A method for preparing a waste polyethylene terephthalate polyol and a high-performance polyurethane modified asphalt thereof

Abstract

The application discloses a preparation method of waste polyethylene terephthalate polyol and high-performance polyurethane modified asphalt, and belongs to the technical field of road engineering materials. The waste polyethylene terephthalate polyol is prepared from waste polyethylene terephthalate plastic bottles, a degradation agent and a catalyst according to a mass ratio of 1: (0.5-3.5) : (0.015-0.025), is prepared by cutting and dehydration, and is mixed by sectional heating, has a high conversion rate and does not need complicated post-treatment. The polyol is used to synthesize polyurethane with polyether polyol, polyisocyanate and a crosslinking agent according to specific molar ratios, and then is mixed with 70# base asphalt according to a certain proportion, is preheated, stirred and developed to obtain high-performance modified asphalt. The product has excellent high and low temperature performance, elastic recovery and fatigue resistance, is suitable for high-grade roads, can reduce the dependence on petroleum resources, realizes high-value utilization of waste PET, is environmentally friendly and low in cost.

Description

Technical Field

[0001] This invention belongs to the field of road engineering materials technology, and particularly relates to a method for preparing waste polyethylene terephthalate polyol and its high-performance polyurethane modified asphalt. Background Technology

[0002] Traditional asphalt, as an indispensable core binder in road engineering, directly determines the durability and long-term performance of pavements through its comprehensive performance. However, in high-load, high-condition applications such as airport runways, bridge pavement layers, and porous asphalt pavements, traditional asphalt binders exhibit numerous inherent defects. Their rheological properties are extremely sensitive to temperature changes, easily leading to embrittlement and cracking at low temperatures, and exhibiting insufficient viscoelasticity and weak rutting resistance at high temperatures. Furthermore, their strength fails to meet requirements under continuous heavy loads. In addition, traditional asphalt is susceptible to multi-factor coupled aging due to environmental factors, resulting in continuous performance degradation and severely impacting pavement service life. These limitations collectively drive the development of high-performance asphalt binders for specific applications.

[0003] The emergence of polyurethane-modified asphalt technology offers an effective solution to the aforementioned problems. This technology utilizes the reaction of isocyanates and polyols to form a covalent cross-linked network, significantly optimizing the rheological and physical-mechanical properties of asphalt. However, existing polyurethane-modified asphalt technologies largely rely on petroleum-based polyols as reactants, leading to high material costs and exacerbating dependence on non-renewable petroleum resources, contradicting global sustainable development strategies and the concept of a circular economy. Therefore, developing innovative modification solutions that can further improve binder performance while reducing dependence on petroleum resources has become a key direction for the industry's development.

[0004] The depolymerization and recovery of polyethylene terephthalate (PET) to prepare polyol substitutes provides a sustainable development path for this field. For example, Chinese patents CN115427490A and CN120441432A both propose a PET glycolysis process using ethylene glycol as a depolymerizing agent and multiple catalysts working synergistically. Although this type of process improves the depolymerization efficiency of PET to some extent, it still has significant drawbacks, namely, the need for additional filtration afterward, which not only increases the complexity of the process but also poses a risk of secondary pollution, ultimately driving up recycling costs and hindering the large-scale application of the technology. In addition, the ethylene glycol depolymerization method can only produce a single type of PET polyol, making it difficult to adapt to the preparation of modified asphalt with different performance requirements, thus limiting its application diversity. Therefore, the industry urgently needs to develop a simplified PET glycolysis process that can minimize waste generated in subsequent processing, broaden the applicability of recyclable PET products, and provide highly adaptable polyol raw materials for the preparation of high-performance polyurethane modified asphalt. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a method for preparing waste polyethylene terephthalate (PET) polyols and their high-performance polyurethane-modified asphalt. The aim is to reduce dependence on petroleum-derived polyols by optimizing the glycolysis process, effectively shortening the preparation cycle and reducing production costs. Simultaneously, it provides diversified alternative materials for waste PET polyols in the road engineering field. While promoting the high-value utilization of recycled materials and contributing to sustainable development, the invention ensures that the prepared polyurethane-modified asphalt achieves the same performance levels as traditional high-performance polyurethane-modified asphalt at high, medium, and low temperatures.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A waste polyethylene terephthalate polyol is prepared from waste polyethylene terephthalate plastic bottles, a degradation agent and a catalyst in a mass ratio of 1:(0.5-3.5):(0.015-0.025).

