ASA material of a multilayer structure and a method for producing the same

Abstract

This invention discloses a multilayered ASA material and its preparation method, belonging to the field of resin preparation technology. The technical solution includes a rubber core, a mantle layer, and a shell layer; the rubber core is a copolymer elastomer formed by copolymerization and crosslinking of butyl acrylate and hard segment monomers; the mantle layer, which surrounds the outer surface of the rubber core, is polymerized from acrylate monomers; the shell layer, which surrounds the outer surface of the mantle layer, is graft copolymerized from styrene, methyl methacrylate, and acrylonitrile; the mass ratio of the rubber core, mantle layer, and shell layer is 1-4:2-8:1-5. The ASA material provided by this invention not only has good impact resistance but also good dyeability.

Description

Technical Field

[0001] This invention belongs to the field of resin preparation technology, and particularly relates to a multilayer ASA material and its preparation method. Background Technology

[0002] Acrylonitrile-styrene-acrylate copolymer (ASA) is an engineering plastic with several advantages in impact resistance compared to other common impact-resistant materials. Compared to its main competitors (such as ABS, PC, PMMA, and PVC), ASA's core advantage is its superior weather resistance, which includes the following advantages: 1. Strong UV resistance: The acrylate in the ASA molecular chain replaces the butadiene in ABS, eliminating the unstable double bond structure, thus making it less susceptible to UV degradation. With long-term outdoor use (5-10 years or more), its color and mechanical properties remain stable, while ABS is prone to yellowing and embrittlement outdoors.

[0003] 2. Resistant to weathering and suitable for outdoor applications (such as automotive exteriors, outdoor appliances, solar panel housings, etc.). It can be used for a long time without the need for UV-resistant additives, thus reducing costs.

[0004] 3. ASA offers a balanced overall performance. Its room temperature impact strength is comparable to ABS and superior to PMMA and PVC. It maintains good toughness even at low temperatures (-20℃ to -30℃). Molded products exhibit high surface gloss and are less prone to loss of gloss or discoloration with long-term outdoor use, surpassing ABS and untreated PC. It can also be directly injection molded without the need for an additional protective coating like ABS. Furthermore, it possesses excellent chemical stability and corrosion resistance.

[0005] Currently, the traditional method for manufacturing ASA involves first synthesizing a cross-linked polyacrylate emulsion, and then grafting a styrene-acrylonitrile polymer onto it, resulting in a two-layer core-shell structure. Patent CN113637115B, for example, yields an ASA material with this two-layer core-shell structure. However, traditional ASA materials generally suffer from the drawback of balancing impact resistance and dyeability. Larger ASA particles offer better impact resistance but poorer dyeability; conversely, smaller particles offer better dyeability but poorer impact resistance, highlighting the difficulty in achieving a balance between the two.

[0006] Currently, when people use acrylate as a rubber core to prepare impact-resistant materials, in order to balance impact resistance and dyeing properties, they often use a combination of different particle sizes to achieve a performance balance. However, this method is mostly complex in polymerization process, and in large-scale production, it is inefficient and wastes a lot of resources. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a multi-layered ASA material and its preparation method. The ASA material provided by this invention not only has good impact resistance but also good dyeability.

[0008] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows: This invention provides a multi-layered ASA material, comprising a rubber core, a mantle layer, and a shell layer; The rubber core is a copolymer elastomer formed by copolymerization and crosslinking of butyl acrylate and hard segment monomers; The mantle layer, which wraps around the outer surface of the rubber core, is polymerized from acrylate monomers. The shell layer, which wraps around the outer surface of the mantle layer, is composed of styrene, methyl methacrylate, and acrylonitrile graft copolymer. The hard segment monomer is one or two of hydroxyethyl acrylate, glycidyl methacrylate, methyl methacrylate, ethyl methacrylate, styrene and methylstyrene. The particle size of the rubber core is 30-150 nm; the particle size of the mantle layer is 80-200 nm; and the particle size of the shell layer is 150-300 nm. The mass ratio of the rubber core, mantle, and shell is 1-4:2-8:1-5; The crosslinking agent used for crosslinking is 1-5% of the weight of the reactant monomer; the crosslinking agent is divinylbenzene, ethylene glycol diglycidyl ether, dicyclopentadiene acrylate, allyl methacrylate, hexamethoxymethyl melamine resin, dimethacrylate or diallyl compound.

[0009] Preferably, the weight ratio of butyl acrylate to hard segment monomer raw material added during the synthesis of the rubber core is 1.5-5:1.

[0010] Preferably, the mass ratio of styrene, acrylonitrile, and methyl methacrylate is 50-70:15-40:5-15.

[0011] This invention provides a method for preparing the multilayer ASA material as described in any one of the above claims, comprising the following steps: 1) The butyl acrylate, hard segment monomer, crosslinking agent, emulsifier, chain transfer agent, reducing agent, catalyst and chelating agent are mixed and then pre-emulsified to obtain a pre-emulsion; 2) After adjusting the temperature of the pre-emulsion obtained above to 45-75℃, mix it with the initiator to react, so that the monomer conversion rate reaches more than 90%, and obtain the rubber core emulsion. 3) Adjust the temperature of the rubber core emulsion obtained above to 65-86℃, and add acrylate monomers and initiator solutions dropwise to react. The monomer conversion rate reaches more than 98%, and a rubber emulsion with a mantle layer is obtained. 4) Mix the rubber latex, catalyst and chelating agent of the above-mentioned mantle layer, adjust the temperature to 35-75℃, add the pre-emulsion and initiator dropwise to react and obtain ASA latex; The pre-emulsion is obtained by mixing deionized water, styrene, methyl methacrylate, acrylonitrile, reducing agent and emulsifier.

[0012] Preferably, in step 3), the initiator is added for a longer time than the acrylate monomer, and for more than 20 minutes.

[0013] Preferably, in step 4), the initiator is added for a longer time than the pre-emulsion, and for more than 40 minutes.

[0014] Preferably, the reaction time in step 2) is 5-12 hours.

[0015] Preferably, the reaction time in step 3) is 1-6 hours.

[0016] Preferably, the reaction time in step 4) is 2-8 hours.

