Environmentally friendly stabilizer for modified asphalt and preparation method thereof

Abstract

The present invention provides an environmentally friendly stabilizer for modified asphalt and a preparation method thereof. The environmentally friendly stabilizer for modified asphalt provided by the present invention is mainly composed of 40-50 parts of bis-[3-(triethoxysilyl)propyl]-disulfide, 5-10 parts of triallylamine, 10-15 parts of linoleic acid, 5-10 parts of zinc stearate, and 25-30 parts of fumed silica. The stabilizer can not only improve the stability of the modified asphalt mixture, but also avoids the release of harmful gases such as hydrogen sulfide during the production process and is non-flammable and non-explosive, safer and more efficient. In addition, the preparation method is simple, energy-saving and environmentally friendly. From the experimental results of the stabilizers of the embodiments and comparative examples in the modified asphalt mixture, it can be seen that when the stabilizer provided by the present invention is applied to the modified asphalt mixture, no toxic gases such as hydrogen sulfide are produced, indicating that it is environmentally friendly and does not cause harm to the human body and the environment; and the comprehensive performance index is significantly better than the stabilizer currently containing industrial sulfur as the main component, and has very excellent storage stability.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt modification, and in particular to an environmentally friendly stabilizer for modified asphalt and a preparation method thereof. Background Art

[0002] To improve the overall performance of modified asphalt mixtures, industrial sulfur or a stabilizer primarily composed of industrial sulfur and a vulcanization accelerator is typically added during the production process. The addition of the stabilizer promotes the formation of a three-dimensional network structure within the modifier, effectively cross-linking the asphalt with the modifier, thereby stabilizing the modified asphalt system. The process of modifying asphalt with stabilizers primarily composed of industrial sulfur triggers a free radical reaction at high temperatures, releasing harmful gases such as hydrogen sulfide, which are extremely harmful to humans and the environment. However, the inherent odor of asphalt makes hydrogen sulfide difficult to detect, posing a risk to both humans and the environment. These stabilizers are flammable and explosive at high temperatures, posing a safety hazard during production. Summary of the Invention

[0003] The purpose of the present invention is to provide an environmentally friendly stabilizer for modified asphalt and a preparation method thereof. This stabilizer can not only improve the stability of the modified asphalt mixture, but also avoid the release of harmful gases such as hydrogen sulfide during the production process and is non-flammable and non-explosive, making it safer and more efficient. In addition, the preparation method of this stabilizer is simple, energy-saving and environmentally friendly.

[0004] In order to achieve the above-mentioned purpose of the invention, the technical solution provided by the present invention is:

[0005] The invention provides an environmentally friendly stabilizer for modified asphalt, which is composed of the following components in parts by weight: 40-50 parts of bis-[3-(triethoxysilyl)propyl]-disulfide, 3-5 parts of triallylamine, 15-25 parts of linoleic acid, 5-10 parts of zinc stearate, and 25-30 parts of fumed silica.

[0006] Bis-[3-(triethoxysilyl)propyl]-disulfide, a relatively stable vulcanizing crosslinker, undergoes a crosslinking reaction with the unsaturated double bonds of the SBS modifier dispersed in the asphalt during the modified asphalt mixing process, catalyzed by triallylamine and activated by zinc stearate, forming a stable network structure. Triallylamine, an organic amine containing an unsaturated alkyl chain, catalyzes the formation of free radicals from bis-[3-(triethoxysilyl)propyl]-disulfide, thereby accelerating the crosslinking reaction. Zinc stearate and linoleic acid act as dispersants and lubricants during the modifier dispersion process. The unsaturated double bonds in the linoleic acid molecule also participate in the crosslinking reaction, thereby improving the modifier's dispersibility in the asphalt. Fumed silica serves as a carrier in the stabilizer preparation process. In the modified asphalt mixture, it adsorbs volatile small molecules from the asphalt, reducing volatility and preventing flammability and explosion. The various components in the stabilizer interact with each other and complement each other, avoiding the release of toxic gases during the development of the modified asphalt mixture, while improving the stability and other comprehensive performance indicators of the modified asphalt mixture.

[0007] Based on the above solution, bis-[3-(triethoxysilyl)propyl] disulfide has a sulfur content of 13.5-15.5% and a volatile matter mass fraction of <2% at 105°C. As a silane coupling agent containing siloxy groups within its molecule, it belongs to the disulfide class of sulfides. At low temperatures, i.e., warehouse storage temperatures, it is very stable, non-self-igniting, and safe to store. At high temperatures, i.e., above 165°C (the development temperature of asphalt mixtures), it forms sulfur anions catalyzed by alkaline substances. These react with the SBS double bonds in the modified asphalt to form sulfur chains, creating a cross-linked network structure. This improves the stability of the modified asphalt mixture without releasing toxic hydrogen sulfide gases. When combined with the polymer chains in the modified asphalt, bis-[3-(triethoxysilyl)propyl] disulfide can also enhance the impact resistance and thermal stability of the modified asphalt mixture.

