A lignin asphalt modifier, one-step method for preparing the same and applications thereof

Abstract

This invention discloses a lignin-based asphalt modifier, its one-step preparation method, and its application. The lignin-based asphalt modifier of this invention, by weight, comprises the following components: 50-95 parts polyethylene, 0.1-30 parts lignin, 0.5-49 parts ethylene-octene copolymer, 0-10 parts additive A, 0-10 parts additive B, 0-10 parts additive C, and 0-10 parts additive D. The addition of lignin in this invention utilizes its three-dimensional network structure to provide support for the matrix asphalt, enhancing the hardness of the asphalt material and improving its high-temperature rutting resistance. The added polyolefin elastomer and additives A, B, C, and D improve the interfacial compatibility between lignin and asphalt or polyethylene, enhance low-temperature ductility, and reduce the low-temperature brittleness of asphalt, thereby improving the overall performance of asphalt.

Description

Technical Field

[0001] This invention belongs to the field of asphalt modification preparation, specifically relating to a lignin asphalt modifier and its one-step preparation method and application. Background Technology

[0002] Asphalt pavement is the common pavement type for highways and major roads in my country, offering advantages such as driving comfort, low noise, and ease of maintenance. In recent years, the rapid construction of my country's highway system and other road transportation networks has led to a significant increase in the demand for asphalt pavement materials. With the increase in freight volume, the service life and load-bearing capacity of asphalt pavements have increased. The heat generated by the friction between vehicle tires and the pavement causes the pavement temperature to rise. Furthermore, asphalt pavements are subject to constant high and low temperature climate changes, making them prone to problems such as high-temperature rutting, low-temperature cracking, and aging, thus affecting their service life. Ordinary asphalt is insufficient to meet the requirements for pavement use; therefore, modifiers are generally added to asphalt pavement materials to address these issues. There are many types of asphalt modifiers; currently, the main types include SBS (styrene-butadiene-styrene triblock copolymer), rubber, and polyolefins.

[0003] SBS-modified asphalt is produced by physically mixing SBS microparticles with asphalt to improve its high and low temperature performance. Currently, SBS modifiers are the mainstream asphalt modifiers due to their combined advantages of high and low temperature performance and good application results. However, the double bonds in the SBS molecular structure are easily damaged and oxidized, resulting in poor anti-aging properties. This leads to weak resistance to high-temperature rutting in asphalt pavements and a short lifespan. This fundamental problem in the molecular structure is difficult to improve through other technologies. Furthermore, the significant differences in composition and structure between SBS microparticles and the base asphalt make them prone to segregation, requiring the addition of additives. Existing technologies generally involve adding sulfur to crosslink SBS with asphalt, thereby improving system stability. However, the addition of sulfur can easily cause a rapid crosslinking reaction between SBS, asphalt, and sulfur, leading to a decrease in the mechanical properties of the modified asphalt. Patent 202311642790.9 proposes a slow-release SBS asphalt modifier with active sulfur as a crosslinking agent. It introduces an additive composed of cellulose acetate, diluent, pore-forming agent, sulfur, vulcanizing agent, activator, and curing agent to prevent rapid polymerization and improve system stability; however, the formulation is complex. SBS modified asphalt requires pre-swelling, grinding, and development processes, resulting in complex application procedures. Furthermore, the problems of poor high-temperature rutting resistance and short service life remain unresolved.

[0004] Rubber-modified asphalt typically uses rubber powder or waste tire rubber powder to improve the low-temperature brittleness, cracking, and ductility of the base asphalt. However, rubber powder prepared from waste tires has an excessively high sulfur content, requiring desulfurization, which reduces its high-temperature resistance. Furthermore, the application of rubber-modified asphalt presents problems such as poor compatibility between rubber and base asphalt, easy sedimentation of rubber powder particles from the blended asphalt mixture, and poor storage stability. Patent 202311102440.3 invented a device for producing high-content rubber-modified asphalt, solving the problems of difficulty in preparing high-content rubber-modified asphalt and its tendency to segregate, but it failed to improve its resistance to high-temperature rutting.

