A biomass asphalt emulsifier, its preparation method and application

Abstract

This invention discloses a biomass asphalt emulsifier, which is prepared by graft copolymerization of sodium lignin sulfonate and the amide intermediate in a solvent under the action of an initiator, through an amidation reaction of an amine compound and acrylic acid. The molar ratio of the amine compound to acrylic acid in the biomass asphalt emulsifier is (1-1.5):(1-1.5), the amount of lignin sulfonate is 40%-50% of the total mass of the amine compound and acrylic acid, the amount of initiator is 0.2%-2.8% of the total mass of the amine compound, acrylic acid, and lignin sulfonate monomers, and the mass ratio of the solvent to the total reactants is (1-1.2):(1-1.2). The preparation method of the biomass asphalt emulsifier of this invention is simple, with low production cost. The emulsifier has good water solubility and strong surface activity, belonging to the slow-cracking type of asphalt emulsifier. The emulsified asphalt produced by it is fine and uniform, with excellent storage stability, and has good application prospects in asphalt pavement construction.

Description

Technical Field

[0001] This invention relates to asphalt emulsifiers, their preparation methods, and applications, and more particularly to a biomass asphalt emulsifier, its preparation method, and its applications. It belongs to the field of transportation material preparation technology. Background Technology

[0002] Traditional hot-mix asphalt pavement construction involves mixing hot asphalt with hot aggregates before laying the pavement. This process results in significant energy waste and severe air pollution. In contrast, emulsified asphalt construction technology, with its advantages of energy conservation and minimal air pollution, has been widely adopted in pavement construction. Micro-surfacing technology, an important branch of emulsified asphalt technology, is used abroad for both asphalt and cement concrete pavement overlays. In my country, it is primarily used for asphalt pavements and cement concrete bridge decks and tunnel pavements, and is considered one of the most effective and economical methods for repairing ruts and other pavement defects.

[0003] Asphalt emulsifier is a surfactant and a key material in the production of emulsified asphalt. Adding a small amount can significantly reduce the surface tension at the oil-water interface and form an emulsifier molecular film at the oil-water interface, thereby emulsifying the asphalt. This allows asphalt particles to be uniformly and stably dispersed in the soap solution, giving the asphalt excellent fluidity at room temperature, facilitating construction at room temperature. Micro-surfacing emulsified asphalt requires a slow-setting, fast-curing type, demanding sufficient mixing time with aggregates and rapid demulsification and setting after paving for quick traffic opening. These performance requirements primarily depend on the asphalt emulsifier. Micro-surfacing places high technical demands on asphalt emulsifiers; their performance directly affects construction quality and progress.

[0004] Asphalt emulsifiers are classified into nonionic, anionic, cationic, and amphoteric asphalt emulsifiers based on whether their hydrophilic groups ionize and the charge they carry. US Patent 4338136 describes the preparation of asphalt emulsifiers by reacting C12-18 long-chain fatty acids with diethylenetriamine under specific conditions. The disadvantage of this method is that the prepared asphalt emulsifier is expensive, and when used in slurry seal construction, it results in long demulsification and molding times, leading to extended periods before traffic can resume. Chinese Patent CN1096714 describes the preparation of asphalt emulsifiers by reacting refinery byproducts, naphthenic acids, with alkenyl polyamines. The disadvantage of this method is that the supply of raw materials for the emulsifier is severely restricted, hindering its widespread application. Chinese Patent CN1861721A relates to a rosin cationic asphalt emulsifier. This emulsifier is prepared by reacting rosin and alkenyl polyamines to obtain a rosin intermediate, which is then condensed with different types of quaternary ammonium salt intermediates to obtain a high-performance rosin cationic asphalt emulsifier. Chinese patent CN101712625A discloses a method for synthesizing an amphoteric slow-cracking, fast-setting asphalt emulsifier. It involves reacting oleic acid with polyamines to generate amide polyamines, followed by a halogenation reaction with chloroacetic acid to obtain the asphalt emulsifier. A drawback of this method is the requirement for high-temperature reactions during preparation. Chinese patent CN101745340A discloses a method for preparing a cationic asphalt emulsifier. The main agent is obtained by reacting a mixed organic acid and an organic amine to obtain an intermediate, followed by a quaternization reaction. The auxiliary agents are nonionic surfactants and modifying agents. The drawbacks of this method are its cumbersome preparation steps, high cost, and the requirement for high-temperature reactions. The aforementioned asphalt emulsifier production processes are complex and costly.

