A modified asphalt and a method for preparing and using the same

Abstract

The application discloses modified asphalt and a preparation method and application thereof. The modified asphalt comprises the following components in parts by weight: 100 parts of base asphalt, 3-6 parts of a compatilizer, 4-7 parts of a composite SBS modifier, and 0.5-8 parts of a clean-smelling slow-release stabilizer. The clean-smelling slow-release stabilizer comprises a shell material and a core material, wherein the shell material comprises a composite shell material of nano-silicon dioxide / cyclodextrin, and the core material comprises a clean-smelling agent and a stabilizer. The modified asphalt has good heat storage stability, and after thin-film oven aging, the softening point is reduced by less than 5 DEG C, the elongation, the penetration and other performances all meet the technical indexes of race track asphalt, and the release amount of toxic and harmful smoke is obviously reduced.

Description

Technical Field

[0001] This invention belongs to the field of modified asphalt, specifically relating to a modified asphalt, its preparation method, and its application. Background Technology

[0002] Modified asphalt for racetracks differs from that for traditional roads, having higher requirements for high and low temperature performance and storage stability. Taking the Ningbo F2 circuit as an example, its surface asphalt requires an SBS content of no less than 5.0% based on the base asphalt content, a softening point of no less than 75℃, and a penetration of no more than 65 ± 0.1 mm at 25℃. Not only are the requirements for ductility and segregation at 5℃ before and after aging far higher than those for ID-grade modified asphalt, but it also includes new requirements such as a ductility greater than 100 cm at 25℃, which are not required for ID-grade modified asphalt.

[0003] Furthermore, the newly revised Chinese transportation industry standard, *Technical Specification for Construction of Asphalt Pavement on Highways* (JTG 3640), has added an indicator for the change in softening point before and after short-term aging. The new standard requires that the softening point increase after short-term aging should not exceed 8℃, and the decrease should not exceed 5℃. This requirement presents a challenge in the preparation of modified asphalt. Research shows that SBS modified asphalt is more prone to a decrease in softening point after short-term aging, with the decrease exceeding 5℃. The change in softening point after aging of modified asphalt is determined by numerous factors, including the properties of the base asphalt, the degree of SBS crosslinking, the stability of the network structure, and the aging degradation of SBS. Moreover, it is difficult to simultaneously consider the change in softening point with other indicators, which significantly increases the difficulty of preparing modified asphalt.

[0004] Furthermore, the preparation, mixing, and paving temperatures of modified asphalt are much higher than those of ordinary road asphalt. The high temperatures during these processes cause modified asphalt materials to release large amounts of toxic, harmful, and irritating fumes into the air, polluting the environment, posing challenges to the survival of plants and animals, and affecting human health. Related studies indicate that asphalt fumes are mainly composed of low- and medium-molecular-weight hydrocarbons and their derivatives, primarily PAHs, nitrogen-containing compounds, and sulfur-containing compounds, including substances such as benzo[a]benzene. [a] Strong carcinogens such as pyrene and gases with irritating odors such as NH3, H2S, and thiophene.

[0005] CN105038280B discloses an SBS-modified asphalt and its preparation method. This method uses polyphosphoric acid to replace part of the SBS modifier in the asphalt modification. While this reduces modification costs to some extent, the low-temperature ductility and softening point are low, and the softening point varies excessively. Furthermore, the amount of SBS modifier added to the modified asphalt used in racing tracks is limited, and polyphosphoric acid cannot be used as a substitute. CN112300586A discloses an SBS-modified asphalt stabilizer and SBS-modified asphalt. The modified asphalt prepared by this method can inhibit the aging of modified asphalt, but it is detrimental to ductility at 25℃ and cannot inhibit changes in the softening point. Moreover, neither of these patents considers the smoke pollution problems in various stages of modified asphalt production, transportation, and use.

[0006] In summary, the above methods cannot simultaneously consider the high-temperature stability and low-temperature ductility of modified asphalt, cannot solve the problem of excessive changes in softening point under high SBS content, and the modified asphalt prepared cannot meet the requirements of track asphalt indicators, nor can they solve the problem of flue gas release from modified asphalt. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a modified asphalt, its preparation method, and its applications. The modified asphalt of this invention exhibits good thermal storage stability; after aging in a thin-film oven, its softening point decreases by less than 5°C. Its ductility, penetration, and other properties meet the technical specifications for racing track asphalt, and the release of toxic and harmful fumes is significantly reduced.

[0008] The first aspect of this invention provides a modified asphalt, comprising, by weight, the following raw material components:

[0009] Base bitumen: 100 parts;

[0010] Compatibilizer: 3-6 parts, preferably 3.5-5 parts;

[0011] Composite SBS modifier: 4-7 parts, preferably 5-6.5 parts;

[0012] Odor-neutralizing sustained-release stabilizer: 0.5–8 parts, preferably 3–7 parts;

[0013] The deodorizing and slow-release stabilizer includes a shell material and a core material, wherein the shell material is a composite shell material including nano-silica / cyclodextrin, and the core material includes a deodorizing agent and a stabilizer.

[0014] Furthermore, the properties of the base asphalt include: a penetration of 80–85 mm at 25°C, a softening point of 42–48°C, a dynamic viscosity of 155 Pa·s–165 Pa·s at 60°C, and a residual ductility of 10 cm–15 cm at 10°C. By mass fraction, the saturated components account for 13.1%–16.4%, the aromatic components for 49.6%–54.5%, the resins for 22.4%–27.1%, and the asphaltenes for 7.3%–12.1%.

[0015] Furthermore, the base bitumen is preferably obtained by vacuum distillation of one or more of the following: crude oil from sand, Kuwait crude oil, and Basra crude oil.

