High-viscosity and high-elasticity modified asphalt and its preparation method

Abstract

This invention provides a high-viscosity, high-elasticity modified asphalt and its preparation method, belonging to the field of asphalt production and manufacturing. The invention comprises: asphalt in a mass ratio of 100:6-18:0.1-3, a high-viscosity, high-elasticity asphalt modifier, and a stabilizer. The high-viscosity, high-elasticity asphalt modifier includes a novel thermoplastic elastomer, a moderately pyrolyzed rubber polymer, polyisobutylene rubber, a polymeric tackifier, and a second thermoplastic elastomer. The moderately pyrolyzed rubber polymer is obtained by mixing rubber powder and a second free radical scavenger through high-temperature pyrolysis. The novel thermoplastic elastomer is obtained by chemical grafting of the moderately pyrolyzed rubber polymer, a first thermoplastic elastomer, and a first free radical scavenger. The modified asphalt of this invention possesses excellent high and low temperature performance, stronger toughness / viscosity, and excellent dynamic viscosity at 60℃. It also exhibits stronger resistance to heat-oxidation / UV aging, significantly extending the service life of asphalt pavements.

Description

Technical Field

[0001] This invention relates to modified asphalt manufacturing technology, and more particularly to a high-viscosity, high-elasticity modified asphalt and its preparation method, belonging to the field of asphalt production and manufacturing technology. Background Technology

[0002] With the rapid development of highways in my country, many asphalt pavements have developed numerous defects before reaching their designed lifespan, seriously affecting vehicle driving quality. Scientific and reasonable maintenance can effectively improve the overall service level of the road surface, extend the time required for major and medium-sized repairs, and rationally utilize maintenance funds to extend the road's service life. For urban traffic pavements, while extending the road's service life, it is also necessary to consider the comfort of the living environment for urban residents—that is, considering both the pavement's lifespan and the comfort of the living environment—low ​​noise. Traditionally, when urban traffic pavements develop defects, the surface is typically milled one or two layers and then overlaid with asphalt concrete. This repair method is costly but ineffective, resulting in excessive road closures, high maintenance costs, and an inability to effectively reduce traffic noise on urban roads.

[0003] Currently, several technologies have emerged for urban road maintenance, including micro-surfacing, slurry seal, and navochip. Navochip, a rapid-construction maintenance method jointly developed by Koch Industries and Shell Asphalt, involves milling 2-3 cm of damaged pavement, then simultaneously spraying high-solids-content emulsified modified asphalt and paving concrete composed of high-viscosity, high-elasticity modified asphalt and aggregates. Compaction then forms an ultra-thin surface layer of approximately 2 cm. This ultra-thin surface layer offers significant noise reduction, largely due to the use of high-viscosity, high-elasticity modified asphalt. One method for preparing high-viscosity, high-elasticity modified asphalt involves using a Japanese TPS modifier combined with an elastomer polymer for composite modification. While this method produces high-viscosity modified asphalt with excellent performance, the high material cost makes widespread adoption more difficult. In recent years, domestic and international research institutions have successively developed products that use high-viscosity modified asphalt as the main modifier. These products effectively increase the low-temperature dynamic viscosity of asphalt without increasing its high-temperature rotational viscosity, thus achieving high-strength adhesion to aggregates without affecting construction characteristics. This method basically involves secondary processing of modified asphalt with 8-12% SBS and 4-8% high-viscosity, high-elasticity modifiers. However, SBS (styrene-butadiene-styrene block copolymer) has poor aging resistance, hindering the long-term construction of roads. Aging mainly involves the SBS modifier and the thermo-oxidative / UV aging of the asphalt. Thermo-oxidative / UV aging of the SBS modifier primarily involves the aging of the C=C double bonds in the butadiene segments, leading to a loss of elasticity and low-temperature performance. Thermo-oxidative / UV aging of the asphalt mainly involves the transformation of saturated / aromatic components into reclaimed / asphalt compounds during the process, causing the asphalt to harden and become brittle.

[0004] To improve the aging resistance of SBS-modified asphalt, domestic and international efforts currently focus on two main approaches. For the aging resistance of the C=C double bonds in the butadiene / isoprene block copolymer, hydrogenation is primarily used to convert the butadiene / isoprene segments into saturated CC segments, thus improving aging resistance. For the aging resistance of asphalt itself, the main approach involves adding large amounts of aromatic solvents and certain high-molecular-weight polymers. While existing techniques can delay the aging of modified asphalt, they do not fundamentally solve the problem of the elastomeric polymers' poor aging resistance. Summary of the Invention

[0005] This invention provides a novel high-viscosity, high-elasticity modified asphalt and its preparation method, which improves the comprehensive physical properties of the high-viscosity, high-elasticity modified asphalt, enhances its resistance to heat-oxidation / UV aging, and extends the service life of roads.

