Resin microspheres for sensitizing emulsion explosives and their application

Abstract

The invention discloses resin microspheres for sensitizing emulsion explosives. The resin microspheres are prepared by suspension polymerization to form heat-expandable microspheres with acrylic resin as a shell and a foaming agent as a core, and the heat-expandable microspheres are modified by a Pickering emulsion method to obtain resin microspheres with an amphiphilic asymmetric Janus structure. The pumping stability of the emulsion explosive is improved while the basic properties of the microspheres are not lost. The surfaces of the modified resin microspheres have hydrophilic polyethylene glycol chains and hydrophobic alkyl chains. The amphiphilic structure can be directional arranged at an oil-water interface, with the hydrophobic surface facing the oil phase and the hydrophilic surface facing the water phase. The directional adsorption can form a stronger interface film and enhance the emulsion stability.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to resin microspheres for sensitizing emulsion explosives and applications thereof. Background Art

[0002] Resin microspheres are polymer particles with a core-shell structure, which usually contain low-boiling alkanes inside and slightly cross-linked thermoplastic polymers outside. When the resin microspheres are heated, the hydrocarbon substances inside vaporize to generate pressure, and the capsule wall softens at the same time. If the thermoplasticity of the capsule wall and the pressure generated by the vaporization of the internal hydrocarbons are properly matched, the microcapsules can show good expansion performance.

[0003] Emulsion explosives are the most widely used industrial explosives in China. At present, the emulsion explosives industry generally uses sensitization methods such as chemical sensitization, physical sensitization, and composite sensitization. Among them, physical sensitization is to add a large amount of gas-carrying substances into the latex matrix, and use the bubbles carried by the substance to achieve the sensitization of the emulsion explosives. Resin microspheres have good thermomechanical properties, excellent elasticity and compressive resistance, can reduce the density of emulsion explosives, excellent chemical resistance, and excellent foaming properties. It has become an excellent choice for sensitized emulsion explosives. At present, the main technical indicators for evaluating the quality of emulsion explosives include density, explosive performance, and storage performance, but there are few studies on the pumping stability of emulsion explosives by resin microsphere structure. The pumping stability of emulsion explosives is a parameter that characterizes its dynamic stability in production. During the production process of emulsion explosives, the conveying devices such as screw pumps and vane pumps on the production line will destroy its stable structure, resulting in different degrees of crystal precipitation, thickening, hardening, and other problems. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the present invention adopts suspension polymerization to prepare heat-expandable microspheres with acrylic resin as the shell and foaming agent as the core, and adopts the Pickering emulsion method to modify the heat-expandable microspheres to obtain amphiphilic asymmetric Janus structure resin microspheres, which can improve the pumping stability of emulsion explosives while ensuring that the basic properties of the microspheres are not lost.

[0005] The technical solution for achieving the purpose of the present invention is as follows:

[0006] The resin microspheres used for sensitizing emulsion explosives, the preparation method of the resin microspheres is as follows:

[0007] S1. Add a pH regulator, an inorganic salt and a surfactant to deionized water and stir to form a stable suspension protective solution;

[0008] S2. In an inert gas atmosphere, hydroxyethyl methacrylate, methyl methacrylate, acrylonitrile, an initiator, and a crosslinking agent are mixed and prepolymerized at 70 to 80 ° C, then cooled to room temperature, a blowing agent is added and mixed, and then dispersed in the suspension protection liquid obtained in S1, stirred for a period of time, and then continued to react at 70 to 80 ° C for a period of time, and then cooled, filtered, washed, and dried to obtain heat-expandable microspheres;

[0009] S3. Dispersing paraffin and didodecyl dimethyl ammonium bromide in deionized water to obtain a paraffin dispersion liquid, dispersing the heat-expandable microspheres obtained in S2 in deionized water, and then adding the paraffin dispersion liquid, wherein the mass ratio of the paraffin to the heat-expandable microspheres is 1: (10-20); stirring at a temperature of 65-75°C for a period of time, cooling to room temperature, and after the paraffin solidifies, washing with deionized water and ethanol, and vacuum drying at 30-40°C to obtain partially covered heat-expandable microspheres;