[0016] Furthermore, the compatibilizer is an adhesive obtained after solvent deasphalting.

[0017] Furthermore, the compatibilizer is an adhesive obtained through conventional solvent deasphalting processes in the art.

[0018] Furthermore, the properties of the compatibilizer include: a kinematic viscosity of 50 mmHg at 100°C. 2 / s~65mm 2 / s, flash point is 206℃~220℃, by mass fraction, saturated fraction accounts for 30%~42%, aromatic fraction accounts for 48%~57%, resin accounts for 8%~13%, asphaltene content is less than 2%; weight average molecular weight is 1990~2140, molecular weight distribution width is 1.6~3.7.

[0019] Furthermore, the composite SBS modifier is an SBS modifier that has undergone pre-degradation extrusion treatment.

[0020] Furthermore, the composite SBS modifier includes linear SBS modifiers and star-shaped SBS modifiers. The linear SBS modifier accounts for 45% to 70% of the total mass of the composite SBS modifier.

[0021] Furthermore, the pre-degradation extrusion treatment method includes: putting linear SBS modifier and star-shaped SBS modifier into a grinding mill, shearing and grinding, and extruding and granulating to obtain composite SBS modifier.

[0022] Furthermore, the linear SBS modifier has the following properties: a styrene to butadiene mass ratio of 1:(4-7.3) and a tensile strength of 280-350 kg / cm². 2 Its elongation at break is 800%–910%, and its Shore hardness is 75±6HA.

[0023] Furthermore, the star-shaped SBS modifier has the following properties: a styrene to butadiene mass ratio of 1:(1.2-1.8) and a tensile strength of 200-300 kg / cm².2 Its elongation at break is 720%–800%, and its Shore hardness is 90±5HA.

[0024] Furthermore, the particle size of the deodorizing sustained-release stabilizer is 1–5 μm.

[0025] Furthermore, the mass ratio of the shell material to the core material of the deodorizing slow-release stabilizer is 1:(0.5-2).

[0026] Furthermore, the shell material of the deodorizing sustained-release stabilizer is a composite shell material comprising nano-silica / cyclodextrin, wherein the mass ratio of silica to cyclodextrin is 1:(0.2-0.6).

[0027] Further, the cyclodextrin is at least one selected from carboxymethyl-β-cyclodextrin, hydroxyethyl-β-cyclodextrin, hydroxypropyl-β-cyclodextrin, and 2-hydroxypropyl-β-cyclodextrin.

[0028] Furthermore, the mass ratio of the neutralizing agent to the stabilizer is 1:(0.6-1.2).

[0029] Furthermore, the deodorizing agent includes one or more of ketones, esters, aldehydes, and ethers.

[0030] Furthermore, the ketone is an aliphatic ketone with more than 4 carbon atoms; the aliphatic ketone with more than 4 carbon atoms is selected from one or more of 3-hydroxy-2-butanone, 2,3-butanedione, and 3-penten-2-one.

[0031] Further, the esters are selected from fatty acid esters with more than 5 carbon atoms and lactones with more than 5 carbon atoms; the fatty acid esters with more than 5 carbon atoms are selected from one or more of butyl acetate, isoamyl acetate, leaf ester acetate, leaf ester isobutyrate, ethyl isovalerate, butyl hexanoate, ethyl laurate, and ethyl octanoate; the lactones with more than 5 carbon atoms are selected from one or more of γ-valerolactone, γ-caprolactone, γ-octyllactone, and γ-nonalactone.

[0032] Further, the aldehydes are selected from aromatic aldehydes with more than 6 carbon atoms and terpenoid aldehydes with more than 8 carbon atoms; the aromatic aldehydes with more than 6 carbon atoms are selected from one or more of benzaldehyde, phenylacetaldehyde, o-methoxy-p-methylbenzaldehyde, and 2-methyl-3-(3,4-methylenedioxyphenyl)propanal; the terpenoid aldehydes with more than 8 carbon atoms are selected from one or more of citral, citronellol, and hydroxycitronellol.

[0033] Furthermore, the ether is an aromatic ether with more than 9 carbon atoms; the aromatic ether with more than 9 carbon atoms is selected from one or more of 4-hydroxy-3-methylallylbenzene and 4-propenyl anisole.

[0034] Furthermore, the stabilizer includes a primary stabilizer and a secondary stabilizer. The primary stabilizer is elemental sulfur, and the secondary stabilizer is at least one of tetramethylthiuram disulfide, morpholino disulfide, ferric chloride, ferric oxide, ferrous chloride, copper chloride, nano zinc oxide, montmorillonite, and octadecyl alcohol 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, preferably at least one of tetramethylthiuram disulfide, morpholino disulfide, ferrous chloride, and nano zinc oxide.

[0035] Furthermore, the mass ratio of the primary stabilizer to the secondary stabilizer is 1:(2-5).

[0036] A second aspect of the present invention provides a method for preparing the above-mentioned odor-neutralizing polymer-modified asphalt, comprising:

[0037] (1) Preparation of composite SBS modifier;

[0038] (2) Mix a portion of the composite SBS modifier with a compatibilizer, and then shear and develop it for later use;

[0039] (3) Heat the base asphalt to a molten state, mix it with the remaining composite SBS modifier, shear it, and then add the material prepared in step (2) and stir to develop.

[0040] (4) Add a neutralizing slow-release stabilizer to the material obtained in step (3), and continue stirring to develop, to obtain modified asphalt.

[0041] Furthermore, in step (1), the preparation process of the composite SBS modifier includes:

[0042] Linear SBS modifier and star-shaped SBS modifier are put into a grinding mill, sheared and ground, and then extruded and granulated to obtain composite SBS modifier.

