Asphalt modifier and method for preparing the same

Abstract

This invention relates to the field of road materials, specifically to an asphalt modifier and its preparation method. The asphalt modifier comprises specific thermoplastic styrene-butadiene rubber particles and thermoplastic carbon fiber composite waste particles. It can effectively solve problems such as bleeding, cracking, deformation, and rutting in asphalt pavements. Furthermore, its process is simple and low-cost, and it also enables the reuse of thermoplastic carbon fiber composite waste, meeting the requirements of green environmental protection.

Description

Technical Field

[0001] This invention relates to the field of road materials, specifically to an asphalt modifier and its preparation method. Background Technology

[0002] Asphalt is one of the main raw materials for road construction, and its performance has a significant impact on road lifespan. Road asphalt is used outdoors and is constantly exposed to sunlight, freezing, wind, vehicle traffic, and pedestrian trampling. Therefore, its high-temperature softening point, penetration, and abrasion resistance are important performance indicators. Generally, to improve the high-temperature softening point, 2-4 wt% of thermoplastic styrene-butadiene rubber (SBS) is added to current road asphalt to create SBS-modified asphalt. Improving the abrasion resistance of asphalt usually involves adding fillers such as resins and silicon carbide, but the effects are limited, and the addition is difficult and prone to causing uneven mixing. Patent CN113150569 provides a wear-resistant SBS-modified asphalt and its preparation method, mainly adding modified nanoparticles as a modifier. However, the composition of these nanoparticles is unclear, and the overall process route is complex and costly.

[0003] To significantly improve the stability and wear resistance of road asphalt, reduce costs, and promote environmental friendliness, using waste thermoplastic composite materials for asphalt modification is a promising technological approach. However, there are currently no reports on this method. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems existing in the prior art and provide an asphalt modifier based on the recycling of thermoplastic carbon fiber composite waste and its preparation method.

[0005] To achieve the above objectives, the present invention provides an asphalt modifier comprising thermoplastic styrene-butadiene rubber particles and thermoplastic carbon fiber composite waste particles, wherein the weight ratio of the thermoplastic styrene-butadiene rubber particles to the thermoplastic carbon fiber composite waste particles is 1:0.2-4; and the carbon fiber component content in the thermoplastic carbon fiber composite waste particles is 40-80 wt%.

[0006] A second aspect of the present invention provides a modified asphalt comprising the aforementioned asphalt modifier.

[0007] A third aspect of the present invention provides a method for preparing modified asphalt, the method comprising adding the above-mentioned asphalt modifier to molten asphalt, stirring and then shearing to obtain the modified asphalt.

[0008] The inventors of this invention have discovered that combining specific thermoplastic carbon fiber composite waste with thermoplastic styrene-butadiene rubber (SBR) in asphalt modification allows for synergistic effects. The two materials work together to undergo cross-linking polymerization with asphalt, resulting in physical and chemical modifications. This significantly increases the asphalt's high-temperature softening point and achieves a suitable penetration, thereby improving its thermal stability and wear resistance. This effectively solves problems such as bleeding, cracking, deformation, and rutting in asphalt pavements. Furthermore, the process for preparing this asphalt modifier is simple and inexpensive, while also enabling the reuse of thermoplastic carbon fiber composite waste, meeting the requirements of green environmental protection. Detailed Implementation

[0009] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0010] The present invention provides an asphalt modifier comprising thermoplastic styrene-butadiene rubber particles and thermoplastic carbon fiber composite waste particles, wherein the weight ratio of the thermoplastic styrene-butadiene rubber particles to the thermoplastic carbon fiber composite waste particles is 1:0.2-4; and the carbon fiber component content in the thermoplastic carbon fiber composite waste particles is 40-80 wt%.

