Temperature-sensitive color-changing silicone rubber fiber as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of temperature-sensitive color-changing materials, and particularly relates to a temperature-sensitive color-changing silicone rubber fiber as well as a preparation method and application thereof. The preparation method of the temperature-sensitive color-changing silicon rubber fiber comprises the following steps: mixing a silicon rubber prepolymer and a temperature-sensitive color-changing microcapsule to obtain a silicon rubber / temperature-sensitive color-changing microcapsule mixed prepolymer; and extruding the silicone rubber / temperature-sensitive color-changing microcapsule mixed prepolymer and a hydrogel precursor solution through a coaxial spinning device to obtain core-shell fibers which take the silicone rubber / temperature-sensitive color-changing microcapsule mixed prepolymer as an inner core and the hydrogel as an outer shell, putting the core-shell fibers into a coagulating bath solution, curing, and removing the shell to obtain the silicone rubber / temperature-sensitive color-changing microcapsule core-shell fiber. The core-shell fiber is obtained through coaxial spinning, the hydrogel provides shaping and protection for inner core curing, and the temperature-sensitive color-changing microcapsules exist in the fiber and are not prone to falling off, so that the fiber has the stable temperature-sensitive color-changing capacity and has the good mechanical property, heat resistance, solvent resistance and corrosion resistance; the comprehensive performance such as diversified temperature-sensitive discoloration capability is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of temperature-sensitive color-changing materials, and in particular relates to a temperature-sensitive color-changing silicone rubber fiber and a preparation method and application thereof. Background Art

[0002] Thermochromic materials, which change color in response to temperature fluctuations, hold great promise for applications in temperature sensors, smart packaging, and color-changing fabrics. Thermochromic microcapsules, as a thermochromic material, undergo a distinct color change near the color-changing temperature. When incorporated into other polymer matrices, they impart temperature-sensitive color-changing capabilities. Key to the development of these materials is ensuring that the polymer matrix protects the microcapsules, ensuring long-term and stable temperature-sensitive color change.

[0003] At present, thermochromic microcapsules are protected by processing thermochromic microcapsules / polymer composite materials into fibers, and the resulting thermochromic fibers have a wide range of uses. The fiber structure itself can give thermochromic fibers excellent deformability and mechanical strength, allowing them to be combined with fabrics by sewing, or directly obtain large-area fabrics by weaving. When they have the ability to change color sensitively, thermochromic fibers can enable fabrics to have functions such as temperature sensing, fashionable color change, and encrypted information display, and therefore have unique application value. Existing thermochromic fibers usually have a layer of thermochromic microcapsules adhered to the surface of various fibers. However, the thermochromic microcapsules are easy to fall off during daily use, resulting in the attenuation of their thermochromic ability. Alternatively, thermochromic microcapsules can be mixed into spinnable polymers and processed into thermochromic fibers through spinning technology. However, common spinnable polymers usually have poor tolerance to heat or chemical solvents, which affects the stability and weather resistance of their thermochromic ability.

[0004] Silicone rubber, an organosilicone polymer with excellent mechanical properties, heat resistance, solvent resistance, and corrosion resistance, is an ideal polymer matrix for the development of stable thermochromic fibers. However, due to its poor spinnability, silicone rubber-based functional fibers and mass production technologies are still lacking. The challenge is to combine silicone rubber with thermochromic microcapsules to create fibers suitable for thermochromic applications, and to optimize their structure, thermochromic behavior, and usage. Summary of the Invention

[0005] The present invention aims to address one or more technical problems existing in the aforementioned prior art and to provide at least a beneficial alternative. Specifically, the present invention provides a method for preparing temperature-sensitive color-changing silicone rubber fibers. The method combines silicone rubber with temperature-sensitive color-changing microcapsules and processes them into fibers. The fibers thus prepared achieve a temperature-sensitive color-changing effect and exhibit excellent mechanical properties, heat resistance, and corrosion resistance.

[0006] The inventive concept of the present invention is that the method for preparing the thermochromic silicone rubber fiber comprises the following steps: first, mixing a silicone rubber prepolymer and thermochromic microcapsules to produce a silicone rubber / thermochromic microcapsule mixed prepolymer; then, extruding the silicone rubber / thermochromic microcapsule mixed prepolymer and a hydrogel precursor solution through a coaxial spinning apparatus to produce core-shell fibers; then, placing the core-shell fibers in a coagulation bath solution, curing them, and de-shelling them to produce the thermochromic silicone rubber fiber. The present invention utilizes coaxial spinning technology to produce core-shell fibers with the silicone rubber / thermochromic microcapsule mixed prepolymer as the core and the hydrogel as the outer shell. The hydrogel provides shaping and protection for the core during curing, and then de-shelling is performed to produce the thermochromic silicone rubber fiber. Because the thermochromic microcapsules are present within the fiber and are not easily detached, the fiber exhibits stable thermochromic properties. Furthermore, the thermochromic silicone rubber fiber exhibits excellent elastomechanical properties, heat resistance, solvent resistance, corrosion resistance, and visually detectable and diverse thermochromic properties.

[0007] Therefore, a first aspect of the present invention provides a temperature-sensitive color-changing silicone rubber fiber.

[0008] Specifically, the preparation method of the temperature-sensitive color-changing silicone rubber fiber includes the following steps:

[0009] (1) mixing a silicone rubber prepolymer and a thermosensitive color-changing microcapsule to obtain a silicone rubber / thermosensitive color-changing microcapsule mixed prepolymer;

[0010] (2) The silicone rubber / thermochromic microcapsule mixed prepolymer and hydrogel precursor solution obtained in step (1) are extruded through a coaxial spinning device to obtain core-shell fibers with the silicone rubber / thermochromic microcapsule mixed prepolymer as the core and the hydrogel as the shell. The core-shell fibers are then placed in a coagulation bath solution, cured, and the shell removed to obtain the thermochromic silicone rubber fibers.

[0011] Specifically, the present invention prepares thermosensitive color-changing silicone rubber fibers by combining silicone rubber with thermosensitive color-changing microcapsules, and optimizes the process conditions in terms of silicone rubber type, added concentration of thermosensitive color-changing microcapsules, combination of multiple thermosensitive color-changing microcapsules, spinning parameters, fiber structure regulation, and fiber usage method, so that the combination and spinning of the two components becomes feasible, and functional fibers based on silicone rubber are successfully obtained.

[0012] Preferably, in step (1), the silicone rubber prepolymer and the thermochromic microcapsules are mixed by physical stirring.

[0013] Preferably, in step (1), the silicone rubber prepolymer includes at least one of a single-component silicone rubber prepolymer and a two-component cross-linked silicone rubber prepolymer.

[0014] Preferably, the silicone rubber prepolymer includes at least one of polydimethylsiloxane, condensation-type silicone rubber, addition-type silicone rubber, and mold silicone.

[0015] Specifically, the present invention requires the selection of a silicone rubber prepolymer that is colorless, transparent, or translucent (1mm transmittance greater than 50%), has a cross-linking temperature of less than 150°C, a viscosity before cross-linking less than 1000 Pa·s, a tensile strain at break greater than 200% after cross-linking, and does not contain silica. Colorless silicone rubber will not affect the hue after adding thermochromic microcapsules; the better the transparency of the silicone rubber prepolymer, the higher the color saturation after mixing with the same concentration of thermochromic microcapsules. The cross-linking temperature of the silicone rubber prepolymer must be lower than the temperature tolerance of the thermochromic microcapsules. The higher the tensile strain at break after cross-linking, the more favorable it is for the deformability and weavability of the thermochromic fiber. Silicone rubber with too high a viscosity before cross-linking is not conducive to smooth extrusion during spinning. Silicone rubber compounds with added silica have extremely high viscosity and reduced transmittance and are not suitable for the present invention. In addition, waterproofness, heat resistance, solvent resistance, and corrosion resistance are common characteristics of silicone rubber and do not require special requirements.

