High-temperature-resistant and recyclable TPEE film as well as preparation method and application thereof

Abstract

The invention relates to a high-temperature-resistant and recyclable TPEE film as well as a preparation method and application thereof, and belongs to the technical field of high-performance environment-friendly high polymer materials. The thermoplastic polyester elastomer composite material is composed of thermoplastic polyester elastomer (TPEE) matrix resin, a high-temperature-resistant reinforcing filler, a high-thermal-stability auxiliary agent and a recycled compatilizer. The TPEE resin with a specific structure is selected to be compounded with the high-temperature-resistant inorganic filler, and an efficient thermal stability and hydrolysis resistance system is introduced, so that the thermal deformation temperature (HDT) and the long-term thermal aging performance of the film are remarkably improved, and meanwhile, the thermoplastic nature of the TPEE is kept, so that excellent recyclability is realized. The mechanical property retention rate of the film after long-term use at 180 DEG C is greater than or equal to 85%, and the key performance attenuation rate of the film after at least three times of melting recovery processing is less than 15%, so that the technical problem that the material cannot be recovered due to traditional high-temperature-resistant modification is successfully solved. The film is particularly suitable for the fields of new energy automobile battery assembly insulation, high-temperature electronic tags, recyclable environment-friendly packaging, heat-resistant special fabrics and the like.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, and in particular to a high-temperature resistant and recyclable TPEE membrane, its preparation method, and its application. Background Technology

[0002] Thermoplastic polyester elastomer (TPEE) is a block copolymer with excellent mechanical strength, elasticity, oil resistance, and fatigue resistance, and is widely used in the automotive, electronics, and wire and cable industries. With continuous technological advancements and expanding application scenarios, especially the rise of high-end fields such as new energy vehicles and aerospace, higher demands are being placed on the high-temperature resistance of TPEE materials. For example, in new energy vehicles, the insulating materials surrounding the power battery need to withstand certain operating temperatures over a long period and be able to withstand higher temperature shocks in a short time. This makes improving the high-temperature resistance of TPEE materials an important research direction in the field of polymer materials, and it is of great significance for promoting the development of related high-end industries.

[0003] Traditional methods for improving the heat resistance of TPEE mainly include the following: First, increasing the content of hard segment (PBT) or selecting hard segments with higher melting points to enhance the material's heat resistance. Second, adding inorganic heat-resistant fillers, such as glass fiber and mica, utilizing their properties to increase the material's heat distortion temperature. Third, introducing cross-linked structures to improve the material's heat resistance. These methods can improve the heat resistance of TPEE to some extent and have achieved certain results in past applications, providing some ideas and approaches for solving the heat resistance problem of TPEE.

[0004] However, these traditional methods have significant drawbacks. Increasing the hard segment content sacrifices the material's flexibility, rendering it unusable in applications requiring flexibility. While adding conventional fillers can increase the heat distortion temperature, it often leads to embrittlement and processing difficulties, increasing production and usage costs and complexity. Introducing chemical crosslinking completely destroys the thermoplasticity of TPEE, making the material unrecyclable through melt processing, which contradicts current sustainable development principles and fails to meet modern industry's requirements for material environmental friendliness and recyclability. Existing technologies struggle to achieve an effective balance between the seemingly contradictory characteristics of "high temperature resistance" and "easy recycling." Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned technical problems and provide a high-temperature resistant and recyclable TPEE membrane, its preparation method, and its application.

[0006] A high-temperature resistant and recyclable TPEE membrane, comprising the following components by weight percentage:

[0007] Thermoplastic polyester elastomer (TPEE) resin: 70-85%;

[0008] High-temperature resistant reinforced filler: 10-25%;

[0009] High thermal stability additive system: 3-8%;

[0010] Compatibilizer recovery: 1-3%.

[0011] By adopting the above technical solutions, TPEE resin serves as the matrix to provide basic properties, while high-temperature resistant reinforcing fillers form a dense physical barrier network and reinforcing skeleton in the TPEE matrix, significantly improving the film's heat distortion temperature. The high thermal stability additive system synergistically inhibits the degradation of TPEE at high temperatures through different mechanisms, improving long-term thermal aging performance. The recyclable compatibilizer can dynamically repair molecular chain breakage or filler-matrix interface damage caused by shear and thermal history, ensuring the material's performance retention rate in multiple processing cycles. Thus, the film has both significantly improved high-temperature resistance and excellent recyclability.

[0012] Preferably, the high-temperature resistant reinforcing filler is a sheet-like or fibrous inorganic filler surface-treated with a silane coupling agent or a titanate coupling agent, selected from at least one of mica powder, talc powder, boron nitride (BN) or glass flakes, with an aspect ratio ≥20 and an average particle size of 5-50 μm.

[0013] By adopting the above technical solutions, the high-temperature resistant reinforcing filler in the TPEE membrane, after surface treatment, can improve the interfacial bonding between the filler and the matrix and prevent stress concentration; the sheet-like or fibrous inorganic filler with an aspect ratio ≥20 and an average particle size of 5-50μm can form a dense physical barrier network and reinforcing skeleton in the TPEE matrix, effectively inhibiting the movement and deformation of molecular chain segments at high temperatures, thereby improving the heat resistance of the TPEE membrane while maintaining its flexibility and recyclability.

