Flexible shape-stabilized phase change gel as well as preparation method and application thereof

Abstract

The invention discloses flexible shape-stabilized phase-change gel, a preparation method and application, the flexible shape-stabilized phase-change gel is mainly formed by compounding hydrogel and phase-change microgel, and the phase-change microgel is a phase-change oil gel emulsion formed by a phase-change material and a phase-change gelling agent under the action of an emulsifier; and uniformly dispersing the phase change oil gel emulsion and the hydrogel to obtain the flexible shape-stabilized phase change gel. The flexible shape-stabilized phase change gel and soft and elastic cloth are attached and sewn, and the cold and hot compress product capable of being used for human body physiotherapy is obtained. According to the flexible shape-stabilized phase change gel provided by the invention, through the fundamental innovation of a material structure and a compounding method, the core contradictions that the traditional PCM is insufficient in flexibility and easy to leak and the conventional hydrogel is limited in heat storage capacity are successfully solved, and an ideal solution is provided for advanced heat management application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of phase change gel, in particular to a flexible shape-fixing phase change gel, a preparation method and application thereof. BACKGROUND

[0002] Hydrogel is a kind of polymer material with three-dimensional network structure, which can absorb and retain a large amount of water without dissolving in water. Because of its soft texture, high water content and ability to maintain a certain shape, it becomes an ideal functional carrier. Cold and hot gel can quickly store and slowly release heat energy according to environmental temperature changes, realizing the intelligent physiotherapy of cold and hot dual use. However, such products have single function (usually only one of cold compress or hot compress), and the core functional material of the product, water or simple gel, has low energy storage density and limited heat preservation time, and there is still a lot of room for performance improvement. The isolation material coated outside the hydrogel is generally a film material that is impermeable to water and air, which does not fit well with the skin, and cannot achieve good fit in curved parts such as joints, resulting in poor user experience.

[0003] To pursue higher energy storage density and more intelligent temperature regulation capability, cold and hot gel combining phase change material (PCM) and hydrogel emerges as the times require. However, such advanced cold and hot gel materials and their application technology still face a series of severe challenges: (1) Leakage of phase change material is a serious problem: To improve the energy storage density, high content of phase change material (PCM) is often introduced into the hydrogel. However, PCM is accompanied by volume change during solid-liquid phase change, which can cause stress to the packaging material and lead to rupture. Liquid PCM has strong fluidity and is easy to migrate and leak from the gel network. Leakage not only leads to functional failure, but also may cause safety hazards and environmental pollution due to the heat release of solidification.

[0004] Traditional microcapsule packaging technology can alleviate leakage, but it needs multiple chemical synthesis and physical operation processes to control the thickness of the shell layer and the overall size, and the preparation process is complex, and the shell layer may affect the heat exchange efficiency. For example, CN117534931A solves the problems of traditional hydrogel in high tensile strength, compressibility and long cooling period by using a triple cross-linked structure in the hydrogel, combining PVA, PDMS and PCM, achieving high tensile strength, high compressibility and long cooling period. However, the invention cannot solve the problem of water loss of hydrogel, and in order to prevent PCM leakage, it uses expensive PCM microcapsule material, which is high in cost.

[0005] (2) Short cycle service life and poor water retention: Due to its high water content, gel material is prone to dryness during repeated cold and hot cycles, which leads to product size shrinkage, mechanical property degradation and thermal performance degradation, seriously affecting the use experience and product life, and greatly limiting its application range.

[0006] Phase change materials (PCM) can efficiently absorb, store and release a large amount of latent heat through its own solid-liquid phase change process, and show great application potential in thermal energy management, temperature constant control and other fields. Especially in the flexible wearable field such as human body thermal management, medical cold and hot compress, intelligent temperature regulating fabric, the demand for PCM is increasingly urgent.

