Nano coated PVC modifier

Abstract

The invention belongs to the technical field of high polymer material modification, and particularly relates to a nano coated PVC modifier which is a core-shell structure composite particle, and the core-shell structure composite particle comprises a core layer, a transition layer and a shell layer which are sequentially arranged from inside to outside; the core layer is an ABS rubber phase, the transition layer is an acrylonitrile-styrene copolymer grafted and modified by maleic anhydride, and the shell layer is of a gradient composite structure; the shell layer comprises an inner layer and an outer layer which are sequentially arranged from inside to outside, through the structural design of a flexible core, a modified transition layer and a rigid gradient shell, an ABS rubber phase serves as an energy absorption center, the impact toughness of PVC is improved through cavitation and crazing shearing mechanisms, the CaTP nano shell layer refines PVC crystals through the heterogeneous nucleation effect, rigid support is provided, and the impact toughness of PVC is improved. The problem of rigidity reduction caused by traditional ABS toughening is solved.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification technology, specifically to a nano-coated PVC modifier. Background Technology

[0002] Thermoplastic polymer products, especially semi-rigid and rigid PVC products, require the addition of processing aids or solubilizing small-molecule organic compounds to their formulations to meet processing requirements. Among these, acrylate additives can increase viscosity and lower temperature, while small-molecule organic compounds such as oils, waxes, and plasticizers can achieve a solubilizing effect. Although the addition of these additives can improve processing fluidity, their molecular structure characteristics significantly reduce the rigidity and heat resistance of PVC products, severely limiting their application scenarios.

[0003] Existing technologies suffer from numerous industry pain points due to limitations in additives. For example, in the field of building formwork, PVC materials lack sufficient rigidity after the addition of traditional processing additives, failing to meet the structural support strength requirements of building construction. Existing domestic materials struggle to overcome this performance bottleneck, leading to the continued widespread use of metal formwork in the construction industry. This not only results in excessive consumption of metal resources but also contradicts the national green development strategy of "replacing steel with plastics." Similarly, in the plastic flooring industry, the processing aids used in traditional PVC flooring formulations lead to insufficient heat resistance in the products. These products are prone to deformation and warping in high-temperature environments during summer or near heat sources (such as radiators and lamps), affecting user experience and lifespan. Furthermore, outdoor PVC products (such as outdoor flooring and railings) lack UV resistance, making them prone to aging, discoloration, and cracking after long-term exposure, further limiting the application range of PVC materials. To improve the impact toughness of PVC products, the industry often uses direct blending of ABS and PVC for modification. However, this method has obvious drawbacks: although the addition of ABS can improve impact strength, it will lead to a significant decrease in the flexural modulus (rigidity) of PVC products, creating a technical contradiction of "increasing toughness inevitably reduces rigidity". At the same time, the melt flow of the direct blending system is poor, the plasticizing time during processing is long and the energy consumption is high, and the thermal stability of PVC is not effectively improved. The core-shell structure is prone to "shell separation" phenomenon, and the performance degrades significantly after long-term use, which limits the application of modified PVC products in high-performance structural scenarios. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A nano-coated PVC modifier, wherein the modifier is a core-shell structured composite particle, the core-shell structured composite particle comprising a core layer, a transition layer and a shell layer arranged sequentially from the inside out; the core layer is an ABS rubber phase (acrylonitrile-butadiene-styrene terpolymer), the transition layer is a maleic anhydride (MAH) graft-modified acrylonitrile-styrene copolymer (SAN), and the shell layer is a gradient composite structure; the shell layer comprises an inner layer and an outer layer arranged sequentially from the inside out, the inner layer is a nanosheet structured calcium terephthalate (CaTP), and the outer layer is glycidyl methacrylate (GMA) modified nano-calcium terephthalate.

[0005] As a preferred embodiment of the nano-coated PVC modifier described in this invention, the shell layer contains 3%-8% (based on the mass of calcium terephthalate) nano-zinc oxide (ZnO)@titanium oxide ( Core-shell particles, preferably rutile titanium dioxide.

[0006] As a preferred embodiment of the nano-coated PVC modifier of the present invention, the inner layer thickness is set to 5-15 nm, and the outer layer thickness is set to 5-15 nm.

[0007] As a preferred embodiment of the nano-coated PVC modifier described in this invention, the nano zinc oxide@titanium oxide particles have a nano zinc oxide core particle size of 2-5 nm and a titanium oxide shell thickness of 1-2 nm.

