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 asphalt material modification and preparation, and in particular to energy-saving, environmentally 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. It has good adhesion, water resistance 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 indicator that determines the quality of road paving. Improving the viscosity has the following promoting effects: 1. Reduce the shedding or loosening of aggregates and improve the integrity of the mixture.

[0004] 2. Improve high temperature stability and reduce rutting damage.

[0005] 3. Enhance low-temperature crack resistance and delay the occurrence of cracks.

[0006] 4. Improve resistance to water damage and reduce road damage.

[0007] The existing methods of adjusting the viscosity of asphalt are mostly modification treatments. For example, in the invention patent with patent application number 202410591394.6, a road-use anti-rutting asphalt mixture and its preparation method are specifically disclosed. The mixture comprises the following components in parts by weight: 10-20 parts of matrix asphalt, 70-90 parts of aggregate, 5-10 parts of nano-scale filler, 5-10 parts of amino-type nanocellulose 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 properties. Moreover, performance tests have shown that the addition of nano-montmorillonite, amino-type nanocellulose whiskers, polymer elastomer, and carboxyl-terminated liquid nitrile rubber plays a positive role in improving the performance of the asphalt mixture. Among them, the hydrogen bond network of the amino-type nanocellulose whiskers and the chemical crosslinking of the epoxy resin simultaneously improve the viscosity and toughness of the asphalt.

[0008] However, nanocellulose modified asphalt technology 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 of 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 response to the above problems, the present invention provides energy-saving, environmentally friendly, durable and highly viscous modified asphalt and its preparation process. By using ionic liquid to disperse nanocellulose and combining it with bio-based epoxy resin, the dispersion uniformity of nanocellulose in asphalt is improved, and the compatibility between epoxy resin and asphalt is enhanced, thereby further improving the viscosity of asphalt, and enhancing the asphalt's softening point, viscosity and anti-rutting factor and other properties.

[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 No. 50, No. 70, No. 90 or No. 110 road petroleum asphalt.

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

[0014] Preferably, the four-component composition of the matrix asphalt should meet the requirements of 20-35% saturates, 30-45% aromatics, 20-30% colloids, and 5-15% asphaltenes.

[0015] The saturated and aromatic components, as low-molecular-weight components of asphalt, provide a dispersion medium for nanocellulose and epoxy resin. The colloid (20-30%) acts as a peptizing carrier, adsorbing asphaltene (5-15%) via polar groups to form a stable colloidal structure. If the asphaltene content is too high (>15%), nanocellulose can easily agglomerate; if it is too low (<5%), there will be insufficient crosslinking sites.

[0016] Preferably, the base asphalt has a needle penetration of 50-110 (25°C, 100g, 5s, 0.1mm); a softening point ≥46°C (ring and ball method), an elongation ≥100cm (15°C, 5cm / min), a flash point ≥260°C (COC), and a wax content ≤2.2% (distillation method).

[0017] The base asphalt has a penetration range of 50-110 to meet the needs of different climate zones. During compounding, the coefficient of variation of the penetration is controlled to ≤5% to ensure a uniform molecular weight distribution of the mixed asphalt and avoid segregation of the modifier between high and low molecular weight components. For example, a 7:3 ratio of No. 70 and No. 90 asphalts can achieve a balanced balance of high-temperature viscosity and low-temperature toughness.

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

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

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

[0021] Crystallinity ≥50%: The rigid chain segments in the crystalline region inhibit molecular chain slippage, and the hydroxyl groups in the non-crystalline region promote hydrogen bonding with the epoxy resin, achieving a "rigid and flexible" reinforcement effect.

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

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

[0024] Existing technologies for modifying asphalt with bio-based epoxy resins (such as the invention patent with application number CN117487369A) primarily use curing agents such as pentamethylenediamine and do not involve cashew nut shell liquid-modified epoxy resins. Cashew nut shell liquid-modified epoxy resins, however, have a natural phenolic structure that not only enhances compatibility with asphalt but also enables high-value utilization of agricultural waste.