[0010] S4. In an inert gas atmosphere, the partially covered heat-expandable microspheres obtained in S3 and 3-glycidyloxypropyltriethoxysilane are dispersed in an aqueous solution of 1 to 2 wt.% ethanol, stirred at a temperature of 35 to 40 ° C for 2 to 3 days, washed with deionized water and ethanol, and then dispersed in a chloroform solution and filtered, and the surface paraffin is removed by repeating at least three times to obtain heat-expandable microspheres partially modified with epoxy groups;

[0011] S5. In an inert gas atmosphere, the partially modified epoxy group heat-expandable microspheres obtained in S4 and alkyl triethoxysilane were dispersed in an aqueous solution of 97 to 98 wt.% ethanol, stirred at a temperature of 50 to 60 ° C for 2 to 3 d, washed with deionized water and ethanol to obtain heat-expandable microspheres modified with alkyl and epoxy groups;

[0012] S6. Under an inert gas atmosphere, the alkyl and epoxy group-modified heat-expandable microspheres obtained in S5 are dispersed in tetrahydrofuran solvent, aminopolyethylene glycol monomethyl ether and triethylamine are added, and after stirring at 50-60°C for 12-24h, the microspheres are washed with deionized water and ethanol to obtain resin microspheres.

[0013] It should be noted that the epoxy structure and the ethoxysilane structure in the present invention can react with hydroxyl groups, so great attention should be paid to the reaction temperature and the selection of catalyst.

[0014] Specifically, the suspension protection solution in step S1 includes 1.0-1.5 parts of a pH regulator, 3.0-4.5 parts of an inorganic salt, 0.4-2.0 parts of a surfactant, and 25-50 parts of deionized water.

[0015] Preferably, the pH adjuster is one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide; the inorganic salt is magnesium chloride hexahydrate; the surfactant is at least one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate; more preferably, the pH adjuster in step S1 is sodium hydroxide; the surfactant is sodium dodecyl sulfate.

[0016] Specifically, the proportions of the raw materials in step S2 are 1-2 parts of hydroxyethyl methacrylate, 4-8 parts of methyl methacrylate, 5-10 parts of acrylonitrile, 0.2-0.4 parts of initiator, 0.1-0.2 parts of cross-linking agent, and 2.5-5.0 parts of foaming agent.

[0017] Preferably, the initiator is one or more of dibenzoyl peroxide, potassium persulfate, lauroyl peroxide and azobisisobutyronitrile; the crosslinking agent is one or more of 1,4-butanediol dimethacrylate, 1,4-butanediol diacrylate and 1,4-butanediol divinyl ether; the foaming agent is one or more of n-butane, isobutane, n-pentane, isopentane, 2,3-dimethylbutane, 3-methylpentane, n-hexane, cyclohexane and petroleum ether.

[0018] More preferably, in step S2, the initiator is azobisisobutyronitrile; the cross-linking agent is 1,4-butanediol dimethacrylate; and the blowing agent is isobutane.

[0019] Preferably, in step S3, the mass ratio of paraffin wax to didodecyldimethylammonium bromide is 1:1.

[0020] Preferably, in step S4, the mass ratio of the partially covered heat-expandable microspheres to 3-glycidyloxypropyltriethoxysilane is 1:(0.4-0.5).

[0021] Preferably, in step S5, the mass ratio of the heat-expandable microspheres partially modified with epoxy groups to the alkyltriethoxysilane is 1:(0.4-0.5); the alkyltriethoxysilane has the following molecular structure of formula I:

[0022] Wherein n=6-16, preferably, n=10-16.

[0023] Preferably, in step S6, the mass ratio of the heat-expandable microspheres modified with alkyl and epoxy groups to the aminopolyethylene glycol monomethyl ether is 1:(0.4-0.5); the average molecular weight of the aminopolyethylene glycol monomethyl ether is 200-1000; preferably, the average molecular weight of the aminopolyethylene glycol monomethyl ether is 200-400.

