A kind of polymer hollow microsphere and preparation method thereof

Abstract

The present invention discloses a kind of polymer hollow microsphere and its preparation method, which consists of an external organic shell layer and a hollow structure inside the shell layer, and the particle size of the hollow microsphere is 0.5-100 μm; The volume of the hollow structure is 10-90% of the volume of the hollow microsphere. The preparation method comprises the following steps: (1) dissolving a photocurable material and a poor solvent in a good solvent and mixing them by vortex oscillation as an oil phase; an aqueous dispersion of an emulsifier is used as the aqueous phase; (2) the aqueous phase and the oil phase are mixed and emulsified to obtain an emulsion; (3) removing the good solvent in the emulsion, and then placing the emulsion in a photocuring system, irradiating it to cure a microsphere emulsion with a core-shell structure, and removing the poor solvent to obtain the polymer hollow microsphere. The polymer hollow microsphere of the present invention can be used to prepare a thermal insulation coating, and the reduction of the thermal conductivity of the coating can be achieved by regulating the morphology of the microspheres and the amount of addition.

Description

Technical Field

[0001] The present invention relates to the technical field of microspheres, in particular to a polymer hollow microsphere and a preparation method thereof. Background Art

[0002] Polymer hollow microspheres are microspheres with a hollow structure inside, and their shell is composed of polymer. Polymer hollow microspheres have the characteristics of low density, high specific surface area, adjustable structure and high loading efficiency. They have high application value and broad application prospects in the fields of coatings, leather fabrics, biomedicine and energy catalysis.

[0003] Currently, a variety of strategies have been proposed for the preparation of polymer hollow microspheres, including template synthesis, emulsion polymerization, self-assembly, and microfluidics. The template method is a relatively mature technical method. By introducing template particles and polymerizing them on their surface, and then removing the template, hollow microspheres with adjustable cavity size can be obtained. However, template removal involves the use of an etchant, and the preparation steps are complicated. Emulsion polymerization is also a commonly used industrial technology for the preparation of polymer hollow microspheres. By introducing a seed polymer that is incompatible with the shell polymer and co-dissolving it with the shell monomer in a continuous phase emulsion droplet containing an initiator, this method limits the polymerization of the shell monomer to the emulsion interface, resulting in hollow microspheres with a relatively uniform shell thickness. The prepared emulsion microspheres do not require post-processing.

[0004] However, both of the above preparation technologies require the introduction of certain sacrificial templates. The preparation and removal of the templates are time-consuming and energy-consuming. In addition, under the curing method mainly based on thermal polymerization, the reaction temperature for producing polymer hollow microspheres is generally high and the synthesis time is long. These problems limit the development and practical application of the template method and emulsion method for synthesizing hollow microspheres. Summary of the Invention

[0005] In response to the above-mentioned problems existing in the prior art, the present invention provides a polymer hollow microsphere and a preparation method thereof. The present invention uses a poor solvent for the polymer as a template, and simultaneously disperses an oil phase containing a photocurable prepolymer, a photocurable reactive diluent, a photoinitiator, a good solvent for the polymer, and the poor solvent in an aqueous phase to form emulsion droplets of relatively uniform size. After the good solvent evaporates, the phase separation of the poor solvent and the prepolymer drives the microspheres to form a core-shell structure. In this process, the core-shell ratio can be controlled by adjusting the ratio of the photocurable prepolymer to the poor solvent. Furthermore, efficient and energy-saving photocuring is used as the curing method, and the poor solvent is removed by washing to prepare polymer hollow microspheres with a stable cavity structure and a uniform shell.

[0006] The technical solutions of the present invention are as follows:

[0007] The first object of the present invention is to provide a polymer hollow microsphere, which is composed of an external organic shell layer and a hollow structure inside the shell layer. The particle size of the polymer hollow microsphere is 0.5-100 μm; the organic shell layer is a photocurable polymer with a thickness of 0.1-50 μm; the volume of the hollow structure in the hollow microsphere is 10-90% of the volume of the hollow microsphere.

