Production process of double-opening middle armrest coating piece

Abstract

The invention relates to the technical field of automotive interiors, and discloses a double-opening middle armrest coating part production process which comprises the following steps: preparing a dynamic covalent cross-linking matrix, mixing 50-60 parts of polyurethane-polyurea copolymer and 10-15 parts of double-dynamic thiol-olefinic bond cross-linking agent through high-temperature blending reaction, and continuously stirring to form a dynamic cross-linking network; and dispersing the nano filler, adding 3-7 parts of silicon dioxide nanoparticles into the blending system, and stirring by using a high-shear dispersion machine to uniformly disperse the silicon dioxide nanoparticles. A reversible cross-linked network is constructed through high-temperature blending, the material can be spontaneously recombined after being damaged, the effect of remarkably improving durability and fatigue resistance is achieved, a traditional material is prone to irreversible damage and difficult to repair in long-term use, a cross-linked matrix can dynamically adjust the cross-linking degree under the high-temperature or catalytic condition, and the durability and fatigue resistance of the material are improved. The problem that in the prior art, materials cannot be recovered after being broken is solved, and the service life and stability of products are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive interior decoration, and specifically to a production process for a double-opening middle armrest covering member. Background Art

[0002] In the manufacturing of automotive interior parts, as an important functional and aesthetic component, the armrest covering member poses higher requirements for the durability, comfort, and intelligent performance of the material. Currently, the mainstream armrest covering materials on the market mostly adopt polymer materials such as polyurethane, polyurea, or thermoplastic elastomer, and improve the mechanical properties through static cross-linking or physical modification. However, there are many technical bottlenecks in the long-term use of such materials, making it difficult to meet the development needs of the new generation of automotive intelligence and durability.

[0003] Existing armrest covering members mainly adopt a static cross-linked matrix, and its molecular structure is irreversible after forming, resulting in the material being prone to microdamage under long-term fatigue loads and being difficult to repair. Once the material is subjected to external forces during use to form cracks or fractures, the repair methods mainly rely on externally coating a repair agent or locally heating to induce a cross-linking reaction. However, such repair methods have limitations: the coating repair agent is often difficult to penetrate into the microcrack area inside the material, resulting in incomplete repair, while local heating repair requires additional energy consumption and may affect the overall performance of the material. In addition, the static cross-linked polymer is prone to degradation in a high-temperature environment, further shortening the product life.

[0004] In addition, the existing microcapsule repair technology usually adopts a single-phase capsule structure. When the material is damaged, the release of the repair agent often has a lag, resulting in crack propagation beyond the repairable range and reducing the overall reliability of the material.

[0005] Traditional shape memory polymers (SMPs) usually rely on external thermal triggers to restore the material from a deformed state to its original shape. However, the shape recovery of such materials often requires a high trigger temperature or mechanical stimulation, which is not suitable for complex structures or parts that are difficult to access. At the same time, due to the fixed cross-linked structure inside the material, the reversibility of shape recovery is poor, and fatigue failure is prone to occur after multiple deformations. In addition, the existing shape memory materials are difficult to achieve remote control, and their recovery mechanism relies on overall heating, lacking the ability of precise regulation. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the present invention provides a production process for a double-opening middle armrest covering member, which solves the problems of poor durability of the existing armrest covering member material, low self-repair efficiency, and limited shape memory regulation.

[0007] To achieve the above objectives, the present invention is realized through the following technical solutions: A production process for a double-opening middle armrest covering member, including: Preparation of a dynamic covalent cross-linked matrix. Through a high-temperature blending reaction, 50 - 60 parts of a polyurethane-polyurea copolymer are mixed with 10 - 15 parts of a double-dynamic thiol-ene cross-linking agent, and continuous stirring is carried out to form a dynamic cross-linked network; Dispersion of nano-fillers. 3 - 7 parts of silica nanoparticles are added to the blending system, and a high-shear dispersing machine is used for stirring to make them evenly dispersed; Synthesis of micro-scale self-healing liquid capsules. Using the double-emulsion polymerization method, 10 - 15 parts of polydimethylsiloxane are used as the core, and 3 - 5 parts of ultraviolet-curable epoxy resin are used as the shell, and pre-curing is carried out under the condition of ultraviolet light irradiation to form the healing liquid capsules; Preparation of macro-scale reversible deformation materials. Through high-temperature casting, 5 - 10 parts of a shape memory polymer are compounded with 2 - 4 parts of magnetic nanoparticles; Composite material forming process, including: Compression molding; Plasma surface treatment; Ultraviolet curing; Magnetic field-induced repair.

[0008] Further explanation of the above steps. The core of the dynamic covalent cross-linked matrix lies in the reversible covalent bond cross-linking, enabling the material to achieve network reorganization through thermal or chemical stimuli after being deformed by force, thereby improving its fatigue resistance and self-healing ability. The polyurethane-polyurea copolymer provides good mechanical properties and flexibility, while the double-dynamic thiol-ene cross-linking agent realizes the re-plasticity of the cross-linked network through the reversible thiol-ene reaction, enabling the material to recover its original state after fracture and improving the overall durability and service life.