[0006] The high-viscosity, high-elasticity modified asphalt of this invention comprises: asphalt in a mass ratio of 100:6-18:0.1-3, a high-viscosity, high-elasticity asphalt modifier, and a stabilizer; the high-viscosity, high-elasticity asphalt modifier comprises: a novel thermoplastic elastomer, a moderately pyrolytic rubber polymer, polyisobutylene rubber (PIB), a polymeric tackifier, and a second thermoplastic elastomer in a mass ratio of 74.3-93.8:2.1-19.1:1-6:20-40:30-60;

[0007] Among them, the moderately pyrolyzed rubber polymer is prepared by mixing rubber powder and a second free radical scavenger in a mass ratio of 20-60:0.04-0.6 through stirring and high-temperature pyrolysis; the novel thermoplastic elastomer is prepared by chemical grafting of moderately pyrolyzed rubber polymer, a first thermoplastic elastomer, and a first free radical scavenger in a mass ratio of 20-60:40-80:0.2-0.6.

[0008] The first free radical scavenger and the second free radical scavenger are both any one or a combination of diphenylamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine (antioxidant CPPD), and 2,6-di-tert-butyl-4-methylphenol (antioxidant 264);

[0009] The first thermoplastic elasticity is any one or a combination of styrene-butadiene-styrene block copolymer (SBS) and styrene-isoprene-styrene (SIS);

[0010] The second thermoplastic elastomer is any one or a combination of ethylene propylene diene monomer (EPDM), ethylene-higher α-olefin random copolymer (thermoplastic elastomer POE), and olefin block copolymer (thermoplastic elastomer OBC).

[0011] The high-viscosity, high-elasticity modified asphalt described above, wherein the acetone-soluble content of the moderately cracked rubber polymer is ≤10% by weight, the trichloroethylene-soluble content is ≥90% by weight, the Mn of the trichloroethylene-soluble content is between 2000-5000 g / mol, and the polymer polydispersity index (PDI) is between 2.5-7.5.

[0012] The high-viscosity, high-elasticity modified asphalt described above, wherein the acetone-soluble content of the novel thermoplastic elastomer is ≤7% by weight, and the trichloroethylene-soluble content is ≥93% by weight; the trichloroethylene-soluble content has Mn between 100,000 and 550,000 g / mol and PDI between 2.0 and 5.0 by weight, which is between 80% and 95%.

[0013] The high-viscosity, high-elasticity modified asphalt described above, wherein the waste rubber powder is made from any one or more combinations of waste all-steel radial tires, waste semi-steel radial tires, and waste bicycle tires, and its particle size ranges from 40 to 100 mesh.

[0014] The high-viscosity, high-elasticity modified asphalt described above, wherein the polyisobutylene rubber has a Mn ≥ 10000 g / mol, preferably, the Mn is between 20000-45000 g / mol.

[0015] The high-viscosity, high-elasticity modified asphalt as described above, wherein the polymeric tackifier is any one or a combination of ethylene-acrylic acid copolymer (EAA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-butyl acrylate copolymer (EBA), and ethylene-methyl methacrylate copolymer (EMMA).

[0016] The high-viscosity, high-elasticity modified asphalt described above, wherein the asphalt is any one or more combinations of petroleum asphalt, coal tar pitch, and natural asphalt.

[0017] The high-viscosity, high-elasticity modified asphalt described above, wherein the stabilizer is any one or a combination of sulfur (S), TMTD, M-accelerator, and D-accelerator.

[0018] The present invention also provides a method for preparing the high-viscosity, high-elasticity modified asphalt as described above, comprising the following steps:

[0019] The rubber powder and the second free radical scavenger are put into a high-speed mixer and mixed for 15-35 minutes until the temperature of the mixed rubber powder is 105-135℃.

