High-elasticity composite yarn with electrocaloric multistage color-changing performance and preparation method and application thereof

Abstract

The application provides a high-elastic composite yarn with electrocaloric multistage color-changing performance and a preparation method and application thereof. Through external circuit control of current, the yarn can be precisely and quickly heated to a specific color-changing temperature point, so that programmed multistage color switching is realized. The cladding structure of the conductive component and the base yarn designed in the application enhances the mechanical protection of the conductive body, avoids the fracture caused by friction and bending in subsequent processing and use, and ensures the long-term stability of the conductive heating. The high-elastic composite yarn provided by the application has stable structure, rich color-changing effect, strong process adaptability, is suitable for large-scale production, and has a wide application prospect in the fields of intelligent wearing, dynamic camouflage, human-computer interaction and safety warning.

Description

Technical Field

[0001] This invention belongs to the field of spinning and processing technology, specifically relating to a high-elastic composite yarn with electrothermal multi-stage color-changing properties, its preparation method, and its application. Background Technology

[0002] Conductive yarn, as a functional textile material, has broad application prospects. Combining conductive heat-generating materials with thermochromic materials can produce fibers, yarns, or fabrics with electrothermal color-changing properties, providing more possibilities for the development of intelligent color-changing textiles.

[0003] However, existing electrothermal color-changing textiles still generally face two major technical limitations: (1) Single color-changing level: Most products can only achieve "colored-colorless" or reversible switching between two colors. The color-changing effect is monotonous and the information carrying capacity is limited. It cannot meet the needs of dynamic camouflage, high-level information encoding and other scenarios for multi-level, continuous and rich color changes.

[0004] (2) Passive control method: Traditional thermochromic materials mainly rely on changes in ambient temperature or human body temperature to trigger color change. The response speed is slow and it cannot achieve active, precise and on-demand programmed control, which limits its application in scenarios that require real-time interaction and intelligent feedback.

[0005] Chinese invention patent application number CN202410707815.7 discloses a fever-inducing color-changing warning sock, in which the temperature-sensing layer forms a tight fit at the sock's ankle for real-time monitoring; at the same time, the heat-conducting layer and the heat-insulating layer form a physical clamping and encapsulation structure to protect the fixation and long-lasting effect of the color-changing powder.

[0006] Chinese invention patent application number CN202311305266.2 discloses a smart textile, in which a first conductive yarn woven along the weft direction is used to generate heat when the electrode is energized, causing the temperature of the textile to change; a thermochromic yarn is used to present different colors according to the temperature change of the smart textile; and a polymer optical fiber is used to present the color of the light emitted by the light source device.

[0007] Chinese invention patent application number CN202510708019.X discloses a cool-feeling nylon-based color-changing fabric and its preparation method. The fabric is composed of nylon-based cool-feeling fibers and thermochromic fibers, with a contact coolness index Q-max greater than 0.25 J / (cm2·s). The thermochromic fibers are loaded with optimized thermochromic microcapsules, with a color-changing temperature range of 18.5~43.5℃. A wider temperature response and rapid color-changing performance can be achieved by adjusting the microcapsule structure.

[0008] In summary, most existing technologies can only achieve single-color or dual-color switching, with limited color-changing levels, and the color-changing process mostly depends on passive environmental temperature changes, making it impossible to achieve active, precise, and rapid programmed electronic control. Summary of the Invention

[0009] In view of the problems of limited color-changing levels, poor comfort, and low color-changing sensitivity in existing technologies, the purpose of this invention is to provide a high-elastic composite yarn with electrothermal multi-level color-changing properties, its preparation method, and its application, so as to obtain an intelligent color-changing yarn that simultaneously meets five major requirements: active electronic control, multi-level color changing, wearing comfort, structural stability, and simple process.

