Reactive ultraviolet light composite stabilizer and application thereof in TPEE

Abstract

This invention relates to the field of polymer material additives technology, and discloses a reactive ultraviolet composite stabilizer and its application in TPEE. The aim is to solve the problem that traditional physical blending light stabilizers are prone to migration and volatilization, leading to insufficient long-term weather resistance of polymers. This invention designs and synthesizes a composite stabilizer with primary hydroxyl groups retained at both ends of the molecule, using dibromoneopentyl glycol as the backbone and connecting its two ends of bromine atoms to hindered amine derivatives containing hydroxyl groups and triazine ultraviolet-absorbing derivatives via ether bonds. This stabilizer can be used as a comonomer, achieving permanent bonding and fixation during the polycondensation process of TPEE through the chemical embedding of its two primary hydroxyl groups into the polymer backbone. This allows it to exert non-migrating properties and the synergistic effect of the intramolecular hindered amine and ultraviolet-absorbing groups, thereby improving the anti-ultraviolet aging performance and long-term stability of TPEE products.

Description

Technical Field

[0001] This invention relates to the field of polymer material additives technology, and in particular to a reactive ultraviolet composite stabilizer and its application in TPEE. Background Technology

[0002] Polymer materials, especially thermoplastic polyester elastomers (TPEE), are susceptible to yellowing, embrittlement, and mechanical property degradation due to UV oxidative aging in outdoor applications. Currently, the widely used protective method is to physically blend small-molecule hindered amine light stabilizers or UV absorbers with the resin matrix. However, these additives are mainly bonded to the polymer through van der Waals forces, and are prone to migration, volatilization, or extraction under the influence of heat, light, and solvents, resulting in rapid decay of protective function and insufficient long-term stability of the material.

[0003] To overcome migration problems, the industry has developed reactive light stabilizers, which introduce functional groups such as hydroxyl, epoxy, and isocyanate groups into the auxiliary molecule that can participate in polymerization and fix them to the polymer chain through covalent bonds. Although such single-function reactive auxiliary molecule can effectively prevent migration, there are still obvious limitations. Each molecule only has one function: free radical capture or ultraviolet absorption. The protection mechanism is singular. Even if two reactive hindered amines with different reactive groups are mixed with reactive ultraviolet absorbers, they are still in a random and isolated distribution in the polymer matrix, making it difficult to achieve sufficient molecular-level synergy. Moreover, different reactive groups may compete during polymerization due to differences in activity, resulting in uneven grafting efficiency and poor controllability of the final product performance.

[0004] In recent years, further research has focused on introducing multifunctional reactive additive systems into the polymerization stage. For example, existing technologies simultaneously add hindered amines containing epoxy groups and ultraviolet absorbers containing isocyanate groups during the TPEE polycondensation process, attempting to achieve long-lasting stability through chemical bonding. Although this approach is an improvement over physical blending, it is essentially still a simple physical combination of monomers with different structures and reaction characteristics. It fails to achieve functional integration from the molecular design source. The independent reaction of the two additives may lead to competition and disordered distribution of grafting sites, affecting the uniformity of the material structure. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to develop a stabilizer molecule that can simultaneously integrate the dual functions of hindered amine photostability and ultraviolet absorption, and has a symmetrical double primary hydroxyl structure, so as to serve as a uniform comonomer, efficiently and quantitatively embedding into the polymer backbone to achieve long-lasting, stable and highly efficient anti-ultraviolet aging performance. To this end, we propose a reactive ultraviolet composite stabilizer and its application in TPEE.

[0006] To achieve the above objectives, this application adopts the following technical solution: a reactive ultraviolet composite stabilizer having the following structure: R1 is selected from any one of -H, -CH3, -CH2CH3, -OH, and -OR, while R2 and R3 are each independently selected from any one of -H, -OH, -CH3, -CH2CH3, and -Ar, and the molecules are composed of primary hydroxyl groups at both ends.

[0007] Preferably, R1 is -H or -CH3, R2 is -H, -OH or -CH3, and R3 is -H, -CH3 or -Ar.

[0008] Preferably, the composite stabilizer is composed of dibromoneopentyl glycol, 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative and triazine derivative in a molar ratio of 1:1:1.

