Phase change composite microcapsules, fast thermal management fabric and preparation method and application thereof

Abstract

The application discloses a phase change composite microcapsule, a rapid heat management fabric and a preparation method and application thereof. The phase change composite microcapsule with a thorn ball structure is prepared, and the attapulgite with a polarity significantly different from that of the phase change core material is introduced into the shell layer, so that the attapulgite is preferentially dispersed on the surface of the shell layer to form a super-high specific surface area heat conduction structure, and the heat conduction efficiency and the cycle stability are improved. Therefore, the microcapsule prepared by the application has good dispersibility and thermal stability, can be used for preparing a composite phase change fiber by melt spinning and woven into a fabric, realizes the unification of flexibility and high-temperature rapid heat management performance, and breaks through the limitation of low heat conduction efficiency and poor processing adaptability of traditional phase change materials.

Description

Technical Field

[0001] This invention belongs to the field of textile materials technology, specifically relating to a phase change composite microcapsule, a rapid thermal management fabric, its preparation method, and its application. Background Technology

[0002] High-temperature and drastic temperature difference environments are widespread in key industrial sectors such as textiles, electronics manufacturing, welding, and machining. Industrial equipment continuously releases a large amount of heat during operation. Without an effective thermal management system for insulation and temperature control, not only will equipment performance deteriorate and failure rates increase, but safety hazards may also arise. Especially when equipment operates continuously for extended periods or is subjected to cyclical temperature shocks, the thermal fatigue effect on materials and structures further exacerbates the risk of equipment failure. While existing traditional heat dissipation methods such as air cooling and water cooling are mature and widely used, they generally suffer from high structural rigidity, high energy consumption, and high maintenance costs, making it difficult to simultaneously meet the requirements of flexibility, lightweight design, and efficient heat conduction under high-temperature conditions.

[0003] With the upgrading of modern industrial technology, the requirements for thermal management systems in terms of response speed, temperature control accuracy, and adaptability are increasing. Phase change composite microcapsules, due to their advantages such as latent heat storage, phase change temperature regulation, and flexible processing, have become a research hotspot in the field of thermal management textiles in recent years. However, the phase change temperature ranges of commonly used phase change materials are mostly concentrated in the medium and low temperature ranges, making it difficult to meet the needs of rapid heat conduction and stable temperature control in high-temperature environments. At the same time, bottlenecks still exist in fabric structural design, heat conduction channel construction, and material interface heat transfer efficiency. Therefore, there is an urgent need to develop a thermal management fabric that combines flexible structure, high-temperature adaptability, and rapid heat conduction capabilities to provide efficient and reliable solutions for high-temperature thermal management in industrial equipment and other fields. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a phase change composite microcapsule, a rapid thermal management fabric, its preparation method, and its applications. This invention produces a spiky spherical phase change composite microcapsule. By introducing attapulgite clay with a significantly different polarity from the phase change core material into the shell layer, it preferentially disperses on the shell surface to form an ultra-high specific surface area thermally conductive structure, thereby improving thermal conductivity and cycle stability. Therefore, the microcapsules prepared by this invention possess good dispersibility and thermal stability, and can be used for melt spinning to prepare composite phase change fibers and weaving them into fabrics, achieving a balance between flexibility and high-temperature rapid thermal management performance, overcoming the limitations of low thermal conductivity and poor processing adaptability of traditional phase change materials.

[0005] The present invention adopts the following technical solution:

[0006] This invention provides a method for preparing phase change composite microcapsules, comprising the following steps:

[0007] Attapulgite clay and a dispersant are evenly dispersed in water to prepare an attapulgite clay aqueous suspension.

[0008] The phase change material, attapulgite soil water suspension, and emulsifier are mixed, stirred, and emulsified to obtain an emulsion;

[0009] Melamine and paraformaldehyde were added to water and reacted to obtain a prepolymer.

[0010] The prepolymer is added to the emulsion and reacted at a preset temperature. After the reaction is completed, post-treatment is performed to obtain phase change composite microcapsules. The dispersant is sodium tripolyphosphate, the phase change material is paraffin wax, and the emulsifier is sodium dodecyl sulfate.

[0011] Furthermore, in the preparation method of the phase change composite microcapsules, the concentration of the attapulgite water suspension is 1 wt.% to 5 wt.%.