[0005] Polyolefin modified asphalt is generally modified by adding one or more composites such as polyethylene, polypropylene, and polyolefin elastomers to the base asphalt. Asphalt modified with waste plastics PE and PP improves the viscosity and stiffness modulus of the asphalt mixture and enhances its rutting resistance, but its rutting resistance in heavy-load road sections is limited, and the high modulus leads to a decrease in low-temperature crack resistance. Polyolefin modified asphalt also has disadvantages such as poor compatibility with asphalt, resulting in easy segregation, poor thermal storage stability, low-temperature brittleness, and low elastic recovery. Patent ZL02133489.7 mixes polyethylene, polyolefin elastomers and modifiers, and melt-blends them with asphalt to prepare modified asphalt masterbatch for modifying base asphalt; the results of the examples show that the penetration is less than 40 (0.1 mm), which is less than the national standard GB / T15180 index of 41-60 (0.1 mm), and the softening point is greater than 70℃, which is slightly higher than the national standard GB / T15180 (45-55℃). Patent 202310394824.0 describes a composite modifier prepared from waste plastics and waste rubber powder. Its main components are 30-60 parts waste plastics, 20-30 parts waste rubber powder, 5-10 parts styrene-butadiene-styrene block copolymer (SBS), antioxidants, lubricants, and inorganic materials. It is used to improve asphalt performance; however, examples show low penetration and increased softening point. Patent 201710089546.2 describes an asphalt modifier produced using waste polyvinyl chloride (PVC) mulch film, utilizing waste resources and improving asphalt stability. However, its raw materials and production process are complex. Patent 202111506729.2 describes a process that uses ethylene through a multi-step reaction with cyclohexane, methylaluminoxane, and a catalyst to obtain amino-terminated polyethylene, which is used as an asphalt modifier. This overcomes the problem of poor stability in PE asphalt modifiers, but the process is complex and costs are increased. The above technologies show that using polyolefin-modified asphalt can reduce the penetration of the base asphalt and increase the softening point, but it does not improve the high-temperature thermal storage stability, anti-aging properties, or low-temperature anti-brittleness properties.

[0006] With the implementation of environmental protection concepts and the advancement of the "dual carbon" goal, the environmental friendliness and functionalization of asphalt modifiers will become a new trend. The application of biomass materials in asphalt modifiers will further promote its green development. Lignin comes from natural plants, while industrial lignin mainly comes from the pulp and paper industry. Lignin has a three-dimensional network structure and natural anti-ultraviolet and anti-aging functions, which can play an anti-aging and weather-resistant role in materials. Some technicians have used lignin as a modifier component to modify asphalt. Patent 201810490946.9 describes a lignin asphalt modifier made by mixing soluble lignin, insoluble lignin, residual oil and / or vegetable oil in a certain mass ratio. The lignin is obtained from biomass raw materials through pretreatment, enzymatic hydrolysis, saccharification and fermentation, biological degradation and oil extraction. Examples show that this modifier can improve the ductility and softening point of asphalt. Patent 201811022852.5 describes a method for copolymerizing lignin with hydrogenated waste edible oil, adding styrene-butadiene rubber and adjuvants to obtain a lignin-hydrogenated oil copolymer asphalt modifier. Examples show that this modifier has comparable penetration, ductility, and softening point properties to traditional SBS and SBR modified asphalts. Patent 202111102820.8 describes an asphalt modifier containing diatomaceous earth, maleic anhydride-benzyl methacrylate copolymer, phenolic epoxy vinyl ester resin, ethylene-vinyl acetate copolymer, enzymatically hydrolyzed lignin-sulfonated acetone-formaldehyde condensate, sodium dodecyl sulfate, stearic acid, etc. The enzymatically hydrolyzed lignin-sulfonated acetone-formaldehyde condensate is obtained through a multi-step chemical reaction of sodium bisulfite, sodium metabisulfite, acetone, formaldehyde, and enzymatically hydrolyzed lignin / alkali lignin. The lignin acquisition processes described in these patents are complex and costly. Patent 201310388313.4 invented an asphalt modifier containing polyethylene, waste rubber powder, and bio-based filler. The bio-based filler is a dry powder composed of lignin-based organic matter and silicate-based inorganic matter, used to improve the low-temperature resistance of asphalt, but it does not improve the high-temperature rutting resistance. Patent 20141054-2014.6 invented an asphalt modifier containing low-density polyethylene and bio-based filler. The bio-based filler is an organically modified clay prepared from papermaking black liquor and montmorillonite through acid precipitation, flocculation, sedimentation, ball milling, and drying. This patented solution can increase the softening point and dynamic stability of asphalt, but it does not improve the low-temperature brittleness of asphalt.

