Preparation method of rubber asphalt

Abstract

The invention discloses a preparation method of rubber asphalt, montmorillonite can form a micropore and mesopore type multi-dimensional gap structure through acid treatment and quaternary ammonium salt modification, the adsorption capacity of the montmorillonite can be improved, the montmorillonite is combined with tire rubber powder under the action of isocyanate, and the rubber asphalt is prepared. The modified montmorillonite is designed to be modified and is pre-compounded with the rubber powder, so that the hydrogen sulfide gas emitted by the rubber powder can be effectively removed during asphalt construction, the environment-friendly requirement is better met, and the harm to a human body is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of asphalt, and in particular to a method for preparing rubber asphalt. Background Art

[0002] Common ways to process waste tires include making them into rubber powder and adding it to asphalt to improve its high and low temperature, fatigue resistance and other properties. The addition of rubber powder can easily restrict the flow of asphalt and require higher temperatures during construction, which can easily lead to the release of smoke from the rubber powder. For example, the smoke includes hydrogen sulfide gas, which is toxic and smelly, affecting the environment and human health.

[0003] In response to this, some companies add zinc oxide to asphalt to remove hydrogen sulfide, but there are problems such as small removal amount, which need to be improved. Summary of the invention

[0004] To solve at least one of the above technical defects, the present invention provides the following technical solutions:

[0005] This application document discloses a method for preparing rubber asphalt, comprising the following steps:

[0006] First, the montmorillonite is treated with an acid, the acid-treated montmorillonite is compounded with zinc oxide, and the montmorillonite compounded with zinc oxide is modified with a quaternary ammonium salt;

[0007] Second, adding quaternary ammonium salt modified montmorillonite and diisocyanate type modifier into a solvent, and heating the reaction to prepare isocyanate modified montmorillonite;

[0008] Third, the pre-desulfurized and activated tire rubber powder and isocyanate-modified montmorillonite are placed in a solvent and heated to react to prepare a montmorillonite composite tire rubber powder;

[0009] Fourth, the montmorillonite composite tire rubber powder is mixed with base asphalt and additives to prepare rubber asphalt.

[0010] By acid-treating montmorillonite and modifying it with quaternary ammonium salt, the montmorillonite can form a microporous and mesoporous multi-dimensional void structure, which helps to improve its adsorption capacity. Under the action of isocyanate, the montmorillonite is combined with tire rubber powder. During high-temperature asphalt construction, the hydrogen sulfide emitted by the rubber powder is adsorbed by the montmorillonite and removed by zinc oxide.

[0011] Furthermore, the acid-treated montmorillonite is mixed with zinc salt and a carbonate solution is added, and the mixture is stirred for reaction, pyrolyzed, ground and crushed to form montmorillonite composited with zinc oxide. The zinc oxide and montmorillonite are combined into one through coprecipitation and pyrolysis, and the reaction is easy to operate.

[0012] Furthermore, the montmorillonite is treated with acetic acid, the zinc salt is zinc sulfate, the carbonate is sodium carbonate, and the pyrolysis temperature is 320-360°C.

[0013] Furthermore, the tire rubber powder is plasma activated with the following activation parameters: processing power 200-400W, processing time 260-340s, vacuum degree 10-30Pa. In an air atmosphere, plasma activation can improve the surface roughness of the rubber powder, and make the surface contain active groups such as hydroxyl groups, which are then combined with isocyanate to form a stable composite of montmorillonite and rubber powder. The hydrogen sulfide gas emitted by the rubber powder can be better absorbed in the asphalt, and the adsorption and removal efficiency is higher.

[0014] Furthermore, the diisocyanate modifier is isophorone diisocyanate, and the diisocyanate modifier and the quaternary ammonium salt modified montmorillonite are added to the solvent DMAC, the mass ratio of the diisocyanate modifier to the quaternary ammonium salt modified montmorillonite is 1:8-12, the temperature is raised to 70-90°C for reaction for 4-8h, and after solid-liquid separation, the isocyanate modified montmorillonite is dried and ground to obtain the isocyanate modified montmorillonite, so that the modification effect of the montmorillonite is improved under limited parameters.