[0005] Lignin, the second most abundant biomass material in the plant kingdom, is mainly found in trees. Globally, a large amount of lignin is produced annually in wastewater from the pulp and paper industry, hence the name "black liquor lignin." However, most of this lignin is discharged directly into rivers as "black liquor" or concentrated and burned, severely polluting the environment and difficult to utilize effectively. Lignin itself is a type of surfactant, and in recent years, it has been used as a highly efficient dispersant in printing inks, food processing, textiles, and wood coloring industries, resulting in more uniform dyeing. Based on its unique molecular structure, it can also be chemically modified into various industrial chemicals, with significant application potential.

[0006] Practice has proven that lignin sulfonates, modified from lignin in papermaking black liquor, can effectively reduce the environmental pollution caused by papermaking wastewater. Simultaneously, using lignin as a raw material for asphalt emulsifiers can reduce production costs, and the synthesis process is simple with widely available raw materials. Furthermore, the triethylenetetramine-acrylamide intermediate synthesized from the reaction of triethylenetetramine and acrylic acid is rich in amine groups, and graft copolymerization of this intermediate with lignin sulfonates can improve the emulsifying ability of the emulsifier. Therefore, developing novel biomass asphalt emulsifiers based on lignin that offer excellent performance and low cost has significant practical application value. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing biomass asphalt emulsifier and its application.

[0008] The biomass asphalt emulsifier of the present invention is characterized in that: the biomass asphalt emulsifier is prepared by graft copolymerization of sodium lignin sulfonate and the amide intermediate in a solvent under the action of an initiator, with an intermediate generated by an amidation reaction of an amine compound and acrylic acid, and a lignin sulfonate; wherein the amine compound is one or a combination of multiple of diethylenetriamine, triethylenetetraamine, and tetraethylenepentamine in any molar ratio; the lignin sulfonate is one of sodium lignin sulfonate and calcium lignin sulfonate; and the initiator is persulfate. The biomass asphalt emulsifier contains one or two of the following in any mass ratio: ammonium sulfate, potassium persulfate, hydrogen peroxide, and ascorbic acid, wherein the solvent is deionized water; the molar ratio of amine compounds to acrylic acid in the biomass asphalt emulsifier is (1-1.5):(1-1.5), the amount of lignin sulfonate is 40%-50% of the total mass of amine compounds and acrylic acid, the amount of initiator is 0.2%-2.8% of the total mass of amine compounds, acrylic acid, and lignin sulfonate monomers, and the mass ratio of solvent to total reactants is (1-1.2):(1-1.2).

[0009] In the above-mentioned biomass asphalt emulsifier: the amine compound is preferably triethylenetetramine, the lignin sulfonate is preferably sodium lignin sulfonate, and the initiator is preferably hydrogen peroxide and ascorbic acid, or a mixture of two of them in any mass ratio.

[0010] In the above-mentioned biomass asphalt emulsifier: the molar ratio of amine compounds to acrylic acid is preferably 1:1, the amount of lignin sulfonate is preferably 50% of the total mass of amine compounds and acrylic acid, the amount of initiator is preferably 0.5% of the total mass of amine compounds, acrylic acid and lignin sulfonate monomers, and the mass ratio of solvent to total reactants is preferably 1:1.

[0011] The preparation method of the biomass asphalt emulsifier of the present invention comprises the following steps:

[0012] (1) Preparation of triethylenetetramine-acrylamide intermediate

[0013] Under N2 purging conditions, acrylic acid is added to a four-necked flask, and the temperature is raised to 110-130°C with stirring. Then, a triethylenetetramine solution is slowly added dropwise. Under high temperature conditions, triethylenetetramine undergoes an amidation reaction with acrylic acid, and an amide intermediate is formed after 2-5 hours. The reaction formula is as follows:

[0014]

[0015] (2) Preparation of biomass asphalt emulsifier

[0016] The amide intermediate obtained in step (1) is added to deionized water, and sodium lignosulfonate is added simultaneously. The temperature is raised to 45-65°C, and then an initiator is added. Under the action of the initiator, sodium lignosulfonate and the amide intermediate undergo a graft copolymerization reaction, finally yielding the biomass asphalt emulsifier. In this biomass asphalt emulsifier, the molar ratio of triethylenetetramine to acrylic acid is (1-1.5):(1-1.5), the amount of lignosulfonate is 40%-50% of the total mass of triethylenetetramine and acrylic acid, the initiator is one or a mixture of two of hydrogen peroxide and ascorbic acid in any mass ratio, and its amount is 0.2%-2.8% of the total mass of triethylenetetramine, acrylic acid and lignosulfonate monomers, and the mass ratio of solvent water to total reactants is (1-1.2):(1-1.2). The reaction formula is as follows:

[0017]

[0018] In the above preparation method of biomass asphalt emulsifier: the temperature of the amidation reaction of triethylenetetramine and acrylic acid in step (1) is preferably 130°C; the temperature of the graft copolymerization reaction in step (2) is preferably 60°C.