[0014] Preferably, the high thermal stability additive system includes a primary antioxidant, a secondary antioxidant, and an anti-hydrolysis agent; wherein the primary antioxidant is a hindered phenol, the secondary antioxidant is a phosphite, and the anti-hydrolysis agent is a carbodiimide compound, and the weight ratio of the three is (1.5-2.5):(1-1.5):(0.5-1).

[0015] By adopting the above technical solution, a high thermal stability additive system consisting of hindered phenolic primary antioxidant, phosphite auxiliary antioxidant, and carbodiimide anti-hydrolysis agent is added to the TPEE membrane in a specific weight ratio. This system can synergistically inhibit the degradation of TPEE at high temperatures through different mechanisms, so that the TPEE membrane retains ≥85% of its tensile strength after 500 hours of thermal aging in air at 180°C, demonstrating excellent long-term thermal stability.

[0016] Preferably, the recycled compatibilizer is a polymeric compatibilizer having epoxy or anhydride functional groups, selected from at least one of glycidyl methacrylate (GMA) grafted polymer, maleic anhydride (MAH) grafted polyolefin, or ethylene-acrylate-glycidyl methacrylate terpolymer (E-MA-GMA).

[0017] By adopting the above technical solution, the epoxy groups in the recovered compatibilizer can react with the carboxyl or hydroxyl groups at the end of the TPEE during the melting process, dynamically repairing the molecular chain breakage or filler-matrix interface damage caused by shear and thermal history. This stabilizes the performance of the TPEE membrane in multiple processing cycles, achieving a tensile strength retention rate of ≥90% relative to the initial film sample after the TPEE membrane is melted, re-granulated, and re-formed three times, ensuring the excellent recyclability of the TPEE membrane.

[0018] Preferably, the TPEE resin has a Shore hardness of 40D-55D, and its soft segment is polytetramethylene ether glycol (PTMEG) and its hard segment is polybutylene terephthalate (PBT).

[0019] By adopting the above technical solution, TPEE resin with a Shore hardness of 40D-55D, soft segment of polytetramethylene ether glycol (PTMEG) and hard segment of polybutylene terephthalate (PBT) is selected as the matrix resin. Combined with 70-85% TPEE resin, 10-25% high-temperature resistant reinforcing filler, 3-8% high thermal stability additive system and 1-3% recyclable compatibilizer, the TPEE film has significantly improved high-temperature resistance, with a heat distortion temperature (1.82MPa) ≥180℃ and a tensile strength retention rate ≥85% after 500 hours of heat aging in air at 180℃. It also has excellent recyclability. After three melting and regranulation processes and re-film formation, the tensile strength retention rate relative to the initial film sample is ≥90%.

[0020] Preferably, the thickness of the film is 0.025-0.25 mm; its heat distortion temperature (1.82 MPa) is ≥180℃; after 500 hours of heat aging in air at 180℃, the tensile strength retention rate is ≥85%; after the film is melted, re-granulated, and re-formed three times, the tensile strength retention rate relative to the initial film sample is ≥90%.

[0021] By adopting the above technical solution, the film thickness is limited to 0.025-0.25 mm, enabling the film to meet practical application requirements while possessing suitable physical properties; the heat distortion temperature (1.82 MPa) is ≥180℃, indicating that the film has good high-temperature resistance and can maintain shape stability in high-temperature environments; after 500 hours of heat aging in air at 180℃, the tensile strength retention rate is ≥85%, demonstrating that the film has excellent long-term thermal stability; after three melting, regranulation, and re-filming, the tensile strength retention rate relative to the initial film sample is ≥90%, indicating that the film has excellent recyclability and solves the technical problem of non-recyclability caused by traditional high-temperature modification.

[0022] A method for preparing a high-temperature resistant and recyclable TPEE membrane includes the following steps:

[0023] a) Surface treatment of high-temperature resistant reinforced filler;

[0024] b) Premix TPEE resin, surface-treated high-temperature resistant reinforcing filler, high thermal stability additive system and recycled compatibilizer;

[0025] c) The premixed material is melt-blended and extruded granulated at 220-250℃ using a twin-screw extruder to obtain composite masterbatch;

[0026] d) The composite masterbatch is cast into a film by a single screw extruder or blown into a film by a blown film machine, with the forming temperature controlled at 220-240℃.

[0027] By adopting the above technical solutions, surface treatment of the high-temperature resistant reinforced filler can improve the interface bonding between the filler and the matrix, prevent stress concentration, and maintain flexibility and recyclability while improving heat resistance. Premixing the components can make the material evenly distributed. Melting and blending and extruding and granulating the components through a twin-screw extruder at 220-250℃ can fully integrate the components to form a composite masterbatch. Film formation by casting with a single-screw extruder or blow molding with a blown film machine, and controlling the molding temperature at 220-240℃, can ensure the quality of film formation. Finally, a TPEE film with significantly improved high-temperature resistance (heat distortion temperature (1.82MPa) ≥180℃, tensile strength retention rate ≥85% after 500 hours of heat aging in air at 180℃) and excellent recyclability (tensile strength retention rate ≥90% after three melting and regranulation and re-film formation) is obtained.