[0015] Furthermore, the pre-desulfurized and activated tire rubber powder and isocyanate-modified montmorillonite are added to the solvent DMAC in a mass ratio of 100:1-4, the temperature is raised to 70-90°C for reaction for 4-8 hours, and after solid-liquid separation, the powder is dried and ground to obtain a montmorillonite composite tire rubber powder, so that the montmorillonite and the rubber powder are better combined under limited parameters.

[0016] Furthermore, the mass ratio of the base asphalt to the tire rubber powder is 5:0.8-1.2, and the auxiliary agent includes one or more of a softener, a modifier, and a cross-linking agent.

[0017] Furthermore, in the fourth step, the materials are mixed and then stirred, sheared and developed at high speed to form rubber asphalt.

[0018] Furthermore, the quaternary ammonium salt includes hexadecyltrimethylammonium bromide and tetradecyldimethylbenzylammonium chloride, and the mass ratio of the two is 2:1-3. The multi-quaternary ammonium salt combined with acid treatment can form a multi-dimensional void structure in montmorillonite, and the adsorption capacity is significantly improved.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention designs and modifies the modified montmorillonite and pre-compounds it with rubber powder, which can effectively remove the hydrogen sulfide gas emitted by the rubber powder during asphalt construction, better meets environmental protection requirements, and reduces harm to the human body. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with specific embodiments.

[0022] Example 1

[0023] The preparation method of rubber asphalt comprises the following steps:

[0024] First, sodium montmorillonite was dispersed in 0.8 mol / s acetic acid solution with a mass fraction of 15%, stirred at 85°C for 3.5 hours, filtered and washed with distilled water, dried and ground to obtain acid-treated montmorillonite.

[0025] The acid-treated montmorillonite and zinc sulfate are added to the solution, the mass proportions of montmorillonite and zinc sulfate are 10% and 4% respectively, and the sodium carbonate solution is added to the above montmorillonite and zinc sulfate solution, the mass proportions of sodium carbonate and zinc sulfate are the same, the reaction is stirred for 1.5 hours, the solid is filtered and heated to 350°C for thermal decomposition for 40 minutes, and the thermal decomposition product is crushed to obtain montmorillonite composited with zinc oxide.

[0026] Montmorillonite composited with zinc oxide is added to deionized water, and hexadecyltrimethylammonium bromide and tetradecyldimethylbenzylammonium chloride are added in a mass ratio of 2:1. The mass fractions of montmorillonite composited with zinc oxide and quaternary ammonium salt in the solution are 6% and 3%, respectively. The mixture is stirred and ultrasonically dispersed, and the temperature is raised to 38°C to react for 12 hours. The mixture is filtered and washed, and the obtained solid product is dried and ground to obtain quaternary ammonium salt-modified montmorillonite.

[0027] Second, add quaternary ammonium salt-modified montmorillonite and isophorone diisocyanate to the solvent DMAC (N, N-dimethylacetamide), the mass ratio of isophorone diisocyanate to quaternary ammonium salt-modified montmorillonite is 1:8, the mass fraction of quaternary ammonium salt-modified montmorillonite in the solution is 5%, the temperature is raised to 85°C and reacted for 7h, filtered and washed, and the obtained solid product is dried and ground to obtain isocyanate-modified montmorillonite (about 200 mesh).

[0028] Third, the pre-desulfurized and activated tire rubber powder was treated with a plasma treatment device for rubber powder (about 60 mesh) with a desulfurization degree of 30-40%. The parameters were: treatment power 300W, treatment time 320s, vacuum degree 15Pa, and air atmosphere. The pre-desulfurized and activated tire rubber powder and isocyanate-modified montmorillonite were placed in a solvent DMAC at a mass ratio of 100:1, stirred and heated to 80°C for reaction for 8h, filtered and washed, and the obtained solid product was dried and ground to obtain montmorillonite composite tire rubber powder.

