Waste polyurethane modified asphalt as well as preparation method and application thereof

Abstract

The invention relates to the technical field of modified asphalt, in particular to waste polyurethane modified asphalt as well as a preparation method and application of the waste polyurethane modified asphalt. The modified asphalt is prepared from the following components in parts by weight: 80 to 120 parts of petroleum asphalt, 5 to 20 parts of waste polyurethane, 5 to 15 parts of calcium nitrate, 5 to 35 parts of a modifier, 5 to 15 parts of a cross-linking agent, 1 to 5 parts of a compatilizer, 1 to 5 parts of a surfactant and 15 to 60 parts of water. Waste polyurethane and petroleum asphalt are used as main raw materials, calcium nitrate, a modifier, a cross-linking agent, a compatilizer and a surfactant are used as co-participating assistants, and the addition ratio of the raw materials is adjusted in a targeted manner, so that the prepared waste polyurethane modified asphalt has good compatibility and shows relatively excellent high-temperature stability and anti-rutting performance.

Description

Technical Field

[0001] The present invention relates to the technical field of modified asphalt, and particularly relates to a waste polyurethane asphalt and its preparation method and application. Background Art

[0002] With the rapid development of industrialization, the generation amount of waste polyurethane materials is increasing day by day. As a kind of polymer material that is difficult to degrade, improper treatment of waste polyurethane will cause serious pollution to the environment. The treatment of waste polyurethane has become an important topic of the times, and it has far-reaching significance for the development of green industry and the promotion of the national solid waste utilization strategy.

[0003] However, the existing waste polyurethane recovery methods mainly include four methods: energy recovery, physical recovery, chemical recovery, and biological recovery, focusing on the degradation of waste polyurethane. It can reduce the pollution of waste polyurethane as solid waste to the environment, but its pollution reduction effect is limited, and a large amount of harmful emissions will still be generated, and it has little effect on resource recycling and reuse.

[0004] As a widely used road construction material, asphalt plays an important role in road paving and maintenance. However, traditional asphalt materials have problems such as insufficient durability and poor anti-aging performance, which limit their application in high-performance road engineering. In order to improve the performance of asphalt, adding polyurethane to asphalt to make polyurethane-modified asphalt is an effective solution, which can greatly improve the high-temperature performance of asphalt. The existing polyurethane-modified asphalt uses special polyurethane powder as a modifier, and the cost of the obtained product is relatively high, which restricts its practical application in engineering. Summary of the Invention

[0005] The purpose of the present invention is to provide a waste polyurethane-modified asphalt and its preparation method and application in view of the problem that the existing technology lacks an efficient method for combining waste polyurethane and asphalt. The waste polyurethane-modified asphalt provided by this application uses waste polyurethane and petroleum asphalt as the main raw materials, and uses calcium nitrate, modifier, cross-linking agent, compatibilizer, and surfactant as co-participating auxiliaries, and specifically adjusts the addition ratio of each raw material, so that the prepared waste polyurethane-modified asphalt has good compatibility and exhibits excellent high-temperature stability and rutting resistance.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows: A waste polyurethane-modified asphalt is prepared from the following raw materials by weight: 80 parts to 120 parts of petroleum asphalt, 5 parts to 20 parts of waste polyurethane, 5 parts to 15 parts of calcium nitrate, 5 parts to 35 parts of modifier, 5 parts to 15 parts of cross-linking agent, 1 part to 5 parts of compatibilizer, 1 part to 5 parts of surfactant, and 15 parts to 60 parts of water.

[0007] The waste polyurethane modified asphalt provided by the present invention is prepared from the following raw materials by weight: 80 parts to 120 parts of petroleum asphalt, 5 parts to 20 parts of waste polyurethane, 5 parts to 15 parts of calcium nitrate, 5 parts to 35 parts of modifier, 5 parts to 15 parts of crosslinking agent, 1 part to 5 parts of compatibilizer, 1 part to 5 parts of surfactant, and 15 parts to 60 parts of water. Using waste polyurethane and petroleum asphalt as the main raw materials, and using calcium nitrate, modifier, crosslinking agent, compatibilizer and surfactant as co-participating auxiliaries, and specifically adjusting the addition ratio of each raw material, the prepared waste polyurethane modified asphalt has good compatibility and exhibits excellent high-temperature stability and rutting resistance.

[0008] Further, it is prepared from the following raw materials by weight: 100 parts to 120 parts of petroleum asphalt, 10 parts to 20 parts of waste polyurethane, 10 parts to 15 parts of calcium nitrate, 20 parts to 30 parts of modifier, 10 parts to 15 parts of crosslinking agent, 2 parts to 5 parts of compatibilizer, 1 part to 3 parts of surfactant, and 40 parts to 50 parts of water.

[0009] Further, the modifier includes at least one of epoxy resin, polyol and amine compound; the crosslinking agent includes at least one of divinylbenzene, isocyanate and aziridine; the compatibilizer includes at least one of naphthenic oil, aromatic oil and vegetable oil; the surfactant includes at least one of quaternary ammonium salt emulsifier, alkylamide polyamine emulsifier, aminated lignin emulsifier and sulfate ester salt emulsifier.

[0010] Further, it also includes 0.1 part to 2 parts of stabilizer; the stabilizer includes at least one of magnesium oxide, calcium chloride, zinc chloride, carbon black, calcium phosphate and barium sulfate.

