Anti-ultraviolet PMMA-based composite material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer materials, and discloses an anti-ultraviolet PMMA-based composite material as well as a preparation method and application thereof. The anti-ultraviolet PMMA-based composite material is prepared from the following components in parts by weight: 100 parts of polymethyl methacrylate, 1 to 5 parts of an anti-ultraviolet agent, 5 to 10 parts of a toughening agent, 0.5 to 5 parts of a bulking agent, 0.3 to 1 part of an antioxidant and 1 to 5 parts of a lubricating agent, the melt volume rate of the polymethyl methacrylate is 3cm < 3 > / 10min, and the density of the polymethyl methacrylate is 1.19 g / cm < 3 >. The composite material has excellent anti-ultraviolet performance, weather resistance and good mechanical performance, is especially suitable for preparing an anti-ultraviolet PMMA-based composite film or a car lamp lampshade, can keep the anti-ultraviolet performance and the mechanical performance for a long time in an outdoor or high-ultraviolet environment, and prolongs the service life of a product.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to an ultraviolet-resistant PMMA-based composite material, a preparation method thereof, and an application thereof. Background Art

[0002] The headlight cover is an important part of the entire vehicle headlight. In addition to controlling the refraction and reflection of the light source, it also plays a role in sealing and protecting the lens, electronic components, and circuit board inside the headlight. Long-term exposure to ultraviolet light will cause adverse phenomena such as yellowing of the surface of the headlight cover, reduction in transparency, and decrease in hardness, which will affect the normal use of the headlight function and ultimately have an adverse impact on driving safety. PMMA is a common polymer material suitable for headlight covers. At present, the main method for improving the ultraviolet resistance of PMMA is to add ultraviolet absorbers. The ultraviolet absorber can absorb ultraviolet light in a certain wavelength range, effectively protect the PMMA material from ultraviolet damage, and at the same time maintain a high light transmittance.

[0003] However, the existing ultraviolet absorbers have the following disadvantages:

[0004] (1). High cost. The existing ultraviolet absorbers, such as metal oxide nanoparticles, especially high-purity nanoparticles, such as titanium dioxide (TiO 2 ), zinc oxide (ZnO), have high production costs and are expensive;

[0005] (2). The existing ultraviolet absorbers (such as benzotriazoles and benzophenones) are of low toxicity and harmful to the environment. The benzene-containing ultraviolet absorbers are not only harmful to the human body but also cause environmental pollution;

[0006] (3). Insufficient stability. The existing ultraviolet absorbers (organic ultraviolet absorbers, such as phenyl salicylate) may migrate and precipitate from the PMMA material after long-term use, resulting in a decline in material performance and requiring regular replacement or re-treatment.

[0007] Therefore, the PMMA-based composite material added with the above ultraviolet absorber has poor ultraviolet resistance, is easily aged under ultraviolet irradiation, and will cause a decline in the mechanical properties of the material after aging, affecting normal use. Summary of the Invention

[0008] The technical problem to be solved by the present invention is: to overcome the deficiencies in the prior art and provide an ultraviolet-resistant PMMA-based composite material, a preparation method thereof, and an application thereof. The PMMA headlight cover prepared by the present invention through melting and blending an ultraviolet absorber and a toughening agent has good ultraviolet resistance, a simple process, low cost, and is environmentally friendly.

[0009] The technical solution adopted by the present invention to solve its technical problems is:

[0010] An anti-ultraviolet PMMA-based composite material, by weight, comprises the following components:

[0011]

[0012] The melt volume rate of the polymethyl methacrylate (PMMA) is 3 cm 3 / 10 min (230 °C / 3.8 kg), and the density is 1.19 g / cm 3 .

[0013] As the matrix material, PMMA has excellent optical transparency, weather resistance and mechanical strength. Its specific ranges of melt volume rate and density (3 cm 3 / 10 min (230 °C / 3.8 kg), density 1.19 g / cm 3 ) ensure the fluidity and formability of the material during processing, while ensuring the mechanical properties and optical properties of the final product.

