High-performance PUSS PCM phase change self-temperature-regulating asphalt suitable for summer roads and a preparation method thereof

Abstract

The application provides a high-performance PUSSPCM phase change self-temperature regulating asphalt suitable for summer roads and a preparation method thereof. The high-performance PUSSPCM phase change self-temperature regulating asphalt comprises a polyurethane-based solid-solid phase change temperature regulating material and asphalt. Raw materials of the polyurethane-based solid-solid phase change temperature regulating material comprise polyethylene glycol with a molecular weight of 10000 and / or 20000, hexamethylene diisocyanate and a curing agent. The molar ratio of the hexamethylene diisocyanate to the polyethylene glycol is (4-8):1. The molar ratio of the hexamethylene diisocyanate to the curing agent is (2-4):1. The patent innovatively proposes a systematic solution from three dimensions of molecular structure design, interface compatibility regulation and particle size structure optimization to realize the engineering usability and high stability of the PUSSPCM self-temperature regulating asphalt.

Description

Technical Field

[0001] This application relates to the field of phase change temperature regulating materials technology, specifically to a high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces and its preparation method. Background Technology

[0002] Asphalt is a typical temperature-sensitive material, and its mechanical properties change significantly with temperature. In summer, the surface temperature of roads often exceeds 60°C, easily inducing high-temperature defects such as rutting, swelling, and bleeding, weakening the structural load-bearing capacity, shortening service life, and further exacerbating the urban heat island effect and reducing driving comfort. To improve the adaptability of road structures to the thermal environment, developing novel functional asphalt materials with active thermal regulation capabilities has become an important research direction in the field of road engineering.

[0003] Phase change self-regulating asphalt incorporates phase change materials with heat absorption and release capabilities, allowing it to absorb heat at high temperatures and release heat at low temperatures, thereby reducing internal temperature fluctuations and improving the thermal stability of roads. However, traditional solid-liquid phase change materials (such as polyethylene glycol, PEG) can experience liquid leakage during the phase change process, leading to a decrease in temperature regulation and damage to the adhesive structure of the asphalt. In high-temperature construction environments (160–180°C), they are more prone to softening or leakage, affecting material proportions, mixture performance, and long-term road service behavior. Therefore, improving the high-temperature leakage resistance of phase change materials in asphalt systems is a key prerequisite for the engineering application of phase change self-regulating asphalt.

[0004] Solid-solid phase change materials maintain a solid state throughout the phase change process, without liquid phase leakage, and exhibit higher morphological stability and engineering adaptability than solid-liquid phase change materials. Among them, PUSSPCM has become a core research direction in temperature-regulating asphalt in recent years due to its high latent heat of phase change, adjustable phase change temperature range, and good solid-state stability.

[0005] However, existing PUSSPCM self-regulating asphalt systems still face several key engineering bottlenecks: First, the systems mostly use PUSSPCM prepared from high-polarity isocyanates such as MDI and TDI as the temperature-regulating component, which has a high overall polarity and is significantly mismatched with the weakly polar petroleum asphalt. This results in poor dispersibility and weak interfacial adhesion in the asphalt matrix, making it prone to agglomeration and storage segregation, and making it difficult to form a stable and uniform phase structure. Second, the thermal stability of the PUSSPCM used in the current system is not compatible with the high-temperature construction conditions such as asphalt mixing and paving. At high temperatures of 160-180℃, there is still a risk of softening or flow, which can easily lead to the migration and leakage of the temperature-regulating component, thus limiting the large-scale application of PUSSPCM self-regulating asphalt in engineering projects.

[0006] Furthermore, in the PUSSPCM self-regulating asphalt system, significant sedimentation and segregation issues still exist when the temperature regulator is incorporated into the asphalt in solid particle form. Current practices often employ continuous particle size distribution, but it is difficult to construct a stable "skeleton-gap" structure in a high-viscosity asphalt environment. Coarse particles gradually settle under gravity, easily leading to stratification and a large difference in softening point, which in turn affects the component uniformity and long-term service stability of the self-regulating asphalt.

[0007] Currently, research on PUSSPCM phase change self-regulating asphalt is still in its early stages, with a limited number of published documents. Regarding particle size control, reference 1 (Duan Shiyu, Preparation and Properties of Bitumen-Modified Polyurethane Solid–Solid Phase Change Materials, Chang'an University, 2018.) and reference 2 (K. Wei, B. Ma, SY Duan, Preparation and Properties of Bitumen-Modified Polyurethane Solid–Solid Phase Change Materials, J Mater Civil Eng 31(8) (2019) 04019139.) limit the particle size of PUSSPCM asphalt temperature regulator to below 1.18 mm. Reference 3 (Liu Tao, Study on Temperature Regulation, Rheological Properties and Modification Mechanism of Polyurethane Solid–Solid Phase Change Modified Asphalt, Dalian Maritime University, 2023.) and reference 4 (Liu Tao, Guo Naisheng, Jin Xin, Hou Yilie, You Zhanping, Rheological Properties and Modification Mechanism of Polyurethane Solid–Solid Phase Change Material Modified Asphalt, China Journal of Highway and Transport 36(01) (2023)) further specify the particle size control. (16-26.) The particle size should be controlled below 1 mm. However, commonly used asphalt modifiers are mostly micron-sized or smaller, which differs from the particle size design of PUSSPCM self-regulating asphalt. For PUSSPCM phase change self-regulating asphalt, proper particle size control is crucial for its dispersibility, stability, and performance in asphalt. Therefore, reasonable particle size control is of great significance for improving the overall performance of PUSSPCM phase change self-regulating asphalt; however, there are currently no relevant reports.

