A polymer microsphere containing a surfactant unit

Abstract

The application discloses a polymer microsphere containing a surfactant unit. The polymer microsphere is prepared by a suspension polymerization method, and the polymer microsphere comprises the following units: A, an oil phase unit; B, a reactive surfactant unit; and C, an initiator unit. The application replaces a conventional surfactant with a reactive surfactant, and the amount of the reactive surfactant is smaller than that of a non-reactive surfactant. In addition, a suitable type of the reactive surfactant makes the microsphere dispersion more stable in the polymerization process, so that the polymer microsphere has a more concentrated particle size distribution, a smooth surface and excellent heat resistance. Meanwhile, the polymer microsphere disclosed by the application does not contain silica or residual suspending agent, and does not affect the application field of the polymer microsphere, so that the polymer microsphere has a greater application prospect in technical fields such as electronics, optoelectronics, optics, medicine and building.

Description

Technical Field

[0001] This invention belongs to the field of polymer microsphere preparation, specifically relating to a polymer microsphere containing surfactant units. Background Technology

[0002] Polymer microspheres originated in 1955 when Vanderhoff and Brandford at Hay College in the United States prepared polystyrene microspheres with highly uniform particle size, and have been extensively developed over the following decades. Polymer microsphere materials possess unique size, morphology, and functions, and polymer / inorganic composite microspheres obtained by adding inorganic materials combine the performance advantages of both organic and inorganic materials. Therefore, polymer microspheres and polymer-inorganic composite microsphere materials have enormous application prospects in the fields of electronics, optoelectronics, optics, medicine, and architecture.

[0003] Currently, various polymerization methods have been developed to prepare polymeric microspheres or polymer / inorganic composite microspheres with uniform size. Among them, emulsion polymerization has been studied extensively. However, emulsion polymerization often requires the addition of a large amount of surfactants and dispersants during the preparation process. The polymerization method has problems such as complicated operation, long time consumption, easy environmental pollution, wide particle size distribution, poor sphericity, and high cost.

[0004] To address these issues, suspension polymerization can be used for improvement. For example, patent CN102597012B utilizes silica as a dispersant in conjunction with an emulsifier for suspension polymerization to prepare polymer microspheres with silica on their surface. However, the silica on the surface of the microspheres is difficult to remove, limiting its application in some areas. Patent CN101054427B discloses a method for preparing monodisperse micron-sized polymethyl methacrylate by controlling the heating rate in the initial stage of the dispersion polymerization of methyl methacrylate. However, the suspending agent in this method is difficult to remove from the system after the reaction, affecting its application. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a polymer microsphere containing surfactant units. The polymer microsphere has a more concentrated particle size distribution, a smooth surface, excellent heat resistance, and its applications are unrestricted.

[0006] Another object of the present invention is to provide a method for preparing the polymer microspheres.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A polymer microsphere containing surfactant units, said polymer microsphere being prepared by suspension polymerization, said polymer microsphere comprising the following units by weight percentage:

[0009] A: Oil phase unit

[0010] B: Reactive surfactant unit,

[0011] C: Initiator unit,

[0012] The oil phase unit comprises residues formed by the reaction of polymeric monomers and crosslinking monomers; the mass ratio of polymeric monomers to crosslinking monomers is 50–99.5:0.5–50.

[0013] The reactive surfactant unit is formed from the residues of the reactive surfactant after reaction. The reactive surfactant is one or more of allyloxynonylphenol polyoxyethylene ether sulfate, allyloxy aromatic alcohol polyoxyethylene ether sulfonate, allyloxy fatty alcohol polyoxyethylene ether sulfonate, alkyl olefin polyoxyethylene ether phosphate, and polyethylene glycol monomethyl ether methacrylate. The mass of the reactive surfactant unit is 0.1% to 10% of the mass of the oil phase unit.

[0014] The initiator unit is formed from the residues after the initiator reaction.