[0014] Further, the anti-ultraviolet agent is modified tannic acid, and the preparation method of the modified tannic acid is as follows:

[0015] Dissolve the silane coupling agent in an acidic solution for hydrolysis. The pH value of the acidic solution is 4.5 - 6.5. Stir until transparent to obtain a silane coupling agent solution. Mix the silane coupling agent solution with tannic acid to obtain a mixed solution. Adjust the mixed solution to weakly alkaline. The pH value of the mixed solution is 8 - 10. Continue stirring, let it stand for stratification, remove the supernatant, filter, wash and dry to obtain modified tannic acid;

[0016] The mass of the silane coupling agent is 0.2 - 5% of the mass of tannic acid;

[0017] The stirring temperature of the mixed solution is 25 - 50 °C, and the stirring time is 8 - 50 h.

[0018] As an anti-ultraviolet agent, modified tannic acid can effectively absorb ultraviolet rays, preventing the PMMA material from yellowing, degrading or decreasing mechanical properties under ultraviolet light irradiation. Through the modification with silane coupling agent, the compatibility between tannic acid and the PMMA matrix is improved, enhancing the dispersibility and stability of the anti-ultraviolet agent, thereby prolonging the service life of the material.

[0019] Further, the silane coupling agent can be one of KH550, KH560 and KH570.

[0020] Further, the toughening agent is an ethylene-methyl acrylate-glycidyl methacrylate random terpolymer. The content of methyl acrylate in the terpolymer is 23 - 26 wt%, and the content of glycidyl methacrylate is 8 wt%.

[0021] The addition of the toughening agent significantly improves the impact resistance and toughness of the PMMA material, avoiding brittle fracture of the material when subjected to external forces. The contents of methyl acrylate and glycidyl methacrylate in the terpolymer optimize the compatibility between the toughening agent and the PMMA matrix, further enhancing the comprehensive mechanical properties of the material.

[0022] Furthermore, the compatibilizer is a styrene-acrylate copolymer containing epoxy groups, with a molecular weight of 2500 - 7500. The compatibilizer can improve the interfacial compatibility between the components, promote the uniform dispersion of additives such as the ultraviolet absorber and the toughening agent in the PMMA matrix, and avoid the phenomenon of phase separation. Its epoxy groups have good reactivity with the PMMA matrix, further enhancing the interfacial bonding force of the material and improving the overall properties of the composite material.

[0023] Furthermore, the antioxidant is a compound of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite, and the weight ratio of the two is 1:1. The addition of the antioxidant effectively inhibits the degradation reaction caused by thermal oxidation or photooxidation during the processing and use of the material. The compound use of the two antioxidants exerts a synergistic effect, which can both capture free radicals and decompose peroxides, significantly improving the thermal stability and aging resistance of the material.

[0024] Furthermore, the lubricant is at least one of stearic acid amide, pentaerythritol stearate, and methyl silicone oil. The lubricant improves the processing fluidity of the material, reduces the heat generated by friction during the processing, and prevents the material from undergoing thermal degradation during extrusion or injection molding. At the same time, the addition of the lubricant also improves the surface smoothness and demolding performance of the material, which is beneficial to the preparation of high-quality products.

[0025] A preparation method of the above-mentioned ultraviolet-resistant PMMA-based composite material specifically includes the following steps:

[0026] Step S1: Place polymethyl methacrylate, the ultraviolet absorber, the toughening agent, and the compatibilizer in an oven and dry them for 12 hours, then put them into an aluminum foil bag and seal for standby; this step can ensure that each component is fully dried before processing, avoiding the adverse effects of moisture on the material properties;

[0027] Step S2: Weigh the raw materials in step S1 according to the weight parts, and then put them into a high-speed mixer for premixing for 15 - 30 minutes to obtain a premix; high-speed mixing can make each component uniformly dispersed, avoiding too high or too low local concentration and improving the uniformity of the material;

[0028] Step S3: Pour the premix in Step S2 into a twin-screw extruder through a barrel. The twin-screw extruder is divided into a preheating section, a shearing section, and a mixing section. After being extruded by the twin-screw, it is then cooled, dried, and pelletized to obtain the ultraviolet-resistant PMMA-based composite material;

[0029] Further, in Step S3, the range of the screw processing temperature is 180 - 250 °C, and the screw rotation speed is 60 - 80 rpm. By controlling the temperature (180 - 250 °C) and the screw rotation speed (60 - 80 rpm) in sections, efficient melting, shearing, and mixing of the material are achieved, ensuring the uniformity and performance stability of the composite material.