[0009] The addition of silica nanoparticles helps to improve the mechanical strength, wear resistance, and anti-aging performance of the material. However, due to the easy agglomeration of nanoparticles, it is necessary to use a high-shear dispersing machine for sufficient dispersion to form a uniformly distributed strengthening network in the matrix, thereby improving the overall uniformity and stability of the composite material.

[0010] The design of the micro-scale self-healing liquid capsules is based on microcapsule technology. When the material is damaged, the liquid capsules rupture, and the internal polydimethylsiloxane flows out and fills the cracks, and a cured layer is formed under the action of environmental oxygen or a catalyst, thereby realizing the self-healing function. The ultraviolet-curable epoxy resin is used as the shell material, providing good chemical resistance and mechanical stability during production and application, and at the same time ensuring that the healing liquid does not leak under normal conditions and only plays a role when damaged.

[0011] The main feature of the shape memory polymer is its ability to undergo reversible deformation at a specific temperature, enabling the middle armrest covering to restore its original shape under a certain stress. The addition of magnetic nanoparticles allows the material to respond under an external magnetic field and achieve remote control and repair, enhancing its intelligent performance.

[0012] Molding. The molding process can ensure the uniformity and stability of the internal structure of the material. Through reasonable temperature and pressure control, the components are fully cross-linked, improving the mechanical properties and durability of the composite material.

[0013] Plasma surface treatment. Plasma surface treatment is used to improve the surface activity of the composite material and enhance the bonding strength of the coating or adhesive layer. Through the action of oxygen or nitrogen plasma, micro-etching occurs on the material surface, and at the same time, polar functional groups are introduced to improve the adhesion of the coating or adhesive.

[0014] UV curing. UV curing is used to rapidly cure the surface coating, improving scratch resistance and chemical resistance. After UV irradiation, the photoinitiator is activated, initiating the cross-linking reaction of monomers or oligomers, rapidly hardening the material surface and enhancing the durability of the final product.

[0015] Magnetic field-induced repair. The magnetic field-induced repair technology utilizes the responsiveness of magnetic nanoparticles to an external magnetic field. At the damaged part of the material, the repair mechanism is activated through local heating or mechanical stimulation, enabling the material to self-repair cracks or deformations without the need for external chemical agents, improving its service life and intelligent response ability.

[0016] Preferably, the preparation of the dynamic covalent cross-linked matrix adopts a high-temperature blending reaction at 180 - 200 °C, and the continuous stirring time is 3 - 5 h. The polyurethane-polyurea copolymer is prepared by the reaction of isocyanate and polyether polyol, and the dual dynamic thiol-ene cross-linking agent is a thiol-functional group modified polymer.

[0017] Further explanation of the above steps: The high-temperature blending reaction enables the polymer molecular chains to fully expand and cross-link, forming a high-elastic network structure, thereby ensuring that the material has excellent mechanical properties and self-repair characteristics at different temperatures.

[0018] Preferably, the nano-filler dispersion process is treated with a high-shear disperser, the stirring speed is 5000 - 8000 rpm, and the stirring time is 30 - 45 min.

[0019] Further explanation of the above steps: The high-shear dispersion process ensures the uniform dispersion of nano-particles in the polymer matrix, preventing performance degradation caused by particle agglomeration, thereby enhancing the mechanical strength and thermal stability of the overall material.

[0020] Preferably, the micron - level self - healing liquid capsules are synthesized by double - emulsion polymerization and cured under the condition of ultraviolet curing wavelength of 365 - 405 nm, with the curing time of 10 - 20 min. The polydimethylsiloxane is hydroxyl - terminated polydimethylsiloxane, and the ultraviolet - curable epoxy resin is prepared by mixing bisphenol A epoxy resin and photo - initiator.

[0021] For further explanation of the above steps, hydroxyl - terminated polydimethylsiloxane can form a flexible network during the self - healing process, improving the toughness and durability of the material, while the rapid curing property of the photo - curable epoxy resin makes the repair process more efficient.

[0022] Preferably, the macro - level reversible deformation material is prepared by high - temperature casting molding, with the temperature range of 150 - 180 °C and the casting time of 5 - 10 min. The shape - memory polymer is polylactic acid or polyurethane - based shape - memory material, and the magnetic nanoparticles are iron oxide nanoparticles.

[0023] For further explanation of the above steps, the casting process ensures uniform forming of the material, improving the overall mechanical properties and shape - memory effect, while the high magnetic responsiveness of iron oxide nanoparticles enables the material to quickly recover its shape under the action of a magnetic field.

[0024] Preferably, the temperature range for the compression molding is 120 - 180 °C, the pressure range is 5 - 15 MPa, and the molding time is 30 - 60 min. During the compression molding process, heating and pressurization are used for curing.

[0025] For further explanation of the above steps, the compression molding process densifies the internal structure of the material, improving the comprehensive performance of the product.

[0026] Preferably, the power of the plasma surface treatment is 50 - 100 W, the frequency is 20 - 40 kHz, and the treatment gas is oxygen or nitrogen.

