Photo-thermal response self-repairing type rubber sealing ring and preparation method and application thereof

Abstract

The invention discloses a photo-thermal response self-repairing type rubber sealing ring and a preparation method and application thereof, and belongs to the technical field of rubber products. The sealing ring comprises the following raw materials in parts by weight: 100 parts of a rubber base material, 5-20 parts of a double-wall microcapsule, 50-65 parts of a reinforcing component, 5-10 parts of a catalytic component, 2.5-3.5 parts of a vulcanizing agent, 2-3 parts of a cross-linking agent, 5-10 parts of a plasticizer, 1-2 parts of an antioxidant and 1-1.5 parts of an anti-aging agent, according to the photo-thermal response self-repairing type rubber sealing ring, the double-wall microcapsules and the catalytic component are introduced into the raw materials of the sealing ring, and a three-in-one mechanism of photo-thermal triggering, releasing and polymerization repairing is achieved, so that the photo-thermal response self-repairing type rubber sealing ring can automatically repair internal damage caused by fatigue, abrasion or tiny puncture under the irradiation of external near-infrared light (NIR), and the service life of the sealing ring is prolonged. Therefore, the sealing performance is recovered, and the service life is obviously prolonged.

Description

Technical Field

[0001] This invention belongs to the field of rubber product technology, specifically relating to photothermal responsive self-healing rubber sealing rings, their preparation methods, and applications. Background Technology

[0002] Rubber sealing rings, as a key elastic sealing element, are an indispensable basic component in modern industry. They are mainly installed at the connections or moving gaps of components such as pipes, flanges, and shafts, utilizing the high elastic deformation of rubber to fill the gaps, thereby effectively preventing leakage of liquids, gases, and other media. Their functions extend beyond static sealing and leak prevention, extending to buffering and shock absorption, compensating for thermal expansion and contraction, and protecting interfaces. They are widely used in critical fields such as building water supply and drainage, HVAC, automotive manufacturing, aerospace, petrochemicals, and hydraulic and pneumatic systems.

[0003] However, rubber failure often stems from the initiation and propagation of micro-cracks. Once traditional rubber materials are damaged, their performance deteriorates irreversibly, requiring downtime for replacement, resulting in high maintenance costs and safety hazards.

[0004] Inspired by the self-healing phenomenon of biological damage, self-healing materials have become a cutting-edge research direction for extending the lifespan of polymer materials. Among them, exogenous self-healing systems based on microcapsules encapsulating liquid repair agents have been extensively studied and have shown potential in thermosetting resins (such as epoxy resins). The basic principle is that microcapsules containing repair agents are pre-embedded inside the material. When cracks occur, the mechanical force of crack propagation punctures the microcapsules, releasing the repair agent to the crack surface, where it is repaired through a pre-placed catalyst or a chemical reaction with the matrix. However, directly transferring this seemingly mature technology to rubber sealing material systems faces significant challenges: (1) Poor compatibility between repair agents and rubber: Most repair agents are difficult to be well compatible with rubber base materials, which can easily lead to the deterioration of the mechanical properties of the matrix; (2) Low repair efficiency: The high elasticity of rubber causes cracks to open and close repeatedly under stress, and its hydrophobic surface is not conducive to the flow, wetting and bonding of repair agents, resulting in low repair efficiency. (3) The triggering method is not applicable: Traditional self-healing relies on the crack to puncture the microcapsule itself. For tightly closed fatigue cracks, the triggering efficiency is low; and rubber is often in a dark, closed space, lacking effective external triggering energy.

[0005] Therefore, overcoming the compatibility problem between repair agents and highly cross-linked rubber base materials, and breaking through the limitations of passive triggering mechanisms on micro-fatigue cracks, developing a high-performance self-healing rubber seal ring is a problem that needs to be solved. Summary of the Invention

[0006] One of the objectives of this invention is to provide a photothermal responsive self-healing rubber sealing ring, which overcomes the current problem of poor compatibility between repair agents and rubber base materials, and breaks through the limitations of passive triggering mechanisms for micro-fatigue cracks. The resulting sealing ring can automatically repair internal damage caused by fatigue, wear or micro-punctures under external near-infrared light (NIR) irradiation, thereby restoring its sealing performance and significantly extending its service life.

[0007] The second objective of this invention is to provide a method for preparing the above-mentioned photothermal responsive self-healing rubber seal.

[0008] The third objective of this invention is to provide the application of the above-mentioned photothermal responsive self-healing rubber seal.

[0009] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a photothermal responsive self-healing rubber sealing ring, comprising the following raw materials in parts by weight: 100 parts rubber base, 5-20 parts double-walled microcapsules, 50-65 parts reinforcing components, 5-10 parts catalytic components, 2.5-3.5 parts vulcanizing agent, 2-3 parts crosslinking agent, 5-10 parts plasticizer, 1-2 parts antioxidant, and 1-1.5 parts antioxidant.

