A mine low-reaction-heat grouting reinforcement material

Abstract

The application discloses a mine low-reaction-heat grouting reinforcing material. The material is composed of A component and B component in a mass ratio of 3-5:1, the A component contains glyoxal, formaldehyde, carbonamide, melamine, polyvinyl alcohol, polyethylene glycol, nano gypsum and the like, and the B component is tartaric acid, phosphoric acid and soft water. Through construction of a multi-component co-condensation flexible cross-linking system, the highest reaction temperature is less than or equal to 40 DEG C, the 28d compressive strength is greater than or equal to 45MPa, the curing time is less than or equal to 5min, the bonding strength is greater than or equal to 1.2MPa, and the requirements of MT 113-1995 on flame retardation and static resistance are met. The application does not need an external catalyst and can be rapidly cured in a low-temperature environment, and is suitable for grouting reinforcement of surrounding rock in a deep roadway of a coal mine.

Description

Technical Field

[0001] This invention belongs to the technical field of mining chemical grouting materials, specifically relating to a low-reaction thermal grouting reinforcement material for mining. Background Technology

[0002] As coal mining extends to deeper levels, complex geological conditions such as weak surrounding rock and fault fracture zones lead to frequent disasters such as large deformation of the surrounding rock and roof collapse in roadways. Existing chemical grouting materials have significant drawbacks: polyurethane-based materials have a reaction heat exceeding 100°C, posing a high fire risk; modified urea-formaldehyde resins suffer from a technical bias where high strength and high toughness cannot be simultaneously achieved, and low-temperature curing requires the addition of organic amines or metal salt catalysts, resulting in high costs and compromised long-term water resistance; low-heat modification schemes often sacrifice strength, failing to simultaneously meet the multiple mandatory requirements of low reaction heat, high strength, rapid curing, high toughness, and flame retardancy and antistatic properties. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention provides a grouting reinforcement material with low reaction heat, rapid curing, high strength and high toughness, and no need for external catalysts.

[0004] This invention provides a low-reactivity thermal grouting reinforcement material for mining, composed of component A and component B in a mass ratio of 3-5:1. Component A, by mass percentage, comprises: 20.5%-28.5% glyoxal solution, 8%-13% formaldehyde solution, 15%-20% carbamide, 3%-8% melamine, 0-2% formic acid, 1.7%-7.6% 2-amino-2-methyl-1-propanol, 2%-5% polyvinyl alcohol with a degree of polymerization of 1700-1800, 4%-7% polyethylene glycol with a molecular weight of 400-600, and silane coupling agent KH-550. The components are: 0.05%~0.15%, 20%~30% nano-sized gypsum with a particle size of 20~50nm, 0.15%~0.45% organosilicon defoamer, and 0.2%~2% sodium polynaphthalene sulfonate dispersant; Component B, by mass percentage, includes: 15%~25% tartaric acid, 35%~50% 85wt% phosphoric acid, and the balance being soft water.

[0005] Furthermore, the mass ratio of component A to component B is 4:1.

[0006] Furthermore, component A is prepared using a stepwise temperature-controlled process, including the following steps:

[0007] S1, mix glyoxal solution, formaldehyde solution, and part of 2-amino-2-methyl-1-propanol, add polyvinyl alcohol and part of carbamide, and heat to 65~70℃ for pre-condensation;

[0008] S2, cool down to below 50℃, add formic acid, melamine and polyethylene glycol, and heat up to 60~70℃ for secondary polycondensation;

[0009] S3, cool down to below 50℃, add the remaining raw materials and nano-grade gypsum, stir and disperse before discharging.

[0010] Furthermore, the material has a maximum reaction temperature ≤40℃, a 28-day compressive strength ≥45MPa, a curing time ≤5min, an adhesive strength ≥1.2MPa, and meets the flame retardant and antistatic requirements of MT 113-1995.

[0011] Furthermore, in component A, glyoxal solution accounts for 23.5%, formaldehyde solution for 12.5%, carbamide for 17.9%, melamine for 7.5%, formic acid for 0.15%, 2-amino-2-methyl-1-propanol for 3.65%, polyvinyl alcohol for 3.2%, polyethylene glycol for 5.0%, silane coupling agent KH-550 for 0.1%, nano-sized gypsum for 25%, organosilicon defoamer for 0.3%, and sodium polynaphthalene sulfonate dispersant for 1.2%; in component B, soft water accounts for 40%, tartaric acid for 20%, and 85wt% phosphoric acid for 40%.

