Heavy-load highway flexible base self-repairing water-based polymer and preparation method thereof

Abstract

The application discloses a heavy-load highway flexible base self-repairing water-based polymer and a preparation method thereof, and belongs to the technical field of polymer materials. The polymer material comprises 2-amino-4-hydroxy-6-methyl pyrimidine modified isophorone diisocyanate prepolymer, 1-(3-aminopropyl)-3-methyl imidazole bromide, bisphenol A type water-based epoxy emulsion, isophorone diamine, modified nano silicon dioxide, silane coupling agent, deionized water, defoaming agent and rheological agent. The polymer material is hybridized with an ionic liquid by constructing a supramolecular network with dynamic hydrogen bonds, so that the unification of high permeability, high bonding strength and damage self-repairing function is realized. The polymer material has excellent mechanical properties, service life, permeability and environmental adaptability. Therefore, the application provides a high-performance and low-investment technical scheme for large-scale maintenance of heavy-load traffic and mine area roads.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a self-healing water-based polymer for flexible base courses of heavy-duty highways and its preparation method. Background Technology

[0002] Currently, flexible crushed stone base courses for heavy-duty highways, urban and rural roads and mining roads often face problems such as insufficient shear strength and the tendency to develop microcracks and permanent deformation under repeated heavy loads. Domestic projects of this type have long relied on imported materials, but they have the following significant disadvantages: (1) High cost and limited supply: The overall cost is much higher than that of domestic systems, and the supply cycle is uncertain due to international logistics, which limits large-scale application; (2) Closed technology system: Imported formulas are kept secret, making it difficult to adjust the performance according to the aggregate gradation, temperature and humidity and complex working conditions (such as the rainy mountainous environment in Chongqing and the low temperature and humid region in Guizhou) in different regions of China; (3) Contradiction between material brittleness and fatigue resistance: Although the existing domestic methacrylic resin-based reinforcement materials have high hardness, they are prone to brittle fatigue failure under repeated heavy loads and lack the ability to repair damage.

[0003] In summary, there is an urgent need to develop a self-healing water-based polymer suitable for the maintenance and reinforcement of heavy-duty roads using flexible crushed stone base courses. Summary of the Invention

[0004] To address the problems of existing technologies, the present invention aims to provide a self-healing water-based polymer for flexible base courses of heavy-duty highways and its preparation method, thereby solving the problems of uncontrollable costs of existing imported materials and the limited functionality and easy fatigue damage of domestically produced resins.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A self-healing water-based polymer for flexible base courses of heavy-duty highways is provided, comprising the following components in parts by weight: 30-50 parts of 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer, 5-15 parts of 1-(3-aminopropyl)-3-methylimidazolium bromide, 20-40 parts of bisphenol A type aqueous epoxy emulsion, 3-8 parts of isophorone diamine, 1-5 parts of modified nano-silica, 1-3 parts of silane coupling agent, 40-60 parts of deionized water, 0.5-2 parts of defoamer, and 0.5-2 parts of rheology modifier; Among them, the 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer has a polyurethane elastomer backbone, and its main chain has pyrimidinone units, which form dynamic crosslinks through quadruple hydrogen bond sites.

[0006] Furthermore, the solid content of the self-healing water-based polymer for heavy-duty highway flexible base courses is 45%-55%, and the viscosity is 50-200 mPa·s.

[0007] Furthermore, the modified nano-silica is nano-silica modified with KH-560; the silane coupling agent is KH-550.

[0008] Furthermore, the defoamer is a nonionic polyether-modified polysiloxane; the rheology modifier is a hydrophobically modified ethoxylated polyurethane.

