Recyclable polyurethane with double dynamic bonds, preparation method and extrusion reprocessing method
By introducing recyclable polyurethane materials with dual dynamic bonds, and utilizing imine bonds and photodimerization reactions, the problem of difficult reprocessing of traditional polyurethane materials is solved, enabling continuous extrusion processing and optimized mechanical properties, making it suitable for industrial applications.
Patent Information
- Application Number
- CN202511636488.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-10
- Publication Date
- 2026-02-06
AI Technical Summary
Traditional polyurethane materials are difficult to reprocess and recycle due to irreversible chemical bonds, making it difficult to achieve continuous processing such as injection molding and extrusion, which limits their widespread use.
By introducing dual dynamic bonds, recyclable polyurethane is synthesized using chain extenders containing anthracene and imine bonds. Utilizing the dynamic exchange properties of imine bonds and photodimerization reaction properties, a reversible crosslinking structure is constructed under ultraviolet light irradiation, enabling continuous extrusion processing.
A reversible cross-linked structure for polyurethane materials was achieved, optimizing mechanical properties, meeting the requirements of continuous extrusion processing, simplifying the preparation process, reducing costs, and making it suitable for industrial production.
Smart Images
Figure CN121471484A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer polyurethane materials technology, specifically to recyclable polyurethane with dual dynamic bonds and its preparation method and extrusion reprocessing method. Background Technology
[0002] Polyurethane elastomer, abbreviated as PU, is an essential polymer material in various applications due to its oil resistance, wear resistance, low-temperature resistance, and aging resistance, combined with high hardness and excellent elasticity. It continues to be the subject of in-depth research. Currently, PU is widely used in many areas of daily life, such as home furnishings, construction, daily necessities, transportation, and home appliances. Despite its many advantages, the irreversible chemical bonds in traditionally designed PU materials make reprocessing and recycling difficult. Because PU waste is difficult to degrade, the large-scale use and consumption of PU materials are increasingly burdening the environment. Therefore, developing efficient recycling and reuse technologies for PU materials has become a research focus in recent years.
[0003] To improve the recyclability of polyurethane, existing technologies commonly employ the introduction of chain extenders or crosslinking agents containing dynamic covalent bonds during polyurethane preparation. These dynamic covalent bonds, such as disulfide bonds, imine bonds, acylhydrazone bonds, diselenoses, and Diels-Alder bonds, can break and reconnect under conditions such as hot pressing, thereby enabling the recycling and reuse of polyurethane. However, although these methods achieve recycling to some extent, in most cases, dynamically crosslinked polyurethane is limited by viscoelasticity and flowability during reprocessing. Most reprocessing methods are hot pressing, which cannot be implemented using traditional continuous processing techniques such as injection molding and extrusion, hindering widespread adoption. Summary of the Invention
[0004] To address the limitations of continuous processing difficulties in the recycling of existing polyurethane materials, this invention provides a recyclable polyurethane with dual dynamic bonds, its preparation method, and its extrusion reprocessing method.
[0005] This invention utilizes the synergistic regulation of dual dynamic bonds to control the viscoelasticity and flowability of materials, meeting the requirements of continuous processing techniques such as extrusion and injection molding. This promotes the industrial application of dynamically cross-linked polyurethane materials. Furthermore, this invention also pursues simplicity and cost-effectiveness in the preparation process to meet the needs of environmental protection and sustainable development.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows.
[0007] The first aspect of this invention provides a method for preparing recyclable polyurethane with dual dynamic bonds, comprising the following steps: Diol, diisocyanate, and chain extender are mixed uniformly in a solvent, then heated to remove the solvent and react to form a recyclable polyurethane material. The recyclable polyurethane material is then photocrosslinked under ultraviolet light irradiation to construct a reversible crosslinked structure, resulting in a recyclable polyurethane with dual dynamic bonds. The chain extender is a chain extender containing photodimer groups and imine bonds. The molar ratio of the sum of the molar amounts of the diol and the chain extender to the molar amount of the diisocyanate is 1:1.
[0008] Preferably, the photodimerizing group is any one of anthracene, coumarin, chalcone, or a derivative thereof.
