Method for preparing thermoplastic elastomer from waste rubber and waste tires

Abstract

The invention discloses a method for preparing a thermoplastic elastomer from waste rubber and waste tires, which belongs to the technical field of thermoplastic elastomers, and comprises the following steps: (1) pretreatment: crushing waste rubber and / or waste tires to form waste rubber powder, and then pretreating with an alkaline solution; (2) modification of the pretreated rubber powder: carrying out surface plasma activation treatment on the pretreated rubber powder, and then modifying with nano silicon dioxide and a silane coupling agent; and (3) preparation of the thermoplastic elastomer: mixing the modified rubber powder and thermoplastic resin to prepare the thermoplastic elastomer. According to the method for preparing the thermoplastic elastomer from the waste rubber and the waste tires, the tensile strength and hardness of the thermoplastic elastomer can be improved, and the compression set of the thermoplastic elastomer is reduced.

Description

Technical Field

[0001] The invention relates to a method for preparing a thermoplastic elastomer by utilizing waste rubber and waste tires, and belongs to the technical field of thermoplastic elastomers. Background Art

[0002] Thermoplastic elastomer is a new type of polymer material between rubber and resin. It has the elasticity of rubber at room temperature and can be plasticized at high temperature. It is often called the third generation of rubber and is widely used in daily necessities, fitness equipment, rubber-coated products, automotive accessories and other industries.

[0003] As important recycling materials, waste rubber and / or waste tires not only solve the problem of environmental pollution, but also provide a rich source of raw materials for the preparation of thermoplastic elastomers. However, due to the limitations of the properties of waste rubber and / or waste tires themselves, the prepared thermoplastic elastomers perform poorly in elastic recovery and deformation recovery after long-term compression. In addition, the interface bonding ability between waste rubber, waste tires and thermoplastic resins is poor, which also affects the mechanical properties and stability of the thermoplastic elastomers. Summary of the invention

[0004] In order to solve at least one problem existing in the above-mentioned prior art, the present invention provides a method for preparing a thermoplastic elastomer by using waste rubber and waste tires, which can improve the tensile strength and hardness of the thermoplastic elastomer and reduce the compression permanent deformation of the thermoplastic elastomer.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme: a method for preparing a thermoplastic elastomer using waste rubber and waste tires, comprising the following steps: (1) Pretreatment: Waste rubber and / or waste tires are crushed to form waste rubber powder, which is then pretreated with an alkaline solution; (2) Modification of pre-treated rubber powder: The surface of the pre-treated rubber powder is activated by plasma, and then modified with nano-silica and silane coupling agent; (3) Preparation of thermoplastic elastomer: Thermoplastic elastomer is prepared by mixing modified rubber powder with thermoplastic resin.

[0006] Preferably, the method for preparing a thermoplastic elastomer using waste rubber and waste tires comprises the following specific steps: (1) Pretreatment: Cut waste rubber and waste tires into rubber pieces of 0.5-1 cm in size, and then grind them into waste rubber powder with a particle size of not less than 500 mesh, and then soak them in an alkaline solution for 3-5 hours, filter them, wash them with water, and dry them to obtain pretreated rubber powder; (2) Modification of pretreated rubber powder: The pretreated rubber powder is first surface activated by plasma, and the activated rubber powder, nano-silica, silane coupling agent, and 95% ethanol are mixed and dispersed by ball milling. Then, under high-speed homogenization conditions, the reaction is first carried out at a temperature of 65-75°C, and then the temperature is raised to 125-135°C for curing. The mixture is cooled to room temperature to obtain modified rubber powder. (3) Preparation of thermoplastic elastomer: The modified rubber powder and thermoplastic resin are mixed at a mixing temperature of 170-185°C for 15-30 min, then cooled to 110-130°C and kept at this temperature for 1-2 h before being extruded and granulated by a twin-screw extruder to obtain a thermoplastic elastomer.

[0007] Preferably, in step (1), the particle size of the waste rubber powder is 500-600 mesh.

[0008] Preferably, in step (1), the temperature at which the waste rubber powder is immersed in the alkaline solution is 40-50° C., and the stirring speed is 200-300 rpm.

[0009] Preferably, in step (1), the alkaline solution is one of sodium hydroxide solution, potassium hydroxide solution or sodium carbonate solution.