[0008] Regarding compatibility improvement, references 1 and 3 systematically studied the compatibility differences between PUSSPCM with different molecular structures and asphalt, and selected a more suitable temperature-regulating agent molecular structure. However, the applicant found that it is difficult to significantly improve its compatibility with asphalt simply by adjusting the molecular structure, the fundamental reason being the significant polarity difference between the two. Insufficient compatibility not only weakens the dispersibility and interfacial bonding of PUSSPCM in asphalt, easily causing phase separation during storage or construction, thus affecting its road performance, but also limits the effective exertion of its temperature-regulating function, reducing the overall performance and engineering adaptability of the material. Therefore, effectively improving the compatibility between PUSSPCM and asphalt is the key to synergistically improving its storage stability, road performance, and temperature-regulating performance. Summary of the Invention

[0009] To address the aforementioned technical problems, this application provides a high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces and its preparation method. This patent innovatively proposes a systematic solution from three dimensions: molecular structure design (polarity matching and high-temperature solid-state stability), interfacial compatibility control (synergistic effect of dual-phase compatibilizers), and particle size structure optimization (constructing a stable packing skeleton across particle size distributions). This achieves the engineering usability and high stability of PUSSPCM self-regulating asphalt.

[0010] This application provides a high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces, comprising: a polyurethane-based solid-solid phase change temperature regulating material and asphalt; the raw materials of the polyurethane-based solid-solid phase change temperature regulating material include polyethylene glycol with a molecular weight of 10,000 and / or 20,000, hexamethylene diisocyanate, and a curing agent; the molar ratio of hexamethylene diisocyanate to polyethylene glycol is (4-8):1; the molar ratio of hexamethylene diisocyanate to curing agent is (2-4):1.

[0011] Furthermore, the mass ratio of polyurethane-based solid-solid phase change temperature regulating material to asphalt is (3-13):100.

[0012] Preferably, the mass ratio of polyurethane-based solid-solid phase change temperature regulating material to asphalt is (8-10):100.

[0013] Furthermore, when the molecular weight of polyethylene glycol is 10,000, the molar ratio of hexamethylene diisocyanate to polyethylene glycol is (4-6):1;

[0014] When the molecular weight of polyethylene glycol is 20,000, the molar ratio of hexamethylene diisocyanate to polyethylene glycol is (6-8):1.

[0015] Furthermore, the curing agent is one or more of diethyltoluenediamine, 4,4'-diaminodiphenylmethane, and 3,3'-dichloro-4,4'-diphenylmethanediamine (MOCA).

[0016] Furthermore, the curing agent is 3,3'-dichloro-4,4'-diphenylmethanediamine.

[0017] Furthermore, the particle size of the polyurethane-based solid-solid phase change temperature regulating material is ≤0.60 mm.

[0018] Furthermore, the particle size of the polyurethane-based solid-solid phase change temperature regulating material includes a first particle size and a second particle size; the particle size of the first particle size is ≤0.075mm; the particle size of the second particle size is 0.15-0.60mm; the mass ratio of the first particle size to the second particle size is (6-8):(1-3).

[0019] Furthermore, the particle size of the second particle size fraction is 0.15-0.30 mm; the mass ratio of the particles of the first particle size fraction to the particles of the second particle size fraction is 7:2.

[0020] The particle size mentioned in this application refers to the average particle size, specifically the median particle size D50, which means that 50% of the particles in the sample are smaller than this value and 50% are larger than this value.

[0021] Furthermore, it also includes a compatibilizer, which is one or more of maleic anhydride and 3-aminopropyltriethoxysilane;

[0022] The mass ratio of the compatibilizer to the asphalt is (1-3):100.

[0023] Furthermore, the compatibilizer is a composition of maleic anhydride and 3-aminopropyltriethoxysilane, wherein the mass ratio of maleic anhydride to 3-aminopropyltriethoxysilane is (6-8):(2-4).

[0024] Preferably, the mass ratio of maleic anhydride to 3-aminopropyltriethoxysilane is 7:3.

[0025] This application provides a method for preparing high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces, comprising the following steps:

[0026] (1) Polyethylene glycol is dissolved in a solvent to obtain a polyethylene glycol solution. Under a nitrogen protective atmosphere, hexamethylene diisocyanate is added to the polyethylene glycol solution at 75-85℃ and stirred for 5-120 min. Then, a curing agent is added and the reaction continues for 5-180 min. The resulting mixture is then placed in a vacuum environment to remove the solvent, thus obtaining a polyurethane-based solid-solid phase change temperature-regulating material.

