Magnetic polyvinyl chloride microsphere, preparation method and application of magnetic polyvinyl chloride microsphere in polyvinyl chloride resin polymerization

Abstract

The invention discloses a magnetic polyvinyl chloride microsphere, a preparation method and an application of the magnetic polyvinyl chloride microsphere in polyvinyl chloride resin polymerization, the magnetic polyvinyl chloride microsphere with a core-shell structure is prepared, the shell layer is polyvinyl chloride containing an ion catching agent, the core layer is polyvinyl chloride containing magnetic particles, and the core layer is magnetic particles. Wherein the shell layer ion trapping agent can efficiently trap foreign ions, the magnetic particles of the core layer have magnetism, and the magnetic polyvinyl chloride microspheres can be separated and removed through magnetic field adsorption; the magnetic polyvinyl chloride microsphere is applied to polymerization of polyvinyl chloride resin, impurity ions in the polyvinyl chloride polymerization process are efficiently captured by using an ion capturing agent in the magnetic polyvinyl chloride microsphere, and the magnetic polyvinyl chloride microsphere is removed by using a magnetic field, so that the insulativity and whiteness of the polyvinyl chloride resin and the insulativity of a processed product of the polyvinyl chloride resin are improved.

Description

Technical Field

[0001] The invention relates to the technical field of polyvinyl chloride preparation, and more specifically to a magnetic polyvinyl chloride microsphere, a preparation method and application thereof in polyvinyl chloride resin polymerization. Background Art

[0002] Polyvinyl chloride resin is a plastic with excellent mechanical properties and chemical corrosion resistance, and is widely used in the fields of wire insulation materials, electronic equipment casings, etc. However, since impurity ions such as chloride ions, sodium ions, and iron ions are easily introduced during the production process of polyvinyl chloride resin, the product performance is poor, such as low insulation and low thermal stability of the product, and low electrical insulation of subsequent polyvinyl chloride resin products. Therefore, it is necessary to improve the quality of polyvinyl chloride resin products by removing impurity ions in the production process of polyvinyl chloride resin.

[0003] By adding an ion capture agent, impurity ions in the polymerization process of polyvinyl chloride resin can be adsorbed and removed. For example, the invention patent with publication number CN118085471A discloses a method for preparing polyvinyl chloride resin granules. By adding an ion capture agent during the granulation process of polyvinyl chloride resin, wherein the ion capture agent is at least one of an anion capture agent, a cation capture agent, and a zwitterion capture agent, and its content is 0.01-6wt% of the weight of the polyvinyl chloride resin, the impurity ions in the polyvinyl chloride resin product can be efficiently captured, and the impurity ions are fixed in the polyvinyl chloride resin composite material by utilizing the steric effect of the ion capture agent, so that it is not easy to form a conductive path in the PVC composite material, thereby improving the insulation of the polyvinyl chloride composite material; although this method can improve the insulation of the material to a certain extent, the impurity ions and the ion capture agent still remain in the polyvinyl chloride resin product, which easily leads to insufficient stability of the material.

[0004] Therefore, if the impurity ions in the polyvinyl chloride resin are to be completely removed without retaining the additives added for removing the impurity ions, a new method for producing the polyvinyl chloride resin needs to be developed.

[0005] Magnetic polymer microspheres are formed by combining organic polymers and inorganic magnetic particles by appropriate chemical methods to form microspheres with certain magnetism and special structures. By performing different modifications on the surface of magnetic polymer microspheres, different functions can be given to the magnetic polymer microspheres. For example, the invention patent with publication number CN104120256A provides a method for separating rare earth ions using magnetic polymer microspheres, which uses a monomer polymerization method to prepare polymer microspheres with superparamagnetism, and modifies the surface of the microspheres with functional groups that can form a chelate structure with rare earth ions, and achieves adsorption of rare earth ions through the functional groups, but this method has not been applied to the polymerization of polyvinyl chloride resins. Summary of the invention

[0006] In view of the above, the present invention provides a magnetic polyvinyl chloride microsphere, a preparation method and an application thereof in polyvinyl chloride resin polymerization, which can remove the capture agent that has captured the impurity ions in the polyvinyl chloride resin product.