[0017] Preferably, after obtaining ASA latex in step 4), the process further includes slowly adding the ASA latex to a flocculant aqueous solution while stirring, filtering, and drying to obtain ASA powder.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides an ASA material with a core-mantle-shell three-layer structure. It uses butyl acrylate and hard segment monomers as raw materials, which are highly cross-linked to form a relatively compact copolymer elastomer as the rubber core. Then, an acrylate monomer is polymerized and moderately cross-linked to prepare a mantle layer that wraps around the outer surface of the rubber core, thus forming a relatively hard elastomer core. The core and mantle layer structure work synergistically, resulting in better impact resistance compared to traditional butyl acrylate rubber. Furthermore, this combination effectively reduces the rubber particle size, further improving dyeing performance. The introduction of methyl methacrylate during the grafting process improves the surface smoothness and compatibility with materials such as PC, effectively balancing the product's impact and dyeing properties. Simultaneously, by controlling the ratio of the core, mantle, and shell, a suitable proportion of high-hardness core provides a hard support for impact resistance, while a certain proportion of buffering mantle structure further increases the impact resistance of the rubber phase (a higher proportion will reduce impact resistance). At the same time, a suitable proportion of shell structure minimizes the product particle size while ensuring impact performance, optimizing both impact resistance and dyeability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the multilayer ASA material prepared according to the present invention. Detailed Implementation

[0020] The technical solutions in specific embodiments of the present invention will be described in detail and completely below. Obviously, the described embodiments are only some specific implementations of the overall technical solution of the present invention, and not all implementations. Based on the overall concept of the present invention, all other embodiments obtained by those skilled in the art fall within the protection scope of the present invention.

[0021] This invention provides a multi-layered ASA material, comprising a rubber core, a mantle layer, and a shell layer; The rubber core is a copolymer elastomer formed by copolymerization and crosslinking of butyl acrylate and hard segment monomers; The mantle layer, which wraps around the outer surface of the rubber core, is polymerized from acrylate monomers. The shell layer, which wraps around the outer surface of the mantle layer, is composed of styrene, methyl methacrylate, and acrylonitrile graft copolymer. The hard segment monomer is one or two of hydroxyethyl acrylate, glycidyl methacrylate, methyl methacrylate, ethyl methacrylate, styrene and methylstyrene. The particle size of the rubber core is 30-150 nm; the particle size of the mantle layer is 80-200 nm; and the particle size of the shell layer is 150-300 nm. The mass ratio of the rubber core, mantle, and shell is 1-4:2-8:1-5; The crosslinking agent used for crosslinking is 1-5% of the weight of the reactant monomer; the crosslinking agent is divinylbenzene, ethylene glycol diglycidyl ether, dicyclopentadiene acrylate, allyl methacrylate, hexamethoxymethyl melamine resin, dimethacrylate or diallyl compound.

[0022] The ASA material provided by this invention has a core-mantle-shell three-layer structure, as shown in the schematic diagram below. Figure 1As shown, butyl acrylate and hard segment monomers are used as raw materials, and their high cross-linking forms a copolymer elastomer as the rubber core, effectively improving the core hardness and resulting in better impact resistance compared to traditional butyl acrylate rubber. Then, acrylate monomers are polymerized and moderately cross-linked to prepare a mantle layer that wraps around the outer surface of the rubber core, forming a relatively hard elastomer core. The synergistic effect of the core and mantle layer structure further enhances impact resistance compared to traditional butyl acrylate rubber. Furthermore, this combination effectively reduces the rubber particle size, further improving the dyeing effect. The introduction of methyl methacrylate during the grafting process improves the surface smoothness of the product and its compatibility with materials such as PC, effectively balancing the product's impact and dyeing properties. Simultaneously, by controlling the ratio of the core, mantle, and shell, an appropriate proportion of high-hardness core provides a hard support for impact resistance, while a suitable buffer mantle layer structure further increases the impact resistance of the rubber phase (a higher proportion will reduce impact resistance). At the same time, a suitable proportion of shell structure minimizes the product particle size while ensuring impact performance, optimizing both impact and dyeability.

[0023] In this invention, the hard segment monomer is one or two of hydroxyethyl acrylate, glycidyl methacrylate, methyl methacrylate, ethyl methacrylate, styrene, and methylstyrene. Using these hard segment monomers in this invention helps improve the hardness of the individual acrylate rubber core, enhances the product's support capacity, and improves its impact resistance.

[0024] In this invention, the preferred weight ratio of butyl acrylate to hard segment monomer raw materials during the synthesis of the rubber core is 1.5-5:1. Controlling the weight ratio of butyl acrylate to hard segment monomer within this range helps maintain better toughness while providing support, thus improving impact performance.

[0025] In this invention, the particle size of the rubber core is 30-150 nm; the particle size of the mantle layer is 80-200 nm; and the particle size of the shell layer is 150-300 nm. By controlling the particle sizes of the core, mantle, and shell layers within these ranges, this invention achieves higher impact resistance and better dyeing performance within a smaller particle size range.

[0026] In this invention, the crosslinking agent used for crosslinking is 1-5% of the weight of the reactant monomer. In this invention, controlling the crosslinking agent within the above range is beneficial for regulating the molecular structure and balancing the hardness and toughness of the material.

[0027] This invention provides a method for preparing the multilayer ASA material as described in any one of the above claims, comprising the following steps: 1) The butyl acrylate, hard segment monomer, crosslinking agent, emulsifier, chain transfer agent, reducing agent, catalyst and chelating agent are mixed and then pre-emulsified to obtain a pre-emulsion; 2) After adjusting the temperature of the pre-emulsion obtained above to 45-75℃, mix it with the initiator to react, so that the monomer conversion rate reaches more than 90%, and obtain the rubber core emulsion. 3) Adjust the temperature of the rubber core emulsion obtained above to 65-86℃, and add acrylate monomers and initiator solutions dropwise to react. The monomer conversion rate reaches more than 98%, and a rubber emulsion with a mantle layer is obtained. 4) Mix the rubber latex, catalyst and chelating agent of the above-mentioned mantle layer, adjust the temperature to 35-75℃, add the pre-emulsion and initiator dropwise to react and obtain ASA latex; The pre-emulsion is obtained by mixing deionized water, styrene, methyl methacrylate, acrylonitrile, reducing agent and emulsifier.

[0028] This invention involves pre-emulsifying a mixture of butyl acrylate, hard segment monomers, crosslinking agents, emulsifiers, chain transfer agents, reducing agents, catalysts, and chelating agents to obtain a pre-emulsion. In this invention, the crosslinking agent is preferably divinylbenzene, ethylene glycol diglycidyl ether, dicyclopentadiene acrylate, allyl methacrylate, hexamethoxymethyl melamine resin, dimethacrylate, or diallyl compounds. In this invention, the diallyl compound is preferably allyl dimethyl ammonium chloride or diallylamine. In this invention, the crosslinking agent is preferably 1-5% of the weight of the reactant monomers. In this invention, controlling the crosslinking agent within the above range is beneficial for regulating the molecular structure and balancing the hardness and toughness of the material. In this invention, the emulsifier is preferably an anionic emulsifier. In this invention, the anionic emulsifier is preferably one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium dodecyl sulfate, potassium oleate, potassium stearate, and potassium disproportionated rosinate. In this invention, the amount of emulsifier added is preferably 4-15% of the mass of the polymerizable monomer. Controlling the emulsifier within this range allows for better control of product particle size and stability, and improves the product's impact resistance. In this invention, the chain transfer agent is preferably n-dodecyl mercaptan and / or tert-dodecyl mercaptan. The amount of chain transfer agent added is preferably 0.1-0.8% of the mass of the polymerizable monomer. In this invention, the reducing agent is preferably one or more of sodium formaldehyde bisulfite, sodium bisulfite, and sodium sulfite. The amount of reducing agent added is preferably 0.01-0.3% of the mass of the polymerizable monomer. In this invention, the catalyst is preferably an ionic compound containing copper, iron, cobalt, or manganese ions. The amount of catalyst added is preferably 0.03-0.3% of the mass of the polymerizable monomer. In this invention, the chelating agent is preferably one or more of diethylenetriaminepentaacetic acid, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, hydroxyethylidene diphosphonic acid, and sodium citrate; the amount of the chelating agent added is preferably 0.02-0.2% of the relative mass of the polymerizing monomer.