[0010] Preferably, the solid content of the sodium hydroxide solution, potassium hydroxide solution or sodium carbonate solution is 8-15%.

[0011] Preferably, in step (2), the plasma conditions are: the plasma radio frequency power is 80-100 W, the time is 3-4 min; and the plasma gas is one of oxygen or air.

[0012] Preferably, in step (2), the mass ratio of the activated rubber powder to nano-silicon dioxide, silane coupling agent, and 95% ethanol is 100:2:0.75:40.

[0013] Preferably, in step (2), the silane coupling agent is one of silane coupling agent KH560 or silane coupling agent KH570.

[0014] Preferably, in step (2), the ball milling speed is 300-400 rpm, and the ball milling time is 20-30 min.

[0015] Preferably, in step (2), the ball-milled material is first subjected to a reaction treatment at a temperature of 65-75° C. for 50-60 min at a high-speed homogenizer speed of 1500-2000 rpm, and then heated to 125-135° C. for curing treatment for 30-40 min.

[0016] Preferably, in step (2), the nano-silicon dioxide is preferably prepared by a gas phase reaction.

[0017] Preferably, in step (3), the mass ratio of the modified rubber powder to the thermoplastic resin is (20-35):(4-6).

[0018] Preferably, in step (3), the particle size of the thermoplastic resin is 200-300 mesh.

[0019] Preferably, in step (3), the thermoplastic resin is one or more of polypropylene, polyethylene, propylene-ethylene copolymer, polystyrene, etc., and has a melting point lower than 200°C.

[0020] Preferably, in step (3), auxiliary additives may be added to the modified rubber powder and thermoplastic resin, and the auxiliary additives account for 3-12% of the mass of the modified rubber powder.

[0021] Preferably, the auxiliary additives include plasticizers, antioxidants and vulcanizers.

[0022] Preferably, the auxiliary additives may also include one or more of internal lubricants, fillers, stabilizers, modifiers, and the like.

[0023] The beneficial effects of the present invention are as follows: the method for preparing a thermoplastic elastomer of the present invention comprises the following steps: firstly, the waste rubber and / or waste tires are crushed to a particle size of not less than 500 meshes, the surface area of ​​the waste rubber powder surface treated by the alkaline solution is increased, and the looseness and roughness of the surface of the waste rubber powder are improved; then, the surface of the pretreated rubber powder is activated by plasma, so that the compatibility and bonding force of the rubber powder surface are improved; meanwhile, the looseness and roughness of the surface of the pretreated rubber powder have a large contact area, so that the activation performance of the rubber powder surface is increased, the modification effect of the rubber powder is improved, and the bonding force between the modified rubber powder and the thermoplastic resin is effectively enhanced; and the preparation method of the present invention jointly modifies the activated rubber powder by nano-silicon dioxide and a silane coupling agent, so that the interface bonding ability between the modified rubber powder and the thermoplastic resin is further enhanced, and the elasticity and elastic deformation of the modified rubber powder are improved, so that the thermoplastic elastomer prepared by combining the modified rubber powder with the thermoplastic resin has excellent mechanical properties and stability. DETAILED DESCRIPTION

[0024] The following is a clear and complete description of the technical solutions in the implementation of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents, instruments, and components used, they are all conventional products that can be purchased commercially.

[0025] Example 1 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, the specific steps are as follows: (1) Cut waste rubber and waste tires into rubber pieces of 0.5-1 cm in size, and then grind them into 1 kg of waste rubber powder with a particle size of 500-600 mesh, and then soak them in 10% sodium hydroxide solution for 4 h at a temperature of 40°C and a stirring speed of 250 rpm, filter and wash them with water, and dry them at a temperature of 45°C to obtain pretreated rubber powder; (2) The pretreated rubber powder was first surface activated by plasma, the plasma radio frequency power was 80W, the time was 4 minutes, the plasma gas was oxygen, 600g of the activated rubber powder, 12g of nano-silicon dioxide, 4.5g of silane coupling agent KH560, and 240g of 95% ethanol were ball-milled and dispersed, the ball-milling speed was 350rpm, the ball-milling time was 25min, and then under the condition of high-speed homogenization at a speed of 1800rpm, the reaction was first carried out at a temperature of 70°C for 50min, then the temperature was raised to 130°C for curing for 30min, and then cooled to room temperature to obtain modified rubber powder; wherein the nano-silicon dioxide was prepared by gas phase reaction; (3) 500 g of modified rubber powder, 100 g of polypropylene particles with a particle size of 200-300 mesh, 5 g of plasticizer distearate glyceryl (DSG), 2.5 g of antioxidant 1010 and 7.5 g of vulcanizing agent silane coupling agent Si69 were mixed at a mixing temperature of 185 °C for 15 min, then cooled to 120 °C and kept at this temperature for 1 h before being extruded and granulated by a twin-screw extruder to obtain a thermoplastic elastomer.