[0019] The application of the biomass asphalt emulsifier described in this invention in the preparation of emulsified asphalt.

[0020] The application method is as follows: the biomass asphalt emulsifier is dissolved in water to prepare a soap solution. The soap solution is then heated to 70-80°C, and the pH value is adjusted to 10-12. Simultaneously, the asphalt is heated to 130°C. Both the soap solution and the asphalt are then poured into a colloid mill and ground for 2-5 minutes to obtain emulsified asphalt. The emulsified asphalt components consist of asphalt accounting for 55-65 wt.%, soap solution accounting for 35-45 wt.%, and the biomass asphalt emulsifier accounting for 1.5-3.0 wt.% of the total emulsified asphalt components.

[0021] A preferred embodiment of the above application method is as follows: the biomass asphalt emulsifier is dissolved in water to prepare a soap solution, which is then heated to 70°C and the pH value is adjusted to 11. Simultaneously, the asphalt is heated to 130°C. Both the soap solution and the asphalt are then poured into a colloid mill and ground for 3 minutes to obtain emulsified asphalt. The emulsified asphalt component comprises 60 wt.% asphalt and 40 wt.% soap solution, with the biomass asphalt emulsifier accounting for 2.0 wt.% of the total emulsified asphalt component.

[0022] This invention discloses a biomass asphalt emulsifier, its preparation method, and its application. The outstanding advantages and beneficial effects of this invention are reflected in:

[0023] 1) The biomass asphalt emulsifier synthesized in this invention adopts a two-step synthesis method, which avoids cumbersome reaction steps and can synthesize high-performance asphalt emulsifiers more conveniently and efficiently.

[0024] 2) The biomass asphalt emulsifier synthesized in this invention has good emulsification ability, and the emulsified asphalt has excellent high and low temperature performance and storage stability. All properties of the prepared emulsified asphalt meet the relevant requirements in the "Technical Specification for Construction of Highway Asphalt Pavement" (JTG F40-2004), and it has good application prospects in construction processes such as slurry seal and micro-surfacing.

[0025] 3) The raw material lignin of the biomass asphalt emulsifier of the present invention is cheaper and more widely available than the raw materials used in current asphalt emulsifiers, resulting in lower production costs for the asphalt emulsifier.

[0026] 4) The main raw material used in this invention is lignin sulfonate, which is modified from lignin in papermaking black liquor. This can effectively reduce the pollution of papermaking waste liquor to the environment.

[0027] 5) This invention uses triethylenetetramine to react with acrylic acid to synthesize a triethylenetetramine-acrylamide intermediate, which is rich in a large number of amine groups. After the intermediate is grafted and copolymerized with lignin sulfonate, it can improve the emulsifying ability of the emulsifier. Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments. The examples described below are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes, alterations, substitutions, combinations, or simplifications made to the embodiments based on the technical essence of the present invention shall be considered equivalent substitutions and shall fall within the scope of the technical solution of the present invention.

[0029] Unless otherwise specified, the methods described in the embodiments of this invention are conventional methods, and the materials and reagents used are obtained commercially unless otherwise specified.

[0030] Example 1:

[0031] 1. Preparation of biomass asphalt emulsifier

[0032] (1) Preparation of triethylenetetramine-acrylamide intermediate

[0033] Under nitrogen purging, 10.8 g of acrylic acid was added to a four-necked flask, and the temperature was raised to 110-130 °C with stirring. Then, 21.6 g of triethylenetetramine solution was slowly added dropwise. Under high temperature conditions, triethylenetetramine and acrylic acid underwent an amidation reaction for 3 hours to generate an amide intermediate.

