Waste polyvinyl chloride cable sheath recycling method

Abstract

The invention discloses a waste polyvinyl chloride cable sheath recycling method which comprises the following steps: crushing, cleaning and drying a waste polyvinyl chloride cable sheath to obtain a PVC crushed material; the PVC crushed material is subjected to homogenization treatment, and a homogenized PVC crushed material is obtained; the homogenized PVC crushed material is subjected to granulation, and a PVC regenerated material is obtained; and carrying out modification treatment on the PVC regenerated material to obtain the PVC cushion material. According to the invention, efficient cleaning recovery and high-performance regeneration of the waste PVC cable sheath can be realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polymer material utilization, and particularly relates to a recycling method of waste polyvinyl chloride (PVC) cable sheath. BACKGROUND

[0002] At present, the large accumulation and improper treatment of waste PVC cable sheath have become a prominent problem restricting resource recycling and environmental sustainable development. Traditional recycling methods mostly adopt mechanical crushing and hot melting reconstruction, and have problems such as low recycling efficiency, serious decline of material performance, poor interface adhesion, etc., which are difficult to meet the actual application requirements of high-performance regenerated materials; at the same time, the residual plasticizer, filler and other additives in PVC are not easy to completely remove, which affects the subsequent modification and processing. In addition, due to the poor thermal stability and narrow processing window of PVC, traditional high-temperature modification treatment easily leads to decomposition and release of harmful gases, increasing the environmental burden and processing cost.

[0003] Therefore, it is urgent to develop a new recycling method of PVC cable sheath, which can not only realize the deep activation and reconstruction of material performance, but also ensure the clean and functional modification process, so as to promote the high-value regeneration of waste PVC materials. SUMMARY

[0004] In view of the deficiencies in the prior art, the purpose of the present application is to provide a recycling method of waste polyvinyl chloride cable sheath, which aims to improve the clean recycling and high-performance regeneration of waste PVC cable sheath.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions: A recycling method of waste polyvinyl chloride cable sheath, the method comprising: crushing, cleaning and drying the waste polyvinyl chloride cable sheath to obtain PVC crushed material; homogenizing the PVC crushed material to obtain homogenized PVC crushed material; granulating the homogenized PVC crushed material to obtain PVC regenerated material; modifying the PVC regenerated material to obtain PVC cushion material.

[0006] Optionally, the crushing, cleaning and drying of the waste polyvinyl chloride cable sheath to obtain the PVC crushed material comprises: crushing the waste polyvinyl chloride cable sheath by laser; cleaning the crushed waste polyvinyl chloride cable sheath based on supercritical carbon dioxide; and drying the cleaned waste polyvinyl chloride cable sheath by electromagnetic wave resonance.

[0007] Optionally, the PVC shredded material is homogenized to obtain homogenized PVC shredded material, including: swelling and activating the homogenized PVC shredded material; stimulating the swollen and activated PVC shredded material; performing near-infrared laser scanning on the stimulated PVC shredded material to trigger a dynamic phase; and depressurizing and cyclone separating the PVC shredded material after triggering the dynamic phase.

[0008] Optionally, the exciting process of the swollen and activated PVC fragments includes: exciting the PVC fragments by applying a dual-frequency ultrasonic field to the swollen and activated PVC fragments.

[0009] Optionally, the step of depressurizing the PVC crushed material after triggering the dynamic phase includes: performing gradient depressurization on the PVC crushed material after triggering the dynamic phase.

[0010] Optionally, the homogenized PVC shreds are granulated to obtain recycled PVC material, including: plasticizing the homogenized PVC shreds to obtain plasticized PVC shreds; plasma treating the plasticized PVC shreds to obtain plasma-treated PVC shreds; and pulse shearing the plasma-treated PVC shreds to obtain recycled PVC material.

[0011] Optionally, the plasticizing treatment of homogenized PVC scrap to obtain plasticized PVC scrap includes: mixing modified nanocellulose aerogel fragments loaded with environmentally friendly plasticizers with homogenized PVC scrap to obtain a mixture; and subjecting the mixture to microwave irradiation to obtain plasticized PVC scrap.

