An activator for improving the activity of waste tire rubber powder and its preparation method

Abstract

The present invention relates to the technical field of rubber materials, and in particular to an activator for improving the activity of waste tire rubber powder and a preparation method thereof. The activator comprises an activator A and an activator B, wherein the activator A is a white oil solution of zinc stearate, and the content of zinc stearate is 3wt%-5wt%; and the activator B is a mixture of styrene, acrylamide, N-allylbenzenesulfonamide, an initiator and an antioxidant in a weight ratio of 10-20:5-15:1-3:0.1-0.5:1-2. The present invention effectively improves the activity of waste tire rubber powder by using the activator A and the activator B in combination, so that the prepared modified asphalt has good performance.

Description

Technical Field

[0001] The invention relates to the technical field of rubber materials, in particular to an activator for improving the activity of waste tire rubber powder and a preparation method thereof. Background Art

[0002] With the rapid development of the automobile industry and the transportation industry, the generation of waste tires is increasing. How to effectively deal with these waste tires has become an important environmental issue. Waste tires not only occupy a large amount of land resources, but also are not easy to degrade, which brings great pressure to the ecological environment. In order to achieve the recycling of resources, waste tire rubber powder, as a cheap material, is widely used in modified asphalt, rubber products, road engineering and other fields. Due to the large difference between the surface properties of rubber powder and the physical and chemical properties of asphalt, waste tire rubber powder often shows precipitation and agglomeration in asphalt, which makes the modification effect of rubber powder unable to be fully exerted, reducing the mechanical properties, crack resistance and aging resistance of modified asphalt.

[0003] In order to improve the compatibility of waste tire rubber powder with asphalt, common methods include surface treatment and chemical modification. The introduction of activators can improve the surface chemical properties of rubber powder, reduce the interfacial tension with asphalt, thereby promoting its dispersion performance in asphalt and effectively improving its compatibility with asphalt.

[0004] Patent technical document CN202110330068.6 provides a desulfurized rubber powder, comprising the following raw materials in parts by weight: 92-96 parts of waste tire rubber powder, 2-4.5 parts of desulfurizer, 1.5-4 parts of activator and 0.1-0.6 parts of anti-aging agent, wherein the desulfurizer includes desulfurizer RVS. The desulfurized rubber powder provided by the invention can effectively reduce the viscosity of rubber asphalt and improve its storage stability. However, the cross-linked network structure of waste tire rubber powder will lead to poor flexibility of its molecular chain, and traditional activators may have uneven local activation, resulting in poor final effect. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide an activator for improving the activity of waste tire rubber powder and a preparation method thereof, so as to solve the problem that the compatibility of waste tire rubber powder and asphalt is poor, resulting in poor modification effect of rubber powder modified asphalt.

[0006] Based on the above purpose, the present invention provides an activation method for improving the activity of waste tire rubber powder. The activators used include activator A and activator B. The waste tire rubber powder is first swelled in activator A for primary activation to obtain primary activated waste tire rubber powder. The primary activated waste tire rubber powder and activator B are then mixed and stirred for secondary activation. Finally, the waste tire rubber powder is crushed to obtain secondary activated waste tire rubber powder.

[0007] Further, the activator A is a white oil solution of zinc stearate, and the content of zinc stearate is 3wt%-5wt%;

[0008] Furthermore, the activator B is a mixture of styrene, acrylamide, N-allylbenzenesulfonamide, initiator and antioxidant in a weight ratio of 10-20:5-15:1-3:0.1-0.5:1-2.

[0009] Preferably, the waste tire rubber powder is washed with acetone before activation.

[0010] Preferably, the primary activation temperature is 80-90° C. and the time is 3-5 h.

[0011] Preferably, the secondary activation temperature is 170-180° C., the time is 1.5-2.5 h, and the rotation speed is 1000-1200 rpm.

[0012] Preferably, the particle size of the secondary activated waste tire rubber powder is 80 mesh.

[0013] Preferably, the white oil is No. 5 white oil.

[0014] Preferably, the initiator is dicumyl peroxide.

[0015] Preferably, the antioxidant is antioxidant 1010.

