Process for manufacturing conveyor belt by recycling polytetrafluoroethylene

Abstract

The invention relates to the field of high polymer material recycling, in particular to a technology for manufacturing a conveyor belt by recycling polytetrafluoroethylene. According to the process, the recycled polytetrafluoroethylene material is classified and collected according to sources and the like, impurities are removed through magnetic separation and electrostatic separation, and then microwave-assisted cleaning and activation are performed; then, a bio-based additive, a degradable polymer, a photocatalytic self-cleaning material and the like are adopted for modification treatment, so that the multi-aspect performance of the material is improved; then, the material is processed into the shape of a conveyor belt through a water-assisted injection molding or hot press molding process, and after molding, post-treatment is carried out through plant extract coating protection, recoverable and easy-to-disassemble design. The process is suitable for the requirements of conveyor belts in multiple fields, resource recycling is achieved, environmental protection and economic benefits are achieved, and the manufactured conveyor belt is excellent in performance and can meet the requirements of different working conditions.

Description

Technical Field

[0001] The invention relates to the field of polymer material recycling, in particular to a process for recycling polytetrafluoroethylene to make a conveyor belt. Background Art

[0002] Polytetrafluoroethylene (PTFE), commonly known as "Teflon", is widely used in chemical, mechanical, electronic, aerospace and other fields due to its excellent high temperature resistance, corrosion resistance, low friction coefficient and good electrical insulation. However, the treatment of PTFE waste has always been a difficult problem. Due to its stable chemical properties, it is very difficult to degrade naturally. Traditional treatment methods such as landfill and incineration not only occupy land resources, but also may cause environmental pollution.

[0003] At present, there are relatively few technologies for recycling PTFE waste, and most of them focus on crushing it and adding it to other materials as fillers, which has low added value. How to efficiently and environmentally recycle waste PTFE and prepare it into products with practical value is a technical problem that needs to be solved in this field.

[0004] As an important industrial conveying equipment, conveyor belts are widely used in logistics, food, medicine and other industries. High-performance conveyor belts need to have properties such as wear resistance, corrosion resistance, and anti-adhesion. The excellent properties of PTFE material itself make it very suitable for manufacturing high-performance conveyor belts in theory. Therefore, developing a process for preparing high-performance conveyor belts using recycled PTFE can not only solve the problem of PTFE waste disposal, but also provide a new environmentally friendly material option for the conveyor belt industry. Summary of the invention

[0005] The present invention provides a process for recycling polytetrafluoroethylene to produce a conveyor belt. The process can effectively recycle waste polytetrafluoroethylene materials, improve the performance of recycled materials through innovative pretreatment, modification, molding and post-treatment processes, and produce a conveyor belt that meets actual use needs. At the same time, it pays attention to environmental protection and sustainable development, reduces the impact on the environment, and realizes the recycling of resources.

[0006] A process for recycling polytetrafluoroethylene to make a conveyor belt, comprising: Recycling material pre-processing: Classification collection: Collect various types of waste polytetrafluoroethylene products and classify them according to their sources, usage conditions and material characteristics.

[0007] Impurity removal: The impurities in the recycled materials are removed by combining magnetic separation and electrostatic separation. The magnetic field intensity of the magnetic separation equipment is between 0.1 - 1T, which can effectively adsorb and remove magnetic metal impurities such as iron filings and screws; the electric field intensity of the electrostatic separation device is between 1 - 10 kV / cm, which can separate non-PTFE foreign matters such as plastic debris and fibers attached to the material surface due to electrostatic adsorption.

[0008] Microwave-assisted cleaning and activation: The recycled materials after impurity removal are placed in a microwave treatment device, and a cleaning medium composed of water and biodegradable surfactant is added. Utilizing the thermal and non-thermal effects of microwaves, the oil stains and chemical residues on the material surface are removed, and the material surface is activated. After cleaning, the cleaning medium is separated by filtration, centrifugation, etc., and then the material is treated by low-temperature vacuum drying to avoid adverse effects of high temperature on the material properties.

[0009] Modification treatment of recycled materials: Modification with bio-based additives: Lignin nanoparticles are selected as bio-based additives, and their particle size ranges from 50 - 500 nm. The lignin nanoparticles are added to the pretreated materials at a ratio of 3% - 8% of the total mass of the recycled PTFE, and are thoroughly mixed evenly by a high-speed mixer. The lignin nanoparticles can enhance the mechanical properties of the conveyor belt, endow it with anti-ultraviolet ability, and since lignin is biodegradable, it meets the environmental protection requirements.

