Asphalt having a high softening point temperature and a method for producing the same

Abstract

The application provides high softening point temperature asphalt and a preparation method thereof, and belongs to the technical field of asphalt materials. Components of the application include asphalt, star-shaped SBS, LDPE, MAH-g-LDPE, fatty acid-PEG ester / silicon dioxide composite and sulfur stabilizer. The application has the advantages that performance is greatly improved through the synergistic effect of multiple components. Star-shaped SBS and LDPE construct a solid polymer network, MAH-g-LDPE acts as a compatibilizer to ensure system stability, and the innovative fatty acid-PEG / silicon dioxide composite has phase change endothermic and nano-enhancing functions, and intelligently delays temperature rise. The network stability is further enhanced by sulfur crosslinking, and the finally obtained asphalt has extremely high softening point, excellent high-temperature stability, durability and comprehensive road performance, and is suitable for high-end road engineering in harsh environments.

Description

Technical Field

[0001] This invention belongs to the field of asphalt material technology, and particularly relates to a high softening point temperature asphalt and its preparation method. Background Technology

[0002] Asphalt pavement, due to its advantages such as short construction period, good driving comfort, and ease of maintenance, has become the main structural type of high-grade highway pavement in my country, accounting for over 90%. With the intensifying trend of global warming and the frequent occurrence of extreme high temperatures in summer in my country, severe challenges are posed to road infrastructure. As a typical viscoelastic material, asphalt's mechanical and rheological properties are highly sensitive to temperature: at high temperatures, the thermal motion of asphalt molecules intensifies, the material modulus decreases significantly, and it is prone to softening, flowing, and permanent deformation; while at low temperatures, asphalt's increased brittleness leads to a decrease in crack resistance. This temperature sensitivity causes traditional asphalt pavement to suffer frequent damage under extreme climates, mainly manifested as high-temperature damage such as rutting, sulking, and bleeding, and low-temperature damage such as transverse and longitudinal cracks, ultimately resulting in a shortened pavement service life and increased maintenance costs.

[0003] High-temperature resistant asphalt needs to meet a series of stringent performance requirements, which are typically measured using specific evaluation indicators. High-temperature stability is the most fundamental performance requirement for high-temperature resistant asphalt, mainly referring to the asphalt mixture's ability to resist permanent deformation under high-temperature conditions. Commonly used evaluation indicators include rutting factor, softening point, dynamic viscosity at 60℃, and dynamic stability.

[0004] Anti-aging performance is a key indicator for evaluating the long-term durability of asphalt. Asphalt is prone to aging under the influence of ultraviolet radiation, oxygen, and temperature changes, leading to increased viscosity and decreased fluidity. The thin-film oven test (TFOT) is the main method for evaluating the anti-aging performance of asphalt, with the absolute value of mass change (≤0.5%~1.3%) and ductility retention (AH-170 to AH-70 ≥30cm, AH-50 ≥5cm) being important indicators. Fatigue life and environmental performance are also important evaluation indicators for high-temperature resistant asphalt. Fatigue life is evaluated using indicators such as the cumulative energy dissipation ratio; environmental performance focuses on new requirements such as VOCs emission limits.

[0005] Polymer modification is one of the most common methods to improve the high-temperature performance of asphalt. SBS (styrene-butadiene-styrene block copolymer) is the most widely used polymer modifier, which can significantly improve the high-temperature stability and elastic recovery of asphalt. However, SBS-modified asphalt has problems such as high cost (more than 50% higher than the base asphalt), poor storage stability, and a narrow construction temperature window. Epoxy resin modification is another important technology. By forming a three-dimensional interpenetrating network structure with asphalt through epoxy resin, curing agent, and asphalt, the material has better mechanical strength, fatigue resistance, and corrosion resistance. Phenolic resin also has excellent mechanical properties and heat resistance, but its compatibility with asphalt is poor, requiring chemical modification methods such as oleic acid grafting to improve compatibility.

[0006] Nanomaterials offer a new technological approach for asphalt modification. Carbon nanotubes (CNTs) can effectively enhance the high-temperature rutting resistance and fatigue resistance of asphalt, and reduce its sensitivity to aging and water loss. CNTs form a fibrous network structure in asphalt, inhibiting crack propagation through bridging. Rare earth nanomaterials such as nano-cerium oxide and nano-lanthanum oxide possess unique catalytic activity; adding only about 4% by weight of asphalt can inhibit asphalt aging through catalytic oxidation, extending pavement service life by more than 30%. These nanomaterials typically need to be used in conjunction with coupling agents (such as isopropyltris(dioctylpyrophosphate)titanate) to improve their dispersibility and interfacial bonding in asphalt.

[0007] Fiber reinforcement is an effective means to improve the high-temperature stability of asphalt. Glass fiber and pineapple leaf fiber can form a three-dimensional network structure in asphalt through bridging, significantly improving the mixture's resistance to rutting and low-temperature cracking. Pineapple leaf fiber is a model of high-value utilization of agricultural waste. After being treated with pectinase and xylanase and sheared, it can form a uniformly dispersed fiber network in asphalt.

[0008] Despite significant progress in high-temperature resistant asphalt technology, numerous challenges and technical limitations remain. Balancing cost and performance is a major factor restricting the widespread application of high-performance asphalt. While polymer modifiers such as SBS offer excellent performance, their high cost (more than 50% higher than base asphalt) limits their large-scale application. Although nanomaterials offer significant effects with low dosage, their high price and complex dispersion processes make them difficult to meet practical engineering needs.

[0009] Adaptability to construction processes is another prominent issue. The increased viscosity of modified asphalt necessitates strict requirements for mixing and compaction temperatures, shortens the construction window, and easily leads to process defects such as segregation and insufficient compaction. For example, epoxy asphalt requires specific curing conditions and time, posing challenges to on-site construction management.

[0010] Insufficient long-term durability verification is also a shortcoming of existing technologies. Most research on modified asphalt remains at the laboratory stage, lacking long-term performance tracking data in actual engineering. In particular, the environmental impact and potential risks to human health of nanomaterials require further evaluation.