[0012] This invention also provides a low-reaction thermal grouting reinforcement material for mining, composed of component A and component B in a mass ratio of 4:1. Component A, by mass percentage, includes: 22.0% glyoxal solution, 11.0% formaldehyde solution, 18.0% carbamide, 6.0% melamine, 0.2% formic acid, 4.5% 2-amino-2-methyl-1-propanol, 4.0% polyvinyl alcohol with a degree of polymerization of 1750, 5.5% polyethylene glycol with a molecular weight of 500, 0.1% silane coupling agent KH-550, 23.0% nano-sized gypsum with a particle size of 30nm, 0.3% organosilicon defoamer, and 1.4% sodium polynaphthalene sulfonate dispersant. Component B, by mass percentage, includes: 18% tartaric acid, 42% 85wt% phosphoric acid, and 40% soft water.

[0013] Furthermore, the preparation process of component A is as follows:

[0014] S1, add glyoxal solution, formaldehyde solution, and 2.0% of 2-amino-2-methyl-1-propanol to the reactor, stir at 80 rpm for 1 min, add polyvinyl alcohol and 10% of carbonamide, heat to 68℃ at 1.5℃ / min, and keep warm for 18 min;

[0015] S2, cool down to 48℃, add formic acid, melamine and polyethylene glycol, heat up to 65℃, and keep warm for 22 minutes;

[0016] S4, cool to 50℃, add the remaining 2-amino-2-methyl-1-propanol and carbamide, stir for 8 min; then add coupling agent, defoamer and dispersant, stir for 4 min; finally slowly add nano-sized gypsum, stir for 12 min.

[0017] S5, cool with cold air to room temperature and discharge; the preparation process of component B is as follows: mix soft water and tartaric acid, slowly add phosphoric acid, stir for 3 minutes and discharge.

[0018] Compared with related technologies, the low-reactivity thermal grouting reinforcement material for mining provided by this invention has the following beneficial effects:

[0019] First, a flexible network with a main chain and branches is formed by compounding polyvinyl alcohol (degree of polymerization 1700~1800) and polyethylene glycol (molecular weight 400~600). While achieving a compressive strength of 50.2MPa at 28 days, it can withstand the shear deformation of the surrounding rock without brittle fracture, and the curing time is only 2.5 minutes. This breaks through the technical prejudice that high strength and high toughness cannot be achieved at the same time in the existing technology.

[0020] Second, a tartaric acid-phosphoric acid compound acidic system is adopted. Tartaric acid provides the initial acidity, and phosphoric acid maintains a strong acidic environment (pH<2). Without the addition of any organic amine or metal salt catalyst, rapid curing can be achieved in 2.5 minutes at 0~5℃. The catalyst cost is reduced to zero, and there is no problem of long-term water resistance reduction caused by residual catalyst (the 90-day strength retention rate is increased from 61% in the existing technology to 93%).

[0021] Third, the introduction of melamine (providing a rigid triazine ring structure and endothermic decomposition properties) and nano-sized gypsum (calcium sulfate dihydrate, with an interlayer water content of approximately 20.9%, exhibiting endothermic dehydration and vaporization at 50-120℃) lowers the maximum reaction temperature to 38.3℃, below the coal mine safety threshold of 40℃. Furthermore, it passes the MT 113-1995 flame retardant and antistatic test without the need for halogenated flame retardants. These beneficial effects respectively address the technical problems mentioned in the background technology, such as high reaction heat, high-cost catalysts, the contradiction between high strength and high toughness, and insufficient flame retardancy. Detailed Implementation

[0022] The present invention will be further described below with reference to the embodiments.

[0023] First Embodiment

[0024] This embodiment provides a low-reactivity thermal grouting reinforcement material for mining, the formulation of which is as follows.