[0011] According to the present invention, when the asphalt modifier is added to molten asphalt, the thermoplastic styrene-butadiene rubber, thermoplastic carbon fiber composite waste, and asphalt undergo a cross-linking polymerization reaction to generate a uniformly distributed, cross-linked network molecular structure, thereby improving various properties of the asphalt. The thermoplastic carbon fiber composite waste, due to the presence of a certain amount of the carbon fiber component, possesses excellent adhesive strength, promoting the cross-linking reaction while distributing within the formed network molecular structure to make the structure more compact. The thermoplastic resin component present in the thermoplastic carbon fiber composite waste facilitates its combination with the thermoplastic styrene-butadiene rubber and asphalt to generate polymer molecules with excellent properties. Through the synergistic effect of the thermoplastic carbon fiber composite waste and the thermoplastic styrene-butadiene rubber, the asphalt is physically and chemically modified, increasing its high-temperature softening point. The flexibility, mechanical strength, and wear and corrosion resistance of the asphalt are all significantly improved, resulting in good performance under both high and low temperature environments.

[0012] According to the present invention, in order to obtain the asphalt modifier with better modification effect and enhance the synergistic effect of the thermoplastic carbon fiber composite waste and the thermoplastic styrene-butadiene rubber during asphalt modification, preferably, the weight ratio of the thermoplastic styrene-butadiene rubber particles to the thermoplastic carbon fiber composite waste particles is 1:0.2-2, for example, it can be 1:0.4, 1:0.7, 1:1.5 and 1:2 and any range between these values.

[0013] According to the present invention, the carbon fiber component in the thermoplastic carbon fiber composite waste can enhance the bonding force, thereby facilitating the crosslinking reaction, and can also be dispersed in asphalt to further improve wear resistance and flexibility. In order to obtain a better asphalt modification effect, preferably, the carbon fiber component content in the thermoplastic carbon fiber composite waste particles is 55-65wt%, for example, it can be 55wt%, 58wt%, 63wt% and 65wt% and any value between them.

[0014] According to the present invention, in order to obtain polymer molecules with better performance through the crosslinking reaction and form a more stable network molecular structure, thereby enhancing the resistance of asphalt to mechanical wear and chemical corrosion, preferably, the raw material for the thermoplastic carbon fiber composite waste particles is selected from one or more of the following: prepreg waste and / or sheet waste of carbon fiber / polyetheretherketone composites, carbon fiber / polyaryletherketone composites, carbon fiber / polyphenylene sulfide composites, carbon fiber / polycarbonate composites, and carbon fiber / nylon composites. More preferably, the raw material for the thermoplastic carbon fiber composite waste particles is selected from one or more of the following: prepreg waste and / or sheet waste of carbon fiber / polyaryletherketone composites, carbon fiber / polyphenylene sulfide composites, and carbon fiber / polycarbonate composites. Since prepreg materials are more easily broken and have smaller cross-sections, they are more likely to form effective particles, thus making it easier to mix uniformly with the asphalt. Sheets, due to their larger particle size, are less effective than prepregs. Therefore, in the above selections, the source of the thermoplastic carbon fiber composite waste particles is preferably the corresponding prepreg waste.

[0015] According to the present invention, in order to make the thermoplastic carbon fiber composite waste particles easier to mix and disperse evenly, thereby achieving a better modification effect, the particle size of the thermoplastic carbon fiber composite waste particles is preferably 0.1-18 mm, more preferably 0.1-8 mm, for example, it can be 0.1 mm, 0.8 mm, 2 mm, 5 mm and 8 mm and any range between these values.

