Multilayer structure TPEE light shielding material and preparation method

Abstract

The present application relates to the technical field of polyester material, in particular to a multilayer structure TPEE light shielding material and a preparation method. The present application overcomes the problem that the mechanical properties and aging resistance of TPEE light shielding material cannot be considered simultaneously. The reinforcing layer is prepared by hot pressing molding of PET, modified alumina, silane modified aluminum borate whisker and maleic anhydride grafted polyethylene; the light shielding layer is prepared by hot pressing molding of TPEE, composite light shielding agent, maleic anhydride grafted POE, nano silicon dioxide and ultraviolet absorber; the aging resistant layer is prepared by casting film of TPEE, polytetrafluoroethylene powder, light stabilizer, ultraviolet absorber and antioxidant; the reinforcing layer, the light shielding layer and the aging resistant layer are stacked in sequence, and the multilayer structure TPEE light shielding material is obtained by composite hot pressing molding, which significantly improves the mechanical properties of TPEE light shielding material and effectively inhibits photo-oxidative degradation and thermal oxidative degradation.

Description

Technical Field

[0001] This invention relates to the field of polyester materials technology, specifically to a multilayer TPEE light-shielding material and its preparation method. Background Technology

[0002] With the increasing demand for high-performance light-blocking materials in modern industry and daily life, thermoplastic polyester elastomers (TPEE) are widely used in light-blocking products in the automotive, construction, electronics, and medical fields due to their excellent elasticity, strength, chemical resistance, and processing performance. Traditional light-blocking materials, such as PVC, rubber, or ordinary plastic films, often have many limitations. For example, PVC materials may contain plasticizers, posing potential risks to the environment and human health; rubber materials are prone to aging and hardening during long-term use and are complex to process; ordinary plastic films have insufficient mechanical properties and weather resistance, making it difficult to meet the requirements of high strength and long service life.

[0003] Currently, TPEE-based light-blocking materials are used in the market, but existing technologies still face significant challenges. On the one hand, to achieve good light-blocking effects, a large amount of colorant or other light-blocking components is usually filled into the TPEE matrix, which to some extent sacrifices the material's original mechanical properties, such as tensile strength, tear strength, and fatigue resistance. In scenarios requiring repeated bending, stretching, or impact, these materials are prone to cracking, deformation, or failure, thus shortening the product's lifespan. On the other hand, the aging resistance of existing TPEE light-blocking materials is generally unsatisfactory, especially when exposed to harsh environments such as ultraviolet radiation, high temperatures, and oxygen for extended periods. These materials are highly susceptible to oxidative degradation, yellowing, loss of gloss, and surface cracking. These aging phenomena not only severely affect the material's light-blocking function and aesthetics but also significantly reduce product reliability and safety. Furthermore, the ester bonds in the TPEE molecular chain structure are easily broken under hydrolysis, thermal oxidation, and photo-oxidation, leading to performance degradation. Therefore, how to effectively improve the comprehensive mechanical properties and aging resistance of TPEE light-blocking materials is a key technical problem that urgently needs to be solved.

[0004] To address this, a multilayer TPEE light-shielding material and its preparation method are proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a multilayer TPEE light-shielding material and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] It should be noted that all parts in this invention are parts by weight.

[0008] This invention provides a method for preparing a multilayer TPEE light-shielding material, the method of which is as follows:

[0009] A reinforcing layer is obtained by hot pressing a mixture of PET, modified alumina, and silane-modified aluminum borate whiskers; a light-shielding layer is obtained by hot pressing a mixture of TPEE, composite light-shielding agent, maleic anhydride-grafted POE, nano-silica, and UV absorber I; an aging-resistant layer is obtained by casting a mixture of TPEE, polytetrafluoroethylene powder, light stabilizer, UV absorber II, and antioxidant; and a multi-layer TPEE light-shielding material is obtained by hot pressing a composite of the reinforcing layer, light-shielding layer, and aging-resistant layer.

[0010] Modified alumina was obtained by spray coating α-Al2O3 powder with silane coupling agent KH550 solution;

[0011] The composite opacifier is obtained by mixing rutile TiO2 and zirconium oxide.