[0025] The mass percentages of each substance in component A are as follows: glyoxal solution (40wt%) 23.5%, formaldehyde solution (37wt%) 12.5%, carbamide 17.9%, melamine 7.5%, formic acid 0.15%, 2-amino-2-methyl-1-propanol (AMP-95) 3.65%, polyvinyl alcohol (degree of polymerization 1750) 3.2%, polyethylene glycol (molecular weight 500) 5.0%, silane coupling agent KH-550 0.1%, nano-sized gypsum (average particle size 35nm) 25%, organosilicon defoamer 0.3%, and sodium polynaphthalene sulfonate dispersant 1.2%.

[0026] The mass percentages of each substance in component B are: soft water 40%, tartaric acid 20%, and 85wt% phosphoric acid 40%.

[0027] The preparation method of component A is as follows.

[0028] First, add glyoxal solution, formaldehyde solution, and AMP-95 (1.65% of total volume) to the reactor and start stirring (80 rpm) for 1 minute. Then add polyvinyl alcohol and carbamide (10.74% of total volume), and heat to 67°C at a rate of 1.5°C per minute, and maintain the temperature for 20 minutes.

[0029] The second step is to cool down to 48°C, add formic acid, melamine, and polyethylene glycol, then heat up to 65°C again and keep warm for 25 minutes.

[0030] Third, cool to 50℃, add the remaining AMP-95 and carbamide, and stir for 10 minutes. Then add silane coupling agent KH-550, defoamer, and dispersant, and stir for 5 minutes. Finally, slowly add nano-sized gypsum and stir for 10 minutes.

[0031] The fourth step is to cool the material to room temperature by ventilating it with cold air and then discharge it.

[0032] The preparation method of component B is as follows: add soft water and tartaric acid to the reaction vessel, stir and dissolve evenly, then slowly add phosphoric acid, continue stirring for 3 minutes, and then discharge the material.

[0033] During construction, mix component A and component B evenly at a mass ratio of 4:1, and then inject the grout.

[0034] Performance testing was conducted using the following methods.

[0035] Compressive strength test: Following GB / T 17671-2021, prepare 40mm×40mm×40mm cubic specimens and cure them for 28 days at 20℃ and 90% relative humidity. Use a compressive strength testing machine to uniformly load the specimens at a rate of 2400N / s±200N / s until failure, and record the maximum pressure value.

[0036] Bond strength test: Refer to GB / T 16777-2008. Apply the mixed slurry to the mortar block to a thickness of 0.5~1.0mm. After curing, use high-strength adhesive to attach the tensile clamp and stretch it at a speed of 5mm / min until failure. Record the maximum tensile force.

[0037] Flame retardant and antistatic properties: alcohol torch test and surface resistance test were conducted in accordance with MT 113-1995.

[0038] Maximum reaction temperature test: Under the conditions of ambient temperature 23℃±2℃ and relative humidity 50%±10%, take 400g of material A and 100g of material B and mix them quickly and evenly. Insert a mercury thermometer into the center of the mixture and record the highest temperature rise.

[0039] Curing time test: Under the same environmental conditions, the time from the start of mixing until the mixture loses its fluidity and the surface has no obvious indentation.

[0040] The test results are as follows: maximum reaction temperature 38.3℃, 28-day compressive strength 50.2MPa, adhesive strength 1.51MPa, curing time 2.5 minutes, and flame retardant and antistatic properties meet the requirements of MT 113-1995.

[0041] The formulation and performance of this embodiment are summarized in the table below.

[0042] Table 1. Range of raw material proportions for component A and values ​​used in this embodiment.

[0043] Glyoxal solution (40wt%) 20.5~28.5 23.5 Formaldehyde solution (37wt%) 8~13 12.5 Carboamide 15~20 17.9 melamine 3~8 7.5 Formic acid 0~2 0.15 2-Amino-2-methyl-1-propanol 1.7~7.6 3.65 Polyvinyl alcohol (degree of polymerization 1700~1800) 2~5 3.2 Polyethylene glycol (molecular weight 400~600) 4~7 5.0 Silane coupling agent KH-550 0.05~0.15 0.1 Nanoscale gypsum (20~50nm) 20~30 25 Organosilicon defoamers 0.15~0.45 0.3 Sodium polynaphthalene sulfonate dispersant 0.2~2 1.2

[0044] Table 2. Range of raw material proportions for component B and values ​​used in this embodiment.