[0011] Another object of the present invention is to provide a preparation method of the above waste polyurethane modified asphalt.

[0012] A preparation method of the above waste polyurethane modified asphalt includes the following steps: Mix waste polyurethane with the modifier and perform ball milling treatment to obtain the first material; Add the stabilizer and surfactant to water and perform colloid grinding treatment to obtain the second material; Heat-treat the petroleum asphalt, add calcium nitrate, mix, continue heating to melting, add the first material, and perform primary shear stirring to obtain the third material; Perform a second shear treatment on the third material, and synchronously add the crosslinking agent and the second material. If there is a compatibilizer, add it together. After the shearing is completed, cool to room temperature to obtain the waste polyurethane modified asphalt.

[0013] Further, the temperature of the heat treatment of the petroleum asphalt is 140°C to 180°C.

[0014] Further, the rotational speed of the first shearing is 1500 r / min to 3000 r / min, and the time of the first shearing is 30 min to 90 min.

[0015] Further, the rotational speed of the second shearing is 4000 r / min to 6000 r / min, and the time of the second shearing is 30 min to 90 min.

[0016] Another object of the present invention is to provide the application of the waste polyurethane modified asphalt or the waste polyurethane modified asphalt prepared by the above preparation method.

[0017] Such as the application of the waste polyurethane modified asphalt or the waste polyurethane modified asphalt prepared by the above preparation method in the preparation of asphalt mixture.

[0018] Further, the asphalt mixture is prepared from the following raw materials by weight: 2 to 10 parts of waste polyurethane modified asphalt, 60 to 100 parts of aggregate, 5 to 10 parts of mineral powder, and 1 to 10 parts of auxiliary agent.

[0019] To sum up, due to the adoption of the above technical solutions, the beneficial effects of the present invention are: 1. The waste polyurethane modified asphalt provided by the present invention is prepared from the following raw materials by weight: 80 to 120 parts of petroleum asphalt, 5 to 20 parts of waste polyurethane, 5 to 15 parts of calcium nitrate, 5 to 35 parts of modifier, 5 to 15 parts of crosslinking agent, 1 to 5 parts of compatibilizer, 1 to 5 parts of surfactant, and 15 to 60 parts of water. Using waste polyurethane and petroleum asphalt as the main raw materials, and using calcium nitrate, modifier, crosslinking agent, compatibilizer and surfactant as co-participating auxiliary agents, and specifically adjusting the addition ratio of each raw material, the prepared waste polyurethane modified asphalt has good compatibility and exhibits excellent high-temperature stability and rutting resistance.

[0020] 2. The present invention provides a preparation method of waste polyurethane modified asphalt, which is simple in operation and easy to control.

[0021] 3. The present invention provides an asphalt mixture containing waste polyurethane modified asphalt, which uses waste polyurethane modified asphalt, aggregate, mineral powder and auxiliary agent as raw materials and is used for road construction, showing good asphalt performance. Specific Embodiments

[0022] In order to make the objects, technical solutions and advantages of the present invention clearer, the following examples are used to further describe the present invention in detail. It should be understood that the specific examples described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] Existing waste polyurethane (waste polyurethane mainly comes from the scraps and mold overflows in the production of polyurethane products, such as automotive interiors, shoe soles, packaging materials, etc., waste materials such as seat foams, sound insulation materials, and dashboard fillers in the automotive manufacturing industry, circuit board encapsulation materials and equipment cushions in the electronic and electrical industries. It is likely to contain physical impurities such as metal fragments, other plastics, fibers, rubber, and wood, and may also contain various chemical impurities such as additives, unreacted monomers, catalysts, adhesives, and coatings. It may also adsorb pollutants such as oil stains and dust.) recycling methods mainly include four methods: energy recovery, physical recovery, chemical recovery, and biological recovery, focusing on the degradation of waste polyurethane. It can reduce the environmental pollution caused by waste polyurethane as solid waste, but its pollution reduction effect is limited, and a large amount of harmful emissions will still be generated, and its role in resource recycling and reuse is very small.

[0024] As a widely used road construction material, asphalt plays an important role in road paving and maintenance. However, traditional asphalt materials have problems such as insufficient durability and poor anti-aging performance, which limit their application in high-performance road engineering. To improve the performance of asphalt, adding polyurethane to asphalt to make polyurethane-modified asphalt is an effective solution, which can significantly improve the high-temperature performance of asphalt. Existing polyurethane-modified asphalt uses special polyurethane powder as a modifier, and the resulting product has a high cost, restricting its practical application in engineering.

[0025] The existing technology lacks a method for efficiently combining waste polyurethane and asphalt. For example, as shown in Comparative Example 9, directly physically mixing waste polyurethane and petroleum asphalt results in poor compatibility between the two, and they cannot exhibit good high-temperature stability and rutting resistance.

[0026] Therefore, the present invention provides a waste polyurethane-modified asphalt, which is prepared from the following raw materials by weight: 80 parts to 120 parts of petroleum asphalt, 5 parts to 20 parts of waste polyurethane, 5 parts to 15 parts of calcium nitrate, 5 parts to 35 parts of modifier, 5 parts to 15 parts of crosslinking agent, 1 part to 5 parts of compatibilizer, 1 part to 5 parts of surfactant, and 15 parts to 60 parts of water.