[0015] In this invention, the reactive surfactant contains groups capable of chemically reacting with polymer monomers and crosslinking monomers, thus incorporating them into the structure of the polymer microspheres. However, the inventors discovered that not all surfactants capable of reacting with polymer monomers and crosslinking monomers can result in a more concentrated particle size distribution, a smooth surface, and excellent heat resistance in the polymer microspheres. Through extensive experimentation, the inventors found that when the reactive surfactant is allyloxynonylphenol polyoxyethylene ether sulfate, allyloxy aromatic alcohol polyoxyethylene ether sulfonate, allyloxy fatty alcohol polyoxyethylene ether sulfonate, alkyl olefin polyoxyethylene ether phosphate, or polyethylene glycol monomethyl ether methacrylate, its reaction with the polymer monomers and crosslinking monomers results in a more concentrated particle size distribution, a smooth surface, and excellent heat resistance in the polymer microspheres.

[0016] In this invention, the allyloxynonylphenol polyoxyethylene ether sulfate commonly includes sodium allyloxynonylphenol polyoxyethylene ether (40) sulfate, ammonium allyloxynonylphenol polyoxyethylene ether (30) sulfate, ammonium allyloxynonylphenol polyoxyethylene ether (10) sulfate, ammonium allyloxynonylphenol polyoxyethylene ether (20) sulfate, etc.

[0017] In this invention, the allyloxy aromatic alcohol polyoxyethylene ether sulfonate commonly includes ammonium allyloxy aromatic alcohol polyoxyethylene ether sulfonate.

[0018] In this invention, the allyloxy fatty alcohol polyoxyethylene ether sulfonate commonly includes ammonium / potassium allyloxy fatty alcohol polyoxyethylene ether sulfonate, ammonium allyloxy fatty alcohol polyoxyethylene ether sulfonate, etc.

[0019] In this invention, the alkyl olefin polyoxyethylene ether phosphate commonly includes alkyl olefin polyoxyethylene ether phosphate, etc.

[0020] In this invention, the polyethylene glycol monomethyl ether methacrylate commonly includes polyethylene glycol (1000) monomethyl ether methacrylate, polyethylene glycol (2000) monomethyl ether methacrylate, etc.

[0021] The above are merely examples; the degree of polymerization in the surfactant described in this invention can also be selected from other values.

[0022] Preferably, the polymerizing monomer is one or more of styrene, α-methylstyrene, ethyl acrylate, butyl acrylate, isobutyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, glycidyl methacrylate, acrylic acid, itaconic acid, dibutyl maleate, dioctyl maleate, acrylamide, methacrylamide, acrylonitrile, ethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, dimethylaminoethyl methacrylate, or 2-hydroxypropyl methacrylate.

[0023] Preferably, the mass ratio of the polymeric monomer to the crosslinking monomer is 60-99:1-40.

[0024] Preferably, the mass of the reactive surfactant unit is 0.2% to 5% of the mass of the oil phase unit;

[0025] Preferably, the crosslinking monomer is one or more of ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, propoxylated triglyceride triacrylate, and dipentaerythritol pentaacrylate.

[0026] Preferably, the initiator unit is a residue formed by an azo initiator or a peroxide initiator.

[0027] More specifically, the azo initiator may be one or more of the following azo compounds: 2,2-azobisisobutyronitrile, 2,2-azobis-2-methylbutyronitrile, 2,2-azobis-2,4-dimethylpentanitrile, 2,2-azobis-4-methoxy-2,4-dimethylpentanitrile, 2,2-azobis(2-methylpropionate), and 2,2-azobis(2-methylpropanediamine)·2-hydrochloride.

[0028] The peroxide initiator may be one or more of the following: cumene hydroperoxide (CHP), di-tert-butyl peroxide, dicumyl peroxide, benzoyl peroxide (BPO), lauroyl peroxide (LPO), dimethyl bis(tert-butyl peroxide)hexane, dimethyl bis(tert-butyl peroxide)-3-hexyne, bis(tert-butyl peroxide isopropyl)benzene, bis(tert-butyl peroxide)trimethylcyclohexane, butyl-bis(tert-butyl peroxide)valerate, tert-butyl peroxy-2-ethylhexanoate, benzoyl peroxide, terpene hydrogen peroxide, and tert-butyl peroxide.