[0008] A second object of the present invention is to provide a method for preparing the hollow polymer microspheres, the method comprising the following steps:

[0009] (1) dissolving a photocurable material and a poor solvent in a good solvent and mixing them by vortex oscillation as the oil phase; and an aqueous dispersion of an emulsifier as the water phase;

[0010] (2) The water phase and the oil phase are mixed and emulsified to prepare an emulsion;

[0011] (3) removing the good solvent from the emulsion, and then placing the emulsion in a light curing system, irradiating and curing it to obtain a microsphere emulsion with a core-shell structure, and after removing the poor solvent, the polymer hollow microspheres are obtained.

[0012] In one embodiment of the present invention, in step (1), the photocurable material includes a photocurable resin prepolymer, a photocurable monomer, and a photoinitiator.

[0013] In one embodiment of the present invention, in step (1), the photocurable material includes 10-40 parts of photocurable resin prepolymer, 0-4 parts of photocurable monomer, and 0.1-5 parts of photoinitiator; each raw material is calculated by weight fraction.

[0014] In one embodiment of the present invention, in step (1), the photocurable resin prepolymer is one or more of polyurethane acrylate, polyester acrylate, epoxy acrylate or its derivatives, methacrylate, and methacrylate derivatives;

[0015] In one embodiment of the present invention, the polyurethane acrylate is one or more of aliphatic polyurethane diacrylate, aliphatic polyurethane tetraacrylate, aliphatic polyurethane hexaacrylate, and aliphatic polyurethane decaacrylate.

[0016] In one embodiment of the present invention, in step (1), the photocurable monomer is one or more of trimethylolpropane triacrylate, pentaerythritol triacrylate, and (propoxy)glycerol triacrylate.

[0017] In one embodiment of the present invention, in step (1), the photoinitiator is one or more of 2-hydroxy-2-methylphenylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, bis(1-(2,4-difluorophenyl)-3-pyrrolyl)titanocene, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone.

[0018] In one embodiment of the present invention, in step (1), the good solvent is one or more of dichloromethane, toluene, ethyl acetate, and acetone.

[0019] In one embodiment of the present invention, in step (1), the poor solvent is one or more of cyclohexane, n-pentane, n-heptane, and anhydrous ether.

[0020] In one embodiment of the present invention, in step (1), the amount of the good solvent is 40-70 parts, and the amount of the poor solvent is 10-40 parts; the amount of each raw material is calculated in parts by weight.

[0021] In one embodiment of the present invention, in step (1), the emulsifier is one or more of polyvinyl alcohol, sodium lauryl sulfonate, sodium lauryl sulfate, and hexadecyltrimethylammonium bromide.

[0022] In one embodiment of the present invention, in step (1), the mass concentration of the aqueous dispersion of the emulsifier is 0.5-5%.

[0023] Preferably, the mass concentration of the aqueous dispersion of the emulsifier is 2%.

[0024] In one embodiment of the present invention, in step (2), the oil phase is slowly added to the water phase, and the mixture is emulsified at high speed for 3-10 minutes using a homogenizer to prepare an emulsion.

[0025] Preferably, the mass ratio of the oil phase to the water phase is 1:4-10.

[0026] Preferably, a homogenizer is used for emulsification at a rotation speed of 3000-10000 rpm.

[0027] In one embodiment of the present invention, in step (3), the emulsion obtained in step (2) is stirred at 25-40° C. for 4-24 hours to volatilize the good solvent, and then the emulsion is placed in a light curing system for radiation curing, and finally the poor solvent is removed to obtain the polymer hollow microspheres.

[0028] In one embodiment of the present invention, in step (3), the light curing system is UV light curing, the UV light source wavelength is 230-420 nm, and the irradiation curing time is 1-10 min.

[0029] In one embodiment of the present invention, the particle size of the polymer hollow microspheres is 0.5-100 μm.

[0030] In one embodiment of the present invention, the volume of the hollow structure in the polymer hollow microspheres is 10-90% of the volume of the hollow microspheres.

