Special antioxidant for ABS resin, its preparation method and application

Abstract

The application belongs to the field of resin additives, and discloses an ABS resin special antioxidant, a preparation method and application thereof, the antioxidant is compounded by a main antioxidant, an auxiliary antioxidant, a microencapsulated ultraviolet absorber and a dispersion protective agent according to a specific weight ratio, wherein the ultraviolet absorber is coated by a styrene-acrylonitrile copolymer to form microcapsules by an in-situ polymerization method, the particle size is 1-3 mu m, and the migration resistance and light stability are significantly improved. The dispersion protective agent is composed of a first component and a second component mixed according to a 2:1 ratio. The preparation method adopts a step-by-step mixing and gradient heating strategy to uniformly disperse each component, and finally obtains a flat round granular antioxidant through melt granulation. The antioxidant has less dust and good dispersibility, can significantly improve the oxidation resistance and anti-yellowing performance of ABS materials, and is suitable for high-performance processing and long-term stable application of ABS products.

Description

Technical Field

[0001] This invention belongs to the field of resin additives, specifically relating to an antioxidant for ABS resin, its preparation method, and its application. Background Technology

[0002] ABS resin is a widely used and high-volume general-purpose engineering plastic with excellent comprehensive physical and mechanical properties, good low-temperature impact resistance, dimensional stability, electrical properties, wear resistance, chemical corrosion resistance, dyeability, and processing performance. It is widely used in manufacturing industries such as machinery, electrical, textile, automotive, aerospace, and shipbuilding, as well as in the chemical industry.

[0003] Antioxidants, as additives used to inhibit and delay the oxidative degradation of polymer materials during processing and use, are particularly important in ABS resin. Currently, commonly used antioxidants in ABS resin mainly include hindered phenols and phosphites, such as antioxidants 1010, 1076, 168, and 626. These antioxidants can improve the antioxidant properties and thermal stability of ABS products to a certain extent, and are therefore widely accepted.

[0004] However, with the increasing demand for high-performance, high-value-added products in the resin processing industry, existing single antioxidants are no longer sufficient to meet the requirements of ABS in terms of color stability, long-term heat resistance, and ease of use. Single-agent antioxidants not only have limited antioxidant efficiency but are also mostly in powder form, leading to problems such as high dust levels, easy moisture absorption, and easy pipe clogging, affecting the production environment and processing efficiency. Therefore, improving antioxidant effects and optimizing their physical morphology through the synergistic compounding of different types of antioxidants has become a research hotspot in composite antioxidants in recent years. Summary of the Invention

[0005] To address the shortcomings mentioned in the background art, the present invention aims to provide a special antioxidant for ABS resin, its preparation method, and its application. The antioxidant is composed of a hindered phenolic primary antioxidant, a phosphite secondary antioxidant, a microencapsulated ultraviolet absorber, and a dispersant in a specific ratio. Microencapsulation technology enhances the photostability of the ultraviolet absorber, and a stepwise mixing and gradient heating process optimizes the component dispersion, ultimately producing flat, round antioxidant particles with low dust content, good dispersibility, strong anti-yellowing ability, and suitable for ABS resin processing.

[0006] The objective of this invention can be achieved through the following technical solutions: An antioxidant for ABS resin comprises the following raw materials in parts by weight: 30-60 parts of main antioxidant, 10-30 parts of auxiliary antioxidant, 10-25 parts of microencapsulated ultraviolet absorber, and 10-25 parts of dispersant protectant; The primary antioxidant is a hindered phenolic antioxidant; the secondary antioxidant is a phosphite antioxidant; the microencapsulated UV absorber is prepared by microencapsulation modification of a UV absorber through in-situ polymerization; and the dispersant is composed of a first component and a second component mixed in a weight ratio of 2:1.

[0007] More preferably, the hindered phenolic antioxidant is selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 245, and antioxidant 300; the phosphite antioxidant is selected from one or more of antioxidant 168, antioxidant 626, and antioxidant 618.