[0016] Preferably, the secondary activated waste tire rubber powder is used for asphalt modification.

[0017] Beneficial effects of the present invention:

[0018] The activator for improving the activity of waste tire rubber powder provided by the present invention cleverly adopts the combination of activator A and activator B, and effectively improves the activity of waste tire rubber powder by using two activation processes, wherein the first activation is the swelling activator A, and the second activation is the grafting activator B, which effectively improves the activity of waste tire rubber powder, and the waste tire rubber powder is added into asphalt to prepare modified asphalt, and the needle penetration, ductility, softening point and viscosity indicators of the modified asphalt are all improved.

[0019] The zinc stearate in the activator A of the present invention can significantly improve the needle penetration, which is mainly because the zinc stearate is filled into the molecular network of the waste tire rubber powder as a filler on the one hand, and on the other hand, it acts as an activator to improve the activity of the waste tire rubber powder.

[0020] The N-allylbenzenesulfonamide and acrylamide in the activator B of the present invention synergistically improve the activity of the waste tire rubber powder. This is mainly due to the chemical reaction between the amides of N-allylbenzenesulfonamide and acrylamide and the acid groups in the asphalt. The formed three-dimensional network structure further strengthens the interaction between the waste tire rubber powder and the asphalt. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0022] In the specific implementation manner of the present invention, the waste tire rubber powder was purchased from Jinan Baijin Chemical Technology Co., Ltd., and the particle size was 80 mesh.

[0023] Example 1: (1) 30 g of zinc stearate was dissolved in 970 g of No. 5 white oil to obtain activator A;

[0024] (2) 10 g of styrene, 5 g of acrylamide, 1 g of N-allylbenzenesulfonamide, 0.1-0.5 g of diisopropylbenzene peroxide and 1-2 g of antioxidant 1010 were mixed to obtain activator B;

[0025] (3) After washing 100 g of waste tire rubber powder with acetone, add it to 1000 g of activator A for swelling and perform a primary activation at a temperature of 80 °C for 3 h. Filter to obtain the primary activated waste tire rubber powder. Then, mix 1.4 g of activator B and 100 g of the primary activated waste tire rubber powder and stir. Heat the mixture to 170 °C for a secondary activation at a speed of 1000 rpm for 1.5 h. After cooling, crush the mixture into 80 meshes to obtain the secondary activated waste tire rubber powder.

[0026] Example 2: (1) Dissolve 40 g of zinc stearate in 960 g of No. 5 white oil to obtain activator A;

[0027] (2) 15 g of styrene, 10 g of acrylamide, 2 g of N-allylbenzenesulfonamide, 0.3 g of diisopropylbenzene peroxide and 1-2 g of antioxidant 1010 were mixed to obtain activator B;

[0028] (3) After washing 100 g of waste tire rubber powder with acetone, add it to 1000 g of activator A for swelling and perform a primary activation at a temperature of 85 °C for 4 h. Filter to obtain the primary activated waste tire rubber powder. Then, mix 2.6 g of activator B and 100 g of the primary activated waste tire rubber powder and stir. Heat the mixture to 175 °C for a secondary activation at a speed of 1200 rpm for 2 h. After cooling, crush the mixture into 80 meshes to obtain the secondary activated waste tire rubber powder.

[0029] Example 3: (1) Dissolve 50 g of zinc stearate in 950 g of No. 5 white oil to obtain activator A;

[0030] (2) 20 g of styrene, 15 g of acrylamide, 3 g of N-allylbenzenesulfonamide, 0.5 g of diisopropylbenzene peroxide and 2 g of antioxidant 1010 were mixed to obtain activator B;

[0031] (3) After washing 100 g of waste tire rubber powder with acetone, add it to 1000 g of activator A for swelling and perform a primary activation at a temperature of 90 °C for 5 h. Filter to obtain the primary activated waste tire rubber powder. Then, mix 3.5 g of activator B and 100 g of the primary activated waste tire rubber powder and stir. Heat the mixture to 180 °C and perform a secondary activation at a speed of 1200 rpm for 2.5 h. After cooling, crush the mixture into 80 meshes to obtain the secondary activated waste tire rubber powder.