[0007] Based on the problems of the above-mentioned asphalt modifiers and considering the advantages of lignin, it is necessary to research and develop lignin-based asphalt modifiers, so as to provide a low-cost, natural lignin asphalt modifier that can improve the asphalt's resistance to high-temperature rutting, low-temperature elasticity, and weather resistance. Summary of the Invention

[0008] To address the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a lignin pitch modifier.

[0009] Another object of the present invention is to provide a method for preparing the above-mentioned lignin pitch modifier.

[0010] Another object of the present invention is to provide the application of the above-mentioned lignin pitch modifier.

[0011] The objective of this invention is achieved through the following technical solution:

[0012] A lignin pitch modifier, by mass parts, comprises the following components: 50-95 parts polyethylene, 0.1-30 parts lignin, 0.5-49 parts ethylene-octene copolymer (polyolefin elastomer), 0-10 parts additive A, 0-10 parts additive B, 0-10 parts additive C, and 0-10 parts additive D, wherein additives A, B, C, and D are all not zero.

[0013] Preferably, the lignin pitch modifier is prepared by comprising the following components in parts by mass: 50-95 parts polyethylene, 1-20 parts lignin, 4-30 parts ethylene-octene copolymer (polyolefin elastomer), 0.5-5 parts additive A, 0.5-5 parts additive B, 0.5-5 parts additive C, and 0.5-5 parts additive D.

[0014] The polyethylene is virgin polyethylene or recycled polyethylene, or a mixture of both; the recycled polyethylene is free of metals, fibers and other impurities.

[0015] More preferably, the polyethylene is linear low-density polyethylene.

[0016] Preferably, the lignin is industrial lignin powder, which is at least one of alkali lignin and enzymatically hydrolyzed lignin, and has a particle size distribution of D50 less than 5 μm.

[0017] Preferably, additive A is maleic anhydride, used to modify polyolefin elastomers, and the resulting maleic anhydride-grafted ethylene-octene copolymer is used to further modify lignin.

[0018] Preferably, additive B is at least one of 3-amino-1,2,4-triazole, 1,2,4-triazole and imidazole, used for further modification of maleic anhydride-grafted ethylene-octene copolymer.

[0019] Preferably, the additive C is at least one of zinc chloride, ferric chloride, zinc acetate, and zinc stearate, used to improve the interaction between lignin and polyethylene and maleic anhydride-grafted ethylene-octene copolymer.

[0020] Preferably, the additive D is at least one of rosin ester and rosin ester modified compound, used to improve the interfacial compatibility between lignin and polyethylene.

[0021] Preferably, the lignin pitch modifier further includes color powder, in parts by weight, 0-10 parts.

[0022] More preferably, the pigment is carbon black.

[0023] More preferably, the color powder is 0.2-1 parts.

[0024] The preparation method of the above-mentioned lignin pitch modifier includes the following steps:

[0025] Polyethylene, lignin, ethylene-octene copolymer (polyolefin elastomer), additive A, additive B, additive C, and additive D, or polyethylene, lignin, ethylene-octene copolymer (polyolefin elastomer), additive A, additive B, additive C, additive D, and color powder are mixed evenly in a mixer, added to a twin-screw extruder for melt blending, and then extruded and granulated to obtain a lignin pitch modifier.