[0008] More preferably, the ultraviolet absorber is selected from one or more of ultraviolet absorbers UV-531, UV-326, and UV-327; the microencapsulated modified wall material is a styrene-acrylonitrile copolymer; and the particle size of the microencapsulated ultraviolet absorber is 1–3 μm.

[0009] More preferably, the first component of the dispersant is selected from one or more of silica, talc, diatomaceous earth, and zeolite; and the second component of the dispersant is selected from one or more of calcium oxide, aluminum oxide, and magnesium oxide.

[0010] More preferably, the microencapsulated ultraviolet absorber is prepared by the following method: the ultraviolet absorber is dispersed in deionized water, styrene-acrylonitrile copolymer monomer and initiator are added, and in-situ polymerization is carried out under stirring conditions. After the reaction is completed, the microencapsulated ultraviolet absorber is centrifuged, dried and sieved to obtain a particle size of 1 to 3 μm.

[0011] More preferably, the in-situ polymerization reaction is carried out at a temperature of 60–80 °C for 2–4 h, and the initiator is potassium persulfate.

[0012] A method for preparing an antioxidant specifically for ABS resin includes the following steps: S1. Weigh the first and second components of the dispersant and protective agent, add them to the mixer, premix and stir at room temperature until uniformly mixed to form a composite functional core; S2. Keep the mixing container closed, add the main antioxidant, and continue stirring to form a primary mixture with a core-shell structure; S3. Add auxiliary antioxidant and microencapsulated ultraviolet absorber to the mixer and continue stirring to obtain a homogeneous mixture; S4. The mixture is continuously conveyed to the granulator via an auger conveyor. After melting, plasticizing, extrusion, pelletizing and cooling processes, ABS resin-specific antioxidant is obtained.

[0013] More preferably, the stirring temperature in step S1 is 20-30°C and the stirring time is 0.4-0.6 hours; the stirring temperature in step S2 is 45-55°C and the stirring time is 0.2-0.4 hours; and the stirring temperature in step S3 is 65-75°C and the stirring time is 0.1-0.3 hours.

[0014] More preferably, in step S4, the granulation temperature of the granulator is 80-100℃, the pelletizing speed is 300-500 r / min, and the cooling process adopts air cooling with a cooling temperature of 25-30℃.

[0015] An application of an antioxidant specifically for ABS resin, used to improve the thermal oxidation stability and anti-yellowing properties of ABS resin.

[0016] The beneficial effects of this invention are: The composite antioxidant prepared in this invention exhibits a synergistic effect between hindered phenolic antioxidants and phosphite antioxidants. During the antioxidant process, hindered phenols capture polymer peroxide free radicals and transform into hydroperoxides, which then autocatalyze thermal hydroxyl degradation. Hindered phenols themselves cannot decompose hydroperoxides, so they are insufficient to achieve ideal antioxidant effects when used alone. Phosphite compounds, however, can decompose hydroperoxides, and the combined use of both achieves a complementary synergistic effect. This invention employs microencapsulation modification technology for UV absorbers, using styrene-acrylonitrile copolymers as wall materials. The UV absorbers are encapsulated through in-situ polymerization, controlling the particle size to 1–3 μm, achieving sustained-release stability, low migration, and significantly improving photostability and long-term anti-yellowing ability. Furthermore, a dispersant is added to the formulation. This improves the dispersibility of the composite antioxidant in the resin and forms a protective film on the resin surface, effectively isolating it from oxygen and other induction factors, reducing the risk of resin oxidation and discoloration. Through a unique process path of "stepwise mixing and gradient heating", the components are stably and uniformly dispersed and structured at different temperature stages. The resulting composite antioxidant particles are flat and round, with little dust, no clumping, no pipe blockage, and are easy to automate feeding and stable conveying. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1 The bar chart shows a comparison of the application performance test (yellowing index) results of the ABS resin-specific antioxidant prepared in the examples and comparative examples with those of conventional single-agent antioxidants. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: The ABS resin-specific antioxidant comprises the following raw materials in parts by weight: 50 parts of antioxidant 1076, 20 parts of antioxidant 168, 15 parts of microencapsulated ultraviolet absorber UV-531, 10 parts of silica, and 5 parts of alumina. (1) Preparation steps of microencapsulated ultraviolet absorber: The ultraviolet absorber was added to deionized water and dispersed at a high speed of 2500 r / min for 25 min to form a uniform aqueous dispersion of ultraviolet absorber; styrene-acrylonitrile copolymer monomer was added to the above dispersion, and then potassium persulfate initiator accounting for 0.8% of the monomer mass was added and stirred until completely dissolved; the reaction system was heated to 70℃ and polymerized in situ at a constant temperature of 600 r / min for 3 h to form a dense coating layer of styrene-acrylonitrile copolymer on the surface of ultraviolet absorber particles; after the polymerization reaction was completed, the reaction solution was placed in a centrifuge and centrifuged at a speed of 3500 r / min for 12 min, the solid product was collected, and the solid product was placed in a vacuum drying oven at 65℃ and dried to constant weight. Finally, it was sieved through a standard sieve of 2 μm to obtain microencapsulated ultraviolet absorber with a particle size of 1-3 μm.