[0029] After obtaining the pre-emulsion, the present invention adjusts the temperature of the pre-emulsion to 45-75℃ and mixes it with an initiator to react, so that the monomer conversion rate reaches more than 90%, thereby obtaining a rubber core emulsion. In the present invention, the initiator is preferably one or more of potassium persulfate, ammonium persulfate, cumene hydroperoxide, and tert-butyl peroxide. In the present invention, the amount of initiator added is preferably 0.02-0.2% of the relative mass of the polymerizing monomer. In the present invention, the reaction vessel is first purged with nitrogen to remove oxygen before the pre-emulsion and initiator are placed in the reaction vessel and mixed for reaction. In the present invention, the reaction time is preferably 5-12 hours.

[0030] After obtaining the rubber core emulsion, the present invention adjusts the temperature of the obtained rubber core emulsion to 65-86℃, and adds acrylate monomers and initiator solutions dropwise to react. The monomer conversion rate reaches over 98%, resulting in a rubber emulsion with a mantle layer. In the present invention, the acrylate monomers are preferably methyl acrylate, ethyl acrylate, butyl acrylate, hydroxypropyl acrylate, tert-butyl acrylate, methyl methacrylate, ethyl methacrylate, or methyl methacrylate, more preferably butyl acrylate. In the present invention, the initiator is preferably one or more of potassium persulfate, ammonium persulfate, cumene hydroperoxide, and tert-butyl peroxide. In the present invention, the amount of initiator added is preferably 0.04-0.2% of the relative mass of the polymerizing monomer. In the present invention, the dropwise addition time of the initiator is preferably longer than the dropwise addition time of the acrylate monomer, preferably longer than 20 min, more preferably 30-70 min. In the present invention, controlling the dropwise addition time of the initiator to be longer than the dropwise addition time of the acrylate monomer, and longer than 20 min, is beneficial for the stability control of particle size. In this invention, the reaction time is preferably 1-6 hours.

[0031] After obtaining the rubber latex with a mantle layer, this invention mixes the rubber latex with the mantle layer, a catalyst, and a chelating agent, adjusts the temperature to 35-75°C, and adds a pre-emulsion and an initiator dropwise to react and obtain ASA latex. In this invention, the catalyst is preferably an ionic compound containing copper, iron, cobalt, or manganese ions. In this invention, the amount of catalyst added is preferably 0.03-0.3% of the mass of the polymerizable monomer. In this invention, the chelating agent is preferably one or more of diethylenetriaminepentaacetate, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, hydroxyethylidene diphosphonic acid, and sodium citrate; the amount of chelating agent added is preferably 0.02-0.2% of the mass of the polymerizable monomer. In this invention, the pre-emulsion is obtained by mixing deionized water, styrene, methyl methacrylate, acrylonitrile, a reducing agent, and an emulsifier. In this invention, the reducing agent is preferably one or more of sodium formaldehyde sulfoxylate, sodium bisulfite, and sodium sulfite. In this invention, the amount of reducing agent added is preferably 0.01-0.3% of the mass of the polymeric monomer. In this invention, the emulsifier is preferably an anionic emulsifier; the anionic emulsifier is preferably one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium dodecyl sulfate, potassium oleate, potassium stearate, and potassium disproportionated rosinate. In this invention, the amount of emulsifier added is preferably 4-15% of the mass of the polymeric monomer. In this invention, when preparing the shell layer, the mass ratio of styrene, acrylonitrile, and methyl methacrylate is preferably 50-70:15-40:5-15. In this invention, by controlling the mass ratio of styrene, acrylonitrile, and methyl methacrylate within the above range, it is beneficial to maintain the dyeability of the product and its compatibility with alloy materials such as PC while controlling a suitable grafting rate. In this invention, the initiator dropping time is preferably longer than the pre-emulsion dropping time, and more preferably 40-70 minutes. In this invention, controlling the dropwise addition time of the initiator to be longer than the dropwise addition time of the acrylate monomer, and exceeding 40 minutes, is beneficial for controlling the reaction rate and improving the grafting rate and molecular weight control. In this invention, the reaction time is preferably 2-8 hours.

[0032] In this invention, the reactant monomers are added all at once during the core polymerization process, continuously added dropwise during the mantle synthesis process, and continuously or intermittently added during the shell grafting process. This method can effectively control the size and uniformity of the particle size.

[0033] In this invention, after obtaining ASA latex, the process further includes slowly adding the ASA latex to a flocculant aqueous solution while stirring, filtering, and then drying to obtain ASA powder. In this invention, the mass concentration of the flocculant aqueous solution is preferably 5%-20%, and the flocculant is preferably an acid or salt; the acid is preferably one or more of sulfuric acid, hydrochloric acid, and acetic acid. This invention does not specifically limit the type of salt; it can be sodium chloride, calcium chloride, magnesium chloride, sodium sulfate, magnesium sulfate, and other commonly used salts. In this invention, the drying temperature is preferably controlled at 50-90℃.

[0034] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0035] Example 1 Rubber nucleus synthesis stage: 200 parts deionized water, 40 parts butyl acrylate, 20 parts methyl methacrylate, 1.8 parts allyl methacrylate (crosslinking agent), 1.5 parts potassium oleate (emulsifier), 2 parts sodium dodecyl sulfate (emulsifier), 0.2 parts tert-dodecyl mercaptan (chain transfer agent), 0.4 parts sodium formaldehyde sulfoxylate (reducing agent), 0.1 parts ferrous sulfate (catalyst), and 0.2 parts disodium ethylenediaminetetraacetate (chelating agent) were added to the polymerization reactor using a high-pressure pump. Stirring was started for pre-emulsification. The reactor was then purged three times with nitrogen to remove oxygen. Then, 1.2 parts of cumene hydroperoxide (initiator) solution was injected into the reactor. The temperature was initially raised to 73°C, and the reaction was continued for 5 hours to obtain rubber seed latex with a measured particle size of 75 nm.

[0036] Rubber mantle synthesis stage: Add 1.2 parts of sodium dodecyl sulfate (emulsifier) ​​to 90 parts of butyl acrylate to obtain a butyl acrylate solution. Add 1.2 parts of cumene hydroperoxide to 50 parts of water and mix thoroughly to obtain an initiator solution. Add 150 parts of the above seed emulsion to reactor 2, control the reaction temperature at 65℃, and add the above butyl acrylate solution and initiator solution dropwise using a constant flow pump. The butyl acrylate solution is added over 3 hours, and the initiator solution is added over 3.5 hours, resulting in a rubber emulsion with a mantle layer. The particle size was measured to be 180 nm.