[0016] Preferably, in step (1), the thermosensitive color-changing microcapsules include one or more thermosensitive color-changing microcapsules, which are also called thermochromic powder or temperature-changing powder.

[0017] Preferably, the number of the thermosensitive color-changing microcapsules is greater than or equal to 1 and less than 5.

[0018] Specifically, according to the performance of the thermosensitive color-changing silicone rubber fiber and the requirements for the thermosensitive color-changing ability, a silicone rubber prepolymer with specific properties and one or more thermosensitive color-changing microcapsules are selected.

[0019] Preferably, in step (1), the content of the thermosensitive color-changing microcapsules in the silicone rubber / thermosensitive color-changing microcapsule mixed prepolymer is 1 wt% to 15 wt%. As the concentration of the thermosensitive color-changing microcapsules increases, the color saturation of the thermosensitive color-changing silicone rubber fiber increases accordingly.

[0020] Specifically, when the concentration of a single thermochromic microcapsule is lower than 1wt%, the color saturation after mixing with the silicone rubber prepolymer is low, making it difficult to distinguish color changes. When the diameter of the thermochromic silicone rubber fiber is ≤0.5mm, the fiber transmittance increases, and the number of thermochromic microcapsules in the radial path of the fiber decreases, which will cause the color saturation of the fiber to decrease. The added concentration of the thermochromic microcapsules must be increased to achieve a thermochromic distinguishability close to that of thicker fibers. The required increased added concentration depends on the fiber diameter and the color and saturation of the thermochromic microcapsules. For example, in order to achieve similar color saturation, when the fiber diameter is 0.5mm, the added concentration of the thermochromic microcapsules needs to be increased by about 50%; when the fiber diameter is 0.3mm, the added concentration of the thermochromic microcapsules needs to be increased by about 100%; when the fiber diameter is 0.1mm, the added concentration of the thermochromic microcapsules needs to be increased by about 200%. When the concentration of a single thermosensitive color-changing microcapsule increases, the color saturation of the thermosensitive color-changing silicone rubber fiber imparted by the thermosensitive color-changing microcapsule will be enhanced, but this enhancement effect is no longer obvious when the concentration of the single thermosensitive color-changing microcapsule is higher than 5wt%. Further increasing the concentration of the single thermosensitive color-changing microcapsule will only increase the fiber cost.

[0021] As the concentration of thermochromic microcapsules increases, the microstructure and mechanical properties of the thermochromic silicone rubber fiber gradually decrease. A concentration of 15 wt% produces a significant negative impact. Therefore, the total concentration should be increased to 5 wt% to 15 wt% only when multiple thermochromic microcapsules are added.

[0022] In addition, different types of thermochromic microcapsules have different pre- and post-coloration colors and color change temperatures. When a single type of thermochromic microcapsule is mixed in, the pre- and post-coloration colors and color change temperature of the thermochromic silicone rubber fiber will be consistent with those of the single type of thermochromic microcapsule. Depending on the temperature change during the heating process, the thermochromic microcapsules can undergo three types of changes: color to colorless (abbreviated as "color to colorless"), color to color (from one color to another, abbreviated as "color to color"), and colorless to color (abbreviated as "colorless to color"). Therefore, when a single type of thermochromic microcapsule is mixed in, the three thermosensitive color change processes of "color to colorless," "color to color," and "colorless to color" can be achieved. When a single type of thermochromic microcapsule is mixed in, within the above-mentioned addition concentration range, thermochromic microcapsules of various colors can all cause the thermochromic silicone rubber fiber to produce a distinguishable thermochromic ability.

[0023] When incorporating multiple thermochromic microcapsules, these microcapsules must possess different color-changing temperatures and colors. The resulting thermochromic silicone rubber fiber will undergo multiple color changes within the color-changing temperature ranges of each thermochromic microcapsule. The color-changing temperature of a thermochromic microcapsule typically spans a temperature range, rather than a precise point. Therefore, the color-changing temperatures of the various thermochromic microcapsules must differ by more than 3°C to ensure that the color-changing temperatures of the different thermochromic microcapsules can be distinguished. The color of the thermochromic silicone rubber fiber in each color-changing temperature range is the sum of the colors of the various thermochromic microcapsules within that temperature range. As the number of thermochromic microcapsules incorporated increases, the color distinction between the fiber before and after color change decreases. This decrease is exacerbated when the hues of the various thermochromic microcapsules are similar. Therefore, when incorporating multiple thermochromic microcapsules, it is important to select microcapsules with hue h values that differ by more than 60°.

[0024] Thermochromic microcapsules are easier to distinguish when their hues are the three primary colors (RGB values: red 255-0-0, green 0-255-0, blue 0-0-255), or when they are black, which has a significant brightness difference from the transparent or translucent white silicone rubber. Therefore, when introducing two to three types of thermochromic microcapsules, the preferred type is one that has the three primary colors or black before or after the color change. When introducing four to five types of thermochromic microcapsules, after selecting the three primary colors or black, you can choose one that has purple (255-0-255) or cyan (0-255-255) before or after the color change. Yellow is closer to the transparent or translucent white color of silicone rubber itself, making it difficult to distinguish when multiple thermochromic microcapsules are mixed in. When mixing ≥3 types of thermochromic microcapsules, the yellow type should be excluded.

[0025] When mixing multiple thermochromic microcapsules, the three types of thermochromic microcapsules—"active to non-active," "active to active," and "non-active to active"—need to be appropriately matched to achieve a more distinguishable multi-stage thermochromic effect. First, the color change temperatures of the various thermochromic microcapsules are compared. The following description of the combinations of thermochromic microcapsules is arranged from low to high temperatures. When two thermochromic microcapsules are mixed, any two of the three types can be combined. As long as the hue difference between the two thermochromic microcapsules before and after the color change meets the above requirements, a distinguishable thermochromic effect can be produced. When three thermochromic microcapsules are mixed, the three possible combinations are "active to non-active" + "active to active" + "non-active to active," "active to non-active" + "active to non-active" + "non-active to active," and "active to non-active" + "non-active to active" + "non-active to active." The common rule is that the thermochromic microcapsules with the lowest color change temperature are not of the "non-active to active" type, and the thermochromic microcapsules with the highest color change temperature are not of the "active to non-active" type. When the number of mixed types is ≥4, avoid using the "with color change" type of thermochromic microcapsules. This is because the color before and after the color change affects the color of both the low-temperature side and the high-temperature side, making the controllability worse than the other two types of thermochromic microcapsules. When the number of mixed types is 4, you can choose the following combinations: "with color change without" + "with color change without" + "with color change without" + "without color change with" or "with color change without" + "with color change without" + "without color change with" + "without color change with" + "without color change with"; when the number of mixed types is 5, you can choose the following combinations: "with color change without" + "with color change without" + "with color change without" + "with color change without" + "without color change with" + "without color change with", or "with color change without" + "with color change without" + "without color change without" + "without color change with" + "without color change with" + "without color change with". The common rule when ≥4 types are mixed is that the thermosensitive color-changing microcapsules with lower color-changing temperatures are of the "with to none" type, the thermosensitive color-changing microcapsules with higher color-changing temperatures are of the "without to yes" type, and the number of "without to yes" type thermosensitive color-changing microcapsules is ≤2. The "with to none" type thermosensitive color-changing microcapsules with the lowest temperature are preferably the black to colorless type.

