A sulfur microsphere capsule, its preparation method and application

Abstract

The present invention discloses a sulfur microsphere capsule, a preparation method thereof and an application thereof, belonging to the technical field of polymer materials. The sulfur microsphere capsule provided by the present invention has a core-shell structure, wherein the shell is a POSS hybrid cross-linked polymer structure with a glass transition temperature of 132-165 °C, and the core is sulfur; the POSS hybrid cross-linked polymer structure includes a vinyl copolymer monomer and a cage-type polyhedral oligomeric silsesquioxane; the sulfur microsphere capsule provided by the present invention has a clear surface, good shape regularity and small particle size, between 1.18-3.06 μm; the glass transition temperature of the shell layer is 132-165 °C, and this temperature range is higher than the rubber mixing temperature of 100-130 °C, so that the sulfur microsphere capsule of the present invention can be applied to the rubber vulcanization field to avoid the blooming phenomenon; at the same time, the preparation method of the sulfur microsphere capsule provided by the present invention is simple, the production is convenient, and the raw materials are inexpensive, which is suitable for actual industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a sulfur microsphere capsule, a preparation method thereof and an application thereof. Background Art

[0002] Sulfur is an element widely distributed in nature. The solid powder is called sulfur and exists in various mineral structures and fossil fuels. During the process of mineral extraction or fossil fuel refining, strict desulfurization treatment is required, generating a large amount of sulfur powder. Sulfur has a wide range of applications in the chemical industry, and its applications cover many aspects such as sulfuric acid manufacturing, rubber vulcanization, papermaking, fungicides and dyes in the chemical industry. However, sulfur is prone to sublimation, and the sublimated sulfur and sulfur powder floating in the air are extremely easy to explode when encountering sparks in the air. In addition, sulfur is easily oxidized into sulfur dioxide in the air, and sulfur dioxide combines with moisture in the air to form sulfurous acid. Sulfurous acid has a relatively large irritation to the lungs and is also very easy to further oxidize, ultimately forming sulfuric acid. Sulfuric acid is the main component of acid rain. It can be seen that the safe treatment, application and storage of sulfur are of great significance to the current environmental and industrial fields.