[0010] Preferably, the double-walled microcapsules have a particle size of 150-200 μm. These double-walled microcapsules are the core components for realizing photothermal triggered self-healing functions. They adopt a special "core-shell-shell" three-layer structure design to achieve efficient encapsulation, stable storage, and controllable release of the repair agent.

[0011] Preferably, the double-walled microcapsule comprises a core, an inner wall, and an outer wall from the inside out. The core is dicyclopentadiene, the inner wall is urea-formaldehyde resin, and the outer wall is polyurea or polyurethane. The outer wall carries photothermal conversion nanoparticles.

[0012] The selected core material, dicyclopentadiene (DCPD), is a low-melting-point, highly reactive diene monomer. It is liquid at the applicable temperature and possesses low viscosity, which facilitates rapid flow and filling of microcracks after triggering. More importantly, DCPD can rapidly solidify via ring-opening metathesis polymerization (ROMP), a reaction characterized by minimal volume shrinkage, reducing internal stress during the repair process. Simultaneously, its polymerization products exhibit a certain degree of polarity compatibility with the rubber base material, promoting the formation of a strong bond at the crack interface, thereby efficiently restoring the mechanical and sealing properties of the sealing material.

[0013] The selected inner bladder wall thickness is 0.5-1 μm. The main function of the inner wall material is to provide a reliable sealing environment for the DCPD, preventing it from penetrating or failing during rubber mixing and storage. Its wall thickness is preferably controlled between 0.5 μm and 1 μm. This thickness range ensures sufficient mechanical strength to resist processing shear forces while also ensuring that it can be effectively melted through during photothermal triggering.

[0014] The photothermal conversion nanoparticles are at least one of carbon nanotubes, graphene, graphene oxide, and MXene. The outer capsule wall provides additional toughness protection for the microcapsule, buffers external mechanical stress, and serves as a carrier for the photothermal response function. The photothermal conversion nanoparticles dispersed therein have strong absorption characteristics in the near-infrared light band, enabling them to efficiently convert light energy into heat energy.

[0015] Preferably, the preparation of the double-walled microcapsules is carried out in two steps, as follows: S1. Mix urea and formaldehyde solution evenly and adjust the pH to 7-8 with triethanolamine aqueous solution. Treat at 70℃ for 1h to obtain urea-formaldehyde resin prepolymer. Add dicyclopentadiene to ethylene-maleic anhydride copolymer aqueous solution and stir at 300-500r / min for 1-1.5h to obtain DCPD emulsion. Add urea-formaldehyde resin prepolymer to DCPD emulsion, adjust the pH of the system to 3.5-4 with hydrochloric acid solution, and react at 55-65℃ for 3-5h. After the reaction is completed, filter, wash the filter cake with anhydrous ethanol and dry to obtain single-walled microcapsules. S2. Disperse single-walled microcapsules in acetone, then add an aqueous dispersion of photothermal conversion nanoparticles. After stirring until homogeneous, add diisocyanate dropwise, followed by chain extender. Stir and react at room temperature for 3-5 hours, then raise the temperature to 40-50℃ and continue the reaction for 1-2 hours. After the reaction is complete, filter, wash and dry the filter cake to obtain double-walled microcapsules. As a preferred embodiment, the ratio of urea, formaldehyde solution, dicyclopentadiene, and ethylene-maleic anhydride copolymer aqueous solution in S1 is 7.4g:18-19mL:20-35g:150-250mL, the mass fraction of triethanolamine aqueous solution is 8-10%, the mass fraction of ethylene-maleic anhydride copolymer aqueous solution is 1-2%, and the mass fraction of hydrochloric acid solution is 1-3%.

[0016] Preferably, the formaldehyde solution has a mass fraction of 37-40%.

[0017] As a preferred embodiment, the ratio of single-walled microcapsules, acetone, photothermal conversion nanoparticles, diisocyanate and chain extender in S2 is 10g:100mL:0.5-1.5g:1-2g:0.43-0.86g.

[0018] Preferably, the diisocyanate is at least one of toluene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

[0019] Preferably, the chain extender is an amine compound and / or an alcohol compound, wherein the amine compound is at least one selected from ethylenediamine, diethylenetriamine, and hexamethylenediamine, and the alcohol compound is at least one selected from ethylene glycol, 1,4-butanediol, and 1,6-hexanediol.

[0020] Preferably, the photothermal conversion nanoparticle aqueous dispersion is prepared by mixing photothermal conversion nanoparticles, emulsifier and deionized water in a ratio of 1g:0.1-0.5g:20-50mL.

[0021] Preferably, the emulsifier is sodium dodecylbenzenesulfonate (SDBS) and / or polyethylene glycol octylphenyl ether (Triton X-100).

[0022] Preferably, the catalytic component is ruthenium dichloride supported on benzenemethylene bis(tricyclohexylphosphine)dichloride in porous nano-silica.