[0026] Preferably, the thermochromic microcapsules are added to the silicone rubber prepolymer for physical mixing, and the silicone rubber / thermochromic microcapsule mixed prepolymer is obtained after degassing.

[0027] Specifically, silicone rubber / thermochromic microcapsule mixed prepolymers with viscosities less than 10 Pa·s are degassed using vacuum extraction, while those with viscosities greater than 10 Pa·s are degassed using centrifugation. The centrifugal speed should be increased as the prepolymer viscosity increases, ensuring that bubbles are removed without the thermochromic microcapsules being centrifuged to the bottom. The color of the silicone rubber / thermochromic microcapsule mixed prepolymer does not change after being prepared into fibers. Therefore, the temperature-sensitive color-changing ability of the resulting thermochromic silicone rubber fiber can be pre-evaluated by observing the color changes of the silicone rubber / thermochromic microcapsule mixed prepolymer at different temperatures.

[0028] Preferably, in step (2), the hydrogel precursor solution comprises at least one of an aqueous alginate solution, an aqueous polyacrylic acid solution, and an aqueous polyvinyl alcohol solution. The hydrogel precursor solution is selected so as to be able to rapidly gel when extruded into a coagulation bath liquid to form hydrogel fibers.

[0029] Preferably, the alginate aqueous solution comprises a sodium alginate aqueous solution.

[0030] Preferably, in step (2), the coagulation bath solution comprises at least one of a calcium salt aqueous solution, an aluminum salt aqueous solution, and a borax aqueous solution.

[0031] Specifically, the coagulation bath solution of the alginate aqueous solution is a calcium salt aqueous solution, and the solute in the calcium salt aqueous solution includes at least one of calcium chloride and calcium nitrate; the coagulation bath solution of the polyacrylic acid aqueous solution is an aluminum salt aqueous solution, and the solute in the aluminum salt aqueous solution includes at least one of aluminum nitrate, aluminum sulfate and aluminum chloride; the coagulation bath solution of the polyvinyl alcohol aqueous solution is a borax aqueous solution.

[0032] Preferably, the mass concentration of the hydrogel precursor solution is 0.9-3.3%; further preferably, the mass concentration of the hydrogel precursor solution is 1-3%.

[0033] Preferably, the mass concentration of the coagulation bath solution is 0.9-5.5%; further preferably, the mass concentration of the coagulation bath solution is 1-5%.

[0034] Specifically, taking an alginate aqueous solution and a calcium chloride aqueous solution as examples, alginate is prepared as an aqueous solution with a concentration of 0.9 wt % to 3.3 wt %, and calcium chloride is prepared as an aqueous solution with a concentration of 0.9 wt % to 5.5 wt %.

[0035] Preferably, in step (2), the core-shell fiber is retained in a coagulation bath solution for cross-linking and curing to obtain a temperature-sensitive color-changing silicone rubber fiber, and the cross-linking temperature is determined by the type of silicone rubber; further preferably, the cross-linking and curing temperature is 25-150°C.

[0036] Preferably, in step (2), the coaxial spinning device includes an inner spinning head and an outer spinning head arranged coaxially, and the inner spinning head and the outer spinning head form an annular channel; the inner spinning head is connected to a first pushing device for extruding the silicone rubber / thermosensitive color-changing microcapsule mixed prepolymer through the inner spinning head; the outer spinning head is connected to a second pushing device for extruding the hydrogel precursor solution through the annular channel.

[0037] Specifically, the inner spinning head and the outer spinning head are both hollow cylindrical structures, the inner diameter of the outer spinning head is larger than the outer diameter of the inner spinning head, and the inner spinning head and the outer spinning head form an annular channel.

[0038] Preferably, the inner diameter of the inner spinning head is 160 μm to 2000 μm. After the thermochromic microcapsules are introduced, micron-sized solid particles are present in the silicone rubber / thermochromic microcapsule mixed prepolymer. This results in excessive extrusion resistance for silicone rubber / thermochromic microcapsule mixed prepolymer when the inner spinning head inner diameter is less than 160 μm. For inner spinning heads with an inner diameter greater than 2000 μm, the resulting thermochromic silicone rubber fiber is too thick, affecting the fiber's thermochromic response speed.

[0039] Preferably, the tube wall thickness of the inner spinning head is 50 μm-1000 μm, which varies in a positive correlation with the inner diameter of the inner spinning head.

[0040] Preferably, an annular channel is formed between the inner and outer spinning heads, and the spacing between the outer and inner walls of the annular channel is 80 μm to 2000 μm, varying in direct correlation with the inner diameter of the inner spinning head and need to be between 0.5 and 1 times the inner diameter of the inner spinning head. Based on the above structure and dimensions, a coaxial needle prepared from a needle or a custom-made and processed coaxial spinning head can be used.

[0041] Specifically, by adjusting the diameters of the inner spinning head and the outer spinning head, the diameter of the silicone rubber / thermochromic microcapsule mixed prepolymer core and the thickness of the hydrogel shell can be adjusted.

[0042] Specifically, depending on the viscosity of the silicone rubber / thermochromic microcapsule mixed prepolymer, the fiber diameter of the thermochromic silicone rubber fiber is affected by the inner diameter of the inner spinning head and the inner diameter of the outer spinning head. When the viscosity of the silicone rubber / thermochromic microcapsule mixed prepolymer is low (for example, a liquid with a viscosity of less than 10 Pa·s), the diameter of the thermochromic silicone rubber fiber is affected by the inner diameter of the outer spinning head, and the fiber diameter is between a and b times the inner diameter of the outer spinning head, typically a = 0.8 and b = 1.2. When the viscosity of the silicone rubber / thermochromic microcapsule mixed prepolymer is high (for example, a semi-solid with a viscosity of more than 200 Pa·s), the diameter of the thermochromic silicone rubber fiber is affected by the inner diameter of the inner spinning head, and the fiber diameter is between c and d times the inner diameter of the inner spinning head, typically c = 0.5 and d = 2.

[0043] As the viscosity of the silicone rubber / thermochromic microcapsule prepolymer mixture increases, the a, b, c, and d values all decrease, meaning the diameter of the thermochromic silicone rubber fiber decreases. The difference between the a and b values increases because increased viscosity improves the spinnability of the lower-viscosity prepolymer, while the difference between the c and d values decreases because increased viscosity reduces the cross-sectional deformation capacity of the higher-viscosity prepolymer. Because the inner diameter of the outer spinning head is necessarily larger than that of the inner spinning head, the diameter of the thermochromic silicone rubber fiber is negatively correlated with the viscosity of the silicone rubber / thermochromic microcapsule prepolymer mixture, exhibiting a quantitative change with viscosity. Adding thermochromic microcapsules to the silicone rubber prepolymer increases the prepolymer viscosity, which is positively correlated with the added concentration of the thermochromic microcapsules. The lower the viscosity of the silicone rubber prepolymer, the more pronounced the change in fiber diameter caused by the viscosity change caused by the addition of thermochromic microcapsules.

[0044] Preferably, in step (2), the extrusion flow rate ratio of the silicone rubber / thermochromic microcapsule mixed prepolymer and the hydrogel precursor solution is (0.05-2):1.

