Coal rock body low-temperature double-liquid reinforcing material and preparation method thereof

Abstract

This invention belongs to the technical field of coal and rock mass reinforcement materials, specifically relating to a low-temperature two-liquid reinforcement material for coal and rock masses and its preparation method. The low-temperature two-liquid reinforcement material for coal and rock masses of this invention comprises component A and component B; by mass parts, component A includes: 70-90 parts of melamine-modified urea-formaldehyde resin, 5-10 parts of ammonia water, 0.2-0.6 parts of emulsifier, 0.1-0.6 parts of defoamer, 0.5-2 parts of ethylene urea, 0.5-2 parts of organic carboxylic acid ester, 0.3-0.9 parts of nano-silica, 0.2-1.2 parts of silane coupling agent, and 5-15 parts of activated ultrafine fly ash; component B includes: 20-50 parts of phosphoric acid solution, 50-70 parts of water, and 3-7 parts of ammonium chloride. The low-temperature two-liquid reinforcement material for coal and rock masses of this invention can rapidly solidify under low-temperature conditions and has high compressive strength, making it suitable for coal and rock mass reinforcement projects in complex coal mine environments.

Description

Technical Field

[0001] This invention belongs to the technical field of reinforcement materials for coal and rock masses, specifically relating to a low-temperature dual-liquid reinforcement material for coal and rock masses and its preparation method. Background Technology

[0002] my country has abundant and widely distributed coal resources, covering multiple regions. Due to complex and variable geological conditions, the stratigraphic structure in most areas is also quite complex. Furthermore, coal-bearing geological structures are typically fragmented, with high ground stress and low geological strength. Therefore, during coal mining, working faces, roadways, and triangular areas all require reinforcement.

[0003] Currently, commonly used reinforcement materials include clay, cement, cement-water glass, ultrafine cement, acrylamide, epoxy resin, and polyurethane. However, traditional inorganic materials such as clay and cement suffer from low strength and inconvenient handling. Among existing grouting materials, acrylamide materials have poor durability and high toxicity, while epoxy resins, although possessing strong adhesion, have high viscosity, making grouting difficult. Polyurethane materials, although exhibiting good adhesion and durability, have poor flame retardancy and high reaction temperatures, posing safety hazards.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0005] The purpose of this invention is to provide a low-temperature dual-liquid reinforcement material for coal and rock masses and its preparation method, so as to help solve or improve the problem that the performance of reinforcement materials in the prior art needs to be further improved.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a low-temperature two-liquid reinforcement material for coal and rock masses, comprising component A and component B; by mass parts, component A comprises: 70-90 parts of melamine-modified urea-formaldehyde resin, 5-10 parts of ammonia water, 0.2-0.6 parts of emulsifier, 0.1-0.6 parts of defoamer, 0.5-2 parts of ethylene urea, 0.5-2 parts of organic carboxylic acid ester, 0.3-0.9 parts of nano-silica, 0.2-1.2 parts of silane coupling agent, and 5-15 parts of activated ultrafine fly ash; the activated ultrafine fly ash is prepared by a method comprising the following steps: calcining ultrafine fly ash that can pass through a 1250-mesh sieve at 600℃ for 2 hours; by mass parts, component B comprises: 20-50 parts of phosphoric acid solution, 50-70 parts of water, and 3-7 parts of ammonium chloride.

[0007] Preferably, the solid content of the melamine-modified urea-formaldehyde resin is ≥50%.

[0008] Preferably, the ultrafine fly ash has an alumina content of 25%-35%, a silica content of 55%-65%, and a calcium oxide content of 2%-8%.

[0009] Preferably, the ethylene urea is N-hydroxymethylethylene urea.

[0010] Preferably, the emulsifier is a polyoxyethylene ether emulsifier or a polyether emulsifier; the defoamer is an organosilicon defoamer or a polyether-modified silicone defoamer.

[0011] Preferably, the concentration of the ammonia solution is 20wt%-30wt%, and the product grade is superior; the concentration of the phosphoric acid solution is 20wt%-50wt%.

[0012] Preferably, the mass ratio of component A to component B is (3-5):1.

[0013] Preferably, the organic carboxylic acid ester is tributyl citrate.