[0008] Based on the above scheme, the linoleic acid iodine value is >155 and the acid value is >195. Linoleic acid reacts with triallylamine to neutralize the acid, rendering the triallylamine non-alkaline at room temperature. It also remains unreactive when mixed with bis-[3-(triethoxysilyl)propyl]-disulfide, resulting in a more stable property. It only becomes alkaline above 165°C, the asphalt development temperature, breaking the ammonium salt ionic bonds and releasing the organic amine to act as a catalyst.

[0009] Based on the above scheme, the zinc stearate has a zinc content of 10.3-10.5%, a free acid content of less than 0.5% as stearic acid, and a particle size of 50-100 mesh. During the stabilizer preparation process, the zinc stearate acts as an active agent and lubricant, synergistically acting with triallylamine to catalyze the vulcanization and cross-linking reaction of bis-[3-(triethoxysilyl)propyl]-disulfide, thereby increasing the reactivity of the bis-[3-(triethoxysilyl)propyl]-disulfide.

[0010] Based on the above scheme, the median particle size of fumed silica is 7-80nm, and the specific surface area is 150-400m 2 / g. As an inorganic filler, fumed silica is stable and has strong surface adsorption. Therefore, during the mixing process of the stabilizer and modified asphalt, it can effectively adsorb organic components such as bis-[3-(triethoxysilyl)propyl]-disulfide, making it less volatile. When it comes into contact with the heating pipe of the asphalt development tank, it will not cause a flash explosion, avoiding combustion and explosion, thereby improving the safety of the stabilizer.

[0011] The present invention provides a method for preparing an environmentally friendly stabilizer for modified asphalt, comprising the following steps:

[0012] Step 1: Add 3-5 parts of triallylamine and dichloromethane to a reaction kettle and stir to react. Slowly add 15-25 parts of linoleic acid dropwise in an ice-water bath, controlling the reaction temperature to always be at 0°C. After the addition is complete, continue stirring and react for 2 hours. Then, add 5-10 parts of zinc stearate and 25-30 parts of fumed silica and stir evenly to obtain a mixture 1.

[0013] Step 2: Distill the solvent dichloromethane from the mixture 1 obtained in step 1 under a vacuum degree of 0.09 MPa to obtain a light yellow powder;

[0014] Step 3: dissolve 40-50 parts of bis-[3-(triethoxysilyl)propyl]-disulfide in dichloromethane solvent, then add the yellow powder obtained in step 2 and mix evenly. Evaporate the solvent dichloromethane under a vacuum degree of 0.09 MPa, and obtain an environmentally friendly stabilizer for modified asphalt after drying.

[0015] The beneficial effects of the technical solution provided by the present invention are:

[0016] 1. The bis-[3-(triethoxysilyl)propyl]-disulfide in the stabilizer acts as a silane coupling agent. Under the catalytic action of triallylamine, it undergoes a cross-linking reaction with the SBS double bonds in the modified asphalt, improving the stability of the modified asphalt while preventing the release of harmful gases such as hydrogen sulfide during production. Fumed silica, due to its strong adsorption capacity, absorbs organic components during the preparation of the modified asphalt mixture, making them less volatile. It also prevents flash explosions when in contact with the heating pipes of the asphalt development tank, thus improving the safety of the stabilizer.

[0017] 2. From the comparative experimental results of the stabilizers provided in the embodiments and comparative examples in modified asphalt mixtures, it can be seen that when the stabilizer provided in the present invention is applied to the modified asphalt mixture, no toxic gas such as hydrogen sulfide is produced, indicating that it is environmentally friendly; the comprehensive performance indicators are significantly better than the current stabilizers with industrial sulfur as the main component, and it has very excellent thermal storage stability.

[0018] 3. The preparation method of the stabilizer provided by the present invention is simple, energy-saving and environmentally friendly. DETAILED DESCRIPTION

[0019] The following will be combined with the contents of the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used in this specification are intended solely for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the related listed items. The materials, reagents, etc. used in the following examples, unless otherwise specified, are commercially available.