[0032] Comparative Example 1: (1) 40 g of zinc stearate was dissolved in 960 g of No. 5 white oil to obtain activator A;

[0033] (2) 100 g of waste tire rubber powder was washed with acetone and then added to 1000 g of activator A for swelling. The activation was performed at a temperature of 85°C for 4 h. The activated waste tire rubber powder was filtered to obtain activated waste tire rubber powder.

[0034] Comparative Example 2: (1) 15 g of styrene, 10 g of acrylamide, 2 g of N-allylbenzenesulfonamide, 0.3 g of diisopropylbenzene peroxide and 1-2 g of antioxidant 1010 were uniformly mixed to obtain activator B;

[0035] (2) 100 g of waste tire rubber powder was washed with acetone and mixed with 2.6 g of activator B, and the mixture was heated to 175°C for activation for 2 h at a rotation speed of 1200 rpm. After cooling, the mixture was crushed to 80 mesh to obtain activated waste tire rubber powder.

[0036] Comparative Example 3: (1) 15 g of styrene, 10 g of acrylamide, 2 g of N-allylbenzenesulfonamide, 0.3 g of diisopropylbenzene peroxide and 1-2 g of antioxidant 1010 were uniformly mixed to obtain activator B;

[0037] (2) After washing 100 g of waste tire rubber powder with acetone, add it into 1000 g of No. 5 white oil to swell and perform a primary activation at a temperature of 85 °C for 4 h. Filter to obtain the primary activated waste tire rubber powder. Then, mix 2.6 g of activator B and 100 g of the primary activated waste tire rubber powder and stir. Heat to 175 °C and perform a secondary activation for 2 h at a rotation speed of 1200 rpm. After cooling, crush to 80 mesh to obtain activated waste tire rubber powder.

[0038] Comparative Example 4: (1) 40 g of zinc stearate was dissolved in 960 g of No. 5 white oil to obtain activator A;

[0039] (2) 15 g of styrene, 2 g of N-allylbenzenesulfonamide, 0.3 g of diisopropylbenzene peroxide and 1-2 g of antioxidant 1010 were mixed to obtain activator B;

[0040] (3) After washing 100 g of waste tire rubber powder with acetone, add it to 1000 g of activator A for swelling and perform a primary activation at a temperature of 85 °C for 4 h. Filter to obtain the primary activated waste tire rubber powder. Then, mix 2.6 g of activator B and 100 g of the primary activated waste tire rubber powder and stir. Heat the mixture to 175 °C and perform a secondary activation at a speed of 1200 rpm for 2 h. After cooling, crush the mixture into 80 meshes to obtain the activated waste tire rubber powder.

[0041] Comparative Example 5: (1) Dissolve 40 g of zinc stearate in 960 g of No. 5 white oil to obtain activator A;

[0042] (2) 15 g of styrene, 10 g of acrylamide, 0.3 g of diisopropylbenzene peroxide and 1-2 g of antioxidant 1010 were mixed evenly to obtain activator B;

[0043] (3) After washing 100 g of waste tire rubber powder with acetone, add it to 1000 g of activator A for swelling and perform a primary activation at a temperature of 85 °C for 4 h. Filter to obtain the primary activated waste tire rubber powder. Then, mix 2.6 g of activator B and 100 g of the primary activated waste tire rubber powder and stir. Heat the mixture to 175 °C and perform a secondary activation at a speed of 1200 rpm for 2 h. After cooling, crush the mixture into 80 meshes to obtain the activated waste tire rubber powder.

[0044] Preparation of modified asphalt: Heat 100 g of No. 95 base asphalt to 140°C, then add 20 g of activated waste tire rubber powder prepared in the embodiment and comparative example, continue stirring for 20 minutes, and then high-speed shear at 4000 rpm for 30 minutes to obtain the modified asphalt corresponding to the embodiment and comparative example.