[0014] This invention also provides a method for preparing the low-temperature two-liquid reinforcement material for coal and rock masses as described above, which adopts the following technical solution: The method for preparing the low-temperature two-liquid reinforcement material for coal and rock masses as described above includes the following steps: Preparation of component A: The melamine-modified urea-formaldehyde resin is added to a first container, and ammonia, emulsifier, defoamer, silane coupling agent, organic carboxylic acid ester and ethylene urea are added sequentially while stirring. Stirring is continued, and then the activated ultrafine fly ash and nano silica are added and dispersed at high speed to obtain component A; Preparation of component B: The phosphoric acid solution is added to a second container, and water and ammonium chloride are added and stirred to obtain component B.

[0015] Beneficial effects: The low-temperature dual-liquid reinforcement material for coal and rock masses of the present invention can be rapidly cured under low-temperature conditions, and has the characteristics of high compressive strength, low reaction temperature and excellent flame retardancy. It helps to solve or improve the problems of existing high-temperature reinforcement materials, such as large construction safety hazards (if the reaction temperature of the reinforcement material is too high during the construction of chemical grouting reinforcement materials in coal mines, it may cause smoke and fire during construction) and insufficient mechanical properties. It is suitable for coal and rock mass reinforcement projects in complex coal mine environments.

[0016] The reaction temperature controllability of the low-temperature dual-liquid reinforcement material for coal and rock masses of the present invention is significantly improved. In a downhole environment of 10-25℃, the reaction temperature fluctuation range after slurry mixing is ≤5℃, and there is no reaction stagnation or overheating and boiling phenomenon.

[0017] The low-temperature dual-liquid reinforcement material for coal and rock masses of the present invention has a complete curing time of ≤10 minutes in an environment of 10-25℃, and the early strength of the solidified body is greatly improved. The compressive strength can reach 10MPa in 30 minutes, 20MPa in 24 hours, and 40MPa in 3 days, which can meet the strength requirements for rapid reinforcement of fractured coal seams underground. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 The test block prepared for Example 1; Figure 2 The fracture state of the test block prepared in Example 2 after the 3-day compressive strength test; Figure 3 The fracture state of the specimen prepared in Example 3 after a 3-day compressive strength test; Figure 4 The fracture state of the specimen prepared in Example 4 after a 3-day compressive strength test; Figure 5 The compressive state of the 3d compressive strength test of the specimen prepared in Example 5. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0020] The present invention will now be described in detail with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0021] This invention addresses the issue that the performance of reinforcement materials needs further improvement by providing a low-temperature dual-liquid reinforcement material for coal and rock masses.

[0022] The low-temperature two-liquid reinforcement material for coal and rock masses according to embodiments of the present invention includes component A and component B; by mass parts, component A includes: 70-90 parts (e.g., 70, 75, 80, 85, or 90 parts) of melamine-modified urea-formaldehyde resin, 5-10 parts (e.g., 5, 6, 7, 8, 9, or 10 parts) of ammonia water, and 0.2-0.6 parts (e.g., 0.2, 0.3, 0.4, 0.5, 0.6, 0.6, 0.7, 0.8, 0.9, 0.1 ... 0.5 or 0.6 parts), defoamer 0.1-0.6 parts (e.g., 0.1, 0.2, 0.3, 0.4, 0.5, or 0.6 parts), ethylene urea 0.5-2 parts (e.g., 0.5, 0.8, 1, 1.4, 1.7, or 2 parts), organic carboxylic acid ester 0.5-2 parts (e.g., 0.5, 0.8, 1, 1.4, 1.7, or 2 parts), nano silica 0.3 -0.9 parts (e.g., 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9 parts), 0.2-1.2 parts (e.g., 0.2, 0.5, 0.8, 1.0, or 1.2 parts) of silane coupling agent, and 5-15 parts (e.g., 5, 8, 10, 12, or 15 parts) of activated ultrafine fly ash; the activated ultrafine fly ash is prepared by a method comprising the following steps: Ultrafine fly ash that can pass through a 1250-mesh sieve is calcined at 600℃ for 2 hours. Component B, by weight, comprises: 20-50 parts of phosphoric acid solution (e.g., 20, 25, 30, 35, 40, 45, or 50 parts), 50-70 parts of water (e.g., 50, 55, 60, 35, 40, 45, or 50 parts), and 3-7 parts of ammonium chloride (e.g., 3, 4, 5, 6, or 7 parts). If the proportion of phosphoric acid is too high, the gelation and curing time of the reinforcing material will be significantly accelerated, and the adhesive may gel and cure too quickly, which is detrimental to grouting. If the proportion of phosphoric acid is too low, the curing time of the reinforcing material will be slowed down, and the adhesive may not cure for a long time or may not cure completely, resulting in reduced strength. In this invention, ammonium chloride mainly serves to accelerate the curing speed of melamine-modified urea-formaldehyde resin and can also optimize the curing process and adhesive layer properties.