[0020] The mixed rubber powder is added to the first-stage screw extruder, and the temperature of the first-stage screw extruder is controlled at 380-430℃;

[0021] The material obtained from the first-stage screw extruder is continuously injected into the second-stage venting screw extruder. The first venting temperature zone of the venting screw extruder is controlled at 270-310℃ and a vacuum is applied with a vacuum degree of 10. -2 -10 -3 pa; The second exhaust temperature zone of the exhaust screw extruder is controlled at 190-230℃ and a vacuum is applied, with a vacuum degree of 10. -4 -10 -6 pa;

[0022] The first thermoplastic elastic and the first free radical scavenger are added to a high-speed mixer and mixed for 5-10 minutes until the material temperature reaches 60-90℃ to obtain mixture A;

[0023] The material and mixture A obtained from the second-stage exhaust extrusion are continuously injected into the third-stage screw extruder, and the temperature of the third-stage screw extruder is controlled at 190-230℃ to obtain the novel thermoplastic elastomer.

[0024] The polymeric tackifier, the second thermoplastic elastomer, polyisobutylene rubber (PIB), and the novel thermoplastic elastomer obtained by the third-stage extrusion mechanism are continuously injected into the fourth-stage screw extruder. The temperature of the fourth-stage screw extruder is controlled at 110-160℃ to extrude and obtain a high-viscosity and high-elasticity asphalt modifier.

[0025] The asphalt is heated to 155-185℃, and the high-viscosity and high-elasticity asphalt modifier is added. The mixture is kept at this temperature and stirred for 15-210 minutes at a temperature of 155-185℃ and a stirring rate of 500-1500 rpm. Subsequently, the mixture is sheared at a shear rate of 5000-12000 rpm for 15-50 minutes, during which a stabilizer is added.

[0026] High-viscosity and high-elasticity modified asphalt is obtained by stirring at 155-185℃ and a stirring rate of 500-1500rpm for 90-300 minutes.

[0027] In the method for preparing high-viscosity, high-elasticity modified asphalt as described above, the first-stage screw extruder is a twin-screw extruder or a three-screw extruder with a screw speed of 50-90 rpm; the second-stage screw extruder is a vented twin-screw extruder or a three-screw extruder with a screw speed of 40-70 rpm; the third-stage screw extruder is a twin-screw extruder or a three-screw extruder with a screw speed of 60-120 rpm; and the fourth-stage screw extruder is a twin-screw extruder or a three-screw extruder with a screw speed of 40-100 rpm.

[0028] The embodiments of the present invention have at least the following beneficial effects:

[0029] (1) The polymer molecular chain free radicals formed by the moderate cracking of rubber can exist relatively stably under high temperature and oxygen-free conditions because there is no participation of rubber desulfurizer and softening oil. A novel thermoplastic elastomer is prepared by molecular-level melt blending and grafting with styrene-butadiene block copolymer (SBS) / styrene-isoprene-styrene block copolymer (SIS). This novel thermoplastic elastomer has stronger resistance to thermo-oxidative / ultraviolet aging, which essentially improves the aging resistance of modifiers in modified asphalt. In addition, the molecular weight of the novel thermoplastic elastomer of this invention is significantly higher than that of SBS / SIS. When applied to modified asphalt, the cohesiveness, adhesion and cohesiveness of the asphalt are greatly improved. This leads to a significant improvement in the high and low temperature performance, toughness / visco-toughness, dynamic viscosity at 60℃ and water damage resistance of the modified asphalt.

[0030] (2) Furthermore, in the preparation process of the new thermoplastic elastomer, a free radical scavenger was introduced to effectively avoid oxidation caused by oxygen participation during the mixing and heating stage of waste rubber / SBS / SIS, and to ensure the activity of the moderately pyrolyzed rubber products and the molecular weight uniformity of SBS / SIS as much as possible, thereby increasing the molecular weight of the new thermoplastic elastomer and further improving the high and low temperature performance, toughness / viscosity, dynamic viscosity at 60℃, water damage resistance and aging resistance of the modified asphalt; a gradient vacuum treatment of the moderately pyrolyzed rubber mixture was introduced to separate the smaller molecular weight free radical fragments formed by the moderate pyrolysis of rubber as much as possible, retain the molecular weight uniform free radical fragments and react chemically with SBS / SIS, thereby increasing the molecular weight and uniformity (PDI) of the new thermoplastic elastomer and further improving the high and low temperature performance, toughness / viscosity, dynamic viscosity at 60℃, water damage resistance and aging resistance of the modified asphalt;

[0031] (3) In the preparation process of high viscosity and high elasticity asphalt modifier, an appropriate excess of organic polymer with a molecular weight between 2000-5000, which is separated from rubber by moderate cracking and gradient vacuum extraction, is introduced. The molecular weight of this polymer is similar to that of the aromatics / colloids in asphalt and has good low temperature flexibility. While effectively improving the heat and oxygen / ultraviolet aging resistance of the base asphalt, it can also effectively improve its resistance to low temperature cracking.