[0009] This invention introduces two dynamic chemical bonds into the polyurethane molecular chain and synthesizes recyclable polyurethane with dual dynamic bonds by using a chain extender containing anthracene and imine bonds. By utilizing the dynamic exchange characteristics of imine bonds and the dimerization reaction characteristics of photodimer groups in the recyclable polyurethane, the recycling and reprocessing performance of the recyclable polyurethane can be controlled, enabling continuous extrusion processing and facilitating its widespread use.
[0010] This invention optimizes mechanical properties by irradiating recyclable polyurethane materials with 365nm ultraviolet light for a certain period of time to construct a reversible cross-linked structure.
[0011] A preferred method for preparing recyclable polyurethane materials includes the following steps: Diol, diisocyanate, and chain extender are mixed evenly in a solvent, then heated to remove the solvent and react to form a recyclable polyurethane material; or, diol and diisocyanate are dissolved in a solvent and reacted to prepare a polyurethane oligomer; then a chain extender is added, and then heated to remove the solvent and react to form a recyclable polyurethane material.
[0012] Preferably, the chain extender has the structural formula shown in formula (I): ; Wherein, R1 is a C3-C5 pentaalkyl group; R2 is any one of anthracene, coumarin, chalcone, or a derivative thereof.
[0013] Preferably, the chain extender is prepared by reacting an amino-containing diol monomer with an aldehyde monomer represented by formula (II) to obtain the chain extender represented by formula (I); the specific chemical reaction formula is as follows: .
[0014] Preferably, the amino-containing diol monomer is at least one selected from 3-aminoglycerol, 2-amino-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, 4-amino-1,2-butanediol, 2-amino-1,3-butanediol, and 2-amino-1,5-pentanediol.
[0015] Preferably, the aldehyde monomer represented by formula (II) is any one of anthracene formaldehyde, coumarin-6-carboxaldehyde, and chalcone-4-carboxaldehyde.
[0016] Preferably, the temperature at which the solvent is removed by heating is 40°C to 100°C.
[0017] Preferably, the diol is at least one selected from polyether diol, polytetrahydrofuran diol, polycaprolactone diol, and alkyl diol.
[0018] Preferably, the diisocyanate is at least one of 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate and 4,4'-diphenylmethane diisocyanate, or an oligomer of any one of them containing two isocyanate groups.
[0019] Preferably, the solvent is any one of acetone, tetrahydrofuran, chloroform, dichloromethane, dimethyl sulfoxide, 1,4-dioxane, N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone, benzene, toluene, and xylene.
[0020] Preferably, the conditions for irradiation under ultraviolet light are: wavelength of 365nm and irradiation time of 0.5min to 20min.
[0021] A second aspect of the present invention provides a recyclable polyurethane with dual dynamic bonds, prepared using the method described in the first aspect.
[0022] A third aspect of the present invention provides a method for extruding and reprocessing recyclable polyurethane with dual dynamic bonds, comprising the following steps: The recyclable polyurethane with dual dynamic bonds described in the second aspect is extruded at 150°C to 170°C to obtain reprocessed granules.
[0023] In this invention, the extrusion process is carried out in an extruder. The fragments or granules of photocrosslinked recyclable polyurethane are added to the extruder and extruded at a temperature above 150°C to obtain reprocessed granules.
[0024] The beneficial effects of this invention are: 1. This invention introduces two dynamic chemical bonds into the polyurethane molecular chain, synthesizing recyclable polyurethane with dual dynamic bonds using chain extenders containing anthracene and imine bonds. By utilizing the dynamic exchange characteristics of the imine bonds and the dimerization characteristics of the photo-induced dimerization groups in the recyclable polyurethane, the recycling and reprocessing performance of the recyclable polyurethane is controlled, enabling continuous extrusion processing and facilitating widespread application. Furthermore, by irradiating the recyclable polyurethane material under ultraviolet light, a reversible cross-linked structure can be constructed, optimizing its mechanical properties.
[0025] 2. This invention provides a highly efficient and simple method for preparing recyclable polyurethane with dual dynamic bonds. By precisely adjusting the molar ratio of the sum of the diol and the chain extender to the molar ratio of the diisocyanate to 1:1, the structure and properties of the polyurethane can be precisely controlled, which greatly facilitates the customization of material properties.
[0026] 3. The method of the present invention completely eliminates the use of traditional catalysts such as metal catalysts or photoinitiators, thereby effectively avoiding the problem of toxic residues. The overall production process is environmentally friendly and non-toxic, providing users with safer and more reliable products.
