An ultraviolet aging resistant asphalt and a preparation method thereof

Abstract

The application relates to the technical field of asphalt materials, and particularly discloses an ultraviolet aging-resistant asphalt and a preparation method thereof. The ultraviolet aging-resistant asphalt is prepared from the following raw materials in parts by weight: 100-150 parts of base asphalt, 1-5 parts of a rare earth organic complex, 2-8 parts of light-responsive polymer microspheres, 3-5 parts of petroleum resin, 2-4 parts of liquid butadiene-styrene rubber, 0.6-1.2 parts of an organic boron crosslinking agent, 1-3 parts of an interface compatibilizer and 0.1-0.5 parts of an antioxidant. The rare earth organic complex is a ternary organic complex of europium. The light-responsive polymer microspheres are core-shell structure polymer microspheres with a styrene-butyl acrylate copolymer as the core and a polyacrylate containing cinnamyl methacrylate as the shell. The product can be applied to highway pavement and building waterproof engineering in high-altitude and strong-sunlight areas, has excellent ultraviolet aging resistance, can effectively solve the problems of hardening and brittle cracking and performance attenuation of asphalt during long-term service, and has stable road performance and long service life.

Description

Technical Field

[0001] This application relates to the field of asphalt technology, and more specifically, to an anti-UV aging asphalt and its preparation method. Background Technology

[0002] Asphalt is an indispensable cementitious material for road paving and building waterproofing projects. It consists of four components: saturated components, aromatic components, resins, and asphaltenes. Due to its excellent bonding properties, plasticity, and waterproofing performance, it is widely used in high-grade highways, municipal roads, and roof waterproofing projects. However, asphalt is a heat- and photosensitive material. When exposed to the open environment for extended periods, the medium- and short-wave ultraviolet rays in sunlight continuously bombard the organic macromolecules inside the asphalt, inducing photooxidative degradation reactions. This causes the lightweight components of the asphalt to volatilize and the resins to transform into asphaltenes, resulting in asphalt hardening, decreased ductility, low-temperature brittleness, and debonding at the aggregate interface. This significantly shortens the actual service life of asphalt pavements and waterproofing structures, especially in high-altitude and high-sunlight areas where the road damage caused by ultraviolet aging is more pronounced.

[0003] In related technologies, such as the patent document with publication number CN106046811B, a modified asphalt with high resistance to ultraviolet aging is disclosed. By weight fraction, it is composed of the following raw materials: 74.8%-76.9% matrix asphalt, 9.8%-13.6% obsidian, 5.2%-7.6% bauxite, 3.0%-4.0% hydrogenated castor oil, and 2.0%-3.2% aluminum-zirconium coupling agent, with the sum of the weight percentages of the raw materials being 100%. The modified asphalt produced by the above technical solution is applied to asphalt pavement. It achieves partial ultraviolet blocking through the physical shielding effect of natural mineral powders, and optimizes the interfacial bonding force between the mineral filler and the asphalt matrix with the help of coupling agents. This improves, to a certain extent, the conventional mechanical properties and initial anti-aging ability of asphalt, which are affected by cracking due to brittleness and hardening, effectively extending the maintenance cycle and service life of the pavement.

[0004] However, the modified asphalt described above still suffers from insufficient resistance to ultraviolet aging in practical engineering applications. Specifically, this solution relies solely on obsidian and bauxite inorganic mineral powders to achieve a single physical ultraviolet shielding effect, which can only block some ultraviolet rays on the surface of the asphalt and cannot eliminate ultraviolet light that penetrates into the interior of the asphalt. This makes it difficult to inhibit the photo-oxidative degradation reaction of organic macromolecules within the asphalt. Furthermore, the inorganic mineral powders have limited compatibility with the asphalt organic matrix, and uneven dispersion and interfacial peeling are likely to occur during long-term service, resulting in a lack of localized ultraviolet protection barriers and poor uniformity of protection. Under long-term strong ultraviolet radiation, asphalt will still experience problems such as loss of lightweight components, structural deterioration, and degradation of mechanical properties. Its long-term resistance to ultraviolet aging is weak, making it difficult to meet the long-term stable service requirements of asphalt pavements in high-altitude, high-sunlight areas. Therefore, the overall ultraviolet aging resistance of asphalt in related technologies still needs further optimization and improvement. Summary of the Invention

[0005] To further optimize and improve the UV aging resistance of asphalt, this application provides UV-resistant asphalt and its preparation method.

[0006] The UV-resistant asphalt provided in this application adopts the following technical solution: An anti-UV aging asphalt comprises the following raw materials in parts by weight: 100-150 parts of base bitumen; 1-5 parts of rare earth organic complex; 2-8 parts of photoresponsive polymer microspheres; 3-5 parts petroleum resin; 2-4 parts of liquid styrene-butadiene rubber; 0.6-1.2 parts of organoboron crosslinking agent; 1-3 parts of interface compatibilizer; Antioxidant 0.1-0.5 parts; The rare earth organic complex is a europium ternary organic complex; The photoresponsive polymer microspheres are core-shell polymer microspheres with a styrene-butyl acrylate copolymer as the core and a polyacrylate containing cinnamic acid ester as the shell.

