Mining reinforcing material

Abstract

The invention relates to the field of mining materials, in particular to a mining reinforcing material which is used for solving the problems that a traditional reinforcing material often has the defects of insufficient mechanical property, long curing time, poorer flowability and poor flame retardant property and is difficult to meet complex and changeable mine environment requirements. The mining reinforcing material is an organic-inorganic composite mining reinforcing material, the polyurethane matrix and the inorganic reinforcing phase are effectively combined, so that the mining reinforcing material has good fluidity, rapid construction on a mine site is facilitated, and after construction, a cured product of the mining reinforcing material keeps high toughness and meanwhile, the service life of the mining reinforcing material is prolonged, and the service life of the mining reinforcing material is prolonged. The mine reinforcing material has the advantages that the mine reinforcing material has excellent strength performance, can keep stable performance for a long time in a severe mine environment, has good heat-conducting property and flame-retardant property, can quickly export heat to avoid heat accumulation, can effectively inhibit fire spreading, and can meet the mine reinforcing requirement.

Description

Technical Field

[0001] This invention relates to the field of mining materials, and more specifically to a mining reinforcement material. Background Technology

[0002] Coal mine production often encounters geological structures such as faults, folds, and fracture zones, resulting in loose and fragmented coal and rock masses that are highly susceptible to large-scale roof collapses and water inrushes, seriously threatening safe underground production. Therefore, improving the materials and technologies for reinforcing fragmented coal and rock masses is imperative.

[0003] Grouting is the primary method for reinforcing fractured coal and rock masses. Traditional grouting materials can be divided into two main categories: cement-based grouting materials and chemical grouting materials. Cement-based grouting materials have high compressive and tensile strength, providing good structural support and maintaining stable performance over long-term use. However, due to their long curing time, cement-based grouting materials are not suitable for rapid roadway reinforcement, and their poor fluidity makes them difficult to inject into small fissures, failing to meet the long-term stability requirements of the surrounding rock. Chemical grouting materials are polymeric materials, including polyurethane, epoxy resin, and urea-formaldehyde resin. They are mainly injected into the fractures of coal and rock masses through pressure or chemical penetration, achieving high strength in a relatively short time and cementing the loose and fractured surrounding rock into a continuous body. However, chemical reinforcement materials are too expensive, significantly increasing the cost of coal mining and reducing the profits of coal enterprises. Furthermore, they pose significant risks related to reaction temperature, and the materials themselves have poor thermal conductivity, making them prone to heat accumulation during construction, leading to thermal runaway, heat buildup and smoke, and potentially causing underground safety accidents, fires, and other hazards.

[0004] In mining operations, the safety and stability of mine structures are crucial for ensuring safe production. Traditional reinforcement materials often suffer from insufficient mechanical properties, long curing times, poor fluidity, and poor flame retardancy, making them unsuitable for the complex and ever-changing demands of the mining environment. Therefore, developing a mine reinforcement material is of great significance. Summary of the Invention

[0005] In order to overcome the above-mentioned technical problems, the purpose of this invention is to provide a mining reinforcement material that solves the problems that traditional reinforcement materials often have insufficient mechanical properties, long curing time, poor fluidity, and poor flame retardant properties, making it difficult to meet the needs of complex and ever-changing mining environments.

[0006] The objective of this invention can be achieved through the following technical solutions: A mine reinforcement material, comprising component A and component B; The mass ratio of component A to component B is 1:2-4; Component A comprises the following components in parts by weight: 50-70 parts modified isocyanate, 0.25-0.65 parts dibutyltin dilaurate; Component B comprises the following components in parts by weight: The composition comprises 50-60 parts polyether diol, 24-36 parts waste gypsum, 10-18 parts modified expanded graphite, 7-15 parts cement, and 45-65 parts water; the polyether diol is either polyethylene glycol PEG1000 or polypropylene glycol PPG1000; the waste gypsum has a particle size of 100-300 mesh and is either phosphogypsum, desulfurized gypsum, or fluorogypsum; the cement is silicate cement; wherein, the use of waste gypsum as an inorganic filler realizes the resource utilization of waste gypsum, reduces environmental pollution, and the waste gypsum is widely available and inexpensive, thus reducing the production cost of reinforcement materials; The modified isocyanate is prepared by the following steps: Step A1: Add 4-nitro-3-trifluoromethylphenol, hexachlorocyclotriphosphazene, sodium hydroxide, deionized water, and acetone to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and reflux condenser. Purge with nitrogen for protection and stir at 0-5℃ and 300-400 r / min for 1-1.5 h. Then raise the temperature to 25-30℃ and continue stirring for 30-40 min. After that, raise the temperature to reflux and continue stirring for 4-5 h. After the reaction is complete, cool the reaction product to room temperature and add it to ice water. Then vacuum filter the mixture and place the filter cake in a vacuum drying oven at 50-55℃ for 2-3 h to obtain intermediate 1. Step A2: Add intermediate 1, reduced iron powder, hydrochloric acid solution, anhydrous ethanol, anhydrous acetone, and deionized water to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and reflux condenser. Purge with nitrogen for protection and stir at 25-30℃ and a stirring rate of 300-400 r / min for 20-30 min. Then, heat to reflux and continue stirring for 4-5 h. After the reaction is complete, cool the reaction product to room temperature and then vacuum filter. Add the filtrate to ice water and adjust the pH to 7.5-8.5 with sodium hydroxide solution. Allow to stand to precipitate, then vacuum filter. Place the filter cake in a vacuum drying oven and dry at 50-55℃ for 2-3 h to obtain intermediate 2. Step A3: Add intermediate 2,4,4'-diphenylmethane diisocyanate, dibutyltin dilaurate, and N,N-dimethylformamide to a three-necked flask equipped with a stirrer, thermometer, and gas delivery tube. Purge with nitrogen for protection and stir at 25-30°C and a stirring rate of 300-400 r / min for 15-20 min. Then raise the temperature to 50-55°C and continue stirring for 3-5 h. After the reaction is complete, cool the reaction product to room temperature and then place it in a vacuum drying oven at 60-65°C for 3-5 h to obtain modified isocyanate.