[0037] Grafting stage: Grafting monomer and emulsion preparation: Add 46 parts styrene, 25 parts acrylonitrile, 5 parts methyl methacrylate, 0.8 parts sodium dodecylbenzenesulfonate, and 0.4 parts sodium formaldehyde sulfoxylate (reducing agent) to 80 parts deionized water, and stir for 30 minutes until the emulsion is stable to obtain a pre-emulsion.

[0038] 0.16 parts of ferrous sulfate (catalyst) and 0.32 parts of disodium ethylenediaminetetraacetate (chelating agent) were added to 200 parts of rubber latex containing the mantle layer. Stirring was started for 15 minutes until the latex became homogeneous and did not separate into layers. Nitrogen gas was introduced while the temperature was raised to 55°C. The pre-emulsion was then added dropwise to the reactor over 4 hours. 1.5 parts of cumene hydroperoxide solution (initiator) was added over 5 hours to obtain an ASA latex with a measured particle size of 215 nm. The mass ratio of the rubber core, mantle layer, and shell layer was determined to be 1:1.2:0.35.

[0039] Flocculation stage: Prepare a 10% magnesium sulfate aqueous solution, and slowly add ASA emulsion to it while stirring. Then filter and dry at 85°C to obtain ASA powder.

[0040] Example 2 The difference from Example 1 is that the crosslinking agent added during the preparation of the rubber core is 1.5 parts allyl methacrylate and 0.5 parts divinylbenzene; all other operations are exactly the same as in Example 1. The resulting rubber seed emulsion latex has a particle size of 90 nm, the resulting rubber emulsion encapsulating the mantle layer has a particle size of 175 nm, and the final ASA emulsion has a particle size of 235 nm. The measured mass ratio of the rubber core, mantle layer, and shell layer is 1:1.05:0.32.

[0041] Example 3 The difference from Example 1 is that the crosslinking agent added during the preparation of the rubber core is 1.5 parts of allyl methacrylate. All other operations are exactly the same as in Example 1. The resulting rubber seed emulsion latex has a particle size of 85 nm, the resulting rubber emulsion encapsulating the mantle layer has a particle size of 180 nm, and the final ASA emulsion has a particle size of 229 nm. The measured mass ratio of the rubber core, mantle layer, and shell layer is 1:1.15:0.42.

[0042] Example 4 The difference from Example 1 is that the crosslinking agent added during the preparation of the rubber core is 3 parts dicyclopentadiene acrylate. All other operations are exactly the same as in Example 1. The resulting rubber seed emulsion latex has a particle size of 91 nm, the resulting rubber emulsion encapsulating the mantle layer has a particle size of 170 nm, and the final ASA emulsion has a particle size of 199 nm. The measured mass ratio of the rubber core, mantle layer, and shell layer is 1:1.1:0.36.

[0043] Example 5 The difference from Example 1 is that 55 parts of butyl acrylate and 20 parts of methyl methacrylate were added during the preparation of the rubber core; and 95 parts of butyl acrylate were added during the mantle synthesis. All other operations were exactly the same as in Example 1. The resulting rubber seed emulsion latex had a particle size of 78 nm, the resulting rubber emulsion encapsulating the mantle layer had a particle size of 168 nm, and the final ASA emulsion had a particle size of 256 nm. The measured mass ratio of the rubber core, mantle layer, and shell layer was 1:1.1:0.46.

[0044] Example 6 The difference from Example 1 is that 105 parts of butyl acrylate were added during the mantle synthesis stage; all other operations were exactly the same as in Example 1. The resulting rubber seed emulsion latex had a particle size of 78 nm, the resulting rubber emulsion encapsulating the mantle layer had a particle size of 184 nm, and the final ASA emulsion had a particle size of 220 nm. The mass ratio of the rubber core, mantle layer, and shell layer was measured to be 1:1.5:0.6.

[0045] Example 7 The difference from Example 1 is that 105 parts of butyl acrylate were added during the mantle synthesis stage; and 80 parts of styrene, 33 parts of acrylonitrile, and 5 parts of methyl methacrylate were added during the grafting stage. All other operations were exactly the same as in Example 1. The resulting rubber seed emulsion latex had a particle size of 76 nm, the resulting rubber emulsion encapsulating the mantle layer had a particle size of 184 nm, and the final ASA emulsion had a particle size of 234 nm. The mass ratio of the rubber core, mantle layer, and shell layer was measured to be 1:1.52:0.67.

[0046] Example 8 The difference from Example 1 is that 30 parts of butyl acrylate, 8 parts of hydroxyethyl acrylate, and 1.5 parts of hexamethoxymethyl melamine resin were added during the preparation of the rubber core. The final ASA emulsion had a particle size of 236 nm, and the mass ratio of the rubber core, mantle, and shell was measured to be 1:1.2:0.42.

[0047] The specific steps are as follows: Rubber nucleus synthesis stage: 200 parts deionized water, 30 parts butyl acrylate, 8 parts hydroxyethyl acrylate, 1.5 parts hexamethoxymethyl melamine resin (crosslinking agent), 1.5 parts potassium oleate (emulsifier), 2 parts sodium dodecyl sulfate (emulsifier), 0.2 parts tert-dodecyl mercaptan (chain transfer agent), 0.4 parts sodium formaldehyde sulfoxylate (reducing agent), 0.1 parts ferrous sulfate (catalyst), and 0.2 parts disodium ethylenediaminetetraacetate (chelating agent) were added to the polymerization reactor using a high-pressure pump. Stirring was started for pre-emulsification. The reactor was then purged three times with nitrogen to remove oxygen. Then, 1.2 parts of cumene hydroperoxide solution (initiator) was injected into the reactor. The temperature was initially raised to 55°C, and the reaction was continued for 12 hours to obtain rubber seed latex with a measured particle size of 78 nm.

[0048] Rubber mantle synthesis stage: Add 1.2 parts of sodium dodecyl sulfate (emulsifier) ​​to 90 parts of butyl acrylate to obtain a butyl acrylate solution. Add 1.2 parts of cumene hydroperoxide to 50 parts of water and mix thoroughly to obtain an initiator solution. Add 150 parts of the above seed emulsion to reactor 2, control the reaction temperature at 75℃, and add the above butyl acrylate solution and initiator solution dropwise using a constant flow pump. The butyl acrylate solution is added over 4 hours, and the initiator solution is added over 4.5 hours, resulting in a rubber emulsion with a mantle layer. The particle size was measured to be 165 nm.

