Anti-ultraviolet powder as well as preparation method and application thereof

Abstract

The invention discloses anti-ultraviolet powder as well as a preparation method and application thereof. The anti-ultraviolet powder is prepared from the following components in parts by mass: 80 to 95 parts of PET (Polyethylene Terephthalate) matrix; 3 to 8 parts of modified MOF powder; 1-3 parts of a dispersant; wherein the modified MOF powder comprises a porous crystal skeleton and a surfactant at least adsorbed on the porous crystal skeleton, and the surfactant is adsorbed on the surfaces of particles in the MOF nucleation and growth process to realize in-situ surface modification, so that the compatibility of the modified MOF powder with a PET matrix is improved, a group with good compatibility with the PET matrix is introduced into the surface of the modified MOF powder, and the surface of the modified MOF powder is modified. The two-phase compatibility is greatly improved, the tensile strength of the membrane material is improved by virtue of a nano-enhancement effect, and good balance between optical properties and mechanical properties is realized.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of PET, in particular to an ultraviolet-proof powder, a preparation method and application. BACKGROUND

[0002] Polyethylene terephthalate (PET) is widely used as an optical film base material due to excellent mechanical strength, light transmittance and chemical stability. However, the ester bond in the molecular structure of PET is prone to degradation under ultraviolet light, which causes yellowing, embrittlement and a decrease in light transmittance of the optical film, and seriously affects the service life and performance of the optical film. Therefore, it is crucial to develop efficient and stable ultraviolet-proof PET masterbatch to improve the market competitiveness of the PET optical film.

[0003] At present, the ultraviolet-proof modification of the PET masterbatch is mainly achieved by adding organic ultraviolet absorbers or inorganic ultraviolet shielding agents. Although the organic ultraviolet absorbers (such as benzotriazole and benzophenone) have good initial effect, they have defects such as poor heat resistance, easy migration and precipitation, and insufficient long-term weather resistance, and are prone to failure during high-temperature extrusion processing and long-term use. Although the inorganic ultraviolet shielding agents (such as TiO2 and ZnO nanoparticles) have excellent weather resistance, they have poor compatibility with the PET matrix and are prone to agglomeration, which leads to a decrease in the light transmittance of the optical film and cannot meet the use requirements of high-end optical films.

[0004] Current research attempts to use MOF for polymer modification, but does not effectively modify the surface of MOF, only relies on physical mixing and a small amount of dispersant, and does not utilize the ultraviolet absorption properties of MOF. In addition, the filler system cannot meet the high light transmittance requirements of high-end optical films due to the light scattering effect of metal particles. Furthermore, the surface polarity of pure MOF powder is quite different from the PET matrix, and direct addition can cause uneven dispersion and poor compatibility, which limits its use as an anti-ultraviolet powder in PET masterbatch. Therefore, how to optimize the compatibility of MOF and PET through modification while retaining its efficient ultraviolet-proof performance has become a key research issue. SUMMARY

[0005] The main purpose of the present application is to provide an ultraviolet-proof powder, a preparation method and application, which aims to solve the problems of poor compatibility between the ultraviolet shielding agent and the PET matrix, unstable ultraviolet-proof performance, and affected light transmittance of the optical film in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides an ultraviolet-proof powder, which comprises the following components by mass: 80-95 parts of a PET matrix; 3-8 parts of a modified MOF powder; 1-3 parts of a dispersant; The modified MOF powder includes a porous crystal framework and at least an active layer covering the porous crystal framework, wherein the porous crystal framework is formed by the self-assembly of a metal source and an organic ligand through coordination bonds.

[0007] In one embodiment, the specific surface area of ​​the porous crystal framework is 400–1800 m² / g; and / or, The pore size distribution of the porous crystal framework is concentrated in the range of 0.5–2.0 nm; and / or, The modified MOF powder has a D10 of less than 0.5 μm, a D50 of less than 0.8 μm, and a D90 of less than 1.2 μm.

[0008] In one embodiment, the PET matrix comprises PET particles or PET chips; and / or, The metal source includes at least one selected from aluminum nitrate, aluminum sulfate, zinc nitrate, zinc acetate, cerium nitrate, magnesium nitrate, and copper sulfate; and / or, The organic ligand comprises at least one of fumaric acid, terephthalic acid, and 2-methylimidazole; and / or the dispersant comprises at least one of polyethylene glycol, stearamide, and vinyl bis-stearamide.