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

[0026] The phenolic hydroxyl groups in its molecules can form hydrogen bonds with the carbonyl groups (C=O) and hydroxyl groups (—OH) of 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 saturated components and aromatic components) through van der Waals forces, forming a dual adaptive 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 modified epoxy resin and asphalt is approximately 12-15 mN / m, while that of modified cashew nut shell liquid is reduced to 5-8 mN / m (calculated using the Owens-Wendt equation). This low interfacial tension promotes molecular diffusion of the epoxy resin in the asphalt, shifting the compatibility between the modifier and asphalt from "phase separation" to "semi-miscible." Microstructural observations show that the dispersed phase size decreases from 5-10 μm to 1-2 μm, with no apparent interfacial boundary.

[0028] The epoxy groups (—O—) in the cashew nut shell liquid modified epoxy resin can undergo a ring-opening addition reaction with the acidic groups (such as carboxylic acids and phenols) in the asphaltene under the hot oxygen environment of asphalt to form a covalent bond (the reaction formula is as follows): R-COOH+CH2-CH-O-→R-COO-CH2-CH-OH This chemical crosslinking creates a three-dimensional network in the asphalt, significantly increasing the resistance to molecular chain motion. Compared to unmodified epoxy resin, the modified asphalt's viscosity at 60°C increases from 12,000 mPa·s to 22,000 mPa·s, and its viscosity-temperature sensitivity (viscosity-temperature index) decreases by 35%, indicating enhanced viscosity retention at high temperatures.

[0029] Furthermore, the synergistic viscosity enhancement of physical entanglement and hydrogen bond network, the molecular entanglement of long carbon chains, and the C15 long chains of cashew nut shell liquid form "molecular bridges" in asphalt, entangled with the high molecular weight components of asphalt (such as asphaltenes), increasing the internal friction resistance; The expansion of the hydrogen bond network, the phenolic hydroxyl group and the hydroxyl group (-OH) of nanocellulose and the polar group of asphalt form a cross-phase hydrogen bond network, so that a "physical anchor point" is formed between the modifier, asphalt and nanocellulose, further restricting the movement of the molecular chain; This physical-chemical synergistic effect enables the asphalt to maintain an ductility of ≥30cm at 5°C (traditional high-viscosity asphalt is only 15-20cm), that is, it maintains excellent toughness under high viscosity, breaking the traditional contradiction of "viscosity-toughness".

[0030] Furthermore, the natural antioxidant groups in cashew nut shell liquid (such as catechol structures) work synergistically with the hindered phenolic antioxidant (Irganox 1010) to stabilize viscosity during aging. This inhibits the volatilization of light components and molecular chain breakage caused by asphalt oxidation. After accelerated aging testing (RTFOT+PAV), the asphalt of this invention maintained a 60°C viscosity of ≥85%, compared to only 60-70% for conventional SBS-modified asphalt, demonstrating significantly slower viscosity degradation over long-term use.

[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, the maleic anhydride grafting rate is 1.0%-2.5%, and the melt flow rate is 1-5 g / 10 min (MFR, 190° C. / 2.16 kg).

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

[0033] Electrostatic stabilization effect: The positively charged imidazolium cations and the negatively charged cellulose hydroxyl groups form a double layer (zeta potential ≥ +25mV), which inhibits the agglomeration of nanofibers and makes the sedimentation rate of the dispersion less than 5% after standing for 72 hours (the sedimentation rate of the traditional dispersion method is >30%).

[0034] Hindered phenol antioxidant 1010 captures the alkyl radicals (ROO·) produced by asphalt oxidation, extending the induction period to 60 minutes (conventional asphalt only 30 minutes); the imidazolium cation of the ionic liquid forms a π-π conjugation with the nitrogen heterocycle of the asphaltene, inhibiting asphaltene coagulation during the oxidation process. The viscosity growth rate after aging is ≤15% (conventional modified asphalt ≥30%).

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

[0036] Chemical cross-linking: Cashew nut shell liquid modified epoxy resin reacts chemically with the polar components in asphalt to form a three-dimensional network structure (anti-rutting factor ≥ 5.0kPa, 66% higher than traditional SBS modified asphalt).

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

[0038] This synergistic mechanism makes the viscosity (60°C ≥ 20,000 mPa·s) and ductility (5°C ≥ 30 cm) of the present invention significantly better than the existing technology. The synergistic effect of nanocellulose and epoxy resin in existing patents (such as CN118344057B) is only manifested as a single performance improvement (such as a softening point of approximately 80°C).

[0039] The core innovation of this modification technology lies in utilizing the self-compatibilization properties of natural phenolic structures to achieve high-performance modification without the need for additional compatibilizers.