[0012] Optionally, the PVC recycled material is modified to obtain PVC underlay material, including: performing multi-stage pore activation pretreatment on the PVC recycled material; and performing a grafting modification reaction on the activated pretreated PVC recycled material to obtain PVC underlay material.

[0013] Optionally, the multi-stage pore activation pretreatment of the PVC recycled material includes: immersing the PVC recycled material in a composite fluid formed by mixing supercritical CO2 and ionic liquids [EMIM][DEP], and treating it under supercritical conditions; and depressurizing the PVC recycled material treated under supercritical conditions.

[0014] Optionally, the grafting modification reaction of the activated pretreated PVC recycled material to obtain PVC padding material includes: placing the activated pretreated PVC recycled material in an inert atmosphere for heating; introducing modified monomers into the heated PVC recycled material and simultaneously adding free radical initiators to initiate the grafting reaction; and obtaining PVC padding material after the reaction is completed.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: This application, through deep recycling and functional reconstruction of waste PVC cable sheaths, can not only improve the chain segment activity and structural uniformity of PVC, but also improve its interfacial adhesion, thermal stability and anti-aging properties. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of a method for recycling and reusing waste polyvinyl chloride cable sheaths according to an embodiment of this application. Detailed Implementation

[0017] Specific embodiments of this application will now be described in detail with reference to the accompanying drawings. While specific embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0018] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0019] To facilitate understanding of the embodiments of this application, the following will provide further explanation and description with reference to the accompanying drawings and specific embodiments, and the accompanying drawings do not constitute a limitation on the embodiments of this application.

[0020] Figure 1 This is a schematic flowchart illustrating a method for recycling and reusing waste polyvinyl chloride cable sheaths according to an embodiment of this application. Figure 1 As shown, the method includes the following steps: S100: Crushing, cleaning, and drying waste PVC cable sheaths to obtain PVC crushed material; S200: The PVC shredded material is homogenized to obtain homogenized PVC shredded material; S300: The homogenized PVC crushed material is granulated to obtain recycled PVC material; S400: Modify the PVC recycled material to obtain PVC underlay material.

[0021] This embodiment constructs a systematic and efficient recycling process chain for waste PVC cable sheaths through four steps, S100 to S400, realizing the transformation from raw waste to high-performance PVC underlayment material. Specifically, step S100 achieves purification and particle size control of the raw cable sheath, ensuring consistency and basic quality in subsequent processing; step S200 uses supercritical fluids, dynamic crosslinking, and physical activation to deeply homogenize the crushed material, significantly improving molecular chain segment activity and structural homogeneity; step S300 employs precise plasticization and plasma modification to construct recycled particles with stable structure and excellent processability; step S400 further endows the material with excellent interfacial bonding and environmental stability through pore activation and directional grafting. Overall, this method, while ensuring environmental friendliness, can improve the physical properties, thermal stability, and application adaptability of recycled PVC, thereby achieving high-value and functional recycling of waste PVC materials.

[0022] In another exemplary embodiment, step S100, which involves crushing, cleaning, and drying the waste PVC cable sheath to obtain PVC crushed material, includes the following steps: S101: Using laser to crush waste PVC cable sheaths; In this step, this embodiment uses a high-power laser beam to irradiate the waste PVC cable sheath, so that the laser energy is focused on the surface of the cable sheath or a specific area, thereby heating the PVC material to near its melting point, causing it to soften and become brittle locally, without requiring excessive physical impact. This reduces the energy required for mechanical crushing and achieves precise crushing.