[0034] (2) Preparation of biomass asphalt emulsifier

[0035] The amide intermediate obtained in step (1) was added to 64.8g of deionized water, and 32.4g of sodium lignosulfonate was added at the same time. The temperature was raised to 60°C, and then 1.08g of 30% hydrogen peroxide and 0.648g of ascorbic acid were added. Under the action of the initiator, sodium lignosulfonate and amide intermediate underwent graft copolymerization reaction to finally obtain the product biomass asphalt emulsifier.

[0036] 2. Preparation and performance testing of emulsified asphalt

[0037] Dissolve 20g of the biomass asphalt emulsifier in water, heat the soap solution to 70℃ to prepare 400g of soap solution, adjust the pH value to 11, then heat 600g of 70# base asphalt to 130℃, and finally pass the soap solution and base asphalt into a colloid mill and shear for 3 minutes to obtain emulsified asphalt.

[0038] The emulsified asphalt contains 60 wt.% asphalt and 40 wt.% soap solution; the soap solution contains 2.0 wt.% of biomass asphalt emulsifier, which accounts for 2.0 wt.% of the total emulsified asphalt components.

[0039] According to the test methods in "JTG E20-2011 Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering", the various indicators of the obtained emulsified asphalt were tested, and the test results are shown in Table 1.

[0040] Example 2:

[0041] In this embodiment, the biomass asphalt emulsifier was prepared in the same manner as in Example 1, except that the mass of hydrogen peroxide in step (1) was 0.54g.

[0042] In this embodiment, emulsified asphalt was prepared and its properties were tested in the same manner as in Example 1. The test results are shown in Table 1.

[0043] Example 3:

[0044] In this embodiment, the biomass asphalt emulsifier was prepared in the same manner as in Example 1, except that the amount of triethylenetetramine in step (1) was 32.4g.

[0045] In this embodiment, emulsified asphalt was prepared and its properties were tested in the same manner as in Example 1. The test results are shown in Table 1.

[0046] Example 4:

[0047] This embodiment prepares biomass asphalt emulsifier in the same manner as in Example 1, except that the initiator in step (2) is ammonium persulfate.

[0048] In this embodiment, emulsified asphalt was prepared and its properties were tested in the same manner as in Example 1. The test results are shown in Table 1.

[0049] Example 5:

[0050] In this embodiment, the biomass asphalt emulsifier was prepared in the same manner as in Example 1, except that the mass of sodium lignosulfonate in step (2) was 25.92g.

[0051] In this embodiment, emulsified asphalt was prepared and its properties were tested in the same manner as in Example 1. The test results are shown in Table 1.

[0052] Example 6:

[0053] This embodiment prepares biomass asphalt emulsifier in the same manner as in Example 1, except that the amine in step (1) is diethylenetriamine.

[0054] In this embodiment, emulsified asphalt was prepared and its properties were tested in the same manner as in Example 1. The test results are shown in Table 1.

[0055] Example 7:

[0056] This embodiment prepares biomass asphalt emulsifier in the same manner as in Example 1, except that the amine in step (1) is tetraethylenepentamine.

[0057] In this embodiment, emulsified asphalt was prepared and its properties were tested in the same manner as in Example 1. The test results are shown in Table 1.

[0058] Example 8:

[0059] This embodiment prepares biomass asphalt emulsifier in the same manner as in Example 1, except that the amount of triethylenetetramine in step (1) is 14.4g.

[0060] In this embodiment, emulsified asphalt was prepared and its properties were tested in the same manner as in Example 1. The test results are shown in Table 1.

[0061] Comparative Example 1:

[0062] In this comparative example, sodium lignosulfonate was used as an asphalt emulsifier, and emulsified asphalt was prepared and its performance was tested in the same manner as in Example 1. The test results are shown in Table 1.

[0063] Table 1: Performance Test Results of Emulsified Asphalt

[0064]

[0065] As shown in Table 1, the biomass asphalt emulsifier synthesized through graft copolymerization exhibits good low-temperature ductility and relatively good solubility. The emulsifier preparation method of this invention is simple, has low production costs, and the resulting emulsifier product has good water solubility and strong surface activity. It belongs to the slow-cracking asphalt emulsifier category. The emulsified asphalt produced using this emulsifier is fine and uniform, and has minimal impact on the low-temperature performance of the emulsified asphalt. All properties meet construction requirements, demonstrating promising application prospects in slurry seal and micro-surfacing applications.