[0024] Another object of the present invention is to protect the application of the resin microspheres in emulsion explosives.

[0025] The present invention also provides an emulsion explosive, which comprises the following components in parts by mass:

[0026] Ammonium nitrate: 75-80 parts;

[0027] Sodium nitrate: 4.5-5.0 parts;

[0028] Water: 10-12 parts;

[0029] Emulsifier: 21-23 parts;

[0030] Oil phase: 3.5-4.5 parts;

[0031] Resin microspheres: 0.4-1.0 parts; the resin microspheres are the above-mentioned resin microspheres.

[0032] Preferably, the emulsion explosive comprises 0.6 to 0.8 parts of the above-mentioned resin microspheres.

[0033] The present invention also provides a method for preparing an emulsion explosive, comprising the following steps: adding ammonium nitrate and sodium nitrate into water, heating and dissolving to form a water phase, and controlling the temperature at 85-95°C; heating and melting a composite oil phase, and also controlling the temperature at 85-95°C; placing the oil phase in an emulsifier, and controlling the stirring speed to be 1000-1200 r / min; adding a water phase into the oil phase while stirring, emulsifying for 3 minutes, stopping the machine to discharge the material, and obtaining an emulsified matrix; placing resin microspheres in an environment of 80-120°C to foam for 5-10 minutes, adding the microspheres into the emulsified matrix, and mixing and stirring evenly to obtain an emulsion explosive.

[0034] Beneficial Effects

[0035] The present invention has the following beneficial effects: The present invention provides heat-expandable microspheres prepared by suspension polymerization with acrylic resin as the shell and foaming agent as the core, and the heat-expandable microspheres are modified by Pickering emulsion method to obtain resin microspheres with amphiphilic asymmetric Janus structure, which can improve the pumping stability of emulsion explosives while ensuring that the basic properties of the microspheres are not lost. The surface of the modified resin microspheres has hydrophilic polyethylene glycol chains and hydrophobic alkyl chains. This amphiphilic structure can be oriented at the oil-water interface, with the hydrophobic surface facing the oil phase and the hydrophilic surface facing the water phase. This oriented adsorption can form a stronger interface film and enhance the stability of the emulsion. After grafting on the surface of the microspheres, the interaction between the microspheres and the friction with the dispersion medium can be reduced, and the viscosity of the system can be reduced to a certain extent, so that it has good processing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the synthetic route of the resin microspheres of the present invention.

[0037] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0039] The raw materials and equipment used in the embodiments and comparative examples are described as follows:

[0040] Hydroxyethyl methacrylate: product number H810855, purchased from Shanghai MacLean Biochemical Technology;

[0041] Methyl methacrylate: product number M813513, purchased from Shanghai MacLean Biochemical Technology;

[0042] Acrylonitrile: product number A875361, purchased from Shanghai MacLean Biochemical Technology;

[0043] Paraffin: Product No. A01127, purchased from Wuhan Jiyesheng Chemical Co., Ltd.;

[0044] Didodecyl dimethyl ammonium bromide: product number D806878, purchased from Shanghai MacLean Biochemical Technology;

[0045] 3-Glycidyloxypropyltriethoxysilane: Product No. G832117, purchased from Shanghai MacLean Biochemical Technology;

[0046] Isobutane: product number M300826, purchased from Shanghai Aladdin Biochemical Technology;

[0047] Sodium dodecyl sulfate: product number S6077, purchased from Shanghai MacLean Biochemical Technology;

[0048] 4-Azobisisobutyronitrile: product number A800353, purchased from Shanghai MacLean Biochemical Technology;

[0049] 1,4-Butanediol dimethacrylate: Product No. G832117, purchased from Shanghai MacLean Biochemical Technology;

[0050] n-Octyltriethoxysilane: product number T819170, purchased from Shanghai MacLean Biochemical Technology;

[0051] Dodecyltrimethoxysilane: product number D830295, purchased from Shanghai MacLean Biochemical Technology;

[0052] Octadecyltrimethoxysilane: product number T917281, purchased from Shanghai MacLean Biochemical Technology;

[0053] Polyethylene glycol monomethyl ether 1: average molecular weight 200, purchased from Shanghai MacLean Biochemical Technology;

[0054] Polyethylene glycol monomethyl ether 2: average molecular weight 550, purchased from Shanghai MacLean Biochemical Technology;

[0055] Polyethylene glycol monomethyl ether 3: average molecular weight 1000, purchased from Shanghai MacLean Biochemical Technology.