[0008] As a preferred embodiment of the nano-coated PVC modifier described in this invention, it further includes a preparation method, the specific steps of which are as follows: S1, Preparation of maleic anhydride-grafted ABS polymer: ABS graft polymer is prepared according to conventional emulsion polymerization process. When the polymerization reaction reaches 80%, maleic anhydride monomer accounting for 3%-5% of the mass of acrylonitrile-styrene copolymer is added, the reaction continues, and the particle size of polybutadiene rubber particles is controlled to finally obtain maleic anhydride-grafted ABS polymer with carboxyl groups retained at the end of acrylonitrile-styrene copolymer chain segments and containing anhydride groups. S2, Preparation of composite calcium terephthalate dispersion: S21, terephthalic acid and calcium salt are mixed in stoichiometric ratio and dispersed in an aqueous solution by stirring to form a uniform calcium terephthalate precursor dispersion. S22, add 5%-10% glycidyl methacrylate monomer and 0.5%-1% azobisisobutyronitrile (initiator) to the dispersion to carry out pre-reaction and form glycidyl methacrylate modified calcium terephthalate dispersion. S23, add nano zinc oxide@titanium oxide core-shell particles to glycidyl methacrylate modified calcium terephthalate dispersion in proportion, and perform ultrasonic dispersion to obtain composite calcium terephthalate dispersion. S3, Staged Ultrasonic-Microwave Coordinated In-situ Coating Reaction: In the later stage of ABS graft polymerization, a composite calcium terephthalate dispersion is added to the reaction system for staged treatment. In the first stage (0-15 minutes), ultrasonic treatment is applied to achieve uniform spreading of the dispersion on the surface of ABS particles. In the second stage (15-30 minutes), ultrasonic treatment is turned off, and microwave irradiation is activated, utilizing the carboxyl groups at the ends of the acrylonitrile-styrene copolymer segments to... A coordination reaction occurs, and at the same time, the anhydride group of maleic anhydride forms a cross-linking effect with the epoxy group of glycidyl methacrylate, so that the composite calcium terephthalate is coated on the surface of ABS particles in a gradient structure. S4, Post-processing: After the reaction is completed, the product is demulsified, washed, and dried to obtain a nano-coated PVC multifunctional modifier.

[0009] As a preferred embodiment of the nano-coated PVC modifier of the present invention, wherein: the reaction time in S1 is set to 1-1.5 hours, and the particle size of the polybutadiene rubber particles is controlled at 0.1-0.5 μm.

[0010] In a preferred embodiment of the nano-coated PVC modifier described in this invention, in step S21, the pH value of the aqueous solution is set to 6.5-7.5.

[0011] In a preferred embodiment of the nano-coated PVC modifier described in this invention, in step S22, the pre-reaction temperature is set to 40-50℃ and the pre-reaction time is set to 30-35 minutes.

[0012] In a preferred embodiment of the nano-coated PVC modifier described in this invention, the ultrasonic dispersion time in step S23 is set to 20-25 minutes.

[0013] As a preferred embodiment of the nano-coated PVC modifier described in this invention, in step S3, the ultrasonic power of the first stage is set to 300-500W, and the microwave irradiation frequency of the second stage is set to 2450MHz, with a power of 100-150W.

[0014] Compared with existing technologies: 1. Through the structural design of "flexible core-modified transition layer-rigid gradient shell", the ABS rubber phase serves as the energy absorption center, and the impact toughness of PVC is improved through voiding and crazing shear mechanism. The CaTP nanoshell refines PVC crystals and provides rigid support through heterogeneous nucleation effect, which solves the problem of rigidity reduction caused by traditional ABS toughening. 2. By coordinating the carboxyl groups of the CaTP shell with the unstable chlorine atoms of PVC, the degradation sites of the material are reduced. At the same time, the cross-linking effect between the MAH grafted transition layer and the shell inhibits the thermal motion of the molecular chain, thereby simultaneously improving the heat resistance and thermal stability of PVC products and solving the problem of insufficient heat resistance caused by traditional processing aids. 3. The core-shell gradient structure and MAH grafting modification reduce the viscosity of PVC melt and improve processing rheological properties. At the same time, the staged ultrasonic-microwave synergistic process improves the uniformity of particle dispersion, thereby improving plasticizing efficiency, reducing energy consumption, and improving melt flowability during processing, and solving the problem of poor processability of direct blending systems. 4. Enhanced interfacial bonding: Through the transesterification reaction between the anhydride groups of the transition layer MAH and the PVC molecular chain, the coordination with the shell layer CaTP, and the ring-opening reaction between the epoxy groups of the outer layer GMA and the unstable chlorine atoms of PVC, multiple chemical bonds of "core-transition layer-shell-PVC matrix" are formed, which significantly improves the interfacial bonding and solves the problem of easy "shell detachment" of traditional core-shell structures. 5. Through the ZnO@ in the shell The ultraviolet absorption of composite particles The shell layer prevents ZnO from undergoing a catalytic degradation reaction with PVC, thereby improving the outdoor weather resistance of PVC products and solving the problem of easy aging of traditional PVC products after long-term outdoor use. 6. Expanding Application Scenarios: Through comprehensive optimization of rigidity, toughness, heat resistance, processability, interface stability, and UV resistance, the application scenarios of PVC products are further expanded. They can not only meet the stringent requirements of structural strength for building formwork and heat deformation resistance for plastic flooring, but also adapt to the weather resistance requirements of outdoor building materials, thus aligning with the development strategies of relevant industries. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below. Example 1:

[0016] This invention provides a nano-coated PVC modifier, wherein the modifier is a core-shell structured composite particle, comprising a core layer, a transition layer, and a shell layer arranged sequentially from the inside out; the core layer is an ABS rubber phase (acrylonitrile-butadiene-styrene terpolymer), the transition layer is a maleic anhydride (MAH) graft-modified acrylonitrile-styrene copolymer (SAN), and the shell layer is a gradient composite structure; the shell layer comprises an inner layer and an outer layer arranged sequentially from the inside out, the inner layer is a nanosheet structured calcium terephthalate (CaTP), and the outer layer is glycidyl methacrylate (GMA) modified nano-calcium terephthalate.

[0017] The shell contains 3% (based on the mass of calcium terephthalate) nano-zinc oxide (ZnO)@titanium oxide. The nano zinc oxide@titanium oxide particles have a core particle size of 2 nm and a titanium oxide shell thickness of 1 nm, and are rutile titanium oxide.

[0018] The thickness of the inner layer is set to 5 nm, and the thickness of the outer layer is set to 5 nm.

[0019] It also includes a preparation method, the specific steps of which are as follows: S1, Preparation of maleic anhydride-grafted ABS polymer: ABS graft polymer was prepared according to conventional emulsion polymerization process. When the polymerization reaction reached 80%, maleic anhydride monomer accounting for 3% of the mass of the acrylonitrile-styrene copolymer was added, and the reaction continued. The particle size of the polybutadiene rubber particles was controlled to finally obtain a maleic anhydride-grafted ABS polymer in which the acrylonitrile-styrene copolymer chain segments retained carboxyl groups at the end and contained anhydride groups. The reaction time was set to 1 hour, and the particle size of the polybutadiene rubber particles was controlled at 0.1 μm. S2, Preparation of composite calcium terephthalate dispersion: S21, terephthalic acid and calcium salt are mixed in stoichiometric ratio and dispersed in an aqueous solution by stirring to form a uniform calcium terephthalate precursor dispersion; wherein, the pH value of the aqueous solution is set to 6.5. S22, add 5% glycidyl methacrylate monomer and 0.5% azobisisobutyronitrile (initiator) of calcium terephthalate to the dispersion to carry out a pre-reaction to form a glycidyl methacrylate modified calcium terephthalate dispersion; wherein, the pre-reaction temperature is set to 40℃ and the pre-reaction time is set to 30 minutes. S23, nano zinc oxide@titanium oxide core-shell particles are added to glycidyl methacrylate modified calcium terephthalate dispersion in a certain proportion and ultrasonically dispersed to obtain composite calcium terephthalate dispersion; wherein, the ultrasonic dispersion time is set to 20 minutes. S3, Staged Ultrasonic-Microwave Coordinated In-situ Coating Reaction: In the later stage of ABS graft polymerization, a composite calcium terephthalate dispersion is added to the reaction system for staged treatment. In the first stage (0 minutes), ultrasonic treatment is applied to achieve uniform spreading of the dispersion on the surface of ABS particles. In the second stage (15 minutes), ultrasonic treatment is turned off, and microwave irradiation is turned on, utilizing the carboxyl groups at the ends of the acrylonitrile-styrene copolymer segments to... A coordination reaction occurs, and at the same time, the anhydride group of maleic anhydride forms a cross-linking effect with the epoxy group of glycidyl methacrylate, so that the composite calcium terephthalate is coated on the surface of ABS particles in a gradient structure; wherein, the ultrasonic power of the first stage is set to 300W, and the microwave irradiation frequency of the second stage is set to 2450MHz and the power is set to 100W. S4, Post-processing: After the reaction is completed, the product is demulsified, washed, and dried to obtain a nano-coated PVC multifunctional modifier. Example 2:

[0020] This invention provides a nano-coated PVC modifier, wherein the modifier is a core-shell structured composite particle, comprising a core layer, a transition layer, and a shell layer arranged sequentially from the inside out; the core layer is an ABS rubber phase (acrylonitrile-butadiene-styrene terpolymer), the transition layer is a maleic anhydride (MAH) graft-modified acrylonitrile-styrene copolymer (SAN), and the shell layer is a gradient composite structure; the shell layer comprises an inner layer and an outer layer arranged sequentially from the inside out, the inner layer is a nanosheet structured calcium terephthalate (CaTP), and the outer layer is glycidyl methacrylate (GMA) modified nano-calcium terephthalate.

[0021] The shell contains 5.5% (based on the mass of calcium terephthalate) nano-zinc oxide (ZnO)@titanium oxide. The nano zinc oxide@titanium oxide particles have a core particle size of 3.5 nm and a titanium oxide shell thickness of 1.5 nm, and are rutile titanium oxide.

[0022] The thickness of the inner layer is set to 10 nm, and the thickness of the outer layer is set to 10 nm.

[0023] It also includes a preparation method, the specific steps of which are as follows: S1, Preparation of maleic anhydride-grafted ABS polymer: ABS graft polymer was prepared according to conventional emulsion polymerization process. When the polymerization reaction reached 80%, maleic anhydride monomer accounting for 4% of the mass of the acrylonitrile-styrene copolymer was added, and the reaction continued. The particle size of the polybutadiene rubber particles was controlled to finally obtain a maleic anhydride-grafted ABS polymer in which the acrylonitrile-styrene copolymer chain segments retained carboxyl groups at the ends and contained anhydride groups. The reaction time was set to 1.25 hours, and the particle size of the polybutadiene rubber particles was controlled at 0.35 μm. S2, Preparation of composite calcium terephthalate dispersion: S21, terephthalic acid and calcium salt are mixed in stoichiometric ratio and dispersed in an aqueous solution by stirring to form a uniform calcium terephthalate precursor dispersion; wherein, the pH value of the aqueous solution is set to 7.0. S22, add 7.5% glycidyl methacrylate monomer and 0.75% azobisisobutyronitrile (initiator) by mass of calcium terephthalate to the dispersion to carry out a pre-reaction to form a glycidyl methacrylate modified calcium terephthalate dispersion; wherein, the pre-reaction temperature is set to 45℃ and the pre-reaction time is set to 32.5 minutes. S23, nano zinc oxide@titanium oxide core-shell particles were added to a glycidyl methacrylate modified calcium terephthalate dispersion in a certain proportion and ultrasonically dispersed to obtain a composite calcium terephthalate dispersion; wherein, the ultrasonic dispersion time was set to 22.5 minutes. S3, Staged Ultrasonic-Microwave Coordinated In-situ Coating Reaction: In the later stage of ABS graft polymerization, a composite calcium terephthalate dispersion is added to the reaction system for staged treatment. In the first stage (7.5 minutes), ultrasonic treatment is applied to achieve uniform spreading of the dispersion on the surface of ABS particles. In the second stage (22.5 minutes), ultrasonic treatment is turned off, and microwave irradiation is activated, utilizing the carboxyl groups at the ends of the acrylonitrile-styrene copolymer segments to... A coordination reaction occurs, and at the same time, the anhydride group of maleic anhydride forms a cross-linking effect with the epoxy group of glycidyl methacrylate, so that the composite calcium terephthalate is coated on the surface of ABS particles in a gradient structure; wherein, the ultrasonic power of the first stage is set to 400W, and the microwave irradiation frequency of the second stage is set to 2450MHz and the power is set to 125W. S4, Post-processing: After the reaction is completed, the product is demulsified, washed, and dried to obtain a nano-coated PVC multifunctional modifier. Example 3:

[0024] This invention provides a nano-coated PVC modifier, wherein the modifier is a core-shell structured composite particle, comprising a core layer, a transition layer, and a shell layer arranged sequentially from the inside out; the core layer is an ABS rubber phase (acrylonitrile-butadiene-styrene terpolymer), the transition layer is a maleic anhydride (MAH) graft-modified acrylonitrile-styrene copolymer (SAN), and the shell layer is a gradient composite structure; the shell layer comprises an inner layer and an outer layer arranged sequentially from the inside out, the inner layer is a nanosheet structured calcium terephthalate (CaTP), and the outer layer is glycidyl methacrylate (GMA) modified nano-calcium terephthalate.