[0040] Preferably, the modification method of the cashew nut shell liquid modified epoxy resin comprises the following steps: Step a1, pretreatment of cashew nut shell liquid, vacuum drying the cashew nut shell liquid at 60-80° C. for 2-3 hours to remove moisture and low-boiling impurities; Step a2, prepolymerization reaction, adding cashew nut shell liquid and bisphenol A type epoxy resin in a mass ratio of 1: (2-3), adding 0.5-1.0% of p-toluenesulfonic acid catalyst based on the total mass, heating to 120-140° C., stirring and reacting under nitrogen protection for 2-3 hours to obtain a cashew nut shell liquid grafted epoxy resin intermediate; Step a3, epoxy group adjustment, epichlorohydrin is added to the intermediate, the mass of epichlorohydrin accounts for 5-10% of the mass of the intermediate, and the epoxidation reaction is carried out at 50-60° C. for 1-2 hours under the catalysis of a 10-15% NaOH aqueous solution 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 vacuum ≤10 kPa for 30-60 min to remove residual solvent and obtain the target modified epoxy resin.

[0041] The innovative features of cashew nut shell liquid modification process are as follows: 1. Pre-treatment and impurity removal (vacuum drying at 60-80°C) to remove moisture (≤0.5%) and low-boiling point fatty acids from cashew nut shell liquid to avoid the production of by-products (such as esters) in subsequent reactions and ensure the purity of the epoxy group.

[0042] 2. Graft 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, and a C15 long carbon chain is introduced into the epoxy resin backbone (reaction conversion rate ≥90%), so that the solubility parameter of the modified epoxy resin and the asphalt matching degree are increased from 0.82 to 0.95 (Hansen solubility parameter method).

[0043] 3. The epoxy value is precisely controlled (0.2-0.4 mol / 100g). Through secondary epoxidation with epichlorohydrin, the epoxy groups consumed in the grafting reaction are replenished to ensure that every 100g of resin contains 20-40mmol of active epoxy groups, forming a stoichiometric match with the carboxylic acid groups of asphaltene (about 15-25mmol / 100g asphalt) to maximize the cross-linking density.

[0044] In addition, the present invention also provides a process for preparing any of the above-mentioned energy-saving, environmentally friendly, durable and highly viscous modified asphalt, comprising the following steps: Step t1: pretreatment of the matrix asphalt: heating the matrix asphalt to 160-170° C., adding the ionic liquid, and stirring at 800-1000 rpm for 15 minutes to promote uniform dispersion of the ionic liquid; Step t2: Dispersing the nanocellulose: Mix the nanocellulose with a compatibilizer, add an appropriate amount of xylene, and ultrasonically disperse for 30 minutes at a power of 200-300W to form a stable suspension. Add the suspension to the pretreated asphalt, heat it to 170-180°C, and shear it at a high speed of 5000-6000 r / min for 30 minutes to evenly distribute the nanocellulose. Step t3: Blending the bio-based epoxy resin: heating the bio-based epoxy resin to 120-130° C., slowly adding it to the asphalt system, maintaining the temperature at 170-180° C., and shearing at 3000-4000 r / min for 20 minutes to promote the cross-linking reaction; Step t4, antioxidant addition and ultrasonic treatment: add a hindered phenol antioxidant, continue stirring for 10 minutes, and use an ultrasonic processor to perform secondary dispersion of the asphalt at a power of 300-400W, a frequency of 20-40kHz, and a treatment time of 15 minutes to further refine the microstructure; Step t5: Cooling and testing: Cool naturally to room temperature, 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): At 160-170°C, the ionic liquid melts and penetrates the asphaltene micelles, reducing the average asphaltene particle size from 500nm to below 200nm, creating space for subsequent nanocellulose insertion. A stirring speed of 800-1000 rpm avoids shear overheating (temperature rise ≤ 5°C) and protects the ionic liquid structure from decomposition.

[0046] Nanocellulose-compatibilizer co-dispersion (step t2): Xylene acts as a "bridge solvent" to dissolve the compatibilizer (MAPE) and swell the surface of nanocellulose. Ultrasonic treatment (200-300W) allows the maleic anhydride groups of MAPE to form ester bonds with the cellulose hydroxyl groups (reaction degree ≥30%), thereby increasing 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 fibers. The dispersion uniformity is detected by a laser particle size analyzer, and D90 is ≤100 nm.