[0027] For further explanation of the above steps, oxygen plasma enhances the surface activity, improving the subsequent coating or bonding effect.

[0028] Preferably, the wavelength of the ultraviolet light curing is 365 - 405 nm, the time is 10 - 20 min, and the light - curing device uses an LED light source.

[0029] For further explanation of the above steps, the LED light source has uniform energy, improving the curing efficiency and surface finish.

[0030] Preferably, the magnetic - field - induced repair is carried out with a magnetic induction intensity of 80 - 150 mT, and the magnetic field is provided by a permanent magnet or an electromagnetic coil.

[0031] Further description of the above steps: Magnetic field-induced local heating restores the structural integrity of the material.

[0032] Preferably, the mass ratio of the dynamic covalent cross-linked matrix to the microscale liquid capsule self-healing layer is 4:1 to 6:1.

[0033] Further description of the above steps: A reasonable ratio ensures that the material has excellent mechanical strength and self-healing ability.

[0034] The present invention provides a production process for a double-opening middle armrest covering member, which has the following beneficial effects: 1. The present invention constructs a reversible cross-linked network through high-temperature blending, enabling the material to spontaneously reorganize after being damaged, achieving the effect of significantly improving durability and anti-fatigue performance. Compared with the statically cross-linked polyurethane or polyurea systems in the prior art, traditional materials are prone to irreversible damage during long-term use and are difficult to repair. The cross-linked matrix of the present invention can dynamically adjust the cross-linking degree under high temperature or catalytic conditions, overcoming the problem that the materials in the prior art cannot be restored after fracture, and greatly improving the service life and stability of the product.

[0035] 2. The present invention is prepared by the double emulsion polymerization method, enabling the internal repair agent to be automatically released when damage occurs, filling and curing cracks, achieving the technical effect of repairing microcracks without manual intervention. Compared with the prior art solutions that rely on external coating of repair agents or local heating to activate the repair reaction, traditional methods often have low repair efficiency and are difficult to penetrate into the internal microcracks of the material. The liquid capsules of the present invention can release the repair agent at the initial stage of crack propagation, realizing the rapid restoration of the material structure, and significantly enhancing the self-healing ability and ductility.

[0036] 3. The present invention, through the synergistic effect of the shape memory polymer and magnetic nanoparticles, enables the material to restore its original shape under the action of a magnetic field or temperature change, achieving the technical effect of intelligent structural adjustment. In the prior art, traditional shape memory materials often require external mechanical force or high temperature to trigger deformation recovery, which limits the application scenarios and has low control accuracy. The present invention realizes remote control and local reversible deformation through the magnetic response mechanism, breaking through the limitations of traditional materials in deformation repair and improving the adaptability and functionality of the materials.

[0037] 4. The present invention adopts multiple processes such as plasma surface activation, ultraviolet curing, and magnetic field-induced repair, enabling the material to have stronger interfacial bonding force and weather resistance, achieving the technical effect of enhancing the overall stability. Compared with the single physical or chemical modification methods in the prior art, such as surface roughening or chemical coating, traditional processes often have problems such as poor adhesion and easy peeling during long-term use. The present invention, through the synergistic action of multiple means, enables the material surface to have more excellent adhesion and durability, improving the applicability in complex environments. Description of the Drawings

[0038] Figure 1 This is the flowchart of the method of the present invention. Specific embodiments

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] Please refer to the attached Figure 1 : Example 1 Take 50 parts of polyurethane-polyurea copolymer and 15 parts of double dynamic thiol-ene crosslinking agent, put them into a mixing equipment, heat to 185 °C, and stir at high speed for 4 h to form a dynamic crosslinking network. After crosslinking, slowly add 5 parts of silica nanoparticles, and continue to stir for 30 min. Subsequently, adopt high-shear dispersion technology with a rotation speed of 7800 rpm and process for 40 min to make the nanoparticles evenly distributed, improving wear resistance and overall mechanical properties.

[0041] Prepare micron-scale self-healing liquid capsules. Take 12 parts of polydimethylsiloxane and 3 parts of ultraviolet-curable epoxy resin, and coat them by double emulsion polymerization method. The emulsification rotation speed is 900 rpm and the emulsification time is 20 min to form a stable emulsion. Then place it in an ultraviolet light curing equipment with a light wavelength of 390 nm and cure for 15 min to ensure the stability of the liquid capsules and improve the repair ability.

[0042] Prepare the shape memory layer. Take 8 parts of shape memory polymer and 7 parts of iron oxide nanoparticles, fully mix them and heat to 160 °C, and cast for 8 min to obtain a uniform composite layer. Subsequently, compound it with the matrix and adopt molding under pressure at a temperature of 150 °C, a pressure of 12 MPa, and a pressure holding time of 50 min.

[0043] The surface is treated by plasma with a power of 80 W, nitrogen plasma, and a treatment time of 3 min to improve the surface adhesion. Subsequently, ultraviolet curing is carried out with an LED light source, a wavelength of 400 nm, and a light irradiation time of 12 min. The magnetic field-induced repair test shows that the magnetic induction intensity is 120 mT, and the crack basically disappears within 1 h, and the repair rate reaches 85%.