[0021] Example 1

[0022] An environmentally friendly stabilizer for modified asphalt is composed of the following components in parts by weight: 40 parts of bis-[3-(triethoxysilyl)propyl]-disulfide, 5 parts of triallylamine, 15 parts of linoleic acid, 10 parts of zinc stearate, and 30 parts of fumed silica.

[0023] The present invention provides a method for preparing an environmentally friendly stabilizer for modified asphalt, comprising the following steps:

[0024] Step 1: Add 5 parts of triallylamine and dichloromethane to a reaction kettle and stir to react. Then, slowly add 15 parts of linoleic acid dropwise in an ice-water bath, controlling the reaction temperature to always be at 0°C. After the addition is complete, continue stirring and react for 2 hours. Then, add 10 parts of zinc stearate and 30 parts of fumed silica and stir evenly to obtain a mixture 1.

[0025] Step 2: Distill the solvent dichloromethane from the mixture 1 obtained in step 1 under a vacuum degree of 0.09 MPa to obtain a light yellow powder;

[0026] Step 3: dissolve 40 parts of bis-[3-(triethoxysilyl)propyl]-disulfide in dichloromethane solvent, then add the yellow powder obtained in step 2 and mix evenly. Evaporate the solvent dichloromethane under a vacuum degree of 0.09 MPa, and obtain an environmentally friendly stabilizer for modified asphalt after drying.

[0027] Example 2

[0028] An environmentally friendly stabilizer for modified asphalt is composed of the following components in parts by weight: 50 parts of bis-[3-(triethoxysilyl)propyl]-disulfide, 3 parts of triallylamine, 17 parts of linoleic acid, 5 parts of zinc stearate, and 25 parts of fumed silica.

[0029] The present invention provides a method for preparing an environmentally friendly stabilizer for modified asphalt, comprising the following steps:

[0030] Step 1: Add 3 parts of triallylamine and dichloromethane to a reaction kettle and stir to react. Then, slowly add 17 parts of linoleic acid dropwise in an ice-water bath, controlling the reaction temperature to be always at 0°C. After the addition is complete, continue stirring and react for 2 hours. Then, add 5 parts of zinc stearate and 25 parts of fumed silica and stir evenly to obtain a mixture 1.

[0031] Step 2: Distill the solvent dichloromethane from the mixture 1 obtained in step 1 under a vacuum degree of 0.09 MPa to obtain a light yellow powder;

[0032] Step 3: dissolve 50 parts of bis-[3-(triethoxysilyl)propyl]-disulfide in dichloromethane solvent, then add the yellow powder obtained in step 2 and mix evenly. Evaporate the solvent dichloromethane under a vacuum degree of 0.09 MPa, and obtain an environmentally friendly stabilizer for modified asphalt after drying.

[0033] Example 3

[0034] An environmentally friendly stabilizer for modified asphalt is composed of the following components in parts by weight: 45 parts of bis-[3-(triethoxysilyl)propyl]-disulfide, 4 parts of triallylamine, 16 parts of linoleic acid, 5 parts of zinc stearate, and 30 parts of fumed silica.

[0035] The present invention provides a method for preparing an environmentally friendly stabilizer for modified asphalt, comprising the following steps:

[0036] Step 1: Add 4 parts of triallylamine and dichloromethane to a reaction kettle and stir to react. Then, slowly add 16 parts of linoleic acid dropwise in an ice-water bath, controlling the reaction temperature to be always at 0°C. After the addition is complete, continue stirring and react for 2 hours. Then, add 5 parts of zinc stearate and 30 parts of fumed silica and stir evenly to obtain a mixture 1.

[0037] Step 2: Distill the solvent dichloromethane from the mixture 1 obtained in step 1 under a vacuum degree of 0.09 MPa to obtain a light yellow powder;

[0038] Step 3: dissolve 45 parts of bis-[3-(triethoxysilyl)propyl]-disulfide in dichloromethane solvent, then add the yellow powder obtained in step 2 and mix evenly. Evaporate the solvent dichloromethane under a vacuum degree of 0.09 MPa, and obtain an environmentally friendly stabilizer for modified asphalt after drying.

[0039] Comparative Example 1

[0040] A stabilizer for modified asphalt, comprising the following components in parts by weight: 45 parts sulfur, 4 parts triallylamine, 16 parts linoleic acid, 5 parts zinc stearate, and 30 parts fumed silica. The sulfur is 200-mesh industrial grade sulfur.

[0041] A method for preparing a stabilizer for modified asphalt, comprising the following steps:

[0042] Step 1: Add 4 parts of triallylamine and dichloromethane to a reaction kettle and stir to react. Then, slowly add 16 parts of linoleic acid dropwise in an ice-water bath, controlling the reaction temperature to be always at 0°C. After the addition is complete, continue stirring and react for 2 hours. Then, add 5 parts of zinc stearate and 30 parts of fumed silica and stir evenly to obtain a mixture 1.