[0007] As a further aspect of the present invention: the ratio of 4-nitro-3-trifluoromethylphenol, cyanuric chloride, sodium hydroxide, deionized water and acetone in step A1 is 30 mmol: 5 mmol: 35-40 mmol: 10-12 mL: 60-65 mL.

[0008] As a further aspect of the present invention: the ratio of intermediate 1, reduced iron powder, hydrochloric acid solution, anhydrous ethanol, anhydrous acetone and deionized water in step A2 is 3g:9-13g:0.5-0.9g:8-10mL:8-10mL:8-10mL.

[0009] As a further aspect of the present invention: the mass fraction of the hydrochloric acid solution in step A2 is 10-12%; the mass fraction of the sodium hydroxide solution is 20-25%.

[0010] As a further aspect of the present invention: the ratio of intermediate 2,4,4'-diphenylmethane diisocyanate, dibutyltin dilaurate, and N,N-dimethylformamide in step A3 is 10 mmol: 60 mmol: 0.15-0.25 g: 100-120 mL.

[0011] As a further aspect of the present invention: the modified expanded graphite is prepared by the following steps: Step B1: Add deionized water to a three-necked flask equipped with a thermometer, stirrer, and constant pressure dropping funnel. While stirring at 25-30℃ and a stirring rate of 300-400 r / min, add concentrated sulfuric acid dropwise, controlling the dropping rate to 1-2 drops / s. After the addition is complete, continue stirring for 20-30 min. Then add zinc borate, flake graphite, and potassium permanganate and continue stirring for 20-30 min. Then raise the temperature to 50-55℃ and continue stirring for 5-7 h. After the reaction is complete, cool the reaction product to room temperature, then centrifuge. Wash the precipitate 2-3 times with distilled water, then place it in a vacuum drying oven and dry at 60-65℃ for 2-3 h to obtain doped expanded graphite. Step B2: Add anhydrous ethanol and deionized water to a three-necked flask equipped with a thermometer, stirrer, and constant pressure dropping funnel. Stir the reaction for 10-15 minutes at a temperature of 25-30℃ and a stirring rate of 300-400 r / min. Then adjust the pH to 9-10 with ammonia water. Add doped expanded graphite and continue stirring for 20-30 minutes. Then raise the temperature to 80-85℃ and add the modified solution dropwise while stirring, controlling the dropping rate to 1-2 drops / s. After the addition is complete, continue stirring for 1-1.5 hours. After the reaction is complete, cool the reaction product to room temperature and let it stand for 2-3 hours. Then filter under vacuum and place the filter cake in a vacuum drying oven at a temperature of 60-65℃ for 3-5 hours to obtain modified expanded graphite.

[0012] As a further aspect of the present invention: the ratio of deionized water, concentrated sulfuric acid, zinc borate, flake graphite and potassium permanganate used in step B1 is 10mL: 40-45mL: 1.2-1.8g: 5g: 0.7-1.1g.

[0013] As a further aspect of the present invention: the concentrated sulfuric acid in step B1 has a mass fraction of 98%.

[0014] As a further aspect of the present invention: the ratio of anhydrous ethanol, deionized water, doped expanded graphite and modified solution in step B2 is 40-50 mL: 40-50 mL: 10 g: 10-12 mL.

[0015] As a further aspect of the present invention: the mass fraction of the ammonia water in step B2 is 25-27%, and the modified solution is obtained by dissolving silane coupling agent KH-550 in anhydrous ethanol at a ratio of 0.25-1.55g:10mL.

[0016] As a further aspect of the present invention: the preparation method of the mining reinforcement material includes the following steps: Step 1: Add the modified isocyanate and dibutyltin dilaurate into a mixer and stir for 1-1.5 hours at a temperature of 25-30℃ and a stirring rate of 300-400 r / min to obtain component A; Step 2: Add polyether diol, waste gypsum, modified expanded graphite, cement and water into a mixer, and stir and react for 1-1.5 hours at a temperature of 25-30℃ and a stirring rate of 300-400 r / min to obtain component B; Step 3: Add component A and component B to the mixer at a mass ratio of 1:2-4, and stir for 5-9 hours at a temperature of 65-85℃ and a stirring rate of 300-400 r / min to obtain the mining reinforcement material.