[0008] This invention employs glycolysis to efficiently convert waste polyethylene terephthalate (PET) into waste PET polyols that can replace petroleum-based polyols. By systematically optimizing the glycolysis preparation process, it not only significantly shortens the PET degradation cycle and reduces dependence on petroleum-derived polyols, but also contributes to sustainable development through the recycling of waste PET materials. Using waste PET plastic bottles as raw materials, it achieves high-value utilization of waste, and the scientifically sound raw material ratio ensures stable polyol product performance and lays a solid foundation for the subsequent preparation of high-performance modified asphalt.

[0009] Furthermore, the molecular weight of the waste polyethylene terephthalate plastic bottle is 20,000-25,000 g / mol.

[0010] Furthermore, the degradation agent is one or more of polyethylene glycol 100, polyethylene glycol 200, polyethylene glycol 400 and polyethylene glycol 600.

[0011] The degradation agent selected in this invention can efficiently promote the depolymerization of waste PET; a variety of degradation agents are available, and the properties of polyols can be flexibly adjusted to meet the preparation requirements of different modified asphalts.

[0012] Furthermore, the catalyst is one or more of cobalt acetate, manganese acetate, and zinc acetate.

[0013] The cobalt acetate, manganese acetate, and zinc acetate catalysts selected in this invention have high catalytic efficiency and can improve the conversion rate of waste PET; the catalysts are environmentally friendly and easy to separate from the products, with no risk of secondary pollution, which meets the requirements of clean production.

[0014] This invention also provides a method for preparing waste polyethylene terephthalate polyol, comprising the following steps:

[0015] Waste polyethylene terephthalate plastic bottles are cut into fragments and dehydrated under vacuum conditions.

[0016] The waste polyethylene terephthalate plastic bottle fragments after dehydration are mixed with degradation agents and catalysts in stages by heating to obtain waste polyethylene terephthalate polyol.

[0017] The preparation process of this invention is simple, requiring no complex post-processing steps and shortening the production cycle; the combination of cutting and dehydration with segmented heating and mixing reduces energy consumption and production costs, while ensuring the purity of the polyol product.

[0018] Furthermore, the size of the fragment is 5mm × 5mm;

[0019] The dehydration process is as follows: dehydrate at 80-100℃ for 1-2 hours;

[0020] The specific operation steps of the segmented heating and mixing treatment are as follows: stir for 1 hour at a temperature of 185-195℃ and a stirring rate of 600-1000r / min, and then stir for 1-4 hours at a temperature of 230-250℃ and a stirring rate of 600-1000r / min.

[0021] This invention clarifies the fragment size, dehydration parameters, and segmented heating and stirring conditions, making the process more controllable; it improves the consistency of product performance and the conversion rate of waste PET, ensuring the stability of large-scale production.

[0022] The present invention also provides a high-performance polyurethane modified asphalt, comprising, by weight parts: 100 parts of 70# base asphalt and 40-60 parts of waste polyethylene terephthalate-based polyurethane.

[0023] The waste polyethylene terephthalate-based polyurethane is prepared from the waste polyethylene terephthalate polyol, polyether polyol, polyisocyanate and crosslinking agent as raw materials in a molar ratio of 0.5:0.3:0.2:1.

[0024] This invention utilizes waste PET polyol to further synthesize high-performance polyurethane-modified asphalt, significantly reducing material production costs and providing a more diversified and high-quality material solution for the road engineering field. During the preparation process, waste PET polyol, polyether polyol, crosslinking agent, and isocyanate form a synergistic reaction effect, laying a solid foundation for the superior performance of the modified asphalt. Furthermore, the scientifically sound formulation ratio of the modified asphalt, with the waste PET-based polyurethane and base asphalt working synergistically, significantly improves the overall performance of the asphalt, making it perfectly suited for high-performance applications such as high-grade roads and airport runways.

[0025] Furthermore, the polyether polyol is polytetramethylene ether diol (PTMG3000).

[0026] The polyisocyanate is diphenylmethane-4,4'-diisocyanate (MDI).

[0027] The crosslinking agent is castor oil (CO).

[0028] The polytetramethylene ether glycol, MDI, castor oil and waste PET polyols specified in this invention have good synergistic reaction; they can form a stable covalent crosslinking network, which enhances the mechanical properties and durability of modified asphalt.

