Weather-resistant and ultraviolet-resistant plastic particle and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and discloses weather-resistant and ultraviolet-resistant plastic particles and a preparation method thereof.The weather-resistant and ultraviolet-resistant plastic particles are prepared from, by weight, 180-220 parts of PVC resin, 55-70 parts of ethylene propylene diene monomer, 15-20 parts of modified nano titanium dioxide, 5-10 parts of an ultraviolet screening agent, 10-15 parts of a composite flame retardant, 20-35 parts of a plasticizer and 3-5 parts of a lubricant; the modified nano titanium dioxide is nano titanium dioxide subjected to surface modification by a silane coupling agent, and the ultraviolet screening agent is obtained by reacting 2, 2, 6, 6-tetramethylpiperidinol with dimethyl-(E)-sym-diphenylethyl-4, 4-oxalic acid ester and then copolymerizing with styrene. The light stability of the material is effectively improved, so that the material has good weather-resistant and ultraviolet-resistant effects.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to weather-resistant and ultraviolet-resistant plastic particles and a preparation method thereof. Background Art

[0002] Polyvinyl chloride (PVC) is one of the most common types of general synthetic resins. Its usage ranks second among commonly used thermoplastic resins, accounting for about one-third of the total global consumption of synthetic resins. PVC is a relatively common material in the plastic molding and processing industry. The advantages of PVC are excellent physical properties, good corrosion resistance, chemical stability, flame retardancy, etc., and its low price. It can play an important role in replacing traditional metals and wood in some fields. As the most cost-effective general engineering plastic, PVC has a low soft melting point in processing and manufacturing compared to other materials, and its products have superior mechanical properties, insulation, transparency, and processability.

[0003] However, PVC materials have poor light stability. Long-term exposure to ultraviolet light will cause rapid light aging and discoloration, thus losing their use value. The ideal PVC structure does not have functional groups that absorb ultraviolet light in the wavelength range of 190-220nm, but in reality, long-term exposure of PVC products outdoors will cause various performances of the products to deteriorate. At the same time, as the PVC molecules crosslink and break, the molecular weight will change, and hydrogen chloride will be released. This is due to the unstable factors (such as double bonds, allyl chloride, tertiary chloride, peroxide residues, carbonyl groups, etc.) generated during the polymerization and processing of PVC. These defect sites are the main cause of PVC photodegradation.

[0004] Therefore, light stabilizers are usually added during PVC material processing to inhibit or slow down the aging and degradation of polymer materials due to photooxidation. Currently, light stabilizers are still low-molecular light stabilizers. However, when low-molecular light stabilizers are used in polymer materials, they are prone to decomposition, migration, and frosting when heated, thus losing their anti-aging effect. Summary of the invention

[0005] In order to solve the deficiencies mentioned in the above background technology, the purpose of the present invention is to provide a weather-resistant and UV-resistant plastic particle and a preparation method thereof. By adding modified nano titanium dioxide and UV shielding agent, the light stability of the material is effectively improved, so that it has good weather-resistant and UV-resistant effects.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A weather-resistant and ultraviolet-resistant plastic particle comprises the following raw materials in parts by weight: 180-220 parts of PVC resin, 55-70 parts of EPDM rubber, 15-20 parts of modified nano titanium dioxide, 5-10 parts of ultraviolet shielding agent, 10-15 parts of composite flame retardant, 20-35 parts of plasticizer, and 3-5 parts of lubricant;

[0008] The modified nano titanium dioxide is nano titanium dioxide with a surface modified by a silane coupling agent; the ultraviolet shielding agent is obtained by copolymerizing styrene with 2,2,6,6-tetramethylpiperidinol and dimethyl-(E)-stilbene-4,4-oxalate, and the molecular structure of the ultraviolet shielding agent is as follows:

[0009]

[0010] More preferably, the plasticizer is selected from one or more of dibutyl phthalate, dioctyl phthalate, chlorinated paraffin, phosphate ester, and epoxidized soybean oil.

[0011] More preferably, the lubricant is one or more of stearate, paraffin and polyethylene wax.

[0012] Further preferably, the composite flame retardant is a mixture of aluminum hydroxide, ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 5:2.5:1:1.