[0007] However, the application of traditional PCM in the above flexible scenarios faces fundamental technical bottlenecks. The most common organic solid-liquid phase change material such as paraffin is in a solid state at room temperature, with a hard texture, which cannot be well fitted with irregular and dynamically changing human body surface, resulting in poor use comfort and low heat exchange efficiency, which seriously limits its application range. In order to improve the fit, the prior art attempts to emulsify PCM in water phase to form a soft phase change emulsion. However, PCM itself is a hydrophobic alkane, and it is difficult to obtain a high solid content and long-term stable emulsion system by direct emulsification, which has the risk of easy separation and emulsion breaking, affecting the reliability and heat storage capacity of the product.

[0008] Therefore, there is an urgent need in the art for a new phase change material that can balance high heat storage density, excellent flexibility and reliable morphological stability. The ideal material should be able to maintain the overall shape stable and not leak during the whole phase change process (especially when PCM is in liquid state), while having a soft texture similar to soft tissue to achieve close fitting with the human body. SUMMARY

[0009] In view of the deficiencies of the prior art, the purpose of the present application is to provide a flexible and shaped phase change gel which successfully solves the core contradictions of the lack of softness and easy leakage of traditional PCM and the limited heat storage capacity of conventional hydrogel by fundamental innovation of material structure and composite method, providing an ideal solution for advanced thermal management applications.

[0010] The technical scheme adopted by the present application to solve the technical problems is: a flexible and shaped phase change gel mainly composed of a hydrogel and a phase change microgel, wherein the phase change microgel is a phase change oil gel emulsion formed by a phase change material and a phase change gel agent under the action of an emulsifier; and the phase change oil gel emulsion and the hydrogel are uniformly dispersed to obtain the flexible and shaped phase change gel.

[0011] Further, the mass ratio of the hydrogel to the phase change microgel is 1-5:1.

[0012] Further, the hydrogel includes 15-30 parts by mass of monomers, 1-10 parts by mass of co-monomers, 0.01-0.5 parts by mass of crosslinking agents, 0.5-5 parts by mass of thickening agents, 0.1-0.5 parts by mass of initiators, and 40-70 parts by mass of solvents.

[0013] Further, the monomers include 15-30 parts by mass of first monomers and 0-10 parts by mass of second monomers.

[0014] Further, the phase change microgel comprises 10-60 parts of phase change material, 1.5-7 parts of emulsifier, 4-10 parts of emulsion stabilizer, 0.5-4 parts of phase change gel agent, and the balance of water.

[0015] The application also discloses a preparation method of the flexible shape phase change gel, which mainly comprises the following steps: Step 1), preparing the phase change microgel: Step 1a), the phase change material, the emulsion stabilizer and the phase change gel agent are added into a container and mixed, and then stirred and dissolved at 80-85 DEG C to form an oil phase; Step 1b), the water and the emulsifier are added into another container and mixed, and then stirred and dispersed at 80-85 DEG C to form an aqueous phase; Step 1c), the oil phase is slowly added into the aqueous phase under stirring at 80-85 DEG C after the aqueous phase is completely dissolved, and then the oil phase and the aqueous phase are completely mixed, and then homogenized, the homogenization speed is 1200-2000 rpm, and the emulsification time is 15-30 min; Step 1d), after the emulsification is completed, the stirring vacuum defoaming is carried out, the temperature is reduced to below the melting point of the phase change material, and then the phase change microgel is prepared after stirring uniformly; Step 2), preparing the hydrogel monomer solution: Step 2a), the second monomer and the solvent are mixed, and then the alkali is added to obtain a second monomer water mixed solution; Step 2b), the first monomer, the co-monomer, the crosslinking agent and the thickening agent are added into the second monomer water mixed solution and stirred uniformly to obtain a viscous monomer water solution; Step 3), the phase change microgel obtained in step 1) is added into the monomer water solution prepared in step 2) and stirred uniformly; Step 4), the initiator is added and mixed uniformly; Step 5), the mixed solution obtained in step 4) is added into a polymerization container, the reaction temperature is increased to 30-80 DEG C, and then polymerization is carried out to obtain the flexible shape phase change gel.