[0007] By adopting the above technical solution, firstly, the introduced europium ternary organic complex, as a photoinduced downconversion luminescent material, can absorb high-energy ultraviolet photons at the molecular level and then convert them into visible-red photons through the energy transfer pathway of ligand sensitization-central ion luminescence. This process achieves a harmless conversion of ultraviolet light energy, completely eliminating the bombardment and damage capability of ultraviolet photons on the chemical bonds of organic macromolecules inside asphalt. Furthermore, red light has no significant degradation effect on the asphalt matrix, inhibiting the initiation of photooxidative degradation reactions from the photophysical source. Compared to the mechanism of conventional organic ultraviolet absorbers converting light energy into heat energy, the rare-earth downconversion pathway of this solution avoids the local thermal aging problem that may be caused by heat accumulation, resulting in a more thorough protective effect.

[0008] Secondly, core-shell structured photoresponsive polymer microspheres, with a styrene-butyl acrylate copolymer as the core and a polyacrylate containing cinnamic acid ester as the shell, undergo an addition reaction of the cinnamic acid ester groups in the shell under ultraviolet light irradiation. This directly consumes ultraviolet photons and stores their energy in the form of cyclobutane four-membered ring chemical bond energy. This photochemical reaction makes the microspheres into countless microscopic "ultraviolet photochemical circuit breakers" uniformly dispersed inside the asphalt, capturing and consuming ultraviolet photons before they reach the asphalt macromolecules, forming an active sacrificial protection. At the same time, this cycloaddition reaction can undergo a reverse reaction dissociation under the high temperature conditions of summer road surfaces, endowing the microspheres with dynamic and reversible crosslinking-decrosslinking characteristics. This allows the asphalt network to be moderately strengthened under strong ultraviolet light and to regain flexibility when the temperature rises, avoiding the long-term hardening and cracking problem caused by the irreversible crosslinking accumulation of traditional crosslinked modified asphalt, and achieving a dynamic balance of mechanical properties during long-term service.

[0009] The combination of petroleum resin and liquid styrene-butadiene rubber with an organoboron crosslinking agent can construct a micro-region crosslinking toughening network in the asphalt matrix, improving the asphalt's high-temperature deformation resistance and low-temperature crack resistance. The interfacial compatibilizer effectively enhances the dispersion uniformity and interfacial bonding strength of rare earth organic complexes and polymer microspheres in the asphalt organic matrix, preventing the exudation or aggregation of functional components and ensuring the integrity and durability of the UV protection network. The addition of antioxidants synergistically inhibits thermo-oxidative degradation during thermal processing, ensuring performance stability during the material preparation stage.

[0010] In summary, the above technical solution achieves substantial optimization and improvement of the UV aging resistance of asphalt through the synergistic effect of the raw materials.

[0011] Optionally, the rare earth organic complex is formed by coordination of a trivalent europium ion with a β-diketone first ligand and a nitrogen-containing heterocyclic second ligand; the β-diketone first ligand is one of 2-thiophenecarboxyltrifluoroacetone, acetylacetone, or dibenzoylmethane; the nitrogen-containing heterocyclic second ligand is one of 1,10-phenanthroline or 2,2'-bipyridine.

[0012] By employing the above technical solution, β-diketone ligands exhibit a broad-band absorption capability with a high molar absorptivity in the ultraviolet region, enabling efficient capture of ultraviolet photons and transfer of energy to the central europium ion via intersystem crossing. The nitrogen-containing heterocyclic second ligand (such as 1,10-phenanthroline or 2,2'-bipyridine) acts as a cooperating ligand, occupying the remaining coordination sites of the europium ion. This not only eliminates the fluorescence quenching effect caused by solvent molecule coordination, significantly improving downconversion luminescence efficiency, but also enhances the thermodynamic stability and chemical inertness of the complex, allowing it to withstand the high-temperature processing conditions of asphalt without decomposition or failure. This ligand combination ensures the long-term stable ultraviolet downconversion function of the rare-earth organic complex in the asphalt matrix.

[0013] Optionally, the rare earth organic complex is prepared by the following method: The β-diketone first ligand and the nitrogen-containing heterocyclic second ligand were dissolved in anhydrous ethanol to obtain a ligand solution. The ligand solution was added dropwise to europium nitrate solution under stirring at 200-400 r / min and 40-50℃. After the addition was complete, the pH of the system was adjusted to 6.5-7.5 with 5%-10% ammonia solution. The temperature was raised to 50-60℃ and the reaction was maintained at a constant temperature for 3-5 hours. Then the stirring was stopped and the mixture was allowed to stand at room temperature for 12-24 hours. The precipitate was then collected by filtration, washed, and vacuum dried at 60-80℃ for 20-24 hours to obtain the rare earth organic complex.

[0014] By adopting the above technical solution and using a feeding method of adding the ligand solution dropwise into the europium nitrate solution, it is ensured that europium ions are always in a reaction environment with excess ligands, which is conducive to the full formation of ternary complexes. Controlling the pH of the reaction system to a weakly acidic to neutral range of 6.5-7.5 can avoid the formation of hydroxide precipitates of europium ions under alkaline conditions, ensuring the purity and yield of the complexes. The room temperature static aging step is conducive to the perfect growth of complex crystals and the stabilization of the product. The subsequent washing and vacuum drying processes remove unreacted raw materials and by-products, resulting in rare earth organic complexes with high purity and good crystallinity, which is beneficial for uniform dispersion and stable function in asphalt.