[0013] Further preferably, the preparation method of modified nano titanium dioxide comprises the following steps:

[0014] A. Add nano titanium dioxide powder into 90 vol% ethanol aqueous solution, stir evenly and then ultrasonically disperse for 1 to 2 hours to obtain nano titanium dioxide dispersion;

[0015] B. Add 3-aminopropyltrimethoxysilane to the dispersion, heat to 80°C with stirring and react for 3-5 hours, centrifuge, wash, filter and dry to obtain modified titanium dioxide.

[0016] Further preferably, the nano titanium dioxide powder is added to the ethanol solution at a solid-liquid ratio of 1:15-20, and the mass ratio of the 3-aminopropyltrimethoxysilane to the nano titanium dioxide powder is 1:5-8.

[0017] Further preferably, the preparation method of the ultraviolet shielding agent comprises the following steps:

[0018] (1) 2,2,6,6-tetramethylpiperidinol, dimethyl-(E)-stilbene-4,4-oxalate and toluene are added to a reactor, heated to 50-60°C and stirred to dissolve, and then tetrabutyl titanate is added, and the temperature is raised to 100-105°C, and nitrogen protection is used for reaction for 8-12 hours. The product is precipitated with anhydrous ether and washed several times, and vacuum dried to obtain intermediate A;

[0019] (2) Add intermediate A and styrene to a reactor, then add toluene solvent, pass nitrogen protection, heat to 75-85° C., add initiator dibenzoyl peroxide, react for 20-24 hours, remove toluene solvent by vacuum distillation, precipitate with anhydrous ether and wash several times, and dry to obtain the ultraviolet shielding agent.

[0020] More preferably, the molar ratio of 2,2,6,6-tetramethylpiperidinol to dimethyl-(E)-stilbene-4,4-oxalate is 2-3:1, and tetrabutyl titanate accounts for 2-3% of the total weight of the monomers.

[0021] More preferably, the molar ratio of intermediate A to styrene is 1:3-4, and dibenzoyl peroxide accounts for 1-2% of the total weight of the monomers.

[0022] A method for preparing weather-resistant and UV-resistant plastic particles comprises the following steps:

[0023] S1, adding PVC resin, EPDM rubber, plasticizer and lubricant into a high mixing pot and mixing them thoroughly, then melting, plasticizing and blending the mixture through a twin-screw extruder, and extruding and granulating to obtain polymer particles;

[0024] S2. Add the polymer particles, modified nano titanium dioxide, UV shielding agent and composite flame retardant into a high mixing pot for premixing, then melt and blend the mixture through a twin-screw extruder, extrude and granulate the mixture, and dry it to obtain weather-resistant and UV-resistant plastic particles.

[0025] Beneficial effects of the present invention:

[0026] The invention has weather-resistant and UV-resistant plastic particles. By adding modified nano titanium dioxide and UV shielding agents, the light stability of the material is effectively improved, so that it has good weather-resistant and UV-resistant effects. The invention uses a silane coupling agent to modify the surface of nano titanium dioxide, thereby improving the dispersibility of nano carbon dioxide in the plastic matrix, effectively preventing the agglomeration of nano titanium dioxide, thereby better exerting the UV capture effect and improving the UV oxidation resistance of the material. At the same time, the invention is obtained by copolymerizing styrene after reacting 2,2,6,6-tetramethylpiperidinol with dimethyl-(E)-stilbene-4,4-oxalate. The molecular chain contains a hindered amine structure, which has a synergistic effect with nano titanium dioxide, can greatly improve the light stability of the material, and at the same time, due to copolymerization with styrene, the molecular weight of the composite stabilizer is increased, so that it can be better compatible with polyvinyl chloride, and is not easy to decompose and migrate, ensuring that the material has long-term aging resistance. 。 DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] A modified nano titanium dioxide is obtained by surface modification of nano titanium dioxide by a silane coupling agent, and the preparation method thereof comprises the following steps:

[0030] A. Add 6.5 g of nano titanium dioxide powder into 100 ml of 90 vol% ethanol aqueous solution, stir evenly and disperse by ultrasonic for 2 h to obtain a nano titanium dioxide dispersion;

[0031] B. Add 1.2 g of 3-aminopropyltrimethoxysilane to the dispersion, heat to 80° C. with stirring and react for 4 h, centrifuge, wash, filter and dry to obtain modified titanium dioxide.