[0027] The present invention uses waste polyurethane and petroleum asphalt as the main raw materials, and uses calcium nitrate, modifier, crosslinking agent, compatibilizer, and surfactant as co-participating auxiliaries, and specifically adjusts the addition ratio of each raw material, so that the prepared waste polyurethane-modified asphalt has good compatibility and exhibits excellent high-temperature stability and rutting resistance.

[0028] Preferably, it is prepared from the following raw materials by weight: 100 to 120 parts of petroleum asphalt, 10 to 20 parts of waste polyurethane, 10 to 15 parts of calcium nitrate, 20 to 30 parts of modifier, 10 to 15 parts of crosslinking agent, 2 to 5 parts of compatibilizer, 1 to 3 parts of surfactant, and 40 to 50 parts of water. Reasonable control of the addition ratio of each raw material can make the waste polyurethane and petroleum asphalt better compatible, and show better high-temperature stability and rutting resistance.

[0029] Specifically, calcium nitrate, as a reaction catalyst, can form strong intermolecular forces with polar groups in polyurethane and asphalt, improving the compatibility between asphalt and polyurethane.

[0030] In some embodiments, the petroleum asphalt is any one of 50#, 70#, and 90#.

[0031] In some embodiments, the modifier includes at least one of epoxy resin, polyol, and amine compound. The modifier reacts with the isocyanate groups in polyurethane, and a crosslinked network structure is formed inside the system. There are many soft segment structures, the ratio of soft segments to hard segments decreases, and the flexibility of the molecular chain becomes better, which can effectively improve the compatibility between waste polyurethane and petroleum asphalt. Specifically, epoxy resin is a high molecular compound, a multifunctional polymer composed of epoxy groups and other resins, usually a colorless or light yellow viscous liquid or solid. For example, the polyol is selected from at least one of ethylene glycol, propylene glycol, glycerol, and pentaerythritol. For example, the amine compound is selected from at least one of ethylenediamine, hexamethylenediamine, and diethylenetriamine.

[0032] In some embodiments, the crosslinking agent includes at least one of divinylbenzene, isocyanate, and aziridine. The crosslinking agent can promote the chemical crosslinking reaction between asphalt and modifier, forming a more stable colloidal system. This stability makes the modified asphalt not easily segregate or degrade during long-term storage and transportation, and gives it better anti-deformation ability and rutting resistance at high temperatures. For example, the isocyanate is selected from at least one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), and diphenylmethane diisocyanate (MDI).

[0033] In some embodiments, the compatibilizer includes at least one of naphthenic oil, aromatic oil, and vegetable oil. The compatibilizer can effectively improve the compatibility between asphalt and modifier, promoting more uniform mixing and dispersion of the two. This not only helps to enhance the overall homogeneity and structural stability of the modified asphalt, but also effectively prevents the occurrence of delamination or segregation. In addition, the use of the compatibilizer can also reduce the viscosity of the modified asphalt, thereby improving its processing performance and flow characteristics, making the asphalt easier to operate and control during construction.

[0034] In some embodiments, the surfactant includes at least one of quaternary ammonium salt emulsifiers, alkyl amide polyamine emulsifiers, aminated lignin emulsifiers, and sulfate ester salt emulsifiers.

[0035] In some embodiments, it further includes 0.1 part to 2 parts of a stabilizer; the stabilizer includes at least one of magnesium oxide, calcium chloride, zinc chloride, carbon black, calcium phosphate, and barium sulfate. By adding the stabilizer, the high performance of the modified asphalt can be better achieved.

[0036] Meanwhile, the present invention also provides a method for preparing the waste polyurethane modified asphalt as described above, comprising the following steps: Mix waste polyurethane with a modifier and perform ball milling treatment to obtain a first material; Add the stabilizer and the surfactant to water and perform colloid grinding treatment to obtain a second material; Heat the petroleum asphalt, add calcium nitrate, mix, continue heating until molten, add the first material, and perform primary shear stirring to obtain a third material; Perform a second shear treatment on the third material, and synchronously add a crosslinking agent and the second material. If there is a compatibilizer, add it together. After the shearing is completed, cool to room temperature to obtain the waste polyurethane modified asphalt.

[0037] The preparation method provided by the present invention is simple in operation and easy to control.

[0038] In some embodiments, the temperature for heating the petroleum asphalt is 140°C to 180°C.

[0039] In some embodiments, the rotation speed of the primary shear is 1500 r / min to 3000 r / min, and the time of the primary shear is 30 min to 90 min. Ensure that the road petroleum asphalt in the hot melt state can be in full contact with the waste polyurethane powder, and achieve uniform mixing of the two through constant-speed stirring.

[0040] In some embodiments, the rotation speed of the second shear is 4000 r / min to 6000 r / min, and the time of the second shear is 30 min to 90 min. Make the emulsion evenly mixed under the shearing action of the crosslinking agent and the compatibilizer Use of the above waste polyurethane modified asphalt or waste polyurethane modified asphalt prepared by the above preparation method in the preparation of asphalt mixtures.

[0041] In some embodiments, the asphalt mixture is prepared from the following raw materials by weight: 2 parts to 10 parts of waste polyurethane modified asphalt, 60 parts to 100 parts of aggregate, 5 parts to 10 parts of mineral powder, and 1 part to 10 parts of additive.

[0042] In some embodiments, the asphalt mixture is prepared by the following method: The weighed aggregate is placed in an environment of 140-160°C for drying for 30-60 minutes, and then an additive is added and fully stirred, and a constant temperature state is maintained to obtain a primary mixed material; The waste polyurethane modified asphalt is heated to 160-180° C., and then the primary mixture in a constant temperature state is added, and after being fully stirred and mixed, the modified asphalt mixture is obtained.