[0010] Modification by blending with biodegradable polymers: Polylactic acid is selected as the biodegradable polymer material, and is added to the recycled PTFE together with the recycled PTFE at a ratio of 10% - 20% of the total mass of the blend. Blending is carried out in the temperature range of 180 - 250 °C to make the polylactic acid evenly dispersed in the PTFE matrix, improving the processing performance of the material and simultaneously realizing the partial biodegradable function after the conveyor belt is discarded.

[0011] Photocatalytic self-cleaning modification: A composite powder of nano-titanium dioxide and graphene is prepared as the photocatalytic self-cleaning modifier, and the ratio of the two is 1:1 - 3:1. This composite powder is added to the material at a ratio of 2% - 6% of the total mass of the recycled PTFE, and ultrasonic dispersion, ball milling and other processes are used to ensure its uniform dispersion. Under light illumination conditions, the photocatalytic effect of nano-titanium dioxide can decompose the pollutants on the surface of the conveyor belt, realizing the self-cleaning function.

[0012] Specific forming process: Water-assisted injection molding: For the conveyor belt shape and structure suitable for this process, the modified material is added to the injection molding machine barrel and heated to 280 - 330 °C to make it molten. After injecting into the mold cavity, a high-pressure water of 10 - 30 MPa is injected to push the melt to fill the mold. The discharged water can be recycled after filtration, purification and other treatments. This molding method can improve the surface quality of the product and reduce defects.

[0013] Hot pressing molding and waste heat recovery and utilization: If the hot pressing molding process is adopted, the modified material is placed in the hot pressing mold and hot pressing molding is carried out under the conditions of a hot pressing temperature of 300 - 360 °C, a pressure of 15 - 25 MPa and a pressure holding time of 30 - 90 minutes. After molding, the waste heat dissipated from the surface of the mold and equipment is collected by a heat exchanger. The heat exchanger is made of copper alloy material and is internally provided with a spiral circulating water channel. The recovered hot water can be used to preheat the next batch of materials or for workshop heating, improving the energy utilization rate.

[0014] Post-treatment and sustainable design: Plant extract coating protection: Rosemary extract with antibacterial and antioxidant functions is mixed with a water-based film-forming agent (such as water-based acrylic resin) in a certain proportion, and appropriate additives are added to make a water-based protective coating. The coating is applied to the conveyor belt by spraying or dipping, and the coating thickness is controlled between 10 - 50 μm, which can inhibit the growth of microorganisms and delay the aging of the conveyor belt.

[0015] Recyclable and easy-to-disassemble design: When designing the conveyor belt structure, a snap connection or a pluggable fixed structure is adopted, and connection means such as glue and welding that are difficult to separate are avoided. In this way, after the conveyor belt is scrapped, each component can be easily disassembled and classified for recycling, improving the resource recycling rate.

[0016] Compared with the prior art, the advantages of the present invention are as follows: Resource recycling and utilization: The present invention effectively solves the problem of the treatment of polytetrafluoroethylene waste, realizes the efficient recycling and reuse of resources, reduces the dependence on primary resources, and reduces the production cost; Performance improvement: Through various modification methods, the mechanical properties, processing properties, anti-ultraviolet properties, self-cleaning properties, etc. of the recycled polytetrafluoroethylene material are significantly improved, and the produced conveyor belt can meet the usage requirements of different industries; Environmental protection and sustainability: The use of biodegradable additives and polymer materials, combined with measures such as waste heat recovery and utilization and easy-to-disassemble design, reduces the environmental impact of the entire process, conforms to the concept of green development. During the whole life cycle of the product, the generation of waste is reduced, and the recycling of resources is realized. Specific implementation manners

[0017] In one embodiment, a specific implementation method of a polytetrafluoroethylene recycling process for making a conveyor belt in a parcel sorting scenario in the logistics and express delivery industry is provided, including: Implementation background: In the parcel sorting center of the logistics and express delivery industry, the conveyor belt needs to run for a long time and at high intensity, carrying a large number of parcels of different weights and shapes for rapid sorting and transportation every day. This requires the conveyor belt to have good wear resistance to cope with the frequent friction of the parcels; it must have high strength and toughness to prevent damage under the pressure of heavy objects; at the same time, it must also have a certain degree of dirt resistance to facilitate cleaning and maintenance. Considering the concept of environmental protection and sustainable development, using recycled materials to make conveyor belts that meet the above requirements has become an ideal choice.