[0016] Further, in step 1), the phase change material is an organic phase change material, the phase change material is one or a mixture of more than two of alkane C n H 2n+2 with n=14-18; or the phase change material is an ester compound C m H 2m+1 COOCH3, C m H 2m+1One or more of COOC2H5 or a mixture of two or more of them; or the phase change material is a mixture of two or more of the alkane and the ester compound. The phase change gel is a styrene block copolymer (SBCs), including any one or a mixture of two or more of styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene-styrene (SIS), styrene-ethylene-propylene-styrene block copolymer (SEPS), polystyrene-polyethylene-polybutylene-polystyrene block copolymer, hydrogenated polystyrene-polyisoprene-polystyrene, and polystyrene-polyethylene-polypropylene block copolymer. The emulsifier is one or a mixture of two or three of sodium dodecyl sulfate, sodium dodecyl polyether sulfate, and sodium dodecyl benzene sulfonate. The emulsion stabilizer is one or a mixture of two or three of cetyl alcohol, stearyl alcohol, beeswax, and glycerol stearate.

[0017] Further, in step 2), the first monomer is a water-soluble non-ionic monomer, such as acrylamide, methacrylamide, hydroxyethyl acrylate, and hydroxyethyl methacrylate. The second monomer is a water-soluble ionic monomer, such as acrylic acid and its salt, methacrylic acid and its salt, and sodium styrene sulfonate. The acrylic acid and its salt are obtained by neutralizing acrylic acid with a base. The methacrylic acid and its salt are obtained by neutralizing methacrylic acid with a base. The base is any one or several of sodium hydroxide, potassium hydroxide, and aminomethylpropanol. The molar ratio of the acrylic acid or methacrylic acid to the base is 1:0.5-1.

[0018] The co-monomer terminal vinyl surfactant and the terminal vinyl polyethylene glycol are used. The terminal vinyl surfactant is a surfactant with a polymerizable vinyl group in the terminal group, such as VISIOMER® C18 PEG 1105 MAW, which is a long-chain polymerizable monomer with a hydrophilic block (25 ethylene oxide units) and a hydrophobic C16-18 alkyl end cap. The terminal vinyl polyethylene glycol is methoxy polyethylene glycol methacrylate (VISIOMER® MPEG 1005 MAW), APEG (allyl polyoxyethylene ether), TPEG (isopentenyl polyoxyethylene ether), and HPEG (methylallyl polyoxyethylene ether). The use of a terminal vinyl long-chain water-soluble monomer as a co-monomer can play the role of a dispersant and a surfactant, and improve the stability of the microgel in the hydrogel solution.

[0019] The solvent is a mixed solvent of water and alcohol with a weight ratio of 1:1 to 1:3. The alcohol is ethylene glycol, propylene glycol, glycerol, butanediol, or polyethylene glycol. The use of an alcohol and water mixture as a solvent in the hydrogel ensures that the moisture does not evaporate rapidly and in large quantities during use, and the appropriate alcohol and water ratio can ensure the dissolution of monomers and polymers and the stability of the hydrogel. On the other hand, alcohol can form a co-solvent with water to prevent moisture evaporation.

[0020] The crosslinking agent is one or a mixture of several of N,N'-methylenebisacrylamide, polyethylene glycol di(meth)acrylate, pentaerythritol triallyl ether, polyethylene glycol diglycidyl ether, and polyvalent metal salt.

[0021] The initiator is at least one of potassium persulfate, sodium persulfate, ammonium persulfate, an azo initiator, hydrogen peroxide, and an oxidation-reduction initiator.