[0015] Optionally, the mass ratio of the β-diketone first ligand, the nitrogen-containing heterocyclic second ligand, and anhydrous ethanol is (2.5-3.2):(1-1.5):(30-50).

[0016] Optionally, the mass concentration of the europium nitrate solution is 5%-15%, and the mass ratio of the ligand solution to the europium nitrate solution is 1:(0.8-1.2).

[0017] Optionally, the photoresponsive polymer microspheres are prepared using the following method: (1) Styrene, butyl acrylate and divinylbenzene are mixed to obtain the core monomer. The core monomer is mixed with sodium dodecyl sulfate aqueous solution and pre-emulsified by stirring at 300-400 r / min for 30-45 min. Nitrogen gas is introduced, the temperature is raised to 75-80℃, potassium persulfate is added, and the reaction is carried out at a constant temperature and stirred for 5-6 h to obtain styrene-butyl acrylate copolymer emulsion. (2) Cinnamyl methacrylate, butyl acrylate and ethylene glycol dimethacrylate are mixed to obtain shell monomer. At 75-80℃, shell monomer and potassium persulfate are added dropwise to styrene-butyl acrylate copolymer emulsion. After the addition is completed, the reaction is kept at a constant temperature for 2-3 hours. After cooling, calcium chloride aqueous solution is added to break the emulsion. After filtration, the mixture is washed with deionized water and dried to obtain photoresponsive polymer microspheres.

[0018] By employing the above technical solution and a two-step seed emulsion polymerization process, a styrene-butyl acrylate copolymer core is first synthesized in the presence of the crosslinking agent divinylbenzene, forming a spherical carrier with moderate rigidity and crosslinking degree, ensuring that the microspheres maintain their morphological integrity during subsequent processing and in high-temperature asphalt media. Subsequently, a shell of cinnamic acid methacrylate, butyl acrylate, and ethylene glycol dimethacrylate is polymerized in situ on the surface of the core latex, forming a chemically bonded, controllable-thickness photoresponsive outer layer. The butyl acrylate segments in the shell effectively improve the interfacial compatibility between the microspheres and the asphalt matrix, preventing microsphere aggregation and phase separation, and providing a uniformly distributed microscopic reaction site for photochemical reactions.

[0019] Optionally, in step (1), the mass ratio of styrene, butyl acrylate and divinylbenzene is (45-55):(35-45):(3-5).

[0020] Optionally, in step (1), the mass concentration of the sodium dodecyl sulfate aqueous solution is 0.5%-1.5%, and the amount of sodium dodecyl sulfate aqueous solution added is 3-5 times the mass of the nuclear monomer; the amount of potassium persulfate added is 0.5%-0.8% of the mass of the nuclear monomer.

[0021] Optionally, in step (2), the mass ratio of cinnamic acid methacrylate, butyl acrylate and ethylene glycol dimethacrylate is (60-75):(25-35):(2-4); the mass ratio of shell monomer and styrene-butyl acrylate copolymer emulsion is (0.8-1.2):1; and the amount of potassium persulfate added is 0.6%-1.0% of the mass of shell monomer.

[0022] By adopting the above technical solution, the monomer ratio of the shell layer, the shell-core mass ratio, and the amount of initiator were limited. Cinnamyl methacrylate, as a photoresponsive monomer, ensures that the shell layer has a sufficient density of cinnamyl ester photosensitive groups, providing ample reaction sites for ultraviolet photochemical capture. The appropriate introduction of butyl acrylate adjusts the flexibility of the shell layer and its compatibility with asphalt. Ethylene glycol dimethacrylate constructs a slightly cross-linked network in the shell layer, preventing the shell layer from swelling and detaching during long-term service. The shell-core mass ratio of 0.8-1.2:1 balances photoresponsive function and microsphere structural integrity.

[0023] This application also provides a method for preparing UV-resistant asphalt, using the following technical solution: A method for preparing UV-resistant asphalt includes the following steps: S1. Heat the base asphalt to 150-160℃ to a fluid state, add petroleum resin and interface compatibilizer under stirring conditions of 300-500r / min, stir for 10-20min, cool down to 130-140℃, then add liquid styrene-butadiene rubber and organoboron crosslinking agent, stir at a speed of 400-600r / min for 30-40min to obtain premixed asphalt; S2. Stir the rare earth organic complex, photoresponsive polymer microspheres and antioxidant at 800-1200 r / min for 10-15 min to obtain a composite powder; mix the composite powder with premixed asphalt, heat to 160-170℃, stir at 500-800 r / min for 60-90 min, then cool to 150-160℃ and stir at 200-300 r / min for 2-3 h to obtain UV-resistant asphalt.

[0024] By employing the above technical solution, rare earth organic complexes, photoresponsive polymer microspheres, and antioxidants are premixed into a composite powder. This powder is then thoroughly dispersed with premixed asphalt at 160-170℃ through high-speed shearing, ensuring that each functional component is uniformly distributed within the asphalt matrix. Finally, the temperature is lowered to 150-160℃ and low-speed stirring is used for further development, providing sufficient time for the polymer microspheres to reach swelling equilibrium and for the functional component interfaces to stabilize, ensuring uniform and stable performance of the final product. This preparation method features distinct process steps, a reasonable temperature window setting, and smooth transitions between steps, facilitating engineering production implementation.