[0027] 4. The present invention uses a solvent reaction method, which not only ensures the high efficiency of the reaction, but also greatly improves the stability and controllability of the production process, making it very suitable for large-scale industrial production.
[0028] 5. This invention uses the synergistic regulation of dual dynamic bonds to control the viscoelasticity and flowability of polyurethane materials, enabling them to meet the requirements of continuous extrusion processing. Polyurethane can be recycled and reused through extrusion reprocessing.
[0029] 6. The preparation method of the present invention is simple to operate, the raw materials are inexpensive and readily available, and the cost is low, so it can be widely applied to existing polyurethane systems. Attached Figure Description
[0030] Figure 1 The chain extender containing anthracene and imine bonds prepared in Example 1 1 H NMR spectrum.
[0031] Figure 2 The stress-strain curves are for the recyclable polyurethane materials prepared in Examples 9 to 12 before photocrosslinking.
[0032] Figure 3 Stress-strain curves of recyclable polyurethane prepared at different photocrosslinking times.
[0033] Figure 4 This is a photograph of the recycled polyurethane granules obtained by extrusion reprocessing in Example 15. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0035] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0036] Currently, most dynamically cross-linked polyurethanes (PUs) exhibit high viscoelasticity and poor flowability, limiting their application to hot pressing and hindering their ability to be continuously injection molded or extruded like thermoplastics. Therefore, enabling PU to undergo traditional continuous processing, based on the construction of a dynamically cross-linked structure for recycling, is a necessary condition for its widespread adoption.
[0037] The technical solution of the present invention will be further described below through specific embodiments.
[0038] In the following embodiments, unless otherwise specified, the methods described are conventional methods; and unless otherwise specified, the reagents and materials described are commercially available.
[0039] Example 1 A method for preparing a chain extender containing anthracene and imine bonds includes the following steps: 2-Aminoglycerol was reacted with anthracene formaldehyde at a molar ratio of 1:1 at room temperature for 24 hours to obtain a chain extender containing anthracene and imine bonds. The specific reaction equation is as follows: .
[0040] The chain extender prepared in Example 1 1 H NMR spectrum, such as Figure 1 As shown.
[0041] Example 2 A method for preparing a chain extender containing anthracene and imine bonds includes the following steps: 2-Amino-2-methyl-1,3-propanediol was reacted with anthracene formaldehyde at a molar ratio of 1:1 at room temperature for 24 hours to obtain a chain extender containing anthracene and imine bonds.
[0042] Example 3 A method for preparing a chain extender containing anthracene and imine bonds includes the following steps: 2-Amino-1,3-butanediol was reacted with anthracene formaldehyde at a molar ratio of 1:1 at room temperature for 24 hours to obtain a chain extender containing anthracene and imine bonds.
[0043] Example 4 A method for preparing a chain extender containing anthracene and imine bonds includes the following steps: 2-Amino-1,5-pentanediol was reacted with anthracene formaldehyde at a molar ratio of 1:1 at room temperature for 24 hours to obtain a chain extender containing anthracene and imine bonds.
[0044] Example 5 A method for preparing a chain extender containing anthracene and imine bonds includes the following steps: 4-Amino-1,2-Butanediol and anthracene formaldehyde were reacted at a molar ratio of 1:1 at room temperature for 24 hours to obtain a chain extender containing anthracene and imine bonds.
[0045] Example 6 A method for preparing a chain extender containing anthracene and imine bonds includes the following steps: 3-Aminoglycerol was reacted with anthracene formaldehyde at a molar ratio of 1:1 at room temperature for 24 hours to obtain a chain extender containing anthracene and imine bonds.
[0046] Example 7 A method for preparing a chain extender containing coumarin and imine bonds includes the following steps: 2-Aminoglycerol was reacted with coumarin-6-carboxaldehyde at a molar ratio of 1:1 at room temperature for 24 hours to obtain a chain extender containing coumarin and imine bonds. The specific reaction equation is as follows:
[0047] .
[0048] Example 8 A method for preparing a chain extender containing chalcone and imine bonds includes the following steps: 2-Aminoglycerol was reacted with chalcone-4-carboxaldehyde at a molar ratio of 1:1 at room temperature for 24 hours to obtain a chain extender containing chalcone and imine bonds. The specific reaction equation is as follows:
[0049] .