[0017] The beneficial effects of this invention are: This invention discloses a mining reinforcement material, which is obtained by uniformly mixing modified isocyanate and dibutyltin dilaurate to obtain component A, and uniformly mixing polyether diol, waste gypsum, modified expanded graphite, cement, and water to obtain component B. Components A and B are then uniformly mixed to obtain the mining reinforcement material. This mining reinforcement material is an organic-inorganic composite mining reinforcement material. Utilizing the effective combination of a polyurethane matrix and an inorganic reinforcing phase, the mining reinforcement material exhibits good fluidity, facilitating rapid construction on-site. After construction, the cured mining reinforcement material maintains high toughness while exhibiting excellent strength, maintaining stable performance in harsh mining environments for extended periods. It also possesses good thermal conductivity and flame retardant properties, rapidly dissipating heat to prevent heat accumulation and effectively suppressing fire spread, thus meeting the needs of mine reinforcement.

[0018] In the preparation of this mine reinforcement material, a modified isocyanate was first prepared. This was achieved by reacting 4-nitro-3-trifluoromethylphenol with hexachlorocyclotriphosphazene. The hydroxyl group on 4-nitro-3-trifluoromethylphenol reacts with the chlorine atom on hexachlorocyclotriphosphazene, introducing a large amount of trifluoromethyl and nitro groups, yielding intermediate 1. Intermediate 1 then reacts with reduced iron powder, reducing the nitro group on intermediate 1 to an amino group, yielding intermediate 2. Intermediate 2 then reacts with 4,4'-diphenylmethane diisocyanate, where the amino group reacts with an isocyanate group on the 4,4'-diphenylmethane diisocyanate, simultaneously introducing a large number of isocyanate groups, resulting in the modified isocyanate. The molecular structure of this modified isocyanate is based on... Isocyanate monomers with cyclotriphosphazene as the backbone and polyisocyanate groups have more isocyanate groups, which increases the number of groups that can participate in the reaction per unit mass of the polyurethane formed, greatly improving the curing speed and the denser network structure of the cured polyurethane. This improves the mechanical strength of the mine reinforcement material. In addition, the cyclotriphosphazene backbone gives it the function of a phosphorus and nitrogen flame retardant, which greatly improves the flame retardant performance of the modified isocyanate and avoids the possibility of thermal runaway of polyurethane and fire. Using modified isocyanate as the polymer monomer can significantly improve the fluidity of the mine reinforcement material slurry, giving it good permeability and adsorption. It can effectively fill the cracks in the surrounding rock of the roadway, improve the integrity and strength of the surrounding rock, and facilitate the rapid reinforcement of the roadway. In the preparation of this mining reinforcement material, a modified expanded graphite was also prepared. First, zinc borate and flake graphite were used as raw materials. Zinc borate was intercalated into the flake graphite to obtain doped expanded graphite. Then, the doped expanded graphite was modified using a silane coupling agent KH-550. The siloxanes on the silane coupling agent KH-550 hydrolyzed to form silanols, which were then grafted onto the particle surface of the doped expanded graphite. Simultaneously, amino groups were introduced, resulting in modified expanded graphite. Expanded graphite expands when heated, absorbing a large amount of heat during the expansion process. This effectively reduces the surface temperature of the substrate, slowing down combustion and decomposition. Furthermore, the expanded carbon layer, forming a thermal insulation barrier, provides excellent anti-dripping, heat insulation, and mass barrier properties, reducing the diffusion of flammable gases generated during thermal degradation in both the gas and solid phases, preventing further flame spread and achieving flame retardant properties. The intercalated zinc borate absorbs heat... The amount of modified expanded graphite forms a viscous liquid with good fluidity, which encapsulates and covers the combustible substrate, forming a heat insulation layer. This significantly inhibits heat transfer and effectively prevents the continuous release of flammable gases, thus achieving flame retardant properties. Therefore, the synergistic effect of these two factors endows it with excellent flame retardant performance. Furthermore, modified expanded graphite has excellent thermal conductivity. When added to mining reinforcement materials, it can quickly dissipate the large amount of heat released during the curing of polyurethane materials, greatly improving their flame retardant performance and preventing heat accumulation and thermal runaway that could lead to fires. At the same time, modified expanded graphite has excellent mechanical properties, improving the integrity and strength of the surrounding rock in mining reinforcement materials. This can effectively improve the stability of the surrounding rock in roadways, reduce the occurrence of accidents such as roof falls and spalling, and ensure safe production in coal mines. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: This embodiment describes a method for preparing a mine reinforcement material, including the following steps: Step S1: 30 mmol of 4-nitro-3-trifluoromethylphenol, 5 mmol of hexachlorocyclotriphosphazene, 35 mmol of sodium hydroxide, 10 mL of deionized water and 60 mL of acetone were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 0 °C and 300 r / min for 1 h. The temperature was then raised to 25 °C and the mixture was stirred for 30 min. The temperature was then raised to reflux and the mixture was stirred for 4 h. After the reaction was completed, the reaction product was cooled to room temperature and then added to ice water. The mixture was then vacuum filtered and the filter cake was placed in a vacuum drying oven and dried at 50 °C for 2 h to obtain intermediate 1. Step S2: Add 3g of intermediate 1, 9g of reduced iron powder, 0.5g of 10% hydrochloric acid solution, 8mL of anhydrous ethanol, 8mL of anhydrous acetone, and 8mL of deionized water to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and reflux condenser. Purge with nitrogen for protection and stir at 25°C and 300r / min for 20min. Then, raise the temperature to reflux and continue stirring for 4h. After the reaction is complete, cool the reaction product to room temperature and then vacuum filter. Add the filtrate to ice water and adjust the pH to 7.5 with 20-25% sodium hydroxide solution. Let it stand to precipitate, then vacuum filter. Place the filter cake in a vacuum drying oven and dry at 50°C for 2h to obtain intermediate 2. Step S3: 10 mmol of intermediate 2, 60 mmol of 4,4'-diphenylmethane diisocyanate, 0.15 g of dibutyltin dilaurate and 100 mL of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 25 °C and 300 r / min for 15 min. Then the temperature was raised to 50 °C and the mixture was stirred for 3 h. After the reaction was completed, the reaction product was cooled to room temperature and then placed in a vacuum drying oven and dried at 60 °C for 3 h to obtain the modified isocyanate. Step S4: Add 10 mL of deionized water to a three-necked flask equipped with a thermometer, stirrer, and constant pressure dropping funnel. While stirring at 25 °C and a stirring rate of 300 r / min, add 40 mL of 98% concentrated sulfuric acid dropwise, controlling the dropping rate to 1 drop / s. After the addition is complete, continue stirring for 20 min. Then add 1.2 g of zinc borate, 5 g of flake graphite, and 0.7 g of potassium permanganate and continue stirring for 20 min. Then raise the temperature to 50 °C and continue stirring for 5 h. After the reaction is complete, cool the reaction product to room temperature, then centrifuge. Wash the precipitate twice with distilled water and then place it in a vacuum drying oven at 60 °C for 2 h to obtain doped expanded graphite. Step S5: Add 40 mL of anhydrous ethanol and 40 mL of deionized water to a three-necked flask equipped with a thermometer, stirrer, and constant pressure dropping funnel. Stir the reaction for 10 min at 25 °C and a stirring rate of 300 r / min. Then adjust the pH to 9 with ammonia water. Add 10 g of doped expanded graphite and continue stirring for 20 min. Then raise the temperature to 80 °C and add 10 mL of silane coupling agent KH-550 in a modified solution of 0.25 g: 10 mL dissolved in anhydrous ethanol dropwise while stirring. Control the dropping rate to 1 drop / s. After the addition is complete, continue stirring for 1 h. After the reaction is complete, cool the reaction product to room temperature and let it stand for 2 h. Then vacuum filter the product and place the filter cake in a vacuum drying oven and dry it at 60 °C for 3 h to obtain modified expanded graphite. Step S6: Weigh out 50 parts by weight of modified isocyanate, 0.25 parts by weight of dibutyltin dilaurate, 50 parts by weight of polyether diol, 24 parts by weight of waste gypsum, 10 parts by weight of modified expanded graphite, 7 parts by weight of cement, and 45 parts by weight for later use; the polyether diol is polyethylene glycol PEG1000; the waste gypsum has a particle size of 100 mesh and is phosphogypsum; the cement is silicate cement; Step S7: Add the modified isocyanate and dibutyltin dilaurate into a mixer and stir for 1 hour at a temperature of 25°C and a stirring rate of 300 r / min to obtain component A; Step S8: Add polyether diol, waste gypsum, modified expanded graphite, cement and water into a mixer, and stir and react for 1 hour at a temperature of 25°C and a stirring rate of 300 r / min to obtain component B. Step S9: Add component A and component B to the mixer at a mass ratio of 1:2, and stir for 5 hours at a temperature of 65℃ and a stirring rate of 300r / min to obtain the mining reinforcement material.

