Polyurethane material for coal rock mass and preparation method thereof

Abstract

The invention belongs to the technical field of polyurethane, and particularly relates to a polyurethane material for coal rock mass and a preparation method of the polyurethane material. The polyurethane material for the coal rock mass is composed of a white material and a black material according to the mass ratio of 1: 1, and the white material comprises the following raw materials: mining polyether polyol, a flame retardant and a catalyst; the black material comprises the following raw materials: a prepolymer and a flame retardant. According to the polyurethane material for the coal and rock mass, hexahydroxy triphenylene with a star-shaped molecular structure is introduced into mine polyether polyol synthesis, a highly-crosslinked star-shaped structure is formed, rigidity and flexibility are balanced, and meanwhile the crosslinking density and compressive strength of a product are improved; secondly, bisphenol A with a benzene ring structure is adopted as a raw material for synthesizing the prepolymer, the toughness and strength of the material are improved through the interaction of benzene rings, and the prepared polyurethane material is high in compressive strength and low in reaction heat and meets the requirements of the polyurethane material for coal rock mass; the invention further provides a preparation method, and the preparation process is simple.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyurethanes, and particularly relates to a polyurethane material for coal and rock masses and a preparation method thereof. Background Art

[0002] In the fields of mine exploitation and underground engineering construction, polyurethane materials have become indispensable engineering materials due to their excellent physical and chemical properties. Mine-used polyether polyols, as the core raw materials of polyurethane materials, play a key role in the mine-used reinforcement material system. Taking grouting materials as an example, they can effectively improve the stability of roadways by filling fissures and reinforcing surrounding rocks; spray support materials can quickly form a dense protective layer to resist groundwater erosion and surrounding rock deformation, and are widely used in scenarios such as coal mine roadway maintenance and tunnel anti-seepage reinforcement. The design concept of traditional mine-used polyether polyols focuses on high reactivity to meet the urgent need for rapid curing at the engineering site. Although this design strategy can achieve the instant molding of materials, its violent exothermic reaction characteristics bring multiple technical bottlenecks. From a safety perspective, the local temperature rises sharply during the construction process, easily reaching the ignition point of combustible substances and triggering major safety accidents such as gas explosions or dust combustion; at the material performance level, the non-uniform heat conduction during the curing process leads to the accumulation of internal thermal stress, resulting in defects such as cracks and deformations in the material, significantly reducing the mechanical properties such as impact resistance and tensile resistance of the final product; in addition, the too-fast curing speed greatly compresses the construction operation window, making it difficult to achieve precise spraying or uniform grouting under working conditions with complex geological structures and limited construction spaces, seriously restricting the construction efficiency and engineering quality.

[0003] CN119306910A discloses a mine-used reinforcement material with low reaction heat and a preparation method thereof. By mixing bisphenol-based polyether polyol A with a specific initiator and high-functional polyether polyol B, the reaction heat is reduced while ensuring the strength of the reinforcement material; at the same time, polyether polyol C initiated with tetrabromobisphenol A enhances the flame retardancy, toughness and strength of the prepolymer. The prepared reinforcement material has high compressive strength and low reaction heat, meeting the mine-used requirements and improving construction safety. However, two polyethers need to be added to the white material and a viscosity reducer needs to be added to the black material to reduce the viscosity of the system, resulting in high requirements for mixing uniformity and strong dependence on equipment, making the construction process complex during underground application. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a polyurethane material for coal and rock masses. By introducing hexahydroxy triphenylene with a star molecular structure in the synthesis of mine polyether polyol, a highly cross-linked star structure is formed, which balances rigidity and flexibility while improving the cross-linking density and compressive strength of the product. Secondly, bisphenol A containing a benzene ring structure is used as a raw material for synthesizing the prepolymer. Through the interaction of benzene rings, the toughness and strength of the material are improved. The prepared polyurethane material has high compressive strength and low reaction heat, meeting the requirements of polyurethane materials for coal and rock masses. The present invention also provides a preparation method thereof, and the preparation process is simple.

[0005] The polyurethane material for coal and rock masses described in the present invention is composed of white material and black material in a mass ratio of 1:1. Among them, the white material includes the following raw materials in parts by mass: 75 - 80 parts of mine polyether polyol, 20 - 25 parts of flame retardant, and 0.5 - 0.6 part of catalyst; the black material includes the following raw materials in parts by mass: 75 - 80 parts of prepolymer and 20 - 25 parts of flame retardant.