[0023] This embodiment uses laser to crush waste PVC cable sheaths. Firstly, it avoids the mechanical stress damage caused by mechanical pressure in traditional crushing processes, thus preserving the original properties of the waste PVC cable sheaths. Secondly, during laser crushing, due to precise energy control, the fragments of the waste PVC cable sheaths can be effectively controlled within a certain range, greatly reducing fragment scattering and loss (the laser can directly destroy the molecular structure of PVC, making the material pyrolysis process more uniform, thus ensuring the integrity of the material and recycling efficiency). Thirdly, by adjusting the laser power, focus position, and irradiation time, the particle size of the crushed waste PVC cable sheaths can be precisely controlled. It should be noted that in this embodiment, the diameter of the crushed material obtained after crushing the waste PVC cable sheaths needs to be controlled to be less than 1 cm. This is because: firstly, crushed material with a diameter of less than 1 cm is easier to thoroughly clean during subsequent cleaning processes. Larger particle sizes can lead to uneven cleaning, especially when using chemical solvents or ultrasonic cleaning. Larger particles have a smaller surface area, making it difficult for them to fully contact the cleaning medium, thus affecting the cleaning effect. Secondly, crushed materials with a diameter of less than 1 cm can increase the rate of moisture evaporation, ensuring uniformity and efficiency in the drying process. However, larger crushed materials are heated unevenly during the drying process, leading to localized overheating or incomplete drying.

[0024] S102: Cleaning of crushed waste PVC cable sheaths using supercritical carbon dioxide; In this step, this embodiment utilizes supercritical carbon dioxide (scCO2) as the cleaning medium to clean the crushed waste PVC cable sheath. Supercritical carbon dioxide possesses dual properties of both liquid and gas near its critical point, allowing it to penetrate the tiny pores of the PVC cable sheath, thereby dissolving and removing oil, plastic additives, and other impurities. By using supercritical carbon dioxide to clean the crushed waste PVC cable sheath, surface impurities can be effectively removed without damaging the material, thus avoiding the harmful solvents and high energy consumption that may be used in traditional cleaning methods.

[0025] S103: Drying the cleaned waste PVC cable sheath through electromagnetic wave resonance.

[0026] In this step, this embodiment uses electromagnetic waves with a specific frequency (e.g., microwaves with a frequency of 2.45 GHz (which has been verified to be one of the frequencies with the strongest absorption capacity of water molecules) or radio frequency waves with a frequency of 30 MHz to 300 MHz) to excite the water molecules in the polyvinyl chloride cable sheath, causing them to resonate and thus quickly release the moisture.

[0027] Compared to traditional drying methods, electromagnetic wave resonance can efficiently heat the internal molecules of the cleaned waste PVC cable sheath to quickly evaporate the moisture, thereby greatly reducing heat loss and time consumption.

[0028] In another exemplary embodiment, step S200 involves homogenizing the PVC shredded material to obtain homogenized PVC shredded material, including the following steps: S201: Swelling and activation of homogenized PVC crushed material; In this step, the homogenized PVC fragments are placed in a supercritical CO2 reactor (temperature 35℃ to 40℃, pressure 8MPa to 10MPa), while scCO2 fluid containing 0.5wt% to 2wt% dynamic crosslinking agent (such as an organosilicon compound containing disulfide bonds) is introduced to swell and activate the homogenized PVC fragments. During this process, scCO2, with its supercritical characteristics of both gas and liquid phases, has extremely strong permeability and dissolving ability, and can quickly enter the microstructure of the homogenized PVC fragments, significantly improving the fluidity of polymer chain segments and the intermolecular distance, so that the homogenized PVC fragments are in a highly swollen and activated state. At the same time, the dynamic crosslinking agent can be uniformly distributed in the PVC system with the transport capacity of the scCO2 medium, and through its reversible disulfide bond structure, it can weakly interact with or controllably crosslink with the PVC molecular chains, further relaxing the binding structure between chains and inducing the directional rearrangement and stress release of the internal chain segments of the homogenized PVC fragments.

[0029] This swelling and activation process not only helps to improve the plasticity and reactivity of homogenized PVC crushed material, but also provides an ideal molecular preparation state for subsequent ultrasonic excitation, plasma modification and dynamic reconstruction, thereby enhancing the homogeneity, functionalization efficiency and material performance basis of recycling processing.