[0027] (2) Heat the asphalt to 160-180℃, add polyurethane-based solid phase change temperature regulating material and disperse it to obtain PUSSPCM phase change self-temperature regulating asphalt.

[0028] Furthermore, when a compatibilizer is added to the system, the preparation method of high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces according to this application includes the following steps:

[0029] (1) Polyethylene glycol is dissolved in a solvent to obtain a polyethylene glycol solution. Under a nitrogen protective atmosphere, hexamethylene diisocyanate is added to the polyethylene glycol solution at 75-85℃ and stirred for 5-120 min. Then, a curing agent is added and the reaction continues for 5-180 min. The resulting mixture is then placed in a vacuum environment to remove the solvent, thus obtaining a polyurethane-based solid-solid phase change temperature-regulating material.

[0030] (2) Heat the asphalt to 160-180℃, add compatibilizer at 200-1000rpm and stir for 5-10min to fully disperse it; after adding polyurethane-based solid phase change temperature regulating material, increase the speed to 1500-3000rpm and disperse to obtain PUSSPCM phase change self-regulating asphalt.

[0031] Furthermore, when compatibilizers of different particle sizes are added to the system, this application provides a method for preparing high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces, comprising the following steps:

[0032] (1) Polyethylene glycol is dissolved in a solvent to obtain a polyethylene glycol solution. Under a nitrogen protective atmosphere, hexamethylene diisocyanate is added to the polyethylene glycol solution at 75-85℃ and stirred for 5-120 min. Then, a curing agent is added and the reaction continues for 5-180 min. The resulting mixture is then placed in a vacuum environment to remove the solvent, thus obtaining a polyurethane-based solid-solid phase change temperature-regulating material.

[0033] (2) Heat the asphalt to 160-180℃, add compatibilizer at 200-1000rpm and stir for 5-10min to fully disperse it; then add the second-grade polyurethane-based solid phase change temperature regulating material and stir for 2-5min to form a stable skeleton. Then add the first-grade polyurethane-based solid phase change temperature regulating material, and then increase the speed to 1500-3000rpm and continue to disperse for 10-30min. After dispersion, PUSSPCM phase change self-regulating asphalt is obtained.

[0034] The beneficial effects of this application are as follows:

[0035] 1. This application addresses the problems of poor compatibility and high-temperature leakage between traditional polyurethane-based solid-solid phase change materials and asphalt through material selection and structural design, focusing on polarity matching and crosslinking density. This application utilizes linear aliphatic HDI, whose molecular structure does not contain benzene rings, resulting in significantly reduced polarity and a polarity closer to that of asphalt, thereby improving interfacial compatibility and enhancing the uniformity of asphalt mixtures. By controlling the molar ratio of HDI to polyethylene glycol and introducing a curing agent, a highly crosslinked three-dimensional network is formed. The high HDI content provides numerous hard segments and crosslinking points, firmly binding the PEG soft segments within the network, achieving solid-solid phase change characteristics. The highly crosslinked design ensures that the material remains completely solid and leak-free up to 185°C.

[0036] 2. This application, through precise design of the particle size distribution of PUSSPCM, physically constructs a stable suspension system, fundamentally solving the sedimentation and segregation problems of phase change materials in high-viscosity asphalt caused by density differences and gravity. The second-order particles of this application, acting as skeleton particles, can form a loose yet strong three-dimensional network when close together, significantly slowing down the overall settling rate. Their moderate particle size ensures good interfacial bonding with asphalt, preventing them from completely detaching from the asphalt phase and settling rapidly on their own. The first-order particles of this application, acting as gap fillers and stabilizers, effectively fill the gaps between skeleton particles. This dense filling significantly increases the contact points and friction between particles, making the skeleton structure more stable and the overall packing denser, greatly restricting the sliding path and degrees of freedom of coarse particles. The extremely fine particles have a huge specific surface area, strongly adsorbing lightweight components in the asphalt to form a stable, gelled interfacial layer, significantly increasing the apparent viscosity of the continuous asphalt phase, thereby increasing the viscous resistance to the movement of any particles.

[0037] 3. A compatibilizer is added to the system. Maleic anhydride (MAH) acts as a chemical bridging agent at the asphalt-PUSSPCM interface. One end of MAH is anchored to the PUSSPCM surface via covalent bonds or strong hydrogen bonds, while the other end is deeply embedded into the continuous asphalt phase through chemical reactions and physical interactions, greatly enhancing the interfacial adhesion between PUSSPCM and asphalt. MAH contains highly active anhydride rings and carbon-carbon double bonds. At the high temperature of asphalt mixing, the anhydride groups of MAH can react with trace amounts of -NCO or -NH2 groups that may remain at the ends of the PUSSPCM molecular chains to generate imide or amide bonds, thereby chemically grafting MAH molecules onto the surface of PUSSPCM particles via covalent bonds. The carbon-carbon double bonds of MAH can undergo cycloaddition or free radical reactions with the aromatic rings abundant in asphalt. The polar anhydride / hydroxyl portion of MAH has strong physical adsorption and hydrogen bonding with polar components such as gums and asphaltenes in asphalt; and the non-polar olefin structure in MAH has excellent compatibility with the oil content of asphalt.

