Preparation method of regenerated PMMA (polymethyl methacrylate) material based on waste car lamp plastic

Abstract

The invention relates to the technical field of preparation of polymethyl methacrylate, and particularly discloses a preparation method of a regenerated PMMA (polymethyl methacrylate) material based on waste car lamp plastics, which comprises the following steps: (1) blending waste PMMA particles, nano silicon dioxide, a modified silane coupling agent, a flexibilizer, a lubricant, an antioxidant and an antistatic agent under the protection of nitrogen to obtain a blend; and (2) under the protection of nitrogen, melting the blended material obtained in the step (1) through a screw extruder, and extruding and granulating to obtain the composite material. The regenerated PMMA material based on the waste car lamp plastic prepared by the method has excellent properties, such as flame retardant property, anti-ultraviolet property, mechanical property and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of polymethyl methacrylate material preparation, and particularly to a method for preparing recycled PMMA material based on waste headlight plastics. Background Art

[0002] Polymethyl methacrylate (PMMA), also known as plexiglass, is an important transparent organic material. It has many excellent properties, such as high transparency, suitable refractive index, good tensile strength and impact toughness, etc. These properties make it widely used in many fields such as agriculture, aviation, construction and optical instruments. However, PMMA materials still have some deficiencies, such as poor heat resistance, flame retardant performance and anti-aging performance. These limitations not only make the materials vulnerable to influence during production and processing, but also limit the application scope of PMMA materials.

[0003] Chinese Patent with application number CN201811507029.3 provides a PMMA composite material and its preparation method. The PMMA composite material is composed of raw materials in the following weight percentages: 50 - 83% of a blend of polymethyl methacrylate and polybutylene terephthalate, 5 - 33% of nano aluminum hydroxide or modified nano aluminum hydroxide, 0.5 - 3% of antioxidant, and 1 - 25% of toughening agent. The PMMA composite material prepared by this invention exhibits excellent heat resistance, aging resistance and chemical resistance, and at the same time has excellent mechanical strength and high light transmittance. However, there will be compatibility problems between organic substances such as polymethyl methacrylate and polybutylene terephthalate and inorganic substances nano aluminum hydroxide / modified nano aluminum hydroxide in this invention. This kind of compatibility problem will lead to uneven microstructure of the composite material and affect the overall performance of the material. Chinese Patent with application number CN202310068353.4 provides a PMMA composite material and its preparation method. The composition of the PMMA composite material includes, by mass fraction: 70% - 90% of PMMA, 5% - 10% of modified hydroxyapatite, and 5% - 15% of modified montmorillonite. The PMMA composite material of this invention has excellent mechanical properties and flame retardant performance. However, when the modified hydroxyapatite and modified montmorillonite in this invention are mixed with the PMMA matrix, it is not easy to achieve uniform dispersion, and it is extremely easy to form stress concentration points inside the material, weakening the mechanical properties of the composite material, which will limit the use of PMMA composite materials in some application fields.

[0004] Therefore, developing a method for preparing recycled PMMA materials with excellent flame retardant performance, ultraviolet resistance, high temperature resistance and mechanical properties from waste headlight plastics is of great significance for promoting the wide application of PMMA materials. Summary of the Invention

[0005] To solve the above problems, the present invention provides a preparation method of recycled PMMA material based on waste headlight plastics. The recycled PMMA material prepared by this method has a variety of excellent properties, such as flame retardancy, ultraviolet resistance, high temperature resistance, etc., enabling it to meet a wide range of application requirements.

[0006] The technical solution adopted by the present invention to achieve the above object is as follows: A preparation method of recycled PMMA material based on waste headlight plastics, comprising the following steps: under nitrogen protection, mixing waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent to obtain a blend; melting and extruding the blend through a screw extruder to form pellets. The preparation method of the modified silane coupling agent is as follows: Step S1: Add silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide to N,N-dimethylformamide under the conditions of 60-80 °C, nitrogen atmosphere, and stirring, react for 4-6 h, cool to room temperature, and purify to obtain an intermediate. Step S2: Add the intermediate obtained in Step S1, aluminum trichloride, and 5-carboxybenzotriazole to N,N-dimethylformamide under the conditions of 100-110 °C and stirring, react for 3-5 h, cool to room temperature, and purify to obtain the modified silane coupling agent. The synthesis route of the modified silane coupling agent is as follows: ; ; Furthermore, the weight ratio of the waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent is 70:5-10:1-5:5-8:1-5:1-3:1-3.