[0026] Example 2 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, the specific steps are as follows: (1) Cut waste rubber and waste tires into rubber pieces of 0.5-1 cm in size, and then grind them into 1 kg of waste rubber powder with a particle size of 500-600 mesh, and then soak them in 8% sodium hydroxide solution for 3 h at a soaking temperature of 45°C and a stirring speed of 200 rpm, filter and wash them with water, and dry them at a temperature of 45°C to obtain pretreated rubber powder; (2) The pretreated rubber powder was first surface activated by plasma, the plasma radio frequency power was 90W, the time was 3 minutes, the plasma gas was oxygen, 500g of activated rubber powder, 10g of nano-silicon dioxide, 3.75g of silane coupling agent KH570, and 200g of 95% ethanol were ball-milled and dispersed, the ball-milling speed was 400rpm, the ball-milling time was 20min, and then under the condition of high-speed homogenization at a speed of 1500rpm, the reaction treatment was first carried out at a temperature of 60°C for 60min, then the temperature was raised to 125°C for curing treatment for 40min, and then cooled to room temperature to obtain modified rubber powder; wherein the nano-silicon dioxide was prepared by gas phase reaction; (3) 350 g of modified rubber powder, 60 g of polypropylene particles with a particle size of 200-300 mesh, 5.2 g of plasticizer distearate glyceryl (DSG), 2.8 g of antioxidant 1010 and 7 g of vulcanizing agent silane coupling agent Si69 were mixed at a mixing temperature of 180 °C for 20 min, then cooled to 110 °C and kept at this temperature for 2 h before being extruded and granulated by a twin-screw extruder to obtain a thermoplastic elastomer.

[0027] Example 3 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, the specific steps are as follows: (1) Cut waste rubber and waste tires into rubber pieces of 0.5-1 cm in size, and then grind them into 1 kg of waste rubber powder with a particle size of 500-600 mesh, and then soak them in 15% sodium carbonate solution for 5 h at a soaking temperature of 50°C and a stirring speed of 300 rpm, filter and wash them with water, and dry them at a temperature of 45°C to obtain pretreated rubber powder; (2) The pretreated rubber powder was first surface activated by plasma, the plasma radio frequency power was 100 W, the time was 3.5 min, the plasma gas was oxygen, 700 g of the activated rubber powder, 14 g of nano-silicon dioxide, 5.25 g of silane coupling agent KH560, and 280 g of 95% ethanol were ball-milled for mixing and dispersion, the ball-milling speed was 300 rpm, the ball-milling time was 30 min, and then under the condition of high-speed homogenization at a speed of 2000 rpm, the reaction was first carried out at a temperature of 75°C for 60 min, then the temperature was raised to 135°C for curing for 40 min, and then cooled to room temperature to obtain modified rubber powder; wherein the nano-silicon dioxide was prepared by gas phase reaction; (3) 400 g of modified rubber powder, 80 g of polypropylene particles with a particle size of 200-300 mesh, 6 g of plasticizer distearate glyceryl (DSG), 4 g of antioxidant 1010 and 6 g of vulcanizing agent silane coupling agent Si69 were mixed at a mixing temperature of 170 °C for 30 min, then cooled to 130 °C and kept at this temperature for 1 h before being extruded and granulated by a twin-screw extruder to obtain a thermoplastic elastomer.

