Asphalt modifier and modified colored asphalt

Abstract

The application relates to a kind of asphalt modifier and modified color asphalt, and belongs to the technical field of compound for asphalt modification.Nano material surface has higher active group, and easy to occur self-aggregation, so that nano material is difficult to realize complete dispersion in asphalt, which influences the low-temperature performance of modified asphalt.The application uses nano silicon dioxide which is sequentially surface modified by strong alkali solution, surfactant solution, hydrolysis solution of silane coupling agent and stearic acid solution.The nano silicon dioxide surface is sequentially modified in roughness, surface activity and organicity, which significantly improves the dispersibility of inorganic nano modifier in asphalt, avoids nano particle aggregation, limits high-temperature fluidity, and improves the high and low temperature performance of color asphalt.

Description

Technical Field

[0001] An asphalt modifier and modified colored asphalt belong to the technical field of compounds for asphalt modification. Background Technology

[0002] Colored asphalt is a binder with properties similar to petroleum asphalt, prepared from base oil, petroleum resin, and modifiers. Due to the relatively high amount of low-viscosity base oil added, colored asphalt exhibits poor high-temperature performance, necessitating the use of additives to improve its high-temperature properties. Nanomaterials, due to their unique properties, can significantly improve the high-temperature performance of modified asphalt when added to it; therefore, nanomaterials are widely used as modifiers in the modified asphalt field.

[0003] The modification effect of nanomaterials is closely related to their dispersibility in the modified system. As inorganic materials, they have poor compatibility in asphalt, resulting in poor low-temperature performance of the modified asphalt and adversely affecting its low-temperature properties. This is because nanomaterials have highly active groups on their surface, making them prone to self-aggregation. This makes it difficult to achieve complete dispersion of nanomaterials in asphalt. Furthermore, the agglomeration points formed by this aggregation are prone to brittle fracture under low temperatures and external forces, affecting the low-temperature performance of the modified asphalt. This agglomeration also causes a significant increase in the viscosity of the prepared asphalt.

[0004] Patent CN116120838A discloses a root-penetration resistant waterproof coating, its preparation, and its application. It discloses the use of a silane coupling agent to modify the surface silica filler. However, this primarily addresses the seepage prevention or low-temperature spraying properties of asphalt, failing to effectively solve the problem of low-temperature brittleness in asphalt caused by the agglomeration of the modifier. Patent CN202011258669.2 discloses a colored asphalt and its preparation method, which uses an alkali to modify the silica surface. However, the inventors found that after modifying the silica surface with an alkali, the increased surface roughness and activity made it more prone to agglomeration, leading to a decrease in the low-temperature performance of the asphalt. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an asphalt modifier and modified colored asphalt with good dispersion performance in asphalt.

[0006] The technical solution adopted by the present invention to solve its technical problem is: an asphalt modifier, characterized in that: it comprises nano-silica that has been surface modified sequentially by a strong alkaline solution, a surfactant solution, a hydrolysis solution of a silane coupling agent, and a stearic acid solution.

[0007] Preferably, the surfactant is one or both of sodium alkylbenzene sulfonate and alkyl sulfonate. These are anionic emulsifiers that can be rapidly hydrolyzed under alkaline conditions and are readily soluble in water, facilitating cleaning and reducing subsequent processing steps.

[0008] Preferably, the silane coupling agent is one or both of KH550 and KH570.

[0009] This invention reduces the number of high-energy active groups on the surface of nano-silica by surface modification treatment. Sodium hydroxide is used to treat the surface of nano-silica, increasing its roughness and thus its surface area, expanding the contact area with the silane coupling agent, which is beneficial for the complete progress of the subsequent grafting reaction. A surfactant is used; when sodium hydroxide is added to the nano-silica treated with sodium hydroxide, the sodium hydroxide adsorbed on the nano-silica surface dissolves in the surfactant solution, adjusting the pH of the surfactant solution to alkaline. At this point, the emulsifying and dispersing properties of the surfactant are released, promoting the uniform dispersion of the nano-silica particles. Simultaneously, the surfactant adsorbed on the nano-silica surface becomes charged due to hydrolysis under alkaline conditions, increasing the mutual repulsion between the nano-silica particles and preventing their aggregation.