[0049] Grafting stage: Grafting monomer and emulsion preparation: Add 46 parts styrene, 25 parts acrylonitrile, 5 parts methyl methacrylate, 0.8 parts sodium dodecylbenzenesulfonate, and 0.4 parts sodium formaldehyde sulfoxylate (reducing agent) to 80 parts deionized water, and stir for 30 minutes until the emulsion is stable to obtain a pre-emulsion.

[0050] 0.16 parts of ferrous sulfate (catalyst) and 0.32 parts of disodium ethylenediaminetetraacetate (chelating agent) were added to 200 parts of rubber latex containing the mantle layer. Stirring was started for 15 minutes until the latex became homogeneous and did not separate into layers. Nitrogen gas was introduced while the temperature was raised to 55°C. The pre-emulsion was then added dropwise to the reactor over 4 hours. 1.5 parts of cumene hydroperoxide solution (initiator) was added over 5 hours to obtain an ASA latex with a measured particle size of 236 nm. The mass ratio of the rubber core, mantle layer, and shell layer was determined to be 1:1.51:0.42.

[0051] Flocculation stage: Prepare a 10% magnesium sulfate aqueous solution, and slowly add ASA emulsion to it while stirring. Then filter and dry at 85°C to obtain ASA powder.

[0052] Example 9 The difference from Example 1 is that 30 parts of butyl acrylate were added during the preparation of the rubber core, 20 parts of glycidyl methacrylate monomer were added, and 1 part of ethylene glycol diglycidyl ether was added as the crosslinking agent; in the grafting stage, 70 parts of styrene, 40 parts of acrylonitrile, and 15 parts of methyl methacrylate were added. Other operations were exactly the same as in Example 1. The final ASA emulsion had a particle size of 256 nm, and the mass ratio of the rubber core, mantle, and shell was measured to be 1:1.3:0.56.

[0053] The specific steps are as follows: Rubber nucleus synthesis stage: 200 parts deionized water, 30 parts butyl acrylate, 20 parts glycidyl methacrylate, 1 part ethylene glycol diglycidyl ether (crosslinking agent), 1.5 parts potassium oleate (emulsifier), 2 parts sodium dodecyl sulfate (emulsifier), 0.2 parts tert-dodecyl mercaptan (chain transfer agent), 0.4 parts sodium formaldehyde sulfoxylate (reducing agent), 0.1 parts ferrous sulfate (catalyst), and 0.2 parts disodium ethylenediaminetetraacetate (chelating agent) were added to the polymerization reactor using a high-pressure pump. Stirring was started for pre-emulsification. The reactor was then purged three times with nitrogen to remove oxygen. Then, 1.2 parts of cumene hydroperoxide (initiator) solution was injected into the reactor. The temperature was initially raised to 50°C, and the reaction was continued for 12 hours to obtain rubber seed latex with a measured particle size of 103 nm.

[0054] Rubber mantle synthesis stage: Add 1.2 parts of sodium dodecyl sulfate (emulsifier) ​​to 90 parts of butyl acrylate to obtain a butyl acrylate solution. Add 1.2 parts of cumene hydroperoxide to 50 parts of water and mix thoroughly to obtain an initiator solution for later use. Add 150 parts of the above seed emulsion to reactor 2, control the reaction temperature at 80℃, and add the above butyl acrylate solution and initiator solution dropwise using a constant flow pump. The butyl acrylate solution is added over 2.5 hours, and the initiator solution is added over 3 hours, to obtain a rubber emulsion with a mantle layer, and the particle size is measured to be 190 nm.

[0055] Grafting stage: Grafting monomer and emulsion preparation: Add 70 parts styrene, 40 parts acrylonitrile, 15 parts methyl methacrylate, 0.8 parts sodium dodecylbenzenesulfonate, and 0.4 parts sodium formaldehyde sulfoxylate (reducing agent) to 80 parts deionized water, and stir for 30 minutes until the emulsion is stable to obtain a pre-emulsion.

[0056] 0.16 parts of ferrous sulfate (catalyst) and 0.32 parts of disodium ethylenediaminetetraacetate (chelating agent) were added to 200 parts of rubber latex containing the mantle layer. Stirring was started for 15 minutes until the latex became homogeneous and did not separate into layers. Nitrogen gas was introduced while the temperature was raised to 75°C. The pre-emulsion was then added dropwise to the reactor over 3 hours. 1.5 parts of cumene hydroperoxide solution (initiator) was added over 4 hours to obtain an ASA latex with a measured particle size of 255 nm. The mass ratio of the rubber core, mantle layer, and shell layer was determined to be 1:1.3:0.56.

[0057] Flocculation stage: Prepare a 10% magnesium sulfate aqueous solution, and slowly add ASA emulsion to it while stirring. Then filter and dry at 85°C to obtain ASA powder.

[0058] Example 10 The difference from Example 1 is that 30 parts of butyl acrylate were added during the preparation of the rubber core, and the hard segment monomers were: 5 parts of methyl propylene, 5 parts of styrene, and 1.2 parts of dimethacrylate as the crosslinking agent. In the grafting stage, 50 parts of styrene, 15 parts of acrylonitrile, and 5 parts of methyl methacrylate were added. Other operations were exactly the same as in Example 1. The final ASA emulsion had a particle size of 208 nm, and the mass ratio of the rubber core, mantle, and shell was measured to be 1:1.56:0.37.

[0059] The specific steps are as follows: Rubber nucleus synthesis stage: 200 parts deionized water, 30 parts butyl acrylate, 5 parts methyl propylene, 5 parts styrene, 1.2 parts dimethacrylate (crosslinking agent), 1.5 parts potassium oleate (emulsifier), 2 parts sodium dodecyl sulfate (emulsifier), 0.2 parts tert-dodecyl mercaptan (chain transfer agent), 0.4 parts sodium formaldehyde sulfoxylate (reducing agent), 0.1 parts ferrous sulfate (catalyst), and 0.2 parts disodium ethylenediaminetetraacetate (chelating agent) were added to the polymerization reactor using a high-pressure pump. Stirring was started for pre-emulsification. The reactor was then purged three times with nitrogen to remove oxygen. Then, 1.2 parts of cumene hydroperoxide solution (initiator) was injected into the reactor. The temperature was initially raised to 60°C, and the reaction was continued for 10 hours to obtain rubber seed latex with a measured particle size of 65 nm.

[0060] Rubber mantle synthesis stage: Add 1.2 parts of sodium dodecyl sulfate (emulsifier) ​​to 90 parts of butyl acrylate to obtain a butyl acrylate solution. Add 1.2 parts of cumene hydroperoxide to 50 parts of water and mix thoroughly to obtain an initiator solution. Add 150 parts of the above seed emulsion to reactor 2, control the reaction temperature at 65℃, and add the above butyl acrylate solution and initiator solution dropwise using a constant flow pump. The butyl acrylate solution is added over 5 hours, and the initiator solution is added over 6 hours, to obtain a rubber emulsion with a mantle layer. The particle size was measured to be 136 nm.