[0029] The method for preparing the polymer microspheres includes the following steps:

[0030] S1. Preparation of oil phase solution: Mix the polymerizing monomer, crosslinking monomer, and initiator to prepare an oil phase solution;

[0031] S2. Preparation of aqueous solution: Deionized water and reactive surfactant are mixed to prepare aqueous solution; the amount of reactive surfactant is 0.1-10% of the total mass of polymeric monomer and crosslinking monomer;

[0032] S3. Mix and emulsify the oil phase solution and aqueous phase solution obtained in S1. and S2., add them to the reaction vessel, stir the reaction under nitrogen gas, and after the reaction is completed, ripen and cool to obtain the crude product;

[0033] S4. Separate the crude product described in S3., dry the solid, and pulverize it to obtain polymer microspheres.

[0034] If necessary, a reducing agent may be added to the oil phase solution. Preferably, the reducing agent is a naphthenate (cobalt salt, manganese salt, vanadium salt, iron salt, etc.) or a tertiary amine compound (such as N,N-dimethylaniline, N,N-diethylaniline) and a thiol, etc.

[0035] In S1, the mass ratio of the polymeric monomer to the crosslinking monomer is 50-99.5:0.5-50.

[0036] Preferably, the mass ratio of polymeric monomer to crosslinking monomer in S1 is 60-99:1-40.

[0037] Preferably, in S1, the amount of initiator is equivalent to 0.1-2% of the total mass of the polymerizing monomer and the crosslinking monomer.

[0038] Increasing the initiator dosage leads to a change in the average droplet size of the emulsion, which initially decreases and then increases. The droplet size ultimately determines the size of the polymer microspheres formed. As the initiator dosage increases, the rate of primary free radical generation accelerates, the number of active centers increases, and the average particle size of the resulting polymer microspheres decreases under a fixed total monomer content. However, excessive initiator dosage accelerates the termination of the reaction, shortens the average lifetime of free radicals entering the latex particles, reduces initiator efficiency during polymer microsphere synthesis, slows down the reaction rate, and reduces the number of latex particles actually participating in the reaction, resulting in an increase in the polymer microsphere particle size.

[0039] More preferably, in S1, the amount of initiator is equivalent to 0.3 to 1% of the total mass of the polymerizing monomer and the crosslinking monomer.

[0040] Preferably, in S2, the amount of reactive surfactant is 0.2 to 5% of the total mass of the polymerizing monomer and the crosslinking monomer.

[0041] The amount of reactive surfactant has a significant impact on the formation of polymer microsphere emulsions and the size of emulsion droplets, with the droplet size determining the particle size of the polymer microspheres. When the amount of reactive surfactant is too small, some of the oil phase solution will not be emulsified and will remain free in the emulsion, where it will polymerize during the reaction to form polymer microsphere byproducts. However, when the amount of reactive surfactant is too large, the emulsion system becomes viscous, affecting the emulsification effect and hindering the uniform dispersion of emulsion droplets.

[0042] In this invention, the ratio range of deionized water to oil phase commonly used in existing suspension polymerization methods can be referenced. Preferably, in S2, the mass ratio of deionized water to the total mass of polymerizing monomers to crosslinking monomers is 1.5 to 15:1.

[0043] More preferably, in S2, the amount of deionized water and the mass ratio of the total mass of the polymerizing monomer to the crosslinking monomer are 2 to 10:1.

[0044] In this invention, the temperature range commonly used in existing suspension polymerization methods can be referenced. Preferably, in step S3, the reaction temperature is 20–70°C.

[0045] In this invention, the emulsification time range commonly used in existing suspension polymerization methods can be referenced. Preferably, in step S3, the mixing and emulsification time is 10–120 min.

[0046] Preferably, in step S3, the ripening is carried out at 75–90°C.

[0047] Preferably, in S4, the separation method is filtration.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] This invention provides a novel polymer microsphere prepared by suspension polymerization, using a reactive surfactant instead of a conventional surfactant. The reactive surfactant allows for a lower dosage compared to non-reactive surfactants, and the appropriate type of reactive surfactant ensures more stable microsphere dispersion during polymerization, resulting in a more concentrated particle size distribution, smooth surface, and excellent heat resistance. Furthermore, the polymer microspheres of this invention are free of silica or residual suspending agents, thus preserving their application scope and demonstrating greater potential in fields such as electronics, optoelectronics, optics, medicine, and construction. Attached Figure Description

[0050] Figure 1 Scanning electron microscope image of the polymer microspheres prepared in Example 4;

[0051] Figure 2 Electron microscope image of the polymer microspheres prepared in Example 4. Detailed Implementation

