A fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds and its preparation method

Abstract

This invention discloses a fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds and its preparation method, belonging to the field of modified asphalt technology. The raw materials are as follows (parts by weight): 100 parts base asphalt, 2-8 parts reversible crosslinking polyurethane modifier, and 1-2 parts compatibilizer. The preparation includes the following steps: heating the base asphalt to 130-140℃ to melt and stir; then adding the compatibilizer and reversible crosslinking polyurethane modifier to the molten base asphalt; maintaining the temperature and shearing at a shear rate of 1500 rpm for 30 minutes; then curing in an oven at 50-60℃ for 4-6 hours; and finally cooling to room temperature to obtain the fast-dissolving, high-viscosity modified asphalt. This invention modifies the base asphalt using a reversible crosslinking polyurethane modifier, resulting in modified asphalt with fast-dissolving and high-viscosity characteristics, significantly superior to traditional asphalt pavement performance. It also exhibits good reprocessing properties, enabling recycling and demonstrating extremely high circular economy value.

Description

Technical Field

[0001] This invention belongs to the field of modified asphalt technology, specifically relating to a fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds and its preparation method. Background Technology

[0002] Asphalt, with its relatively low cost and good mechanical properties, is currently widely used in road engineering. With the continuous increase in traffic volume and load, higher demands are being placed on the performance of asphalt pavement materials. During its service life, asphalt pavements are often subjected to repeated loads from vehicle wheels and the influence of natural conditions (heat, oxygen, rainwater), making them prone to problems such as rutting, potholes, and cracking, seriously affecting the comfort and safety of road driving. Therefore, it is necessary to modify asphalt to improve its road performance.

[0003] Polyurethane possesses excellent elasticity, wear resistance, and weather resistance, which can improve the crack resistance, durability, and weather resistance of asphalt materials, thereby enhancing pavement performance and extending service life. Based on the physical properties of modified asphalt, the commonly used polyurethane modifiers in polyurethane-modified asphalt are thermosetting. These thermosetting polyurethane modifiers form a network structure through chemical cross-linking and curing. This chemically cross-linked network structure not only affects the high-temperature melting and effective viscosity reduction of the base asphalt but also exhibits irreversibility. This means that the recycling of thermosetting polyurethane-modified asphalt requires high temperatures, or even makes effective recycling impossible, leading to the accumulation of waste materials and significantly reducing its circular economy value. Summary of the Invention

[0004] The purpose of this invention is to provide a fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds and its preparation method. By adding a reversible crosslinking polyurethane modifier, a three-dimensional network structure formed by crosslinking is introduced into the base asphalt, which improves the low-temperature toughness and viscosity of the modified asphalt. Moreover, under high-temperature conditions, the dynamic bonds in the reversible crosslinking polyurethane modifier break, which improves the fast-dissolving performance and reprocessability of the modified asphalt, thus solving the technical problems mentioned in the background art.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds comprises the following raw materials in parts by weight: 100 parts of base asphalt, 2-8 parts of reversible crosslinking polyurethane modifier, and 1-2 parts of compatibilizer.

[0007] The reversible crosslinking polyurethane modifier is prepared by the following steps:

[0008] Polytetrahydrofuran was heated to 100°C and melted under vacuum for 2 hours to remove moisture. After cooling to 60°C, a mixed solution of dibutyltin dilaurate and N,N-dimethylformamide was added dropwise, followed by the slow addition of hexamethylene diisocyanate. After the addition was complete, the mixture was stirred at 60°C under nitrogen protection for 4-6 hours to obtain a prepolymer solution. A chain extender and a reversible crosslinking agent were added to the prepolymer solution, and the mixture was reacted at 45°C for 18-24 hours. After vacuum drying, a reversible crosslinked polyurethane modifier was obtained. Polymerization was carried out using polytetrahydrofuran as the soft segment and hexamethylene diisocyanate as the hard segment under N,N-dimethylformamide as the solvent and dibutyltin dilaurate as the catalyst, to obtain an isocyanate-terminated prepolymer. Further chain extension and crosslinking were then performed to obtain a polyurethane modifier containing reversible dynamic carbon-carbon covalent bonds as crosslinking points.

[0009] Furthermore, the ratio of the polytetrahydrofuran, dibutyltin dilaurate, N,N-dimethylformamide and hexamethylene diisocyanate, chain extender and reversible crosslinking agent is 10g:0.05g:100mL:1.8-2g:0.5-1g:1.82-3.03g.

