An environment-friendly polyurethane grouting material for plugging and a preparation method thereof

Abstract

This invention discloses an environmentally friendly polyurethane grouting material for leak sealing and its preparation method. The material includes: 1-10 parts of polymethylene polyphenyl isocyanate, 8-15 parts of toluene diisocyanate, 5-10 parts of polyether triol, 40-50 parts of polyether tetraol, 30-45 parts of composite solvent, and 0.01-0.05 parts of inorganic acid. The composite solvent is composed of raw materials in a mass ratio of dibutyl phthalate: dimethyl carbonate: dipropylene glycol dimethyl ether = 1:1:(1-1.5). The method includes: weighing the raw materials; mixing polymethylene polyphenyl isocyanate, toluene diisocyanate, and inorganic acid, stirring and heating to obtain mixture A; dehydrating polyether triol and polyether tetraol under vacuum and then cooling to obtain mixture B; adding mixture A to mixture B, reacting, and then adding the composite solvent to obtain the environmentally friendly polyurethane grouting material for leak sealing. The grouting material prepared by this method has both environmental protection and high water-binding properties, and the raw materials are environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of building waterproofing materials, and in particular to an environmentally friendly polyurethane grouting material for sealing leaks and its preparation method. Background Technology

[0002] Polyurethane materials are currently the most diverse, widely applicable, and widely used type of chemical grouting material. Generally, based on material properties, they can be divided into two types: hydrophilic (water-soluble) and hydrophobic (oil-soluble). Hydrophilic polyurethane grouting materials are mainly polymerized from polyisocyanates and high-molecular-weight, multifunctional hydrophilic polyether polyols. They are easily dispersed in water and self-emulsify upon contact with water; they have good hydrophilicity, high water retention, and undergo immediate polymerization upon contact with water; the solidified material has both elastic and expansive waterproofing functions. Hydrophobic polyurethane grouting materials are not hydrophilic; they foam upon contact with water, generating secondary pressure, allowing them to be injected into minute cracks. The resulting foam has a certain strength and is suitable for waterproofing and leak-stopping applications requiring reinforcement. Another classification method is by components, dividing them into single-component and two-component types. Single-component polyurethane grouting materials have the advantage of being easy to use, but in order to ensure a low viscosity, they usually use polyether polyols with two functions or relatively high molecular weight as raw materials. This determines that most single-component polyurethane grouting materials are flexible and elastic materials, while two-component polyurethane grouting materials can provide materials with high strength, but they need to be prepared before use, which is not very convenient.

[0003] In existing technologies, to improve the injectability of grouting materials and ensure their good hydrophilicity, hydrophilic polyurethane grouting materials are often diluted with water-soluble solvents such as acetone and methyl ethyl ketone (MEK), as exemplified by a polyurethane chemical grouting material and its preparation method (patent number CN101220203A). This material uses toluene diisocyanate or diphenylmethane diisocyanate as raw materials and acetone or cyclohexanone as solvents. The volatilization of these solvents poses a serious threat to the health of construction workers, especially in poorly ventilated areas such as subways, tunnels, and basements, where this problem becomes particularly challenging. Furthermore, acetone and MEK both have low flash points and are flammable liquids, causing numerous inconveniences in the production, storage, transportation, and construction of polyurethane grouting materials, and also posing potential fire hazards. On the other hand, the high volatility of acetone and MEK inevitably leads to shrinkage of the solidified body, easily causing "re-leakage," and the volatilization of acetone and MEK also pollutes the environment.

[0004] However, existing technologies also have the following shortcomings:

[0005] Traditional inorganic grouting materials and other water-based polyurethane grouting materials are generally suitable for still water environments, but they cannot effectively block water in environments with large inflow volumes and fast flow rates. Currently available grouting materials have poor water-binding performance and low water-binding capacity. Summary of the Invention

[0006] The purpose of this invention is to provide an environmentally friendly polyurethane grouting material for sealing leaks and its preparation method, which solves the problems that the solvents used in existing materials have poor environmental performance and are not suitable for still water environments, and cannot play a water-sealing role in environments with large inflow and fast water flow.