[0043] In some embodiments, basalt is selected as coarse aggregate and limestone is selected as fine aggregate; the mineral powder material is limestone powder with a particle size less than 0.075 mm; at the same time, nano-zinc oxide is added as a functional additive.

[0044] In some embodiments, a discontinuous grading process is used to reasonably mix the coarse aggregate, fine aggregate and functional additives to prepare a primary mixture.

[0045] For further explanation, the following examples and comparative examples are provided.

[0046] In the following examples and comparative examples, the treatment process of waste polyurethane is as follows: Step 1, physical sorting First, the waste polyurethane raw materials are roughly crushed.

[0047] A double-axis shear crusher is used to cut the waste PU into 3-5 cm fragments; metal impurities are removed by a permanent magnetic drum (magnetic field strength ≥ 3000 Gauss). Finally, a 10mm aperture sieve is used for vibration screening to separate large foreign objects such as wood and rubber. The sieved materials are manually re-inspected and removed to obtain waste polyurethane fragments.

[0048] Step 2, Chemical Cleaning The waste polyurethane scraps treated as above were put into a soaking tank with an organic solvent at a mass ratio of 1:5; the stirring speed was adjusted to 50 rpm, the temperature was adjusted to 40±5°C, and the soaking time was 30 minutes to dissolve the surface oil, phthalate plasticizers and some adhesives; then centrifugal dehydration was performed (speed 1500 rpm, time 10 minutes), and finally dried with 80°C circulating hot air for 1.5 hours.

[0049] It should be noted that the organic solvent is one of the bio-based solvents D-limonene or 70% ethanol aqueous solution.

[0050] Step 3: Neutralization First, evenly spray 5% sodium bicarbonate solution onto the surface of waste polyurethane scraps at a spraying amount of 10L / ton PU; then pile it for 1 hour to neutralize the residual acid catalyst; finally rinse with clean water until neutral, and dry it with hot air at 60°C for 30 minutes to obtain the required waste polyurethane material.

[0051] Example 1 This embodiment provides a waste polyurethane modified asphalt, which comprises the following components by weight: 80 parts of 70# petroleum asphalt, 5 parts of waste polyurethane, 15 parts of calcium nitrate, 20 parts of modifier epoxy resin, 2 parts of compatibilizer cyclohexane oil, 10 parts of cross-linking agent divinylbenzene, 0.5 parts of stabilizer magnesium oxide, 1 part of surfactant which is a quaternary ammonium salt emulsifier and 30 parts of water.

[0052] The preparation method of the waste polyurethane modified asphalt in this embodiment is as follows: Step 1: accurately weigh the raw materials of each component according to the above-set ratio and store them properly for subsequent use; Step 2, mixing the pre-weighed waste polyurethane with the modifier, and processing the mixture through a ball milling process to finally obtain a modified waste polyurethane powder material; The present invention does not limit the specific implementation of the ball milling process, and it is only necessary to ensure that the modifier is in full contact with the waste polyurethane to achieve the optimal modification effect. In this embodiment, the waste polyurethane and epoxy resin are mixed and stirred at a speed of 50 rpm for 24 hours, then washed with anhydrous ethanol, and the ball milled product is placed in a 65°C environment and dried for 8 hours to remove the residual solvent, and finally passed through an 80-mesh screen to obtain modified waste polyurethane powder.

[0053] Step 3, putting the stabilizer and the surfactant into warm water at 50-60°C, and treating them by a colloid grinding process to obtain a uniform emulsion; The present invention does not limit the specific implementation of the rubber grinding process, but only needs to ensure that the stabilizer and the surfactant are fully dispersed in the water to form a uniform and stable emulsified system, so as to promote the effective fusion of road petroleum asphalt and waste polyurethane powder in the subsequent process. First, the distance between the stator and the rotor of the colloid mill was set to 100 μm; then the distance between the stator and the rotor of the colloid mill was set to 45 μm, and the grinding was performed for 7 minutes to complete the colloid grinding process.

[0054] Step 4: First, heat the road petroleum asphalt to 155°C, then add the pre-prepared calcium nitrate powder and stir it thoroughly to make it reach a uniform hot melt state. Then, add the recycled polyurethane particles in a high-speed shearing device, achieve uniform dispersion through mechanical shearing, and obtain the primary product of polyurethane modified asphalt; The present invention does not limit the specific implementation method for the road petroleum asphalt and calcium nitrate to reach the hot-melt state. The key lies in ensuring that the road petroleum asphalt is in the hot-melt state. In this embodiment, a method of heating the road petroleum asphalt and calcium nitrate together to 160 °C is adopted to achieve its hot-melt state.

[0055] The present invention does not specifically limit the implementation manner of the primary shearing treatment. The key lies in ensuring that the road petroleum asphalt in the hot-melt state can fully contact with the waste polyurethane powder, and realizing the uniform mixing of the two through constant-speed stirring.

[0056] In this embodiment, the hot-melt road petroleum asphalt is subjected to shearing treatment at a speed of 1500 revolutions per minute for 30 minutes. During this process, the waste polyurethane powder is gradually added. After both are completely added, the shearing treatment is continued for 60 minutes until the shearing is fully completed, and finally the primary product of the waste polyurethane modified asphalt is obtained.