[0056] Aminopolyethylene glycol monomethyl ether 1 (self-made): In a nitrogen atmosphere, add 1 mol of polyethylene glycol monomethyl ether 1 with an average molecular weight of 200, 3 mol of p-toluenesulfonyl chloride (Annaiji Chemical, product number T35955), and 3 mol of triethylamine to a Shrek bottle, use dichloromethane as solvent, stir at 50°C for 10 hours, and wait for the reaction to end. First wash three times with 1 mol / L hydrochloric acid solution, then wash three times with 1 mol / L sodium hydroxide aqueous solution, collect the organic phase, and evaporate;

[0057] The obtained solid was dissolved in ammonia water, stirred at room temperature for three days, then a 2 mol / L sodium hydroxide aqueous solution was added and stirring was continued for 2 hours, extracted three times with dichloromethane, the organic phase was collected, evaporated, and recrystallized from ether to obtain aminoethylene glycol monomethyl ether with an average molecular weight of 200.

[0058] Aminopolyethylene glycol monomethyl ether 2

[0059] The preparation method is compared with aminopolyethylene glycol monomethyl ether 1, in which 1 mol of polyethylene glycol monomethyl ether 1 with an average molecular weight of 200 is replaced by 1 mol of polyethylene glycol monomethyl ether 2 with an average molecular weight of 550.

[0060] Aminopolyethylene glycol monomethyl ether 3

[0061] The preparation method is compared with aminopolyethylene glycol monomethyl ether 1, in that 1 mol of polyethylene glycol monomethyl ether 1 with an average molecular weight of 200 is replaced by 1 mol of polyethylene glycol monomethyl ether 3 with an average molecular weight of 1000.

[0062] Resin microspheres 1

[0063] S1. 1.2 parts of pH regulator, 4.0 parts of inorganic salt and 0.8 parts of sodium dodecyl sulfate were added to 50 parts of deionized water and stirred for 1 hour to form a stable suspension protective solution;

[0064] S2. Under an inert gas atmosphere, 2 parts of hydroxyethyl methacrylate, 8 parts of methyl methacrylate, 10 parts of acrylonitrile, 0.4 parts of initiator, and 0.2 parts of crosslinking agent were mixed and prepolymerized at 75°C for 5 minutes, then quickly cooled to 25°C, 5.0 parts of isobutane were added and evenly mixed, and then dispersed in the suspension protection solution obtained in S1, stirred at 500-700 rpm for 5 minutes, and then continued to react at 75°C for 6 hours. After cooling, filtering, washing, and drying, unmodified heat-expandable microspheres were obtained;

[0065] S3. Disperse 1 part of paraffin wax and 1 part of didodecyl dimethyl ammonium bromide in 100 parts of deionized water to obtain a paraffin dispersion liquid, disperse 1 part of the heat-expandable microspheres obtained in S2 in 90 parts of deionized water, and then add 10 parts of the paraffin dispersion liquid, stir at a temperature of 70°C for 35 minutes, cool to room temperature, and after the paraffin is solidified, wash with deionized water and ethanol in turn, and vacuum dry at 35°C for 24 hours to obtain partially covered heat-expandable microspheres;

[0066] S4. Under an inert gas atmosphere, 2 parts of ethanol, 98 parts of deionized water, 1 part of the partially covered heat-expandable microspheres obtained in S3, and 0.4 parts of 3-glycidyloxypropyltriethoxysilane were stirred at a temperature of 35°C for 2d, washed with deionized water and ethanol in sequence, and then dispersed in a chloroform solution and filtered, and the surface paraffin was removed three times to obtain heat-expandable microspheres with partially modified epoxy groups;