[0030] S202: Activation of swollen and activated PVC crushed material; In this step, this embodiment excites the PVC fragments by applying a dual-frequency ultrasonic field (20kHz low frequency and 40kHz high frequency) to the swollen and activated PVC fragments. The low-frequency ultrasound induces a strong cavitation effect, generating rapid expansion and collapse of microbubbles, thereby locally releasing high energy to break the micro-crystal structure of the PVC fragments, disrupting the highly ordered arrangement between polymer chain segments, and increasing the randomness and chain segment freedom of the PVC fragments. Simultaneously, the high-frequency ultrasound excites the movement of molecular chain segments through continuous and precise mechanical vibration, promoting the release and reconstruction of inter-chain stress, providing a favorable conformational basis for subsequent dynamic bonding.

[0031] Based on this, an atmospheric pressure cold plasma jet (using argon as the working medium and power controlled between 50W and 100W) is further activated to bombard the surface of PVC crushed material with high-energy ions, which can achieve micro-etching and functionalization modification of the surface without causing thermal damage.

[0032] The above excitation process, on the one hand, can construct rich microstructures on the surface of PVC shredded material at the microscale, increasing the specific surface area and helping to enhance the interfacial bonding ability in subsequent processing; on the other hand, by introducing active groups, it is beneficial to improve subsequent cross-linking reactions and interfacial compatibility. In this embodiment, the synergistic excitation of dual-frequency ultrasound and plasma can improve the structural relaxation, surface activity, and reaction sensitivity of PVC shredded material, laying a key physical and chemical foundation for the construction of high-performance recycled materials.

[0033] S203: Near-infrared laser scanning is performed on the excited PVC crushed material to trigger the dynamic phase; In this step, after completing dual-frequency ultrasound and plasma excitation, this embodiment performs near-infrared laser scanning on the PVC shredded material. Specifically, a near-infrared laser with a wavelength in the range of 800nm ​​to 1100nm is selected, with a low energy density (e.g., 0.5W / cm²). 2 ~2 W / cm 2 The laser beam is directed to irradiate the surface and interior of PVC granules. This laser wavelength can be efficiently absorbed by specific functional groups or crosslinking agents in the PVC granules, thereby locally heating and activating the previously introduced dynamic crosslinking system (such as disulfide bond structures). This causes the crosslinking bonds to undergo reversible breakage and reconstruction under heated or stimulated conditions, forming a transient "dynamic phase" state. This dynamic phase exhibits controllable unentanglement and rapid recombination capabilities between polymer chain segments, thus giving the PVC granules stress responsiveness and deformation adaptability, which is beneficial for improving its structural adaptability and interfacial bonding efficiency in subsequent processing.

[0034] S204: Depressurize and separate PVC crushed material after triggering the dynamic phase.

[0035] In this step, after near-infrared laser triggering and dynamic phase formation, this embodiment performs gradient depressurization on the PVC shredded material. This involves gradually reducing the system pressure under controlled conditions, allowing the PVC shredded material to smoothly transition from a high-pressure supercritical state to atmospheric pressure. (For example, in the first stage, the pressure is reduced from 9.5 MPa to 6 MPa at a rate of 0.3 MPa / min, allowing scCO2 to gradually leave the supercritical state and releasing internal pressure to prevent structural damage caused by excessive internal and external pressure differences; in the second stage, a constant pressure of 6 MPa is maintained for 1 minute, allowing a temporary equilibrium between the PVC shredded material and CO2, causing residual CO2 to slowly precipitate from the PVC shredded material and reducing pressure within the micropores; in the third stage, the pressure is rapidly reduced from 6 MPa to atmospheric pressure at a rate of 1 MPa / min, allowing rapid system depressurization after the PVC shredded material has completed structural stabilization, preventing CO2 retention.) This prevents the collapse of the internal structure or uncontrolled cross-linking of the shredded material due to a sudden pressure drop. During this process, polymer chain segments undergo a dynamic phase-to-stable configuration transformation under depressurization induction, locking in the previously formed chain entanglement network and microstructure.