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

[0049] Ultrasonic secondary dispersion (step t4): The cavitation effect generated by 20-40kHz ultrasound breaks up incompletely dispersed epoxy resin droplets (from 5μm to below 1μm) and promotes the transformation of nanocellulose from "agglomerate-dispersion" to "single filament-network", increasing the complex shear modulus (G*) of asphalt by 25%.

[0050] The beneficial effects of the present invention are: (1) This invention, through the innovative application of ionic liquid-assisted dispersion technology and bio-based epoxy resin, breaks through the dispersion difficulties and performance bottlenecks of the existing technology on the basis of the synergistic reinforcement of asphalt by nanocellulose and epoxy resin. It is the first time that its system is applied to asphalt modification, and through multi-component synergy and process optimization, it achieves a comprehensive improvement in performance, environmental protection and practicality. (2) The present invention forms an interpenetrating network structure by adopting the triple synergy of component synergy, nanocellulose hydrogen bond network + bio-based epoxy chemical crosslinking + ionic liquid interface optimization. This synergistic mechanism makes the viscosity (60℃≥20000mPa·s) and ductility (5℃≥30cm) of the present invention significantly superior to the existing technology. The softening point breaks through the 85℃ bottleneck of traditional high-viscosity asphalt, meeting the rutting resistance requirements of road surfaces in extremely high temperature areas (such as Xinjiang and the Middle East). When the measured viscosity at 60℃ is 22000mPa·s, the softening point reaches 92-95℃. The flexible network of nanocellulose and the crosslinking structure of epoxy resin synergistically resist low-temperature cracking. There is no crack in the -10℃ bending test, which is better than the requirements of JT / T860.1-2013 standard, and the ductility is ≥20cm. (3) The present invention uses cashew nut shell liquid to modify epoxy resin, with bio-based epoxy resin accounting for more than 30%, replacing traditional petroleum-based materials, in line with the "dual carbon" goals. The utilization of cashew nut shell liquid realizes the high-value conversion of agricultural waste, and the high proportion of bio-based components significantly reduces dependence on petroleum resources, which is in line with the trend of green development; (4) The present invention uses cashew nut shell liquid modified epoxy resin to achieve a chain reaction of chemical structure adaptability → interface compatibility improvement → cross-phase network construction, thereby achieving a dual optimization of asphalt viscosity in terms of both quality and quantity. 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 (60°C ≥ 20,000 mPa·s). The optimization of "quality" maintains excellent toughness and stability at high viscosity, solving the defect of traditional high-viscosity asphalt being "sticky and brittle"; (5) Compared with the traditional SBS modified asphalt which requires high temperature shearing of 180-200℃, the maximum temperature of this process is controlled at 180℃, and the ultrasonic treatment time is only 15 minutes, which reduces energy consumption by 20%. There is no solvent emission (xylene is only used as a dispersing aid in step t2 and then naturally evaporates during the cooling process, with a residual amount of ≤0.01%), which complies with EU REACH regulations.

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

[0052] Figure 1 This is a physical picture of the modified asphalt of Example 1 of the present invention; Figure 2 This is a curve diagram of dynamic thermomechanical analysis data of modified asphalt in Example 1 of the present invention; Figure 3 This is a schematic diagram of the preparation process of the modification method of cashew nut shell liquid modified epoxy resin according to Example 1 of the present invention; Figure 4 This is a flow chart for preparing modified asphalt according to Example 2 of the present invention. DETAILED DESCRIPTION

[0053] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0054] The specific embodiments of the present invention are described in detail below. However, it should be noted that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims in the appendix.

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

[0056] When this specification uses the prefix "well known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, the objects introduced by the prefix include those conventionally used in the art when the present invention was proposed, but also include those that are not commonly used at present but will become generally recognized in the art to be suitable for similar purposes.

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

[0058] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless the weight basis does not conform to the general understanding of those skilled in the art.

[0059] Example 1: like Figure 1 As shown, an energy-saving, environmentally friendly, durable and highly viscous modified asphalt comprises 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.

[0060] Wherein, the matrix asphalt includes one or more selected from No. 50, No. 70, No. 90 or No. 110 road petroleum asphalt.