[0044] Example 2 Take 55 parts of polyurethane-polyurea copolymer and 10 parts of double dynamic thiol-ene crosslinking agent, put them into a high-temperature mixer, set the temperature to 190 °C, and stir for 3.5 h to make the crosslinking fully stable. Then, slowly add 6 parts of silica nanoparticles, and carry out high-shear dispersion with a rotation speed of 8000 rpm and a stirring time of 30 min to ensure the uniform dispersion of the particles and improve the impact resistance.

[0045] Prepare micron-scale self-healing liquid capsules. Take 10 parts of polydimethylsiloxane and 5 parts of ultraviolet-curable epoxy resin, and perform emulsification using the double emulsion method at an emulsification speed of 1000 rpm for 15 minutes to form stable microcapsules. Then, cure with ultraviolet light at a wavelength of 365 nm for 10 minutes to completely coat the liquid capsules and improve the self-healing ability.

[0046] Fabricate the shape memory layer. Take 6 parts of shape memory polymer and 8 parts of iron oxide nanoparticles, mix them thoroughly, set the temperature at 165 °C, and cast for 6 minutes. Then, co-laminate with the substrate using a molding process at a pressure of 10 MPa and a temperature of 160 °C for 40 minutes.

[0047] Perform surface plasma treatment at a power of 65 W with oxygen plasma acting for 3.5 minutes. Cure with ultraviolet light at a wavelength of 370 nm for 18 minutes. Conduct magnetic field-induced repair testing at a magnetic induction intensity of 100 mT, and the crack is completely repaired with an overall recovery rate of 90%.

[0048] Example 3 Take 52 parts of polyurethane-polyurea copolymer and 13 parts of double dynamic thiol-ene crosslinking agent, place them in a melt mixer, set the temperature at 195 °C, and stir for 4.5 hours until crosslinking is complete. Add 7 parts of silica nanoparticles to enhance the mechanical strength, and use high-shear dispersion at a speed of 7500 rpm and stir for 35 minutes to evenly disperse the filler and improve the structural stability.

[0049] Prepare self-healing liquid capsules. Take 11 parts of polydimethylsiloxane and 3 parts of ultraviolet-curable epoxy resin, and perform emulsification using the double emulsion method at an emulsification speed of 850 rpm for 25 minutes to form uniform microcapsules. Subsequently, cure with ultraviolet light at a light wavelength of 385 nm for 15 minutes to ensure the stability of the liquid capsules.

[0050] Prepare the shape memory layer. Take 7 parts of shape memory polymer and 7 parts of iron oxide nanoparticles, set the temperature at 155 °C, and cast for 10 minutes to form a uniform deformation layer. Subsequently, laminate with the substrate material using a molding process at a temperature of 140 °C, a pressure of 15 MPa, and hold for 60 minutes to obtain the final composite material.

[0051] Perform plasma surface treatment at a power of 90 W with oxygen plasma acting for 5 minutes, cure with ultraviolet light at a wavelength of 390 nm for 10 minutes, conduct magnetic field-induced repair testing at a magnetic induction intensity of 140 mT, and the crack self-healing rate reaches 95%.

[0052] Example 4 Take 53 parts of polyurethane-polyurea copolymer and 12 parts of dual dynamic thiol-olefin crosslinker, put them into mixing equipment, set the temperature to 190°C, stir for 4 hours to form a dense crosslinked structure, add 5 parts of silica nanoparticles, high shear dispersion, speed 7500rpm, stir for 40 minutes to ensure uniform distribution of filler and enhance anti-aging performance.

[0053] To prepare the self-healing liquid capsule, 12 parts of polydimethylsiloxane and 3 parts of UV-curable epoxy resin were taken, and the double emulsion method was used with an emulsification speed of 950 rpm, an emulsification time of 30 min, a UV-curing light wavelength of 380 nm, and a curing time of 12 min to form a stable liquid capsule and improve the repair efficiency.

[0054] To prepare the shape memory layer, 6 parts of shape memory polymer and 6 parts of ferrosoferric oxide nanoparticles were taken, mixed thoroughly, the temperature was set to 165°C, the casting time was 7 minutes, a uniform layer was formed, and then laminated with the substrate, the molding temperature was 150°C, the pressure was 12 MPa, and the pressure was maintained for 50 minutes to finally obtain a composite sheet.

[0055] Plasma surface treatment, power 70W, nitrogen plasma action 4min, UV curing wavelength 400nm, time 15min. Magnetic field induced repair test, magnetic induction intensity 110mT, crack self-repair efficiency reached 88%.

[0056] Comparative Example 1 (corresponding to Example 1) Take 50 parts of polyurethane-polyurea copolymer and 15 parts of dual dynamic thiol-olefin crosslinker, add them into the mixing equipment, set the temperature to 185°C, stir for 4 hours, add 5 parts of silica nanoparticles into the system, use ordinary low-speed stirring (speed 1500rpm), stirring time 40min, and do not use high shear dispersion process.