[0025] The shell contains 8% (based on the mass of calcium terephthalate) nano-zinc oxide (ZnO)@titanium oxide. The nano zinc oxide@titanium oxide particles have a core particle size of 5 nm and a titanium oxide shell thickness of 2 nm, and are rutile titanium oxide.

[0026] The thickness of the inner layer is set to 15nm, and the thickness of the outer layer is set to 15nm.

[0027] It also includes a preparation method, the specific steps of which are as follows: S1, Preparation of maleic anhydride-grafted ABS polymer: ABS graft polymer was prepared according to conventional emulsion polymerization process. When the polymerization reaction reached 80%, maleic anhydride monomer accounting for 5% of the mass of the acrylonitrile-styrene copolymer was added, and the reaction continued. The particle size of the polybutadiene rubber particles was controlled to finally obtain a maleic anhydride-grafted ABS polymer in which the acrylonitrile-styrene copolymer chain segments retained carboxyl groups at the ends and contained anhydride groups. The reaction time was set to 1.5 hours, and the particle size of the polybutadiene rubber particles was controlled at 0.5 μm. S2, Preparation of composite calcium terephthalate dispersion: S21, terephthalic acid and calcium salt are mixed in stoichiometric ratio and dispersed in an aqueous solution by stirring to form a uniform calcium terephthalate precursor dispersion; wherein, the pH value of the aqueous solution is set to 7.5. S22, add 10% glycidyl methacrylate monomer and 1% azobisisobutyronitrile (initiator) of calcium terephthalate to the dispersion to carry out a pre-reaction to form a glycidyl methacrylate modified calcium terephthalate dispersion; wherein, the pre-reaction temperature is set to 50℃ and the pre-reaction time is set to 35 minutes. S23, nano zinc oxide@titanium oxide core-shell particles are added to glycidyl methacrylate modified calcium terephthalate dispersion in a certain proportion and ultrasonically dispersed to obtain composite calcium terephthalate dispersion; wherein, the ultrasonic dispersion time is set to 25 minutes. S3, Staged Ultrasonic-Microwave Coordinated In-situ Coating Reaction: In the later stage of ABS graft polymerization, a composite calcium terephthalate dispersion is added to the reaction system for staged treatment. In the first stage (15 minutes), ultrasonic treatment is applied to achieve uniform spreading of the dispersion on the surface of ABS particles. In the second stage (30 minutes), ultrasonic treatment is turned off and microwave irradiation is turned on, utilizing the carboxyl groups at the ends of the acrylonitrile-styrene copolymer segments to... A coordination reaction occurs, and at the same time, the anhydride group of maleic anhydride forms a cross-linking effect with the epoxy group of glycidyl methacrylate, so that the composite calcium terephthalate is coated on the surface of ABS particles in a gradient structure; wherein, the ultrasonic power of the first stage is set to 500W, and the microwave irradiation frequency of the second stage is set to 2450MHz and the power is set to 150W. S4, Post-processing: After the reaction is completed, the product is demulsified, washed, and dried to obtain a nano-coated PVC multifunctional modifier.

[0028] The modifier prepared in the examples was applied to the formulation of PVC outdoor pipe fittings, and the specific formulation is shown in Table 1 below: Table 1: Experimental formulations

[0029] The product was manufactured according to the above formula, and its performance was tested. The following data were obtained, as detailed in Table 2: Table 2: Physical Property Data Table

[0030] As shown in the table above, compared to the traditional method of using ABS, the modifier of this invention, when applied to PVC formulations, exhibits significant advantages in toughening, stiffness, and heat resistance, while demonstrating good processing rheological properties and reducing processing energy consumption. Even with reduced amounts of UV absorbers and light stabilizers in the compared formulations, the modifier of this invention also ensures the product's weather resistance, and even significantly improves its resistance to light aging. Comparing the use of the modifiers in Examples 1-3, Example 2 shows the best results.