[0010] Secondly, the uniformly dispersed nano-silica particle solution is mixed with a silane coupling agent hydrolysis solution. The organic groups generated after the hydrolysis of the silane coupling agent undergo a grafting reaction with the active groups on the surface of the nano-silica particles, reducing the content of active groups on the nano-silica surface, lowering the surface energy of the nano-silica particles, and preventing the agglomeration of the nano-silica particles. At the same time, the inorganic nano-silica particle surface is organically modified through the grafting reaction, which can increase the compatibility between the nano-silica particles and petroleum resin.

[0011] Finally, long-chain stearic acid was used to perform composite modification on the silane-modified nano-silica particles. The long-chain stearic acid underwent a secondary grafting reaction with the organic groups grafted onto the nano-silica particles, increasing the length of the organic branches and the steric hindrance between the nano-silica particles, further preventing the aggregation of the nano-silica particles. In addition, stearic acid can further react with the unreacted active groups on the surface of the nano-silica particles, further reducing the surface energy of the nano-silica particles and preventing their aggregation.

[0012] Preferably, the surface modification includes the following steps:

[0013] 1) After heating a strong alkaline solution to 50~70℃, it is mixed with nano-silica powder for surface modification, and then filtered to obtain filter residue;

[0014] 2) Heat the surfactant solution to 50~70℃ and mix it with the filter residue obtained in step 1) for 30~60 minutes to obtain a suspension;

[0015] 3) The hydrolysis solution of the silane coupling agent is heated to 70~80℃ and the suspension obtained in step 2) is added. The reaction is carried out for 150~200 min. The product is centrifuged, washed and dried to obtain a solid. Preferably, the drying temperature is 80℃ and the drying time is 60~80 min.

[0016] 4) The stearic acid solution and the solid obtained in step 3) are reacted at 60~80℃ for 180~240 min, centrifuged, washed and dried to obtain modified nano-silica.

[0017] Preferably, the strong alkaline solution is obtained by mixing sodium hydroxide and water at a weight ratio of 0.1 to 0.5:1.

[0018] Stirring at 50~70℃ and 100~200rpm for 10~20min can accelerate the dissolution rate of sodium hydroxide in water. At the same time, within this concentration range, it ensures that the nano-SiO2 reacts fully, and also ensures that the reaction is not insufficient due to too low a concentration of strong alkali solution or excessive due to too high a concentration.

[0019] Preferably, the surfactant solution is obtained by mixing water and surfactant at a weight ratio of 94~95:5.

[0020] Preferably, the surfactant solution is obtained by mixing water, surfactant, and thickener at a weight ratio of 94-95:5:0.05-0.1, and mixing at 300-500 rpm for 60-80 minutes. The preferred mixing speed is 300-500 rpm for 60-80 minutes. The thickener first absorbs water and swells in the aqueous solution before dissolving. Under these conditions, rapid dissolution and dispersion of the thickener can be achieved; the low mixing speed suppresses foaming of the surfactant; and the uniformity of the thickener in the solution can be ensured. After adding the thickener, this step yields a dispersion emulsion of nano-silica.

[0021] Preferably, the thickener is one or both of anionic polyacrylamide and polyethylene glycol.

[0022] The addition of thickener increases the viscosity of the dispersion solution, allowing the nano-silica particles to remain suspended in the solution and preventing secondary agglomeration of the already uniformly dispersed nano-silica particles, thus further improving the dispersion of nano-silica. The fully dispersed nano-silica particles are beneficial for the complete progress of the subsequent grafting reaction.

[0023] Preferably, the hydrolysis solution of the silane coupling agent is obtained by mixing anhydrous ethanol and deionized water in a ratio of 2-4:1, adding 0.03-0.05 wt% of the silane coupling agent, and reacting at 40-60°C for 20-60 min. The preferred reaction speed is 300-500 rpm.

[0024] Preferably, the stearic acid solution is obtained by mixing stearic acid and benzene solvent at a weight ratio of 0.1 to 0.3:1.

[0025] More preferably, the benzene solvent is xylene. Xylene has a low boiling point and can be discharged as the temperature rises in subsequent preparation processes, reducing the impact of xylene on subsequent reactions.