[0067] S5. Under an inert gas atmosphere, 2 parts of deionized water, 98 parts of ethanol, 1 part of the partially epoxy-modified heat-expandable microspheres obtained in S4, and 0.4 parts of n-octyltriethoxysilane were stirred at a temperature of 50 to 60 ° C for 3d and washed with deionized water and ethanol in turn to obtain heat-expandable microspheres modified with alkyl and epoxy groups;

[0068] S6. Under an inert gas atmosphere, 1 part of the alkyl- and epoxy-modified heat-expandable microspheres obtained in S5 was dispersed in 40 parts of tetrahydrofuran solvent, and then 0.4 parts of aminopolyethylene glycol monomethyl ether 1 and 0.04 parts of triethylamine were added. After stirring at 55°C for 18 hours, the mixture was washed with deionized water and ethanol in turn to obtain amphiphilic Janus-structured resin microspheres 1.

[0069] Resin microspheres 2

[0070] The preparation method is different from the resin microsphere 1 in that n-octyltriethoxysilane is replaced by dodecyltrimethoxysilane in step S5.

[0071] Resin microspheres 3

[0072] The preparation method is different from the resin microsphere 1 in that n-octyltriethoxysilane is replaced by octadecyltrimethoxysilane in step S5.

[0073] Resin microspheres 4

[0074] The preparation method is different from the resin microsphere 3 in that the aminopolyethylene glycol monomethyl ether 1 is replaced by aminopolyethylene glycol monomethyl ether 2 in step S6.

[0075] Resin microspheres 5

[0076] The preparation method is different from the resin microsphere 3 in that the aminopolyethylene glycol monomethyl ether 1 is replaced by aminopolyethylene glycol monomethyl ether 3 in step S6.

[0077] The following is the test method of the performance parameters involved in the present invention:

[0078] Microsphere expansion ratio determination: Using a metallographic analysis system, the diameters of about 300 heat-expandable microcapsules at the initial expansion temperature and the contraction temperature were measured, and the average particle sizes of the microspheres before and after foaming were calculated, which were d0 and d0, respectively. The microsphere expansion ratio was obtained as d / d0;

[0079] Average particle size of microspheres: weigh about 1g of washed and dried microcapsules, add about 30mL of deionized water, stir evenly and disperse by ultrasonic for 3min; measure the average particle size of microspheres by laser particle size analyzer;

[0080] Foaming performance test of microspheres: Take a certain amount of dry microcapsules, evenly disperse them on a cover glass, and place them on a precision thermostatic hot stage. Heat the hot stage at a rate of 10°C / min and film the foaming process. According to the readings on the precision thermostatic hot stage, record the initial expansion temperature and contraction temperature, and calculate the stable foaming temperature range based on this;

[0081] Pumping stability of emulsion explosives: The emulsion explosives were repeatedly pumped 8 times, and the changes in the colloid were observed microscopically;

[0082] Emulsion explosive viscosity: Brookfield DV-I viscometer (5-axis, 10r / min) was used to measure the viscosity at a temperature of 30-70°C.

[0083] Stability of emulsion explosive system: Take 50g of emulsion explosive and place it in a watch glass. After being tested at different temperatures (-12~38℃) and humidity (35%~90%) throughout the year, measure the resistance of different samples once a month with a conductivity meter to observe the state changes.

[0084] Table 1 Foaming properties and average particle size of resin microspheres

[0085]

[0086]

[0087] The preparation method of the emulsion explosive is as follows: adding ammonium nitrate and sodium nitrate into water, heating and dissolving to form a water phase, and controlling the temperature at 85-95°C; heating and melting the composite oil phase, and also controlling the temperature at 85-95°C; placing the oil phase in an emulsifier, and controlling the stirring speed to be 1000r / min; adding the water phase to the oil phase while stirring, emulsifying for 3 minutes, stopping the machine to discharge the material, and obtaining an emulsified matrix; placing the resin microspheres in a 100°C environment to foam for 5 minutes, adding them to the emulsified matrix, and mixing and stirring evenly to obtain the emulsion explosive.