[0045] Specifically, the diameter of the thermochromic silicone rubber fiber is adjusted by the extrusion flow rate of the silicone rubber / thermochromic microcapsule mixed prepolymer and the hydrogel precursor solution, that is, by the flow rate ratio of the first pushing device and the second pushing device. The extrusion flow rate ratio needs to be set according to the viscosity of the silicone rubber / thermochromic microcapsule mixed prepolymer. When the viscosity of the silicone rubber / thermochromic microcapsule mixed prepolymer is low (for example, a liquid with a viscosity of less than 10Pa·s), when the extrusion flow rate ratio is between 0.5 and 2, a continuous thermochromic silicone rubber fiber will be prepared, and the diameter of the thermochromic silicone rubber fiber is positively correlated with the extrusion flow rate ratio, and varies within the diameter controllable range between the above-mentioned a value and b value. When the viscosity of the silicone rubber / thermochromic microcapsule mixed prepolymer is high (for example, a semi-solid with a viscosity greater than 200 Pa·s), continuous thermochromic silicone rubber fibers can be prepared within the range of this flow rate ratio of 0.05-2, and the fiber diameter is positively correlated with the extrusion flow rate ratio, varying within the diameter controllable range between the above-mentioned c value and d value. However, when this value is increased by increasing the extrusion flow rate of the silicone rubber / thermochromic microcapsule mixed prepolymer, the resistance during extrusion will increase, which may cause a pressure overload in the extrusion system. Therefore, it is necessary to set the extrusion flow rate of the silicone rubber / thermochromic microcapsule mixed prepolymer that can be stably extruded according to the viscosity of the silicone rubber / thermochromic microcapsule mixed prepolymer and the diameter of the spinning head.

[0046] Based on this, by observing the diameter of the extruded core fiber, adjusting the extrusion flow rate of the hydrogel precursor solution, and further adjusting the flow rate ratio of the two fluids, the diameter of the thermochromic silicone rubber fiber can be finely controlled. Alternatively, adjusting the temperature of the coagulation bath solution to achieve a color that is easily distinguishable from the hydrogel facilitates observation of the core fiber morphology and diameter.

[0047] Preferably, in step (2), the core-shell fiber is placed in the coagulation bath solution to solidify the core of the core-shell fiber, and then the shell of the core-shell fiber is removed to obtain a linear temperature-sensitive color-changing silicone rubber fiber;

[0048] Alternatively, the core-shell fiber is wound on a substrate to obtain a spiral core-shell fiber; then the whole is placed in the coagulation bath solution to solidify the core of the spiral core-shell fiber, and removed from the substrate, and then the outer shell of the spiral core-shell fiber is removed to obtain a spiral temperature-sensitive color-changing silicone rubber fiber.

[0049] Specifically, when preparing the linear temperature-sensitive color-changing silicone rubber fiber, after placing the core-shell fiber in the coagulation bath solution, avoid moving the core-shell fiber.

[0050] Specifically, when preparing the spiral thermochromic silicone rubber fiber, the newly prepared core-shell fiber is wound on the substrate, so that the silicone rubber / thermochromic microcapsule core fiber that has not yet been cross-linked is shaped into a spiral.

[0051] Preferably, when preparing the spiral temperature-sensitive color-changing silicone rubber fiber, the matrix includes a rod-shaped object or a tube-shaped object; further preferably, the matrix includes a cylindrical rod-shaped object or a cylindrical tube-shaped object.

[0052] Specifically, when preparing spiral thermochromic silicone rubber fibers, the selection criteria for silicone rubber, in addition to the above-mentioned performance requirements, must additionally meet the following requirements: the viscosity of the silicone rubber prepolymer is 100 to 1000 Pa·s. A higher viscosity of the silicone rubber prepolymer is conducive to maintaining a uniform spiral structure during winding and shaping; the Shore hardness after cross-linking is 20 to 70. A higher Shore hardness is conducive to the spiral thermochromic silicone rubber fiber maintaining its spiral structure.

[0053] When preparing core-shell fibers, a higher extrusion flow rate ratio of the silicone rubber / thermochromic microcapsule prepolymer to the hydrogel precursor solution reduces the thickness of the hydrogel shell, which helps reduce the coil spacing and improve the uniformity of the helical structure. Therefore, this extrusion flow rate ratio is set between 1.0 and 2.0. By controlling the diameter of the silicone rubber / thermochromic microcapsule prepolymer core, the diameter of the resulting helical thermochromic silicone rubber fiber can be adjusted.

[0054] Preferably, before the core-shell fiber is wound around the substrate, the core-shell fiber is immersed in a coagulation bath liquid for 10 to 20 minutes, so that the hardness of the hydrogel shell is further increased and the thickness is reduced, which is conducive to the stability of the winding process, and can further reduce the coil spacing and improve the uniformity of the spiral structure.

[0055] Specifically, the winding process is as follows: the upper end of the core-shell fiber is raised from the surface of the coagulation bath, fixed to one end of the cylindrical substrate with a small clip or a tie wire, the cylindrical substrate is kept horizontally, the axis of the cylindrical substrate is at a height H from the liquid surface, and the core-shell fiber is wound onto the cylindrical substrate manually or by a motor; during the winding process, the part of the core-shell fiber raised from the water surface is kept in a vertical direction, the core-shell fiber will spontaneously wind around the cylindrical substrate to form a close spiral coil until the entire core-shell fiber is wound, or the cylindrical substrate is fully wrapped with a layer of spiral fiber, and the end is fixed with a small clip or a tie wire.

[0056] The diameter of the helical structure can be controlled by adjusting the diameter of the cylindrical substrate, which is 0.5 to 3 times the diameter of the core-shell fiber. An overly thin cylindrical substrate requires excessively high winding tension, resulting in a flat cross-section of the helical thermochromic silicone rubber fiber. An overly thick cylindrical substrate results in excessively large helical curvature, hindering the fiber's ability to maintain its helical structure. By controlling the H value between 10 cm and 100 cm, the winding tension is adjusted to adjust the degree of flattening of the resulting helical thermochromic silicone rubber fiber.

[0057] The H value has a lower limit for achieving stable spiral winding, and this lower limit is positively correlated with the ratio of the core-shell fiber diameter to the cylindrical matrix diameter. That is, the thicker the core-shell fiber and the thinner the cylindrical matrix, the higher the lower limit of the H value is required to achieve stable winding. At this lower limit of the H value, a spiral thermochromic silicone rubber fiber cross-section closest to a circle can be achieved. On this basis, further increasing the H value will cause the cross-section of the spiral thermochromic silicone rubber fiber to become flatter. The flattening of the cross-section of the spiral thermochromic silicone rubber fiber will increase the degree of stress unevenness when stretched under tension, which is not conducive to the fiber's elongation and breaking strength. However, the reduction in the short axis diameter of the cross-section is conducive to the conduction of heat from the inside of the spiral to the outside of the spiral, which is beneficial to the thermochromic ability. Therefore, it needs to be regulated on demand according to application requirements.

[0058] Preferably, the process of removing the shell of the core-shell fiber is to place the cured core-shell fiber in a shell removal solution for immersion; the shell removal solution includes at least one of a sodium citrate aqueous solution, an ethylenediaminetetraacetic acid aqueous solution, and a hydrochloric acid aqueous solution, and the shell removal solution can dissolve and remove the hydrogel shell.

[0059] Preferably, after removing the hydrogel shell, the method further includes washing and drying the linear or spiral temperature-sensitive color-changing silicone rubber fibers.

[0060] Preferably, the temperature-sensitive color-changing silicone rubber fiber can be soaked in alkali solution to reduce the degree of reflection on the surface of the temperature-sensitive color-changing silicone rubber fiber, thereby improving the color consistency when observed at different angles.