[0032] (4) In the preparation process of high-viscosity, high-elasticity asphalt modifier, a special elastomer polymer—polyisobutylene rubber—is introduced. Polyisobutylene has the chemical characteristics of saturated hydrocarbon compounds, with tightly and symmetrically distributed methyl groups on its side chains, making it a polymer with unique properties. One of the characteristics of polyisobutylene is its excellent self-healing ability and excellent puncture resistance; another characteristic is its good low-temperature flexibility and tackifying properties. The addition of polyisobutylene can further enhance the high-viscosity, high-elasticity modified asphalt's high and low temperature performance, toughness / viscosity toughness, dynamic viscosity at 60℃, water damage resistance, and aging resistance.

[0033] (5) In the preparation process of high viscosity and high elasticity asphalt modifier, a polymer tackifier and a second thermoplastic elastomer component are introduced. These two components have the characteristics of high temperature toughness and low temperature flexibility, and also have excellent polar adhesion. The synergistic effect of the two can further improve the viscosity and toughness of high viscosity and high elasticity modified asphalt, increase the cohesion of asphalt, but do not damage the low temperature crack resistance of asphalt.

[0034] Under the synergistic effect of the components of the high-viscosity and high-elasticity asphalt modifier mentioned above, when the high-viscosity and high-elasticity asphalt modifier of the present invention is applied to asphalt, it has both excellent comprehensive physical properties and good aging resistance, thereby improving the performance of asphalt pavement and extending the service life of the pavement. Detailed Implementation

[0035] The high-viscosity, high-elasticity modified asphalt and its preparation method described in this invention can be made using the following materials and components, but are not limited to them, such as: waste rubber, SBS, SIS, screw extruder, antioxidants, etc.

[0036] Examples 1-16

[0037] (1) Add 40-mesh rubber powder and the second free radical scavenger into a high-speed mixer and mix for 20 minutes until the temperature of the mixed rubber powder is 115℃.

[0038] (2) Add the mixed rubber powder to the first-stage screw extruder, and control the temperature of the first-stage extruder to 420℃ and the screw speed to 65rpm;

[0039] (3) The material obtained from the first-stage screw extruder is continuously injected into the second-stage venting screw extruder. The first venting temperature zone of the venting screw extruder is controlled at 290°C and a vacuum is drawn, with a vacuum degree of 0.006 Pa; the second venting temperature zone of the venting screw extruder is controlled at 220°C and a vacuum is drawn, with a vacuum degree of 10 Pa. -5 pa, screw speed 50 rpm;

[0040] (4) The first thermoplastic elastomer [SBS (Sinopec Yueyang Petrochemical, model: 791-H: Mn: 98000g / mol, PDI: 3.2, trichloroethylene soluble content: 100%) or SIS (Sinopec Yueyang Petrochemical, model: 1105, Mn: 185000, PDI: 3.6; trichloroethylene soluble content: 100%)] and the first free radical scavenger are added to a high-speed mixer and mixed for 7 minutes until the material temperature reaches 80℃ to obtain mixture A;

[0041] (5) The material and mixture A obtained from the second-stage exhaust extrusion machine are continuously injected into the third-stage screw extruder. The temperature of the third-stage screw extruder is controlled at 220°C and the screw speed is 85 rpm to obtain the novel thermoplastic elastomer.

[0042] (6) A high-molecular-weight tackifier, a second thermoplastic elastomer, polyisobutylene rubber (PIB) and a novel thermoplastic elastomer obtained by a third-stage extrusion machine are continuously injected into a fourth-stage screw extruder. The temperature of the fourth-stage screw extruder is controlled at 150°C and the screw speed is 60 rpm. A high-viscosity and high-elasticity asphalt modifier is obtained by extrusion.

[0043] The difference between Examples 1-16 lies in the types, composition, and proportions of raw materials used to prepare the high-viscosity, high-elasticity asphalt modifier; the preparation process is the same, as detailed in Table 1.

[0044]

[0045]

[0046] Table 1

[0047] Examples 17-30

[0048] (1) Add 35 parts by weight of 40 mesh all-steel tire rubber powder and 0.4 parts by weight of antioxidant 264 into a high-speed mixer and mix for 20 minutes until the temperature of the mixed rubber powder is 115℃.