[0010] Furthermore, the molecular weight of the polytetrahydrofuran is 1800-2000 g / mol. Reversible crosslinking polyurethane modifiers prepared within this molecular weight range have excellent mechanical properties and stability. However, excessively large molecular weights will affect the processing performance of the modified asphalt.

[0011] Furthermore, the chain extender is 4-(4'-hydroxyphenyl)-2,3-diazanaphthalene-1-one. The two active hydrogens on 4-(4'-hydroxyphenyl)-2,3-diazanaphthalene-1-one can react with the isocyanate groups in the prepolymer, acting as a chain extender for the reversible crosslinked polyurethane modifier. This introduces a distorted, non-coplanar diazanaphthalene-biphenyl structure into the polyurethane molecular backbone, which not only improves the thermal stability and mechanical properties of the reversible crosslinked polyurethane modifier but also enhances its solubility in the base asphalt.

[0012] Furthermore, the reversible crosslinking agent is prepared through the following steps:

[0013] Step A1: Add 4,4"-dihydroxybenzophenone and anhydrous potassium carbonate to N,N-dimethylformamide and stir to mix. Then add 2-bromoethanol dropwise. Under nitrogen protection and at 90°C, stir and react for 24 hours. After cooling to room temperature, filter to remove anhydrous potassium carbonate. Add deionized water to the filtrate for precipitation. After vacuum filtration, freeze-dry the precipitate to obtain the intermediate. The hydroxyl group of 4,4"-dihydroxybenzophenone undergoes a substitution reaction with 2-bromoethanol, thereby forming an ether bond in the structure of the intermediate.

[0014] Step A2: The intermediate was added to N,N-dimethylformamide and stirred to dissolve. Then, isopropanol and acetic acid were added and mixed thoroughly. The mixture was then exposed to ultraviolet light for 4-6 days. After precipitation, the mixture was poured into deionized water and purified by silica gel column chromatography eluted with petroleum ether and ethyl acetate at a 1:1 volume ratio to obtain the reversible crosslinking agent. Under ultraviolet light irradiation and with acetic acid as a catalyst, the carbonyl group in the intermediate captured hydrogen atoms from isopropanol to form a hydroxyl group, which then underwent dimerization to synthesize a reversible crosslinking agent containing both a benzylpinacol structure and an ether bond.

[0015] Furthermore, the ratio of the amounts of 4,4"-dihydroxybenzophenone, anhydrous potassium carbonate, N,N-dimethylformamide and 2-bromoethanol is 8.5-8.6g: 11-12g: 20-30mL: 11.3-12.5g.

[0016] Furthermore, the ratio of the intermediate, N,N-dimethylformamide, isopropanol, and acetic acid is 6g:20mL:30-50mL:0.1mL.

[0017] Furthermore, the wavelength of the ultraviolet light is 350-395 nm, and the irradiance is 4-6 mW / cm². 3 .

[0018] Furthermore, the compatibilizer is octylphenol polyoxyethylene ether. Octylphenol polyoxyethylene ether has good solubility and dispersibility, and can effectively improve the compatibility between reversible crosslinked polyurethane and base asphalt, thereby improving the processing performance, compatibility, and stability of the modified asphalt.

[0019] A method for preparing fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds includes the following steps:

[0020] The base asphalt is heated to 130-140℃ and stirred until melted. Then, the compatibilizer and reversible crosslinking polyurethane modifier are added to the molten base asphalt. The temperature is maintained and sheared at a shear rate of 1500 rpm for 30 minutes, so that the reversible crosslinking polyurethane modifier is decrosslinked in the base asphalt and uniformly dispersed in the base asphalt. Then, it is placed in an oven at 50-60℃ for curing for 4-6 hours. At low temperature, the reversible crosslinking polyurethane modifier reorganizes into a crosslinked network structure. After cooling to room temperature, fast-dissolving high-viscosity modified asphalt is obtained.

[0021] Beneficial effects:

[0022] The reversible crosslinking agent prepared by this invention contains a benzinolide structure in its molecule, with ether bonds and hydroxyl groups connected around the benzinolide structure as the center. The benzinolide structure has excellent chemical stability and mechanical properties at room temperature, but under heating conditions, the carbon-carbon bond at its center can be broken to form a diphenylmethanol structure containing free radicals. During the cooling process, the two diphenylmethanol structures containing free radicals can recombine to restore the original benzinolide structure, making the crosslinking agent thermally reversible. At the same time, the ether bonds in the reversible crosslinking agent, in combination with the benzinolide structure, can improve the flexibility and stability of the reversible crosslinking agent.