[0023] The reinforcing material of this invention can achieve low-temperature curing with a small temperature rise. The core principle is that phosphoric acid, through a triple action of "catalytic regulation, cross-linking participation, and heat control," synergistically adapts to the molecular structure of melamine-modified urea-formaldehyde resin, balancing reactivity and energy release. The principle of this invention is that phosphoric acid, as a moderately strong acid, can dissociate H+ at room temperature and low temperatures. +This process significantly reduces the activation energy of the hydroxymethylation and condensation reactions between amino groups and formaldehyde in melamine-modified urea-formaldehyde resin, allowing for curing without the need for heating. Simultaneously, adjusting the pH to 1.5-2.5 guides the formation of methylene bonds, reducing the formation of exothermic ether bonds and suppressing overheating through the reaction pathway. Furthermore, the hydroxyl groups of phosphoric acid form phosphate ester bonds with the resin's hydroxymethyl / amino groups, and the triazine ring forms PN coordination bonds with phosphoric acid, enhancing the stability of the crosslinking network and inhibiting vigorous crosslinking of molecular chains through coordination, thus preventing concentrated exothermic reactions. Regarding heat management, the phosphoric acid concentration gradient allows the reaction to proceed gradually, and the high viscosity limits localized heat accumulation. Water in the aqueous solution dissipates heat through both sensible heat absorption and latent heat of vaporization, further reducing the temperature rise. Meanwhile, the low molecular weight and high hydroxymethyl content of the melamine-modified urea-formaldehyde resin enhance its reactivity at room temperature and low temperatures, while the steric hindrance of the melamine triazine ring reduces excessive crosslinking, preventing exothermic superposition.

[0024] Furthermore, the ester groups in organic carboxylic acid ester molecules can undergo mild cross-linking with the hydroxyl groups on the melamine-urea-formaldehyde resin molecular chain, pre-constructing a pre-cross-linked framework under low-temperature conditions. Combined with the cross-linking strengthening effect of ethylene urea, this shortens the strength development cycle. The silanol groups of the silane coupling agent can chemically react with the siloxy groups in activated ultrafine fly ash and the amino groups in melamine-urea-formaldehyde resin, enhancing the interfacial bonding force between the ultrafine fly ash and the resin matrix and reducing interfacial gaps. Nano-silica can fill the tiny pores between activated ultrafine fly ash particles, forming a dense filled structure, while the nanoparticles can also enhance the rigidity of the resin matrix.

[0025] The low-temperature dual-liquid reinforcement material for coal and rock masses of the present invention can be rapidly cured under low-temperature conditions, and has the characteristics of high compressive strength, low reaction temperature (the reaction temperature of reinforcement materials in the prior art is usually around 85°C, while the reaction temperature of the low-temperature dual-liquid reinforcement material for coal and rock masses of the present invention can be reduced to below 40°C, which is suitable for the field of low-temperature technology of chemical grouting materials for coal mines), and excellent flame retardancy. It helps to solve or improve the problems of large construction safety hazards of existing high-temperature reinforcement materials (if the reaction temperature of the reinforcement material is too high during the construction of chemical grouting reinforcement materials for coal mines, it may cause smoke and fire during construction) and insufficient mechanical properties. It is suitable for coal and rock mass reinforcement projects in complex coal mine environments.