[0031] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A nano-coated PVC modifier, characterized by, The modifier is a core-shell structure composite particle, which comprises a core layer, a transition layer and a shell layer arranged in sequence from inside to outside; the core layer is an ABS rubber phase, the transition layer is a maleic anhydride grafted modified acrylonitrile-styrene copolymer, and the shell layer is a gradient composite structure; the shell layer comprises an inner layer and an outer layer arranged in sequence from inside to outside, the inner layer is a calcium terephthalate with a nano sheet layer structure, and the outer layer is a glycidyl methacrylate modified nano calcium terephthalate.

2. The nano-coated PVC modifier according to claim 1, characterized in that, 3%-8% of nano zinc oxide@titanium oxide core-shell particles are compounded in the shell layer.

3. The nano-coated PVC modifier according to claim 1, characterized in that, The thickness of the inner layer is 5-15 nm, and the thickness of the outer layer is 5-15 nm.

4. The nano-coated PVC modifier according to claim 2, characterized in that, The nano zinc oxide core particle size in the nano zinc oxide@titanium oxide particle is 2-5 nm, and the titanium oxide shell thickness is 1-2 nm.

5. The nano-coated PVC modifier according to claim 1, characterized in that, Also comprising a preparation method, the specific steps are as follows: S1, preparing a maleic anhydride grafted ABS graft polymer: preparing an ABS graft polymer according to an emulsion polymerization process, when the polymerization reaction is carried out to 80%, adding 3%-5% of maleic anhydride monomers based on the mass of the acrylonitrile-styrene copolymer, continuing to react, and controlling the polybutadiene rubber particle size, finally obtaining a maleic anhydride grafted ABS graft polymer with carboxyl groups remaining at the end of the acrylonitrile-styrene copolymer segment and containing anhydride groups; S2, preparing a composite calcium terephthalate dispersion liquid: S21, mixing terephthalic acid and calcium salt according to the stoichiometric ratio, stirring and dispersing in an aqueous solution to form a uniform calcium terephthalate precursor dispersion liquid; S22, adding 5%-10% of glycidyl methacrylate monomers and 0.5%-1% of azobisisobutyronitrile based on the mass of the calcium terephthalate to the dispersion liquid, pre-reacting to form a glycidyl methacrylate modified calcium terephthalate dispersion liquid; S23, adding nano zinc oxide@titanium oxide core-shell particles in proportion to the glycidyl methacrylate modified calcium terephthalate dispersion liquid, ultrasonic dispersing to obtain a composite calcium terephthalate dispersion liquid; S3, staged ultrasonic-microwave synergistic in-situ coating reaction: during the later stage of ABS graft polymerization, the composite calcium terephthalate dispersion liquid is added to the reaction system, and is treated in stages. In the first stage, ultrasonic treatment is applied to achieve uniform spreading of the dispersion liquid on the surface of the ABS particles. In the second stage, the ultrasonic treatment is turned off, and microwave irradiation is turned on. The carboxyl groups at the end of the acrylonitrile-styrene copolymer chain segment are used to coordinate with the calcium ions in the composite calcium terephthalate dispersion liquid, and cross-linking is formed between the acid anhydride groups of the maleic anhydride and the epoxy groups of the glycidyl methacrylate, so that the composite calcium terephthalate is coated on the surface of the ABS particles in a gradient structure. The coordination reaction occurs, and cross-linking is formed between the acid anhydride groups of the maleic anhydride and the epoxy groups of the glycidyl methacrylate, so that the composite calcium terephthalate is coated on the surface of the ABS particles in a gradient structure. S4, post-treatment: after the reaction is completed, demulsifying, washing and drying to obtain a nano-coated PVC multifunctional modifier.

6. The nano-coated PVC modifier according to claim 5, characterized in that, The reaction time in S1 is 1-1.5 hours, and the polybutadiene rubber particle size is controlled to be 0.1-0.5 μm.

7. The nano-coated PVC modifier according to claim 5, characterized in that, In S21, the pH value of the aqueous solution is 6.5-7.

5.

8. The nano-coated PVC modifier according to claim 5, characterized in that, In S22, the pre-reaction temperature is 40-50°C, and the pre-reaction time is 30-35 minutes.

9. The nano-coated PVC modifier according to claim 5, characterized in that, In S23, the ultrasonic dispersion time is 20-25 minutes.

10. The nano-coated PVC modifier according to claim 5, characterized in that, In S3, the ultrasonic power in the first stage is 300-500 W, the microwave irradiation frequency in the second stage is 2450 MHz, and the power is 100-150 W.

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