[0029] This invention also provides a method for preparing high-performance polyurethane-modified asphalt, comprising the following steps:

[0030] After preheating the 70# base asphalt to a fully fluid state, add it to the mixing tank, maintain the system temperature at 120-130℃, add waste polyethylene terephthalate polyol, polyether polyol and crosslinking agent, and stir.

[0031] Then add polyisocyanate and continue stirring. The resulting sample is then subjected to development treatment to obtain high-performance polyurethane modified asphalt.

[0032] The preparation steps of this invention are easy to operate, and the step-by-step addition and stirring can ensure that the components are fully mixed; the development treatment step can make the reaction more thorough and improve the uniformity and stability of the modified asphalt performance.

[0033] Furthermore, the specific operation of the stirring is as follows: stirring at a stirring rate of 800-900 r / min for 15-20 minutes;

[0034] The specific operation for continuing stirring is as follows: stir for 20 minutes at a stirring rate of 800-900 r / min.

[0035] This invention specifies the stirring rate and time parameters to ensure uniform mixing and sufficient reaction of materials; avoids incomplete local reaction, and improves the consistency of modified asphalt product quality.

[0036] Furthermore, the specific operation of the development treatment is as follows: develop at 100-120℃ for 2-3 hours.

[0037] The development treatment conditions of this invention can promote the formation of a stable microstructure in the system; enhance the performance stability of modified asphalt and extend its service life in road engineering.

[0038] Compared with the prior art, the present invention has the following advantages and technical effects:

[0039] This invention achieves highly efficient conversion of waste PET through optimized glycolysis, with a conversion rate of up to 100%. The product requires no complex post-processing, and the process is simple, energy-efficient, and produces minimal pollution. The resulting high-performance polyurethane-modified asphalt exhibits excellent high and low temperature performance, elastic recovery, and fatigue resistance. Its softening point reaches a maximum of 125℃, its ductility at 5℃ reaches 65.7 cm, and its elastic recovery rate reaches up to 99.1%. Its fatigue life far exceeds that of traditional modified asphalt, making it particularly suitable for high-grade road engineering.

[0040] This invention not only reduces dependence on petroleum resources, is low-cost and environmentally friendly, but also provides a feasible technical approach for the high-value utilization of waste PET. Attached Figure Description

[0041] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0042] Figure 1 This is a process flow diagram for preparing waste PET polyols and further synthesizing high-performance polyurethane modified bitumen according to the present invention. Detailed Implementation

[0043] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0044] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0045] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0046] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0047] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0048] This invention provides a method for preparing waste polyethylene terephthalate (PET) polyols, specifically including the following steps:

[0049] 1. Raw material preparation: Weigh waste PET plastic bottles (molecular weight of 20,000-25,000 g / mol), a degradation agent, and a catalyst in a mass ratio of 1:(0.5-3.5):(0.015-0.025); wherein the degradation agent is one or more of polyethylene glycol 100, polyethylene glycol 200, polyethylene glycol 400, and polyethylene glycol 600, and the catalyst is one or more of cobalt acetate, manganese acetate, and zinc acetate. Exemplarily, in the following preferred embodiments of the present invention, the mass ratio of waste PET plastic bottles, degradation agent, and catalyst is 1:1.04:0.02, 1:2.08:0.02, or 1:3.15:0.02; the degradation agent is polyethylene glycol 100, polyethylene glycol 200, polyethylene glycol 400, or polyethylene glycol 600; and the catalyst is cobalt acetate, manganese acetate, or zinc acetate.

[0050] 2. Pretreatment: Cut waste PET plastic bottles into 5mm×5mm fragments, place them in a vacuum device, and dehydrate them at 80-100℃ for 1-2 hours. After completion, remove them for later use. For example, in the following preferred embodiment of the present invention, the vacuum dehydration temperature is selected as 90℃, and the dehydration time is selected as 2 hours.

[0051] 3. Segmented heating and mixing: Under normal pressure, add the dehydrated PET fragments, weighed degradation agent, and catalyst to a three-necked flat-bottomed flask equipped with a thermometer, condenser, and stirrer. First, stir for 1 hour at 185-195℃ (exemplary, 190℃) and 600-1000 r / min (exemplary, 600 r / min). Then, raise the temperature to 230-250℃ (exemplary, 240℃) and adjust the stirring speed to 600-1000 r / min (exemplary, 600 r / min, 800 r / min, or 1000 r / min), and continue stirring for 1-4 hours (exemplary, 1 hour, 2 hours, 3 hours, or 4 hours). After the reaction is complete, waste PET polyol is obtained. The product can be used directly in subsequent steps without additional post-treatment.

