Micron-sized asphalt modifier and preparation method thereof

Abstract

The invention discloses a micron-sized asphalt modifier and a preparation method thereof, the micron-sized asphalt modifier comprises the following substances in percentage by mass: 95-98 wt% of epoxidized SBS and N-phenylamino propyl POSS (Polyhedral Oligomeric Silsesquioxane), 1-3 wt% of a silane coupling agent, 0.5-2 wt% of an antioxidant and 0.1-0.3 wt% of a cross-linking agent, and the mass of the epoxidized SBS is 2-2.5 times that of the N-phenylamino propyl POSS. The preparation method comprises the following steps: preparing epoxidized SBS; the preparation method comprises the following steps: firstly, putting epoxidized SBS into an internal mixer for plasticizing, and then adding N-phenylaminopropyl POSS for mixing; a silane coupling agent, an antioxidant and a cross-linking agent are added into an internal mixer for continuous mixing to obtain an epoxidized SBS-POSS modifier material, and then the material is subjected to refining pretreatment. The high-temperature and low-temperature performance balance, long-acting aging resistance and excellent storage stability of the asphalt can be realized at the same time.

Description

Technical Field

[0001] This invention belongs to the field of asphalt modification technology in road engineering, specifically relating to a micron-sized asphalt modifier and its preparation method. Background Technology

[0002] As is well known, asphalt pavement has become a major construction material for roads worldwide due to its advantages such as driving comfort and ease of maintenance. However, with the continuous increase in traffic load and the increasingly deteriorating climate, the requirements for the comprehensive performance of asphalt materials are also becoming more stringent, and traditional asphalt materials are facing severe challenges.

[0003] While ordinary SBS modified asphalt is widely used, it is unable to resist permanent deformation caused by heavy vehicles, and asphalt pavements are prone to cracking in low-temperature environments (below 0°C). Although adding nano-inorganic fillers (such as montmorillonite) can improve the high-temperature stability of asphalt, this often exacerbates its low-temperature brittleness. In addition, because the butadiene segment in the SBS molecule contains a large number of unsaturated double bonds (accounting for 60-80%), it is prone to chain-breaking and cross-linking reactions under the action of ultraviolet light and oxygen, leading to asphalt hardening and embrittlement.

[0004] To overcome the aforementioned technical bottlenecks, existing technologies employ epoxidized SBS to modify asphalt. This technology introduces epoxy groups into the butadiene segment of SBS through an epoxidation reaction, thereby improving the compatibility between epoxidized SBS and asphalt. However, single epoxidation modification has limited effect on improving the high-temperature performance of asphalt and cannot effectively inhibit or delay asphalt aging.

[0005] Cage-type polysilsesquioxanes (POSS) can be used to improve the thermal stability of materials due to their nanoscale organic-inorganic hybrid structure. However, non-reactive POSS lacks active groups and is difficult to form chemical bonds with asphalt or polymers. When the addition amount exceeds 3 wt%, agglomeration occurs, leading to performance degradation. While some reactive POSS (such as epoxy-based POSS) can participate in cross-linking reactions, the lack of benzene rings results in insufficient UV shielding efficiency.

[0006] In contrast, aminophenyl POSS possesses both amino group reactivity and phenyl UV absorption function, theoretically capable of synergistically improving asphalt performance. However, its application in SBS-modified asphalt still faces two major technical challenges: (1) the reaction rate between the amino group and the epoxy group is too fast, resulting in excessive crosslinking and easy gelation; (2) the compatibility between POSS and the asphalt interface is poor, and the segregation problem has not been fundamentally solved. Therefore, it is urgent to develop a micron-sized asphalt modifier composed of epoxidized SBS and POSS and its preparation method to solve the problems existing in the current technology.

[0007] Patent application CN102964850A discloses an epoxidized SBS modified asphalt and its production process. The composition is 100 parts base asphalt and 2-7 parts epoxidized SBS. The preparation method of epoxidized SBS involves placing SBS and toluene in a reaction vessel, adding formic acid after the SBS is completely dissolved, stirring at 60-80℃, then adding hydrogen peroxide dropwise and reacting for 1-5 hours. Theoretically, this technology improves the compatibility of epoxidized SBS with asphalt; however, single epoxidation modification has limited effect on improving the high-temperature performance of asphalt and cannot effectively inhibit or delay asphalt aging.

[0008] Chinese patent application CN106398247A discloses an asphalt modifier and modified asphalt. The asphalt modifier includes polysilsesquioxanes with organic functional groups, specifically silanol polysilsesquioxanes, octavinyl polysilsesquioxanes, octaphenolic hydroxy polysilsesquioxanes, octaaminohydrochloride polysilsesquioxanes, phenyl polysilsesquioxanes, chloropropyl polysilsesquioxanes, fluorinated polysilsesquioxanes, or isobutyl methacrylate polysilsesquioxanes. This technical solution uses POSS as a modifier, which improves asphalt performance, but still suffers from poor interfacial compatibility between POSS and asphalt. Summary of the Invention

[0009] To address the problems existing in the prior art, this invention provides a micron-sized asphalt modifier, which is composed of epoxidized SBS and POSS. The micron-sized asphalt modifier is composed of epoxidized SBS, N-phenylaminopropyl POSS, a silane coupling agent, an antioxidant, and a crosslinking agent. The mass percentage of each substance in the micron-sized asphalt modifier is as follows: the sum of the mass of epoxidized SBS and N-phenylaminopropyl POSS accounts for 95-98 wt%, the silane coupling agent accounts for 1-3 wt%, the antioxidant accounts for 0.5-2 wt%, and the crosslinking agent accounts for 0.1-0.3 wt%. The mass of epoxidized SBS is 2-2.5 times the mass of N-phenylaminopropyl POSS, and the sum of the contents of all substances is 100 wt%.