[0023] Preferably, the catalytic component is prepared using the following steps: Add benzenemethylenebis(tricyclohexylphosphine) ruthenium dichloride to dichloromethane and stir until homogeneous. Then add porous nano-silica and stir for 4-6 hours under light-protected and argon-protected conditions. Finally, remove dichloromethane by rotary evaporation to obtain the catalytic component.

[0024] As a preferred embodiment, the mass ratio of benzenemethylbis(tricyclohexylphosphine) ruthenium dichloride to porous nano-silica is 1:3-5.

[0025] Preferably, the porous nano-silica has a specific surface area of ​​not less than 250 m². 2 / g, with an average pore size of 2-20nm. If the average pore size of porous nano silica is too small, the catalyst molecules cannot enter the pores smoothly and are only loaded on the surface, which is easy to deactivate; if the pore size is too large, the immobilization effect is not good and the catalyst may fall off in the subsequent rubber compounding.

[0026] Preferably, the rubber base material is at least one of hydrogenated nitrile rubber, ethylene propylene diene monomer (EPDM) rubber, and fluororubber.

[0027] Preferably, the reinforcing component is composed of carbon black N550 and fumed silica, with a mass ratio of carbon black N550 to fumed silica of 4-5:1-1.5.

[0028] Preferably, the plasticizer is at least one of dioctyl sebacate, dioctyl adipate, and di(butoxyethoxyethyl) adipate.

[0029] Preferably, the vulcanizing agent is dicumyl peroxide and / or 1,4-di-tert-butylperoxide.

[0030] Preferably, the crosslinking agent is triallyl isocyanurate.

[0031] Preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 1076 and antioxidant 168.

[0032] Preferably, the antioxidant is at least one of 2,2,4-trimethyl-1,2-dihydroquinoline polymer (antioxidant RD), 2-thiol-benzoimidazole (antioxidant MB), and N-isopropyl-N'-phenyl-p-phenylenediamine (antioxidant 4010NA).

[0033] The self-healing rubber sealing ring provided by this invention utilizes a three-pronged repair mechanism: photothermal triggering, release, and polymerization repair. This system consists of double-walled microcapsules embedded in a rubber matrix and a supported latent catalyst. When microscopic damage occurs within the material due to fatigue or other reasons, the damaged area is irradiated with external near-infrared light (NIR). The photothermal conversion nanoparticles (such as multi-walled carbon nanotubes) on the outer layer of the microcapsules efficiently convert light energy into heat energy. This heat locally softens the rubber matrix at the crack tip, reducing its modulus to facilitate the wetting of the repair agent; simultaneously, it precisely melts the microcapsule wall, releasing the encapsulated repair agent, dicyclopentadiene, as needed and at specific points. The released repair agent rapidly penetrates the crack and comes into contact with the supported Grubbs catalyst pre-dispersed in the matrix, initiating a rapid, low-volume shrinkage ring-opening metathesis polymerization reaction. The resulting polydicyclopentadiene forms an effective filler, filling and bridging the crack. In addition, the active ends of the polydicyclopentadiene may also interpenetrate or combine with the surrounding thermally activated rubber molecular chains through free radicals or physical entanglement, thereby achieving mechanical bridging and effective sealing of the crack.

[0034] Secondly, the present invention provides a method for preparing a photothermal responsive self-healing rubber sealing ring, comprising the following steps: Step 1: Add rubber base material, reinforcing components, crosslinking agent, plasticizer, antioxidant, and anti-aging agent to a two-roll mill and mix at 60-75℃ for 8-12 minutes to obtain masterbatch. Then add catalytic components to the masterbatch and mix at 45℃ with a roll gap of 0.5-1.0mm for 3-5 minutes. Next, add double-walled microcapsules and mix at a roll gap of 1.5-2.0mm for 3-5 minutes to obtain compound. The second step is to add a vulcanizing agent to the rubber compound, mix at 35-45℃ for 3-5 minutes, and finally vulcanize to obtain a photothermal responsive self-healing rubber sealing ring.

[0035] Preferably, the vulcanization temperature is 160-180℃, the vulcanization pressure is 10-20MPa, and the vulcanization time is 10-20min.

[0036] Preferably, the open mill speed is 25-35 r / min.

[0037] This invention employs a two-stage low-temperature mixing strategy to achieve uniform dispersion of catalytic components and double-walled microcapsules while ensuring their structural integrity and chemical activity. This is the key process guarantee for the realization of this self-healing technology.

[0038] Thirdly, the present invention provides the application of the photothermal responsive self-healing rubber sealing ring in dynamic or static sealing systems.

[0039] This invention is particularly suitable for sealing components that are difficult or impossible to maintain regularly due to concealed installation locations, inconvenient disassembly and assembly, or stringent requirements for long-term operational reliability. Its non-contact, point-triggered repair characteristics provide a revolutionary long-life solution for these scenarios.

[0040] Non-limiting examples of the applications are as follows: pre-embedded pipe sealing joints in buildings, valve core seals for smart bathroom equipment, seals for high-end hydraulic and pneumatic actuators, sealing systems for aerospace vehicles, seals for electric drive and battery systems in new energy vehicles, and rotary shaft seals and flange face seals in various industrial equipment that require maintenance-free or extremely high reliability.