[0032] Example 2

[0033] A UV shielding agent is obtained by reacting 2,2,6,6-tetramethylpiperidinol with dimethyl-(E)-stilbene-4,4-oxalate and then copolymerizing with styrene. The molecular structure of the UV shielding agent is as follows:

[0034]

[0035] The preparation method of the above-mentioned ultraviolet shielding agent comprises the following steps:

[0036] (1) 3.8 g of 2,2,6,6-tetramethylpiperidinol, 3.0 g of dimethyl-(E)-stilbene-4,4-ethanedioate and 60 ml of toluene were added to a reactor, heated to 55°C and stirred to dissolve, then 0.15 g of tetrabutyl titanate was added, the temperature was raised to 103°C, nitrogen protection was applied, the reaction was carried out for 10 h, the product was precipitated with anhydrous ether and washed several times, and vacuum dried to obtain intermediate A. The structure of intermediate A is as follows:

[0037]

[0038] (2) 5.9 g of intermediate A and 4.1 g of styrene were added to a reactor, and then 40 ml of toluene solvent was added, nitrogen was passed through the reactor, the temperature was raised to 80° C., 0.15 g of initiator dibenzoyl peroxide was added, the reaction was continued for 24 h, the toluene solvent was removed by vacuum distillation, the mixture was precipitated with anhydrous ether and washed several times, and the ultraviolet shielding agent was obtained by drying.

[0039] Example 3

[0040] A weather-resistant and ultraviolet-resistant plastic particle comprises the following raw materials in parts by weight: 220 parts of PVC resin, 55 parts of EPDM rubber, 20 parts of modified nano titanium dioxide, 5 parts of ultraviolet shielding agent, 15 parts of composite flame retardant, 10 parts of dibutyl phthalate, 10 parts of chlorinated paraffin and 5 parts of paraffin; the composite flame retardant is prepared by mixing aluminum hydroxide, ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 5:2.5:1:1; the modified nano titanium dioxide is the nano titanium dioxide surface-modified by a silane coupling agent prepared in Example 1; the ultraviolet shielding agent is obtained by copolymerizing styrene after reacting 2,2,6,6-tetramethylpiperidinol with dimethyl-(E)-stilbene-4,4-oxalate in Example 2.

[0041] The method for preparing the above-mentioned weather-resistant and UV-resistant plastic particles comprises the following steps:

[0042] S1, adding PVC resin, EPDM rubber, dibutyl phthalate, chlorinated paraffin and paraffin into a high mixing pot and mixing them thoroughly, then melting, plasticizing and blending the mixture through a twin-screw extruder, and extruding and granulating to obtain polymer particles;

[0043] S2. Add the polymer particles, modified nano titanium dioxide, UV shielding agent and composite flame retardant into a high mixing pot for premixing, then melt and blend the mixture through a twin-screw extruder, extrude and granulate the mixture, and dry it to obtain weather-resistant and UV-resistant plastic particles.

[0044] Example 4

[0045] A weather-resistant and ultraviolet-resistant plastic particle comprises the following raw materials in parts by weight: 180 parts of PVC resin, 70 parts of EPDM rubber, 15 parts of modified nano titanium dioxide, 10 parts of ultraviolet shielding agent, 10 parts of composite flame retardant, 20 parts of dioctyl phthalate, 15 parts of phosphate ester and 3 parts of polyethylene wax; the composite flame retardant is prepared by mixing aluminum hydroxide, ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 5:2.5:1:1; the modified nano titanium dioxide is the nano titanium dioxide surface-modified by a silane coupling agent prepared in Example 1; the ultraviolet shielding agent is obtained by copolymerizing styrene after reacting 2,2,6,6-tetramethylpiperidinol with dimethyl-(E)-stilbene-4,4-oxalate in Example 2.