[0010] Preferably, the epoxidized SBS is prepared from SBS through an epoxidation reaction, and its epoxy value ranges from 0.25 to 0.32 mol / 100g.

[0011] In any of the above embodiments, it is preferred that the silane coupling agent is of type KH570, KH560, or KH550. KH560 is more preferred.

[0012] In any of the above embodiments, the antioxidant is preferably pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0013] In any of the above embodiments, it is preferred that the crosslinking agent is dicumyl peroxide.

[0014] This invention also provides a method for preparing a micron-sized asphalt modifier, used to prepare the micron-sized asphalt modifier described in any of the above claims, comprising the following steps in sequence:

[0015] Step 1: Prepare epoxidized SBS according to the designed process parameters;

[0016] Step 2: Weigh out the epoxidized SBS, N-phenylaminopropyl POSS, silane coupling agent, antioxidant, and crosslinking agent according to the designed material ratio and set aside;

[0017] Step 3: First, heat the mixing chamber of the internal mixer to a certain temperature, then put the epoxidized SBS into the mixing chamber for plasticization; then add N-phenylaminopropyl POSS into the mixing chamber, and then raise the temperature in the mixing chamber to a certain temperature. At this temperature, the epoxidized SBS and N-phenylaminopropyl POSS are mixed and undergo a melt crosslinking reaction.

[0018] Step 4: Keep the temperature in the mixing chamber constant, add the silane coupling agent, antioxidant and crosslinking agent to the mixing chamber and continue mixing. After mixing is completed, the epoxidized SBS-POSS modifier material is obtained.

[0019] Step 5: The obtained epoxidized SBS-POSS modifier material is subjected to a fine pretreatment. After the fine pretreatment is completed, a micron-sized asphalt modifier composed of epoxidized SBS and POSS is obtained, with a particle size not exceeding 5μm.

[0020] Preferably, in step one, the preparation method of the epoxidized SBS includes the following steps in sequence:

[0021] Step 1.1: Place the cyclohexane solution into the reaction vessel and heat it to 55-65℃. Then add SBS into the reaction vessel and stir to completely dissolve the SBS, obtaining a reaction solution with a concentration of 10-15g / 100ml.

[0022] Step 1.2: Keep the temperature in the reaction vessel constant, add tetrabutylammonium bromide as a phase transfer catalyst and stir for 5-10 min. The amount of tetrabutylammonium bromide added is 0.2-0.25 wt% of the mass of SBS.

[0023] Step 1.3: Keep the temperature in the reaction vessel constant, add 88% formic acid and stir for 10-20 minutes. The amount of formic acid added is 5.5-6.5 wt% of the mass of SBS.

[0024] Step 1.4: Keep the temperature in the reaction vessel constant, and slowly add a 30% hydrogen peroxide aqueous solution at a rate of 1-2 drops / s. The amount of hydrogen peroxide aqueous solution added is 4.5-5.5 wt% of the mass of SBS.

[0025] Step 1.5: Raise the temperature in the reaction vessel by 5-10°C and control it within the range of 65-70°C. Carry out the SBS epoxidation reaction at this temperature for 4-5 hours.

[0026] Step 1.6: After the reaction is complete, precipitate with ethanol and wash several times. Then dry in a vacuum oven at 50-60℃ to constant weight to obtain epoxidized SBS.

[0027] In this invention, the epoxidation reaction structure of SBS (partial epoxidation) is as follows:

[0028]

[0029] In any of the above schemes, preferably, in step three, epoxidized SBS is placed in a mixing chamber for plasticization at a temperature of 155-165℃ for 5-8 min; N-phenylaminopropyl POSS is added to the mixing chamber, and the temperature in the mixing chamber is increased to 175-180℃ at a heating rate of 5-8℃ / min, and the mixing time of epoxidized SBS and N-phenylaminopropyl POSS is 20-25 min.

[0030] In this invention, a melt crosslinking reaction occurs between epoxidized SBS and N-phenylaminopropyl POSS, as detailed below:

[0031]

[0032] In any of the above schemes, it is preferred that, in step four, the silane coupling agent, antioxidant and crosslinking agent are added to the mixing chamber for mixing, the mixing temperature is 175-180℃ and the mixing time is 5-10 min.

[0033] In any of the above schemes, preferably, in step five, the refining pretreatment of the epoxidized SBS-POSS modifier material includes the following steps in sequence:

[0034] Step 5.1: Place the epoxidized SBS-POSS modifier material into a ball mill jar, add deionized water and zirconia grinding beads to the ball mill jar. The mass ratio of the epoxidized SBS-POSS modifier material to the zirconia grinding beads is 1:10, the mass ratio of the epoxidized SBS-POSS modifier material to the deionized water is 1:3, and the particle size of the zirconia grinding beads is 0.1 mm. Then, place the ball mill jar into a planetary ball mill for the first ball milling. The ball milling speed is 280-320 r / min, and the ball milling time is 2-4 h.