[0026] In a preferred embodiment of the low-temperature two-liquid reinforcement material for coal and rock masses of the present invention, the solid content of the melamine-modified urea-formaldehyde resin is ≥50%, and the molar ratio of urea, formaldehyde, and melamine is 1:(1.8-2):(0.05-0.15). The molar ratio of urea, formaldehyde, and melamine refers to the molar ratio of the three raw materials used in the preparation of the melamine-modified urea-formaldehyde resin. If the proportion of melamine used is too high, the pot life will be shortened, and melamine is expensive; if the proportion of melamine used is too low, the formaldehyde release may exceed the standard in the later stages. If the proportion of urea used is too high, the crosslinking point spacing will increase, and the compressive strength will decrease; if the proportion of urea used is too low, the free formaldehyde content will increase several times, resulting in a strong pungent odor on site.

[0027] In a preferred embodiment of the low-temperature dual-liquid reinforcement material for coal and rock masses of the present invention, the ultrafine fly ash has an alumina content of 25%-35%, a silica content of 55%-65%, and a calcium oxide content of 2%-8%.

[0028] In a preferred embodiment of the low-temperature two-liquid reinforcement material for coal and rock masses of the present invention, the ethylene urea is N-hydroxymethylethylene urea.

[0029] In a preferred embodiment of the low-temperature two-liquid reinforcement material for coal and rock masses of the present invention, the emulsifier is a polyoxyethylene ether emulsifier or a polyether emulsifier; the defoamer is an organosilicon defoamer.

[0030] Preferably, the defoamer is a polyether-modified silicone defoamer.

[0031] In a preferred embodiment of the low-temperature two-liquid reinforcement material for coal and rock masses of the present invention, the concentration of ammonia water is 20wt%-30wt% (e.g., 20wt%, 22wt%, 24wt%, 26wt%, 28wt% or 30wt%), and the product grade is superior; the concentration of phosphoric acid solution is 20wt%-50wt% (e.g., 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt% or 50wt%).

[0032] In a preferred embodiment of the low-temperature dual-liquid reinforcement material for coal and rock masses of the present invention, the mass ratio of component A to component B is (3-5):1 (e.g., 3:1, 3.5:1, 4:1, 4.5:1 or 5:1).

[0033] In a preferred embodiment of the low-temperature two-liquid reinforcement material for coal and rock masses of the present invention, the organic carboxylic acid ester is tributyl citrate.

[0034] This invention also proposes a method for preparing a low-temperature two-liquid reinforcement material for coal and rock masses. The preparation method of the low-temperature two-liquid reinforcement material for coal and rock masses in this embodiment includes the following steps: Preparation of component A: Melamine-modified urea-formaldehyde resin is added to a first container, and ammonia, emulsifier, defoamer and ethylene urea are added sequentially while stirring. Stirring is continued, and then activated ultrafine fly ash and nano-silica are added and dispersed to obtain component A; Preparation of component B: Phosphoric acid solution is added to a second container, water and ammonium chloride are added and stirred to obtain component B.

[0035] The following detailed description of the low-temperature dual-liquid reinforcement material for coal and rock masses and its preparation method, through specific embodiments, illustrates the present invention.

[0036] The main raw materials used in the following examples are sourced from the following sources: the defoamer is a polyether-modified silicone defoamer, Tianjin Gaotian New Material Technology Co., Ltd., model CK-870; the emulsifier is fatty alcohol polyoxyethylene ether AEO-9; the ammonia solution has a mass concentration of 25%-27%, Shandong Hengchang Shengcheng Chemical Co., Ltd.; the phosphoric acid solution has a mass concentration of 85%, Wengfu (Group) Co., Ltd.; melamine-modified urea-formaldehyde resin and urea-formaldehyde resin are purchased from Shandong Li'ang New Material Technology Co., Ltd.; the silane coupling agent KH550 is from Kangjin New Material Technology Co., Ltd.; nano silica is from Zhongyu Wohao New Material (Dongguan) Co., Ltd.; and tributyl citrate is from Zhengzhou Hengfeng New Material Technology Co., Ltd.

