Polyurethane material for coal rock mass and preparation method thereof

Abstract

The present invention belongs to the technical field of polyurethane, and specifically relates to a polyurethane material for coal rock and a preparation method thereof. The polyurethane material for coal rock is composed of a white material and a black material in a mass ratio of 1:1. The white material includes the following raw materials: mining polyether polyol, flame retardant, and catalyst; the black material includes the following raw materials: prepolymer and flame retardant. The polyurethane material for coal rock of the present invention forms a highly cross-linked star structure by introducing hexahydroxytriphenylene with a star-shaped molecular structure into the synthesis of mining polyether polyol, which balances rigidity and flexibility while improving the cross-linking density and compressive strength of the product; secondly, bisphenol A with a benzene ring structure is used as a raw material for synthesizing the prepolymer, and the toughness and strength of the material are improved through the interaction of the benzene rings. The obtained polyurethane material has high compressive strength and low reaction heat, which meets the requirements of polyurethane material for coal rock; the present invention also provides a preparation method thereof, and the preparation process is simple.

Description

Technical Field

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

[0002] In the fields of mining and underground engineering construction, polyurethane materials have become indispensable engineering materials due to their excellent physical and chemical properties. Mining polyether polyols, as the core raw material of polyurethane materials, play a key role in mining reinforcement material systems. Grouting materials, for example, effectively improve tunnel stability by filling cracks and reinforcing surrounding rock. Spray support materials can quickly form a dense protective layer to resist groundwater erosion and surrounding rock deformation, and are widely used in coal mine tunnel maintenance, tunnel anti-seepage reinforcement, and other scenarios.

[0003] The design concept of traditional mining polyether polyols focuses on high reactivity, aiming to meet the urgent need for rapid curing on-site. Although this design strategy can achieve instant molding of materials, its violent exothermic reaction characteristics have brought multiple technical bottlenecks. From a safety perspective, the local temperature rises sharply during the construction process, which can easily reach the ignition point of combustible materials, causing major safety accidents such as gas explosions or dust combustion. At the material performance level, the uneven heat conduction during the curing process leads to the accumulation of internal thermal stress, causing defects such as cracks and deformation in the material, significantly reducing the impact resistance, tensile strength and other mechanical properties of the final product. In addition, the excessively fast curing speed greatly compresses the construction operation window, making it difficult to achieve precise spraying or uniform grouting under conditions with complex geological structures and limited construction space, seriously restricting construction efficiency and project quality.

[0004] CN119306910A discloses a low-reaction-heat reinforcement material for mining and a preparation method thereof. By mixing a bisphenol compound polyether polyol A with a specific initiator and a high-functionality polyether polyol B, the strength of the reinforcement material is ensured while reducing the reaction heat. Furthermore, the use of a polyether polyol C initiated by tetrabromobisphenol A enhances the flame retardancy, toughness, and strength of the prepolymer. The resulting reinforcement material has high compressive strength and low reaction heat, meeting mining 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. This results in high mixing uniformity requirements and strong equipment dependence, leading to complex construction processes during underground mining applications. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention aims to provide a polyurethane material for coal rock mass. By introducing hexahydroxytriphenylene with a star-shaped molecular structure into the synthesis of mining polyether polyols, 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 a prepolymer. Through the interaction of the benzene rings, the toughness and strength of the material are improved. The resulting polyurethane material has high compressive strength and low reaction heat, meeting the requirements of polyurethane materials for coal rock mass. The present invention also provides a preparation method thereof, and the preparation process is simple.

[0006] The polyurethane material for coal rock mass described in the present invention is composed of white material and black material in a mass ratio of 1:1, wherein the white material includes the following raw materials in mass parts: 75-80 parts of mining 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 mass parts: 75-80 parts of prepolymer and 20-25 parts of flame retardant.

[0007] The mining-used polyether polyol is prepared by reacting hexahydroxytriphenylene and polyol as mixed initiators with alkylene oxide under the action of an alkaline catalyst.

[0008] The prepolymer is obtained by mixing polymeric MDI and bisphenol A in a mass ratio of 100:(8-14) at 60-70°C. The polymeric MDI is preferably PM-200, which is purchased from Wanhua Chemical Group Co., Ltd.