[0016] According to the present invention, in order to better match the carbon fiber composite waste, improve the high-temperature softening point of the asphalt and obtain a suitable penetration, and increase its flexibility and stability, preferably, the volatile matter of the thermoplastic styrene-butadiene rubber particles is ≤0.8wt%, preferably 0.01-0.5wt%, for example, it can be 0.08wt%, 0.2wt%, 0.3wt%, and 0.5wt%, or any value between these values. Preferably, the 300% tensile stress of the thermoplastic styrene-butadiene rubber particles is ≥1.5MPa, preferably 2.5-10MPa, for example, it can be 2.5MPa, 3.6MPa, 6MPa, and 10MPa, or any value between these values. Preferably, the tensile strength of the thermoplastic styrene-butadiene rubber particles is ≥12MPa, preferably 18-30MPa, for example, it can be 18MPa, 22MPa, 25MPa, and 30MPa, or any value between these values. Preferably, the elongation at break of the thermoplastic styrene-butadiene rubber granules is ≥500%, preferably 700%-1200%, for example, it can be 700%, 780%, 860%, and 1100%, or any value between these values. Preferably, the Shore A hardness of the thermoplastic styrene-butadiene rubber granules is ≥52, preferably 68-90, for example, it can be 68, 74, 83, and 90, or any value between these values. Preferably, the melt flow rate of the thermoplastic styrene-butadiene rubber granules is 0.01g-1g / 10min, preferably 0.01-0.5g / 10min, for example, it can be 0.05g / 10min, 0.25g / 10min, 0.38g / 10min, and 0.5g / 10min, or any value between these values.

[0017] According to the present invention, in order to make the thermoplastic styrene-butadiene rubber particles easier to mix and disperse evenly, thereby achieving a better modification effect, the particle size of the thermoplastic carbon fiber composite waste particles is preferably 0.1-18 mm, more preferably 0.1-8 mm, for example, it can be 0.1 mm, 0.8 mm, 2 mm, 5 mm and 8 mm and any range between these values.

[0018] According to the present invention, the preparation method of the asphalt modifier may include washing and drying the thermoplastic carbon fiber composite material waste and crushing it into particles, crushing the thermoplastic styrene-butadiene rubber into particles, and then mixing the thermoplastic styrene-butadiene rubber particles and the thermoplastic carbon fiber composite material waste particles.

[0019] A second aspect of the present invention provides a modified asphalt comprising the aforementioned asphalt modifier.

[0020] According to the present invention, in order to improve the modification effect and obtain the modified asphalt with better overall performance, preferably, the content of the asphalt modifier in the modified asphalt is 0.05-5wt%, more preferably 2-5wt%, for example, it can be 2wt%, 3wt%, 4wt% and 5wt% and any value between them.

[0021] A third aspect of the present invention provides a method for preparing modified asphalt, the method comprising adding the above-mentioned asphalt modifier to molten asphalt, stirring and then shearing to obtain the modified asphalt.

[0022] According to the present invention, the method for preparing the modified asphalt may include: heating the asphalt to 140-160°C to melt it, then heating it to 170-190°C, adding the asphalt modifier at a stirring speed of 1500-2500 r / min, and continuing to stir for 10-30 min to obtain the product. The modified asphalt is obtained by shearing the product in a high-speed shear mixer at a speed of 3000-5000 r / min for 15-60 min.

[0023] Thermoplastic carbon fiber composites containing carbon fiber components possess excellent mechanical properties and good heat resistance, but they are costly. While they offer the advantage of being remolded, the number of remolding cycles is limited, and they are prone to internal performance defects. Discarding waste thermoplastic carbon fiber composites results in incalculable losses. The recycling value of waste thermoplastic carbon fiber composites is high; therefore, considering energy efficiency, market factors, and environmental protection, their recycling is essential and important.

[0024] This invention relates to an asphalt modifier that effectively modifies asphalt by mixing waste thermoplastic carbon fiber composite materials with thermoplastic styrene-butadiene rubber (SBR) of suitable particle size and in a specific weight ratio. When used in a certain amount for asphalt modification, this modifier significantly improves the high-temperature softening point and achieves suitable penetration through a unique mechanism, thereby enhancing flexibility, wear resistance, and corrosion resistance, resulting in good performance of the asphalt under both high and low temperature conditions. Furthermore, the preparation method of this asphalt modifier is simple, requires minimal processing and equipment, and is inexpensive. It also reuses waste thermoplastic carbon fiber composite materials, avoiding the waste of high-value resources.