[0003] Currently, a method is to gasify sulfur at high temperature for polymerization crystallization treatment to form insoluble crystalline sulfur aggregates. The products are mainly those of Flexsys in foreign countries. There is also domestic production, and the performance is gradually approaching that of foreign products. However, this method consumes a large amount of energy, and the stability of crystalline polymerized sulfur is poor, with unstable performance. Sulfur is a very important vulcanizing agent in rubber products. Ordinary sulfur is prone to "blooming" on the surface of rubber products, which is a relatively serious quality problem in the rubber industry. Therefore, it is very necessary to inhibit rubber blooming. The main reason for blooming is that sulfur is unevenly dispersed in the rubber and is prone to agglomeration. The sulfur powder in the agglomeration only undergoes vulcanization with the sulfur in contact with the rubber during the vulcanization process, and the sulfur powder inside the agglomeration fails to react with the rubber. Due to the low melting point of sulfur, it starts to overflow to the surface of the rubber during the vulcanization process, producing white frost. At the same time, the uniformity of rubber vulcanization will also be affected, thus affecting the product quality. To solve the blooming problem, insoluble crystalline polymerized sulfur is used instead, but the cost is relatively high. Application No. 200910180589.7 discloses a raw material formula for producing sulfur microcapsules that can be used as a rubber vulcanizing agent. It consists of sublimed sulfur, urea, 37% formaldehyde solution, gelatin or polyvinyl alcohol, formic acid, triethanolamine, and water. Sulfur microcapsule products are prepared by in-situ polymerization. At a certain temperature, the coating shell melts and releases sulfur, which can play a role in vulcanizing rubber. Application No. 200910005110.6 discloses a raw material formula for producing double-layer film sulfur microcapsules. It consists of sublimed sulfur, toluene diisocyanate, water, ethylenediamine, diethylenetriamine, urea, and formaldehyde. Double-layer film sulfur microcapsules are prepared by interfacial polymerization. Its core material is sublimed sulfur, and the first-layer coating material is the interfacial polymerization product of ethylenediamine, diethylenetriamine, and toluene diisocyanate; the second-layer coating material is urea-formaldehyde resin, and the particle size of this kind of capsule exceeds 100μm. Similarly, there are reports of using emulsion polymerization to coat sulfur with polyvinyl alcohol, vinyl acetate and vinyltriethoxysilane copolymer, polyethylene wax, etc. The particle size is generally above 100μm. The second category is the polymer high-molecular physical coating method. Existing water-soluble polymers are used and emulsifiers are added for sulfur coating. Generally, the particles are relatively large after coating, and it is difficult to coat tightly. The melting point of the shell is also very low. For example, the patent of Application No. 201110203772.1 uses high-molecular substances such as stearic acid, polyethylene resins, and natural rubber for coating. The patent of Application No. 201210224588.X uses water-soluble polymers such as gelatin and cyclodextrin and natural polymers such as gum arabic and xanthan gum for sulfur coating. The third category is the inorganic particle physical coating technology. Inorganic particles are added, together with emulsifiers, and then mixed with sulfur for coating, and then dried. The drying temperature of the inorganic substances is high, and they agglomerate after drying and need to be crushed and sieved. Crushing also damages the coating; therefore, it is very difficult to achieve uniform and effective coating. The patent of Application No. 201510306288.X uses SiO 2The product particles are coated with a thin film and a polymer film layer, and the particle size is 6.3 - 15 μm. For the patent with the application number 201510289745.9, inorganic silica is used as the shell layer for sulfur coating, and the prepared particles have a particle size of 0.8 - 5 μm. In the preparation process of this kind of inorganic material coating, due to particle re - aggregation during the drying process, the powder needs to be milled and crushed, and then sieved again, which will damage the coated capsules and result in irregular morphology. Another example is the patent with the application number 201610410842.3, where inorganic powder is mixed with water, a modifier is added to form a coating emulsion, and then added to the inorganic powder suspension, and sulfur is added after stirring evenly to prepare modified sulfur; this will also make the morphology irregular. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to overcome the deficiencies of the above - mentioned prior art and provide a sulfur microsphere capsule with small particle size, high glass transition temperature of the shell layer, clear surface, and regular morphology, as well as its preparation method and application.

[0005] To achieve the above - mentioned purpose, the technical solution adopted by the present invention is as follows: A sulfur microsphere capsule, the sulfur microsphere capsule has a core - shell structure, the shell is a POSS hybrid cross - linked polymer structure with a glass transition temperature of 132 - 165 °C, and the core is sulfur; the POSS hybrid cross - linked polymer structure includes the following components: vinyl copolymer monomer and cage - type polyhedral oligomeric silsesquioxane.

[0006] The sulfur microsphere capsule provided by the present invention adopts a hybrid cross - linking method, utilizing the hydrogen - bond interaction and the synergistic effect of cage - type polyhedral oligomeric silsesquioxane hybrid cross - linking copolymerization. It can not only effectively improve the glass transition temperature of the shell layer, making the glass transition temperature of the obtained product between 132 - 165 °C, but also realize the amphiphilic properties of the sulfur microsphere capsule through the selection of vinyl copolymer monomers; at the same time, the sulfur microsphere capsule with a core - shell structure provided by the technical solution of the present invention has a smaller particle size, between 1.18 - 3.06 μm, and has a clear surface and good shape regularity.

[0007] As a preferred embodiment of the sulfur microsphere capsule of the present invention, in the core - shell structure, the mass ratio of the core to the shell is core: shell=(80 - 90):(10 - 20); for example, in the present invention, the mass ratio of the core to the shell can be 80:10, 80:12, 80:15, 80:18, 80:20, 85:10, 85:12, 85:15, 85:18, 85:20, 90:10, 90:12, 90:15, 90:18, 90:20, etc.

[0008] The inventors have found that the mass ratio of the core to the shell in the sulfur microsphere capsule will affect the particle size and stability. If the mass of the core is too much and the shell is thin, it will be easily broken by squeezing during the application process. If the mass of the core is too little, the effect of subsequent use will be reduced. And because the core is cheap sulfur, in order to achieve the corresponding economic effect, the quality of the core layer is made as relatively high as possible, that is, excellent uniformity and regularity can be achieved when the quality of the core layer is high.