[0037] Example 1 The low-temperature two-liquid reinforcement material for coal and rock masses in this embodiment is composed of component A and component B mixed in a mass ratio of 3.6:1. Component A is made from the following raw materials in parts by weight: 86.9 parts melamine-modified urea-formaldehyde resin, 5 parts ammonia water, 0.3 parts defoamer, 0.3 parts emulsifier, 0.5 parts ethylene urea, 7 parts activated ultrafine fly ash, 0.3 parts silane coupling agent, 0.5 parts tributyl citrate, and 0.5 parts nano silica. The activated ultrafine fly ash is prepared by a method including the following steps: calcining ultrafine fly ash that can pass through a 1250-mesh sieve at 600°C for 2 hours. Component B is made from the following raw materials in parts by weight: 25.6 parts phosphoric acid solution, 71.2 parts water, and 3.2 parts ammonium chloride.

[0038] Specifically, the preparation method of component A is as follows: melamine-modified urea-formaldehyde resin is added to the first container, stirring is started, and ammonia, emulsifier, defoamer, ethylene urea, silane coupling agent, and tributyl citrate are added in sequence. After stirring for 1 hour, activated ultrafine fly ash and nano silica are added, and the mixture is dispersed at high speed for 30 minutes. The mixture is then discharged from the discharge port, inspected, filled and sealed to obtain component A. The preparation method of component B is as follows: add phosphoric acid solution to the second container, add water and ammonium chloride, stir for 15 minutes, discharge from the discharge port, inspect, fill and seal to obtain component B.

[0039] Example 2 The low-temperature dual-liquid reinforcement material for coal and rock masses in this embodiment is composed of component A and component B mixed in a mass ratio of 4:1. Component A is made from the following raw materials in parts by weight: 85.8 parts melamine-modified urea-formaldehyde resin, 5 parts ammonia water, 0.2 parts defoamer, 0.4 parts emulsifier, 0.7 parts ethylene urea, 7.9 parts activated ultrafine fly ash, 0.3 parts silane coupling agent, 0.5 parts tributyl citrate, and 0.5 parts nano silica. The activated ultrafine fly ash is prepared by a method including the following steps: calcining ultrafine fly ash that can pass through a 1250-mesh sieve at 600°C for 2 hours. Component B is made from the following raw materials in parts by weight: 29.7 parts phosphoric acid solution, 65 parts water, and 5.3 parts ammonium chloride.

[0040] Specifically, the preparation method of component A is as follows: melamine-modified urea-formaldehyde resin is added to the first container, stirring is started, and ammonia, emulsifier, defoamer, ethylene urea, silane coupling agent, and tributyl citrate are added in sequence. After stirring for 70 minutes, activated ultrafine fly ash and nano silica are added, and high-speed dispersion is carried out for 30 minutes. The mixture is discharged from the discharge port, inspected, filled and sealed to obtain component A. The preparation method of component B is as follows: add phosphoric acid solution to the second container, add water and ammonium chloride, stir for 15 minutes, discharge from the discharge port, inspect, fill and seal to obtain component B.

[0041] Example 3 The low-temperature two-liquid reinforcement material for coal and rock masses in this embodiment is composed of component A and component B mixed in a mass ratio of 4.5:1. Component A is made from the following raw materials in parts by weight: 83.4 parts melamine-modified urea-formaldehyde resin, 5 parts ammonia water, 0.4 parts defoamer, 0.2 parts emulsifier, 1 part ethylene urea, 10 parts activated ultrafine fly ash, 0.3 parts silane coupling agent, 0.5 parts tributyl citrate, and 0.5 parts nano silica. The activated ultrafine fly ash is prepared by a method including the following steps: calcining ultrafine fly ash that can pass through a 1250-mesh sieve at 600°C for 2 hours. Component B is made from the following raw materials in parts by weight: 33.4 parts phosphoric acid solution, 60.4 parts water, and 6.2 parts ammonium chloride.

[0042] Specifically, the preparation method of component A is as follows: melamine-modified urea-formaldehyde resin is added to the first container, stirring is started, and ammonia, emulsifier, defoamer, ethylene urea, silane coupling agent, and tributyl citrate are added in sequence. After stirring for 80 minutes, activated ultrafine fly ash and nano silica are added, and high-speed dispersion is carried out for 30 minutes. The mixture is discharged from the discharge port, inspected, filled and sealed to obtain component A. The preparation method of component B is as follows: add phosphoric acid solution to the second container, add water and ammonium chloride, stir for 15 minutes, discharge from the discharge port, inspect, fill and seal to obtain component B.