[0007] Furthermore, in Step S1, the molar ratio of the silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide is 1:1.1-1.2:0.1-0.15, and the addition amount of the silane coupling agent KH-560 in N,N-dimethylformamide is 0.05-0.06 g / mL.

[0008] Furthermore, in Step S2, the molar ratio of the intermediate, aluminum trichloride, and 5-carboxybenzotriazole is 1:0.9-1:0.05-0.06, and the addition amount of 5-carboxybenzotriazole in N,N-dimethylformamide is 0.04-0.05 g / mL.

[0009] Furthermore, the toughening agent is one or more of methyl methacrylate-butadiene-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, POE plastic, and GMA plastic.

[0010] Further, the lubricant is one or more of stearamide, calcium stearate, zinc stearate, and pentaerythritol stearate.

[0011] Further, the antioxidant is one or more of antioxidant 300, antioxidant 264, antioxidant 168, antioxidant 618, antioxidant 1010, and antioxidant 1076.

[0012] Further, the antistatic agent is one or more of benzoyl peroxide, diisopropylbenzene peroxide, isocyanate, and sodium dodecylbenzenesulfonate.

[0013] The present invention has the following beneficial effects: The present invention prepares a recycled PMMA material based on waste headlight plastics by means of melt extrusion. The recycled PMMA material is composed of raw materials such as waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, etc. Among them, the modified silane coupling agent is prepared by a chemical modification method. First, a ring-opening reaction occurs between the amino group of diethyl pyrophosphoramide and the epoxy group of silane coupling agent KH-560 to obtain an intermediate, and then an esterification reaction occurs between the hydroxyl group of the intermediate and the carboxyl group of 5-carboxybenzotriazole to obtain the modified silane coupling agent. The molecular structure of the modified silane coupling agent contains silicon, nitrogen, phosphorus elements and triazole groups. The introduction of silicon element helps to improve the heat resistance of the composite material. In a high-temperature environment, the molecular chains of the composite material are prone to situations such as intensified thermal movement and chain segment breakage, resulting in a decline in material performance. However, the Si-C chemical bond can, to a certain extent, restrict the thermal movement of molecular chains. Therefore, the introduction of the modified silane coupling agent can improve the heat resistance of the PMMA material. The introduction of nitrogen element can improve the flame retardancy of the composite material. During the combustion process, the modified silane coupling agent can release non-combustible gases such as nitrogen, dilute the oxygen concentration in the combustion area, reduce the flame propagation rate, and thus slow down the combustion reaction of the PMMA material. Nitrogen-containing compounds can also be added to the composite material as heat stabilizers. When the material is subjected to high temperature, the nitrogen element can capture free radicals and inhibit the thermal degradation reaction of molecular chains. Therefore, the modified silane coupling agent can prevent or delay the decomposition process of the PMMA material at high temperature, enabling the PMMA material to maintain certain physical and chemical properties at a relatively high temperature, such as maintaining the shape and transparency of the material. The introduction of phosphorus element can also play a flame retardant role. Phosphorus-containing compounds can form a dense carbon layer during the combustion process. This carbon layer can insulate heat and oxygen, prevent the transfer of heat and oxygen to the interior of the material, and at the same time can also inhibit the generation and escape of combustible gases, delaying the further combustion or degradation of the material. Therefore, the modified silane coupling agent can effectively improve the flame retardancy of the PMMA material. In addition, silicon, nitrogen, and phosphorus elements can produce a synergistic effect in the PMMA material, jointly improving the flame retardancy of the material. The introduction of triazole groups can improve the ultraviolet resistance of the composite material. Triazole groups can absorb ultraviolet energy and convert the ultraviolet energy into harmless heat energy through electronic transition and emit it, thus avoiding the direct damage of ultraviolet rays to the molecular chains of the PMMA material. Therefore, the modified silane coupling agent can effectively delay the photoaging process of the PMMA material, enabling the PMMA material to maintain transparency and mechanical properties for a long time in a light environment such as outdoors.In addition, the triazole group can also enhance the thermal stability of the material. First, the nitrogen atoms in the triazole group have strong electronegativity and can form hydrogen bonds with functional groups such as carbonyl or hydroxyl groups in the composite material. This hydrogen bond interaction can effectively restrict the movement of molecular chains, reduce the excessive thermal vibration and rotation of molecular chains, thereby reducing the collision and friction between molecular chains, and further reducing the possibility of fracture, improving the thermal stability of the PMMA material. Second, the triazole group has a conjugated structure, enabling π electrons to delocalize within the molecule, forming a relatively stable electron cloud distribution. When the composite material is heated, this conjugated structure can absorb and disperse heat, making the energy distribution inside the material more uniform and avoiding rapid degradation of molecular chains caused by excessive local energy. In addition, the conjugated structure can also interact with the conjugated system of the PMMA molecular chain, further enhancing the conjugation degree of the entire material and improving the stability of the molecular chain, making the PMMA material less likely to break and decompose in a high-temperature environment. Therefore, through the synergistic effect of hydrogen bond interaction and conjugated properties, the triazole group can significantly improve the thermal stability of the PMMA material.