[0057] Step 5, the crude product of the waste polyurethane modified asphalt is subjected to a second shearing treatment, and a crosslinking agent, a compatibilizer and an emulsion are added simultaneously. After shearing evenly, it is cooled to obtain the waste polyurethane modified asphalt.

[0058] The present invention does not limit the specific manner of the second shearing treatment, as long as it can make the emulsion, the crosslinking agent and the compatibilizer be mixed evenly under the shearing action. In this embodiment, the crosslinking agent, the compatibilizer and the emulsion are slowly added. After the crosslinking agent, the compatibilizer and the emulsion are added, the shearing treatment is continued at a rate of 4000 r / min for 60 min to obtain the waste polyurethane modified asphalt.

[0059] Example 2 100 parts of 70# petroleum asphalt, 10 parts of waste polyurethane, 10 parts of calcium nitrate, 20 parts of modifier epoxy resin, 2 parts of compatibilizer naphthenic oil, 10 parts of crosslinking agent divinylbenzene, 1 part of stabilizer magnesium oxide, 1 part of surfactant quaternary ammonium salt emulsifier and 40 parts of water.

[0060] And the preparation method of the waste polyurethane modified asphalt in this embodiment is as follows: Step 1, accurately weigh each component raw material according to the above-set ratio and store it properly for subsequent use; Step 2, after mixing the pre-weighed waste polyurethane with the modifier, perform treatment through a ball milling process. Mix and stir the waste polyurethane and epoxy resin at a speed of 100 revolutions per minute for 12 hours, then wash with absolute ethanol, place the ball milled product in an environment of 70 °C and dry for 6 hours to remove the residual solvent, and finally pass through an 80-mesh sieve to obtain the modified waste polyurethane powder.

[0061] Step 3: Put the stabilizer and surfactant into warm water at 55°C and process them through colloid grinding technology. Specifically, set the distance between the stator and rotor of the colloid mill to 90 μm; then set the distance between the stator and rotor of the colloid mill to 50 μm and grind for 8 minutes to obtain a uniform emulsion. Step 4: First, heat the road petroleum asphalt to 145°C, then add the pre-prepared calcium nitrate powder and stir well to make it reach a uniform hot-melt state. Next, synchronously add the recycled polyurethane particles into the high-speed shearing equipment and achieve uniform dispersion through mechanical primary shearing. Specifically, perform shearing treatment on the hot-melt road petroleum asphalt at a speed of 1500 revolutions per minute for 20 minutes. During this process, gradually add the waste polyurethane powder. After both are completely added, continue the shearing treatment for 40 minutes until the shearing is fully completed, and finally obtain the primary product of waste polyurethane modified asphalt.

[0062] Step 5: Perform a second shearing treatment on the crude waste polyurethane modified asphalt, slowly add the cross-linking agent, compatibilizer, and emulsion. After the cross-linking agent, compatibilizer, and emulsion are added, continue the shearing treatment at a rate of 4000 r / min for 40 minutes to obtain the waste polyurethane modified asphalt.

[0063] Example 3 This example provides a waste polyurethane modified asphalt, which contains the following components by weight: 120 parts of 70# petroleum asphalt, 20 parts of waste polyurethane, 15 parts of calcium nitrate, 30 parts of modifier epoxy resin, 2 parts of compatibilizer naphthenic oil, 15 parts of cross-linking agent divinylbenzene, 2 parts of stabilizer magnesium oxide, 3 parts of surfactant quaternary ammonium salt emulsifier, and 50 parts of water.

[0064] And the preparation method of the waste polyurethane modified asphalt in this example is as follows: Step 1: Accurately weigh each component raw material according to the above-set ratio and store it properly for subsequent use; Step 2: After mixing the pre-weighed waste polyurethane with the modifier, process it through ball milling technology. Specifically, mix and stir the waste polyurethane and epoxy resin at a speed of 150 revolutions per minute for 6 hours, then wash it with absolute ethanol, place the ball-milled product in an 85°C environment and dry it for 2 hours to remove the residual solvent, and finally pass through an 80-mesh sieve to obtain the modified waste polyurethane powder.

[0065] Step 3: Put the stabilizer and surfactant into warm water at 60°C and process them through colloid grinding technology to obtain a uniform emulsion; Process of colloid grinding: Set the distance between the stator and rotor of the colloid mill to 100 μm and grind for 15 minutes; then set the distance between the stator and rotor of the colloid mill to 60 μm and grind for 10 minutes to complete the colloid grinding treatment.

[0066] Step 4: First, heat the road petroleum asphalt to 150°C, then add the pre-prepared calcium nitrate powder and stir thoroughly to reach a uniform hot-melt state. Next, synchronously add the recycled polyurethane particles in a high-speed shearing device, and achieve uniform dispersion through the primary mechanical shearing effect to obtain the primary product of polyurethane-modified asphalt; Primary shearing process: Shear the hot-melt road petroleum asphalt at a speed of 2000 revolutions per minute for 10 minutes. During this process, gradually add the waste polyurethane powder. After both are completely added, continue the shearing process for 20 minutes until the shearing is fully completed.

[0067] Step 5: Conduct a second shearing treatment on the crude waste polyurethane-modified asphalt, and simultaneously add a cross-linking agent, a compatibilizer, and an emulsion. After shearing evenly, cool it to obtain the waste polyurethane-modified asphalt.