[0009] This invention provides a method for preparing the above-mentioned self-healing water-based polymer for heavy-duty highway flexible base courses, comprising the following steps: (1) After mixing isophorone diisocyanate with polytetrahydrofuran ether diol, the mixture was reacted at 50-80℃ for 1-2h under an inert gas. Then, 2-amino-4-hydroxy-6-methylpyrimidine was added and the reaction was continued until the NCO content reached the theoretical design value, so as to obtain 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer. (2) Add 1-(3-aminopropyl)-3-methylimidazolium bromide to the 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer of step (1), and then stir the reaction for 40-60 min. (3) Add bisphenol A type aqueous epoxy emulsion to the product obtained in step (2), mix well, add 3-8 parts of isophorone diamine, continue stirring for 30-40 minutes, and then add 50-70℃ deionized water in batches using the phase inversion emulsification technology to obtain O / W type hybrid emulsion. (4) Add the modified nano-silica and silane coupling agent to the O / W hybrid emulsion obtained in step (3), and then sonicate for 20-30 min; (5) Add defoamer and rheology modifier to the product obtained in step (4) in sequence, mix well and sieve to obtain the product.

[0010] Furthermore, in step (1), the NCO / OH molar ratio of isophorone diisocyanate and polytetrahydrofuran ether diol is 1.2-1.5.

[0011] Furthermore, the theoretical design value of NCO content in step (1) is 0.75%~1.83%.

[0012] Furthermore, in step (3), the epoxy equivalent of the bisphenol A type aqueous epoxy emulsion is 190-210 g / eq.

[0013] Furthermore, in step (3), the rotation speed of the reverse emulsification technology is 2500-3000 rpm.

[0014] Furthermore, the power of the ultrasonic treatment in step (4) is 400-450W.

[0015] The present invention has the following beneficial effects: (1) This invention achieves a unified system of high permeability, high bonding strength, and self-repair function by constructing a supramolecular network with dynamic hydrogen bonds and an ionic liquid hybrid system. The functions of each component of the polymer in this invention are as follows: 2-Amino-4-hydroxy-6-methylpyrimidine modified prepolymer (main component): provides the polyurethane elastomer backbone, and the pyrimidinone (UPy) units contained therein can form dynamic crosslinks through quadruple hydrogen bonds, which is the core source of achieving self-healing function; 1-(3-aminopropyl)-3-methylimidazolium bromide (main component): As a functionalized ionic liquid, its amino terminus participates in polymer chain extension, and the imidazole ring provides high polarity. It can significantly reduce the surface tension of materials, enabling polymers to penetrate into the micron-sized gaps in the crushed stone substrate; Bisphenol A type waterborne epoxy emulsion (main component): After curing, it forms a dense three-dimensional network structure, providing the necessary shear strength and compressive modulus for flexible crushed stone base layer, and preventing permanent deformation under heavy load; Isophorone diamine (IPDA): As a crosslinking agent, it reacts with epoxy groups, and its alicyclic structure can improve the weather resistance and hardness of materials. KH-560 modified nano silica (minor component): as an inorganic reinforcing filler, it increases the cohesive strength of the material and forms physical / chemical crosslinking points with the organic phase; KH-550 (auxiliary component): enhances the chemical bonding between the polymer and crushed stone (mainly silicate aggregate), improving water-resistant peeling properties.

[0016] (2) The polymer of this invention exhibits excellent mechanical properties and service life: Through the "rigid-flexible" molecular design, this invention increases the shear strength of the crushed stone base layer by 42%-65%, which is much higher than the 20% of traditional materials. The most significant breakthrough is the introduction of self-healing function. Micro-cracks in the road surface caused by heavy loads can heal themselves within 24 hours, with a repair efficiency of over 85%, which greatly extends the fatigue life of the road.

[0017] (3) The polymer of this invention has significant advantages in terms of permeability and environmental adaptability: due to the addition of functionalized ionic liquid, the penetration depth of this material reaches 6.5-9.5cm, which is more than 3 times that of the prior art (about 2.1cm), and can completely solve the problems of shallow and uneven reinforcement. At the same time, it can still maintain more than 90% of the strength retention rate in humid environments, making it particularly suitable for complex working conditions in mountainous and rainy areas.