[0009] The specific preparation process of the mining polyether polyol is as follows:

[0010] (1) Hexahydroxytriphenylene is dissolved in N,N-dimethylformamide solvent, triethylamine is added to adjust the pH of the solution to 9-11, polyol is then added, alkaline catalyst is added, nitrogen is replaced and the temperature is increased in vacuum, the temperature is maintained at 80-85°C and the pressure is 0.1-0.4 MPa, alkylene oxide is added dropwise, and the reaction is continued for 1-2 hours after the feeding is completed to obtain an intermediate polyether polyol, wherein the hexahydroxytriphenylene and the solvent N,N-dimethylformamide are dissolved to form a uniform solution, and the concentration of the hexahydroxytriphenylene in the solution is 20-30 wt.%;

[0011] (2) The intermediate polyether polyol is heated to 100-110°C, the pressure is maintained at 0.1-0.4 MPa, and alkylene oxide is added dropwise again. After the feeding is completed, the pressure is increased to 0.2-0.3 MPa, and the pressure is maintained for 2-3 hours to obtain a crude polyether polyol polymer;

[0012] (3) The crude polyether polyol is kept warm to 155-160°C, and nitrogen is bubbled for 1-2 hours before being discharged to obtain a mining polyether polyol.

[0013] The hexahydroxytriphenylene accounts for 35-50wt.% of the total amount of the mixed initiator, and the total amount of the mixed initiator is the sum of the amounts of the hexahydroxytriphenylene and the polyol.

[0014] The polyols are selected from the group consisting of sucrose, solid sorbitol, diethylene glycol, glycerol, ethylene glycol and propylene glycol.

[0015] The alkaline catalyst is one or more of dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and N,N-dimethylbenzylamine, and the amount of the alkaline catalyst added is 0.8-1.0 wt.% of the total amount of the mixed initiator and the total amount of the alkylene oxide.

[0016] The alkylene oxide in step (1) is ethylene oxide, the alkylene oxide in step (2) is propylene oxide, and the amount of ethylene oxide in step (1) accounts for 20-40wt.% of the total amount of alkylene oxide.

[0017] The mass ratio of the total amount of the mixed initiator to the total amount of the alkylene oxide is 1:(2.90-3.65).

[0018] 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).

[0019] The catalyst in the white material is one of bismuth neodecanoate and bismuth laurate.

[0020] The preparation method of the polyurethane material for coal rock mass comprises the following steps: firstly mixing white material and black material separately, then stirring the white material and black material in a high-speed mixer according to the mass ratio, injecting them into a mold, and solidifying and forming them to obtain the polyurethane material for coal rock mass.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention introduces hexahydroxytriphenylene into the synthesis of white material mining polyether polyol. With its unique star-shaped molecular structure, each hydroxyl group can independently initiate a polyether chain. By adjusting the amount of alkylene oxide and controlling the length of the branch chain, a highly cross-linked star structure is formed, which balances rigidity and flexibility while improving the cross-linking density and compressive strength, thereby giving the product higher compressive strength and lower reaction heat.

[0023] (2) The present invention uses hexahydroxytriphenylene and polyol as mixed initiators to prepare mining polyether polyol. The core of hexahydroxytriphenylene is a rigid planar structure formed by the fusion of three benzene rings. The rigid multi-ring structure is embedded in the main chain or side chain of the polyether polyol as a "cross-linking node", further restricting the mobility of the molecular chain and reducing the relaxation or slippage of the chain segments at high temperatures, thereby inhibiting thermal degradation and ensuring that the product has excellent thermal stability.

[0024] (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 the benzene rings, the toughness and strength of the material are improved, meeting the product's strict requirements for strength and low reaction heat.

[0025] (4) The polyurethane material for coal rock of the present invention has a simple preparation process. The reaction heat of the prepared polyurethane material for coal rock is below 90.1°C, and the compressive strength can reach above 68.9 MPa. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to Examples and Comparative Examples.

[0027] Unless otherwise specified, the raw materials used in the examples and comparative examples are conventional commercially available raw materials, and the processes used in the examples and comparative examples are conventional methods in the art unless otherwise specified.

[0028] The specific preparation process of the mining polyether polyol is as follows:

[0029] (1) In a 3.5 L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor, hexahydroxytriphenylene was dissolved in a solvent N,N-dimethylformamide, triethylamine was added to adjust the pH of the solution to 9-11, and then polyol and alkaline catalyst were added. Nitrogen was filled into the autoclave to test for leaks. While ensuring that the autoclave was well sealed, nitrogen was replaced. After nitrogen replacement, the temperature was raised to 82.5±2.5°C and the pressure was 0.25±0.15 MPa. Ethylene oxide was added dropwise. After the addition was completed, the pressure was maintained for 1-2 hours to obtain an intermediate polyether polyol.