[0007] The invention provides a magnetic polyvinyl chloride microsphere, which has a core-shell structure and comprises an outer shell layer and a core layer from the outside to the inside, wherein the outer shell layer is polyvinyl chloride containing an ion capture agent, and the core layer is polyvinyl chloride containing magnetic particles.

[0008] The ion capture agent contained in the magnetic polyvinyl chloride microspheres can capture impurity ions in the polymerization of polyvinyl chloride resin, such as sodium ions, calcium ions, copper ions, iron ions, chloride ions, sulfate ions, etc., and form a stable complex. The magnetic particles contained in the magnetic polyvinyl chloride microspheres are paramagnetic, and the magnetic polyvinyl chloride microspheres adsorbed with ionic impurities can be removed through a strong magnetic field, thereby improving the product performance of the polyvinyl chloride resin.

[0009] The thickness of the outer shell layer is 1 to 20 μm, and the diameter of the core layer is 30 to 150 μm; when the thickness of the outer shell layer is less than 1 μm, the ion capture effect is poor; when the thickness of the outer shell layer is greater than 20 μm, the magnetic properties of the magnetic polyvinyl chloride microspheres are weak, and the separation effect is poor; when the diameter of the core layer is less than 30 μm, the magnetic properties of the magnetic polyvinyl chloride microspheres are weak, and the separation effect is poor; when the diameter of the core layer is greater than 150 μm, the overall particle size of the magnetic polyvinyl chloride microspheres is large, the specific surface area is large, and the ion capture efficiency is low. At the same time, the magnetic polyvinyl chloride microspheres are heavy, which reduces their magnetic removal rate; the incompatibility between the thickness of the outer shell layer and the diameter of the core layer is not conducive to the product performance of the polyvinyl chloride resin.

[0010] The ion capture agent is one or both of an anion capture agent and a cation capture agent, the anion capture agent is one or both of hydrotalcite or bismuth oxide hydrate, and the cation capture agent is one or more of zirconium polyphosphate, zirconium phosphate, zirconium antimonate, zirconium molybdate, zirconium selenate, zirconium tungstate, zirconium tellurate, zirconium silicate, and zirconium phosphosilicate.

[0011] The particle size of the ion capture agent is 0.1 to 10 μm. When the particle size of the ion capture agent is less than 0.1 μm, the ion capture effect is poor. When the particle size of the ion capture agent is greater than 10 μm, it will not be stable in the outer shell layer, and will fall off and cannot be separated from the polyvinyl chloride resin, affecting the product performance of the polyvinyl chloride resin.

[0012] The magnetic particles include iron, ferroferric oxide, nickel, and iron-nickel alloy, and their particle sizes are 0.1 to 20 μm; the magnetic particles have a particle size of less than 0.1 μm, which is difficult to disperse and will cause the overall magnetism of the magnetic polyvinyl chloride microspheres to be weak, resulting in magnetic attraction failure; the magnetic particles have a particle size of greater than 20 μm, which cannot be stabilized in the core layer, and will also cause the magnetism of the magnetic polyvinyl chloride microspheres to be weak, resulting in magnetic attraction failure, which will have an adverse effect on the product performance of the polyvinyl chloride resin.

[0013] In addition, the present invention also provides a method for preparing magnetic polyvinyl chloride microspheres, comprising the following steps: (1) adding vinyl chloride monomer, deionized water, dispersant, initiator, and magnetic particles into a polymerization kettle, stirring and heating, and performing a polymerization reaction. When the average particle size of the polymer reaches the required value, adding a terminator to stop the reaction, collecting the magnetic particle-polyvinyl chloride mixture, washing it with deionized water, and then drying and sieving to obtain P1 particles; (2) Add vinyl chloride monomer, deionized water, dispersant, initiator, P1 particles, and ion capture agent into a polymerization kettle, stir and heat, and carry out polymerization reaction. When the polymer particle size reaches the requirement, add a terminator to stop the reaction, wash with deionized water, and then dry and sieve to obtain magnetic polyvinyl chloride microspheres.