[0021] Example 2: This embodiment describes a method for preparing a mine reinforcement material, including the following steps: Step S1: 30 mmol of 4-nitro-3-trifluoromethylphenol, 5 mmol of hexachlorocyclotriphosphazene, 38 mmol of sodium hydroxide, 11 mL of deionized water and 62 mL of acetone were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 3°C ​​and 350 r / min for 1.2 h. The temperature was then raised to 28°C and the mixture was stirred for 35 min. The temperature was then raised to reflux and the mixture was stirred for 4.5 h. After the reaction was completed, the reaction product was cooled to room temperature and then added to ice water. The mixture was then vacuum filtered. The filter cake was placed in a vacuum drying oven and dried at 52°C for 2.5 h to obtain intermediate 1. Step S2: Add 3g of intermediate 1, 11g of reduced iron powder, 0.7g of 11% hydrochloric acid solution, 9mL of anhydrous ethanol, 9mL of anhydrous acetone, and 9mL of deionized water to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and reflux condenser. Purge with nitrogen for protection and stir at 28℃ and 350r / min for 25min. Then, heat to reflux and continue stirring for 4.5h. After the reaction is complete, cool the reaction product to room temperature and then vacuum filter. Add the filtrate to ice water and adjust the pH to 8 with 22% sodium hydroxide solution. Allow to stand to precipitate, then vacuum filter. Place the filter cake in a vacuum drying oven and dry at 52℃ for 2.5h to obtain intermediate 2. Step S3: 10 mmol of intermediate 2, 60 mmol of 4,4'-diphenylmethane diisocyanate, 0.2 g of dibutyltin dilaurate and 110 mL of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 28 °C and 350 r / min for 18 min. Then the temperature was raised to 52 °C and the mixture was stirred for 4 h. After the reaction was completed, the reaction product was cooled to room temperature and then placed in a vacuum drying oven and dried at 62 °C for 4 h to obtain the modified isocyanate. Step S4: Add 10 mL of deionized water to a three-necked flask equipped with a thermometer, stirrer, and constant pressure dropping funnel. While stirring at 28 °C and a stirring rate of 350 r / min, add 42 mL of 98% concentrated sulfuric acid dropwise, controlling the dropping rate to 1 drop / s. After the addition is complete, continue stirring for 25 min. Then add 1.5 g of zinc borate, 5 g of flake graphite, and 0.9 g of potassium permanganate and continue stirring for 25 min. Then raise the temperature to 52 °C and continue stirring for 6 h. After the reaction is complete, cool the reaction product to room temperature, then centrifuge. Wash the precipitate twice with distilled water and then place it in a vacuum drying oven at 62 °C for 2.5 h to obtain doped expanded graphite. Step S5: Add 45 mL of anhydrous ethanol and 45 mL of deionized water to a three-necked flask equipped with a thermometer, stirrer, and constant pressure dropping funnel. Stir the reaction at 28 °C and a stirring rate of 350 r / min for 12 min. Then adjust the pH to 9.5 with ammonia water. Add 10 g of doped expanded graphite and continue stirring for 25 min. Then raise the temperature to 82 °C and add 11 mL of silane coupling agent KH-550 in a modified solution of 0.9 g: 10 mL dissolved in anhydrous ethanol dropwise while stirring. Control the dropping rate to 1 drop / s. After the addition is complete, continue stirring for 1.2 h. After the reaction is complete, cool the reaction product to room temperature and let it stand for 2.5 h. Then vacuum filter the product and place the filter cake in a vacuum drying oven and dry it at 62 °C for 4 h to obtain modified expanded graphite. Step S6: Weigh out 60 parts by weight of modified isocyanate, 0.45 parts by weight of dibutyltin dilaurate, 55 parts by weight of polyether diol, 30 parts by weight of waste gypsum, 14 parts by weight of modified expanded graphite, 11 parts by weight of cement, and 55 parts by weight for later use; the polyether diol is polyethylene glycol PEG1000; the waste gypsum has a particle size of 200 mesh and is desulfurized gypsum; the cement is silicate cement; Step S7: Add the modified isocyanate and dibutyltin dilaurate into a mixer and stir for 1.2 h at a temperature of 28℃ and a stirring rate of 350 r / min to obtain component A; Step S8: Add polyether diol, waste gypsum, modified expanded graphite, cement and water to a mixer and stir for 1.2 h at a temperature of 28℃ and a stirring rate of 350 r / min to obtain component B; Step S9: Add component A and component B to the mixer at a mass ratio of 1:3, and stir for 7 hours at a temperature of 75℃ and a stirring rate of 350r / min to obtain the mining reinforcement material.