[0052] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are only used to explain the present invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0053] In the examples, the polyethylene glycol (2000) monomethyl ether methacrylate, allyloxy fatty alcohol polyoxyethylene ether (20) ammonium sulfonate, allyloxy nonylphenol polyoxyethylene ether (40) sodium sulfate, alkyl olefin polyoxyethylene ether phosphate, allyloxy nonylphenol polyoxyethylene ether (30) ammonium sulfate, allyloxy aromatic alcohol polyoxyethylene ether (40) ammonium sulfonate, allyloxy fatty alcohol polyoxyethylene ether (30) ammonium sulfonate, polyethylene glycol (1000) monomethyl ether methacrylate, allyloxy nonylphenol polyoxyethylene ether (10) ammonium sulfate, and sodium dodecyl sulfonate used were all commercially available products.

[0054] Example 1

[0055] S1. Weigh 69 parts by weight of styrene, 1 part by weight of α-methylstyrene, 30 parts by weight of ethylene glycol dimethacrylate and 1 part by weight of 2-2 azobisisobutyronitrile and add them to reactor A. Stir and disperse until completely dissolved to obtain an oil phase solution.

[0056] S2. Weigh 500 parts by weight of deionized water, 0.1 parts by weight of polyethylene glycol (2000) monomethyl ether methacrylate and 0.1 parts by weight of allyloxy fatty alcohol polyoxyethylene ether (20) ammonium sulfonate and add them to reactor B. Stir and disperse until completely dissolved to obtain an aqueous solution.

[0057] S3. Add all the oil phase solution and aqueous phase solution obtained in S1 and S2 into the emulsification tank, emulsify for 30 minutes, then transfer to the reaction vessel, stir with nitrogen, heat to 55℃ and react for 10 hours, heat to 85℃ and mature for 2 hours, then cool to 50℃ to obtain the crude product.

[0058] S4. Filter and separate the crude product described in S3, dry and pulverize the filtered solid to obtain polymer microspheres 1.

[0059] Example 2

[0060] S1. Weigh 80 parts by weight of styrene, 2 parts by weight of pentaerythritol tetraacrylate and 0.3 parts by weight of benzoyl peroxide and add them to reactor A. Stir and disperse until completely dissolved to obtain an oil phase solution.

[0061] S2. Weigh 300 parts by weight of deionized water, 2 parts by weight of sodium allyloxynonylphenol polyoxyethylene ether (40) sulfate and 0.2 parts by weight of alkyl olefin polyoxyethylene ether phosphate and add them to reactor B. Stir and disperse until completely dissolved to obtain an aqueous solution.

[0062] S3. Add all the oil phase solution and aqueous phase solution obtained in S1 and S2 into the emulsification tank, emulsify for 30 minutes, then transfer to the reaction vessel, stir with nitrogen, heat to 65℃ for 6 hours, heat to 85℃ for 2 hours, and then cool to 50℃ to obtain the crude product.

[0063] S4. Filter and separate the crude product described in S3, dry and pulverize the filtered solid to obtain polymer microspheres 2.

[0064] Example 3

[0065] S1. Weigh 90 parts by weight of styrene, 10 parts by weight of pentaerythritol tetraacrylate, 0.3 parts by weight of benzoyl peroxide, and 0.1 parts by weight of N,N-dimethylaniline and add them to reactor A. Stir and disperse until completely dissolved to obtain an oil phase solution.

[0066] S2. Weigh 400 parts by weight of deionized water and 3 parts by weight of allyloxynonylphenol polyoxyethylene ether (30) ammonium sulfate and add them to reactor B. Stir and disperse until completely dissolved to obtain an aqueous solution.

[0067] S3. Add all the oil phase solution and aqueous phase solution obtained in S1 and S2 into the emulsification tank, emulsify for 10 minutes, then transfer to the reaction vessel, stir with nitrogen, heat to 35℃ and react for 12 hours, heat to 85℃ and mature for 2 hours, then cool to 50℃ to obtain the crude product.

[0068] S4. Filter and separate the crude product described in S3, dry and pulverize the filtered solid to obtain polymer microspheres 3.