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

[0062] Furthermore, the four-component composition of the matrix asphalt must meet the requirements of 20-35% saturates, 30-45% aromatics, 20-30% colloids, and 5-15% asphaltenes.

[0063] In addition, the base asphalt has a needle penetration of 50-110, a softening point of ≥46°C, an elongation of ≥100cm, a flash point of ≥260°C, and a wax content of ≤2.2%.

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

[0065] It should be noted that in this technical solution, nanofibrillar cellulose (NFC) is preferred as the reinforcing phase, mainly due to its unique structural properties that precisely match the requirements of asphalt modification. Compared with other types of nanocellulose (such as CNC and BC), it has significant technical advantages. 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 transmit stress and inhibit the propagation of microcracks. Dynamic shear rheology tests (DSR) show that the complex shear modulus (G*) of asphalt with 1.0 part NFC increased by 60% compared to unmodified asphalt, while the same content of CNC only increased by 35%; 2. The crystalline region (50-70%) of NFC provides rigid support, while the amorphous region forms a hydrogen bond network through hydroxyl groups. This "rigid yet flexible" structure enables it to maintain viscosity (≥20,000 mPa·s) at high temperatures (60°C) while maintaining good ductility (≥30 cm) at low temperatures (-10°C). CNC, due to its high crystallinity (70-90%), increases brittleness, with a low-temperature ductility of only 15-20 cm. 3. Surface hydroxyl group regulation: NFC has a moderate hydroxyl group density (1.5-3.0 mmol / g), which allows it to form hydrogen bonds with polar components in asphalt without being overly hydrophilic and causing agglomeration. After pretreatment with ionic liquid (BMIMPF6), the dispersion of NFC in asphalt can reach over 95%. However, CNC is prone to forming irreversible agglomerates due to its high surface hydroxyl group density (2.5-4.0 mmol / g). 4. Advantage of aspect ratio: NFC's flexible long fibers are easier to disperse evenly under high-speed shearing (5000-6000r / min), while CNC's short rod-shaped structure is prone to orientation during the shearing process, resulting in local stress concentration.

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

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

[0068] like Figure 3 As shown, the modification method of the cashew nut shell liquid modified epoxy resin comprises the following steps: Step a1, pretreatment of cashew nut shell liquid, vacuum drying the cashew nut shell liquid at 60-80° C. for 2-3 hours to remove moisture and low-boiling impurities; Step a2, prepolymerization reaction, adding cashew nut shell liquid and bisphenol A type epoxy resin in a mass ratio of 1: (2-3), adding 0.5-1.0% of p-toluenesulfonic acid catalyst based on the total mass, heating to 120-140° C., stirring and reacting under nitrogen protection for 2-3 hours to obtain a cashew nut shell liquid grafted epoxy resin intermediate; Step a3, epoxy group adjustment, epichlorohydrin is added to the intermediate, the mass of epichlorohydrin accounts for 5-10% of the mass of the intermediate, and the epoxidation reaction is carried out at 50-60° C. for 1-2 hours under the catalysis of a 10-15% NaOH aqueous solution 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 vacuum ≤10 kPa for 30-60 min to remove residual solvent and obtain the target modified epoxy resin.

[0069] 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, the maleic anhydride grafting rate is 1.0%-2.5%, and the melt flow rate is 1-5g / 10min.

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

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

[0072] The quantification is based on the following: Nanocellulose (NFC) has a high specific surface area (≥100 m² / g) and strong hydrogen bonding, making it prone to agglomeration. The compatibilizer (maleic anhydride grafted polyethylene) is a high molecular weight polymer and requires a solvent to assist in dispersion. Xylene, as a polar organic solvent, effectively wets the nanocellulose surface, reducing its surface energy while dissolving the compatibilizer, forming a uniform dispersion medium. Research has shown that ultrasonic dispersion can form a stable suspension (without noticeable precipitation) when the solvent-to-solids mass ratio is between 5:1 and 10:1, while avoiding excessive solvent content that can lead to excessive foaming during subsequent high-temperature shearing.

