Flexible Multi-level Phase Change Material Having Cross-linked Network Structure and Preparation Method Therefor
Patent Information
- Authority / Receiving Office
- IL · IL
- Patent Type
- Applications
- Current Assignee / Owner
- SICHUAN SANLIAN NEW MATERIAL CO LTD
- Filing Date
- 2020-08-19
- Publication Date
- 2026-07-01
AI Technical Summary
Existing phase change materials are prone to leakage during the phase change process. Traditional packaging methods are expensive to prepare and the materials are not flexible and processable. They only have a single phase transition, which limits their use range and temperature range cooling and temperature control effects.
Flexible multi-level phase change materials using a cross-linked network structure are prepared from phase change functional materials, cross-linked thermoplastic elastomers and thermoplastic resins through melt blending methods to form materials with multi-level phase transition temperatures. The cross-linked network is used to prevent phase change. Leakage of variable functional materials and their large-scale preparation through melt processing.
It achieves high energy storage density, excellent thermal stability and flexibility, and can cool and control temperature within a wide temperature range. It is suitable for aerospace, national defense and other fields, and maintains 40% to 95% of the energy storage of phase change functional materials. density.
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Abstract
Description
Flexible multi-stage phase change material with cross-linked network structure and preparation method thereof TECHNICAL FIELD
[0001] The present application belongs to the technical field of polymer composites, and particularly relates to a flexible multi-stage phase change material with a cross-linked network structure and a preparation method thereof. BACKGROUND
[0002] Effective thermal management is a prerequisite for ensuring the safety, reliability and service life of electronic devices. With the rapid development of aerospace, national defense and military industry, microelectronics, semiconductors and other fields, miniaturization and high integration have increased the heat energy per unit area of devices by several orders of magnitude, which has put higher requirements on the performance of thermal management materials. Phase change energy storage materials can store energy by absorbing a large amount of heat during the phase change process of the material, and are one of the most promising thermal management materials. Organic solid-liquid phase change materials represented by polyethylene glycol and paraffin have attracted widespread attention in the field of electronic device thermal management due to their high energy storage density, strong energy storage capacity, small supercooling degree, stable chemical properties, non-toxicity, non-corrosion, low price and other advantages. The biggest problem faced by organic phase change materials is that they are prone to leakage during the phase change process. The traditional solution is to encapsulate the phase change material in inorganic or metal three-dimensional porous materials, such as graphene aerogel, carbon foam, expanded graphite, nickel metal foam, etc. However, these inorganic or metal three-dimensional porous materials require complex preparation methods such as CVD, ice template, hydrothermal method, etc., which have high preparation cost and are difficult to achieve large-scale preparation and application. Moreover, these methods do not have flexibility and processability, making it difficult to prepare complex structures. At the same time, current traditional phase change materials generally only have a single phase transition, limiting the use range of phase change materials and the cooling and temperature control effect in a large temperature range. Therefore, it is of great significance to develop a flexible multi-stage phase change energy storage material that can be mass-produced, has high energy storage density, excellent thermal stability and low cost.
[0003] SUMMARY
[0004] In view of the above defects, the purpose of the present application is to provide a flexible phase change material and a preparation method thereof. The obtained flexible phase change material has a cross-linked network structure, and the phase transition temperature has multi-stage property. Moreover, the method of the flexible phase change material can realize large-scale industrial production.
[0005] The technical scheme of the present application is as follows:
[0006] The first technical problem to be solved by the present application is to provide a flexible phase change material, which is composed of the following components:
[0007] 20-90 parts by weight of phase change functional material,
[0008] 5-75 parts by weight of crosslinked thermoplastic elastomer,
[0009] 5-75 parts by weight of thermoplastic resin,
[0010] 0-5 parts by weight of compatibilizer.
[0011] Further, the flexible phase change material has a crosslinked network structure.
[0012] Further, the flexible phase change material has a multi-stage phase transition temperature, i.e. the flexible phase change material has at least two phase transition temperatures in the range of 10-200℃.
[0013] Further, the flexible phase change material is prepared by a method comprising: using phase change functional material, crosslinked thermoplastic elastomer, thermoplastic resin and compatibilizer as raw materials, and melting and blending each raw material, so that the melted phase change functional material enters into the crosslinked thermoplastic elastomer to swell it, and the crosslinked thermoplastic elastomer can prevent the leakage of the phase change functional material due to its polymer network, thereby obtaining the flexible phase change material.
[0014] Further, the phase change functional material is an organic phase change material or an inorganic phase change material.