[0018] (4) This invention achieves a significant reduction in cost and technological independence. By replacing expensive series of chemical raw materials with domestically produced ones, the cost per unit material is reduced by 40% to 55%. This not only breaks the monopoly of foreign technology in the field of heavy-duty road reinforcement and ensures the stability of the supply chain, but also provides a high-performance, low-investment domestic solution for the large-scale maintenance of heavy-duty traffic and mining roads. Detailed Implementation

[0019] The principles and features of the present invention are described below with reference to embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, specific conditions or manufacturer-recommended conditions should be followed in the embodiments. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0020] Example 1: A self-healing water-based polymer for flexible base courses of heavy-duty highways comprises the following components in parts by weight: 40 parts of 2-amino-4-hydroxy-6-methylpyrimidine-modified isophorone diisocyanate prepolymer, 10 parts of 1-(3-aminopropyl)-3-methylimidazolium bromide ([Apmim]Br) (CAS 914770-45-9, Beijing Huawi Ruike Chemical), 30 parts of bisphenol A type waterborne epoxy emulsion (epoxy equivalent 190g / eq, Yoshida Chemical), 5 parts of isophorone diamine (IPDA, CAS 2855-13-2, Aladdin Reagent), 3 parts of KH-560 ((γ-glycidyl etheroxypropyltrimethoxysilane)) modified nano-silica (Shanghai Dewar Chemical), and 2 parts of γ-aminopropyltriethoxysilane (KH-550) (CAS 914770-45-9, Beijing Huawi Ruike Chemical). The ingredients are: 919-30-2 (Guangzhou Suixin Chemical), 50 parts deionized water, 1 part defoamer (nonionic polyether-modified polysiloxane, Dow Corning DC-65), and 1 part rheology modifier (hydrophobic-modified ethoxylated polyurethane, Wanhua Chemical WT-105A). The preparation method is as follows: (1) Supramolecular framework synthesis (dynamic hydrogen bond site implantation): Isophorone diisocyanate (IPDI) and polytetrahydrofuran ether diol (PTMG, molecular weight Mn=2000) were added to a reactor at an NCO / OH molar ratio of 1.2. Under nitrogen protection, the reaction was carried out at 80℃ for 2 h to obtain a polyurethane prepolymer. Then, 2-amino-4-hydroxy-6-methylpyrimidine was added as a chain extender, and the reaction was continued for 3 h until the NCO content reached 0.75%~1.83%, thus preparing a 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer with pyrimidinone (UPy) units in the main chain and four hydrogen bond sites.

[0021] (2) Ionic liquid chemical hybridization modification: The prepolymer obtained in step (1) was cooled to 60℃, and then 1-(3-aminopropyl)-3-methylimidazolium bromide ([Apmim]Br) was added. The mixture was stirred at 1000 rpm for 40 min. By utilizing the chemical bonding between the terminal amino group of the ionic liquid and the residual NCO group of the prepolymer, as well as the ionic dipole interaction between the imidazole ring and the polyurethane chain segment, the ionic liquid was uniformly implanted into the molecular chain, thereby reducing the surface tension of the system and pre-setting polarity enhancement sites.

[0022] (3) Construction of interpenetrating network (IPN) and phase inversion emulsification: Bisphenol A type aqueous epoxy emulsion was slowly added dropwise to the product obtained in step (2), and after mixing, 5 parts of IPDA were added and the shear emulsifier was turned on, with the speed increased to 2500 rpm. Deionized water preheated to 50°C was added slowly in batches. Phase inversion emulsification technology was used to transform the system from water-in-oil (W / O) to a stable oil-in-water (O / W) hybrid emulsion, forming a molecular network in which polyurethane and epoxy resin interpenetrate each other.

[0023] (4) Interfacial enhancement of nanophase in situ dispersion: KH-560 modified nano-silica and KH-550 were added to the emulsion to enhance interfacial activity. Then, an ultrasonic dispersion device was used to treat the emulsion at 400W power for 20 minutes to ensure that the nanoparticles were uniformly distributed in the emulsion and that no secondary agglomeration occurred.

[0024] (5) Comprehensive blending and finished product stabilization: Defoamer and rheology modifier are added to the emulsion in sequence and stirred evenly at low speed (300 rpm). The solid content is adjusted to 45%-55%, and the final system viscosity is controlled within the range of 50-200 mPa·s. After filtration through a 200-mesh filter, the finished product is obtained by filling.