[0057] To prepare the micron-scale self-healing liquid capsule, 12 parts of polydimethylsiloxane and 3 parts of UV-curable epoxy resin were taken, and the ordinary emulsification method was used with an emulsification speed of 500 rpm for 10 minutes. During the curing stage, an ordinary oven was used to heat to 60°C and cure for 20 minutes. No UV curing process was used.

[0058] To prepare the shape memory layer, 8 parts of shape memory polymer and 7 parts of ferrosoferric oxide nanoparticles were taken, the temperature was set to 160°C, and a common hot press was used for direct pressing without a casting process, and the holding time was 5 minutes.

[0059] After molding, no plasma surface treatment is performed, and the surface roughness is only treated by mechanical grinding. During the UV curing stage, traditional halogen light is used for irradiation, with a wavelength of 430nm and an irradiation time of 30min. The magnetic field induced repair test with a magnetic induction intensity of 80mT is used to detect the self-repair effect.

[0060] Comparative Example 2 (corresponding to Example 2) Take 55 parts of polyurethane-polyurea copolymer and 10 parts of double-dynamic thiol-ene crosslinker, put them into a melt mixer, set the temperature at 190 °C, stir for 3.5 h. Subsequently, add 6 parts of silica nanoparticles, use ordinary stirring equipment, rotate at 2500 rpm, and stir for 20 min. High-shear dispersion technology is not used.

[0061] For the preparation of micro-scale self-healing liquid capsules, take 10 parts of polydimethylsiloxane and 5 parts of ultraviolet-curable epoxy resin, adopt the single-phase emulsification method, rotate at 800 rpm, emulsify for 8 min. For ultraviolet curing, use a low-power light source with a wavelength of 360 nm and a curing time of 5 min.

[0062] For the preparation of the shape memory layer, take 6 parts of shape memory polymer and 8 parts of iron oxide nanoparticles, directly mix them and then use cold pressing to form. Casting treatment is not carried out. The pressing temperature is 120 °C and the holding time is 3 min.

[0063] Do not perform plasma surface treatment, directly perform spray coating treatment. In the ultraviolet curing stage, irradiate with a mercury lamp with a wavelength of 370 nm for 8 min. For the magnetic field-induced repair test, the magnetic induction intensity is 60 mT, and the shape recovery of the material is detected.

[0064] Comparative Example 3 (corresponding to Example 3) Take 52 parts of polyurethane-polyurea copolymer and 13 parts of double-dynamic thiol-ene crosslinker, set the temperature at 195 °C, stir for 4.5 h, add 7 parts of silica nanoparticles, use the ultrasonic dispersion process, with an ultrasonic power of 50 W, and process for 15 min. High-shear dispersion technology is not adopted.

[0065] For the preparation of micro-scale self-healing liquid capsules, take 11 parts of polydimethylsiloxane and 3 parts of ultraviolet-curable epoxy resin, and use the physical mixing method for coating. Stir at a rotation speed of 400 rpm for 5 min. In the curing stage, use thermal curing, set the temperature at 70 °C, and the time is 25 min. Ultraviolet curing is not used.

[0066] For the preparation of the shape memory layer, take 7 parts of shape memory polymer and 7 parts of iron oxide nanoparticles, directly perform powder pressing, without high-temperature casting treatment. The molding temperature is 140 °C, the pressure is 8 MPa, and the pressing time is 2 min.

[0067] In the surface treatment stage, plasma treatment is not adopted, only chemical etching treatment is carried out. In the ultraviolet curing stage, irradiate with a traditional fluorescent lamp with a wavelength of 420 nm for 20 min. For the magnetic field-induced repair test, the magnetic induction intensity is 50 mT, and the crack change of the material is observed.

[0068] Comparative Example 4 (corresponding to Example 4) Take 53 parts of polyurethane-polyurea copolymer and 12 parts of double-dynamic thiol-ene crosslinking agent, put them into a mixer, set the temperature at 190 °C, stir for 4 h, add 5 parts of silica nanoparticles to the system, stir manually for 10 min, and do not use the high-shear dispersion process.

[0069] For the preparation of self-healing liquid capsules, take 12 parts of polydimethylsiloxane and 3 parts of ultraviolet-curable epoxy resin, use the ordinary stirring method, with a stirring rate of 200 rpm for 10 min. The emulsification is insufficient. In the curing stage, use a heating oven, set the temperature at 65 °C for 30 min, and do not use ultraviolet curing.

[0070] For the preparation of the shape memory layer, take 6 parts of shape memory polymer and 6 parts of iron oxide nanoparticles. Do not perform the casting process, and directly use the ordinary injection molding process, set the temperature at 130 °C, and keep the time for 4 min.

[0071] Do not perform plasma surface treatment, only perform sandpaper polishing. In the ultraviolet curing stage, use low-intensity light, with a wavelength of 350 nm and a light irradiation time of 25 min. For the magnetic field-induced repair test, the magnetic induction intensity is 40 mT, and observe the crack evolution of the material.