[0012] Preferably, the method for preparing the reinforcing layer is as follows: 65 parts of PET (intrinsic viscosity 0.8 dL / g), 10-15 parts of modified alumina, 8-12 parts of silane-modified aluminum borate whiskers, 6 parts of maleic anhydride-grafted polyethylene, and 0.8 parts of antioxidant 1010 are added to a high-speed mixer and mixed at 800 rpm for 5 min. The mixture is then added to a twin-screw extruder, water-cooled and pelletized, and vacuum-dried at 80℃ for 2 h to obtain the reinforcing material. The reinforcing material is then pressed through a hot press at 260-280℃ and 10 MPa to obtain a reinforcing layer with a thickness of 2-3 mm. The twin-screw temperature is 250℃ (feeding) → 275℃ (melting) → 265℃ (die), and the screw speed is 160 rpm.

[0013] Preferably, the method for preparing the light-shielding layer is as follows: 70-80 parts of TPEE are added to a mixer and treated at 170°C for 5 minutes. Then, 15-20 parts of composite light-shielding agent and 5 parts of maleic anhydride-grafted POE are added. The mixture is heated to 185°C and stirred for 5 minutes at a speed of 60 rpm. Then, 3 parts of nano-silica and 0.8-1.8 parts of ultraviolet absorber (UV-326 and UV-1577 are mixed at a mass ratio of 1:1) are added. The mixture is cooled to 170°C and stirred for 3 minutes. After discharge, the mixture is hot-pressed at 180°C to obtain a light-shielding layer with a thickness of 1 mm.

[0014] Preferably, the aging-resistant layer is prepared as follows: 45 parts TPEE, 6 parts polytetrafluoroethylene powder, 1-1.5 parts light stabilizer HALS 770, 1.5-2.5 parts ultraviolet absorber UV 327, 0.75-1.25 parts antioxidant 1010 and 0.6 parts acrylate leveling agent (item number PB42512) are added to DMF (solid content 30%), ball-milled and dispersed for 2 hours, cast into a film on release paper and subjected to step drying at 80℃×20min→100℃×10min→120℃×5min, with a casting speed of 5-8m / min; the aging-resistant layer with a thickness of 100±5μm is obtained by peeling.

[0015] Preferably, the modified alumina is prepared as follows: 20 parts of α-Al2O3 powder with an average particle size of 1μm are vacuum dried at 120℃ for 2h, cooled to 60℃, and then spray-coated with 30 parts of 2wt% silane coupling agent KH550 solution (solvent is ethanol). Then, it is thermally cured at 130℃ for 0.5-1.5h to obtain modified alumina.

[0016] Preferably, the preparation method of silane-modified aluminum borate whiskers is as follows: 20 parts of aluminum borate whiskers (diameter 0.5 μm, aspect ratio 30:1) are added to 40 parts of 5 wt% KH570 ethanol solution, ultrasonically dispersed at 40 kHz for 30 min, and heat-treated and cured at 120℃ for 1.5-2.5 h to obtain silane-modified aluminum borate whiskers.

[0017] Preferably, the composite light-blocking agent is prepared as follows: Rutile TiO2 (200nm, CAS 1317-80-2) and zirconium oxide are mixed at a mass ratio of 4-8:4, ball-milled at 250rpm for 2h, 0.5wt% aluminate coupling agent DL-411 is added, the temperature is raised to 80℃, stirred at 1200rpm for 30min, and passed through an 800-mesh sieve to obtain the composite light-blocking agent.

[0018] Preferably, the composite hot pressing molding process is as follows: the reinforcing layer, the light-shielding layer and the aging-resistant layer are stacked in sequence and added to the hot pressing composite machine. The composite temperature is 180-190℃, the composite pressure is 8-10MPa, the holding time is 5min, and after the holding time is completed, the temperature is reduced to below 60℃. After demolding, a multi-layer TPEE light-shielding material is obtained.

[0019] In another aspect, the present invention provides a multi-layer TPEE light-shielding material, which is prepared by any of the above-mentioned preparation methods; the multi-layer TPEE light-shielding material consists of a reinforcing layer, a light-shielding layer and an aging-resistant layer from the inside out.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. The reinforcing layer of this application uses PET as the substrate, and is compounded with modified alumina and silane-modified aluminum borate whiskers. The interfacial bonding state is optimized by grafting polyethylene with maleic anhydride as a compatibilizer, and antioxidants are introduced to ensure the stability of the components during processing and use. PET itself has high modulus characteristics, modified alumina can fill the micro-voids inside the substrate and disperse stress, and silane-modified aluminum borate whiskers, with their special whisker structure, form a "skeleton support" when the material is subjected to external forces, effectively hindering crack propagation. The three, together with the compatibilizer, work synergistically, combined with the thorough mixing of twin-screw extrusion and the dense molding of flat vulcanization, to form a stable mechanical reinforcement system in the reinforcing layer, thereby improving the mechanical properties of the entire multilayer material.