[0043] Step 2: Distill the solvent dichloromethane from the mixture 1 obtained in step 1 under a vacuum degree of 0.09 MPa to obtain a light yellow powder;

[0044] Step 3: Disperse 45 parts of sulfur in dichloromethane solvent, then add the yellow powder obtained in step 2 and mix evenly, evaporate the solvent dichloromethane under a vacuum degree of 0.09 MPa, and obtain a stabilizer for modified asphalt after drying.

[0045] Comparative Example 2

[0046] A stabilizer for modified asphalt, comprising 100 parts of sulfur, wherein the sulfur is 200-mesh industrial-grade sulfur.

[0047] Stabilizer test methods and results

[0048] 1. Prepare modified asphalt mixture and detect the release of hydrogen sulfide and other toxic gases:

[0049] Preparation and testing methods: 558g of 70# Qilu asphalt and 18g of aromatic oil were added to a 1-liter three-necked flask and heated to 180°C for stirring. Slowly add 24g of SBS modifier over 30 minutes and continue stirring for 1 hour until the SBS is completely melted. The temperature was lowered to 170°C, and 1.8g of stabilizer was slowly added to the asphalt mixture over 30 minutes. Nitrogen was introduced at a flow rate of approximately 20 bubbles / minute. The modified asphalt mixture was incubated at 170°C for 4 hours. The exhaust gas generated during the reaction was passed through a saturated lead acetate solution, and the exhaust gas outlet was tested for hydrogen sulfide using lead acetate test paper. Observe the lead acetate solution for the formation of a black precipitate, the solution becoming turbid, and the lead acetate test paper for blackening.

[0050] According to the different stabilizers added, the modified asphalt mixtures prepared are numbered as follows: the modified asphalt mixture obtained using the stabilizer of Example 1 is recorded as mixture 1; the modified asphalt mixture obtained using the stabilizer of Example 2 is recorded as mixture 2; the modified asphalt mixture obtained using the stabilizer of Example 3 is recorded as mixture 3; the modified asphalt mixture obtained using the stabilizer of Comparative Example 1 is recorded as mixture 4; and the modified asphalt mixture obtained using the stabilizer of Comparative Example 2 is recorded as mixture 5.

[0051] Table 1 Detection results of hydrogen sulfide toxic gases

[0052] Mixture 1 Mixture 2 Mixture 3 Mixture 4 Mixture 5 Lead acetate solution clarify clarify clarify Turbid, black Turbid, black Lead acetate test paper White White White Blackening Blackening

[0053] As shown in Table 1, the saturated lead acetate solutions in Mixes 1-3 were clear, and the lead acetate test paper did not turn black, indicating that no hydrogen sulfide-like toxic gases were released. The saturated lead acetate solutions in Mixes 4-5 produced a black lead sulfide precipitate, causing the solution to become turbid and the lead acetate test paper to turn black, indicating that hydrogen sulfide-like toxic gases were clearly generated. Therefore, the test results demonstrate that the stabilizer provided herein does not generate hydrogen sulfide-like toxic gases during production and use, and is environmentally friendly.

[0054] 2. Asphalt mixture evaluation results

[0055] The performance evaluation of the environmentally friendly stabilizer for modified asphalt provided by the present invention was characterized by testing the performance indicators of the prepared SBS-modified asphalt mixture. The SBS selected was Baling Petrochemical YH-791H, whose physical properties include linearity, S / B ratio of 30 / 70, Shore hardness of 76A, and a melt flow rate of 0.1 g / 10 min under test conditions of 5 kg and 200°C. The mass fraction of the modifier in the prepared asphalt mixture was 0.2%. The asphalt mixture was tested for various relevant indicators according to the "Test Procedures for Asphalt and Asphalt Mixtures for Highway Engineering" (JTGE20-2011).

[0056] The asphalt mixture preparation method is as follows:

[0057] In a 1.2-liter stainless steel straight-cylinder reactor with insulation, add 938g of Qilu 70# asphalt preheated to 180°C and 20g of aromatic oil. Raise the temperature to 180°C and slowly add 40g of SBS modifier over 30 minutes. After addition, shear at 5000 rpm until the modifier is completely melted. Then, change the stirring mode to 600 rpm and stir until there are no noticeable vortices on the liquid surface. Slowly add 2g of stabilizer over 15 minutes and continue to develop at 180°C for 3 hours. This completes the preparation of the modified asphalt mixture.

