Energy-saving environment-friendly durable high-viscosity modified asphalt and preparation process thereof

Abstract

The invention relates to the technical field of asphalt material modification preparation, in particular to energy-saving environment-friendly durable high-viscosity modified asphalt and a preparation process thereof. Comprising the following components in parts by mass: 100 parts of matrix asphalt, 0.8-1.2 parts of nano cellulose, 4-6 parts of bio-based epoxy resin, 0.3-0.5 part of an ionic liquid, 0.5-0.8 part of a hindered phenol antioxidant and 1-2 parts of a compatilizer, the ionic liquid is adopted to disperse the nano cellulose and is matched with the bio-based epoxy resin at the same time, so that the dispersion uniformity of the nano cellulose in the asphalt is improved; the compatibility of the epoxy resin and the asphalt is enhanced, so that the viscosity of the asphalt is further improved, and the softening point, the viscosity, the anti-rutting factor and other properties of the asphalt are enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of modified preparation of asphalt materials, and particularly relates to energy-saving, environment-friendly, durable and highly viscous modified asphalt and its preparation process. Background Art

[0002] Asphalt is a dark brown to black viscous liquid or semi-solid substance, mainly composed of hydrocarbons and their derivatives, and has good adhesiveness, waterproofness and corrosion resistance, and is widely used in engineering construction and industrial fields.

[0003] When asphalt is used as an engineering construction material for road paving, the viscosity of asphalt is an important performance index determining the quality of road paving. Improving the viscosity has the following promoting effects: First, reduce the shedding or loosening of aggregates and improve the integrity of the mixture.

[0004] Second, improve the high-temperature stability and reduce rutting diseases.

[0005] Third, enhance the low-temperature crack resistance and delay the generation of cracks.

[0006] Fourth, improve the water damage resistance and reduce pavement damage.

[0007] The existing methods for adjusting the viscosity of asphalt are mostly modification treatments. For example, in the invention patent with the patent application number 202410591394.6, a road-use rut-resistant asphalt mixture and its preparation method are specifically disclosed. By weight, it includes the following components: 10-20 parts of matrix asphalt, 70-90 parts of aggregate, 5-10 parts of nano-level filler, 5-10 parts of amino-functionalized nano-cellulose whiskers, 3-5 parts of polymer elastomer, 1-1.5 parts of carboxyl-terminated liquid nitrile rubber, 1-3 parts of epoxy resin, and 0.1-0.5 parts of epoxy resin curing agent. The asphalt mixture prepared by the present invention has excellent performance in all aspects. Moreover, through performance tests, it can be seen that the addition of nano-montmorillonite, amino-functionalized nano-cellulose whiskers, polymer elastomer, and carboxyl-terminated liquid nitrile rubber has played a positive role in improving the performance of the asphalt mixture. Among them, the hydrogen bond network of amino-functionalized nano-cellulose whiskers and the chemical cross-linking of epoxy resin have simultaneously improved the viscosity and toughness of asphalt.

[0008] However, the technology of nano-cellulose modified asphalt needs to rely on surface modification (such as TEMPO oxidation) or complex processes (such as ethanol replacement) to solve its dispersion problem in asphalt. At the same time, the compatibility between epoxy resin and asphalt is another key factor restricting the further improvement of asphalt viscosity.

[0009] Therefore, there is an urgent need for a technical solution that can solve the above problems and further improve the viscosity of asphalt. Summary of the Invention

[0010] In view of the above problems, the present invention provides an energy-saving, environmentally friendly, durable and highly viscous modified asphalt and its preparation process. By using ionic liquid to disperse nanocellulose and simultaneously cooperating with bio-based epoxy resin, the dispersion uniformity of nanocellulose in asphalt is improved, the compatibility between epoxy resin and asphalt is enhanced, and further the viscosity of asphalt is improved, and the properties such as softening point, viscosity and rutting factor of asphalt are enhanced.

[0011] To achieve the above object, the present invention provides the following technical solutions: An energy-saving, environmentally friendly, durable and highly viscous modified asphalt, comprising the following components in parts by mass: 100 parts of matrix asphalt, 0.8 - 1.2 parts of nanocellulose, 4 - 6 parts of bio-based epoxy resin, 0.3 - 0.5 parts of ionic liquid, 0.5 - 0.8 parts of hindered phenol antioxidant, and 1 - 2 parts of compatibilizer.

[0012] Preferably, the matrix asphalt includes one or more selected from 50#, 70#, 90# or 110# road petroleum asphalt.

[0013] Preferably, when multiple matrix asphalts are compounded, the mass ratio of each asphalt component is (50 - 100):(0 - 50), and the penetration coefficient of the compounded asphalt ≤ 5%.

[0014] Preferably, the four-component composition of the matrix asphalt needs to satisfy saturates 20 - 35%, aromatics 30 - 45%, resins 20 - 30%, and asphaltenes 5 - 15%.

[0015] Saturates and aromatics, as the low-molecular components of asphalt, provide a dispersion medium for nanocellulose and epoxy resin; resins (20 - 30%) act as a "peptizing carrier", adsorbing asphaltenes (5 - 15%) through polar groups to form a stable colloidal structure. If the asphaltene content is too high (>15%), it is easy to cause agglomeration of nanocellulose; if it is too low (<5%), there will be insufficient crosslinking sites.

[0016] Preferably, the penetration of the matrix asphalt is 50 - 110 (25°C, 100g, 5s, 0.1mm); the softening point ≥ 46°C (Ring and Ball method), the ductility ≥ 100 cm (15°C, 5 cm / min), the flash point ≥ 260°C (COC), and the wax content ≤ 2.2% (distillation method).

[0017] The penetration of 50 - 110 of the matrix asphalt covers the requirements of different climate zones. When compounding, by controlling the penetration coefficient ≤ 5%, the molecular weight distribution of the mixed asphalt is ensured to be uniform, and segregation of the modifier in high and low molecular weight components is avoided. For example, when 70# and 90# asphalts are compounded at a ratio of 7:3, the high-temperature viscosity and low-temperature toughness can be balanced.