[0022] 2. The light-shielding layer of this invention not only achieves excellent visible light blocking effect through composite light-shielding agents, but also combines the reinforcing effect of nano-silica and the toughening modification of maleic anhydride-grafted POE. Nano-silica can fill the microscopic defects of the TPEE matrix, enhance the structural density of the material, and improve its resistance to deformation; maleic anhydride-grafted POE optimizes the toughness and processing performance of the material, enabling the light-shielding layer to maintain good mechanical stability while possessing excellent light-shielding effect, avoiding the sacrifice of material mechanical properties in the pursuit of light-shielding effect alone; in addition, the ultraviolet absorber in the layer effectively absorbs ultraviolet rays, preventing photoaging from damaging the mechanical properties of the material.

[0023] 3. The aging-resistant layer of this application constructs a dual aging-resistant system of "active protection + physical barrier" through multi-component synergy, significantly improving the material's weather resistance. Based on the TPEE matrix, polytetrafluoroethylene powder is uniformly dispersed to form a dense physical barrier, effectively blocking the intrusion of aging factors such as oxygen and moisture, reducing the corrosive effects of the external environment on the material's interior. The light stabilizer HALS 770 captures free radicals generated during aging, terminating free radical chain reactions and delaying the degradation of TPEE molecular chains. The ultraviolet absorber UV 327 preferentially absorbs ultraviolet light, preventing direct damage to the matrix structure from ultraviolet rays. The antioxidant 1010 removes peroxides generated by thermal oxidation, blocking the thermal-oxidative aging path. Furthermore, the acrylate leveling agent ensures film uniformity, preventing aging weak points caused by film defects. The synergistic effect of all components comprehensively resists aging caused by factors such as ultraviolet rays, heat, and humidity, extending the material's service life.

[0024] 4. This application modifies the surface of alumina and aluminum borate whiskers in the reinforcing layer with silane coupling agent. This modification improves the dispersion uniformity of inorganic fillers in the PET polymer matrix and significantly enhances the interfacial bonding strength between the fillers and the polymer. By strengthening the interfacial bond, external stress can be transferred more efficiently from the polymer matrix to the high modulus filler, thereby synergistically improving the overall tensile strength and tear strength of the material, making the macroscopic mechanical performance of the composite material far superior to that of the unmodified filler system.

[0025] 5. The gradient structure of this application, consisting of a "reinforcing layer - light-shielding layer - aging-resistant layer," features complementary and synergistic functions among its layers. The inner reinforcing layer provides the primary mechanical support, offering a stable structural foundation for the material. The middle light-shielding layer, while blocking light, enhances overall mechanical stability through component design. The outer aging-resistant layer directly resists external aging factors, protecting the two inner layers from corrosion. This structural design allows each layer to fully leverage its advantages, avoiding the shortcomings of a single-layer structure in terms of mechanical or aging resistance. The aging-resistant layer, by blocking ultraviolet rays, reduces the aging damage caused by ultraviolet radiation to the PET in the reinforcing layer and the TPEE in the light-shielding layer, ensuring the long-term stability of the reinforcing layer's mechanical properties. Furthermore, the mechanical support of the reinforcing layer provides structural protection for the aging-resistant and light-shielding layers, preventing surface damage due to substrate deformation, thus achieving dual protection of mechanical and aging resistance properties. Attached Figure Description

[0026] Figure 1 The figures show the mechanical property test results of Examples 1-3 and Comparative Examples 1-5 of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Please see Figure 1 This invention provides a multilayer TPEE light-shielding material and its preparation method, the technical solution of which is as follows:

[0029] Example 1

[0030] Twenty parts of α-Al₂O₃ powder with an average particle size of 1 μm were vacuum dried at 120 °C for 2 h. After cooling to 60 °C, the powder was spray-coated with 30 parts of a 2 wt% silane coupling agent KH550 solution (ethanol as solvent), followed by heat curing at 130 °C for 0.5 h to obtain modified alumina. Twenty parts of aluminum borate whiskers (0.5 μm in diameter, aspect ratio 30:1) were added to 40 parts of a 5 wt% KH570 ethanol solution, ultrasonically dispersed at 40 kHz for 30 min, and then heat-cured at 120 °C for 1.5 h to obtain silane-modified aluminum borate whiskers. 65 parts of PET (intrinsic viscosity 0.8 dL / g), 10 parts of modified alumina, 8 parts of silane-modified aluminum borate whiskers, 6 parts of maleic anhydride-grafted polyethylene, and 0.8 parts of antioxidant 1010 were added to a high-speed mixer and mixed at 800 rpm for 5 minutes. The mixture was then fed into a twin-screw extruder, water-cooled and pelletized, and vacuum-dried at 80℃ for 2 hours to obtain the reinforced material. The reinforced material was then pressed in a hot press at 260℃ and 10 MPa to obtain a reinforced layer with a thickness of 2-3 mm. The twin-screw temperature was 250℃ (feeding) → 275℃ (melting) → 265℃ (die), and the screw speed was 160 rpm.

[0031] Rutile TiO2 (200 nm) and zirconium oxide were mixed at a mass ratio of 4:4 and ball-milled at 250 rpm for 2 hours. 0.5 wt% aluminate coupling agent (DL-411) was added, and the mixture was heated to 80°C and stirred at 1200 rpm for 30 minutes. The mixture was then passed through an 800-mesh sieve to obtain a composite light-blocking agent. 70 parts of TPEE were added to a mixer and treated at 170°C for 5 minutes. 15 parts of the composite light-blocking agent and 5 parts of maleic anhydride-grafted POE were added, and the mixture was heated to 185°C and stirred for 5 minutes at 60 rpm. 3 parts of nano-silica and 0.8 parts of UV absorber (UV-326 and UV-1577 mixed at a mass ratio of 1:1) were added. The mixture was cooled to 170°C and stirred for 3 minutes. After discharge, the mixture was hot-pressed at 180°C to obtain a light-blocking layer with a thickness of 1 mm.

[0032] 45 parts TPEE, 6 parts polytetrafluoroethylene powder, 1 part light stabilizer HALS 770, 1.5 parts UV absorber UV327, 0.75 parts antioxidant 1010 and 0.6 parts acrylate leveling agent were added to DMF (solid content 30%), ball-milled and dispersed for 2 hours, cast into a film on release paper and subjected to step drying at 80℃×20min→100℃×10min→120℃×5min, with a casting speed of 5m / min; the aging-resistant layer with a thickness of 100±5μm was obtained by peeling.

[0033] The reinforcing layer, the light-shielding layer, and the aging-resistant layer are stacked in sequence and placed in a hot press laminating machine. The lamination temperature is 180℃, the lamination pressure is 8MPa, and the holding time is 5min. After the holding time is completed, the temperature is lowered to below 60℃. After demolding, a multi-layer TPEE light-shielding material is obtained.

[0034] Example 2

[0035] The preparation method and parameters of Example 1 are the same, except that the heat curing time for preparing modified alumina is 1 hour; the heat treatment curing time for preparing silane-modified aluminum borate whiskers is 2 hours; and the amount of modified alumina used in preparing the reinforcing layer is 12 parts, the amount of silane-modified aluminum borate whiskers is 10 parts, and the hot pressing temperature is 270°C.

[0036] Example 3

[0037] The preparation method and parameters of Example 1 are the same, except that the heat curing time for preparing modified alumina is 1.5 h; the heat treatment curing time for preparing silane-modified aluminum borate whiskers is 2.5 h; and the amount of modified alumina used for preparing the reinforcing layer is 15 parts, the amount of silane-modified aluminum borate whiskers is 12 parts, and the hot pressing temperature is 280°C.

[0038] Comparative Example 1

[0039] The preparation method and parameters of Example 1 were used, except that the alumina was not modified.

[0040] Comparative Example 2

[0041] The preparation method and parameters are the same as in Example 1, except that no modified alumina is added to the reinforcing layer.

[0042] Comparative Example 3

[0043] The preparation method and parameters of Example 1 were used, except that the aluminum borate whiskers were not modified.