[0035] Step 5.2: After the first ball milling is completed, remove and separate the epoxidized SBS-POSS modifier material, deionized water and zirconium oxide milling beads from the ball milling jar, and then repeat the operation of step 5.1 to perform the second ball milling;

[0036] Step 5.3: After the second ball milling is completed, remove the epoxidized SBS-POSS modifier material from the ball mill jar and place it in a drying oven for drying treatment. The drying temperature is 100-110℃ and the drying time is 1-3 hours.

[0037] In this invention, the internal mixer, reaction vessel, stirrer, vacuum oven, ball mill jar, ball mill, drying oven, etc., used are all existing equipment. There are no special limitations on the equipment model or structure, as long as the process parameters meet the design requirements of this invention. In this invention, the Chinese name for SBS is styrene-butadiene-styrene block copolymer, and the Chinese name for POSS is cage-type polysilsesquioxane.

[0038] In the entire process of preparing the epoxidized SBS-POSS micron-sized asphalt modifier, the selection and proportion of each substance, the order of addition of each substance, and the process parameters of each step are all very critical. Only by synergistically combining the various formulation parameters and process parameters can the technical effect expected by this invention be achieved.

[0039] The various substances work synergistically to construct a three-in-one structure of "rigidity and flexibility, interfacial stability, and long-term protection." Epoxidized SBS and N-phenylaminopropyl POSS form a rigid-flexible interpenetrating network. The POSS cages, acting as nano-crosslinking points, restrict molecular chain movement, increase the high-temperature softening point, and enhance the material's rigidity. The un-epoxidized double bonds in SBS provide deformation capability, preserving the material's flexibility. The internal cavities of POSS can absorb small-molecule softening components, inhibiting low-temperature embrittlement. The silane coupling agent acts as a dual interfacial anchor, ensuring interfacial stability. The antioxidant and POSS phenyl groups work synergistically through chemical quenching and physical shielding, respectively, enhancing the material's anti-aging properties. In terms of the preparation process, the microstructure is precisely controlled through five steps, precisely controlling the epoxy value, crosslinking degree, material particle size, and dispersion stability.

[0040] The micron-sized asphalt modifier and its preparation method of the present invention have the following beneficial effects:

[0041] (1) The asphalt modifier prepared by the present invention is obtained by SBS epoxidation, cross-linking and curing of epoxidized SBS and N-phenylaminopropyl POSS, and fine pretreatment. The particle size is finally controlled below 5 μm. Compared with traditional SBS modifiers (the particle size is usually more than 10 μm), its particle size is reduced by at least 50%.

[0042] (2) The asphalt modifier prepared by the present invention has better dispersibility in asphalt, can reduce the occurrence of agglomeration, can significantly improve the road performance and thermal storage stability of modified asphalt, and can effectively inhibit or delay asphalt aging.

[0043] (3) The amino group (-NH2) of N-phenylaminopropyl POSS used in this invention reacts with the epoxy group of epoxidized SBS through a ring-opening addition reaction to form a covalent bond network of "rigid POSS cage-flexible SBS chain", which solves the problem of the contradiction between high and low temperature performance of asphalt. The POSS nanocage, as a crosslinking node, increases the softening point of asphalt, and the flexible double bond of the retained SBS butadiene segment ensures the ductility of asphalt.

[0044] (4) The N-phenylaminopropyl POSS used in this invention can enhance the thermal stability of asphalt by means of its nanoscale organic-inorganic hybrid structure. Its phenyl group can absorb ultraviolet light and work together with antioxidants to quench free radicals, thus achieving long-term anti-aging of asphalt.

[0045] (5) The technical solution of the present invention can simultaneously achieve a balance between high and low temperature performance of asphalt, long-term anti-aging and excellent storage stability, while avoiding the problems of excessive reaction speed and excessive cross-linking, thus filling the technical gap in the industry. Attached Figure Description

[0046] Figure 1 This is a process flow diagram of a preferred embodiment of the micron-sized asphalt modifier and its preparation method according to the present invention;

[0047] Figure 2 for Figure 1 A photograph of the micron-sized asphalt modifier prepared in the illustrated embodiment;

[0048] Figure 3 The results of DSR tests on five types of undisturbed asphalt are shown.

[0049] Figure 4 The results of DSR tests on five types of aged asphalt;

[0050] Figure 5 The results of the stiffness modulus tests for five types of asphalt;

[0051] Figure 6The results are from the stiffness change rate test of five types of asphalt. Detailed Implementation

[0052] To further understand the invention, the following detailed description of the invention will be provided in conjunction with specific embodiments.

[0053] Example 1:

[0054] According to a preferred embodiment of the micron-sized asphalt modifier of the present invention, it is composed of epoxidized SBS and POSS. The micron-sized asphalt modifier is composed of epoxidized SBS, N-phenylaminopropyl POSS, silane coupling agent, antioxidant, and crosslinking agent. The mass percentage of each substance in the micron-sized asphalt modifier is as follows: the sum of the mass of epoxidized SBS and N-phenylaminopropyl POSS accounts for 96.5 wt%, the silane coupling agent accounts for 2 wt%, the antioxidant accounts for 1.3 wt%, and the crosslinking agent accounts for 0.2 wt%. The mass of epoxidized SBS is 2.2 times the mass of N-phenylaminopropyl POSS, and the sum of the contents of each substance is 100 wt%.

[0055] The epoxidized SBS is prepared by epoxidation of SBS, and its epoxy value is controlled within the range of 0.25-0.32 mol / 100g; the preferred type of the silane coupling agent is KH560; the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; and the crosslinking agent is dicumyl peroxide.