[0052] This invention also provides a waste polyethylene terephthalate-based polyurethane, which is prepared from waste polyethylene terephthalate polyol, polyether polyol, polyisocyanate, and crosslinking agent in a molar ratio of 0.5:0.3:0.2:1. The polyether polyol is polytetramethylene ether glycol (PTMG3000); the polyisocyanate is diphenylmethane-4,4'-diisocyanate (MDI); and the crosslinking agent is castor oil (CO).

[0053] This invention also provides a method for preparing high-performance polyurethane-modified asphalt (flowchart shown below). Figure 1 As shown), the specific steps include:

[0054] 1. Raw material preparation: Weigh 100 parts of 70# base asphalt and 40-60 parts of waste polyethylene terephthalate-based polyurethane (waste PET polyol, polyether polyol, polyisocyanate and crosslinking agent) according to the mass ratio. The molar ratio of waste PET polyol, polyether polyol, polyisocyanate and crosslinking agent is 0.5:0.3:0.2:1. The polyether polyol is polytetramethylene ether glycol (PTMG3000), the polyisocyanate is diphenylmethane-4,4'-diisocyanate (MDI), and the crosslinking agent is castor oil (CO).

[0055] 2. Base asphalt pretreatment: Place the 70# base asphalt in an oven at 140-150℃ (for example, the temperature is 150℃) to preheat it to a fully fluid state, and then transfer it to a mixing tank, maintaining the temperature inside the tank at 130℃.

[0056] 3. First stage of mixing: Add the weighed waste PET polyol, polyether polyol and crosslinking agent to the mixing tank, and stir for 20 minutes at a stirring rate of 800-900 r / min (for example, the stirring rate is 900 r / min) to ensure that the materials are mixed evenly.

[0057] 4. Second stage stirring: Keep the system temperature constant, add polyisocyanate to the mixing tank, adjust the stirring speed to 800-900 r / min (for example, the stirring speed is 900 r / min), and continue stirring for 20 minutes to allow the materials to react fully.

[0058] 5. Development treatment: Transfer the stirred mixture to an oven and develop it at 100℃ for 2 hours. After development, high-performance polyurethane modified asphalt based on waste PET polyol is obtained.

[0059] Unless otherwise specified, "room temperature" in this invention refers to 25±2℃; "atmospheric pressure" unless otherwise specified refers to 0.1MPa.

[0060] Unless otherwise specified, the term "parts" in this invention refers to parts by weight.

[0061] The raw materials used in the following embodiments of the present invention were sourced as follows: 70# base bitumen was purchased from Hebei Xinhai Chemical Group Co., Ltd.; waste PET plastic bottles were waste mineral water bottles with a molecular weight of 20,000-25,000 g / mol; polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, anhydrous manganese acetate, PTMG 3000, and castor oil were purchased from Beijing Mairuida Technology Co., Ltd.; diphenylmethane-4,4'-diisocyanate was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. All other materials were also purchased from the market.

[0062] The technical solution of the present invention will be further illustrated by the following embodiments.

[0063] In optimizing the glycolysis process, this invention calculates the PET conversion rate using the following formula:

[0064]

[0065] in C r W represents the PET conversion rate. PET,i W represents the initial mass of PET before glycolysis. PET,f This refers to the mass of undissolved PET after glycolysis.

[0066] Example 1

[0067] The preparation of a waste polyethylene terephthalate (PET) polyol comprises the following steps:

[0068] S1. Cut waste PET plastic bottles with a molecular weight of 20,000-25,000 g / mol into 5mm×5mm fragments, put them into a vacuum chamber, and dehydrate them at 90℃ for 2 hours.

[0069] S2. Under normal pressure, dehydrated PET fragments, polyethylene glycol 600 and cobalt acetate are added to a three-necked flat-bottomed flask equipped with a thermometer, condenser and stirrer in a mass ratio of 1:3.15:0.02. Stir for 1 hour at 190℃ and 600r / min.

[0070] S3. Then raise the temperature to 240℃, adjust the stirring speed to 600r / min, and continue stirring for 4 hours. After the reaction is completed, waste PET polyol is obtained.

[0071] Example 2

[0072] Same as Example 1, except that in step S3, the stirring time is adjusted to 3 hours.