[0014] In the present invention, waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant and other raw materials are compounded to obtain a recycled PMMA material based on waste headlight plastics. The modified silane coupling agent in this material system not only endows the PMMA material with excellent flame retardancy, anti-ultraviolet performance, high-temperature resistance and mechanical properties, but also acts as a "bridge" between organic raw materials such as nano-silica and PMMA particles, thus significantly improving the interfacial compatibility between nano-silica and the PMMA material, making the nano-silica disperse more uniformly in the PMMA matrix and avoiding the occurrence of agglomeration phenomenon, so that the nano-silica can better play its strengthening role. Detailed implementation mode

[0015] Next, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0016] The raw materials used in the following embodiments are all ordinary commercially available products. The particle size of the nano-silica is 30 - 50 nm, purchased from Hangzhou Jikang New Materials Co., Ltd., model number SS-S50; the waste PMMA particles are derived from waste transparent PMMA headlights, obtained by crushing, cleaning and flotation, with a density of 1.19 g / cm 3, the PMMA content is 90%; the methyl methacrylate-butadiene-styrene copolymer is purchased from Shanghai Langqi Plastic Raw Materials Co., Ltd., with the model ZYLAR® 650 and the brand BENLING; the acrylonitrile-butadiene-styrene copolymer is purchased from Shanghai Zhaohe Plasticization Co., Ltd., with the model ABS PA-757 and the brand CHIMEI POLYLAC®; the POE plastic is purchased from Shanghai Oshuo Plastic Co., Ltd., with the model 6102FL and the brand ExxonMobil; the GMA plastic is purchased from Guangdong Dingxin Polymer Technology Co., Ltd., with the model 4170 and the brand DuPont; the antioxidant 300 has the brand JYANOX and the model JYANOX 300; the antioxidant 264 has the brand Panhua and the product number pwf-bht-r; the antioxidant 168 has the brand Jiyi Chemical Industry and the model JYANOX 168; the antioxidant 618 has the brand Panhua and the product number pwf618; the antioxidant 1010 has the brand Jiyi; the antioxidant 1076 has the brand BASF. The above antioxidants are all purchased from Shanghai Kayin Chemical Co., Ltd.