[0031] The third object of the present invention is to provide an application of the polymer hollow microspheres for preparing a thermal insulation coating.

[0032] The beneficial technical effects of the present invention are:

[0033] The present invention prepares emulsion droplets with a core-shell structure by solvent volatile phase separation of a good solvent and a poor solvent, does not require the introduction of a template, and uses light curing technology to prepare microspheres. Microspheres with a hollow structure can be obtained in a one-pot process without heating.

[0034] The present invention can adjust the thickness of the shell layer by changing the ratio of the poor solvent to the light-curing material, and the operation is simple.

[0035] The prepared polymer hollow microspheres are used as fillers to prepare heat-insulating coatings. By regulating the morphology of the microspheres and the amount of addition, the thermal conductivity of the coating can be reduced to a minimum of 0.0506 W / (m·K). BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a scanning electron microscope characterization image of the polymer hollow microspheres in Example 1;

[0037] Figure 2 This is a scanning electron microscope characterization image of the polymer hollow microspheres in Example 2;

[0038] Figure 3 This is a scanning electron microscope characterization image of the polymer hollow microspheres in Example 3;

[0039] Figure 4 This is a scanning electron microscope characterization image of the polymer solid microspheres in Comparative Example 1;

[0040] Figure 5 This is a scanning electron microscope characterization image of the polymer solid microspheres in Comparative Example 2;

[0041] Figure 6 This is a scanning electron microscope characterization image of the polymer solid microspheres in Comparative Example 3;

[0042] Figure 7 This is a scanning electron microscope characterization image of the polymer solid microspheres in Comparative Example 4;

[0043] Figure 8 is the thermal conductivity of the coating filled with polymer hollow microspheres in Application Example 1;

[0044] Figure 9is the thermal conductivity of the coating filled with polymer hollow microspheres in Application Example 2. DETAILED DESCRIPTION

[0045] The present invention will be described in detail below in conjunction with the accompanying drawings and Examples. The present invention can be better understood based on the following examples. However, it is readily understood by those skilled in the art that the specific material proportions, process conditions, and results thereof described in the examples are merely illustrative of the present invention and should not, and will not, limit the present invention described in detail in the claims.

[0046] Example 1

[0047] A method for preparing hollow polymer microspheres comprises the following steps:

[0048] 33 parts of polyurethane diacrylate, 10.56 parts of cyclohexane, 3.3 parts of trimethylolpropane triacrylate, 2.64 parts of 2-hydroxy-2-methylphenylpropane-1-one, and 44 parts of dichloromethane were added to a 250 mL beaker and vortexed to mix them evenly to obtain an oil phase component; the oil phase was slowly added to 374 parts of an aqueous phase containing 1.87 parts of polyvinyl alcohol (performed in a 500 mL flask), and emulsified at 3000 rpm in a homogenizer for 5 minutes to obtain a polymer emulsion. The prepared emulsion was stirred at 35° C. for 6 hours to evaporate the good solvent, and then the emulsion was placed under a UV-LED ultraviolet light source for curing for 5 minutes. After removing the poor solvent, polymer hollow microspheres were obtained, which was recorded as C / S = 0.2.

[0049] Depend on Figure 1 Scanning electron microscopy photos show that the particle size of the synthesized polymer hollow microspheres is about 20 μm, the shell thickness is about 4 μm, and the core-shell ratio is 0.2.

[0050] Example 2

[0051] A method for preparing hollow polymer microspheres comprises the following steps:

[0052] 33 parts of epoxy acrylate, 19.04 parts of n-pentane, 2.2 parts of pentaerythritol triacrylate, 1.32 parts of bis(1-(2,4-difluorophenyl)-3-pyrrolyl)titanium (784), and 55 parts of ethyl acetate were added to a 250 mL beaker and vortexed to mix them evenly to obtain an oil phase component; the oil phase was slowly added to 1326 parts of an aqueous phase containing 13.3 parts of sodium dodecylsulfonate (carried out in a 500 mL flask), and emulsified at 3000 rpm in a homogenizer for 5 minutes to obtain a polymer emulsion. The prepared emulsion was stirred at 35° C. for 6 hours to evaporate the good solvent, and then the emulsion was placed under a UV-LED ultraviolet light source for curing for 5 minutes. After removing the poor solvent, polymer hollow microspheres were obtained, which was recorded as C / S=0.4.