[0069] Example 4

[0070] S1. Weigh 70 parts by weight of methyl methacrylate, 30 parts by weight of ethylene glycol dimethacrylate and 0.7 parts by weight of 2,2-azobisisobutyronitrile and add them to reactor A. Stir and disperse until completely dissolved to obtain an oil phase solution.

[0071] S2. Weigh 200 parts by weight of deionized water and 0.5 parts by weight of allyloxy aromatic alcohol polyoxyethylene ether (40) ammonium sulfonate and add them to reactor B. Stir and disperse until completely dissolved to obtain an aqueous phase solution.

[0072] S3. Add all the oil phase solution and aqueous phase solution obtained in S1 and S2 into the emulsification tank, emulsify for 10 minutes, then transfer to the reaction vessel, stir with nitrogen, heat to 60℃ for 6 hours, heat to 85℃ for 2 hours, and then cool to 50℃ to obtain the crude product.

[0073] S4. Filter and separate the crude product described in S3, dry and pulverize the filtered solid to obtain polymer microspheres 4.

[0074] Example 5

[0075] S1. Weigh 90 parts by weight of methyl methacrylate, 5 parts by weight of butyl methacrylate, 5 parts by weight of pentaerythritol triacrylate and 0.5 parts by weight of peroxylauroyl (LPO) and add them to reactor A. Stir and disperse until completely dissolved to obtain an oil phase solution.

[0076] S2. Weigh 400 parts by weight of deionized water, 1 part by weight of potassium ammonium sulfonate of allyloxy fatty alcohol polyoxyethylene ether (30) and 0.1 part by weight of polyethylene glycol (1000) monomethyl ether methacrylate and add them to reactor B. Stir and disperse until completely dissolved to obtain an aqueous solution.

[0077] S3. Add all the oil phase solution and aqueous phase solution obtained in S1 and S2 into the emulsification tank, emulsify for 20 minutes, then transfer to the reaction vessel, stir with nitrogen, heat to 65℃ for 4 hours, heat to 85℃ for 2 hours, and then cool to 50℃ to obtain the crude product.

[0078] S4. Filter and separate the crude product described in S3, dry and pulverize the filtered solid to obtain polymer microspheres 5.

[0079] Example 6

[0080] S1. Weigh 80 parts by weight of methyl methacrylate, 2 parts by weight of methacrylic acid, 18 parts by weight of trimethylolpropane trimethacrylate and 1 part by weight of benzoyl peroxide and add them to reactor A. Stir and disperse until completely dissolved to obtain an oil phase solution.

[0081] S2. Weigh 1000 parts by weight of deionized water and 2 parts by weight of allyloxynonylphenol polyoxyethylene ether (10) ammonium sulfate and add them to reactor B. Stir and disperse until completely dissolved to obtain an aqueous solution.

[0082] S3. Add all the oil phase solution and aqueous phase solution obtained in S1 and S2 into the emulsification tank, emulsify for 60 min, then transfer to the reaction vessel, stir with nitrogen, heat to 65℃ for 8 hours, heat to 85℃ for 2 hours, and then cool to 50℃ to obtain the crude product.

[0083] S4. Filter and separate the crude product described in S3, dry and pulverize the filtered solid to obtain polymer microspheres 6.

[0084] Comparative Example 1:

[0085] The steps are the same as in Example 1, except that an equal amount of non-reactive surfactant (sodium dodecyl sulfonate) is used instead of polyethylene glycol (2000) monomethyl ether methacrylate allyloxy fatty alcohol polyoxyethylene ether (20) ammonium sulfonate. Microspheres cannot be obtained during the polymerization process and all of them are precipitated.

[0086] Comparative Example 2:

[0087] The steps are the same as in Example 1, except that an equal amount of the reactive surfactant sodium styrene sulfonate is used to replace polyethylene glycol (2000) monomethyl ether methacrylate allyloxy fatty alcohol polyoxyethylene ether (20) ammonium sulfonate. Microspheres cannot be obtained during the polymerization process and all of them are precipitated.

[0088] Performance testing:

[0089] The properties of the polymer microspheres were characterized using the following methods:

[0090] (1) Microstructure: The polymer microspheres prepared by the above method were analyzed by scanning electron microscopy and trinocular polarized optical microscopy.