[0026] A modified colored asphalt, characterized in that: the raw materials include, by weight, 50-68 parts petroleum resin, 24-36 parts base oil, 5-15 parts polymer modifier SBR or SBS, and 1-5 parts of the asphalt modifier mentioned above.

[0027] Preferably, the preparation method includes the following steps:

[0028] 1) Mix the base oil and polymer modifier by weight at 130~160℃ for 10~30min, then add the asphalt modifier and mix thoroughly.

[0029] 2) Add petroleum resin and react at 120~140℃ for 30~40 min, then heat to 140~150℃ and maintain the temperature for 60~100 min to obtain modified colored asphalt.

[0030] The polymer modifier is premixed with the base oil. The polymer modifier absorbs the light components in the base oil and swells. The intertwined polymer chains are opened up, which is conducive to the rapid formation of a three-dimensional network structure by the polymer modifier, so as to better exert the modification effect. Meanwhile, since the amount of base oil added is higher than that of polymer modifier, some base oil is in a fluid state, reducing the viscosity of the system. At this time, the addition of modified nano-silica particles can reduce the dispersion resistance of the modified nano-silica particles and promote their uniform dispersion. After surface modification, the modified nano-silica particles have improved compatibility with organic substances, which is beneficial to promoting the dispersion of modified nano-silica particles in the base asphalt. After surface modification, the nano-silica particles have a large number of organic long chains grafted on their surface, which can intertwine with the three-dimensional network structure of the polymer modifier, preventing the self-polymerization of the modified nano-silica particles. This solves the problem of decreased low-temperature performance and significant increase in viscosity of modified colored asphalt caused by the self-polymerization of nano-silica particles. At the same time, this limiting effect also has a reverse effect on the three-dimensional network structure of the polymer modifier, reducing the fluidity of colored asphalt at high temperatures, thereby improving the high-temperature performance of colored asphalt. The uniformly dispersed modified nano-silica particles can act as a lubricant under the action of external shear force, thereby reducing the rotational viscosity of colored asphalt. Furthermore, due to the uniform dispersion of the modified nano-silica particles, the anti-aging properties of colored asphalt are significantly improved.

[0031] Petroleum resin, as a thickener, exhibits good compatibility with base oils. When added to the modification system, it dissolves rapidly in the base oil, increasing the consistency of the modified system and thus limiting the self-aggregation of modified nano-silica particles, thereby improving their dispersibility. Simultaneously, as a high softening point component, petroleum resin enhances the high-temperature performance of colored asphalt when added. Therefore, the combined effect of these components improves the dispersibility of modified nano-silica particles, thereby enhancing the high and low temperature performance of colored asphalt.

[0032] Preferably, the petroleum resin is one or more of coumarone resin, terpene resin, fully hydrogenated petroleum resin, and semi-hydrogenated petroleum resin in any proportion.

[0033] Preferably, the base oil is one or more of naphthenic oil, low aromatic oil, furfural extract oil, and high aromatic oil in any proportion, with a flash point >230℃ and a kinematic viscosity of less than 50 Pa·s at 40℃.

[0034] Preferably, the polymer modifier SBR is in granular form, with a styrene content of 22.5-24.5% and a tensile strength ≥15.0 MPa.

[0035] Preferably, the polymer modifier SBS has an S / B (weight ratio) of 30 / 70 and a melt flow rate (g•10 min). -1 0.1~5.

[0036] Compared with the prior art, the beneficial effects of this invention are: it significantly improves the dispersibility of inorganic nano-modifiers in asphalt, the nano-modifiers have good compatibility with asphalt, are evenly dispersed, do not agglomerate, do not have low-temperature brittleness, limit high-temperature fluidity, and improve the high and low temperature performance of colored asphalt. Detailed Implementation

[0037] The present invention will be further described below with reference to the embodiments, and Embodiment 2 is the preferred embodiment of the present invention. In the following embodiments and comparative examples, nano-silica and stearic acid are commercially available products; the polymer modifier SBS is SBS produced by Sinopec Baling Branch: S / B (weight ratio) 30 / 70, melt flow rate (g•10 min) -1 0.1-5; the polymer modifier SBR is a commercially available product with a styrene content of 22.5-24% and a tensile strength ≥15.0 MPa; the base oil flash point is >230℃ and the kinematic viscosity at 40℃ is less than 50 Pa·s.