[0025] The present invention will be described in detail below through embodiments.

[0026] In the following examples, the waste thermoplastic carbon fiber composite material was a transitional production material from the pilot plant of Shanghai Petrochemical Composite Materials (used for testing carbon fiber composition content, with testing methods referring to ASTM D 3171-2022). The thermoplastic styrene-butadiene rubber was Sinopec YH-791H (volatile matter 0.28wt%, 300% tensile stress 3.2MPa, tensile strength 20.3MPa, elongation at break 765%, Shore A hardness 74, melt flow rate 0.1g / 10min). The asphalt was No. 90 asphalt. The pulverizer was a commercially available small pulverizer with a rotation speed of 32000r / min. All other equipment and materials used were conventional in the art.

[0027] Example 1 Waste carbon fiber / polyaryletherketone (PLEK) prepreg material (65 wt% carbon fiber content) was washed with water, dried, and then pulverized into 5 mm particles in a pulverizer. Thermoplastic styrene-butadiene rubber (SBR) was pulverized into 2 mm particles in the pulverizer. The SBR particles were then mixed thoroughly with the PBR particles (weight ratio 1:0.67) to obtain an asphalt modifier.

[0028] 500g of asphalt was melted in an oven at 155℃. The melted asphalt was then placed on a preheated hot plate, and the temperature was adjusted to maintain the asphalt at 185℃. 15g of asphalt modifier was added while stirring at 2500 rpm, and stirring continued for 15 minutes to obtain the product. The product was then sheared in a high-speed shear mixer at 4800 rpm for 40 minutes to obtain modified asphalt.

[0029] Example 2 Waste carbon fiber / polyaryletherketone (PLEK) composite prepreg (63 wt% carbon fiber content) was washed with water, dried, and then pulverized into 8 mm particles in a pulverizer. Waste carbon fiber / polyphenylene sulfide (PPS) composite prepreg (60 wt% carbon fiber content) was washed with water, dried, and then pulverized into 3 mm particles in a pulverizer. Thermoplastic styrene-butadiene rubber (SBR) was pulverized into 2 mm particles in a pulverizer. Thermoplastic SBR particles, PLEK / PPS waste particles, and PBR waste particles (weight ratio 1:0.5:0.5) were mixed evenly to obtain an asphalt modifier.

[0030] 500g of asphalt was melted in an oven at 160℃. The melted asphalt was then placed on a preheated hot plate, and the temperature was adjusted to maintain the asphalt at 190℃. 25g of asphalt modifier was added while stirring at 2000 rpm, and stirring continued for 20 minutes to obtain the product. The product was then sheared in a high-speed shear mixer at 4500 rpm for 30 minutes to obtain modified asphalt.

[0031] Example 3 Carbon fiber / polyphenylene sulfide composite prepreg waste (carbon fiber content 62 wt%) was washed with water, dried, and then crushed into particles with a diameter of 3 mm in a pulverizer. Carbon fiber / polycarbonate composite prepreg waste (carbon fiber content 56 wt%) was washed with water, dried, and then crushed into particles with a diameter of 1 mm in a pulverizer. Thermoplastic styrene-butadiene rubber was crushed into particles with a diameter of 4 mm in a pulverizer. Thermoplastic styrene-butadiene rubber particles, carbon fiber / polyphenylene sulfide composite prepreg waste particles, and carbon fiber / polycarbonate composite prepreg waste particles (weight ratio 1:0.22:0.18) were mixed evenly to obtain an asphalt modifier.

[0032] 500g of asphalt was melted in an oven at 140℃. The melted asphalt was then placed on a preheated hot plate, and the temperature was adjusted to maintain the asphalt at 170℃. 12g of asphalt modifier was added while stirring at 1500 rpm, and stirring continued for 30 minutes to obtain the product. The product was then sheared in a high-speed shear mixer at 3200 rpm for 60 minutes to obtain modified asphalt.