[0061] Grafting stage: Grafting monomer and emulsion preparation: Add 50 parts styrene, 15 parts acrylonitrile, 5 parts methyl methacrylate, 0.8 parts sodium dodecylbenzenesulfonate, and 0.4 parts sodium formaldehyde sulfoxylate (reducing agent) to 80 parts deionized water, and stir for 30 minutes until the emulsion is stable to obtain a pre-emulsion.

[0062] 0.16 parts of ferrous sulfate (catalyst) and 0.32 parts of disodium ethylenediaminetetraacetate (chelating agent) were added to 200 parts of rubber latex containing the mantle layer. Stirring was started for 15 minutes until the latex became homogeneous and did not separate into layers. Nitrogen gas was introduced while the temperature was raised to 40°C. The pre-emulsion was then added dropwise to the reactor over 7 hours. 1.5 parts of cumene hydroperoxide solution (initiator) was added over 8 hours to obtain an ASA latex with a measured particle size of 185 nm. The mass ratio of the rubber core, mantle layer, and shell layer was determined to be 1:1.56:0.37.

[0063] Flocculation stage: Prepare a 10% magnesium sulfate aqueous solution, and slowly add ASA emulsion to it while stirring. Then filter and dry at 85°C to obtain ASA powder.

[0064] Comparative Example 1 The difference from Example 1 is that in the nucleus synthesis stage, only the soft monomer butyl acrylate is used, without the addition of hard monomers. The specific preparation method includes the following steps: Rubber nucleus synthesis stage: 200 parts of deionized water, 60 parts of butyl acrylate, 1.8 parts of allyl methacrylate (crosslinking agent), 1.5 parts of potassium oleate (emulsifier), 2 parts of sodium dodecyl sulfate (emulsifier), 0.2 parts of tert-dodecyl mercaptan (chain transfer agent), 0.4 parts of sodium formaldehyde sulfoxylate (reducing agent), 0.1 parts of ferrous sulfate (co-catalyst), and 0.2 parts of disodium ethylenediaminetetraacetate (chelating agent) were added to the polymerization reactor using a high-pressure pump. Stirring was started for pre-emulsification. The reactor was then purged three times with nitrogen to remove oxygen. 1.2 parts of cumene hydroperoxide solution were then injected into the reactor. The temperature was initially raised to 73°C, and the reaction was continued for 5 hours to obtain rubber seed latex with a measured particle size of 118 nm.

[0065] Rubber mantle synthesis stage: Add 1.2 parts of sodium dodecyl sulfate (emulsifier) ​​to 90 parts of butyl acrylate to obtain a butyl acrylate solution. Add 1.2 parts of cumene hydroperoxide to 50 parts of water and mix thoroughly to obtain an initiator solution. Add 150 parts of the above seed emulsion to reactor 2, control the reaction temperature at 65℃, and add the above butyl acrylate solution and initiator solution dropwise using a constant flow pump. The butyl acrylate solution is added over 3 hours, and the initiator solution is added over 3.5 hours, resulting in a rubber emulsion with a mantle layer. The particle size was measured to be 216 nm.

[0066] Grafting stage: Grafting monomer and emulsion preparation: Add 46 parts styrene, 25 parts acrylonitrile, 5 parts methyl methacrylate, 0.8 parts sodium dodecylbenzenesulfonate, and 0.4 parts sodium formaldehyde sulfoxylate to 80 parts deionized water, stir for 30 minutes until the emulsion is stable, and obtain the pre-emulsion.

[0067] Add 0.16 parts of ferrous sulfate (catalyst) and 0.32 parts of disodium ethylenediaminetetraacetate (chelating agent) to 200 parts of rubber latex with a mantle layer. Stir for 15 minutes until the latex is homogeneous and does not separate into layers. While purging nitrogen gas, raise the temperature and control it at 55°C. Then, add the above pre-emulsion dropwise to the reactor. Continue adding the pre-emulsion dropwise for 4 hours. Add 1.5 parts of cumene hydroperoxide (initiator) solution dropwise for 5 hours to obtain an ASA latex with a particle size of 263 nm.

[0068] Flocculation stage: Prepare a 10% magnesium sulfate aqueous solution, and slowly add ASA emulsion to it while stirring. Then filter and dry at 85°C to obtain ASA powder.

[0069] Comparative Example 2 The difference from Example 1 is that 21 parts of butyl acrylate were added during the mantle synthesis stage, and 69 parts of styrene, 37.5 parts of acrylonitrile, and 7.5 parts of methyl methacrylate were added during the grafting stage. The mass ratio of the rubber core, mantle, and shell was measured to be 1:0.4:1.29.

[0070] Rubber nucleus synthesis stage: 200 parts deionized water, 40 parts butyl acrylate, 20 parts methyl methacrylate, 1.8 parts allyl methacrylate (crosslinking agent), 1.5 parts potassium oleate (emulsifier), 2 parts sodium dodecyl sulfate (emulsifier), 0.2 parts tert-dodecyl mercaptan (chain transfer agent), 0.4 parts sodium formaldehyde sulfoxylate (reducing agent), 0.1 parts ferrous sulfate (co-catalyst), and 0.2 parts disodium ethylenediaminetetraacetate (chelating agent) were added to the polymerization reactor using a high-pressure pump. Stirring was started for pre-emulsification. The reactor was then purged three times with nitrogen to remove oxygen. 1.2 parts of cumene hydroperoxide solution were then injected into the reactor. The temperature was initially raised to 73°C, and the reaction was continued for 5 hours to obtain rubber seed latex with a measured particle size of 75 nm.

[0071] Rubber mantle synthesis stage: Add 1.2 parts of sodium dodecyl sulfate (emulsifier) ​​to 21 parts of butyl acrylate to obtain a butyl acrylate solution. Add 1.2 parts of cumene hydroperoxide to 50 parts of water and mix thoroughly to obtain an initiator solution for later use. Add 150 parts of the above seed emulsion to reactor 2, control the reaction temperature at 65℃, and add the above butyl acrylate solution and initiator solution dropwise using a constant flow pump. The butyl acrylate solution is added over 3 hours, and the initiator solution is added over 3.5 hours, resulting in a rubber emulsion with a mantle layer. The particle size was measured to be 124 nm.

[0072] Grafting stage: Grafting monomer and emulsion preparation: Add 69 parts styrene, 37.5 parts acrylonitrile, 7.5 parts methyl methacrylate, 0.8 parts sodium dodecylbenzenesulfonate, and 0.4 parts sodium formaldehyde sulfoxylate to 80 parts deionized water, stir for 30 minutes until the emulsion is stable, and obtain the pre-emulsion.

[0073] 0.16 parts of ferrous sulfate (catalyst) and 0.32 parts of disodium ethylenediaminetetraacetate (chelating agent) were added to 200 parts of rubber latex containing the mantle layer. Stirring was started for 15 minutes until the latex became homogeneous and did not separate into layers. Nitrogen gas was introduced while the temperature was raised to 55°C. The pre-emulsion was then added dropwise to the reactor over 4 hours. 1.5 parts of cumene hydroperoxide solution (initiator) was added over 5 hours to obtain an ASA latex with a measured particle size of 188 nm. The mass ratio of the rubber core, mantle layer, and shell layer was determined to be 1:0.4:1.29.