[0011] Environmental protection and resource sustainability face challenges. Although some studies have utilized agricultural waste (such as pineapple leaf fiber) and industrial byproducts (such as diatomaceous earth and rubber powder) as modifiers, large-scale application still requires the establishment of a more robust supply chain and quality control system. Furthermore, energy consumption and emissions during asphalt production also need attention; the new national standard GB / T15180-2025 has begun to focus on environmental indicators such as VOCs emission limits. Summary of the Invention

[0012] The first objective of this invention is to provide an asphalt with a high softening point temperature, comprising the following components by weight:

[0013] Asphalt 100

[0014] Star-shaped SBS 3-4

[0015] LDPE 1-2

[0016] MAH-g-LDPE 0.5-1

[0017] Fatty acid-PEG ester / silica complex 3-5

[0018] Sulfur stabilizer 0.1-0.2;

[0019] The preparation of the fatty acid-PEG ester / silica composite includes the following steps:

[0020] S1: Select fatty acids with a carbon chain length ≥ 22 and PEG with dicarboxyl groups for termination;

[0021] S2: Dissolve fatty acids and dicarboxylated PEG in anhydrous dichloromethane at a molar ratio of 1.05-1.1:1 in a container, and purge with an inert gas; add at least 0.1 mol of 4-dimethylaminopyridine and at least 1.05 mol of N,N'-dicyclohexylcarbodiimide; stir the reaction.

[0022] S3: The reaction is complete when no more white precipitate is produced. Filter the solution and collect the filtrate.

[0023] S4: Concentrate the filtrate and add anhydrous diethyl ether at ≤0℃ dropwise to precipitate the precipitate;

[0024] S5: Collect the diethyl ether and wash it, then vacuum dry it to obtain the fatty acid-PEG complex;

[0025] S6: Amide modification of silica surface using silane coupling agent;

[0026] S7: Encapsulate the fatty acid-PEG complex into aminated silica to obtain a fatty acid-PEG ester / silica complex.

[0027] Preferably, in the preparation of the fatty acid-PEG ester / silica complex, the weight-average molecular weight of the dicarboxylated PEG is ≥4000 and the PDI is ≤1.2.

[0028] Preferably, in the preparation of the fatty acid-PEG ester / silica composite, the silane coupling agent in step S6 is (3-aminopropyl)triethoxysilane, and its addition amount is 1-3% of the volume fraction of silica; the silica is mesoporous silica; and the pore size of the mesoporous silica is ≥30nm.

[0029] Preferably, in the preparation of the fatty acid-PEG ester / silica complex, the mass ratio of the fatty acid-PEG complex to the aminated silica in step S7 is 6-7:3-4.

[0030] Preferably, in the preparation of the fatty acid-PEG ester / silica composite, step S7 involves mixing the fatty acid-PEG composite with aminated silica and placing it in a container, heating it to a temperature higher than the melting point of the fatty acid-PEG composite, and maintaining it in a vacuum for at least 2 hours to allow the fatty acid-PEG composite to melt and impregnate into the pores of the silica; then removing the vacuum and cooling; and then removing the fatty acid-PEG composite from the surface of the aminated silica.

[0031] Preferably, it further includes 0.2-0.5 parts of antioxidants, said antioxidants including hindered phenolic antioxidants and phosphite antioxidants.

[0032] Preferably, it also includes 0.2-0.5 parts of UV protectant.

[0033] Preferably, it also includes 0.2-0.4 parts of an amine anti-stripping agent and 0.2-0.5 parts of a silane coupling agent.

[0034] Preferably, the styrene content in the star-shaped SBS is 30-40%.

[0035] A second objective of this invention is to provide a method for preparing the aforementioned high softening point temperature asphalt, comprising the following steps:

[0036] S1: Heat the asphalt to 160-180℃ under stirring to maintain its fluidity; then, while keeping it at the heat, shear-add star-shaped SBS, LDPE, and MAH-g-LDPE until the polymer is dispersed and dissolved in the asphalt system;

[0037] S2: Reduce the shear rate, add the fatty acid-PEG ester / silica complex and keep stirring for a period of time, then add the remaining components and stir until homogeneous;

[0038] S3: Cool down to 160-170℃ and stop stirring. Seal and let it stand to swell and develop. Once development is complete, it becomes asphalt with a high softening point temperature.

[0039] Selecting appropriate phase change materials (PCMs) to improve the heat resistance of asphalt is of positive significance for alleviating high-temperature pavement distress (such as rutting and shoving) and mitigating the urban heat island effect. Currently, commonly used PCMs in road asphalt include:

[0040] Organic paraffins have the advantages of high latent heat, stable chemical properties, and no supercooling; however, they have the disadvantages of needing to be encapsulated (such as microencapsulation or porous carrier adsorption) to prevent leakage, and needing to pay attention to compatibility with asphalt.

[0041] Organic compounds (polyethylene glycol PEG) have the advantages of good chemical stability and designable phase transition temperature; however, they need to be microencapsulated or combined with porous framework materials for shaping, and the dosage needs to be optimized to prevent a decrease in low-temperature performance.

[0042] Organic fatty acids have better interfacial compatibility with asphalt than inorganic materials; natural fatty acids are non-toxic and biodegradable; however, they may have corrosive or odor issues.

[0043] This invention uses fatty acids and PEG to combine, and encapsulates with silica surface-treated with a coupling agent to prepare a fatty acid-PEG ester / silica composite as a phase change material.

[0044] Compared to single PEG / silica or fatty acid / silica composites, fatty acid-PEG ester / silica composites have the advantage of creating a phase change material through chemical means that synergistically enhances performance and mutually compensates for defects.

[0045] It combines the advantages of PEG and fatty acids, rather than simply mixing them; the phase transition temperature of fatty acids is mainly determined by carbon chain length (e.g., lauric acid C12 approximately 44℃, stearic acid C18 approximately 70℃). The phase transition temperature of PEG is mainly determined by molecular weight (e.g., PEG1000 approximately 37℃, PEG6000 approximately 60℃). The phase transition temperature of fatty acid-PEG esters is not an average of the two components, but a value that can be adjusted through design. By selecting fatty acids with different chain lengths and PEGs with different molecular weights, the phase transition temperature can be precisely set within the desired range, which is not easily achieved through physical mixing.

[0046] An ideal fatty acid-PEG ester molecule can achieve ordered arrangement and energy storage by simultaneously utilizing the van der Waals forces of the fatty acid alkyl chain and the hydrogen bonds and lattice energy of the PEG segments. With proper design, its phase transition enthalpy per unit mass can be slightly higher than that of a single component, achieving an energy storage effect of "1+1≥2".