[0014] The amount of magnetic particles used is 25 to 300 wt% of the mass of the vinyl chloride monomer added in step (1); when the content of magnetic particles is lower than 25 wt%, the adsorption force of the external magnetic field on the magnetic microspheres is relatively small, which may easily cause the magnetic microspheres to mix into the product, which is not conducive to the product performance of the polyvinyl chloride resin; when the content of magnetic particles is higher than 300 wt%, the strength of the magnetic microspheres is reduced, and they may be easily broken during the stirring process, resulting in the diffusion of magnetic particles and contamination of the product, which is also not conducive to the product performance of the polyvinyl chloride resin.

[0015] The amount of the ion capture agent used is 0.1 to 20 wt% of the mass of the vinyl chloride monomer added in step (2); when the ion capture agent content is lower than 0.1%, the adsorption effect on the impurity ions is poor; when the ion capture agent content is higher than 20 wt%, the adsorption effect on the impurity ions is no longer enhanced, but the cost will increase. At the same time, the mechanical strength of the magnetic polyvinyl chloride microspheres will be weakened, resulting in easy breakage during the polymerization and stirring process of the polyvinyl chloride resin, causing the ion capture agent to fail, which is not conducive to the product performance of the polyvinyl chloride resin.

[0016] The present invention also uses magnetic polyvinyl chloride microspheres in the polymerization of polyvinyl chloride resin, and the polyvinyl chloride resin is prepared by the following method: Add vinyl chloride monomer, deionized water, dispersant, initiator, magnetic polyvinyl chloride microspheres into a polymerization kettle, stir and heat, and carry out polymerization reaction. After the reaction conversion rate reaches 80%, add a terminator, and then the material is stripped, dried, and sieved through a sieve, and the magnetic polyvinyl chloride microspheres are adsorbed by a magnet to finally obtain polyvinyl chloride resin.

[0017] The amount of magnetic polyvinyl chloride microspheres used is 0.01-0.5wt% of the mass of vinyl chloride monomer added in the polymerization of polyvinyl chloride resin; when the amount of magnetic polyvinyl chloride microspheres used is lower than 0.01wt%, the ion capture effect is not obvious; when the amount of magnetic polyvinyl chloride microspheres used is higher than 0.5wt%, the ion capture effect does not increase, but instead causes some magnetic microspheres to remain, which is not conducive to the product performance of polyvinyl chloride resin.

[0018] The invention prepares magnetic polyvinyl chloride microspheres with a core-shell structure, wherein the outer shell layer is polyvinyl chloride containing an ion capture agent, and the core layer is polyvinyl chloride containing magnetic particles, wherein the ion capture agent in the outer shell layer can efficiently capture impurity ions, and the magnetic particles in the core layer have magnetism, and the magnetic polyvinyl chloride microspheres can be separated and removed by adsorption using a magnetic field; the magnetic polyvinyl chloride microspheres are applied to the polymerization of polyvinyl chloride resin, wherein the ion capture agent in the magnetic polyvinyl chloride microspheres is used to efficiently capture impurity ions in the polymerization process of the polyvinyl chloride resin, and the magnetic polyvinyl chloride microspheres are removed by using a magnetic field, thereby achieving simultaneous removal of impurity ions and ion capture agents in the polymerization of the polyvinyl chloride resin, thereby improving the product performance of the polyvinyl chloride resin, and improving the insulation and whiteness of the polyvinyl chloride resin and the insulation of processed products thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural diagram of the magnetic polyvinyl chloride microspheres of the present invention.

[0020] Markings in the figure are: 1-shell layer polyvinyl chloride, 2-ion capture agent, 3-core layer polyvinyl chloride, 4-magnetic particles. DETAILED DESCRIPTION

[0021] The embodiments of the present application will be described in more detail below. The application can be implemented in various forms, and should not be construed as being limited to the embodiments set forth herein, but rather these embodiments are provided to provide a more thorough and complete understanding of the present application. It should be understood that the embodiments of the present application are only for exemplary purposes and are not intended to limit the scope of protection of the present application.