[0072] Experiment 1: Self-healing ability test Experimental procedure Specimen preparation Select the samples of Example 1 and Comparative Example 1, and cut them into test pieces with dimensions of 50 mm × 10 mm × 2 mm respectively, and try to keep the dimensions consistent as much as possible to reduce errors.

[0073] Number the test pieces to avoid confusion.

[0074] Crack manufacturing Use a scratch tester (model: MCT-101) to scratch a crack with a depth of 200 μm and a length of 10 mm on the surface of the test piece.

[0075] Ensure that the crack directions of each test piece are the same for comparison.

[0076] Repair process Put the test pieces into the magnetic field device, set the magnetic induction intensity to 80 mT, and maintain the ambient temperature at 25 °C.

[0077] Observe the crack changes every 10 min, and use an optical microscope (Leica DM2700M) to take pictures for 60 min.

[0078] Data collection Record the change in crack length and calculate the repair situation.

[0079] Use a scanning electron microscope (SEM) to analyze the microscopic morphology of the repair area and evaluate the repair quality.

[0080] Experimental data Table 1: Comparison of crack repair rates of different specimens Experimental summary The disappearance of cracks is not just physical closure, but more importantly, the reconstruction of the molecular structure. The repair speed of Example 1 is significantly faster. The repair rate exceeds 30% in the first 20 minutes. The rearrangement of dynamic covalent bonds endows the material with self-adaptive repair ability. Once a crack forms, the internal molecular chain segments of the material automatically adjust to fill the damage. In Comparative Example 1, the crack almost stagnates. The low-speed stirring results in uneven distribution of fillers, forming defects. It is difficult for the internal structure of the material to effectively respond to the magnetic field, and the crack propagation cannot be inhibited.

[0081] The curing speed of the liquid capsule also determines the repair efficiency. The epoxy liquid capsule of Example 1 forms a stable network after ultraviolet curing. After the liquid penetrates, it quickly cures to form a solid repair layer. In Comparative Example 1, the liquid capsule prepared by the ordinary emulsification method has a low content release rate and uneven diffusion, resulting in incomplete crack filling. The repair rate is less than 20% in the first 30 minutes, and the final repair rate is less than 30%. This shows that the repair system without ultraviolet curing is difficult to work effectively.

[0082] The microstructure also reveals the differences. The SEM image shows that the crack area of Example 1 tends to be smooth, and the repair area has a high degree of fusion with the matrix, and almost no repair traces can be seen. In Comparative Example 1, the crack boundary is still clear, and the surface of the repair layer is rough, indicating that the repair agent fails to completely fill the crack. The high-shear dispersion process with enhanced magnetic response not only improves the filling ability inside the material but also makes the crack repair more uniform. Repair is not just compensation but also a dynamic structural optimization.

[0083] Experiment 2: Shape memory ability test Experimental steps Specimen preparation Select the samples of Example 2 and Comparative Example 2, and cut them into test pieces with dimensions of 50 mm × 10 mm × 2 mm to ensure consistent dimensions and reduce experimental errors.

[0084] Number the test pieces to avoid confusion.

[0085] Deformation treatment Heat the test piece in a constant temperature water bath at 80 °C for 5 minutes to make it reach the softening state.

[0086] Use a bending fixture to bend the test piece to 90° and hold it for 2 minutes to ensure that the deformation is fully fixed.

[0087] Quickly cool the test piece to room temperature, record the deformation angle, and observe whether the test piece undergoes shape recovery.

[0088] Shape Recovery Test The test piece was placed in a 100 mT magnetic field, and the shape recovery process was observed. The morphology of the test piece was photographed every 5 minutes.

[0089] Calculate the change in the shape recovery angle until the test piece returns to its original shape or no longer changes.

[0090] Use image analysis software to measure the final residual angle and evaluate the shape memory recovery rate.

[0091] Data Analysis Record the recovery time and recovery angle of the test piece, and compare the recovery capabilities of different samples.

[0092] Use a scanning electron microscope (SEM) to analyze the microstructure of the shape memory layer and evaluate the deformation response ability.

[0093] Experimental Data Table 2: Comparison of Shape Recovery Rates of Different Specimens Experimental Summary The deformation recovery of the material is not only due to the effect of temperature, but also the coordinated movement of the internal molecules of the material. In Example 2, the angle recovery is rapid in a short time. It has rebounded within 30° in the first 15 minutes and is almost completely recovered finally. The high-temperature casting process makes the shape memory polymer more evenly distributed and has a stronger ability for the internal molecular chain segments to rearrange. In contrast, in Comparative Example 2, there is still a residual angle of more than 40° even after 25 minutes, and the recovery is blocked. The material formed by cold pressing has a relatively irregular structure and the molecular chain arrangement is not tight enough, resulting in the weakening of the memory effect.