[0049] (2) Add the mixed rubber powder to the first stage co-rotating parallel twin-screw extruder, adjust the temperature and speed of the first stage extruder, and obtain material A through mixing, conveying, shearing and pyrolysis;

[0050] (3) Material A is continuously injected into the second-stage venting screw extruder. The temperature and vacuum of the first and second temperature control zones of the venting screw extruder are adjusted, and the screw speed is adjusted to obtain material B.

[0051] (4) 65 parts by weight of SBS (Sinopec Yueyang Petrochemical, model: 791-H: Mn: 98000g / mol, PDI: 3.2, trichloroethylene soluble content: 100%) and 0.3 parts by weight of antioxidant 264 were put into a high-speed mixer and mixed for 7 minutes until the material temperature reached 80℃ to obtain mixture C;

[0052] (5) The material B and mixture C obtained from the second-stage exhaust extrusion machine are continuously injected into the third-stage screw extruder. The temperature and screw speed of the third-stage extruder are adjusted. After the material is melted and mixed and a grafting reaction occurs, a new thermoplastic elastomer is obtained.

[0053] (6) 30 parts by mass of EAA, 50 parts by mass of POE, 3 parts by mass of PIB and a new thermoplastic elastomer are continuously injected into the fourth stage extruder. The temperature and screw speed of the fourth stage extruder are adjusted, and the high viscosity and high elasticity asphalt modifier is obtained by extrusion.

[0054] The difference between Examples 17-30 lies in the different process parameters for preparing the high-viscosity, high-elasticity asphalt modifier, as detailed in Table 2:

[0055] Table 2

[0056]

[0057] For Examples 1-30, the novel thermoplastic elastomers taken from the end of the third-stage extruder were subjected to the following treatment:

[0058] First, acetone was used as the solvent, and Soxhlet extraction was performed continuously for 48 hours until the small organic molecules (acetone-soluble substances) were completely extracted and separated by acetone. Subsequently, the soluble fraction was dried in a vacuum drying oven until its mass remained constant, and the insoluble fraction was dried until its mass remained constant. Then, a second extraction was performed using trichloroethylene as the solvent to separate the large molecular soluble substances (trichloroethylene-soluble substances) and the insoluble substances.

[0059] The average molecular weight and polydispersity index (PDI) of trichloroethylene solubles were tested (GPC testing can simultaneously characterize molecular weight and PDI). The test method is as follows: the trichloroethylene solubles were fully swollen with toluene, and then the number average molecular weight (Mn) and polydispersity index (PDI) of each component of the sample were determined using a Waters 515-2410 GPC analyzer. The weight percentage of different molecular weight components was calculated by peak area. Tetrahydrofuran was used as the mobile phase, polystyrene was used as the standard, and the test temperature was 35℃.

[0060] Table 3

[0061]

[0062] As can be seen from the above embodiments:

[0063] (1) The rubber moderately pyrolyzed polymer and SBS / SIS were melt-blended in an oxygen-free and high-temperature environment. The product was not a simple physical blend of multiple materials. The weight percentage of the component with a smaller molecular weight was significantly lower than that at the time of feeding, while the weight percentage of the component with a larger molecular weight was significantly higher than that at the time of feeding. Its Mn was significantly larger than that of SBS / SIS, indicating that SBS / SIS and the rubber moderately pyrolyzed polymer under high temperature and oxygen-free conditions under these conditions had undergone a chemical reaction.

[0064] (2) During the process of melting and mixing of moderately pyrolyzed rubber polymer and first thermoplastic elastomer, free radical scavenger is more important to prevent oxidation protection of rubber powder pyrolysis and the heating process of first thermoplastic elastomer. The addition of free radical scavenger can consume the influence of oxygen / water and other substances that are easy to form free radicals in the raw materials to a greater extent, and reduce the influence on the molecular weight and molecular weight distribution of the new thermoplastic elastomer.

[0065] (3) Adding a gradient vacuum step to the second-stage extruder can effectively reduce the influence of free radicals of small organic molecules in moderately cracked rubber polymers on the molecular weight and molecular weight distribution of novel thermoplastic elastomers, and can significantly reduce the weight percentage of small organic molecules with smaller molecular weights in novel thermoplastic elastomers.