[0018] Preferably, the nanocellulose is nanofibrillated cellulose (NFC). The specific surface area of the nanofibrillated cellulose (NFC) is ≥100 m² / g, the nanoscale diameter is 5 - 50 nm, the aspect ratio is ≥20, and the crystallinity is ≥50%.

[0019] Specific surface area ≥100 m² / g: The high specific surface area provides more hydrogen bonding sites. Each gram of nanocellulose can adsorb 15 - 20 g of asphaltene to form a "nano-enhanced core".

[0020] Diameter 5 - 50 nm, aspect ratio ≥20: The one-dimensional nanostructure forms a "bridging network" in the asphalt. When the content reaches 1.0 part, physical cross-linking points throughout the system can be constructed, increasing the elastic recovery rate of the asphalt by 30%.

[0021] Crystallinity ≥50%: The rigid chain segments in the crystalline region inhibit the slippage of molecular chains, and the hydroxyl groups in the amorphous region promote hydrogen bonding with the epoxy resin, achieving an enhanced effect of "rigidity and flexibility combined".

[0022] Preferably, the bio-based epoxy resin is a cashew shell liquid modified epoxy resin. The epoxy value of the cashew shell liquid modified epoxy resin is 0.2 - 0.4 mol / 100 g, the viscosity is 500 - 2000 mPa·s, and the hydroxyl content is 1.5 - 3.0 mmol / g.

[0023] Epoxy value (determined by GB / T1677 - 2008): 0.2 - 0.4 mol / 100 g, ensuring the cross-linking reaction activity with the polar components of the asphalt; Viscosity (25°C, rotational viscometer): 500 - 2000 mPa·s, ensuring uniform dispersion in the asphalt system; Hydroxyl content (chemical titration method): 1.5 - 3.0 mmol / g, enhancing the interfacial adhesion by forming hydrogen bonds between the hydroxyl groups and the acidic groups of the asphalt.

[0024] The existing technologies for modifying asphalt with bio-based epoxy resins (such as the invention patent with patent application number CN117487369A) mainly use curing agents such as pentamethylenediamine and do not involve cashew shell liquid modified epoxy resins. The cashew shell liquid modified epoxy resin has a natural phenolic structure, which not only enhances the compatibility with the asphalt but also realizes the high-value utilization of agricultural waste.

[0025] Specifically, the main component of the cashew shell liquid is cardanol (a natural phenolic compound containing an unsaturated long carbon chain, with the structure as follows): HO—C6H4—(CH2) 15 —CH=CH—CH2—CH=CH—CH3.

[0026] The phenolic hydroxyl groups in its molecule can form hydrogen bond interactions with the carbonyl group (C=O) and hydroxyl group (—OH) of the polar components in asphalt (such as asphaltenes and resins), while the long-chain alkyl groups and unsaturated double bonds are compatible with the non-polar components of asphalt (such as saturates and aromatics) through van der Waals forces, forming a dual-adapted structure of "polar anchoring - non-polar dispersion", which improves the dispersion stability of epoxy resin in asphalt by more than 70% (compared with unmodified epoxy resin).

[0027] The interfacial tension between the modified epoxy resin and asphalt is about 12 - 15 mN / m, while it drops to 5 - 8 mN / m after being modified with cashew shell liquid (calculated by the Owens-Wendt equation). The low interfacial tension promotes the molecular-level diffusion of epoxy resin in asphalt, changing the compatibility between the modifier and asphalt from "phase separation type" to "semi-miscible type". Microstructural observation shows that the dispersed phase size decreases from 5 - 10 μm to 1 - 2 μm, and there is no obvious interfacial boundary.

[0028] The epoxy groups (—O—) in the cashew shell liquid-modified epoxy resin can undergo ring-opening addition reactions with the acidic groups in asphaltenes (such as carboxylic acids and phenols) under the thermal oxygen environment of asphalt to form covalent bond connections (the reaction formula is as follows): R-COOH + CH2-CH-O- → R-COO-CH2-CH-OH This chemical cross-linking effect constructs a three-dimensional network structure in asphalt, significantly increasing the resistance to molecular chain movement. Compared with unmodified epoxy resin, the viscosity of the modified asphalt at 60℃ increases from 12000 mPa·s to 22000 mPa·s, and the viscosity-temperature sensitivity (viscosity-temperature index) decreases by 35%, that is, the viscosity retention ability at high temperatures is stronger.

[0029] Furthermore, the synergistic viscosity increase of physical entanglement and hydrogen bond network, the molecular entanglement of long carbon chains, and the C15 long chain of cashew shell liquid form a "molecular bridge" in asphalt, entangling with the high-molecular-weight components of asphalt (such as asphaltenes), increasing the internal frictional resistance; The expansion of the hydrogen bond network, the phenolic hydroxyl groups form a cross-phase hydrogen bond network with the hydroxyl groups (—OH) of nanocellulose and the polar groups of asphalt, forming "physical anchor points" among the modifier - asphalt - nanocellulose, further restricting the movement of molecular chains; This physical-chemical synergistic effect enables the ductility of asphalt at 5℃ to still remain ≥30 cm (the traditional high-viscosity asphalt is only 15 - 20 cm), that is, it still maintains excellent toughness at high viscosity, breaking the traditional contradiction of "viscosity - toughness".

[0030] In addition, during the anti-aging process, regarding the viscosity stability, the natural antioxidant groups in the cashew shell liquid (such as catechol structure) and the hindered phenol antioxidant (Irganox 1010) act synergistically to inhibit the volatilization of light components and the molecular chain breakage caused by asphalt oxidation. After the accelerated aging test (RTFOT+PAV), the viscosity retention rate of the asphalt of the present invention at 60°C is ≥85%, while that of the traditional SBS modified asphalt is only 60-70%, indicating that the viscosity attenuation during long-term use is significantly slowed down.

[0031] Preferably, the ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate, with a surface tension of 40-50 mN / m and a viscosity of 300-500 mPa·s at room temperature; The hindered phenol antioxidant is antioxidant 1010; The compatibilizer is maleic anhydride grafted polyethylene, with a maleic anhydride grafting rate of 1.0%-2.5% and a melt flow rate of 1-5 g / 10 min (MFR, 190°C / 2.16 kg).