[0009] This invention provides a method for preparing a UV-protective powder, the method comprising the following steps: S10. Mix and stir the PET matrix, modified MOF powder and dispersant to obtain the first mixture; S20. The first mixture is extruded and granulated to obtain the second mixture; S30. The second mixture is cut and dried to obtain a UV-resistant powder.

[0010] In one embodiment, the method for preparing the modified MOF powder includes: S101. Mix the surfactant with the metal source to obtain a pre-dispersion; S102. The pre-dispersed liquid is mixed with the organic ligand under alkaline conditions to obtain modified MOF powder.

[0011] In one embodiment, the surfactant is at least one selected from sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and dodecyltrimethylammonium chloride.

[0012] In one embodiment, the molar ratio of the metal source to the surfactant is 1:0.1 to 1:0.4; and / or, The molar ratio of the metal source to the organic ligand is 1:0.5 to 1:4.

[0013] In one embodiment, the mixing temperature is 60-80°C; and / or, The mixing time is 5-10 min; and / or, The stirring speed includes 800~1200 r / min.

[0014] In one embodiment, the drying temperature is 80~150°C; and / or, The drying time is 2-6 hours.

[0015] This invention proposes the application of UV-protective powders in optical thin films.

[0016] In the technical solution of this invention, the MOF synthesis process is regulated by pre-binding with surfactants. The surfactants adsorb onto the particle surface during MOF nucleation and growth, achieving in-situ surface modification and improving its compatibility with the PET matrix. This introduces groups with good compatibility with the PET matrix onto the surface of the modified MOF powder, significantly enhancing the two-phase compatibility. The constructed porous crystalline framework MOF itself possesses excellent ultraviolet absorption capabilities. Synergistically combined with ultraviolet absorbers, it can achieve efficient shielding of ultraviolet light in the 200-400nm wavelength band. Furthermore, because the modified MOF powder is tightly bound to the PET matrix and does not easily migrate or precipitate, the yellowing index of the optical film decreases after ultraviolet aging, and its stability is far superior to traditional masterbatches. Simultaneously, the modified MOF powder is uniformly dispersed in the PET matrix, having minimal impact on visible light transmittance. Moreover, the nano-reinforcement effect increases the tensile strength of the film by 10%-15%, achieving a good balance between optical and mechanical properties. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, or solution B, or a solution where both A and B are satisfied simultaneously. In addition, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. 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.

[0018] Current research has attempted to use MOFs for polymer modification. However, effective surface modification of MOFs has not been performed, relying solely on physical mixing and a small amount of dispersant. Furthermore, the UV absorption properties of MOFs have not been utilized, and the filler system cannot meet the high light transmittance requirements of high-end optical films due to the light scattering effect of metal particles. In addition, the surface polarity of pure MOF powder differs significantly from that of the PET matrix, leading to uneven dispersion and poor compatibility when directly added, thus limiting its use as a UV-resistant powder in PET masterbatches. Therefore, optimizing the compatibility of MOFs with PET through modification while retaining their high-efficiency UV protection performance has become a key research focus.

[0019] In view of this, one embodiment of the present invention provides a UV-protective powder, comprising the following components in parts by weight: 80-95 parts of PET matrix; 3 to 8 parts of modified MOF powder; 1-3 parts dispersant; The modified MOF powder includes a porous crystal framework and at least a surfactant adsorbed on the porous crystal framework. The porous crystal framework is formed by the self-assembly of a metal source and an organic ligand through coordination bonds.

[0020] In the technical solution of this invention, the MOF synthesis process is regulated by pre-binding with surfactants. The surfactants adsorb onto the particle surface during MOF nucleation and growth, achieving in-situ surface modification and improving its compatibility with the PET matrix. This introduces groups with good compatibility with the PET matrix onto the surface of the modified MOF powder, significantly enhancing the two-phase compatibility. The constructed porous crystalline framework MOF itself possesses excellent ultraviolet absorption capabilities. Synergistically combined with ultraviolet absorbers, it can achieve efficient shielding of ultraviolet light in the 200-400nm wavelength band. Furthermore, because the modified MOF powder is tightly bound to the PET matrix and does not easily migrate or precipitate, the yellowing index of the optical film decreases after ultraviolet aging, and its stability is far superior to traditional masterbatches. Simultaneously, the modified MOF powder is uniformly dispersed in the PET matrix, having minimal impact on visible light transmittance. Moreover, the nano-reinforcement effect increases the tensile strength of the film by 10%-15%, achieving a good balance between optical and mechanical properties.