[0066] Preparation of high-viscosity and high-elasticity modified asphalt

[0067] Examples 31-64, Comparative Examples D1-D2:

[0068] The specific asphalt modification process is as follows: Qinhuangdao 70A base asphalt (from PetroChina Qinhuangdao Refinery, whose physical properties meet the technical requirements for base asphalt in JTG F40-2004) is heated to 180℃, and a high-viscosity, high-elasticity asphalt modifier or SBS / high-viscosity, high-elasticity modifier (commercially available) is added in measured amounts. The mixture is then kept at this temperature and stirred for 45 minutes at a stirring speed of 1000 rpm. The mixture is then sheared for 20 minutes using a high-speed shear emulsifier at a shear rate of 8000 rpm. A stabilizer (sulfur S) is added, and the mixture is kept at this temperature and stirred for 240 minutes at 180℃ at a stirring speed of 1000 rpm to obtain high-viscosity, high-elasticity modified asphalt. After completion, the performance indicators of each modified asphalt are tested.

[0069] The amounts of each raw material added in Examples 31 to 64 and Comparative Examples D1 to D2 are shown in Table 4, and the performance indicators of the modified asphalt in each example and comparative example are shown in Table 5.

[0070] Table 4

[0071]

[0072]

[0073] Table 5

[0074]

[0075]

[0076]

[0077] Note: The testing methods shall be in accordance with the relevant testing methods in the JTGE20-2011 standard.

[0078] The results of the high-viscosity, high-elasticity modified asphalt in the above embodiments show that:

[0079] Compared to the comparative example, the modified asphalt prepared by the high-viscosity and high-elasticity asphalt modifier of this invention exhibits significantly superior performance in key indicators reflecting the cohesiveness and adhesion / force of the high-viscosity and high-elasticity modified asphalt—60℃ dynamic viscosity, 25℃ viscosity-toughness, and 25℃ toughness—with a smaller addition ratio. The novel thermoplastic elastomer component in the high-viscosity and high-elasticity modifier of this invention has a higher molecular weight than traditional thermoplastic elastomers (SBS), resulting in greater cohesiveness of the modified asphalt. Through the synergistic effect of the three components—polyisobutylene rubber, high-molecular-weight tackifier, and advanced α-polyolefin elastomer—the high-temperature toughness of the modified asphalt is significantly increased, further enhancing the performance indicators such as 60℃ dynamic viscosity, 25℃ viscosity-toughness, and 25℃ toughness of the modified asphalt.

[0080] Compared to the comparative example, the modified asphalt prepared by the high-viscosity, high-elasticity asphalt modifier of this invention, with a smaller addition ratio, exhibits superior performance in terms of high-temperature properties (softening point) and low-temperature properties (5°C ductility) compared to traditional high-viscosity, high-elasticity modified asphalt. The high-viscosity, high-elasticity asphalt modifier of this invention comprises a novel thermoplastic elastomer as one component, which has a larger molecular weight and superior low-temperature flexibility, thus better improving the high and low temperature performance of asphalt compared to traditional SBS. The second component, a moderately pyrolytic rubber polymer, has a molecular weight similar to the aromatic components in asphalt and good low-temperature flexibility. Its synergistic effect with the novel thermoplastic elastomer further enhances its high and low temperature performance advantages. Furthermore, the third component, polyisobutylene rubber, a high-molecular-weight tackifier, and an advanced α-polyolefin elastomer, possesses excellent high-temperature toughness while maintaining good low-temperature flexibility. When applied to modified asphalt, it does not damage its low-temperature performance. Through synergistic action with the novel thermoplastic elastomer component, the high-viscosity, high-elasticity modified asphalt exhibits even more outstanding high and low temperature performance.

[0081] Compared to the comparative example, the modified asphalt prepared by the high-viscosity, high-elasticity asphalt modifier of this invention exhibits superior aging resistance (post-aging ductility and 25°C penetration retention rate) with a lower addition ratio, and the performance degradation after aging is smaller. One component of the high-viscosity, high-elasticity asphalt modifier of this invention is a novel thermoplastic elastomer, which, after grafting with a moderately pyrolytic polymer of rubber,…

[0082] The content of C=C double bonds in its main chain is significantly reduced or even disappears after the reaction, resulting in superior resistance to thermo-oxidative and UV aging. The second component, a moderately pyrolyzed polymer, has a molecular weight similar to the aromatic components in asphalt, effectively compensating for changes in composition during the asphalt aging process. The third component, polyisobutylene rubber, high-molecular-weight tackifier, and advanced α-polyolefin elastomer, has a main chain primarily composed of saturated C=C bonds with very low C=C double bond content. Through the synergistic effect of the components of the high-viscosity, high-elasticity asphalt modifier, the modified asphalt exhibits superior resistance to thermo-oxidative and UV aging.