[0015] Further, the organic phase change material is at least one of paraffin, polyol, alcohol polymer or carboxylic acid substance.
[0016] Preferably, the alcohol polymer is polyethylene glycol, the carboxylic acid substance is stearic acid, and the paraffin is liquid paraffin or solid paraffin.
[0017] Further, the thermoplastic elastomer in the crosslinked thermoplastic elastomer comprises one or more of ethylene-octene block copolymer (POE), ethylene-octene random copolymer (OBC), ethylene-propylene rubber (EPDM), polyurethane elastomer, styrene-butadiene-styrene block copolymer (SBS) and hydrogenated styrene-butadiene-styrene block copolymer (SEBS).
[0018] Further, the thermoplastic resin comprises at least one of low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), polybutylene (PB), polyvinyl acetate (PVAC), polystyrene (PS), polycarbonate (PC), polyamide (PA), polyurethane (PU) and polyvinylidene fluoride (PVDF). The addition of the thermoplastic resin can significantly improve the processing performance of the phase change material while providing multi-stage phase transition.
[0019] Further, the compatibilizer comprises one of maleic anhydride compatibilizer or acrylic compatibilizer.
[0020] The second technical problem to be solved by the present application is to provide a preparation method of the flexible phase change material, which comprises the following steps: taking phase change functional material, cross-linked thermoplastic elastomer, thermoplastic resin and compatibilizer as raw materials, and melting and blending the raw materials, so that the melted phase change functional material enters into the cross-linked thermoplastic elastomer to swell the cross-linked thermoplastic elastomer, and the cross-linked thermoplastic elastomer can prevent the leakage of the phase change functional material, thereby obtaining the flexible phase change material; wherein the weight ratio of the raw materials is as follows: 20-90 parts by weight of phase change functional material, 5-75 parts by weight of cross-linked thermoplastic elastomer, 5-75 parts by weight of thermoplastic resin, and 0-5 parts by weight of compatibilizer.
[0021] Further, in the preparation method, the temperature of melting and blending is above the melting point of the thermoplastic resin and below the thermal decomposition temperature.
[0022] Further, the preparation method comprises the following steps: melting and processing blending the phase change functional material, the cross-linked thermoplastic elastomer, the thermoplastic resin and the compatibilizer at 80-250 DEG C, and then extruding and granulating to obtain flexible phase change granules; and then processing and molding the flexible phase change granules to obtain the flexible phase change material.
[0023] Further, in the method, the processing and molding is performed by injection molding, casting or melt spinning.
[0024] Further, in the method, the cross-linked thermoplastic elastomer is prepared by irradiation cross-linking or adding a cross-linking agent.
[0025] Preferably, the cross-linked thermoplastic elastomer is prepared by adding a cross-linking agent, and the cross-linking agent comprises dicumyl peroxide, di-tert-butyl peroxide or t-butyl phenol formaldehyde resin; the cross-linking temperature is 120-190 DEG C, the cross-linking time is 0.5-10 minutes, and the content of the cross-linking agent is 0.1-5 phr.
[0026] The third technical problem to be solved by the present application is to provide a method for improving the thermal stability of phase change functional material, which comprises the following steps: introducing cross-linked thermoplastic elastomer and thermoplastic resin into the phase change functional material, and then preparing a flexible phase change material by melting and blending; wherein the weight ratio of the raw materials is as follows: 20-90 parts by weight of phase change functional material, 5-75 parts by weight of cross-linked thermoplastic elastomer, and 5-75 parts by weight of thermoplastic resin.
[0027] Further, in the method, a compatibilizer can be further added, and the content of the compatibilizer is 0.1-5 parts by weight.
[0028] The present application has the following advantages:
[0029] The flexible phase change material obtained by this invention has the following advantages: 1) superior thermal stability, as the cross-linked elastomer acts as a supporting material, giving the phase change material excellent thermal stability; 2) superior flexibility and processability, capable of being prepared into any desired shape, including fibers and films; and can be mass-produced using melt processing; 3) high energy storage density, maintaining 40% to 95% of the energy storage density of phase change functional materials. The flexible phase change material obtained by this invention can be applied in aerospace, defense, microelectronics, semiconductors, and other fields. Attached Figure Description
[0030] Figure 1 is a schematic diagram of the preparation method and structure of the flexible phase change material based on the "swelling" mechanism of the present invention. In the figure, 1 represents the uncrosslinked thermoplastic elastomer, 2 represents the chemical crosslinking point in the crosslinked thermoplastic elastomer, and 3 represents the phase change functional material swollen in the polymer crosslinking network. The preparation method of the flexible phase change material of the present invention utilizes the "swelling" mechanism. The phase change functional material molten at high temperature can enter the spaces between the crosslinked polymer molecular chains and cause it to swell. The binding effect of the crosslinked polymer network prevents the leakage of the phase change functional material, thereby improving the thermal stability.