[0036] Subsequently, the PVC crushed material after gradient depressurization is introduced into a cyclone separator. The centrifugal force generated by the high-speed rotating airflow is used to achieve efficient separation of particles and impurities. In particular, it can remove residual impurities with particle size in the micron range, such as metal shavings and coking fragments, so as to achieve fine control of the purity of PVC crushed material.

[0037] In summary, this step, through the synergistic effect of gradient depressurization and cyclone separation, can not only effectively solidify the highly active molecular structure established in the previous stage, maintaining particle uniformity and structural integrity, but also improve the purity and processability of subsequent PVC recycled materials, thereby providing a high-quality precursor base for subsequent granulation and functional modification.

[0038] In another exemplary embodiment, step S300 involves granulating the homogenized PVC crushed material to obtain recycled PVC material, including the following steps: S301: Plasticizing homogenized PVC scrap material to obtain plasticized PVC scrap material; In this step, modified nanocellulose aerogel fragments (2mm particle size) loaded with an environmentally friendly plasticizer (acetylthiol tributyl citrate) are mixed with homogenized PVC crushed material at a volume ratio of 1:10 to obtain a mixture, which allows the aerogel fragments to be embedded in the pores of the homogenized PVC crushed material to form a "micro-pump-storage" structure; then, it is irradiated with 2450MHz microwave (2W / cm²). 2 (×90s) Triggers the mixture particles to heat up to 60℃, driving the plasticizer to be released directionally into the PVC crushed material, forming a concentration gradient of 40wt% on the surface and 15wt% in the core, achieving precise plasticization at low temperature.

[0039] S302: Plasma treatment is applied to plasticized PVC shredded material to obtain plasma-treated PVC shredded material; In this step, the plasticized PVC shredded material is placed in a dual dielectric barrier discharge (DBD) plasma environment (gas composition: helium / oxygen = 95:5, treatment intensity: 3 W / cm²). 2 The process involves selectively etching the particle surface with high-energy plasma (lasting 30 seconds) to form a micro-pit array structure with a depth of 2 to 5 micrometers, thereby significantly increasing the specific surface area of ​​the particles and the subsequent interfacial bonding area. At the same time, the plasma effect can introduce a large number of polar oxygen-containing groups (such as carbonyl-C=O) on the surface, increasing its density and enhancing the surface chemical reactivity. In addition, this process has excellent selectivity, which can remove the relatively loose amorphous regions while retaining the crystalline phase, ultimately constructing a "hard core-soft shell" type composite reinforcement structure on the particle surface, which helps to improve the mechanical properties, stability and interfacial compatibility of subsequent recycled PVC particles. S303: Pulse shearing is performed on plasma-treated PVC shreds to obtain recycled PVC.

[0040] In this step, under low temperature conditions of 80℃ to 90℃, a special waveform screw is used to apply 150rpm pulsed shear (stress of 0.5MPa to 1MPa), triggering the mechanochemical exchange reaction of disulfide bonds in the dynamic crosslinking agent (R1-SS-R2→2R•→R1-SS-R1), so that the molecular chains of the plasma-treated PVC crushed material are reconstructed into an entangled network along the stress direction; when extruding through a PTFE / graphene mold, 40kHz ultrasonic vibration is used to eliminate melt fracture, and a 100V pulse voltage is applied to induce a sudden drop in surface energy, thereby achieving the self-peeling molding of ellipsoidal particles (Φ3mm).

[0041] In another exemplary embodiment, step S400 involves modifying the recycled PVC material to obtain PVC underlay material, including the following steps: S401: Multi-stage pore activation pretreatment of recycled PVC materials; In this step, recycled PVC material is immersed in a solution of supercritical CO2 and an ionic liquid [EMIM]. + [DEP] - ([EMIM]) +A composite fluid (mass ratio 9:1) was formed by mixing 1-ethyl-3-methylimidazolium cation and [DEP]⁻: diethyl phosphate anion. The mixture was then treated for 20 minutes under supercritical conditions (temperature 35℃ to 40℃, pressure 7 MPa to 9 MPa). Utilizing the strong permeability of the ionic liquid and the swelling effect of scCO2, the multi-level pores (micropores → mesopores) inside the recycled PVC were synergistically opened, forming an activation layer with a depth of up to 200 μm. After treatment, rapid depressurization caused spontaneous phase separation of the composite fluid and the escape of supercritical CO2, while the ionic liquid selectively remained in the pores, serving as a carrier and diffusion medium for subsequent grafting modification reactions.