[0010] The present invention solves the technical problem by adopting the following technical solution: This invention provides a method for preparing a high-elastic composite yarn with electrothermal multi-stage color-changing properties, comprising the following steps: Step 1: Using a hollow spindle spinning machine, the first base yarn is spirally wound onto the surface of the conductive component. The overfeed ratio is set to achieve full coverage of the conductive component by the first base yarn (coverage rate ≥ 100%), thus obtaining conductive core-spun yarn. Step 2: Combine the conductive core-spun yarn with the second base yarn and the elastic component to weave together to form a composite yarn; Step 3: Premix different thermochromic dyes to achieve the desired thermochromic effect; Step 4: The composite yarn is dyed with a mixed thermochromic dye to obtain a high-elastic composite yarn with electrothermal multi-stage color-changing properties.

[0011] The present invention also provides a high-elastic composite yarn with electrothermal multi-stage color-changing properties prepared according to the above preparation method, comprising: a conductive component for conducting electricity when a voltage is applied to generate a Joule heating effect; a base yarn for providing hygroscopicity, dyeability, and hand feel while mechanically protecting the conductive component; and an elastic filament for imparting the necessary elasticity to the composite yarn.

[0012] The present invention also provides the application of the above-mentioned composite yarn or the composite yarn obtained by the above preparation method in smart wearables, dynamic camouflage, human-computer interaction and security early warning.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. Active and precise multi-stage electronically controlled color change: By controlling the current through an external circuit, the yarn can be heated to a specific color change temperature point in a precise and rapid manner, thereby realizing a programmed multi-stage color switching.

[0014] 2. Stable and reliable structure: The coating structure of the conductive components and the base yarn enhances the mechanical protection of the conductor, avoiding breakage caused by friction and bending during subsequent processing and use, and ensuring the long-term stability of conductive heating.

[0015] 3. Excellent performance: The outer base yarn provides excellent moisture absorption, dyeability and hand feel; the inner elastic filament gives the composite yarn the necessary elasticity, so that the final fabric has both intelligent color-changing function and good wearing comfort and fit.

[0016] 4. Simple process, suitable for mass production: The entire preparation process only involves conventional twisting, wrapping and low-temperature dyeing processes, without the need for complex equipment or harsh conditions. It is highly compatible with the existing textile industry chain and has the potential for large-scale production. Attached Figure Description

[0017] Figure 1 The images show the color change effect of the composite yarn in the test example of this application at different temperatures. Detailed Implementation

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] This application provides a method for preparing a high-elastic composite yarn with electrothermal multi-stage color-changing properties, including the following steps: Step 1: Using a hollow spindle spinning machine, the first base yarn is spirally wound onto the surface of the conductive component. The overfeed ratio is set to achieve full coverage of the conductive component by the first base yarn, thus obtaining conductive core-spun yarn.

[0020] Step 2: Combine the conductive core-spun yarn with the second base yarn and the elastic component to weave together to form a composite yarn.

[0021] Step 3: Premix different thermochromic dyes to achieve the desired thermochromic effect.

[0022] Step 4: The composite yarn is dyed with a mixed thermochromic dye to obtain a high-elastic composite yarn with electrothermal multi-stage color-changing properties.

[0023] Furthermore, when the coverage rate of the conductive core-spun yarn is 100%, the first base yarn provides a uniform, full coverage of the conductive component, with no conductive yarn exposed on the surface. When the coverage rate is greater than 100%, the first base yarn provides a non-uniform, super-coverage of the conductive component, resulting in decorative effects such as knots and loops on the surface. This design of the first base yarn's coverage structure effectively improves comfort, safety, abrasion resistance, durability, and stability during use when in contact with the human body.

[0024] Furthermore, step 3 specifically involves: according to the color mixing principle, adjusting the colors from C1 to C... n (C represents the color type) and the corresponding color temperature is T1~T n (T is the color-changing temperature) dyes are premixed in proportion to form color C according to the required color-changing effect. 1～n A mixture of dyes. Dye C... n The strain color temperature is T n Color C 1～n For dyes C1~C n A mixture of colors.

[0025] This application also provides a high-elastic composite yarn with electrothermal multi-stage color-changing properties, obtained according to the above preparation method, comprising: The conductive component is used to conduct electricity when a voltage is applied, generating a Joule heating effect; the base yarn is used to provide hygroscopicity, dyeability, and hand feel while mechanically protecting the conductive component; and the elastic filament is used to give the composite yarn the necessary elasticity.