[0031] Figure 2 is a SEM image of the cross-section of the flexible phase change material obtained in Example 1. The cross-section of the flexible phase change material was obtained by brittle fracture in liquid nitrogen and the cross-section was etched with chloroform. As can be seen from Figure 2, paraffin wax is uniformly distributed in the other polymer matrix as an "island phase".
[0032] Figure 3 shows the DSC heating curve of the flexible phase change material obtained in Example 1. As can be seen from Figure 3, Sample 1 has three phase transition temperatures, which are 40.01℃, 55.95℃ and 119.4℃, respectively, and its phase transition enthalpy is 138.9kJ / kg.
[0033] Figure 4 shows the thermal stability test of the flexible phase change material and the paraffin used in Example 1. As can be seen from Figure 4, when the phase change material obtained by the present invention is placed at a temperature of 160°C, it maintains a good shape and does not produce any leakage. Detailed Implementation
[0034] The first technical problem to be solved by this invention is to provide a flexible phase change material, which is composed of the following components:
[0035] 20-90 parts by weight of phase change functional materials
[0036] 5-75 parts by weight of cross-linked thermoplastic elastomer.
[0037] 5-75 parts by weight of thermoplastic resin,
[0038] Compatibilizer 0-5 parts by weight.
[0039] The phase transition temperature of the flexible phase change material has multiple stages, that is, the flexible phase change material has at least two phase transition temperatures in the range of 10-200 DEG C; the multiple phase change process is beneficial to improve the use range of the phase change material and the cooling and temperature control effect in a large temperature range.
[0040] The second technical problem to be solved by the present application is to provide a preparation method of the flexible phase change material, which comprises the following steps: taking a phase change functional material, a cross-linked thermoplastic elastomer, a thermoplastic resin and a compatibilizer as raw materials, and preparing the flexible phase change material by melting and blending the raw materials so that the melted phase change functional material enters the cross-linked thermoplastic elastomer to swell it; wherein the weight ratio of the raw materials is as follows: the phase change functional material 20-90 parts by weight, the cross-linked thermoplastic elastomer 5-75 parts by weight, the thermoplastic resin 5-75 parts by weight, and the compatibilizer 0-5 parts by weight.
[0041] The flexible phase change material provided by the present application has multiple phase transition temperatures in the range of 10-200 DEG C, and can be cooled in the temperature range of 100-200 DEG C. The composition comprises a phase change functional material, a cross-linked thermoplastic elastomer, a thermoplastic resin and a compatibilizer.
[0042] The present application utilizes the mechanism of "swelling" of the cross-linked thermoplastic elastomer by the melted phase change functional material to prepare the flexible phase change material. The dissolution process of the polymer has two stages, first, the solvent molecules penetrate into the polymer to swell the polymer, and then the polymer molecular chains are uniformly dispersed in the solvent. The cross-linked thermoplastic elastomer also swells when it is in contact with the melted phase change functional material, but due to the binding effect of the cross-linked network, the molecules of the melted phase change functional material cannot further break down the cross-linked molecular network and can only stay in the swelling stage. The present application utilizes this "swelling" mechanism to prepare the flexible phase change material, and the melted phase change functional material can enter between the cross-linked polymer molecular chains and swell at high temperature. The binding effect of the polymer network prevents the leakage of the phase change functional material and improves the thermal stability.
[0043] Example 1:
[0044] POE and DCP are first mixed in a mass ratio of 100:0.5, and then extruded and blended in a granulator at 160 DEG C to obtain the cross-linked POE thermoplastic elastomer.
[0045] The cross-linked POE, the granular paraffin with phase transition temperature of 58°C and the HDPE 6098 are melt-mixed at a mass ratio of 20:50:30, and are extruded and granulated in an extruder at 180°C to obtain phase change material granules; the phase change material granules are cast into a film (sample 1) on a casting equipment, and the casting temperature is 180°C, and the thickness of the obtained casting film can be controlled in a range of 0.01mm to 0.1mm.