[0007] This invention is achieved by providing an environmentally friendly polyurethane grouting material for sealing leaks, wherein the grouting material comprises the following raw materials in parts by weight:

[0008] 1-10 parts of polymethylene polyphenyl isocyanate

[0009] Toluene diisocyanate (TDI) 8-15 parts

[0010] 5-10 parts of polyether triol

[0011] 40-50 parts of polyether tetraol

[0012] 30-45 parts of compound solvent

[0013] Inorganic acid 0.01-0.05 parts;

[0014] The composite solvent is composed of raw materials in a mass ratio of dibutyl phthalate: dimethyl carbonate: dipropylene glycol dimethyl ether = 1:1:(1-1.5).

[0015] The grouting material of this invention disperses, emulsifies, and foams upon contact with water, and immediately undergoes a chemical reaction. According to the ratio of polyether triol and polyether tetraol to polyisocyanate described in this invention, the content of -NCO groups in the grout is within an optimal range. At a temperature of 12℃-35℃, the grout is uniformly dispersed in water to form an emulsion. The free -NCO groups in the grout can react with water rapidly, resulting in a short gelation time and forming a good water-stopping effect. It is also an impermeable elastic gel-like solid with excellent water-stopping performance.

[0016] Compared to existing technologies, the grouting material of this invention is well-suited for environments with large water inflow and high water velocity, thus having a wide range of applications and high applicability. Simultaneously, as the grout is injected into the crack, it permeates around the crack (forming primary permeation) and then reacts. Upon contact with water, it forms an elastic solidified substance, while the free isocyanate groups release CO2 gas. With the help of gas pressure, the grout can be further forced into the voids of the structure, allowing the porous structure or stratum to be completely and densely filled. It exhibits the characteristics of secondary permeation, penetrating into concrete cracks to produce a large permeation radius and solidified volume, ultimately forming a large-volume solid with good impermeability and excellent water-blocking effect.

[0017] The solidified body formed by the reaction has good extensibility, good elasticity, impermeability, and low-temperature resistance, and permanently retains its original shape in water.

[0018] The solvent used in the grouting material of this invention is environmentally friendly and environmentally friendly.

[0019] A further technical solution of the present invention is that the NCO% of the synthesized product in the present invention is 5%-7%.

[0020] The solidified form of this material upon contact with water not only possesses excellent water-stopping properties, but is also harmless and non-toxic to the human body and causes no pollution to the environment.

[0021] A further technical solution of the present invention is that the grouting material comprises the following raw materials in parts by weight:

[0022] 1-5 parts of polymethylene polyphenyl isocyanate

[0023] 8-10 parts of toluene diisocyanate (TDI)

[0024] 5-8 parts of polyether triol

[0025] 40-45 parts of polyether tetraol

[0026] 35-45 parts of compound solvent

[0027] Inorganic acid 0.01-0.04 parts;

[0028] The composite solvent is composed of raw materials in a mass ratio of dibutyl phthalate: dimethyl carbonate: dipropylene glycol dimethyl ether = 1:1:(1-1.4).

[0029] A further technical solution of the present invention is that the grouting material comprises the following raw materials in parts by weight:

[0030] 1.58 parts of polymethylene polyphenyl isocyanate

[0031] Toluene diisocyanate (TDI) 8.88 parts

[0032] 4.93 parts of polyether triol

[0033] 44.39 parts of polyether tetraol

[0034] 40.21 parts of composite solvent

[0035] 0.02 parts of inorganic acid;

[0036] The composite solvent is composed of raw materials in a mass ratio of dibutyl phthalate: dimethyl carbonate: dipropylene glycol dimethyl ether = 1:1:1.33.

[0037] A further technical solution of the present invention is that the inorganic acid is phosphoric acid with a concentration of 85%.

[0038] A further technical solution of the present invention is that the isocyanate content of the polymethylene polyphenyl isocyanate is 30.5% to 32%, and the viscosity at 25°C is 150 mPa·s to 250 mPa·s. PAPI has high reactivity, low vapor pressure, low volatility, and low harm to the human body, providing good rigidity for the material.

[0039] A further technical solution of the present invention is that the isocyanate content of the toluene diisocyanate is 48% to 48.2%, and the viscosity at 25°C is 3 mPa·s to 4 mPa·s. The TDI isocyanate content is 48% to 48.2%, and the viscosity is low, providing the material with good flexibility and elongation.

[0040] A further technical solution of the present invention is that the polyether tetraol has a molecular weight of 7000-8000 and a functionality of 3.5-4.5.