[0041] The beneficial effects of this invention are: 1. The photothermal responsive self-healing rubber sealing ring provided by the present invention can automatically repair internal damage caused by fatigue, wear or micro-punctures under external near-infrared light (NIR) irradiation, thereby restoring its sealing performance and significantly extending its service life.

[0042] 2. This invention introduces near-infrared light as external trigger energy, enabling non-contact remote control. Its "photothermal triggering" mechanism has a high degree of spatial and temporal controllability: the repair agent is released only when the damaged area is irradiated, avoiding unnecessary consumption; at the same time, the release amount and repair range of the repair agent can be precisely controlled by adjusting the light parameters (such as power and time).

[0043] 3. The catalyst of this invention is supported by porous nano-silica, which not only achieves uniform dispersion and physical isolation in rubber to prevent premature deactivation, but also ensures effective exposure to the crack surface during repair.

[0044] 4. Through specific formulation and process design, this invention introduces self-healing function while maximizing the maintenance of the matrix performance of the sealing ring. The outer polyurethane / carbon nanotube structure of the double-walled microcapsule provides good toughness, allowing it to remain intact during rubber mixing and vulcanization. Detailed Implementation

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] The following examples illustrate the specific details. In the examples and comparative examples below, the ethylene-maleic anhydride copolymer (EMA), also known as poly(ethylene-alt-maleic anhydride), with an average Mw of 100,000, was purchased from Sigma Aldrich, USA; the porous nano-silica was commercially available mesoporous silica nanospheres with a specific surface area of ​​410-680 m2 / g and a pore size of 2.8-13.3 nm, and hydrogenated nitrile butadiene rubber (HNBR, hydrogenation degree 90%).

[0047] Preparation Example 1

[0048] A double-walled microcapsule, the specific steps of which are as follows: S1. Mix 7.4g of urea and 18mL of 37wt% formaldehyde solution evenly and adjust the pH to 7 with 8wt% triethanolamine aqueous solution. Treat at 70℃ for 1h to obtain urea-formaldehyde resin prepolymer. Add 20g of dicyclopentadiene to 150mL of ethylene-maleic anhydride copolymer aqueous solution with a mass fraction of 1%. Stir at 300r / min for 1h to obtain DCPD emulsion. Add urea-formaldehyde resin prepolymer to DCPD emulsion. Adjust the pH of the system to 3.5 with 1wt% hydrochloric acid solution. Heat to 55℃ and react for 3h. After the reaction is completed, filter. Wash the filter cake with anhydrous ethanol and dry to obtain single-walled microcapsules. S2. Disperse 10g of single-walled microcapsules in 100mL of acetone, then add an aqueous dispersion of photothermal conversion nanoparticles. The aqueous dispersion of photothermal conversion nanoparticles is composed of 0.5g of carbon nanotubes, 0.25g of sodium dodecylbenzenesulfonate, and 50mL of deionized water. After stirring evenly, add 1g of toluene diisocyanate dropwise, followed by 0.43g of ethylenediamine. Stir the reaction at room temperature for 3h, then raise the temperature to 40℃ and continue the reaction for 1h. After the reaction is completed, filter the mixture, wash the filter cake, and dry it to obtain double-walled microcapsules.

[0049] Preparation Example 2

[0050] A double-walled microcapsule, the specific steps of which are as follows: S1. Mix 7.4g of urea and 18.5mL of 37wt% formaldehyde solution evenly and adjust the pH to 7 with 9wt% triethanolamine aqueous solution. Treat at 70℃ for 1h to obtain urea-formaldehyde resin prepolymer. Add 30g of dicyclopentadiene to 200mL of ethylene-maleic anhydride copolymer aqueous solution with a mass fraction of 1.5%. Stir at 400r / min for 1.3h to obtain DCPD emulsion. Add urea-formaldehyde resin prepolymer to DCPD emulsion. Adjust the pH of the system to 3.5 with 2wt% hydrochloric acid solution. Heat to 60℃ and react for 4h. After the reaction is completed, filter. Wash the filter cake with anhydrous ethanol and dry to obtain single-walled microcapsules. S2. Disperse 10g of single-walled microcapsules in 100mL of acetone, then add an aqueous dispersion of photothermal conversion nanoparticles, which is composed of 1.0g of carbon nanotubes, 0.5g of sodium dodecylbenzenesulfonate and 65mL of deionized water. After stirring evenly, add 1.5g of toluene diisocyanate dropwise, followed by 0.65g of diethylenetriamine. Stir the mixture at room temperature for 4h, then raise the temperature to 45℃ and continue the reaction for 1.5h. After the reaction is complete, filter the mixture, wash the filter cake and dry it to obtain double-walled microcapsules.