[0046] The method for preparing the above-mentioned weather-resistant and UV-resistant plastic particles comprises the following steps:

[0047] S1, adding PVC resin, EPDM rubber, dioctyl phthalate, phosphate ester and polyethylene wax into a high mixing pot and mixing them thoroughly, then melting, plasticizing and blending the mixture through a twin-screw extruder, and extruding and granulating to obtain polymer particles;

[0048] S2. Add the polymer particles, modified nano titanium dioxide, UV shielding agent and composite flame retardant into a high mixing pot for premixing, then melt and blend the mixture through a twin-screw extruder, extrude and granulate the mixture, and dry it to obtain weather-resistant and UV-resistant plastic particles.

[0049] Example 5

[0050] A weather-resistant and ultraviolet-resistant plastic particle comprises the following raw materials in parts by weight: 200 parts of PVC resin, 62 parts of EPDM rubber, 18 parts of modified nano titanium dioxide, 7 parts of ultraviolet shielding agent, 13 parts of composite flame retardant, 18 parts of dibutyl phthalate, 10 parts of epoxy soybean oil and 4 parts of sodium stearate; the composite flame retardant is prepared by mixing aluminum hydroxide, ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 5:2.5:1:1; the modified nano titanium dioxide is the nano titanium dioxide surface-modified by a silane coupling agent prepared in Example 1; the ultraviolet shielding agent is obtained by copolymerizing styrene after reacting 2,2,6,6-tetramethylpiperidinol with dimethyl-(E)-stilbene-4,4-oxalate in Example 2.

[0051] The method for preparing the above-mentioned weather-resistant and UV-resistant plastic particles comprises the following steps:

[0052] S1, adding PVC resin, EPDM rubber, dibutyl phthalate, epoxy soybean oil and sodium stearate into a high mixing pot and mixing them thoroughly, then melting, plasticizing and blending the mixture through a twin-screw extruder, and extruding and granulating to obtain polymer particles;

[0053] S2. Add the polymer particles, modified nano titanium dioxide, UV shielding agent and composite flame retardant into a high mixing pot for premixing, then melt and blend the mixture through a twin-screw extruder, extrude and granulate the mixture, and dry it to obtain weather-resistant and UV-resistant plastic particles.

[0054] Comparative Example 1

[0055] A weather-resistant and UV-resistant plastic particle comprises the following raw materials in parts by weight: 200 parts of PVC resin, 62 parts of EPDM rubber, 7 parts of UV shielding agent, 13 parts of composite flame retardant, 18 parts of dibutyl phthalate, 10 parts of epoxy soybean oil and 4 parts of sodium stearate; the composite flame retardant is prepared by mixing aluminum hydroxide, ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 5:2.5:1:1; the UV shielding agent is obtained by copolymerizing styrene with 2,2,6,6-tetramethylpiperidinol in Example 2 and dimethyl-(E)-stilbene-4,4-oxalate.

[0056] The method for preparing the above-mentioned weather-resistant and UV-resistant plastic particles comprises the following steps:

[0057] S1, adding PVC resin, EPDM rubber, dibutyl phthalate, epoxy soybean oil and sodium stearate into a high mixing pot and mixing them thoroughly, then melting, plasticizing and blending the mixture through a twin-screw extruder, and extruding and granulating to obtain polymer particles;

[0058] S2. Add the polymer particles, UV shielding agent and composite flame retardant into a high mixing pot for premixing, then melt and blend the mixture through a twin-screw extruder, extrude and granulate the mixture, and dry it to obtain weather-resistant and UV-resistant plastic particles.

[0059] Comparative Example 2

[0060] A weather-resistant and ultraviolet-resistant plastic particle comprises the following raw materials in parts by weight: 200 parts of PVC resin, 62 parts of EPDM rubber, 18 parts of modified nano titanium dioxide, 13 parts of a composite flame retardant, 18 parts of dibutyl phthalate, 10 parts of epoxy soybean oil, and 4 parts of sodium stearate; the composite flame retardant is prepared by mixing aluminum hydroxide, ammonium polyphosphate, pentaerythritol, and melamine in a mass ratio of 5:2.5:1:1; the modified nano titanium dioxide is the nano titanium dioxide surface-modified with a silane coupling agent prepared in Example 1.