[0056] like Figure 1 As shown, this embodiment also provides a method for preparing a micron-sized asphalt modifier, which includes the following steps in sequence:

[0057] Step 1: Prepare epoxidized SBS according to the designed process parameters;

[0058] Step 2: Weigh out the epoxidized SBS, N-phenylaminopropyl POSS, silane coupling agent, antioxidant, and crosslinking agent according to the designed material ratio and set aside;

[0059] Step 3: First, heat the mixing chamber of the internal mixer to a certain temperature, then put the epoxidized SBS into the mixing chamber for plasticization; then add N-phenylaminopropyl POSS into the mixing chamber, and then raise the temperature in the mixing chamber to a certain temperature. At this temperature, the epoxidized SBS and N-phenylaminopropyl POSS are mixed and undergo a melt crosslinking reaction.

[0060] Step 4: Keep the temperature in the mixing chamber constant, add the silane coupling agent, antioxidant and crosslinking agent to the mixing chamber and continue mixing. After mixing is completed, the epoxidized SBS-POSS modifier material is obtained.

[0061] Step 5: The obtained epoxidized SBS-POSS modifier material is subjected to a fine pretreatment. After the fine pretreatment is completed, a micron-sized asphalt modifier composed of epoxidized SBS and POSS is obtained, with a particle size not exceeding 5μm.

[0062] In step one, the preparation method of the epoxidized SBS includes the following steps in sequence:

[0063] Step 1.1: Place the cyclohexane solution into the reaction vessel and heat it to 60°C. Then add SBS into the reaction vessel and stir until the SBS is completely dissolved to obtain a reaction solution with a concentration of 12g / 100ml.

[0064] Step 1.2: Keep the temperature in the reaction vessel constant, add tetrabutylammonium bromide as a phase transfer catalyst and stir for 8 minutes. The amount of tetrabutylammonium bromide added is 0.23 wt% of the mass of SBS.

[0065] Step 1.3: Keep the temperature in the reaction vessel constant, add 88% formic acid and stir for 15 minutes. The amount of formic acid added is 6 wt% of the mass of SBS.

[0066] Step 1.4: Keep the temperature in the reaction vessel constant, and slowly add a 30% hydrogen peroxide aqueous solution at a rate of 2 drops / s. The amount of hydrogen peroxide aqueous solution added is 5 wt% of the mass of SBS.

[0067] Step 1.5: Raise the temperature in the reaction vessel by 8°C, i.e. 68°C, and ensure that it is controlled within the range of 65-70°C. Carry out the SBS epoxidation reaction at this temperature for 4.5 hours.

[0068] Step 1.6: After the reaction is complete, precipitate with ethanol and wash several times. Then dry in a vacuum oven at 55°C to constant weight to obtain epoxidized SBS.

[0069] In this embodiment, the epoxidation reaction structure of SBS (partial epoxidation) is as follows:

[0070]

[0071] In step three, epoxidized SBS is placed in a mixing chamber for plasticization at a temperature of 160°C for 6.5 min. N-phenylaminopropyl POSS is then added to the mixing chamber, and the temperature in the mixing chamber is increased to 178°C at a rate of 6.5°C / min. The mixing time of epoxidized SBS and N-phenylaminopropyl POSS is 22 min.

[0072] In this embodiment, a melt crosslinking reaction occurs between epoxidized SBS and N-phenylaminopropyl POSS, as detailed below:

[0073]

[0074] In step four, the silane coupling agent, antioxidant, and crosslinking agent are added to the mixing chamber for mixing at a temperature of 178°C for 8 minutes.

[0075] In step five, the refining pretreatment of the epoxidized SBS-POSS modifier material includes the following steps in sequence:

[0076] Step 5.1: Place the epoxidized SBS-POSS modifier material into a ball mill jar, add deionized water and zirconia grinding beads to the ball mill jar. The mass ratio of the epoxidized SBS-POSS modifier material to the zirconia grinding beads is 1:10, the mass ratio of the epoxidized SBS-POSS modifier material to the deionized water is 1:3, and the particle size of the zirconia grinding beads is 0.1 mm. Then, place the ball mill jar into a planetary ball mill for the first ball milling. The ball milling speed is 300 r / min, and the ball milling time is 3 h.

[0077] Step 5.2: After the first ball milling is completed, remove and separate the epoxidized SBS-POSS modifier material, deionized water and zirconium oxide milling beads from the ball milling jar, and then repeat the operation of step 5.1 to perform the second ball milling;

[0078] Step 5.3: After the second ball milling is completed, remove the epoxidized SBS-POSS modifier material from the ball mill jar and place it in a drying oven for drying treatment. The drying temperature is 105℃ and the drying time is 2 hours.

[0079] In this embodiment, the selection and proportioning of each substance, the order of addition of each substance, and the process parameters of each step are all crucial in the entire process of preparing the epoxidized SBS-POSS micron-sized asphalt modifier. Only by synergistically combining the various formulation and process parameters can the expected technical effect of this embodiment be achieved. The epoxidized SBS-POSS micron-sized asphalt modifier prepared in this embodiment is as follows: Figure 2 As shown.