[0021] (2) The preparation steps of the ABS resin-specific antioxidant are as follows: 100g of silica and 50g of alumina are added to a mixer at a mass ratio of 2:1 and stirred at 300 rpm for 0.5 hours at room temperature to form a uniformly dispersed composite functional core material. 500g of antioxidant 1076 is added to the mixer, the temperature is raised to 50℃, and stirring is continued for 0.3 hours (300 rpm) to construct a primary core-shell structure. 200g of antioxidant 168 and 150g of microencapsulated ultraviolet absorber UV-531 are simultaneously added to the mixer, the temperature is raised to 70℃, and stirring is continued for 0.2 hours (400 rpm). The mixture is conveyed to a twin-screw extruder through an auger, the barrel temperature is set to 90℃, the screw speed is 80 rpm, the material is melted and extruded through a die, and cut by a pelletizing mechanism at a speed of 400 r / min to obtain flat round particles with a particle size of about 3mm, which are the ABS resin-specific antioxidants.

[0022] Example 2: The ABS resin-specific antioxidant comprises the following raw materials in parts by weight: 45 parts antioxidant 1076, 20 parts antioxidant 168, 20 parts microencapsulated ultraviolet absorber UV-531, 10 parts silica, and 5 parts alumina. The preparation steps of the microencapsulated ultraviolet absorber are the same as in Example 1.

[0023] The preparation steps of the ABS resin-specific antioxidant are as follows: 100 g of weighed silica and 50 g of alumina are added to a mixer and stirred at 300 r / min for 0.5 h at room temperature to obtain a uniform composite functional core. While keeping the mixer closed, 450 g of antioxidant 1076 is added to the mixer, the temperature is raised to 45 ℃, and stirring is continued at 300 r / min for 0.2 h to form a primary mixture with a core-shell structure. 200 g of antioxidant 168 and 200 g of microencapsulated UV absorber UV-531 are simultaneously added to the mixer, the temperature is further raised to 65 ℃, the stirring speed is increased to 400 r / min, and stirring is continued for 0.1 h to obtain a homogeneous mixture. The resulting mixture is continuously conveyed to a twin-screw extruder granulator via a screw conveyor. The barrel temperature is set to 90 ℃ and the screw speed is set to 80 r / min. After melting and plasticizing, the mixture is extruded into strips and then pelletized at a pelletizing speed of 400 r / min. The resulting pellets are cooled to 25 ℃ by air cooling to obtain flat round composite antioxidant pellets with a particle size of about 2-4 mm, which are the ABS resin-specific antioxidants.