[0022] The structure diagram of the magnetic polyvinyl chloride microspheres of the present invention is shown in the attached figure. Figure 1 As shown, the embodiments and comparative examples are implemented according to the following technical solutions: 1. Preparation of magnetic polyvinyl chloride microspheres, the specific steps include: (1) Preparation of P1 particles: 100 parts of vinyl chloride monomer, 80 parts of deionized water, 0.5 parts of dispersant, 0.01 parts of initiator, and 25 to 300 parts of magnetic particles are added to a polymerization kettle, stirred and heated to 56° C. to carry out polymerization reaction. After the average particle size of the polymer reaches the required value, a terminator is added to stop the reaction, and the magnetic particle-polyvinyl chloride mixture is collected, washed with deionized water, dried, and sieved to obtain P1 particles; wherein the magnetic particles include iron, ferroferric oxide, nickel, and iron-nickel alloy, and the particle size thereof is 0.1 to 20 μm; (2) Preparation of magnetic polyvinyl chloride microspheres: 50 parts of vinyl chloride monomer, 40 parts of deionized water, 0.25 parts of dispersant, 0.005 parts of initiator, 30 parts of P1 particles, and 0.05-10 parts of ion scavengers were added into a polymerization kettle, wherein the mass ratio of anion scavengers to cation scavengers in the ion scavengers was 1:1, and the mixture was stirred and heated to 56°C to carry out polymerization reaction. After the polymer particle size reached the required value, a terminator was added to stop the reaction, and magnetic polyvinyl chloride microspheres were obtained after washing, filtering, drying, and sieving. The particle size of the ion scavenger was 0.1-10 μm, the outer shell layer thickness of the magnetic polyvinyl chloride microspheres was 1-20 μm, and the core layer diameter was 40-100 μm.

[0023] 2. Polymerization of polyvinyl chloride resin, the specific steps include: Add 100 parts of vinyl chloride monomer, 100 parts of deionized water, 0.5 parts of dispersant, 0.01 parts of initiator, and 0.01-0.5 parts of magnetic polyvinyl chloride microspheres based on the mass of the vinyl chloride monomer added in this step into a polymerization kettle, stir and heat to 56° C. to carry out polymerization reaction, add a terminator after the reaction conversion rate reaches 80%, and after the material is stripped and dried, sieved through a 250 μm sieve, and the magnetic polyvinyl chloride microspheres are adsorbed by a strong neodymium magnet to finally obtain polyvinyl chloride resin.

[0024] The embodiments and comparative examples were conducted under the same magnetic field strength, which was 4000 Gauss.

[0025] Table 1 shows the specific implementation conditions of the embodiments of the present invention and the comparative examples, and Table 2 shows the properties of the polyvinyl chloride obtained by the embodiments of the present invention and the comparative examples, wherein the properties and test methods of the polyvinyl chloride resin are as follows: Conductivity of water extract: The test method refers to GB / T 2915 Determination of conductivity of water extract of polyvinyl chloride resin. The lower the conductivity of water extract, the better the insulation of polyvinyl chloride resin. Whiteness: GB / T 15595-2008 Whiteness method for thermal stability test of polyvinyl chloride resin.

[0026] Volume resistivity of processed products: After mixing polyvinyl chloride resin, inorganic filler, plasticizer, stabilizer, etc., granulation is performed, and then further processed into a composite sheet material. The volume resistivity of the sheet material is tested. The higher the volume resistivity, the better the insulation properties of the processed polyvinyl chloride resin product.