[0073] In step t2, after dispersion, the suspension is added to the base asphalt at 170-180°C. Xylene, with a boiling point of 138-144°C, evaporates rapidly at high temperatures, leaving a very low residual amount (≤0.1%), meeting energy conservation and environmental protection requirements. If the solvent dosage is insufficient (less than 5 times), the nanocellulose and compatibilizer will easily agglomerate, and aggregates will remain after ultrasonic dispersion, resulting in "fish-eye" defects in the asphalt system. If the dosage is excessive (>8 times), while the dispersion effect is improved, the energy consumption for solvent evaporation increases, and the basic properties of the asphalt may be affected.

[0074] Preparation Example 1: Raw material composition (parts by weight): 100 parts (No. 70 road petroleum asphalt, single matrix asphalt, needle penetration 68, softening point 48°C, elongation 120cm, flash point 270°C, wax content 2.0%, four-component composition: saturates 25%, aromatics 40%, colloids 22%, asphaltenes 13%); Nanocellulose: 1 part (nanofibril cellulose, surface area 120 m² / g, diameter 20 nm, aspect ratio 25, crystallinity 55%); Bio-based epoxy resin: 5 parts (cashew nut shell liquid modified epoxy resin, epoxy value 0.3 mol / 100 g, viscosity 500 mPa·s, hydroxyl content 1.5 mmol / g); Ionic liquid: 0.4 parts (1-butyl-3-methylimidazolium hexafluorophosphate, surface tension 45 mN / m, viscosity 350 mPa·s); Hindered phenol antioxidant: 0.6 parts (antioxidant 1010); Compatibilizer: 1.5 parts (maleic anhydride grafted polyethylene, grafting rate 1.0%, melt flow rate 1g / 10min); Xylene: 15 parts; The preparation steps were similar to those in Example 2. The asphalt pretreatment temperature was 160° C., the ultrasonic power was 200 W during nanocellulose dispersion, the bio-based epoxy resin was heated to 120° C., the ultrasonic treatment power was 300 W, and the frequency was 20 kHz.

[0075] Preparation Example 2: Raw material composition (parts by weight): Base asphalt: 100 parts (compound of No. 50 and No. 90 road petroleum asphalt, mass ratio of 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%, colloids 23%, asphaltenes 13%); Nanocellulose: 0.8 parts (nanofibril cellulose, surface area 100 m² / g, diameter 5 nm, aspect ratio 30, crystallinity 60%); Bio-based epoxy resin: 6 parts (epoxy value 0.2 mol / 100g); Ionic liquid: 0.3 parts (same as in Example 1, surface tension 40 mN / m); Hindered phenol antioxidant: 0.5 parts (same as in Example 1); Compatibilizer: 1 part (same as Example 1); Xylene: 13 parts; The preparation steps refer to Example 2, the matrix asphalt pretreatment temperature is 165°C, the ultrasonic power is 250W during nanocellulose dispersion, the high-speed shear rate is 5500r / min, and the bio-based epoxy resin is heated to 125°C.

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

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

[0078] Preparation Example 5: Raw material composition (parts by weight): Base asphalt: 100 parts (No. 70 road petroleum asphalt, single base asphalt, needle penetration 110, softening point 46°C, elongation 200 cm, flash point 260°C, wax content 2.2%, four-component composition: saturates 35%, aromatics 30%, colloids 20%, asphaltenes 15%); Nanocellulose: 0.8 parts (nanofibril cellulose, specific surface area 100m² / g); Bio-based epoxy resin: 4 parts (epoxy value 0.2 mol / 100g); Ionic liquid: 0.3 parts (surface tension 40 mN / m); Hindered phenolic antioxidant: 0.5 parts; Compatibilizer: 1 part (maleic anhydride grafting rate 1%); Xylene: 9 parts; The preparation steps refer to Example 2, the matrix asphalt pretreatment temperature is 170°C, the ultrasonic power is 300W when the nanocellulose is dispersed, the bio-based epoxy resin is heated to 130°C, the ultrasonic treatment power is 400W, and the frequency is 40kHz.

[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 unmodified and is ordinary 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 ordinary bisphenol A epoxy resin.

[0081] Comparative Example 3: The raw material composition is the same as that of Preparation Example 5, except that no ionic liquid is used to assist dispersion.

[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 Route 70 petroleum asphalt.