[0017] Example 1 A preparation method of recycled PMMA material based on waste headlight plastics, comprising the following steps: Under the conditions of room temperature and nitrogen protection, blend waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent for 20 min to obtain a blend; under the conditions of a temperature of 250 °C and a screw speed of 300 rpm, melt and extrude the blend through a twin-screw extruder to granulate, thus obtaining the product. Among them, the preparation method of the modified silane coupling agent is as follows: Step S1: Add silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide to N,N-dimethylformamide under the conditions of 60 °C, nitrogen atmosphere, and stirring, react for 6 h, filter after natural cooling to room temperature to obtain a filtrate, and then rotary evaporate the filtrate to remove N,N-dimethylformamide under the conditions of a temperature of 80 °C, a rotation rate of 120 rpm, and a vacuum degree of 25-50 mbar to obtain an intermediate. The molar ratio of silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide is 1:1.1:0.1, and the addition amount of silane coupling agent KH-560 in N,N-dimethylformamide is 0.05 g / mL. Step S2: Under the conditions of 100 °C and stirring, add the intermediate obtained in Step S1, aluminum trichloride, and 5-carboxybenzotriazole to N,N-dimethylformamide, react for 5 h, naturally cool to room temperature, then filter to obtain a filtrate. Then, under the conditions of a temperature of 80 °C, a rotation rate of 120 rpm, and a vacuum of 25 - 50 mbar, rotary evaporate the filtrate to remove N,N-dimethylformamide. The molar ratio of the intermediate, aluminum trichloride, and 5-carboxybenzotriazole is 1:0.9:0.05, and the addition amount of 5-carboxybenzotriazole in N,N-dimethylformamide is 0.04 g / mL; The synthesis route of the modified silane coupling agent is as follows: ; ; The NMR results of the modified silane coupling agent are as follows: 1 H NMR (300 MHz, acetone-d6) δ 16.16 (s, 1H), 8.71 (s, 1H), 8.07 (d, 2H), 5.89 (s, 1H), 4.82 (d, 1H), 4.46 - 4.56 (m, 4H), 3.65 - 3.90 (m, 2H), 3.48 - 3.59 (m, 9H), 3.35 (d, 2H), 2.92 - 3.17 (m, 2H), 1.42 (d, 2H), 1.20 (t, 6H), 0.56 (d, 2H).

[0018] Among them, the weight ratio of waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent is 70:5:1:5:1:1:1. The toughening agent is methyl methacrylate-butadiene-styrene copolymer, the lubricant is stearamide, the antioxidant is antioxidant 300, and the antistatic agent is dibenzoyl peroxide.

[0019] Example 2 A preparation method of recycled PMMA material based on waste headlight plastics, comprising the following steps: Under the conditions of room temperature and nitrogen protection, blend waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent for 20 min to obtain a blend; under the conditions of a temperature of 250 °C and a screw speed of 300 rpm, melt and extrude the blend through a twin-screw extruder to granulate, and that's it; The preparation method of the modified silane coupling agent is as follows: Step S1: Under the conditions of 80 °C, nitrogen atmosphere, and stirring, add silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide to N,N-dimethylformamide, react for 4 h, filter after naturally cooling to room temperature to obtain a filtrate, and then rotary evaporate the filtrate to remove N,N-dimethylformamide under the conditions of a temperature of 80 °C, a rotation rate of 120 rpm, and a vacuum degree of 25 - 50 mbar to obtain an intermediate. The molar ratio of silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide is 1:1.2:0.15, and the addition amount of silane coupling agent KH-560 in N,N-dimethylformamide is 0.06 g / mL; Step S2: Under the conditions of 110 °C and stirring, add the intermediate obtained in Step S1, aluminum trichloride, and 5-carboxybenzotriazole to N,N-dimethylformamide, react for 3 h, filter after naturally cooling to room temperature to obtain a filtrate, and then rotary evaporate the filtrate to remove N,N-dimethylformamide under the conditions of a temperature of 80 °C, a rotation rate of 120 rpm, and a vacuum degree of 25 - 50 mbar. The molar ratio of the intermediate, aluminum trichloride, and 5-carboxybenzotriazole is 1:1:0.06, and the addition amount of 5-carboxybenzotriazole in N,N-dimethylformamide is 0.05 g / mL; Among them, the weight ratio of waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent is 70:10:5:8:5:3:3. The toughening agent is acrylonitrile-butadiene-styrene copolymer, the lubricant is calcium stearate, the antioxidant is antioxidant 264, and the antistatic agent is diisopropylbenzene peroxide.