[0043] Example 4 The low-temperature two-liquid reinforcement material for coal and rock masses in this embodiment is composed of component A and component B mixed in a mass ratio of 5:1. Component A is made from the following raw materials in parts by weight: 76.8 parts melamine-modified urea-formaldehyde resin, 9 parts ammonia water, 0.1 parts defoamer, 0.3 parts emulsifier, 1.3 parts ethylene urea, 12.5 parts activated ultrafine fly ash, 0.3 parts silane coupling agent, 0.5 parts tributyl citrate, and 0.5 parts nano silica. The activated ultrafine fly ash is prepared by a method including the following steps: calcining ultrafine fly ash that can pass through a 1250-mesh sieve at 600°C for 2 hours. Component B is made from the following raw materials in parts by weight: 33.4 parts phosphoric acid solution, 60.4 parts water, and 6.2 parts ammonium chloride.

[0044] Specifically, the preparation method of component A is as follows: melamine-modified urea-formaldehyde resin is added to the first container, stirring is started, and ammonia, emulsifier, defoamer, ethylene urea, silane coupling agent, and tributyl citrate are added in sequence. After stirring for 1.5 hours, activated ultrafine fly ash and nano silica are added, and the mixture is dispersed at high speed for 30 minutes. The mixture is then discharged from the discharge port, inspected, filled and sealed to obtain component A. The preparation method of component B is as follows: add phosphoric acid solution to the second container, add water and ammonium chloride, stir for 15 minutes, discharge from the discharge port, inspect, fill and seal to obtain component B.

[0045] Example 5 The low-temperature two-liquid reinforcement material for coal and rock masses in this embodiment is composed of component A and component B mixed in a mass ratio of 5.5:1. Component A is made from the following raw materials in parts by weight: 81.9 parts melamine-modified urea-formaldehyde resin, 7 parts ammonia water, 0.3 parts defoamer, 0.3 parts emulsifier, 1.8 parts ethylene urea, 8.7 parts activated ultrafine fly ash, 0.3 parts silane coupling agent, 0.5 parts tributyl citrate, and 0.5 parts nano silica. The activated ultrafine fly ash is prepared by a method including the following steps: calcining ultrafine fly ash that can pass through a 1250-mesh sieve at 600°C for 2 hours. Component B is made from the following raw materials in parts by weight: 40.3 parts phosphoric acid solution, 55 parts water, and 4.7 parts ammonium chloride.

[0046] Specifically, the preparation method of component A is as follows: melamine-modified urea-formaldehyde resin is added to the first container, stirring is started, and ammonia, emulsifier, defoamer, ethylene urea, silane coupling agent, and tributyl citrate are added in sequence. After stirring for 2 hours, activated ultrafine fly ash and nano silica are added, and the mixture is dispersed at high speed for 30 minutes. The mixture is then discharged from the discharge port, inspected, filled and sealed to obtain component A. The preparation method of component B is as follows: add phosphoric acid solution to the second container, add water and ammonium chloride, stir for 15 minutes, discharge from the discharge port, inspect, fill and seal to obtain component B.

[0047] Comparative Example 1 The only difference between this comparative example and Example 1 is that the phosphoric acid solution in component B is replaced with an equal mass of ammonium chloride; all other aspects are the same as in Example 1.

[0048] Comparative Example 2 The only difference between this comparative example and Example 4 is that the activated ultrafine fly ash in component A is replaced with an equal mass of melamine-modified urea-formaldehyde resin; all other aspects remain the same as in Example 4.

[0049] Comparative Example 3 The only difference between this comparative example and Example 5 is that the ultrafine fly ash in component A is replaced with 600 mesh fly ash; all other aspects are the same as in Example 5.

[0050] Comparative Example 4 The only difference between this comparative example and Example 2 is that the melamine-modified urea-formaldehyde resin in component A is replaced with unmodified urea-formaldehyde resin; all other aspects remain the same as in Example 2.