[0009] As a preferred embodiment of the sulfur microsphere capsule of the present invention, the mass ratio of the vinyl comonomer to the cage-type polysilsesquioxane is vinyl comonomer: cage-type polysilsesquioxane=100:(1-10).

[0010] Preferably, the mass ratio of the vinyl comonomer to the cage-type polysilsesquioxane is vinyl comonomer: cage-type polysilsesquioxane=100:(2.5-8).

[0011] The inventors have found that the mass ratio of the vinyl comonomer to the cage-type polysilsesquioxane will affect the appearance and structure of the product. If the mass of the vinyl comonomer is too much, the cross-linking density of the microspheres will be insufficient, which is not conducive to tight coating. If the mass of the vinyl comonomer is too little, the flexibility of the microspheres will be affected and the cost will increase. When the mass ratio of the vinyl comonomer to the cage-type polysilsesquioxane is 100:(1-10), especially 100:(2.5-8), the comprehensive performance of the obtained sulfur microsphere capsule is optimal.

[0012] As a preferred embodiment of the sulfur microsphere capsule of the present invention, the cage-type polysilsesquioxane is a vinyl-terminated cage-type polysilsesquioxane or a cage-type polysilsesquioxane containing a reactive functional terminal group. Specifically, the cage-type polysilsesquioxane is at least one of octaaminopropyl cage-type polysilsesquioxane and its derivatives, octa-glycidyl cage-type polysilsesquioxane and its derivatives, octacarboxyethylene cage-type polysilsesquioxane and its derivatives, and octamethacryloxypropyl cage-type polysilsesquioxane and its derivatives.

[0013] Preferably, the cage-type polysilsesquioxane is octamethacryloxypropyl cage-type polysilsesquioxane (MMA-POSS).

[0014] As a preferred embodiment of the sulfur microsphere capsule of the present invention, the vinyl comonomer is at least one of styrene and its derivatives, methyl methacrylate and its derivatives, hydroxyethyl methacrylate and its derivatives, hydroxyethyl methyl acrylate and its derivatives, vinyl acrylate and its derivatives, methacrylamide and its derivatives, glycidyl methacrylate and its derivatives, methacrylic acid and its derivatives, octyl methacrylate and its derivatives, and butyl methacrylate and its derivatives.

[0015] Preferably, the vinyl comonomer is a composite of styrene and hydroxyethyl methacrylate, wherein the mass ratio of styrene to hydroxyethyl methacrylate is (1 - 3):(1 - 3).

[0016] As a preferred embodiment of the sulfur microsphere capsule of the present invention, the particle size of the sulfur microsphere capsule is 1.1 - 3.1 μm; in the present invention, the particle size of the sulfur microsphere capsule can be 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm, 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3.0 μm, 3.1 μm, etc.

[0017] In addition, the present invention also provides a method for preparing the sulfur microsphere capsule, and the preparation method includes the following steps: sulfur, a dispersant, and a vinyl comonomer are sequentially added to a first organic solvent and dispersed evenly, and then a radical initiator and an acetone solution of cage-type polyhedral oligomeric silsesquioxane are added to obtain a reaction system. The reaction system is reacted at a temperature of 50 - 90 °C for 6 - 24 h under a protective gas environment. After the reaction is completed, filtration, washing, and drying are carried out to obtain the sulfur microsphere capsule.

[0018] As a preferred embodiment of the preparation method of the present invention, the first organic solvent is at least one of toluene, THF, DMF, acetone, 1,4-dioxane; the dispersant is a mixture of a second organic solvent and a stabilizer, and the stabilizer is at least one of sodium octadecyl carboxylate, polyvinyl alcohol (PVA), polymethylbenzene amide, carboxymethyl cellulose, gelatin, sodium alginate, silicon dioxide suspension, and the second organic solvent is at least one of DMF, carbon disulfide, THF, toluene; the radical initiator is an azo initiator and / or an organic peroxide initiator.

