A method for preparing thermally reversible recycled epoxy asphalt

Abstract

This invention relates to a method for preparing thermally reversible recycled epoxy asphalt. The method involves reacting an epoxy resin main agent with a furan-containing compound to obtain a furan-functionalized epoxy main agent material; adding bismaleimide to an epoxy curing agent and mixing the mixture to obtain a maleimide-based epoxy curing agent material; mixing the two materials and then blending them with a base asphalt to obtain thermally reversible recycled epoxy asphalt. The thermally reversible recycled asphalt prepared by this invention exhibits excellent high and low temperature performance, mechanical properties, and adhesive properties. Furthermore, the constructed reversible cross-linked three-dimensional network enables the recyclability of the epoxy asphalt. This preparation method solves the problem of the difficulty in recycling existing epoxy asphalt.

Description

Technical Field

[0001] This invention relates to a method for preparing thermally reversible recycled epoxy asphalt, belonging to the field of materials preparation technology. Background Technology

[0002] Steel bridges, with their advantages of light weight, convenient erection, and short construction period, are widely used in long-span bridges. Ordinary asphalt pavement materials are prone to melting and deformation at high temperatures, and their adhesion to steel bridge decks decreases due to complex environmental changes, leading to pavement damage. Epoxy asphalt, as a thermosetting composite material, not only possesses the high elasticity and driving comfort of ordinary asphalt but also has high adhesion and weather resistance, thus finding widespread application in the paving of steel bridges spanning rivers and seas.

[0003] Epoxy asphalt is a thermosetting material prepared by mixing asphalt, epoxy resin, curing agent, and compatibilizer in a specific ratio. During use, once epoxy asphalt cures and forms a three-dimensional cross-linked network, it can no longer function as a binder and is difficult to recycle. With the widespread application of existing epoxy asphalt materials, it is foreseeable that a large amount of epoxy asphalt pavement waste will inevitably be generated. Therefore, designing a recyclable epoxy asphalt can contribute to alleviating the shortage of road engineering materials and reducing solid waste pollution. Currently, there is still a gap in the development of thermally reversibly recyclable epoxy asphalt materials. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the problem that current epoxy asphalt materials cannot be reused after aging, this invention provides a method for preparing thermally reversible regenerated epoxy asphalt.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0008] A method for preparing thermally reversible recycled epoxy asphalt, comprising the following steps:

[0009] S1. React epoxy resin main agent and a compound containing furan group to obtain furan-functionalized epoxy main agent material;

[0010] S2. Add bismaleimide to the epoxy curing agent and stir to mix, thus obtaining the maleimide epoxy curing agent material.

[0011] S3. The furan-functionalized epoxy base material is mixed with the maleimide epoxy curing agent material to obtain a mixed material;

[0012] S4. Blend the mixed material from step S3 with the base asphalt to obtain epoxy asphalt with thermally reversible regeneration function.

[0013] In the preparation method described above, preferably, in step S1, the epoxy resin main agent is E51 and E44, and the furan-containing compound is one or two of furanylamine and 2-furanyl chloride. Further, preferably, the mass ratio of E51 and E44 to the furan-containing compound is 25–40:25–40:20–80.

[0014] In the preparation method described above, preferably, in step S1, the reaction conditions are 40–150°C and the reaction time is 30–80 min.

[0015] In the preparation method described above, preferably, in step S2, the epoxy curing agent is one or both of 593 and T31; the mass ratio of epoxy resin curing agent to bismaleimide is 25-100:20-75.

[0016] Furthermore, the epoxy curing agent is preferably a mixture of epoxy curing agent 593 and T31 in a mass ratio of 25-50:5-120.

[0017] In the preparation method described above, preferably, in step S2, the stirring and mixing conditions are 25-35°C, the stirring rate is 300-500 rpm, and the stirring time is 30-60 min.

[0018] In the preparation method described above, preferably, in step S3, the furan-functionalized epoxy main agent material and the maleimide epoxy curing agent material are mixed in a mass ratio of 40-60:40-60.

[0019] In the preparation method described above, preferably, in step S4, the grade of the base asphalt is 70# or 90#.

[0020] In the method described above, preferably, in step S4, the mass ratio of the mixed material to the base asphalt is 40-70:30-60.

[0021] In the preparation method described above, preferably, in step S4, the epoxy asphalt with thermal reversible regeneration function is used after being sheared and stirred at a temperature of 130–160°C for 0.5–2 hours.

[0022] A thermally reversible regenerable epoxy asphalt obtained by the above preparation method.

[0023] This invention uses a chemical grafting method to graft furan-containing compounds onto epoxy base materials, while introducing bismaleimide into the curing agent to construct a Diels-Alder (DA reaction) thermally reversible epoxy crosslinking network, thereby preparing a thermally reversible regenerable epoxy asphalt material. By introducing a thermally reversible epoxy crosslinking network, the epoxy asphalt material is endowed with recyclability without affecting its performance.