[0028] Preferably, in step a), the surface treatment is a dry treatment, in which the filler is treated with 1-3% of its weight of silane coupling agent KH-550 or titanate coupling agent NDZ-201 in a high-speed mixer at 80-100°C for 10-15 minutes.

[0029] By adopting the above technical solution, dry surface treatment of the filler with silane coupling agent KH-550 or titanate coupling agent NDZ-201 can improve the interfacial bonding between the filler and the matrix, prevent stress concentration, and maintain flexibility and recyclability while improving the heat resistance of the TPEE membrane. Treatment at 80-100℃ for 10-15 minutes in a high-speed mixer can ensure that the coupling agent and the filler can fully interact and guarantee the treatment effect.

[0030] Preferably, in step d), after film formation, an online heat setting treatment is performed at a temperature of 150-180°C for 5-15 seconds to release internal stress and stabilize the filler orientation.

[0031] By adopting the above technical solution, the film is subjected to online heat setting treatment after film formation. The setting temperature is 150-180℃ and the time is 5-15 seconds. This can release internal stress and stabilize the orientation of fillers, thereby enabling the TPEE film to obtain more uniform and stable long-term performance, and improve the performance retention rate after aging and the recycling performance retention rate.

[0032] Application of a high-temperature resistant and recyclable TPEE film in insulating films for power batteries of new energy vehicles, high-temperature resistant cable wrapping tapes, reusable industrial high-temperature tapes, or internal heat-insulating reflective films for electronic appliances.

[0033] By adopting the above technical solution, and utilizing the high temperature resistance and recyclability of TPEE film, it can meet the dual requirements of heat resistance and environmental protection for insulating films for power batteries of new energy vehicles, high temperature resistant cable wrapping tapes, reusable industrial high temperature tapes, or internal heat insulation and reflective films for electronic appliances. This solves the technical problem that traditional high temperature resistant modification leads to non-recyclable materials.

[0034] In summary, this application includes at least one of the following beneficial technical effects:

[0035] 1. By combining TPEE resin with high-temperature resistant reinforcing filler in a specific ratio, a dense physical barrier network and reinforcing skeleton are formed in the TPEE matrix, which significantly improves the heat distortion temperature of the film, making its heat distortion temperature (1.82MPa) ≥180℃;

[0036] 2. The synergistic effect of the main antioxidant, auxiliary antioxidant, and anti-hydrolysis agent in the high thermal stability additive system inhibits the degradation of TPEE at high temperatures, ensuring that the tensile strength retention rate of the film is ≥85% after 500 hours of thermal aging in air at 180℃.

[0037] 3. Recyclable compatibilizers can repair and stabilize the interfaces and molecular chains damaged during repeated processing, so that after the film is melted, re-granulated and re-formed three times, the tensile strength of the film can be maintained at ≥90% of that of the initial film sample, which solves the problem of non-recyclability of materials caused by traditional high-temperature modification. Detailed Implementation

[0038] The high-temperature resistant and recyclable TPEE membrane provided in this application includes TPEE resin, high-temperature resistant reinforcing filler, a high-thermal-stability additive system, and a recyclable compatibilizer. TPEE resin serves as the matrix material, providing the membrane with basic physical properties. The high-temperature resistant reinforcing filler is dispersed within the TPEE resin matrix, forming a physical reinforcement network that improves the membrane's heat distortion temperature and mechanical properties. The high-thermal-stability additive system inhibits oxidation, hydrolysis, and other degradation reactions of the TPEE resin at high temperatures, ensuring the membrane's long-term thermal stability. The recyclable compatibilizer repairs and stabilizes damaged interfaces and molecular chains during multiple recycling processes, ensuring the membrane's performance retention rate. This achieves the effect of significantly improving the membrane's high-temperature resistance while maintaining its excellent recyclability. This is because TPEE resin itself has a certain performance foundation, the special structure and distribution of the high-temperature resistant reinforcing filler effectively restrict molecular chain movement, the high-thermal-stability additive system protects the molecular chains from a chemical perspective, and the recyclable compatibilizer maintains the material's performance at the microstructural level.

[0039] Specifically, the TPEE resin has a Shore hardness of 40D-55D, with its soft segment being polytetramethylene ether glycol (PTMEG) and its hard segment being polybutylene terephthalate (PBT). This structure of TPEE resin provides good flexibility and mechanical properties. The Shore hardness within this range allows the membrane to maintain appropriate hardness and elasticity in various applications. The soft segment PTMEG imparts flexibility and elasticity to the material, while the hard segment PBT provides a certain degree of rigidity and heat resistance. Alternative TPEE resins can be other thermoplastic polyester elastomers with similar structures and properties, but the ratio and properties of the soft and hard segments must be similar to this design. The TPEE resin constitutes 70-85% by weight in the membrane; this proportion ensures the dominance of the matrix material and provides a good foundation for the dispersion and bonding of other components.