[0022] The thickening agent is one or a mixture of several of hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, polysaccharide derivatives, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, polyethylene glycol, and polyvinyl pyrrolidone. The thickening agent can prevent the microgel from settling in the hydrogel monomer solution, improve the dispersibility of the microgel in the hydrogel monomer, and prepare a uniform multiple gel.

[0023] The application of a flexible shaped phase change gel involves the lamination of the flexible shaped phase change gel with soft and elastic fabric, and sewing to obtain a cold and hot compress product for human physical therapy.

[0024] Further, the cold and hot compress product includes, but is not limited to, a gel sleeve, a gel head cover, and a gel pad.

[0025] The flexible shaped phase change gel provided by the application is an advanced intelligent material prepared by compounding a phase change oil gel emulsion and a hydrogel matrix. The design concept is derived from the ingenious design of the material structure. First, the solid phase change material (PCM) is gelled and emulsified to form countless microgels with a three-dimensional network structure that can stably encapsulate the PCM, thereby preparing a phase change oil gel emulsion with high solid content and no leakage. Subsequently, these microgels are uniformly dispersed as functional units in a soft hydrogel network to ultimately form a multiple stable structure of "hydrogel containing oil gel".

[0026] This unique structure endows it with excellent comprehensive performance. Thanks to the characteristics of its hydrogel matrix, the material always maintains excellent softness, elasticity and moist touch, perfectly fits the human body curve and provides a comfortable user experience; fundamentally overcoming the poor fit of traditional solid PCM with the human body. At the same time, the high content of phase change microgel sealed inside it stores and releases a large amount of latent heat through solid-liquid phase change, realizes efficient energy storage and long-acting temperature control, significantly prolongs the duration of cold and hot compress, and makes up for the short board of ordinary hydrogel's limited heat storage capacity. More importantly, the gelation and double encapsulation technology completely solves the risk of leakage of traditional PCM in the phase change process, ensuring the cleanliness and reliability of the material throughout the use process.

[0027] In addition, the material also shows high designability. By adjusting the type of PCM, the concentration of microgel and the hydrogel network, its phase change temperature, mechanical strength and viscoelasticity can be accurately programmed to meet the specific needs of various scenarios from medical protective equipment, smart fabrics to electronic device thermal management. Therefore, the flexible fixed phase change gel successfully integrates multiple advantages such as high energy storage, long time effect, soft fit, shape stability, etc., and represents an important development direction of phase change materials in the application of medical devices and flexible wearable fields. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The water loss test results of the gels of some examples and comparative examples.

[0029] Figure 2 The temperature-time curves of the gels of some examples and comparative examples. DETAILED DESCRIPTION

[0030] The present application will be further described in conjunction with specific examples. However, these examples are only used to illustrate the present application and not to limit the scope of the present application.

[0031] Example 1 A method for preparing a flexible fixed phase change gel, comprising the following steps: Step 1) Preparation of phase change microgel: 30 parts of n-octadecane, 6 parts of a mixture of cetyl alcohol and stearyl alcohol, 1.5 parts of hydrogenated styrene-butadiene-styrene block copolymer (SEBS, model: Kraton G1651) were added to a beaker and slowly heated to 80-85°C to completely dissolve, obtaining an oil phase; 4 parts of sodium dodecyl sulfate and 40 parts of water were added to another beaker and slowly heated to 80-85°C to completely dissolve, obtaining an aqueous phase; the oil phase was slowly added to the stirring aqueous phase for emulsification and homogenization. After emulsification, the temperature was slowly lowered to 25°C to obtain the phase change microgel for standby.

[0032] Step 2) Preparation of hydrogel monomer solution Mix 7 parts of acrylic acid, 40 parts of glycerol, 20 parts of water, and add 3.2 parts of sodium hydroxide to obtain a mixed solution. Add 14 parts of acrylamide, 2 parts of polymerizable surfactant (VISIOMER® C18 PEG 1105 MAW), 0.15 parts of crosslinking agent N,N'-methylenebisacrylamide, and 3 parts of sodium carboxymethyl cellulose into the mixed solution, and stir to obtain a viscous monomer aqueous solution.