[0061] The temperature-sensitive color-changing silicone rubber fiber of the present invention has excellent corrosion resistance and shows excellent corrosion resistance to neutral salt solutions, acid solutions, detergents and other solutions. It can only be treated for surface corrosion by alkali solution. The temperature-sensitive color-changing silicone rubber fiber is placed in a sodium hydroxide solution or other alkaline solution and soaked for 1 to 20 days. Increasing the concentration of the alkali solution or the temperature can shorten the soaking time. Through naked eye observation, the reflectivity of the surface of the temperature-sensitive color-changing silicone rubber fiber disappears and the fiber diameter does not decrease significantly. After soaking in alkali solution, pits with a size of hundreds of nanometers to 5 microns will appear on the surface of the temperature-sensitive color-changing silicone rubber fiber, which can diffusely reflect light, thereby improving the color consistency of the fiber when observed at different angles. However, surface alkali solution treatment will reduce the anti-fouling and mechanical properties of the temperature-sensitive color-changing silicone rubber fiber to a certain extent, and this step needs to be performed selectively according to application requirements.

[0062] A second aspect of the present invention provides a temperature-sensitive color-changing silicone rubber fiber.

[0063] Specifically, the temperature-sensitive color-changing silicone rubber fiber is prepared by the preparation method of the temperature-sensitive color-changing silicone rubber fiber described in the first aspect of the present invention.

[0064] A third aspect of the present invention provides a fabric or a component having a temperature sensing function.

[0065] Specifically, the raw materials for preparing the fabric or the component with temperature sensing function include the temperature-sensitive color-changing silicone rubber fiber described in the second aspect of the present invention.

[0066] Preferably, the method for using the temperature-sensitive color-changing silicone rubber fiber comprises the following steps:

[0067] When the thermochromic silicone rubber fiber is a single linear thermochromic silicone rubber fiber, it is used as a single fiber independently, or the single fiber is sewn into a fabric or the single fiber is woven into a fabric;

[0068] When the thermochromic silicone rubber fibers are multiple linear thermochromic silicone rubber fibers, the fibers are arranged in rows, sewn into fabric, or woven into fabric.

[0069] When the temperature-sensitive color-changing silicone rubber fiber is a spiral temperature-sensitive color-changing silicone rubber fiber, it is used by being wound on a substrate in a single or multiple parallel manner.

[0070] Specifically, by simultaneously using multiple linear thermochromic silicone rubber fibers added with one or more thermochromic microcapsules, more color-changing temperature segments can be achieved through combination and arrangement, requiring that the color-changing temperature points of the multiple thermochromic silicone rubber fibers have a difference of at least 2°C.

[0071] Based on the above-mentioned simultaneous use of multiple thermochromic silicone rubber fibers, further structural design can be carried out to achieve more diverse thermochromic effects. For example, after multiple linear thermochromic microcapsules are arranged in rows, they are bonded with a silicone rubber prepolymer of the same component as the fibers. After the silicone rubber prepolymer is cross-linked, a thermochromic silicone rubber fiber array is prepared, which can be cut into pieces of 0.5 cm to 10 cm as needed to obtain thermochromic silicone rubber fiber array sheets of different lengths. For example, soft and elastic thermochromic silicone rubber fibers have excellent weavability. Single or multiple linear thermochromic silicone rubber fibers can be sewn into fabrics to obtain patterns that can change color. In order to achieve color distinguishability when multiple thermochromic silicone rubber fibers are used simultaneously, each fiber needs to have a different color change sequence from low temperature to high temperature.

[0072] In another approach, multiple linear thermochromic silicone rubber fibers with different color-changing temperatures but the same color change sequence from low to high temperatures are sewn into or woven into a fabric to create an information-encrypted fabric that displays patterns within specific temperature ranges. For example, two thermochromic silicone rubber fibers with the same color before and after color change but different color-changing temperatures are used. One fiber is sewn with an "A" pattern, while the other is sewn with a background area. When the temperature is below the color-changing temperatures of the two fibers, the sewn area has no pattern. When the temperature is between the two fiber color-changing temperatures, the sewn area displays the "A" pattern. When the temperature is above the two fiber color-changing temperatures, the "A" pattern disappears. By increasing the number of fibers and the color-changing temperature range of each fiber, more complex information encryption effects can be achieved.

[0073] Specifically, the spiral temperature-sensitive color-changing silicone rubber fiber can be autonomously wrapped around a variety of rod-shaped or tubular objects without being fixed, including but not limited to wires, plant stems, fingers, animal tails, poultry tarsometatarsals, infusion tubes, microfluidic pipes, etc., and can perform visual temperature detection on temperature changes caused by the rod-shaped or tubular objects themselves or the external environment.

[0074] The spiral inner diameter of the thermochromic silicone rubber fiber is 0.8 to 1 times the diameter of the cylindrical substrate, achieving a relatively tight, self-winding effect. By using multiple spiral thermochromic silicone rubber fibers with one or more thermochromic microcapsules, they can be wound side by side on the cylindrical substrate to achieve a wider range of color change temperature segments. The color change points of the multiple thermochromic silicone rubber fibers must differ by at least 2°C.

[0075] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0076] (1) The present invention uses coaxial spinning technology to obtain core-shell fibers with a silicone rubber / thermochromic microcapsule mixed prepolymer as the core and a hydrogel as the shell. The hydrogel provides shaping and protection for the core during the curing process of the core, and then the shell is removed to obtain a thermochromic silicone rubber fiber. Since the thermochromic microcapsules are present in the fiber and are not easily detached, the fiber has a stable thermochromic ability. The thermochromic silicone rubber fiber has good elastic mechanical properties, heat resistance, solvent resistance, corrosion resistance, a visible and diverse thermochromic ability, and a linear or spiral fiber structure, which makes it suitable for applications in temperature sensors, fashion fabrics, biomedicine and other fields.

[0077] (2) The thermochromic silicone rubber fiber of the present invention has the characteristic of bright colors. When the temperature changes across the color change temperature of the thermochromic microcapsules, obvious color changes will occur. By selecting the color and color change temperature of the thermochromic microcapsules, controlling the added concentration of a single thermochromic microcapsule, adding multiple types of thermochromic microcapsules and adjusting the matching method, a variety of thermochromic functions can be achieved.

[0078] Linear temperature-sensitive color-changing silicone rubber fibers can be used in a variety of ways, including as single fibers, in rows of multiple fibers, sewn into fabrics, or woven into fabrics, to achieve functions such as temperature sensing, color-changing fabrics, and pattern display. Single or multiple spiral temperature-sensitive color-changing silicone rubber fibers can be wrapped around rods or tubes, realizing temperature sensing when the temperature of the liquid in the rods or tubes changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 Schematic diagram of the preparation process and temperature-sensitive color change process of the linear temperature-sensitive color-changing silicone rubber fiber and the spiral temperature-sensitive color-changing silicone rubber fiber of the present invention;

[0080] Figure 2 2. The actual image of the linear temperature-sensitive color-changing silicone rubber fiber prepared in Example 1 of the present invention before and after heating;

[0081] Figure 3 This is a physical picture of the spiral temperature-sensitive color-changing silicone rubber fibers with different structures prepared in Example 1 of the present invention;

[0082] Figure 4 This is a graph showing the mechanical properties test results of the linear temperature-sensitive color-changing silicone rubber fiber prepared in Example 1 of the present invention;

[0083] Figure 5 This is a graph showing the heat resistance test results of the linear temperature-sensitive color-changing silicone rubber fiber prepared in Example 1 of the present invention;

[0084] Figure 6 This is a graph showing the corrosion resistance test results of the linear temperature-sensitive color-changing silicone rubber fiber prepared in Example 1 of the present invention;

[0085] Figure 7 This is a photo of four temperature-sensitive color-changing silicone rubber fibers with multi-stage color-changing capabilities produced in Example 2 of the present invention;

[0086] Figure 8 This is a photo of the use of the spiral temperature-sensitive color-changing silicone rubber fiber prepared in Example 3 of the present invention wound around a steel rod;

[0087] Figure 9 This is a photo of the use of the spiral temperature-sensitive color-changing silicone rubber fiber prepared in Example 3 of the present invention being wound around an infusion tube. DETAILED DESCRIPTION

[0088] In order to make the technical solution of the present invention more clearly understood by those skilled in the art, the following examples are given for illustration. It should be noted that the following examples do not limit the scope of protection claimed by the present invention.