[0045] Performance Test:

[0046] Conventional performance test of asphalt: The penetration, ductility and softening point of the modified asphalt corresponding to the embodiment and the comparative example were tested according to JTG E20-2011, and the results are shown in Table 1; the rotational viscosity of the modified asphalt corresponding to the embodiment and the comparative example was tested using a rotational viscometer, and the results are shown in Table 1.

[0047] Storage stability test: According to JTG E20-2011, 50 g of the modified asphalt corresponding to the embodiment and the comparative example was added into a separation tube, placed at 160°C for 48 hours and then cooled. The softening point difference between the top and bottom asphalt in the separation tube was measured as an evaluation index of the thermal storage stability of the modified asphalt. The results are shown in Table 1.

[0048] Table 1 Performance test results

[0049]

[0050] Note: The control group directly uses waste tire rubber powder to modify the base asphalt.

[0051] Data analysis: From the performance data of Examples 1-3 and the control group, it can be seen that the activator prepared by the present invention can effectively improve the activity of waste tire rubber powder. When it is added to the matrix asphalt, the penetration can be reduced, and the ductility and softening point can be increased. The reduction in penetration is mainly due to the fact that the activated rubber powder does not need to absorb a large amount of light components during the swelling process, so that the modified asphalt is softer and has a higher penetration. The improvement in ductility and softening point is mainly due to the higher surface activity of the waste tire rubber powder after activation, which forms a good interface transition in the modified asphalt system and has better compatibility. It can also be seen from the difference in softening points that even in a high temperature environment, the modified asphalt will not segregate.

[0052] It can be seen from Example 2 and Comparative Examples 1-2 that the activator A and activator B improved by the present invention are indispensable, and the two activations have a certain synergistic effect, which jointly improve the activity of the waste tire rubber powder.

[0053] It can be seen from Example 2 and Comparative Example 3 that the zinc stearate in activator A can significantly improve the needle penetration. This is mainly because the zinc stearate, on the one hand, acts as a filler to fill into the molecular network of the waste tire rubber powder, and on the other hand, acts as an activator to improve the activity of the waste tire rubber powder.

[0054] It can be seen from Example 2 and Comparative Examples 4-5 that N-allylbenzenesulfonamide and acrylamide in activator B synergistically improve the activity of waste tire rubber powder. This is mainly due to the chemical reaction between the amides of N-allylbenzenesulfonamide and acrylamide and the acid groups in asphalt. The formed three-dimensional network structure further strengthens the interaction between waste tire rubber powder and asphalt.

[0055] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. An activation method for improving the activity of waste tire rubber powder, characterized in that: The activators used include activator A and activator B. The waste tire rubber powder is first swelled in the activator A for primary activation to obtain primary activated waste tire rubber powder. The primary activated waste tire rubber powder and the activator B are then mixed and stirred for secondary activation. Finally, the powder is crushed to obtain secondary activated waste tire rubber powder. The activator A is a white oil solution of zinc stearate, and the content of zinc stearate is 3wt%-5wt%; The activator B is a mixture of styrene, acrylamide, N-allylbenzenesulfonamide, initiator and antioxidant in a weight ratio of 10-20:5-15:1-3:0.1-0.5:1-2; Wherein, the temperature of the primary activation is 80-90°C and the time is 3-5h; The secondary activation temperature is 170-180° C., the time is 1.5-2.5 hours, and the rotation speed is 1000-1200 rpm.

2. The activation method for improving the activity of waste tire rubber powder according to claim 1, characterized in that: The waste tire rubber powder is washed with acetone before activation.

3. The activation method for improving the activity of waste tire rubber powder according to claim 1, characterized in that: The particle size of the secondary activated waste tire rubber powder is 80 meshes.

4. The activation method for improving the activity of waste tire rubber powder according to claim 1, characterized in that: The white oil is No. 5 white oil.

5. The activation method for improving the activity of waste tire rubber powder according to claim 1, characterized in that: The initiator is dicumyl peroxide.

6. The activation method for improving the activity of waste tire rubber powder according to claim 1, characterized in that: The antioxidant is antioxidant 1010.

7. The activation method for improving the activity of waste tire rubber powder according to claim 1, characterized in that: The obtained secondary activated waste tire rubber powder is used for asphalt modification.

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