[0032] Specific effects of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6): Reducing the interfacial energy: The cations and anions ([BMIM]+ / [PF6]-) of the ionic liquid are adsorbed on the surface of nanocellulose, reducing the interfacial tension between cellulose and asphalt from 35 mN / m to 12 mN / m, and reducing the shear energy required for dispersion by 40%.

[0033] Electrostatic stabilization effect: The positively charged imidazole cation forms an electric double layer with the negatively charged cellulose hydroxyl group (ζ potential ≥ +25 mV), inhibiting the agglomeration of nanofibers, and making the sedimentation rate of the dispersion <5% after standing for 72 h (the sedimentation rate of the traditional dispersion method >30%).

[0034] The hindered phenol antioxidant 1010 prolongs the induction period to 60 min (only 30 min for traditional asphalt) by capturing the alkyl radicals (ROO·) generated by asphalt oxidation; the imidazole cation of the ionic liquid forms a π-π conjugation with the nitrogen heterocycle of asphaltene, inhibiting the coagulation of asphaltene during oxidation, and the viscosity growth rate after aging ≤15% (≥30% for traditional modified asphalt).

[0035] In addition, the present application adopts the construction of a triple synergistic enhancement mechanism: Physical enhancement: The high specific surface area and hydrogen bond network of nanocellulose form physical cross-linking points, inhibiting the high-temperature flow of asphalt (raising the softening point to ≥90°C).

[0036] Chemical cross-linking: The cashew shell liquid modified epoxy resin reacts with the polar components in asphalt to form a three-dimensional network structure (the rutting resistance factor ≥5.0 kPa, a 66% increase compared to traditional SBS modified asphalt).

[0037] Interface optimization: Ionic liquids promote the uniform dispersion of nanocellulose and epoxy resin by reducing the interfacial energy and electrostatic interaction, and enhance the interfacial bonding force between the two and asphalt (the interfacial bonding strength is increased by more than 40%).

[0038] This synergistic mechanism makes the viscosity (≥20000 mPa·s at 60 °C) and ductility (≥30 cm at 5 °C) of the present invention significantly better than those of the prior art, while the synergistic effect of nanocellulose and epoxy resin in existing patents (such as CN118344057B) only shows a single performance improvement (such as the softening point of about 80 °C).

[0039] The core innovation of this modification technology lies in utilizing the self-compatibilizing characteristics of the natural phenolic structure to achieve high-performance modification without the need to add additional compatibilizers.

[0040] Preferably, the modification method of the cashew nut shell liquid modified epoxy resin includes the following steps: Step a1, pretreatment of cashew nut shell liquid: The cashew nut shell liquid is vacuum dried at 60 - 80 °C for 2 - 3 hours to remove moisture and low-boiling impurities; Step a2, prepolymerization reaction: The cashew nut shell liquid and bisphenol A epoxy resin are fed in a mass ratio of 1:(2 - 3), and 0.5 - 1.0% of p-toluenesulfonic acid catalyst is added based on the total mass. The temperature is raised to 120 - 140 °C, and the reaction is stirred for 2 - 3 hours under nitrogen protection to obtain a cashew nut shell liquid grafted epoxy resin intermediate; Step a3, epoxy group adjustment: Epichlorohydrin is added to the intermediate, and the mass of epichlorohydrin accounts for 5 - 10% of the mass of the intermediate. Under the catalysis of a 10 - 15% NaOH aqueous solution, the epoxidation reaction is carried out at 50 - 60 °C for 1 - 2 hours to adjust the epoxy value to 0.2 - 0.4 mol / 100 g; Step a4, solvent removal: The reaction product in step a3 is distilled at 100 - 120 °C and a vacuum degree of ≤10 kPa for 30 - 60 min to remove the residual solvent, and the target modified epoxy resin is obtained.

[0041] The innovation points of the cashew nut shell liquid modification process are as follows: 1. Pretreatment for impurity removal (vacuum drying at 60 - 80 °C) to remove moisture (≤0.5%) and low-boiling fatty acids in the cashew nut shell liquid, avoiding the generation of by-products (such as esters) in subsequent reactions and ensuring the purity of epoxy groups.

[0042] 2. Grafting prepolymerization reaction (cashew nut shell liquid: bisphenol A epoxy = 1:2 - 3): The phenolic hydroxyl group of cardanol undergoes ring-opening addition with the epoxy group, introducing a C15 long carbon chain into the main chain of the epoxy resin (the reaction conversion rate ≥90%), and increasing the matching degree of the solubility parameter of the modified epoxy resin with asphalt from 0.82 to 0.95 (Hansen solubility parameter method).

[0043] 3. Precise regulation of epoxy value (0.2 - 0.4 mol / 100 g). Through the secondary epoxidation of epichlorohydrin, the epoxy groups consumed in the grafting reaction are replenished to ensure that every 100 g of resin contains 20 - 40 mmol of active epoxy groups, forming a stoichiometric match with the carboxylic acid groups of asphaltenes (about 15 - 25 mmol / 100 g of asphalt), and maximizing the crosslinking density.

[0044] In addition, the present invention also provides a process for preparing the energy-saving, environmentally friendly, durable and highly viscous modified asphalt described in any one of the above, including the following steps: Step t1. Matrix asphalt pretreatment: Heat the matrix asphalt to 160 - 170 °C, add ionic liquid, and stir at 800 - 1000 r / min for 15 min to promote the uniform dispersion of the ionic liquid. Step t2. Nanocellulose dispersion: Mix nanocellulose with a compatibilizer, add an appropriate amount of xylene and ultrasonically disperse for 30 min at a power of 200 - 300 W to form a stable suspension. Add the suspension to the pretreated asphalt, heat up to 170 - 180 °C, and perform high-speed shearing at 5000 - 6000 r / min for 30 min to make the nanocellulose evenly distributed. Step t3. Bio-based epoxy resin blending: Heat the bio-based epoxy resin to 120 - 130 °C, slowly add it to the asphalt system, maintain the temperature at 170 - 180 °C, and shear at 3000 - 4000 r / min for 20 min to promote the crosslinking reaction. Step t4. Antioxidant addition and ultrasonic treatment: Add a hindered phenol antioxidant, continue stirring for 10 min, and use an ultrasonic processor to perform secondary dispersion on the asphalt at a power of 300 - 400 W, a frequency of 20 - 40 kHz, and a treatment time of 15 min to further refine the microstructure. Step t5. Cooling and detection: Naturally cool to room temperature, and test the softening point, Brookfield viscosity, and ductility at 5 °C to ensure that the performance meets the standards.