[0033] Step 3) Add 20 parts of the phase change microgel obtained in step 1) to 80 parts of the hydrogel monomer solution obtained in step 2), and stir to obtain a mixed solution. Step 4) Add 0.1 parts of potassium persulfate and 1 parts of water to obtain a mixed solution, and then add 0.1 parts of sodium bisulfite and 1 parts of water to obtain a mixed solution, and stir to obtain a mixed solution. Step 5) Add the mixed solution obtained in step 4) to a polymerization container (rectangular tank), and raise the reaction temperature to 50°C to obtain a flexible and shaped phase change gel.

[0034] Example 2 A method for preparing a flexible and shaped phase change gel, comprising the following steps: Steps 1) and 2) are the same as in Example 1. Step 3) Add 40 parts of the phase change microgel obtained in step 1) to 60 parts of the hydrogel monomer solution obtained in step 2), and stir to obtain a mixed solution. Step 4) Add 0.08 parts of potassium persulfate and 1 parts of water to obtain a mixed solution, and then add 0.08 parts of tetramethyl ethylenediamine and 1 parts of water to obtain a mixed solution, and stir to obtain a mixed solution. Step 5) Add the mixed solution obtained in step 4) to a polymerization container (rectangular tank), and raise the reaction temperature to 50°C to obtain a flexible and shaped phase change gel.

[0035] Example 3 A method for preparing a flexible and shaped phase change gel, comprising the following steps: Step 3) Add 50 parts of the phase change microgel obtained in step 1) to 50 parts of the hydrogel monomer solution obtained in step 2), and stir to obtain a mixed solution. The rest is the same as in Example 2.

[0036] Example 4 A method for preparing a flexible and shaped phase change gel, comprising the following steps: Step 2) wherein the glycerol is 30 parts, and the water is 30 parts.

[0037] The rest is the same as in Example 1.

[0038] Example 5 A method for preparing a flexible and shaped phase change gel, comprising the following steps: Step 2) wherein glycerol is 45 parts, water 15 parts. The rest is the same as Example 1.

[0039] Example 6 A method for preparing a flexible shape phase change gel, comprising the following steps: Step 1) Preparation of phase change microgel: Put 60 parts of n-hexadecane, 6 parts of a mixture of cetyl alcohol and stearyl alcohol, 1 part of beeswax, 3 parts of hydrogenated styrene-butadiene-styrene block copolymer (SEBS, type: Korten G1633) into a beaker, slowly heat to 80~85℃ to completely dissolve, get the oil phase; Put 5 parts of sodium dodecyl benzene sulfonate, 30 parts of water into another beaker, slowly heat to 80~85℃ to completely dissolve, get the water phase; Slowly add the oil phase into the stirring water phase, emulsify and homogenize. After emulsification is completed, slowly cool to 15℃, get the phase change microgel ready for use.

[0040] Step 2) Preparation of hydrogel monomer solution: Mix 5 parts of acrylic acid, 45 parts of glycerol, 15 parts of water, add 2 parts of sodium hydroxide to get a mixed solution. Add 20 parts of acrylamide, 5 parts of iso-pentenyl polyoxyethylene ether (TPEG), 0.2 parts of crosslinking agent polyethylene glycol diacrylate (PEG400), 5 parts of sodium carboxymethyl cellulose into the mixed solution, stir evenly to get a viscous monomer aqueous solution.

[0041] Step 3) Add 50 parts of phase change microgel obtained in step 1) into 50 parts of hydrogel monomer solution obtained in step 2), stir evenly; Step 4) Add 0.1 parts of potassium persulfate, 1 parts of water mixed solution, then add 0.1 parts of tetramethyl ethylenediamine, 1 parts of water mixed solution, stir evenly; Step 5) Put the mixed solution obtained in step 4) into a polymerization container (rectangular tank), raise the reaction temperature to 30~60℃, polymerize to get a flexible shape phase change gel.

