Elastic phase change fiber and preparation method thereof

Abstract

The present invention discloses an elastic phase-change fiber and a preparation method thereof. A composite phase-change fiber having a core layer containing a phase-change material and an outer layer of a polymer layer is first prepared. The composite phase-change fiber is heat-treated and then cooled. Starting from one end, nodes are then provided at intervals of length. The fiber is bent at the nodes to break the fiber core at the nodes. The fiber is then stretched to obtain the elastic phase-change fiber. The elastic phase-change fiber obtained by the present invention has excellent elasticity and flexibility. After bending and winding, it can maintain a good phase-change material encapsulation effect and the integrity of the fiber structure. Fabrics woven with the phase-change composite fiber have excellent flexibility and elasticity, and have great application potential in areas of the human body that require bending and winding, such as joints.

Description

Technical Field

[0001] The present invention relates to the technical field of textile materials, and in particular to an elastic phase change fiber and a preparation method thereof. Background Art

[0002] Clothing plays a vital role in maintaining the body's thermal equilibrium, making it an integral part of daily life. The body typically adapts to changes in ambient temperature by adding or removing clothing, a process that is inconvenient. Thermoregulating smart fabrics can effectively respond to various external environmental stimuli, such as solar radiation and electrical energy, reducing the need for additional clothing while maintaining the body's necessary thermal balance. Therefore, advances in smart fabrics with temperature-regulating capabilities are crucial for promoting sustainability.

[0003] The development of phase change composite fibers (PCFs) has become a prominent research hotspot in the field of clothing technology. The key component of PCFs is phase change materials (PCMs), which can be categorized as organic, inorganic, and eutectic compounds. Organic PCMs are ideal for low- and mid-range thermal energy storage applications. Paraffin, n-eicosane, and n-hexadecane, among other organic PCMs, have attracted widespread attention due to their low cost, negligible supercooling, nontoxicity, good chemical stability, high energy storage density, and suitable phase transition temperatures. However, common organic PCMs are solid-liquid transition materials, which are prone to leakage in practical use, compromising product quality. Therefore, the encapsulation of PCMs has become a significant challenge in the application of PCFs. Encapsulating the PCM within a polymer—forming a composite fiber with an outer polymer layer enclosing an inner layer containing the PCM—can mitigate leakage to a certain extent. However, common PCFs and fabrics woven with them lack flexibility and elasticity, making them unsuitable for use on human joints. In particular, bending or winding phase-change composite fibers can easily puncture the outer polymer layer due to the rigidity of the phase-change material in its solid state. Therefore, developing phase-change composite fibers that are elastic, flexible, and non-leakage-resistant is of great significance to the development of smart fabrics. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes an elastic phase change fiber and a preparation method thereof.

[0005] The present invention provides a method for preparing an elastic phase change fiber, comprising the following steps:

[0006] S1. Inputting a core layer emulsion containing a phase change material and a shell layer solution containing a polymer into the inner and outer layers of a coaxial needle, respectively, and extruding the fibers through the needle into a water coagulation bath. After soaking the obtained fibers in water, the fibers are taken out and then soaked in ethanol or warm water, and dried.

[0007] S2. The fiber obtained in S1 is heat-treated and then cooled. Then, starting from one end, a node is set at every certain length. The fiber is bent at the node so that the inner core of the fiber is broken at the node. The fiber is then stretched to obtain an elastic phase change fiber.

[0008] Preferably, in S2, the temperature of the heat treatment is 60-80°C.

[0009] Preferably, in S2, the strain range of the stretching treatment is 30-80%.

[0010] Preferably, in S2, a node is provided every 0.4-2 mm in length.

[0011] Preferably, the core layer emulsion containing phase change material comprises, by mass percentage, 15-40% phase change material, 4-8% surfactant, 0.5-1.5% sodium alginate, and the balance water.

[0012] Preferably, the phase change material is at least one of paraffin, n-eicosane, and n-hexadecane.