[0058] The numbering of the prepared modified asphalt mixtures refers to the numbering in the above test 1.

[0059] Table 2 Evaluation results of modified asphalt mixture

[0060]

[0061] The modified asphalt mixture evaluation results in Table 2 indicate that the SBS modified asphalt mixtures prepared using the stabilizer provided by the present invention in Mixes 1-3 exhibit significantly better comprehensive performance than Mixes 4-5, which were prepared using the stabilizer primarily composed of industrial sulfur in Comparative Examples 1-2. The evaluation results indicate that Mix 3, prepared using the stabilizer of Example 3, exhibited the best performance among Mixes 1-3.

[0062] Specifically, the modified asphalt mixture prepared from Mix 1-3 had a small storage stability segregation data, indicating that the modified asphalt mixture is not easy to phase separate and has excellent thermal storage stability. However, the storage stability segregation data of Mix 4-5 were 4.7 and 13 ° C, which were much larger than those of Mix 1-3, indicating that the modified asphalt mixture had poor stability. The mass change, penetration ratio, ductility, and penetration data of the modified asphalt mixture of Mix 1-3 measured by the thin film oven aging (TFOT or RTFOT) test showed very little change compared to the data before the aging test, indicating that the modified asphalt mixture has good stability and no significant performance degradation after short-term aging. In contrast, the thin film oven aging test data of Comparative Example 1-2 changed significantly, with obvious aging and poor stability.

[0063] Compared to Mixes 4-5, Mixes 1-3 exhibited higher penetration and ductility, indicating that the modified asphalt mixture prepared with Mixes 1-3 possessed excellent flexibility. A dynamic viscosity greater than 10,000 indicates that the modified asphalt mixture possessed excellent shear and retardation resistance, as well as good workability.

[0064] Therefore, the five components of bis-[3-(triethoxysilyl)propyl]-disulfide, triallylamine, linoleic acid, zinc stearate, and fumed silica are used in combination to obtain a modified asphalt mixture with good comprehensive performance, and replacing similar components cannot achieve the excellent effects of the present invention.

[0065] The above embodiments are only for illustrating the technical concept and features of the present invention. For ordinary technicians in this field, they can understand the contents of the present invention and implement them. They cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the technical solutions and technical concepts of the present invention should be included in the scope of protection of the present invention.

Claims

1. An environmentally friendly stabilizer for modified asphalt, characterized in that: The invention is composed of the following components in parts by weight: 40-50 parts of bis-[3-(triethoxysilyl)propyl]-disulfide, 3-5 parts of triallylamine, 15-25 parts of linoleic acid, 5-10 parts of zinc stearate, and 25-30 parts of fumed silica; wherein the sulfur content of the bis-[3-(triethoxysilyl)propyl]-disulfide is 13.5-15.5%.

2. The environmentally friendly stabilizer for modified asphalt according to claim 1, characterized in that The sulfur content of bis-[3-(triethoxysilyl)propyl]-disulfide is 13.5-15.5%, and the mass fraction of volatile matter at 105°C is <2%.

3. The environmentally friendly stabilizer for modified asphalt according to claim 1, characterized in that Linoleic acid iodine value>155, acid value>195.

4. The environmentally friendly stabilizer for modified asphalt according to claim 1, characterized in that The zinc content of zinc stearate is 10.3-10.5%, the free acid content calculated as stearic acid is less than 0.5%, and the particle size is 50-100 mesh.

5. The environmentally friendly stabilizer for modified asphalt according to claim 1, characterized in that The median particle size of fumed silica is 7-80nm, and the specific surface area is 150-400m 2 / g.

6. A method for preparing the environmentally friendly stabilizer for modified asphalt according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: add triallylamine and dichloromethane in corresponding weight parts to a reaction kettle and stir to react, slowly add linoleic acid in corresponding weight parts dropwise under an ice-water bath, and control the reaction temperature to be always at 0°C; after the addition is completed, continue stirring to react for 2 hours, then add zinc stearate and fumed silica in corresponding weight parts and stir evenly to obtain a mixture 1; Step 2: Distill the solvent dichloromethane from the mixture 1 obtained in step 1 under a vacuum degree of 0.09 MPa to obtain a light yellow powder; Step 3: Dissolve the corresponding weight parts of bis-[3-(triethoxysilyl)propyl]-disulfide in dichloromethane solvent, then add the yellow powder obtained in step 2 and mix evenly. Evaporate the solvent dichloromethane under a vacuum degree of 0.09 MPa, and obtain an environmentally friendly stabilizer for modified asphalt after drying.

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