[0025] The polymer in this embodiment adopts a standard heavy-duty balanced formulation, which is suitable for the graded crushed stone base course of conventional heavy-duty national and provincial highways, taking into account both strength enhancement and dynamic damage repair.

[0026] The finished product prepared in this embodiment was tested for key properties using the following methods: According to GB / T 16777-2008 standard, its solid content was measured to be 50.2% at 105℃; according to GB / T 2794-2013 standard, its viscosity was measured to be 125 mPa·s at 25℃; a pouring test was conducted using a crushed stone base penetration test column, and after curing, the penetration depth was measured to be 6.8 cm after being cut open; a coating sample was prepared according to GB / T 16777-2008 and pre-fabricated with microcracks. After static curing for 24 hours in an environment of 25℃ and 95% relative humidity, the self-healing efficiency was measured to be 86% through a tensile strength recovery rate test.

[0027] Example 2: A self-healing water-based polymer for flexible base courses of heavy-duty highways comprises the following components in parts by weight: 30 parts of 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer, 5 parts of [Apmim]Br (CAS 914770-45-9, Beijing Huawi Ruike Chemical), 40 parts of bisphenol A type waterborne epoxy emulsion (epoxy equivalent 200g / eq, Yoshida Chemical), 8 parts of IPDA (CAS 2855-13-2, Aladdin Reagent), 5 parts of KH-560 modified nano silica (Shanghai Dewar Chemical), 1.5 parts of KH-550 (CAS 919-30-2, Guangzhou Suixin Chemical), 42 parts of deionized water, 1.5 parts of defoamer (nonionic polyether modified polysiloxane, Dow Corning DC-65), and 1.5 parts of rheology modifier (hydrophobic modified ethoxylated polyurethane, Wanhua Chemical WT-105A). Its preparation method is as follows: (1) Supramolecular framework synthesis (dynamic hydrogen bond site implantation): Isophorone diisocyanate (IPDI) and polytetrahydrofuran ether diol (PTMG, molecular weight Mn=2000) were added to a reactor at an NCO / OH molar ratio of 1.5. Under nitrogen protection, the reaction was carried out at 50℃ for 2 h to obtain a polyurethane prepolymer. Then, 2-amino-4-hydroxy-6-methylpyrimidine was added as a chain extender, and the reaction was continued for 3 h until the NCO content reached 0.75%~1.83%, thus preparing a 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer with pyrimidinone (UPy) units in the main chain and four hydrogen bond sites.

[0028] (2) Ionic liquid chemical hybridization modification: The prepolymer obtained in step (1) was cooled to 60℃, and then 1-(3-aminopropyl)-3-methylimidazolium bromide ([Apmim]Br) was added. The mixture was stirred at 1000 rpm for 60 min. By utilizing the chemical bonding between the terminal amino group of the ionic liquid and the residual NCO group of the prepolymer, as well as the ionic dipole interaction between the imidazole ring and the polyurethane chain segment, the ionic liquid was uniformly implanted into the molecular chain, thereby reducing the surface tension of the system and pre-setting polarity enhancement sites.

[0029] (3) Construction of interpenetrating network (IPN) and phase inversion emulsification: Bisphenol A type aqueous epoxy emulsion was slowly added dropwise to the product obtained in step (2), and after mixing, 8 parts of IPDA were added and the shear emulsifier was turned on, with the speed increased to 2500 rpm. Deionized water preheated to 60°C was added slowly in batches. Using phase inversion emulsification technology, the system was transformed from water-in-oil (W / O) to a stable oil-in-water (O / W) hybrid emulsion, forming a molecular network in which polyurethane and epoxy resin interpenetrate each other.

[0030] (4) Interfacial enhancement of nanophase in situ dispersion: KH-560 modified nano-silica and KH-550 were added to the emulsion to enhance interfacial activity. Then, an ultrasonic dispersion device was used to treat the emulsion at 400W power for 30 minutes to ensure that the nanoparticles were uniformly distributed in the emulsion and that no secondary agglomeration occurred.