[0024] Example 3: The ABS resin-specific antioxidant comprises the following raw materials in parts by weight: 50 parts of antioxidant 1076, 20 parts of antioxidant 618, 15 parts of microencapsulated ultraviolet absorber UV-531, 10 parts of talc, and 5 parts of magnesium oxide. The preparation steps of the microencapsulated ultraviolet absorber are the same as in Example 1.

[0025] The preparation steps of the ABS resin-specific antioxidant are as follows: 100 g of talc powder and 50 g of magnesium oxide are weighed and added to a mixer. Under normal temperature conditions, the mixture is stirred and premixed at 300 r / min for 0.5 h to form a uniform composite functional core. While keeping the mixer closed, 500 g of antioxidant 1076 is added, the temperature is raised to 55 ℃, and stirring is continued at 300 r / min for 0.4 h to form a core-shell structured primary mixture. 200 g of antioxidant 618 and 150 g of microencapsulated ultraviolet absorber UV-531 are simultaneously added to the mixer, the temperature is further raised to 75 ℃, the stirring speed is increased to 400 r / min, and stirring is continued for 0.3 h to ensure that the components are fully dispersed and uniformly coated on the surface of the primary mixture, resulting in a homogeneous mixture. The resulting mixture is continuously conveyed to a twin-screw extruder via a screw conveyor. The barrel temperature is set to 90 °C and the screw speed is set to 80 r / min to fully melt and plasticize the material before extruding it into strips. Subsequently, the material is granulated by a pelletizing mechanism at a speed of 400 r / min and cooled to about 25 °C to obtain flat round composite antioxidant granules with a particle size of 2-4 mm, which is the ABS resin-specific antioxidant.

[0026] Example 4: The ABS resin-specific antioxidant comprises the following raw materials in parts by weight: 55 parts of antioxidant 1076, 20 parts of antioxidant 618, 10 parts of microencapsulated ultraviolet absorber UV-531, 10 parts of talc, and 5 parts of magnesium oxide. The preparation steps of the microencapsulated ultraviolet absorber are the same as in Example 1.

[0027] The preparation steps for the ABS resin-specific antioxidant are as follows: 100 g of talc powder and 50 g of magnesium oxide are added to a mixer and stirred at 300 r / min for 0.5 hours at room temperature to ensure thorough and uniform mixing, forming a composite functional core. 550 g of antioxidant 1076 is added to the mixer and stirred at 300 r / min for 0.3 hours at 50℃ to form a primary mixture with a core-shell structure. 200 g of antioxidant 618 and 100 g of microencapsulated UV absorber UV-531 are added to the mixer, the temperature is raised to 70℃, the stirring speed is increased to 400 r / min, and stirring is continued for 0.2 hours to finally form a homogeneous mixture. The mixture is fed into a twin-screw extruder via a auger conveyor, with the barrel temperature set to 90℃ and the screw speed set to 80 r / min for melt plasticization. After extrusion through the die, the mixture is pelletized at 400 r / min to a particle size of 2–4 mm. Finally, the product is cooled to 25°C using an air-cooling device.

[0028] Example 5: The ABS resin-specific antioxidant comprises the following raw materials in parts by weight: 50 parts of antioxidant 1010, 20 parts of antioxidant 626, 10 parts of microencapsulated ultraviolet absorber UV-326, 10 parts of diatomaceous earth, and 5 parts of calcium oxide. The preparation steps of the microencapsulated ultraviolet absorber are the same as in Example 1.