[0021] In some embodiments, the specific surface area of ​​the porous crystal framework is 400 to 1800 m² / g, which can effectively capture high-energy ultraviolet photons and adsorb free radicals generated by photodegradation of the substrate, thereby preventing chain reactions caused by photodegradation.

[0022] In some embodiments, the pore size distribution of the porous crystal framework is concentrated in the range of 0.5 to 2.0 nm.

[0023] In some embodiments, the modified MOF powder has a D10 of less than 0.5 μm, a D50 of less than 0.8 μm, and a D90 of less than 1.2 μm. That is, the particle size distribution of the modified MOF powder satisfies: D10 < 0.5 μm, D50 < 0.8 μm, D90 < 1.2 μm, where D10, D50, and D90 represent the particle sizes corresponding to cumulative volume percentages of 10%, 50%, and 90%, respectively. Due to the competitive interaction between the surfactant and the organic ligand, and the steric hindrance effect of the surfactant itself, it is relatively easy to control the particle size and pore size of the modified MOF powder to the submicron level and to concentrate its particle size distribution.

[0024] In some embodiments, the PET matrix includes PET particles or PET chips. The PET matrix may be a form of PET raw material commonly used in the art, including but not limited to PET chips, PET particles, recycled PET fragments, etc., preferably PET particles or PET chips.

[0025] In some embodiments, the metal source includes at least one of aluminum nitrate, aluminum sulfate, zinc nitrate, zinc acetate, cerium nitrate, magnesium nitrate, and copper sulfate. The metal ions in the aforementioned metal sources have strong coordination ability and excellent ultraviolet absorption / reflection characteristics, which endow MOFs with intrinsic ultraviolet resistance while also facilitating hydrothermal synthesis control.

[0026] In some embodiments, the organic ligands include at least one of fumaric acid, terephthalic acid, and 2-methylimidazole. These ligands have strong structural rigidity and high conjugation, enabling the construction of stable porous frameworks and the absorption of ultraviolet light through transitions. Among them, 2-methylimidazole is suitable for ZIFs-type MOFs, possesses excellent chemical stability, is compatible with PET processing temperatures, and allows for the control of the electronic structure and pore environment of MOFs through metal-ligand combinations, thereby achieving ultraviolet protection design.

[0027] In some embodiments, the dispersant includes at least one of polyethylene glycol, stearamide, and vinyl bis-stearamide. It is understood that the above dispersants have lubricity and compatibility. For example, PEG contains ether bonds that can interact with PET segments, and stearamide contains long alkyl chains that can coat MOF particles, thereby reducing surface energy and inhibiting agglomeration. At the same time, it plays an internal lubricating role in the extrusion process, improving melt flowability and reducing equipment wear.

[0028] This invention provides a method for preparing a UV-protective powder, the method comprising the following steps: S10. Mix and stir the PET matrix, modified MOF powder and dispersant to obtain the first mixture; S20. The first mixture is extruded and granulated to obtain the second mixture; S30. The second mixture is cut and dried to obtain a UV-resistant powder.

[0029] In the technical solution of this invention, firstly, the dispersant is melted and coated with modified MOF powder by gentle heating, and high-speed stirring is used to ensure that the components are uniformly mixed to obtain a first mixture. This can avoid excessive local concentration leading to degradation or color difference during extrusion. Then, the mixture is extruded and granulated, and the MOF nanoparticles are fully dispersed in the PET melt by shearing and mixing to form a stable masterbatch. The entire manufacturing process is simple, easy to scale up, and can expand production.

[0030] In some embodiments, the method for preparing the modified MOF powder includes: S101. Mix the surfactant with the metal source to obtain a pre-dispersion; S102. The pre-dispersed liquid is mixed with the organic ligand under alkaline conditions to obtain modified MOF powder.

[0031] In the technical solution of the present invention, the MOF is synthesized by hydrothermal coprecipitation, which is simple in process and low in equipment requirements. By modifying the MOF material and introducing surfactants with good compatibility with the PET matrix, the compatibility between the two phases is greatly improved while retaining its high-efficiency UV protection performance.

[0032] Specifically, in the technical solution of the present invention, in step S101, the surfactant is first complexed with metal ions to regulate the nucleation rate and inhibit the excessive growth of MOF crystals, thereby obtaining small-sized, highly dispersed particles and improving the interfacial compatibility with PET. In step S102, the organic ligands are deprotonated in an alkaline environment to accelerate the coordination reaction and form a MOF with high crystallinity and complete structure. At the same time, the surfactant is coated in situ to form an "active layer" to prevent the MOF from agglomerating or precipitating in subsequent processing.