[0012] Furthermore, in the preparation method of the phase change composite microcapsules, the emulsion is specifically prepared according to the following method: the phase change material is added to deionized water, attapulgite water suspension and emulsifier are added, and emulsification is carried out at a stirring speed of 3500 r / min for 15 to 30 min. The pH of the emulsion is adjusted to 4.5 to 5 to obtain the final product.

[0013] Furthermore, in the preparation method of the phase change composite microcapsules, the prepolymer is added dropwise to the emulsion at a rate of 1.2 mL / min, stirred, heated to 80 °C, and kept at that temperature for 1 h; then heated to 85 °C, kept at that temperature for 1 h, and the reaction is stopped. The pH of the solution is adjusted to 7, and the precipitate is filtered, washed, and dried to obtain the phase change composite microcapsules.

[0014] The present invention also provides a phase change composite microcapsule, which is prepared by the aforementioned method for preparing phase change composite microcapsules.

[0015] The present invention also provides a rapid thermal management fabric, which is prepared using the aforementioned phase change composite microcapsules as raw materials.

[0016] This invention also provides a method for preparing a rapid thermal management fabric, comprising the following steps: mixing and pulverizing the phase change composite microcapsules with a thermoplastic polymer matrix in a certain proportion, followed by melt extrusion granulation and melt spinning to obtain composite phase change fibers, and then weaving the obtained composite phase change fibers into fabric to obtain the rapid thermal management fabric; wherein the thermoplastic polymer matrix is ​​an ethylene-vinyl alcohol copolymer; and the amount of phase change composite microcapsules added is 5 wt.%.

[0017] This invention also provides the application of rapid thermal management fabrics in the field of high-temperature thermal management of industrial equipment and wearable systems.

[0018] The phase change composite microcapsules (AMPCM) prepared in this invention preferentially distribute ATP introduced into the shell layer on the outer surface of the shell, forming an ultra-high specific surface area spiky spherical microstructure with oriented inorganic nanorods. Due to the significant polarity difference and surface energy mismatch between ATP and the organic phase change core material, ATP preferentially disperses and adsorbs at the inorganic / organic interface. During in-situ polymerization, it is encapsulated and solidified by the resin shell layer, thereby constructing a protruding spiky spherical structure on the surface of the microcapsule. The spiky spherical shell structure of the AMPCM gives the microcapsules excellent dispersion stability and interfacial compatibility in the polymer matrix, effectively avoiding agglomeration and sedimentation during melt processing.

[0019] The phase change composite microcapsules (AMPCM) prepared in this invention construct abundant filler-phase change material contact interfaces internally, reducing interfacial thermal resistance and effectively improving the thermal conductivity of AMPCM. Simultaneously, ATP provides numerous heterogeneous nucleation sites for the microcapsules, thereby effectively promoting the crystallization of the phase change material and reducing supercooling. The spiky shell structure of the AMPCM enables the microcapsules to exhibit excellent dispersion stability and interfacial compatibility in the polymer matrix, effectively preventing agglomeration and sedimentation during melt processing.

[0020] The rapid thermal management fabric (PCMF fabric) of this invention retains good flexibility, breathability, and deformability after weaving, while also possessing high-efficiency thermal management performance and long-term stability. It can achieve efficient and sustained heat absorption and release under multiple temperature fluctuations. The AMPCM spiky spherical structure contained in the PCMF fabric can achieve phase change heat absorption and release in different temperature ranges by adjusting the type and mass ratio of phase change material. This allows the fabric to efficiently absorb and release heat in multiple temperature zones, thus possessing graded thermal management function and adjustable temperature response performance.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] First, the phase change composite microcapsules (AMPCM) prepared in this invention adopt a spiky spherical structure. The shell layer incorporates ATP to form an ultra-high specific surface area, constructing a dense and continuous thermally conductive network. Therefore, it effectively constructs multi-dimensional thermally conductive channels, enabling the phase change material to rapidly absorb and efficiently release heat during heating. Furthermore, the AMPCM shell structure is stable, and ATP enhances the interfacial bonding and thermal conductivity of the microcapsules, making them less prone to rupture or failure during multiple heating-cooling cycles.

[0023] Second, the phase change composite microcapsule AMPCM spike structure prepared by this invention has a high specific surface area and uniform surface spikes, making the microcapsules less prone to aggregation and easier to disperse. This characteristic allows AMPCM to be blended with a polymer matrix, making it suitable for melt spinning processes to prepare fibers, thereby producing uniformly distributed rapid thermal management fabrics (PCMF fabrics).