[0044] Comparative Example 4

[0045] The preparation method and parameters of Example 1 are the same, except that aluminum borate whiskers were not added to the reinforcing layer.

[0046] Comparative Example 5

[0047] The preparation method and parameters of Example 1 are the same, except that maleic anhydride-grafted polyethylene is not added to the reinforcing layer.

[0048] Experiment Example 1 Mechanical Property Testing

[0049] Tensile strength was tested according to GB / T1040.3-2006 standard; the results are shown in Table 1 and... Figure 1 As shown.

[0050] Table 1 Mechanical property tests of Examples 1-3 and Comparative Examples 1-5

[0051]

[0052]

[0053] From Table 1 and Figure 1 As can be seen, in Examples 1-3, the reinforcing layer uses PET as the substrate, compounded with modified alumina and silane-modified aluminum borate whiskers. Maleic anhydride grafted onto polyethylene optimizes the interfacial bonding, while antioxidants are introduced to ensure component stability during processing and use. PET itself possesses high modulus characteristics, modified alumina fills microscopic voids within the substrate and disperses stress, while silane-modified aluminum borate whiskers, with their unique whisker structure, form a skeletal support when the material is subjected to external forces, effectively hindering crack propagation. The three components, along with a compatibilizer, work synergistically, combined with thorough mixing through twin-screw extrusion and dense molding through flat vulcanization, to form a stable mechanical reinforcement system in the reinforcing layer, thereby improving the mechanical properties of the entire multilayer material. The resulting material has a tensile strength of up to 29.3 MPa. In Comparative Example 1, no alumina modification was performed, and the α-Al₂O₃ powder surface exhibited strong polarity, while PET is a non-polar polymer. The two have poor compatibility, and the powder easily agglomerates within the matrix, failing to effectively transfer stress and even becoming stress concentration points. Modified alumina is a key rigid filler reinforcement in the reinforcing layer. Its micron-sized particles can enhance the matrix's resistance to deformation through "dispersion strengthening." In Comparative Example 2, without modified alumina, the reinforcing layer relied solely on aluminum borate whiskers, resulting in a significant decrease in overall tensile strength. In Comparative Example 3, without modification of the aluminum borate whiskers, the whiskers easily peeled off from the matrix interface, failing to perform "fibrous stress transfer" and only providing a weak filling effect, leading to a decrease in tensile strength. Aluminum borate whiskers, due to their high strength and whisker structure, form a skeletal support when the material is subjected to external forces, effectively hindering crack propagation. In Comparative Example 4, without the addition of aluminum borate whiskers, the tensile strength of the material decreased. In Comparative Example 5, without the addition of maleic anhydride-grafted polyethylene, the interfacial compatibility between components deteriorated, interfacial adhesion weakened, and stress transfer efficiency was low.

[0054] Examples 4-5

[0055] The preparation method and parameters of Example 2 are as follows, with specific differences shown in Table 2; the mass ratio of the two in Table 2 is the mass ratio of rutile TiO2 and zirconium oxide; the amount of TPEE is the amount used when preparing the light-shielding layer.

[0056] Comparative Example 6

[0057] The preparation method and parameters of Example 2 are the same, except that only rutile TiO2 is used as a light-blocking agent, and the amount is 15 parts.

[0058] Comparative Example 7

[0059] The preparation method and parameters of Example 2 are the same, except that rutile TiO2 and zirconium oxide are directly mixed in a mass ratio of 4:4 to obtain a composite opacifier.

[0060] Comparative Example 8

[0061] The preparation method and parameters of Example 2 are the same, except that maleic anhydride grafted POE was not added when preparing the light-shielding layer.

[0062] Comparative Example 9

[0063] The preparation method and parameters of Example 2 are the same, except that no nano-silica is added when preparing the light-shielding layer.

[0064] Comparative Example 10

[0065] The preparation method and parameters of Example 2 are the same, except that no ultraviolet absorber is added when preparing the light-shielding layer.

[0066] Comparative Example 11

[0067] The preparation method and parameters of Example 2 are the same, except that the light-shielding layer is not prepared by adding the materials in stages. Instead, TPEE, composite light-shielding agent, maleic anhydride grafted POE, nano silica and ultraviolet absorber are added to the internal mixer at the same time and treated at 185°C for 13 min.