[0013] Preferably, the surfactant is a combination of Span 80 and Tween 80. Preferably, the surfactant is composed of Span 80 and Tween 80 in a mass ratio of (0.4-0.5): (0.5-0.6).

[0014] Preferably, the preparation method of the core layer emulsion containing phase change material is as follows: the phase change material is mixed with a surfactant, heated and melted, and then stirred evenly to obtain an oil phase solution; under heat preservation conditions, water is added dropwise to the oil phase solution and stirred, and after the addition is completed, stirring is continued for a period of time, and then placed in an ice-water mixed bath for cooling, and then sodium alginate is added at room temperature to fully dissolve, thereby obtaining the product.

[0015] Preferably, in the method for preparing the core layer emulsion containing phase change material, the heating and melting temperature is 80-90°C.

[0016] Preferably, in the method for preparing the core layer emulsion containing the phase change material, the emulsion is heated and melted and then stirred for 5-10 minutes.

[0017] Preferably, in the method for preparing the core layer emulsion containing phase change material, stirring is continued for 10-30 minutes after the dropwise addition is completed.

[0018] Preferably, in the method for preparing the core layer emulsion containing phase change material, the core layer emulsion is placed in an ice-water mixed bath for cooling for 10-20 minutes.

[0019] Preferably, the polymer-containing shell solution comprises, by mass percentage, 12-20% polymer, 3-10% metal salt coagulant, and the balance being an organic solvent.

[0020] Preferably, the polymer is at least one of thermoplastic polyurethane, thermoplastic polyester elastomer, polyester, and spandex.

[0021] Preferably, the metal salt coagulant is at least one of a soluble calcium salt, a soluble nickel salt, a soluble copper salt, and a soluble cobalt salt. Preferably, the metal salt coagulant is at least one of Ca(NO3)2, Ni(NO3)2, Cu(NO3)2, Co(NO3)2, CaCl2, NiCl2, CuCl2, and CoCl2.

[0022] Preferably, the organic solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0023] In the present invention, by adding sodium alginate to the phase change emulsion and adding a metal salt coagulant to the polymer solution, the phase change material can be further stably encapsulated in the core layer of the fiber through the solidification of sodium alginate, making it less likely to leak, thereby improving the shape stability of the core layer and preventing the fiber from deforming as the phase change material melts and solidifies.

[0024] Preferably, in S1, the ratio of the extrusion rate of the core layer emulsion containing the phase change material to the shell layer solution containing the polymer is (1-3):1.

[0025] Preferably, in S1, the temperature of the water coagulation bath is 10-30°C.

[0026] Preferably, in S1, the fiber is immersed in water for 5-15 minutes.

[0027] Preferably, in S1, the soaking time in ethanol or warm water is 1-12 hours. The purpose of soaking in ethanol is to remove the surfactant in the fiber. Preferably, the temperature of the warm water is 25-40°C.

[0028] An elastic phase-change fiber is prepared by the preparation method.

[0029] The beneficial effects of the present invention are as follows:

[0030] The present invention first produces a composite phase change fiber with a core layer containing a phase change material and an outer layer of a polymer layer. After the composite phase change fiber is heat-treated and cooled, a node is set at each length starting from one end. The fiber is bent at the node so that the fiber core breaks at the node. The fiber is then stretched and retracted to obtain an elastic phase change fiber. The present invention forms multiple phase change material-polymer-phase change material repeating unit structures in the core of the fiber by first breaking the fiber core multiple times and then stretching it. While giving the fiber excellent elasticity, it also significantly improves the flexibility of the fiber, so that it can maintain a good phase change material encapsulation effect and the integrity of the fiber structure after bending and winding. As a result, the fabric woven with the phase change composite fiber has excellent flexibility and elasticity, and has great application potential in parts of the human body that require bending and winding, such as joints.