[0028] Example 4 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, the specific steps are as follows: (1) Cut waste rubber and waste tires into rubber pieces of 0.5-1 cm in size, and then grind them into 1 kg of waste rubber powder with a particle size of not less than 500 meshes, and then soak them in 10% sodium hydroxide solution for 5 h at a soaking temperature of 40°C and a stirring speed of 250 rpm, filter and wash with water, and dry them at a temperature of 45°C to obtain pretreated rubber powder; (2) The pretreated rubber powder was first surface activated by plasma, the plasma radio frequency power was 80W, the time was 3 minutes, the plasma gas was air, 700g of activated rubber powder, 14g of nano-silicon dioxide, 5.25g of silane coupling agent KH560, and 280g of 95% ethanol were ball-milled and dispersed, the ball-milling speed was 350rpm, the ball-milling time was 20min, and then under the condition of high-speed homogenization at a speed of 150rpm, the reaction treatment was first carried out at a temperature of 75°C for 50min, and then the temperature was raised to 125°C for curing treatment for 30min, and then cooled to room temperature to obtain modified rubber powder; wherein the nano-silicon dioxide was prepared by gas phase reaction; (3) 600 g of modified rubber powder, 120 g of polyethylene particles with a particle size of 200-300 mesh, 4.8 g of plasticizer distearate glyceryl (DSG), 3 g of antioxidant 1010, 6 g of vulcanizer silane coupling agent Si69, and 9 g of filler talc were mixed at a mixing temperature of 180 °C for 30 min, then cooled to 110 °C and kept warm for 1.5 h before being extruded and granulated by a twin-screw extruder to obtain a thermoplastic elastomer.

[0029] Example 5 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, the specific steps are as follows: (1) Cut waste rubber and waste tires into rubber pieces of 0.5-1 cm in size, and then grind them into 1 kg of waste rubber powder with a particle size of 500-600 mesh, and then soak them in 10% sodium hydroxide solution for 5 h at a temperature of 40°C and a stirring speed of 300 rpm, filter and wash them with water, and dry them at a temperature of 45°C to obtain pretreated rubber powder; (2) The pretreated rubber powder was first surface activated by plasma, the plasma radio frequency power was 90W, the time was 3 minutes, the plasma gas was air, 700g of activated rubber powder, 14g of nano-silicon dioxide, 5.25g of silane coupling agent KH570, and 280g of 95% ethanol were ball-milled and mixed and dispersed, the ball-milling speed was 350rpm, the ball-milling time was 20min, and then under the condition of high-speed homogenization at a speed of 150rpm, the reaction treatment was first carried out at a temperature of 75°C for 50min, and then the temperature was raised to 125°C for curing treatment for 30min, and then cooled to room temperature to obtain modified rubber powder; wherein the nano-silicon dioxide was prepared by gas phase reaction; (3) 500 g of modified rubber powder, 80 g of polystyrene particles with a particle size of 200-300 mesh, 4.8 g of plasticizer distearate glyceryl (DSG), 3 g of antioxidant 1010, 7.5 g of vulcanizer silane coupling agent Si69, and 10 g of stabilizer liquid phosphite were mixed at a mixing temperature of 180 °C for 30 min, then cooled to 110 °C and kept warm for 1.5 h before being extruded and granulated by a twin-screw extruder to obtain a thermoplastic elastomer.

[0030] The liquid phosphite of this embodiment is a carbon-based 4,4-diisopropyl-fatty alcohol-phosphate chelate polymer.

[0031] Example 6 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, which is different from Example 2 in that the nano-silicon dioxide used in step (2) is prepared by a precipitation reaction; the rest is exactly the same.

[0032] Example 7 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, which is different from Example 2 in that the nano-silicon dioxide used in step (2) is prepared by a sol-gel reaction; the rest is exactly the same.

[0033] Comparative Example 1 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, which differs from Example 2 in that: Step (1): the waste rubber and waste tires are cut into rubber pieces of 0.5-1 cm in size, and then crushed into 1 kg of waste rubber powder with a particle size of 300-400 mesh, and then soaked in 8% sodium hydroxide solution for 3 h, the soaking temperature is 45° C., the stirring speed is 200 rpm, filtered and washed with water, and dried at a temperature of 45° C. to obtain pretreated rubber powder; the rest is exactly the same.

[0034] Comparative Example 2 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, which differs from Example 2 in that: Step (1): shearing the waste rubber and waste tires into rubber pieces of 0.5-1 cm in size, and then crushing them into 1 kg of waste rubber powder with a particle size of 500-600 mesh, and then soaking them in pure water for 3 hours at a soaking temperature of 45°C and a stirring speed of 200 rpm, filtering, and drying at a temperature of 45°C to obtain pretreated rubber powder; Step (2) does not use an alkaline solution to treat the waste rubber powder; the rest is exactly the same.