[0026] Preferably, the mixing time in the mixer is 1-5 minutes, and the rotation speed is 200-2000 r / min.

[0027] Preferably, the melt blending temperature is 150-190℃, the screw speed is 50-200 r / min, and the vacuum degree is 0-(-0.08) MPa.

[0028] The above-mentioned lignin asphalt modifier is used in asphalt.

[0029] Preferably, in the application, the mixture comprises 0.1-10 parts by weight of the above-mentioned lignin pitch modifier and 90-99.9 parts by weight of the base pitch.

[0030] More preferably, in the application, the mixture comprises 0.5-7 parts by weight of the above-mentioned lignin pitch modifier and 93-99.5 parts by weight of the base pitch.

[0031] Preferably, the specific method of application is as follows: heating the base asphalt to 120-200℃, adding the above-mentioned lignin asphalt modifier and mixing evenly to obtain an asphalt composition for construction.

[0032] More preferably, the mixing speed is 2000-5000 r / min and the stirring time is 2-10 min.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] (1) The lignin asphalt modifier provided by this invention has a simple preparation process, low equipment requirements, uses biomass materials, and can use recycled waste polyethylene as raw material, reducing costs. At the same time, it can promote the recycling of resources and improve resource utilization, which has environmental significance. The lignin asphalt modifier prepared by this invention is a dry granular material, which can be directly added to the base asphalt. It is easy to operate and easy to carry out on-site construction.

[0035] (2) The addition of lignin in this invention can provide support for the matrix asphalt using its three-dimensional network structure, enhance the hardness of the asphalt material, and improve its high-temperature rutting resistance. Furthermore, lignin has good UV resistance and anti-aging properties, and can act as an antioxidant in asphalt to delay road aging and extend the service life of asphalt pavements. The added polyolefin elastomer and additive A are melt-blended and in-situ grafted, while additive B is further melt-modified in-situ. As an interface modifier for lignin, it can improve the compatibility of lignin in asphalt and enhance the stability of the asphalt material. Simultaneously, the polyolefin elastomer can provide low-temperature ductility for asphalt pavements and reduce the low-temperature brittleness of asphalt. Additive C, as an interface modifier, enables the formation of interfacial coordination bonds between lignin and the polymer, strengthening the interaction between lignin and the polymer, and further improving the compatibility of lignin in asphalt. Additive D is an auxiliary interface modifier, enhancing the interaction between the polymer and aggregates, and further improving the compatibility between lignin and asphalt. The lignin pitch modifier prepared from the above raw materials constructs a synergistic coordination crosslinking network, which can provide skeletal support for pitch materials and produce excellent high and low temperature resistance. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0037] Unless otherwise specified in the embodiments of this invention, the conditions shall be performed according to conventional conditions or conditions recommended by the manufacturer. All raw materials and reagents used, unless otherwise specified, are commercially available products.

[0038] The parts mentioned in the embodiments and comparative examples of this invention refer to parts by mass, and the parts can be scaled up or down proportionally.

[0039] Example 1

[0040] 95 parts of polyethylene (Guangzhou Petrochemical M2320), 1 part of alkali lignin powder (D50 less than 5μm), 4 parts of polyolefin elastomer (Dow Chemical 8150), 0.5 parts of maleic anhydride, 0.5 parts of 3-amino-1,2,4-triazole, 0.5 parts of zinc chloride, and 0.5 parts of rosin ester were mixed in a mixer for 2 minutes at a speed of 500 r / min.

[0041] The resulting mixture is added to a twin-screw extruder for melt and shear blending, fusing them into a single unit. The melt blending temperature is 180℃, the screw speed is 50 r / min, and the vacuum degree is -0.05 MPa. The melt blend is extruded through the extruder into strands, and then water-cooled, air-dried, and pelletized to prepare the lignin asphalt modifier.