[0047] It also has advantages in stability and compatibility. Physically mixed PEG / silica or fatty acid / silica: Although silica has strong physical adsorption, there is still a risk of trace PCM molecule migration or leakage under long-term high-temperature cycling or extreme conditions. Fatty acid-PEG ester / silica: Through the bridging effect of silane coupling agents, the terminal functional groups (-COOH) of PCM can form strong chemical bonds such as amide bonds with the functional groups (-NH2) on the silica surface, resulting in unparalleled long-term stability.

[0048] Fatty acid-PEG ester molecules possess both the hydrophobic alkyl chains of fatty acids and the hydrophilic segments of PEG, making them amphiphilic molecules. This structure gives them a natural advantage in complex colloidal systems like asphalt: the hydrophobic end is compatible with the oil components in the asphalt, while the hydrophilic end interacts with mineral aggregates through silica. This significantly reduces the risk of performance inconsistencies or phase separation due to compatibility issues, something that single PCMs cannot achieve.

[0049] In addition, fatty acid-PEG esters provide a chemical platform that is easy to further functionalize; the carboxyl group (-COOH) at the end of its molecule is a highly reactive reaction site. This site can not only be used to anchor to silica, but also to further connect other functional molecules. For example, antioxidant molecules can be directly bonded to PCM to achieve more precise and longer-lasting aging protection.

[0050] The star-shaped core polymer modifier of this invention has multiple arms, which can form a more developed and stable three-dimensional network structure than linear SBS, resulting in a more significant effect on toughening asphalt, improving elastic recovery and high-temperature resistance to permanent deformation (rutting resistance); it greatly enhances the high-temperature performance of asphalt and is a key component of modified asphalt.

[0051] LDPE, or low-density polyethylene, is a crystalline polymer modifier. LDPE melts and disperses at high temperatures, then crystallizes upon cooling, forming physical cross-linking points. This significantly improves the stiffness, strength, and softening point of asphalt; it is also complementary to SBS. SBS provides elasticity, while LDPE provides ductile strength, and the two work synergistically to further enhance high-temperature stability.

[0052] MAH-g-LDPE, or maleic anhydride-grafted low-density polyethylene, is a key reactive compatibilizer. SBS / LDPE and asphalt are physically blended, with generally poor compatibility, and phase separation easily occurs during long-term storage. The maleic anhydride groups in MAH-g-LDPE can react with certain active components in asphalt (such as resins) and the double bonds in SBS, "bridging" at the two-phase interface.

[0053] The two types of LDPE have different functions and cannot be substituted for each other. Ordinary LDPE primarily functions as a main modifier. Its task is to provide rigidity, hardness, and increase the softening point, thereby enhancing the high-temperature performance of asphalt through its own material properties. MAH-g-LDPE primarily functions as a compatibilizer or coupling agent. Its value lies in the maleic anhydride functional groups on its molecular chains, which act as a "bridge" chemically, improving interfacial compatibility; the rigidity and other properties it provides are perhaps secondary. More importantly, MAH-g-LDPE contains strongly polar functional groups; appropriate addition can improve interfacial compatibility. However, excessive introduction of polar components will excessively alter the colloidal structure of asphalt, leading to brittleness at low temperatures, which is detrimental to overall road performance. Simultaneously, the polar MAH-g-LDPE molecules may also attract each other due to polarity. If the concentration is too high, they tend to form aggregates, hindering dispersion.

[0054] Sulfur stabilizers are chemical crosslinking agents. At high temperatures, sulfur can undergo a vulcanization crosslinking reaction with the polybutadiene segments in SBS, transforming the physical polymer network into a partially chemically crosslinked network.

[0055] In addition to the above-mentioned components, the present invention may also incorporate the following types of additives to further improve its performance.

[0056] Antioxidants and UV stabilizers: Asphalt ages and becomes brittle under the influence of heat, oxygen, and ultraviolet radiation; polymers such as SBS are also more prone to aging. Hindered phenolic / phosphite antioxidants work synergistically to resist thermo-oxidative aging; UV stabilizers resist photo-aging. Together, they ensure the long-term durability of modified asphalt and prevent changes in softening point or performance degradation due to aging.

[0057] Amine-based anti-stripping agents and silane coupling agents: These improve the adhesion between asphalt and aggregate (especially acidic aggregate) and prevent water damage. Anti-stripping agents adsorb at the asphalt-aggregate interface; silane coupling agents form chemical bridges at the interface. Together, they ensure the water stability of the asphalt mixture, a key indicator of road performance.

[0058] Although the silica has already undergone silane coupling agent surface treatment in the fatty acid-PEG ester / silica composite, the addition of a small amount of silane coupling agent to the asphalt system is still necessary. Pretreatment of silica aims to alter its surface properties: changing it from hydrophilic to oleophobic, making it substantially compatible with the fatty acid-PEG ester and the oily medium of asphalt. It also prevents the agglomeration of silica nanoparticles: through steric hindrance or electrostatic repulsion, it ensures that the nanoparticles remain dispersed within the composite and during initial addition to asphalt. This solves the fundamental compatibility issues both "within the phase change material composite" and "between the composite and asphalt." Without this step, the composite would immediately agglomerate and fail.

[0059] The added silane coupling agent targets not only the phase change material composite but also the entire asphalt mixture system; it is uniformly dispersed within the asphalt. During subsequent mixing with aggregates, one end (-OR') of these silane molecules hydrolyzes and forms strong covalent bonds (Si-O-Si) with the silanol groups (-SiOH) on the surface of acidic aggregates (such as granite and quartzite). The other end, with its organic functional group (-NH2), tightly binds to the active components in the asphalt (such as asphaltenes and resins) through acid-base interactions or van der Waals forces. This creates a strong, water-resistant chemical bridge between the aggregates and asphalt, significantly improving the asphalt mixture's resistance to water damage. This is a global function that pretreated silica silanes cannot provide.

[0060] Furthermore, during the pretreatment process, the silane coating on the silica surface may not be 100% perfect and may have weak points. During the high-temperature shearing and long-term service of asphalt, the pretreated silane coating may undergo slight degradation or peeling due to thermal, mechanical shearing, or aging. Free silane molecules in the system can migrate to these weak points to "repair" and "replenish," further stabilizing the interface between the phase change material and the asphalt.