[0042] Comparative Example 1 Step 2) wherein glycerol is 20 parts, water 40 parts. The rest is the same as Example 1.

[0043] Comparative Example 2 Mix 7 parts acrylic acid, 20 parts glycerol, and 40 parts water thoroughly, then add 3.2 parts sodium hydroxide to obtain a mixed solution. Add 14 parts acrylamide, 2 parts polymerizable surfactant (VISIOMER® C18 PEG 1105 MAW), 0.15 parts crosslinking agent N,N'-methylenediacrylamide, and 3 parts sodium carboxymethyl cellulose to the mixed solution and stir until homogeneous to obtain a viscous monomer aqueous solution. Add 0.1 parts potassium persulfate and 1 part water mixed solution, then add 0.1 parts sodium bisulfite and 1 part water mixed solution and stir until homogeneous. Pour the mixed solution into a polymerization container (rectangular trough), raise the reaction temperature to 50°C, and polymerize to obtain a flexible, shaped phase change gel.

[0044] Water loss test: The multiple gels prepared in Examples 1, 4, 5 and Comparative Example 1 were placed in a constant temperature and humidity chamber at 25°C and 65% humidity, and the weight change of the gels was tested at intervals.

[0045] Weight change rate (%) = gel weight / initial weight × 100% Water loss rate (%) = 1 - weight change rate (%) Test results are as follows Figure 1 As shown, the multiple gels prepared with different amounts of glycerol and water exhibited different water loss rates at room temperature. In Example 3, when the glycerol:water ratio in the hydrogel solution reached 3:1, the multiple gel not only did not lose water after one month, but also continuously absorbed moisture from the air at that humidity level, increasing its weight by approximately 10%. In Comparative Example 1, when the glycerol:water ratio in the hydrogel solution was 1:2, water was continuously lost over time, eventually reaching a loss rate of 32%. Simultaneously, the gel prepared in Comparative Example 1 lost its softness and exhibited slight oil seepage on its surface.

[0046] Cooling performance test: The multiple gel samples prepared in Examples 1-3 and Example 6, and the hydrogel prepared in Comparative Example 2, were placed in a refrigerator (0-4℃) for 12 hours and then simultaneously placed in a 35℃ incubator. A thermometer probe was placed inside each material to test the temperature changes. Temperature-time curves (such as...) were then analyzed. Figure 2 (As shown in the image) is used to characterize the product's cooling performance. From... Figure 2It can be seen that in Comparative Example 2, which does not contain phase change gel, the temperature gradually rises. Examples 1-3 contain different amounts of phase change gel, maintaining a certain plateau period near the phase change point temperature of the phase change gel. With the increase of the amount added, the plateau period gradually increases, the heat preservation time is prolonged, and the cooling performance is maintained near the phase change point. In Example 6, hexadecane is used as the phase change material. It can be seen that after maintaining near its phase change point for a period of time, the temperature gradually rises to the ambient temperature. This is because the temperature difference between the phase change point of hexadecane and the ambient temperature is large, so the heat preservation time is relatively short. The above results show that adding a high content of phase change microgel can achieve efficient energy storage and long-term temperature control through solid-liquid phase change storage and release of a large amount of latent heat, significantly extending the duration of hot and cold compresses.

[0047] Freezing performance test: The gels prepared in Examples 1-6 and Comparative Examples 1-2 were placed in the freezer compartment of a household refrigerator (-18°C) overnight, and the condition after freezing was observed. They were then thawed at room temperature.

[0048] Table 1

[0049] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the patent protection scope of the present invention should be defined by the claims.

Claims

1. A flexible, shape-stabilized phase change gel, characterized in that: It is mainly composed of hydrogel and phase change microgel. The phase change microgel is a phase change oil gel emulsion formed by phase change material and phase change gelling agent under the action of emulsifier. After the phase change oil gel emulsion and hydrogel are uniformly dispersed, a flexible and shaped phase change gel is obtained.