[0009] Preferably, the 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative has the following structure: R1 is selected from any one of -H, -CH3, -CH2CH3, -OH, and -OR.

[0010] Preferably, the triazine derivative has the following structure: R2 and R3 are each independently selected from -H, -OH, -CH3, -CH2CH3, and -Ar.

[0011] A method for preparing a reactive ultraviolet composite stabilizer includes the following steps: S1: Dissolving dibromoneopentyl glycol in a solvent under inert gas protection; S2: Adding a 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative and a portion of an alkaline catalyst to the solution obtained in S1, and reacting at 60-100℃ under alkaline conditions for 2-10 h; S3: Adding a triazine derivative and the remaining alkaline catalyst to the reaction system obtained in S2, and continuing the reaction at 60-100℃ under alkaline conditions for 4-18 h; S4: Filtering, extracting, washing, and vacuum drying the reaction mixture obtained in S3 sequentially to obtain the target product.

[0012] Preferably, the alkaline catalyst is selected from potassium carbonate, sodium carbonate, and sodium hydride, and the amount of alkaline catalyst added is 1.5-2.5 times the total molar amount of the dibromoneopentyl glycol, the 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative, and the triazine derivative.

[0013] Preferably, the solvent is a polar aprotic solvent selected from dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, and acetone.

[0014] The application of a reactive ultraviolet composite stabilizer in TPEE is characterized in that: in the synthesis of TPEE, a portion of the chain extender 1,4-butanediol is replaced by the stabilizer in equimolar proportion, with a substitution molar ratio of 2%-10%.

[0015] Preferably, the specific method of application is as follows: during the esterification stage of TPEE, the reactive ultraviolet composite stabilizer is first added to participate in the reaction for 2 hours, and then the remaining 1,4-butanediol is added to continue the polycondensation reaction.

[0016] The technical effects and advantages of this invention are as follows: In this invention, a novel single compound with both hindered amine radical capture and triazine UV absorption functions, and symmetrical primary hydroxyl groups at both ends, is created through chemical synthesis. This stabilizer molecule can serve as a structurally uniform bifunctional comonomer. During the polycondensation of TPEE, it can be directly and quantitatively embedded into the polymer backbone like a standard monomer through its symmetrical and equally active dihydroxyl groups, achieving chemical bonding and fixation. This avoids the problems of reaction competition, uneven grafting, and random distribution of functional groups that may exist in multi-component systems. It achieves non-migratory long-term residence of the stabilizer in the polymer and exerts the close synergistic effect of the intramolecular bifunctional groups, thereby improving the durability, stability, and efficiency of the material's UV aging resistance, while maintaining good mechanical properties of the matrix. Attached Figure Description

[0017] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 The proton nuclear magnetic resonance spectrum of the product prepared in Example 1 of this invention; Figure 2 The carbon nuclear magnetic resonance spectrum of the product prepared in Example 1 of this invention; Figure 3 The proton nuclear magnetic resonance spectrum of the product prepared in Example 2 of this invention; Figure 4 The carbon NMR spectrum of the product prepared in Example 2 of this invention; Figure 5 The proton nuclear magnetic resonance spectrum of the product prepared in Example 3 of this invention; Figure 6 The image shows the carbon NMR spectrum of the product prepared in Example 3 of this invention. Detailed Implementation

[0018] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0019] This invention provides a reactive ultraviolet composite stabilizer having a molecular structure as shown in formula (I): In formula (Ⅰ), R1 is selected from -H, -CH3, -CH2CH3, -OH, and -OR groups, and R1 is preferably -H or -CH3; R2 and R3 are each independently selected from -H, -OH, -CH3, -CH2CH3, and -Ar, wherein R2 is preferably -H, -OH, or -CH3, and R3 is preferably -H, -CH3, or -Ar; It should be noted that R in -OR is an alkyl group, which includes, but is not limited to, straight-chain or branched alkyl groups of C1-C12, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, octyl, dodecyl, etc. The Ar in -Ar is an aryl or substituted aryl group, wherein the aryl group is selected from phenyl, naphthyl, and biphenyl, and the substituted aryl group refers to a group formed by replacing one or more hydrogen atoms on the above-mentioned aromatic ring with C1-C4 alkyl, hydroxyl, or halogen atoms, such as methylphenyl, dimethylphenyl, hydroxyphenyl, chlorophenyl, etc.