[0029] The preparation steps of the ABS resin-specific antioxidant are as follows: 100 g of diatomaceous earth and 50 g of calcium oxide are added to a mixer and stirred at 300 r / min for 0.5 hours at room temperature to ensure uniform mixing and form a composite functional core. 500 g of antioxidant 1010 is added to the mixer, the temperature is raised to 50℃, and stirring continues for 0.3 hours (stirring speed 300 r / min) to form a primary mixture with a core-shell structure. 200 g of antioxidant 626 and 150 g of microencapsulated UV absorber UV-326 are simultaneously added to the mixer, the temperature is raised to 70℃, the stirring speed is increased to 400 r / min, and stirring continues for 0.2 hours to obtain a homogeneous mixture. The resulting mixture is continuously conveyed to a twin-screw extruder via a auger conveyor. The barrel temperature is set to 90℃ and the screw speed to 80 r / min for melt plasticization. After extrusion through the die, the pelletizing speed is set to 400 r / min, and the pellet diameter is approximately 2–4 mm. Finally, the particles were cooled to 25°C using an air-cooling system to obtain the ABS resin-specific antioxidant.

[0030] Example 6: The ABS resin-specific antioxidant comprises the following raw materials in parts by weight: 45 parts of antioxidant 1010, 20 parts of antioxidant 626, 10 parts of microencapsulated ultraviolet absorber UV-326, 10 parts of diatomaceous earth, and 5 parts of calcium oxide. The preparation steps of the microencapsulated ultraviolet absorber are the same as in Example 1.

[0031] The preparation steps for the ABS resin-specific antioxidant are as follows: Add 100 g of diatomaceous earth and 50 g of calcium oxide to a mixer and stir at 300 r / min for 0.5 hours at room temperature to ensure thorough mixing and form a uniform composite functional core. Add 450 g of antioxidant 1010 to the mixer, heat to 50℃, and continue stirring for 0.3 hours at 300 r / min to ensure that antioxidant 1010 is uniformly adsorbed onto the surface of the composite functional core, forming a primary mixture with a core-shell structure. Add 200 g of antioxidant 626 and 200 g of UV absorber UV-326 simultaneously to the mixer, heat to 70℃, increase the stirring speed to 400 r / min, and continue stirring for 0.2 hours to ensure uniform dispersion of all components and form a homogeneous mixture. Transport the mixture to a twin-screw extruder via a auger conveyor, setting the barrel temperature to 90℃ and the screw speed to 80 r / min for melt plasticizing. After extrusion through the die, the pelletizing speed is set to 400 r / min to cut the material into pellets with a size of 2-4 mm. Finally, the pellets are cooled to 25°C using an air-cooling system to obtain the ABS resin-specific antioxidant.

[0032] Example 7: The ABS resin-specific antioxidant comprises the following raw materials in parts by weight: antioxidant 245 50 parts, antioxidant 626 20 parts, microencapsulated ultraviolet absorber UV-327 15 parts, zeolite powder 10 parts, and magnesium oxide 5 parts. The preparation steps of the microencapsulated ultraviolet absorber are the same as in Example 1.

[0033] The preparation steps of the ABS resin-specific antioxidant are as follows: 100 g of zeolite powder and 50 g of magnesium oxide are added to a mixer and stirred at 300 r / min for 0.5 hours at room temperature to ensure thorough mixing and obtain a composite functional core. 500 g of antioxidant 245 is added to the mixer, the temperature is raised to 50℃, and the mixture is stirred at 300 r / min for 0.3 hours to form a primary mixture with a core-shell structure. 200 g of antioxidant 626 and 150 g of microencapsulated UV absorber UV-327 are simultaneously added to the mixer, the temperature is raised to 70℃, the stirring speed is increased to 400 r / min, and stirring is continued for 0.2 hours to ensure thorough dispersion of all components and obtain a homogeneous mixture. The resulting mixture is continuously conveyed to a twin-screw extruder via a auger conveyor, with the barrel temperature set to 90℃ and the screw speed to 80 r / min for melt plasticization. After extrusion through a die, the pelletizing speed is set to 400 r / min to cut the mixture into flat, round particles with a diameter of 2–4 mm. Finally, the particles are cooled to 25°C using an air-cooling system to obtain the ABS resin-specific antioxidant.