2. The flexible, shape-stabilized phase change gel as described in claim 1, characterized in that: The mass ratio of the hydrogel to the phase change microgel is 1~5:

1.

3. The flexible, shape-stabilized phase change gel as described in claim 1, characterized in that: The hydrogel comprises, by weight, 15-30 parts monomer, 1-10 parts comonomer, 0.01-0.5 parts crosslinking agent, 0.5-5 parts thickener, 0.1-0.5 parts initiator, and 40-70 parts solvent.

4. The flexible, shape-stabilized phase change gel as described in claim 3, characterized in that: The monomer comprises 15 to 30 parts by weight of a first monomer and 0 to 10 parts by weight of a second monomer.

5. The flexible, shape-stabilized phase change gel as described in claim 1, characterized in that: The phase change microgel comprises, by weight, 10-60 parts of phase change material, 1.5-7 parts of emulsifier, 4-10 parts of emulsion stabilizer, 0.5-4 parts of phase change gelling agent, and the balance being water.

6. The method for preparing the flexible, shape-stabilized phase change gel according to any one of claims 1 to 5, characterized in that: The preparation method mainly includes the following steps: Step 1), Preparation of phase change microgels: Step 1a) Add the phase change material, emulsion stabilizer, and phase change gelling agent to a container and mix them. Stir and melt the mixture at 80~85℃ to disperse it evenly and form an oil phase. Step 1b) Add water and emulsifier to another container and mix. Stir and disperse evenly at 80~85℃ to form an aqueous phase; Step 1c) After the aqueous phase is completely dissolved at 80~85℃, slowly add the completely dissolved oil phase while stirring. After the oil phase and aqueous phase are completely mixed, keep it at the temperature for homogenization at a speed of 1200~2000 rpm and an emulsification time of 15~30 min. Step 1d) After emulsification, stir and defoam under vacuum, cool down until the temperature is below the melting point of the phase change material, stir evenly and the phase change microgel is obtained. Step 2) Prepare the hydrogel monomer solution: Step 2a) Mix the second monomer and solvent, add alkali to neutralize, and obtain a water-soluble solution of the second monomer; Step 2b) Add the first monomer, comonomer, crosslinking agent, and thickener to the water-mixed solution of the second monomer, stir until homogeneous, and obtain a viscous monomer aqueous solution; Step 3) Add the phase change microgel obtained in step 1) to the monomer aqueous solution prepared in step 2) and stir until homogeneous; Step 4) Add the initiator and mix well; Step 5) Add the mixed solution obtained in Step 4) into the polymerization container, raise the reaction temperature to 30~80℃, and polymerize to obtain a flexible, shaped phase change gel.

7. The method for preparing a flexible, shape-stabilized phase change gel as described in claim 6, characterized in that: In step 1), the phase change material is an organic phase change material, and the phase change gelling agent is a styrene block copolymer (SBCs).

8. The method for preparing a flexible, shape-stabilized phase change gel as described in claim 6, characterized in that: In step 2), the first monomer is a water-soluble nonionic monomer, and the second monomer is a water-soluble ionic monomer; the comonomer is composed of a vinyl-terminated surfactant and a vinyl-terminated polyethylene glycol; the solvent is a water-alcohol mixture with a weight ratio of 1:1 to 1:

3.

9. The application of the flexible shape-stabilizing phase change gel as described in claim 1, characterized in that: Flexible, shape-fixed phase change gel is bonded to soft, elastic fabric and sewn together to obtain a hot and cold compress product that can be used for human physiotherapy.

10. The application of the flexible, shape-stabilized phase change gel as described in claim 9, characterized in that: The hot and cold compress products include, but are not limited to, gel sleeves, gel head covers, and gel pads.

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