[0088] Table 2 Emulsion explosive formula (unit / part, Examples 1 to 10)

[0089]

[0090] Table 3 Emulsion explosive formula (unit / part, comparative examples 1 to 3)

[0091] Comparative Example 1 Comparative Example 2 Comparative Example 3 Ammonium Nitrate 77 77 77 Sodium nitrate 4.7 4.7 4.7 water 11 11 11 Emulsifier 22 22 22 oil phase 4.0 4.0 4.0 Resin microspheres 1 0.2 1.5 Unmodified heat-expandable microspheres 0.8

[0092] Table 4 Properties of emulsion explosives

[0093]

[0094]

[0095] From the data in Table 1, it can be seen that the foaming performance of resin microspheres 1 to 5 is similar to that of unmodified heat-expandable microspheres, the expansion temperature and the contraction temperature are slightly increased, and the stable foaming temperature range is slightly increased; the foaming ratio and the average particle size are basically unchanged; this shows that modifying the surface of the resin microspheres will not have a significant effect on their foaming performance.

[0096] It can be seen from the data of Examples 3 to 6 in Table 4 that with the increase of the content of resin microspheres in the emulsion explosive, its pumping stability gradually increases, the system stability first increases and then decreases, and the viscosity gradually increases; it can be seen from the data of Examples 5, 7, 8, 9, and 10 that the longer the alkyl chain and the polyethylene glycol chain modified on the surface of the resin microspheres in the system, the better the pumping stability of the system and the lower the viscosity, but because the polyethylene glycol chain has the characteristic of absorbing water, the insulation performance of the system is reduced and the stability of the system is relatively low; it can be seen from the data of Comparative Examples 1 to 2 that too much or too little addition of resin microspheres will lead to a decrease in the performance of the emulsion explosive; it can be seen from the data of Comparative Example 3 that the addition of unmodified thermal expansion microspheres will result in poor pumping stability of the emulsion explosive and excessive viscosity, which will affect its processing performance, but because no water-absorbing polyethylene glycol group is introduced, the system stability is relatively high.

[0097] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. Resin microspheres for sensitizing emulsion explosives, characterized in that: The preparation method of the resin microspheres is as follows: S1. Add a pH regulator, an inorganic salt and a surfactant to deionized water and stir to form a stable suspension protective solution; S2. In an inert gas atmosphere, hydroxyethyl methacrylate, methyl methacrylate, acrylonitrile, an initiator, and a crosslinking agent are mixed and prepolymerized at 70 to 80 ° C, then cooled to room temperature, a blowing agent is added and mixed, and then dispersed in the suspension protection liquid obtained in S1, stirred for a period of time, and then continued to react at 70 to 80 ° C for a period of time, and then cooled, filtered, washed, and dried to obtain heat-expandable microspheres; S3. Dispersing paraffin and didodecyl dimethyl ammonium bromide in deionized water to obtain a paraffin dispersion liquid, dispersing the heat-expandable microspheres obtained in S2 in deionized water, and then adding the paraffin dispersion liquid, wherein the mass ratio of the paraffin to the heat-expandable microspheres is 1: (10-20); stirring at a temperature of 65-75°C for a period of time, cooling to room temperature, and after the paraffin solidifies, washing with deionized water and ethanol, and vacuum drying at 30-40°C to obtain partially covered heat-expandable microspheres; S4. In an inert gas atmosphere, the partially covered heat-expandable microspheres obtained in S3 and 3-glycidyloxypropyltriethoxysilane were dispersed in an aqueous solution of 1.0 to 2.0 wt.% ethanol, stirred at a temperature of 35 to 40 ° C for 2 to 3 days, washed with deionized water and ethanol, and then dispersed in a chloroform solution and filtered, and the surface paraffin was removed by repeating at least three times to obtain heat-expandable microspheres with partially modified epoxy groups; S5. In an inert gas atmosphere, the partially modified epoxy group heat-expandable microspheres obtained in S4 and alkyl triethoxysilane were dispersed in an aqueous solution of 97 to 98 wt.% ethanol, stirred at a temperature of 50 to 60 ° C for 2 to 3 d, washed with deionized water and ethanol to obtain heat-expandable microspheres modified with alkyl and epoxy groups; S6. Under an inert gas atmosphere, the alkyl and epoxy group-modified heat-expandable microspheres obtained in S5 are dispersed in tetrahydrofuran solvent, aminopolyethylene glycol monomethyl ether and triethylamine are added, and after stirring at 50-60°C for 12-24h, the microspheres are washed with deionized water and ethanol to obtain resin microspheres.