[0042] S402: Graft modification reaction is carried out on the activated pretreated PVC recycled material to obtain PVC underlay material. After the reaction is completed, PVC underlay material is obtained.

[0043] In this step, the activated pretreated recycled PVC material is first placed in an inert atmosphere (such as nitrogen) and heated to 60°C to 80°C to maintain stable reaction conditions. Then, a modified monomer (such as methyl methacrylate (MMA), maleic anhydride (MAH), chitosan, or a silane coupling agent) is introduced, along with a free radical initiator (such as dicumyl peroxide or benzoyl peroxide), to initiate the grafting reaction under a free radical reaction mechanism. At this point, the ionic liquid retained in the pores of the recycled PVC acts as a microreaction medium, effectively promoting the diffusion and penetration of the modified monomer within the recycled PVC material. This improves the uniformity and efficiency of the grafting reaction, achieving a directional and controllable molecular grafting reaction.

[0044] In addition, after the above reaction is completed, the modified PVC material is thoroughly washed to remove unreacted monomers and residual ionic liquids. After drying, the modified PVC material with optimized performance, namely PVC underlay material, can be obtained.

[0045] Below, this application tests the PVC underlay material prepared based on the above embodiments and compares it with recycled PVC prepared based on conventional methods. The specific testing process is as follows: 1. Modified PVC padding material processed by the process described in this application was selected and pressed into sample pieces with a thickness of 2 mm using a standard mold. The sample pieces were 100 mm × 100 mm in size. In addition, all sample pieces were pretreated in a constant temperature and humidity chamber (23°C, 50%RH, 48 hours) to eliminate environmental influences.

[0046] 2. The pretreated sample pieces were subjected to tests including mechanical properties (including tensile strength and elongation at break (tested at a rate of 50 mm / min on an electronic universal testing machine (Instron 3365), hardness (measured using a Shore A hardness tester) and tear strength (using a V-tear test strip)), thermal properties (including Vicat softening point (tested using a Vicat deformation temperature meter) and thermal stability (using a thermogravimetric analyzer, heating to 600℃ at 10℃ / min in a nitrogen atmosphere)), interfacial adhesion properties (hot-pressing the sample piece to the rubber substrate, and then performing a peel test after cooling to determine the interfacial bond strength), and water absorption and aging resistance properties (including water absorption (weighing the sample piece after immersing it in de-emulsified water for 24 hours) and artificial accelerated aging (testing the change in tensile properties after cyclic irradiation and condensation in a UV aging chamber (e.g., irradiation for 8 hours followed by condensation for 4 hours))).

[0047] After the above tests, the test results are shown in Table 1: Table 1

[0048] The test results shown in Table 1 indicate that the PVC underlayment material obtained by the method described in this application is superior to traditional recycled PVC in terms of mechanical properties, thermal stability, interfacial adhesion, and environmental resistance. In particular, it shows significant performance in terms of elongation at break (+46.7%), tear strength (+47.8%), and interfacial bond strength (+68.6%), which verifies that the PVC underlayment material obtained by the method described in this application has better performance than traditional PVC.

[0049] Furthermore, the PVC underlayment material obtained based on the method described in this application possesses excellent mechanical properties, interfacial adhesion, thermal stability, and aging resistance. Compared to traditional PVC materials, it is more suitable for applications with higher performance requirements, such as floor underlayment, cable sheathing, building waterproofing layers, traffic cushioning materials, and adhesive substrates in multi-layer composite structures. Its higher tensile strength and elongation at break enhance load-bearing and impact resistance, while stronger interfacial adhesion enables a firm bond with dissimilar materials such as rubber and metal. Superior thermal stability and UV aging resistance ensure long-term stability in complex environments such as outdoor, high-temperature, and humid conditions, thereby significantly extending product lifespan and reducing maintenance frequency, resulting in higher engineering adaptability and environmental tolerance.