[0033] In some embodiments, the surfactant includes at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and dodecyltrimethylammonium chloride.

[0034] In some embodiments, the molar ratio of the metal source to the surfactant is 1:0.1 to 1:0.4; it can be 1:0.1, 1:0.2, 1:0.5, 1:1 or 1:5. Within the above ratio range, sufficient surface modification is ensured without hindering MOF lattice formation. If the ratio is too low, the modification will be insufficient, and if it is too high, it may inhibit crystal growth or leave residual impurities.

[0035] The molar ratio of the metal source to the organic ligand is 1:0.5 to 1:4.

[0036] The mixing temperature described in this invention is 60~80℃; and / or, The mixing time is 5-10 min; and / or, The stirring speed includes 800~1200 r / min.

[0037] In one embodiment, the drying temperature includes 80~150°C; within the above drying range and time, the decrease in PET molecular weight or the generation of bubbles due to hydrolysis can be reduced, thus ensuring the performance of the final product.

[0038] In another aspect, this invention proposes the application of UV-protective powders in optical thin films, but it is not limited to this. Specifically, it can be used in packaging films for food, pharmaceuticals, and cosmetics, backsheets for solar cells in outdoor sportswear, and encapsulation films for photovoltaic modules.

[0039] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0040] Experimental materials The PET granules are optical film-grade polyester chips with an intrinsic viscosity of 0.5–0.7 dL / g; Example 1 This embodiment provides a method for preparing a UV-protective powder, including the following steps: 95 parts of PET granules; 3 parts of modified MOF powder; 1 part dispersant; One method for preparing a UV-protective powder includes the following steps: By weight, take 95 parts of PET chips, 3 parts of modified Zn-MOF powder, and 1 part of PEG-4000 dispersant, add them to a high-speed mixer and mix for 10 min (1000 r / min); add the mixture to a twin-screw extruder, set the extrusion temperature range to 260℃ and the screw speed to 250 r / min, extrude the strip material, cut it into pellets after water cooling, and dry it with hot air at 110℃ for 5 h to obtain UV-resistant powder, that is, UV-resistant PET masterbatch.

[0041] A method for preparing modified MOF powder includes the following steps: 20.9 g of sodium dodecylbenzenesulfonate (surfactant) was added to 1000 mL of methanol and stirred at 50 °C for 15 min until dissolved. 110 g of zinc acetate (metal source) was added and stirring was continued for 20 min to form a zinc-surfactant pre-dispersion A, wherein the molar ratio of the metal source to the surfactant was 1:0.1. 70 g of sodium hydroxide and 98.52 g of 2-methylimidazole (organic ligand) were added sequentially to a new 1000 mL of methanol and stirred thoroughly to obtain dispersion B. The volume ratio of A to B was mixed at 1:1 and stirred for 10 min, then transferred to a hydrothermal reactor and reacted at 25 °C for 12 h. After cooling, the mixture was centrifuged (4000 r / min, 12 min). The precipitate was washed four times each with deionized water and anhydrous ethanol, dried under vacuum at 70 °C for 10 h, and ground through a 200-mesh sieve to obtain modified Zn-MOF powder.

[0042] Example 2 The specific components of Example 2 are as follows: 94.7 parts of PET granules; 4 parts of modified MOF powder; 1.3 parts dispersant; A method for preparing a UV-protective powder includes the following steps: By weight, 80 parts of PET chips, 8 parts of modified Zn-MOF powder, and 1 part of PEG-4000 dispersant were mixed in a high-speed mixer for 12 min (900 r / min); the parameters of the twin-screw extruder were the same as in Example 1, and after extrusion and pelletizing, the mixture was dried at 110°C for 6 h to obtain UV-resistant PET masterbatch.

[0043] Preparation of modified MOF powder: The difference between this example and Example 1 is that the sodium dodecylbenzenesulfonate (surfactant) is changed to 41.8 g, wherein the molar ratio of the metal source to the surfactant is 1:0.2, and the rest of the preparation process is the same as in Example 1. Example 3 The specific components of Example 3 are as follows: 93.3 parts of PET granules; 5 parts of modified MOF powder; 1.7 parts dispersant; A method for preparing a UV-protective powder includes the following steps: by weight, take 94 parts of PET chips, 5 parts of modified Zn-MOF powder, and 1 part of PEG-4000 dispersant, mix them in a high-speed mixer for 12 min (900 r / min); the parameters of the twin-screw extruder are the same as in Example 1, and after extrusion and pelletizing, dry at 110°C for 6 h to obtain UV-protective PET masterbatch.