[0051] Preparation Example 3

[0052] A double-walled microcapsule, the specific steps of which are as follows: S1. Mix 7.4g of urea and 19mL of 37wt% formaldehyde solution evenly and adjust the pH to 8 with 10wt% triethanolamine aqueous solution. Treat at 70℃ for 1h to obtain urea-formaldehyde resin prepolymer. Add 35g of dicyclopentadiene to 250mL of ethylene-maleic anhydride copolymer aqueous solution with a mass fraction of 2%. Stir at 500r / min for 1.5h to obtain DCPD emulsion. Add urea-formaldehyde resin prepolymer to DCPD emulsion. Adjust the pH of the system to 4 with 3wt% hydrochloric acid solution. Heat to 65℃ and react for 5h. After the reaction is completed, filter. Wash the filter cake with anhydrous ethanol and dry to obtain single-walled microcapsules. S2. Disperse 10g of single-walled microcapsules in 100mL of acetone, then add an aqueous dispersion of photothermal conversion nanoparticles, which is composed of 1.5g of carbon nanotubes, 0.75g of sodium dodecylbenzenesulfonate and 75mL of deionized water. After stirring evenly, add 2g of toluene diisocyanate dropwise, followed by 0.86g of hexamethylenediamine. Stir the reaction at room temperature for 5h, then raise the temperature to 50℃ and continue the reaction for 2h. After the reaction is completed, filter, wash the filter cake and dry it to obtain double-walled microcapsules.

[0053] Compare with Example 1

[0054] A double-walled microcapsule, which differs from Preparation Example 1 only in that the "photothermal conversion nanoparticle aqueous dispersion" in Preparation Example 1 is removed.

[0055] Compare with Example 2

[0056] A microcapsule, the specific steps of which are as follows: S1. Mix 7.4g of urea and 18g of 37wt% formaldehyde solution evenly and adjust the pH to 7 with 8wt% triethanolamine aqueous solution. Treat at 70℃ for 1h to obtain urea-formaldehyde resin prepolymer. Add 20g of dicyclopentadiene to 150mL of ethylene-maleic anhydride copolymer aqueous solution with a mass fraction of 1%. Stir at 300r / min for 1h to obtain DCPD emulsion. Add the urea-formaldehyde resin prepolymer and photothermal conversion nanoparticle aqueous dispersion to the DCPD emulsion. The photothermal conversion nanoparticle aqueous dispersion is composed of 0.5g of carbon nanotubes, 0.25g of sodium dodecylbenzenesulfonate and 50mL of deionized water. Adjust the pH of the system to 3.5 with 1wt% hydrochloric acid solution. Heat to 55℃ and react for 3h. After the reaction is completed, filter. Wash the filter cake with anhydrous ethanol and dry to obtain single-walled microcapsules. Compare with Example 3 A double-walled microcapsule, compared with preparation example 1, differs only in that step S2 is omitted.

[0057] Example 1

[0058] Photothermal responsive self-healing rubber seal ring, comprising the following parts by weight of raw materials: 100 parts of hydrogenated nitrile rubber, 5 parts of double-walled microcapsules of Preparation Example 1, 50 parts of reinforcing component, 5 parts of catalytic component, 2.5 parts of dicumyl peroxide, 2 parts of triallyl isocyanurate, 5 parts of dioctyl sebacate, 1 part of antioxidant 1010, and 1 part of antioxidant RD.

[0059] The specific steps for the catalytic component are as follows: 1g of benzenemethylene bis(tricyclohexylphosphine) ruthenium dichloride was added to 50mL of dichloromethane and stirred until homogeneous. Then, 3g of porous nano-silica was added. The mixture was stirred and mixed for 4 hours under light-protected and argon-protected conditions. Finally, the dichloromethane was removed by rotary evaporation to obtain the catalytic component.

[0060] The reinforcing component consists of carbon black N550 and fumed silica, with a mass ratio of carbon black N550 to fumed silica of 4:1.

[0061] The preparation method of the above-mentioned photothermal responsive self-healing rubber seal includes the following steps: Step 1: Add rubber base material, reinforcing components, triallyl isocyanurate, dioctyl sebacate, antioxidant 1010, and antioxidant RD to a two-roll mill. Mix the two-roll mill at 25 r / min and 60°C for 8 min to obtain masterbatch. Then add catalytic components to the masterbatch and mix at 45°C and 0.5 mm roller gap for 3 min. Next, add double-walled microcapsules and mix at 1.5 mm roller gap for 3 min to obtain compound. The second step is to add dicumyl peroxide to the rubber compound, mix at 35°C for 3 minutes, and finally vulcanize and mold it. The vulcanization temperature is 160°C, the vulcanization pressure is 10MPa, and the vulcanization time is 10 minutes to obtain a photothermal responsive self-healing rubber sealing ring.

[0062] Example 2

[0063] Photothermal responsive self-healing rubber seal ring, comprising the following parts by weight of raw materials: 100 parts of hydrogenated nitrile rubber, 10 parts of double-walled microcapsules of Preparation Example 1, 55 parts of reinforcing component, 8 parts of catalytic component, 3.0 parts of dicumyl peroxide, 2.5 parts of triallyl isocyanurate, 8 parts of dioctyl sebacate, 1.5 parts of antioxidant 1010, and 1 part of antioxidant RD.