[0094] The influence of magnetic response is also important. The magnetic iron oxide nanoparticles in Example 2 are evenly distributed and quickly generate heat under the action of the magnetic field, causing the local temperature of the material to rise and accelerating the movement of the molecular chain segments. It can be clearly observed in the experiment that after the magnetic field is turned on, the shape recovery process of the test piece in Example 2 is significantly accelerated. In Comparative Example 2, the nanoparticles are unevenly distributed, the magnetothermal effect is weakened, the local heating is insufficient, and the recovery time is prolonged. The synergistic effect of the magnetic induction effect and the material structure determines the quality of the shape memory performance.

[0095] The differences in the microstructure can be visually seen from the SEM images. The shape recovery area of Example 2 is relatively smooth, and there are almost no obvious structural damages on the recovered surface. In Comparative Example 2, there are still obvious deformation marks on the recovered surface, indicating that the resilience ability of the material is limited. Shape memory is not a simple deformation resilience, but a molecular-scale reconstruction process. High-temperature casting improves the activity of the molecular chain segments, and the magnetothermal effect further accelerates the movement of the segments. The combination of the two can create an efficient memory recovery ability.

[0096] Experiment 3: Wear Resistance Test of Materials Experimental Procedures Specimen Preparation Select the samples of Example 3 and Comparative Example 3, and cut them into circular specimens with a diameter of 10 mm, ensuring that the surface is flat without bubbles or obvious defects.

[0097] Number the specimens and measure the initial mass, recording the exact value.

[0098] Wear Resistance Test Use a Taber wear tester (model: CS-10 grinding wheel), set the load to 500 g, the rotation speed to 60 rpm, and test for 5000 revolutions.

[0099] Ensure that the surface of the specimen is in full contact with the grinding wheel to ensure uniform testing.

[0100] During the test, pause every 1000 revolutions to measure the mass loss of the specimen and record the wear situation.

[0101] Data Analysis After the test, clean the residue on the surface of the specimen, measure the final mass, and calculate the total mass loss.

[0102] Use a scanning electron microscope (SEM) to observe the microscopic morphology of the worn area and evaluate the wear resistance difference.

[0103] Experimental Data Table 3: Comparison of Wear Resistance of Different Specimens Experimental Summary The strength of wear resistance does not only depend on the hardness of the material. More importantly, it is the stability of the internal structure. The mass loss of Example 3 is small, and it still maintains a low wear amount after 5000 revolutions. The high-shear dispersion technology enables the uniform distribution of silica nanoparticles, forming a stable reinforcement network inside the material. This network not only improves the overall wear resistance but also enables the material to effectively resist surface damage during friction. Comparative Example 3 shows obvious mass loss and a faster wear rate. The uneven dispersion of particles leads to stress concentration in local areas, resulting in the destruction of the microstructure and thus accelerating the wear of the material.

[0104] The intervention of the repair mechanism further improves the wear resistance. During friction, the self-repairing liquid sacs in Example 3 rupture and fill the damaged areas, forming a protective layer to prevent further damage to the material. This self-adaptive repair function can effectively extend the service life of the material. Comparative Example 3 lacks such a repair mechanism, and the worn areas are exposed, leading to crack propagation and ultimately large-area material loss. From the data, the wear rate in the first 2000 revolutions is particularly obvious, indicating that the material loses wear protection at the initial stage.

[0105] The comparison of the microstructures also reveals the essential differences between the two. SEM shows that the worn area of Example 3 is relatively uniform and the damaged edge is smooth, indicating that the molecular chain segments inside the material can be effectively adjusted under stress. In Comparative Example 3, there are obvious spalling phenomena in the worn area and the crack propagation direction is disordered, suggesting that the internal connection ability of the material is poor. The wear resistance of the material is not determined by a single factor, but is the result of the combined action of filler distribution, repair ability and stress buffering mechanism.

[0106] Experiment 4: Interface Bonding Strength Test Experimental Procedures Specimen Preparation Select the specimens of Example 4 and Comparative Example 4, and cut them into test pieces of 25 mm × 25 mm to ensure consistent dimensions.

[0107] Coat the surface of the test piece with an epoxy adhesive with a thickness of 20 μm, bond it to the glass substrate, and keep it for 30 min to allow the adhesive layer to fully bond.

[0108] Surface Treatment The specimen of Example 4 is treated by plasma surface treatment with a power of 50 W and a treatment time of 3 min to improve the surface activity.

[0109] Comparative Example 4 only uses mechanical polishing and does not undergo plasma treatment.

[0110] Shear Strength Test Use an electronic tensile testing machine (Instron5967), set the loading rate at 1 mm / min, and measure the maximum shear force.

[0111] Record the fracture mode and observe the damage condition of the bonding interface.

[0112] Data Analysis Calculate the shear strength and use a scanning electron microscope (SEM) to analyze the cross-section bonding condition.

[0113] Experimental Data Table 4: Comparison of Shear Strengths of Different Specimens Experimental Summary The improvement of the interface bonding strength is not as simple as just increasing the surface roughness, but more involves the molecular-level interactions. The shear strength of Example 4 is much higher than that of Comparative Example 4, indicating that the activation effect of plasma treatment is significant. The plasma can remove the low-energy contaminants on the surface, making it easier for the epoxy adhesive to form chemical bonds with the substrate. Although Comparative Example 4 has undergone mechanical polishing, the bonding at the interface is still weak. The existence of micro-defects makes it easy to form stress concentration points inside the adhesive layer, leading to premature interface failure.