[0050] The above embodiments are only for illustrating the technical concept and features of this application, and are intended to enable those skilled in the art to understand the content of this application and implement it accordingly. They should not be construed as limiting the scope of protection of this application. All equivalent changes or modifications made in accordance with the spirit and essence of this application should be included within the scope of protection of this application.

Claims

1. A method for recycling and reusing waste polyvinyl chloride cable sheaths, characterized in that, The method includes: Waste polyvinyl chloride (PVC) cable sheaths are crushed, cleaned, and dried to obtain PVC crushed material; The PVC shredded material is homogenized to obtain homogenized PVC shredded material; The homogenized PVC crushed material is granulated to obtain recycled PVC material; The recycled PVC material is modified to obtain PVC underlayment material.

2. The method according to claim 1, characterized in that, The process of crushing, cleaning, and drying waste PVC cable sheaths to obtain PVC crushed material includes: Laser is used to crush waste polyvinyl chloride cable sheaths; Cleaning of crushed waste PVC cable sheaths using supercritical carbon dioxide; The waste PVC cable sheath is dried by electromagnetic wave resonance after cleaning.

3. The method according to claim 1, characterized in that, The PVC shredded material is homogenized to obtain homogenized PVC shredded material, comprising: Swelling and activation of homogenized PVC crushed material; Activation of swollen and activated PVC fragments; Near-infrared laser scanning was performed on the excited PVC crushed material to trigger the dynamic phase; The PVC crushed material after the dynamic phase is triggered is subjected to depressurization and cyclone separation.

4. The method according to claim 3, characterized in that, The activation of the swollen and activated PVC fragments includes: The PVC shredded material was excited by applying a dual-frequency ultrasonic field to it after it had swollen and activated.

5. The method according to claim 3, characterized in that, The process of reducing the pressure on the PVC crushed material after triggering the dynamic phase includes: performing gradient pressure reduction on the PVC crushed material after triggering the dynamic phase.

6. The method according to claim 1, characterized in that, The homogenized PVC crushed material is granulated to obtain recycled PVC material, comprising: Plasticizing homogenized PVC scrap material is subjected to plasticizing treatment to obtain plasticized PVC scrap material. Plasma treatment was performed on plasticized PVC shredded material to obtain plasma-treated PVC shredded material. Pulse shearing is performed on plasma-treated PVC shreds to obtain recycled PVC.

7. The method according to claim 6, characterized in that, The process of plasticizing homogenized PVC scrap to obtain plasticized PVC scrap includes: Modified nanocellulose aerogel fragments loaded with environmentally friendly plasticizers were mixed with homogenized PVC crushed material to obtain a mixture; The mixture is microwave irradiated to obtain plasticized PVC shredded material.

8. The method according to claim 1, characterized in that, The PVC recycled material is modified to obtain PVC padding material, comprising: Multi-stage pore activation pretreatment of recycled PVC materials; Graft modification reaction was carried out on the activated pretreated PVC recycled material to obtain PVC underlay material.

9. The method according to claim 8, characterized in that, The multi-stage pore activation pretreatment of recycled PVC includes: The recycled PVC material is immersed in a composite fluid formed by mixing supercritical CO2 and ionic liquids [EMIM][DEP] and treated under supercritical conditions. The pressure of PVC recycled material treated under supercritical conditions is reduced.

10. The method according to claim 8, characterized in that, The grafting modification reaction of the activated pretreated PVC recycled material to obtain PVC underlay material includes: The activated pretreated recycled PVC material is heated in an inert atmosphere; Modified monomers are introduced into heated recycled PVC material, and a free radical initiator is added simultaneously to initiate a grafting reaction. After the reaction is completed, PVC padding material is obtained.

Images