[0035] Comparative Example 3 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, which is different from Example 2 in that: in step (2), 500 g of pretreated rubber powder, 10 g of nano-silicon dioxide, 3.75 g of silane coupling agent KH570, and 200 g of 95% ethanol are ball-milled for mixing and dispersion, the ball-milling speed is 400 rpm, and the ball-milling time is 20 min. Then, under high-speed homogenization conditions with a speed of 1500 rpm, the mixture is first reacted at 60° C. for 60 min, then heated to 125° C. for curing for 40 min, and cooled to room temperature to obtain modified rubber powder; wherein the nano-silicon dioxide is prepared by gas phase reaction; in step (2), the pretreated rubber powder is not activated; and the rest is exactly the same.

[0036] Comparative Example 4 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, which is different from Example 2 in that: (2) the pretreated rubber powder is first surface activated by plasma, the plasma radio frequency power is 90 W, the time is 3 minutes, the plasma gas is oxygen, 500g of the activated rubber powder, 10g of nano-silicon dioxide, and 200g of 95% ethanol are ball-milled and dispersed, the ball milling speed is 400rpm, and the ball milling time is 20min. Then, under high-speed homogenization conditions with a speed of 1500rpm, the reaction treatment is first carried out at a temperature of 60°C for 60min, then the temperature is raised to 125°C for curing treatment for 40min, and then cooled to room temperature to obtain modified rubber powder; wherein the nano-silicon dioxide is prepared by gas phase reaction; the silane coupling agent KH570 is not used in step (2); and the rest is exactly the same.

[0037] Comparative Example 5 A method for preparing a thermoplastic elastomer using waste rubber and waste tires, which is different from Example 2 in that: (2) the pretreated rubber powder is first surface activated by plasma, the plasma radio frequency power is 90 W, the time is 3 minutes, the plasma gas is oxygen, 500g of the activated rubber powder, 3.75g of silane coupling agent KH570, and 200g of 95% ethanol are ball-milled for mixing and dispersion, the ball-milling speed is 400rpm, and the ball-milling time is 20min. Then, under high-speed homogenization conditions with a speed of 1500rpm, the reaction is first carried out at a temperature of 60°C for 60min, then the temperature is raised to 125°C for curing for 40min, and then cooled to room temperature to obtain modified rubber powder; step (2) does not use nano-silicon dioxide; the rest is exactly the same.

[0038] The thermoplastic elastomers prepared in the above Examples 1 to 7 and Comparative Examples 1 to 5 were molded into sheets at 180° C. for 60 minutes and tested according to the following method. The test results are shown in Table 1.

[0039] (1) Conduct tensile test according to GB / T528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber; (2) Hardness test according to GB / T531.1-2008 Vulcanized rubber or thermoplastic rubber indentation hardness test method (3) Compression set test is carried out according to GB / T7759-1996 Determination of compression set of vulcanized rubber and thermoplastic rubber at room temperature, high temperature and low temperature.

[0040] Table 1

[0041] As can be seen from Table 1 above, the thermoplastic elastomers prepared from waste rubber and waste tires in Examples 1 to 7 of the present invention have greater hardness, greater tensile strength, higher elongation at break, greater 300% tensile stress, and lower compression permanent deformation at -40°C, room temperature and 200°C, indicating that the modified rubber powder obtained from waste rubber and / or waste tires in the present invention has good compatibility with the thermoplastic resin, effectively improving the interfacial bonding force between the modified rubber powder and the thermoplastic resin, and thus the tensile strength and hardness of the thermoplastic elastomer obtained by the preparation method of the present invention are improved, the compression permanent deformation is reduced, and the thermoplastic elastomer has excellent mechanical properties and stability, effectively solving the problems in the prior art that the thermoplastic elastomer prepared from waste rubber and / or waste tires has poor elastic recovery and deformation recovery after long-term compression, and the interface bonding ability between waste rubber and waste tires and thermoplastic resin is poor.