[0043] Furthermore, in the preparation process of the composite SBS modifier, the shearing and grinding temperature is 120℃~150℃, preferably 125℃~146℃; the shearing and grinding time is 20~40min. The extrusion granulation preferably uses a twin-screw extruder. The number of extrusions is 1~5 times, preferably 3 times, wherein the first extrusion temperature is 120℃~130℃, and the screw speed is 180~300r / min; the second extrusion temperature is between 130℃~140℃, and the screw speed is between 320~450r / min; the third extrusion temperature is between 145℃~160℃, and the screw speed is between 500~650r / min, wherein the temperature of each subsequent extrusion is higher than the temperature of the previous extrusion.

[0044] Further, in step (2), the amount of the partially composite SBS modifier is 30% to 70% of the total weight of the composite SBS modifier, preferably 40% to 65%. The shear rate is 3000 to 5000 r / min, preferably 3000 to 4500 r / min, the shearing time is 20 to 40 min, and the required temperature during shearing is 120℃ to 145℃, preferably 125℃ to 135℃. The development can be static development, the development temperature is 130℃ to 145℃, and the development time is 4 h to 8 h.

[0045] Further, in step (3), the heating temperature of the base asphalt is 130–145°C; both shearing and stirring development are carried out under a protective gas, preferably an inert gas and / or N2. The shearing rate is 4000–6000 r / min, preferably 4000–5500 r / min, the shearing time is 60–80 min, and the required temperature during shearing is 170–185°C. The stirring speed is 600–800 r / min, the development time is 20–40 min, and the development temperature is 150°C–195°C, preferably 170°C–180°C.

[0046] Further, in step (4), the deodorizing slow-release stabilizer is preferably added in several portions, with an interval of 20 to 40 minutes between each addition; more preferably, it is added in two separate additions. The stirring speed is 600 to 800 r / min, the development time is 4 to 6 hours, and the development temperature is 150°C to 195°C, preferably 175°C to 185°C.

[0047] Further, in step (4), the preparation method of the deodorizing sustained-release stabilizer includes:

[0048] a: Mix cyclodextrin, surfactant and solvent, stir, then wash and freeze dry to obtain pretreated cyclodextrin;

[0049] b: Mix the stabilizer and the deodorizing agent, stir, and obtain the core material mixture;

[0050] c: Mix the core material mixture obtained in step b with the pretreated cyclodextrin and solvent obtained in step a, and stir.

[0051] d: Add silica precursor to the reaction system in step c, stir to obtain Pickering emulsion, adjust pH, continue stirring, age, then filter, wash, freeze dry to obtain deodorizing sustained-release stabilizer.

[0052] Further, the surfactant mentioned in step a is a cationic surfactant, preferably one or more of dodecyl dimethyl benzyl ammonium chloride, hexadecyl trimethyl ammonium bromide, and octadecyl trimethyl ammonium chloride.

[0053] Further, in step a, the solvent is an aprotic solvent with a boiling point >100℃, preferably one or more of formamide, N,N-dimethylformamide, dimethylacetamide, and dimethylphosphoramide, and more preferably formamide.

[0054] Further, in step a, the mass ratio of the cyclodextrin, solvent, and surfactant is (1-10):(10-50):1.

[0055] Further, in step a, the stirring speed is 400-600 rpm; the stirring temperature is 100-200℃; and the stirring time is 4-10 hours.

[0056] Further, in step a, the washing is performed using ethanol. The freeze-drying conditions are: vacuum drying at a temperature of -40°C to -20°C for 4 to 8 hours.

[0057] Furthermore, in step b, the stirring speed is 400-600 rpm, the stirring temperature is 30-70°C, and the stirring time is 3-10 minutes.

[0058] Further, in step c, the solvent is an aprotic solvent with a boiling point >100℃, preferably one or more of formamide, N,N-dimethylformamide, dimethylacetamide, and dimethylphosphoramide, and more preferably formamide.

[0059] Further, in step c, the mass ratio of the core material mixture to the solvent-pretreated cyclodextrin is (1-10):(20-60):1.

[0060] Furthermore, in step c, the stirring speed is 400-600 rpm, the stirring temperature is 40-60°C, and the stirring time is 4-6 hours.

[0061] Further, in step d, the silica precursor is a silicate compound, preferably one or more of methyl silicate, tetraethyl orthosilicate, tetraethyl orthosilicate, and butyl orthosilicate, and more preferably tetraethyl orthosilicate.

[0062] Further, in step d, the mass ratio of the reaction system to the silica precursor is (0.5-2):1.

[0063] Furthermore, in step d, before adjusting the pH, the stirring speed is 400-600 rpm, the stirring temperature is 40-60°C, and the stirring time is 4-6 hours.

[0064] Furthermore, in step d, the pH can be adjusted using a dilute acid, such as dilute hydrochloric acid. After adjusting the pH, the stirring speed is 400–600 rpm, the stirring temperature is 40–60°C, and the stirring time is 4–6 hours.

[0065] Furthermore, in step d, the filtration and washing are performed using conventional methods in the art.

[0066] Further, in step d, the aging conditions are: standing at 40–60°C for 12–30 hours. The freeze-drying conditions are: vacuum drying at -40–-20°C for 4–8 hours.

[0067] A third aspect of the present invention provides an application of the modified asphalt in a racetrack.

[0068] Compared with the prior art, the present invention has the following advantages:

[0069] (1) The present invention uses compatibilizer, composite SBS modifier, odor-neutralizing slow-release stabilizer and base asphalt in synergy, which can greatly improve the storage stability of modified asphalt, meet the requirements of high SBS content for track asphalt, and avoid excessive changes in softening point, making it particularly suitable as track asphalt.