[0038] Example 1

[0039] An asphalt modifier, the preparation method of which includes the following steps:

[0040] 1) Sodium hydroxide and deionized water are mixed at a weight ratio of 0.3:1 to obtain a sodium hydroxide solution. The solution is heated to 60°C, and nano-SiO2 powder is added under stirring. After filtration, the alkali-treated nano-SiO2 powder is obtained.

[0041] 2) A sodium benzenesulfonate solution was obtained by mixing deionized water with sodium alkylbenzenesulfonate and polyacrylamide at a weight ratio of 95:5:0.05. The mixture was stirred at 60°C and 400 rpm for 60-80 min. Then, the alkali-treated nano-SiO2 powder was slowly added and stirred for another 30-60 min to obtain a nano-SiO2 dispersion emulsion.

[0042] 3) Anhydrous ethanol and deionized water were mixed at a weight ratio of 3:1. Silane coupling agent KH550 was slowly added, and the mixture was stirred at 50°C and 400 rpm for 20 min to obtain a silane coupling agent hydrolysate solution. The temperature was then raised to 75°C, and nano-SiO2 dispersion emulsion was slowly added. The mixture was stirred for another 150 min. The product was centrifuged, washed with ethanol, and dried in an 80°C oven for 70 min to obtain silane coupling agent modified nano-SiO2.

[0043] 4) Stearic acid and xylene were mixed at a mass ratio of 0.2:1 to obtain a stearic acid solution. Then, silane coupling agent-modified nano-SiO2 was uniformly dispersed in the solution under stirring and reacted at a constant temperature of 70℃ for 200 min. After centrifugation, washing, and drying, modified nano-SiO2, i.e., asphalt modifier, was obtained.

[0044] A modified colored asphalt comprises, by weight, 50 parts petroleum resin, 36 parts base oil, 11 parts polymer modifier SBR, and 3 parts asphalt modifier. The petroleum resin is Coumarone resin, and the base oil is naphthenic oil 4010.

[0045] The preparation method includes the following steps:

[0046] 1) Naphthenic oil 4010 and polymer modifier SBR are heated in an oven at 135℃ for 50 minutes, then reacted at 155℃ and 1500 rpm for 20 minutes. Asphalt modifier is then added and mixed for 40 minutes.

[0047] 2) After the coumarone resin is completely dissolved, react at 130℃ for 35 minutes, and then place it in a 145℃ oven for constant temperature development for 75 minutes to obtain modified colored asphalt.

[0048] Example 2

[0049] A modified colored asphalt, based on Example 1, has the following raw material settings: 53 parts petroleum resin, 27 parts base oil, 15 parts SBR polymer, and 5 parts asphalt modifier.

[0050] Other conditions are the same as in Example 1.

[0051] Example 3

[0052] A modified colored asphalt, based on Example 1, wherein the petroleum resin is set as a terpene resin and the base oil is set as low aromatic oil G26.

[0053] Other conditions are the same as in Example 1.

[0054] Example 4

[0055] A modified colored asphalt, based on Example 1, has the following raw material composition: 64 parts petroleum resin, 26 parts base oil, 8 parts SBS polymer, and 2 parts asphalt modifier.

[0056] Other conditions are the same as in Example 1.

[0057] Example 5

[0058] A modified colored asphalt, based on Example 1, has the following raw material settings: 57 parts petroleum resin, 30 parts base oil, 10 parts SBS polymer, and 3 parts asphalt modifier.

[0059] Other conditions are the same as in Example 1.

[0060] Example 6

[0061] An asphalt modifier, based on Example 1, has a surface modifier set as sodium alkyl sulfonate and a silane coupling agent set as KH570. In its preparation method, step 1) has a weight ratio of sodium hydroxide to water of 0.5:1.

[0062] Other conditions are the same as in Example 1.

[0063] Example 7

[0064] An asphalt modifier, based on Example 1, wherein in its preparation method, the weight ratio of deionized water to sodium alkylbenzene sulfonate and polyacrylamide in step 2) is set to 94:5:0.1, and the weight ratio of sodium hydroxide to water in step 1) is set to 0.1:1.