[0030] An application of the ultraviolet-resistant PMMA-based composite material as described above is used to prepare an ultraviolet-resistant PMMA-based composite film or an ultraviolet-resistant PMMA-based headlight cover.

[0031] For the ultraviolet-resistant PMMA-based composite film, after hot-pressing the ultraviolet-resistant PMMA-based composite material into a film, it is used for performance testing, where the hot-pressing temperature is 250 °C and the pressure is 10 MPa.

[0032] For the ultraviolet-resistant PMMA-based headlight cover, the ultraviolet-resistant PMMA-based composite material is added to an injection molding machine, melted and processed, and then cooled and formed to obtain the ultraviolet-resistant PMMA-based headlight cover, where the injection molding temperature is 190 - 260 °C and the injection molding pressure is 10 - 20 MPa.

[0033] The beneficial effects of the present invention are as follows: The present invention is reasonably designed and the preparation method is simple, having the following advantages:

[0034] (1) The composite material of the present invention has excellent ultraviolet resistance, weather resistance, and good mechanical properties, and is particularly suitable for preparing an ultraviolet-resistant PMMA-based composite film or a headlight cover. In outdoor or high-ultraviolet environments, the composite material can maintain its ultraviolet resistance and mechanical properties for a long time, extending the service life of the product;

[0035] (2) The composite material of the present invention is used to prepare an ultraviolet-resistant PMMA-based composite film or a headlight cover, reducing the manufacturing process difficulty, improving the production efficiency, and reducing the production cost. Detailed Embodiments

[0036] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms also include the plural forms. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0039] An anti-ultraviolet PMMA-based composite material, by weight, comprises the following components:

[0040]

[0041] The melt volume rate of polymethyl methacrylate is 3 cm 3 / 10 min (230 °C / 3.8 kg), and the density is 1.19 g / cm 3 .

[0042] The anti-ultraviolet agent is modified tannic acid, and the preparation method is as follows:

[0043] Dissolve the silane coupling agent in an acidic solution for hydrolysis. The pH value of the acidic solution is 4.5 - 6.5. Stir until transparent to obtain a silane coupling agent solution. Mix the silane coupling agent solution with tannic acid to obtain a mixed solution. Adjust the mixed solution to weakly alkaline, and the pH value of the mixed solution is 8 - 10. Continue to stir, let it stand for stratification, remove the supernatant, filter, wash, and dry to obtain modified tannic acid; the mass of the silane coupling agent is 0.2 - 5% of the mass of tannic acid; the stirring temperature of the mixed solution is 25 - 50 °C, and the stirring time is 8 - 50 h.

[0044] The silane coupling agent can be one of KH550, KH560, and KH570.

[0045] The toughening agent is an ethylene-methyl acrylate-glycidyl methacrylate random terpolymer. The content of methyl acrylate in the terpolymer is 23 - 26 wt%, and the content of glycidyl methacrylate is 8 wt%.

[0046] The compatibilizer is a styrene-acrylate copolymer containing an epoxy group, and the molecular weight is 2500 - 7500.

[0047] The antioxidant is a compound of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite, and the weight ratio of the two is 1:1.

[0048] The lubricant is at least one of stearic acid amide, pentaerythritol stearate and methyl silicone oil.

[0049] A preparation method of the anti-ultraviolet PMMA-based composite material as described above specifically includes the following steps:

[0050] Step S1: Place polymethyl methacrylate, anti-ultraviolet agent, toughening agent, and compatibilizer in an oven and dry for 12 hours, then put them into an aluminum foil bag and seal for standby;

[0051] Step S2: Weigh the raw materials in Step S1 according to the weight parts, and then put them into a high-speed mixer for premixing for 15 - 30 minutes to obtain a premix;

[0052] Step S3: Pour the premix in Step S2 into a twin-screw extruder through a barrel. The twin-screw extruder is divided into a preheating section, a shearing section, and a mixing section. After twin-screw extrusion, it is cooled, dried, and pelletized to obtain the anti-ultraviolet PMMA-based composite material;

[0053] In Step S3, the range of the screw processing temperature is 180 - 250 °C, and the screw speed is 60 - 80 rpm.