[0038] 4. In 3-aminopropyltriethoxysilane, the amino group is the organic reaction end, which can react with the -NCO group of PUSSPCM to form a urea bond. The triethoxysilane in 3-aminopropyltriethoxysilane is the inorganic reaction end. Under the high temperature and trace amount of moisture in the asphalt mixing process, the ethoxy group is hydrolyzed to generate highly active silanols. The silanols can condense with each other to form Si-OSI covalent bonds. Attached Figure Description

[0039] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0040] Figure 1 FTIR plots of PUSSPCM and its raw materials;

[0041] Figure 2 The DSC curve of PUSSPCM;

[0042] Figure 3 The TGA curve for PUSSPCM;

[0043] Figure 4 The results of the leak resistance test of PUSSPCM at 190℃;

[0044] Figure 5 The heating curve of PUSSPCM phase change self-regulating asphalt.

[0045] Figure 6 Fluorescence micrograph of PUSSPCM phase change self-regulating temperature bitumen. Detailed Implementation

[0046] Unless otherwise specified, the reagents and instruments used in the following examples are all commercially available products.

[0047] The preparation method of the polyurethane-based solid-solid phase change temperature-regulating material of this application can use solution polymerization (using solvent, homogeneous reaction) and bulk melt polymerization (solvent-free, direct heating reaction) and other preparation processes. In order to demonstrate the experimental effect, the specific embodiments of this application all use solution polymerization to conduct experiments.

[0048] The asphalt raw materials used in this application are conventional asphalt raw materials such as road petroleum asphalt, SBS modified asphalt, and high viscosity modified asphalt. In order to better demonstrate the test results, the asphalt raw material used in the specific implementation of this application is commercially available No. 70 road petroleum asphalt.

[0049] Example 1

[0050] This embodiment provides a high-performance PUSSPCM phase change self-regulating temperature asphalt suitable for summer road surfaces. The raw materials include: asphalt, polyethylene glycol with a molecular weight of 10,000, hexamethylene diisocyanate, and diethyltoluene diamine, wherein the molar ratio of hexamethylene diisocyanate to polyethylene glycol is 4:1, and the molar ratio of hexamethylene diisocyanate to diethyltoluene diamine is 2:1.

[0051] The preparation method includes the following steps:

[0052] (1) Polyethylene glycol is dissolved in DMF solvent to prepare a polyethylene glycol solution with a solvent-to-polyethylene glycol mass ratio of 5:1; under a nitrogen protective atmosphere, hexamethylene diisocyanate is added to the polyethylene glycol solution at 75°C and stirred for 120 min, then a curing agent is added and the reaction continues for 5 min, and then the resulting mixture is placed in a vacuum environment to remove the solvent, thus obtaining a polyurethane-based solid-solid phase change temperature-regulating material;

[0053] (2) Heat the asphalt to 160°C, add the pulverized and ground polyurethane-based solid phase change temperature regulating material with an average particle size of 0.6 mm, disperse it to obtain PUSSPCM phase change self-regulating asphalt, and the mass ratio of polyurethane-based solid phase change temperature regulating material to asphalt is 3:100.

[0054] Example 2

[0055] This embodiment provides a high-performance PUSSPCM phase change self-regulating temperature asphalt suitable for summer road surfaces. The raw materials include: asphalt, polyethylene glycol with a molecular weight of 10,000, hexamethylene diisocyanate, and 4,4'-diaminodiphenylmethane, wherein the molar ratio of hexamethylene diisocyanate to polyethylene glycol is 8:1; and the molar ratio of hexamethylene diisocyanate to 4,4'-diaminodiphenylmethane is 4:1.

[0056] The preparation method includes the following steps:

[0057] (1) Polyethylene glycol was dissolved in NMP solvent to prepare a polyethylene glycol solution with a solvent-to-polyethylene glycol mass ratio of 10:1. Under a nitrogen protective atmosphere, hexamethylene diisocyanate was added to the polyethylene glycol solution at 85°C and stirred for 5 min. Then, a curing agent was added and the reaction continued for 180 min. The resulting mixture was then placed in a vacuum environment to remove the solvent, thus obtaining a polyurethane-based solid-solid phase change temperature-regulating material.

[0058] (2) Heat the asphalt to 180°C, add the pulverized and ground polyurethane-based solid phase change temperature regulating material with an average particle size of 0.3 mm, disperse it to obtain PUSSPCM phase change self-regulating asphalt, and the mass ratio of polyurethane-based solid phase change temperature regulating material to asphalt is 13:100.

[0059] Example 3

[0060] This embodiment provides a high-performance PUSSPCM phase change self-regulating temperature asphalt suitable for summer road surfaces. The raw materials include: asphalt, polyethylene glycol with a molecular weight of 10,000, hexamethylene diisocyanate, and MOCA, wherein the molar ratio of hexamethylene diisocyanate to polyethylene glycol is 6:1; and the molar ratio of hexamethylene diisocyanate to MOCA is 3:1.