[0042] Add 0.5 parts of the lignin asphalt modifier prepared above to 99.5 parts of molten base asphalt at a melting temperature of 185℃, stir evenly at a speed of 4000 r / min for 5 min; and the asphalt composition for construction can be obtained.

[0043] Example 2

[0044] 95 parts of polyethylene (Guangzhou Petrochemical M2320), 1 part of alkali lignin powder (D50 less than 5μm), 4 parts of polyolefin elastomer (Dow Chemical 8150), 0.5 parts of maleic anhydride, 0.5 parts of 3-amino-1,2,4-triazole, 0.5 parts of zinc chloride, and 0.5 parts of rosin ester were mixed in a mixer for 2 minutes at a speed of 500 r / min.

[0045] The resulting mixture is added to a twin-screw extruder for melt and shear blending, fusing them into a single unit. The melt blending temperature is 180℃, the screw speed is 50 r / min, and the vacuum degree is -0.05 MPa. The melt blend is extruded through the extruder into strands, and then water-cooled, air-dried, and pelletized to prepare the lignin asphalt modifier.

[0046] The 7 parts of lignin asphalt modifier prepared above were added to 93 parts of molten base asphalt at a melting temperature of 185°C. The mixture was stirred evenly at a speed of 4000 r / min for 5 min to obtain an asphalt composition for construction.

[0047] Example 3

[0048] Mix 50 parts of polyethylene (Guangzhou Petrochemical M2320), 20 parts of alkali lignin powder (D50 less than 5μm), 30 parts of polyolefin elastomer (Dow Chemical 8150), 5 parts of maleic anhydride, 5 parts of 3-amino-1,2,4-triazole, 5 parts of zinc chloride, and 5 parts of rosin ester in a mixer for 2 minutes at a speed of 500 r / min.

[0049] The resulting mixture is added to a twin-screw extruder for melt and shear blending, fusing them into a single unit. The melt blending temperature is 180℃, the screw speed is 50 r / min, and the vacuum degree is -0.05 MPa. The melt blend is extruded through the extruder into strands, and then water-cooled, air-dried, and pelletized to prepare the lignin asphalt modifier.

[0050] Add 0.5 parts of the lignin asphalt modifier prepared above to 99.5 parts of molten base asphalt at a melting temperature of 185℃, stir evenly at a speed of 4000 r / min for 5 min; and the asphalt composition for construction can be obtained.

[0051] Example 4

[0052] Mix 50 parts of polyethylene (Guangzhou Petrochemical M2320), 20 parts of alkali lignin powder (D50 less than 5μm), 30 parts of polyolefin elastomer (Dow Chemical 8150), 5 parts of maleic anhydride, 5 parts of 3-amino-1,2,4-triazole, 5 parts of zinc chloride, and 5 parts of rosin ester in a mixer for 2 minutes at a speed of 500 r / min.

[0053] The resulting mixture is added to a twin-screw extruder for melt and shear blending, fusing them into a single unit. The melt blending temperature is 180℃, the screw speed is 50 r / min, and the vacuum degree is -0.05 MPa. The melt blend is extruded through the extruder into strands, and then water-cooled, air-dried, and pelletized to prepare the lignin asphalt modifier.

[0054] The 7 parts of lignin asphalt modifier prepared above were added to 93 parts of molten base asphalt at a melting temperature of 185°C. The mixture was stirred evenly at a speed of 4000 r / min for 5 min to obtain an asphalt composition for construction.

[0055] Example 5

[0056] 70 parts of polyethylene (Guangzhou Petrochemical M2320), 10 parts of alkali lignin powder (D50 less than 5μm), 20 parts of polyolefin elastomer (Dow Chemical 8150), 2.5 parts of maleic anhydride, 2.5 parts of 3-amino-1,2,4-triazole, 2.5 parts of zinc chloride, and 2.5 parts of rosin ester were mixed in a mixer for 2 minutes at a speed of 500 r / min.