[0073] Example 3

[0074] Same as Example 1, except that in step S3, the stirring time is adjusted to 2 hours.

[0075] Example 4

[0076] Same as Example 1, except that in step S3, the stirring time is adjusted to 1 hour, that is, the specific steps are as follows:

[0077] The preparation of a waste polyethylene terephthalate (PET) polyol comprises the following steps:

[0078] S1. Cut waste PET plastic bottles with a molecular weight of 20,000-25,000 g / mol into 5mm×5mm fragments, put them into a vacuum chamber, and dehydrate them at 90℃ for 2 hours.

[0079] S2. Under normal pressure, dehydrated PET fragments, polyethylene glycol 600 and cobalt acetate are added to a three-necked flat-bottomed flask equipped with a thermometer, condenser and stirrer in a mass ratio of 1:3.15:0.02. Stir for 1 hour at 190℃ and 600r / min.

[0080] S3. Then raise the temperature to 240℃, adjust the stirring speed to 600r / min, and continue stirring for 1 hour. After the reaction is completed, waste PET polyol is obtained.

[0081] Table 1 shows the conversion rate of waste PET at different stirring times in Examples 1-4.

[0082]

[0083] Example 5

[0084] Same as Example 4, except that in step S3, the stirring rate is adjusted to 800 r / min.

[0085] Example 6

[0086] Same as Example 4, except that in step S3, the stirring speed is adjusted to 1000 r / min. Specifically, the steps are as follows:

[0087] The preparation of a waste polyethylene terephthalate (PET) polyol comprises the following steps:

[0088] S1. Cut waste PET plastic bottles with a molecular weight of 20,000-25,000 g / mol into 5mm×5mm fragments, put them into a vacuum chamber, and dehydrate them at 90℃ for 2 hours.

[0089] S2. Under normal pressure, dehydrated PET fragments, polyethylene glycol 600 and cobalt acetate are added to a three-necked flat-bottomed flask equipped with a thermometer, condenser and stirrer in a mass ratio of 1:3.15:0.02. Stir for 1 hour at 190℃ and 600r / min.

[0090] S3. Then raise the temperature to 240℃, adjust the stirring speed to 1000r / min, and continue stirring for 1 hour. After the reaction is completed, waste PET polyol is obtained.

[0091] Table 2 shows the conversion rates of waste PET at different stirring rates in Examples 4-6.

[0092]

[0093] Example 7

[0094] Same as Example 6, except that in step S2, cobalt acetate is replaced by manganese acetate.

[0095] Example 8

[0096] Same as Example 6, except that in step S2, cobalt acetate is replaced by zinc acetate. Specifically, the steps are as follows:

[0097] The preparation of a waste polyethylene terephthalate (PET) polyol comprises the following steps:

[0098] S1. Cut waste PET plastic bottles with a molecular weight of 20,000-25,000 g / mol into 5mm×5mm fragments, put them into a vacuum chamber, and dehydrate them at 90℃ for 2 hours.

[0099] S2. Under normal pressure, add the dehydrated PET fragments, polyethylene glycol 600 and zinc acetate in a mass ratio of 1:3.15:0.02 into a three-necked flat-bottomed flask equipped with a thermometer, condenser and stirrer, and stir for 1 hour at 190℃ and 600r / min.

[0100] S3. Then raise the temperature to 240℃, adjust the stirring speed to 1000r / min, and continue stirring for 1 hour. After the reaction is completed, waste PET polyol (denoted as PETG6) is obtained.

[0101] Table 3 shows the conversion rates of waste PET under different catalysts in Examples 6-8.

[0102]

[0103] Example 9

[0104] Same as Example 8, except that in step S2, polyethylene glycol 600 is replaced with polyethylene glycol 400, and the mass ratio of PET fragments, polyethylene glycol 400 and zinc acetate is 1:2.08:0.02. The resulting waste PET polyol is denoted as PETG4.

[0105] Example 10

[0106] Same as Example 8, except that in step S2, polyethylene glycol 600 is replaced with polyethylene glycol 200, and the mass ratio of PET fragments, polyethylene glycol 200 and zinc acetate is 1:1.04:0.02. The resulting waste PET polyol is denoted as PETG2.

[0107] Example 11

[0108] Same as Example 8, except that in step S2, polyethylene glycol 600 is replaced with polyethylene glycol 100, and the mass ratio of PET fragments, polyethylene glycol 100 and zinc acetate is 1:0.52:0.02. The resulting waste PET polyol is denoted as PETG1.