[0025] In summary, this application has the following beneficial effects: 1. This application innovatively introduces europium-based ternary rare earth organic complexes, effectively solving the technical defects of traditional modified asphalt that rely solely on physical shielding, resulting in incomplete UV protection and easy thermal accumulation aging. The rare earth organic complexes used in this application possess excellent UV downconversion luminescence properties, efficiently capturing high-energy UV photons at the molecular level. Through the energy transfer mechanism between ligands and central ions, harmful UV light energy is harmlessly converted into visible light energy for release, eliminating the photo-oxidative degradation reaction of asphalt caused by UV light at the source. Simultaneously, this energy conversion method generates no heat accumulation, completely avoiding the risk of photo-thermal coupling aging. Combined with its excellent high-temperature stability, it can continuously provide protection throughout the entire service life of asphalt, significantly improving the problems of hardening and component loss caused by UV aging in asphalt.

[0026] 2. This application employs core-shell structured photoresponsive polymer microspheres as the core component for dynamic protection, addressing the industry pain points of traditional modified asphalt's single protection mode, long-term irreversible hardening and brittleness, and severe mechanical property degradation. The core-shell microspheres designed in this application can act as microscopic ultraviolet circuit breakers, actively consuming ultraviolet photons through the photoaddition reaction of the cinnamic acid ester groups in the shell, intercepting ultraviolet energy in advance, and protecting the asphalt matrix structure. Simultaneously, this photochemical reaction possesses high-temperature reversible characteristics, enabling dynamic switching between crosslinking and decrosslinking based on light and temperature environments. It enhances the structural stability of asphalt under strong ultraviolet conditions and restores the flexibility of asphalt under high-temperature conditions, effectively avoiding the rigid accumulation defects of traditional asphalt after long-term service, achieving a dynamic balance of asphalt mechanical properties, and significantly improving the long-term crack resistance and damage resistance of the pavement.

[0027] 3. This application solves the technical problems of poor compatibility, uneven protection, and unbalanced comprehensive road performance of traditional mineral-modified asphalt components through a multi-adjuvant synergistic compounding system. The technical solution of this application, combined with an interface compatibilizer, can significantly improve the interfacial bonding strength and dispersion uniformity between the two core functional components and the asphalt matrix, constructing a complete UV protection network across the entire surface. The compounding of petroleum resin, liquid styrene-butadiene rubber, and organic boron crosslinking agent constructs a stable micro-region crosslinking toughening structure for asphalt, simultaneously optimizing the high-temperature deformation resistance and low-temperature crack resistance of asphalt. The addition of trace amounts of antioxidants inhibits thermo-oxidative aging damage during processing, maximizing the retention of core UV protection functions while ensuring the excellent adhesion, flexibility, and other basic road performance of asphalt, achieving a synergistic improvement in asphalt's anti-aging performance and practical road performance. Detailed Implementation

[0028] The present application will be further described in detail below with reference to the embodiments.

[0029] Preparation examples of rare earth organic complexes Preparation Example 1 In this preparation example, a β-diketone first ligand, a nitrogen-containing heterocyclic second ligand, and anhydrous ethanol were selected in a mass ratio of 2.5:1:30. The first ligand was dibenzoylmethane, and the second ligand was 2,2'-bipyridine. The dibenzoylmethane and 2,2'-bipyridine were added to anhydrous ethanol in the above ratio and stirred thoroughly to dissolve, obtaining a ligand solution. A 5% europium nitrate solution was prepared, with two reaction solutions prepared at a mass ratio of ligand solution to europium nitrate solution of 1:0.8. The ligand solution was placed in a stirred reactor, and the stirring speed was controlled at 200 r / min. The system temperature was stabilized at 40℃, and europium nitrate solution was added dropwise at a uniform rate. After the addition was complete, the pH of the reaction system was adjusted to 6.5 using 5% ammonia water, and then the temperature was raised to 50℃ and stirred continuously for 3 hours. After the reaction was completed, stirring was stopped, and the mixture was allowed to stand at room temperature for 12 hours. After aging, the bottom precipitate was collected by filtration. The precipitate was washed three times with anhydrous ethanol and deionized water alternately. The washed precipitate was placed in a vacuum drying oven and dried under vacuum at 60°C for 20 hours to obtain rare earth organic complexes.

[0030] Preparation Example 2 In this preparation example, a β-diketone first ligand, a nitrogen-containing heterocyclic second ligand, and anhydrous ethanol were selected in a mass ratio of 2.85:1.25:40. Acetylacetone was chosen as the first ligand, and 1,10-phenanthroline as the second ligand. The acetylacetone and 1,10-phenanthroline were added to anhydrous ethanol and stirred until completely dissolved to obtain a ligand solution. A 10% europium nitrate solution was prepared, with a ligand solution to europium nitrate solution mass ratio of 1:1. The ligand solution was placed in a reaction vessel, and the stirring speed was controlled at 300 r / min. The system temperature was kept constant at 45℃, and europium nitrate solution was slowly added dropwise. After the addition was complete, the pH of the system was adjusted to 7.0 using 8% ammonia solution, and the temperature was raised to 55℃ and the reaction was maintained at this temperature for 4 hours. After the reaction was completed, the mixture was allowed to stand at room temperature for 18 hours. The precipitate was collected by filtration and washed four times with anhydrous ethanol and deionized water alternately. The precipitate was then placed in a vacuum drying oven and dried under vacuum at 70°C for 22 hours to obtain the rare earth organic complex.