[0045] Step-by-step dispersion-crosslinking process design (steps t1 - t4): Ionic liquid pretreatment (step t1): The ionic liquid melts and penetrates the asphaltene micelles at 160 - 170 °C, reducing the average particle size of asphaltenes from 500 nm to below 200 nm, providing space for subsequent insertion of nanocellulose. The stirring speed of 800 - 1000 r / min avoids shear overheating (temperature rise ≤ 5 °C) and protects the structure of the ionic liquid from decomposition.

[0046] Nanocellulose-compatibilizer synergistic dispersion (step t2): Xylene, as a "bridge solvent", dissolves the compatibilizer (MAPE) and swells the surface of nanocellulose. Ultrasonic treatment (200 - 300W) enables the maleic anhydride groups of MAPE to form ester bonds with cellulose hydroxyl groups (reaction degree ≥ 30%), improving the lipophilicity of the cellulose surface.

[0047] During high-speed shearing at 5000 - 6000 r / min, the shear stress (≥ 100 kPa) destroys the hydrogen bond aggregates of nanocellulose, causing it to disperse in the form of single filaments. The dispersion uniformity is detected by a laser particle size analyzer, and D90 ≤ 100 nm.

[0048] Epoxy resin cross-linking reaction control (step t3): Preheat the epoxy resin at 120 - 130 °C to reduce its viscosity (from 2000 mPa·s to 800 mPa·s), facilitating its rapid incorporation into asphalt; a shear force of 3000 - 4000 r / min promotes the contact between epoxy groups and carboxylic acid groups of asphaltenes (the collision frequency increases by 2 times), and the degree of cross-linking reaction can reach over 70% (verified by detecting the residual amount of epoxy groups through Fourier transform infrared spectroscopy).

[0049] Secondary ultrasonic dispersion (step t4): The cavitation effect generated by 20 - 40 kHz ultrasonic waves breaks the incompletely dispersed epoxy resin microdroplets (from 5 μm to less than 1 μm), and promotes the transformation of nanocellulose from "aggregates - dispersions" to "single filaments - network structures", increasing the complex shear modulus (G*) of asphalt by 25%.

[0050] The beneficial effects of the present invention are as follows: (1) Through the innovative application of ionic liquid-assisted dispersion technology and bio-based epoxy resin, on the basis of the synergistic reinforcement of nanocellulose and epoxy resin in asphalt, the present invention breaks through the dispersion problems and performance bottlenecks of the existing technology, and for the first time systematically applies it to asphalt modification, achieving a comprehensive improvement in performance, environmental friendliness, and practicality through multi-component synergy and process optimization; (2) By adopting component synergy, a triple synergy of nanocellulose hydrogen bond network + bio-based epoxy chemical cross-linking + ionic liquid interface optimization is formed to form an interpenetrating network structure. This synergy mechanism makes the viscosity (≥ 20000 mPa·s at 60 °C) and ductility (≥ 30 cm at 5 °C) of the present invention significantly superior to the existing technology. The softening point breaks through the 85 °C bottleneck of traditional high-viscosity asphalt, meeting the requirements for rutting resistance of road surfaces in extremely high-temperature regions (such as Xinjiang, the Middle East). When the measured viscosity at 60 °C is 22000 mPa·s, the softening point reaches 92 - 95 °C. The flexible network of nanocellulose and the cross-linked structure of epoxy resin synergistically resist low-temperature cracking, and there are no cracks in the -10 °C bending test, which is better than the requirements of JT / T 860.1 - 2013 standard, and the ductility ≥ 20 cm; (3) The present invention uses cashew shell liquid to modify epoxy resin. The proportion of bio-based epoxy resin exceeds 30%, replacing traditional petroleum-based materials, which is in line with the "dual carbon" goal. The utilization of cashew shell liquid realizes the high-value conversion of agricultural waste. The high proportion of bio-based components significantly reduces the dependence on petroleum resources, conforming to the trend of green development. (4) The present invention uses cashew shell liquid to modify epoxy resin to achieve a dual optimization of "quality and quantity" of asphalt viscosity through a chain reaction of chemical structure adaptability → improvement of interfacial compatibility → construction of a cross-phase network. The improvement in "quantity" directly increases the molecular motion resistance through chemical cross-linking and physical entanglement, making the viscosity reach an ultra-high viscosity level (≥20000 mPa·s at 60 °C). The optimization of "quality" maintains excellent toughness and stability at high viscosity, solving the defect of "sticky and brittle" of traditional high-viscosity asphalt. (5) Compared with traditional SBS modified asphalt that requires high-temperature shearing at 180 - 200 °C, the highest temperature of this process is controlled at 180 °C, and the ultrasonic treatment time is only 15 minutes, reducing energy consumption by 20% and having no solvent emissions (xylene is only used as a dispersion aid in step t2 and naturally volatilizes during subsequent cooling, with a residual amount ≤0.01%), which complies with the EU REACH regulation.

[0051] In summary, the present invention has the advantages of high viscosity of the modified asphalt, being green and environmentally friendly, with the asphalt viscosity, softening point, and low-temperature ductility being significantly superior to traditional modified asphalt, and having better aging performance. It is particularly suitable for the technical field of modified high-viscosity asphalt. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a physical diagram of the modified asphalt in Example 1 of the present invention. Figure 2 It is a curve graph of the dynamic thermomechanical analysis data of the modified asphalt in Example 1 of the present invention. Figure 3 It is a schematic flow chart of the preparation method of the cashew shell liquid-modified epoxy resin in Example 1 of the present invention. Figure 4 It is a flow chart of the preparation of the modified asphalt in Example 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0053] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0054] The specific embodiments of the present invention will be described in detail below. It should be noted, however, that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the appended claims.