[0040] Specifically, the high-temperature resistant reinforcing filler is a sheet-like or fibrous inorganic filler surface-treated with a silane coupling agent or titanate coupling agent, selected from at least one of mica powder, talc powder, boron nitride (BN), or glass flakes, with an aspect ratio ≥20 and an average particle size of 5-50 μm. Taking mica powder as an example, it is a sheet-like inorganic filler with good heat resistance and chemical stability. After surface treatment, the coupling agent on its surface can form a good interfacial bond with the TPEE resin, enhancing the interaction between the filler and the matrix. Talc powder is also a commonly used sheet-like filler, possessing lubricity and certain heat resistance, which can improve the heat resistance of the membrane while also improving its processing performance. Boron nitride (BN) has high thermal conductivity and heat resistance, effectively improving the heat dissipation performance and thermal stability of the membrane. Glass flakes have good barrier and corrosion resistance, enhancing the protective performance of the membrane. These fillers, with an aspect ratio ≥20, can form an effective barrier and reinforcing network in the TPEE matrix, inhibiting the movement and deformation of molecular chains at high temperatures. With an average particle size ranging from 5 to 50 μm, the filler is uniformly dispersed in the matrix, preventing agglomeration. Replaceable fillers can be other inorganic fillers with similar structures and properties, but they must meet requirements regarding surface treatment, aspect ratio, and particle size. The high-temperature resistant reinforcing filler constitutes 10-25% of the membrane by weight; this proportion significantly improves its high-temperature resistance without affecting the membrane's flexibility and processability.

[0041] Specifically, the high-thermal-stability additive system includes a primary antioxidant, a secondary antioxidant, and an anti-hydrolysis agent. The primary antioxidant is a hindered phenol, such as the common Irganox 1010, which can capture free radicals and prevent oxidation reactions initiated by free radicals, thereby protecting the molecular chains of TPEE resin. The secondary antioxidant is a phosphite, such as Irgafos 168, which can decompose hydroperoxides, preventing further oxidation reactions initiated by hydroperoxides, and works synergistically with the primary antioxidant to improve the antioxidant effect. The anti-hydrolysis agent is a carbodiimide compound, such as Stabaxol P400, which can inhibit the hydrolysis of ester bonds and protect the structural stability of TPEE resin under high-temperature and humid conditions. The weight ratio of the three is (1.5-2.5):(1-1.5):(0.5-1). This ratio allows the three additives to exert their optimal synergistic effect, inhibiting the degradation of TPEE at high temperatures through different mechanisms. The primary antioxidant can be other hindered phenolic compounds with similar antioxidant properties, the secondary antioxidant can be other phosphite compounds, and the anti-hydrolysis agent can be other carbodiimide compounds, but their synergistic effects and performance must be consistent with this scheme. The high thermal stability additive system accounts for 3-8% of the membrane by weight. This proportion can effectively improve the long-term thermal stability of the membrane without increasing costs too much.

[0042] Specifically, the recycled compatibilizer is a polymeric compatibilizer with epoxy or anhydride functional groups, selected from at least one of glycidyl methacrylate (GMA) grafted polymers, maleic anhydride (MAH) grafted polyolefins, or ethylene-acrylate-glycidyl methacrylate terpolymers (E-MA-GMA). Taking ethylene-acrylate-glycidyl methacrylate terpolymers (E-MA-GMA) as an example, its epoxy groups can react with the carboxyl or hydroxyl groups at the TPEE ends during melting, dynamically repairing molecular chain breakage or filler-matrix interface damage caused by shear and thermal history, thereby stabilizing the material's properties. Glycidyl methacrylate (GMA) grafted polymers and maleic anhydride (MAH) grafted polyolefins also have similar effects, improving the compatibility and performance stability of the material during multiple recycling processes. Alternative recycled compatibilizers can be other polymeric compatibilizers with similar functional groups and properties, but their compatibility and reactivity with TPEE resin and other components must be ensured. The weight percentage of the recycled compatibilizer in the membrane is 1-3%. This ratio ensures the recycling effect without affecting other membrane properties.

[0043] The membrane has a thickness of 0.025-0.25 mm, a range that meets the needs of various applications. Its heat distortion temperature (1.82 MPa) is ≥180℃, indicating good dimensional stability at high temperatures. After 500 hours of thermal aging in air at 180℃, the tensile strength retention rate is ≥85%, demonstrating excellent long-term thermal stability. After three cycles of melting, regranulation, and re-forming, the tensile strength retention rate relative to the initial film sample is ≥90%, reflecting the membrane's good recyclability.

[0044] Through unique formulation design, a TPEE resin with a specific structure is composited with surface-treated, high-temperature resistant reinforcing fillers. A high-thermal-stability additive system provides chemical protection, and a recyclable compatibilizer is introduced to achieve interface repair and performance stabilization. A stable heat-resistant structure is constructed at both the molecular chain level and the macroscopic filler reinforcement level, ensuring the material's performance retention across multiple processing cycles. Compared to traditional methods, this significantly improves the membrane's high-temperature resistance and solves the recyclability issue, providing an ideal material choice for high-end manufacturing and the circular economy.

[0045] The present invention will be described in detail below through specific embodiments and comparative examples.

[0046] I. Experimental Materials

[0047] TPEE resin: Grade H4555 (Shore hardness 55D, hard segment PBT, soft segment PTMEG).

[0048] High-temperature resistant reinforced filler:

[0049] Mica powder: average particle size 25μm, aspect ratio ~30.

[0050] Talc: average particle size 10μm, aspect ratio ~20.