[0031] Preparation Example 3 In this preparation example, a β-diketone first ligand, a nitrogen-containing heterocyclic second ligand, and anhydrous ethanol were selected in a mass ratio of 3.2:1.5:50. The first ligand was 2-thiophenecarboxylic acid trifluoroacetone, and the second ligand was 1,10-phenanthroline. The ligand solution was prepared by dissolving the 2-thiophenecarboxylic acid trifluoroacetone and 1,10-phenanthroline in anhydrous ethanol and stirring thoroughly. A 15% europium nitrate solution was prepared at a mass ratio of 1:1.2. The ligand solution was placed in a stirring apparatus, and the stirring speed was controlled at 400 r / min. The system temperature was maintained at 50℃, and the europium nitrate solution was added dropwise at a uniform rate. After the addition was complete, the pH of the system was adjusted to 7.5 using 10% ammonia solution, and the temperature was raised to 60℃ and reacted for 5 hours. After the reaction was completed, the mixture was allowed to stand at room temperature for 24 hours. The solid precipitate was collected by filtration and impurities were removed by washing with anhydrous ethanol and deionized water multiple times. The precipitate was then placed in a vacuum drying oven and dried under vacuum at 80°C for 24 hours to obtain the rare earth organic complex.

[0032] Example of preparation of photoresponsive polymer microspheres Preparation Example 4 Photoresponsive polymer microspheres were prepared using the following method: (1) Styrene, butyl acrylate and divinylbenzene were mixed in a mass ratio of 45:35:3 to obtain the core monomer. The core monomer was mixed with a 0.5% sodium dodecyl sulfate aqueous solution. The amount of sodium dodecyl sulfate added was 3 times the total mass of the core monomer. The mixture was stirred at 300 r / min for 30 min to pre-emulsify. Nitrogen gas was introduced and the temperature was raised to 75°C. Potassium persulfate of 0.5% of the core monomer mass was added and the mixture was stirred at a constant temperature for 5 h to obtain a styrene-butyl acrylate copolymer emulsion. (2) Cinnamyl methacrylate, butyl acrylate and ethylene glycol dimethacrylate were mixed in a mass ratio of 60:25:2 to obtain shell monomer. At 75°C, shell monomer and potassium persulfate were added dropwise to styrene-butyl acrylate copolymer emulsion. The mass ratio of shell monomer to styrene-butyl acrylate copolymer emulsion was 0.8:1. The amount of potassium persulfate added was 0.6% of the mass of shell monomer. After the addition was completed, the reaction was kept at a constant temperature for 2 hours. After cooling, a 5% calcium chloride aqueous solution was added to break the emulsion. The mixture was filtered, washed with deionized water and dried to obtain photoresponsive polymer microspheres.

[0033] Preparation Example 5 Photoresponsive polymer microspheres were prepared using the following method: (1) Styrene, butyl acrylate and divinylbenzene were mixed in a mass ratio of 50:40:4 to obtain the core monomer. The core monomer was mixed with a 1% sodium dodecyl sulfate aqueous solution. The amount of sodium dodecyl sulfate added was 4 times the total mass of the core monomer. The mixture was stirred at 350 r / min for 40 min to pre-emulsify. Nitrogen gas was introduced and the temperature was raised to 77°C. Potassium persulfate of 0.65% of the core monomer mass was added and the mixture was stirred at a constant temperature for 5.5 h to obtain a styrene-butyl acrylate copolymer emulsion. (2) Cinnamyl methacrylate, butyl acrylate and ethylene glycol dimethacrylate were mixed in a mass ratio of 67:30:3 to obtain shell monomer. At 78°C, shell monomer and potassium persulfate were added dropwise to styrene-butyl acrylate copolymer emulsion. The mass ratio of shell monomer to styrene-butyl acrylate copolymer emulsion was 1:1. The amount of potassium persulfate added was 0.8% of the mass of shell monomer. After the addition was completed, the reaction was kept at a constant temperature for 2.5 h. After cooling, a 5% calcium chloride aqueous solution was added to break the emulsion. The mixture was filtered, washed with deionized water and dried to obtain photoresponsive polymer microspheres.