[0080] The micron-sized asphalt modifier and its preparation method in this embodiment have the following beneficial effects: (1) The prepared asphalt modifier is obtained by SBS epoxidation, cross-linking and curing of epoxidized SBS and N-phenylaminopropyl POSS, and fine pretreatment. The final particle size is controlled below 5μm, which is at least 50% smaller than that of traditional SBS modifier. (2) The prepared asphalt modifier has better dispersibility in asphalt, which can reduce the occurrence of agglomeration, significantly improve the road performance and thermal storage stability of modified asphalt, and effectively inhibit or delay asphalt aging. (3) The amino group (-NH2) of N-phenylaminopropyl POSS and the epoxy group of epoxidized SBS form a covalent bond network of "rigid POSS cage-flexible SBS chain" through ring-opening addition reaction, which solves the problem of the contradiction between high and low temperature performance of asphalt. The POSS nanocage, as a cross-linking node, increases the softening point of asphalt. The remaining flexible double bond of some SBS butadiene segments ensures the ductility of asphalt. (4) The N-phenylaminopropyl POSS used can enhance the thermal stability of asphalt by means of its nanoscale organic-inorganic hybrid structure. Its phenyl group can absorb ultraviolet light and work together with antioxidants to quench free radicals, thus achieving long-term anti-aging of asphalt.

[0081] Example 2:

[0082] According to another preferred embodiment of the micron-sized asphalt modifier and its preparation method of the present invention, the material selection, material ratio, preparation process, reaction principle, and beneficial effects are basically the same as those in Example 1, except that:

[0083] The micron-sized asphalt modifier is composed of epoxidized SBS, N-phenylaminopropyl POSS, silane coupling agent, antioxidant, and crosslinking agent. The mass percentage of each substance in the micron-sized asphalt modifier is as follows: the sum of the masses of epoxidized SBS and N-phenylaminopropyl POSS accounts for 95 wt%, the silane coupling agent accounts for 3 wt%, the antioxidant accounts for 1.9 wt%, and the crosslinking agent accounts for 0.1 wt%. The mass of epoxidized SBS is twice the mass of N-phenylaminopropyl POSS, and the sum of the contents of all substances is 100 wt%.

[0084] In step one, the preparation method of the epoxidized SBS includes the following steps in sequence:

[0085] Step 1.1: Place the cyclohexane solution into the reaction vessel and heat it to 55°C. Then add SBS into the reaction vessel and stir until the SBS is completely dissolved to obtain a reaction solution with a concentration of 10g / 100ml.

[0086] Step 1.2: Keep the temperature in the reaction vessel constant, add tetrabutylammonium bromide as a phase transfer catalyst and stir for 5 minutes. The amount of tetrabutylammonium bromide added is 0.2 wt% of the mass of SBS.

[0087] Step 1.3: Keep the temperature in the reaction vessel constant, add 88% formic acid and stir for 10 minutes. The amount of formic acid added is 5.5 wt% of the mass of SBS.

[0088] Step 1.4: Keep the temperature in the reaction vessel constant, and slowly add a 30% hydrogen peroxide aqueous solution at a dropping rate of 1 drop / s. The amount of hydrogen peroxide aqueous solution added is 4.5 wt% of the mass of SBS.

[0089] Step 1.5: Raise the temperature in the reaction vessel by 10°C, i.e. 65°C, and ensure that it is controlled within the range of 65-70°C. Carry out the SBS epoxidation reaction at this temperature for 4 hours.

[0090] Step 1.6: After the reaction is complete, precipitate with ethanol and wash several times. Then dry in a vacuum oven at 50°C to constant weight to obtain epoxidized SBS.

[0091] In step three, epoxidized SBS is placed in a mixing chamber for plasticization at a temperature of 155°C for 8 minutes. N-phenylaminopropyl POSS is then added to the mixing chamber, and the temperature in the mixing chamber is increased to 175°C at a rate of 5°C / min. The mixing time of epoxidized SBS and N-phenylaminopropyl POSS is 25 minutes.

[0092] In step four, the silane coupling agent, antioxidant, and crosslinking agent are added to the mixing chamber for mixing at a temperature of 175°C for 10 minutes.

[0093] In step five, the refining pretreatment of the epoxidized SBS-POSS modifier material includes the following steps in sequence:

[0094] Step 5.1: Place the epoxidized SBS-POSS modifier material into a ball mill jar, add deionized water and zirconia grinding beads to the ball mill jar. The mass ratio of the epoxidized SBS-POSS modifier material to the zirconia grinding beads is 1:10, the mass ratio of the epoxidized SBS-POSS modifier material to the deionized water is 1:3, and the particle size of the zirconia grinding beads is 0.1 mm. Then, place the ball mill jar into a planetary ball mill for the first ball milling. The ball milling speed is 280 r / min, and the ball milling time is 4 h.

[0095] Step 5.2: After the first ball milling is completed, remove and separate the epoxidized SBS-POSS modifier material, deionized water and zirconium oxide milling beads from the ball milling jar, and then repeat the operation of step 5.1 to perform the second ball milling;

[0096] Step 5.3: After the second ball milling is completed, remove the epoxidized SBS-POSS modifier material from the ball mill jar and place it in a drying oven for drying treatment at 100℃ for 3 hours.