[0041] The polyether tetraol has strong hydrophilicity and high functionality, which gives the material good dispersibility and water-binding properties in water.

[0042] A further technical solution of the present invention is: the polyether triol has a molecular weight of 4500 and a functionality of 2.8-3.5.

[0043] The polyether triol has a relatively small molecular weight and high functionality, which provides the material with a certain strength.

[0044] This invention also provides a method for preparing an environmentally friendly polyurethane grouting material for leak sealing, wherein the grouting material is the environmentally friendly grouting material, and the preparation method includes the following steps:

[0045] Step 1: Weigh out the raw materials according to the corresponding proportions and set aside;

[0046] Step 2: Mix polymethylene polyphenyl isocyanate, toluene diisocyanate and inorganic acid in a certain proportion, stir and heat to 40℃-50℃ to obtain mixture A, which is set aside; dehydrate polyether triol and polyether tetraol under vacuum at 100℃-120℃ for 1.5-2 hours, and then cool to 40℃-50℃ to obtain mixture B;

[0047] Step 3: Add mixture A to mixture B in batches, heat to 80℃-85℃ and react for 2-2.5 hours. After adding the composite solvent, the environmentally friendly polyurethane grouting material for sealing is obtained. Store in a sealed container.

[0048] All reagents used in this invention are environmentally friendly, reducing pollution to human health, water quality, and the surrounding environment during production and use. They have good safety and environmental protection properties and do not pollute the environment. At the same time, the water-binding capacity of the grouting material is up to 25 times, and the grouting material combines environmental protection and high water-binding capacity.

[0049] Polymethylene polyphenyl isocyanate (PAPI): It is the main reaction raw material for polyurethane products. PAPI is a crude MDI, and the MDI content is usually around 50%. Because the vapor pressure of MDI is much lower than that of TDI, it is less harmful to the human body under normal and well-ventilated conditions.

[0050] Toluene diisocyanate (TDI): It is the main reactant for polyurethane products. It reacts with water to produce carbon dioxide, readily reacts with compounds containing active hydrogen atoms, and reacts with diols to form linear polyurethane or polyurethane resins.

[0051] Polyether polyols are the main reaction materials for polyurethane products. Compared with polyester polyols, polyurethane products synthesized from polyether polyols have better water resistance and low-temperature resistance.

[0052] Composite solvents can reduce the hardness of polyurethane products, improve their plasticity (ductility), and reduce foam brittleness. The composite solvents used in this invention are all environmentally friendly and do not pollute the environment. The resulting material, when exposed to water, forms a solidified body that not only has excellent water-stopping properties but is also harmless, non-toxic, and environmentally friendly.

[0053] Phosphoric acid: Phosphoric acid is inexpensive, non-volatile, and can suppress the side reactions of isocyanates.

[0054] In this invention, TDI and PAPI together provide the -NCO groups required by the system, and polyether triol and polyether tetraol together provide the -OH groups required by the system. The content of -NCO groups in this invention is within an optimal range, so that the material can form a good water-binding effect after reacting with water.

[0055] The raw materials of this invention are formulated into grouting material according to the above proportions, resulting in a polyurethane grouting material with low viscosity, high water content, and environmental friendliness.

[0056] The beneficial effects of this invention are as follows: The polyether triol and polyether tetraol in this invention are highly hydrophilic polyols with excellent compatibility with water, and their functionality ranges from 3 to 4. The higher the functionality, the better the water-binding performance. These two factors determine the high water-binding performance of the material. When the polyether triol and polyether tetraol are combined with polymethylene polyphenyl isocyanate and toluene diisocyanate, within the dosage range described in this invention, the content of -NCO groups after the reaction is in an optimal range. After the material reacts with water, it can have the best water-binding effect, so that the water-binding capacity of the material in this invention can reach up to 25 times when combined with water.

[0057] The grouting material of this invention disperses, emulsifies, and foams upon contact with water, and immediately undergoes a chemical reaction. According to the ratio of polyether triol and polyether tetraol to polyisocyanate described in this invention, the content of -NCO groups in the grout is within an optimal range. At a temperature of 12℃-35℃, the grout is uniformly dispersed in water to form an emulsion. The free -NCO groups in the grout can react with water quickly, resulting in a short gelation time and forming a good water-stopping effect. It is also an impermeable elastic gel-like solid that not only has good water-stopping performance but is also harmless and non-toxic to the human body and does not pollute the environment.