[0019] Preferably, the azo initiator is at least one of azodiisobutyronitrile and azodiisooctanenitrile; the organic peroxide initiator is at least one of cumene hydroperoxide, dicumyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, tert-butyl benzoyl peroxide, diisopropyl peroxydicarbonate.

[0020] As a preferred embodiment of the preparation method of the present invention, in the reaction system, the ratio of the total mass of the first organic solvent, the second organic solvent, and acetone to the total mass of sulfur, the stabilizer, the vinyl comonomer, the radical initiator, and the cage-type polyhedral oligomeric silsesquioxane is (4 - 10):1; the mass of the stabilizer accounts for 0.01 - 0.5% of the total mass of the reaction system.

[0021] Under the reaction conditions provided by the present invention, the reaction yield can be guaranteed.

[0022] As a preferred embodiment of the preparation method of the present invention, the washing is carried out with carbon disulfide, and using carbon disulfide can clean and remove the sulfur adsorbed on the surface.

[0023] As a preferred embodiment of the preparation method of the present invention, the drying temperature is 20 - 80 °C, and the drying time is 1 - 10 h.

[0024] As a preferred embodiment of the preparation method of the present invention, the protective gas is an inert gas or nitrogen.

[0025] In addition, the present invention also provides the application of the sulfur microsphere capsules in the fields of rubber safety vulcanizing agents, rubber materials, energy toughening materials, pesticides, fine chemicals, insecticidal and antibacterial agents, or functional materials.

[0026] The sulfur microsphere capsules provided by the present invention have good coating effect, and the coating is tight, and the glass transition temperature of its shell layer is relatively high, at 132 - 165 °C.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] Firstly, the sulfur microsphere capsules provided by the present invention adopt a hybrid cross-linking method, and utilize the hydrogen bond or the chemical hybrid cross-linking copolymerization synergistic effect of cage-like polyhedral oligomeric silsesquioxane. It can not only effectively improve the glass transition temperature of the shell layer and realize the increase of the glass transition temperature. Specifically, the glass transition temperature is 132 - 165 °C, but also can realize the amphiphilic properties of the sulfur microsphere capsules through the selection of vinyl copolymer monomers;

[0029] Secondly, the surface of the sulfur microsphere capsules with a core-shell structure provided by the technical solution of the present invention is clear, the shape regularity is good, and the particle size is small, between 1.1 - 3.1 μm, so as to ensure tight coating;

[0030] Thirdly, the glass transition temperature of the shell layer of the sulfur microsphere capsules provided by the present invention is 132 - 165 °C, and this temperature range is higher than the rubber internal mixing temperature of 100 - 130 °C, so that the sulfur microsphere capsules of the present invention can be applied to the rubber vulcanization field to avoid the blooming phenomenon;

[0031] Fourthly, the preparation method of the sulfur microsphere capsules provided by the present invention is simple, the production is convenient, and the raw materials are inexpensive, which is suitable for actual industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a polarized fluorescence microscope photograph of the sulfur microsphere capsules prepared in Example 1;

[0033] Figure 2 DSC test result diagram of the sulfur microsphere capsules prepared in Example 1. Diagram A is the full-temperature diagram, and Diagram B is the partial enlarged diagram near 160 °C in Diagram A. Detailed implementation manners

[0034] To better illustrate the purpose, technical solutions, and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0035] The raw materials used in the examples and comparative examples of this application are specifically as follows:

[0036] Octamethacryloxypropylcage polyhedral oligomeric silsesquioxane (MMA-POSS): Purchased from Hybrid Plastics, USA, MA0702;

[0037] Octaaminopropylcage polyhedral oligomeric silsesquioxane: Purchased from Hybrid Plastics, USA, AM0270;

[0038] Styrene: Jinan Mingxin Chemical Co., Ltd., 100-42-5;

[0039] 2-Hydroxyethyl methacrylate: Shanghai Chemical Reagent Co., Ltd., 868-77-9;

[0040] Allyl polyether: Guangdong Wengjiang Chemical Reagent Co., Ltd., PA923622;

[0041] In the examples and comparative examples, unless otherwise specified, the experimental methods used are all conventional methods. The materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels. And in parallel experiments, unless otherwise specified, the raw materials used are the same.