[0109] Table 4 shows the conversion rates of waste PET under different types and amounts of degrading agents in Examples 8-11.

[0110]

[0111] Note: The dosage in the table represents the molar ratio of waste PET to the degradation agent (polyethylene glycol 100, polyethylene glycol 200, polyethylene glycol 400 or polyethylene glycol 600).

[0112] To characterize the hydroxyl value and molecular weight of the waste PET polyols prepared in Examples 8-11, the present invention uses the imidazole-catalyzed pyrotetraic dianhydride method in ASTM D4274-21 to determine their hydroxyl value, and uses gel permeation chromatography (GPC) to characterize their number-average molecular weight. The results are shown in Table 5.

[0113] Table 5. Hydroxyl values ​​and molecular weights of the waste PET polyols prepared in Examples 8-11

[0114]

[0115] Application Example 1

[0116] The preparation steps of a high-performance polyurethane-modified asphalt are as follows:

[0117] (1) Place 100g of 70# base asphalt in an oven at 150℃ and preheat it to a fully fluid state. Then transfer it to a mixing tank and maintain the temperature inside the tank at 130℃. Add the waste PET polyol, PTMG3000 and castor oil (CO) prepared in Example 8 to the mixing tank according to the mass composition in Table 6. Stir at a stirring rate of 900r / min for 20 minutes.

[0118] (2) Keep the system temperature constant, add diphenylmethane-4,4'-diisocyanate (MDI) to the stirred tank, adjust the stirring speed to 900 r / min, and continue stirring for 20 minutes;

[0119] (3) Transfer the stirred mixture to an oven and develop it in an oven at 100°C for 2 hours. After development, waste PET polyol-based high-performance polyurethane modified asphalt is obtained.

[0120] The molar ratio of waste PET polyol, PTMG3000, CO and MDI is 0.5:0.3:0.2:1.

[0121] Application Example 2

[0122] Similar to Application Example 1, except that the waste PET polyol prepared in Example 8 is replaced by the waste PET polyol prepared in Example 9, and the specific amount is shown in Table 6.

[0123] Application Example 3

[0124] Similar to Application Example 1, except that the waste PET polyol prepared in Example 8 is replaced by the waste PET polyol prepared in Example 10, and the specific amount is shown in Table 6.

[0125] Application Example 4

[0126] Similar to Application Example 1, except that the waste PET polyol prepared in Example 8 is replaced by the waste PET polyol prepared in Example 11 in equal mass. The specific amount is shown in Table 6.

[0127] Comparative Application Example 1

[0128] Similar to Application Example 1, the difference is that the waste PET polyol is removed. The specific dosage is shown in Table 6.

[0129] Table 6 shows the mass composition used in Application Examples 1-4 and Comparative Application Example 1.

[0130]

[0131] Performance testing:

[0132] According to the specifications in JTG E20 T0604, T0606-2011 and AASHTO MP19-10 of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering", the two major indicators of application examples 1-4 and comparative application example 1, namely elastic recovery rate, were tested. R ), irreversible creep flexibility ( J nr ), shear viscosity and fatigue life ( N f Elastic recovery rate () R ) and irreversible creep compliance ( J nr The two parameters were obtained through multi-stress creep recovery (MSCR) testing at 64°C, and the viscosity was obtained through zero-shear viscosity (ZSV) testing at 60°C. Fatigue life ( N f The results were obtained through a linear amplitude scanning test conducted at 20℃, and the test results are shown in Table 7.

[0133] Table 7 shows the test results of the physical and rheological properties of Application Examples 1-4 and Comparative Application Example 1.

[0134]