[0031] (5) Comprehensive blending and finished product stabilization: Defoamer and rheology modifier are added to the emulsion in sequence and stirred evenly at low speed (300 rpm). The solid content is adjusted to 45%-55%, and the final system viscosity is controlled within the range of 50-200 mPa·s. After filtration through a 200-mesh filter, the finished product is obtained by filling.

[0032] The polymer used in this embodiment is a high-rigidity formulation for extremely heavy-duty / mining roads. It is designed for the frequent rolling conditions caused by heavy vehicles in mining areas. The shear strength of the base layer is improved by increasing the proportion of epoxy resin skeleton.

[0033] The finished product prepared in this embodiment was tested for key properties using the following methods: its solid content was measured to be 54.5% at 105℃ according to GB / T 16777-2008 standard; its viscosity was measured to be 190 mPa·s at 25℃ according to GB / T 2794-2013; after standard specimens were prepared using the same crushed stone base material and reinforced, shear strength tests were conducted according to the test method for inorganic binder stabilized materials in highway engineering (JTG E51-2009). The shear strength of the reinforced specimens was increased by 62% compared to the unreinforced specimens, indicating that the material can significantly improve the shear resistance of the base structure and effectively suppress rutting deformation under heavy loads.

[0034] Example 3: A self-healing water-based polymer for flexible base courses of heavy-duty highways comprises the following components in parts by weight: 50 parts of 2-amino-4-hydroxy-6-methylpyrimidine-modified isophorone diisocyanate prepolymer, 15 parts of [Apmim]Br (CAS 914770-45-9, Beijing Huawi Ruike Chemical), 20 parts of bisphenol A type waterborne epoxy emulsion (epoxy equivalent 210 g / eq, Yoshida Chemical), 3 parts of IPDA (CAS 2855-13-2, Aladdin Reagent), 1.5 parts of KH-560 modified nano-silica (Shanghai Dewar Chemical), 3 parts of KH-550 (CAS 919-30-2, Guangzhou Suixin Chemical), 60 parts of deionized water, 2 parts of defoamer (nonionic polyether-modified polysiloxane, Dow Corning DC-65), and 2 parts of rheology modifier (hydrophobically modified ethoxylated polyurethane, Wanhua Chemical WT-105A). Its preparation method is as follows: (1) Supramolecular framework synthesis (dynamic hydrogen bond site implantation): Isophorone diisocyanate (IPDI) and polytetrahydrofuran ether diol (PTMG, molecular weight Mn=2000) were added to a reactor at an NCO / OH molar ratio of 1.5. Under nitrogen protection, the reaction was carried out at 70℃ for 1 h to obtain a polyurethane prepolymer. Then, 2-amino-4-hydroxy-6-methylpyrimidine was added as a chain extender, and the reaction was continued for 3 h until the NCO content reached 0.75%-1.83%, thus preparing a 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer with pyrimidinone (UPy) units in the main chain and four hydrogen bond sites.

[0035] (2) Ionic liquid chemical hybridization modification: The prepolymer obtained in step (1) was cooled to 60℃, and then 1-(3-aminopropyl)-3-methylimidazolium bromide ([Apmim]Br) was added. The mixture was stirred at 1000 rpm for 60 min. By utilizing the chemical bonding between the terminal amino group of the ionic liquid and the residual NCO group of the prepolymer, as well as the ionic dipole interaction between the imidazole ring and the polyurethane chain segment, the ionic liquid was uniformly implanted into the molecular chain, thereby reducing the surface tension of the system and pre-setting polarity enhancement sites.

[0036] (3) Construction of interpenetrating network (IPN) and phase inversion emulsification: Bisphenol A type aqueous epoxy emulsion was slowly added dropwise to the product obtained in step (2), and after mixing, 3 parts of IPDA were added and the shear emulsifier was turned on. The rotation speed was increased to 3000 rpm, and deionized water preheated to 70°C was slowly added in batches. Using phase inversion emulsification technology, the system was transformed from water-in-oil (W / O) to a stable oil-in-water (O / W) hybrid emulsion, forming a molecular network in which polyurethane and epoxy resin interpenetrate each other.