[0042] Example 1

[0043] The embodiment of the present invention provides a sulfur microsphere capsule, and the preparation method of the sulfur microsphere capsule is as follows:

[0044] Add 100 parts of industrial sulfur to 200 parts of the first organic solvent (160 parts of toluene and 40 parts of DMF), stir evenly to disperse, then add 20 parts of dispersant (the dispersant is a 2% PVA solution, that is, the mass of the stabilizer PVA accounts for 0.066% of the total mass of the reaction system. The second organic solvent is a mixture of toluene and DMF, and the mass ratio of toluene to DMF is 8:2). After stirring evenly to disperse, add vinyl copolymer monomers (10 parts of styrene and 10 parts of 2-hydroxyethyl methacrylate) and stir for 20 min to disperse evenly. Then add 264.2 parts of an acetone solution containing 0.05 parts of free radical initiator and 0.5 parts of octamethacryloxypropylcage polyhedral oligomeric silsesquioxane to the reaction system. React the reaction system at 65 °C for 15 h under a nitrogen protective gas environment. After the reaction is completed, filter and wash with carbon disulfide. Collect the washed sample and dry it at 60 °C for 6 h to obtain sulfur microsphere capsules.

[0045] Example 2

[0046] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that the vinyl copolymer monomers are changed to 5 parts of styrene and 15 parts of 2-hydroxyethyl methacrylate.

[0047] Example 3

[0048] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that the vinyl copolymer monomers are changed to 15 parts of styrene and 5 parts of 2-hydroxyethyl methacrylate.

[0049] Example 4

[0050] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that the total mass parts of the vinyl copolymer monomers and the cage polyhedral oligomeric silsesquioxane added are the same as those in Example 1, but the vinyl copolymer monomers:cage polyhedral oligomeric silsesquioxane = 100:2.

[0051] Example 5

[0052] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that the total mass parts of the vinyl copolymer monomers and the cage polyhedral oligomeric silsesquioxane added are the same as those in Example 1, but the vinyl copolymer monomers:cage polyhedral oligomeric silsesquioxane = 100:8.

[0053] Example 6

[0054] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that the total mass fraction of the vinyl copolymer monomer and the cage-type polyhedral oligomeric silsesquioxane added is the same as that of Example 1, but the vinyl copolymer monomer:cage-type polyhedral oligomeric silsesquioxane = 100:10.

[0055] Example 7

[0056] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that the reaction system is reacted at a temperature of 90 °C for 6 h in a protective gas environment.

[0057] Example 8

[0058] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that octamethacryloxypropyl cage-type polyhedral oligomeric silsesquioxane is replaced with octaaminopropyl cage-type polyhedral oligomeric silsesquioxane.

[0059] Example 9

[0060] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that 20 parts of styrene is used to replace the vinyl copolymer monomer.

[0061] Example 10

[0062] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that PVA is replaced with a silica suspension.

[0063] Example 11

[0064] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that 160 parts of toluene and 40 parts of 1,4-dioxane are used as the first organic solvent.

[0065] Example 12

[0066] This embodiment provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that the reaction system is reacted at a temperature of 120 °C for 6 h in a protective gas environment.

[0067] Example 13

[0068] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that the concentration of the dispersant added is a 20% PVA solution (that is, the mass of the stabilizer PVA accounts for 0.66% of the total mass of the reaction system).

[0069] Comparative Example 1

[0070] An embodiment of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that no POSS crosslinking agent is added.

[0071] Comparative Example 2

[0072] This comparative example provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that the total mass fraction of the vinyl copolymer monomer and the cage-shaped polyhedral oligomeric silsesquioxane added is the same as that in Example 1, but vinyl copolymer monomer:cage-shaped polyhedral oligomeric silsesquioxane = 100:25.

[0073] Comparative Example 3

[0074] The comparative example of the present invention provides a sulfur microsphere capsule. The only difference between the preparation method of the sulfur microsphere capsule and that of Example 1 is that the vinyl copolymer monomer is replaced by 10 parts of styrene and 10 parts of propylene end-capped polyether.