[0022] Example 3: This embodiment describes a method for preparing a mine reinforcement material, including the following steps: Step S1: 30 mmol of 4-nitro-3-trifluoromethylphenol, 5 mmol of hexachlorocyclotriphosphazene, 40 mmol of sodium hydroxide, 12 mL of deionized water and 65 mL of acetone were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 5 °C and 400 r / min for 1.5 h. The temperature was then raised to 30 °C and the mixture was stirred for 40 min. The temperature was then raised to reflux and the mixture was stirred for 5 h. After the reaction was completed, the reaction product was cooled to room temperature and then added to ice water. The mixture was then vacuum filtered and the filter cake was placed in a vacuum drying oven and dried at 55 °C for 3 h to obtain intermediate 1. Step S2: Add 3g of intermediate 1, 13g of reduced iron powder, 0.9g of 12% hydrochloric acid solution, 10mL of anhydrous ethanol, 10mL of anhydrous acetone, and 10mL of deionized water to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and reflux condenser. Purge with nitrogen for protection and stir at 30℃ and 400r / min for 30min. Then, heat to reflux and continue stirring for 5h. After the reaction is complete, cool the reaction product to room temperature and then vacuum filter. Add the filtrate to ice water and adjust the pH to 8.5 with 25% sodium hydroxide solution. Allow to stand to precipitate, then vacuum filter. Place the filter cake in a vacuum drying oven and dry at 55℃ for 3h to obtain intermediate 2. Step S3: 10 mmol of intermediate 2, 60 mmol of 4,4'-diphenylmethane diisocyanate, 0.25 g of dibutyltin dilaurate and 120 mL of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 30 °C and 400 r / min for 20 min. Then the temperature was raised to 55 °C and the mixture was stirred for 5 h. After the reaction was completed, the reaction product was cooled to room temperature and then placed in a vacuum drying oven and dried at 65 °C for 5 h to obtain the modified isocyanate. Step S4: Add 10 mL of deionized water to a three-necked flask equipped with a thermometer, stirrer, and constant pressure dropping funnel. While stirring at 30 °C and a stirring rate of 400 r / min, add 45 mL of 98% concentrated sulfuric acid dropwise, controlling the dropping rate to 2 drops / s. After the addition is complete, continue stirring for 30 min. Then add 1.8 g of zinc borate, 5 g of flake graphite, and 1.1 g of potassium permanganate and continue stirring for 30 min. Then raise the temperature to 55 °C and continue stirring for 7 h. After the reaction is complete, cool the reaction product to room temperature, then centrifuge. Wash the precipitate three times with distilled water, then place it in a vacuum drying oven and dry at 65 °C for 3 h to obtain doped expanded graphite. Step S5: Add 50 mL of anhydrous ethanol and 50 mL of deionized water to a three-necked flask equipped with a thermometer, stirrer, and constant pressure dropping funnel. Stir the reaction at 30 °C and a stirring rate of 400 r / min for 15 min. Then adjust the pH to 10 with ammonia water. Add 10 g of doped expanded graphite and continue stirring for 30 min. Then raise the temperature to 85 °C and add 12 mL of silane coupling agent KH-550 in a modified solution of 1.55 g: 10 mL dissolved in anhydrous ethanol dropwise while stirring. Control the dropping rate to 2 drops / s. After the addition is complete, continue stirring for 1.5 h. After the reaction is complete, cool the reaction product to room temperature and let it stand for 3 h. Then vacuum filter the product and place the filter cake in a vacuum drying oven and dry it at 65 °C for 5 h to obtain modified expanded graphite. Step S6: Weigh out 70 parts by weight of modified isocyanate, 0.65 parts by weight of dibutyltin dilaurate, 60 parts by weight of polyether diol, 36 parts by weight of waste gypsum, 18 parts by weight of modified expanded graphite, 15 parts by weight of cement, and 65 parts by weight for later use; the polyether diol is polypropylene glycol PPG1000; the waste gypsum has a particle size of 300 mesh and is fluorogypsum; the cement is silicate cement; Step S7: Add the modified isocyanate and dibutyltin dilaurate into a mixer and stir for 1.5 h at a temperature of 30℃ and a stirring rate of 400 r / min to obtain component A; Step S8: Add polyether diol, waste gypsum, modified expanded graphite, cement and water into a mixer, and stir and react for 1.5 h at a temperature of 30℃ and a stirring rate of 400 r / min to obtain component B; Step S9: Add component A and component B to the mixer at a mass ratio of 1:4, and stir for 9 hours at a temperature of 85℃ and a stirring rate of 400r / min to obtain the mining reinforcement material.