2. The resin microspheres according to claim 1, characterized in that The suspension protection solution in step S1 includes 1.0-1.5 parts of a pH regulator, 3.0-4.5 parts of an inorganic salt, 0.4-2.0 parts of a surfactant, and 25-50 parts of deionized water; the pH regulator is one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide; the inorganic salt is magnesium chloride hexahydrate; and the surfactant is at least one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

3. The resin microspheres according to claim 1, characterized in that The proportions of the raw materials in step S2 are 1 to 2 parts of hydroxyethyl methacrylate, 4 to 8 parts of methyl methacrylate, 5 to 10 parts of acrylonitrile, 0.2 to 0.4 parts of initiator, 0.1 to 0.2 parts of cross-linking agent, and 2.5 to 5.0 parts of foaming agent; the initiator is one or more of dibenzoyl peroxide, potassium persulfate, lauroyl peroxide, and azobisisobutyronitrile; the cross-linking agent is one or more of 1,4-butanediol dimethacrylate, 1,4-butanediol diacrylate, and 1,4-butanediol divinyl ether; the foaming agent is one or more of n-butane, isobutane, n-pentane, isopentane, 2,3-dimethylbutane, 3-methylpentane, n-hexane, cyclohexane, and petroleum ether.

4. The resin microspheres according to claim 1, characterized in that In step S3, the mass ratio of paraffin wax to didodecyl dimethyl ammonium bromide is 1:

1.

5. The resin microspheres according to claim 1, characterized in that In step S4, the mass ratio of the partially covered heat-expandable microspheres to 3-glycidyloxypropyltriethoxysilane is 1:(0.4-0.5).

6. The resin microspheres according to claim 1, characterized in that In step S5, the mass ratio of the heat-expandable microspheres partially modified with epoxy groups to the alkyltriethoxysilane is 1:(0.4-0.5); the alkyltriethoxysilane has the following molecular structure of formula I: Wherein n=6~16.

7. The resin microspheres according to claim 1, characterized in that In step S6, the mass ratio of the heat-expandable microspheres modified with alkyl and epoxy groups to aminopolyethylene glycol monomethyl ether is 1:(0.4-0.5); the average molecular weight of the aminopolyethylene glycol monomethyl ether is 200-1000.

8. Use of the resin microspheres according to any one of claims 1 to 7 in emulsion explosives.

9. Emulsion explosive, characterized in that In parts by mass, it includes the following components: Ammonium nitrate: 75-80 parts; Sodium nitrate: 4.5-5.0 parts; Water: 10-12 parts; Emulsifier: 21-23 parts; Oil phase: 3.5-4.5 parts; Resin microspheres: 0.4-1.0 parts; the resin microspheres are the resin microspheres according to any one of claims 1-7.

10. The method for preparing the emulsion explosive according to claim 9, characterized in that: The method comprises the following steps: adding ammonium nitrate and sodium nitrate into water, heating and dissolving to form a water phase, and controlling the temperature at 85-95 DEG C; heating and melting a composite oil phase, and also controlling the temperature at 85-95 DEG C; placing the oil phase in an emulsifier, and controlling the stirring speed to be 1000-1200 r / min; adding a water phase into the oil phase while stirring, emulsifying for 3 minutes, stopping the machine to discharge the material, and obtaining an emulsified matrix; placing resin microspheres in an environment of 80-120 DEG C to foam for 5-10 minutes, and adding the microspheres into the emulsified matrix, mixing and stirring evenly, and obtaining an emulsified explosive.

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