[0058] Compared with existing technologies, the grouting material of this invention is well-suited for environments with large water inflow and high water velocity, thus having a wide range of applications and high applicability. Simultaneously, when the grout is injected into the crack, it permeates around the crack (forming primary permeation) and then reacts. While reacting with water to form an elastic solidified substance, the free isocyanate groups release CO2 gas upon contact with water. With the help of gas pressure, the grout can be further forced into the voids of the structure, so that the porous structure or stratum can be completely filled and compacted. It has the characteristics of secondary permeation, and the permeation into the concrete crack produces a large permeation radius and solidified volume, resulting in a solidified body with large volume, good impermeability, and excellent water-blocking effect.

[0059] The solidified body formed by the reaction has good extensibility, good elasticity, impermeability, and low-temperature resistance, and permanently maintains its original shape in water;

[0060] All reagents used in this invention are environmentally friendly, reducing pollution to human health, water quality, and the surrounding environment during production and use. They have good safety and environmental protection properties and do not pollute the environment. At the same time, the water-binding capacity of the grouting material is up to 25 times, and the grouting material combines environmental protection and high water-binding capacity. Attached Figure Description

[0061] Figure 1 This is the environmental performance test report of the polyurethane grouting material corresponding to Example 2 provided by the present invention. Detailed Implementation

[0062] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0063] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0064] Example 1:

[0065] As shown in Table 1, the formulation of the environmentally friendly polyurethane grouting material for sealing leaks in this embodiment is as follows: The grouting material includes, by mass, 1.65 parts of polymethylene polyphenyl isocyanate (PAPI, in which -NCO content is 31% and viscosity at 25°C is 200 mPa·s), 9.27 parts of toluene diisocyanate (TDI-80), 5.15 parts of polyether triol, 46.34 parts of polyether tetraol, 37.58 parts of composite solvent (composed of dibutyl phthalate: dimethyl carbonate: dipropylene glycol dimethyl ether in a mass ratio of 1:1:1.33), and 0.02 parts of inorganic acid.

[0066] Example 2:

[0067] As shown in Table 1, the formulation of the environmentally friendly polyurethane grouting material for sealing leaks in this embodiment is as follows: The grouting material includes, by mass, 1.58 parts of polymethylene polyphenyl isocyanate (PAPI, in which the -NCO content is 31% and the viscosity at 25°C is 200 mPa·s), 8.88 parts of toluene diisocyanate (TDI-80), 4.93 parts of polyether triol, 44.39 parts of polyether tetraol, 40.2 parts of composite solvent (composed of dibutyl phthalate: dimethyl carbonate: dipropylene glycol dimethyl ether in a mass ratio of 1:1:1.33), and 0.02 parts of inorganic acid.

[0068] The mass fractions of each raw material in the environmentally friendly polyurethane grouting material used for leak sealing in Examples 1 and 2 are shown in Table 1 below.

[0069] Table 1 shows the mass fractions of each raw material in Examples 1 and 2.

[0070]

[0071]

[0072] Example 3:

[0073] The grouting material preparation and construction methods in Examples 1-2 above

[0074] Preparation method:

[0075] 1) Weigh out the corresponding mass parts of polymethylene polyphenyl isocyanate, toluene diisocyanate, polyether triol, polyether tetraol, and inorganic acid according to the mass ratio of each component raw material.

[0076] 2) Mix polymethylene polyphenyl isocyanate, toluene diisocyanate and inorganic acid in proportion, stir and heat to 45°C for later use; dehydrate polyether triol and polyether tetraol under high temperature vacuum at 100°C-120°C for 2 hours, then cool to 45°C, and then add the isocyanate mixture dropwise to the polyether mixture in batches, heat to 85°C and react for 2.5 hours, then add composite solvent to obtain the environmentally friendly polyurethane grouting material for sealing leaks, and store in a sealed container;

[0077] Construction method:

[0078] 3) During on-site construction, first treat the joint surface, remove surface dirt, ensure the joint surface is clean, and check the direction, depth and other conditions of the crack;

[0079] 4) Set up grouting holes by drilling inclined holes (45°) on both sides of the crack with a hole spacing of 20-30cm. In this embodiment, the hole spacing is 25cm to ensure that the grout can effectively penetrate into the crack or gap. Use compressed air to blow away the debris in the hole.