[0006] The mine polyether polyol is prepared by reacting hexahydroxy triphenylene and polyol as mixed initiators with alkylene oxide under the action of an alkaline catalyst.

[0007] The prepolymer is obtained by mixing and reacting polymeric MDI and bisphenol A in a mass ratio of 100:(8 - 14) at 60 - 70 °C. Polymeric MDI is preferably PM - 200, purchased from Wanhua Chemical Group Co., Ltd.

[0008] The specific preparation process of the mine polyether polyol is as follows: (1) Dissolve hexahydroxy triphenylene in the solvent N,N - dimethylformamide, add triethylamine to adjust the pH of the solution to 9 - 11, then add polyol, add an alkaline catalyst, replace with nitrogen and then raise the temperature under vacuum, keep the temperature at 80 - 85 °C and the pressure at 0.1 - 0.4 MPa, dropwise add alkylene oxide, and continue to react for 1 - 2 h after the feeding is completed to obtain an intermediate polyether polyol. Among them, after hexahydroxy triphenylene and the solvent N,N - dimethylformamide are dissolved to form a homogeneous solution, the concentration of hexahydroxy triphenylene in the solution is 20 - 30 wt.%. (2) Raise the temperature of the intermediate polyether polyol to 100 - 110 °C, keep the pressure at 0.1 - 0.4 MPa, dropwise add alkylene oxide again, supplement the pressure to 0.2 - 0.3 MPa after the feeding is completed, and keep the pressure and react for 2 - 3 h to obtain a polyether polyol crude product. (3) Keep the polyether polyol crude product at 155 - 160 °C, bubble with nitrogen for 1 - 2 h and then discharge the material to obtain the mine polyether polyol.

[0009] The hexahydroxy triphenylene accounts for 35 - 50 wt.% of the total amount of the mixed initiators, and the total amount of the mixed initiators is the sum of the dosages of hexahydroxy triphenylene and polyol.

[0010] The polyol is a variety of sucrose, solid sorbitol, diethylene glycol, glycerol, ethylene glycol, propylene glycol, etc.

[0011] The basic catalyst is one or more of dimethylamine, 2,4,6 - tris(dimethylaminomethyl)phenol, N,N - dimethylbenzylamine, and the addition amount of the basic catalyst is 0.8 - 1.0 wt.% of the total amount of the mixed initiators and the total amount of the alkylene oxide.

[0012] In the step (1), the alkylene oxide is ethylene oxide, in the step (2), the alkylene oxide is propylene oxide, and the dosage of ethylene oxide in the step (1) accounts for 20 - 40 wt.% of the total amount of the alkylene oxide.

[0013] The mass ratio of the total amount of the mixed initiators to the total amount of the alkylene oxide is 1:(2.90 - 3.65).

[0014] The flame retardant in the white material and the black material is one of tris(1 - chloro - 2 - propyl) phosphate (TCPP), tris(2 - chloroethyl) phosphate (TCEP), and triethyl phosphate (TEP).

[0015] The catalyst in the white material is one of bismuth neodecanoate and bismuth laurate.

[0016] The preparation method of the polyurethane material for coal and rock mass includes the following steps: the white material and the black material are first mixed separately, and then the white material and the black material are stirred in a high - speed mixer according to the mass ratio and then injected into a mold for curing and forming to obtain the polyurethane material for coal and rock mass.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In the present invention, by introducing hexahydroxy triphenylene into the synthesis of the mine - used polyether polyol, its unique star - shaped molecular structure, each hydroxyl group can independently initiate a polyether chain. By adjusting the dosage of the alkylene oxide and controlling the branch chain length, a highly cross - linked star - shaped structure is formed, which improves the cross - link density and compressive strength while balancing rigidity and flexibility, thereby endowing the product with higher compressive strength and lower reaction heat.

[0018] (2) The present invention uses hexahydroxy triphenylene and polyol as the mixed initiators to prepare the mine - used polyether polyol. The core of hexahydroxy triphenylene is a rigid planar structure formed by the fusion of three benzene rings. The rigid polycyclic structure is embedded in the main chain or side chain of the polyether polyol as a "cross - link node", further restricting the mobility of the molecular chain, reducing the relaxation or slip of the chain segments at high temperatures, thereby inhibiting thermal degradation and ensuring that the product has excellent thermal stability.