[0050] Examples 1 through 6 all involved the preparation of chain extenders containing anthracene and imine bonds through the reaction of amino-containing diol monomers with photodimerizable aldehyde groups. 1 ¹H NMR spectra confirmed the successful synthesis of the corresponding chain extenders containing anthracene and imine bonds. Example 7 prepared a chain extender containing coumarin and imine bonds by reacting an amino-containing diol monomer with coumarin-6-carboxaldehyde; Example 8 prepared a chain extender containing chalcone and imine bonds by reacting an amino-containing diol monomer with chalcone-4-carboxaldehyde. The chain extenders containing photodimerization-capable groups and imine bonds prepared in Examples 1 to 8 can all be used to prepare recyclable polyurethanes with double dynamic bonds.
[0051] The following example uses the chain extender containing anthracene and imine bonds prepared in Example 1 to prepare recyclable polyurethane with double dynamic bonds. The prepared recyclable polyurethane is then extruded and reprocessed to prepare reprocessed granules.
[0052] In the following examples, the molecular weight of polytetrahydrofuran diol is 1000.
[0053] Example 9 A method for preparing recyclable polyurethane with dual dynamic bonds includes the following steps: The chain extender containing anthracene and imine bonds prepared in Example 1, 4,4'-dicyclohexylmethane diisocyanate, and polytetrahydrofuran diol (M=1000) were dissolved in 20 mL of tetrahydrofuran at a molar ratio of 1:2:1 and reacted at 40 °C for 12 hours. The mixture was then dried in a vacuum oven at 40 °C for 12 hours to obtain a recyclable polyurethane material, denoted as PUAn-1.
[0054] Recyclable polyurethane material was photocrosslinked for 2 minutes under 365nm ultraviolet light irradiation to construct a reversible crosslinked structure, thus obtaining recyclable polyurethane with double dynamic bonds.
[0055] Example 10 A method for preparing recyclable polyurethane with dual dynamic bonds includes the following steps: The chain extender containing anthracene and imine bonds prepared in Example 1, 4,4'-dicyclohexylmethane diisocyanate, and polytetrahydrofuran diol (M=1000) were dissolved in 20 mL of tetrahydrofuran at a molar ratio of 1:3:2, and reacted at 40 °C for 12 hours. The mixture was then dried in a vacuum oven at 40 °C for 12 hours to obtain a recyclable polyurethane material, denoted as PUAn-2.
[0056] Recyclable polyurethane material was photocrosslinked for 2 minutes under 365nm ultraviolet light irradiation to construct a reversible crosslinked structure, thus obtaining recyclable polyurethane with double dynamic bonds.
[0057] Example 11 A method for preparing recyclable polyurethane with dual dynamic bonds includes the following steps: The chain extender containing anthracene and imine bonds prepared in Example 1, 4,4'-dicyclohexylmethane diisocyanate, and polytetrahydrofuran diol (M=1000) were dissolved in 20 mL of tetrahydrofuran at a molar ratio of 1:4:3, and reacted at 40°C for 12 hours. The mixture was then dried in a vacuum oven at 40°C for 12 hours to obtain the recyclable polyurethane material, PUAn-3.
[0058] Recyclable polyurethane material was photocrosslinked for 2 minutes under 365nm ultraviolet light irradiation to construct a reversible crosslinked structure, thus obtaining recyclable polyurethane with double dynamic bonds.
[0059] Example 12 A method for preparing recyclable polyurethane with dual dynamic bonds includes the following steps: The chain extender containing anthracene and imine bonds prepared in Example 1, 4,4'-dicyclohexylmethane diisocyanate, and polytetrahydrofuran diol (M=1000) were dissolved in 20 mL of tetrahydrofuran at a molar ratio of 1:5:4, and reacted at 40°C for 12 hours. The mixture was then dried in a vacuum oven at 40°C for 12 hours to obtain the recyclable polyurethane material, PUAn-4.
[0060] Recyclable polyurethane material was photocrosslinked for 2 minutes under 365nm ultraviolet light irradiation to construct a reversible crosslinked structure, thus obtaining recyclable polyurethane with double dynamic bonds.