[0033] Example 4 The method of Example 1 differs in that thermoplastic styrene-butadiene rubber particles are mixed evenly with carbon fiber / polyaryletherketone composite prepreg waste particles (weight ratio of 1:3) to obtain asphalt modifier.

[0034] Example 5 The method of Example 1 differs in that thermoplastic styrene-butadiene rubber particles are mixed evenly with carbon fiber / polyaryletherketone composite prepreg waste particles (weight ratio of 1:4) to obtain asphalt modifier.

[0035] Example 6 The method of Example 1 is different except that the carbon fiber / polyaryletherketone composite prepreg waste (carbon fiber component content of 65 wt%) is replaced with carbon fiber / polyaryletherketone composite prepreg waste (carbon fiber component content of 44 wt%).

[0036] Example 7 The method of Example 1 is different except that the carbon fiber / polyaryletherketone composite prepreg waste (carbon fiber component content of 65wt%) is replaced with carbon fiber / polyaryletherketone composite prepreg waste (carbon fiber component content of 75wt%).

[0037] Example 8 The method of Example 1 is different except that the carbon fiber / polyaryletherketone composite prepreg waste (carbon fiber component content of 65wt%) is replaced with carbon fiber / polyphenylene sulfide composite prepreg waste (carbon fiber component content of 64wt%).

[0038] Example 9 The method of Example 1 is different except that the carbon fiber / polyaryletherketone composite prepreg waste (carbon fiber component content of 65 wt%) is replaced with carbon fiber / nylon composite prepreg waste (carbon fiber component content of 63 wt%).

[0039] Comparative Example 1 The method of Example 1 is different in that thermoplastic styrene-butadiene rubber particles and carbon fiber / polyaryletherketone composite prepreg waste particles (weight ratio of 1:0.01) are mixed evenly to obtain asphalt modifier.

[0040] Comparative Example 2 The method of Example 1 differs in that thermoplastic styrene-butadiene rubber particles are mixed evenly with carbon fiber / polyaryletherketone prepreg waste particles (weight ratio of 1:5) to obtain asphalt modifier.

[0041] Comparative Example 3 The method of Example 1 is different except that the carbon fiber / polyaryletherketone composite prepreg waste (carbon fiber component content of 65 wt%) is replaced with carbon fiber / polyaryletherketone composite prepreg waste (carbon fiber component content of 86 wt%).

[0042] Comparative Example 4 The method of Example 1 is different except that the carbon fiber / polyaryletherketone composite prepreg waste (carbon fiber component content of 65 wt%) is replaced with carbon fiber / polyaryletherketone composite prepreg waste (carbon fiber component content of 32 wt%).

[0043] Comparative Example 5 The method is the same as in Example 1, except that carbon fiber (purchased from Shanghai Petrochemical, grade SCF35S) is pulverized into particles with a diameter of 5 mm in a pulverizer, thermoplastic polyaryletherketone resin (purchased from Vigers, grade VICTREX AE 250) is pulverized into particles with a diameter of 5 mm in a pulverizer, and thermoplastic styrene-butadiene rubber is pulverized into particles with a diameter of 2 mm in a pulverizer. The thermoplastic styrene-butadiene rubber particles, carbon fiber particles, and thermoplastic polyaryletherketone resin particles (weight ratio 1:0.35:0.32) are then mixed evenly to obtain the asphalt modifier.

[0044] Comparative Example 6 Thermoplastic styrene-butadiene rubber is crushed into particles with a particle size of 5mm in a pulverizer to obtain thermoplastic styrene-butadiene rubber granules.

[0045] 500g of asphalt was melted in an oven at 155℃. The melted asphalt was then placed on a preheated hot plate, and the temperature was adjusted to maintain the asphalt at 185℃. 15g of thermoplastic styrene-butadiene rubber granules were added while stirring at 2500 rpm. After addition, stirring was continued for 15 minutes to obtain the product. The product was then sheared in a high-speed shear mixer at 4800 rpm for 40 minutes to obtain modified asphalt.