[0097] Example 3:

[0098] According to another preferred embodiment of the micron-sized asphalt modifier and its preparation method of the present invention, the material selection, material ratio, preparation process, reaction principle, and beneficial effects are basically the same as those in Example 1, except that:

[0099] The micron-sized asphalt modifier is composed of epoxidized SBS, N-phenylaminopropyl POSS, silane coupling agent, antioxidant, and crosslinking agent. The mass percentage of each substance in the micron-sized asphalt modifier is as follows: the sum of the masses of epoxidized SBS and N-phenylaminopropyl POSS accounts for 98 wt%, the silane coupling agent accounts for 1 wt%, the antioxidant accounts for 0.7 wt%, and the crosslinking agent accounts for 0.3 wt%. The mass of epoxidized SBS is 2.5 times the mass of N-phenylaminopropyl POSS, and the sum of the contents of all substances is 100 wt%.

[0100] In step one, the preparation method of the epoxidized SBS includes the following steps in sequence:

[0101] Step 1.1: Place the cyclohexane solution into the reaction vessel and heat it to 65°C. Then add SBS into the reaction vessel and stir until the SBS is completely dissolved to obtain a reaction solution with a concentration of 15g / 100ml.

[0102] Step 1.2: Keep the temperature in the reaction vessel constant, add tetrabutylammonium bromide as a phase transfer catalyst and stir for 10 min. The amount of tetrabutylammonium bromide added is 0.25 wt% of the mass of SBS.

[0103] Step 1.3: Keep the temperature in the reaction vessel constant, add 88% formic acid and stir for 20 minutes. The amount of formic acid added is 6.5 wt% of the mass of SBS.

[0104] Step 1.4: Keep the temperature in the reaction vessel constant, and slowly add a 30% hydrogen peroxide aqueous solution at a rate of 2 drops / s. The amount of hydrogen peroxide aqueous solution added is 5.5 wt% of the mass of SBS.

[0105] Step 1.5: Raise the temperature in the reaction vessel by 5°C, i.e. 70°C, and ensure that it is controlled within the range of 65-70°C. Carry out the SBS epoxidation reaction at this temperature for 5 hours.

[0106] Step 1.6: After the reaction is complete, precipitate with ethanol and wash several times. Then dry in a vacuum oven at 60°C to constant weight to obtain epoxidized SBS.

[0107] In step three, epoxidized SBS is placed in a mixing chamber for plasticization at a temperature of 165°C for 5 minutes. N-phenylaminopropyl POSS is then added to the mixing chamber, and the temperature in the mixing chamber is increased to 180°C at a rate of 8°C / min. The mixing time of epoxidized SBS and N-phenylaminopropyl POSS is 20 minutes.

[0108] In step four, the silane coupling agent, antioxidant, and crosslinking agent are added to the mixing chamber for mixing at a temperature of 180°C for 5 minutes.

[0109] In step five, the refining pretreatment of the epoxidized SBS-POSS modifier material includes the following steps in sequence:

[0110] Step 5.1: Place the epoxidized SBS-POSS modifier material into a ball mill jar, add deionized water and zirconia grinding beads to the ball mill jar. The mass ratio of the epoxidized SBS-POSS modifier material to the zirconia grinding beads is 1:10, the mass ratio of the epoxidized SBS-POSS modifier material to the deionized water is 1:3, and the particle size of the zirconia grinding beads is 0.1 mm. Then, place the ball mill jar into a planetary ball mill for the first ball milling. The ball milling speed is 320 r / min, and the ball milling time is 2 h.

[0111] Step 5.2: After the first ball milling is completed, remove and separate the epoxidized SBS-POSS modifier material, deionized water and zirconium oxide milling beads from the ball milling jar, and then repeat the operation of step 5.1 to perform the second ball milling;

[0112] Step 5.3: After the second ball milling is completed, remove the epoxidized SBS-POSS modifier material from the ball mill jar and place it in a drying oven for drying treatment. The drying temperature is 110℃ and the drying time is 1 hour.

[0113] The micron-sized asphalt modifier prepared by the above three embodiments was used to further prepare modified asphalt. Then, the performance of the prepared modified asphalt and SBS modified asphalt was tested. The test equipment, test environment, test conditions, sample shape and size were all the same. Three sets of parallel tests were performed for each performance test, and then the average value was taken.

[0114] I. Key Performance Tests of Asphalt

[0115] Modified asphalt was prepared using the micron-sized asphalt modifier obtained from the examples, and compared with ordinary SBS modified asphalt to study the influence of different modifiers on the key properties of asphalt. 6%, 9%, and 12% of SBS modifier and the micron-sized modifier obtained from the examples were added to No. 70 base asphalt, respectively, and the performance of the modified asphalt was tested. The specific test results are shown in Table 1. The influence of the micron-sized modifier on the three major properties of the modified asphalt shows that the incorporation of the micron-sized modifier increases the penetration and ductility of the modified asphalt, and decreases the softening point.

[0116] Table 1. Test results of key properties of modified asphalt after adding SBS modifier and micron-sized modifier.

[0117] Test number Modifier addition amount (%) 25℃ penetration (0.1mm) Softening point (°C) Ductility at 5℃ (cm) SBS modified asphalt 6 44.3 99.2 41.6 Modified asphalt in Example 1 6 54.9 91.2 47.6 Modified asphalt in Example 2 6 55.7 89.1 49.1 Modified asphalt in Example 3 6 55.1 88.9 48.8 SBS modified asphalt 9 41.1 110.8 63.9 Modified asphalt in Example 1 9 62.3 104.7 70.2 Modified asphalt in Example 2 9 64.8 102.9 71.9 Modified asphalt in Example 3 9 63.4 103.7 72.8 SBS modified asphalt 12 38.9 122.3 68.6 Modified asphalt in Example 1 12 64.6 112.0 73.2 Modified asphalt in Example 2 12 64.9 110.8 75.1 Modified asphalt in Example 3 12 65.5 111.6 74.6

[0118] II. Rheological property testing of asphalt

[0119] Taking Example 1 as an example, the effects of different modifiers and their dosages on the rheological properties of asphalt were studied. The SBS addition amount was 6%, and the addition amounts of the micron-sized modifiers prepared in Example 1 were 6%, 9%, and 12%, respectively. The modified asphalts prepared were named RMA1, RMA2, and RMA3, respectively.