[0061] The preparation method includes the following steps:

[0062] (1) Polyethylene glycol is dissolved in toluene solvent to prepare a polyethylene glycol solution with a solvent-to-polyethylene glycol mass ratio of 8:1; under a nitrogen protective atmosphere, hexamethylene diisocyanate is added to the polyethylene glycol solution at 80°C and stirred for 20 min, then a curing agent is added and the reaction continues for 30 min, and then the resulting mixture is placed in a vacuum environment to remove the solvent, thus obtaining a polyurethane-based solid-solid phase change temperature-regulating material;

[0063] (2) Heat the asphalt to 170°C, add the pulverized and ground polyurethane-based solid phase change temperature regulating material with an average particle size of 0.1 mm, disperse it to obtain PUSSPCM phase change self-regulating asphalt, and the mass ratio of polyurethane-based solid phase change temperature regulating material to asphalt is 5:100.

[0064] Example 4

[0065] This embodiment provides a high-performance PUSSPCM phase change self-regulating temperature asphalt suitable for summer road surfaces. The raw materials include: asphalt, polyethylene glycol with a molecular weight of 20,000, hexamethylene diisocyanate, and 4,4'-diaminodiphenylmethane, wherein the molar ratio of hexamethylene diisocyanate to polyethylene glycol is 8:1; and the molar ratio of hexamethylene diisocyanate to 4,4'-diaminodiphenylmethane is 2:1.

[0066] The preparation method includes the following steps:

[0067] (1) Polyethylene glycol is dissolved in DMF solvent to prepare a polyethylene glycol solution with a solvent-to-polyethylene glycol mass ratio of 10:1; under a nitrogen protective atmosphere, hexamethylene diisocyanate is added to the polyethylene glycol solution at 85°C and stirred for 60 min, then a curing agent is added and the reaction continues for 60 min, and then the resulting mixture is placed in a vacuum environment to remove the solvent, thus obtaining a polyurethane-based solid-solid phase change temperature-regulating material;

[0068] (2) Heat the asphalt to 180°C, add the pulverized and ground polyurethane-based solid phase change temperature regulating material with an average particle size of 0.15 mm, disperse it to obtain PUSSPCM phase change self-regulating asphalt, and the mass ratio of polyurethane-based solid phase change temperature regulating material to asphalt is 10:100.

[0069] Example 5

[0070] This embodiment provides a high-performance PUSSPCM phase change self-regulating temperature asphalt suitable for summer road surfaces. The raw materials include: asphalt, polyethylene glycol with a molecular weight of 20,000, hexamethylene diisocyanate, and diethyltoluene diamine, wherein the molar ratio of hexamethylene diisocyanate to polyethylene glycol is 4:1; and the molar ratio of hexamethylene diisocyanate to diethyltoluene diamine is 4:1.

[0071] The preparation method includes the following steps:

[0072] (1) Polyethylene glycol is dissolved in DMF solvent to prepare a polyethylene glycol solution with a solvent-to-polyethylene glycol mass ratio of 5:1; under a nitrogen protective atmosphere, hexamethylene diisocyanate is added to the polyethylene glycol solution at 75°C and stirred for 100 min, then a curing agent is added and the reaction continues for 100 min, and the resulting mixture is placed in a vacuum environment to remove the solvent, thus obtaining a polyurethane-based solid-solid phase change temperature-regulating material;

[0073] (2) Heat the asphalt to 160°C, add the pulverized and ground polyurethane-based solid phase change temperature regulating material with an average particle size of 0.075 mm, disperse it to obtain PUSSPCM phase change self-regulating asphalt, and the mass ratio of polyurethane-based solid phase change temperature regulating material to asphalt is 5:100.

[0074] Example 6

[0075] This embodiment provides a high-performance PUSSPCM phase change self-regulating temperature asphalt suitable for summer road surfaces. The raw materials include: asphalt, polyethylene glycol with a molecular weight of 20,000, hexamethylene diisocyanate, and MOCA, wherein the molar ratio of hexamethylene diisocyanate to polyethylene glycol is 6:1; and the molar ratio of hexamethylene diisocyanate to MOCA is 3:1.

[0076] The preparation method includes the following steps:

[0077] (1) Polyethylene glycol is dissolved in DMF solvent to prepare a polyethylene glycol solution with a solvent-to-polyethylene glycol mass ratio of 6:1. Under a nitrogen protective atmosphere, hexamethylene diisocyanate is added to the polyethylene glycol solution at 80°C and stirred for 60 min. Then, a curing agent is added and the reaction continues for 40 min. The resulting mixture is then placed in a vacuum environment to remove the solvent, thus obtaining a polyurethane-based solid-solid phase change temperature-regulating material.

[0078] (2) Heat the asphalt to 170°C, add the pulverized and ground polyurethane-based solid phase change temperature regulating material with an average particle size of 0.05 mm, disperse it to obtain PUSSPCM phase change self-regulating asphalt, and the mass ratio of polyurethane-based solid phase change temperature regulating material to asphalt is 8:100.