[0075] Effect Example

[0076] This effect example tests the sulfur microsphere capsules prepared in Examples 1-13 and Comparative Examples 1-3 for morphology testing, particle size measurement, core-shell mass testing, shell glass transition temperature testing, and dispersion performance testing during the rubber vulcanization process.

[0077] The specific testing methods are as follows:

[0078] (1) Testing method for sulfur content: Immerse the coated sulfur in a solvent of CS 2 for 4 h, then filter, evaporate the filtrate to remove CS 2 , weigh to obtain the weight of sulfur in the coating, and divide the weight of sulfur by the weight of the coated microspheres to calculate the sulfur content and the core-shell weight ratio.

[0079] (2) Morphology and sulfur coating property testing of the coated sulfur:

[0080] Since sulfur has fluorescence properties, the core part of the coated particles will exhibit fluorescence characteristics. Therefore, the particle morphology can be observed using a fluorescence polarized microscope, and the uniformity of sulfur coating in the particles or whether sulfur is coated in the particles can be observed using the fluorescence properties of the particles.

[0081] (3) Particle size testing: The particle size can be measured using a fluorescence polarized microscope and magnification, and the statistical average value of the microsphere diameter can be calculated through statistical analysis software.

[0082] (4) Shell glass transition temperature (T g):GB / T 19466.2-2004, using a TA differential scanning calorimeter, N 2 Flow rate 40 mL / min, heating rate 10 °C / min;

[0083] The test results are shown in Table 1;

[0084] Table 1

[0085]

[0086]

[0087] It can be seen from Table 1 that there are differences in the particle size, core-shell mass ratio and morphology of the sulfur microsphere capsules obtained by different preparation methods. When the technical solution of the present invention is adopted, the yield of the obtained sulfur microsphere capsules is above 82%, the sulfur content is above 80%, and the particle size of the obtained sulfur microsphere capsules is between 1.18 - 3.06 μm, the core-shell mass ratio is (80 - 90):(10 - 20), and the glass transition temperature of the shell layer is between 132 - 165 °C; among them, the polarized fluorescence microscope photo of the sulfur microsphere capsules prepared in Example 1 is as Figure 1 shown, and it can be seen from Figure 1 that the particle size of the obtained sulfur microsphere capsules is uniform and has good regularity, and the result graph of its DSC test is as Figure 2 shown.

[0088] It can be seen from Examples 1 - 3 that when the types of vinyl comonomers are the same, the change in their addition amounts will affect the core-shell mass ratio and yield of the finally formed sulfur microsphere capsules, and will also have an impact on the particle size and glass transition temperature of the product. When the mass ratio of styrene and hydroxyethyl methacrylate in the vinyl comonomer used is 1:1, the obtained yield is the best; it can be seen from Example 1, Example 9 and Comparative Example 3 that when different vinyl comonomers are adopted, especially when they are not within the range given in the present invention, the morphology of the obtained product is irregular and the particle size is significantly increased.

[0089] It can be seen from Example 1, Examples 4-6 and Comparative Example 2 that when the total mass parts of the vinyl copolymer monomer and the cage-shaped polyhedral oligomeric silsesquioxane added are kept the same, but their mass ratios are different, as the POSS content increases, the particle regularity begins to decrease. Further increasing the POSS content results in a decrease in yield and a decrease in thermal properties, and it is not uniformly mixed with the rubber. When the mass ratio of the vinyl copolymer monomer to the cage-shaped polyhedral oligomeric silsesquioxane is 100:(1-10), the obtained yield is above 88%, the particle size is between 1.25-2.10 μm, and the glass transition temperature is between 140-165 °C. When the mass ratio of the vinyl copolymer monomer to the cage-shaped polyhedral oligomeric silsesquioxane is further preferably 100:(2.5-8), the obtained yield is above 92%, the particle size is between 1.4-1.52 μm, and the glass transition temperature is above 160 °C, that is, the comprehensive performance is better.