[0083] To illustrate the beneficial effects of the high-viscosity, high-elasticity asphalt prepared by the present invention when applied to asphalt concrete, the following exemplary comparison of the performance of asphalt concrete prepared by the high-viscosity, high-elasticity modified asphalt of the present invention and asphalt concrete prepared by conventional high-viscosity, high-elasticity modified asphalt is provided.

[0084] The high-viscosity, high-elasticity modified asphalt prepared in Example 35 and Comparative Example 1 / 2 were mixed with aggregates (stone) to prepare SMA-13 ​​type asphalt mastic structured asphalt mixture and OGFC-13 type open-graded drainage asphalt mixture, respectively. The performance of the asphalt mixtures was tested, and the results are as follows (the asphalt mixture preparation process and method were in accordance with JTG F40-2004 Technical Specification for Construction of Highway Asphalt Pavement, and the testing method was in accordance with JTG E20-2011 Test Procedure for Asphalt and Asphalt Mixtures in Highway Engineering).

[0085] SMA-13:

[0086] Table 6

[0087]

[0088]

[0089] OGFC-13

[0090] Table 7

[0091]

[0092] The results of the above implementation cases in asphalt mixtures show that:

[0093] The high-viscosity, high-elasticity modified asphalt provided by this invention possesses stronger cohesion and excellent toughness / visco-toughness, which is reflected in the mixture performance as higher high-temperature performance (dynamic stability at 60℃) and better water damage resistance (water immersion Marshall residual strength ratio / freeze-thaw splitting residual strength ratio). In particular, in SMA-type asphalt mastic asphalt mixtures / OGFC-type open-graded drainage asphalt mixtures, the bonding between aggregates relies more on the cohesion of the asphalt itself. Modified asphalt with greater cohesion results in less Schellenberg segregation loss and Kentenberg dispersion loss in the asphalt mixture. The pavement formed after paving and compaction of the asphalt mixture has more durable adhesion without causing aggregate loosening. Furthermore, in terms of the low-temperature crack resistance of asphalt mixtures, the novel thermoplastic elastomer, one of the components of the high-viscosity and high-elasticity asphalt modifier in this technical solution, has a larger molecular weight and superior low-temperature flexibility, which can better improve the low-temperature performance of asphalt. The second component, polyisobutylene rubber, polymeric tackifier, and advanced α-polyolefin elastomer, possess excellent high-temperature toughness while also taking into account low-temperature flexibility. When applied to modified asphalt, it does not damage its low-temperature performance. Under the synergistic effect of the novel thermoplastic elastomer component, the low-temperature performance of the high-viscosity and high-elasticity modified asphalt is more prominent, and the low-temperature crack resistance of the asphalt mixture is more excellent.

[0094] The sequence numbers of the above embodiments of the present invention are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of some modifications and the superposition of necessary general technologies; of course, they can also be implemented by simplifying some important technical features. Based on this understanding, the technical solution of the present invention, in essence or the part that contributes to the prior art, is: the overall structure and connection method, and the structure described in the various embodiments of the present invention.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-sticky high-elasticity modified asphalt, characterized in that, include: Asphalt, high-viscosity and high-elasticity asphalt modifiers and stabilizers with a mass ratio of 100:6-18:0.1-3; The high-viscosity, high-elasticity asphalt modifier comprises: a novel thermoplastic elastomer, a moderately pyrolytic rubber polymer, polyisobutylene rubber, a high-molecular-weight tackifier, and a second thermoplastic elastomer in a mass ratio of 74.3-93.8:2.1-19.1:1-6:20-40:30-60; Among them, the moderately pyrolyzed rubber polymer is prepared by mixing rubber powder and a second free radical scavenger in a mass ratio of 20-60:0.04-0.6 through stirring and high-temperature pyrolysis; the novel thermoplastic elastomer is prepared by chemical grafting of moderately pyrolyzed rubber polymer, a first thermoplastic elastomer, and a first free radical scavenger in a mass ratio of 20-60:40-80:0.2-0.

6. The first free radical scavenger and the second free radical scavenger are both combinations of one or more of diphenylamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, and 2,6-di-tert-butyl-4-methylphenol; The first thermoplastic elasticity is any one or a combination of styrene-butadiene-styrene block copolymer and styrene-isoprene-styrene; The second thermoplastic elastomer is any one or a combination of ethylene propylene diene monomer (EPDM), ethylene-higher α-olefin random copolymer, and olefin block copolymer.