[0068] Secondary shearing process: Slowly add the cross-linking agent, the compatibilizer, and the emulsion. After the cross-linking agent, the compatibilizer, and the emulsion are added, continue the shearing treatment at a rate of 4000 r / min for 30 min to obtain the waste polyurethane-modified asphalt.

[0069] Example 4 This example provides a waste polyurethane-modified asphalt, and the difference between this example and Example 1 is only that: In this example, the road petroleum asphalt used is No. 50.

[0070] Use calcium chloride as a stabilizer, alkylamide polyamine emulsifier as a surfactant, and polyol (ethylene glycol) as a modifier.

[0071] Use aromatic oil as a compatibilizer and isocyanate (toluene diisocyanate (TDI)) as a cross-linking agent.

[0072] For the remaining types of raw materials, the addition ratios of the raw materials, and the preparation process are exactly the same as those in Example 1.

[0073] Example 5 This example provides a waste polyurethane-modified asphalt, and the difference between this example and Example 1 is only that: In this example, the road petroleum asphalt used is No. 90.

[0074] Use zinc chloride as a stabilizer and aminated lignin emulsifier as a surfactant.

[0075] Use vegetable oil as a compatibilizer and aziridine as a cross-linking agent.

[0076] For the remaining types of raw materials, the addition ratios of the raw materials, and the preparation process are exactly the same as those in Example 1.

[0077] Example 6 This example provides a waste polyurethane modified asphalt mixture, and its preparation method is as follows: S1. Weigh each preparation raw material according to the following ratio and set aside: 5 parts of the waste polyurethane modified asphalt prepared in Example 1, 90 parts of filled aggregate, 10 parts of mineral powder, and 5 parts of additive; Limestone powder with a particle size <0.075 is used as the mineral powder and added.

[0078] S2. Dry the weighed aggregate at a temperature of 150 °C for 40 min, add the additive and stir evenly, then keep it at a constant temperature to obtain the first mixture; It should be noted that in the present invention, the aggregate and the additive are graded in an intermittent grading manner to prepare the first mixture.

[0079] In this example, stirring can make the additive fully contact and mix with the coarse aggregate and fine aggregate. During the stirring process, the nano-zinc oxide material can increase the weak dispersion force between the asphalt and the aggregate and the free energy on the surface of the asphalt mixture, thereby enhancing the affinity between the asphalt and the aggregate, enhancing the adhesion ability of the aggregate and the waste polyurethane modified asphalt, and thus improving the high-temperature stability of the asphalt mixture and the anti-fracture performance of the road surface.

[0080] S3. Heat the waste polyurethane modified asphalt to 160 °C, then add the first mixture kept at a constant temperature and stir evenly to obtain the waste polyurethane modified asphalt mixture.

[0081] Example 7 This example provides a waste polyurethane modified asphalt mixture, and the difference in its preparation method from that of Example 6 is only that: In S1, the preparation raw materials are weighed according to the following ratio: 7 parts of the waste polyurethane modified asphalt prepared in Example 1, 100 parts of filled aggregate, 15 parts of mineral powder, and 2 parts of additive.

[0082] In S3, the waste polyurethane modified asphalt is heated to 180 °C and then added to the first mixture.

[0083] Example 8 This example provides a waste polyurethane modified asphalt mixture, and the difference in its preparation method from that of Example 6 is only that: In S1, the preparation raw materials are weighed according to the following ratio: 8 parts of the waste polyurethane modified asphalt prepared in Example 1, 120 parts of filled aggregate, 20 parts of mineral powder, and 3 parts of additive.

[0084] In S3, the waste polyurethane modified asphalt is heated to 170 °C and then added to the first mixture.

[0085] Example 9 This embodiment provides a waste polyurethane modified asphalt mixture, and the difference in its preparation method from that of Example 6 is only that: The waste polyurethane modified asphalt in this embodiment is the waste polyurethane modified asphalt prepared in Example 2.

[0086] Example 10 This embodiment provides a waste polyurethane modified asphalt mixture, and the difference in its preparation method from that of Example 6 is only that: The waste polyurethane modified asphalt in this embodiment is the waste polyurethane modified asphalt prepared in Example 3.

[0087] Comparative Example 1 This comparative example provides a waste polyurethane modified asphalt, and the difference between this comparative example and Example 1 is that: No modifier was added in this comparative example.

[0088] Specific raw material formula: 80 parts of 70# petroleum asphalt, 5 parts of waste polyurethane, 15 parts of calcium nitrate, 2 parts of compatibilizer naphthenic oil, 10 parts of crosslinking agent divinylbenzene, 0.5 part of stabilizer magnesium oxide, 1 part of surfactant quaternary ammonium salt emulsifier, and 30 parts of water.

[0089] Comparative Example 2 This comparative example provides a waste polyurethane modified asphalt, and the difference between this comparative example and Example 1 is that: No compatibilizer was added in this comparative example.

[0090] Specific raw material formula: 80 parts of 70# petroleum asphalt, 5 parts of waste polyurethane, 15 parts of calcium nitrate, 20 parts of modifier epoxy resin, 10 parts of crosslinking agent divinylbenzene, 0.5 part of stabilizer magnesium oxide, 1 part of surfactant quaternary ammonium salt emulsifier, and 30 parts of water.

[0091] Comparative Example 3 This comparative example provides a waste polyurethane modified asphalt, and the difference between this comparative example and Example 1 is that: No calcium nitrate was added in this comparative example.