[0027] From the test results in Table 2, it can be obtained that the insulation and whiteness of the polyvinyl chloride resins prepared in Examples 1 to 5 and the insulation of their processed products are significantly improved compared with the insulation and whiteness of the polyvinyl chloride resins prepared in Comparative Example 1 without using magnetic polyvinyl chloride microspheres and the insulation of their processed products. This shows that the magnetic polyvinyl chloride microspheres prepared in the present invention can effectively adsorb impurity ions in the polymerization process of polyvinyl chloride resin, and finally separate the magnetic polyvinyl chloride microspheres from the polyvinyl chloride resin, thereby effectively removing impurity ions in the polymerization of polyvinyl chloride resin without residual ion capture agent, thereby improving the product performance of polyvinyl chloride resin, and improving the insulation and whiteness of polyvinyl chloride resin and the insulation of its processed products.

[0028] At the same time, the overall performance of the polyvinyl chloride resin and its processed products prepared in Examples 1 to 5 and Comparative Examples 2 to 15 is better than the overall performance of the polyvinyl chloride resin and its processed products prepared in Comparative Example 1 without using magnetic polyvinyl chloride microspheres, indicating that the use of magnetic polyvinyl chloride microspheres can remove impurity ions in the polymerization of polyvinyl chloride resin and ion capture agents used to adsorb impurity ions, thereby improving the product performance of polyvinyl chloride resin.

[0029] Among them, Comparative Examples 2 and Comparative Examples 3 are cases in which the core layer diameter of the magnetic polyvinyl chloride microspheres is too small and too large, respectively, and the insulation properties of the processed polyvinyl chloride resin products obtained are poor, which proves that the inappropriate core layer diameter of the magnetic polyvinyl chloride microspheres will reduce the insulation properties of the processed polyvinyl chloride resin products; the core layer diameter is too small, resulting in weak magnetism, poor separation effect of the magnetic polyvinyl chloride microspheres and polyvinyl chloride resin, and reduced insulation properties of the processed polyvinyl chloride resin products; the core layer diameter is too large, the overall particle size of the magnetic polyvinyl chloride microspheres is large, the specific surface area is large, resulting in low ion capture efficiency, and the magnetic polyvinyl chloride microspheres are heavy, which reduces the magnetic adsorption removal rate, so that the insulation properties of the processed polyvinyl chloride resin products are reduced.

[0030] Among them, Comparative Examples 4 and 5 are cases in which the dosage of magnetic particles is too low and too high, respectively. The insulation properties of the processed polyvinyl chloride resin products obtained are both poor, which proves that inappropriate dosage of magnetic particles will have an adverse effect on the insulation properties of the processed polyvinyl chloride resin products; if the dosage of magnetic particles is too low, the magnetic attraction part will fail, and the magnetic polyvinyl chloride microspheres in the polyvinyl chloride resin cannot be completely removed, which reduces the insulation properties of the processed polyvinyl chloride resin products; if the dosage of magnetic particles is too high, the coating effect of polyvinyl chloride is weak, and during the polymerization process of polyvinyl chloride resin, the magnetic polyvinyl chloride microspheres are easily broken under high-speed stirring, so that the magnetic particles are scattered in the product, polluting the product, resulting in reduced insulation properties of the processed polyvinyl chloride resin products.

[0031] Among them, Comparative Examples 6 and Comparative Examples 7 are cases in which the particle size of the magnetic particles is too small and too large, respectively. The insulation properties of the prepared polyvinyl chloride resin and its processed products are poor, which proves that the inappropriate particle size of the magnetic particles will reduce the insulation properties of the processed products of the polyvinyl chloride resin; the magnetic particles are too small and difficult to disperse, and the overall magnetism of the magnetic polyvinyl chloride microspheres will be weak, resulting in failure of magnetic attraction; the magnetic particles are too large and cannot be stabilized in the core layer, which will also cause the magnetism of the magnetic polyvinyl chloride microspheres to be weak, resulting in failure of magnetic attraction; therefore, the magnetic particles with too small or too large particle sizes cannot completely remove the magnetic polyvinyl chloride microspheres in the polyvinyl chloride resin, which reduces the insulation properties of the processed products of the polyvinyl chloride resin.