[0054] Example 1

[0055] A preparation method of an anti-ultraviolet PMMA-based headlight lamp cover is as follows:

[0056] Place 100 parts of polymethyl methacrylate, 5 parts of toughening agent, and 1 part of anti-ultraviolet agent in an oven at 90 - 110 °C and dry for 4 hours, then put them into an aluminum foil bag and seal for standby; Add 1 part of compatibilizer, 0.3 part of antioxidant, and 3 parts of lubricant together with 100 parts of dried polymethyl methacrylate, 5 parts of toughening agent, and 1 part of anti-ultraviolet agent into a high-speed mixer for premixing for 15 min to obtain a premix; Add the premix into the hopper of a twin-screw extruder, and after passing through the preheating section, shearing section, and mixing section, melt and extrude, with the corresponding temperatures being 190 °C, 240 °C, and 220 °C respectively, and the screw speed being 80 rpm. Finally, after cooling, drying, and pelletizing, obtain the PMMA-based composite material; Thermally press the PMMA-based composite material into a film for performance testing, where the thermal pressing temperature is 250 °C and the pressure is 10 Mpa; Finally, add the PMMA-based composite material into an injection molding machine, melt and process it, and then cool and form to obtain the anti-ultraviolet PMMA-based headlight lamp cover, where the injection molding temperature is 255 °C and the injection molding pressure is 15 MPa.

[0057] In this embodiment: The toughening agent is an ethylene-methyl acrylate-glycidyl methacrylate random terpolymer, with the content of methyl acrylate in the terpolymer being 23 wt% and the content of glycidyl methacrylate being 8 wt%; the ultraviolet absorber is tannic acid modified by a silane coupling agent; the compatibilizer is a styrene-acrylate copolymer containing epoxy groups, with a molecular weight of 6000; the antioxidant is a compound of pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and tris [2,4-di-tert-butylphenyl] phosphite used in a 1:1 ratio; the lubricant is stearic acid amide.

[0058] Example 2

[0059] A preparation method of an ultraviolet-resistant PMMA-based headlight cover is as follows:

[0060] Place 100 parts of polymethyl methacrylate, 5 parts of toughening agent, and 2 parts of ultraviolet absorber in an oven at 90 - 110 °C for 4 hours, then put them into an aluminum foil bag and seal for standby; add 1 part of compatibilizer, 0.3 part of antioxidant, and 3 parts of lubricant together with the dried 100 parts of polymethyl methacrylate, 5 parts of toughening agent, and 2 parts of ultraviolet absorber into a high-speed mixer for premixing for 15 min to obtain a premix; add the premix into the hopper of a twin-screw extruder, and after passing through the preheating section, shearing section, and mixing section, melt and extrude, with the corresponding temperatures being 190 °C, 240 °C, and 220 °C respectively, and the screw speed being 80 rpm. Finally, after cooling, drying, and pelletizing, a PMMA-based composite material is obtained; hot-press the PMMA-based composite material into a film for performance testing, where the hot-pressing temperature is 250 °C and the pressure is 10 Mpa; finally, add the PMMA-based composite material into an injection molding machine for melting and processing, and then cool and form to obtain an ultraviolet-resistant PMMA-based headlight cover, where the injection molding temperature is 255 °C and the injection molding pressure is 15 MPa.

[0061] In this embodiment: The toughening agent is an ethylene-methyl acrylate-glycidyl methacrylate random terpolymer, with the content of methyl acrylate in the terpolymer being 24 wt% and the content of glycidyl methacrylate being 8 wt%; the ultraviolet absorber is tannic acid modified by a silane coupling agent; the compatibilizer is a styrene-acrylate copolymer containing epoxy groups, with a molecular weight of 2500; the antioxidant is a compound of pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and tris [2,4-di-tert-butylphenyl] phosphite used in a 1:1 ratio; the lubricant is stearic acid amide.