[0079] Example 7

[0080] The only difference from Example 3 is step (2) of the preparation method:

[0081] Asphalt was heated to 170°C. First, a second-sized polyurethane-based solid-solid phase change temperature-regulating material (average particle size of 0.6 mm) was added and stirred for 5 minutes. Then, a first-sized polyurethane-based solid-solid phase change temperature-regulating material (average particle size of 0.075 mm) was added and dispersed to obtain PUSSPCM phase change self-regulating asphalt. The mass ratio of the first-sized particles to the second-sized particles was 6:1, and the mass ratio of the polyurethane-based solid-solid phase change temperature-regulating material to asphalt was 5:100.

[0082] Example 8

[0083] The only difference from Example 3 is step (2) of the preparation method:

[0084] Asphalt was heated to 160°C. First, a second-sized polyurethane-based solid-solid phase change temperature-regulating material (average particle size of 0.15 mm) was added and stirred for 5 minutes. Then, a first-sized polyurethane-based solid-solid phase change temperature-regulating material (average particle size of 0.05 mm) was added and dispersed to obtain PUSSPCM phase change self-regulating asphalt. The mass ratio of the first-sized particles to the second-sized particles was 8:3, and the mass ratio of the polyurethane-based solid-solid phase change temperature-regulating material to asphalt was 5:100.

[0085] Example 9

[0086] The only difference from Example 3 is step (2) of the preparation method:

[0087] Asphalt was heated to 160°C. First, a second-sized polyurethane-based solid-solid phase change temperature-regulating material (average particle size of 0.3 mm) was added and stirred for 5 minutes. Then, a first-sized polyurethane-based solid-solid phase change temperature-regulating material (average particle size of 0.035 mm) was added and dispersed to obtain PUSSPCM phase change self-regulating asphalt. The mass ratio of the first-sized particles to the second-sized particles was 7:2, and the mass ratio of the polyurethane-based solid-solid phase change temperature-regulating material to asphalt was 5:100.

[0088] Example 10

[0089] Based on Example 6, maleic anhydride was added as a compatibilizer, with a mass ratio of compatibilizer to asphalt of 1:100; the preparation method was the same as in Example 6 in step (1), and step (2) was as follows:

[0090] Asphalt was heated to 170°C, a compatibilizer was added at 200 rpm and stirred for 10 min, and then a pulverized and ground polyurethane-based solid phase change temperature regulating material with an average particle size of 0.05 mm was added. The rotation speed was increased to 1500 rpm and dispersed for 10 min to obtain PUSSPCM phase change self-regulating asphalt. The mass ratio of polyurethane-based solid phase change temperature regulating material to asphalt was 8:100.

[0091] Example 11

[0092] The difference from Example 10 is that the compatibilizer is 3-aminopropyltriethoxysilane.

[0093] Example 12

[0094] The difference from Example 10 is that the compatibilizer is a composition of maleic anhydride and 3-aminopropyltriethoxysilane, with a mass ratio of maleic anhydride to 3-aminopropyltriethoxysilane of 6:2.

[0095] Example 13

[0096] In Example 9, a compatibilizer was added to the system. The compatibilizer was a composition of maleic anhydride and 3-aminopropyltriethoxysilane, with a mass ratio of maleic anhydride to 3-aminopropyltriethoxysilane of 7:3.

[0097] Step (2) of the preparation method:

[0098] Asphalt was heated to 160℃, and a compatibilizer was added at 1000 rpm and stirred for 5 min. First, the second particle size (average particle size of 0.3 mm) of polyurethane-based solid-solid phase change temperature regulating material was added and stirred for 5 min. Then, the first particle size (average particle size of 0.035 mm) of polyurethane-based solid-solid phase change temperature regulating material was added. The rotation speed was increased to 3000 rpm and dispersed for 30 min to obtain PUSSPCM phase change self-regulating asphalt. The mass ratio of the first particle size to the second particle size was 7:3, and the mass ratio of the polyurethane-based solid-solid phase change temperature regulating material to asphalt was 5:100.

[0099] Comparative Example 1

[0100] The difference from Example 3 is that the molecular weight of the polyethylene glycol is 8000.

[0101] Comparative Example 2

[0102] The difference from Example 3 is that the isocyanate is MDI.

[0103] Comparative Example 3

[0104] The difference from Example 3 is that the isocyanate is hexamethylene diisocyanate and polyethylene glycol in a molar ratio of 2:1.