[0055] All publications, patent applications, patents, and other references mentioned in this specification are hereby incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0056] When this specification uses prefixes such as "well-known to those skilled in the art", "prior art", or their similar terms to introduce materials, substances, methods, steps, devices, or components, etc., the objects introduced by such prefixes cover those commonly used in the art at the time when the present invention is proposed, but also include those that are not commonly used at present but will become recognized in the art as suitable for similar purposes.

[0057] It should be specifically noted that two or more aspects (or embodiments) disclosed in the context of this specification can be combined with each other arbitrarily, and the technical solutions (such as methods or systems) thus formed belong to a part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0058] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless it is not in line with the common understanding of those skilled in the art when based on weight.

[0059] Example 1: As Figure 1 shown, an energy-saving, environmentally friendly, durable, and highly viscous modified asphalt includes the following components by mass parts: 100 parts of matrix asphalt, 0.8 - 1.2 parts of nanocellulose, 4 - 6 parts of bio-based epoxy resin, 0.3 - 0.5 parts of ionic liquid, 0.5 - 0.8 parts of hindered phenol antioxidant, and 1 - 2 parts of compatibilizer.

[0060] Among them, the matrix asphalt includes one or more selected from 50#, 70#, 90#, or 110# road petroleum asphalt.

[0061] And when multiple matrix asphalts are compounded, the mass ratio of each asphalt component is (50 - 100) : (0 - 50), and the penetration coefficient of variation of the compounded asphalt ≤ 5%.

[0062] Furthermore, the four-component composition of the matrix asphalt needs to satisfy saturates 20 - 35%, aromatics 30 - 45%, resins 20 - 30%, and asphaltenes 5 - 15%.

[0063] In addition, the penetration of the base asphalt is 50 - 110; the softening point ≥ 46°C, the ductility ≥ 100 cm, the flash point ≥ 260°C, and the wax content ≤ 2.2%.

[0064] In the present invention, the nanofibrillated cellulose is preferably nanofibrillated cellulose, and the specific surface area of the nanofibrillated cellulose ≥ 100 m² / g, the nanoscale diameter is 5 - 50 nm, the aspect ratio ≥ 20, and the crystallinity ≥ 50%.

[0065] It should be noted here that in the present technical solution, nanofibrillated cellulose (NFC) is preferably used as the reinforcing phase, mainly based on the precise matching of its unique structural characteristics with the requirements of asphalt modification, and it has significant technical advantages compared with other types of nanofibrillated cellulose (such as CNC, BC). The specific utilization is as follows: 1. The aspect ratio of NFC (≥ 20) enables it to form a continuous three-dimensional network structure in asphalt. When the asphalt is subjected to external forces, the network can effectively transfer stress and inhibit the propagation of microcracks. Dynamic shear rheological tests (DSR) show that the complex shear modulus (G*) of the asphalt with 1.0 part of NFC added increases by 60% compared with the unmodified asphalt, while that of CNC with the same content only increases by 35%; 2. The crystalline region of NFC (50 - 70%) provides rigid support, and the non-crystalline region forms a hydrogen bond network through hydroxyl groups. This "rigid-flexible combination" structure enables it to maintain viscosity (≥ 20000 mPa·s) at high temperatures (60°C), and still has good ductility (ductility ≥ 30 cm) at low temperatures (-10°C). Due to the high crystallinity (70 - 90%) of CNC, its brittleness increases, and the low-temperature ductility is only 15 - 20 cm; 3. Surface hydroxyl regulation, the hydroxyl density of NFC (1.5 - 3.0 mmol / g) is moderate, which can not only form hydrogen bonds with polar components in asphalt, but also not be overly hydrophilic to cause agglomeration. After pretreatment with ionic liquid (BMIMPF6), the dispersion degree of NFC in asphalt can reach more than 95%, while CNC is prone to form irreversible aggregates due to its too high surface hydroxyl density (2.5 - 4.0 mmol / g); 4. Aspect ratio advantage, the flexible long fibers of NFC are more easily uniformly dispersed under high-speed shearing (5000 - 6000 r / min), while the short rod-like structure of CNC is prone to orientation arrangement during shearing, resulting in local stress concentration.

[0066] As Figure 2 shown, in addition, the hydrogen bond network of NFC interpenetrates with the chemical cross-linking network of epoxy resin to form a "double continuous phase" structure. Dynamic thermomechanical analysis (DMA) shows that this structure raises the viscoelastic transition temperature (Tg) of the asphalt from -15°C to -8°C, and the high-temperature storage modulus (G') is increased by 2 times.

[0067] Preferably, the bio-based epoxy resin is a cashew shell liquid modified epoxy resin, the epoxy value of the cashew shell liquid modified epoxy resin is 0.2 - 0.4 mol / 100g, the viscosity is 500 - 2000 mPa·s, and the hydroxyl content is 1.5 - 3.0 mmol / g.

[0068] As Figure 3 shown, wherein the modification method of the cashew shell liquid modified epoxy resin includes the following steps: Step a1, pretreatment of cashew shell liquid: The cashew shell liquid is vacuum dried at 60 - 80°C for 2 - 3 hours to remove moisture and low-boiling impurities. Step a2, prepolymerization reaction: Charge the cashew shell liquid and bisphenol A epoxy resin in a mass ratio of 1:(2 - 3), add 0.5 - 1.0% of p-toluenesulfonic acid catalyst based on the total mass, heat up to 120 - 140°C, and stir and react for 2 - 3 hours under nitrogen protection to obtain a cashew shell liquid grafted epoxy resin intermediate. Step a3, epoxy group adjustment: Add epichlorohydrin to the intermediate, the mass of epichlorohydrin accounts for 5 - 10% of the mass of the intermediate, and carry out epoxidation reaction at 50 - 60°C for 1 - 2 hours under the catalysis of 10 - 15% NaOH aqueous solution to adjust the epoxy value to 0.2 - 0.4 mol / 100g. Step a4, solvent removal: The reaction product in step a3 is distilled at 100 - 120°C and a vacuum degree ≤10 kPa for 30 - 60 min to remove the residual solvent, and the target modified epoxy resin is obtained.