[0062] Example 3

[0063] A preparation method of an ultraviolet-resistant PMMA-based headlight cover is as follows:

[0064] Put 100 parts of polymethyl methacrylate, 5 parts of toughening agent, and 3 parts of ultraviolet absorber in an oven at 90 - 110 °C for drying for 4 hours, then put them into an aluminum foil bag and seal for standby; add 1 part of compatibilizer, 0.3 part of antioxidant, 3 parts of lubricant and the dried 100 parts of polymethyl methacrylate, 5 parts of toughening agent and 3 parts of ultraviolet absorber into a high-speed mixer for premixing for 15 min to obtain a premix; put the premix into the hopper of a twin-screw extruder, and after passing through the preheating section, shearing section and mixing section, melt and extrude, with the corresponding temperatures being 190 °C, 240 °C, 220 °C respectively, and the screw speed being 80 rpm. Finally, after cooling, drying and pelletizing, a PMMA-based composite material is obtained; hot-press the PMMA-based composite material into a film for performance testing, where the hot-pressing temperature is 250 °C and the pressure is 10 Mpa; finally, add the PMMA-based composite material into an injection molding machine for melting and processing, and then cool and form to obtain an ultraviolet-resistant PMMA-based headlight cover, where the injection molding temperature is 255 °C and the injection molding pressure is 15 MPa.

[0065] In this example: The toughening agent uses an ethylene-methyl acrylate-glycidyl methacrylate random terpolymer, the content of methyl acrylate in the terpolymer is 25 wt%, and the content of glycidyl methacrylate is 8 wt%; the ultraviolet absorber uses tannic acid modified by a silane coupling agent; the compatibilizer uses a styrene-acrylate copolymer containing an epoxy group with a molecular weight of 3500; the antioxidant uses pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris[2,4-di-tert-butylphenyl] phosphite compounded in a ratio of 1:1; the lubricant uses methyl silicone oil.

[0066] Example 4

[0067] A preparation method of an ultraviolet-resistant PMMA-based headlight cover, the specific method is as follows:

[0068] Put 100 parts of polymethyl methacrylate, 5 parts of toughening agent, and 3 parts of ultraviolet absorber in an oven at 90 - 110 °C for drying for 4 hours, then put them into an aluminum foil bag and seal for standby; add 0.75 part of compatibilizer, 0.3 part of antioxidant, 3 parts of lubricant and the dried 100 parts of polymethyl methacrylate, 5 parts of toughening agent and 3 parts of ultraviolet absorber into a high-speed mixer for premixing for 15 min to obtain a premix; put the premix into the hopper of a twin-screw extruder, and after passing through the preheating section, shearing section and mixing section, melt and extrude, with the corresponding temperatures being 190 °C, 240 °C, 220 °C respectively, and the screw speed being 80 rpm. Finally, after cooling, drying and pelletizing, a PMMA-based composite material is obtained; hot-press the PMMA-based composite material into a film for performance testing, where the hot-pressing temperature is 250 °C and the pressure is 10 Mpa; finally, add the PMMA-based composite material into an injection molding machine for melting and processing, and then cool and form to obtain an ultraviolet-resistant PMMA-based headlight cover, where the injection molding temperature is 255 °C and the injection molding pressure is 15 MPa.

[0069] In this embodiment: The toughening agent is an ethylene-methyl acrylate-glycidyl methacrylate random terpolymer, the content of methyl acrylate in the terpolymer is 26 wt%, and the content of glycidyl methacrylate is 8 wt%; the ultraviolet light absorber is tannic acid modified by a silane coupling agent; the compatibilizer is a styrene-acrylate copolymer containing an epoxy group with a molecular weight of 7500; the antioxidant is a compound of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite used in a 1:1 ratio; the lubricant is pentaerythritol stearate.

[0070] Comparative Example 1

[0071] A preparation method of a PMMA-based headlight lens is as follows:

[0072] 100 parts of polymethyl methacrylate and 5 parts of toughening agent are placed in an oven at 90-110°C for 4 hours and then sealed in an aluminum foil bag for standby; 0.3 part of antioxidant and 3 parts of lubricant are added to 100 parts of dried polymethyl methacrylate and 5 parts of toughening agent in a high-speed mixer and premixed for 15 min to obtain a premix; the premix is added to the hopper of a twin-screw extruder, melted and extruded after passing through a preheating section, a shearing section and a mixing section, and the corresponding temperatures are 190°C, 240°C, 220°C respectively, the screw speed is 80 rpm, and finally it is cooled, dried and pelletized to obtain a PMMA-based composite material; the PMMA-based composite material is hot-pressed into a film for performance testing, where the hot-pressing temperature is 250°C and the pressure is 10 Mpa; finally, the PMMA-based composite material is added to an injection molding machine, melted and processed and then cooled and molded to obtain an ultraviolet-resistant PMMA-based headlight lens, where the injection molding temperature is 255°C and the injection molding pressure is 15 MPa.