[0034] Preparation Example 6 Photoresponsive polymer microspheres were prepared using the following method: (1) Styrene, butyl acrylate and divinylbenzene were mixed in a mass ratio of 55:45:5 to obtain the core monomer. The core monomer was mixed with a 1.5% sodium dodecyl sulfate aqueous solution. The amount of sodium dodecyl sulfate added was 5 times the total mass of the core monomer. The mixture was stirred at 400 r / min for 45 min to pre-emulsify. Nitrogen gas was introduced and the temperature was raised to 80°C. Potassium persulfate of 0.8% of the core monomer mass was added and the mixture was stirred at a constant temperature for 6 h to obtain a styrene-butyl acrylate copolymer emulsion. (2) Cinnamyl methacrylate, butyl acrylate and ethylene glycol dimethacrylate were mixed in a mass ratio of 75:35:4 to obtain shell monomer. At 80°C, shell monomer and potassium persulfate were added dropwise to styrene-butyl acrylate copolymer emulsion. The mass ratio of shell monomer to styrene-butyl acrylate copolymer emulsion was 1.2:1. The amount of potassium persulfate added was 1% of the mass of shell monomer. After the addition was completed, the reaction was kept at a constant temperature for 3 hours. After cooling, a 5% calcium chloride aqueous solution was added to break the emulsion. The mixture was filtered, washed with deionized water and dried to obtain photoresponsive polymer microspheres.

[0035] Example Example 1 A UV-resistant asphalt, the raw material composition and dosage of which are shown in Table 1, wherein the base asphalt is 90# base asphalt, the rare earth organic complex is the rare earth organic complex prepared in Preparation Example 1, the photoresponsive polymer microspheres are the photoresponsive polymer microspheres prepared in Preparation Example 4, the petroleum resin is C5 petroleum resin, the organoboron crosslinking agent is tributyl borate, the interface compatibilizer is aluminum zirconate coupling agent, and the antioxidant is antioxidant 1010.

[0036] A method for preparing UV-resistant asphalt includes the following steps: S1. Heat the base asphalt to 150°C until it is in a fluid state. Add petroleum resin and interface compatibilizer under stirring at 300 r / min. Stir for 10 min, cool down to 130°C, and then add liquid styrene-butadiene rubber and organoboron crosslinking agent. Stir at 400 r / min for 30 min to obtain premixed asphalt. S2. The rare earth organic complex, photoresponsive polymer microspheres and antioxidant are stirred at 800 r / min for 10 min to obtain a composite powder. The composite powder is mixed with premixed asphalt, heated to 160℃, stirred at 500 r / min for 60 min, then cooled to 150℃ and stirred at 200 r / min for 2 h to obtain UV-resistant asphalt.

[0037] Example 2 An anti-UV aging asphalt, the raw material composition and dosage of which are shown in Table 1, wherein the base asphalt is 90# base asphalt, the rare earth organic complex is the rare earth organic complex prepared in Preparation Example 2, the photoresponsive polymer microspheres are the photoresponsive polymer microspheres prepared in Preparation Example 5, the petroleum resin is C5 petroleum resin, the organoboron crosslinking agent is tributyl borate, the interface compatibilizer is aluminum zirconate coupling agent, and the antioxidant is antioxidant 1010.

[0038] A method for preparing UV-resistant asphalt includes the following steps: S1. Heat the base asphalt to 155°C until it is in a fluid state. Add petroleum resin and interface compatibilizer under stirring at 400 r / min and stir for 15 min. Cool down to 135°C and then add liquid styrene-butadiene rubber and organoboron crosslinking agent. Stir at 500 r / min for 35 min to obtain premixed asphalt. S2. The rare earth organic complex, photoresponsive polymer microspheres and antioxidant are stirred at 1000 r / min for 12 min to obtain a composite powder; the composite powder is mixed with premixed asphalt, heated to 165℃, stirred at 650 r / min for 75 min, then cooled to 155℃ and stirred at 250 r / min for 2.5 h to obtain UV-resistant asphalt.

[0039] Example 3 An anti-UV aging asphalt, the raw material composition and dosage of which are shown in Table 1, wherein the base asphalt is 90# base asphalt, the rare earth organic complex is the rare earth organic complex prepared in Preparation Example 3, the photoresponsive polymer microspheres are the photoresponsive polymer microspheres prepared in Preparation Example 6, the petroleum resin is C5 petroleum resin, the organoboron crosslinking agent is tributyl borate, the interface compatibilizer is aluminum zirconate coupling agent, and the antioxidant is antioxidant 1010.

[0040] A method for preparing UV-resistant asphalt includes the following steps: S1. Heat the base asphalt to 160℃ to a fluid state, add petroleum resin and interface compatibilizer under stirring at 500r / min, stir for 20min, cool down to 140℃, then add liquid styrene-butadiene rubber and organoboron crosslinking agent, stir at 600r / min for 40min to obtain premixed asphalt. S2. The rare earth organic complex, photoresponsive polymer microspheres and antioxidant are stirred at 1200 r / min for 15 min to obtain a composite powder. The composite powder is mixed with premixed asphalt, heated to 170℃, stirred at 800 r / min for 90 min, then cooled to 160℃ and stirred at 300 r / min for 3 h to obtain UV-resistant asphalt.

[0041] Table 1. Raw material composition and proportions (kg) of asphalt in Examples 1-3

[0042] Example 4 An anti-UV aging asphalt, which differs from Example 3 in that: in this example, the rare earth organic complex is selected from the rare earth organic complex prepared in Preparation Example 2.

[0043] Example 5 An anti-UV aging asphalt differs from Example 3 in that the photoresponsive polymer microspheres in this example are the photoresponsive polymer microspheres prepared in Preparation Example 5.

[0044] Example 6 An anti-UV aging asphalt, which differs from Example 3 in that the petroleum resin in this example is C9 petroleum resin.