[0080] 5) Bury the pipe and seal the joint. Use a sealant or epoxy putty to bury the grouting pipe (box) and seal the joint surface at the same time.

[0081] 6) Clean the seams: Press water to rinse the seam surface, check the interconnection between the holes, and check the sealing effect at the same time;

[0082] 7) Pressure grouting: Grouting is performed under pressure. The grouting pressure is determined according to design requirements, ranging from 0.2MPa to 0.4MPa. The maximum pressure should not exceed the allowable value of the structure. In this embodiment, the pressure is 0.3MPa. Vertical joints are grouted from the lowest point upwards; horizontal joints are grouted from one end to the other. When pure grout appears in adjacent holes, grouting is suspended and the pipeline is tied. The grouting pipe is moved to the adjacent hole to continue grouting at the specified pressure until the grouting completion standard is met.

[0083] 8) After the grout has solidified, remove the grouting pipe and seal it with sealant or epoxy putty.

[0084] Comparative Example 1:

[0085] The LW water-soluble polyurethane (water-soluble type) developed by East China Survey and Design Institute includes the following raw materials: 1. Toluene diisocyanate (TDI); 2. Ethylene oxide-propylene oxide coether: The hydrophilicity of the polyoxyethylene segment and the hydrophobicity of the polyoxypropylene segment give this polyether a wide range of surface activities, resulting in a variety of products ranging from oil-soluble to water-soluble.

[0086] Performance testing:

[0087] The environmentally friendly polyurethane grouting materials for leak sealing prepared using the method of Example 3 in Comparative Example 1 and Examples 1 and 2 were tested, and the main performance parameters are shown in Table 2.

[0088] Table 2 Main Performance of Environmentally Friendly Polyurethane Grouting Materials for Leak Sealing

[0089]

[0090] As shown in Table 2, the grouting material obtained in Example 1 has a short gel time, low viscosity, and high solid content. The water-binding capacity of the grout can reach up to 25 times. Upon contact with water, it reacts immediately to form a large-volume, impermeable, and highly effective waterproof elastic gel-like solid, exhibiting excellent water-stopping properties. The grouting material obtained in Example 2 also has a short gel time, low viscosity, and high solid content, with a water-binding capacity of up to 25 times.

[0091] As shown in Table 2, the performance indicators of the environmentally friendly polyurethane grouting materials used for leak sealing in Examples 1-2 all meet the requirements for WPU products in "Polyurethane Grouting Materials" (JC / T2041-2020). The environmentally friendly polyurethane grouting materials used in Examples 1-2 achieve excellent results with short gel time, relatively low viscosity, large water-binding capacity, and high solids content. They can maximally meet the seepage prevention and leak sealing requirements of various engineering projects, such as expansion joints, cracks, sealing water inflow, and preventing water flow in the foundation. Their superior water-binding performance allows them to effectively seal water in environments with large inflow volumes and high flow rates.

[0092] The environmental performance of the environmentally friendly polyurethane grouting material used for leak sealing in Example 2 of Example 3 was tested, and the environmental performance test report is as follows: Figure 1 As shown in the test report, the grouting material described in Example 2 is non-toxic and environmentally friendly when used.

[0093] The environmentally friendly polyurethane grouting material for leak sealing prepared by this invention has low viscosity and good injectability when mixed with water. The solidified body is harmless, non-toxic, and non-polluting to the human body when immersed in water. Upon contact with water, it disperses, emulsifies, and foams on its own, immediately undergoing a chemical reaction to form a waterproof, elastic, gel-like solidified body with excellent water-stopping properties. The elastic, gel-like solidified body formed after the reaction has good extensibility, elasticity, impermeability, and low-temperature resistance, and permanently maintains its original shape in water.

[0094] The grouting material of this invention, compared to ordinary grouting liquids, will not be washed away by water; instead, the solidification area expands due to water flow, and its water-holding capacity is 25 times greater. When the grout is injected into the crack, it permeates around the crack (forming primary permeation), and then reacts, foaming and expanding to produce secondary permeation. This permeates into the concrete gaps, creating a large permeation radius and solidification volume, ultimately forming a large-volume solid with excellent impermeability and water-stopping effect. It exhibits high chemical stability, resistance to acids, alkalis, salts, and organic solvents, a smooth, wear-resistant surface that does not grow mold, and good durability of the solidified body.