[0034] Example 8: The ABS resin-specific antioxidant comprises the following raw materials in parts by weight: 45 parts antioxidant 245, 20 parts antioxidant 626, 20 parts microencapsulated ultraviolet absorber UV-327, 10 parts zeolite powder, and 5 parts magnesium oxide. The preparation steps of the microencapsulated ultraviolet absorber are the same as in Example 1.

[0035] The preparation steps of the ABS resin-specific antioxidant are as follows: 100 g of zeolite powder and 50 g of magnesium oxide are added to a mixer and stirred at 300 r / min for 0.5 hours at room temperature to ensure uniform mixing of the two inorganic components and the formation of a composite functional core. 450 g of antioxidant 245 is added to the mixer and stirred at 50℃ for 0.3 hours (stirring speed of 300 r / min) to allow antioxidant 245 to be fully adsorbed onto the surface of the composite functional core, forming a core-shell structured primary mixture. 200 g of antioxidant 626 and 200 g of microencapsulated UV absorber UV-327 are added to the mixer, the temperature is raised to 70℃, the stirring speed is increased to 400 r / min, and stirring is continued for 0.2 hours to ensure uniform dispersion and coating of all components on the surface of the primary mixture, resulting in a homogeneous mixture. The mixture is continuously conveyed to a twin-screw extruder via a auger conveyor, with the barrel temperature set to 90℃ and the screw speed to 80 r / min for melt plasticization. After extrusion through a die, the pelletizing speed is set to 400 r / min for pellet cutting, resulting in a final pellet size of approximately 2–4 mm. The pellets are then cooled to 25°C using an air-cooling system to obtain the ABS resin-specific antioxidant.

[0036] Comparative Example 1: The ABS resin-specific antioxidant contains the following raw materials in parts by weight: 50 parts antioxidant 1076, 20 parts antioxidant 168, 10 parts silica, and 5 parts alumina; The preparation steps of the ABS resin-specific antioxidant are the same as those in Example 1, except that microencapsulated UV absorbers are not added.

[0037] Comparative Example 2: The ABS resin-specific antioxidant contains the following raw materials in parts by weight: 50 parts of antioxidant 1076, 20 parts of antioxidant 168, 15 parts of microencapsulated ultraviolet absorber UV-531, and 15 parts of talc. The preparation steps of the microencapsulated ultraviolet absorber are the same as in Example 1.

[0038] The preparation steps of the ABS resin-specific antioxidant are the same as in Example 1, except that 10 parts of silica and 5 parts of alumina are replaced with 15 parts of talc.

[0039] Performance testing Application of ABS resin-specific antioxidants: The composite antioxidants prepared in Examples 1-8 and Comparative Examples 1-2, as well as conventional single-agent antioxidants 1010, 1076, 168, and 626, were added to ABS resin at a dosage of 0.3%. The ABS resin was extruded and thermoplasticized into sheets for yellowing index testing. The test results are shown in Table 1 below.

[0040] Table 1 Results of Antioxidant Application Performance Tests (Yellowing Index)

[0041] As shown in Table 1, the ABS resin-specific antioxidants of the present invention have significant advantages compared with traditional single-agent antioxidants. In the yellowing index tests at 1 day and 30 days, the yellowing indices of Examples 1 to 8 were generally low, demonstrating excellent anti-yellowing performance, especially after 30 days. For example, the yellowing indices of Example 1 were 0.11 and 0.12, respectively, significantly lower than those of conventional antioxidants 1010 (1.38 / 2.55) and 1076 (1.46 / 2.63), showing stronger antioxidant capacity and color retention. In contrast, traditional antioxidants such as 168 (2.57 / 3.26) and 626 (2.43 / 3.84) exhibited higher yellowing indices, indicating poorer antioxidant effects. Although Comparative Examples 1 and 2 also have certain antioxidant effects, their yellowing index is still significantly higher than that of the Example. In particular, in the test after 30 days, the yellowing index of Comparative Examples 1 (0.73 / 0.76) and Comparative Examples 2 (0.45 / 0.48) is higher, which further proves the excellent stability of the composite antioxidant of the present invention in long-term use.