[0064] The specific steps of the catalytic component are the same as in Example 1. The reinforcing component consists of carbon black N550 and fumed silica, with a mass ratio of carbon black N550 to fumed silica of 4:1.

[0065] The preparation method of the above-mentioned photothermal responsive self-healing rubber seal includes the following steps: Step 1: Add rubber base material, reinforcing components, triallyl isocyanurate, dioctyl sebacate, antioxidant 1010, and antioxidant RD to a two-roll mill. Mix at 30 r / min and 70°C for 10 min to obtain masterbatch. Then add catalytic components to the masterbatch and mix at 45°C and 0.8 mm roller gap for 4 min. Next, add double-walled microcapsules and mix at 1.5 mm roller gap for 4 min to obtain compound. The second step is to add dicumyl peroxide to the rubber compound, mix at 40°C for 4 minutes, and finally vulcanize and mold it. The vulcanization temperature is 170°C, the vulcanization pressure is 15MPa, and the vulcanization time is 15 minutes to obtain a photothermal responsive self-healing rubber sealing ring.

[0066] Example 3

[0067] Photothermal responsive self-healing rubber seal ring, comprising the following parts by weight of raw materials: 100 parts of hydrogenated nitrile rubber, 20 parts of double-walled microcapsules of Preparation Example 1, 65 parts of reinforcing component, 10 parts of catalytic component, 3.5 parts of dicumyl peroxide, 3 parts of triallyl isocyanurate, 10 parts of dioctyl sebacate, 2 parts of antioxidant 1010, and 1.5 parts of antioxidant RD.

[0068] The specific steps of the catalytic component are the same as in Example 1. The reinforcing component consists of carbon black N550 and fumed silica, with a mass ratio of carbon black N550 to fumed silica of 5:1.5.

[0069] The preparation method of the above-mentioned photothermal responsive self-healing rubber seal includes the following steps: Step 1: Add rubber base material, reinforcing components, triallyl isocyanurate, dioctyl sebacate, antioxidant 1010, and antioxidant RD to a two-roll mill. Mix the two-roll mill at 35 r / min and 75°C for 12 min to obtain masterbatch. Then add catalytic components to the masterbatch and mix at 45°C and 1.0 mm roller gap for 5 min. Next, add double-walled microcapsules and mix at 2.0 mm roller gap for 5 min to obtain compound. The second step is to add dicumyl peroxide to the rubber compound, mix at 45°C for 5 minutes, and finally vulcanize and mold it. The vulcanization temperature is 180°C, the vulcanization pressure is 20MPa, and the vulcanization time is 20 minutes to obtain a photothermal responsive self-healing rubber sealing ring.

[0070] Example 4

[0071] The photothermal responsive self-healing rubber sealing ring differs from Example 1 only in that the specific steps for the catalytic component in this example are as follows: 1g of benzenemethylene bis(tricyclohexylphosphine) ruthenium dichloride was added to 50mL of dichloromethane and stirred until homogeneous. Then, 4g of porous nano-silica was added. The mixture was stirred and mixed for 5h under light-protected and argon-protected conditions. Finally, the dichloromethane was removed by rotary evaporation to obtain the catalytic component.

[0072] Example 5

[0073] The photothermal responsive self-healing rubber sealing ring differs from Example 1 only in that the specific steps for the catalytic component in this example are as follows: 1g of benzenemethylene bis(tricyclohexylphosphine) ruthenium dichloride was added to 50mL of dichloromethane and stirred until homogeneous. Then, 5g of porous nano-silica was added. The mixture was stirred and mixed for 6 hours under light-protected and argon-protected conditions. Finally, the dichloromethane was removed by rotary evaporation to obtain the catalytic component.

[0074] Example 6

[0075] The photothermal responsive self-healing rubber sealing ring differs from Example 1 only in that the double-walled microcapsules in Example 1 are replaced with an equal weight of the product obtained in Preparation Example 2.

[0076] Example 7

[0077] The photothermal responsive self-healing rubber sealing ring differs from Example 1 only in that the double-walled microcapsules in Example 1 are replaced with an equal weight of the product obtained in Preparation Example 3.

[0078] Example 8

[0079] The photothermal responsive self-healing rubber sealing ring differs from Example 2 only in that the double-walled microcapsules in Example 2 are replaced with an equal weight of the product obtained in Preparation Example 3.

[0080] Comparative Example 1

[0081] The photothermal responsive self-healing rubber sealing ring differs from Example 1 only in that the double-walled microcapsules in Example 1 are replaced with an equal weight of the product obtained in Comparative Example 1.

[0082] Comparative Example 2

[0083] The photothermal responsive self-healing rubber sealing ring differs from Example 1 only in that the double-walled microcapsules in Example 1 are replaced with an equal weight of the product obtained in Comparative Example 2.