[0024] Third: The PCMF fabric prepared by this invention can maintain the original soft structure of the fibers, and the microcapsules are evenly distributed on the fiber surface, so that the fabric can still maintain thermal management function and morphological stability under various mechanical deformation conditions such as bending, stretching and twisting, making it suitable for complex curved surface structures and wearable system applications.

[0025] Fourth: The PCMF fabric prepared by this invention can achieve thermal response and thermal conductivity rate control at different temperatures by adjusting the type of phase change material, ATP content and spiky structure characteristics in AMPCM, providing an adjustable technical solution for the design of multi-temperature zone thermal management, graded heat absorption and release or intelligent temperature control fabrics. Attached Figure Description

[0026] Figure 1 These are SEM images of AMPCM-0 obtained in Example 1 and AMPCM-5 obtained in Example 6 of the present invention.

[0027] Depend on Figure 1 As shown in (a), AMPCM-0 exhibits a typical spherical microcapsule morphology with a smooth surface and uniform structure, while Figure 1 AMPCM-5 in (b) exhibits a significantly different multi-layered microstructure, with a rough and dense outer layer structure on its surface, giving AMPCM-5 a spiky structure and an ultra-high specific surface area.

[0028] Figure 2 This is a schematic diagram of the test sample of the rapid thermal management fabric of the present invention;

[0029] Figure 3 These are the high-temperature thermal management curves of the rapid thermal management fabric test samples from Examples 1 to 6 of the present invention;

[0030] Figure 4 These are the cyclic use curves of the rapid thermal management fabric test samples from Examples 1 to 6 of the present invention. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the embodiments.

[0032] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased.

[0033] Example 1

[0034] Add 12g of paraffin wax to 100ml of deionized water, then add 11.2g of sodium dodecyl sulfate (10 wt.%) as an emulsifier. Emulsify at 3500 r / min for 15 to 30 min. Finally, adjust the pH of the emulsion to 4.5-5 using a 20 wt.% citric acid solution.

[0035] 7.1 g of melamine, 4.9 g of paraformaldehyde, and 15.3 ml of deionized water were added to a beaker, and the pH of the system was adjusted to 8-9 using triethanolamine. The reaction was carried out at 70 °C for 30 min to obtain a clear and transparent liquid, namely the MF prepolymer. Subsequently, the MF prepolymer was added dropwise to the previously prepared emulsion at a pump rate of 1.2 mL / min, and mechanically stirred at 500 rpm / min. The temperature was raised to 80 °C and maintained for 1 h; then raised to 85 °C and maintained for 1 h before stopping the reaction. Finally, the pH of the solution was adjusted to approximately 7, and the precipitate was filtered, washed, and dried to obtain paraffin phase change microcapsules, named AMPCM-0.

[0036] The obtained AMPCM-0 was dried and then added to an ethylene-vinyl alcohol copolymer at a ratio of 5 wt.% in a high-speed mixer, stirred, and pulverized. Subsequently, it was melt-extruded and granulated using a micro twin-screw extruder. The operating temperatures of the preheating zone, melting zone, pressurizing zone, and die heating zone of the micro twin-screw extruder were 160 ℃, 175 ℃, 190 ℃, and 195 ℃, respectively. The resulting masterbatch was then melt-spun at the same temperature to prepare composite phase change fibers. The resulting composite phase change fibers were then woven into fabric, ultimately yielding a phase change composite fabric, denoted as PCMF-0.

[0037] Example 2

[0038] 0.24 g of attapulgite (ATP) and 0.012 g of sodium tripolyphosphate dispersant were mixed, ultrasonically dispersed and homogenized in 23.74 ml of deionized water to obtain a 1 wt.% ATP aqueous suspension. Then, 12 g of paraffin was added to 100 ml of deionized water, followed by the previously prepared 1 wt.% ATP aqueous suspension. The mixture was heated to 75 °C and emulsified at 3500 r / min for 15 min. Next, 13.6 g of sodium dodecyl sulfate emulsifier (10 wt.%) was added to the mixture, and emulsification continued at 3500 r / min for 15 min to obtain a Pickering emulsion. Finally, the pH of the Pickering emulsion was adjusted to 4.5-5 using a 20 wt.% citric acid solution.