[0061] The stress-strain characteristic properties of the recyclable polyurethane materials prepared in Examples 9 to 12 before photocrosslinking were tested, and the results are as follows: Figure 2 As shown in Table 1.
[0062] Figure 2 The stress-strain curves are for the recyclable polyurethane materials prepared in Examples 9 to 12 before photocrosslinking.
[0063] Table 1 Mechanical property data of recyclable polyurethane materials prepared before photocrosslinking Depend on Figure 2 As can be seen from the results in Table 1, 4,4'-dicyclohexylmethane diisocyanate (H 12 MDI (diisocyanate): As a diisocyanate, it is the main component constituting the hard segment of polyurethane, responsible for the material's strength, rigidity, and thermal stability. Polytetrahydrofuran diol (PTHF): As a long-chain diol, it is the main component constituting the soft segment of polyurethane. The soft segment is responsible for the material's flexibility, elasticity, and elongation. In this invention, by adjusting the ratio and structure of hard and soft segments in the recyclable polyurethane material, the tensile strength, elongation at break, Young's modulus, and toughness of the recyclable polyurethane material can be adjusted. Specifically, from PUAn-1 to PUAn-4, the recyclable polyurethane material is adjusted from a state of high strength, high rigidity, and medium elongation to a state of low strength, high elasticity, and ultra-high elongation.
[0064] Example 13 A method for preparing recyclable polyurethane with dual dynamic bond crosslinking includes the following steps: The chain extender containing anthracene and imine bonds prepared in Example 1, 4,4'-dicyclohexylmethane diisocyanate, and polytetrahydrofuran diol (M=1000) were dissolved in 20 mL of tetrahydrofuran at a molar ratio of 1:4:3, and reacted at 40°C for 12 hours. The mixture was then dried in a vacuum oven at 40°C for 12 hours to obtain a recyclable polyurethane material, designated PUAn-3.
[0065] Recyclable polyurethane material was photocrosslinked for 0.5 min under 365 nm ultraviolet light irradiation to construct a reversible crosslinked structure, thus obtaining recyclable polyurethane with double dynamic bonds.
[0066] Example 14 A method for preparing recyclable polyurethane with dual dynamic bond crosslinking includes the following steps: The chain extender containing anthracene and imine bonds prepared in Example 1, 4,4'-dicyclohexylmethane diisocyanate, and polytetrahydrofuran diol (M=1000) were dissolved in 20 mL of tetrahydrofuran at a molar ratio of 1:4:3, and reacted at 40°C for 12 hours. The mixture was then dried in a vacuum oven at 40°C for 12 hours to obtain a recyclable polyurethane material, designated PUAn-3.
[0067] Recyclable polyurethane material was photocrosslinked for 1 min under 365 nm ultraviolet light irradiation to construct a reversible crosslinked structure, thus obtaining recyclable polyurethane with double dynamic bonds.
[0068] The recyclable polyurethane PUAn-3 with double dynamic bonds prepared before photocrosslinking in Example 11, i.e., the sample with 0 min of photocrosslinking, is denoted as UV-0min; the recyclable polyurethane with double dynamic bonds prepared after photocrosslinking in Example 11 is denoted as UV-2min; the recyclable polyurethane with double dynamic bonds prepared after photocrosslinking in Example 13 is denoted as UV-0.5min; and the recyclable polyurethane with double dynamic bonds prepared after photocrosslinking in Example 14 is denoted as UV-1min. Stress-strain characteristic performance tests were performed on the samples with UV-0min, UV-0.5min, UV-1min, and UV-2min. The results are as follows: Figure 3 As shown in Table 2.
[0069] Figure 3 Stress-strain curves of recyclable polyurethane prepared at different photocrosslinking times.
[0070] Table 2 Mechanical property data of recyclable polyurethane at different photocrosslinking times Depend on Figure 3As can be seen from the results in Table 2, the embodiments of the present invention successfully constructed a reversible cross-linked structure by irradiating recyclable polyurethane material with 365nm ultraviolet light, and optimized the mechanical properties of the material, especially its strength and toughness. The optimal photocrosslinking time was 2 min under the experimental conditions.
[0071] Example 15 A method for extruding and reprocessing recyclable polyurethane with dual dynamic bonds, comprising the following steps: The fragments or granules of recyclable polyurethane with double dynamic bonds prepared by photocrosslinking in Example 11 were added to an extruder and extruded at 160°C and 50 rpm to obtain recycled polyurethane granules.