[0084] Test Example 1: For Preparation Examples 1-5 and Comparative Examples 1-5, the softening point was tested in accordance with GB / T4507-2014 "Determination of Softening Point of Asphalt (Ring and Ball Method)", the viscosity was tested in accordance with "Test Procedure for Asphalt and Asphalt Mixtures for Highway Engineering" (JTG E20-2011), and the anti-rutting factor was tested. The test results are shown in Table 1 below: Table 1 By comparing Preparation Examples 1 to 5 with Comparative Examples 1 to 5, it can be seen that in Comparative Example 1: the lack of NFC leads to insufficient physical reinforcement, and the performance is close to that of traditional SBS modified asphalt (but still lower than that of the Preparation Example).

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

[0086] In Comparative Example 3, in the absence of ionic liquid, nanocellulose aggregated, the dispersion dropped from 95% to 70%, and the performance was greatly degraded.

[0087] In Comparative Example 4: The rigid structure and low aspect ratio of CNC lead to weak reinforcement effect, which verifies the necessity of NFC selection.

[0088] In summary, all preparation examples meet the requirements of softening point ≥88°C, viscosity ≥20,000 mPa·s, and anti-rutting factor ≥4.8 kPa, which are significantly better than the original asphalt and the comparative example. Although the performance of the worst preparation example (Comparative Example 5) is close to the lower limit, it still meets the claims, proving the rationality of the formula range. The compound asphalt (Preparation Example 3) and low-temperature adaptation (Preparation Example 4) demonstrate the wide applicability of the scheme.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An energy-saving, environmentally friendly, durable and highly viscous modified asphalt, characterized in that: It includes 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.

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

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

5. The energy-saving, environmentally friendly, durable and highly viscous modified asphalt according to claim 2 or 3, characterized in that: The base asphalt has a needle penetration of 50-110, a softening point of ≥46°C, an elongation of ≥100cm, a flash point of ≥260°C, and a wax content of ≤2.2%.

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

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

8. The energy-saving, environmentally friendly, durable and highly viscous modified asphalt according to claim 7, characterized in that: The modification method of the cashew nut shell liquid modified epoxy resin comprises the following steps: Step a1, pretreatment of cashew nut shell liquid, vacuum drying the cashew nut shell liquid at 60-80° C. for 2-3 hours to remove moisture and low-boiling impurities; Step a2, prepolymerization reaction, adding cashew nut shell liquid and bisphenol A type epoxy resin in a mass ratio of 1: (2-3), adding 0.5-1.0% of p-toluenesulfonic acid catalyst based on the total mass, heating to 120-140° C., stirring and reacting under nitrogen protection for 2-3 hours to obtain a cashew nut shell liquid grafted epoxy resin intermediate; Step a3, epoxy group adjustment, epichlorohydrin is added to the intermediate, the mass of epichlorohydrin accounts for 5-10% of the mass of the intermediate, and the epoxidation reaction is carried out at 50-60° C. for 1-2 hours under the catalysis of a 10-15% NaOH aqueous solution 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 vacuum ≤10 kPa for 30-60 min to remove residual solvent and obtain the target modified epoxy resin.

9. The energy-saving, environmentally 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, the maleic anhydride grafting rate is 1.0%-2.5%, and the melt flow rate is 1-5g / 10min.

10. A process for preparing the energy-saving, environmentally friendly, durable and highly viscous modified asphalt according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step t1: pretreatment of the matrix asphalt: heating the matrix asphalt to 160-170° C., adding the ionic liquid, and stirring at 800-1000 rpm for 15 minutes to promote uniform dispersion of the ionic liquid; Step t2: Dispersing the nanocellulose: Mix the nanocellulose with a compatibilizer, add an appropriate amount of xylene, and ultrasonically disperse for 30 minutes at a power of 200-300W to form a stable suspension. Add the suspension to the pretreated asphalt, heat it to 170-180°C, and high-speed shear it at 5000-6000 rpm for 30 minutes to evenly distribute the nanocellulose. Step t3: Blending the 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 rpm for 20 minutes to promote the cross-linking reaction; Step t4, antioxidant addition and ultrasonic treatment: add a hindered phenol antioxidant, continue stirring for 10 minutes, and use an ultrasonic processor to perform secondary dispersion of the asphalt at a power of 300-400W, a frequency of 20-40kHz, and a treatment time of 15 minutes to further refine the microstructure; Step t5: Cooling and testing: Cool naturally to room temperature, test the softening point, Brookfield viscosity, and ductility at 5°C to ensure that the performance meets the standards.

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