[0020] Example 3 A preparation method of a regenerated PMMA material based on waste headlight plastics, comprising the following steps: Under room temperature conditions and nitrogen protection, blend waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent for 20 min to obtain a blend; melt and extrude granulate the blend through a twin-screw extruder under the conditions of a temperature of 250 °C and a screw rotation speed of 300 rpm to obtain the product; Among them, the preparation method of the modified silane coupling agent is as follows: Step S1: Under the conditions of 70 °C, nitrogen atmosphere, and stirring, add silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide to N,N-dimethylformamide, react for 5 h, filter after natural cooling to room temperature to obtain a filtrate, and then rotary evaporate the filtrate to remove N,N-dimethylformamide under the conditions of a temperature of 80 °C, a rotation rate of 120 rpm, and a vacuum degree of 25-50 mbar to obtain an intermediate. The molar ratio of silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide is 1:1.15:0.12, and the addition amount of silane coupling agent KH-560 in N,N-dimethylformamide is 0.055 g / mL; Step S2: Under the conditions of 105 °C and stirring, add the intermediate obtained in Step S1, aluminum trichloride, and 5-carboxybenzotriazole to N,N-dimethylformamide, react for 4 h, filter after natural cooling to room temperature to obtain a filtrate, and then rotary evaporate the filtrate to remove N,N-dimethylformamide under the conditions of a temperature of 80 °C, a rotation rate of 120 rpm, and a vacuum degree of 25-50 mbar. The molar ratio of the intermediate, aluminum trichloride, and 5-carboxybenzotriazole is 1:0.95:0.055, and the addition amount of 5-carboxybenzotriazole in N,N-dimethylformamide is 0.045 g / mL; The weight parts ratio of waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent is 70:8:3:6:3:2:2. The toughening agent is POE plastic, the lubricant is zinc stearate, the antioxidant is antioxidant 168, and the antistatic agent is isocyanate.

[0021] Comparative Example 1 A preparation method of recycled PMMA material based on waste headlight plastics, comprising the following steps: Under the conditions of room temperature and nitrogen protection, blend waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent for 20 min to obtain a blend; melt and extrude granulate the blend through a twin-screw extruder under the conditions of a temperature of 250 °C and a screw speed of 300 rpm to obtain the product; The preparation method of the modified silane coupling agent is as follows: Step S1: Under the conditions of 50 °C, nitrogen atmosphere, and stirring, add silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide to N,N-dimethylformamide, react for 2 h, filter after naturally cooling to room temperature to obtain a filtrate, and then rotary evaporate the filtrate to remove N,N-dimethylformamide under the conditions of a temperature of 80 °C, a rotation rate of 120 rpm, and a vacuum degree of 25-50 mbar to obtain an intermediate. The molar ratio of silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide is 1:1.15:0.12, and the addition amount of silane coupling agent KH-560 in N,N-dimethylformamide is 0.055 g / mL; Step S2: Under the conditions of 80 °C and stirring, add the intermediate obtained in Step S1, aluminum trichloride, and 5-carboxybenzotriazole to N,N-dimethylformamide, react for 2 h, filter after naturally cooling to room temperature to obtain a filtrate, and then rotary evaporate the filtrate to remove N,N-dimethylformamide under the conditions of a temperature of 80 °C, a rotation rate of 120 rpm, and a vacuum degree of 25-50 mbar. The molar ratio of the intermediate, aluminum trichloride, and 5-carboxybenzotriazole is 1:0.95:0.055, and the addition amount of 5-carboxybenzotriazole in N,N-dimethylformamide is 0.045 g / mL; Among them, the weight parts ratio of waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent is 70:1:0.1:6:3:2:2. The toughening agent is POE plastic, the lubricant is zinc stearate, the antioxidant is antioxidant 168, and the antistatic agent is isocyanate.