[0051] Boron nitride (BN) sheets: average sheet diameter 15 μm.

[0052] High thermal stability additives:

[0053] Main antioxidant: Irganox 1010.

[0054] Co-antioxidant: Irgafos168.

[0055] Anti-hydrolysis agent: Stabaxol P400 (polycarbodiimide).

[0056] Recycled compatibilizer: AX8900 (ethylene-acrylate-glycidyl methacrylate terpolymer, E-MA-GMA).

[0057] Crosslinking agent for comparison: dicumyl peroxide (DCP).

[0058] II. Preparation Process

[0059] Surface treatment of filler: Dry mica powder, talc powder or BN at 100℃ for 2 hours. Add the dried filler and 2% of its weight of silane coupling agent KH-550 to a high-speed mixer, mix and stir at 90℃ for 12 minutes, and then cool for later use.

[0060] Premixing: Add TPEE resin, treated filler, additive system and compatibilizer to a low-speed mixer according to the formula and mix evenly.

[0061] Melt granulation: Using a twin-screw extruder, the temperature is set to 230-240℃, the screw speed is 300rpm, and vacuum exhaust is used to melt and extrude the premix, cool it with water, and granulate it to obtain composite masterbatch.

[0062] Initial film formation: The composite masterbatch is cast into a film at 235°C using a single-screw extruder, and then cooled by three rollers (upper / middle / lower roller temperatures: 30 / 40 / 30°C) to obtain a film with a thickness of approximately 0.1 mm (marked as G1).

[0063] Heat setting: Some film samples were processed on a heat setting roller at 170°C for 10 seconds.

[0064] Recycling experiment: The scraps or designated samples after the initial film formation were repeated in steps 3 and 4 to form a granulation and film formation process, resulting in the first recycled film (G2), the second recycled film (G3), and the third recycled film (G4).

[0065] III. Experimental formulation (by weight percentage)

[0066] Table 1: Composition of Formulations in Examples and Comparative Examples Components / Case Studies TPEE resin Mica powder (processed) Talc (processed) BN (processing) Irganox1010 Irgafos168 Stabaxol P400 Recycle compatibilizer AX8900 DCP (crosslinking agent) Example 1 80 15 0 0 1.5 1 0.5 2 0 Example 2 75 20 0 0 2 1.2 0.8 1 0 Example 3 82 0 13 0 1.8 1 0.7 1.5 0 Example 4 78 0 0 17 1.5 1 0.5 3 0 Example 5 77 10 0 8 2 1.5 1 2 0 Example 6 83 12 0 0 1.5 1 0.5 2 0 Example 7 79 16 0 0 2.2 1.3 1 0.5 0 Example 8 76 19 0 0 1.5 1 0.5 2 0 Example 9 81 14 0 0 1.5 1 0.5 2 0 Example 10 74 21 0 0 2.5 1.5 1 0 0 Comparative Example 1 100 0 0 0 0.3 0.2 0 0 0 Comparative Example 2 85 15 (Unprocessed) 0 0 1.5 1 0.5 0 0 Comparative Example 3 80 15 0 0 0 0 0 2 0 Comparative Example 4 94 0 0 0 1.5 1 0.5 2 1.5

[0067] Note: In Examples 6-10, heat setting was performed after film formation.

[0068] IV. Performance Testing and Results

[0069] Test methods: 1) Heat distortion temperature (HDT): ASTM D648, load 1.82 MPa. 2) Long-term thermal aging: The film samples were placed in a 180℃ oven and removed at 0h, 250h, and 500h respectively to test the tensile strength (ASTM D882) and elongation at break, and the retention rate was calculated. 3) Recyclability evaluation: The tensile strength and elongation at break of the primary film (G1) and the third recycled film (G3) were tested, and the performance retention rate was calculated. 4) Melt flow rate (MFR): ASTM D1238, 250℃ / 2.16kg, to evaluate changes in processing fluidity.

[0070] Table 2: Performance test results (based on the initial film-forming G1 sample) Case HDT (°C) Initial tensile strength (MPa) Initial elongation at break (%) Strength retention rate (%) after 500 hours of heat aging at 180℃ Elongation retention rate (%) after heat aging at 180℃ for 500 hours Example 1 192 58 320 92 88 Example 2 205 63 280 90 85 Example 3 188 55 350 91 89 Example 4 198 60 300 93 90 Example 5 201 62 290 91 86 Example 6 195 59 315 94 91 Example 7 208 65 260 88 82 Example 8 202 64 270 91 87 Example 9 194 57 310 93 90 Example 10 210 66 250 86 80 Comparative Example 1 155 42 550 62 58 Comparative Example 2 185 50 180 85 70 Comparative Example 3 190 56 300 75 68 Comparative Example 4 168 48 120 (Irreversible fracture) 95 30

[0071] Table 3: Recyclability Evaluation (Performance Retention Rate of G3 relative to G1) and Flowability Case Tensile strength retention rate (%) Elongation at break retention (%) MFR (g / 10min) of G1 MFR (g / 10min) of G3 Can it be successfully recycled and processed? Example 1 94 92 8.5 9.8 yes Example 2 92 90 6 7.2 yes Example 3 93 91 9 10.5 yes Example 4 96 94 7.5 8.5 yes Example 5 93 90 6.8 8 yes Example 6 95 93 8.8 9.5 yes Comparative Example 1 85 78 15 22.0 (Severely Degraded) Yes, but performance degrades quickly. Comparative Example 2 88 65 5.5 6 Yes, but processing is difficult. Comparative Example 3 80 72 8 12.0 (Degradation) yes Comparative Example 4 - - 0.5 (crosslinking) 0.5 No (Cannot be remelted and granulated)

[0072] Note: "-" indicates that the material could not be melted and processed during the third recycling due to cross-linking, and therefore could not be tested.