[0024] (III) Beneficial Effects

[0025] The beneficial effects of this invention are:

[0026] This invention provides a method for preparing thermally reversible regenerable epoxy asphalt. The method involves reacting an epoxy resin main agent with a furan-containing compound and introducing bismaleimide into a curing agent. This bismaleimide is then added to the base asphalt in a specific ratio to prepare modified epoxy asphalt. The prepared modified asphalt exhibits excellent high and low temperature performance, mechanical properties, and adhesive properties. Furthermore, the constructed reversible cross-linked three-dimensional network enables the epoxy asphalt to be recycled under certain temperature conditions. This preparation method solves the problem of the difficulty in recycling existing epoxy asphalt.

[0027] Compared with the prior art, the present invention has the following advantages: (1) The preparation method of thermally reversible recycled epoxy asphalt provided by the present invention fills the gap of non-renewable epoxy asphalt; (2) The constructed thermally reversible epoxy asphalt has road performance comparable to traditional epoxy asphalt. Detailed Implementation

[0028] This invention uses a polymer containing furan groups to react with epoxy resin and introduces bismaleimide, which is then added to asphalt to prepare a thermally reversible epoxy asphalt. This epoxy asphalt can form a cross-linked, three-dimensional network structure at room temperature, exhibiting good adhesion and mechanical properties. At specific temperatures, it can undergo a Diels-Alder (DA) thermally reversible reaction and re-crosslink, enabling the recycling of road surface solid waste resources.

[0029] In this process, the compound containing furan groups reacts with the epoxy resin main agent. Preferably, the furan group is one or two of furanylamine and 2-furanyl chloride, which impart furan groups to the epoxy resin main agent. The preferred ratio of the epoxy resin main agent to the compound containing furan groups is 50-80:20-80. Extensive experimental studies have shown that when the amount of the compound containing furan groups exceeds 80 parts, the epoxy asphalt exhibits poor performance and fails to meet mechanical property requirements. Conversely, if the amount of the compound containing furan groups is too low, the epoxy asphalt exhibits poor thermal reversibility, or even lacks this function altogether. Ideally, the amount of the compound containing furan groups should be between 20-80 parts, which provides both thermal reversibility and good mechanical properties to the epoxy asphalt, meeting the required standards.

[0030] To better explain and facilitate understanding of the present invention, specific embodiments are described in detail below. The raw materials E51, E44, furanyl methylamine, epoxy curing agent 593, and epoxy curing agent T31 in the embodiments can be commercially available products.

[0031] Example 1

[0032] S1. By mass, 30 parts of E51, 30 parts of E44 and 40 parts of furanylamine are reacted in a reactor at 80°C and 300 rpm for 60 min to obtain furan-functionalized epoxy main agent material.

[0033] S2. Add 40 parts of bismaleimide to 50 parts of epoxy curing agent 593 and 10 parts of T31, add to a reaction vessel and stir and mix at 30°C and 300 rpm for 30 min to obtain the maleimide epoxy curing agent material.

[0034] S3. A mixed material is obtained by mixing furan-functionalized epoxy base material and maleimide epoxy curing agent material at a mass ratio of 40:50.

[0035] S4. The mixture obtained in step S3 is mixed with 60 parts of 70# base asphalt at 150℃ and 2000 rpm. After shearing and stirring for 1 hour, it is poured into a mold and cured at 60℃ for 4 days to obtain epoxy asphalt with thermal reversible regeneration function.

[0036] Example 2

[0037] S1. By mass, 40 parts of E51, 30 parts of E44, 20 parts of furanylamine, and 50 parts of 2-furanyl chloride are placed in a reaction vessel and reacted at 80°C and 300 rpm for 60 minutes to obtain furan-functionalized epoxy main agent material.

[0038] S2. Add 40 parts of bismaleimide to 40 parts of epoxy curing agent 593 and 20 parts of T31, add to a reaction vessel and stir and mix at 30°C and 300 rpm for 30 min to obtain the maleimide epoxy curing agent material.

[0039] S3. Furan-functionalized epoxy base material and maleimide epoxy curing agent material are mixed in a mass ratio of 50:50.

[0040] S4. Mix 40 parts of the mixed material obtained in step S3 with 60 parts of 90# base asphalt at 140℃ and 3000 rpm. After shearing and stirring for 1 hour, pour the mixture into a mold and cure it at 60℃ for 4 days to obtain epoxy asphalt with thermal reversible regeneration function.

[0041] Example 3

[0042] S1. By mass, 40 parts of E51, 30 parts of E44, 20 parts of furanylamine, and 50 parts of 2-furanyl chloride are reacted in a reactor at 80°C and 300 rpm for 60 min to obtain furan-functionalized epoxy main agent material.

[0043] S2. Add 30 parts of bismaleimide to 50 parts of epoxy curing agent 593 and 120 parts of T3, and stir and mix in a reactor at 30°C and 300 rpm for 30 min to obtain the epoxy curing agent material of maleimide.

[0044] S3. Furan-functionalized epoxy base material and maleimide epoxy curing agent material are mixed at a mass ratio of 60:40.

[0045] S4. The mixed material obtained in step S3 is mixed with 50 parts of 70# base asphalt at 150℃ and 2000 rpm. After shearing and stirring for 0.5 hours, it is poured into a mold and cured at 60℃ for 4 days to obtain epoxy asphalt with thermal reversible regeneration function.