[0029] Fourth, mix the montmorillonite composite tire rubber powder with base asphalt (70#), coal tar and SBS modifier. The mass ratio of base asphalt to tire rubber powder is 5:1. Coal tar is used as a softener with a mass ratio of 1.5% and SBS modifier of 1%. Mix them at 180°C with high-speed stirring for 10 minutes. Then add them to a high-speed shearing machine and refine them at 185°C and 3000r / min for 35 minutes. At the same time, add a cross-linking agent, which is a composite of sulfur and accelerator TMTD. The mass ratio of the two is 2:1 and the mass ratio of the cross-linking agent is 0.1%. Move the sheared mixture into a high-speed mixer and develop it at 175°C with high-speed stirring (1000r / min) for 2.5 hours to obtain the required rubber asphalt.

[0030] Example 2

[0031] The preparation method of rubber asphalt comprises the following steps:

[0032] First, sodium montmorillonite was dispersed in 1 mol / % acetic acid solution with a mass fraction of 10%, stirred at 80°C for 3 hours, filtered and washed with distilled water, dried and ground to obtain acid-treated montmorillonite.

[0033] The acid-treated montmorillonite and zinc sulfate are added to the solution, the mass proportions of montmorillonite and zinc sulfate are 9% and 3% respectively, and the sodium carbonate solution is added to the above montmorillonite and zinc sulfate solution, the mass proportions of sodium carbonate and zinc sulfate are the same, the reaction is stirred for 2 hours, the solid is filtered and heated to 350°C for 30 minutes for thermal decomposition, and the thermal decomposition product is crushed to obtain montmorillonite composited with zinc oxide.

[0034] Montmorillonite composited with zinc oxide is added to deionized water, and hexadecyltrimethylammonium bromide and tetradecyldimethylbenzylammonium chloride are added in a mass ratio of 2:1.5. The mass fractions of montmorillonite composited with zinc oxide and quaternary ammonium salt in the solution are 3% and 5%, respectively. The solution is stirred and ultrasonically dispersed, and the temperature is raised to 35°C for reaction for 12 hours. The solution is filtered and washed, and the solid product is dried and ground to obtain quaternary ammonium salt-modified montmorillonite.

[0035] Second, quaternary ammonium salt-modified montmorillonite and isophorone diisocyanate were added to the solvent DMAC (N, N-dimethylacetamide), the mass ratio of isophorone diisocyanate to quaternary ammonium salt-modified montmorillonite was 1:10, the mass fraction of quaternary ammonium salt-modified montmorillonite in the solution was 6%, the temperature was raised to 80°C and reacted for 8h, filtered and washed, and the obtained solid product was dried and ground to obtain isocyanate-modified montmorillonite (about 200 mesh).

[0036] Third, the pre-desulfurized and activated tire rubber powder was treated with a plasma treatment device for rubber powder (about 60 mesh) with a desulfurization degree of 30-40%. The parameters were: treatment power 320W, treatment time 290s, vacuum degree 15Pa, and air atmosphere. The pre-desulfurized and activated tire rubber powder and isocyanate-modified montmorillonite were placed in a solvent DMAC at a mass ratio of 100:1.5, stirred and heated to 80°C for reaction for 7h, filtered and washed, and the obtained solid product was dried and ground to obtain montmorillonite composite tire rubber powder.

[0037] Fourth, mix the montmorillonite composite tire rubber powder with base asphalt (70#), coal tar and SBS modifier. The mass ratio of base asphalt to tire rubber powder is 5:0.9. Coal tar is used as a softener with a mass ratio of 1.5% and SBS modifier of 1%. Mix them at 180°C with high-speed stirring for 10 minutes. Then add them to a high-speed shearing machine and refine them at 185°C and 3000r / min for 35 minutes. At the same time, add a cross-linking agent, which is a composite of sulfur and accelerator TMTD. The mass ratio of the two is 2:1 and the mass ratio of the cross-linking agent is 0.1%. Move the sheared mixture into a high-speed mixer and develop it at 175°C with high-speed stirring (1000r / min) for 2.5 hours to obtain the required rubber asphalt.

[0038] Comparative Example 1

[0039] Compared with Example 1, there is no compounding of tire rubber powder and montmorillonite in this example, and the two are added to the base asphalt independently.