[0022] Comparative Example 2 A preparation method of recycled PMMA material based on waste headlight plastic, comprising the following steps: Under the conditions of room temperature and nitrogen protection, blend waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent for 20 min to obtain a blend; melt and extrude granulate the blend through a twin-screw extruder under the conditions of a temperature of 250 °C and a screw rotation speed of 300 rpm; Among them, the preparation method of the modified silane coupling agent is as follows: Under the conditions of 70 °C, nitrogen atmosphere, and stirring, add silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide to N,N-dimethylformamide, react for 5 h, filter after naturally cooling to room temperature to obtain a filtrate, and then rotary evaporate the filtrate to remove N,N-dimethylformamide under the conditions of a temperature of 80 °C, a rotation rate of 120 rpm, and a vacuum degree of 25-50 mbar to obtain a modified silane coupling agent. The molar ratio of silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide is 1:1.15:0.12, and the addition amount of silane coupling agent KH-560 in N,N-dimethylformamide is 0.055 g / mL; Among them, the weight ratio of waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent is 70:8:3:6:3:2:2. The toughening agent is POE plastic, the lubricant is zinc stearate, the antioxidant is antioxidant 168, and the antistatic agent is isocyanate.

[0023] Comparative Example 3 A preparation method of recycled PMMA material based on waste headlight plastic includes the following steps: Under room temperature conditions and nitrogen protection, waste PMMA particles, nano-silica, silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent are blended for 20 min to obtain a blend; under the conditions of a temperature of 250 °C and a screw speed of 300 rpm, the blend is melted and extruded into pellets through a twin-screw extruder, thus obtaining the product. Among them, the preparation method of the modified silane coupling agent is as follows: Among them, the weight ratio of waste PMMA particles, nano-silica, silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent is 70:8:3:6:3:2:2. The toughening agent is POE plastic, the lubricant is zinc stearate, the antioxidant is antioxidant 168, and the antistatic agent is isocyanate.

[0024] The properties of the recycled PMMA materials based on waste headlight plastic prepared in Examples 1-3 and Comparative Examples 1-3 are tested. The test method is as follows, and the test results are shown in Table 1 below.

[0025] Test sample preparation method: The recycled PMMA material particles based on waste headlight plastic prepared in Examples 1-3 and Comparative Examples 1-3 above are respectively added to an injection molding machine, melted and processed, and then cooled and formed. Among them, the temperature of the injection molding machine is 220-250 °C, and the specific dimensions of the samples are determined according to the requirements of the following various test methods.

[0026] Tensile property test According to GB / T 1040.2-2022 Plastics - Determination of tensile properties - Part 2: Test conditions for moulding and extrusion plastics, the tensile strength of the test specimens is tested.

[0027] Impact resistance test According to GB / T 1843 Plastics - Determination of the charpy impact strength, the impact resistance of the test specimens is tested.

[0028] Surface hardness test According to GB / T 3398.2-2008 Plastics - Determination of hardness - Part 2: Rockwell hardness, the hardness of the test specimens is tested, and the scale of the Rockwell hardness is the M scale.

[0029] Heat resistance test The Vicat softening temperature of the test specimens was measured in accordance with GB / T 1633-2000 "Determination of Vicat softening temperature (VST) of semi-rigid plastics".

[0030] Anti-ultraviolet performance test In accordance with the method described in GB / T 16422.3-2022 "Plastics - Methods of exposure to laboratory light sources - Part 3: Fluorescent UV lamps", a UVA-340 (type 1A) fluorescent UV lamp, a black standard thermometer, and exposure cycle 1 were selected for irradiation. After 10 exposure cycles, the yellow index of the sample after irradiation with the fluorescent UV lamp was measured in accordance with HG / T 3862-2006 "Test method for yellow index of plastics", and the yellowing index △YI was obtained.