[0037] (4) Interfacial enhancement of nanophase in situ dispersion: KH-560 modified nano-silica and KH-550 were added to the emulsion to enhance interfacial activity. Then, an ultrasonic dispersion device was used to treat the emulsion at 450W power for 30 minutes to ensure that the nanoparticles were uniformly distributed in the emulsion and that no secondary agglomeration occurred.

[0038] (5) Comprehensive blending and finished product stabilization: Defoamer and rheology modifier are added to the emulsion in sequence and stirred evenly at low speed (300 rpm). The solid content is adjusted to 45%-55%, and the final system viscosity is controlled within the range of 50-200 mPa·s. After filtration through a 200-mesh filter, the finished product is obtained by filling.

[0039] The polymer in this embodiment adopts a high-permeability self-healing formula for mountainous and rainy environments. It is designed for humid mountain environments and dense crushed stone gradations, and utilizes a high proportion of ionic liquid to enhance permeability and hydrophilic adhesion.

[0040] The finished material prepared in this embodiment was tested for its key properties using the following methods: According to GB / T 2794-2022 standard, its viscosity was measured to be as low as 62 mPa·s at 25℃ using a rotational viscometer; after the material was poured into a test column of 5-10 mm graded damp crushed stone aggregate with a moisture content of 8% and cured, the penetration depth was measured to be up to 9.5 cm; a coating sample was prepared according to GB / T 16777-2008 and pre-fabricated with 0.1 mm microcracks. After curing in an environment of 25℃ and 95% relative humidity for 12 hours, the self-healing efficiency of the microcracks reached 91% through water tightness and tensile strength recovery rate tests.

[0041] Experimental Example: Characterization of Prepolymer Structure and Functionality To verify whether the 2-amino-4-hydroxy-6-methylpyrimidine-modified isophorone diisocyanate prepolymer prepared in step (1) of Examples 1-3 was successfully synthesized, the NCO content was determined using the method specified in GB / T 12009.4-2016 "Aromatic Isocyanates for Polyurethane Production - Part 4: Determination of Isocyanate Content", di-n-butylamine titration. Anhydrous toluene was used as the solvent, di-n-butylamine as the reaction reagent, and hydrochloric acid standard solution was used for back titration. Bromophenol blue was used as the indicator to quantitatively analyze the isocyanate (-NCO) content of the prepolymer sample. The specific operation steps are as follows: (1) Weigh 0.2g of the 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer prepared in step (1) of Examples 1-3, place it in a 250 mL stoppered conical flask, add 25 mL of anhydrous toluene, and gently shake to completely dissolve the sample, ensuring that there is no turbidity or insoluble matter; (2) Accurately add 10.00 mL of 0.1 mol / L di-n-butylamine-toluene solution to the conical flask using a pipette, tighten the stopper and shake well. Let it stand at room temperature for 30 min to allow the terminal -NCO groups in the prepolymer to react completely with di-n-butylamine to generate urea groups. (3) Add 50 mL of isopropanol (or anhydrous ethanol) to the solution after the reaction in step (2) for dilution, and then add 4 drops of bromophenol blue indicator. At this point, the solution will be blue. Then titrate with 0.1 mol / L hydrochloric acid standard solution, shaking while titrating. When the solution color changes abruptly from blue to yellow-green and does not fade within 30 seconds, this is the titration endpoint. Record the volume of hydrochloric acid consumed. At the same time, perform a blank test using the same steps (without adding the sample, and all other operations are exactly the same), and record the volume of hydrochloric acid consumed in the blank test.

[0042] (4) Calculate the NCO content according to the standard formula in GB / T 12009.4-2016:

[0043] In the formula: The volume (mL) of hydrochloric acid solution consumed for the blank test; The volume (mL) of hydrochloric acid solution consumed in the titration of the sample; 42.02 represents the concentration of the hydrochloric acid standard solution (mol / L); 42.02 represents the molar mass of the NCO group (g / mol). The mass (g) of the prepolymer sample.