[0095] The grouting material prepared by this invention reacts with water to form an elastic solidified substance while releasing CO2 gas. Utilizing the gas pressure, the grout can be further forced into the voids of the structure, allowing porous structures or strata to be completely and densely filled. It exhibits the characteristic of secondary infiltration. The grouting material has a large water-binding capacity, good hydrophilicity and injectability, and the viscosity and curing speed of the grout can be adjusted as needed. This invention improves the water-binding capacity of the grout, eliminating the drawback of low water-binding capacity in traditional grouts. It solves current application defects and expands the application fields of polyurethane.

[0096] All reagents used in this invention are environmentally friendly, reducing pollution to human health, water quality, and the surrounding environment during production and use. They exhibit good safety and environmental friendliness, causing no pollution. Furthermore, the grouting material boasts a water-binding capacity of up to 25 times, combining environmental friendliness with high water-binding performance. This invention's environmentally friendly polyurethane grouting material for leak sealing achieves an excellent gel time of 15-40 seconds and a water-binding capacity of 25 times.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An environmentally friendly polyurethane grouting material for leak sealing, characterized in that: The grouting material comprises the following raw materials in parts by weight: 1-10 parts of polymethylene polyphenyl isocyanate 8-15 parts of toluene diisocyanate 5-10 parts of polyether triol 40-50 parts of polyether tetraol 30-45 parts of compound solvent Inorganic acid 0.01-0.05 parts; The composite solvent is composed of raw materials in a mass ratio of dibutyl phthalate: dimethyl carbonate: dipropylene glycol dimethyl ether = 1:1:(1-1.5); the polymethylene polyphenyl isocyanate has an isocyanate content of 30.5% to 32% and a viscosity of 150 mPa•s to 250 mPa•s at 25°C; the toluene diisocyanate has an isocyanate content of 48% to 48.2% and a viscosity of 3 mPa•s to 4 mPa•s at 25°C; the polyether tetraol has a molecular weight of 7000-8000 and a functionality of 3.5-4.5; the polyether triol has a molecular weight of 4500 and a functionality of 2.8-3.

5.

2. The environmentally friendly polyurethane grouting material for leak sealing according to claim 1, characterized in that, The grouting material comprises the following raw materials in parts by weight: 1-5 parts of polymethylene polyphenyl isocyanate 8-10 parts of toluene diisocyanate 5-8 parts of polyether triol 40-45 parts of polyether tetraol 35-45 parts of compound solvent Inorganic acid 0.01-0.04 parts; The composite solvent is composed of raw materials in a mass ratio of dibutyl phthalate: dimethyl carbonate: dipropylene glycol dimethyl ether = 1:1:(1-1.4).

3. The environmentally friendly polyurethane grouting material for leak sealing according to claim 1, characterized in that, The grouting material comprises the following raw materials in parts by weight: 1.58 parts of polymethylene polyphenyl isocyanate 8.88 parts of toluene diisocyanate 4.93 parts of polyether triol 44.39 parts of polyether tetraol 40.21 parts of composite solvent 0.02 parts of inorganic acid; The composite solvent is composed of raw materials in a mass ratio of dibutyl phthalate: dimethyl carbonate: dipropylene glycol dimethyl ether = 1:1:1.

33.

4. The environmentally friendly polyurethane grouting material for leak sealing according to claim 1, characterized in that, The inorganic acid is phosphoric acid with a concentration of 85%.

5. A method for preparing an environmentally friendly polyurethane grouting material for leak sealing, wherein the grouting material is any one of the environmentally friendly polyurethane grouting materials for leak sealing according to claims 1-4, characterized in that, The preparation method includes the following steps: Step 1: Weigh out the raw materials according to the corresponding proportions and set aside; Step 2: Mix polymethylene polyphenyl isocyanate, toluene diisocyanate and inorganic acid in a certain proportion, stir and heat to 40℃-50℃ to obtain mixture A, which is set aside; dehydrate polyether triol and polyether tetraol under vacuum at 100℃-120℃ for 1.5-2 hours, and then cool to 40℃-50℃ to obtain mixture B; Step 3: Add mixture A to mixture B in batches, heat to 80℃-85℃ and react for 2-2.5 hours. After adding the composite solvent, the environmentally friendly polyurethane grouting material for sealing is obtained. Store in a sealed container.

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