[0061] Furthermore, this invention limits the styrene content in the star-shaped SBS to 30-40%. In SBS, the styrene segments provide strength (physical crosslinking points), while the butadiene segments provide elasticity. This content range represents the golden range for balancing high and low temperature performance. Although a higher styrene content can achieve better high-temperature resistance, a higher styrene content is not always better; this is a typical performance balancing issue.

[0062] When the styrene content is too high (e.g., S / B = 50 / 50), the hard segment microdomains of PS become too large and numerous, and may even transform from a dispersed phase to a continuous phase. The material will change from a structure of "mainly elastomer with rigid islands" to a structure of "mainly rigid plastic with elastic islands," posing a risk of phase reversal. SBS itself will change from a rubber to a toughened plastic. The elasticity and toughness of its modified asphalt will decrease sharply, and the material will become hard and brittle.

[0063] Furthermore, the solubility parameters of polystyrene (PS) differ significantly from those of asphalt, while polybutadiene (PB) has much better compatibility with asphalt. Excessive styrene content means that the proportion of the SBS molecule that is poorly compatible with asphalt is too large. This makes it more difficult for SBS to disperse uniformly in asphalt; modified asphalt is more prone to phase separation (segregation), with the polymer phase floating to the surface, leading to inconsistent product performance and failure.

[0064] The advantage of this invention lies in achieving a leap in performance through the synergistic effect of multiple components. Star-shaped SBS and LDPE construct a robust polymer network, while MAH-g-LDPE acts as a compatibilizer to ensure system stability. The innovative fatty acid-PEG / silica composite combines phase change endothermic properties with nano-reinforcement, intelligently delaying temperature rise. Sulfur crosslinking further enhances network stability, resulting in asphalt with an extremely high softening point, excellent high-temperature stability, durability, and comprehensive road performance, making it suitable for high-end pavement engineering in harsh environments. Detailed Implementation

[0065] To better understand the present invention, the present invention will be further described below with reference to specific serial numbers. The terminology used in the serial numbers is for describing specific embodiments and does not constitute a limitation on the scope of protection of the present invention.

[0066] In the specific implementation methods, unless otherwise specified, the experimental methods used are all conventional methods, and the materials and reagents used are all commercially available unless otherwise specified.

[0067] The fatty acids used in this invention are: myristic acid (C14), stearic acid (C18), and behenic acid (C22).

[0068] The silica used in this invention is mesoporous silica; D95 pore size ≥ 30 nm.

[0069] The sulfur stabilizer used in this invention is elemental sulfur (S8).

[0070] The hindered phenolic antioxidant used in this invention is BHT (2,6-di-tert-butyl-p-cresol); the phosphite antioxidant is trinonylphenyl phosphite.

[0071] The hindered amine UV absorber used in this invention is GW-3346; the UV absorber is a benzotriazole UV absorber.

[0072] The amine anti-stripping agent used in this invention is octadecyltrimethylammonium chloride; the silane coupling agent is KH-550 γ-aminopropyltriethoxysilane.

[0073] The SBS used in this invention are Yanshan Petrochemical SBS4303 (S / B ratio of 30:70) and Yanshan Petrochemical SBS4452 (S / B ratio of 40:60).

[0074] The asphalt used in this invention is No. 70 asphalt.

[0075] The LDPE used in this invention is Yanshan Petrochemical 1C7A.

[0076] The average grafting rate of MAH-g-LDPE used in this invention is 1.5%.

[0077] The PEG used in this invention is dicarboxylated capped PEG (polyethylene glycol); its weight-average molecular weight is ≥4000 and PDI ≤1.2.

[0078] Example 1, Preparation of fatty acid-PEG ester / silica composite, includes the following steps;

[0079] S1: Select behenic acid (C22) and dicarboxylated PEG as reaction raw materials; add behenic acid (C22) and dicarboxylated PEG (molar ratio of 1.05:1) to anhydrous dichloromethane in a dry container and purge with nitrogen for protection;

[0080] S2: Add 0.1 mol of 4-dimethylaminopyridine and then slowly add 1.05 mol of N,N'-dicyclohexylcarbodiimide while stirring in an ice-water bath (0-4℃).

[0081] S3: After the addition is complete, move to room temperature and continue stirring for at least 24 hours; then observe for at least 1 hour to see if any new obvious precipitate is formed, indicating that the reaction is complete.

[0082] S4: After the reaction is complete, filter the reaction system to remove the precipitated byproduct N,N'-dicyclohexylurea; collect the filtrate;

[0083] S5: Evaporate the filtrate until it becomes thick, add anhydrous ether at ≤0℃ dropwise, a white precipitate will form and be collected;

[0084] S6: The white precipitate was washed several times with cold ether and dried under vacuum to obtain the fatty acid-PEG-COOH complex;

[0085] S7: Take mesoporous silica, vacuum dry it at 120℃ for 6 hours to remove surface adsorbed water and activate silanol groups;

[0086] Pre-hydrolysis of silane coupling agent: Mix 1% by volume of (3-aminopropyl)triethoxysilane with silicon dioxide and stir magnetically for 0.5 hours at room temperature to allow for complete hydrolysis.

[0087] The pre-hydrolyzed solution is a mixture of deionized water and anhydrous ethanol, wherein the molar amount of deionized water is 1.5 times the total molar amount of ethoxy groups in (3-aminopropyl)triethoxysilane, and the volume of anhydrous ethanol is twice the volume of (3-aminopropyl)triethoxysilane.

[0088] The activated silica was dispersed in anhydrous isopropanol, and then the pre-hydrolyzed silane solution was slowly added dropwise; the mixture was refluxed and stirred at 80°C for 6 hours under nitrogen protection.

[0089] After the reaction was completed, the solid was collected by centrifugation, washed four times with anhydrous ethanol, and then washed once with acetone to completely remove the unreacted silane coupling agent. The obtained aminated silica was then dried in a vacuum oven at 60°C for later use.

[0090] S8: Mix the fatty acid-PEG-COOH complex obtained in S6 and the aminated silica obtained in S7 in a container at a mass ratio of 6:4;

[0091] Place the container in a 90°C oil bath and keep it in a vacuum drying oven or a device connected to a vacuum pump for 2 hours, stirring intermittently to allow the molten fatty acid-PEG-COOH complex to fully penetrate into the pores of silica.

[0092] Remove the vacuum and cool the mixture to room temperature; the PCM will then re-solidify within the pores.