[0051] Comparative Example 5 The only difference between this comparative example and Example 3 is that the ethylene urea in component A is replaced with an equal mass of water; all other aspects remain the same as in Example 3.

[0052] Comparative Example 6 The only difference between this comparative example and Example 5 is that the activated ultrafine fly ash in component A is replaced with an equal mass of talc powder; all other aspects remain the same as in Example 5.

[0053] Comparative Example 7 The only difference between this comparative example and Example 5 is that the activated ultrafine fly ash in component A is replaced with an equal mass of limestone powder; all other aspects remain the same as in Example 5.

[0054] Comparative Example 8 The only difference between this comparative example and Example 1 is that no organic carboxylic acid ester is added to component A, which is replaced with an equal mass of melamine urea-formaldehyde resin. All other aspects are the same as in Example 1.

[0055] Comparative Example 9 The only difference between this comparative example and Example 2 is that nano-silica and silane coupling agent are not added to component A, but are replaced with an equal mass of melamine urea-formaldehyde resin. All other aspects are the same as in Example 2.

[0056] Comparative Example 10 The only difference between this comparative example and Example 1 is that ultrafine fly ash is used instead of activated ultrafine fly ash (i.e., the step of activating ultrafine fly ash is omitted, and ultrafine fly ash is directly applied to the low-temperature two-liquid reinforcement material for coal and rock mass of the present invention); all other aspects are consistent with Example 1.

[0057] Experimental Example Mix components A and B in the specified ratio, stir for 10 seconds, and immediately pour into the mold; test the performance of the grouting material at the corresponding curing age. The performance of the reinforcement materials prepared in the above examples and comparative examples was tested according to the test methods in standard AQ / T 1089-2020 "Polymer Materials for Reinforcing Coal and Rock Masses in Coal Mines" (the test block of Example 1 is shown in the figure). Figure 1 As shown; the 3d compressive strength test results of the specimens in Examples 2-5 are as follows. Figure 2-5 As shown in the figure, the ambient temperature is 25℃.

[0058] The breakage states of the specimens in Examples 2-4 after the 3d compressive strength test are as follows: Figure 2-4 As shown in the figure, Figure 2-3 (The interior is relatively dry); the compressive state of the 3d compressive strength test of the specimen in Example 5 is as follows: Figure 5 As shown (the compressive deformation of the specimens in Examples 4 and 5 is greater).

[0059] The test results are shown in the table below: Table 1

[0060] It can be seen from Table 1 above: In Comparative Example 1, although the reaction temperature was slightly lower after replacing phosphoric acid with ammonium chloride, the setting time and compressive strength were significantly different from those in Example 1, especially the setting time, which increased by 200% in the initial setting time and 209% in the final setting time. This shows that phosphoric acid is a better acid catalyst.

[0061] In Comparative Example 2, although the setting time and compressive strength were slightly improved after the activated ultrafine fly ash was replaced with melamine-modified urea-formaldehyde resin, the expansion ratio was significantly lower than that of the example. This indicates that the activated ultrafine fly ash plays a filling role in the grouting material, making it less prone to shrinkage.

[0062] As can be seen from Comparative Example 3, when ultrafine fly ash is replaced with 600-mesh fly ash, the setting time remains basically unchanged, but the compressive strength and expansion ratio are significantly lower than those of the example. This shows that finer fly ash has a significant effect on the compressive strength and expansion ratio of the grouting material.

[0063] Compared with Example 2, Comparative Example 4 is inferior to Example 2 in both setting time and compressive strength, especially in compressive strength, which decreased by 22%. Therefore, it can be concluded that the performance of urea-formaldehyde resin modified with melamine is significantly improved.

[0064] As can be seen from Comparative Example 5, when ethylene urea was replaced with water, the initial setting time was slightly prolonged compared to Example 3, and the strength at 0.5h, 1d, and 3d decreased by 16.8%, 22.3%, and 19.4%, respectively. This indicates that ethylene urea improved the crosslinking density of the resin through reaction or structural regulation, thereby improving the strength.