[0019] (3) The prepolymer in the black material of the present invention uses bisphenol A with a benzene ring structure as the raw material for synthesizing the prepolymer. Through the interaction of benzene rings, the toughness and strength of the material are improved, meeting the strict requirements of the product for strength and low reaction heat.

[0020] (4) The polyurethane material for coal and rock mass of the present invention has a simple preparation process. The reaction heat of the prepared polyurethane material for coal and rock mass is below 90.1 °C, and the compressive strength can reach above 68.9 MPa. Specific Embodiments

[0021] The present invention will be further described below in conjunction with examples and comparative examples.

[0022] Unless otherwise specified, the raw materials used in the examples and comparative examples are all conventional commercially available raw materials, and the processes used in the examples and comparative examples are all conventional methods in the art unless otherwise specified.

[0023] The specific preparation process of the described polyether polyol for mining is as follows: (1) In a 3.5 L autoclave equipped with a stirrer, a meter, a heating temperature control device, a cooling device (including an outer jacket and an inner coil), and a pressure sensor, hexahydroxy triphenylene is dissolved in the solvent N,N-dimethylformamide. Triethylamine is added to adjust the pH of the solution to 9 - 11. Subsequently, polyol and a basic catalyst are added. Nitrogen is filled into the reaction kettle for leak detection. Under the condition of ensuring good sealing of the reaction kettle, nitrogen replacement is carried out. After nitrogen replacement, the temperature is raised to 82.5 ± 2.5 °C, and the pressure is 0.25 ± 0.15 MPa. Ethylene oxide is added dropwise. After the feeding is completed, the pressure is maintained for reaction for 1 - 2 h to obtain an intermediate polyether polyol; (2) The temperature in the autoclave is raised to 105 ± 5 °C, and the pressure is maintained at 0.25 ± 0.15 MPa. Propylene oxide is added dropwise. After the feeding is completed, the pressure is supplemented to 0.2 - 0.3 MPa, and the pressure is maintained for reaction for 2 - 3 h to obtain a polyether polyol crude product; (3) When the pressure no longer decreases, the polyether polyol crude product is kept at 155 - 160 °C, nitrogen is bubbled for 1 - 2 h, and then the material is discharged and filtered to obtain the polyether polyol for mining.

[0024] The preparation method of the described polyurethane material for coal and rock mass includes the following steps: The white material comprises raw materials in the following parts by mass: 75 - 80 parts of mine - used polyether polyol, 20 - 25 parts of flame retardant, 0.5 - 0.6 part of catalyst; the black material comprises raw materials in the following parts by mass: 75 - 80 parts of prepolymer, 20 - 25 parts of flame retardant; wherein, the prepolymer is obtained by mixing PM - 200 and bisphenol A in a mass ratio of 100:(8 - 14) at 60 - 70 °C and reacting; the above - mentioned white material and black material are first mixed separately, then the white material and black material are stirred in a high - speed mixer according to a mass ratio of 1:1, and then injected into a mold and cured to form a polyurethane material for coal and rock mass.

[0025] Example 1 The specific preparation process of the mine - used polyether polyol is as follows: (1) Add 100 g of hexahydroxy triphenylene and 400 g of N,N - dimethylformamide into a 3.5 L high - pressure autoclave equipped with a stirrer, a meter, a heating temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor. Use triethylamine to adjust the pH of the solution to 9, keep it warm at 80 °C and stir for 2 h, then add 40 g of sucrose, 90 g of diethylene glycol, 50 g of glycerol, and 4 g of N,N - dimethylbenzylamine. Fill the reaction kettle with nitrogen for leak detection. Under the condition of ensuring good sealing of the reaction kettle, carry out nitrogen replacement. After the nitrogen replacement is completed, vacuum - pump 5.08 g of dimethylamine, then raise the temperature to 82.5 ± 2.5 °C, keep the pressure at 0.25 ± 0.15 MPa, and drop - add 171 g of ethylene oxide. After the feeding is completed, continue to keep the pressure and react for 1 h to obtain an intermediate polyether polyol; (2) Raise the temperature in the high - pressure autoclave to 105 ± 5 °C, keep the pressure at 0.25 ± 0.15 MPa, drop - add 648 g of propylene oxide. After the feeding is completed, supplement the pressure to 0.25 MPa and keep the pressure and react for 2.5 h to obtain a polyether polyol crude product; (3) When the pressure no longer decreases, keep the polyether polyol crude product warm at 155 °C, bubble with nitrogen for 1.5 h and then discharge the material, and filter to obtain the mine - used polyether polyol.