[0023] Comparative Example 1: This comparative example illustrates a method for preparing a mine reinforcement material, comprising the following steps: Step S1: Weigh out 70 parts by weight of 4,4'-diphenylmethane diisocyanate, 0.65 parts by weight of dibutyltin dilaurate, 60 parts by weight of polyether diol, 36 parts by weight of waste gypsum, 15 parts by weight of cement, and 65 parts by weight for later use; the polyether diol is polypropylene glycol PPG1000; the waste gypsum has a particle size of 300 mesh and is fluorogypsum; the cement is silicate cement; Step S2: Add 4,4'-diphenylmethane diisocyanate and dibutyltin dilaurate to a mixer and stir for 1.5 h at a temperature of 30°C and a stirring rate of 400 r / min to obtain component A; Step S3: Add polyether diol, waste gypsum, cement and water to a mixer and stir for 1.5 h at a temperature of 30℃ and a stirring rate of 400 r / min to obtain component B; Step S4: Add component A and component B to the mixer at a mass ratio of 1:4, and stir for 9 hours at a temperature of 85℃ and a stirring rate of 400r / min to obtain the mining reinforcement material.

[0024] Comparative Example 2: This comparative example illustrates a method for preparing a mine reinforcement material, comprising the following steps: Step S1: 30 mmol of 4-nitro-3-trifluoromethylphenol, 5 mmol of hexachlorocyclotriphosphazene, 40 mmol of sodium hydroxide, 12 mL of deionized water and 65 mL of acetone were added to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube and reflux condenser. Nitrogen gas was introduced for protection. The mixture was stirred at 5 °C and 400 r / min for 1.5 h. The temperature was then raised to 30 °C and the mixture was stirred for 40 min. The temperature was then raised to reflux and the mixture was stirred for 5 h. After the reaction was completed, the reaction product was cooled to room temperature and then added to ice water. The mixture was then vacuum filtered and the filter cake was placed in a vacuum drying oven and dried at 55 °C for 3 h to obtain intermediate 1. Step S2: Add 3g of intermediate 1, 13g of reduced iron powder, 0.9g of 12% hydrochloric acid solution, 10mL of anhydrous ethanol, 10mL of anhydrous acetone, and 10mL of deionized water to a three-necked flask equipped with a stirrer, thermometer, gas delivery tube, and reflux condenser. Purge with nitrogen for protection and stir at 30℃ and 400r / min for 30min. Then, heat to reflux and continue stirring for 5h. After the reaction is complete, cool the reaction product to room temperature and then vacuum filter. Add the filtrate to ice water and adjust the pH to 8.5 with 25% sodium hydroxide solution. Allow to stand to precipitate, then vacuum filter. Place the filter cake in a vacuum drying oven and dry at 55℃ for 3h to obtain intermediate 2. Step S3: 10 mmol of intermediate 2, 60 mmol of 4,4'-diphenylmethane diisocyanate, 0.25 g of dibutyltin dilaurate and 120 mL of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, thermometer and gas delivery tube. Nitrogen gas was introduced for protection. The mixture was stirred at 30 °C and 400 r / min for 20 min. Then the temperature was raised to 55 °C and the mixture was stirred for 5 h. After the reaction was completed, the reaction product was cooled to room temperature and then placed in a vacuum drying oven and dried at 65 °C for 5 h to obtain the modified isocyanate. Step S4: Weigh out 70 parts by weight of modified isocyanate, 0.65 parts by weight of dibutyltin dilaurate, 60 parts by weight of polyether diol, 36 parts by weight of waste gypsum, 15 parts by weight of cement, and 65 parts by weight for later use; the polyether diol is polypropylene glycol PPG1000; the waste gypsum has a particle size of 300 mesh and is fluorogypsum; the cement is silicate cement; Step S5: Add the modified isocyanate and dibutyltin dilaurate into a mixer and stir for 1.5 h at a temperature of 30℃ and a stirring rate of 400 r / min to obtain component A; Step S6: Add polyether diol, waste gypsum, cement and water to a mixer and stir for 1.5 h at a temperature of 30℃ and a stirring rate of 400 r / min to obtain component B; Step S7: Add component A and component B to the mixer at a mass ratio of 1:4, and stir for 9 hours at a temperature of 85℃ and a stirring rate of 400r / min to obtain the mining reinforcement material.

[0025] Comparative Example 3: This comparative example illustrates a method for preparing a mine reinforcement material, comprising the following steps: Step S1: Add 10 mL of deionized water to a three-necked flask equipped with a thermometer, stirrer, and constant pressure dropping funnel. While stirring at 30 °C and a stirring rate of 400 r / min, add 45 mL of 98% concentrated sulfuric acid dropwise, controlling the dropping rate to 2 drops / s. After the addition is complete, continue stirring for 30 min. Then add 1.8 g of zinc borate, 5 g of flake graphite, and 1.1 g of potassium permanganate and continue stirring for 30 min. Then raise the temperature to 55 °C and continue stirring for 7 h. After the reaction is complete, cool the reaction product to room temperature, then centrifuge. Wash the precipitate three times with distilled water, then place it in a vacuum drying oven and dry at 65 °C for 3 h to obtain doped expanded graphite. Step S2: Add 50 mL of anhydrous ethanol and 50 mL of deionized water to a three-necked flask equipped with a thermometer, stirrer, and constant pressure dropping funnel. Stir the reaction at 30 °C and a stirring rate of 400 r / min for 15 min. Then adjust the pH to 10 with ammonia water. Add 10 g of doped expanded graphite and continue stirring for 30 min. Then raise the temperature to 85 °C and add 12 mL of silane coupling agent KH-550 in a modified solution of 1.55 g: 10 mL dissolved in anhydrous ethanol dropwise while stirring. Control the dropping rate to 2 drops / s. After the addition is complete, continue stirring for 1.5 h. After the reaction is complete, cool the reaction product to room temperature and let it stand for 3 h. Then vacuum filter the product and place the filter cake in a vacuum drying oven and dry it at 65 °C for 5 h to obtain modified expanded graphite. Step S3: Weigh out 70 parts by weight of 4,4'-diphenylmethane diisocyanate, 0.65 parts by weight of dibutyltin dilaurate, 60 parts by weight of polyether diol, 36 parts by weight of waste gypsum, 18 parts by weight of modified expanded graphite, 15 parts by weight of cement, and 65 parts by weight for later use; the polyether diol is polypropylene glycol PPG1000; the waste gypsum has a particle size of 300 mesh and is fluorogypsum; the cement is silicate cement; Step S4: Add 4,4'-diphenylmethane diisocyanate and dibutyltin dilaurate to a mixer and stir for 1.5 h at a temperature of 30°C and a stirring rate of 400 r / min to obtain component A; Step S5: Add polyether diol, waste gypsum, modified expanded graphite, cement and water into a mixer, and stir and react for 1.5 h at a temperature of 30℃ and a stirring rate of 400 r / min to obtain component B; Step S6: Add component A and component B to the mixer at a mass ratio of 1:4, and stir for 9 hours at a temperature of 85℃ and a stirring rate of 400r / min to obtain the mining reinforcement material.

[0026] The performance of the mining reinforcement materials of Examples 1-3 and Comparative Examples 1-3 was tested, and the test results are shown in the table below: Referring to the data in the table above, and based on the comparison between Examples 1-3 and Comparative Examples 1-3, it can be seen that adding modified isocyanate and modified expanded graphite can effectively improve the mechanical properties and flame retardant properties of mining reinforcement materials, and the performance improvement effect of mining reinforcement materials is most significant under the synergistic effect of modified isocyanate and modified expanded graphite.