[0053] Depend on Figure 2 Scanning electron microscope photos show that the particle size of the synthesized polymer solid microspheres is about 20 μm, the shell thickness is about 2 μm, and the core-shell ratio is 0.4.

[0054] Example 3

[0055] A method for preparing hollow polymer microspheres comprises the following steps:

[0056] 33 parts of polyester acrylate, 40 parts of n-heptane, 1.1 parts of (propyloxy)glycerol triacrylate, 0.66 parts of 1-hydroxycyclohexyl phenyl ketone, and 67 parts of dichloromethane were added to a 250 mL beaker and vortexed to mix them evenly to obtain an oil phase component; the oil phase was slowly added to 1134 parts of an aqueous phase containing 22.7 parts of sodium lauryl sulfate (carried out in a 500 mL flask), and emulsified at 3000 rpm in a homogenizer for 5 minutes to obtain a polymer emulsion. The prepared emulsion was stirred at 35° C. for 6 hours to evaporate the good solvent, and then the emulsion was placed under a UV-LED ultraviolet light source for curing for 5 minutes. After removing the poor solvent, polymer hollow microspheres were obtained.

[0057] Depend on Figure 3 Scanning electron microscopy images show that the particle size of the synthesized polymer solid microspheres is about 20 μm, the shell thickness is about 1.5 μm, and the core-shell ratio is 0.8, which is denoted as C / S=0.8.

[0058] Figure 1-3 The hollow polymer microspheres synthesized in Example 1, Example 2, and Example 3 are shown. As can be seen from this series of figures, the hollow microspheres have a distinct spherical structure, and there is no obvious depression or collapse on the surface of the microspheres. Different addition ratios of poor solvents to prepolymers can form hollow microspheres with different core-shell ratios. As the proportion of the poor solvent increases, the wall thickness decreases.

[0059] Example 4

[0060] A method for preparing hollow polymer microspheres comprises the following steps:

[0061] 10 parts of polyester acrylate, 19.04 parts of cyclohexane, 1 part of pentaerythritol triacrylate, 0.66 parts of 2-hydroxy-2-methylphenylpropane-1-one, and 66 parts of ethyl acetate were added to a 250 mL beaker and vortexed to mix them evenly to obtain an oil phase component; the oil phase was slowly added to 582 parts of an aqueous phase containing 5.8 parts of sodium lauryl sulfate (carried out in a 500 mL flask), and emulsified at 3000 rpm in a homogenizer for 5 minutes to obtain a polymer emulsion. The prepared emulsion was stirred at 35° C. for 6 hours to evaporate the good solvent, and then the emulsion was placed under a UV-LED ultraviolet light source for curing for 5 minutes. After removing the poor solvent, polymer hollow microspheres were obtained.

[0062] Example 5

[0063] A method for preparing hollow polymer microspheres comprises the following steps:

[0064] 40 parts of polyester acrylate, 23.01 parts of cyclohexane, 4 parts of trimethylolpropane triacrylate, 3.28 parts of 2-hydroxy-2-methylphenylpropane-1-one, and 70 parts of dichloromethane were added to a 250 mL beaker and vortexed to mix them evenly to obtain an oil phase component; the oil phase was slowly added to 562 parts of an aqueous phase containing 28 parts of sodium lauryl sulfate (carried out in a 500 mL flask), and emulsified at 3000 rpm in a homogenizer for 5 minutes to obtain a polymer emulsion. The prepared emulsion was stirred at 35° C. for 6 hours to evaporate the good solvent, and then the emulsion was placed under a UV-LED ultraviolet light source for curing for 5 minutes. After removing the poor solvent, polymer hollow microspheres were obtained.