[0092] Specific raw material formula: 80 parts of 70# petroleum asphalt, 5 parts of waste polyurethane, 20 parts of modifier epoxy resin, 2 parts of compatibilizer naphthenic oil, 10 parts of crosslinking agent divinylbenzene, 0.5 part of stabilizer magnesium oxide, 1 part of surfactant quaternary ammonium salt emulsifier, and 30 parts of water.

[0093] Comparative Example 4 This comparative example provides a waste polyurethane modified asphalt, and the difference between this comparative example and Example 1 is that: No surfactant was added in this comparative example.

[0094] The specific raw material formula is: 80 parts of 70# petroleum asphalt, 5 parts of waste polyurethane, 15 parts of calcium nitrate, 20 parts of modifier epoxy resin, 2 parts of compatibilizer cyclohexane oil, 10 parts of cross-linking agent divinylbenzene, 0.5 parts of stabilizer magnesium oxide and 30 parts of water.

[0095] Comparative Example 5 This comparative example provides a waste polyurethane modified asphalt mixture, and its preparation method is different from that of Example 6 only in that: In this comparative example, the waste polyurethane modified asphalt of comparative example 1 was used to prepare a waste polyurethane modified asphalt mixture.

[0096] Comparative Example 6 This comparative example provides a waste polyurethane modified asphalt mixture, and its preparation method is different from that of Example 6 only in that: In this comparative example, the waste polyurethane modified asphalt of comparative example 2 was used to prepare a waste polyurethane modified asphalt mixture.

[0097] Comparative Example 7 This comparative example provides a waste polyurethane modified asphalt mixture, and its preparation method is different from that of Example 6 only in that: In this comparative example, the waste polyurethane modified asphalt of comparative example 3 was used to prepare the waste polyurethane modified asphalt mixture.

[0098] Comparative Example 8 This comparative example provides a waste polyurethane modified asphalt mixture, and its preparation method is different from that of Example 6 only in that: In this comparative example, the waste polyurethane modified asphalt of comparative example 4 was used to prepare the waste polyurethane modified asphalt mixture.

[0099] Comparative Example 9 Compared with Example 1, the raw materials of a waste polyurethane modified asphalt provided in Comparative Example 9 only include waste polyurethane and petroleum asphalt.

[0100] Preparation process: waste polyurethane and petroleum asphalt are fully mixed to obtain waste polyurethane modified asphalt. Comparative Example 10 Compared with Example 1, Comparative Example 10 provides a waste polyurethane modified asphalt, in which only the raw material ratio is changed, as follows: 80 parts of 70# petroleum asphalt, 30 parts of waste polyurethane, 15 parts of calcium nitrate, 20 parts of modifier epoxy resin, 2 parts of compatibilizer cyclohexane oil, 10 parts of cross-linking agent divinylbenzene, 0.5 parts of stabilizer magnesium oxide, 1 part of surfactant which is a quaternary ammonium salt emulsifier and 30 parts of water.

[0101] Comparative Example 11 Compared with Example 1, Comparative Example 11 provides a waste polyurethane modified asphalt, in which only the raw material ratio is changed, as follows: 80 parts of 70# petroleum asphalt, 2 parts of waste polyurethane, 15 parts of calcium nitrate, 20 parts of modifier epoxy resin, 2 parts of compatibilizer naphthenic oil, 10 parts of crosslinking agent divinylbenzene, 0.5 part of stabilizer magnesium oxide, 1 part of surfactant quaternary ammonium salt emulsifier, and 30 parts of water.

[0102] Comparative Example 12 Compared with Example 1, a waste polyurethane modified asphalt provided by Comparative Example 12 only changed the raw material ratio, specifically as follows: 80 parts of 70# petroleum asphalt, 5 parts of waste polyurethane, 15 parts of calcium nitrate, 45 parts of modifier epoxy resin, 2 parts of compatibilizer naphthenic oil, 10 parts of crosslinking agent divinylbenzene, 0.5 part of stabilizer magnesium oxide, 1 part of surfactant quaternary ammonium salt emulsifier, and 30 parts of water.

[0103] Comparative Example 13 Compared with Example 1, a waste polyurethane modified asphalt provided by Comparative Example 13 only changed the raw material ratio, specifically as follows: 80 parts of 70# petroleum asphalt, 5 parts of waste polyurethane, 15 parts of calcium nitrate, 3 parts of modifier epoxy resin, 2 parts of compatibilizer naphthenic oil, 10 parts of crosslinking agent divinylbenzene, 0.5 part of stabilizer magnesium oxide, 1 part of surfactant quaternary ammonium salt emulsifier, and 30 parts of water.

[0104] Test In the present invention, the performance test results of Examples 1-10 and Comparative Examples 1-8 are as follows: (1) Technical performance test of waste polyurethane modified asphalt In the present invention, according to the test methods in JTG E20—2011 "Test Procedures for Bitumen and Bituminous Mixtures for Highway Engineering", the penetration, softening point, ductility at 5℃, and viscosity at 175℃ of the waste polyurethane modified asphalt of Examples 1-5 and Comparative Examples 1-4 were tested, and the results are shown in Table 1.

[0105] In addition, according to the test method of SH / T 0777-2005 "Determination of Rheological Properties of Bitumen (DSR Method)", dynamic shear rheological tests were carried out on Examples 1-5 and Comparative Examples 1-4, and the high-temperature performance of the asphalt was evaluated by the rutting factor ( ). Among them, the test temperature was 75℃.