[0018] Recycling material pre-processing: Impurity removal: Magnetic separation: The classified recycled polytetrafluoroethylene materials are passed through the magnetic separation equipment in turn, and the magnetic field strength of the magnetic separation equipment is set to 0.6T. At this intensity, magnetic metal impurities such as iron nails and metal gaskets mixed in the material are effectively removed. Most of these impurities come from the assembly and fixing parts of the previous equipment.

[0019] Electrostatic separation: Next, the magnetically separated material is sent to the electrostatic separation device, and the electric field strength is adjusted to 6kV / cm. With this electric field strength, non-PTFE foreign matter such as plastic film fragments and fiber fluff that are attached to the surface of the PTFE material due to electrostatic adsorption is successfully separated, significantly improving the purity of the material.

[0020] Microwave assisted cleaning and activation: Preparation of cleaning medium: Weigh the alkyl glycoside surfactant and water in a mass ratio of 1:70, pour the water into a stainless steel container, then slowly add the alkyl glycoside surfactant, and stir with a stainless steel stirring rod at a speed of about 70 revolutions per minute for 7 minutes to make a uniform and transparent mixed cleaning medium.

[0021] Microwave cleaning and activation: Put the recycled polytetrafluoroethylene material after impurities are removed into the microwave processing equipment, add an appropriate amount of the above cleaning medium and turn on the equipment. The cleaning medium is heated by microwave radiation, and under the action of thermal effect, impurities such as dust, stains and possible residual chemicals on the surface of the material are effectively dissolved and removed. At the same time, the non-thermal effect of microwaves promotes the generation of more active sites on the surface of polytetrafluoroethylene materials. After cleaning, the cleaning medium is separated from the material by centrifugation, and then the material is placed in a low-temperature vacuum drying oven and dried at 45°C for 3 hours to ensure that the material is dry and the performance is not damaged.

[0022] Modification of recycled materials: Bio-based additive modification: Addition of lignin nanoparticles: Lignin nanoparticles with a particle size of 300 nm are selected and added to the pretreated material at a ratio of 6% of the total mass of the recycled polytetrafluoroethylene.

[0023] Mixing operation: Put the two into a high-speed mixer, set the rotation speed to 1200 revolutions per minute, and the mixing time to 25 minutes, so that the lignin nanoparticles are evenly dispersed in the polytetrafluoroethylene matrix. After this modification, it is expected to enhance the wear resistance and tensile resistance of the conveyor belt to cope with the frequent friction and pulling during package sorting, and at the same time endow it with a certain ability to resist ultraviolet rays to cope with the possible sunlight in the logistics site and delay the aging of the material.

[0024] Degradable polymer blending modification: Polylactic acid blending: Select polylactic acid as the degradable polymer material and add it to the twin-screw extruder together with the recycled polytetrafluoroethylene at a ratio of 18% of the total mass of the blend.

[0025] Blending operation: In the twin-screw extruder, adjust the temperature of each heating section to be in the range of 200 - 240 °C. Relying on the shearing and kneading action of the screw, promote the uniform dispersion of polylactic acid in the polytetrafluoroethylene matrix. This modification helps to optimize the processing performance of the material, making the subsequent forming smoother. And after the conveyor belt is discarded, polylactic acid can be gradually degraded in the natural environment, meeting the environmental protection requirements of the enterprise.

[0026] Photocatalytic self-cleaning modification: Addition of composite powder: Prepare a composite powder of nano-titanium dioxide and graphene (the ratio of the two is 3:1) and add it to the material at a ratio of 5% of the total mass of the recycled polytetrafluoroethylene.

[0027] Dispersion treatment: Through 40 minutes of ultrasonic dispersion and then combined with 1.5 hours of ball milling, ensure the uniform dispersion of the composite powder in the material and prevent agglomeration. After this treatment, during the use of the conveyor belt, when the surface is contaminated with dust, package stains and other pollutants, under the natural light in the logistics site, nano-titanium dioxide can play a photocatalytic role and decompose these pollutants into small molecule substances such as carbon dioxide and water, achieving the self-cleaning function of the conveyor belt and reducing the frequency of manual cleaning.