[0044] Preparation of modified MOF powder: The difference between Example 3 and Example 1 is that the sodium dodecylbenzenesulfonate (surfactant) was changed to 83.6 g, wherein the molar ratio of the metal source to the surfactant was 1:0.4, and the rest of the preparation process was the same as in Example 1. Example 4 The specific components of Example 4 are as follows: 92.5 parts of PET granules; 5 parts of modified MOF powder; 2.5 parts dispersant; A method for preparing a UV-protective powder includes the following steps: 92.5 parts of PET chips, 5 parts of modified Zn-MOF powder, and 2.5 parts of dispersant (PEG-4000 and EBS 1:1). The mixing and extrusion parameters are the same as in Example 1 to obtain a UV-protective PET masterbatch. Preparation of modified MOF powder: 43.7 g of cetyltrimethylammonium bromide (cationic surfactant) was added to 1000 mL of methanol and stirred at 50 °C for 20 min; 70 g of sodium hydroxide and 98.52 g of 2-methylimidazole (organic ligand) were added sequentially and mixed thoroughly; then 110 g of zinc acetate (metal source) was added and transferred to a hydrothermal reactor and reacted at 25 °C for 16 h, wherein the molar ratio of the metal source to the surfactant was 1:0.2; the subsequent cleaning, drying and grinding steps were the same as in Example 4 to obtain modified Zn-MOF powder.

[0045] Comparative Example 1 Comparative Example 1 is similar to Example 1 in that its preparation process is similar to that of Example 1. The difference is that, except that the MOF powder is not modified, the other steps are the same as those in Example 1. That is, pure Zn-MOF powder is directly mixed with raw materials such as PET chips and extruded into granules. The preparation steps of the pure Zn-MOF powder include: taking 110 g of zinc acetate (metal source) and adding it to 1000 mL of methanol, stirring at 50 °C for 15 min until dissolved, continuing to stir for 20 min to pre-dispersion A, adding 70 g of sodium hydroxide and 98.52 g of 2-methylimidazole (organic ligand) to a new 1000 mL and stirring thoroughly to obtain dispersion B; mixing and stirring liquids A and B in a 1:1 ratio for 10 min, then transferring to a hydrothermal reactor and reacting at 25 °C for 12 h; after cooling, centrifuging (4000 r / min, 12 min), washing the precipitate with deionized water and anhydrous ethanol 4 times each, vacuum drying at 70 °C for 10 h, and grinding through a 200-mesh sieve to obtain Zn-MOF powder.

[0046] Comparative Example 2 Comparative Example 2 is similar to Example 1, except that the method for preparing the modified MOF powder includes the following steps: 110 g of zinc acetate (metal source) was added to 1000 mL of methanol and stirred at 50 °C for 15 min until dissolved. Stirring was continued for 20 min to obtain pre-dispersion A. 70 g of sodium hydroxide and 98.52 g of 2-methylimidazole (organic ligand) were added sequentially to a new 1000 mL of methanol and stirred thoroughly to obtain dispersion B. Dispersions A and B were mixed in a 1:1 volume ratio and stirred for 10 min, then transferred to a hydrothermal reactor and reacted at 25 °C for 12 h. Next, 20.9 g of sodium dodecylbenzenesulfonate (surfactant) was added to the hydrothermal reactor and reacted at 25 °C for 3 h. After cooling, the mixture was centrifuged (4000 r / min, 12 min). The precipitate was washed four times each with deionized water and anhydrous ethanol, dried under vacuum at 70 °C for 10 h, and ground through a 200-mesh sieve to obtain post-modified Zn-MOF powder. Performance testing Performance testing methods: UV protection and transmittance were measured using a UV-Vis spectrophotometer; tensile strength was measured according to GB / T 1040.2-2006; yellowing index was measured according to GB / T 2409-1980. The test results are shown in Table 1.

[0047] The novel UV-resistant PET masterbatch, i.e. UV-resistant powder, prepared in each embodiment was melt-blended with optical film-grade PET chips (intrinsic viscosity 0.65 dL / g) at a mass ratio of 10%. After extrusion molding, a film sample with a thickness of 80 μm was prepared by biaxial stretching process. The UV resistance performance of the film was specifically tested and characterized by a UV spectrophotometer.