[0091] (2) Particle size: Take 0.50g of polymer microspheres prepared by the above method and 0.50g of surfactant and add them to 50g of deionized water. After ultrasonic dispersion for 10min, the particle size is measured by Omec laser particle size analyzer.

[0092] (3) Thermal properties: The polymer microspheres prepared by the above method were tested by thermogravimetric analyzer. The test conditions were: temperature 30-500℃, heating rate 15℃ / min, nitrogen gas, and flow rate 20mL / min.

[0093] SEM images of the polymer microspheres prepared in Example 4 are shown below. Figure 1 As shown, the electron microscope image is as follows. Figure 2 As shown in Table 1, the particle size and thermal performance measurement results of each embodiment are shown in Table 1.

[0094] Table 1

[0095]

[0096] from Figure 1 and Figure 2 It can be seen that the polymer microspheres prepared by the present invention have smooth surfaces and good sphericity. Table 1 shows that the polymer microspheres prepared by the method of the present invention have a narrow particle size distribution, with an average particle size not exceeding 20 μm. Furthermore, they exhibit good thermal properties, with thermal decomposition temperatures all above 300℃.

[0097] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A polymer microsphere containing surfactant units, characterized in that, The polymer microspheres are produced by suspension polymerization, and the polymer microspheres contain the following units. composition: A: Oil phase unit B: Reactive surfactant unit, C: Initiator unit, The oil phase unit comprises residues formed by the reaction of polymeric monomers and crosslinking monomers; the mass ratio of polymeric monomers to crosslinking monomers is 50~99.5:0.5~50. The reactive surfactant unit is formed from the residues of the reactive surfactant after reaction. The reactive surfactant is one or more of allyloxynonylphenol polyoxyethylene ether sulfate, allyloxy aromatic alcohol polyoxyethylene ether sulfonate, allyloxy fatty alcohol polyoxyethylene ether sulfonate, and alkyl olefin polyoxyethylene ether phosphate. The mass of the reactive surfactant unit is 0.1-10% of the mass of the oil phase unit. The initiator unit is formed from the residues after the initiator reaction.

2. The polymer microspheres according to claim 1, characterized in that, The polymerizing monomer is one or more of styrene, α-methylstyrene, ethyl acrylate, butyl acrylate, isobutyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, glycidyl methacrylate, acrylic acid, itaconic acid, dibutyl maleate, dioctyl maleate, acrylamide, methacrylamide, acrylonitrile, ethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, dimethylaminoethyl methacrylate, or 2-hydroxypropyl methacrylate.

3. The polymer microspheres according to claim 1, characterized in that, The mass ratio of the polymeric monomer to the crosslinking monomer is 60~99:1~40.

4. The polymer microspheres according to claim 1, characterized in that, The crosslinking monomer is one or more of ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, propoxylated triglyceride triacrylate, and dipentaerythritol pentaacrylate.

5. The polymer microspheres according to claim 1, characterized in that, The initiator unit is a residue formed by an azo initiator or a peroxide initiator.

6. The method for preparing the polymer microspheres according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Preparation of oil phase solution: Mix the polymerizing monomer, crosslinking monomer, and initiator to prepare an oil phase solution; S2. Preparation of aqueous solution: Deionized water and reactive surfactant are mixed to prepare an aqueous solution; the amount of reactive surfactant is 0.1~10% of the total mass of the polymerizing monomer and crosslinking monomer; S3. Mix and emulsify the oil phase solution and aqueous phase solution obtained in S1. and S2., add them to the reaction vessel, stir the reaction under nitrogen gas, and after the reaction is completed, ripen and cool to obtain the crude product; S4. Separate the crude product described in S3., dry the solid, and pulverize it to obtain polymer microspheres.

7. The method for preparing polymer microspheres according to claim 6, characterized in that, In S2, the amount of reactive surfactant used is 0.2 to 5% of the total mass of the polymerizing monomer and the crosslinking monomer.

8. The method for preparing polymer microspheres according to claim 6, characterized in that, In S2, the amount of deionized water and the mass ratio of the total mass of polymerizing monomers to crosslinking monomers are 1.5~15:

1.

9. The method for preparing polymer microspheres according to claim 6, characterized in that, In S3, the reaction temperature is between 20 and 70°C.

10. The method for preparing polymer microspheres according to claim 6, characterized in that, In S3, the ripening is carried out at 75~90°C.

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