[0105] Characterization:

[0106] 1. Fourier transform infrared spectroscopy (FTIR) was performed on the polyurethane-based solid-solid phase change temperature-regulating materials obtained in Examples 3 and 6;

[0107] like Figure 1 As shown, in the infrared spectrum of PUSSPCM, the characteristic absorption peaks of the corresponding active functional groups in polyethylene glycol (PEG), hexamethylene diisocyanate (HDI), and MOCA (located at 3449 cm⁻¹, respectively) are... - ¹、2256cm - ¹ and 3441cm - ¹) All of these functional groups have disappeared, indicating that they were completely consumed during the reaction. Meanwhile, the infrared spectrum of PUSSPCM at 1721 cm⁻¹... - ¹ and 1640cm - A new weak absorption peak appears at ¹, attributed to the stretching vibrations of the C=O bonds in the –NHCOO– and –NHCONH– structures, respectively. Furthermore, at 3307 cm⁻¹… - ¹ Stretching vibration peaks of the –NH groups in the –NHCOO– and –NHCONH– structures can also be observed. The –NHCOO– structure is formed by the reaction of the –NCO group in HDI with the –OH group in PEG, while the –NHCONH– structure originates from the reaction of the –NCO group in the prepolymer with the –NH group in MOCA. Therefore, the above infrared spectral characteristics clearly indicate that PEG, HDI, and MOCA have successfully undergone a chemical reaction, thus confirming the successful synthesis of PUSSPCM.

[0108] 2. Differential scanning calorimetry (DSC) was performed on the polyurethane-based solid-solid phase change temperature-regulating materials obtained in Examples 3, 4, and 6.

[0109] like Figure 2 As shown, PUSSPCM exhibits stable phase transition behavior during heating, with its phase transition temperature concentrated in the range of 50–52°C. This effectively matches the high-temperature service environment of pavement asphalt materials during summer daytime, where the asphalt temperature typically reaches above 60°C. Simultaneously, during cooling, the phase transition temperature of PUSSPCM remains between 36 and 41°C, allowing it to release stored latent heat when the asphalt temperature drops below 35°C at night in summer. Furthermore, PUSSPCM possesses considerable latent heat of phase transition (99–112 J / g), ensuring continuous and effective thermal regulation of pavement asphalt materials.

[0110] It can be seen that the synthesized PUSSPCM closely matches the actual temperature change range of pavement asphalt materials in summer during both the heating and cooling stages, indicating that it can actively regulate the temperature of pavement asphalt through phase change heat storage / release behavior, thus possessing potential engineering value for pavement asphalt temperature control.

[0111] 3. Thermogravimetric analysis (TGA) was performed on the polyurethane-based solid-solid phase change temperature-regulating materials obtained in Examples 1, 3, and 6.

[0112] 4. For example Figure 3 As shown, the synthesized PUSSPCM exhibited almost no mass loss below 200℃, indicating good thermal stability during the high-temperature preparation process of modified asphalt and under high-temperature construction conditions (<190℃) for asphalt pavement, meeting the requirements for heat resistance in practical engineering applications. Leakage resistance and surface morphology tests were conducted on the polyurethane-based solid-solid phase change temperature-regulating materials obtained in Examples 1-6 and Comparative Examples 1-3.

[0113] Place the sample on highly absorbent filter paper and incubate at 190°C for 2 hours, then observe the water absorption of the filter paper. If the filter paper absorbs water, it indicates a material leak; if it does not absorb water, it indicates no leak.

[0114] like Figure 4 As shown, the PUSSPCMs prepared in Examples 1-6 remained completely solid at 190°C, with no leakage observed. Furthermore, the sample surfaces were smooth and uniform, and the structures were intact, indicating that the materials possess good morphological and thermal stability at high temperatures. Simultaneously, the uniform surface morphology also suggests that the internal reaction of the system was relatively complete and uniform, forming a stable cross-linked network structure.

[0115] In contrast, Comparative Example 1 and Comparative Example 3 both showed obvious leakage at 190℃, indicating that their high-temperature stability was insufficient; although Comparative Example 2 did not show obvious leakage, its surface color was uneven and its morphology was rough, reflecting that the system reaction was uneven and the structural integrity was poor.

[0116] 5. High-temperature environment simulation tests were conducted on the PUSSPCM phase change self-regulating asphalt obtained in Examples 3, 9, and 13 to verify the temperature regulation effect;

[0117] PUSSPCM phase change self-regulating temperature asphalt samples with built-in PT-100 temperature sensors were placed in a 60℃ environmental chamber. The internal temperature of the asphalt was monitored and recorded in real time over time using a paperless recorder. The test results are as follows: Figure 5As shown in Table 1, the results indicate that when the internal temperature of the sample rises to 55°C and 60°C, Example 13 requires the longest time, followed by Example 9 and Example 3. Therefore, Examples 9 and 13 have a temperature-retarding effect, with Example 13 being the most significant.

[0118] Table 1. Temperature regulation effect of PUSSPCM self-regulating asphalt

[0119]

[0120] 6. Softening point difference tests were conducted on the PUSSPCM phase change self-regulating asphalt obtained in Examples 3, 6, 7-13, and Comparative Examples 1-3; the polymer-modified asphalt segregation test was performed in accordance with the standard "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011).

[0121] Table 2. Segregation test results of PUSSPCM self-regulating asphalt

[0122]

[0123] The difference in softening point is a key indicator for evaluating the storage stability of modified asphalt. The smaller the difference, the more uniformly the PUSSPCM is dispersed in the asphalt, the better its compatibility, and the less likely it is to undergo phase separation and segregation.