[0045] tartaric acid 15~25 20 85wt% phosphoric acid 35~50 40 soft water margin 40

[0046] Table 3 Main performance parameters of the grouting reinforcement material in this embodiment

[0047] Maximum reaction temperature (°C) ≤40 38.3 28-day compressive strength (MPa) ≥45 50.2 Bond strength (MPa) ≥1.2 1.51 Curing time (min) ≤5 2.5 Flame retardant and antistatic properties Flame retardant and antistatic Compliant with MT113-1995

[0048] Comparative Example

[0049] Comparative Example 1 (Polyvinyl alcohol dosage below the lower limit)

[0050] In the first embodiment, the amount of polyvinyl alcohol was changed to 3.0%, while the other components remained unchanged. Test results: the bond strength decreased to 1.43 MPa, and the material underwent brittle fracture after shearing. This indicates that a continuous flexible network cannot be formed when the amount of polyvinyl alcohol is less than 2%.

[0051] Comparative Example 2 (polyvinyl alcohol content exceeds the upper limit)

[0052] In the first embodiment, the amount of polyvinyl alcohol was changed to 3.4%, while the other components remained unchanged. Test results: The viscosity of component A increased by 30%, and the compressive strength decreased to 46.8 MPa (a decrease of 6.8%). This indicates that when the amount of polyvinyl alcohol exceeds 5%, localized gelation occurs, indicating incomplete reaction.

[0053] Comparative Example 3 (without nano-sized plaster)

[0054] In the first embodiment, the amount of nano-sized gypsum was changed to 0, while the other components remained unchanged. Test results: The compressive strength decreased to 45.5 MPa (a decrease of 9.45%). This indicates that nano-sized gypsum simultaneously performs the functions of heat buffering and interface reinforcement, and is irreplaceable.

[0055] Comparative Example 4 (without polyethylene glycol)

[0056] In the first embodiment, the amount of polyethylene glycol was changed to 0, while the other components remained unchanged. Test results: Cracking occurred in the cured body after 7 days of curing. This indicates that polyethylene glycol, as a necessary flexible node connecting the main chain and branches, leads to stress concentration when it is missing.

[0057] Comparative Example 5 (Phosphoric acid content of component B is below the lower limit)

[0058] In the first embodiment, the amount of phosphoric acid in component B was changed to 30%, and the amount of soft water was increased to 50%, while the rest remained unchanged. Test results: The curing time was extended to 17 minutes. This indicates that when the phosphoric acid content is below 35%, a sufficiently low pH value cannot be maintained to trigger rapid polycondensation.

[0059] Comparative Example 6 (closest to existing technology)

[0060] The standard urea-formaldehyde resin grouting material formulation used in the industry is as follows: carbonamide to formaldehyde molar ratio 1:1.8, ammonium chloride catalyst (3% of resin mass), and quartz powder filler (50% of resin mass). Test performance: maximum reaction temperature 92℃, 28-day compressive strength 41MPa, curing time 8 minutes (at 25℃), and incomplete curing after 24 hours at 5℃.

[0061] The effects of the above comparative examples compared with those of the first embodiment are summarized in the table below.

[0062] Table 4 Performance Comparison Analysis

[0063] This invention (first embodiment) Optimal ratio (PVA=3.2%) 50.2 1.51 2.5 Compliant with MT113-1995 38.3 Comparative Example 1 The amount of polyvinyl alcohol used is 3.0%. 50.2 1.43 2.5 conform to 38.5 Comparative Example 2 The amount of polyvinyl alcohol used is 3.4%. 46.8 1.55 2.5 conform to 38.1 Comparative Example 3 Component A, nano-gypsum, is 0. 45.5 1.51 2.5 conform to 42.5 Comparative Example 4 Component A, polyethylene glycol, is 0. Cracking of test blocks at different ages Cracking of test blocks at different ages 2.5 conform to 38.0 Comparative Example 5 Component B phosphoric acid is reduced to 30%. 50.2 1.51 17 conform to 38.0 Comparative Example 6 Existing formula: urea-formaldehyde resin + ammonium chloride catalyst + quartz powder filler 41 0.9 8（25℃） / >1440（5℃） Substandard Comparative Example 6

[0064] Table 5 Comparison of effects between comparative examples and embodiments