[0084] Comparative Example 3

[0085] The photothermal responsive self-healing rubber sealing ring differs from Example 1 only in that the double-walled microcapsules in Example 1 are replaced with an equal weight of the product obtained in Comparative Example 3.

[0086] Comparative Example 4

[0087] The photothermal responsive self-healing rubber sealing ring differs from Example 1 only in that the catalytic component in Example 1 is replaced with an equal mass of "benzyl bis(tricyclohexylphosphine) ruthenium dichloride and porous nano silica mixed in a mass ratio of 1:3 in a mixer at 200 r / min for 20 min".

[0088] Comparative Example 5

[0089] The photothermal responsive self-healing rubber sealing ring differs from Example 1 only in that the catalytic component in Example 1 is replaced with an equal mass of benzenemethylene bis(tricyclohexylphosphine) ruthenium dichloride.

[0090] Comparative Example 6

[0091] The photothermal responsive self-healing rubber seal ring differs from Example 1 only in that the catalytic component in Example 1 is removed.

[0092] Comparative Example 7

[0093] The photothermal responsive self-healing rubber sealing ring differs from Example 1 only in that the double-walled microcapsules in Example 1 are replaced with an equal weight of the product obtained in Comparative Example 2, and the catalytic component is removed.

[0094] The rubber sealing rings obtained in Examples 1-8 and Comparative Examples 1-7 were tested, and the test process is as follows: Tensile strength: The Instron 68TM-10 electronic universal testing machine was used, and the test was conducted at 25°C with a tensile rate of 500 mm / min, in accordance with ISO 37-2025 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The original gauge length of the sample was 25 mm, and each test was repeated 5 times. Self-healing efficiency: Artificial cuts 100 μm wide and 2 mm deep were fabricated on the test samples, and the self-healing efficiency was tested at a power density of 1.5 W / cm². 2 Irradiate with an 808nm laser for 60s, and test the tensile strength again according to the above tensile strength test method. Calculate the self-healing efficiency: Self-healing efficiency = (Tensile strength after repair / Original tensile strength) × 100%. The results are shown in Table 1: Table 1

[0095] Analysis of the data recorded in Table 1 shows that the tensile strength of the sealing rings described in Examples 1-8 is 25.5-28.6 MPa, and the self-healing efficiency is ≥89%, reaching a maximum of 100%. This indicates that the technical path provided by the present invention, which is "near-infrared light triggers the release of DCPD from double-walled microcapsules and the self-healing is achieved by rapid polymerization initiated by a supported catalyst", is highly feasible and efficient.

[0096] As shown in Table 1, the complete technical solution provided by this invention (Example 1) achieves a self-repair efficiency of up to 89.4%. In contrast, if only the photothermal conversion nanoparticles are removed (Comparative Example 1) or only a single-wall structure is used (Comparative Example 3), the self-repair efficiency drops drastically, proving that both photothermal conversion nanoparticles and double-wall structures are indispensable for achieving efficient and controllable photo-triggered repair. More importantly, even when seemingly similar components are used (such as placing CNTs in the inner wall material, Comparative Example 2; or using unsupported catalysts, Comparative Examples 4 and 5), the repair efficiency is far lower than that of this invention. This fully demonstrates that the specific structure and combination of "photothermal nanoparticles distributed on the outer layer of double-walled microcapsules" and "catalyst supported on a porous carrier" in this invention produces a significant synergistic effect, achieving unexpected technical results.

[0097] Specifically, in Comparative Example 1, lacking a photothermal conversion unit, near-infrared light could not effectively trigger capsule rupture to release the repair agent, resulting in a significant decrease in self-repair capability and slightly lower strength due to the presence of microcapsules as inert fillers. Comparative Example 2 used single-walled microcapsules, which had poor strength, leading to a decrease in the tensile strength of the sealing ring. Comparative Example 3 used microcapsules without a double-walled structure; the single-walled capsules were prone to rupture during the mixing and vulcanization process, resulting in premature loss or deactivation of the repair agent, and the lack of a photothermal triggering layer rendered the repair function essentially ineffective.

[0098] In Comparative Examples 4 and 5, the catalysts were not effectively loaded, and the catalysts were prone to agglomeration and deactivation, which may interfere with cross-linking, resulting in a decrease in strength and a significant reduction in self-healing effect.

[0099] Comparative Example 6 lacks catalytic components, so the repair agent cannot polymerize and relies solely on viscous physical filling, resulting in low repair strength. Comparative Example 7 lacks both catalytic components and uses single-walled microcapsules, creating a dual failure scenario of "low triggering efficiency" and "lack of repair reaction," leading to poor overall performance of the sealing ring.