[0020] The reactive ultraviolet composite stabilizer uses dibromonepentylene glycol as a bifunctional reactive framework. The bromine atoms at both ends of its molecule are electrophilic and can serve as reaction sites. Under alkaline catalytic conditions, the bromine atoms can be replaced by nucleophiles containing hydroxyl groups, resulting in the synthesis of Williamson ether. Furthermore, the present invention uses dibromoneopentyl glycol, 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative and triazine derivative in a molar ratio of 1:1:1 as reaction raw materials for stepwise etherification synthesis; Specifically, one bromine atom on the skeleton reacts with the hydroxyl group of the 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative to form the first ether bond. Then, another bromine atom on the skeleton reacts with the hydroxyl group of the triazine derivative to form the second ether bond. Thus, the two functional monomers are directionally linked to both sides of the dibromonepentylene glycol skeleton via ether bonds. In this process, the carbon atoms originally attached to bromine atoms on the dibromonepentylene glycol skeleton are converted into methylene groups (-CH2O-) attached to the ether bonds after the reaction, while the hydroxymethyl groups (-CH2OH) at both ends of the skeleton are retained throughout the reaction, so that the final product still has two primary hydroxyl groups.

[0021] It should be noted that the 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative, as a hindered amine monomer, is a compound having the molecular structure shown in formula (II): In formula (II), R1 is selected from -H, -CH3, -CH2CH3, -OH, and -OR groups, preferably -H or -CH3.

[0022] The triazine derivative, as an ultraviolet-absorbing monomer, is a compound having the molecular structure shown in formula (Ⅲ): In formula (Ⅲ), R2 and R3 are each independently selected from -H, -OH, -CH3, -CH2CH3, and -Ar, where Ar is an aryl group, R2 is preferably -H, -OH, or -CH3, and R3 is preferably -H, -CH3, or -Ar.

[0023] The dibromoneopentyl glycol is a compound having the molecular structure shown in formula (Ⅳ): The alkaline catalyst is used to neutralize the hydrogen bromide produced in the reaction, shifting the reaction equilibrium to the right, and can preferably be selected from potassium carbonate, sodium carbonate, and sodium hydride.

[0024] It should also be noted that, in order for the reaction to proceed smoothly, a solvent is required to dissolve all the reactants. The solvent is a polar aprotic solvent selected from dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), acetonitrile (CH3CN), and acetone, preferably DMF.

[0025] This invention also provides a method for preparing a reactive ultraviolet composite stabilizer, specifically including the following steps: S1: Dissolve dibromoneopentyl glycol in a solvent under inert gas protection; S2: Add 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative and part of the alkaline catalyst to the solution obtained in S1, and react at 60-100℃ under alkaline conditions for 2-10 h to complete the first step of etherification; S3: Add the triazine derivative and the remaining alkaline catalyst to the reaction system obtained in S2, and continue the reaction at 60-100℃ under alkaline conditions for 4-18 hours to complete the second step of etherification; S4: The reaction mixture obtained in S3 is sequentially filtered, extracted, washed, and vacuum dried to obtain the target product.

[0026] Specifically, the inert gas mentioned in S1 is selected from helium, argon, and nitrogen, preferably nitrogen; In S2 and S3, the reaction temperature is preferably 70-90℃, and the reaction time is preferably 3-6h and 6-10h, respectively. In S2 and S3, the total amount of alkaline catalyst added is 1.5-2.5 times, preferably 2.0-2.2 times, of the total molar amount of the reaction monomers, to ensure that the pH value of the reaction system is maintained at 8-10.

[0027] This invention also provides an application of a reactive ultraviolet composite stabilizer in TPEE. Specifically, during the synthesis of TPEE, the reactive ultraviolet composite stabilizer obtained through the above preparation process is used to equimolarly replace part of the chain extender 1,4-butanediol (BDO), with a substitution molar ratio of 2%-10%. Specifically, at the beginning of the polymerization stage, the reactive UV composite stabilizer, which replaces the amount of BDO, is added first. After reacting for 2 hours, BDO is added again. The reaction is then completed according to the conventional TPEE polycondensation process to obtain the TPEE material in which the stabilizer is chemically embedded in the molecular chain.