[0093] Slightly heat to a temperature slightly above the melting point of PCM and centrifuge to remove a small amount of excess PCM adhering to the surface of the silica particles, ensuring that all PCM is encapsulated within the pores; thus obtaining a fatty acid-PEG ester / silica composite.

[0094] Example 2, Preparation of fatty acid-PEG ester / silica composite, includes the following steps;

[0095] S1: Select behenic acid (C22) and dicarboxylated PEG as reaction raw materials; add behenic acid (C22) and dicarboxylated PEG (molar ratio of 1.1:1) to anhydrous dichloromethane in a dry container and purge with nitrogen for protection;

[0096] S2: Add 0.1 mol of 4-dimethylaminopyridine and then slowly add 1.05 mol of N,N'-dicyclohexylcarbodiimide while stirring in an ice-water bath (0-4℃).

[0097] S3: After the addition is complete, move to room temperature and continue stirring for at least 24 hours; then observe for at least 1 hour to see if any new obvious precipitate is formed, indicating that the reaction is complete.

[0098] S4: After the reaction is complete, filter the reaction system to remove the precipitated byproduct N,N'-dicyclohexylurea; collect the filtrate;

[0099] S5: Evaporate the filtrate until it becomes thick, add anhydrous ether at ≤0℃ dropwise, a white precipitate will form and be collected;

[0100] S6: The white precipitate was washed several times with cold ether and dried under vacuum to obtain the fatty acid-PEG-COOH complex;

[0101] S7: Take mesoporous silica, vacuum dry it at 120℃ for 6 hours to remove surface adsorbed water and activate silanol groups;

[0102] Pre-hydrolysis of silane coupling agent: Mix 3% by volume of (3-aminopropyl)triethoxysilane with silica and stir magnetically for 0.5 hours at room temperature to allow for complete hydrolysis.

[0103] The pre-hydrolyzed solution is a mixture of deionized water and anhydrous ethanol, wherein the molar amount of deionized water is 1.5 times the total molar amount of ethoxy groups in (3-aminopropyl)triethoxysilane, and the volume of anhydrous ethanol is twice the volume of (3-aminopropyl)triethoxysilane.

[0104] The activated silica was dispersed in anhydrous isopropanol, and then the pre-hydrolyzed silane solution was slowly added dropwise; the mixture was refluxed and stirred at 80°C for 6 hours under nitrogen protection.

[0105] After the reaction was completed, the solid was collected by centrifugation, washed four times with anhydrous ethanol, and then washed once with acetone to completely remove the unreacted silane coupling agent. The obtained aminated silica was then dried in a vacuum oven at 60°C for later use.

[0106] S8: Mix the fatty acid-PEG-COOH complex obtained in S6 and the aminated silica obtained in S7 in a container at a mass ratio of 7:3;

[0107] Place the container in a 90°C oil bath and keep it in a vacuum drying oven or a device connected to a vacuum pump for 2 hours, stirring intermittently to allow the molten fatty acid-PEG-COOH complex to fully penetrate into the pores of silica.

[0108] Remove the vacuum and cool the mixture to room temperature; the PCM will then re-solidify within the pores.

[0109] Slightly heat to a temperature slightly above the melting point of PCM and centrifuge to remove a small amount of excess PCM adhering to the surface of the silica particles, ensuring that all PCM is encapsulated within the pores; thus obtaining a fatty acid-PEG ester / silica composite.

[0110] Example 3, Preparation of fatty acid-PEG ester / silica composite

[0111] The difference from Example 1 is that the fatty acid in step S1 is myristic acid (C14).

[0112] Example 4, Preparation of fatty acid-PEG ester / silica composite

[0113] The difference from Example 1 is that the fatty acid in step S1 is stearic acid (C18).

[0114] Example 5, a method for preparing mixed asphalt, comprising the following steps:

[0115] S1: Weigh the raw materials according to the following mass proportions:

[0116] Asphalt 100

[0117] Yanshan Petrochemical SBS4303 3

[0118] LDPE 1

[0119] MAH-g-LDPE 0.5

[0120] Fatty acid-PEG ester / silica complex (Example 1) 3

[0121] Sulfur stabilizer 0.1;

[0122] S2: Add the weighed asphalt into the reactor, start stirring (300 rpm) and begin heating. Slowly raise the temperature to 175±5℃ to completely melt the asphalt and give it good fluidity;

[0123] Maintain the temperature and add the following in sequence: star-shaped SBS, LDPE, and MAH-g-LDPE;

[0124] During the addition process, the shear rate is gradually increased to a high-speed shear state (4000 rpm). The high shear force is used to quickly break up and homogenize the polymer particles, and to fully disperse and dissolve them in the asphalt matrix.

[0125] Continue high-speed shearing for at least 60 minutes; then, when no undissolved polymer particles are visible to the naked eye and the system becomes uniform, fine, and glossy, it is considered fully dissolved.

[0126] S3: Reduce the shear rate to 800 rpm; slowly add the pre-prepared fatty acid-PEG ester / silica composite, and keep stirring at this moderate stirring rate for 5 minutes to ensure that the composite is evenly distributed in the asphalt;

[0127] Then add the remaining components; continue stirring at medium-low speed for 00 minutes until all components are completely and evenly dispersed.

[0128] S4: Slowly reduce the temperature of the reactor to 170℃; stop stirring and seal the reactor; allow it to stand at this temperature and under sealed conditions for 4 hours to allow it to swell and develop; then fill it with warm water.

[0129] Example 6, Method for preparing mixed asphalt

[0130] The difference from Example 5 is that in step S1, the raw materials are weighed according to the following parts by weight:

[0131] Asphalt 100

[0132] Yanshan Petrochemical SBS4303 4

[0133] LDPE 2

[0134] MAH-g-LDPE 1.0

[0135] Fatty acid-PEG ester / silica complex (Example 1) 5

[0136] Sulfur stabilizer 0.2

[0137] Hindered phenolic antioxidant 0.15

[0138] Phosphite antioxidant 0.05

[0139] Hindered amine UV inhibitor 0.10

[0140] 0.10g of ultraviolet absorber

[0141] Amine anti-stripping agent 0.20

[0142] 0.20g of silane coupling agent.

[0143] Example 7, Method for preparing mixed asphalt

[0144] The difference from Example 5 is that in step S1, the raw materials are weighed according to the following parts by weight:

[0145] Asphalt 100

[0146] Yanshan Petrochemical SBS4452 3

[0147] LDPE 1

[0148] MAH-g-LDPE 0.5

[0149] Fatty acid-PEG ester / silica composite (Example 2) 3

[0150] Sulfur stabilizer 0.1g.