[0065] Example 6

[0066] A method for preparing hollow polymer microspheres comprises the following steps:

[0067] 33 parts of polyurethane diacrylate, 10.56 parts of cyclohexane, 2.64 parts of 2-hydroxy-2-methylphenylpropane-1-one, and 44 parts of dichloromethane were added to a 250 mL beaker and vortexed to mix them evenly to obtain an oil phase component; the oil phase was slowly added to 374 parts of an aqueous phase containing 1.87 parts of polyvinyl alcohol (carried out in a 500 mL flask), and emulsified at 3000 rpm in a homogenizer for 5 minutes to obtain a polymer emulsion. The prepared emulsion was stirred at 35° C. for 6 hours to evaporate the good solvent, and then the emulsion was placed under a UV-LED ultraviolet light source for curing for 5 minutes. After removing the poor solvent, polymer hollow microspheres were obtained.

[0068] Comparative Example 1

[0069] A method for preparing polymer solid microspheres comprises the following steps:

[0070] 33 parts of polyurethane tetraacrylate, 2.2 parts of pentaerythritol triacrylate, 0.66 parts of 1-hydroxycyclohexyl phenyl ketone, and 55 parts of dichloromethane were added to a 250 mL beaker and vortexed to mix them evenly to obtain an oil phase component; the oil phase was slowly added to 908 parts of an aqueous phase containing 40 parts of sodium lauryl sulfate (performed in a 500 mL flask), and emulsified at 3000 rpm in a homogenizer for 5 minutes to obtain a polymer emulsion. The prepared emulsion was stirred at 35° C. for 6 hours to evaporate the good solvent, and then the emulsion was placed under a UV-LED ultraviolet light source for curing for 5 minutes. After removing the poor solvent, polymer solid microspheres were obtained, which were recorded as C / S=0.

[0071] Depend on Figure 4 Scanning electron microscope photos show that the particle size of the synthesized polymer solid microspheres is about 20 μm and there is no cavity structure.

[0072] Comparative Example 2

[0073] A method for preparing eccentric hollow polymer microspheres comprises the following steps:

[0074] 33 parts of polyester acrylate, 38.04 parts of anhydrous ether, 3.3 parts of trimethylolpropane triacrylate, 0.56 parts of 2-hydroxy-2-methylphenylpropane-1-one, and 62 parts of toluene were added to a 250 mL beaker and vortexed to mix them evenly to obtain an oil phase component; the oil phase was slowly added to 821 parts of an aqueous phase containing 32.8 parts of hexadecylammonium bromide (carried out in a 500 mL flask), and emulsified at 3000 rpm in a homogenizer for 5 minutes to obtain a polymer emulsion. The prepared emulsion was stirred at 35° C. for 6 hours to evaporate the good solvent, and then the emulsion was placed under a UV-LED ultraviolet light source for curing for 5 minutes. After removing the poor solvent, polymer hollow microspheres were obtained.

[0075] Depend on Figure 5 Scanning electron microscope photos show that the particle size of the synthesized polymer eccentric hollow microspheres is about 20 μm, the wall thickness of the microspheres is not uniform, and they have an eccentric structure.

[0076] Comparative Example 3

[0077] A method for preparing polymer multi-core hollow microspheres comprises the following steps:

[0078] 33 parts of epoxy acrylate, 20 parts of n-heptane, 4.23 parts of 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, and 47 parts of toluene were added to a 250 mL beaker and vortexed to mix them evenly to obtain an oil phase component; the oil phase was slowly added to 833 parts of an aqueous phase containing 16.7 parts of sodium lauryl sulfate (carried out in a 500 mL flask), and emulsified at 3000 rpm in a homogenizer for 5 minutes to obtain a polymer emulsion. The prepared emulsion was stirred at 35° C. for 6 hours to evaporate the good solvent, and then the emulsion was placed under a UV-LED ultraviolet light source for curing for 5 minutes. After removing the poor solvent, polymer hollow microspheres were obtained.