[0065] Comparative Examples 6 and 7 show that replacing activated ultrafine fly ash with talc or limestone powder significantly prolongs the setting time and markedly reduces the compressive strength (which decreased by 55.6% and 41.1% respectively at 3 days), failing to meet the basic physicochemical properties of standard AQ / T 1089-2020. This is because the carbonates in the added talc and limestone powder react with phosphoric acid to generate gas, causing the gas in the final solidified body to expand, resulting in decreased strength and increased porosity.

[0066] The data measured in Comparative Example 8 in Table 1 show that, compared with Example 1, the reaction temperature of Comparative Example 8 without added organic carboxylic acid esters increased significantly, that is, the reaction temperature stability was significantly reduced. The addition of organic carboxylic acid esters also had a beneficial effect on strength, solving the problems of reaction runaway and insufficient strength at low temperature.

[0067] The data measured in Comparative Example 9 in Table 1 show that: Example 2, compared to Comparative Example 9, adds a silane coupling agent to modify the activated ultrafine fly ash. Nano-silica can fill the tiny pores between the modified fly ash particles. The multi-level filling system of modified fly ash and nano-silica reduces the porosity. The compressive strength at 0.5h, 1d, and 3d is increased by 31.9%, 33.5%, and 21.4% respectively compared to the comparative example, significantly improving the density and durability of the solidified body.

[0068] The data measured in Comparative Example 10 in Table 1 show that: Compared with Comparative Example 10, Example 1 used activated ultrafine fly ash. After activating the ultrafine fly ash, the setting time was shortened and the reaction temperature was slightly increased. The compressive strength at 0.5h, 1d, and 3d was increased by 19.6%, 7.0%, and 3.8% respectively compared with the comparative example. This indicates that activating the ultrafine fly ash improved the reactivity of the fly ash, especially in the early stage.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-temperature dual-liquid reinforcement material for coal and rock masses, characterized in that, Includes component A and component B; By weight, component A comprises: 70-90 parts melamine-modified urea-formaldehyde resin, 5-10 parts ammonia, 0.2-0.6 parts emulsifier, 0.1-0.6 parts defoamer, 0.5-2 parts ethylene urea, 0.5-2 parts organic carboxylic acid ester, 0.3-0.9 parts nano silica, 0.2-1.2 parts silane coupling agent, and 5-15 parts activated ultrafine fly ash; wherein the organic carboxylic acid ester is tributyl citrate; and the ethylene urea is N-hydroxymethylethylene urea. The activated ultrafine fly ash is prepared by a method including the following steps: calcining ultrafine fly ash that can pass through a 1250-mesh sieve at 600℃ for 2 hours; By mass fractions, component B comprises: 20-50 parts phosphoric acid solution, 50-70 parts water, and 3-7 parts ammonium chloride; The mass ratio of component A to component B is (3-5):

1.

2. The low-temperature dual-liquid reinforcement material for coal and rock masses as described in claim 1, characterized in that, The melamine-modified urea-formaldehyde resin has a solid content of ≥50%.

3. The low-temperature dual-liquid reinforcement material for coal and rock masses as described in claim 1, characterized in that, The ultrafine fly ash has an alumina content of 25%-35%, a silica content of 55%-65%, and a calcium oxide content of 2%-8%.

4. The low-temperature dual-liquid reinforcement material for coal and rock masses as described in claim 1, characterized in that, The emulsifier is a polyoxyethylene ether emulsifier or a polyether emulsifier; The defoamer is an organosilicon defoamer or a polyether-modified silicone defoamer.

5. The low-temperature dual-liquid reinforcement material for coal and rock masses as described in claim 1, characterized in that, The concentration of the ammonia water is 20wt%-30wt%, and the product grade is superior.

6. The method for preparing the low-temperature dual-liquid reinforcement material for coal and rock masses as described in any one of claims 1-5, characterized in that, Includes the following steps: Preparation of Component A: The melamine-modified urea-formaldehyde resin was added to the first container, and ammonia, emulsifier, defoamer, silane coupling agent, organic carboxylic acid ester and ethylene urea were added in sequence while stirring. After stirring, the activated ultrafine fly ash and nano silica were added and dispersed at high speed to obtain Component A. Preparation of component B: The phosphoric acid solution is added to the second container, water and ammonium chloride are added, and the mixture is stirred to obtain component B.

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