[0030] (2) Raise the temperature in the autoclave to 105±5°C, maintain the pressure at 0.25±0.15 MPa, add propylene oxide dropwise, and after the feeding is completed, increase the pressure to 0.2-0.3 MPa, maintain the pressure for 2-3 hours, and obtain a crude polyether polyol.

[0031] (3) When the pressure no longer decreases, the crude polyether polyol is kept at 155-160°C, and nitrogen is bubbled for 1-2 hours before being discharged and filtered to obtain a mining polyether polyol.

[0032] The method for preparing the polyurethane material for coal rock mass comprises the following steps:

[0033] The white material includes the following raw materials in parts by mass: 75-80 parts of mining 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; wherein the prepolymer is obtained by mixing PM-200 and bisphenol A in a mass ratio of 100:(8-14) at 60-70°C; the above-mentioned white material and black material are first mixed separately, and then the white material and the black material are stirred in a high-speed mixer in a mass ratio of 1:1, and then injected into a mold and cured to obtain a polyurethane material for coal rock.

[0034] Example 1

[0035] The specific preparation process of the mining polyether polyol is as follows:

[0036] (1) 100 g of hexahydroxytriphenylene and 400 g of N,N-dimethylformamide were added to a 3.5 L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor. The pH of the solution was adjusted to 9 using triethylamine. After the mixture was kept at 80 °C and stirred for 2 h, 40 g of sucrose, 90 g of diethylene glycol, 50 g of glycerol and 4 g of N,N-dimethylbenzylamine were added. The reactor was filled with nitrogen for leak testing. While ensuring that the reactor was well sealed, the nitrogen was replaced. After the nitrogen replacement was completed, 5.08 g of dimethylamine was vacuum-drawn in. The temperature was then raised to 82.5 ± 2.5 °C, the pressure was maintained at 0.25 ± 0.15 MPa, and 171 g of ethylene oxide was added dropwise. After the addition was completed, the pressure was maintained for 1 h to obtain an intermediate polyether polyol.

[0037] (2) The temperature in the autoclave was raised to 105±5°C, the pressure was maintained at 0.25±0.15 MPa, 648 g of propylene oxide was added dropwise, and after the addition was completed, the pressure was increased to 0.25 MPa, and the pressure was maintained for 2.5 h to obtain a crude polyether polyol.

[0038] (3) When the pressure no longer decreases, the polyether polyol crude polymer is kept at 155°C, and nitrogen is bubbled for 1.5 hours before being discharged and filtered to obtain mining polyether polyol.

[0039] The method for preparing the polyurethane material for coal rock mass comprises the following steps:

[0040] The white material includes the following raw materials in parts by mass: 75 parts of mining polyether polyol, 25 parts of TCPP, and 0.5 parts of bismuth neodecanoate; the black material includes the following raw materials in parts by mass: 75 parts of prepolymer and 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 hours; the above-mentioned white material and black material are first mixed separately, and then the white material and the black material are stirred in a high-speed stirrer in a mass ratio of 1:1, and then injected into a mold. After curing at room temperature for 12 minutes, the mold is opened to obtain the polyurethane material for coal rock.

[0041] Example 2

[0042] The specific preparation process of the mining polyether polyol is as follows:

[0043] (1) 130 g of hexahydroxytriphenylene and 390 g of N,N-dimethylformamide were added to a 3.5 L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor. The pH of the solution was adjusted to 10 using triethylamine. The mixture was kept at 80 °C and stirred for 2 h. Then, 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 were added. The reactor was filled with nitrogen for leak testing. While ensuring that the reactor was well sealed, the nitrogen was replaced. After nitrogen replacement, the temperature was raised to 82.5 ± 2.5 °C and the pressure was maintained at 0.25 ± 0.15 MPa. 324 g of ethylene oxide was added dropwise. After the addition was completed, the pressure was maintained for 3 h to obtain an intermediate polyether polyol.

[0044] (2) The temperature in the autoclave was raised to 105±5°C, the pressure was maintained at 0.25±0.15 MPa, 757 g of propylene oxide was added dropwise, and after the addition was completed, the pressure was increased to 0.2 MPa, and the pressure was maintained for 3 h to obtain a crude polyether polyol.