[0028] Specific forming process: Considering that the shape and structure of the conveyor belt are relatively regular, and the advantages of the hot pressing forming process in making large and regular structure products, as well as the convenience of implementing waste heat recovery, it is decided to adopt the hot pressing forming process.

[0029] Hot pressing operation: Place the modified recycled polytetrafluoroethylene material in a special hot pressing mold, heat the mold through a heating plate, control the hot pressing temperature at about 330°C, set the pressure to 20MPa, and hold the pressure for 60 minutes, so that the material is heated and pressed in the mold and gradually formed into a conveyor belt shape. During the hot pressing process, strictly control the stability of temperature and pressure and the accuracy of holding time to ensure that the molecular chains inside the material are fully moved and cross-linked, so as to obtain good mechanical properties and dimensional stability.

[0030] Waste heat recovery and utilization: After the hot pressing process is completed, a large amount of heat will be emitted from the mold and equipment surface. The waste heat is collected by heat exchangers installed around the hot pressing equipment. The heat exchanger is made of copper alloy material, and a spiral circulating water channel (tube diameter is 6mm, pitch is 12mm) is set inside, which can efficiently collect heat and transfer it to the circulating water. The heated circulating water is transported to the storage tank for storage, which can be used to preheat the next batch of materials to be hot-pressed, reduce the heating energy consumption during hot-pressing, or be used for heating the workshop in winter to improve the comprehensive utilization rate of energy.

[0031] Post-processing and sustainable design: Plant extract coating protection: Coating preparation: Green tea extract with antibacterial and antioxidant functions is mixed with water-based polyurethane resin in a mass ratio of 1:4, and an appropriate amount of thickener (0.6% of the total mass) and defoamer (0.3% of the total mass) are added. After fully stirring, a water-based protective coating is prepared.

[0032] Coating application: Apply the water-based protective coating to the formed conveyor belt by spraying, control the coating thickness to about 40μm, make the coating evenly cover the surface of the conveyor belt, inhibit the growth of microorganisms, reduce the performance degradation of the conveyor belt caused by microbial action, and delay the aging effect of the conveyor belt due to long-term exposure to complex logistics environment.

[0033] Recyclable and easy-to-disassemble design: In the structural design of the conveyor belt, a pluggable fixed structure is adopted. A set of slots and latches are set every 40 cm on the edge of the conveyor belt. The size of the slots and latches has been carefully designed, and the plug-in and pull-out operation is convenient and the connection is firm, which can meet the stability requirements of the conveyor belt during operation. When disassembly is required, it can be easily separated by manual operation. In this way, after the conveyor belt reaches the end of its service life, the various components can be easily disassembled, and the recycled polytetrafluoroethylene material can enter the recycling process again. Other components can also be classified and processed to improve the recycling rate of resources.

[0034] In another embodiment, a specific implementation method of a polytetrafluoroethylene recycling and production conveyor belt process in a material transportation scenario in an electronic component production workshop is provided, including: Implementation background: In the production workshop of electronic components, the material conveying system has strict requirements for conveyor belts. The conveyor belt needs to have excellent anti-static performance to prevent damage to components caused by static electricity during the conveying of electronic components; it should have good high-temperature resistance to meet the material conveying requirements near some high-temperature process links in the workshop; at the same time, it should meet the cleanliness requirements to avoid generating pollutants such as dust and debris during the conveying process, which may affect the quality of electronic components. Considering environmental protection and sustainable development, it is hoped to use recycled materials to make conveyor belts that meet the above conditions.

[0035] Pretreatment of recycled materials: Impurity removal: Magnetic separation step: The sorted recycled polytetrafluoroethylene materials are conveyed to the magnetic separation equipment. The magnetic field intensity of the magnetic separation equipment is set to 0.3T. Through this magnetic field intensity, small metal particles mixed into the materials are effectively adsorbed and removed. These metal particles may have been accidentally mixed in during the previous installation and use, such as small screws for fixation, metal debris, etc., to ensure that no quality problems occur due to these impurities in the subsequent processing.