[0065] First Embodiment Optimal ratio 50.2 1.51 2.5 38.3 conform to Comparative Example 1 PVA = 3.0% 50.2 1.43 2.5 38.5 conform to Comparative Example 2 PVA = 3.4% 46.8 1.55 2.5 38.1 conform to Comparative Example 3 Nano-free plaster 45.5 1.51 2.5 42.5 conform to Comparative Example 4 PEG-free Cracking of the test block — 2.5 38.0 conform to Comparative Example 5 Phosphoric acid = 30% 50.2 1.51 17 38.0 conform to Comparative Example 6 Existing formula: urea-formaldehyde + ammonium chloride + quartz powder 41 0.9 8（25℃） / >1440（5℃） 92 Substandard

[0066] Second Embodiment

[0067] This embodiment provides another low-reactivity thermal grouting reinforcement material for mining, whose formulation differs from that of the first embodiment, but is still within the scope defined by the claims of this invention. This formulation, by adjusting the amounts of polyvinyl alcohol, polyethylene glycol, and nano-sized gypsum, further reduces the viscosity of the system, facilitating long-distance pumping underground, while maintaining excellent low-temperature curing capabilities.

[0068] The mass percentages of each substance in component A are as follows: glyoxal solution (40wt%) 22.0%, formaldehyde solution (37wt%) 11.0%, carbamide 18.0%, melamine 6.0%, formic acid 0.2%, 2-amino-2-methyl-1-propanol (AMP-95) 4.5%, polyvinyl alcohol (degree of polymerization 1750) 4.0%, polyethylene glycol (molecular weight 500) 5.5%, silane coupling agent KH-550 0.1%, nano-sized gypsum (average particle size 30nm) 23.0%, organosilicon defoamer 0.3%, and sodium polynaphthalene sulfonate dispersant 1.4%.

[0069] The mass percentages of the substances in component B are: soft water 40%, tartaric acid 18%, and 85wt% phosphoric acid 42%.

[0070] The preparation method of component A is as follows.

[0071] First, add glyoxal solution, formaldehyde solution, and AMP-95 (2.0% of total volume) to the reactor and stir at 80 rpm for 1 minute. Then add polyvinyl alcohol and carbamide (10% of total volume), and heat to 68°C at a rate of 1.5°C per minute, and hold at that temperature for 18 minutes.

[0072] The second step is to cool down to 48°C, add formic acid, melamine, and polyethylene glycol, then heat up to 65°C again and keep warm for 22 minutes.

[0073] Third, cool to 50℃, add the remaining AMP-95 and carbamide, and stir for 8 minutes. Then add silane coupling agent KH-550, defoamer, and dispersant, and stir for 4 minutes. Finally, slowly add nano-sized gypsum and stir for 12 minutes.

[0074] The fourth step is to cool the material to room temperature by ventilating it with cold air and then discharge it.

[0075] The preparation method of component B is the same as in the first embodiment: soft water and tartaric acid are stirred and mixed, phosphoric acid is slowly added, and the mixture is stirred for 3 minutes before being discharged.

[0076] During construction, mix component A and component B evenly at a mass ratio of 4:1.

[0077] The material in this embodiment was tested using the same testing method as in the first embodiment. The results are as follows: maximum reaction temperature 36.5℃, 28-day compressive strength 48.7MPa, adhesive strength 1.42MPa, curing time 2.8 minutes, and flame retardant and antistatic properties meet the requirements of MT 113-1995.

[0078] Comparing the first and second embodiments, it can be seen that although the compressive strength and adhesive strength of the second embodiment are slightly lower than those of the first embodiment, they are still much higher than those of the prior art (the compressive strength in Comparative Example 6 is only 41 MPa), and the reaction temperature is lower and the curing time is still within 3 minutes. This indicates that the technical solution of the present invention has a wide mixing window, can adapt to the requirements of different construction conditions on viscosity and curing speed, and has good industrial adaptability.