[0100] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0101] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A photothermal responsive self-healing rubber sealing ring, characterized in that, Including the following parts by weight of raw materials: 100 parts rubber base material, 5-20 parts double-walled microcapsules, 50-65 parts reinforcing components, 5-10 parts catalytic components, 2.5-3.5 parts vulcanizing agent, 2-3 parts crosslinking agent, 5-10 parts plasticizer, 1-2 parts antioxidant, and 1-1.5 parts antioxidant. The double-walled microcapsule comprises, from the inside out, a core, an inner wall, and an outer wall. The core is dicyclopentadiene, the inner wall is urea-formaldehyde resin, and the outer wall is polyurea or polyurethane. The outer wall carries photothermal conversion nanoparticles. The catalytic component is ruthenium dichloride supported on benzenemethylene bis(tricyclohexylphosphine) supported on porous nano-silica.

2. The photothermal responsive self-healing rubber sealing ring according to claim 1, characterized in that, The photothermal conversion nanoparticles are at least one of carbon nanotubes, graphene, graphene oxide, and MXene materials.

3. The photothermal responsive self-healing rubber sealing ring according to claim 1, characterized in that, The preparation of the double-walled microcapsules is carried out in two steps, as follows: S1. Mix urea and formaldehyde solution evenly and adjust the pH to 7-8 with triethanolamine aqueous solution. Treat at 70℃ for 1h to obtain urea-formaldehyde resin prepolymer. Add dicyclopentadiene to ethylene-maleic anhydride copolymer aqueous solution and stir at 300-500r / min for 1-1.5h to obtain DCPD emulsion. Add urea-formaldehyde resin prepolymer to DCPD emulsion, adjust the pH of the system to 3.5-4 with hydrochloric acid solution, and react at 55-65℃ for 3-5h. After the reaction is completed, filter, wash the filter cake with anhydrous ethanol and dry to obtain single-walled microcapsules. S2. Disperse single-walled microcapsules in acetone, add photothermal conversion nanoparticle aqueous dispersion, stir evenly, add diisocyanate dropwise, add chain extender, stir at room temperature for 3-5 hours, raise the temperature to 40-50℃, continue the reaction for 1-2 hours, after the reaction is completed, filter, wash the filter cake and dry it to obtain double-walled microcapsules.

4. The photothermal responsive self-healing rubber sealing ring according to claim 3, characterized in that, The ratio of urea, formaldehyde solution, dicyclopentadiene, and ethylene-maleic anhydride copolymer aqueous solution in S1 is 7.4g:18-19mL:20-35g:150-250mL. The mass fraction of triethanolamine aqueous solution is 8-10%, the mass fraction of ethylene-maleic anhydride copolymer aqueous solution is 1-2%, and the mass fraction of hydrochloric acid solution is 1-3%.

5. The photothermal responsive self-healing rubber sealing ring according to claim 3, characterized in that, The ratio of single-walled microcapsules, acetone, photothermal conversion nanoparticles, diisocyanate, and chain extender in S2 is 10g:100mL:0.5-1.5g:1-2g:0.43-0.86g.

6. The photothermal responsive self-healing rubber sealing ring according to claim 3, characterized in that, The chain extender is an amine compound and / or an alcohol compound, wherein the amine compound is at least one selected from ethylenediamine, diethylenetriamine, and hexamethylenediamine, and the alcohol compound is at least one selected from ethylene glycol, 1,4-butanediol, and 1,6-hexanediol.

7. The photothermal responsive self-healing rubber sealing ring according to claim 1, characterized in that, The specific steps for the catalytic component are as follows: Add benzenemethylenebis(tricyclohexylphosphine) ruthenium dichloride to dichloromethane and stir until homogeneous. Then add porous nano-silica and stir for 4-6 hours under light-protected and argon-protected conditions. Finally, remove dichloromethane by rotary evaporation to obtain the catalytic component.

8. The photothermal responsive self-healing rubber sealing ring according to claim 7, characterized in that, The mass ratio of benzenemethylbis(tricyclohexylphosphine)ruthenium dichloride to porous nano-silica is 1:3-5, and the specific surface area of ​​the porous nano-silica is not less than 250 m². 2 / g, with an average pore size of 2-20nm.

9. A method for preparing a photothermal responsive self-healing rubber sealing ring, characterized in that, The preparation of the photothermal responsive self-healing rubber sealing ring according to any one of claims 1-8 includes the following steps: Step 1: Add rubber base material, reinforcing components, crosslinking agent, plasticizer, antioxidant, and anti-aging agent to a two-roll mill and mix at 60-75℃ for 8-12 minutes to obtain masterbatch. Then add catalytic components to the masterbatch and mix at 45℃ with a roll gap of 0.5-1.0mm for 3-5 minutes. Next, add double-walled microcapsules and mix at a roll gap of 1.5-2.0mm for 3-5 minutes to obtain compound. The second step is to add a vulcanizing agent to the rubber compound, mix at 35-45℃ for 3-5 minutes, and finally vulcanize to obtain a photothermal responsive self-healing rubber sealing ring.

10. The application of the photothermal responsive self-healing rubber seal as described in any one of claims 1-8 in dynamic or static sealing systems.

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