[0089] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0090] The preparation process of the linear temperature-sensitive color-changing silicone rubber fiber and the spiral temperature-sensitive color-changing silicone rubber fiber of the present invention and the schematic diagram of the temperature-sensitive color-changing process are shown in FIG. Figure 1 shown.

[0091] Example 1

[0092] A method for preparing temperature-sensitive color-changing silicone rubber fiber comprises the following steps:

[0093] (1) Silicone rubber prepolymer (Dow Corning, SE1700) and thermochromic microcapsules (Shenzhen Huancai, purple to blue at 31 degrees) were physically stirred and mixed. The concentrations of the thermochromic microcapsules added were 0 (control), 0.5 wt%, 1 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%, and 15 wt%, respectively. The mixture was centrifuged to remove air bubbles, and 9 groups of silicone rubber / thermochromic microcapsule mixed prepolymers were obtained.

[0094] (2) preparing a coaxial spinning apparatus with inner and outer spinning heads of 22G (inner diameter 0.4 mm, outer diameter 0.7 mm) and 16G (inner diameter 1.15 mm, outer diameter 1.6 mm), 16G (inner diameter 1.15 mm, outer diameter 1.6 mm) and 12G (inner diameter 2.3 mm, outer diameter 2.8 mm), and 12G (inner diameter 2.3 mm, outer diameter 2.8 mm) and 8G (inner diameter 3.5 mm, outer diameter 4.0 mm), respectively;

[0095] A sodium alginate aqueous solution with a mass concentration of 1.5 wt% was connected to the outer spinning head of a coaxial spinning apparatus, and nine groups of silicone rubber / thermochromic microcapsule mixed prepolymers were connected to the inner spinning head of the coaxial spinning apparatus. Through the coaxial spinning apparatus, the silicone rubber / thermochromic microcapsule mixed prepolymer and the sodium alginate aqueous solution were co-extruded into a calcium chloride aqueous solution at a flow rate ratio of 1:1 to obtain core-shell fibers with an inner core of the silicone rubber / thermochromic microcapsule mixed prepolymer and an outer shell of the alginate hydrogel.

[0096] For linear thermochromic silicone rubber fibers, a 16G (inner diameter 1.15 mm, outer diameter 1.6 mm)-12G (inner diameter 2.3 mm, outer diameter 2.8 mm) coaxial needle was used for preparation; the core-shell fibers obtained in step (2) were retained in a calcium chloride aqueous solution, heated at 80° C. for cross-linking and curing to solidify the silicone rubber / thermochromic microcapsule mixed prepolymer core, and then the core-shell fibers were immersed in a sodium citrate aqueous solution to dissolve and remove the hydrogel shell, and then washed and dried to obtain linear thermochromic silicone rubber fibers with different thermochromic microcapsule concentrations;

[0097] For the spiral thermochromic silicone rubber fiber, the thermochromic silicone rubber fiber was prepared by 22G (inner diameter 0.4mm, outer diameter 0.7mm)-16G (inner diameter 1.15mm, outer diameter 1.6mm), 16G (inner diameter 1.15mm, outer diameter 1.6mm)-12G (inner diameter 2.3mm, outer diameter 2.8mm) and 12G (inner diameter 2.3mm, outer diameter 2.8mm)-8G (inner diameter 3.5mm, outer diameter 4.0mm) coaxial needles. The added concentration of microcapsules is 5wt%, and the core-shell fibers are wrapped around steel rods with diameters of 1mm, 2mm, and 3mm to form spiral core-shell fibers. The fibers are then heated at 80°C for cross-linking and curing to solidify the inner core of the silicone rubber / thermochromic microcapsule mixed prepolymer. The spiral core-shell fibers are removed from the cylindrical steel rods and immersed in a sodium citrate aqueous solution to dissolve and remove the hydrogel shell. The fibers are then washed and dried to obtain spiral thermochromic silicone rubber fibers with different structures.

[0098] The actual pictures of the linear temperature-sensitive color-changing silicone rubber fiber prepared in Example 1 of the present invention before and after heating are as follows: Figure 2 As shown. Figure 2It can be seen that with the increase of the added concentration of thermochromic microcapsules, the color saturation of the thermochromic silicone rubber fiber before and after color change is enhanced, but this enhancement effect is no longer obvious when the concentration of a single thermochromic microcapsule is higher than 5wt%.

[0099] The actual pictures of the spiral temperature-sensitive color-changing silicone rubber fibers with different structures prepared in Example 1 of the present invention are as follows: Figure 3 As shown. Figure 3 It can be seen that the thermochromic silicone rubber fiber will maintain a spiral structure after being shaped on steel rods of different diameters and then heated, cross-linked and cured, and the spiral diameter of the spiral structure is regulated by the diameter of the steel rod, thereby obtaining spiral thermochromic silicone rubber fibers with different structures.

[0100] The mechanical properties of the linear temperature-sensitive color-changing silicone rubber fiber of Example 1 were tested. The specific testing method was as follows: using a 50N sensor and a movement speed of 100mm / min, a tensile test was performed on each group of fibers with a gauge length of 10mm, and the stress-strain curve was recorded during the stretching process until fracture. The curve was analyzed to obtain the Young's modulus, breaking strength, and elongation at break.

[0101] Example 1 The mechanical properties test results of the linear temperature-sensitive color-changing silicone rubber fiber are as follows: Figure 4 As shown. Figure 4 It can be seen that with the increase of the added concentration of thermosensitive color-changing microcapsules, the breaking elongation and breaking strength of the linear thermosensitive color-changing silicone rubber fiber gradually decrease.

[0102] The heat resistance of the linear temperature-sensitive color-changing silicone rubber fiber of Example 1 was tested. The specific testing method was as follows: the linear temperature-sensitive color-changing silicone rubber fiber with an additive concentration of 2 wt% prepared in Example 1 was placed in a room temperature of 25°C and an environment of 80-280°C (interval of 20°C) for heat treatment for 30 minutes, and then the fiber was cooled to room temperature, the appearance of the fiber was observed, and the mechanical properties of the fiber were tested.

[0103] Example 1 The heat resistance test results of the linear temperature-sensitive color-changing silicone rubber fiber are as follows: Figure 5 As shown. Among them, Figure 5 Figure (a) shows the actual picture of the linear temperature-sensitive color-changing silicone rubber fiber before and after color change after heat treatment. Figure 5 Figure (b) shows the mechanical properties test results of the linear thermochromic silicone rubber fiber after heat treatment.