[0026] The preparation method of the polyurethane material for coal and rock mass includes the following steps: The white material comprises raw materials in the following parts by mass: 75 parts of mine - used polyether polyol, 25 parts of TCPP, 0.5 part of bismuth neodecanoate; the black material comprises raw materials in the following parts by mass: 75 parts of prepolymer, 25 parts of TCPP; wherein, the prepolymer is prepared by reacting PM - 200 and bisphenol A in a mass ratio of 100:8 at 60 °C for 2 h; the above - mentioned white material and black material are first mixed separately, then the white material and black material are stirred in a high - speed mixer according to a mass ratio of 1:1, and then injected into a mold. After curing at room temperature for 12 min, open the mold to obtain the polyurethane material for coal and rock mass.

[0027] Example 2 The specific preparation process of the polyether polyol for mining is as follows: (1) Add 130 g of hexahydroxy triphenylene and 390 g of N,N-dimethylformamide into a 3.5 L autoclave equipped with a stirrer, a meter, a heating temperature control device, a cooling device (including an outer jacket and an inner coil), and a pressure sensor. Use triethylamine to adjust the pH of the solution to 10, keep it warm at 80 °C and stir for 2 h, then add 50 g of solid sorbitol, 60 g of ethylene glycol, 60 g of propylene glycol, and 12.5 g of 2,4,6-tris(dimethylaminomethyl)phenol. Fill the reaction kettle with nitrogen for leak detection. Under the condition of ensuring good sealing of the reaction kettle, conduct nitrogen replacement on it. After nitrogen replacement, raise the temperature to 82.5 ± 2.5 °C, keep the pressure at 0.25 ± 0.15 MPa, and dropwise add 324 g of ethylene oxide. After the feeding is completed, continue the pressure-holding reaction for 3 h to obtain an intermediate polyether polyol; (2) Raise the temperature in the autoclave to 105 ± 5 °C, keep the pressure at 0.25 ± 0.15 MPa, and dropwise add 757 g of propylene oxide. After the feeding is completed, supplement the pressure to 0.2 MPa and conduct a pressure-holding reaction for 3 h to obtain a polyether polyol crude product; (3) When the pressure no longer decreases, keep the polyether polyol crude product warm at 157.5 °C, conduct nitrogen bubbling for 2 h, then discharge the material and filter it to obtain the polyether polyol for mining.

[0028] The preparation method of the polyurethane material for coal and rock mass includes the following steps: The white material includes raw materials in the following mass fractions: 77.5 parts of polyether polyol for mining, 22.5 parts of TCEP, and 0.55 part of bismuth laurate; the black material includes raw materials in the following mass fractions: 77.5 parts of prepolymer, 22.5 parts of TCEP; among them, the prepolymer is prepared by reacting PM-200 and bisphenol A in a mass ratio of 100:11 at 65 °C for 2.5 h. First, mix the above white material and black material respectively, then mix the white material and black material in a mass ratio of 1:1 in a high-speed mixer, and then inject them into a mold. After curing at room temperature for 12 min, open the mold to obtain the polyurethane material for coal and rock mass.

[0029] Example 3 The specific preparation process of the polyether polyol for mining is as follows: (1) Add 130 g of hexahydroxy triphenylene and 303 g of N,N-dimethylformamide into a 3.5 L autoclave equipped with a stirrer, a meter, a heating temperature control device, a cooling device (including an outer jacket and an inner coil), and a pressure sensor. Use triethylamine to adjust the pH of the solution to 11. Keep the temperature at 80 °C and stir for 2 h, then add 50 g of solid sorbitol, 60 g of ethylene glycol, 20 g of glycerol, and 6.1 g of 2,4,6-tris(dimethylaminomethyl)phenol. Fill the autoclave with nitrogen for leak testing. Under the condition of ensuring good sealing of the autoclave, carry out nitrogen replacement. After the nitrogen replacement is completed, vacuum pump 6 g of dimethylamine into it. Then raise the temperature to 82.5 ± 2.5 °C, keep the pressure at 0.25 ± 0.15 MPa, and dropwise add 380 g of ethylene oxide. After the feeding is completed, continue the pressure-holding reaction for 1.5 h to obtain the intermediate polyether polyol; (2) Raise the temperature in the autoclave to 105 ± 5 °C, keep the pressure at 0.25 ± 0.15 MPa, and dropwise add 570 g of propylene oxide. After the feeding is completed, supplement the pressure to 0.3 MPa and carry out the pressure-holding reaction for 2 h to obtain the crude polyether polyol; (3) When the pressure no longer decreases, keep the crude polyether polyol at 160 °C, bubble nitrogen for 1 h, then discharge the material and filter to obtain the polyether polyol for coal and rock mass.