[0042] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] The foregoing has shown and described 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. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. An antioxidant specifically for ABS resin, characterized in that, It contains the following raw materials in parts by weight: 30-60 parts of primary antioxidant, 10-30 parts of secondary antioxidant, 10-25 parts of microencapsulated ultraviolet absorber, and 10-25 parts of dispersant protectant; The primary antioxidant is a hindered phenolic antioxidant; the secondary antioxidant is a phosphite antioxidant; the microencapsulated UV absorber is prepared by microencapsulation modification of a UV absorber through in-situ polymerization; and the dispersant is composed of a first component and a second component mixed in a weight ratio of 2:

1.

2. The ABS resin-specific antioxidant according to claim 1, characterized in that, The hindered phenolic antioxidant is selected from one or more of antioxidant 1010, antioxidant 1076, antioxidant 245, and antioxidant 300; the phosphite antioxidant is selected from one or more of antioxidant 168, antioxidant 626, and antioxidant 618.

3. The ABS resin-specific antioxidant according to claim 1, characterized in that, The ultraviolet absorber is selected from one or more of ultraviolet absorbers UV-531, UV-326, and UV-327; the microencapsulated modified wall material is a styrene-acrylonitrile copolymer; and the particle size of the microencapsulated ultraviolet absorber is 1–3 μm.

4. The ABS resin-specific antioxidant according to claim 1, characterized in that, The first component of the dispersant is selected from one or more of silica, talc, diatomaceous earth, and zeolite; the second component of the dispersant is selected from one or more of calcium oxide, aluminum oxide, and magnesium oxide.

5. The ABS resin-specific antioxidant according to claim 1, characterized in that, The microencapsulated ultraviolet absorber is prepared by the following method: the ultraviolet absorber is dispersed in deionized water, styrene-acrylonitrile copolymer monomer and initiator are added, and in-situ polymerization reaction is carried out under stirring conditions. After the reaction is completed, the microencapsulated ultraviolet absorber is obtained by centrifugation, drying and sieving to obtain a particle size of 1-3 μm.

6. The ABS resin-specific antioxidant according to claim 5, characterized in that, The in-situ polymerization reaction is carried out at a temperature of 60–80 °C for 2–4 h, and the initiator is potassium persulfate.

7. A method for preparing an ABS resin-specific antioxidant as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Weigh the first and second components of the dispersant and protective agent, add them to the mixer, premix and stir at room temperature until uniformly mixed to form a composite functional core; S2. Keep the mixing container closed, add the main antioxidant, and continue stirring to form a primary mixture with a core-shell structure; S3. Add auxiliary antioxidant and microencapsulated ultraviolet absorber to the mixer and continue stirring to obtain a homogeneous mixture; S4. The mixture is continuously conveyed to the granulator via an auger conveyor. After melting, plasticizing, extrusion, pelletizing and cooling processes, ABS resin-specific antioxidant is obtained.

8. The method for preparing the ABS resin-specific antioxidant according to claim 7, characterized in that, The stirring temperature in step S1 is 20-30℃ and the stirring time is 0.4-0.6 hours; the stirring temperature in step S2 is 45-55℃ and the stirring time is 0.2-0.4 hours; the stirring temperature in step S3 is 65-75℃ and the stirring time is 0.1-0.3 hours.

9. The method for preparing the ABS resin-specific antioxidant according to claim 7, characterized in that, In step S4, the granulation temperature of the granulator is 80-100℃, the pelletizing speed is 300-500 r / min, and the cooling process adopts air cooling with a cooling temperature of 25-30℃.

10. The application of a special antioxidant for ABS resin, characterized in that, The antioxidant is the ABS resin-specific antioxidant according to any one of claims 1 to 6, used to improve the thermal oxidation stability and anti-yellowing properties of ABS resin.

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