[0023] This invention uses polytetrahydrofuran and hexamethylene diisocyanate as raw materials to synthesize an isocyanate-terminated prepolymer. Then, it is chain-extended and cross-linked using 4-(4'-hydroxyphenyl)-2,3-diazanaphth-1-one and a reversible cross-linking agent, simultaneously introducing the diazanaphthyl biphenyl structure and the benzinolide structure into the polyurethane molecule, thus obtaining a reversibly cross-linked polyurethane modifier with a cross-linked network structure. Through the synergistic effect of the diazanaphthyl biphenyl structure and the benzinolide structure, the obtained polyurethane modifier not only exhibits reversible cross-linking but also possesses excellent toughness, stability, and solubility.

[0024] This invention modifies a reversible crosslinked polyurethane modifier by warm-mixing it with a base asphalt. On one hand, at the melting temperature of the base asphalt, the crosslinking points of the benzidine alcohol structure in the reversible crosslinked polyurethane modifier break down, transforming it from a network polymer into a low-viscosity linear polymer. Under high-speed shear, it disperses uniformly with the base asphalt, exhibiting good compatibility. Furthermore, the presence of diazanaphthalene biphenyl structures in the linear structure enhances the rapid solubility of the reversible crosslinked polyurethane modifier in the base asphalt, achieving uniform dispersion in a short time. On the other hand, after cooling, these linear polymers recombine in the base asphalt, reforming into polymers with a stable network structure, uniformly distributed within the base asphalt matrix. This significantly improves the modified asphalt's penetration, softening point, ductility, and viscosity, resulting in high-viscosity modified asphalt with significantly superior pavement performance compared to traditional asphalt. More importantly, the modification of the base asphalt by the reversible crosslinked polyurethane modifier endows the modified asphalt with excellent reprocessing properties, enabling recycling at lower temperatures and enhancing its circular economy value. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] This embodiment provides a reversible crosslinking agent, which is prepared through the following steps:

[0028] Step A1: Add 8.5g of 4,4"-dihydroxybenzophenone and 11g of anhydrous potassium carbonate to 20mL of N,N-dimethylformamide and stir to mix. Then add 11.3g of 2-bromoethanol dropwise. Stir and react for 24h under nitrogen protection and at 90℃. After cooling to room temperature, filter. Add deionized water to the filtrate to precipitate. After vacuum filtration, freeze-dry the precipitate to obtain the intermediate.

[0029] Step A2: Add 6g of the intermediate to 20mL of N,N-dimethylformamide and stir to dissolve. Then add 30mL of isopropanol and 0.1mL of acetic acid and mix well. Finally, expose the mixture to ultraviolet light at a wavelength of 350nm at 6mW / cm². 3 The irradiation reaction was carried out at the specified irradiance for 4 days, followed by precipitation in deionized water. The product was then purified by silica gel column chromatography using petroleum ether and ethyl acetate at a volume ratio of 1:1 to obtain the reversible crosslinking agent.

[0030] Example 2

[0031] This embodiment provides a reversible crosslinking agent, which is prepared through the following steps:

[0032] Step A1: Add 8.6g of 4,4"-dihydroxybenzophenone and 11.5g of anhydrous potassium carbonate to 25mL of N,N-dimethylformamide and stir to mix. Then add 12g of 2-bromoethanol dropwise. Stir and react for 24h under nitrogen protection and at 90℃. After cooling to room temperature, filter. Add deionized water to the filtrate to precipitate. After vacuum filtration, freeze-dry the precipitate to obtain the intermediate.

[0033] Step A2: Add 6g of the intermediate to 20mL of N,N-dimethylformamide and stir to dissolve. Then add 40mL of isopropanol and 0.1mL of acetic acid and mix well. Finally, expose the mixture to ultraviolet light at a wavelength of 380nm at 5mW / cm². 3 The irradiation reaction was carried out at the specified irradiance for 5 days, followed by precipitation in deionized water. The product was then purified by silica gel column chromatography using petroleum ether and ethyl acetate at a volume ratio of 1:1 to obtain a reversible crosslinking agent.