[0030] The preparation method of the polyurethane material for coal and rock mass includes the following steps: The white material includes the following raw materials in parts by mass: 80 parts of polyether polyol for coal and rock mass, 20 parts of TEP, and 0.6 part of bismuth neodecanoate; the black material includes the following raw materials in parts by mass: 80 parts of prepolymer and 20 parts of TEP; among them, the prepolymer is prepared by reacting PM-200 and bisphenol A in a mass ratio of 100:14 at 70 °C for 3 h. First, mix the above white material and black material separately, then mix the white material and black material in a mass ratio of 1:1 in a high-speed mixer, and then inject them into a mold. After curing at room temperature for 12 min, open the mold to obtain the polyurethane material for coal and rock mass.

[0031] Comparative Example 1 The specific preparation process of the polyether polyol for coal and rock mass is as follows: (1) Add 100 g of sucrose, 30 g of diethylene glycol, 76 g of glycerol, and 3.36 g of N,N-dimethylbenzylamine into a 3.5 L autoclave equipped with a stirrer, a meter, a heating temperature control device, a cooling device (including an outer jacket and an inner coil), and a pressure sensor. Fill the autoclave with nitrogen for leak testing. Under the condition of ensuring good sealing of the autoclave, carry out nitrogen replacement. After the nitrogen replacement is completed, vacuum pump 4 g of dimethylamine into it. Then raise the temperature to 82.5 ± 2.5 °C, keep the pressure at 0.25 ± 0.15 MPa, and dropwise add 143 g of ethylene oxide. After the feeding is completed, continue the pressure-holding reaction for 1 h to obtain the intermediate polyether polyol; (2) Raise the temperature in the autoclave to 105 ± 5 °C, maintain the pressure at 0.25 ± 0.15 MPa, add dropwise 571 g of propylene oxide. After the feeding is completed, replenish the pressure to 0.2 MPa and keep the pressure for reaction for 2 h to obtain a crude polyether polyol; (3) When the pressure no longer decreases, keep the crude polyether polyol at 155 °C, bubble nitrogen for 1 h and then discharge the material, and filter to obtain the polyether polyol for mining use.

[0032] The preparation method of the polyurethane material for coal and rock mass includes the following steps: The white material includes the following raw materials in parts by mass: 75 parts of polyether polyol for mining use, 25 parts of TCPP, 0.5 part of bismuth neodecanoate; the black material includes the following raw materials in parts by mass: 75 parts of prepolymer, 25 parts of TCPP; wherein, the prepolymer is prepared by reacting PM-200 and bisphenol A in a mass ratio of 100:8 at 60 °C for 2 h; first mix the above white material and black material respectively, then mix the white material and black material in a mass ratio of 1:1 in a high-speed mixer, and then inject into a mold. After curing at room temperature for 12 min, open the mold to obtain the polyurethane material for coal and rock mass.

[0033] Comparative Example 2 The specific preparation process of the polyether polyol for mining use is as follows: (1) Add 130 g of hexahydroxy triphenylene and 390 g of N,N-dimethylformamide into a 3.5 L autoclave equipped with a stirrer, a meter, a heating temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor. Use triethylamine to adjust the pH of the solution to 10, keep it at 80 °C and stir for 2 h, then add 50 g of solid sorbitol, 60 g of ethylene glycol, 60 g of propylene glycol, and 12.5 g of 2,4,6-tris(dimethylaminomethyl)phenol. Fill nitrogen into the reaction kettle for leak detection. Under the condition of ensuring good sealing of the reaction kettle, conduct nitrogen replacement on it. After nitrogen replacement, raise the temperature to 82.5 ± 2.5 °C, maintain the pressure at 0.25 ± 0.15 MPa, add dropwise 324 g of ethylene oxide. After the feeding is completed, continue to keep the pressure for reaction for 1 h to obtain an intermediate polyether polyol; (2) Raise the temperature in the autoclave to 105 ± 5 °C, maintain the pressure at 0.25 ± 0.15 MPa, add dropwise 757 g of propylene oxide. After the feeding is completed, replenish the pressure to 0.3 MPa and keep the pressure for reaction for 2 h to obtain a crude polyether polyol; (3) When the pressure no longer decreases, keep the crude polyether polyol at 157.5 °C, bubble nitrogen for 1 h and then discharge the material, and filter to obtain the polyether polyol for mining use.