[0028] The present invention will be further described below with reference to the embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0029] Those skilled in the art can make conventional adjustments to the methods and conditions without departing from the concept of the present invention, and such adjustments should also be considered to fall within the protection scope of the present invention. Example

[0030] This embodiment uses the above-described preparation method to prepare a reactive ultraviolet composite stabilizer, specifically including the following steps: S1: Under nitrogen protection, add 200 mL of anhydrous N,N-dimethylformamide and 26.20 g of dibromoneopentyl glycol to a dry 500 mL three-necked flask, and stir until completely dissolved; S2: Add 15.71 g of 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative and 30 g of anhydrous potassium carbonate (K2CO3) to the above solution. Under nitrogen protection, heat the mixture to 85°C and maintain the reaction for 4 h. During this period, add K2CO3 to keep the pH of the reaction solution at 9.0. S3: Keep the temperature at 85℃, add 34.13g of triazine derivative to the reaction system, and add 15g of K2CO3. Continue to react under nitrogen protection for 6h, and maintain the pH value at 9.0. S4: After the reaction is complete, cool to room temperature, pour the reaction solution into 800 mL of ice-water mixture and stir to precipitate solid. Collect the solid by vacuum filtration, wash the filter cake with water, transfer it to a round-bottom flask, add 250 mL of anhydrous ethanol, heat to reflux to dissolve the solid, filter while hot to remove insoluble matter, cool the filtrate in an ice-water bath to recrystallize, filter again, wash the crystals with cold ethanol, and finally dry at 60 °C under vacuum for 12 h to obtain a white solid product.

[0031] It should be noted that the 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative used in the above preparation process has the following molecular structure as shown in formula (V): The triazine derivatives used have the following molecular structure (VI): The reactive ultraviolet composite stabilizer prepared in this embodiment has the molecular structure shown in formula (VII): The obtained product was subjected to proton nuclear magnetic resonance spectroscopy (NMR). 1 H-NMR and carbon spectrum ( 13 C-NMR analysis, the spectra are shown in […]. Figure 1 and Figure 2 . Example

[0032] The difference between this embodiment and Example 1 is that, in S3, the added triazine derivative is replaced with 39.7g of a compound having the structure shown in formula (VIII), and the amount used is the same as the molar amount of the triazine derivative in Example 1. The reactive ultraviolet composite stabilizer prepared in this embodiment has the molecular structure shown in formula (IX): The obtained product was subjected to proton nuclear magnetic resonance spectroscopy (NMR). 1 H-NMR and carbon spectrum ( 13 C-NMR analysis, the spectra are shown in […]. Figure 3 and Figure 4 . Example

[0033] The difference between this embodiment and Example 1 is that, in S3, the added triazine derivative is replaced with 49.3g of a compound having the structure shown in formula (X), and the amount used is the same as the molar amount of the triazine derivative in Example 1; The reactive ultraviolet composite stabilizer prepared in this embodiment has the molecular structure shown in formula (XI): The obtained product was subjected to proton nuclear magnetic resonance spectroscopy (NMR). 1 H-NMR and carbon spectrum ( 13 C-NMR analysis, the spectra are shown in […]. Figure 5 and Figure 6 .

[0034] The following performance comparison experiments verify the application effect of the reactive ultraviolet composite stabilizer comonomer described in this invention in the synthesis of TPEE. Unless otherwise specified, the chemical reagents, raw materials and analytical testing equipment used in the experiments are all conventional products that can be purchased through commercial channels.

[0035] Based on the preparation of TPEE with a Shore D hardness of 40, 8.32 kg of purified terephthalic acid (PTA) and 5.86 kg of 1,4-butanediol (BDO) were added sequentially as hard segments in a 20 L polymerization reactor, 6.86 kg of polytetrahydrofuran ether glycol (PTMEG) was added as soft segments, and 8.5 kg of tetrabutyl titanate was added as a catalyst, controlling the mass fraction of hard segments to be 48%. Esterification was carried out at 240°C under a nitrogen atmosphere, with the pressure maintained at 60 kPa. After esterification, the pressure was gradually reduced to <100 Pa, and polymerization was carried out at 240°C until the stirring torque reached 30 N·m as the reaction endpoint. The discharged material was then cast, cooled, pelletized, and dried to obtain TPEE base resin.