[0114] Not only is there a significant difference in the bonding strength, but also in the fracture mode. For the specimens of Example 4, fractures mostly occur within the adhesive layer rather than at the interface, indicating that the bonding interface strength exceeds the load-bearing capacity of the adhesive layer itself. In Comparative Example 4, the interface peeling phenomenon is more obvious, suggesting that the adhesive layer fails to effectively form a strong connection with the substrate. This phenomenon is particularly evident in the SEM images, where there are many unbonded areas on the surface without plasma treatment, forming gaps and thus reducing the bonding performance.

[0115] This improvement in the bonding force is closely related to the long-term stability of the material. The surface after plasma treatment not only increases the initial bonding force but also enhances the durability. Under the action of environmental stress, the bonding cross-section of Example 4 remains intact, while the adhesive layer of Comparative Example 4 is prone to failure under a lower load. The essence of the bonding force is not only physical contact but also a molecular-level synergistic effect.

[0116] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A production process for a double-opening middle armrest covering piece, characterized in that, Including: Preparation of a dynamic covalent cross-linked matrix. Through a high-temperature blending reaction, 50 - 60 parts of a polyurethane-polyurea copolymer are mixed with 10 - 15 parts of a double-dynamic thiol-ene cross-linking agent, and continuous stirring is carried out to form a dynamic cross-linked network; Dispersion of nano-fillers. 3 - 7 parts of silica nanoparticles are added to the blending system, and a high-shear dispersing machine is used for stirring to make them evenly dispersed; Synthesis of micro-scale self-healing liquid capsules. By using the double-emulsion polymerization method, 10 - 15 parts of polydimethylsiloxane are used as the core, and 3 - 5 parts of ultraviolet-curable epoxy resin are used as the shell, and pre-curing is carried out under ultraviolet light irradiation to form the healing liquid capsules; Preparation of macro-scale reversible deformation materials. Through high-temperature casting, 5 - 10 parts of a shape memory polymer are compounded with 2 - 4 parts of magnetic nanoparticles; Composite material forming process, including: Compression molding; Plasma surface treatment; Ultraviolet curing; Magnetic field-induced repair.

2. The production process of a double-opening middle armrest covering part according to claim 1, characterized in that The preparation of the dynamic covalent cross-linked matrix adopts a high-temperature blending reaction under the condition of 180 - 200 °C, and the continuous stirring time is 3 - 5 h. The polyurethane-polyurea copolymer is prepared by the reaction of isocyanate and polyether polyol. The double-dynamic thiol-ene cross-linking agent is a thiol-functional group modified polymer.

3. The production process of a double-opening middle armrest covering part according to claim 1, characterized in that The nano-filler dispersion process is treated with a high-shear dispersing machine, the stirring speed is 5000 - 8000 rpm, and the stirring time is 30 - 45 min.

4. A production process for a double-opening middle armrest covering member according to claim 1, characterized in that The synthesis of the micro-scale self-healing liquid capsules adopts the double-emulsion polymerization method, and curing is carried out under the condition of an ultraviolet curing wavelength of 365 - 405 nm, and the curing time is 10 - 20 min. The polydimethylsiloxane is a hydroxyl-terminated polydimethylsiloxane. The ultraviolet-curable epoxy resin is prepared by mixing bisphenol A epoxy resin and a photoinitiator.

5. A production process for a double-opening middle armrest covering part according to claim 1, characterized in that, The preparation of the macro-scale reversible deformation materials adopts high-temperature casting forming, the temperature range is 150 - 180 °C, and the casting time is 5 - 10 min. The shape memory polymer is a polylactic acid or a polyurethane-based shape memory material. The magnetic nanoparticles are magnetite nanoparticles.

6. The production process of a double-opening middle armrest covering part according to claim 1, characterized in that, The temperature range of the compression molding is 120 - 180 °C, the pressure range is 5 - 15 MPa, and the molding time is 30 - 60 min. During the compression molding process, curing is carried out by heating and pressurizing.

7. A production process for a double-opening middle armrest covering according to claim 1, characterized in that, The power of the plasma surface treatment is 50 - 100 W, the frequency is 20 - 40 kHz, and the treatment gas is oxygen or nitrogen.

8. A production process for a double-opening middle armrest covering member according to claim 1, characterized in that, The wavelength of the ultraviolet light curing is 365 - 405 nm, and the time is 10 - 20 min. The light curing device adopts an LED light source.

9. The production process of a double-opening middle armrest covering part according to claim 1, characterized in that, The magnetic field-induced repair is carried out with a magnetic induction intensity of 80 - 150 mT, and the magnetic field is provided by a permanent magnet or an electromagnetic coil.

10. The production process of a double-opening middle armrest covering part according to claim 1, characterized in that, The mass ratio of the dynamic covalent cross-linked matrix to the micro-scale liquid capsule self-healing layer is 4:1 - 6:1.

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