[0045] (3) When the pressure no longer decreases, the crude polyether polyol is kept at 157.5°C, and after nitrogen bubbling for 2 hours, the material is discharged and filtered to obtain a mining polyether polyol.

[0046] The method for preparing the polyurethane material for coal rock mass comprises the following steps:

[0047] The white material includes the following raw materials in parts by mass: 77.5 parts of mining polyether polyol, 22.5 parts of TCEP, and 0.55 parts of bismuth laurate; the black material includes the following raw materials in parts by mass: 77.5 parts of prepolymer and 22.5 parts of TCEP; wherein the prepolymer is prepared by reacting PM-200 and bisphenol A in a mass ratio of 100:11 at 65°C for 2.5 hours; the above-mentioned white material and black material are first mixed separately, and then the white material and the black material are stirred in a high-speed stirrer in a mass ratio of 1:1, and then injected into a mold. After curing at room temperature for 12 minutes, the mold is opened to obtain the polyurethane material for coal rock.

[0048] Example 3

[0049] The specific preparation process of the mining polyether polyol is as follows:

[0050] (1) 130 g of hexahydroxytriphenylene and 303 g of N,N-dimethylformamide were added to a 3.5 L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor. The pH of the solution was adjusted to 11 using triethylamine. After the mixture was kept at 80 °C and stirred for 2 h, 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 were added. The reactor was filled with nitrogen for leak testing. While ensuring that the reactor was well sealed, the nitrogen was replaced. After the nitrogen replacement was completed, 6 g of dimethylamine was vacuum-drawn in. The temperature was then raised to 82.5 ± 2.5 °C, the pressure was maintained at 0.25 ± 0.15 MPa, and 380 g of ethylene oxide was added dropwise. After the addition was completed, the pressure was maintained for 1.5 h to obtain the intermediate polyether polyol.

[0051] (2) The temperature in the autoclave was raised to 105±5°C, the pressure was maintained at 0.25±0.15 MPa, 570 g of propylene oxide was added dropwise, and after the addition was completed, the pressure was increased to 0.3 MPa, and the pressure was maintained for 2 h to obtain a crude polyether polyol.

[0052] (3) When the pressure no longer decreases, the polyether polyol crude polymer is kept at 160°C, and after nitrogen bubbling for 1 hour, the material is discharged and filtered to obtain mining polyether polyol.

[0053] The method for preparing the polyurethane material for coal rock mass comprises the following steps:

[0054] The white material includes the following raw materials in parts by mass: 80 parts of mining polyether polyol, 20 parts of TEP, and 0.6 parts of bismuth neodecanoate; the black material includes the following raw materials in parts by mass: 80 parts of prepolymer and 20 parts of TEP; wherein the prepolymer is prepared by reacting PM-200 and bisphenol A in a mass ratio of 100:14 at 70°C for 3 hours; the above-mentioned white material and black material are first mixed separately, and then the white material and the black material are stirred in a high-speed stirrer in a mass ratio of 1:1, and then injected into a mold. After curing at room temperature for 12 minutes, the mold is opened to obtain the polyurethane material for coal rock.

[0055] Comparative Example 1

[0056] The specific preparation process of the mining polyether polyol is as follows:

[0057] (1) In a 3.5L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor, 100g of sucrose, 30g of diethylene glycol, 76g of glycerol and 3.36g of N,N-dimethylbenzylamine were added, and nitrogen was introduced to test the reactor for leakage. While ensuring that the reactor was well sealed, nitrogen was replaced. After nitrogen replacement, 4g of dimethylamine was vacuum-drawn in, and then the temperature was raised to 82.5±2.5℃, the pressure was maintained at 0.25±0.15MPa, and 143g of ethylene oxide was added dropwise. After the addition was completed, the pressure was maintained for 1h to obtain the intermediate polyether polyol;

[0058] (2) The temperature in the autoclave was raised to 105±5°C, the pressure was maintained at 0.25±0.15 MPa, 571 g of propylene oxide was added dropwise, and after the addition was completed, the pressure was increased to 0.2 MPa, and the pressure was maintained for 2 h to obtain a crude polyether polyol.

[0059] (3) When the pressure no longer decreases, the crude polyether polyol is kept at 155°C, and after nitrogen bubbling for 1 hour, the material is discharged and filtered to obtain a mining polyether polyol.