[0068] Comparative Example 12

[0069] The preparation method and parameters of Example 2 are the same, except that when preparing the multilayer TPEE light-shielding material, the outermost layer is the light-shielding layer, the middle layer is the reinforcing layer, and the inner layer is the aging-resistant layer.

[0070] Experiment Example 2: Mechanical Properties and Aging Resistance Tests

[0071] The elongation at break was tested according to GB / T1040.1-2018; the aging resistance was tested according to GB / T16422.1-2019; the results are shown in Table 2.

[0072] Table 2 shows the mechanical properties and aging resistance tests of Examples 2, 4-5, and Comparative Examples 6-12.

[0073]

[0074] As shown in Table 2, in Examples 2 and 4-5, nano-silica can fill the microscopic defects of the TPEE matrix, enhance the structural density of the material, and improve its resistance to deformation. Maleic anhydride-grafted POE optimizes the toughness and processing performance of the material, enabling the light-shielding layer to maintain good mechanical stability while possessing excellent light-shielding effect, avoiding the sacrifice of material mechanical properties due to the sole pursuit of light-shielding effect. In addition, the ultraviolet absorber in the layer effectively absorbs ultraviolet light, preventing photoaging damage to the mechanical properties of the material. The resulting material has an elongation at break of up to 238%, and an elongation at break retention rate of up to 95.2%. In Comparative Example 6, only rutile TiO2 was used as a light-shielding agent. When used alone, rutile TiO2 is prone to agglomeration, which disrupts the continuity of the TPEE matrix, and lacks the synergistic dispersing effect of zirconium oxide, resulting in a decrease in material toughness. Furthermore, the absence of zirconium oxide weakens the material's ability to scatter ultraviolet light, while the photocatalytic activity of TiO2 is enhanced, accelerating TPEE degradation. In Comparative Example 7, rutile TiO2 and zirconium oxide were directly mixed at a mass ratio of 4:4 to obtain a composite light-shielding agent without the addition of aluminate coupling agent DL-411. The poor interfacial compatibility between the light-shielding agent and TPEE led to stress concentration points and decreased toughness. Uneven dispersion of the light-shielding agent resulted in weak local UV protection, while interfacial defects accelerated the intrusion of aging media. In Comparative Example 8, maleic anhydride-grafted POE was not added during the preparation of the light-shielding layer. The interfacial bonding force between the light-shielding agent and the TPEE matrix decreased sharply, leading to premature fracture due to interfacial peeling under stress. Interfacial defects became channels for aging factors to invade, accelerating matrix degradation. In Comparative Example 9, nano-silica was not added during the preparation of the light-shielding layer. The "micro-reinforcement" effect of nano-silica was missing, reducing the deformation resistance of the TPEE matrix and failing to fill micropores. The reflection and scattering effects of nano-silica on UV light disappeared, accelerating surface aging of the material. In Comparative Example 10, no UV absorber was added during the preparation of the light-shielding layer, which had little impact on the elongation at break. However, the absence of the UV absorber allowed a large amount of ultraviolet light to directly act on the TPEE molecular chains, causing chain breakage and reducing aging resistance. In Comparative Example 11, the light-shielding layer was not prepared by segmented feeding. Instead, TPEE, composite light-shielding agent, maleic anhydride-grafted POE, nano-silica, and UV absorber were simultaneously added to a mixer and treated at 185°C for 13 minutes. Simultaneous feeding resulted in uneven dispersion of the composite light-shielding agent, and the UV absorber decomposed prematurely at high temperature, losing its compatibilizing and protective effects, and increasing internal defects in the material. In Comparative Example 12, when preparing a multilayer TPEE light-shielding material, the outermost layer is a light-shielding layer, the middle layer is a reinforcing layer, and the innermost layer is an aging-resistant layer. The reinforcing layer is sandwiched between the light-shielding layer and the aging-resistant layer. When the outer light-shielding layer is subjected to stress, it is prone to cracking first and cannot effectively transfer / disperse stress through the middle reinforcing layer, resulting in a decrease in the overall toughness of the material. After the outer light-shielding layer is exposed to the aging environment for a long time, its TPEE matrix is ​​prone to embrittlement, and the interfacial bonding force with the middle reinforcing layer is further reduced.