Claims

1. A biomass asphalt emulsifier, characterized in that: The biomass asphalt emulsifier is prepared by graft copolymerization of sodium lignin sulfonate and amide intermediate in a solvent under the action of an initiator, with intermediate generated by the amidation reaction of amine compounds and acrylic acid. The amine compounds are one or a combination of multiple diethylenetriamine, triethylenetetraamine, and tetraethylenepentamine in any molar ratio; the lignin sulfonate is one of sodium lignin sulfonate and calcium lignin sulfonate; the initiator is a mixture of ammonium persulfate, potassium persulfate, or hydrogen peroxide and ascorbic acid in any mass ratio; and the solvent is deionized water. The molar ratio of amine compounds to acrylic acid in the biomass asphalt emulsifier is (1-1.5):(1-1.5); the amount of lignin sulfonate is 40%-50% of the total mass of amine compounds and acrylic acid; the amount of initiator is 0.2%-2.8% of the total mass of amine compounds, acrylic acid, and lignin sulfonate monomers; and the mass ratio of solvent to total reactants is (1-1.2):(1-1.2).

2. The biomass asphalt emulsifier according to claim 1, characterized in that: The amine compound is triethylenetetramine, the lignin sulfonate is sodium lignin sulfonate, and the initiator is a mixture of hydrogen peroxide and ascorbic acid in any mass ratio.

3. The biomass asphalt emulsifier according to claim 1 or 2, characterized in that: The biomass asphalt emulsifier has a molar ratio of amine compounds to acrylic acid of 1:1, an amount of lignin sulfonate of 50% of the total mass of amine compounds and acrylic acid, an amount of initiator of 0.5% of the total mass of amine compounds, acrylic acid and lignin sulfonate monomers, and a mass ratio of solvent to total reactants of 1:

1.

4. A method for preparing a biomass asphalt emulsifier, comprising the following steps: (1) Preparation of triethylenetetramine-acrylamide intermediate Under N2 conditions, acrylic acid is added to a four-necked flask, and the temperature is raised to 110-130 °C with stirring. Then, triethylenetetramine solution is slowly added dropwise. Under high temperature conditions, triethylenetetramine and acrylic acid undergo an amidation reaction, and an amide intermediate is generated after 2-5 hours. (2) Preparation of biomass asphalt emulsifier The amide intermediate obtained in step (1) is added to deionized water, and sodium lignosulfonate is added and heated to 45-65°C. Then an initiator is added. Under the action of the initiator, sodium lignosulfonate and the amide intermediate undergo a graft copolymerization reaction, and finally the biomass asphalt emulsifier is obtained. The molar ratio of triethylenetetramine to acrylic acid in the biomass asphalt emulsifier is (1-1.5):(1-1.5), the amount of lignosulfonate is 40%-50% of the total mass of triethylenetetramine and acrylic acid, the initiator is a mixture of hydrogen peroxide and ascorbic acid in any mass ratio, and its amount is 0.2%-2.8% of the total mass of triethylenetetramine, acrylic acid and lignosulfonate monomers. The mass ratio of solvent water to total reactants is (1-1.2):(1-1.2).

5. The method for preparing the biomass asphalt emulsifier according to claim 4, characterized in that: The temperature at which the triethylenetetramine reacts with acrylic acid in step (1) is 130°C; the temperature at which the graft copolymerization reaction occurs in step (2) is 60°C.

6. The application of the biomass asphalt emulsifier according to any one of claims 1-3 in the preparation of emulsified asphalt.

7. The application according to claim 6, characterized in that: The application method is as follows: Dissolve the biomass asphalt emulsifier in water to prepare a soap solution, then heat the soap solution to 70-80℃ and adjust the pH value to 10-12. Simultaneously, heat the asphalt to 130℃, then pour both the soap solution and the asphalt into a colloid mill and grind for 2-5 minutes to obtain emulsified asphalt. The emulsified asphalt component comprises 55-65 wt.% asphalt and 35-45 wt.% soap solution; the biomass asphalt emulsifier accounts for 1.5-3.0 wt.% of the total emulsified asphalt component.

8. The application according to claim 7, characterized in that: The application method is as follows: dissolve the biomass asphalt emulsifier in water to prepare a soap solution, then heat the soap solution to 70°C and adjust the pH value to 11. Simultaneously, heat the asphalt to 130°C, and then pour both the soap solution and the asphalt into a colloid mill and grind for 3 minutes to obtain emulsified asphalt. The emulsified asphalt component comprises 60 wt.% asphalt and 40 wt.% soap solution, with the biomass asphalt emulsifier accounting for 2.0 wt.% of the total emulsified asphalt component.

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