[0026] Furthermore, applying a voltage of 1V to 10V to the composite yarn will cause a temperature rise due to the Joule heating effect generated by the conductive components, specifically: When the temperature reaches T1, dye C1 changes from its original color to white, and the composite yarn exhibits a first-order color change effect, from color C... 1～n Change color to C 2～n (i.e., from dyes C1 to C) n The mixed color changes of the dyes are C2 to C3. n (mixed colors) When the temperature reaches T2, both dyes C1 and C2 change from their original color to white, and the composite yarn exhibits a second-order color change effect, from color C... 1～n Change color to C 3～n (i.e., from dyes C1 to C) n The mixed color changes of the dyes are C3~C n (mixed colors) When the temperature reaches T i At that time, dye C1~C i All colors change due to the dye, exhibiting an i-order color change effect, with color C... i～n Change color to C i+1～n Where 1≤i+1≤n; And so on, when the temperature reaches T n At that time, dye C1~C n All colors change from dye to white, and the composite yarn exhibits an n-order color change effect, from color C... 1～n The color changes to white (i.e., from dye C1 to C1). n The mixed color changes to white.

[0027] Furthermore, the color-changing effect of the composite yarn is reversible.

[0028] Specifically, the base yarn material is not limited, as long as it is dyeable; the conductive component is selected from yarns with conductive properties such as silver-plated filament, stainless steel yarn, or conductive carbon fiber yarn; the elastic component is elastic yarns such as spandex and Lycra (elongation ≥ 100%).

[0029] The composite yarn has an elastic elongation of ≥100% along its length, making it suitable for tensile strain sensors. It also has two sensing modes: electrical signal and color signal. The electrical signal sensing mode has high accuracy, while the color signal mode is more intuitive. These two modes can be mutually verified when used for monitoring physiological signals of human health or exercise.

[0030] Since the composite yarn can be driven to switch between different color states accurately and quickly through electronic control, the embodiments of this application also provide the application of the above-mentioned composite yarn in smart wearables, dynamic camouflage, human-computer interaction and security warning.

[0031] Based on the same concept as the above embodiments, the test examples of this application respectively use 32-count cotton yarn as the base yarn, stainless steel wire as the conductive component, and 840D spandex as the elastic component, providing a method for preparing a high-elastic composite yarn with electrothermal multi-stage color-changing properties. The specific steps are as follows: A hollow spindle spinning machine is used to spirally wrap cotton yarn around the surface of stainless steel wire. By setting the roller speed and nail rotation speed, 100% coating of the conductive components by the cotton yarn is achieved. The obtained conductive core-spun yarn is woven together with cotton yarn and spandex to form a composite yarn; The dyes were mixed uniformly in a volume ratio of C1:C2:C3:distilled water of 6:7:2:15; wherein dye C1 changed from red to colorless at a temperature T1=25℃, dye C2 changed from yellow to colorless at a temperature T2=34℃, and dye C3 changed from blue to colorless at a temperature T3=42℃. The composite yarn is dyed by immersion for 5-10 minutes, and then air-dried for another 5-10 minutes.

[0032] Applying a 5V voltage to the composite yarn yields the following result: Figure 1 The color-changing effect shown. (By...) Figure 1 It can be seen that, based on the Joule heating effect generated by the conductive components, when the temperature is below T1=25℃, the composite yarn exhibits a mixed color of dyes C1 to C3, i.e., brown; when the temperature is above T1=25℃, dye C1 changes from red to white, and the composite yarn exhibits a first-order color change effect, from color C... 1～3 Change color to C 2～3That is, the mixed color of dyes C1 to C3 changes from brown to green; when the temperature reaches T2=34℃, dyes C1 and C2 both change from their original color to white, and the composite yarn exhibits a second-order color change effect, from color C... 2～3 The color changes to C3 blue, meaning the mixture of dyes C1 to C3 changes to C3 blue. When the temperature reaches T3=42℃, all dyes C1 to C3 change from their original color to white, resulting in a three-stage color change effect in the composite yarn. 1～3 The color changes to white, meaning the mixture of dyes C1 to C3 changes from white. During the energizing process, the surface temperatures of the composite yarn, measured using an infrared thermal imager, were 24.5℃, 28.6℃, 34.6℃, and 42℃, indicating the Joule heating effect and temperature rise under a 5V voltage. Furthermore, the color change of the composite yarn is reversible.