[0031] Flame retardant performance test The oxygen index value of the sample was measured in accordance with the method described in GB / T 2406.2-2009 "Plastics - Determination of burning behavior by oxygen index - Part 2: Ambient temperature test".

[0032] Performance tests of various PMMA materials in Table 1 Through a series of performance tests on the recycled PMMA materials based on waste headlamp plastics prepared in Examples 1-3, it can be seen that the PMMA materials prepared by this method show excellent performance in multiple performance indicators. The recycled PMMA materials based on waste headlamp plastics prepared in Examples 1-3 have excellent flame retardant performance and anti-ultraviolet ability. In addition, they also have a relatively high Vicat softening temperature and Rockwell hardness, good tensile strength and impact strength, which makes the recycled PMMA materials based on waste headlamp plastics prepared by this preparation method can be widely used in the fields of automobiles, electronics, and construction.

[0033] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0034] Although the embodiments of the present application have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents.

Claims

1. Preparation method of recycled PMMA material based on waste headlight plastics, characterized in that It includes the following steps: Under nitrogen protection, waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent are blended to obtain a blend; the blend is melted and extruded into pellets through a screw extruder, and that's it. The preparation method of the said modified silane coupling agent is as follows: Step S1: Under the conditions of 60 - 80 °C, nitrogen atmosphere, and stirring, add silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide to N,N-dimethylformamide, react for 4 - 6 h, cool to room temperature, and purify to obtain an intermediate. The structural formula of the intermediate is: ； Step S2: Under the conditions of 100 - 110 °C and stirring, add the intermediate obtained in Step S1, aluminum trichloride, and 5-carboxybenzotriazole to N,N-dimethylformamide, react for 3 - 5 h, cool to room temperature, and purify to obtain the modified silane coupling agent. The structural formula of the modified silane coupling agent is: 。 2. The preparation method of the recycled PMMA material based on waste headlight plastics according to claim 1, wherein, The weight ratio of the said waste PMMA particles, nano-silica, modified silane coupling agent, toughening agent, lubricant, antioxidant, and antistatic agent is 70:5 - 10:1 - 5:5 - 8:1 - 5:1 - 3:1 - 3.

3. The preparation method of the recycled PMMA material based on waste headlight plastics according to claim 1, wherein, In Step S1, the molar ratio of silane coupling agent KH-560, diethyl pyrophosphoramide, and sodium hydroxide is 1:1.1 - 1.2:0.1 - 0.15, and the addition amount of silane coupling agent KH-560 in N,N-dimethylformamide is 0.05 - 0.06 g / mL.

4. The preparation method of the recycled PMMA material based on waste headlight plastics according to claim 1, characterized in that, In Step S2, the molar ratio of the intermediate, aluminum trichloride, and 5-carboxybenzotriazole is 1:0.9 - 1:0.05 - 0.06, and the addition amount of 5-carboxybenzotriazole in N,N-dimethylformamide is 0.04 - 0.05 g / mL.

5. The preparation method of the recycled PMMA material based on waste headlight plastics according to claim 1, characterized in that, The said toughening agent is one or more of methyl methacrylate-butadiene-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, POE plastic, and GMA plastic.

6. The preparation method of the recycled PMMA material based on waste headlight plastics according to claim 1, characterized in that, The said lubricant is one or more of stearamide, calcium stearate, zinc stearate, and pentaerythritol stearate.

7. The preparation method of the recycled PMMA material based on waste headlight plastics according to claim 1, characterized in that, The said antioxidant is one or more of antioxidant 300, antioxidant 264, antioxidant 168, antioxidant 618, antioxidant 1010, and antioxidant 1076.

8. The preparation method of the recycled PMMA material based on waste headlight plastics according to claim 1, characterized in that, The said antistatic agent is one or more of dibenzoyl peroxide, diisopropylbenzene peroxide, isocyanate, and sodium dodecylbenzenesulfonate.

Images