[0034] Example 3

[0035] This embodiment provides a reversible crosslinking agent, which is prepared through the following steps:

[0036] Step A1: Add 8.6g of 4,4"-dihydroxybenzophenone and 12g of anhydrous potassium carbonate to 30mL of N,N-dimethylformamide and stir to mix. Then add 12.5g of 2-bromoethanol dropwise. Stir and react for 24h under nitrogen protection and at 90℃. After cooling to room temperature, filter. Add deionized water to the filtrate to precipitate. After vacuum filtration, freeze-dry the precipitate to obtain the intermediate.

[0037] Step A2: Add 6g of the intermediate to 20mL of N,N-dimethylformamide and stir to dissolve. Then add 50mL of isopropanol and 0.1mL of acetic acid and mix well. Finally, expose the mixture to ultraviolet light at a wavelength of 395nm at 4mW / cm². 3 The irradiation reaction was carried out at the specified irradiance for 6 days, followed by precipitation in deionized water. The product was then purified by silica gel column chromatography eluted with petroleum ether and ethyl acetate at a volume ratio of 1:1 to obtain a reversible crosslinking agent.

[0038] Comparative Example 1

[0039] This comparative example provides a crosslinking agent whose structure does not contain carbon-carbon dynamic covalent bonds, and is prepared by the following steps:

[0040] 15.4 g of tetrakis(4-hydroxyphenyl)methane and 12 g of anhydrous potassium carbonate were added to 30 mL of N,N-dimethylformamide and stirred. Then, 22.5 g of 2-bromoethanol was added dropwise. The mixture was stirred and reacted at 90 °C under nitrogen protection for 24 h. After cooling to room temperature, the mixture was filtered. The filtrate was added to deionized water for precipitation. After vacuum filtration, the precipitate was freeze-dried to obtain the crosslinking agent.

[0041] Comparative Example 2

[0042] Compared with Example 3, this comparative example omits step A1 and directly uses 4,4"-dihydroxybenzophenone as an intermediate for subsequent irradiation reactions, while the other raw materials and steps remain the same.

[0043] Example 4

[0044] This embodiment provides a reversible crosslinking polyurethane modifier, which is prepared through the following steps:

[0045] 10g of polytetrahydrofuran with a molecular weight of 1800g / mol was heated and melted at 100℃ and evacuated for 2h. After cooling to 60℃, 0.05g of dibutyltin dilaurate and 100mL of N,N-dimethylformamide mixed solution were added dropwise, followed by the slow addition of 1.8g of hexamethylene diisocyanate. After the addition was completed, the mixture was stirred at 60℃ for 4h under nitrogen protection to obtain a prepolymer solution. 0.5g of 4-(4'-hydroxyphenyl)-2,3-diazanaphth-1-one and 1.82g of the reversible crosslinking agent prepared in Example 1 were added to the prepolymer solution, and the mixture was reacted at 45℃ for 18h. After vacuum drying, a reversible crosslinking polyurethane modifier was obtained.

[0046] Example 5

[0047] This embodiment provides a reversible crosslinking polyurethane modifier, which is prepared through the following steps:

[0048] 10g of polytetrahydrofuran with a molecular weight of 2000g / mol was heated and melted at 100℃ and evacuated for 2h. After cooling to 60℃, 0.05g of dibutyltin dilaurate and 100mL of N,N-dimethylformamide mixed solution were added dropwise, followed by the slow addition of 1.9g of hexamethylene diisocyanate. After the addition was completed, the mixture was stirred at 60℃ for 5h under nitrogen protection to obtain a prepolymer solution. 0.8g of 4-(4'-hydroxyphenyl)-2,3-diazanaphth-1-one and 2.6g of the reversible crosslinking agent prepared in Example 2 were added to the prepolymer solution, and the mixture was reacted at 45℃ for 20h. After vacuum drying, a reversible crosslinking polyurethane modifier was obtained.

[0049] Example 6

[0050] This embodiment provides a reversible crosslinking polyurethane modifier, which is prepared through the following steps:

[0051] 10g of polytetrahydrofuran with a molecular weight of 2000g / mol was heated and melted at 100℃ and evacuated for 2h. After cooling to 60℃, 0.05g of dibutyltin dilaurate and 100mL of a mixed solution of N,N-dimethylformamide were added dropwise, followed by the slow addition of 2g of hexamethylene diisocyanate. After the addition was completed, the mixture was stirred at 60℃ under nitrogen protection for 6h to obtain a prepolymer solution. 1g of 4-(4'-hydroxyphenyl)-2,3-diazanaphth-1-one and 3.03g of the reversible crosslinking agent prepared in Example 3 were added to the prepolymer solution, and the mixture was reacted at 45℃ for 24h. After vacuum drying, a reversible crosslinking polyurethane modifier was obtained.