[0031] The present invention also adds sodium alginate to the phase change emulsion and a metal salt coagulant to the polymer solution. Through the solidification of sodium alginate, the phase change material can be further stably encapsulated in the core layer of the fiber, making it less likely to leak, thereby improving the shape stability of the core layer and preventing the fiber from deforming as the phase change material melts and solidifies. This results in a phase change composite fiber that is elastic, flexible, and not prone to leakage or deformation, which is of great significance to the development of smart fabrics. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 These are optical microscope photos of the fiber in Example 1 of the present invention before and after stretching.

[0033] Figure 2 This is the stress-strain curve of the elastic phase change fiber prepared in Example 1 of the present invention.

[0034] Figure 3 This is the cyclic stress-strain curve of the elastic phase change fiber prepared in Example 1 of the present invention.

[0035] Figure 4 This is a photograph of the elastic phase change fiber prepared in Example 1 of the present invention woven into a fabric and then wound around a gel pen refill.

[0036] Figure 5 This is an infrared photograph of the elastic phase change fiber prepared in Example 1 of the present invention, which was woven into a fabric and inscribed with "AUST" with a black marker, and then stretched and retracted under light irradiation.

[0037] Figure 6 This is an infrared photograph of the elastic phase change fiber prepared in Example 1 of the present invention being woven into a fabric, coated with liquid metal on the surface, and then stretched and retracted under electrical heating. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is described in detail below through specific embodiments.

[0039] Example 1

[0040] Preparation of core layer emulsion containing phase change material:

[0041] Solid paraffin and a surfactant (the surfactant consists of Span 80 and Tween 80 in a mass ratio of 0.46:0.54) are mixed, heated to melt at 80°C, and magnetically stirred for 5 minutes to obtain an oil phase solution; deionized water is added dropwise to the oil phase solution at a rate of 1 ml / min while being kept at 80°C and stirred. After the addition is complete, stirring is continued for 10 minutes, and then the mixture is placed in an ice-water mixed bath at 0°C and cooled for 10 minutes. Then, sodium alginate is added at room temperature and stirred for 1 hour to fully dissolve, thereby obtaining a core layer emulsion containing a phase change material;

[0042] The core layer emulsion containing the phase change material prepared above comprises, by mass percentage, 20% solid paraffin, 4% surfactant, 1% sodium alginate, and 75% deionized water.

[0043] Prepare the polymer-containing shell solution:

[0044] Thermoplastic polyurethane (TPU) particles are dissolved in N,N-dimethylformamide (DMF) solvent, and then Ca(NO3)2 is added and stirred to fully dissolve to obtain a polymer-containing shell solution;

[0045] The polymer-containing shell solution prepared above comprises, by mass percentage, 15% TPU, 27% Ca(NO 3 ), and 78% solvent DMF.

[0046] Preparation of phase change fibers:

[0047] S1. A core layer emulsion containing a phase change material and a shell layer solution containing a polymer are respectively introduced into the inner and outer layers of a coaxial needle through two 10 mL syringes, and then extruded through the needle into a deionized water coagulation bath at 25°C. The extrusion rate ratio of the core layer emulsion containing a phase change material to the shell layer solution containing a polymer is 1.75:1. After extrusion for 8 minutes, the obtained fiber is further soaked in water for 10 minutes. The fiber is removed, soaked in anhydrous ethanol for 3 hours, and then dried.

[0048] S2. The fiber obtained in S1 is heat-treated at 80°C for 10 minutes, cooled, and then a node is set every 1.0 mm from one end. The fiber is bent at the node so that the inner core of the fiber breaks at the node. The fiber is then stretched under 50% strain to obtain an elastic phase change fiber.

[0049] Figure 1These are optical microscope photos of the fibers in Example 1 before and after stretching. Figure 1 In the figure, the top picture is the picture of the fiber before stretching, and the bottom picture is the picture of the fiber after stretching. Figure 1 It can be seen that after the phase change fiber is subjected to the core breaking treatment, a uniform phase change material-polymer-phase change material repeating structure can be seen after stretching.