[0057] The resulting mixture is added to a twin-screw extruder for melt and shear blending, fusing them into a single unit. The melt blending temperature is 180℃, the screw speed is 50 r / min, and the vacuum degree is -0.05 MPa. The melt blend is extruded through the extruder into strands, and then water-cooled, air-dried, and pelletized to prepare the lignin asphalt modifier.

[0058] Add the 3.5 parts of lignin asphalt modifier obtained above to 96.5 parts of molten base asphalt at a melting temperature of 185℃, stir evenly at a speed of 4000 r / min for 5 min; and the asphalt composition for construction can be obtained.

[0059] Example 6

[0060] 95 parts of polyethylene (Guangzhou Petrochemical M2320), 1 part of alkali lignin powder (D50 less than 5μm), 4 parts of polyolefin elastomer (Dow Chemical 8150), 0.5 parts of maleic anhydride, 0.5 parts of 3-amino-1,2,4-triazole, 0.5 parts of zinc chloride, 0.5 parts of rosin ester and 0.5 parts of carbon black (N330) were mixed in a mixer for 2 minutes at a speed of 500 r / min.

[0061] The resulting mixture is added to a twin-screw extruder for melt and shear blending, fusing them into a single unit. The melt blending temperature is 180℃, the screw speed is 50 r / min, and the vacuum degree is -0.05 MPa. The melt blend is extruded through the extruder into strands, and then water-cooled, air-dried, and pelletized to prepare the lignin asphalt modifier.

[0062] Add 0.5 parts of the lignin asphalt modifier prepared above to 99.5 parts of molten base asphalt at a melting temperature of 185℃, stir evenly at a speed of 4000 r / min for 5 min; and the asphalt composition for construction can be obtained.

[0063] Comparative Example 1

[0064] 95 parts of polyethylene (Guangzhou Petrochemical M2320), 4 parts of polyolefin elastomer (Dow Chemical 8150), 0.5 parts of maleic anhydride, 0.5 parts of 3-amino-1,2,4-triazole, 0.5 parts of zinc chloride, and 0.5 parts of rosin ester were mixed in a mixer for 2 minutes at a speed of 500 r / min.

[0065] The resulting mixture is added to a twin-screw extruder for melt and shear blending, fusing them into a single unit. The melt blending temperature is 180℃, the screw speed is 50r / min, and the vacuum degree is -0.05MPa. The melt blend is extruded through the extruder into strands, and then water-cooled, air-dried, and pelletized to prepare a lignin-free asphalt modifier.

[0066] Add 0.5 parts of the lignin asphalt modifier prepared above to 99.5 parts of molten base asphalt at a melting temperature of 185℃, stir evenly at a speed of 4000 r / min for 5 min; and the asphalt composition for construction can be obtained.

[0067] Comparative Example 2

[0068] 95 parts of polyethylene (Guangzhou Petrochemical M2320), 1 part of alkali lignin powder (D50 less than 5μm), and 4 parts of polyolefin elastomer (Dow Chemical 8150) were mixed in a mixer for 2 minutes at a speed of 500 r / min.

[0069] The resulting mixture was added to a twin-screw extruder for melt and shear blending until it was integrated. The melt blending temperature was 180℃, the screw speed was 50r / min, and the vacuum degree was -0.05MPa. The melt blend was extruded through the extruder into strands, and after water cooling, air drying, and pelletizing, the interface-free lignin pitch modifier was prepared.

[0070] Add 0.5 parts of the lignin asphalt modifier prepared above to 99.5 parts of molten base asphalt at a melting temperature of 185℃, stir evenly at a speed of 4000 r / min for 5 min; and the asphalt composition for construction can be obtained.

[0071] The asphalt used in the comparative examples was No. 70 road petroleum asphalt with an asphalt-aggregate ratio of 4.3 wt%. The aggregate mass ratio was: 10-20 mm aggregate: 10-15 mm aggregate: 5-10 mm aggregate: 0-3 mm stone chips: mineral powder = 33:11:28:27:1.