[0070] (2) The present invention selects SBS with different structural properties for compounding and use. The composite SBS modifier is not a simple mechanical mixing of two SBS modifiers, but an SBS modifier that has undergone pre-degradation extrusion treatment and is then combined with other components, so that the modified asphalt has better high-temperature stability and low-temperature elongation, avoiding the problem of significant decrease in softening point after short-term aging.

[0071] (3) The core material of the odor-neutralizing slow-release stabilizer used in this invention includes main and auxiliary stabilizer components and odor-neutralizing active components. The odor-neutralizing agent, as a core material component, avoids evaporation loss when added directly. The main stabilizer and auxiliary stabilizer have different reaction rates and reaction product stability with the composite SBS modifier, and both are released slowly, avoiding excessively vigorous initial crosslinking reaction. This effectively controls the integrity and strength of the composite SBS modifier network structure, which is beneficial to improving the medium-temperature ductility and storage stability of modified asphalt. The stabilizer and odor-neutralizing active agent are tightly combined. Once the sulfide products generated by the unreacted stabilizer are generated, they can be quickly and accurately captured and converted, generating compounds with higher stability and boiling point through nucleophilic reactions. In contrast, traditional odor-neutralizing agents are unevenly dispersed in the asphalt system and only briefly come into contact with harmful gas molecules during mechanical stirring, resulting in limited ability to capture harmful gas molecules. Compared with this, the odor-neutralizing agent of this invention has higher conversion efficiency and conversion degree, and is more effective in reducing the release of toxic and harmful fumes.

[0072] (4) The shell material of the odor-neutralizing slow-release stabilizer used in this invention contains pretreated cyclodextrin, which can not only make the odor-neutralizing slow-release stabilizer uniformly and stably dispersed in the asphalt system and improve the uniformity of the cross-linking reaction, but also capture trace amounts of harmful light components in the matrix asphalt before the core material is released, and capture harmful components generated by the cross-linking reaction in conjunction with the core material after the core material is released, while controlling the toxic and harmful fumes generated before and during the preparation of modified asphalt. Detailed Implementation

[0073] The technical solution of the present invention is further described below through embodiments, but these embodiments cannot limit the scope of protection of the present invention, and the percentages involved are mass fractions.

[0074] In this invention, conventional indicators such as softening point and penetration are tested according to the requirements of the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering JTG E20-2011". The sulfides in the asphalt flue gas described in this invention are tested by gas chromatography according to the national standard GBT14678-1993, "Determination of Hydrogen Sulfide, Methanethiol, Dimethyl Sulfide and Dimethyl Disulfide in Air Quality".

[0075] Example 1: Preparation of Odor-Cleansing Slow-Release Stabilizer I:

[0076] a: Add carboxymethyl-β-cyclodextrin powder, dodecyl dimethyl benzyl ammonium chloride, and formamide to the first container in a mass ratio of 2:1:30. Stir at 180℃ and 400 rpm for 5 hours, then wash with ethanol 3 times and vacuum dry at -30℃ for 5 hours to obtain pretreated cyclodextrin for later use.

[0077] b: Add the deodorizing agent (3-hydroxy-2-butanone, acetic acid leaf ester, γ-octyl lactone, o-methoxy-p-methylbenzaldehyde, citral, 4-hydroxy-3-methylallylbenzene mixed in a mass ratio) and the stabilizer (the main stabilizer is elemental sulfur, and the auxiliary stabilizer is tetramethylthiuram disulfide, with a mass ratio of 1:3) to the second container. After mixing at a mass ratio of 1:0.8, stir at 400 rpm for 10 min at 50°C to obtain the core material mixture.

[0078] c: Add the pretreated cyclodextrin powder and formamide obtained in step a to the reaction system in step b. The mass ratio of the core material mixture, pretreated cyclodextrin and formamide is 2:1:20. Continue stirring at 400 r / min for 5 hours at 50°C.

[0079] d: Add tetraethyl orthosilicate to the reaction system in step c. The mass ratio of the core material mixture to tetraethyl orthosilicate is 1:1. Continue stirring at 400 r / min for 5 hours at 50°C to obtain Pickering emulsion.

[0080] 10wt% dilute hydrochloric acid was slowly added dropwise to the Pickering emulsion using a peristaltic pump until the pH of the reaction system reached 4. The mixture was stirred at 400 r / min for 5 hours at 50°C. After stirring, the mixture was aged at the same temperature for 24 hours. The solid powder in the reaction system was then filtered, washed, and vacuum dried at -30°C for 5 hours to obtain the neutralizing slow-release stabilizer I.

[0081] Example 2: Preparation of Odor-Cleansing Sustained-Release Stabilizer II:

[0082] a: Add carboxymethyl-β-cyclodextrin powder, octadecyltrimethylammonium chloride, and formamide to the first container in a mass ratio of 2:1:30. Stir at 160℃ and 500 rpm for 5 hours, then wash with ethanol 3 times and vacuum dry at -30℃ for 6 hours to obtain pretreated cyclodextrin for later use.

[0083] b: Add the deodorizing agent (3-hydroxy-2-butanone, acetic acid leaf ester, γ-octanolide, o-methoxy-p-methylbenzaldehyde, citral, 4-hydroxy-3-methylallylbenzene mixed in a mass ratio) and the stabilizer (the main stabilizer is elemental sulfur, and the auxiliary stabilizer is nano zinc oxide, with a mass ratio of 1:3) to the second container. After mixing at a mass ratio of 1:0.8, stir at 400 rpm for 10 minutes at 50°C to obtain the core material mixture.