[0079] Depend on Figure 6 Scanning electron microscope photos show that the particle size of the synthesized polymer multi-core hollow microspheres is about 20 μm, and the cavity contains multiple polymer microspheres, presenting a multi-core structure.

[0080] Comparative Example 4

[0081] A method for preparing polymer porous microspheres comprises the following steps:

[0082] 39 parts of trimethylolpropane triacrylate, 39 parts of cyclohexane, 0.66 parts of bis(1-(2,4-difluorophenyl)-3-pyrrolyl)titanium, and 66 parts of ethyl acetate were added to a 250 mL beaker and vortexed to mix them evenly to obtain an oil phase component; the oil phase was slowly added to 1446 parts of an aqueous phase containing 7 parts of polyvinyl alcohol (carried out in a 500 mL flask), and emulsified at 3000 rpm in a homogenizer for 5 minutes to obtain a polymer emulsion. The prepared emulsion was stirred at 35° C. for 6 hours to evaporate the good solvent, and then the emulsion was placed under a UV-LED ultraviolet light source for curing for 5 minutes. After removing the poor solvent, polymer hollow microspheres were obtained.

[0083] Depend on Figure 7 Scanning electron microscope photos show that the particle size of the synthesized polymer porous microspheres is about 20 μm, and the micropore size is between 100-500 nm.

[0084] Application Example 1

[0085] Preparation of thermal insulation coating based on polymer hollow microspheres

[0086] The hollow polymer microspheres with different core-shell ratios prepared in Examples 1-3 (C / S=0.2, C / S=0.4, C / S=0.8) and Comparative Example 1 (C / S=0) were added in an amount of 10 wt% to a photocurable resin system (3 g modified epoxy acrylate, 4 g polyester acrylate, 2.5 g isobornyl acrylate, 0.2 g 2-hydroxy-2-methyl-1-phenylpropanone, 0.2 g hydroxyethyl methacrylate phosphate, 0.1 g polyether modified dimethylsiloxane). After being thoroughly mixed, they were coated on a steel plate using a 120 μm frame scraper, and then placed under a UV light source for curing for 3 minutes to obtain a thermal insulation coating.

[0087] like Figure 8 As shown in the figure, the thermal conductivity of the thermal insulation coating decreases with the increase of the core-shell ratio of the hollow microspheres. Since at the same addition amount, the number of hollow microspheres and the total volume of the cavity increase with the increase of the core-shell ratio, the thermal insulation performance of the coating will be improved when the core-shell ratio is increased. The thermal conductivity of the pure resin coating is 0.251W / (m·K), the thermal conductivity of the microsphere composite coating with a core-shell ratio of 0 is 0.1635W / (m·K), the thermal conductivity of the microsphere composite coating with a core-shell ratio of 0.2 is 0.1494W / (m·K), the thermal conductivity of the microsphere composite coating with a core-shell ratio of 0.4 is 0.1148W / (m·K), and the thermal conductivity of the microsphere composite coating with a core-shell ratio of 0.8 is 0.0716W / (m·K).

[0088] Application Example 2

[0089] Preparation of thermal insulation coating based on polymer hollow microspheres

[0090] The specific process of the preparation method of the thermal insulation coating based on polymer hollow microspheres involved in this embodiment is the same as that of Application Example 1, except that the polymer hollow microspheres prepared in Example 2 have a C / S of 0.4 and are added in amounts of 5wt%, 10wt%, 20wt%, and 30wt%, respectively.

[0091] like Figure 9 As shown in the figure, the thermal conductivity of the thermal insulation coating decreases with the increase of the amount of hollow microspheres added. Since the hollow microspheres contain gas cavities with low thermal conductivity, as the amount of polymer hollow microspheres added increases, the total volume of the cavities increases, and the coating has a stronger heat barrier effect, so it has a lower thermal conductivity. The thermal conductivity of the pure resin coating is 0.2466W / (m·K), the thermal conductivity of the composite coating with 5% microspheres added is 0.1375W / (m·K), the thermal conductivity of the composite coating with 10% microspheres added is 0.1148W / (m·K), the thermal conductivity of the composite coating with 20% microspheres added is 0.0949W / (m·K), and the thermal conductivity of the composite coating with 30% microspheres added is 0.0777W / (m·K).