[0074] Flocculation stage: Prepare a 10% magnesium sulfate aqueous solution, and slowly add ASA emulsion to it while stirring. Then filter and dry at 85°C to obtain ASA powder.

[0075] Comparative Example 3 The difference from Example 1 lies in the core synthesis stage, where 0.5 parts of potassium oleate and 1 part of sodium dodecyl sulfate were added as emulsifier. The measured core particle size of the above rubber was 260 nm, the mantle particle size was 550 nm, and the shell particle size was 620 nm. The specific operation is as follows: Rubber nucleus synthesis stage: 200 parts deionized water, 40 parts butyl acrylate, 20 parts methyl methacrylate, 1.8 parts allyl methacrylate (crosslinking agent), 0.5 parts potassium oleate (emulsifier), 1 part sodium dodecyl sulfate (emulsifier), 0.2 parts tert-dodecyl mercaptan (chain transfer agent), 0.4 parts sodium formaldehyde sulfoxylate (reducing agent), 0.1 parts ferrous sulfate (co-catalyst), and 0.2 parts disodium ethylenediaminetetraacetate (chelating agent) were added to the polymerization reactor using a high-pressure pump. Stirring was started for pre-emulsification. The reactor was then purged three times with nitrogen to remove oxygen. 1.2 parts of cumene hydroperoxide solution were then injected into the reactor. The temperature was initially raised to 73°C, and the reaction was continued for 5 hours to obtain rubber seed latex with a measured particle size of 260 nm.

[0076] Rubber mantle synthesis stage: Add 1.2 parts of sodium dodecyl sulfate (emulsifier) ​​to 90 parts of butyl acrylate to obtain a butyl acrylate solution. Add 1.2 parts of cumene hydroperoxide to 50 parts of water and mix thoroughly to obtain an initiator solution. Add 150 parts of the above seed emulsion to reactor 2, control the reaction temperature at 65℃, and add the above butyl acrylate solution and initiator solution dropwise using a constant flow pump. The butyl acrylate solution is added over 3 hours, and the initiator solution is added over 3.5 hours, resulting in a rubber emulsion with a mantle layer. The particle size was measured to be 550 nm.

[0077] Grafting stage: Grafting monomer and emulsion preparation: Add 46 parts styrene, 25 parts acrylonitrile, 5 parts methyl methacrylate, 0.8 parts sodium dodecylbenzenesulfonate, and 0.4 parts sodium formaldehyde sulfoxylate to 80 parts deionized water, stir for 30 minutes until the emulsion is stable, and obtain the pre-emulsion.

[0078] 0.16 parts of ferrous sulfate (catalyst) and 0.32 parts of disodium ethylenediaminetetraacetate (chelating agent) were added to 200 parts of rubber latex containing the mantle layer. Stirring was started for 15 minutes until the latex was homogeneous and did not separate into layers. Nitrogen gas was introduced while the temperature was raised to 55°C. The pre-emulsion was then added dropwise to the reactor over 4 hours. 1.5 parts of cumene hydroperoxide solution (initiator) was added over 5 hours to obtain an ASA latex with a measured particle size of 620 nm. The mass ratio of the rubber core, mantle layer, and shell layer was determined to be 1:1.1:0.5.

[0079] Flocculation stage: Prepare a 10% magnesium sulfate aqueous solution, and slowly add ASA emulsion to it while stirring. Then filter and dry at 85°C to obtain ASA powder.

[0080] Comparative Example 4 The difference from Example 1 lies in the rubber core preparation stage, where no crosslinking agent is added. The specific operation is as follows: Rubber nucleus synthesis stage: 200 parts deionized water, 40 parts butyl acrylate, 20 parts methyl methacrylate, 1.5 parts potassium oleate (emulsifier), 2 parts sodium dodecyl sulfate (emulsifier), 0.2 parts tert-dodecyl mercaptan (chain transfer agent), 0.4 parts sodium formaldehyde sulfoxylate (reducing agent), 0.1 parts ferrous sulfate (co-catalyst), and 0.2 parts disodium ethylenediaminetetraacetate (chelating agent) were added to the polymerization reactor using a high-pressure pump. Stirring was started for pre-emulsification. The reactor was then purged three times with nitrogen to remove oxygen. 1.2 parts of cumene hydroperoxide solution were then injected into the reactor. The temperature was initially raised to 73°C, and the reaction was continued for 5 hours to obtain rubber seed latex with a measured particle size of 88 nm.

[0081] Rubber mantle synthesis stage: Add 1.2 parts of sodium dodecyl sulfate (emulsifier) ​​to 90 parts of butyl acrylate to obtain a butyl acrylate solution. Add 1.2 parts of cumene hydroperoxide to 50 parts of water and mix thoroughly to obtain an initiator solution. Add 150 parts of the above seed emulsion to reactor 2, control the reaction temperature at 65℃, and add the above butyl acrylate solution and initiator solution dropwise using a constant flow pump. The butyl acrylate solution is added over 3 hours, and the initiator solution is added over 3.5 hours, resulting in a rubber emulsion with a mantle layer. The particle size was measured to be 183 nm.

[0082] Grafting stage: Grafting monomer and emulsion preparation: Add 46 parts styrene, 25 parts acrylonitrile, 5 parts methyl methacrylate, 0.8 parts sodium dodecylbenzenesulfonate, and 0.4 parts sodium formaldehyde sulfoxylate to 80 parts deionized water, stir for 30 minutes until the emulsion is stable, and obtain the pre-emulsion.

[0083] 0.16 parts of ferrous sulfate (catalyst) and 0.32 parts of disodium ethylenediaminetetraacetate (chelating agent) were added to 200 parts of rubber latex containing the mantle layer. Stirring was started for 15 minutes until the latex became homogeneous and did not separate into layers. Nitrogen gas was introduced while the temperature was raised to 55°C. The pre-emulsion was then added dropwise to the reactor over 4 hours. 1.5 parts of cumene hydroperoxide solution (initiator) was added over 5 hours to obtain an ASA latex with a measured particle size of 230 nm. The mass ratio of the rubber core, mantle layer, and shell layer was determined to be 1:1.05:0.6.

[0084] Flocculation stage: Prepare a 10% magnesium sulfate aqueous solution, and slowly add ASA emulsion to it while stirring. Then filter and dry at 85°C to obtain ASA powder.