[0046] The melting curve of the phase change material is measured by using a differential scanning calorimeter of TA Company, and FIG. 3 is a DSC heating curve of the flexible phase change material (sample 1) obtained in Example 1; as shown in FIG. 3, the sample 1 has three phase transition temperatures, which are 40.01°C, 55.95°C and 119.4°C respectively, and the phase change enthalpy value is 138.9kJ / kg; and the final energy storage density can keep about 80% of the phase change functional material. FIG. 4 is a thermal stability test of the flexible phase change material obtained in Example 1, and as shown in the figure, the phase change material is placed at a temperature of 160°C, and it keeps a good shape without any leakage phenomenon.
[0047] FIG. 2 is an SEM graph of the cross section of the flexible phase change material obtained in Example 1, and the cross section is obtained by quenching in liquid nitrogen, and the cross section is etched by chloroform; as shown in FIG. 2, the paraffin forms "island phase" and is uniformly distributed in the other polymer matrix.
[0048] Example 2:
[0049] The OBC and the DCP are mixed at a mass ratio of 100:0.3, and are extruded and granulated in an extruder at 160°C to obtain a cross-linked OBC thermoplastic elastomer.
[0050] The cross-linked OBC, the granular paraffin with phase transition temperature of 58°C and the PP are melt-mixed at a mass ratio of 10:60:30, and are extruded and granulated in an extruder at 190°C to obtain phase change material granules; the phase change material granules are injected into samples with specific sizes on an injection molding machine, and the injection molding temperature is 190°C.
[0051] The melting curve of the phase change material is measured by using a differential scanning calorimeter of TA Company, and the sample has three phase transition temperatures, which are 40.01°C, 55.95°C and 165.7°C respectively, and the phase change enthalpy value is 151.3kJ / kg; and the final energy storage density can keep about 90% of the phase change functional material. The phase change material is placed at a temperature of 160°C, and it keeps a good shape without any leakage phenomenon.
[0052] Example 3:
[0053] The SEBS and the DCP are mixed at a mass ratio of 100:0.5, and are extruded and granulated in an extruder at 160°C to obtain a cross-linked SEBS thermoplastic elastomer.
[0054] The cross-linked SEBS, the granular paraffin with phase transition temperature of 58℃ and the HDPE6098 are melt-mixed in a mass ratio of 20:60:20, and extruded and granulated in an extruder at 200℃ to obtain phase change material granules; the phase change material granules are injection molded into samples of specific size in an injection molding machine, and the injection molding temperature is 200℃.
[0055] The melting curve of the phase change material is measured by a differential scanning calorimeter of TA Company, the sample has three phase transition temperatures of 39.70℃, 56.13℃ and 120.1℃ respectively, the phase change enthalpy value is 150.1kJ / kg, and the final energy storage density can keep about 80% of the phase change functional material. The phase change material is placed at a temperature of 160℃, and it keeps a good shape without any leakage.
[0056] Example 4:
[0057] The OBC and the DCP are mixed in a mass ratio of 100:0.3, and extruded and granulated in an extruder at 160℃ to obtain a cross-linked OBC thermoplastic elastomer.
[0058] The cross-linked OBC, the PEG with phase transition temperature of 60℃, the HDPE6098 and the PP are melt-mixed in a mass ratio of 10:60:20:10, and extruded and granulated in an extruder at 190℃ to obtain phase change material granules; the phase change material granules are injection molded into samples of specific size in an injection molding machine, and the injection molding temperature is 190℃.
[0059] The melting curve of the phase change material is measured by a differential scanning calorimeter of TA Company, the sample has three phase transition temperatures of 60.01℃, 55.15℃ and 165.7℃ respectively, the phase change enthalpy value is 158.8kJ / kg, and the final energy storage density can keep about 90% of the phase change functional material. The phase change material is placed at a temperature of 160℃, and it keeps a good shape without any leakage.
[0060] Although the present application is described above in combination with the examples, it should be clear for those skilled in the art that various modifications can be made to the above examples without departing from the spirit and scope of the claims.
Claims
1. A flexible phase change material, characterized in that, The phase change material is composed of the following components: 20-90 parts by weight of phase change functional materials 5-75 parts by weight of cross-linked thermoplastic elastomer. 5-75 parts by weight of thermoplastic resin, Compatibilizer 0-5 parts by weight.
2. The flexible phase change material according to claim 1, characterized in that, The flexible phase change material has a cross-linked network structure.
3. The flexible phase change material according to claim 1 or 2, characterized in that, The flexible phase change material has a multi-level phase transition temperature, and has at least two phase transition temperatures in the range of 10℃ to 200℃.