[0045] Example 7 An anti-UV aging asphalt differs from Example 3 in that the interface compatibilizer used in this example is a titanate coupling agent.

[0046] Comparative Example Comparative Example 1 An asphalt was prepared according to Example 1 in the patent document with announcement number CN106046811B, entitled "A Modified Asphalt with High Resistance to Ultraviolet Aging".

[0047] Comparative Example 2 An anti-UV aging asphalt, which differs from Example 3 in that: no rare earth organic complexes were added in this comparative example.

[0048] Comparative Example 3 An anti-UV aging asphalt, which differs from Example 3 in that: no photoresponsive polymer microspheres were added in this comparative example.

[0049] Comparative Example 4 An anti-UV aging asphalt, which differs from Example 3 in that liquid styrene-butadiene rubber was not added in this comparative example.

[0050] Performance testing The performance of the asphalt samples prepared in Examples 1-7 and Comparative Examples 1-4, as well as 90# base asphalt (blank group) were tested.

[0051] The tests include thin-film oven aging tests, ultraviolet aging tests, asphalt penetration before and after aging, softening point, ductility (low-temperature ductility, taken at 5℃), and kinematic viscosity at 135℃, etc., specifically referring to JTGE20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering". During aging, the asphalt samples are first subjected to a thin-film oven aging test, and then placed in an artificial high-intensity ultraviolet light source environment chamber, with the temperature inside the chamber controlled (ultraviolet intensity 1200 μW / cm²). 2 The temperature was 60℃±2℃). The total daily ultraviolet radiation time in the artificial strong ultraviolet light source environment chamber was 16 hours (5:00-21:00), with an interval of 8 hours, for 10 consecutive days. The test results are shown in Table 2.

[0052] Table 2 Test Results

[0053] Analysis of the test results in Table 2, combined with the performance data before and after aging, shows that the UV-resistant asphalt prepared in this application has extremely superior long-term UV-resistant performance compared to traditional modified asphalt and ordinary base asphalt. The blank group (90# base asphalt) showed extremely significant performance degradation after UV aging. After aging, the penetration dropped sharply from 8.84 mm to 4.26 mm, the ductility at 5℃ was only 0.6 cm, the softening point increased significantly, and the kinematic viscosity increased significantly. This indicates that pure asphalt undergoes severe photo-oxidative degradation under strong UV irradiation, resulting in a large loss of lightweight components and rapid hardening and embrittlement of the matrix. This is the core reason why open-air asphalt pavements are prone to cracking and damage. In contrast, the modified asphalt in Examples 1-7 of this application showed very little change in various indicators before and after aging. Especially in Example 3 with the optimal mix ratio, the penetration, ductility, and viscosity remained basically stable after aging, with no obvious hardening or embrittlement. This fully verifies the highly efficient UV protection capability of the composite modification system in this application.

[0054] Compared with the mineral-modified asphalt in Comparative Example 1, the technical solution of this application exhibits a significantly superior advantage in resisting ultraviolet aging. Comparative Example 1 employs a traditional physical shielding protection mode using inorganic mineral powders, which can only block surface ultraviolet rays and cannot inhibit the photo-oxidation reaction inside the asphalt. After ultraviolet aging, the penetration decreases drastically, the ductility drops sharply, the softening point increases dramatically, the rigidity of the asphalt increases significantly, and the toughness is essentially lost, resulting in extremely poor long-term service performance. In contrast, this application relies on the ultraviolet downconversion mechanism of europium-based ternary rare earth organic complexes to convert harmful ultraviolet light energy into harmless visible light at the molecular level, while eliminating the risk of heat accumulation aging and completely overcoming the limitations of physical shielding protection. Data shows that the ductility retention rate after aging in each embodiment is much higher than that in Comparative Example 1, and the low-temperature crack resistance of the asphalt remains stable after ultraviolet aging, effectively solving the technical pain points of incomplete ultraviolet aging resistance and severe long-term performance degradation of traditional modified asphalt.

[0055] Comparing the data of Example 3 with Comparative Examples 2 and 3, it is evident that the UV resistance of asphalt significantly decreases when either the rare-earth organic complex or the photoresponsive polymer microspheres are absent. Comparative Example 2, without the rare-earth organic complex, exhibits a post-aging ductility of only 4.8 cm and a significantly increased penetration decay, demonstrating that rare-earth downconversion luminescence protection is the core basis for blocking UV photo-oxidation. Comparative Example 3, without the photoresponsive polymer microspheres, shows a post-aging ductility as low as 3.9 cm, highlighting the asphalt's hardening and embrittlement problems, verifying the irreplaceable role of core-shell microspheres in dynamically reversible UV interception and structural regulation. The two core components work together to construct a comprehensive UV protection network from both light energy conversion and photochemical interception dimensions, while dynamically balancing the mechanical properties of asphalt, thus avoiding the irreversible hardening defects of traditional asphalt.

[0056] The stable and excellent performance data of each embodiment proves that the components of this application have strong synergistic compatibility. While significantly improving the UV aging resistance of asphalt, it can perfectly take into account the basic road performance of asphalt in terms of high temperature deformation resistance and low temperature crack resistance, and is suitable for complex service environments such as strong sunlight and high altitude.

