreased, the pores gradually decreased, ultimately returning the thermal conductivity to 0.0851 W / m·K and the air permeability to 439.8 mm / s. This demonstrates that the thermally responsive and unidirectionally moisture-conductive fabric prepared by this invention possesses excellent dynamic responsive thermal conductivity control capabilities. The thermal conductivity of the fabric does not change significantly before and after surface treatment, and the presence of the hydrophobic layer has little impact on the responsive thermal management performance of the shape memory fabric.

[0127] 5. Infrared thermal imaging

[0128] Figure 7 The infrared thermal imaging image of the fabric with thermal response and unidirectional moisture conduction prepared by the present invention as the temperature changes. Figure 7 It can be seen that: as the temperature continues to rise, the pores between the yarns continue to expand, and the radiation transmittance of the fabric increases; during the shape recovery process, the pores of the fabric gradually become smaller, and the radiation transmittance gradually decreases, showing a significant responsive heat and moisture management function.

[0129] In summary, the present invention utilizes a responsive functional coating and a responsive fabric structure to create a shape-memory material with thermal responsiveness and unidirectional moisture conduction. This material can react to external stimuli, such as heat and humidity, and undergo corresponding morphological changes. The thermally responsive and unidirectional moisture conduction fabric prepared by the present invention offers advantages such as low cost, ease of processing, and high deformation capacity, and holds great promise in the field of intelligent heat and moisture management fabrics.

[0130] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a fabric having thermal response and unidirectional moisture conductivity, characterized in that: The following steps are involved: Dissolving dicumyl peroxide in a chloroform solution of ethylene-vinyl acetate copolymer, removing the solvent to obtain a mixture, extruding the mixture to obtain polymer fibers, thermally crosslinking the polymer fibers at 150-170° C. to obtain shape memory polymer fibers having a network structure, and subjecting the shape memory polymer fibers to self-nucleation crystallization to obtain polymer fibers having thermal response; the weight ratio of dicumyl peroxide to ethylene-vinyl acetate copolymer is 3-4:4-8; the self-nucleation crystallization is specifically as follows: treating the shape memory polymer fibers at 90-110° C. for 5-15 minutes; cooling and shaping at -5--15° C. for 5-15 minutes, maintaining at 50° C. for 5-15 minutes, cooling to -5--15° C., and maintaining for 10-45 minutes for self-nucleation crystallization; Using cotton fibers and the shape memory polymer fibers for composite twist weaving in a plain weave manner to obtain a primary fabric; The primary fabric is sprayed with a sodium methyl silicate waterproofing agent for hydrophobic treatment to obtain a fabric with thermal response and unidirectional moisture conductivity.

2. The preparation method according to claim 1, characterized in that The mass concentration of the sodium methyl silicate waterproofing agent is 0.1-3wt%, and the spraying amount is 5-20g / m 2 .

3. The preparation method according to claim 2, characterized in that The number of spraying is 1 to 5 times.

4. The preparation method according to claim 1, characterized in that The thermal crosslinking time is 1 to 3 hours.

5. The preparation method according to claim 1, characterized in that A single-screw extruder is used for extrusion, and the extrusion process parameters are: extrusion temperature 60-100° C., rotation speed 200-400 r / min, and extrusion diameter 0.5-2 mm.

6. The preparation method according to claim 1, characterized in that The conditions for the composite twisted braiding are: using 2 to 4 cotton yarn twist groups, and the twist point spacing is 3 to 9 mm.

7. The preparation method according to claim 1, characterized in that The preparation method of the chloroform solution of the ethylene-vinyl acetate copolymer is as follows: 4 to 8 parts by weight of ethylene-vinyl acetate copolymer particles are added to 96 to 92 parts of chloroform solution at 45 to 60° C., and stirred at 150 to 200 r / min for 2 to 6 hours; when the dicumyl peroxide is dissolved, 3 to 4 parts by weight of dicumyl peroxide powder are added to 97 to 96 parts of the chloroform solution of the ethylene-vinyl acetate copolymer at 45 to 60° C., stirred at 150 to 200 r / min for 1 to 4 hours, and then kept at room temperature for 2 to 6 days.

8. A fabric with thermal response and unidirectional moisture conductivity prepared by the preparation method according to any one of claims 1 to 7.

Images