[0073] Comparative Example 2

[0074] A preparation method of a PMMA-based headlight lens is as follows:

[0075] 100 parts of polymethyl methacrylate, 5 parts of toughening agent, and 1 part of ultraviolet absorber were placed in an oven at 90 - 110 °C and dried for 4 hours, then sealed in an aluminum foil bag for later use. 0.3 part of antioxidant and 3 parts of lubricant were added to the dried 100 parts of polymethyl methacrylate, 5 parts of toughening agent, and 1 part of ultraviolet absorber in a high - speed mixer and premixed for 15 min to obtain a premix. The premix was added to the hopper of a twin - screw extruder and melt - extruded after passing through the preheating section, shearing section, and mixing section, with corresponding temperatures of 190 °C, 240 °C, and 220 °C, and the screw speed was 80 rpm. Finally, it was cooled, dried, and pelletized to obtain a PMMA - based composite material. The PMMA - based composite material was hot - pressed into a film for performance testing, where the hot - pressing temperature was 250 °C and the pressure was 10 Mpa. Finally, the PMMA - based composite material was added to an injection molding machine, melt - processed, and then cooled and molded to obtain an ultraviolet - resistant PMMA - based headlight cover, where the injection molding temperature was 255 °C and the injection molding pressure was 15 MPa.

[0076] Comparative Example 3

[0077] A preparation method of a PMMA - based headlight cover is as follows:

[0078] 100 parts of polymethyl methacrylate, 5 parts of toughening agent, and 3 parts of ultraviolet absorber were placed in an oven at 90 - 110 °C and dried for 4 hours, then sealed in an aluminum foil bag for later use. 0.3 part of antioxidant and 3 parts of lubricant were added to the dried 100 parts of polymethyl methacrylate, 5 parts of toughening agent, and 3 parts of ultraviolet absorber in a high - speed mixer and premixed for 15 min to obtain a premix. The premix was added to the hopper of a twin - screw extruder and melt - extruded after passing through the preheating section, shearing section, and mixing section, with corresponding temperatures of 190 °C, 240 °C, and 220 °C, and the screw speed was 80 rpm. Finally, it was cooled, dried, and pelletized to obtain a PMMA - based composite material. The PMMA - based composite material was hot - pressed into a film for performance testing, where the hot - pressing temperature was 250 °C and the pressure was 10 Mpa. Finally, the PMMA - based composite material was added to an injection molding machine, melt - processed, and then cooled and molded to obtain an ultraviolet - resistant PMMA - based headlight cover, where the injection molding temperature was 255 °C and the injection molding pressure was 15 MPa.

[0079] The component weight parts of Examples 1 - 4 and Comparative Examples 1 - 3 are specifically shown in Table 1.

[0080] Table 1 Component weight parts of Examples 1 - 4 and Comparative Examples 1 - 3

[0081] Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 Example 4 PMMA 100 100 100 100 100 100 100 UV absorber 0 1 3 1 2 3 3 Toughening agent 5 5 5 5 5 5 5 Compatibilizer 0 0 0 1 1 1 0.75 Antioxidant 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Lubricant 2 2 2 2 2 2 2

[0082] The performance tests of the composite films prepared in Examples 1 - 4 and Comparative Examples 1 - 3 were carried out, and the test results are shown in Table 2.

[0083] Table 2 Test Results of Examples 1 - 4 and Comparative Examples 1 - 3

[0084]

[0085] As can be seen from Table 2, after adding ultraviolet stabilizers in Comparative Examples 1 and 2, the ultraviolet resistance of the PMMA - based composite materials is improved; combined with Comparative Example 3, when the weight fraction of the ultraviolet stabilizer is further increased, the improvement in the ultraviolet resistance of PMMA is small, while the mechanical properties further decline.