[0044] After three parallel measurements, the average value was used to calculate that the NCO content of the 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer prepared in step (1) of Examples 1-3 was 1.21%, 1.37% and 1.33%, respectively, all within the target control range (0.75%~1.83%). This proves that the 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer prepared in this invention was successfully synthesized. The functionality of its terminal isocyanate group meets the design requirements, the reaction process is controllable, and there are no obvious side reactions that cause excessive consumption or excessive residue of NCO.

[0045] 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-healing water-based polymer for heavy-duty highway flexible base courses, characterized in that, The product comprises the following components in parts by weight: 30-50 parts of 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer, 5-15 parts of 1-(3-aminopropyl)-3-methylimidazolium bromide, 20-40 parts of bisphenol A type aqueous epoxy emulsion, 3-8 parts of isophorone diamine, 1-5 parts of modified nano silica, 1-3 parts of silane coupling agent, 40-60 parts of deionized water, 0.5-2 parts of defoamer, and 0.5-2 parts of rheology modifier; The 2-amino-4-hydroxy-6-methylpyrimidine-modified isophorone diisocyanate prepolymer has a polyurethane elastomer backbone, and its main chain contains pyrimidinone units, which form dynamic crosslinks through quadruple hydrogen bond sites.

2. The self-healing water-based polymer for heavy-duty highway flexible base course according to claim 1, characterized in that, The solid content of the self-healing water-based polymer for heavy-duty highway flexible base courses is 45%-55%, and the viscosity is 50-200 mPa·s.

3. The self-healing water-based polymer for heavy-duty highway flexible base course according to claim 1, characterized in that, The modified nano-silica is nano-silica modified with KH-560; the silane coupling agent is KH-550.

4. The self-healing water-based polymer for heavy-duty highway flexible base course according to claim 1, characterized in that, The defoamer is a nonionic polyether-modified polysiloxane; the rheology modifier is a hydrophobically modified ethoxylated polyurethane.

5. The method for preparing the self-healing water-based polymer for heavy-duty highway flexible base course according to any one of claims 1-4, characterized in that, Includes the following steps: (1) After mixing isophorone diisocyanate with polytetrahydrofuran ether diol, the mixture was reacted at 50-80℃ for 1-2h under an inert gas. Then, 2-amino-4-hydroxy-6-methylpyrimidine was added and the reaction was continued until the NCO content reached the theoretical design value, so as to obtain 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer. (2) Add 1-(3-aminopropyl)-3-methylimidazolium bromide to the 2-amino-4-hydroxy-6-methylpyrimidine modified isophorone diisocyanate prepolymer of step (1), and then stir the reaction for 40-60 min. (3) Add bisphenol A type aqueous epoxy emulsion to the product obtained in step (2), mix well, add 3-8 parts of isophorone diamine, continue stirring for 30-40 minutes, and then add 50-70℃ deionized water in batches using the phase inversion emulsification technology to obtain O / W type hybrid emulsion. (4) Add the modified nano-silica and silane coupling agent to the O / W hybrid emulsion obtained in step (3), and then sonicate for 20-30 min; (5) Add defoamer and rheology modifier to the product obtained in step (4) in sequence, mix well and sieve to obtain the product.

6. The preparation method according to claim 5, characterized in that, The NCO / OH molar ratio of isophorone diisocyanate and polytetrahydrofuran ether diol in step (1) is 1.2-1.

5.

7. The preparation method according to claim 5, characterized in that, The theoretical design value of NCO content mentioned in step (1) is 0.75%~1.83%.

8. The preparation method according to claim 5, characterized in that, The epoxy equivalent of the bisphenol A type aqueous epoxy emulsion mentioned in step (3) is 190-210 g / eq.

9. The preparation method according to claim 5, characterized in that, The rotation speed of the reverse emulsification technology described in step (3) is 2500-3000 rpm.

10. The preparation method according to claim 5, characterized in that, The power of the ultrasonic treatment in step (4) is 400-450W.

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