[0065] Other conditions are the same as in Example 1.

[0066] Comparative Example 1

[0067] A modified colored asphalt, based on Example 1, uses nano-silica without surface modification treatment as the asphalt modifier.

[0068] Other conditions are the same as in Example 1.

[0069] Comparative Example 2

[0070] An asphalt modifier is prepared by treating nano-SiO2 powder according to steps 1) and 2) of its preparation method, obtaining a nano-SiO2 dispersion emulsion, filtering, washing with ethanol, and drying at 80°C to obtain the asphalt modifier.

[0071] Other conditions are the same as in Example 1.

[0072] Comparative Example 3

[0073] An asphalt modifier, based on Example 1, is prepared by directly treating nano-SiO2 powder in step 3) instead of steps 1) and 2) to obtain silane coupling agent modified nano-SiO2, which is then used as an asphalt modifier.

[0074] Other conditions are the same as in Example 1.

[0075] Comparative Example 4

[0076] An asphalt modifier, based on Example 1, is prepared by directly using step 4) instead of steps 1), 2), and 3) to process nano-SiO2 powder, thereby obtaining stearic acid-modified nano-SiO2, which is used as an asphalt modifier.

[0077] Other conditions are the same as in Example 1.

[0078] Comparative Example 5

[0079] An asphalt modifier, based on Example 1, is prepared by directly using steps 3) and 4) instead of steps 1) and 2) to treat the nano-SiO2 powder, thereby obtaining silane coupling agent and stearic acid modified nano-SiO2, which is used as an asphalt modifier.

[0080] Other conditions are the same as in Example 1.

[0081] Comparative Example 6

[0082] An asphalt modifier, based on Example 1, is prepared by treating nano-SiO2 powder without step 2), but by sequentially treating it with steps 1), 3), and 4) to obtain surface-modified nano-SiO2, which is then used as an asphalt modifier.

[0083] Other conditions are the same as in Example 1.

[0084] Comparative Example 7

[0085] An asphalt modifier, based on Example 1, is prepared by treating nano-SiO2 powder without step 1), but by sequentially treating it with steps 2), 3), and 4) to obtain surface-modified nano-SiO2, which is then used as an asphalt modifier.

[0086] Other conditions are the same as in Example 1.

[0087] Comparative Example 8

[0088] A modified colored asphalt, based on Example 1, is prepared using the following steps:

[0089] 1) Add coumarone resin to naphthenic oil 4010 according to the weight ratio, dissolve, and react for 35 min.

[0090] 2) Add polymer modifier SBR and keep it at a constant temperature of 135℃ for 50 minutes. Then, react at 155℃ and a stirring speed of 1500 rpm for 20 minutes. Add asphalt modifier, mix for 40 minutes, and place in a 145℃ oven for 75 minutes to develop and obtain modified colored asphalt.

[0091] Other conditions are the same as in Example 1.

[0092] Comparative Example 9

[0093] A modified colored asphalt, based on Example 1, is prepared using the following steps:

[0094] 1) Naphthenic oil 4010 and polymer modifier SBR are heated in an oven at 135℃ for 50 minutes by weight, and then reacted at 155℃ and 1500 rpm for 20 minutes by stirring. Under stirring, 2 parts of nano silica powder and 2 parts of silane coupling agent are added in sequence and mixed for 40 minutes.

[0095] 2) After the coumarone resin is completely dissolved, react for 35 minutes, and then place it in a 145℃ oven for 75 minutes to obtain modified colored asphalt.

[0096] Other conditions are the same as in Example 1.

[0097] Performance testing

[0098] The modified colored asphalt obtained from the above examples and comparative examples was subjected to performance tests. The ductility test was conducted according to method T0605-2011, the softening point test according to method GB / T 4507-2010, the rotational viscosity at 135℃ according to method T0625-2011, and the residual ductility ratio after aging according to method SH / T 0736-2003. The test results are shown in Table 1 below.

[0099] Table 1 Performance Test Results

[0100] .