[0104] Depend on Figure 5 As can be seen from Figure (a), with the increase of heat treatment temperature, the color of the fiber before discoloration gradually changes from purple to green-brown, and the color of the fiber after discoloration gradually changes from blue to green-brown. This color change is accompanied by the disappearance of the color changing ability, which occurs after 200℃. Figure 5As can be seen from Figure (b), with the increase of heat treatment temperature, the Young's modulus of the linear thermochromic silicone rubber fiber increases, the breaking strength first increases and then decreases, while the elongation at break decreases. After treatment at 200°C, it can still maintain excellent elastic mechanical properties.

[0105] The corrosion resistance of the linear temperature-sensitive color-changing silicone rubber fiber prepared in Example 1 was tested. The specific test method was as follows: the temperature-sensitive color-changing silicone rubber fiber with an addition concentration of 2 wt% prepared in Example 1 was immersed in 0.1 mol / L hydrochloric acid, 5 wt% sodium hydroxide, water, 5 wt% sodium chloride, and 5 wt% detergent solution for 100 days, and then the fiber was washed and dried, and the morphology and color change effect of the fiber before and after color change were observed.

[0106] The corrosion resistance test results of the linear temperature-sensitive color-changing silicone rubber fiber prepared in Example 1 are as follows: Figure 6 As shown. Among them, Figure 6 Figure (a) shows the corrosion resistance test results of the linear temperature-sensitive color-changing silicone rubber fiber in Example 1 after being immersed in different solutions. Figure 6 Figure (b) is a real-life picture of the diffuse reflection sample of the linear temperature-sensitive color-changing silicone rubber fiber in Example 1 before and after alkali solution treatment, and the left-side fibers in the left 45° lighting, top lighting, and right 45° lighting are all fibers that have not been treated with alkali solution, and the right-side fibers are all fibers that have been treated with alkali solution.

[0107] Depend on Figure 6 It can be seen that after long-term immersion in several solutions, the color of the thermochromic silicone rubber fiber did not change significantly before and after the color change. The linear thermochromic silicone rubber fiber that was not treated with alkali solution had a reflective surface, and the consistency of the fiber's color when viewed from different angles was easily affected by light. After alkali treatment, the reflective surface of the fiber disappeared, and the fiber's color remained consistent when viewed from different angles.

[0108] Example 2

[0109] A method for preparing temperature-sensitive color-changing silicone rubber fiber comprises the following steps:

[0110] (1) Prepare 4 parts of silicone rubber prepolymer (Dow Corning, SE1700) and 12 kinds of thermochromic microcapsules with different color-changing temperatures. Each part of silicone rubber prepolymer is mixed with 3 kinds of thermochromic microcapsules. Take one of the fibers as an example, add 3 kinds of thermochromic microcapsules (Shenzhen Huancai, black to colorless at 18℃, red to colorless at 28℃, colorless to blue at 35℃), and the addition concentration of each thermochromic microcapsule is 3wt%. Mix by physical stirring and remove bubbles by centrifugation to obtain silicone rubber / thermochromic microcapsule mixed prepolymer. The microcapsule combinations of the other three fibers are as follows: Shenzhen Huancai, red to colorless at 38℃, green to colorless at 50℃, colorless to rose red at 60℃; Shenzhen Huancai, black to colorless at 22℃, cyan to colorless at 33℃, colorless to orange at 40℃; Shenzhen Huancai, dark blue to colorless at 25℃, orange to colorless at 31℃, colorless to green at 40℃.

[0111] (2) preparing a coaxial spinning device with an inner spinning head of 16G (inner diameter 1.15 mm, outer diameter 1.6 mm) and an outer spinning head of 12G (inner diameter 2.3 mm, outer diameter 2.8 mm), respectively; connecting a sodium alginate aqueous solution with a mass concentration of 1.5 wt% to the outer spinning head of the coaxial spinning device, and connecting a silicone rubber / thermochromic microcapsule mixed prepolymer to the inner spinning head of the coaxial spinning device; and co-extruding the silicone rubber / thermochromic microcapsule mixed prepolymer and the sodium alginate aqueous solution into a calcium chloride aqueous solution through the coaxial spinning device at a flow rate ratio of 1:1.2 to obtain a core-shell fiber with an inner core of the silicone rubber / thermochromic microcapsule mixed prepolymer and an outer shell of the alginate hydrogel;

[0112] The core-shell fibers were retained in a calcium chloride aqueous solution and heated at 80°C for cross-linking and curing to solidify the inner core of the silicone rubber / thermochromic microcapsule mixed prepolymer. The core-shell fibers were then immersed in a sodium citrate aqueous solution to dissolve and remove the hydrogel shell. The fibers were then washed and dried to obtain four linear thermochromic silicone rubber fibers with different segmented thermochromic abilities.

[0113] The actual pictures of the four temperature-sensitive color-changing silicone rubber fibers with multi-stage color-changing capabilities prepared in Example 2 are as follows: Figure 7 As shown. Figure 7 It can be seen that due to the thermosensitive color-changing microcapsules added to each thermosensitive color-changing silicone rubber fiber, it has different color-changing effects under different temperature conditions, realizing diversified temperature-sensitive color-changing functions.

[0114] Example 3

[0115] A method for preparing temperature-sensitive color-changing silicone rubber fiber comprises the following steps:

[0116] (1) Prepare 4 parts of silicone rubber prepolymer (Dow Corning, SE1700) and 12 kinds of thermochromic microcapsules with different color-changing temperatures. Each part of silicone rubber prepolymer is mixed with 3 kinds of thermochromic microcapsules. Taking one of the fibers as an example, 3 kinds of thermochromic microcapsules (Shenzhen Huancai, black to colorless at 18℃, red to colorless at 28℃, colorless to blue at 35℃) are added to each part of silicone rubber prepolymer. The concentration of each thermochromic microcapsule is 3wt%. The mixture is mixed by physical stirring and centrifuged to remove bubbles to obtain a silicone rubber / thermochromic microcapsule mixed prepolymer. The microcapsule combinations of the other three fibers are as follows: Shenzhen Huancai, red to colorless at 38℃, green to colorless at 50℃, colorless to rose red at 60℃; Shenzhen Huancai, black to colorless at 22℃, cyan to colorless at 33℃, colorless to orange at 40℃; Shenzhen Huancai, dark blue to colorless at 25℃, orange to colorless at 31℃, colorless to green at 40℃.

[0117] (2) preparing a coaxial spinning device with an inner spinning head of 16G (inner diameter 1.15 mm, outer diameter 1.6 mm) and an outer spinning head of 12G (inner diameter 2.3 mm, outer diameter 2.8 mm), respectively; connecting a sodium alginate aqueous solution with a mass concentration of 1.5 wt% to the outer spinning head of the coaxial spinning device, and connecting a silicone rubber / thermochromic microcapsule mixed prepolymer to the inner spinning head of the coaxial spinning device; and co-extruding the silicone rubber / thermochromic microcapsule mixed prepolymer and the sodium alginate aqueous solution into a calcium chloride aqueous solution at a flow rate ratio of 1:0.8 through the coaxial spinning device to prepare a core-shell fiber with an inner core of the silicone rubber / thermochromic microcapsule mixed prepolymer and an outer shell of the alginate hydrogel;

[0118] The core-shell fibers were wrapped around a 2mm diameter steel rod and then placed in a calcium chloride aqueous solution. They were heated at 80°C for cross-linking and curing to solidify the silicone rubber / thermochromic microcapsule mixed prepolymer core. The spiral core-shell fibers were removed from the cylindrical steel rod and immersed in a sodium citrate aqueous solution to dissolve and remove the hydrogel shell. The fibers were then washed and dried to prepare four spiral thermochromic silicone rubber fibers with different segmented thermochromic abilities.