[0084] c: Add the pretreated cyclodextrin powder and formamide obtained in step a to the reaction system in step b. The mass ratio of the core material mixture, pretreated cyclodextrin and formamide is 2:1:20. Continue stirring at 400 r / min for 5 hours at 50°C.

[0085] d: Add tetraethyl orthosilicate to the reaction system in step c. The mass ratio of the core material mixture to tetraethyl orthosilicate is 1:1. Continue stirring at 400 r / min for 5 hours at 50°C to obtain Pickering emulsion.

[0086] 10wt% dilute hydrochloric acid was slowly added dropwise to the Pickering emulsion using a peristaltic pump until the pH of the reaction system reached 4. The mixture was stirred at 400 r / min for 5 hours at 50°C. After stirring, the mixture was aged at the same temperature for 30 hours. The solid powder in the reaction system was then filtered, washed, and vacuum dried at -35°C for 6 hours to obtain the neutralizing slow-release stabilizer II.

[0087] Comparative Example 1: Preparation of Odor-Cleansing Sustained-Release Stabilizer III:

[0088] Same as Example 1, except that the stabilizer does not contain elemental sulfur, but only tetramethylthiuram disulfide.

[0089] Comparative Example 2: Preparation of Odor-Cleansing Sustained-Release Stabilizer IV:

[0090] The deodorizing agent (3-hydroxy-2-butanone, leaf ester acetate, γ-octyl lactone, o-methoxy-p-methylbenzaldehyde, citral, 4-hydroxy-3-methylallylbenzene, etc. in a mass ratio) and the stabilizer (the main stabilizer is elemental sulfur, and the auxiliary stabilizer is tetramethylthiuram disulfide, with a mass ratio of 1:3) were mixed at a mass ratio of 1:0.8 and stirred at 400 rpm for 10 min at 50°C. This mixture was then used directly as the deodorizing slow-release stabilizer IV.

[0091] Example 3

[0092] (1) Linear SBS modifier and star-shaped SBS modifier (linear SBS modifier accounts for 65 wt% of the total amount, and the linear SBS modifier has the following properties: the mass ratio of styrene to butadiene is 20:80, and the tensile strength is 300 kg / cm) 2 The elongation at break is 820%, and the Shore hardness is 75HA. The star-shaped SBS modifier has the following properties: the mass ratio of styrene to butadiene is 40:60, and the tensile strength is 250 kg / cm². 2 A modifier with an elongation at break of 750% and a Shore hardness of 90HA was fed into a grinding mill and sheared and ground at 130℃ for 40 minutes until the two were evenly mixed. The evenly mixed modifier was then extruded and granulated three times. The first extrusion temperature was 125℃ and the screw speed was 200 r / min. The second extrusion temperature was 135℃ and the screw speed was 350 r / min. The third extrusion temperature was 155℃ and the screw speed was 500 r / min, thus obtaining a composite SBS modifier.

[0093] (2) Add 2.1 parts of the composite SBS modifier prepared in step (1) to 4 parts of compatibilizer (the resin obtained by solvent deasphalting process, with a kinematic viscosity of 60 mmHg at 100℃). 2 The sample has a flash point of 212℃ and, by mass fraction, comprises 33% saturated matter, 56.5% aromatic matter, 10% resin, and 0.5% asphaltenes; its weight-average molecular weight is 2090, and its molecular weight distribution width is 2.7. It was sheared at 135℃ for 30 min at a shear rate of 4000 r / min. After shearing, it was allowed to stand in a 135℃ oven for 6 h for later use.

[0094] (3) 100 parts of base asphalt (prepared from pure crude sand, with a penetration of 810.1 mm at 25℃, a softening point of 46℃, a dynamic viscosity of 158 Pa·s at 60℃, and a residual ductility (10℃) of 13 cm, and by mass fraction, saturated components account for 14.1%, aromatic components account for 54.1%, resins account for 23.2%, and asphaltenes account for 8.6%) were heated to a fluid state at 135℃, and 3 parts of the composite SBS modifier prepared in step (1) were added. The mixture was then subjected to high-speed shearing at 175℃ under a N2 atmosphere for 60 min at a shearing rate of 4000 r / min. After shearing, the material prepared in step (2) was added, and the mixture was stirred at 170℃ for 30 min at a stirring speed of 600 r / min.

[0095] (4) Slowly add 1.5 parts of odor-neutralizing slow-release stabilizer I to the material in step (3), and add another 1.5 parts of the same odor-neutralizing slow-release stabilizer I after 30 minutes. Each addition is completed within 10 minutes. After the addition is completed, continue stirring and developing for 4.5 hours. The development temperature is 185℃ and the stirring speed is 800r / min to obtain the final modified asphalt A1.

[0096] Example 4

[0097] (1) Linear SBS modifier and star-shaped SBS modifier (the linear SBS modifier accounts for 70% of the total amount, and the properties of the linear SBS modifier and star-shaped SBS modifier are the same as in Example 3) are put into a grinding mill and sheared and ground at 130°C for 40 minutes until they are evenly mixed. The evenly mixed modifier is extruded and granulated three times. The first extrusion temperature is 125°C and the screw speed is 250 r / min. The second extrusion temperature is 135°C and the screw speed is 350 r / min. The third extrusion temperature is 150°C and the screw speed is 550 r / min to obtain the composite SBS modifier.

[0098] (2) Add 3 parts of the composite SBS modifier prepared in step (1) to 4 parts of compatibilizer (properties are the same as in Example 3), and shear at 135℃ for 30 min at a shear rate of 4000 r / min. After shearing, let it stand in an oven at 135℃ for 5 h for later use.