[0057] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A UV-resistant asphalt, characterized in that, The raw materials include the following parts by weight: 100-150 parts of base asphalt; 1-5 parts of rare earth organic complex; 2-8 parts of photoresponsive polymer microspheres; 3-5 parts of petroleum resin; 2-4 parts of liquid styrene-butadiene rubber; 0.6-1.2 parts of organoboron crosslinking agent; 1-3 parts of interface compatibilizer; and 0.1-0.5 parts of antioxidant. The rare earth organic complex is a europium ternary organic complex. The photoresponsive polymer microspheres are core-shell polymer microspheres with a styrene-butyl acrylate copolymer as the core and a polyacrylate containing cinnamic acid ester as the shell. The rare earth organic complex is formed by coordination of a trivalent europium ion with a β-diketone first ligand and a nitrogen-containing heterocyclic second ligand; the β-diketone first ligand is one of 2-thiophenecarboxyltrifluoroacetone, acetylacetone, or dibenzoylmethane; the nitrogen-containing heterocyclic second ligand is one of 1,10-phenanthroline or 2,2'-bipyridine. The photoresponsive polymer microspheres were prepared by the following method: (1) Styrene, butyl acrylate and divinylbenzene were mixed to obtain a core monomer, and the core monomer was mixed with an aqueous solution of sodium dodecyl sulfate and pre-emulsified by stirring at 300-400 r / min for 30-45 min. Nitrogen gas was introduced, the temperature was raised to 75-80℃, potassium persulfate was added, and the reaction was stirred at a constant temperature for 5-6 hours to obtain a styrene-butyl acrylate copolymer emulsion; (2) cinnamate methacrylate, butyl acrylate and ethylene glycol dimethacrylate were mixed to obtain a shell monomer. At 75-80℃, the shell monomer and potassium persulfate were added dropwise to the styrene-butyl acrylate copolymer emulsion. After the addition was completed, the reaction was carried out at a constant temperature for 2-3 hours. After cooling, calcium chloride aqueous solution was added to break the emulsion. After filtration, the mixture was washed with deionized water and dried to obtain photoresponsive polymer microspheres.

2. The UV-resistant asphalt according to claim 1, characterized in that, The rare earth organic complex was prepared by the following method: a β-diketone first ligand and a nitrogen-containing heterocyclic second ligand were dissolved in anhydrous ethanol to obtain a ligand solution. Europium nitrate solution was added dropwise to the ligand solution under stirring at 200-400 r / min and at 40-50℃. After the addition was complete, the pH of the system was adjusted to 6.5-7.5 with 5%-10% ammonia solution. The temperature was raised to 50-60℃ and the reaction was maintained at this temperature for 3-5 hours. Then, stirring was stopped, and the mixture was allowed to stand at room temperature for 12-24 hours. The precipitate was then collected by filtration, washed, and vacuum dried at 60-80℃ for 20-24 hours to obtain the rare earth organic complex.

3. The UV-resistant asphalt according to claim 2, characterized in that: The mass ratio of the β-diketone first ligand, the nitrogen-containing heterocyclic second ligand, and anhydrous ethanol is (2.5-3.2):(1-1.5):(30-50).

4. The UV-resistant asphalt according to claim 2, characterized in that: The mass concentration of the europium nitrate solution is 5%-15%, and the mass ratio of the ligand solution to the europium nitrate solution is 1:(0.8-1.2).

5. The UV-resistant asphalt according to claim 1, characterized in that: In step (1), the mass ratio of styrene, butyl acrylate and divinylbenzene is (45-55):(35-45):(3-5).

6. The UV-resistant asphalt according to claim 1, characterized in that: In step (1), the mass concentration of the sodium dodecyl sulfate aqueous solution is 0.5%-1.5%, and the amount of sodium dodecyl sulfate aqueous solution added is 3-5 times the mass of the nuclear monomer; the amount of potassium persulfate added is 0.5%-0.8% of the mass of the nuclear monomer.

7. The UV-resistant asphalt according to claim 1, characterized in that: In step (2), the mass ratio of cinnamic acid methacrylate, butyl acrylate and ethylene glycol dimethacrylate is (60-75):(25-35):(2-4); the mass ratio of shell monomer and styrene-butyl acrylate copolymer emulsion is (0.8-1.2):1; and the amount of potassium persulfate added is 0.6%-1.0% of the mass of shell monomer.

8. A method for preparing UV-resistant asphalt according to any one of claims 1-7, characterized in that, The process includes the following steps: S1. Heat the base asphalt to 150-160℃ to a fluid state, add petroleum resin and interface compatibilizer under stirring at 300-500 r / min, stir for 10-20 min, cool down to 130-140℃, then add liquid styrene-butadiene rubber and organoboron crosslinking agent, stir at 400-600 r / min for 30-40 min to obtain premixed asphalt; S2. Stir rare earth organic complex, photoresponsive polymer microspheres and antioxidant at 800-1200 r / min for 10-15 min to obtain composite powder; mix the composite powder with the premixed asphalt, heat to 160-170℃, stir at 500-800 r / min for 60-90 min, then cool down to 150-160℃, stir at a low speed of 200-300 r / min for 2-3 h to obtain UV-resistant asphalt.

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