[0085] Comparative Example 5 The difference from Example 1 is that methyl methacrylate is not added during the grafting stage. The specific operation is as follows: Rubber nucleus synthesis stage: 200 parts deionized water, 40 parts butyl acrylate, 20 parts methyl methacrylate, 1.8 parts allyl methacrylate (crosslinking agent), 1.5 parts potassium oleate (emulsifier), 2 parts sodium dodecyl sulfate (emulsifier), 0.2 parts tert-dodecyl mercaptan (chain transfer agent), 0.4 parts sodium formaldehyde sulfoxylate (reducing agent), 0.1 parts ferrous sulfate (co-catalyst), and 0.2 parts disodium ethylenediaminetetraacetate (chelating agent) were added to the polymerization reactor using a high-pressure pump. Stirring was started for pre-emulsification. The reactor was then purged three times with nitrogen to remove oxygen. 1.2 parts of cumene hydroperoxide solution were then added to the reactor. The temperature was initially raised to 73°C, and the reaction was continued for 5 hours to obtain rubber seed latex with a measured particle size of 75 nm.

[0086] Rubber mantle synthesis stage: Add 1.2 parts of sodium dodecyl sulfate (emulsifier) ​​to 90 parts of butyl acrylate to obtain a butyl acrylate solution. Add 1.2 parts of cumene hydroperoxide to 50 parts of water and mix thoroughly to obtain an initiator solution. Add 150 parts of the above seed emulsion to reactor 2, control the reaction temperature at 65℃, and add the above butyl acrylate solution and initiator solution dropwise using a constant flow pump. The butyl acrylate solution is added over 3 hours, and the initiator solution is added over 3.5 hours, resulting in a rubber emulsion with a mantle layer. The particle size was measured to be 180 nm.

[0087] Grafting stage: Grafting monomer and emulsion preparation: Add 46 parts styrene, 25 parts acrylonitrile, 0.8 parts sodium dodecylbenzenesulfonate, and 0.4 parts sodium formaldehyde sulfoxylate (reducing agent) to 80 parts deionized water, and stir for 30 minutes until the emulsion is stable to obtain a pre-emulsion.

[0088] 0.16 parts of ferrous sulfate (catalyst) and 0.32 parts of disodium ethylenediaminetetraacetate (chelating agent) were added to 200 parts of rubber latex containing the mantle layer. Stirring was started for 15 minutes until the latex was homogeneous and did not separate into layers. Nitrogen gas was introduced while the temperature was raised to 55°C. The pre-emulsion was then added dropwise to the reactor over 4 hours. 1.5 parts of cumene hydroperoxide solution (initiator) was added over 5 hours to obtain an ASA latex with a measured particle size of 223 nm. The mass ratio of the rubber core, mantle layer, and shell layer was determined to be 1:0.9:0.39.

[0089] Flocculation stage: Prepare a 10% magnesium sulfate aqueous solution, and slowly add ASA emulsion to it while stirring. Then filter and dry at 85°C to obtain ASA powder.

[0090] Performance testing The synthesized ASA powder and SAN resin obtained in each example and comparative example were mixed evenly with 1.5% (percentage of total mass) at a mass ratio of 3:7. The resulting mixture was extruded in an extruder at 220°C to obtain extruded rubber strips. The extruded rubber strips were tested according to the method in Table 1, and the specific test results are shown in Table 2.

[0091] Table 1

[0092] Table 2

[0093] The above test results show that, compared with the comparative example, the materials prepared by Examples 1 to 10 using the technical solution of the present invention have better impact performance. Compared with the comparative example, the materials obtained by the examples have a lower L value and better dyeing performance. The present invention prepares latex with different particle sizes to obtain products with different particle size distributions. The final products maintain good dyeing effect while having high impact strength, which is better than the comparative example.

[0094] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A multilayer ASA material, characterized in that, It includes a rubber core, mantle, and shell; The rubber core is a copolymer elastomer formed by copolymerization and crosslinking of butyl acrylate and hard segment monomers; The mantle layer, which wraps around the outer surface of the rubber core, is polymerized from acrylate monomers. The shell layer, which wraps around the outer surface of the mantle layer, is composed of styrene, methyl methacrylate, and acrylonitrile graft copolymer. The hard segment monomer is one or two of hydroxyethyl acrylate, glycidyl methacrylate, methyl methacrylate, ethyl methacrylate, styrene and methylstyrene. The particle size of the rubber core is 30-150 nm; the particle size of the mantle layer is 80-200 nm; and the particle size of the shell layer is 150-300 nm. The mass ratio of the rubber core, mantle, and shell is 1-4:2-8:1-5; The crosslinking agent used for crosslinking is 1-5% of the weight of the reactant monomer; the crosslinking agent is divinylbenzene, ethylene glycol diglycidyl ether, dicyclopentadiene acrylate, allyl methacrylate, hexamethoxymethyl melamine resin, dimethacrylate or diallyl compound.

2. The multilayer ASA material according to claim 1, characterized in that, The rubber core is synthesized with a butyl acrylate to hard segment monomer raw material weight ratio of 1.5-5:

1.

3. The multilayer ASA material according to claim 1, characterized in that, The mass ratio of styrene, acrylonitrile, and methyl methacrylate is 50-70:15-40:5-15.

4. A method for preparing the multilayer ASA material according to any one of claims 1-3, characterized in that, Includes the following steps: 1) The butyl acrylate, hard segment monomer, crosslinking agent, emulsifier, chain transfer agent, reducing agent, catalyst and chelating agent are mixed and then pre-emulsified to obtain a pre-emulsion; 2) After adjusting the temperature of the pre-emulsion obtained above to 45-75℃, mix it with the initiator to react, so that the monomer conversion rate reaches more than 90%, and obtain the rubber core emulsion. 3) Adjust the temperature of the rubber core emulsion obtained above to 65-86℃, and add acrylate monomers and initiator solutions dropwise to react. The monomer conversion rate reaches more than 98%, and a rubber emulsion with a mantle layer is obtained. 4) Mix the rubber latex, catalyst and chelating agent of the above-mentioned mantle layer, adjust the temperature to 35-75℃, add the pre-emulsion and initiator dropwise to react and obtain ASA latex; The pre-emulsion is obtained by mixing deionized water, styrene, methyl methacrylate, acrylonitrile, reducing agent and emulsifier; The emulsifier is one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, sodium dodecyl sulfate, potassium oleate, potassium stearate, and potassium disproportionated rosinate; the amount of emulsifier added is 4-15% of the relative mass of the polymerizing monomer.

5. The preparation method according to claim 4, characterized in that, In step 3), the initiator is added for a longer time than the acrylate monomer, and for more than 20 minutes.

6. The preparation method according to claim 4, characterized in that, In step 4), the initiator is added for a longer time than the pre-emulsion, and for more than 40 minutes.

7. The preparation method according to claim 4, characterized in that, The reaction time in step 2) is 5-12 hours.

8. The preparation method according to claim 4, characterized in that, The reaction time in step 3) is 1-6 hours.

9. The preparation method according to claim 4, characterized in that, The reaction time in step 4) is 2-8 hours.

10. The preparation method according to claim 4, characterized in that, After obtaining ASA latex in step 4), the process also includes slowly adding the ASA latex to a flocculant aqueous solution while stirring, filtering, and drying to obtain ASA powder.

Images