[0060] The method for preparing the polyurethane material for coal rock mass comprises the following steps:

[0061] The white material includes the following raw materials in parts by mass: 75 parts of mining polyether polyol, 25 parts of TCPP, and 0.5 parts of bismuth neodecanoate; the black material includes the following raw materials in parts by mass: 75 parts of prepolymer and 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 hours; the above-mentioned white material and black material are first mixed separately, and then the white material and the black material are stirred in a high-speed stirrer in a mass ratio of 1:1, and then injected into a mold. After curing at room temperature for 12 minutes, the mold is opened to obtain the polyurethane material for coal rock.

[0062] Comparative Example 2

[0063] The specific preparation process of the mining polyether polyol is as follows:

[0064] (1) 130 g of hexahydroxytriphenylene and 390 g of N,N-dimethylformamide were added to a 3.5 L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor. The pH of the solution was adjusted to 10 using triethylamine. The mixture was kept at 80 °C and stirred for 2 h. Then, 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 were added. The reactor was filled with nitrogen for leak testing. While ensuring that the reactor was well sealed, the nitrogen was replaced. After nitrogen replacement, the temperature was raised to 82.5 ± 2.5 °C and the pressure was maintained at 0.25 ± 0.15 MPa. 324 g of ethylene oxide was added dropwise. After the addition was completed, the pressure was maintained for 1 h to obtain an intermediate polyether polyol.

[0065] (2) The temperature in the autoclave was raised to 105±5°C, the pressure was maintained at 0.25±0.15 MPa, 757 g of propylene oxide was added dropwise, and after the addition was completed, the pressure was increased to 0.3 MPa, and the pressure was maintained for 2 h to obtain a crude polyether polyol.

[0066] (3) When the pressure no longer decreases, the crude polyether polyol is kept at 157.5°C, and after nitrogen bubbling for 1 hour, the material is discharged and filtered to obtain a mining polyether polyol.

[0067] The method for preparing the polyurethane material for coal rock mass comprises the following steps:

[0068] The white material includes the following raw materials in parts by mass: 77.5 parts of mining polyether polyol, 22.5 parts of TCEP, and 0.55 parts of bismuth laurate; the black material includes the following raw materials in parts by mass: 77.5 parts of prepolymer and 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 hours; the above-mentioned white material and black material are first mixed separately, and then the white material and the 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 minutes, the mold is opened to obtain the polyurethane material for coal rock.

[0069] Comparative Example 3

[0070] The specific preparation process of the mining polyether polyol is as follows:

[0071] (1) 100 g of hexahydroxytriphenylene and 400 g of N,N-dimethylformamide were added to a 3.5 L autoclave equipped with a stirrer, a meter, a heating and temperature control device, a cooling device (including an outer jacket and an inner coil) and a pressure sensor. The pH of the solution was adjusted to 9 using triethylamine. After the mixture was kept at 80 °C and stirred for 2 h, 40 g of sucrose, 90 g of diethylene glycol, 50 g of glycerol and 4 g of N,N-dimethylbenzylamine were added. The reactor was filled with nitrogen for leak testing. While ensuring that the reactor was well sealed, the nitrogen was replaced. After the nitrogen replacement was completed, 5.08 g of dimethylamine was vacuum-drawn in. The temperature was then raised to 82.5 ± 2.5 °C, the pressure was maintained at 0.25 ± 0.15 MPa, and 164 g of ethylene oxide was added dropwise. After the addition was completed, the pressure was maintained for 1 h to obtain an intermediate polyether polyol.

[0072] (2) The temperature in the autoclave was raised to 105±5°C, the pressure was maintained at 0.25±0.15 MPa, 654 g of propylene oxide was added dropwise, and after the addition was completed, the pressure was increased to 0.2 MPa, and the pressure was maintained for 2 h to obtain a crude polyether polyol.

[0073] (3) When the pressure no longer decreases, the crude polyether polyol is kept at 155°C, and after nitrogen bubbling for 1 hour, the material is discharged and filtered to obtain a mining polyether polyol.