[0036] Based on the above process, six sets of comparative samples were prepared by changing the type and introduction method of the anti-aging additives. Ten parallel samples were set up in each set, and the average value of the results was taken. The control group D1 was a blank sample, with no stabilizers added. The control group D2 used D1 base resin as the base material, and melt-blended 0.4 wt% of commercially available hindered amine light stabilizer Tinuvin-770 and 0.4 wt% of triazine ultraviolet absorber Tinuvin-1577 into it in a twin-screw extruder, and then granulated to obtain the sample. In the initial stage of the polymerization reaction, two commercially available reactive additives with reactive functional groups were added to the reaction system in control group D3. Specifically, the hindered amine light stabilizer Tinuvin-770 containing hydroxyl groups and the ultraviolet absorber Tinuvin-400 containing hydroxyl groups were added. The total amount of the two additives added, based on the number of moles of their functional groups, was equal to the total number of moles of hydroxyl groups in the stabilizers in the subsequent experimental group. In the initial stage of the polymerization reaction, the stabilizer prepared in Example 1 was added to experimental group E1. The amount added was 4% of the total molar amount of BDO used. Since the reactive ultraviolet composite stabilizer provided by the present invention has a larger steric hindrance than BDO, it is necessary to pre-condense at 240°C and low vacuum for 2 hours after the esterification reaction is completed and before vacuuming, so as to ensure that the stabilizer molecules can fully participate in the reaction and embed into the polymer backbone. Then BDO was added to continue vacuum polycondensation. The preparation method of experimental group E2 is the same as that of experimental group E1, except that the stabilizer prepared in Example 2 is used, and the amount added is also 4% of the total moles of BDO; The preparation method of experimental group E3 is the same as that of experimental group E1, except that the stabilizer prepared in Example 3 is used, and the amount added is also 4% of the total moles of BDO.

[0037] After injection molding, the initial properties, UV aging resistance, and migration resistance of each group of TPEE samples were tested sequentially. The initial mechanical properties are shown in Table 1.

[0038]

[0039] Table 1 According to the data in Table 1, the initial mechanical properties and melt flowability of each group of samples are at similar levels, which indicates that the introduction of various stabilizer systems during the polymerization stage has not damaged the matrix properties of TPEE.

[0040] Subsequently, the samples underwent accelerated aging tests in a xenon lamp aging chamber, with conditions conforming to ISO 4892-2 standard, and an irradiance of 1.25 W / (m²). 2 The control wavelength is 420nm, the blackboard temperature is 100℃, the chamber temperature is 65±2℃, and the relative humidity is 50±5%.

[0041] After aging, color difference tests were conducted on the samples using a colorimeter, referring to the CIE 1976 L*a*b color space standard in ISO 11664-4:2008. A D65 standard light source, a 10° viewing angle, and an 8mm measuring aperture were used. Five different locations were tested for each sample, and the arithmetic mean was taken as the color difference value for that sample. The color difference ΔE and tensile strength retention rate test results after different aging times are shown in Table 2.

[0042]

[0043] Table 2 According to the data in Table 2, after 649 hours of aging, E1-E3 outperformed D1-3 in both anti-yellowing and mechanical property retention.

[0044] To assess the strength of the bond between the stabilizer and the polymer matrix, the sample was immersed in n-hexane at 60°C for 168 h, and its mass loss rate was measured. The extract was analyzed using a UV-Vis spectrophotometer. The mass loss rate and the UV absorption intensity of the extract can directly reflect the anti-migration ability of different stabilizer systems. The results are shown in Table 3 below.

[0045]

[0046] Table 3 According to the data in Table 3, the mass loss rate of E1 was significantly lower than that of D2 and D3, and no obvious adjuvant characteristic absorption was detected in the extract, indicating that stabilizers with bis-primary hydroxyl groups embedded in the main chain are an effective way to achieve long-term weather resistance.