[0101] A comparison of the test results from the examples and comparative examples shows that the modifier, modified colored asphalt, and their preparation method prepared in this invention can solve the problem of a significant decrease in the low-temperature ductility of modified asphalt at 5°C caused by the agglomeration of inorganic nano-SiO2 due to uneven dispersion during the modification process by physically dispersing and grafting nano-SiO2, thereby improving the low-temperature performance of nano-SiO2 modified asphalt. The modified SiO2 can significantly increase the softening point of the modified colored asphalt and further enable the modified colored asphalt to maintain good low-temperature ductility after high-temperature aging, indicating that the modified nano-SiO2 can improve the high-temperature performance and anti-aging performance of the modified colored asphalt. At the same time, it was found that the modification steps for nano-SiO2 in this invention are synergistic and interconnected, jointly achieving the modification of nano-SiO2 and solving the problem of SiO2 agglomeration. Furthermore, Examples 4 and 5 used SBS as a modifier. SBS is currently the most commonly used polymer in modified asphalt, primarily improving the high-temperature performance of asphalt while also considering its low-temperature performance. SBR, on the other hand, primarily improves the low-temperature performance of asphalt while also considering its high-temperature performance. Test results show that the modified nano-SiO2 has good applicability. In addition, the modification of high- and low-temperature nanomaterials can prevent a significant increase in the viscosity of the modified colored asphalt caused by the aggregation of inorganic nanomaterials. Meanwhile, Comparative Examples 8 and 9 show that the order of addition of the components and the preparation steps in this invention patent also have interrelated effects. Therefore, the above-mentioned preparation steps and methods in this invention patent have a synergistic and interrelated effect, jointly improving the performance of the modified colored asphalt.

[0102] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An asphalt modifier, characterized in that: The product comprises nano-silica that has undergone surface modification sequentially through a strong alkali solution, a surfactant solution, a hydrolyzed solution of a silane coupling agent, and a stearic acid solution. The strong alkali solution is obtained by mixing sodium hydroxide and water at a weight ratio of 0.1~0.5:

1. The surfactant solution is obtained by mixing water, surfactant, and thickener at a weight ratio of 94~95:5:0.05~0.

1. The hydrolyzed solution of the silane coupling agent is obtained by mixing anhydrous ethanol and deionized water at a weight ratio of 2~4:1, adding 0.03~0.05wt% of the silane coupling agent to the mixed solvent, and reacting at 40~60℃ for 20~60 min. The stearic acid solution is obtained by mixing stearic acid and benzene solvent at a weight ratio of 0.1~0.3:

1.

2. The asphalt modifier according to claim 1, characterized in that: The surface modification includes the following steps: 1) A strong alkaline solution is heated to 50~70℃ and then mixed with nano-silica powder for surface modification to obtain filter residue; 2) Heat the surfactant solution to 50~70℃ and mix it with the filter residue obtained in step 1) for 30~60 minutes to obtain a suspension; 3) The hydrolysis solution of the silane coupling agent is heated to 70~80℃ and the suspension obtained in step 2) is added. The reaction is carried out for 150~200 min. The product is centrifuged, washed and dried to obtain a solid. 4) The stearic acid solution and the solid obtained in step 3) are reacted at 60~80℃ for 180~240 min, centrifuged, washed and dried to obtain modified nano-silica.

3. The asphalt modifier according to claim 1 or 2, characterized in that: The surfactant solution is obtained by mixing water and surfactant at a weight ratio of 94~95:

5.

4. The asphalt modifier according to claim 1 or 2, characterized in that: The surfactant solution is obtained by mixing at 300-500 rpm for 60-80 minutes.

5. The asphalt modifier according to claim 1, characterized in that: The benzene solvent is xylene.

6. A modified colored asphalt, characterized in that: The raw materials, by weight, include 50-68 parts of petroleum resin, 24-36 parts of base oil, 5-15 parts of polymer modifier SBR or SBS, and 1-5 parts of asphalt modifier as described in any one of claims 1-5. The preparation method includes the following steps: 1) Mix the base oil and polymer modifier by weight at 130~160℃ for 10~30min, then add the asphalt modifier and mix thoroughly. 2) Add petroleum resin and react at 120~140℃ for 30~40 min, then heat to 140~150℃ and maintain the temperature for 60~100 min to obtain modified colored asphalt.