[0151] Example 8, Method for preparing mixed asphalt

[0152] The difference from Example 5 is that in step S1, the raw materials are weighed according to the following parts by weight:

[0153] Asphalt 100

[0154] Yanshan Petrochemical SBS4452 4

[0155] LDPE 2

[0156] MAH-g-LDPE 1.0

[0157] Fatty acid-PEG ester / silica composite (Example 2) 5

[0158] Sulfur stabilizer 0.2

[0159] Hindered phenolic antioxidant 0.40

[0160] Phosphite antioxidant 0.10

[0161] Hindered amine UV inhibitor 0.25

[0162] UV absorber 0.25

[0163] Amine anti-stripping agent 0.40

[0164] Silane coupling agent 0.50.

[0165] Example 9, Method for preparing mixed asphalt

[0166] The difference from Example 5 is that the fatty acid-PEG ester / silica complex used in step S1 is derived from Example 3.

[0167] Example 10, Method for preparing mixed asphalt

[0168] The difference from Example 5 is that the fatty acid-PEG ester / silica complex used in step S1 is derived from Example 4.

[0169] Example 11, Method for preparing mixed asphalt

[0170] The difference from Example 5 is that the fatty acid-PEG ester / silica complex is not used in step S1.

[0171] Example 12, Method for preparing mixed asphalt

[0172] The difference from Example 5 is that MAH-g-LDPE is not used in step S1, but an equal amount of LDPE is used instead.

[0173] Example 13, Method for preparing mixed asphalt

[0174] The difference from Example 5 is that LDPE is not used in step S1, but an equal amount of MAH-g-LDPE is used instead.

[0175] Example 14, Method for preparing mixed asphalt

[0176] The difference from Example 5 is that the fatty acid-PEG ester / silica complex is not used in step S1; instead, an equal amount of behenic acid / silica complex is used.

[0177] The preparation method of behenic acid / silica composite is as follows:

[0178] S1: Take mesoporous silica, vacuum dry it at 120℃ for 6 hours to remove surface adsorbed water and activate silanol groups;

[0179] Pre-hydrolysis of silane coupling agent: Mix 1% by volume of (3-aminopropyl)triethoxysilane with silicon dioxide and stir magnetically for 0.5 hours at room temperature to allow for complete hydrolysis.

[0180] The pre-hydrolyzed solution is a mixture of deionized water and anhydrous ethanol, wherein the molar amount of deionized water is 1.5 times the total molar amount of ethoxy groups in (3-aminopropyl)triethoxysilane, and the volume of anhydrous ethanol is twice the volume of (3-aminopropyl)triethoxysilane.

[0181] The activated silica was dispersed in anhydrous isopropanol, and then the pre-hydrolyzed silane solution was slowly added dropwise; the mixture was refluxed and stirred at 80°C for 6 hours under nitrogen protection.

[0182] After the reaction was completed, the solid was collected by centrifugation, washed four times with anhydrous ethanol, and then washed once with acetone to completely remove the unreacted silane coupling agent. The obtained aminated silica was then dried in a vacuum oven at 60°C for later use.

[0183] S2: Mix behenic acid and the aminated silica obtained in S1 in a container at a mass ratio of 6:4;

[0184] Place the container in a 90°C oil bath and keep it in a vacuum drying oven or a device connected to a vacuum pump for 2 hours, stirring intermittently to allow behenic acid to fully penetrate into the pores of silica.

[0185] Remove the vacuum and cool the mixture to room temperature; the behenic acid will then re-solidify within the pores.

[0186] Slightly heat to 85°C and centrifuge to remove the small amount of excess behenic acid adhering to the surface of the silica particles, ensuring that all behenic acid is encapsulated in the pores; thus obtaining the behenic acid / silica composite.

[0187] Example 15, Method for preparing mixed asphalt

[0188] The difference from Example 5 is that the fatty acid-PEG ester / silica complex is not used in step S1; instead, an equal amount of PEG / silica complex is used.

[0189] Since dicarboxylated terminal PEG can undergo a crosslinking reaction with amino-modified silica, this example uses monocarboxylated terminal PEG (mPEG-COOH) for the experiment.

[0190] S1: Take mesoporous silica, vacuum dry it at 120℃ for 6 hours to remove surface adsorbed water and activate silanol groups;

[0191] Pre-hydrolysis of silane coupling agent: Mix 3% by volume of (3-aminopropyl)triethoxysilane with silica and stir magnetically for 0.5 hours at room temperature to allow for complete hydrolysis.

[0192] The pre-hydrolyzed solution is a mixture of deionized water and anhydrous ethanol, wherein the molar amount of deionized water is 1.5 times the total molar amount of ethoxy groups in (3-aminopropyl)triethoxysilane, and the volume of anhydrous ethanol is twice the volume of (3-aminopropyl)triethoxysilane.

[0193] The activated silica was dispersed in anhydrous isopropanol, and then the pre-hydrolyzed silane solution was slowly added dropwise; the mixture was refluxed and stirred at 80°C for 6 hours under nitrogen protection.

[0194] After the reaction was completed, the solid was collected by centrifugation, washed four times with anhydrous ethanol, and then washed once with acetone to completely remove the unreacted silane coupling agent. The obtained aminated silica was then dried in a vacuum oven at 60°C for later use.

[0195] S2: Mix mPEG-COOH and the aminated silica obtained in S1 in a container at a mass ratio of 6:4;

[0196] Place the container in an oil bath at 70°C and keep it in a vacuum drying oven or a device connected to a vacuum pump for 2 hours, stirring intermittently to allow mPEG-COOH to fully penetrate into the pores of silica.

[0197] Remove the vacuum and cool the mixture to room temperature; mPEG-COOH will then re-solidify within the pores.

[0198] Slightly heat to 60°C and centrifuge to remove the small amount of excess mPEG-COOH adhering to the surface of the silica particles, ensuring that all behenic acid is encapsulated in the pores; thus obtaining the PEG / silica composite.