[0135] As shown in Table 7, this invention successfully prepared a high-performance polyurethane-modified asphalt. Its core innovation lies in achieving efficient and high-value conversion of waste PET through an optimized glycolysis process, and synthesizing a polyurethane-modified asphalt with excellent comprehensive performance based on this. Regarding process optimization, this invention systematically improved key parameters such as the type of degrading agent (e.g., PEG100, PEG200, PEG400, and PEG600), catalyst, and stirring rate, significantly shortening the PET degradation time to several hours and achieving a near 100% conversion rate. This process is simple and efficient, requires no complex post-treatment of the product, has low energy consumption and low pollution, and provides a practical and feasible technical approach for the large-scale, low-cost recycling of waste PET. Based on this highly efficient glycolysis product, namely waste PET polyols with different hydroxyl values ​​(131.1-368.7 mg KOH / g) and molecular weights (631-1334 g / mol), this invention further prepared high-performance polyurethane-modified asphalt by precisely reacting it with waste PET polyols, polyether polyols, crosslinking agents (CO), and diphenylmethane-4,4'-diisocyanate (MDI). Performance test results show that this material exhibits excellent comprehensive performance in terms of high-temperature stability, low-temperature crack resistance, and fatigue performance. Specifically, its elastic recovery rate (… R The fatigue life can reach up to 99.1%, and the fatigue life (N f It achieves up to 839,461 cycles, significantly outperforming traditional modified asphalt; its softening point can be increased to 125℃, and its irreversible creep compliance (…) J nr As low as 0.02 kPa -1 This invention demonstrates excellent resistance to rutting and deformation; simultaneously, its ductility reaches 65.7 cm at 5℃, exhibiting excellent low-temperature flexibility and crack resistance. In summary, this invention innovatively realizes the transformation of waste PET into high-value-added road engineering materials, effectively reducing dependence on petroleum-based resources and production costs, and providing a green, economical, and sustainable high-value utilization solution for addressing "white pollution." The prepared modified asphalt exhibits outstanding performance, environmental friendliness, and economic efficiency, possessing significant engineering application potential and a broad market prospect, fully aligning with the development direction of a green circular economy.

[0136] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A waste polyethylene terephthalate polyol, characterized in that, It is prepared from waste polyethylene terephthalate plastic bottles, degradation agents and catalysts as raw materials in a mass ratio of 1:(0.5-3.5):(0.015-0.025); The degradation agent is one or more of polyethylene glycol 100, polyethylene glycol 200, polyethylene glycol 400 and polyethylene glycol 600; The catalyst is one or more of cobalt acetate, manganese acetate, and zinc acetate; The preparation method of the waste polyethylene terephthalate polyol includes the following steps: cutting the waste polyethylene terephthalate plastic bottle into fragments and dehydrating it under vacuum conditions; mixing the dehydrated waste polyethylene terephthalate plastic bottle fragments with a degradation agent and a catalyst in a segmented heating process to obtain the waste polyethylene terephthalate polyol. The size of the fragment is 5mm × 5mm; The dehydration process is as follows: dehydrate at 80-100℃ for 1-2 hours; The specific operation steps of the segmented heating and mixing treatment are as follows: stir for 1 hour at a temperature of 185-195℃ and a stirring rate of 600-1000r / min, and then stir for 1-4 hours at a temperature of 230-250℃ and a stirring rate of 600-1000r / min.

2. A high-performance polyurethane-modified asphalt, characterized in that, By weight, it includes: 100 parts of 70# base bitumen and 40-60 parts of waste polyethylene terephthalate-based polyurethane; The waste polyethylene terephthalate-based polyurethane is prepared from the waste polyethylene terephthalate polyol, polyether polyol, polyisocyanate and crosslinking agent described in claim 1 as raw materials in a molar ratio of 0.5:0.3:0.2:

1.

3. The high-performance polyurethane-modified asphalt according to claim 2, characterized in that, The polyether polyol is polytetramethylene ether glycol; and / or... The polyisocyanate is diphenylmethane-4,4'-diisocyanate; and / or, The crosslinking agent is castor oil.

4. A method for preparing high-performance polyurethane-modified asphalt as described in any one of claims 2-3, characterized in that, Includes the following steps: After preheating the 70# base asphalt to a fully fluid state, add it to the mixing tank, maintain the system temperature at 120-130℃, add waste polyethylene terephthalate polyol, polyether polyol and crosslinking agent, and stir. Then add polyisocyanate and continue stirring. The resulting sample is then subjected to development treatment to obtain high-performance polyurethane modified asphalt.

5. The method for preparing high-performance polyurethane-modified asphalt according to claim 4, characterized in that, The specific operation of the stirring is as follows: stirring at a stirring rate of 800-900 r / min for 15-20 minutes; and / or, The specific operation for continuing stirring is as follows: stir for 20 minutes at a stirring rate of 800-900 r / min.

6. The method for preparing high-performance polyurethane-modified asphalt according to claim 4, characterized in that, The specific procedure for the development treatment is as follows: develop at 100-120℃ for 2-3 hours.

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