[0092] The embodiments provided above are not intended to limit the scope of the present invention, nor are the steps described to limit their execution order. Any obvious improvements to the present invention made by those skilled in the art in combination with existing common knowledge shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A polymer hollow microsphere, consisting of an outer organic shell and a hollow structure inside the shell, characterized in that: The particle size of the polymer hollow microspheres is 0.5-100 μm; the organic shell layer is a photocurable polymer with a thickness of 0.1-50 μm; the volume of the hollow structure in the hollow microspheres is 10-90% of the volume of the hollow microspheres; The preparation method of the hollow polymer microspheres comprises the following steps: (1) The photocurable material and the poor solvent are mixed in a good solvent to form the oil phase; the aqueous dispersion of the emulsifier is used as the water phase; The photocurable material comprises 10-40 parts of photocurable resin prepolymer, 1-4 parts of photocurable monomer, and 0.1-5 parts of photoinitiator; each raw material is calculated in parts by weight; The good solvent is used in an amount of 40-70 parts, and the poor solvent is used in an amount of 10-40 parts; the amount of each raw material is calculated in parts by weight; (2) The water phase and the oil phase are mixed and emulsified to prepare an emulsion; the mass ratio of the oil phase to the water phase is 1:4-10; (3) removing the good solvent from the emulsion, and then placing the emulsion in a light curing system, irradiating and curing it to obtain a core-shell structured microsphere emulsion, and after removing the poor solvent, the polymer hollow microspheres are obtained.

2. A method for preparing the hollow polymer microspheres according to claim 1, characterized in that: The preparation method comprises the following steps: (1) The photocurable material and the poor solvent are mixed in a good solvent to form the oil phase; the aqueous dispersion of the emulsifier is used as the water phase; The photocurable material comprises 10-40 parts of photocurable resin prepolymer, 1-4 parts of photocurable monomer, and 0.1-5 parts of photoinitiator; each raw material is calculated in parts by weight; The good solvent is used in an amount of 40-70 parts, and the poor solvent is used in an amount of 10-40 parts; the amount of each raw material is calculated in parts by weight; (2) The water phase and the oil phase are mixed and emulsified to prepare an emulsion; the mass ratio of the oil phase to the water phase is 1:4-10; (3) removing the good solvent from the emulsion, and then placing the emulsion in a light curing system, irradiating and curing it to obtain a core-shell structured microsphere emulsion, and after removing the poor solvent, the polymer hollow microspheres are obtained.

3. The preparation method according to claim 2, characterized in that In step (1), the photocurable resin prepolymer is one or more of polyurethane acrylate, polyester acrylate, and epoxy acrylate; The photocurable monomer is one or more of trimethylolpropane triacrylate, pentaerythritol triacrylate, and (propoxy)glycerol triacrylate; The photoinitiator is one or more of 2-hydroxy-2-methylphenylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, bis(1-(2,4-difluorophenyl)-3-pyrrolyl)titanocene, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone.

4. The preparation method according to claim 2, characterized in that In step (1), the good solvent is one or more of dichloromethane, toluene, ethyl acetate, and acetone; the poor solvent is one or more of cyclohexane, n-pentane, n-heptane, and anhydrous ether; and the emulsifier is one or more of polyvinyl alcohol, sodium dodecyl sulfonate, sodium lauryl sulfate, and hexadecyltrimethylammonium bromide.

5. The preparation method according to claim 2, characterized in that In step (2), the oil phase is slowly added to the water phase, and the mixture is emulsified at high speed using a homogenizer for 3-10 minutes to obtain an emulsion.

6. The preparation method according to claim 2, characterized in that In step (3), the light curing system is UV light curing, the UV light source wavelength is 230-420nm, and the irradiation curing time is 1-10min.

7. An application of the hollow polymer microspheres according to claim 1, characterized in that: Used to prepare thermal insulation coatings.

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