[0199] Performance testing

[0200] The products obtained in Examples 5-15 above and commercially available asphalt were subjected to aging tests and DSR (Dynamic Shear Rheometer) rutting factor (G* / sinδ); the test methods are as follows:

[0201] The material was placed in a UV aging test chamber for UV aging experiments. The UV intensity in the UV aging test chamber was 1200 μW / cm². 2 The aging temperature was 60℃, and the aging time was 6 days. The softening point, penetration, and viscosity (at 60℃) of the asphalt before and after aging were then tested. The changes in softening point, penetration (at 60℃), and viscosity were calculated. The results are shown in Table 1.

[0202] Change rate = [(Performance index after aging - Performance index before aging) / Performance index before aging] * 100%;

[0203] The DSR (Dynamic Shear Rheometer) rutting factor (G* / sinδ) test was conducted according to the relevant records in the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering (JTG E20—2011)". The test temperature was 64℃. The complex shear modulus (G*) and phase angle (δ) were measured before and after aging, and then the rutting factor (G* / sinδ) was calculated.

[0204] The results are shown in Table 1.

[0205] Table 1

[0206]

[0207] Table 1 (continued)

[0208]

[0209] In Table 1, the softening point is in °C, the penetration is in dmm, the viscosity is in Pa·s, and the rutting factor is in kPa.

[0210] This invention encapsulates fatty acid-PEG ester phase change material (PCM) into aminated mesoporous silica to form a composite, and then uses it synergistically with an SBS / LDPE / MAH-g-LDPE polymer modification system to significantly improve the UV aging resistance and high-temperature rheological properties of asphalt (measured by the rutting factor G* / sinδ). Its core mechanism is as follows:

[0211] Temperature regulation mechanism: PCM undergoes a solid-liquid phase change when the ambient temperature fluctuates, absorbing or releasing a large amount of latent heat, which effectively inhibits the temperature rise of asphalt under sunlight, thereby slowing down the oxidative aging (volatilization, oxidation, hardening) and polymer degradation (SBS network breakage) caused by high temperature.

[0212] Physical reinforcement and adsorption mechanism: Mesoporous silica has a huge specific surface area and nanopore structure, which can not only serve as a stable carrier for PCM to prevent its leakage, but also adsorb light components in asphalt, increase the structural stability of asphalt and improve its high-temperature performance.

[0213] Chemical synergistic mechanism: MAH-g-LDPE acts as a compatibilizer, greatly improving the compatibility between non-polar polymers (SBS, LDPE) and polar bitumen matrix, forming a more stable, uniform, and robust three-dimensional polymer network. This network is the cornerstone of high performance.

[0214] Examples 5, 6, 7, and 8. They all used the complete formulation: fatty acid-PEG ester / silica complex (C22-PEG) and the complete polymer system (SBS+LDPE+MAH-g-LDPE).

[0215] Before aging, the asphalt exhibits a high softening point (74.5-77.0℃), high viscosity (1254-1523 Pa·s), and high rutting factor (4.71-5.92 kPa). This indicates that the initial polymer network structure is highly developed, endowing the asphalt with excellent high-temperature stability.

[0216] The change (%) of all performance indicators after aging is excellent.

[0217] The relatively small increases in softening point (6.0%-8.61%) and viscosity (26.71%-37.75%) indicate that the asphalt has only slightly hardened due to aging. The decrease in penetration (-10.20% to -20.37%) is controllable, maintaining good low-temperature performance. The increase in rutting factor (19.07%-19.59%) is much lower than that of the control group and the benchmark asphalt, and the absolute value after aging is the highest (5.64-7.08 kPa), indicating the strongest resistance to rutting.

[0218] The C22-PEG composite melts and absorbs heat when heated under UV light, effectively suppressing the rise in internal temperature of the asphalt sample. Temperature is a key factor in the aging reaction rate; the lower the temperature, the slower the rates of oxidation, volatilization, and polymer degradation. This is the core reason why all performance changes are well observed.

[0219] The presence of MAH-g-LDPE ensures that SBS and LDPE form a strong and uniform network with the asphalt. This network itself is elastic and resistant to deformation (high rutting factor). Even if some chain segments break during aging, the remaining network structure still provides strong support, thus resulting in slow performance degradation after aging.

[0220] Finally, the silica framework not only fixes the PCM, but also enhances the stiffness and stability of the asphalt.

[0221] Examples 7 & 8, compared to Examples 5 & 6, used SBS4452 with a higher S / B ratio (40:60) and a higher proportion of the compound / additive. A higher S / B ratio results in a higher content of polystyrene (S) hard segments, a stronger physical cross-linked network, and therefore higher initial rutting factor and viscosity, and better resistance to deformation.

[0222] However, since Examples 5 and 7 do not contain antioxidants, UV stabilizers, or other components, their performance after aging is worse than that of Examples 6 and 8.

[0223] Comparison of Examples 9 (C14-PEG), 10 (C18-PEG), and 5 (C22-PEG). Before aging: Performance was significantly worse than the C22 group; softening point, viscosity, and rutting factor were all lower.

[0224] The degree of change after aging is similar to or even slightly worse than that of group C22 (e.g., the increase in rutting factor is 19.63% / 20.32%), but the absolute value after aging is much lower than that of group C22 (e.g., rutting factor 3.84 / 4.56 vs 5.64).

[0225] This invention identifies the main problem as a mismatch in phase transition temperatures: myristic acid (C14) and stearic acid (C18) have significantly lower melting points than behenic acid (C22). For road asphalt, the operating temperature range is relatively high (up to 60-70°C in summer). C22-PEG's phase transition temperature is closer to this range, thus its temperature regulation function can be effectively activated at asphalt service temperatures. However, C14 and C18-PEG may melt at lower temperatures, failing to effectively absorb heat in the critical high-temperature zone, resulting in poorer temperature control.

[0226] Example 11: No fatty acid-PEG ester / silica composite; Example 12: No MAH-g-LDPE, replaced with an equal amount of LDPE; Example 13: No LDPE, replaced with an equal amount of MAH-g-LDPE.

[0227] Example 11 (without PCM compound): The performance was acceptable before aging (rutting factor 3.98), but the rutting factor increased by as much as 20.85% after aging; this indicates that without the temperature control protection of PCM, the asphalt under UV aging underwent more severe aging and hardening.

[0228] Example 12 (without MAH-g-LDPE): One of the worst performing groups. The absolute values ​​of all indicators before and after aging were extremely low; this indicates that without a compatibilizer, SBS and LDPE cannot be well compatible with asphalt, the polymer network is poorly formed or even not formed at all, and the effect of polymer modification is basically lost.