[0052] Comparative Example 3

[0053] The difference between this comparative example and Example 6 is that hydroquinone dihydroxyethyl ether was used as a chain extender to replace 4-(4'-hydroxyphenyl)-2,3-diazanaphth-1-one in an equal amount, while the other raw materials and steps were the same to obtain a polyurethane modifier.

[0054] Comparative Example 4

[0055] The difference between this comparative example and Example 6 is that the crosslinking agent prepared in Comparative Example 1 is used to replace the reversible crosslinking agent prepared in Example 3, while the other raw materials and steps are the same, to obtain a polyurethane modifier.

[0056] Comparative Example 5

[0057] The difference between this comparative example and Example 6 is that the crosslinking agent prepared in Comparative Example 2 is used to replace the reversible crosslinking agent prepared in Example 3, while the other raw materials and steps are the same, to obtain a polyurethane modifier.

[0058] Example 7

[0059] This embodiment provides a fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds, comprising the following raw materials in parts by weight: 100 parts of 70# base asphalt, 2 parts of the reversible crosslinking polyurethane modifier prepared in Example 4, and 1 part of compatibilizer.

[0060] This type of fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds is prepared by the following steps:

[0061] The base asphalt was heated to 130℃ and stirred until melted. Then, the compatibilizer and reversible crosslinking polyurethane modifier were added to the melted base asphalt. The temperature was maintained and sheared at a shear rate of 1500 rpm for 30 minutes. The mixture was then placed in an oven at 50℃ for 6 hours and cooled to room temperature to obtain fast-dissolving high-viscosity modified asphalt.

[0062] Example 8

[0063] This embodiment provides a fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds, comprising the following raw materials in parts by weight: 100 parts of 70# base asphalt, 5 parts of the reversible crosslinking polyurethane modifier prepared in Example 5, and 1.5 parts of compatibilizer.

[0064] This type of fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds is prepared by the following steps:

[0065] The base asphalt was heated to 135℃ and stirred until melted. Then, the compatibilizer and reversible crosslinking polyurethane modifier were added to the melted base asphalt. The temperature was maintained and sheared at a shear rate of 1500 rpm for 30 minutes. The mixture was then placed in an oven at 55℃ for 5 hours and cooled to room temperature to obtain fast-dissolving high-viscosity modified asphalt.

[0066] Example 9

[0067] This embodiment provides a fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds, comprising the following raw materials in parts by weight: 100 parts of 70# base asphalt, 8 parts of the reversible crosslinking polyurethane modifier prepared in Example 6, and 2 parts of compatibilizer.

[0068] This type of fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds is prepared by the following steps:

[0069] The base asphalt was heated to 140℃ and stirred until melted. Then, the compatibilizer and reversible crosslinking polyurethane modifier were added to the melted base asphalt. The temperature was maintained and sheared at a shear rate of 1500 rpm for 30 minutes. The mixture was then placed in an oven at 60℃ for 4 hours and cooled to room temperature to obtain fast-dissolving high-viscosity modified asphalt.

[0070] Comparative Example 6

[0071] The difference between this comparative example and Example 9 is that the polyurethane modifier prepared in Comparative Example 3 is used to replace the reversible crosslinking polyurethane modifier prepared in Example 6 in an equal amount, while the other raw materials and steps are the same.

[0072] Comparative Example 7

[0073] The difference between this comparative example and Example 9 is that the polyurethane modifier prepared in Comparative Example 4 is used to replace the reversible crosslinking polyurethane modifier prepared in Example 6 in an equal amount, while the other raw materials and steps are the same.

[0074] Comparative Example 8

[0075] The difference between this comparative example and Example 9 is that the polyurethane modifier prepared in Comparative Example 5 is used to replace the reversible crosslinking polyurethane modifier prepared in Example 6 in an equal amount, while the other raw materials and steps are the same.

[0076] The modified asphalts prepared in Examples 7-9 and Comparative Examples 6-8 were tested according to the JTG E20-2011 test procedure. The results are shown in Table 1.