[0075] Example 6

[0076] The preparation method and parameters of Example 4 are the same, except that when preparing the aging-resistant layer, the amount of light stabilizer is 1.2 parts, the amount of ultraviolet absorber UV 327 is 2 parts, the amount of antioxidant 1010 is 1 part, the casting speed is 6m / min, the composite temperature of the multilayer TPEE light-shielding material is 185℃, and the pressure is 9MPa.

[0077] Example 7

[0078] The preparation method and parameters of Example 4 are the same, except that when preparing the aging-resistant layer, the amount of light stabilizer is 1.5 parts, the amount of ultraviolet absorber UV 327 is 2.5 parts, the amount of antioxidant 1010 is 1.25 parts, the casting speed is 8m / min, the composite temperature of the multilayer TPEE light-shielding material is 190℃, and the pressure is 10MPa.

[0079] Comparative Example 13

[0080] The preparation method and parameters of Example 4 are the same, except that UV absorber UV 327 was not added when preparing the aging-resistant layer.

[0081] Comparative Example 14

[0082] The preparation method and parameters of Example 4 are the same, except that the light stabilizer HALS 770 was not added when preparing the aging-resistant layer.

[0083] Comparative Example 15

[0084] The preparation method and parameters of Example 4 are the same, except that polytetrafluoroethylene powder was not added when preparing the aging-resistant layer.

[0085] Comparative Example 16

[0086] The preparation method and parameters of Example 4 are the same, except that antioxidant 1010 was not added when preparing the aging-resistant layer.

[0087] Experiment Example 3: Aging Resistance Test

[0088] The aging resistance was tested according to the method in Experiment Example 2; the results are shown in Table 3.

[0089] Table 3. Aging resistance test results of Examples 4, 6-7 and Comparative Examples 13-16

[0090] Group Elongation at break retention rate / % Example 4 95.2 Example 6 95.8 Example 7 95.4 Comparative Example 13 80.6 Comparative Example 14 75.3 Comparative Example 15 89.5 Comparative Example 16 84.2

[0091] As shown in Table 3, in Examples 4 and 6-7, the TPEE matrix is ​​used as the base, and the polytetrafluoroethylene powder is uniformly dispersed to form a dense physical barrier, which can effectively block the intrusion of aging factors such as oxygen and water vapor, and reduce the erosion of the material interior by the external environment. The light stabilizer HALS 770 can capture free radicals generated during the aging process, terminate the free radical chain reaction, and delay the degradation of TPEE molecular chains. The ultraviolet absorber UV 327 can preferentially absorb ultraviolet light to avoid ultraviolet light directly damaging the matrix structure. The antioxidant 1010 can remove peroxides generated by thermal oxidation and block the thermal oxidative aging path. In addition, the acrylate leveling agent ensures the uniformity of film formation and avoids the formation of aging weak points due to film defects. The synergistic effect of each component can comprehensively resist aging caused by factors such as ultraviolet light, heat, and humidity. The elongation at break of the prepared material can reach 95.8%. When microcracks develop in the material due to UV and thermal aging, the microcapsules rupture to release the dicyclopentadiene core material, which cross-links and solidifies under the action of a catalyst, preventing crack propagation and avoiding the cracks becoming channels for the intrusion of aging factors (oxygen, water vapor). In Example 13, no UV absorber was added when preparing the aging-resistant layer, and a large amount of UV light directly acted on the TPEE molecular chains, inducing chain breakage and cross-linking, accelerating material embrittlement. In Example 14, no light stabilizer HALS 770 was added when preparing the aging-resistant layer. UV light acted on the TPEE matrix, generating a large number of free radicals in a short time, accelerating material embrittlement and yellowing, and significantly reducing aging resistance. During the formation of the aging-resistant layer, PTFE powder is uniformly dispersed and forms a dense microscopic "isolation layer," blocking the contact between aging media such as oxygen and water vapor and the TPEE matrix. It also reduces the transmission of ultraviolet light to the material surface. In Example 15, PTFE powder was not added during the preparation of the aging-resistant layer, resulting in the disappearance of the physical barrier and an accelerated intrusion rate of aging media. Although this does not directly affect the free radical reaction, it amplifies the protective pressure on the light stabilizer, leading to a moderate decrease in aging resistance. In Comparative Example 16, antioxidant 1010 was not added during the preparation of the aging-resistant layer, exacerbating the heat-induced oxidation reaction, especially at high temperatures, which accelerated the degradation rate of the TPEE molecular chains.