[0073] V. Data Analysis and Discussion

[0074] 1. High-temperature resistant reinforced filler and HDT enhancement:

[0075] The HDT of all embodiments was ≥188°C, significantly higher than that of pure TPEE (Comparative Example 1, 155°C). The HDT of Examples 2, 5, 7, 8, and 10 even exceeded 200°C. This is mainly attributed to the formation of a dense physical barrier network and reinforcing skeleton in the TPEE matrix by high content (≥19%) or high thermal conductivity (such as BN) of sheet filler, which effectively inhibited the movement and deformation of molecular chain segments at high temperatures.

[0076] Comparative Example 2 used an equal amount of untreated mica powder. Its HDT (185°C) was lower than that of Example 1 (192°C), and its initial elongation was extremely low (180%), with poor elongation retention after recycling (65%). This indicates that surface treatment (silane coupling) of the filler is crucial for improving the filler-matrix interface bonding, preventing stress concentration, and maintaining flexibility and recyclability while improving heat resistance.

[0077] 2. High thermal stability additive system and long-term thermal aging performance:

[0078] After aging at 180°C for 500 hours, all embodiments exhibited a strength retention rate of ≥88%, demonstrating excellent long-term thermal stability. This is attributed to the synergistic effect of the composite additive system: Irganox1010 captures free radicals, Irgafos168 decomposes hydrogen peroxides, and StabaxolP400 inhibits ester bond hydrolysis.

[0079] Comparative Example 3 did not contain any stabilizers. Although its initial HDT was not low (190°C), it had the lowest performance retention rate after long-term heat aging (75% strength, 68% elongation), demonstrating that physical reinforcement can improve instantaneous heat resistance, but the lack of chemical protection cannot resist long-term thermo-oxidative / hydrolytic degradation, which is often the main cause of failure in practical applications.

[0080] 3. Achieving compatibilizer recovery and recyclability:

[0081] All embodiments exhibited tensile strength retention of ≥92% and elongation retention of ≥90% after three recycling cycles, with mild changes in melt flow rate (MFR), indicating good recyclability of the material. The epoxy groups in the recovered compatibilizer (AX8900) can react with the carboxyl or hydroxyl groups at the TPEE end during melting, dynamically repairing molecular chain breakage or filler-matrix interface damage caused by shear and thermal history, thereby stabilizing performance.

[0082] Although Comparative Example 1 (pure TPEE) is recyclable, it suffers from significant thermal degradation during recycling due to the lack of a stable system and enhanced network (the MFR of G3 surged from 15 to 22), resulting in low performance retention.

[0083] Comparative Example 4 (with the addition of crosslinking agent DCP) is a complete counterexample. Although crosslinking slightly improves HDT, it severely impairs the elongation at break. Most importantly, it causes the material to lose its thermoplasticity, making it impossible to melt and recycle, which violates the core objective of this invention.

[0084] 4. Additional benefits of heat setting process (Example 6 vs. Example 1):

[0085] Example 6 (formulation same as Example 1, but heat-set) showed slightly better performance retention and recyclability retention after aging than Example 1 without heat setting. Heat setting helps eliminate processing stress, making the orientation of the sheet filler more stable, thereby obtaining more uniform and stable long-term performance.

[0086] 5. The Art of Formula Balance:

[0087] Examples 7 and 10 demonstrate high HDT peaks (208°C, 210°C) and high initial strength resulting from high filler content, but with relatively low elongation at break and slightly lower elongation retention after aging / recycling. This suggests the need to strike a balance between pursuing extreme heat resistance and maintaining overall performance (especially flexibility and recyclability).

[0088] Examples 1, 4, 6, and 9 demonstrate a better balance: HDT at 190-198℃ exhibits excellent retention rates (all >90%), resulting in optimal overall performance.

[0089] in conclusion

[0090] This invention utilizes a surface-treated, high-aspect-ratio, sheet-like heat-resistant filler to construct a physical reinforcement network, employs a composite high-efficiency heat stabilizer system to provide chemical protection, and introduces a multifunctional recyclable compatibilizer to achieve interface repair and performance stabilization. This synergistic process produces a TPEE film with significantly improved high-temperature resistance (HDT ≥ 180℃, high long-term thermal aging performance retention) and excellent recyclability (performance retention ≥ 90% after three recycling cycles). This technical solution creatively solves the industry problem of loss of processability and recyclability often associated with high-temperature modification, providing an ideal material choice for high-end manufacturing and the circular economy.