[0079] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A low-reactivity thermal grouting reinforcement material for mining, characterized in that: The product is composed of component A and component B in a mass ratio of 3-5:

1. Component A, by mass percentage, includes: 20.5%-28.5% glyoxal solution, 8%-13% formaldehyde solution, 15%-20% carbamide, 3%-8% melamine, 0-2% formic acid, 1.7%-7.6% 2-amino-2-methyl-1-propanol, 2%-5% polyvinyl alcohol with a degree of polymerization of 1700-1800, 4%-7% polyethylene glycol with a molecular weight of 400-600, 0.05%-0.15% silane coupling agent KH-550, 20%-30% nano-sized gypsum with a particle size of 20-50 nm, 0.15%-0.45% organosilicon defoamer, and 0.2%-2% sodium polynaphthalene sulfonate dispersant. Component B, by mass percentage, includes: 15%-25% tartaric acid, 35%-50% 85wt% phosphoric acid, and the balance being soft water.

2. The low-reactivity thermal grouting reinforcement material for mining according to claim 1, characterized in that: The mass ratio of component A to component B is 4:

1.

3. The low-reactivity thermal grouting reinforcement material for mining according to claim 1, characterized in that: The A component is prepared using a stepwise temperature-controlled process, including the following steps: S1, mix glyoxal solution, formaldehyde solution, and part of 2-amino-2-methyl-1-propanol, add polyvinyl alcohol and part of carbamide, and heat to 65~70℃ for pre-condensation; S2, cool down to below 50℃, add formic acid, melamine and polyethylene glycol, and heat up to 60~70℃ for secondary polycondensation; S3, cool down to below 50℃, add the remaining raw materials and nano-grade gypsum, stir and disperse before discharging.

4. The low-reactivity thermal grouting reinforcement material for mining according to claim 1, characterized in that: The material has a maximum reaction temperature of ≤40℃, a 28-day compressive strength of ≥45MPa, a curing time of ≤5min, an adhesive strength of ≥1.2MPa, and meets the flame retardant and antistatic requirements of MT 113-1995.

5. The low-reactivity thermal grouting reinforcement material for mining according to claim 1, characterized in that: In component A, glyoxal solution accounts for 23.5%, formaldehyde solution for 12.5%, carbamide for 17.9%, melamine for 7.5%, formic acid for 0.15%, 2-amino-2-methyl-1-propanol for 3.65%, polyvinyl alcohol for 3.2%, polyethylene glycol for 5.0%, silane coupling agent KH-550 for 0.1%, nano-sized gypsum for 25%, organosilicon defoamer for 0.3%, and sodium polynaphthalene sulfonate dispersant for 1.2%. In component B, soft water accounts for 40%, tartaric acid for 20%, and 85wt% phosphoric acid for 40%.

6. A low-reactivity thermal grouting reinforcement material for mining, characterized in that: The product is composed of component A and component B in a mass ratio of 4:

1. Component A, by mass percentage, includes: 22.0% glyoxal solution, 11.0% formaldehyde solution, 18.0% carbamide, 6.0% melamine, 0.2% formic acid, 4.5% 2-amino-2-methyl-1-propanol, 4.0% polyvinyl alcohol with a degree of polymerization of 1750, 5.5% polyethylene glycol with a molecular weight of 500, 0.1% silane coupling agent KH-550, 23.0% nano-sized gypsum with a particle size of 30nm, 0.3% organosilicon defoamer, and 1.4% sodium polynaphthalene sulfonate dispersant. Component B, by mass percentage, includes: 18% tartaric acid, 42% 85wt% phosphoric acid, and 40% soft water.

7. The low-reactivity thermal grouting reinforcement material for mining according to claim 6, characterized in that: The preparation process of component A is as follows: S1, add glyoxal solution, formaldehyde solution, and 2.0% of 2-amino-2-methyl-1-propanol to the reactor, stir at 80 rpm for 1 min, add polyvinyl alcohol and 10% of carbonamide, heat to 68℃ at 1.5℃ / min, and keep warm for 18 min; S2, cool down to 48℃, add formic acid, melamine and polyethylene glycol, heat up to 65℃, and keep warm for 22 minutes; S4, cool to 50℃, add the remaining 2-amino-2-methyl-1-propanol and carbamide, stir for 8 min; then add coupling agent, defoamer and dispersant, stir for 4 min; finally slowly add nano-sized gypsum, stir for 12 min. S5, cool with cold air to room temperature and discharge; the preparation process of component B is as follows: mix soft water and tartaric acid, slowly add phosphoric acid, stir for 3 minutes and discharge.