[0069] Preferably, the ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate, the surface tension is 40 - 50 mN / m, and the viscosity at room temperature is 300 - 500 mPa·s; The hindered phenol antioxidant is antioxidant 1010; The compatibilizer is maleic anhydride grafted polyethylene, the maleic anhydride grafting rate is 1.0% - 2.5%, and the melt flow rate is 1 - 5 g / 10 min.

[0070] Example 2: As Figure 4 shown, a process for preparing the energy-saving, environmentally friendly, durable and highly viscous modified asphalt described in Example 1 includes the following steps: Step t1, pretreatment of matrix asphalt: Heat the matrix asphalt to 160 - 170°C, add the ionic liquid, and stir at 800 - 1000 r / min for 15 min to promote the uniform dispersion of the ionic liquid. Step t2: Dispersion of nanocellulose. Mix nanocellulose with a compatibilizer, add an appropriate amount of xylene, and ultrasonically disperse for 30 min at a power of 200 - 300 W to form a stable suspension. Add the suspension to the pretreated asphalt, heat it to 170 - 180 °C, and perform high-speed shearing at 5000 - 6000 r / min for 30 min to evenly distribute the nanocellulose. Step t3: Blending of bio-based epoxy resin. Heat the bio-based epoxy resin to 120 - 130 °C, slowly add it to the asphalt system, maintain the temperature at 170 - 180 °C, and shear at 3000 - 4000 r / min for 20 min to promote the cross-linking reaction. Step t4: Addition of antioxidant and ultrasonic treatment. Add a hindered phenolic antioxidant and continue stirring for 10 min. Use an ultrasonic processor to perform secondary dispersion on the asphalt at a power of 300 - 400 W, a frequency of 20 - 40 kHz, and a treatment time of 15 min to further refine the microstructure. Step t5: Cooling and testing. Naturally cool to room temperature and test the softening point, Brookfield viscosity, and ductility at 5 °C to ensure that the performance meets the standards.

[0071] Among them, the addition amount of xylene is 5 - 8 times (mass ratio) of the total mass of nanocellulose and the compatibilizer, that is: the dosage of xylene (parts) = (the mass of nanocellulose + the mass of the compatibilizer) × (5 - 8).

[0072] The quantification basis is as follows: Nanocellulose (NFC) has a high specific surface area (≥100 m² / g) and strong hydrogen bond interactions, and is prone to agglomeration; the compatibilizer (maleic anhydride grafted polyethylene) is a polymer and requires solvent-assisted dispersion. As a polar organic solvent, xylene can effectively wet the surface of nanocellulose, reduce its surface energy, and dissolve the compatibilizer at the same time to form a uniform dispersion medium. Research shows that when the mass ratio of the solvent to the solid is 5:1 - 10:1, ultrasonic dispersion can form a stable suspension (without obvious precipitation), and avoid excessive solvent resulting in too many foams during subsequent high-temperature shearing.

[0073] In step t2, after dispersion, the suspension needs to be added to the matrix asphalt at 170 - 180 °C. The boiling point of xylene is 138 - 144 °C, and it can volatilize quickly at high temperatures, with a very low residual amount (≤0.1%), meeting the requirements of energy conservation and environmental protection. If the solvent dosage is insufficient (<5 times), nanocellulose and the compatibilizer are prone to caking, and there are still aggregates after ultrasonic dispersion, resulting in "fish eye" defects in the asphalt system; if the dosage is too much (>8 times), although the dispersion effect is improved, it increases the energy consumption of solvent volatilization and may affect the basic performance of the asphalt.

[0074] Preparation Example 1: Raw material composition (weight parts): 100 parts (70# road petroleum asphalt, single matrix asphalt, penetration 68, softening point 48 °C, ductility 120 cm, flash point 270 °C, wax content 2.0%, four-component composition: saturates 25%, aromatics 40%, resins 22%, asphaltenes 13%); Nanocellulose: 1 part (nanofibrillated cellulose, specific surface area 120 m² / g, diameter 20 nm, aspect ratio 25, crystallinity 55%); Bio-based epoxy resin: 5 parts (cardanol-modified epoxy resin, epoxy value 0.3 mol / 100 g, viscosity 500 mPa·s, hydroxyl content 1.5 mmol / g); Ionic liquid: 0.4 part (1-butyl-3-methylimidazolium hexafluorophosphate, surface tension 45 mN / m, viscosity 350 mPa·s); Hindered phenol antioxidant: 0.6 part (antioxidant 1010); Compatibilizer: 1.5 parts (maleic anhydride grafted polyethylene, grafting rate 1.0%, melt flow rate 1 g / 10 min); Xylene: 15 parts; The preparation steps refer to Example 2, the pretreatment temperature of the matrix asphalt is 160 °C, the ultrasonic power during the dispersion of nanocellulose is 200 W, the bio-based epoxy resin is heated to 120 °C, the ultrasonic treatment power is 300 W, and the frequency is 20 kHz.

[0075] Preparation Example 2: Raw material composition (parts by weight): Matrix asphalt: 100 parts (compound of 50# and 90# road petroleum asphalt, mass ratio 50:50, penetration coefficient of variation 4.5%, penetration 65, softening point 47 °C, ductility 110 cm, flash point 265 °C, wax content 2.1%, four-component composition: saturates 22%, aromatics 42%, resins 23%, asphaltenes 13%); Nanocellulose: 0.8 part (nanofibrillated cellulose, specific surface area 100 m² / g, diameter 5 nm, aspect ratio 30, crystallinity 60%); Bio-based epoxy resin: 6 parts (epoxy value 0.2 mol / 100 g); Ionic liquid: 0.3 part (same as Example 1, surface tension 40 mN / m); Hindered phenol antioxidant: 0.5 part (same as Example 1); Compatibilizer: 1 part (same as Example 1); Xylene: 13 parts; The preparation steps refer to Example 2, the pretreatment temperature of the matrix asphalt is 165 °C, the ultrasonic power during the dispersion of nanocellulose is 250 W, the high-speed shear rate is 5500 r / min, and the bio-based epoxy resin is heated to 125 °C.