[0039] 7.1 g of melamine, 4.9 g of paraformaldehyde, and 15.3 ml of deionized water were added to a beaker, and the pH of the system was adjusted to 8-9 using triethanolamine. The reaction was carried out at 70 °C for 30 min to obtain a clear and transparent liquid, namely the MF prepolymer. Subsequently, the MF prepolymer was added dropwise to the previously obtained Pickering emulsion at a pump rate of 1.2 mL / min, and mechanically stirred at 500 rpm / min. The temperature was raised to 80 °C and maintained for 1 h; then raised to 85 °C and maintained for 1 h before stopping the reaction. Finally, the pH of the solution was adjusted to approximately 7, and the precipitate was filtered, washed, and dried to obtain 1 wt.% ATP / paraffin phase change composite microcapsules, named AMPCM-1.

[0040] The obtained AMPCM-1 was dried and then added to an ethylene-vinyl alcohol copolymer at a ratio of 5 wt.% in a high-speed mixer, stirred, and pulverized. Subsequently, it was melt-extruded and granulated using a micro twin-screw extruder. The operating temperatures of the preheating zone, melting zone, pressurization zone, and die heating zone of the micro twin-screw extruder were 160 ℃, 175 ℃, 190 ℃, and 195 ℃, respectively. The resulting masterbatch was then melt-spun at the same temperature to prepare composite phase change fibers. The resulting composite fibers were then woven into fabrics, ultimately yielding a rapid thermal management fabric, denoted as PCMF-1.

[0041] Example 3

[0042] The only difference between this embodiment and Example 2 is that the amount of ATP added was adjusted to 0.48 g, and the amount of sodium tripolyphosphate dispersant was adjusted to 0.024 g. The ATP was dispersed in 23.5 ml of deionized water to obtain an ATP aqueous suspension with a mass fraction of 2 wt.%. The resulting microcapsules were named AMPCM-2, and the fabric was named PCMF-2.

[0043] Example 4

[0044] The only difference between this embodiment and Example 2 is that the amount of ATP added was adjusted to 0.72 g, and the sodium tripolyphosphate dispersant was 0.036 g. The ATP was then dissolved in approximately 23.2 ml of deionized water to prepare an ATP aqueous suspension with a mass fraction of 3 wt.%. The resulting microcapsules were named AMPCM-3, and the fabric was named PCMF-3.

[0045] Example 5

[0046] The only difference between this embodiment and Example 2 is that the amount of ATP added was adjusted to 0.96 g, and the amount of sodium tripolyphosphate dispersant was adjusted to 0.048 g. The ATP was then dissolved in approximately 23.0 ml of deionized water to prepare an ATP aqueous suspension with a mass fraction of 4 wt.%. The resulting microcapsules were named AMPCM-4, and the fabric was named PCMF-4.

[0047] Example 6

[0048] The only difference between this embodiment and Example 2 is that the amount of ATP added was adjusted to 1.2 g, and the sodium tripolyphosphate dispersant was 0.06 g. The ATP was then dissolved in approximately 22.7 ml of deionized water to obtain an ATP aqueous suspension with a mass fraction of 5 wt.%. The resulting microcapsules were named AMPCM-5, and the fabric was named PCMF-5.

[0049] High-temperature thermal management tests for PCMF-0 to PCMF-5:

[0050] like Figure 2 As shown, this invention uses a self-made experimental platform to test the high-temperature thermal management performance of fabrics. PCMF-0 to PCMF-5 samples were placed at the bottom of beakers, and 30 mL of boiling water was added to simulate a high-temperature heat source. A multi-channel temperature acquisition instrument was used to monitor the water temperature changes in real time. Simultaneously, the natural cooling of boiling water without any fabric covering in air and the covering of ordinary knitted fabric were used as controls. Figure 3 As shown, the times required to cool water to 40 °C were as follows: 2510 s for boiling water cooling naturally in air, 2760 s for ordinary knitted fabric, and 2670 s, 2180 s, 1760 s, 1560 s, 1210 s, and 1010 s for PCMF-0, PCMF-5, and PCMF-5, respectively. Compared to ordinary knitted fabric and PCMF-0 without phase change material, the other fabrics containing AMPCM showed a significantly faster cooling process, with PCMF-5 exhibiting the fastest cooling time, indicating that it has the most significant rapid heat conduction and efficient thermal management capabilities under high-temperature conditions.