[0046] Comparative Example 1

[0047] (1) By mass, E51 (30 parts) and E44 (30 parts) are reacted in a reactor at 80°C and 300 rpm for 60 min to obtain epoxy main agent material; epoxy curing agent 593 (50 parts) and T31 (50 parts) are mixed in a reactor at 30°C and 300 rpm to obtain traditional epoxy curing agent material; epoxy main agent material and curing agent material are mixed at a mass ratio of 60:40 to obtain traditional epoxy material.

[0048] (2) Mix 40 parts of the traditional epoxy material prepared in step (1) with 60 parts of 70# base asphalt at 160℃ and 2000 rpm, shear and stir for 0.5 h, pour into a mold, and cure at 60℃ for 4 days to obtain the traditional epoxy asphalt.

[0049] Comparative Example 2

[0050] (1) By mass, 40 parts of E51, 30 parts of E44 and 85 parts of furfur alcohol are reacted in a reactor at 80°C and 300 rpm for 60 min to obtain furan-functionalized epoxy main agent material.

[0051] (2) Add 30 parts of maleimide to 50 parts of epoxy curing agent 593 and 120 parts of T31, and stir and mix in a reactor at 30°C and 300 rpm for 30 min to obtain the epoxy curing agent material of maleimide.

[0052] (3) The furan-functionalized epoxy main agent and the maleimide epoxy curing agent are mixed in a mass ratio of 50:50;

[0053] (4) The mixture obtained in step S3 is mixed with 50 parts of 70# base asphalt at 150°C and 2000 rpm. After shearing and stirring for 0.5 h, it is poured into a mold and cured at 60°C for 4 days to obtain epoxy asphalt.

[0054] The materials obtained above were tested for tensile strength and elongation at break according to GB / T528-2009 Determination of tensile properties of vulcanized rubber or thermoplastic rubber, and for toughness and Young's modulus according to GB-T 1040.2-2022 Determination of tensile properties of plastics. The results are shown in Table 1.

[0055] Table 1. Performance comparison of thermally reversible epoxy asphalt and comparative epoxy asphalt

[0056]

[0057] As can be seen from Table 1, compared with Comparative Example 1, the epoxy asphalt of Examples 1-3 has significantly better toughness and elongation at break than traditional epoxy asphalt.

[0058] After the epoxy asphalt specimens were crushed, they were regenerated at 80℃, and then specimens were prepared for testing. The properties are shown in Table 2 below.

[0059] Table 2. Performance Comparison of Regenerated Thermally Reversible Epoxy Asphalt and Traditional Epoxy Asphalt

[0060]

[0061] In Table 2, Comparative Example 1 lacks data because traditional epoxy resins cannot be remolded after degradation, making it impossible to measure mechanical properties and thus unusable for recycling. Comparative Example 2 shows poor performance after regeneration, only 50% of its original performance, indicating a significant performance drop. Examples 1-3 of this invention, however, yielded measurable data, demonstrating the ability to regenerate new test specimens. The performance differences between the regenerated and original specimens in the examples are minimal, with a performance recovery rate of approximately 90%. In contrast, traditional epoxy asphalt samples cannot be re-prepared for performance testing, indicating a lack of recyclability.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art can 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. A process for the preparation of a thermoreversible regenerable epoxy bitumen, characterized in that, It comprises the following steps: S1, the epoxy resin main agent and the compound containing furan group are reacted to obtain a furan functionalized epoxy main agent material; wherein the epoxy resin main agent is E51 and E44, and the compound containing furan group is one or both of furan methylamine and 2-furan acyl chloride; the mass ratio of the E51 and E44 to the compound containing furan group is 25-40:25-40:20-80, the reaction condition is 40-150℃, and the reaction time is 30-80 min; S2, the epoxy curing agent is mixed with the bismaleimide by stirring to obtain a bismaleimide epoxy curing agent material; the epoxy curing agent is one or both of 593 and T31; the mass ratio of the epoxy curing agent to the bismaleimide is 25-100:20-75; S3, the furan functionalized epoxy main agent material and the bismaleimide epoxy curing agent material are mixed to obtain a mixed material; S4, the mixed material of step S3 is blended with the base asphalt, and the epoxy asphalt with thermal reversible regeneration function is obtained after shearing and stirring at a temperature of 130-160℃ for 0.5-2h.

2. The production method according to claim 1, wherein The epoxy curing agent is a mixture of epoxy curing agent 593 and T31 with a mass ratio of 25-50:5-120.

3. The production method according to claim 1, wherein In step S2, the stirring condition is 25-35℃, the stirring rate is 300-500rpm, and the stirring time is 0.5-1h.

4. The production method according to claim 1, wherein In step S3, the furan functionalized epoxy main agent material and the bismaleimide epoxy curing agent material are mixed in a mass ratio of 40-60:40-60.

5. The production method according to claim 1, wherein In step S4, the base asphalt is 70# or 90#; and the mass ratio of the mixed material to the base asphalt is 40-70:30-60.

6. An epoxy asphalt with thermal reversible regeneration function obtained by the preparation method of any one of claims 1-5.

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