[0124] As shown in Table 2, the dual-particle-size compound system is superior to the single-particle-size system. Examples 7-9, which use dual-particle-size compound systems, show significantly better softening point differences than Example 3. Examples 10-13 demonstrate that the addition of a compatibilizer significantly improves the softening point difference, with Examples 12 and 13 showing particularly effective compatibilizer combinations that improve asphalt stability. Comparative Example 1 uses low-molecular-weight polyethylene glycol, which may result in substandard phase transition enthalpy and material properties. Furthermore, the higher polarity of the low-molecular-weight PEG segments leads to poorer compatibility with asphalt. Comparative Example 2 uses MDI instead of HDI, resulting in decreased compatibility with asphalt. Comparative Example 3 has an excessively low isocyanate ratio, leading to insufficient solid-state stability of the PUSSPCM. The material softens and becomes viscous in the high-temperature environment of asphalt, exacerbating segregation.

[0125] 7. The microstructure of the PUSSPCM phase change self-regulating temperature asphalt obtained in Examples 3, 6, 9, 10, 12, 13 and Comparative Examples 1-3 was tested using a fluorescence microscope.

[0126] like Figure 6As shown, in Example 10, the dispersibility of PUSSPCM in asphalt was significantly improved after the addition of a single compatibilizer; while in Example 12, the dispersibility of PUSSPCM in asphalt was further improved when a compound compatibilizer was used, indicating that the compound compatibilizer has a more significant effect on improving the compatibility of PUSSPCM with the asphalt matrix.

[0127] Example 9 uses different particle size distributions for PUSSPCM, which is beneficial to the dispersibility of PUSSPCM in asphalt; Example 13 further uses a compatibilizer to further improve the dispersibility of PUSSPCM in asphalt.

[0128] In Comparative Examples 1 and 2, altering the molecular weight of polyethylene glycol and the isocyanate during the synthesis of PUSSPCM significantly reduced the dispersibility of PUSSPCM in asphalt.

[0129] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0130] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces, characterized in that, include: Polyurethane-based solid-solid phase change temperature regulating materials, asphalt, compatibilizers; The raw materials of the polyurethane-based solid-solid phase change temperature-regulating material include polyethylene glycol with a molecular weight of 10,000 and / or 20,000, hexamethylene diisocyanate, and a curing agent; the molar ratio of hexamethylene diisocyanate to polyethylene glycol is (4-8):1; the molar ratio of hexamethylene diisocyanate to curing agent is (2-4):1; the particle size of the polyurethane-based solid-solid phase change temperature-regulating material is <0.60 mm; the compatibilizer is one or more of maleic anhydride and 3-aminopropyltriethoxysilane; the mass ratio of the compatibilizer to asphalt is (1-3):

100.

2. The high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces according to claim 1, characterized in that, When the molecular weight of polyethylene glycol is 10,000, the molar ratio of hexamethylene diisocyanate to polyethylene glycol is (4-6):1; When the molecular weight of polyethylene glycol is 20,000, the molar ratio of hexamethylene diisocyanate to polyethylene glycol is (6-8):

1.

3. The high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces according to claim 1, characterized in that, The curing agent is one or more of diethyltoluenediamine, 4,4'-diaminodiphenylmethane, and 3,3'-dichloro-4,4'-diphenylmethanediamine.

4. The high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces according to claim 1, characterized in that, The particle size of the polyurethane-based solid-solid phase change temperature regulating material includes a first particle size and a second particle size; the particle size of the first particle size is ≤0.075mm; the particle size of the second particle size is 0.15-0.60mm; the mass ratio of the first particle size to the second particle size is (6-8):(1-3).

5. The high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces according to claim 4, characterized in that, The particle size of the second particle size fraction is 0.15-0.30 mm; the mass ratio of the particles of the first particle size fraction to the particles of the second particle size fraction is 7:

2.

6. The high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces according to claim 1, characterized in that, The compatibilizer is a composition of maleic anhydride and 3-aminopropyltriethoxysilane, wherein the mass ratio of maleic anhydride to 3-aminopropyltriethoxysilane is (6-8):(2-4).

7. The high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces according to claim 1, characterized in that, The mass ratio of the polyurethane-based solid-solid phase change temperature regulating material to asphalt is (3-13):

100.

8. The method for preparing high-performance PUSSPCM phase change self-regulating asphalt suitable for summer road surfaces according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Polyethylene glycol is dissolved in a solvent to obtain a polyethylene glycol solution. Under a nitrogen protective atmosphere, hexamethylene diisocyanate is added to the polyethylene glycol solution at 75-85℃ and stirred for 5-120 min. Then, a curing agent is added and the reaction continues for 5-180 min. The resulting mixture is then placed in a vacuum environment to remove the solvent, thus obtaining a polyurethane-based solid-solid phase change temperature-regulating material. (2) Heat the asphalt to 160-180℃, add compatibilizer at 200-1000rpm and stir for 5-10min to fully disperse it; after adding polyurethane-based solid phase change temperature regulating material, increase the speed to 1500-3000rpm and disperse to obtain PUSSPCM phase change self-regulating asphalt.

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