[0090] It can be seen from Example 1, Example 7 and Example 12 that during the preparation process, the reaction temperature and time will also affect the performance of the product. When the reaction temperature is too high, the regularity of the obtained product shows a certain deterioration trend compared with that of Example 1, but overall it is better than the regularity of the product in Comparative Example 1.

[0091] It can be seen from Example 1 and Example 13 that the amount of the dispersant will also affect the regularity of the product. When the mass of the stabilizer in the dispersant is further preferably 0.01-0.5% of the total mass of the reaction system, the obtained particle regularity is excellent; when the mass percentage of the stabilizer in Example 13 is not within the preferred range of the present invention, the regularity of the obtained product shows a certain downward trend compared with that of Example 1, but overall it is better than the regularity of the product in Comparative Example 1.

[0092] It can be seen from Example 1 and Comparative Example 1 that when no POSS cross-linking agent is added, the morphology of the obtained product is irregular, and the yield decreases, the particle size of the product increases, and the glass transition temperature decreases.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and do not limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or replaced with similar material design ideas without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A sulfur microsphere capsule, characterized in that, the sulfur microsphere capsule has a core-shell structure, the shell is a POSS hybrid cross-linked polymer structure with a glass transition temperature of 132-165°C, and the core is sulfur; the POSS hybrid cross-linked polymer structure includes the following components: vinyl copolymer monomer and cage-type polyhedral oligomeric silsesquioxane; the mass ratio of the vinyl copolymer monomer to the cage-type polyhedral oligomeric silsesquioxane is vinyl copolymer monomer:cage-type polyhedral oligomeric silsesquioxane = 100:(1-10); the cage-type polyhedral oligomeric silsesquioxane is at least one of octaaminopropyl cage-type polyhedral oligomeric silsesquioxane, octaepoxypropyl cage-type polyhedral oligomeric silsesquioxane, octacarboxypropyl cage-type polyhedral oligomeric silsesquioxane, octamethacryloxypropyl cage-type polyhedral oligomeric silsesquioxane; the vinyl copolymer monomer is at least one of styrene, methyl methacrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, vinyl acrylate, methacrylamide, glycidyl methacrylate, methacrylic acid, octyl methacrylate, butyl methacrylate.

2. The sulfur microsphere capsule according to claim 1, characterized in that, in the core-shell structure, the mass ratio of the core to the shell is core:shell = (80-90):(10-20).

3. The sulfur microsphere capsule according to claim 1, characterized in that, the particle size of the sulfur microsphere capsule is 1.1-3.1 µm.

4. The preparation method of the sulfur microsphere capsule according to any one of claims 1-3, characterized in that, the preparation method includes the following steps: sulfur, a dispersant and a vinyl copolymer monomer are sequentially added to a first organic solvent and dispersed evenly, then an acetone solution of a radical initiator and a cage-type polyhedral oligomeric silsesquioxane is added to obtain a reaction system, and the reaction system is reacted at a temperature of 50-90°C for 6-24 h in a protective gas environment. After the reaction, filtration, washing and drying are carried out to obtain the sulfur microsphere capsule.

5. The preparation method according to claim 4, characterized in that, the first organic solvent is at least one of toluene, THF, DMF, acetone, 1,4-dioxane; the dispersant is a mixture of a second organic solvent and a stabilizer, the stabilizer is at least one of sodium octadecyl carboxylate, polyvinyl alcohol, carboxymethyl cellulose, gelatin, sodium alginate, silicon dioxide suspension, and the second organic solvent is at least one of DMF, carbon disulfide, THF, toluene; the radical initiator is an azo initiator and / or an organic peroxide initiator.

6. The preparation method according to claim 5, characterized in that, in the reaction system, the ratio of the total mass of the first organic solvent, the second organic solvent and acetone to the total mass of sulfur, the stabilizer, the vinyl copolymer monomer, the radical initiator and the cage-type polyhedral oligomeric silsesquioxane is (4-10):1; the mass of the stabilizer accounts for 0.01-0.5% of the total mass of the reaction system.

7. The application of the sulfur microsphere capsule according to any one of claims 1-3 in the fields of rubber safety vulcanizing agent and rubber materials.

Images