[0091] Regarding preparation:

[0092] This application also provides a method for preparing a high-temperature resistant and recyclable TPEE membrane, comprising the following steps:

[0093] S1. Surface treatment of high-temperature resistant reinforced fillers. A dry treatment method is used, where the filler is treated with 1-3% by weight of silane coupling agent KH-550 or titanate coupling agent NDZ-201 in a high-speed mixer at 80-100℃ for 10-15 minutes. During this process, the high-speed mixer provides strong agitation, allowing the coupling agent to adhere evenly to the filler surface. Temperature control at 80-100℃ promotes the chemical reaction between the coupling agent and the filler surface, forming stable chemical bonds. The treatment time of 10-15 minutes ensures sufficient reaction and coating of the filler by the coupling agent. The high-speed mixer used provides sufficient agitation intensity and mixing effect.

[0094] S2 involves premixing TPEE resin, surface-treated high-temperature resistant reinforcing filler, a high-thermal-stability additive system, and a recycled compatibilizer. The components are then added to a low-speed mixer according to the formulation ratio. The low-speed mixer agitates the components at a slower speed to ensure initial homogeneity. This avoids filler agglomeration and uneven additive dispersion that can occur with high-speed mixing. The low-speed mixer used ensures a gentle mixing process.

[0095] S3 involves melting and blending the premixed material using a twin-screw extruder at 220-250℃, then extruding and granulating it to obtain composite masterbatch. The twin-screw extruder possesses excellent mixing and plasticizing capabilities. At 220-250℃, TPEE resin and other components can fully melt, resulting in thorough interaction between the components. The rotation and shearing action of the screw ensures uniform mixing of the material, ultimately extruding it into strips. After water cooling and pelletizing, the composite masterbatch is obtained. The equipment used is a twin-screw extruder, and temperature control is a crucial factor; a suitable temperature ensures good material flowability and mixing effect.

[0096] S4 involves casting the composite masterbatch into a film using a single-screw extruder or blown film forming machine, with the forming temperature controlled at 220-240℃. Single-screw extruder casting involves heating and melting the composite masterbatch, extruding it through a die into a thin film, and then cooling it with cooling rollers. Blown film forming involves extruding molten composite masterbatch through a ring die to form a tubular film, then expanding it with air and cooling it to form the final film. Controlling the forming temperature at 220-240℃ ensures good film quality and performance. The equipment used is either a single-screw extruder or a blown film forming machine; the appropriate film forming method is selected based on different production needs and product requirements.

[0097] S5, after film formation, undergoes online heat setting at 150-180℃ for 5-15 seconds to release internal stress and stabilize filler orientation. Heat setting allows the film to be held at a specific temperature for a period of time, eliminating internal stress generated during processing and making the orientation of the sheet filler more stable. This helps improve the dimensional stability and long-term performance of the film. The equipment used is a heat setting roller, and the heat setting effect is achieved by controlling the temperature and time.

[0098] The implementation principle of this embodiment is as follows: This method, through precise control of each step, including the surface treatment of the filler, premixing of each component, melt granulation, film formation, and heat setting, ensures that the components fully exert their synergistic effect. At the microscopic level, it guarantees good bonding between the filler and the matrix, effective dispersion of additives, and stability of the molecular chains; at the macroscopic level, it produces a TPEE membrane with excellent high-temperature resistance and recyclability. Compared with traditional preparation methods, this method combines material formulation and process characteristics, achieving a balance between high performance and high recyclability, providing an innovative technical solution for the preparation of TPEE membranes.

[0099] In other embodiments: different processes were used for the surface treatment of the high-temperature resistant reinforcing filler when preparing the TPEE membrane. Here, a wet treatment was used, in which the filler was dispersed in a solution containing silane coupling agent KH-550 or titanate coupling agent NDZ-201, and treated under specific temperature and stirring conditions. This treatment method allows the coupling agent to be more uniformly coated on the filler surface, further improving the interfacial bonding between the filler and the TPEE resin. The filler treated by the wet process can be better dispersed in the TPEE matrix, forming a more complete reinforcing network, which may further improve the high-temperature resistance and mechanical properties of the membrane.

[0100] The principle is as follows: by modifying the surface treatment process of the high-temperature resistant reinforced filler, the coupling agent is more fully integrated with the filler, enhancing the interaction between the filler and the matrix. This helps improve the overall performance of the material, especially in terms of high-temperature resistance and recyclability. Compared with traditional methods, it provides a new preparation approach and technical route that can better meet the performance requirements of different application scenarios.

[0101] About the application:

[0102] This application also provides an application of a high-temperature resistant and recyclable TPEE membrane, which is used as an insulating film for power batteries in new energy vehicles. In new energy vehicles, the power battery is a core component, generating heat during operation, requiring the insulating material to possess excellent high-temperature resistance and insulation properties. This TPEE membrane has a heat distortion temperature (1.82 MPa) ≥180℃, maintaining stable dimensions and performance under high-temperature environments, effectively preventing leakage between batteries. Furthermore, after 500 hours of heat aging in air at 180℃, its tensile strength retention rate is ≥85%, ensuring reliability during long-term use. Moreover, this membrane has good recyclability, meeting current environmental protection and sustainable development requirements. After the battery's lifespan ends, the TPEE membrane can be melted and recycled to produce usable membrane materials again, reducing resource waste and environmental pollution.