[0034] The preparation method of the polyurethane material for coal and rock mass includes the following steps: The white material comprises raw materials in the following parts by mass: 77.5 parts of mine polyether polyol, 22.5 parts of TCEP, and 0.55 part of bismuth laurate; the black material comprises raw materials in the following parts by mass: 77.5 parts of prepolymer, 22.5 parts of TCEP; wherein, the prepolymer is prepared by reacting PM-200 and diethylene glycol in a mass ratio of 100:11 at 65 °C for 2.5 h; the above-mentioned white material and black material are first mixed separately, and then the white material and black material are stirred in a high-speed mixer in a mass ratio of 1:1, and then injected into a mold. After curing at room temperature for 12 min, the mold is opened to obtain the polyurethane material for coal and rock mass.

[0035] Comparative Example 3 The specific preparation process of the mine polyether polyol is as follows: (1) Add 100 g of hexahydroxy triphenylene and 400 g of N,N-dimethylformamide into a 3.5 L autoclave equipped with a stirrer, a meter, a heating temperature control device, a cooling device (including an outer jacket and an inner coil), and a pressure sensor. Use triethylamine to adjust the pH of the solution to 9, keep it warm at 80 °C and stir for 2 h, then add 40 g of sucrose, 90 g of diethylene glycol, 50 g of glycerol, and 4 g of N,N-dimethylbenzylamine. Fill the reaction kettle with nitrogen for leak detection. Under the condition of ensuring good sealing of the reaction kettle, carry out nitrogen replacement on it. After the nitrogen replacement is completed, vacuum pump in 5.08 g of dimethylamine, then raise the temperature to 82.5 ± 2.5 °C, keep the pressure at 0.25 ± 0.15 MPa, and dropwise add 164 g of ethylene oxide. After the feeding is completed, continue the pressure-retaining reaction for 1 h to obtain an intermediate polyether polyol; (2) Raise the temperature in the autoclave to 105 ± 5 °C, keep the pressure at 0.25 ± 0.15 MPa, dropwise add 654 g of propylene oxide. After the feeding is completed, supplement the pressure to 0.2 MPa and carry out the pressure-retaining reaction for 2 h to obtain a polyether polyol crude product; (3) When the pressure no longer decreases, keep the polyether polyol crude product warm at 155 °C, bubble with nitrogen for 1 h, then discharge the material and filter to obtain the mine polyether polyol.

[0036] The preparation method of the polyurethane material for coal and rock mass includes the following steps: The white material comprises raw materials in the following parts by mass: 75 parts of mine polyether polyol, 25 parts of TCPP, and 0.5 part of neodecanoic acid bismuth; the black material comprises raw materials in the following parts by mass: 75 parts of PM-200, 25 parts of TCPP; the above-mentioned white material and black material are first mixed separately, and then the white material and black material are stirred in a high-speed mixer in a mass ratio of 1:1, and then injected into a mold. After curing at room temperature for 12 min, the mold is opened to obtain the polyurethane material for coal and rock mass.

[0037] The performance of the polyether polyols for mining and the polyurethane materials for coal and rock masses synthesized in Examples 1-3 and Comparative Examples 1-3 was tested. The compressive strength was tested according to the standard GB / T 2567-2008, and the heat of reaction was tested according to the highest reaction temperature in Part 5 of the polymer materials for strengthening coal and rock masses in coal mines AQT-1089-2020. The test results are shown in Tables 1 and 2.