[0074] The method for preparing the polyurethane material for coal rock mass comprises the following steps:

[0075] The white material includes the following raw materials in parts by mass: 75 parts of mining polyether polyol, 25 parts of TCPP, and 0.5 parts of bismuth neodecanoate; the black material includes the following raw materials in parts by mass: 75 parts of PM-200 and 25 parts of TCPP; the above-mentioned white material and black material are first mixed separately, and then the white material and the black material are stirred in a high-speed mixer in a mass ratio of 1:1, and then injected into the mold. After curing at room temperature for 12 minutes, the mold is opened to obtain the polyurethane material for coal rock.

[0076] The mining polyether polyols and the polyurethane materials for coal rock synthesized in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests. The compressive strength was tested according to the standard GB / T2567-2008, and the reaction heat was tested according to AQT-1089-2020 Polymer Materials for Coal Mine Reinforcement of Coal Rock Mass Part 5: Maximum Reaction Temperature. The test results are shown in Tables 1 and 2.

[0077] Table 1 Performance test results of mining polyether polyols of Examples and Comparative Examples

[0078]

[0079] Table 2 Performance test results of polyurethane materials for coal rock mass of the embodiment and comparative example

[0080]

[0081] It can be seen from Table 1 and Table 2 that, by comparing Examples 1-3 and Comparative Examples 1-3, while ensuring the same design functionality and hydroxyl value, the compressive strength is significantly improved after the addition of hexahydroxytriphenylene. The reason is that the star-shaped benzene ring structure of hexahydroxytriphenylene gives the polyether polyol high thermal stability and compressive strength, and the black material uses a raw material containing a benzene ring structure as a raw material for synthesizing the prepolymer. Through the interaction of the benzene rings, the toughness and strength of the material are improved, which meets the strict requirements of the mining reinforcement material for strength and low reaction heat.

Claims

1. A polyurethane material for coal rock mass, characterized in that: It is composed of white material and black material in a mass ratio of 1:1, wherein the white material includes the following raw materials in mass parts: mining polyether polyol 75-80 parts, flame retardant 20-25 parts, catalyst 0.5-0.6 parts; the black material includes the following raw materials in mass parts: prepolymer 75-80 parts, flame retardant 20-25 parts; The specific preparation process of the mining polyether polyol is as follows: (1) Dissolve hexahydroxytriphenylene in N,N-dimethylformamide solvent, add triethylamine to adjust the pH of the solution to 9-11, then add polyol, add alkaline catalyst, replace with nitrogen, and heat in vacuum, maintaining the temperature at 80-85°C and the pressure at 0.1-0.4 MPa, add alkylene oxide dropwise, and continue the reaction for 1-2 hours after the feeding is completed to obtain the intermediate polyether polyol; (2) The intermediate polyether polyol is heated to 100-110°C, the pressure is maintained at 0.1-0.4 MPa, and alkylene oxide is added dropwise again. After the feeding is completed, the pressure is increased to 0.2-0.3 MPa, and the pressure is maintained for 2-3 hours to obtain a crude polyether polyol polymer; (3) The crude polyether polyol is kept at 155-160°C, and nitrogen is bubbled for 1-2 hours before being discharged to obtain a mining polyether polyol; The polyol is a variety of sucrose, solid sorbitol, diethylene glycol, glycerol, ethylene glycol, and propylene glycol; The alkylene oxide in step (1) is ethylene oxide, and the alkylene oxide in step (2) is propylene oxide; The prepolymer is obtained by mixing polymerized MDI and bisphenol A in a mass ratio of 100:(8-14) at 60-70°C.

2. The polyurethane material for coal rock mass according to claim 1, characterized in that: The hexahydroxytriphenylene accounts for 35-50wt.% of the total amount of the mixed initiator, and the total amount of the mixed initiator is the sum of the amounts of the hexahydroxytriphenylene and the polyol.

3. The polyurethane material for coal rock mass according to claim 1, characterized in that: The alkaline catalyst is one or more of dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and N,N-dimethylbenzylamine, and the amount of the alkaline catalyst added is 0.8-1.0 wt.% of the total amount of the mixed initiator and the total amount of the alkylene oxide.

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

5. The polyurethane material for coal rock mass according to claim 1, characterized in that: The mass ratio of the total amount of the mixed initiator to the total amount of the alkylene oxide is 1:(2.90-3.65).

6. The polyurethane material for coal 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.

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

8. A method for preparing the polyurethane material for coal rock mass according to any one of claims 1 to 7, 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 stirrer according to a mass ratio, injected into a mold, and solidified to obtain a polyurethane material for coal rock mass.

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