[0099] (3) Heat 100 parts of base asphalt (properties as in Example 3) to a fluid state at 135°C, add 2.2 parts of the composite SBS modifier prepared in step (1), and shear at high speed for 60 min at 175°C under a N2 atmosphere, with a shear rate of 3500 r / min. After shearing, add the material prepared in step (2), and stir at 170°C for 30 min at a stirring speed of 600 r / min.

[0100] (4) Slowly add 1.2 parts of odor-neutralizing slow-release stabilizer I to the material in step (3), and add 1.8 parts of the same odor-neutralizing slow-release stabilizer I after 30 minutes. Each addition is completed within 10 minutes. After addition, continue stirring and developing for 5.5 hours at a development temperature of 180℃ and a stirring speed of 800r / min to obtain the final modified asphalt A2.

[0101] Example 5

[0102] (1) Linear SBS modifier and star-shaped SBS modifier (the linear SBS modifier accounts for 50% of the total amount, and the linear SBS modifier has the following properties: the mass ratio of styrene to butadiene is 20:80, and the tensile strength is 300 kg / cm²) 2 The elongation at break is 820%, and the Shore hardness is 75HA. The star-shaped SBS modifier has the following properties: the mass ratio of styrene to butadiene is 35:65, and the tensile strength is 260 kg / cm². 2 A modifier with an elongation at break of 757% and a Shore hardness of 93HA was fed into a grinding mill and sheared and ground at 130℃ for 40 minutes until the two were evenly mixed. The evenly mixed modifier was then extruded and granulated three times. The first extrusion temperature was 130℃ and the screw speed was 300 r / min. The second extrusion temperature was 135℃ and the screw speed was 380 r / min. The third extrusion temperature was 160℃ and the screw speed was 600 r / min, thus obtaining a composite SBS modifier.

[0103] (2) Add 2.1 parts of the composite SBS modifier prepared in step (1) to 4 parts of compatibilizer (the resin obtained by solvent deasphalting process, with a kinematic viscosity of 65 mmHg at 100°C). 2 / s, flash point 215℃, by mass fraction, saturated fraction 35%, aromatic fraction 54.5%, resin 10%, asphaltenes 0.5%; weight average molecular weight 2100, molecular weight distribution width 2.4), sheared at 135℃ for 30 min, shear rate 4000 r / min. After shearing, it was placed in a 135℃ oven for 6 h for later use.

[0104] (3) Heat 100 parts of base asphalt (properties as in Example 3) to a fluid state at 135°C, add 3.3 parts of the composite SBS modifier prepared in step (1), and shear at high speed for 60 min at 175°C under a N2 atmosphere with a shear rate of 4000 r / min. After shearing, add the material prepared in step (2), and stir at 170°C for 30 min at a stirring speed of 600 r / min.

[0105] (4) Slowly add 1.2 parts of odor-neutralizing slow-release stabilizer I to the material in step (3), and add 2.2 parts of the same odor-neutralizing slow-release stabilizer I after 30 minutes. Each addition is completed within 10 minutes. After the addition is completed, continue stirring and developing for 5 hours at a development temperature of 180℃ and a stirring speed of 800r / min to obtain the final modified asphalt A3.

[0106] Example 6

[0107] (1) Linear SBS modifier and star-shaped SBS modifier (the linear SBS modifier accounts for 45% of the total amount, and the properties of the linear SBS modifier and star-shaped SBS modifier are the same as in Example 5) are put into a grinding mill and sheared and ground at 130°C for 40 minutes until they are evenly mixed. The evenly mixed modifier is extruded and granulated three times. The first extrusion temperature is 125°C and the screw speed is 280 r / min. The second extrusion temperature is 140°C and the screw speed is 350 r / min. The third extrusion temperature is 150°C and the screw speed is 520 r / min to obtain the composite SBS modifier.

[0108] (2) Add 2.3 parts of the composite SBS modifier prepared in step (1) to 4 parts of compatibilizer (with properties the same as in Example 3), and shear at 135°C for 30 min at a shear rate of 3500 r / min. After shearing, let it stand in an oven at 135°C for 7 h for later use.

[0109] (3) Heat 100 parts of base asphalt (properties as in Example 3) to a fluid state at 135°C, add 3.2 parts of the composite SBS modifier prepared in step (1), and shear at high speed for 60 min at 175°C under a N2 atmosphere with a shear rate of 4000 r / min. After shearing, add the material prepared in step (2), and stir at 175°C for 30 min at a stirring speed of 600 r / min.

[0110] (4) Slowly add 1.1 parts of odor-neutralizing slow-release stabilizer II to the material in step (3). After 30 minutes, add 2 parts of the same odor-neutralizing slow-release stabilizer II. Each addition is completed within 10 minutes. After the addition is completed, continue stirring and developing for 4.5 hours. The development temperature is 185℃ and the stirring speed is 800r / min to obtain the final modified asphalt A4.

[0111] Comparative Example 3

[0112] 100 parts of base asphalt (properties as in Example 3) were heated to a fluid state at 135°C. 4 parts of compatibilizer (properties as in Example 1) and 5.2 parts of linear SBS modifier (same as in Example 3) were added. The mixture was then subjected to high-speed shearing at 175°C for 60 minutes at a shear rate of 4000 r / min. After shearing, 1.5 parts of odor-neutralizing slow-release stabilizer I were slowly added. Another 1.5 parts of the same odor-neutralizing slow-release stabilizer I were added 30 minutes later, with each addition completed within 10 minutes. After addition, the mixture was stirred and allowed to develop for 4.5 hours at a development temperature of 185°C and a stirring speed of 800 r / min to obtain the final modified asphalt B1.