[0050] Figure 2 is the stress-strain curve of the elastic phase change fiber obtained in Example 1. Figure 2 It can be seen that the phase change fiber has good elasticity.

[0051] Figure 3 is the cyclic stress-strain curve of the elastic phase change fiber obtained in Example 1. Figure 3 It can be seen that the phase change fiber has good elastic stability.

[0052] Figure 4 This is a photo of the elastic phase change fiber prepared in Example 1 being woven into a fabric and then wound around a gel pen core. Figure 4 It can be seen that the phase change fabric can be wound around the pen refill, indicating its good flexibility. However, the phase change fiber that has not been heat-treated, broken, or stretched has very poor flexibility and cannot be wound around the pen refill. If it is forced to be wound, the inner core of the fiber will break and pierce the shell, thus destroying the fiber structure.

[0053] Figure 5 This is an infrared photograph of the elastic phase change fiber prepared in Example 1, woven into a fabric and marked with "AUST" in black marker, and then stretched and retracted under light irradiation. Figure 5 It can be seen that under light, the stretched fabric gradually returns to its initial state as the strain decreases.

[0054] Figure 6 This is an infrared photograph of the elastic phase change fiber prepared in Example 1 being woven into a fabric, coated with liquid metal on the surface, and then stretched and retracted under electrical heating. Figure 6 It can be seen that the woven fabric has good elasticity and resilience when powered on.

[0055] Example 2

[0056] Preparation of core layer emulsion containing phase change material:

[0057] Solid paraffin and a surfactant (the surfactant consists of Span 80 and Tween 80 in a mass ratio of 0.46:0.54) are mixed, heated to melt at 80°C, and magnetically stirred for 5 minutes to obtain an oil phase solution; deionized water is added dropwise to the oil phase solution at a rate of 1 ml / min while being kept at 80°C and stirred. After the addition is complete, stirring is continued for 10 minutes, and then the mixture is placed in an ice-water mixed bath at 0°C and cooled for 10 minutes. Then, sodium alginate is added at room temperature and stirred for 1 hour to fully dissolve, thereby obtaining a core layer emulsion containing a phase change material;

[0058] The core layer emulsion containing the phase change material prepared above comprises, by mass percentage, 20% solid paraffin, 4% surfactant, 1% sodium alginate, and 75% deionized water.

[0059] Prepare the polymer-containing shell solution:

[0060] Thermoplastic polyester elastomer (TPEE) particles were dissolved in N,N-dimethylacetamide (DMAC) solvent, and then Cu(NO3)2 was added and stirred to fully dissolve to obtain a polymer-containing shell solution;

[0061] The polymer-containing shell solution prepared above comprises, by mass percentage, 15% TPEE, 27% Cu(NO 3 ), and 78% solvent DMF.

[0062] Preparation of phase change fibers:

[0063] S1. The core layer emulsion containing the phase change material and the shell layer solution containing the polymer are respectively introduced into the inner and outer layers of a coaxial needle through two 10 mL syringes, and then squeezed into a 25°C deionized water coagulation bath through the needle. The extrusion rate ratio of the core layer emulsion containing the phase change material to the shell layer solution containing the polymer is 2:1. The obtained fiber is further soaked in water for 10 minutes, the fiber is removed, and then soaked in anhydrous ethanol for 3 hours and dried.

[0064] S2. The fiber obtained in S1 is heat-treated at 80°C for 10 minutes, cooled, and then, starting from one end, a node is set every 0.6 mm. The fiber is bent at the node so that the inner core of the fiber breaks at the node. The fiber is then stretched under a strain of 40% to obtain an elastic phase change fiber.