[0229] Example 13 (without LDPE): Performance is similar to 12, very poor. LDPE, as a plasticizer, mainly functions to improve the stiffness and viscosity of asphalt. Without LDPE, the system lacks sufficient rigid support, resulting in poor high-temperature performance.

[0230] Example 11 demonstrates the key role of the PCM complex in anti-aging, rather than providing the main mechanical properties. Examples 12 and 13 demonstrate that SBS, LDPE, and MAH-g-LDPE form a synergistic system, and none can be omitted. Removing the MAH-g-LDPE network prevents its formation; removing the LDPE network results in insufficient strength.

[0231] Example 14 used a simple behenic acid / silica composite; Example 15 used an mPEG-COOH / silica composite. These two groups exhibited the worst performance of all modified asphalts, even significantly worse than the missing groups (11, 12, 13). The rutting factors before aging were extremely low (2.31 and 1.91 kPa), indicating extremely poor high-temperature performance. The absolute values ​​remained the lowest after aging.

[0232] Example 14 (Simple Fatty Acid): Behenic acid is a small molecule. Although it can undergo a phase transition, it has poor compatibility with asphalt and may damage the colloidal structure of asphalt, acting as a negative "softener" or "lubricant," severely degrading the high-temperature mechanical properties of asphalt. Its weak temperature-controlling effect is far from enough to offset its damage to the asphalt structure. Example 15 (mPEG-COOH): mPEG-COOH is a linear polymer with only one carboxyl group at the chain end. It can only form point connections with aminated silica, unlike dicarboxyl-terminated PEG which can potentially form "cyclic" or "bridging" structures. This allows PEG molecules to move freely outside the silica channels. These free PEG molecules also severely soften asphalt, significantly reducing its high-temperature strength. Its temperature-controlling effect is again overshadowed by its negative effects. These two sets of negative examples precisely demonstrate the ingenuity of the molecular design of "fatty acid-PEG ester" in this invention: it combines the phase change properties of fatty acids with the flexibility and compatibility of PEG chains to form an ideal substance that has both phase change function and good compatibility with asphalt without damaging its structure.

[0233] Using commercially available No. 70 asphalt as a benchmark, its viscosity changed by as much as 101.43% and its rutting factor changed by as much as 51.67% after aging, which fully demonstrates the extreme sensitivity of unmodified asphalt to the environment (especially ultraviolet rays and heat).

[0234] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A type of asphalt with a high softening point temperature, characterized in that, The following components are included in parts by mass: Asphalt 100 Star-shaped SBS 3-4 LDPE 1-2 MAH-g-LDPE 0.5-1 Fatty acid-PEG complex / silica complex 3-5 Sulfur stabilizer 0.1-0.2; The preparation of the fatty acid-PEG complex / silica complex includes the following steps: S1: Select fatty acids with a carbon chain length ≥ 22 and PEG with dicarboxyl groups for termination; S2: Dissolve fatty acids and dicarboxylated PEG in anhydrous dichloromethane at a molar ratio of 1.05-1.1:1 in a container, and purge with an inert gas; add at least 0.1 mol of 4-dimethylaminopyridine and at least 1.05 mol of N,N'-dicyclohexylcarbodiimide; stir the reaction. S3: The reaction is complete when no more white precipitate is produced. Filter the solution and collect the filtrate. S4: Concentrate the filtrate and add anhydrous diethyl ether at ≤0℃ dropwise to precipitate the precipitate; S5: Collect the diethyl ether and wash it, then vacuum dry it to obtain the fatty acid-PEG complex; S6: Amide modification of silica surface using silane coupling agent; S7: Encapsulate the fatty acid-PEG complex into aminated silica to obtain a fatty acid-PEG complex / silica complex.

2. The asphalt with a high softening point temperature according to claim 1, characterized in that, In the preparation of the fatty acid-PEG complex / silica complex, the weight-average molecular weight of the dicarboxylated PEG is ≥4000 and the PDI is ≤1.

2.

3. The asphalt with a high softening point temperature according to claim 1, characterized in that, In the preparation of the fatty acid-PEG complex / silica complex, the silane coupling agent in step S6 is (3-aminopropyl)triethoxysilane, and its addition amount is 1-3% of the volume fraction of silica; the silica is mesoporous silica; the pore size of the mesoporous silica is ≥30nm.

4. The asphalt with a high softening point temperature according to claim 1, characterized in that, In the preparation of the fatty acid-PEG complex / silica complex, the mass ratio of fatty acid-PEG complex to aminated silica in step S7 is 6-7:3-4.

5. The asphalt with a high softening point temperature according to claim 1, characterized in that, In the preparation of the fatty acid-PEG complex / silica complex, step S7 involves mixing the fatty acid-PEG complex with aminated silica and placing the mixture in a container. The mixture is then heated to a temperature higher than the melting point of the fatty acid-PEG complex and kept in a vacuum for at least 2 hours to allow the fatty acid-PEG complex to melt and impregnate into the pores of the silica. The vacuum is then removed and the mixture is cooled. Finally, the fatty acid-PEG complex on the surface of the aminated silica is removed.

6. The asphalt with a high softening point temperature according to claim 1, characterized in that, It also includes 0.2-0.5 parts of antioxidants, including hindered phenolic antioxidants and phosphite antioxidants.

7. The asphalt with a high softening point temperature according to claim 1, characterized in that, It also includes 0.2-0.5 parts of UV protectant.

8. The asphalt with a high softening point temperature according to claim 1, characterized in that, It also includes 0.2-0.4 parts of amine anti-stripping agent and 0.2-0.5 parts of silane coupling agent.

9. The asphalt with a high softening point temperature according to claim 1, characterized in that, The styrene content in the star-shaped SBS is 30-40%.

10. The method for preparing asphalt with a high softening point temperature according to any one of claims 1-9, characterized in that, Includes the following steps: S1: Heat the asphalt to 160-180℃ under stirring conditions to maintain its fluidity; Then, under heat preservation, star-shaped SBS, LDPE, and MAH-g-LDPE are added by shearing until the polymer is dispersed and dissolved in the asphalt system. S2: Reduce the shear rate, add the fatty acid-PEG complex / silica complex and keep stirring for a period of time, then add the remaining components and stir until homogeneous; S3: Cool down to 160-170℃ and stop stirring. Seal and let it stand to swell and develop. Once development is complete, it becomes asphalt with a high softening point temperature.

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