[0076] Preparation Example 3: Raw material composition (parts by weight): Matrix asphalt: 100 parts (a blend of No. 50 and No. 90 road petroleum asphalt with a mass ratio of 70:30, penetration coefficient of 3.8%, penetration of 80, softening point of 46 °C, ductility of 105 cm, flash point of 260 °C, wax content of 2.2%, four-component composition: saturates 30%, aromatics 35%, resins 25%, asphaltenes 10%); Nanocellulose: 1.2 parts (nanofibrillated cellulose, specific surface area of 150 m² / g, diameter of 50 nm, aspect ratio of 40, crystallinity of 58%); Bio-based epoxy resin: 4 parts (cardanol-modified epoxy resin, epoxy value of 0.4 mol / 100 g, viscosity of 2000 mPa·s, hydroxyl content of 3.0 mmol / g); Ionic liquid: 0.5 parts (surface tension of 50 mN / m, viscosity of 400 mPa·s); Hindered phenol antioxidant: 0.8 parts; Compatibilizer: 2 parts (maleic anhydride grafting rate of 2.5%, melt flow rate of 5 g / 10 min); Xylene: 22 parts; The preparation steps refer to Example 2, with the pretreatment temperature of the matrix asphalt being 170 °C, the ultrasonic power during the dispersion of nanocellulose being 300 W, the bio-based epoxy resin being heated to 130 °C, and the ultrasonic treatment power being 400 W and the frequency being 40 kHz.

[0077] Preparation Example 4: Raw material composition (parts by weight): Matrix asphalt: 100 parts (No. 110 road petroleum asphalt, single matrix asphalt, penetration of 90, softening point of 49 °C, ductility of 150 cm, flash point of 280 °C, wax content of 1.8%, four-component composition: saturates 28%, aromatics 38%, resins 21%, asphaltenes 13%); Nanocellulose: 1.0 part (same as Example 3); Bio-based epoxy resin: 5 parts (epoxy value of 0.3 mol / 100 g, viscosity of 1000 mPa·s, hydroxyl content of 2.0 mmol / g); Ionic liquid: 0.4 parts (surface tension of 50 mN / m, viscosity of 500 mPa·s); Hindered phenol antioxidant: 0.6 part (same as Example 3); Compatibilizer: 1.5 parts (same as Example 3); Xylene: 17 parts; The preparation steps refer to Example 2. When dispersing nanocellulose, the high-speed shearing rate is 6000 r / min, the shearing rate of the bio-based epoxy resin is 4000 r / min, and the ultrasonic treatment time is 15 min.

[0078] Preparation Example 5: Raw material composition (parts by weight): Matrix asphalt: 100 parts (70# road petroleum asphalt, single matrix asphalt, penetration 110, softening point 46 °C, ductility 200 cm, flash point 260 °C, wax content 2.2%, four-component composition: saturates 35%, aromatics 30%, resins 20%, asphaltenes 15%); Nanocellulose: 0.8 parts (nanofibrillated cellulose, specific surface area 100 m² / g); Bio-based epoxy resin: 4 parts (epoxy value 0.2 mol / 100 g); Ionic liquid: 0.3 parts (surface tension 40 mN / m); Hindered phenol antioxidant: 0.5 parts; Compatibilizer: 1 part (maleic anhydride grafting rate 1%); Xylene: 9 parts; The preparation steps refer to Example 2. The pretreatment temperature of the matrix asphalt is 170 °C, the ultrasonic power is 300 W when dispersing nanocellulose, the bio-based epoxy resin is heated to 130 °C, the ultrasonic treatment power is 400 W, and the frequency is 40 kHz.

[0079] Comparative Example 1: The raw material composition is the same as that of Preparation Example 5, except that NFC is not used and the epoxy resin is not modified and is a common bisphenol A epoxy resin.

[0080] Comparative Example 2: The raw material composition is the same as that of Preparation Example 5, except that the epoxy resin is not modified and is a common bisphenol A epoxy resin.

[0081] Comparative Example 3: The raw material composition is the same as that of Preparation Example 5, except that ionic liquid-assisted dispersion is not used.

[0082] Comparative Example 4: The raw material composition is the same as that of Preparation Example 5, except that the nanocellulose is CNC instead of NFC.

[0083] Comparative Example 5: Original 70# road petroleum asphalt.

[0084] Test Example 1: For Preparation Examples 1-5 and Comparative Examples 1-5, the softening point was tested with reference to GB / T 4507-2014 "Determination of Softening Point of Bitumen (Ring and Ball Method)", the viscosity was tested with reference to GB / T 19952-2018 "Test Method for Brookfield Rotational Viscosity of Bitumen", and the rutting resistance factor was tested with reference to JT / T 740-2015 "Test Procedure for Dynamic Shear Rheology of Asphalt Mixtures". The test results are shown in Table 1 below: Table 1 From the comparison between Preparation Examples 1-5 and Comparative Examples 1-5, it can be seen that in Comparative Example 1: the lack of NFC led to insufficient physical enhancement, and the performance was close to that of traditional SBS modified bitumen (but still lower than that of the preparation examples).

[0085] In Comparative Example 2: the compatibility of ordinary epoxy resin was poor, the cross-linking efficiency was low, and the softening point and viscosity decreased significantly.

[0086] In Comparative Example 3: when there was no ionic liquid, the nanocellulose agglomerated, and the dispersion degree decreased from 95% to 70%, resulting in a significant attenuation of performance.

[0087] In Comparative Example 4: the rigid structure and low aspect ratio of CNC led to a weak enhancement effect, verifying the necessity of the selection of NFC.