[0046] Test case The modified asphalts prepared in Examples 1-9 and Comparative Examples 1-6 were tested according to the "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering" (JTG E20-2011) to obtain high-temperature softening point and penetration data. The modified asphalt samples were then subjected to heat aging for 20 hours, and the penetration and softening point were tested again. The results are shown in Table 1.

[0047] Table 1

[0048] As shown in Table 1, the modified asphalts prepared using the technical solutions of this invention in Examples 1-9 all have higher softening points than those in Comparative Examples 1-6, and also exhibit suitable penetration. This demonstrates that the asphalt modifier based on thermoplastic carbon fiber composite waste prepared by this invention can increase the high-temperature softening point of asphalt at low cost, thereby improving the stability of asphalt and extending the service life of road asphalt.

[0049] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An asphalt modifier, characterized in that, The asphalt modifier comprises thermoplastic styrene-butadiene rubber particles and thermoplastic carbon fiber composite waste particles, wherein the weight ratio of the thermoplastic styrene-butadiene rubber particles to the thermoplastic carbon fiber composite waste particles is 1:0.2-4; and the carbon fiber component content in the thermoplastic carbon fiber composite waste particles is 40-80 wt%.

2. The asphalt modifier according to claim 1, wherein, The weight ratio of the thermoplastic styrene-butadiene rubber particles to the thermoplastic carbon fiber composite waste particles is 1:0.2-2.

3. The asphalt modifier according to claim 1 or 2, wherein, The carbon fiber component content in the waste particles of the thermoplastic carbon fiber composite material is 55-65 wt%.

4. The asphalt modifier according to any one of claims 1-3, wherein, The particle size of both the thermoplastic styrene-butadiene rubber granules and the thermoplastic carbon fiber composite waste granules is 0.1-18 mm, preferably 0.1-8 mm.

5. The asphalt modifier according to any one of claims 1-4, wherein, The raw materials for the thermoplastic carbon fiber composite waste particles are selected from one or more of the following: carbon fiber / polyetheretherketone composite materials, carbon fiber / polyaryletherketone composite materials, carbon fiber / polyphenylene sulfide composite materials, carbon fiber / polycarbonate composite materials, and carbon fiber / nylon composite prepreg waste and / or sheet waste.

6. The asphalt modifier according to claim 5, wherein, The raw materials for the thermoplastic carbon fiber composite waste particles are selected from one or more of the following: carbon fiber / polyaryletherketone composite materials, carbon fiber / polyphenylene sulfide composite materials, and carbon fiber / polycarbonate composite prepreg waste and / or sheet waste.

7. The asphalt modifier according to any one of claims 1-6, wherein, The volatile matter content of the thermoplastic styrene-butadiene rubber particles is ≤0.8wt%, preferably 0.01-0.5wt%. Preferably, the thermoplastic styrene-butadiene rubber granules have a 300% tensile stress ≥ 1.5 MPa, more preferably 2.5-10 MPa; Preferably, the tensile strength of the thermoplastic styrene-butadiene rubber granules is ≥12MPa, and more preferably 18-30MPa; Preferably, the elongation at break of the thermoplastic styrene-butadiene rubber granules is ≥500%, more preferably 700%-1200%; Preferably, the thermoplastic styrene-butadiene rubber particles have a Shore A hardness ≥ 52 degrees, and more preferably 68-90 degrees; Preferably, the melt flow rate of the thermoplastic styrene-butadiene rubber particles is 0.01g-1g / 10min, and more preferably 0.01-0.5g / 10min.

8. A modified asphalt, characterized in that, The modified asphalt includes the asphalt modifier described in any one of claims 1-7.

9. The modified asphalt according to claim 8, wherein, The content of the asphalt modifier is 0.05-5wt%, preferably 2-5wt%.

10. A method for preparing modified asphalt, characterized in that, The method includes adding the asphalt modifier according to any one of claims 1-7 to molten asphalt, stirring, and then shearing to obtain the modified asphalt.

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