[0047] More importantly, the reactive UV composite stabilizer molecule provided by this invention has two primary hydroxyl groups, which ensures that it can be quantitatively and stably embedded into the polymer backbone in a uniform manner similar to monomer units during the polycondensation reaction. In contrast, although the two auxiliaries used in D3 both contain hydroxyl groups and can participate in the polycondensation reaction as reactive auxiliaries, they are independent molecules and randomly attach to the polymer chain during the polymerization process. Their attachment positions and distribution are difficult to control precisely, thus affecting the uniformity and stability of the final material. Meanwhile, the present invention integrates the hindered amine and the ultraviolet absorbing group into a molecular backbone through stable covalent bonds. In contrast, the two functional auxiliaries in D3 are physically mixed independent molecules. Even if they can be chemically integrated into the polymer, their distribution in the matrix is ​​still random. The two functional units need to rely on intermolecular collisions to achieve synergy, and their synergy efficiency is lower than that of the intramolecular structure-based synergy in the present invention.

[0048] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A reactive ultraviolet composite stabilizer, characterized in that, It has the following structure: Wherein, R1 is selected from any one of -H, -CH3, -CH2CH3, -OH, -OR, where R in -OR is an alkyl group, R2 and R3 are each independently selected from any one of -H, -OH, -CH3, -CH2CH3, -Ar, where -Ar is an aryl or substituted aryl group, and the stabilizer molecule has primary hydroxyl groups at both ends.

2. The reactive ultraviolet composite stabilizer according to claim 1, characterized in that: R1 is -H or -CH3, R2 is -H, -OH or -CH3, and R3 is -H, -CH3 or -Ar.

3. The reactive ultraviolet composite stabilizer according to claim 1, characterized in that: The composite stabilizer is composed of dibromoneopentyl glycol, 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative and triazine derivative in a molar ratio of 1:1:

1.

4. The reactive ultraviolet composite stabilizer according to claim 3, characterized in that: The 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative has the following structure: Wherein, R1 is selected from any one of -H, -CH3, -CH2CH3, -OH, and -OR, and R in -OR is an alkyl group.

5. A reactive ultraviolet composite stabilizer according to claim 3, characterized in that: The triazine derivative has the following structure: R2 and R3 are each independently selected from -H, -OH, -CH3, -CH2CH3, and -Ar, wherein -Ar is an aryl or substituted aryl group.

6. A method for preparing a reactive ultraviolet composite stabilizer as described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Dissolve dibromoneopentyl glycol in a solvent under inert gas protection; S2: Add 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative and part of the alkaline catalyst to the solution obtained in S1, and react for 2-10 h at 60-100 °C under alkaline conditions. S3: Add the triazine derivative and the remaining alkaline catalyst to the reaction system obtained in S2, and continue the reaction at 60-100℃ under alkaline conditions for 4-18 hours; S4: The reaction mixture obtained in S3 is sequentially filtered, extracted, washed, and vacuum dried to obtain the target product.

7. The method for preparing a reactive ultraviolet composite stabilizer according to claim 6, characterized in that: The alkaline catalyst is selected from potassium carbonate, sodium carbonate, and sodium hydride, and the amount of alkaline catalyst added is 1.5-2.5 times the total molar amount of dibromonepentylene glycol, 4-hydroxy-2,2,6,6-tetramethylpiperidine derivative and triazine derivative.

8. The method for preparing a reactive ultraviolet composite stabilizer according to claim 6, characterized in that: The solvent is a polar aprotic solvent, selected from one of dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, and acetone.

9. The application of a reactive ultraviolet composite stabilizer as described in any one of claims 1-5 in TPEE, characterized in that: In the synthesis of TPEE, the stabilizer is used to replace part of the chain extender 1,4-butanediol in an equimolar ratio of 2%-10%.

10. The application of a reactive ultraviolet composite stabilizer according to claim 9 in TPEE, characterized in that: The specific application method is as follows: during the esterification stage of TPEE, the reactive ultraviolet composite stabilizer is first added to participate in the reaction for 2 hours, and then the remaining 1,4-butanediol is added to continue the polycondensation reaction.

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