[0077] Table 1

[0078] Test Project Example 7 Example 8 Example 9 Comparative Example 6 Comparative Example 7 Comparative Example 8 Needle penetration (25℃, 0.1mm) 46.1 45.7 44.3 56.2 45.5 44.1 Softening point (°C) 80.8 81.3 82.5 61.5 84.6 67.4 Ductility at 5℃ (cm) 31.5 33.4 34.6 37.3 32.2 26.7 Viscosity and toughness at 25℃ (N·m) 27.7 28.2 29.8 22.4 25.5 21.9 Dynamic viscosity at 60℃ (Pa·s) 163000 171000 178000 135000 146000 224000

[0079] As can be seen from the data in Table 1, the modified asphalt prepared in Examples 7-9 has a smaller penetration, indicating that it has high strength and superior resistance to deformation, and is less prone to rutting under heavy loads; the modified asphalt prepared in Examples 7-9 has a higher softening point, indicating excellent heat resistance, and is less prone to deformation in high-temperature environments during service; the modified asphalt prepared in Examples 7-9 has higher ductility and viscosity-toughness, indicating superior strength and toughness; the modified asphalt prepared in Examples 7-9 has an appropriate dynamic viscosity, which maintains excellent resistance to rutting without affecting the fluidity and processability of the modified asphalt.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0081] Although embodiments of the invention have been shown and described, those skilled in the art will recognize that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds, characterized in that, The raw materials include the following parts by weight: 100 parts of base bitumen, 2-8 parts of reversible crosslinking polyurethane modifier, and 1-2 parts of compatibilizer; The reversible crosslinking polyurethane modifier is prepared by the following steps: Polytetrahydrofuran was heated to 100°C and melted under vacuum for 2 hours to remove moisture. After cooling to 60°C, a mixed solution of dibutyltin dilaurate and N,N-dimethylformamide was added dropwise, followed by the slow addition of hexamethylene diisocyanate. After the addition was complete, the mixture was stirred at 60°C under nitrogen protection for 4-6 hours to obtain a prepolymer solution. A chain extender and a reversible crosslinking agent, 4-(4'-hydroxyphenyl)-2,3-diazanaphth-1-one, were added to the prepolymer solution. The mixture was reacted at 45°C for 18-24 hours and then dried under vacuum to obtain a reversible crosslinking polyurethane modifier. The reversible crosslinking agent is prepared by the following steps: Step A1: Add 4,4"-dihydroxybenzophenone and anhydrous potassium carbonate to N,N-dimethylformamide and stir to mix. Then add 2-bromoethanol dropwise. Under nitrogen protection and at 90°C, stir and react for 24 hours. After cooling to room temperature, filter. Add deionized water to the filtrate to precipitate. After vacuum filtration, dry the precipitate to obtain the intermediate. Step A2: Add the intermediate to N,N-dimethylformamide and stir to dissolve. Then add isopropanol and acetic acid and mix well. Expose to ultraviolet light for 4-6 days for irradiation. Then pour into deionized water for precipitation. After purification, the reversible crosslinking agent is obtained.

2. The fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds according to claim 1, characterized in that, The ratio of polytetrahydrofuran, dibutyltin dilaurate, N,N-dimethylformamide and hexamethylene diisocyanate, chain extender and reversible crosslinking agent is 10g:0.05g:100mL:1.8-2g:0.5-1g:1.82-3.03g.

3. The fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds according to claim 1, characterized in that, The molecular weight of the polytetrahydrofuran is 1800-2000 g / mol.

4. The fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds according to claim 1, characterized in that, The ratio of 4,4"-dihydroxybenzophenone, anhydrous potassium carbonate, N,N-dimethylformamide and 2-bromoethanol is 8.5-8.6g: 11-12g: 20-30mL: 11.3-12.5g.

5. The fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds according to claim 1, characterized in that, The ratio of the intermediate, N,N-dimethylformamide, isopropanol and acetic acid is 6g:20mL:30-50mL:0.1mL.

6. The fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds according to claim 1, characterized in that, The ultraviolet light has a wavelength of 350-395nm and an irradiance of 4-6mW / cm². 3 .

7. The fast-dissolving, high-viscosity modified asphalt based on reversible dynamic bonds according to claim 1, characterized in that, The compatibilizer is octylphenol polyoxyethylene ether.

8. The method for preparing rapidly soluble high-viscosity modified asphalt based on reversible dynamic bonds according to claim 1, characterized in that, Includes the following steps: The base asphalt is heated to 130-140℃ and stirred until melted. Then, the compatibilizer and reversible crosslinking polyurethane modifier are added to the melted base asphalt. The temperature is maintained and shearing is performed. The asphalt is then cured at 50-60℃ for 4-6 hours and cooled to room temperature to obtain fast-dissolving high-viscosity modified asphalt.