[0113] Comparative Example 4

[0114] 100 parts of base asphalt (properties as in Example 3) were heated to a fluid state at 135°C. 4 parts of compatibilizer (properties as in Example 1) and 5.2 parts of star-shaped SBS modifier and linear SBS modifier (where the linear SBS modifier accounted for 65 wt% of the total, and its properties were the same as in Example 3) were added. The mixture was then subjected to high-speed shearing at 175°C for 60 minutes at a shear rate of 4000 r / min. After shearing, 1.5 parts of odor-neutralizing slow-release stabilizer I were slowly added. 30 minutes later, another 1.5 parts of the same odor-neutralizing slow-release stabilizer I were added, each addition completed within 10 minutes. After addition, stirring and development continued for 4.5 hours at a development temperature of 185°C and a stirring speed of 800 r / min, yielding the final modified asphalt B2.

[0115] Comparative Example 5

[0116] Same as Example 3, except that the odor-neutralizing slow-release stabilizer I is replaced with an equal mass of elemental sulfur to obtain the final modified asphalt B3.

[0117] Comparative Example 6

[0118] Same as Example 3, except that the odor-neutralizing slow-release stabilizer I is replaced with odor-neutralizing slow-release stabilizer III to obtain the final modified asphalt B4.

[0119] Comparative Example 7

[0120] Same as Example 3, except that the odor-neutralizing slow-release stabilizer I is replaced with odor-neutralizing slow-release stabilizer IV to obtain the final modified asphalt B5.

[0121] Test case

[0122] The main property indicators of the odor-free polymer-modified asphalt obtained in the examples and comparative examples were tested, and the specific test results are shown in Table 1.

[0123] Table 1. Main properties of the asphalt materials obtained in the examples and comparative examples.

[0124]

[0125] After measuring the properties in Table 1, the modified asphalt prepared in the examples and comparative examples was stored at 143°C for 0 days, 7 days, and 30 days. Then, an equal mass of the stored asphalt was transferred to a sealed container and flue gas enrichment was carried out at 163°C and 300 rpm for 4 hours. After enrichment, the gas in the sealed container was extracted and the sulfide content in the gas was tested by gas chromatography. The data obtained are shown in Table 2 below.

[0126] Table 2 Gas chromatography sulfide test data

[0127]

[0128] Note: ">max" indicates that the sulfide content exceeds the maximum value measured by the instrument.

[0129] The scope of protection of this invention is not limited to the above embodiments, but is defined by the claims. Those skilled in the art can make appropriate modifications to these embodiments without departing from the technical concept and spirit of this invention, and these modified embodiments are also included within the scope of protection of this invention.

Claims

1. A modified asphalt, characterized in that, The modified asphalt, by weight, comprises the following raw material components: Base bitumen: 100 parts; Compatibilizer: 3-6 parts, preferably 3.5-5 parts; Composite SBS modifier: 4-7 parts, preferably 5-6.5 parts; Odor-neutralizing sustained-release stabilizer: 0.5–8 parts, preferably 3–7 parts; The neutralizing and slow-release stabilizer includes a shell material and a core material, wherein the shell material includes a composite shell material of nano-silica / cyclodextrin, and the core material includes a neutralizing agent and a stabilizer.

2. The modified asphalt according to claim 1, characterized in that, The properties of the base asphalt include: a penetration of 80–85 mm at 25°C, a softening point of 42–48°C, a dynamic viscosity of 155 Pa·s–165 Pa·s at 60°C, and a residual ductility of 10 cm–15 cm at 10°C. By mass fraction, the saturated components account for 13.1%–16.4%, the aromatic components account for 49.6%–54.5%, the resins account for 22.4%–27.1%, and the asphaltenes account for 7.3%–12.1%.

3. The modified asphalt according to claim 1, characterized in that, The compatibilizer has the following properties: kinematic viscosity of 50 mmHg at 100°C. 2 / s~65mm 2 / s, flash point is 206℃~220℃, by mass fraction, saturated fraction accounts for 30%~42%, aromatic fraction accounts for 48%~57%, resin accounts for 8%~13%, asphaltene content is less than 2%; weight average molecular weight is 1990~2140, molecular weight distribution width is 1.6~3.

7.

4. The modified asphalt according to claim 1, characterized in that, The composite SBS modifier includes a linear SBS modifier and a star-shaped SBS modifier; wherein the linear SBS modifier accounts for 45% to 70% of the total mass of the composite SBS modifier; the composite SBS modifier is an SBS modifier that has undergone pre-degradation extrusion treatment.

5. The modified asphalt according to claim 1, characterized in that, The particle size of the deodorizing sustained-release stabilizer is 1–5 μm; And / or, the mass ratio of the shell material to the core material of the neutralizing slow-release stabilizer is 1:(0.5-2).

6. The modified asphalt according to claim 1, characterized in that, The shell material of the deodorizing sustained-release stabilizer is a composite shell material comprising nano-silica / cyclodextrin, wherein the mass ratio of silica to cyclodextrin is 1:(0.2-0.6).

7. The modified asphalt according to claim 1, characterized in that, The deodorizing agent includes one or more of ketones, esters, aldehydes, and ethers; And / or, the ketones are aliphatic ketones with more than 4 carbon atoms; the aliphatic ketones with more than 4 carbon atoms are selected from one or more of 3-hydroxy-2-butanone, 2,3-butanedione, and 3-penten-2-one; And / or, the esters are selected from fatty acid esters with more than 5 carbon atoms and lactones with more than 5 carbon atoms; the fatty acid esters with more than 5 carbon atoms are selected from one or more of butyl acetate, isoamyl acetate, leaf ester acetate, leaf ester isobutyrate, ethyl isovalerate, butyl hexanoate, ethyl laurate, and ethyl octanoate; the lactones with more than 5 carbon atoms are selected from one or more of γ-valerolactone, γ-caprolactone, γ-octyllactone, and γ-nonalactone. And / or, the aldehydes are selected from aromatic aldehydes with more than 6 carbon atoms and terpenoid aldehydes with more than 8 carbon atoms; the aromatic aldehydes with more than 6 carbon atoms are selected from one or more of benzaldehyde, phenylacetaldehyde, o-methoxy-p-methylbenzaldehyde, and 2-methyl-3-(3,4-methylenedioxyphenyl)propanal; the terpenoid aldehydes with more than 8 carbon atoms are selected from one or more of citral, citronellol, and hydroxycitronellol. And / or, the ether is an aromatic ether with more than 9 carbon atoms; the aromatic ether with more than 9 carbon atoms is selected from one or more of 4-hydroxy-3-methylallylbenzene and 4-propenyl anisole.