[0061] The method for preparing the above-mentioned weather-resistant and UV-resistant plastic particles comprises the following steps:

[0062] S1, adding PVC resin, EPDM rubber, dibutyl phthalate, epoxy soybean oil and sodium stearate into a high mixing pot and mixing them thoroughly, then melting, plasticizing and blending the mixture through a twin-screw extruder, and extruding and granulating to obtain polymer particles;

[0063] S2. Add the polymer particles, modified nano titanium dioxide and composite flame retardant into a high mixing pot for premixing, then melt and blend the mixture through a twin-screw extruder, extrude and granulate the mixture, and dry it to obtain weather-resistant and UV-resistant plastic particles.

[0064] Comparative Example 3

[0065] A weather-resistant and ultraviolet-resistant plastic particle comprises the following raw materials in parts by weight: 200 parts of PVC resin, 62 parts of EPDM rubber, 13 parts of a composite flame retardant, 18 parts of dibutyl phthalate, 10 parts of epoxy soybean oil, and 4 parts of sodium stearate; the composite flame retardant is prepared by mixing aluminum hydroxide, ammonium polyphosphate, pentaerythritol, and melamine in a mass ratio of 5:2.5:1:1.

[0066] The method for preparing the above-mentioned weather-resistant and UV-resistant plastic particles comprises the following steps:

[0067] S1, adding PVC resin, EPDM rubber, dibutyl phthalate, epoxy soybean oil and sodium stearate into a high mixing pot and mixing them thoroughly, then melting, plasticizing and blending the mixture through a twin-screw extruder, and extruding and granulating to obtain polymer particles;

[0068] S2. Add the polymer particles and the composite flame retardant into a high mixing pot for premixing, then melt and blend the mixture through a twin-screw extruder, extrude and granulate the mixture, and dry it to obtain weather-resistant and UV-resistant plastic particles.

[0069] Performance Testing

[0070] The weather-resistant and UV-resistant plastic particles prepared in Examples 3 to 5 and Comparative Examples 1 to 3 were melt-extruded through a screw extruder and then cooled. The samples were cut into 25 mm × 4 mm dumbbell-shaped tensile specimens and placed in a UV light box for accelerated aging. The photostability test was performed, and the tensile strength was tested every 10 hours. The tensile strength test was conducted in accordance with GB / T 528-2009, with a tensile rate of 20 mm / min. The tensile strength retention rate was calculated by comparing with the initial tensile strength, and the data were shown in Table 1 below.

[0071] Table 1 Test results of light stability of weather-resistant and UV-resistant plastic particles

[0072]

[0073] It can be seen from the data in Table 1 that the light stability of the weather-resistant and UV-resistant plastic particles prepared in Examples 3 to 5 of the present invention is excellent. After 40 hours of accelerated aging, the tensile strength retention rate can still reach more than 70%. In Comparative Example 1, no modified nano titanium dioxide is added, and in Comparative Example 2, no ultraviolet shielding agent is added. The light stability of the material is reduced, and in Comparative Example 3, the plastic particles without modified nano titanium dioxide and ultraviolet shielding agent are not added. The ultraviolet aging resistance decreases significantly, indicating that the modified nano titanium dioxide and ultraviolet shielding agent of the present invention jointly play an anti-ultraviolet oxidation role. The present invention improves the dispersibility of nano carbon dioxide in the plastic matrix by surface-modifying nano titanium dioxide with a silane coupling agent, effectively preventing the agglomeration of nano titanium dioxide, thereby better playing the ultraviolet capture effect and improving the ultraviolet oxidation resistance of the material. At the same time, the present invention is obtained by copolymerizing styrene after reacting 2,2,6,6-tetramethylpiperidinol with dimethyl-(E)-stilbene-4,4-oxalate, and contains a hindered amine structure in the molecular chain, which has a synergistic effect with nano titanium dioxide and can greatly improve the light stability of the material. At the same time, due to the copolymerization with styrene, the molecular weight of the composite stabilizer is increased, so that it can be better compatible with polyvinyl chloride, and is not easy to decompose and migrate, thereby ensuring that the material has long-term aging resistance.