[0065] Example 3

[0066] Preparation of core layer emulsion containing phase change material:

[0067] n-Eicosane and a surfactant (the surfactant consists of Span 80 and Tween 80 in a mass ratio of 0.46:0.54) were mixed, heated to melt at 85°C, and magnetically stirred for 10 minutes. Deionized water was added dropwise to the oil phase solution at a rate of 1 ml / min while being kept at 85°C and stirred. After the addition was complete, stirring was continued for 10 minutes, and then the mixture was placed in an ice-water mixed bath at 0°C and cooled for 10 minutes. Then, sodium alginate was added at room temperature and stirred for 1 hour to fully dissolve it, thereby obtaining a core layer emulsion containing a phase change material;

[0068] Wherein, the core layer emulsion containing phase change material prepared above comprises, by mass percentage: 20% n-eicosane, 5% surfactant, 1% sodium alginate, and 75% deionized water.

[0069] Prepare the polymer-containing shell solution:

[0070] Spandex (SP) particles were dissolved in DMF solvent, and then Ca(NO3)2 was added and stirred to fully dissolve to obtain a polymer-containing shell solution;

[0071] The polymer-containing shell solution prepared above comprises, by mass percentage, 15% SP, 27% Ca(NO 3 ), and 78% solvent DMF.

[0072] Preparation of phase change fibers:

[0073] S1. A core layer emulsion containing a phase change material and a shell layer solution containing a polymer are respectively introduced into the inner and outer layers of a coaxial needle through two 10 mL syringes, and then squeezed into a 25°C deionized water coagulation bath through the needle. The extrusion rate ratio of the core layer emulsion containing a phase change material to the shell layer solution containing a polymer is 2:1. After extrusion for 8 minutes, the obtained fiber is soaked in water for a further 10 minutes. The fiber is taken out and soaked in warm water for a further 6 hours, and then dried.

[0074] S2. The fiber obtained in S1 is heat-treated at 70°C for 10 minutes, cooled, and then, starting from one end, a node is set every 0.4 mm. The fiber is bent at the node so that the inner core of the fiber breaks at the node. The fiber is then stretched under 50% strain to obtain an elastic phase change fiber.

[0075] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing an elastic phase change fiber, characterized in that: The following steps are involved: S1. Inputting a core layer emulsion containing a phase change material and a shell layer solution containing a polymer into the inner and outer layers of a coaxial needle, respectively, and extruding the fibers through the needle into a water coagulation bath. After soaking the obtained fibers in water, the fibers are taken out and then soaked in ethanol or warm water, and dried. The core layer emulsion containing the phase change material comprises, by mass percentage, 15-40% of the phase change material, 4-8% of the surfactant, 0.5-1.5% of the sodium alginate, and the balance being water; the phase change material is at least one of paraffin, n-eicosane, and n-hexadecane; The polymer-containing shell solution comprises, by mass percentage, 12-20% of polymer, 3-10% of metal salt coagulant, and the balance being an organic solvent; S2. The fiber obtained in S1 is heat-treated and then cooled. Then, starting from one end, a node is set at every certain length. The fiber is bent at the node so that the inner core of the fiber is broken at the node. The fiber is then stretched to obtain an elastic phase change fiber.

2. The method for preparing the elastic phase change fiber according to claim 1, characterized in that: In S2, the temperature of the heat treatment is 60-80°C.

3. The method for preparing the elastic phase change fiber according to claim 1, characterized in that: In S2, the strain range of the stretching treatment is 30-80%.

4. The method for preparing the elastic phase change fiber according to claim 1, characterized in that: In S2, a node is set every 0.4-2 mm.

5. The method for preparing the elastic phase change fiber according to claim 1, characterized in that: The polymer is at least one of thermoplastic polyurethane, thermoplastic polyester elastomer, polyester, and spandex; The metal salt coagulant is at least one of a soluble calcium salt, a soluble nickel salt, a soluble copper salt, and a soluble cobalt salt. The organic solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

6. The method for preparing the elastic phase change fiber according to claim 1, characterized in that: In S1, the ratio of the extrusion rate of the core layer emulsion containing the phase change material to the shell layer solution containing the polymer is (1-3):

1.

7. An elastic phase change fiber, characterized in that: Prepared by the preparation method according to any one of claims 1 to 6.

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