2. The high-viscosity high-elasticity modified asphalt according to claim 1, characterized in that, The moderately cracked rubber polymer has an acetone-soluble content of ≤10% by weight, a trichloroethylene-soluble content of ≥90% by weight, a Mn content of trichloroethylene-soluble matter between 2000-5000 g / mol, and a polymer polydispersity index between 2.5-7.

5.

3. The high-viscosity high-elasticity modified asphalt according to claim 2, characterized by, The novel thermoplastic elastomer has an acetone-soluble content of ≤7% by weight and a trichloroethylene-soluble content of ≥93% by weight; the trichloroethylene-soluble content has a Mn content between 100,000 and 550,000 g / mol and a PDI content between 2.0 and 5.0 by weight, which is between 80% and 95%.

4. The high-viscosity high-elasticity modified asphalt according to claim 1, characterized by, The waste rubber powder is made from any one or more of waste all-steel radial tires, waste semi-steel radial tires, and waste bicycle tires, and its particle size ranges from 40 to 100 mesh.

5. The high-viscosity high-elasticity modified asphalt according to claim 1, wherein The polyisobutylene rubber has an Mn ≥ 10000 g / mol, preferably between 20000-45000 g / mol.

6. The high-viscosity high-elasticity modified asphalt according to claims 1 to 5, characterized by, The polymeric tackifier is any one or a combination of ethylene-acrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, and ethylene-methyl methacrylate copolymer.

7. The high-viscosity high-elasticity modified asphalt according to claims 1 to 5, characterized by, The asphalt is any one or a combination of petroleum asphalt, coal tar pitch, and natural asphalt.

8. The high-viscosity high-elasticity modified asphalt according to claims 1-5, characterized in that, The stabilizer is any one or a combination of sulfur, TMTD, M-promoter, and D-promoter.

9. A process for preparing the high-sticky high-elasticity modified asphalt as claimed in any one of claims 1 to 8, characterized by, Includes the following steps: The rubber powder and the second free radical scavenger are put into a high-speed mixer and mixed for 15-35 minutes until the temperature of the mixed rubber powder is 105-135℃. The mixed rubber powder is added to the first-stage screw extruder, and the temperature of the first-stage screw extruder is controlled at 380-430℃; The material produced by the first-stage screw extruder is continuously injected into the second-stage vented screw extruder, the first venting temperature zone of the vented screw extruder is controlled to be 270-310 ℃ and vacuum is drawn, the vacuum degree is 10 -2 -10 -3 pa; the second venting temperature zone of the vented screw extruder is controlled to be 190-230 ℃ and vacuum is drawn, the vacuum degree is 10 -4 -10 -6 pa; The first thermoplastic elastic and the first free radical scavenger are added to a high-speed mixer and mixed for 5-10 minutes until the material temperature is 60-90℃ to obtain mixture A; The material and mixture A obtained from the second-stage exhaust extrusion are continuously injected into the third-stage screw extruder, and the temperature of the third-stage screw extruder is controlled at 190-230℃ to obtain the novel thermoplastic elastomer. The polymeric tackifier, the second thermoplastic elastomer, the polyisobutylene rubber, and the novel thermoplastic elastomer obtained by the third-stage extrusion mechanism are continuously injected into the fourth-stage screw extruder. The temperature of the fourth-stage screw extruder is controlled at 110-160℃ to extrude and obtain a high-viscosity and high-elasticity asphalt modifier. The asphalt is heated to 155-185℃, and the high-viscosity and high-elasticity asphalt modifier is added. The mixture is kept at this temperature and stirred for 15-210 minutes at a temperature of 155-185℃ and a stirring rate of 500-1500 rpm. Subsequently, the mixture is sheared at a shear rate of 5000-12000 rpm for 15-50 minutes, during which a stabilizer is added. High-viscosity and high-elasticity modified asphalt is obtained by stirring at 155-185℃ and a stirring rate of 500-1500rpm for 90-300 minutes.

10. The method of claim 9, wherein the high viscosity high elasticity modified asphalt is prepared by adding the high viscosity high elasticity modifier to the base asphalt at a temperature of 150°C or higher. The first-stage screw extruder is a twin-screw extruder or a three-screw extruder with a screw speed of 50-90 rpm; the second-stage screw extruder is a vented twin-screw extruder or a three-screw extruder with a screw speed of 40-70 rpm; the third-stage screw extruder is a twin-screw extruder or a three-screw extruder with a screw speed of 60-120 rpm; and the fourth-stage screw extruder is a twin-screw extruder or a three-screw extruder with a screw speed of 40-100 rpm.

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