[0036] Electrostatic separation step: Then, the materials after magnetic separation are sent into the electrostatic separation device. The electric field intensity is adjusted to 3 kV / cm. With the action of the electrostatic field, non-polytetrafluoroethylene foreign matters such as plastic fibers and paper debris that are attached to the surface of the polytetrafluoroethylene materials due to electrostatic adsorption are separated, improving the purity of the materials and laying a good foundation for the subsequent process steps.

[0037] Microwave-assisted cleaning and activation: Preparation of cleaning medium: Weigh alkyl polyglycoside surfactant and water in a mass ratio of 1:60. First, pour the water into a stainless-steel container, and then slowly add the alkyl polyglycoside surfactant. At the same time, stir with a stainless-steel stirring rod at a speed of about 80 revolutions per minute for 6 minutes to make a uniform and transparent mixed cleaning medium.

[0038] Microwave cleaning and activation: Put the recycled polytetrafluoroethylene materials after impurity removal into the microwave treatment equipment, add an appropriate amount of the above cleaning medium, and then turn on the equipment. Utilize the thermal effect generated by microwave radiation to quickly raise the temperature of the cleaning medium, efficiently dissolve and remove impurities such as oil stains, dust, and possibly residual chemical substances on the material surface. At the same time, the non-thermal effect of microwaves promotes the generation of more active sites on the surface of the polytetrafluoroethylene materials, which is beneficial to the bonding of the subsequent modified materials and the matrix. After cleaning, the cleaning medium and the materials are separated by centrifugation. Subsequently, the materials are placed in a low-temperature vacuum drying oven and dried at a temperature of 35°C for 2.5 hours to ensure that the materials are dry and their performance is not damaged.

[0039] Modification treatment of recycled materials: Antistatic agent modification: Addition of antistatic agent: Select a polyether ester amide antistatic agent with persistent antistatic performance and add it to the pretreated material at a ratio of 4% of the total mass of recycled polytetrafluoroethylene. This type of antistatic agent can form conductive channels in the polytetrafluoroethylene matrix, effectively dissipate static electricity, and prevent the harm caused by static electricity accumulation to electronic components.

[0040] Mixing operation: Put the two into a high-speed mixer, set the rotation speed to 800 revolutions per minute, and the mixing time to 15 minutes. Through sufficient stirring, the antistatic agent is evenly dispersed in the polytetrafluoroethylene matrix, ensuring that the entire conveyor belt has stable and good antistatic performance and meets the static protection requirements of the electronic component production workshop.

[0041] High-temperature resistant inorganic filler modification: Selection and addition of inorganic filler: Select nano-scale alumina ceramic powder as the high-temperature resistant inorganic filler, which has excellent high-temperature resistance, chemical stability, and mechanical strength. Add nano-alumina ceramic powder to the material at a ratio of 8% of the total mass of recycled polytetrafluoroethylene. This addition amount has been verified by experiments, which can not only effectively improve the high-temperature resistance of the conveyor belt but also will not have too much impact on the processing performance of the material.

[0042] Dispersion and bonding treatment: First, disperse the nano-alumina ceramic powder in polytetrafluoroethylene by ultrasonic dispersion for 25 minutes, then add an appropriate amount of coupling agent to further enhance the bonding force between the filler and the polytetrafluoroethylene matrix, and then ball mill for 20 minutes to ensure that the filler is evenly dispersed and tightly bonded to the matrix. Through this modification, when the conveyor belt passes near the high-temperature process section in the electronics workshop, it can maintain a stable structure and will not deform or have a decline in performance due to high temperature.

[0043] Antibacterial and mildew-proof agent modification: Addition of antibacterial and mildew-proof agent: To meet the strict requirements for cleanliness in the electronic component production workshop, add nano-silver ion antibacterial and mildew-proof agent and add it to the material at a ratio of 1% of the total mass of recycled polytetrafluoroethylene. Nano-silver ions have high antibacterial and mildew-proof effects, can inhibit the growth of microorganisms on the surface of the conveyor belt, and reduce pollutants such as dust and debris generated by microbial activities, ensuring the cleanliness of the environment where electronic components are located during the conveying process.

[0044] Uniform mixing: Put the material containing nano-silver ion antibacterial and mildew-proof agent into the high-speed mixer again and stir at a speed of 600 revolutions per minute for 10 minutes to make it evenly dispersed in the polytetrafluoroethylene matrix, ensuring that the entire conveyor belt surface has antibacterial and mildew-proof functions and preventing the quality of electronic components from being affected by microbial growth.