[0086] In Examples 1 - 3, while adding ultraviolet stabilizers, small - molecule compatibilizers are added, which not only significantly improves the ultraviolet resistance of PMMA materials, but also improves the mechanical properties of the materials; in Example 4, the weight fraction of the compatibilizer is further optimized, which can improve the mechanical properties and ultraviolet resistance of PMMA materials.

[0087] In summary, the design of the present invention is reasonable, and the preparation method is simple, having the following advantages:

[0088] (1) The composite materials of the present invention have excellent ultraviolet resistance, weather resistance and good mechanical properties, and are particularly suitable for preparing ultraviolet - resistant PMMA - based composite films or headlight lamp covers. In outdoor or high - ultraviolet environments, the composite materials can maintain ultraviolet resistance and mechanical properties for a long time, extending the service life of the products;

[0089] (2) The composite materials of the present invention are used to prepare ultraviolet - resistant PMMA - based composite films or headlight lamp covers, reducing the manufacturing process difficulty, improving the production efficiency and reducing the production cost.

[0090] Finally, it should be noted that: the above - mentioned embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An anti-ultraviolet PMMA-based composite material, characterized in that: By weight, it includes the following components: The melt volume rate of the polymethyl methacrylate is 3 cm 3 / 10min, density is 1.19g / cm 3 .

2. The UV-resistant PMMA-based composite material according to claim 1, characterized in that: The anti-ultraviolet agent is modified tannic acid, and the preparation method of the modified tannic acid is as follows: The silane coupling agent is dissolved in an acidic solution for hydrolysis, wherein the pH value of the acidic solution is 4.5 to 6.5, and stirred until transparent to obtain a silane coupling agent solution, the silane coupling agent solution is mixed with tannic acid to obtain a mixed solution, the mixed solution is adjusted to be weakly alkaline, wherein the pH value of the mixed solution is 8 to 10, the stirring is continued, the mixture is allowed to stand for stratification, the supernatant is removed, and the mixture is filtered, washed, and dried to obtain modified tannic acid; The mass of the silane coupling agent is 0.2-5% of the mass of the tannic acid; The stirring temperature of the mixed solution is 25-50° C., and the stirring time is 8-50 hours.

3. The UV-resistant PMMA-based composite material according to claim 2, characterized in that: The silane coupling agent may be one of KH550, KH560 and KH570.

4. The UV-resistant PMMA-based composite material according to claim 1, characterized in that: The toughening agent is a random terpolymer of ethylene-methyl acrylate-glycidyl methacrylate, wherein the content of methyl acrylate in the terpolymer is 23-26 wt %, and the content of glycidyl methacrylate is 8 wt %.

5. The UV-resistant PMMA-based composite material according to claim 1, characterized in that: The compatibilizer is a styrene-acrylate copolymer containing epoxy groups, and the molecular weight is 2500-7500.

6. The UV-resistant PMMA-based composite material according to claim 1, characterized in that: The antioxidant is a compound of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester and tris[2,4-di-tert-butylphenyl] phosphite, and the weight ratio of the two is 1:

1.

7. The UV-resistant PMMA-based composite material according to claim 1, characterized in that: The lubricant is at least one of stearic acid amide, pentaerythritol stearate and methyl silicone oil.

8. A method for preparing the UV-resistant PMMA-based composite material according to any one of claims 1 to 7, characterized in that: The specific steps include: Step S1: placing polymethyl methacrylate, anti-ultraviolet agent, toughening agent and compatibilizer in an oven and drying for 12 hours, and then placing in an aluminum foil bag and sealing for later use; Step S2: weighing the raw materials in step S1 according to weight, and then putting them into a high-speed mixer for premixing for 15 to 30 minutes to obtain a premix; Step S3: pouring the premix in step S2 into a twin-screw extruder through a barrel. The twin-screw extruder is divided into a preheating section, a shearing section and a mixing section. After the twin-screw extrusion, the premix is ​​cooled, dried and pelletized to obtain an anti-ultraviolet PMMA-based composite material.

9. The UV-resistant PMMA-based composite material according to claim 1, characterized in that: In step S3, the screw processing temperature ranges from 180 to 250° C., and the screw speed ranges from 60 to 80 rpm.

10. An application of the UV-resistant PMMA-based composite material according to any one of claims 1 to 7, characterized in that: Used for preparing UV-resistant PMMA-based composite films or UV-resistant PMMA-based car lamp covers.

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