[0048] Table 1

[0049] The test results are shown in Table 1. It can be seen that the effect of the molar ratio of metal ions to surfactant is as follows: In Examples 1-4, as the molar ratio increased from 1:0.1 to 1:0.4, the UV protection rate increased from 99.0% to 99.6%, the tensile strength increased from 186.3 MPa to 190.8 MPa, and the yellowing index decreased from 1.3 to 1.0. After the molar ratio exceeded 1:0.4 (Example 3), the increase in UV protection rate and tensile strength slowed down, but the light transmittance decreased significantly due to particle scattering (from 87.5% to 86.8%). The reason is that when the molar ratio is below 1:0.2, the MOF surface modification is insufficient, and the compatibility and dispersibility are inadequate. When the molar ratio is above 1:0.2, excessive surfactant residue blocks the MOF pores, reducing UV absorption efficiency and increasing optical scattering. Therefore, the optimal molar ratio of metal ions to surfactant is 1:0.2.

[0050] Example 4, by changing the order of surfactant addition—premixing the cationic surfactant with the organic ligand before adding the metal salt to synthesize the modified MOF—results in a larger final MOF particle size compared to other examples (generally greater than 1.5 μm). This significantly reduces light transmittance due to particle scattering, but the UV protection effect remains consistent with other examples due to the effect of the MOF crystals. Therefore, the optimal order of adding the modified MOF pair is to first mix the surfactant with the metal salt solution, and then mix it with the organic ligand.

[0051] The present invention has significant advantages in UV protection stability (yellowing index and mechanical properties); compared with Comparative Example 1 (unmodified MOF), the compatibility and dispersibility (transmittance) of the present invention are greatly improved, verifying the necessity of surfactant pre-binding modification.

[0052] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A UV-protective powder, characterized in that, The components include the following parts by weight: 80-95 parts of PET matrix; 3 to 8 parts of modified MOF powder; 1-3 parts dispersant; The modified MOF powder includes a porous crystal framework and at least a surfactant adsorbed on the porous crystal framework. The porous crystal framework is formed by the self-assembly of a metal source and an organic ligand through coordination bonds.

2. The UV-protective powder as described in claim 1, characterized in that, The specific surface area of ​​the porous crystal framework is 400–1800 m² / g; and / or, The pore size distribution of the porous crystal framework is concentrated in the range of 0.5–2.0 nm; and / or, The modified MOF powder has a D10 of less than 0.5 μm, a D50 of less than 0.8 μm, and a D90 of less than 1.2 μm.

3. The UV-protective powder as described in claim 1, characterized in that, The PET matrix includes PET particles or PET chips; and / or, The metal source includes at least one selected from aluminum nitrate, aluminum sulfate, zinc nitrate, zinc acetate, cerium nitrate, magnesium nitrate, and copper sulfate; and / or, The organic ligand comprises at least one of fumaric acid, terephthalic acid, and 2-methylimidazole; and / or The dispersant includes at least one of polyethylene glycol, stearamide, and vinyl bis-stearamide.

4. A method for preparing the UV-protective powder as described in claim 1, characterized in that, The preparation method includes the following steps: S10. Mix and stir the PET matrix, modified MOF powder and dispersant to obtain the first mixture; S20. The first mixture is extruded and granulated to obtain the second mixture; S30. The second mixture is cut and dried to obtain a UV-resistant powder.

5. The method for preparing the UV-protective powder as described in claim 1, characterized in that, The method for preparing the modified MOF powder includes: S101. Mix the surfactant with the metal source to obtain a pre-dispersion; S102. The pre-dispersed liquid is mixed with the organic ligand under alkaline conditions to obtain modified MOF powder.

6. The method for preparing the UV-protective powder as described in claim 5, characterized in that, The surfactant includes at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and dodecyltrimethylammonium chloride.

7. The method for preparing the UV-protective powder as described in claim 5, characterized in that, The molar ratio of the metal source to the surfactant is 1:0.1 to 1:0.4; and / or, The molar ratio of the metal source to the organic ligand is 1:0.5 to 1:

4.

8. The method for preparing the UV-protective powder as described in claim 4, characterized in that, The mixing temperature is 60~80℃; and / or, The mixing time is 5-10 min; and / or, The stirring speed includes 800~1200 r / min.

9. The method for preparing the UV-protective powder as described in claim 4, characterized in that, The drying temperature is 80~150℃; and / or, The drying time is 2 to 6 hours.

10. The application of the UV-protective powder as described in any one of claims 1-3 or the UV-protective powder as described in any one of claims 4-9, characterized in that, Used in optical thin films.

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