[0045] Specific forming process: Considering that the shape of the conveyor belt is relatively regular and the dimensional accuracy requirements are relatively high, and at the same time, the water-assisted injection molding process helps to ensure the surface quality and dimensional accuracy of the product, it is decided to use the water-assisted injection molding process to manufacture the conveyor belt.

[0046] Water-assisted injection molding operation: Add the recycled polytetrafluoroethylene mixed material after modification treatment to the barrel of the injection molding machine. According to the melting characteristics of the material, gradually heat it to about 310 °C through the heating device outside the barrel, so that the material gradually changes from a solid state to a melt state with good fluidity. Then, inject the melt into the mold cavity with the shape of the conveyor belt designed in advance. After the melt is filled to a certain extent, start the water-assisted injection molding system specially configured on the injection molding machine, inject high-pressure water into the mold cavity, and use the pressure of the water to push the melt to continue to fill every fine part of the mold, ensuring the integrity and dimensional accuracy of the product. After injection molding, the discharged water can be recycled after filtration, purification and other treatments. At the same time, the water-assisted injection molding makes the conveyor belt product obtain a smooth surface, reduces surface defects, and better meets the cleanliness requirements of the electronic component production workshop.

[0047] Post-molding treatment: After the conveyor belt is demolded, perform fine grinding and polishing on its surface to remove possible small burrs, further improve the surface finish, make it meet the high-standard cleanliness requirements of the electronic component production workshop, and at the same time ensure that the electronic components will not be damaged due to uneven surface during transportation.

[0048] Post-treatment and sustainable design: Antistatic coating protection: Coating preparation: Mix the antistatic polyurethane resin and conductive carbon nanotubes in a mass ratio of 10:1, add an appropriate amount of diluent (accounting for 5% of the total mass) and leveling agent (accounting for 0.2% of the total mass), and fully stir evenly to make the antistatic coating material.

[0049] Coating application: Apply the antistatic coating evenly to the molded conveyor belt by spraying, control the coating thickness at about 20 μm, further enhance the antistatic performance of the conveyor belt, ensure that static electricity can be dissipated more effectively during the transportation of electronic components, and ensure the safety of electronic components.

[0050] Recyclable and easy-to-disassemble design: In the structural design of the conveyor belt, a pluggable fixed structure is adopted. Uniformly spaced slots and pins are set at the edge of the conveyor belt, with a group every 20 cm. Its structural design ensures firm connection and easy disassembly. In this way, after the conveyor belt reaches the end of its service life, each component can be easily disassembled, the recycled polytetrafluoroethylene material can enter the recycling process again, and other components can also be classified for treatment, improving the recycling rate of resources and conforming to the concept of environmental protection and sustainable development.

[0051] In summary, the process of recycling and manufacturing conveyor belts from polytetrafluoroethylene according to the present invention uses specific modified materials and reasonable process steps to produce high-performance and environmentally sustainable conveyor belt products that meet the requirements of different scenarios, and has high practical value and promotion prospects.

[0052] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0053] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A process for recycling and manufacturing a conveyor belt from polytetrafluoroethylene, characterized in that, It includes the following steps: Pre-treat the recycled polytetrafluoroethylene material to remove impurities and activate the material surface; Modify the pre-treated material by adding modifiers to improve the material properties; Use a specific molding process to process the modified material into the shape of a conveyor belt; Post-treat and conduct sustainable design on the formed conveyor belt to make it easy to recycle and disassemble and have protective performance.

2. The process for recycling and manufacturing a conveyor belt from polytetrafluoroethylene according to claim 1, characterized in that, The pre-treatment of the recycled polytetrafluoroethylene material specifically includes: Classified collection: Classify and collect the collected recycled polytetrafluoroethylene materials according to the source, usage status and material characteristics; Impurity removal: Use the combined method of magnetic separation and electrostatic separation to remove metal impurities and other foreign objects that are not polytetrafluoroethylene. The magnetic field intensity of the magnetic separation equipment is between 0.1 - 1T, and the electric field intensity of the electrostatic separation device is between 1 - 10 kV / cm; Microwave-assisted cleaning and activation: Use microwave-assisted cleaning technology. Place the material in a microwave treatment equipment, add a mixed cleaning medium of water and biodegradable surfactant, and use the thermal effect and non-thermal effect of microwave to remove oil stains, chemical residues and activate the material surface, and finally conduct drying treatment.