4. The flexible phase change material according to any one of claims 1 to 3, characterized in that, The flexible phase change material is prepared by the following method: using phase change functional material, cross-linked thermoplastic elastomer, thermoplastic resin and compatibilizer as raw materials, the raw materials are melt-blended to allow the molten phase change functional material to enter the cross-linked thermoplastic elastomer and swell. The cross-linked thermoplastic elastomer, due to its polymer network, can prevent the leakage of phase change functional material, thus obtaining the flexible phase change material.
5. The flexible phase change material according to any one of claims 1 to 4, characterized in that, The phase change functional material is an organic phase change material or an inorganic phase change material.
6. The flexible phase change material according to claim 5, characterized in that, The organic phase change material is at least one of paraffin, polyol, alcohol polymer, or carboxylic acid.
7. The flexible phase change material according to claim 6, characterized in that, The alcohol polymer is polyethylene glycol, the carboxylic acid is stearic acid, and the paraffin is liquid or solid paraffin.
8. The flexible phase change material according to any one of claims 1 to 4, characterized in that, The thermoplastic elastomers in the crosslinked thermoplastic elastomers include one or more of the following: ethylene-octene block copolymers, ethylene-octene random copolymers, ethylene propylene rubber, polyurethane elastomers, styrene-butadiene-styrene block copolymers, and hydrogenated styrene-butadiene-styrene block copolymers.
9. The flexible phase change material according to any one of claims 1 to 4, characterized in that, The thermoplastic resin includes at least one of the following: low-density polyethylene, high-density polyethylene, polypropylene, polybutene, polyvinyl acetate, polystyrene, polycarbonate, polyamide, polyurethane, or polyvinylidene fluoride.
10. The flexible phase change material according to any one of claims 1 to 4, characterized in that, The compatibilizer includes one of maleic anhydride compatibilizers or acrylic compatibilizers.
11. A method for preparing the flexible phase change material according to any one of claims 1 to 10, characterized in that, The preparation method is as follows: using phase change functional material, cross-linked thermoplastic elastomer, thermoplastic resin and compatibilizer as raw materials, the raw materials are melt-blended so that the molten phase change functional material enters the cross-linked thermoplastic elastomer and swells. The cross-linked thermoplastic elastomer, due to its polymer network, can prevent the leakage of phase change functional material, thus obtaining the flexible phase change material; wherein, the weight ratio of each raw material is: 20-90 parts by weight of phase change functional material, 5-75 parts by weight of cross-linked thermoplastic elastomer, 5-75 parts by weight of thermoplastic resin, and 0-5 parts by weight of compatibilizer.
12. The method for preparing the flexible phase change material according to claim 11, characterized in that, In the preparation method, the melt blending temperature is above the melting point of the thermoplastic resin and below its thermal decomposition temperature.
13. The method for preparing the flexible phase change material according to claim 12, characterized in that, The preparation method is as follows: phase change functional material, cross-linked thermoplastic elastomer, thermoplastic resin and compatibilizer are melt-blended at 80℃~250℃, and then extruded and granulated to obtain flexible phase change granules; then processed and shaped to obtain flexible phase change material.
14. The method for preparing the flexible phase change material according to claim 13, characterized in that, The processing and molding are carried out by injection molding, casting, or melt spinning.
15. The method for preparing the flexible phase change material according to any one of claims 11 to 14, characterized in that, The crosslinked thermoplastic elastomer is prepared by radiation crosslinking or by adding a crosslinking agent.
16. The method for preparing the flexible phase change material according to claim 15, characterized in that, The crosslinked thermoplastic elastomer is crosslinked by adding a crosslinking agent, which is dicumyl peroxide, di-tert-butyl peroxide or tert-butylphenol resin, and the crosslinking agent content is 0.1 phr to 5 phr; the crosslinking temperature is 120℃ to 190℃, and the crosslinking time is 0.5 minutes to 10 minutes.
17. A method for improving the thermal stability of phase change functional materials, characterized in that, The method is as follows: cross-linked thermoplastic elastomer and thermoplastic resin are introduced into the phase change functional material, and then a flexible phase change material is prepared by melt blending; wherein, the weight ratio of each raw material is: 20-90 parts by weight of phase change functional material, 5-75 parts by weight of cross-linked thermoplastic elastomer, and 5-75 parts by weight of thermoplastic resin.
18. The method for improving the thermal stability of phase change functional materials according to claim 15, characterized in that, A compatibilizer can also be added, in an amount of 0.1 to 5 parts by weight.