[0038] Table 1 Performance test results of polyether polyols for mining in examples and comparative examples

[0039] Table 2 Performance test results of polyurethane materials for coal and rock masses in examples and comparative examples

[0040] As can be seen from Tables 1 and 2, by comparing Examples 1-3 and Comparative Examples 1-3, under the condition of ensuring the same functionality and hydroxyl value in the design, after adding hexahydroxy triphenylene, the compressive strength was significantly improved. The reason is that the star-shaped benzene ring structure of hexahydroxy triphenylene endows the polyether polyol with high thermal stability and compressive strength. In the black material, by using raw materials containing benzene ring structures as the raw materials for synthesizing prepolymers, through the interaction of benzene rings, the toughness and strength of the material are improved, meeting the strict requirements of mining reinforcement materials for strength and low heat of reaction.

Claims

1. A polyurethane material for coal and rock mass, characterized in that, It is composed of white material and black material in a mass ratio of 1:

1. Among them, the white material includes the following raw materials in parts by mass: 75-80 parts of mine polyether polyol, 20-25 parts of flame retardant, and 0.5-0.6 parts of catalyst; the black material includes the following raw materials in parts by mass: 75-80 parts of prepolymer and 20-25 parts of flame retardant. The mine polyether polyol is prepared by reacting hexahydroxy triphenylene and polyol as a mixed initiator with alkylene oxide under the action of a basic catalyst. The prepolymer is obtained by mixing and reacting polymeric MDI and bisphenol A in a mass ratio of 100: (8-14) at 60-70 °C.

2. The polyurethane material for coal and rock mass according to claim 1, wherein The specific preparation process of the mine polyether polyol is as follows: (1) Dissolve hexahydroxy triphenylene in the solvent N,N-dimethylformamide, add triethylamine to adjust the pH of the solution to 9-11, then add polyol, add a basic catalyst, replace with nitrogen and then raise the temperature under vacuum, keep the temperature at 80-85 °C, the pressure at 0.1-0.4 MPa, dropwise add alkylene oxide, and continue to react for 1-2 h after the feeding is completed to obtain an intermediate polyether polyol. (2) Raise the temperature of the intermediate polyether polyol to 100-110 °C, keep the pressure at 0.1-0.4 MPa, dropwise add alkylene oxide again, supplement the pressure to 0.2-0.3 MPa after the feeding is completed, and keep the pressure and react for 2-3 h to obtain a polyether polyol crude product. (3) Keep the polyether polyol crude product at 155-160 °C, bubble with nitrogen for 1-2 h and then discharge to obtain the mine polyether polyol.

3. The polyurethane material for coal and rock mass according to claim 2, characterized in that, The hexahydroxy triphenylene accounts for 35-50 wt.% of the total amount of the mixed initiator, and the total amount of the mixed initiator is the sum of the amounts of hexahydroxy triphenylene and polyol.

4. The polyurethane material for coal and rock mass according to claim 2, characterized in that, The polyol is one or more of sucrose, solid sorbitol, diethylene glycol, glycerol, ethylene glycol, and propylene glycol.

5. The polyurethane material for coal and rock mass according to claim 2, characterized in that, The basic catalyst is one or more of dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and N,N-dimethylbenzylamine, and the addition amount of the basic catalyst is 0.8-1.0 wt.% of the total amount of the mixed initiator and the total amount of alkylene oxide.

6. The polyurethane material for coal and rock mass according to claim 2, characterized in that, In step (1), the alkylene oxide is ethylene oxide, in step (2), the alkylene oxide is propylene oxide, and the amount of ethylene oxide used in step (1) accounts for 20-40 wt.% of the total amount of alkylene oxide.

7. The polyurethane material for coal and rock mass according to claim 2, wherein The mass ratio of the total amount of the mixed initiator to the total amount of alkylene oxide is 1: (2.90-3.65).

8. The polyurethane material for coal and rock mass according to claim 1, characterized in that, The flame retardant in the white material and the black material is one of tris(1-chloro-2-propyl) phosphate, tris(2-chloroethyl) phosphate, and triethyl phosphate.

9. The polyurethane material for coal and rock mass according to claim 1, wherein The catalyst in the white material is one of bismuth neodecanoate and bismuth laurate.

10. A preparation method of the polyurethane material for coal and rock mass according to any one of claims 1-9, characterized in that, The white material and the black material are first mixed separately, and then the white material and the black material are stirred in a high-speed mixer according to the mass ratio and then injected into a mold for curing and forming to obtain a polyurethane material for coal and rock mass.

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