3. A process for recycling and manufacturing a conveyor belt from polytetrafluoroethylene according to claim 1, characterized in that, The modification treatment specifically includes: Bio-based additive modification: Add lignin nanoparticles to the pre-treated material according to the proportion of 3% - 8% of the total mass of the recycled polytetrafluoroethylene. The particle size range of the lignin nanoparticles is 50 - 500 nm; Fully mix evenly through a high-speed mixer, and use lignin nanoparticles to enhance the mechanical properties of the conveyor belt and endow it with anti-ultraviolet ability; Degradable polymer blending modification: Select polylactic acid and add it to the twin-screw extruder together with recycled polytetrafluoroethylene according to the proportion of 10% - 20% of the total mass of the blend, and conduct blending in the temperature range of 180 - 250 °C to make the polylactic acid evenly dispersed in the polytetrafluoroethylene matrix, so as to improve the processing performance of the conveyor belt; Photocatalytic self-cleaning modification: Prepare a composite powder of nano-titanium dioxide and graphene, and add it to the material according to the proportion of 2% - 6% of the total mass of the recycled polytetrafluoroethylene; Ensure its uniform dispersion through ultrasonic dispersion and ball milling processes, and use the photocatalytic effect of nano-titanium dioxide under light to decompose the pollutants on the surface of the conveyor belt to achieve the self-cleaning function.

4. The process for recycling and manufacturing a conveyor belt from polytetrafluoroethylene according to claim 1, characterized in that, The specific molding process includes water-assisted injection molding and hot pressing molding. Specifically: Water-assisted injection molding: If the shape and structure of the conveyor belt are applicable, add the modified material to the barrel of the injection molding machine and heat it to 280 - 330 °C to make it melt; After injecting into the mold cavity, inject high-pressure water of 10 - 30 MPa to push the melt to fill the mold, and the water is recycled after treatment; Hot pressing molding and waste heat recovery and utilization: If the hot pressing molding process is adopted, place the modified material in a hot pressing mold and conduct hot pressing molding under the conditions of a hot pressing temperature of 300 - 360 °C, a pressure of 15 - 25 MPa and a holding pressure time of 30 - 90 minutes; After molding, use a heat exchanger to collect waste heat. The heat exchanger is made of copper alloy material and is internally provided with a spiral circulating water channel to improve the heat transfer efficiency. The recovered hot water is used to preheat the next batch of materials or for workshop heating.

5. A process for recycling polytetrafluoroethylene to produce a conveyor belt according to claim 1, characterized in that, The post-treatment and sustainable design specifically include: Coating protection with plant extracts: Mix rosemary extract with antibacterial and antioxidant functions and an aqueous film-forming agent in a certain proportion, and add appropriate additives to make an aqueous protective coating; Apply the coating to the conveyor belt by spraying or dipping, and control the coating thickness between 10 - 50 μm to inhibit microbial growth and delay aging; Recyclable and easily disassembled design: When designing the conveyor belt structure, use snap connections or pluggable fixed structures to avoid using connection means that are difficult to separate, facilitating the disassembly and classification recycling of each component after the conveyor belt is scrapped.

6. A process for recycling polytetrafluoroethylene to produce a conveyor belt according to claim 2, characterized in that, In the combined method of magnetic separation and electrostatic separation, the magnetic field intensity of the magnetic separation equipment is 0.5 T, and the electric field intensity of the electrostatic separation device is 5 kV / cm to ensure the impurity removal effect.

7. A process for recycling and manufacturing a conveyor belt from polytetrafluoroethylene according to claim 3, characterized in that, The particle size of the lignin nanoparticles is 200 nm, and the nanometer processing technology is a combination of ball milling and ultrasonic dispersion to ensure good dispersion and reinforcement effect in the polytetrafluoroethylene matrix.

8. A process for recycling and manufacturing a conveyor belt from polytetrafluoroethylene according to claim 4, characterized in that, The diameter of the spiral circulating water channel of the heat exchanger is 5 mm, and the pitch is 10 mm to further improve the heat transfer efficiency.