[0120] (1) High-temperature performance test

[0121] Because asphalt is a temperature-sensitive material, its viscoelastic properties change significantly with increasing or decreasing temperature. At high temperatures, the complex shear modulus G* of asphalt decreases, while the phase angle δ increases. Under the same complex shear modulus G*, a larger phase angle δ indicates a greater proportion of viscous components that cannot be recovered under load, making it more prone to permanent deformation. A larger rutting resistance factor G* / sinδ indicates less flow deformation of the asphalt at high temperatures and stronger resistance to rutting. The SHRP specification stipulates that virgin asphalt should have a G* / sinδ ≥ 1.0 kPa, and RTFOT residual asphalt should have a G* / sinδ ≥ 2.2 kPa. Dynamic shear rheology (DSR) tests were conducted on five types of asphalt (SK base asphalt, SBS modified asphalt, RMA1, RMA2, and RMA3). Parallel plates with a diameter of 25 mm and a sample thickness of 1 mm were used. Dynamic shear was performed at a fixed angular rate of 10 rad / s. Based on the softening point test results, the corresponding initial test temperature was determined. The DSR test results of the undisturbed asphalt samples are shown below. Figure 3 As shown, the DSR test results of aged asphalt are as follows: Figure 4 As shown.

[0122] The test results show that as the content of micron-level modifier increases, the high temperature grade of modified asphalt continuously increases. When the content of micron-level modifier reaches a certain critical value, the high temperature performance of modified asphalt will be significantly improved, among which RMA3 has the best high temperature performance.

[0123] (2) Low temperature performance test

[0124] The SHRP asphalt technical specification proposes using the flexural beam rheological test (BBR) to evaluate the rheological and stress relaxation characteristics of asphalt binders under low temperature and constant load pressure. The test yields the stiffness modulus S and m values ​​of the asphalt. The stiffness modulus S characterizes the asphalt's resistance to permanent deformation, while the m value characterizes the rate of change of asphalt stiffness under load. SHRP research suggests that under low temperature conditions, if the flexural creep stiffness modulus S of the asphalt is large and the m value is small, the pavement is prone to low-temperature cracking. Therefore, the S value is required to not exceed 300 MPa, and the m value should not be less than 0.3. Low-temperature flexural creep tests were conducted on five types of asphalt (SK base asphalt, SBS modified asphalt, RMA1, RMA2, and RMA3) using a BBR testing instrument. The test results of the stiffness modulus for different asphalts are as follows: Figure 5 As shown in the figure, the test results of the stiffness change rate of different asphalts are as follows: Figure 6 As shown.

[0125] The test results show that the base asphalt, SBS modified asphalt, RMA1 modified asphalt, RMA2 modified asphalt, and RMA3 modified asphalt failed the tests at temperatures of -24℃, -24℃, -24℃, -36℃, and -36℃, respectively, because the flexural creep stiffness modulus S value was greater than 300MPa or the m value was less than 0.3. The RMA2 and RMA3 modified asphalts showed the same failure temperature, and were the lowest, indicating that the addition of micron-level modifiers can significantly improve the low-temperature performance of asphalt. However, after a certain dosage, the failure temperature of the asphalt BBR test will no longer decrease with further increases in modifier dosage.

[0126] The SBS, silane coupling agent, antioxidant, crosslinking agent, etc. used in the above embodiments were purchased from Beijing Municipal Road and Bridge Building Materials Group Co., Ltd., the cyclohexane solution, tetrabutylammonium bromide, formic acid, hydrogen peroxide, ethanol, etc. were purchased from Aladdin Reagent Co., Ltd., and N-phenylaminopropyl POSS was purchased from Hybrid Plastics, Inc., model AM0281 (pure state).

[0127] Special Note: The technical solution of this invention involves numerous parameters, and the synergistic effects between these parameters must be comprehensively considered to achieve the beneficial effects and significant progress of this invention. Furthermore, the value ranges of each parameter in the technical solution were obtained through extensive experimentation. For each parameter and the combinations thereof, the inventors have recorded a large amount of experimental data; however, due to space limitations, the specific experimental data is not disclosed here.

[0128] It will be readily understood by those skilled in the art that this invention includes any combination of the inventive description and specific embodiments outlined in the foregoing specification and the various parts shown in the accompanying drawings. Due to space limitations and for the sake of brevity, not all of these combinations have been described in detail. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A micron-sized asphalt modifier, characterized in that: The micron-sized asphalt modifier is composed of epoxidized SBS and POSS. It comprises epoxidized SBS, N-phenylaminopropyl POSS, a silane coupling agent, an antioxidant, and a crosslinking agent. The mass percentage of each substance in the micron-sized asphalt modifier is as follows: the sum of the masses of epoxidized SBS and N-phenylaminopropyl POSS is 95-98 wt%, the silane coupling agent is 1-3 wt%, the antioxidant is 0.5-2 wt%, and the crosslinking agent is 0.1-0.3 wt%. The mass of epoxidized SBS is 2-2.5 times the mass of N-phenylaminopropyl POSS, and the sum of the contents of all substances is 100 wt%.