[0092] Experiment Example 4: Light-blocking performance test

[0093] The visible light transmittance and infrared transmittance were tested using an LS183 optical transmittance meter; the results are shown in Table 4.

[0094] Table 4. Thermal insulation and light-blocking performance tests of Examples 1-7

[0095] Group Visible light transmittance / % Infrared transmittance / % Example 1 8 15 Example 2 7 14 Example 3 9 15 Example 4 5 11 Example 5 6 13 Example 6 5 10 Example 7 7 11

[0096] As shown in Table 4, in Examples 1-7, the light-shielding layer uses TPEE as the matrix and adds a composite light-shielding agent composed of rutile TiO2 and zirconium oxide. Rutile TiO2, with its high refractive index, strongly scatters visible light, while zirconium oxide supplements the absorption of near-infrared light. The combination of the two covers a broad spectrum of "visible light + near-infrared light," solving the problem of narrow light-shielding range of a single light-shielding agent. The aluminate coupling agent modification ensures uniform dispersion of the light-shielding agent, avoiding agglomeration and the formation of light-transmitting gaps. Combined with the assistance of nano-silica micro-scattering, the light-shielding uniformity is further improved. At the same time, the reinforcing layer PET and modified particles can scatter a small amount of transmitted light a second time, and the aging-resistant dense film layer initially blocks light. The three layers are stacked to form a light-shielding system of "initial blocking - core blocking - secondary scattering," which not only ensures high light-shielding efficiency but also avoids performance fluctuations caused by relying solely on the light-shielding layer. The resulting light-shielding material has a visible light transmittance of 5%-9% and an infrared transmittance of 10%-15%.

[0097] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a multilayer TPEE light-shielding material, characterized in that: The preparation method is as follows: PET, modified alumina, silane-modified aluminum borate whiskers, compatibilizer, and antioxidant were mixed in a high-speed mixer, then water-cooled and pelletized in a twin-screw extruder. The pellets were then vacuum-dried at 80°C for 2 hours to obtain a reinforced material. This reinforced material was then pressed using a hot press to obtain a reinforcing layer. TPEE was added to an internal mixer, along with a composite opacifier and maleic anhydride-grafted POE. The mixture was heated to 185°C and stirred for 5 minutes. Nano-silica and UV absorber were then added, and the mixture was cooled to 170°C and stirred. After discharge, the mixture was hot-pressed. A light-shielding layer is obtained; the TPEE, polytetrafluoroethylene powder, light stabilizer, UV absorber II, antioxidant and leveling agent are added to DMF, ball-milled and dispersed, cast into a film on release paper and subjected to step drying, and peeled off to obtain an aging-resistant layer; the reinforcing layer, the light-shielding layer and the aging-resistant layer are stacked in sequence and placed in a hot press laminating machine, with a lamination temperature of 180-190℃, a lamination pressure of 8-10MPa, a holding time of 5min, and after the holding time is completed, the temperature is lowered, and after demolding, the multi-layer structure TPEE light-shielding material is obtained; The modified alumina was obtained by spray coating α-Al2O3 powder with a silane coupling agent KH550 solution; The composite opacifier is prepared as follows: rutile TiO2 and zirconium oxide are mixed and ball-milled, an aluminate coupling agent is added, the mixture is heated to 80°C and stirred, and then sieved to obtain the composite opacifier.

2. The method for preparing a multilayer TPEE light-shielding material according to claim 1, characterized in that: The modified alumina is prepared as follows: the α-Al2O3 powder is vacuum dried, cooled, and then spray-coated with the silane coupling agent KH550 solution, followed by thermosetting to obtain the modified alumina.

3. The method for preparing a multilayer TPEE light-shielding material according to claim 1, characterized in that: The method for preparing the silane-modified aluminum borate whiskers is as follows: aluminum borate whiskers are added to a 5wt% KH570 ethanol solution and ultrasonically dispersed, and then cured by heat treatment to obtain the silane-modified aluminum borate whiskers.

4. A multi-layered TPEE light-shielding material, characterized in that: The multi-layered TPEE light-shielding material is prepared by the preparation method described in any one of claims 1-3.

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