[0033] The cotton yarn's coating structure for conductive components effectively enhances comfort, safety, abrasion resistance, durability, and stability during contact with the human body. This composite yarn exhibits an elastic elongation of ≥100% along its length, making it suitable for tensile strain sensors. It simultaneously supports both electrical and color signal sensing modes; the electrical signal mode offers high accuracy, while the color signal mode provides a more intuitive reading. These two modes can be mutually verified when monitoring physiological signals related to human health or movement. Through electronic control, the yarn can be precisely and rapidly switched between different color states, demonstrating broad application prospects in smart wearables, dynamic camouflage, human-computer interaction, and security early warning systems.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a high-elastic composite yarn with electrothermal multi-stage color-changing properties, characterized in that, Includes the following steps: Step 1: Using a hollow spindle spinning machine, the first base yarn is spirally wound onto the surface of the conductive component. The overfeed ratio is set to achieve full coverage of the conductive component by the first base yarn, thus obtaining conductive core-spun yarn. Step 2: Combine the conductive core-spun yarn with the second base yarn and the elastic component to weave together to form a composite yarn; Step 3: Premix different thermochromic dyes to achieve the desired thermochromic effect; Step 4: The composite yarn is dyed with a mixed thermochromic dye to obtain a high-elastic composite yarn with electrothermal multi-stage color-changing properties.

2. The method for preparing a high-elastic composite yarn with electrothermal multi-stage color-changing properties according to claim 1, characterized in that: When the coverage rate of the conductive core-spun yarn is 100%, the first base yarn has a uniform full coverage effect on the conductive component, and no conductive yarn is exposed on the surface. When the coating rate is greater than 100%, the first base yarn has an uneven super-coating effect on the conductive components, and the surface exhibits a fancy effect.

3. A method for preparing a high-elastic composite yarn with electrothermal multi-stage color-changing properties according to claim 1 or 2, characterized in that, Step 3 specifically involves: Based on color mixing principles, the color types are categorized as C1 to C2. n And the corresponding strain color temperature is T1~T n The dyes are premixed in proportion to form color C according to the required color effect. 1～n Mixed dyes; Among them, dye C n The strain color temperature is T n Color C 1～n For dyes C1~C n A mixture of colors.

4. A high-elastic composite yarn with electrothermal multi-stage color-changing properties, prepared by the method according to any one of claims 1 to 3, characterized in that, include: The conductive component is used to conduct electricity when a voltage is applied, generating a Joule heating effect; The base yarn is used to provide hygroscopicity, dyeability, and hand feel while mechanically protecting the conductive components; Elastic filaments are used to give composite yarns the necessary elasticity.

5. The high-elastic composite yarn with electrothermal multi-stage color-changing properties according to claim 4, characterized in that, The base yarn material is dyeable.

6. The high-elastic composite yarn with electrothermal multi-stage color-changing properties according to claim 5, characterized in that, When a voltage is applied, a heating effect occurs due to the Joule heating effect generated by the conductive components. When the temperature reaches T... i At that time, the dye C1~C i All colors change due to the dye, exhibiting an i-order color change effect, with color C... i～n Change color to C i+1～n Where 1≤i+1≤n.

7. The high-elastic composite yarn with electrothermal multi-stage color-changing properties according to claim 6, characterized in that, The color-changing effect of the composite yarn is reversible.

8. The application of a composite yarn prepared according to any one of claims 1-3 or the composite yarn as described in any one of claims 4-7 in smart wearables, dynamic camouflage, human-computer interaction and security early warning.

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