[0027] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0028] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A mine reinforcing material, characterised in that, The A component and the B component are included; The mass ratio of the A component and the B component is 1:2-4; The A component includes the following components by weight: modified isocyanate 50-70 parts, dibutyltin dilaurate 0.25-0.65 parts; The B component includes the following components by weight: polyether diol 50-60 parts, waste gypsum 24-36 parts, modified expanded graphite 10-18 parts, cement 7-15 parts, and water 45-65 parts; the polyether diol is one of polyethylene glycol PEG1000 and polypropylene glycol PPG1000; the waste gypsum has a particle size of 100-300 meshes, and is one of phosphogypsum, desulfurization gypsum, and fluorogypsum; the cement is Portland cement; The modified isocyanate is prepared by the following steps: Step A1: 4-nitro-3-trifluoromethyl phenol, hexachlorocyclotriphosphazene, sodium hydroxide, deionized water, and acetone are stirred to react, the reaction product is cooled after the reaction is completed, then added to ice water, vacuum filtration, and the filter cake is dried to obtain intermediate 1; Step A2: intermediate 1, reduced iron powder, hydrochloric acid solution, anhydrous ethanol, anhydrous acetone, and deionized water are stirred to react, the reaction product is cooled after the reaction is completed, then added to ice water, the pH is adjusted with a sodium hydroxide solution, and the precipitate is separated by standing, vacuum filtration, and the filter cake is dried to obtain intermediate 2; Step A3: intermediate 2, 4, 4'-diphenyl methane diisocyanate, dibutyltin dilaurate, and N, N-dimethylformamide are stirred to react, the reaction product is cooled after the reaction is completed, and then dried to obtain the modified isocyanate.

2. A mine reinforcing material according to claim 1, characterised in that The amount ratio of 4-nitro-3-trifluoromethyl phenol, hexachlorocyclotriphosphazene, sodium hydroxide, deionized water, and acetone in step A1 is 30 mmol:5 mmol:35-40 mmol:10-12 mL:60-65 mL.

3. The mine reinforcing material of claim 1, wherein The amount ratio of intermediate 1, reduced iron powder, hydrochloric acid solution, anhydrous ethanol, anhydrous acetone, and deionized water in step A2 is 3 g:9-13 g:0.5-0.9 g:8-10 mL:8-10 mL:8-10 mL.

4. The mine reinforcing material of claim 1, wherein The mass fraction of the hydrochloric acid solution in step A2 is 10-12%, and the mass fraction of the sodium hydroxide solution is 20-25%.

5. The mine reinforcing material of claim 1, wherein The amount ratio of intermediate 2, 4, 4'-diphenyl methane diisocyanate, dibutyltin dilaurate, and N, N-dimethylformamide in step A3 is 10 mmol:60 mmol:0.15-0.25 g:100-120 mL.

6. The mine reinforcing material of claim 1, wherein The modified expanded graphite is prepared by the following steps: Step B1: concentrated sulfuric acid is added dropwise to deionized water while stirring, then zinc borate, flake graphite, and potassium permanganate are added and continue to stir to react, the reaction product is cooled after the reaction is completed, then centrifuged, and the precipitate is washed and dried to obtain doped expanded graphite; Step B2: stirring reaction of anhydrous ethanol and deionized water, then adjusting pH with ammonia water, then adding doped expanded graphite and continuing stirring reaction, then adding modified solution drop by drop while stirring, continuing stirring reaction after dropwise addition, cooling reaction product after reaction, then standing and aging, vacuum filtration, drying filter cake, and obtaining modified expanded graphite.

7. A mine reinforcing material according to claim 6, characterised in that The amount ratio of the deionized water, concentrated sulfuric acid, zinc borate, flake graphite and potassium permanganate in step B1 is 10mL:40-45mL:1.2-1.8g:5g:0.7-1.1g; the mass fraction of the concentrated sulfuric acid is 98%.

8. A mine reinforcing material according to claim 6, characterised in that The amount ratio of the anhydrous ethanol, deionized water, doped expanded graphite and modified solution in step B2 is 40-50mL:40-50mL:10g:10-12mL.

9. The mine reinforcing material of claim 6, wherein, The mass fraction of the ammonia water in step B2 is 25-27%, and the modified solution is obtained by dissolving silane coupling agent KH-550 in anhydrous ethanol according to 0.25-1.55g:10mL.

10. The mine reinforcing material of claim 1, wherein, The preparation method of the mine reinforcing material comprises the following steps: Step one: adding modified isocyanate and dibutyltin dilaurate into a mixer, stirring reaction at a temperature of 25-30℃ and a stirring rate of 300-400r / min for 1-1.5h to obtain component A; Step two: adding polyether diol, waste gypsum, modified expanded graphite, cement and water into a mixer, stirring reaction at a temperature of 25-30℃ and a stirring rate of 300-400r / min for 1-1.5h to obtain component B; Step three: adding component A and component B into a mixer according to a mass ratio of 1:2-4, stirring reaction at a temperature of 65-85℃ and a stirring rate of 300-400r / min for 5-9h to obtain the mine reinforcing material.

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