[0119] Four spiral temperature-sensitive color-changing silicone rubber fibers are wound around a steel rod or an infusion tube, and the steel rod is heated, or hot water is passed through the infusion tube to achieve the temperature sensing function.

[0120] The actual process of using the spiral temperature-sensitive color-changing silicone rubber fiber wound around the steel rod prepared in Example 3 of the present invention is shown in the figure below: Figure 8 As shown. Among them, Figure 8 Figure (a) shows a real picture of a spiral temperature-sensitive color-changing silicone rubber fiber wrapped around a steel rod. Figure 8 Figure (b) shows the color state of the spiral thermochromic silicone rubber fiber when the right side of the steel rod is initially heated; Figure 8Figure (c) shows the color state of the spiral temperature-sensitive color-changing silicone rubber fiber when heat is transferred to the left during the heating process.

[0121] The actual process of using the spiral temperature-sensitive color-changing silicone rubber fiber prepared in Example 3 of the present invention wound around the infusion tube is shown in the figure below: Figure 9 shown. Figure 9 Figure (a) shows a real-life picture of a spiral temperature-sensitive color-changing silicone rubber fiber wrapped around an infusion tube. Figure 9 Figure (b) shows the color state of the spiral temperature-sensitive color-changing silicone rubber fiber when hot water is just added to the infusion tube; Figure 9 Figure (c) shows the color state of the spiral temperature-sensitive color-changing silicone rubber fiber after hot water is passed into the infusion tube.

[0122] Depend on Figure 8 、 9 It can be seen that when the steel rod is heated or hot water is passed into the infusion tube, the spiral temperature-sensitive color-changing silicone rubber fiber will change color, which can be used to visually detect the temperature change and realize the temperature sensing function.

[0123] Example 4

[0124] A method for preparing temperature-sensitive color-changing silicone rubber fiber comprises the following steps:

[0125] (1) Preparing a silicone rubber prepolymer (Smooth-On, Ecoflex 00-30) and thermochromic microcapsules (Shenzhen Dongfang Bianse, product model: DF-06-10, 28-33°C), wherein the concentration of the thermochromic microcapsules is 10 wt%, and mixing by physical stirring and vacuuming to remove bubbles to obtain a silicone rubber / thermochromic microcapsule mixed prepolymer;

[0126] (2) preparing a coaxial spinning device with an inner spinning head of 24G (inner diameter 0.27 mm, outer diameter 0.55 mm) and an outer spinning head of 18G (inner diameter 0.86 mm, outer diameter 1.26 mm), respectively; connecting a sodium alginate aqueous solution with a mass concentration of 3 wt% to the outer spinning head of the coaxial spinning device, and connecting a silicone rubber / thermochromic microcapsule mixed prepolymer to the inner spinning head of the coaxial spinning device; and co-extruding the silicone rubber / thermochromic microcapsule mixed prepolymer and the sodium alginate aqueous solution into a calcium chloride aqueous solution at a flow rate ratio of 1:2 through the coaxial spinning device to prepare a core-shell fiber with an inner core of the silicone rubber / thermochromic microcapsule mixed prepolymer and an outer shell of the alginate hydrogel;

[0127] The core-shell fiber is retained in a calcium chloride aqueous solution and cross-linked and cured at room temperature to solidify the inner core of the silicone rubber / thermochromic microcapsule mixed prepolymer. The core-shell fiber is then immersed in a sodium citrate aqueous solution to dissolve and remove the hydrogel shell, and then washed and dried to prepare a three-stage color-changing thermosensitive color-changing silicone rubber fiber at temperatures below 28°C, 28°C to 33°C, and above 33°C.

[0128] In summary, the present invention utilizes coaxial spinning technology to produce core-shell fibers composed of a silicone rubber / thermochromic microcapsule mixed prepolymer core and a hydrogel shell. The hydrogel provides shaping and protection for the core during its curing process, and the shell is then removed to produce a thermochromic silicone rubber fiber. Because the thermochromic microcapsules are present within the fiber and are not easily detached, the fiber possesses stable thermochromic properties. Furthermore, the thermochromic silicone rubber fiber exhibits excellent mechanical properties, heat resistance, solvent resistance, corrosion resistance, and diverse thermochromic properties.

[0129] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a temperature-sensitive color-changing silicone rubber fiber, characterized in that: The following steps are involved: (1) mixing a silicone rubber prepolymer and a thermosensitive color-changing microcapsule to obtain a silicone rubber / thermosensitive color-changing microcapsule mixed prepolymer; (2) The silicone rubber / thermochromic microcapsule mixed prepolymer and hydrogel precursor solution obtained in step (1) are extruded through a coaxial spinning device to obtain core-shell fibers with the silicone rubber / thermochromic microcapsule mixed prepolymer as the core and the hydrogel as the shell. The core-shell fibers are then placed in a coagulation bath solution, cured, and the shell removed to obtain the thermochromic silicone rubber fibers.

2. The preparation method according to claim 1, characterized in that In step (1), the silicone rubber prepolymer includes at least one of a single-component silicone rubber prepolymer and a two-component cross-linked silicone rubber prepolymer.

3. The preparation method according to claim 1, characterized in that In step (1), the thermosensitive color-changing microcapsules include one or more thermosensitive color-changing microcapsules; and / or, in the silicone rubber / thermosensitive color-changing microcapsule mixed prepolymer, the thermosensitive color-changing microcapsules account for 1wt%-15wt%.

4. The preparation method according to claim 1, characterized in that In step (2), the hydrogel precursor solution includes at least one of an alginate aqueous solution, a polyacrylic acid aqueous solution, and a polyvinyl alcohol aqueous solution; and / or the coagulation bath solution includes at least one of a calcium salt aqueous solution, an aluminum salt aqueous solution, and a borax aqueous solution.

5. The preparation method according to claim 1, characterized in that In step (2), the coaxial spinning device includes an inner spinning head and an outer spinning head arranged coaxially, and the inner spinning head and the outer spinning head form an annular channel; the inner spinning head is connected to a first pushing device for extruding the silicone rubber / thermosensitive color-changing microcapsule mixed prepolymer through the inner spinning head; The outer spinning head is connected to a second pushing device for extruding the hydrogel precursor solution through the annular channel.

6. The preparation method according to claim 5, characterized in that The extrusion flow rate ratio of the silicone rubber / thermochromic microcapsule mixed prepolymer and the hydrogel precursor solution is (0.05-2):

1.

7. The preparation method according to claim 1, characterized in that In step (2), the core-shell fiber is placed in the coagulation bath solution to solidify the core of the core-shell fiber, and then the shell of the core-shell fiber is removed to obtain a linear temperature-sensitive color-changing silicone rubber fiber; Alternatively, the core-shell fiber is wound on a substrate to obtain a spiral core-shell fiber; then the whole is placed in the coagulation bath solution to solidify the core of the spiral core-shell fiber, and removed from the substrate, and then the outer shell of the spiral core-shell fiber is removed to obtain a spiral temperature-sensitive color-changing silicone rubber fiber.

8. The preparation method according to claim 7, characterized in that The process of removing the shell of the core-shell fiber is to place the solidified core-shell fiber in a shell removal solution for immersion; the shell removal solution includes at least one of a sodium citrate aqueous solution, an ethylenediaminetetraacetic acid aqueous solution, and a hydrochloric acid aqueous solution.

9. A temperature-sensitive color-changing silicone rubber fiber, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8.

10. A fabric or a component with temperature sensing function, characterized in that: The raw materials for preparing the fabric or the component with temperature sensing function include the temperature-sensitive color-changing silicone rubber fiber according to claim 9.

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