[0072] The test methods for dynamic stability, penetration, softening point, etc. in the rutting test refer to the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" JTG E 20-2011. The specific data are shown in Table 1.

[0073]

[0074] As shown in Table 1, the lignin-based asphalt modifier prepared in this invention, when used to modify asphalt pavements, exhibits high-temperature rutting resistance far exceeding the latest standard of 5000 cycles / mm. Its penetration is lower than that of the embodiments in patents 202410417728.8, 202310394824.0, 201310388313.4, 201810490946.9, and 201811022852.5, while its softening point is higher. The decrease in penetration and increase in softening point indicate increased plasticity, shear strength, and improved high-temperature stability. This demonstrates that the asphalt modifier prepared in this invention effectively improves the high-temperature and low-temperature resistance of asphalt, exhibiting excellent overall performance. Adding lignin-based asphalt modifiers directly during asphalt mixing significantly reduces mixing time and construction difficulty, lowers energy consumption, eliminates dust pollution, and prevents segregation within the system. This invention enables the application of biomass materials—lignin—and recycled waste plastics.

[0075] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A lignin-based pitch modifier, characterized in that, It is prepared by weight of the following components: 50-95 parts polyethylene, 0.1-30 parts lignin, 0.5-49 parts ethylene-octene copolymer, 0-10 parts additive A, 0-10 parts additive B, 0-10 parts additive C, and 0-10 parts additive D, wherein additives A, B, C, and D are not all 0. Additive A is maleic anhydride; The additive B is at least one of 3-amino-1,2,4-triazole, 1,2,4-triazole and imidazole; The additive C is at least one of zinc chloride, ferric chloride, zinc acetate, and zinc stearate; The additive D is at least one of rosin ester and rosin ester modified compound.

2. The lignin pitch modifier according to claim 1, characterized in that, It is prepared by weight of the following components: 50-95 parts polyethylene, 1-20 parts lignin, 4-30 parts ethylene-octene copolymer, 0.5-5 parts additive A, 0.5-5 parts additive B, 0.5-5 parts additive C, and 0.5-5 parts additive D.

3. The lignin pitch modifier according to claim 1 or 2, characterized in that, The lignin is at least one of alkali lignin and enzymatically hydrolyzed lignin, and the particle size distribution is D50 less than 5 μm.

4. A lignin pitch modifier according to claim 1 or 2, characterized in that, The polyethylene is linear low-density polyethylene.

5. A lignin pitch modifier according to claim 1 or 2, characterized in that, The lignin pitch modifier also includes color powder, in parts by weight, 0-10 parts.

6. A method for preparing a lignin pitch modifier according to any one of claims 1-5, characterized in that, Includes the following steps: Polyethylene, lignin, ethylene-octene copolymer, additive A, additive B, additive C, and additive D, or polyethylene, lignin, ethylene-octene copolymer, additive A, additive B, additive C, additive D, and color powder are mixed evenly in a mixer, added to a twin-screw extruder for melt blending, and then extruded and granulated to obtain a lignin pitch modifier.

7. The method for preparing a lignin pitch modifier according to claim 6, characterized in that, The mixing time in the mixer is 1-5 minutes, and the rotation speed is 200-2000 r / min; The melt blending temperature is 150-190℃, the screw speed is 50-200 r / min, and the vacuum degree is 0-(-0.08) MPa.

8. The application of the lignin pitch modifier according to any one of claims 1-5 in asphalt.

9. The application of the lignin-based asphalt modifier according to claim 8 in asphalt, characterized in that, Based on parts by weight, it comprises 0.1-10 parts of the lignin pitch modifier according to any one of claims 1-5 and 90-99.9 parts of the base pitch; The specific method is as follows: heat the base asphalt to 120-200℃, add the lignin asphalt modifier according to any one of claims 1-5 and mix evenly to obtain an asphalt composition for construction.

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