[0032] Among them, Comparative Example 8 is a case in which the thickness of the outer shell layer of the magnetic polyvinyl chloride microspheres is too small, and the insulation and whiteness of the obtained polyvinyl chloride resin and the insulation of its processed products are all poor, which proves that the outer shell layer of the magnetic polyvinyl chloride microspheres is too thin, the ion capture effect is poor, and the impurity ions in the polymerization of the polyvinyl chloride resin cannot be effectively removed, resulting in the reduction of the insulation and whiteness of the polyvinyl chloride resin and the insulation of its processed products; Comparative Example 9 is a case in which the thickness of the outer shell layer of the magnetic polyvinyl chloride microspheres is too large, and the insulation of the processed products of the polyvinyl chloride resin is poor, which proves that the excessive thickness of the outer shell layer of the magnetic polyvinyl chloride microspheres will weaken the magnetism of the microspheres, resulting in poor separation effect of the magnetic polyvinyl chloride microspheres, and reduced insulation of the processed products of the polyvinyl chloride resin.

[0033] Among them, Comparative Example 10 is a case in which the dosage of the ion capture agent is too low. The insulation and whiteness of the polyvinyl chloride resin obtained and the insulation of its processed products are poor, which proves that the dosage of the ion capture agent is too low, the ion capture effect is poor, and the impurity ions in the polymerization of the polyvinyl chloride resin cannot be effectively removed, resulting in the reduction of the insulation and whiteness of the polyvinyl chloride resin and the insulation of its processed products; Comparative Example 11 is a case in which the dosage of the ion capture agent is too high. The insulation of the processed products of the polyvinyl chloride resin is poor, which proves that the dosage of the ion capture agent is too high, and the ion capture effect has reached its limit, which leads to weak mechanical strength of the magnetic polyvinyl chloride microspheres, which are easy to break during the polymerization stirring process of the polyvinyl chloride resin, causing the ion capture agent to fail, and reducing the insulation of the processed products of the polyvinyl chloride resin.

[0034] Among them, Comparative Example 12 is a case in which the particle size of the ion capture agent is too small. The insulation and whiteness of the prepared polyvinyl chloride resin and the insulation of its processed products are all poor, which proves that the particle size of the ion capture agent is too small. After being coated with the polyvinyl chloride resin, the ion capture effect is poor, and the impurity ions in the polymerization of the polyvinyl chloride resin cannot be effectively removed, resulting in the insulation and whiteness of the polyvinyl chloride resin and the insulation of its processed products are all reduced; Comparative Example 13 is a case in which the particle size of the ion capture agent is too large. The insulation of the processed product of the polyvinyl chloride resin is poor, which proves that the particle size of the ion capture agent is too large, which will cause it to be unable to be stabilized in the outer shell layer and thus fall off. Then, in the subsequent preparation process of polyvinyl chloride, it will remain in the polyvinyl chloride product and cannot be separated, which reduces the insulation of the processed product of the polyvinyl chloride resin.

[0035] Among them, Comparative Example 14 is a case in which the amount of magnetic polyvinyl chloride microspheres is too small. The insulation and whiteness of the prepared polyvinyl chloride resin and the insulation of its processed products are poor, which proves that the amount of magnetic polyvinyl chloride microspheres is too small, the ion capture effect is not obvious, resulting in reduced insulation and whiteness of the polyvinyl chloride resin and the insulation of its processed products; Comparative Example 15 is a case in which the amount of magnetic polyvinyl chloride microspheres is too large. Although the insulation of the prepared polyvinyl chloride resin and its processed products is relatively good, the effect is not increased. On the contrary, some magnetic polyvinyl chloride microspheres remain, which not only increases the cost, but is also not conducive to the insulation of the processed products of the polyvinyl chloride resin; It proves that appropriate magnetic polyvinyl chloride microspheres are more beneficial to the performance of polyvinyl chloride resin and its processed products.

[0036] Table 1: Specific implementation conditions of the embodiments of the present invention and comparative examples.