[0042] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit and essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0043] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a thermoplastic elastomer using waste rubber and waste tires, characterized in that: The following steps are involved: (1) Pretreatment: Waste rubber and / or waste tires are crushed to form waste rubber powder with a size of not less than 500 mesh, and then pretreated with an alkaline solution to obtain pretreated waste rubber powder; (2) Modification of pretreated rubber powder: The surface of the pretreated rubber powder is subjected to plasma activation treatment, and then modified with nano-silica and silane coupling agent to obtain modified rubber powder; (3) Preparation of thermoplastic elastomer: Thermoplastic elastomer is prepared by mixing modified rubber powder with thermoplastic resin.

2. The method for preparing a thermoplastic elastomer using waste rubber and waste tires according to claim 1, characterized in that: The specific steps are as follows: (1) Pretreatment: Cut waste rubber and waste tires into rubber pieces of 0.5-1 cm in size, and then grind them into waste rubber powder with a particle size of not less than 500 mesh, and then soak them in an alkaline solution for 3-5 hours, filter them, wash them with water, and dry them to obtain pretreated rubber powder; (2) Modification of pretreated rubber powder: The pretreated rubber powder is first surface activated by plasma, and the activated rubber powder, nano-silica, silane coupling agent, and 95% ethanol are mixed and dispersed by ball milling. Then, under high-speed homogenization conditions, the reaction is first carried out at a temperature of 65-75°C, and then the temperature is raised to 125-135°C for curing. The mixture is cooled to room temperature to obtain modified rubber powder. (3) Preparation of thermoplastic elastomer: Modified rubber powder, thermoplastic resin and auxiliary additives including plasticizer, antioxidant and vulcanizer are mixed at a temperature of 170-185°C for 15-30 min. The mixture is then cooled to 110-130°C and kept at this temperature for 1-2 h before being extruded and granulated by a twin-screw extruder to obtain a thermoplastic elastomer.

3. The method for preparing a thermoplastic elastomer using waste rubber and waste tires according to claim 1 or 2, characterized in that: The particle size of the waste rubber powder is 500-600 meshes.

4. The method for preparing a thermoplastic elastomer using waste rubber and waste tires according to claim 2, characterized in that: In step (1), the temperature of soaking the waste rubber powder in the alkaline solution is 40-50° C., and the stirring speed is 200-300 rpm; the alkaline solution is one of sodium hydroxide solution, potassium hydroxide solution or sodium carbonate solution.

5. The method for preparing a thermoplastic elastomer using waste rubber and waste tires according to claim 2, characterized in that: In step (2), the plasma conditions are as follows: the plasma radio frequency power is 80-100 W, the time is 3-4 min; and the plasma gas is one of oxygen or air.

6. The method for preparing a thermoplastic elastomer using waste rubber and waste tires according to claim 1 or 2, characterized in that: In step (2), the nano-silicon dioxide is preferably prepared by a gas phase reaction.

7. The method for preparing a thermoplastic elastomer using waste rubber and waste tires according to claim 2, characterized in that: In step (2), the mass ratio of the activated rubber powder to nano-silicon dioxide, silane coupling agent, and 95% ethanol is 100:2:0.75:40; the silane coupling agent is one of silane coupling agent KH560 or silane coupling agent KH570.

8. The method for preparing a thermoplastic elastomer using waste rubber and waste tires according to claim 2, characterized in that: In step (2), the ball milling speed is 300-400 rpm, and the ball milling time is 20-30 min; The ball-milled material is subjected to a high-speed homogenization process at a speed of 1500-2000 rpm: firstly subjected to a reaction treatment at a temperature of 65-75°C for 50-60 min, and then subjected to a curing treatment at 125-135°C for 30-40 min.

9. The method for preparing a thermoplastic elastomer using waste rubber and waste tires according to claim 2, characterized in that: In step (2), the mass ratio of the modified rubber powder to the thermoplastic resin is (20-35):(4-6); The auxiliary additive is 3-12% of the mass of the modified rubber powder; The auxiliary additives also include one or more of internal lubricants, fillers, stabilizers, and modifiers.

10. The method for preparing thermoplastic elastomer by using waste rubber and waste tires according to claim 2, characterized in that: The thermoplastic resin is one or more of polypropylene, polyethylene, polystyrene or propylene-ethylene copolymer, and has a melting point lower than 200°C.

Images