8. The modified asphalt according to claim 1, characterized in that, The stabilizer includes a primary stabilizer and a secondary stabilizer; the primary stabilizer is elemental sulfur, and the secondary stabilizer is at least one of tetramethylthiuram disulfide, morpholino disulfide, ferric chloride, ferric oxide, ferrous chloride, copper chloride, nano zinc oxide, montmorillonite, and octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, preferably at least one of tetramethylthiuram disulfide, morpholino disulfide, ferrous chloride, and nano zinc oxide; And / or, the mass ratio of the primary stabilizer to the secondary stabilizer is 1:(2-5).

9. A method for preparing modified asphalt according to any one of claims 1-8, comprising: (1) Preparation of composite SBS modifier; (2) Mix a portion of the composite SBS modifier with a compatibilizer, and then shear and develop it for later use; (3) Heat the base asphalt to a molten state, mix it with the remaining composite SBS modifier, shear it, and then add the material prepared in step (2) and stir to develop. (4) Add a neutralizing slow-release stabilizer to the material obtained in step (3), and continue stirring to develop, to obtain modified asphalt.

10. The method according to claim 9, characterized in that, In step (1), the preparation process of the composite SBS modifier includes: putting the linear SBS modifier and the star-shaped SBS modifier into a grinding mill, shearing and grinding, and extruding and granulating to obtain the composite SBS modifier.

11. The method according to claim 9, characterized in that, In step (2), the amount of the partial composite SBS modifier is 30% to 70% of the total weight of the composite SBS modifier, preferably 40% to 65%; the shear rate is 3000 to 5000 r / min, preferably 3000 to 4500 r / min, the shearing time is 20 to 40 min, the temperature required for shearing is 120℃ to 145℃, preferably 125℃ to 135℃; the development temperature is 130℃ to 145℃, and the development time is 4h to 8h.

12. The method according to claim 9, characterized in that, In step (3), the heating temperature of the base asphalt is 130-145℃; the shearing and stirring development are both carried out under a protective gas, preferably an inert gas and / or N2; the shearing rate is 4000-6000 r / min, preferably 4000-5500 r / min, the shearing time is 60-80 min, and the temperature required for shearing is 170-185℃; the stirring speed is 600-800 r / min, the development time is 20-40 min, and the development temperature is 150℃-195℃, preferably 170℃-180℃.

13. The method according to claim 9, characterized in that, In step (4), the preparation method of the deodorizing sustained-release stabilizer includes: a: Mix cyclodextrin, surfactant and solvent, stir, then wash and freeze dry to obtain pretreated cyclodextrin; b: Mix the stabilizer and the deodorizing agent, stir, and obtain the core material mixture; c: Mix the core material mixture obtained in step b with the pretreated cyclodextrin and solvent obtained in step a, and stir. d: Add silica precursor to the reaction system in step c, stir to obtain Pickering emulsion, adjust pH, continue stirring, age, then filter, wash, freeze dry to obtain deodorizing sustained-release stabilizer.

14. The method according to claim 9, characterized in that, The surfactant mentioned in step a is a cationic surfactant, preferably one or more of dodecyl dimethyl benzyl ammonium chloride, hexadecyl trimethyl ammonium bromide, and octadecyl trimethyl ammonium chloride; And / or, the solvent is an aprotic solvent with a boiling point >100°C, preferably one or more of formamide, N,N-dimethylformamide, dimethylacetamide, and dimethylphosphoramide; And / or, the mass ratio of the cyclodextrin, solvent, and surfactant is (1-10):(10-50):

1.

15. The method according to claim 9, characterized in that, In step a, the stirring speed is 400-600 rpm; the stirring temperature is 100-200℃; and the stirring time is 4-10 hours. And / or, in step b, the stirring speed is 400-600 rpm, the stirring temperature is 30-70°C, and the stirring time is 3-10 minutes; And / or, in step c, the stirring speed is 400-600 rpm, the stirring temperature is 40-60°C, and the stirring time is 4-6 hours; And / or, in step d, the stirring conditions are each independently: the stirring speed is 400-600 rpm, the stirring temperature is 40-60°C, and the stirring time is 4-6 hours.

16. The method according to claim 9, characterized in that, In step c, the solvent is an aprotic solvent with a boiling point >100℃, preferably one or more of formamide, N,N-dimethylformamide, dimethylacetamide, and dimethylphosphoramide; And / or, in step c, the mass ratio of the core material mixture to the solvent pretreated cyclodextrin is (1-10):(20-60):

1.

17. The method according to claim 9, characterized in that, In step d, the silica precursor is a silicate compound, preferably one or more of methyl silicate, ethyl orthosilicate, tetraethyl orthosilicate, and butyl orthosilicate. And / or, in step d, the mass ratio of the reaction system to the silica precursor is (0.5-2):

1.

18. The use of the modified asphalt according to any one of claims 1-8 or the modified asphalt prepared by the method according to any one of claims 9-17 in a racetrack.

Images