[0088] In summary, all the preparation examples met the requirements of softening point ≥ 88 °C, viscosity ≥ 20000 mPa·s, and rutting resistance factor ≥ 4.8 kPa, which were significantly better than the original bitumen and the comparative examples. Although the performance of the worst preparation example (Comparative Example 5) was close to the lower limit, it still met the requirements of the claims, proving the rationality of the formula range. The compound bitumen (Preparation Example 3) and low-temperature adaptation (Preparation Example 4) demonstrated the wide applicability of the scheme.

[0089] 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 in the protection scope of the present invention.

Claims

1. An energy-saving, environmental-friendly, durable and highly viscous modified asphalt, characterized in that, Comprising the following components by mass parts: 100 parts of matrix asphalt, 0.8 - 1.2 parts of nanocellulose, 4 - 6 parts of bio-based epoxy resin, 0.3 - 0.5 parts of ionic liquid, 0.5 - 0.8 parts of hindered phenol antioxidant, and 1 - 2 parts of compatibilizer.

2. The energy-saving, environment-friendly, durable and highly viscous modified asphalt according to claim 1, characterized in that: The matrix asphalt includes one or more selected from No. 50, No. 70, No. 90 or No. 110 road petroleum asphalt.

3. The energy-saving, environment-friendly, durable and highly viscous modified asphalt according to claim 2, characterized in that: When multiple matrix asphalts are compounded, the mass ratio of each asphalt component is (50 - 100):(0 - 50), and the penetration coefficient of the compounded asphalt ≤ 5%.

4. The energy-saving, environment-friendly, durable and highly viscous modified asphalt according to claim 2 or 3, characterized in that: The four-component composition of the matrix asphalt needs to satisfy saturates 20 - 35%, aromatics 30 - 45%, resins 20 - 30%, and asphaltenes 5 - 15%.

5. The energy-saving, environment-friendly, durable and highly viscous modified asphalt according to claim 2 or 3, characterized in that: The penetration of the matrix asphalt is 50 - 110; softening point ≥ 46 °C, ductility ≥ 100 cm, flash point ≥ 260 °C, and wax content ≤ 2.2%.

6. The energy-saving, environment-friendly, durable and highly viscous modified asphalt according to claim 1, characterized in that: The nanocellulose is nanofibrillated cellulose, and the specific surface area of the nanofibrillated cellulose ≥ 100 m² / g, nanoscale diameter 5 - 50 nm, aspect ratio ≥ 20, and crystallinity ≥ 50%.

7. The energy-saving, environment-friendly, durable and highly viscous modified asphalt according to claim 1, characterized in that: The bio-based epoxy resin is cashew shell liquid modified epoxy resin, and the epoxy value of the cashew shell liquid modified epoxy resin is 0.2 - 0.4 mol / 100 g, viscosity is 500 - 2000 mPa·s, and hydroxyl content is 1.5 - 3.0 mmol / g.

8. The energy-saving, environmental-protection, durable and highly viscous modified asphalt according to claim 7, wherein The modification method of the cashew shell liquid modified epoxy resin includes the following steps: Step a1, pretreatment of cashew shell liquid, vacuum-drying the cashew shell liquid at 60 - 80 °C for 2 - 3 hours to remove moisture and low-boiling impurities; Step a2, prepolymerization reaction, charging according to the mass ratio of cashew shell liquid to bisphenol A epoxy resin of 1:(2 - 3), adding 0.5 - 1.0% of p-toluenesulfonic acid catalyst based on the total mass, heating to 120 - 140 °C, and stirring and reacting for 2 - 3 hours under nitrogen protection to obtain a cashew shell liquid grafted epoxy resin intermediate; Step a3, epoxy group adjustment, adding epichlorohydrin to the intermediate, the mass of epichlorohydrin accounts for 5 - 10% of the mass of the intermediate, and carrying out epoxidation reaction at 50 - 60 °C for 1 - 2 hours under the catalysis of 10 - 15% NaOH aqueous solution to adjust the epoxy value to 0.2 - 0.4 mol / 100 g; Step a4, solvent removal, distilling the reaction product in step a3 at 100 - 120 °C and vacuum degree ≤ 10 kPa for 30 - 60 min to remove residual solvent and obtain the target modified epoxy resin.

9. The energy-saving, environment-friendly, durable and highly viscous modified asphalt according to claim 1, characterized in that: The ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate, with a surface tension of 40-50 mN / m and a viscosity of 300-500 mPa·s at room temperature; The hindered phenol antioxidant is antioxidant 1010; The compatibilizer is maleic anhydride grafted polyethylene, with a maleic anhydride grafting rate of 1.0%-2.5% and a melt flow rate of 1-5 g / 10 min.

10. A process for preparing the energy-saving, environment-friendly, durable and highly viscous modified asphalt according to any one of claims 1-9, characterized in that, It includes the following steps: Step t1, pretreatment of the base asphalt: heat the base asphalt to 160-170 °C, add the ionic liquid, and stir at 800-1000 r / min for 15 min to promote the uniform dispersion of the ionic liquid; Step t2, dispersion of nanocellulose: mix the nanocellulose with the compatibilizer, add an appropriate amount of xylene and ultrasonically disperse for 30 min at a power of 200-300 W to form a stable suspension. Add the suspension to the pretreated asphalt, heat up to 170-180 °C, and perform high-speed shearing at 5000-6000 r / min for 30 min to make the nanocellulose evenly distributed; Step t3, blending of bio-based epoxy resin: heat the bio-based epoxy resin to 120-130 °C, slowly add it to the asphalt system, keep the temperature at 170-180 °C, and shear at 3000-4000 r / min for 20 min to promote the cross-linking reaction; Step t4, addition of antioxidant and ultrasonic treatment: add the hindered phenol antioxidant, continue stirring for 10 min, and use an ultrasonic processor to perform secondary dispersion on the asphalt at a power of 300-400 W, a frequency of 20-40 kHz, and a treatment time of 15 min to further refine the microstructure; Step t5, cooling and testing: naturally cool to room temperature, and test the softening point, Brookfield viscosity, and ductility at 5 °C to ensure that the performance meets the standards.

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