[0103] The implementation principle of this embodiment is as follows: Utilizing the high-temperature resistance and recyclability of the TPEE membrane, it meets the special insulation requirements of power batteries for new energy vehicles. Under high-temperature environments, the membrane's stability ensures the safe operation of the battery system; its recyclability aligns with the trends of environmental protection and sustainable economic development. Compared to traditional insulating materials, this TPEE membrane has significant advantages in performance and environmental friendliness, providing a more ideal insulating material choice for the new energy vehicle industry.

[0104] This application also provides an application of a high-temperature resistant and recyclable TPEE film, which is used as a heat-insulating and reflective film inside electronic and electrical appliances. In electronic and electrical equipment, heat is generated during operation, and excessively high temperatures can affect the performance and lifespan of the equipment. The high thermal stability and excellent barrier properties of this TPEE film effectively block heat transfer, thus providing heat insulation. Simultaneously, the surface of the film can be specially treated to reflect heat, further improving the heat insulation effect. After 500 hours of heat aging in air at 180°C, its tensile strength retention rate is ≥85%, ensuring the structural stability of the film and that its heat-insulating and reflective performance remains unaffected during long-term use. Furthermore, the recyclability of this film allows for the recycling and reuse of the film material when electronic and electrical equipment is upgraded, reducing production costs and resource consumption.

[0105] The implementation principle of this embodiment is as follows: Utilizing the high-temperature resistance and heat-insulating reflective properties of TPEE film, the internal heat insulation requirements of electronic and electrical equipment are met. Through the heat insulation and reflection effects of the film, the internal temperature of the equipment is reduced, improving its performance and reliability. Its recyclability meets the requirements of modern industry for environmental protection and resource recycling. Compared with traditional heat-insulating reflective materials, this TPEE film has significant advantages in performance and sustainability, providing a superior material solution for the electronics and electrical industry.

[0106] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A high-temperature resistant and recyclable TPEE membrane, characterized in that, By weight percentage, it includes the following components: Thermoplastic polyester elastomer (TPEE) resin: 70-85%; High-temperature resistant reinforced filler: 10-25%; High thermal stability additive system: 3-8%; Compatibilizer recovery: 1-3%.

2. The TPEE membrane according to claim 1, characterized in that, The high-temperature resistant reinforcing filler is a sheet-like or fibrous inorganic filler that has been surface-treated with a silane coupling agent or a titanate coupling agent. It is selected from at least one of mica powder, talc powder, boron nitride (BN) or glass flakes, with an aspect ratio ≥20 and an average particle size of 5-50 μm.

3. The TPEE membrane according to claim 1, characterized in that, The high thermal stability additive system includes a primary antioxidant, a secondary antioxidant, and an anti-hydrolysis agent; wherein the primary antioxidant is a hindered phenol, the secondary antioxidant is a phosphite, and the anti-hydrolysis agent is a carbodiimide compound, and the weight ratio of the three is (1.5-2.5):(1-1.5):(0.5-1).

4. The TPEE membrane according to claim 1, characterized in that, The recycled compatibilizer is a polymeric compatibilizer having epoxy or anhydride functional groups, selected from at least one of glycidyl methacrylate (GMA) grafted polymer, maleic anhydride (MAH) grafted polyolefin, or ethylene-acrylate-glycidyl methacrylate terpolymer (E-MA-GMA).

5. The TPEE membrane according to claim 1, characterized in that, The TPEE resin has a Shore hardness of 40D-55D, with its soft segment being polytetramethylene ether glycol (PTMEG) and its hard segment being polybutylene terephthalate (PBT).

6. The TPEE membrane according to claim 1, characterized in that, The film has a thickness of 0.025-0.25 mm; its heat distortion temperature (1.82 MPa) is ≥180℃; after 500 hours of heat aging in air at 180℃, the tensile strength retention rate is ≥85%; after the film is melted, re-granulated, and re-formed three times, the tensile strength retention rate relative to the initial film sample is ≥90%.

7. A method for preparing a high-temperature resistant and recyclable TPEE membrane as described in any one of claims 1-6, characterized in that, Includes the following steps: a) Surface treatment of high-temperature resistant reinforced filler; b) Premix TPEE resin, surface-treated high-temperature resistant reinforcing filler, high thermal stability additive system and recycled compatibilizer; c) The premixed material is melt-blended and extruded granulated at 220-250℃ using a twin-screw extruder to obtain composite masterbatch; d) The composite masterbatch is cast into a film by a single screw extruder or blown into a film by a blown film machine, with the forming temperature controlled at 220-240℃.

8. The preparation method according to claim 7, characterized in that, In step a), the surface treatment is a dry treatment, in which the filler is treated with 1-3% of its weight of silane coupling agent KH-550 or titanate coupling agent NDZ-201 in a high-speed mixer at 80-100°C for 10-15 minutes.

9. The preparation method according to claim 7, characterized in that, In step d), after film formation, an online heat setting treatment is performed at a temperature of 150-180℃ for 5-15 seconds to release internal stress and stabilize the filler orientation.

10. The application of a high-temperature resistant and recyclable TPEE film as described in any one of claims 1-6 in insulating films for power batteries of new energy vehicles, high-temperature resistant cable wrapping tapes, reusable industrial high-temperature tapes, or internal heat-insulating reflective films for electronic appliances.