[0074] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0075] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A weather-resistant and UV-resistant plastic particle, characterized in that: The invention comprises the following raw materials in parts by weight: 180-220 parts of PVC resin, 55-70 parts of EPDM rubber, 15-20 parts of modified nano titanium dioxide, 5-10 parts of ultraviolet shielding agent, 10-15 parts of composite flame retardant, 20-35 parts of plasticizer and 3-5 parts of lubricant; The modified nano titanium dioxide is nano titanium dioxide surface-modified by a silane coupling agent; the ultraviolet shielding agent is obtained by copolymerizing styrene with 2,2,6,6-tetramethylpiperidinol and dimethyl-(E)-stilbene-4,4-oxalate, and the molecular structure of the ultraviolet shielding agent is as follows:

2. The weather-resistant and UV-resistant plastic particles according to claim 1, characterized in that: The plasticizer is selected from one or more of dibutyl phthalate, dioctyl phthalate, chlorinated paraffin, phosphate ester, and epoxidized soybean oil.

3. The weather-resistant and UV-resistant plastic particles according to claim 1, characterized in that: The lubricant is one or more of stearate, paraffin and polyethylene wax.

4. The weather-resistant and UV-resistant plastic particles according to claim 1, characterized in that: The composite flame retardant is prepared by mixing aluminum hydroxide, ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of 5:2.5:1:

1.

5. The weather-resistant and UV-resistant plastic particles according to claim 1, characterized in that: The preparation method of the modified nano titanium dioxide comprises the following steps: A. Add nano titanium dioxide powder into 90 vol% ethanol aqueous solution, stir evenly and then ultrasonically disperse for 1 to 2 hours to obtain nano titanium dioxide dispersion; B. Add 3-aminopropyltrimethoxysilane to the dispersion, heat to 80°C with stirring and react for 3-5 hours, centrifuge, wash, filter and dry to obtain modified titanium dioxide.

6. The weather-resistant and UV-resistant plastic particles according to claim 5, characterized in that: The nano titanium dioxide powder is added into the ethanol solution at a solid-liquid ratio of 1:15-20, and the mass ratio of the 3-aminopropyltrimethoxysilane to the nano titanium dioxide powder is 1:5-8.

7. The weather-resistant and UV-resistant plastic particles according to claim 1, characterized in that: The preparation method of the ultraviolet shielding agent comprises the following steps: (1) 2,2,6,6-tetramethylpiperidinol, dimethyl-(E)-stilbene-4,4-oxalate and toluene are added to a reactor, heated to 50-60°C and stirred to dissolve, and then tetrabutyl titanate is added, and the temperature is raised to 100-105°C, and nitrogen protection is used for reaction for 8-12 hours. The product is precipitated with anhydrous ether and washed several times, and vacuum dried to obtain intermediate A; (2) Add intermediate A and styrene to a reactor, then add toluene solvent, pass nitrogen protection, heat to 75-85° C., add initiator dibenzoyl peroxide, react for 20-24 hours, remove toluene solvent by vacuum distillation, precipitate with anhydrous ether and wash several times, and dry to obtain the ultraviolet shielding agent.

8. The weather-resistant and UV-resistant plastic particles according to claim 7, characterized in that: The molar ratio of the 2,2,6,6-tetramethylpiperidinol and dimethyl-(E)-stilbene-4,4-oxalate is 2-3:1, and tetrabutyl titanate accounts for 2-3% of the total weight of the monomers.

9. The weather-resistant and UV-resistant plastic particles according to claim 7, characterized in that: The molar ratio of the intermediate A to styrene is 1:3-4, and dibenzoyl peroxide accounts for 1-2% of the total weight of the monomers.

10. The method for preparing weather-resistant and UV-resistant plastic particles according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, adding PVC resin, EPDM rubber, plasticizer and lubricant into a high mixing pot and mixing them thoroughly, then melting, plasticizing and blending the mixture through a twin-screw extruder, and extruding and granulating to obtain polymer particles; S2. Add the polymer particles, modified nano titanium dioxide, UV shielding agent and composite flame retardant into a high mixing pot for premixing, then melt and blend the mixture through a twin-screw extruder, extrude and granulate the mixture, and dry it to obtain weather-resistant and UV-resistant plastic particles.

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