[0040] Comparative Example 2

[0041] Compared with Example 1, no acid was used to treat the montmorillonite in this example.

[0042] Smoke detection was performed on the rubber asphalt prepared in the embodiment and the comparative example. Specifically, the rubber asphalt was moved into a container and heated, and the smoke release was detected at the same time. The performance test was also performed on the rubber asphalt prepared in the embodiment and the comparative example, as shown in Table 1.

[0043] Table 1

[0044] Smoke emission (g / kg) Average concentration of hydrogen sulfide / ppm 5℃ elongation (cm) Example 1 1.2 1.12 7.6 Example 2 1.0 0.86 7.6 Comparative Example 1 1.7 1.68 7.5 Comparative Example 2 1.6 1.54 7.6

[0045] It can be seen that after the rubber powder is compounded with montmorillonite through this process, the ability to adsorb and remove hydrogen sulfide in flue gas is greatly improved, the environmental protection is improved, and at the same time, there is no significant impact on other properties of rubber asphalt.

[0046] The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing rubber asphalt, characterized in that: The following steps are involved: First, the montmorillonite is treated with an acid, the acid-treated montmorillonite is compounded with zinc oxide, and the montmorillonite compounded with zinc oxide is modified with a quaternary ammonium salt; Second, adding quaternary ammonium salt modified montmorillonite and diisocyanate type modifier into a solvent, and heating the reaction to prepare isocyanate modified montmorillonite; Third, the pre-desulfurized and activated tire rubber powder and isocyanate-modified montmorillonite are placed in a solvent and heated to react to prepare a montmorillonite composite tire rubber powder; Fourth, the montmorillonite composite tire rubber powder is mixed with base asphalt and additives to prepare rubber asphalt.

2. The method for preparing rubber asphalt according to claim 1, characterized in that: The acid-treated montmorillonite is mixed with zinc salt and a carbonate solution is added, and the mixture is stirred for reaction, pyrolyzed, ground and crushed to form montmorillonite composited with zinc oxide.

3. The method for preparing rubber asphalt according to claim 1, characterized in that: The montmorillonite is treated with acetic acid, the zinc salt is zinc sulfate, the carbonate is sodium carbonate, and the pyrolysis temperature is 320-360°C.

4. The method for preparing rubber asphalt according to claim 1, characterized in that: The tire rubber powder is plasma activated, and the activation parameters are: processing power 200-400W, processing time 260-340s, vacuum degree 10-30Pa, under air atmosphere.

5. The method for preparing rubber asphalt according to claim 1, characterized in that: The diisocyanate modifier is isophorone diisocyanate. The diisocyanate modifier and the quaternary ammonium salt modified montmorillonite are added into the solvent DMAC, the mass ratio of the diisocyanate modifier to the quaternary ammonium salt modified montmorillonite is 1:8-12, the temperature is raised to 70-90°C for reaction for 4-8h, and the isocyanate modified montmorillonite is obtained by drying and grinding after solid-liquid separation.

6. The method for preparing rubber asphalt according to claim 1, characterized in that: The pre-desulfurized and activated tire rubber powder and isocyanate-modified montmorillonite are added to the solvent DMAC in a mass ratio of 100:1-4, the temperature is raised to 70-90° C. for reaction for 4-8 hours, and after solid-liquid separation, the powder is dried and ground to obtain the montmorillonite composite tire rubber powder.

7. The method for preparing rubber asphalt according to claim 1, characterized in that: The mass ratio of the base asphalt to tire rubber powder is 5:0.8-1.2, and the auxiliary agent includes one or more of a softener, a modifier, and a cross-linking agent.

8. The method for preparing rubber asphalt according to claim 1, characterized in that: In the fourth step, the materials are mixed and stirred at high speed, sheared, and developed to form rubber asphalt.

9. The method for preparing rubber asphalt according to claim 1, characterized in that: The quaternary ammonium salt includes hexadecyltrimethylammonium bromide and tetradecyldimethylbenzylammonium chloride, and the mass ratio of the two is 2:1-3.