[0037] Table 2: Properties of polyvinyl chloride resins prepared in the examples of the present invention and comparative examples.

[0038] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in this application, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A magnetic polyvinyl chloride microsphere, characterized in that: The magnetic polyvinyl chloride microsphere has a core-shell structure, and comprises an outer shell layer and a core layer from the outside to the inside, wherein the outer shell layer is polyvinyl chloride containing an ion capture agent, and the core layer is polyvinyl chloride containing magnetic particles.

2. The magnetic polyvinyl chloride microsphere according to claim 1, characterized in that: The thickness of the outer shell layer is 1 to 20 μm.

3. The magnetic polyvinyl chloride microsphere according to claim 1, characterized in that: The core layer has a diameter of 30 to 150 μm.

4. The magnetic polyvinyl chloride microsphere according to claim 1, characterized in that: The particle size of the ion capture agent is 0.1 to 10 μm.

5. The magnetic polyvinyl chloride microsphere according to claim 1, characterized in that: The ion capture agent is one or both of an anion capture agent and a cation capture agent.

6. The magnetic polyvinyl chloride microsphere according to claim 5, characterized in that: The anion scavenger is one or both of hydrotalcite and bismuth oxide hydrate; the cation scavenger is one or more of zirconium polyphosphate, zirconium phosphate, zirconium antimonate, zirconium molybdate, zirconium selenate, zirconium tungstate, zirconium tellurate, zirconium silicate, and zirconium phosphosilicate.

7. The magnetic polyvinyl chloride microsphere according to claim 1, characterized in that: The particle size of the magnetic particles is 0.1-20 μm.

8. The magnetic polyvinyl chloride microsphere according to claim 1, characterized in that: The magnetic particles include iron, ferroferric oxide, nickel, and iron-nickel alloy.

9. The method for preparing magnetic polyvinyl chloride microspheres according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) adding vinyl chloride monomer, deionized water, dispersant, initiator, and magnetic particles into a polymerization kettle, stirring and heating, and performing a polymerization reaction. When the average particle size of the polymer reaches the required value, adding a terminator to stop the reaction, collecting the magnetic particle-polyvinyl chloride mixture, washing it with deionized water, and then drying and sieving to obtain P1 particles; (2) Add vinyl chloride monomer, deionized water, dispersant, initiator, P1 particles, and ion capture agent into a polymerization kettle, stir and heat, and carry out polymerization reaction. When the polymer particle size reaches the requirement, add a terminator to stop the reaction, wash with deionized water, and then dry and sieve to obtain magnetic polyvinyl chloride microspheres.

10. The method for preparing magnetic polyvinyl chloride microspheres according to claim 9, characterized in that: The amount of the magnetic particles used is 25 to 300 wt % of the mass of the vinyl chloride monomer added in step (1).

11. The method for preparing magnetic polyvinyl chloride microspheres according to claim 9, characterized in that: The amount of the ion capture agent used is 0.1 to 20 wt % of the mass of the vinyl chloride monomer added in step (2).

12. The use of magnetic polyvinyl chloride microspheres according to any one of claims 1 to 8, characterized in that: The magnetic polyvinyl chloride microspheres are used in the polymerization of polyvinyl chloride resin.

13. The use of magnetic polyvinyl chloride microspheres according to claim 12, characterized in that: The polymerization of polyvinyl chloride resin is carried out by the following method: Add vinyl chloride monomer, deionized water, dispersant, initiator, magnetic polyvinyl chloride microspheres into a polymerization kettle, stir and heat, and carry out polymerization reaction. After the reaction conversion rate reaches 80%, add a terminator, and then the material is stripped, dried, and sieved through a sieve, and the magnetic polyvinyl chloride microspheres are adsorbed by a magnet to finally obtain polyvinyl chloride resin.

14. The use of magnetic polyvinyl chloride microspheres according to claim 13, characterized in that: The amount of the magnetic polyvinyl chloride microspheres used is 0.01-0.5 wt % of the mass of the vinyl chloride monomer added in the polymerization of the polyvinyl chloride resin.

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