[0072] Figure 4 This is a photograph of the recycled polyurethane granules obtained by extrusion reprocessing in Example 15.
[0073] This invention introduces two dynamic chemical bonds into the polyurethane molecular chain, and utilizes the dynamic exchange characteristics of imine bonds and the dimerization characteristics of anthracene in the polyurethane material synthesized by an anthracene and imine bond chain extender to regulate the recycling and reprocessing performance of the polyurethane material, enabling continuous extrusion processing and facilitating its widespread use.
[0074] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing recyclable polyurethane with dual dynamic bonds, characterized in that, Includes the following steps: Diol, diisocyanate and chain extender are used as raw materials, mixed evenly in a solvent, then heated to remove the solvent and react to form a recyclable polyurethane material. Recyclable polyurethane materials were photocrosslinked under ultraviolet light irradiation to construct a reversible crosslinked structure, resulting in recyclable polyurethane with dual dynamic bonds. The chain extender is a chain extender containing a photodimer group and an imine bond; the photodimer group is any one of anthracene, coumarin, chalcone, or a derivative thereof; The ratio of the sum of the molar amounts of the diol and the chain extender to the molar amount of the diisocyanate is 1:
1.
2. The method for preparing recyclable polyurethane with dual dynamic bonds according to claim 1, characterized in that, A method for preparing recyclable polyurethane materials includes the following steps: Diol, diisocyanate and chain extender are mixed evenly in a solvent, then heated to remove the solvent and react to form a recyclable polyurethane material. Alternatively, diols and diisocyanates can be dissolved in a solvent and reacted to prepare polyurethane oligomers; then chain extenders can be added, followed by heating to remove the solvent and reacting to form a recyclable polyurethane material.
3. The method for preparing recyclable polyurethane with dual dynamic bonds according to claim 1, characterized in that, The chain extender has the structural formula shown in formula (I): ； Wherein, R1 is a C3-C5 pentaalkyl group; R2 is any one of anthracene, coumarin, chalcone, or a derivative thereof.
4. The method for preparing recyclable polyurethane with dual dynamic bonds according to claim 3, characterized in that, The chain extender is prepared by reacting an amino-containing diol monomer with an aldehyde monomer represented by formula (II) to obtain the chain extender represented by formula (I); the specific chemical reaction formula is as follows: 。 5. The method for preparing recyclable polyurethane with dual dynamic bonds according to claim 4, characterized in that, The amino-containing diol monomer is at least one selected from 3-aminoglycerol, 2-amino-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, 4-amino-1,2-butanediol, 2-amino-1,3-butanediol and 2-amino-1,5-pentanediol. The aldehyde monomer represented by formula (II) is any one of anthracene formaldehyde, coumarin-6-carboxaldehyde, and chalcone-4-carboxaldehyde.
6. The method for preparing recyclable polyurethane with dual dynamic bonds according to claim 1, characterized in that, The temperature at which the solvent is removed by heating is 40℃~100℃.
7. The method for preparing recyclable polyurethane with dual dynamic bonds according to claim 1, characterized in that, The diol is at least one of polyether diol, polytetrahydrofuran diol, polycaprolactone diol, and alkyl diol; The diisocyanate is at least one of 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, toluene diisocyanate and 4,4'-diphenylmethane diisocyanate, or an oligomer of any one of them containing two isocyanate groups. The solvent is any one of acetone, tetrahydrofuran, chloroform, dichloromethane, dimethyl sulfoxide, 1,4-dioxane, N,N'-dimethylformamide, N,N'-dimethylacetamide, N-methylpyrrolidone, benzene, toluene, and xylene.
8. The method for preparing recyclable polyurethane with dual dynamic bonds according to claim 1, characterized in that, The conditions for irradiation under ultraviolet light are: wavelength of 365nm and irradiation time of 0.5min to 20min.
9. A recyclable polyurethane with dual dynamic bonds, characterized in that, It is prepared by the method described in any one of claims 1 to 8.
10. A method for extruding and reprocessing recyclable polyurethane with dual dynamic bonds, characterized in that, Includes the following steps: The recyclable polyurethane with dual dynamic bonds as described in claim 9 is extruded at 150°C to 170°C to obtain reprocessed granules.