2. The micron-sized asphalt modifier according to claim 1, characterized in that: The epoxidized SBS is prepared by epoxidation of SBS, and its epoxy value ranges from 0.25 to 0.32 mol / 100g.

3. The micron-sized asphalt modifier according to claim 2, characterized in that: The silane coupling agent is of type KH570, KH560 or KH550.

4. The micron-sized asphalt modifier according to claim 3, characterized in that: The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid].

5. The micron-sized asphalt modifier according to claim 4, characterized in that: The crosslinking agent is dicumyl peroxide.

6. A method for preparing a micron-sized asphalt modifier, characterized in that: The preparation of the micron-sized asphalt modifier according to any one of claims 1-5 comprises the following steps in sequence. Step 1: Prepare epoxidized SBS according to the designed process parameters; Step 2: Weigh out the epoxidized SBS, N-phenylaminopropyl POSS, silane coupling agent, antioxidant, and crosslinking agent according to the designed material ratio and set aside; Step 3: First, heat the mixing chamber of the internal mixer to a certain temperature, then put the epoxidized SBS into the mixing chamber for plasticization; then add N-phenylaminopropyl POSS into the mixing chamber, and then raise the temperature in the mixing chamber to a certain temperature. At this temperature, the epoxidized SBS and N-phenylaminopropyl POSS are mixed and undergo a melt crosslinking reaction. Step 4: Keep the temperature in the mixing chamber constant, add the silane coupling agent, antioxidant and crosslinking agent to the mixing chamber and continue mixing. After mixing is completed, the epoxidized SBS-POSS modifier material is obtained. Step 5: The obtained epoxidized SBS-POSS modifier material is subjected to a fine pretreatment. After the fine pretreatment is completed, a micron-sized asphalt modifier composed of epoxidized SBS and POSS is obtained, with a particle size not exceeding 5μm.

7. The method for preparing the micron-sized asphalt modifier according to claim 6, characterized in that: In step one, the preparation method of the epoxidized SBS includes the following steps in sequence: Step 1.1: Place the cyclohexane solution into the reaction vessel and heat it to 55-65℃. Then add SBS into the reaction vessel and stir to completely dissolve the SBS, obtaining a reaction solution with a concentration of 10-15g / 100ml. Step 1.2: Keep the temperature in the reaction vessel constant, add tetrabutylammonium bromide as a phase transfer catalyst and stir for 5-10 min. The amount of tetrabutylammonium bromide added is 0.2-0.25 wt% of the mass of SBS. Step 1.3: Keep the temperature in the reaction vessel constant, add 88% formic acid and stir for 10-20 minutes. The amount of formic acid added is 5.5-6.5 wt% of the mass of SBS. Step 1.4: Keep the temperature in the reaction vessel constant, and slowly add a 30% hydrogen peroxide aqueous solution at a rate of 1-2 drops / s. The amount of hydrogen peroxide aqueous solution added is 4.5-5.5 wt% of the mass of SBS. Step 1.5: Raise the temperature in the reaction vessel by 5-10°C and control it within the range of 65-70°C. Carry out the SBS epoxidation reaction at this temperature for 4-5 hours. Step 1.6: After the reaction is complete, precipitate with ethanol and wash several times. Then dry in a vacuum oven at 50-60℃ to constant weight to obtain epoxidized SBS.

8. The method for preparing the micron-sized asphalt modifier according to claim 7, characterized in that: In step three, epoxidized SBS is placed in a mixing chamber for plasticization at a temperature of 155-165℃ for 5-8 minutes. N-phenylaminopropyl POSS is then added to the mixing chamber, and the temperature in the mixing chamber is increased to 175-180℃ at a rate of 5-8℃ / min. The mixing time of epoxidized SBS and N-phenylaminopropyl POSS is 20-25 minutes.

9. The method for preparing the micron-sized asphalt modifier according to claim 8, characterized in that: In step four, the silane coupling agent, antioxidant, and crosslinking agent are added to the mixing chamber for mixing at a temperature of 175-180℃ for 5-10 minutes.

10. The method for preparing the micron-sized asphalt modifier according to claim 9, characterized in that: In step five, the refining pretreatment of the epoxidized SBS-POSS modifier material includes the following steps in sequence: Step 5.1: Place the epoxidized SBS-POSS modifier material into a ball mill jar, add deionized water and zirconia grinding beads to the ball mill jar. The mass ratio of the epoxidized SBS-POSS modifier material to the zirconia grinding beads is 1:10, the mass ratio of the epoxidized SBS-POSS modifier material to the deionized water is 1:3, and the particle size of the zirconia grinding beads is 0.1 mm. Then, place the ball mill jar into a planetary ball mill for the first ball milling. The ball milling speed is 280-320 r / min, and the ball milling time is 2-4 h. Step 5.2: After the first ball milling is completed, remove and separate the epoxidized SBS-POSS modifier material, deionized water and zirconium oxide milling beads from the ball milling jar, and then repeat the operation of step 5.1 to perform the second ball milling; Step 5.3: After the second ball milling is completed, remove the epoxidized SBS-POSS modifier material from the ball mill jar and place it in a drying oven for drying treatment. The drying temperature is 100-110℃ and the drying time is 1-3 hours.

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