[0106] Table 1 Test results of technical performance of modified asphalt

[0107] Combined with the technical requirements in CJJ / T 273—2019 "Technical Standard for Rubber Asphalt Pavement", it can be known that the performance of the waste polyurethane modified asphalt in Examples 1-5 all meets the technical requirements in the above standard. And from the test results of the technical performance of the above waste polyurethane modified asphalt, it can be seen that the modifier, compatibilizer, calcium nitrate and surfactant will all affect the performance of the waste polyurethane modified asphalt of the present invention, indicating that the performance of the waste polyurethane modified asphalt of the present invention is not achieved by a certain component, but by the synergistic effect among various components.

[0108] The test results are shown in Table 1. It can be clearly seen that the rutting resistance ability of the waste polyurethane modified asphalt obtained by the method of the present invention at high temperature is significantly improved, and this asphalt has excellent high-temperature performance.

[0109] (2) Road performance test of asphalt mixture The present invention respectively conducts rutting tests, beam bending tests, and immersion Marshall tests on the asphalt mixtures of Examples 6-10 and Comparative Examples 5-8 in this application according to the test methods in JTG E20—2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering", and further measures their high-temperature performance, low-temperature performance, and water stability performance. The results are shown in Table 2.

[0110] Table 2 Road performance test results of asphalt mixture

[0111] The road performance test results of the asphalt mixture in the present invention all meet the technical requirements of JTG F40—2004 "Technical Specifications for Construction of Highway Asphalt Pavements". By comparing the performance test results of the asphalt mixtures of Examples 6-10 and Comparative Examples 5-8, it can be known that: The asphalt mixture of the present invention has good high-temperature stability, good rutting resistance performance, and the low-temperature performance is improved; in addition, the addition of the modifier, compatibilizer, calcium nitrate and surfactant, as well as the particle size and dosage of the filled aggregate will all affect the performance of the asphalt mixture of the present invention. Thus, it shows that the performance of the asphalt mixture of the present invention is not achieved by a certain component, but by the synergistic effect among various components.

[0112] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A waste polyurethane modified asphalt, characterized in that: The following raw materials are prepared by weight: 80 to 120 parts of petroleum asphalt, 5 to 20 parts of waste polyurethane, 5 to 15 parts of calcium nitrate, 5 to 35 parts of modifier, 5 to 15 parts of cross-linking agent, 1 to 5 parts of compatibilizer, 1 to 5 parts of surfactant, and 15 to 60 parts of water.

2. The waste polyurethane modified asphalt according to claim 1, characterized in that: The following raw materials are prepared by weight: 100 to 120 parts of petroleum asphalt, 10 to 20 parts of waste polyurethane, 10 to 15 parts of calcium nitrate, 20 to 30 parts of modifier, 10 to 15 parts of cross-linking agent, 2 to 5 parts of compatibilizer, 1 to 3 parts of surfactant, and 40 to 50 parts of water.

3. The waste polyurethane modified asphalt according to claim 1 or 2, characterized in that: The modifier includes at least one of epoxy resin, polyol and amine compound; the crosslinking agent includes at least one of divinylbenzene, isocyanate and aziridine; the compatibilizer includes at least one of cycloalkane oil, aromatic oil and vegetable oil; the surfactant includes at least one of quaternary ammonium salt emulsifier, alkylamide polyamine emulsifier, aminated lignin emulsifier and sulfate ester emulsifier.

4. The waste polyurethane modified asphalt according to claim 1 or 2, characterized in that: It also includes 0.1 to 2 parts of a stabilizer; the stabilizer includes at least one of magnesium oxide, calcium chloride, zinc chloride, carbon black, calcium phosphate and barium sulfate.

5. A method for preparing waste polyurethane modified asphalt according to any one of claims 1 to 4, characterized in that: The following steps are involved: Mixing waste polyurethane with a modifier and subjecting it to ball milling to obtain a first material; Adding a stabilizer and a surfactant into water, and subjecting the mixture to colloid grinding, to obtain a second material; The petroleum asphalt is heated, calcium nitrate is added, mixed, and heated until melted, and the first material is added, and primary shearing and stirring is performed to obtain a third material; The third material is sheared for the second time, and a cross-linking agent and the second material are added simultaneously. If there is a compatibilizer, it is also added together. After the shearing is completed, it is cooled to room temperature to obtain waste polyurethane modified asphalt.

6. The method for preparing waste polyurethane modified asphalt according to claim 5, characterized in that: The temperature of heating treatment of petroleum asphalt is 140℃~180℃.

7. The method for preparing waste polyurethane modified asphalt according to claim 5, characterized in that: The rotation speed of the initial shearing is 1500r / min~3000r / min, and the time of the initial shearing is 30min~90min.

8. The method for preparing waste polyurethane modified asphalt according to claim 7, characterized in that: The rotation speed of the second shearing is 4000r / min~6000r / min, and the time of the second shearing is 30min~90min.

9. Use of the waste polyurethane modified asphalt according to any one of claims 1 to 4 or the waste polyurethane modified asphalt prepared by the preparation method according to any one of claims 5 to 8 in preparing asphalt mixture.

10. The use according to claim 9, characterized in that: The asphalt mixture is prepared from the following raw materials in parts by weight: 2 to 10 parts of waste polyurethane modified asphalt, 60 to 100 parts of aggregate, 5 to 10 parts of mineral powder, and 1 to 10 parts of additives.

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