[0051] Cyclic performance tests of PCMF-0 to PCMF-5:

[0052] Samples PCMF-0 through PCMF-5 were placed at the bottom of beakers, and 30 mL of boiling water was added to simulate a high-temperature environment. The boiling water was replaced every 300 seconds, and the cycle was repeated 5 times. A multi-channel temperature acquisition system was used to monitor the water temperature changes in real time to evaluate the thermal cycling temperature regulation performance of different PCMF samples. Simultaneously, uncovered boiling water was allowed to cool naturally, while samples covered with ordinary knitted fabric were used as controls. Figure 4As shown, during five high-temperature cycles, the average temperatures for boiling water cooled naturally in air, ordinary knitted fabric, and PCMF-0 to PCMF-5 were 62.9 ℃, 64.0 ℃, 63.3 ℃, 62.6 ℃, 61.7 ℃, 60.8 ℃, 59.9 ℃, and 58.6 ℃, respectively. Among these, PCMF-5 consistently exhibited lower temperatures and smaller temperature fluctuations throughout the cycles, demonstrating more stable thermal response behavior.

[0053] The above results show that PCMF-5 can still effectively exert its phase change temperature regulation function under multiple high-temperature cycling conditions, and has good cycling consistency and thermal management stability.

[0054] The above embodiments have provided a detailed description of the implementation methods of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. The above descriptions are merely preferred embodiments of the present invention and do not limit the scope of the present invention. All equivalent structural changes made based on the content of this specification are included within the scope of the present invention.

Claims

1. A method for preparing phase change composite microcapsules, characterized in that, Includes the following steps: Attapulgite clay and a dispersant are uniformly dispersed in water to prepare an aqueous suspension of attapulgite clay; the mass ratio of attapulgite clay to dispersant is 20:

1. The phase change material, attapulgite soil water suspension, and emulsifier are mixed, stirred, and emulsified to obtain an emulsion; Melamine and paraformaldehyde were added to water, the pH of the system was adjusted to 8-9, and the reaction was carried out at 70 °C for 30 min to obtain the prepolymer; the mass ratio of melamine, paraformaldehyde and water was 7.1:4.9:15.

3. The total mass of melamine and paraformaldehyde is equal to the mass of the phase change material; The prepolymer was added dropwise to the emulsion at a rate of 1.2 mL / min, stirred, heated to 80 °C, and kept at that temperature for 1 h. The temperature was then raised to 85 °C and held for 1 hour before the reaction was stopped. The pH of the solution was adjusted to 7, and the precipitate was filtered, washed, and dried to obtain the phase change composite microcapsules. The dispersant was sodium tripolyphosphate; the phase change material was paraffin wax; and the emulsifier was sodium dodecyl sulfate. The concentration of the attapulgite soil aqueous suspension is 1 wt.% to 5 wt.%. The emulsion is prepared by the following method: the phase change material is added to deionized water, attapulgite water suspension is added, the mixture is heated to 75 °C, stirred, emulsifier is added, and emulsification is carried out at a stirring speed of 3500 r / min for 15 to 30 min. The pH of the emulsion is adjusted to 4.5 to 5 to obtain the emulsion. The mass ratio of the phase change material to attapulgite is 50:

1.

2. A phase change composite microcapsule, characterized in that, The phase change composite microcapsules were prepared by the method described in claim 1.

3. A rapid thermal management fabric, characterized in that, It was prepared using the phase change composite microcapsules as described in claim 2 as raw material.

4. A method for preparing a rapid thermal management fabric, used to prepare the rapid thermal management fabric according to claim 3, characterized in that, The process includes the following steps: mixing and pulverizing the phase change composite microcapsules with a thermoplastic polymer matrix in a certain proportion, then melt-extruding and granulating the mixture, followed by melt spinning to obtain composite phase change fibers, and finally weaving the obtained composite phase change fibers into fabrics to obtain rapid thermal management fabrics. The thermoplastic polymer matrix is ​​an ethylene-vinyl alcohol copolymer; the amount of phase change composite microcapsules added is 5 wt.%.

5. The application of rapid thermal management fabrics in high-temperature thermal management of industrial equipment and wearable systems, characterized in that, Application based on the rapid thermal management fabric described in claim 3.

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