Macromolecular self-repairing material for tire and preparation method of macromolecular self-repairing material

Abstract

The invention discloses a macromolecular self-repairing material for a tire and a preparation method of the macromolecular self-repairing material. Comprising 55 to 65 parts of polyurethane modified rubber, 25 to 30 parts of emulsion polymerized styrene-butadiene rubber, 6 to 10 parts of ethylene-acrylate rubber, 12 to 20 parts of composite resin, 10 to 13 parts of naphthenic rubber oil, 7 to 11 parts of hydroxyl-terminated polyisobutene, 25 to 41 parts of composite reinforcing filler, 10 to 15 parts of a composite plasticizer, 1.5 to 2.5 parts of a titanate coupling agent, 1 to 1.5 parts of a vulcanizing agent, 0.5 to 0.8 part of an assistant crosslinker, 0.4 to 0.7 part of a vulcanization accelerator and 1.5 to 2.5 parts of a vulcanization accelerator. The high-molecular self-repairing material for the tire can realize the self-repairing effect of the tire, has excellent durability and adhesive force, greatly improves the anti-puncture and anti-air-leakage functions of the tire, and improves the safety performance of a vehicle.

Description

Technical Field

[0001] This invention relates to a self-healing polymer material for tires and its preparation method, belonging to the field of polymer materials technology. Background Technology

[0002] Tires are ring-shaped, elastic rubber products fitted onto various vehicles for contact with the ground and rolling. They are key components in contact with the road surface, primarily supporting the vehicle body, cushioning vibrations, and transmitting driving and braking forces. When a tire runs over a sharp object, it is easily punctured, causing high-pressure gas to leak out. At high speeds, this can lead to tire blowouts or rapid leaks, potentially resulting in fatalities. Therefore, it is necessary to incorporate self-healing features into the tire's tread and sidewalls to improve puncture and leak prevention, thereby enhancing vehicle safety. Summary of the Invention

[0003] To address at least one problem existing in the prior art, the present invention provides a polymer self-healing material for tires and its preparation method. The material is coated on the inside of the tire crown and sidewall to form a coating, which enables the tire to self-heal. It has excellent durability and adhesion, greatly improves the tire's anti-puncture and anti-leakage functions, and enhances vehicle safety performance.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a self-healing polymer material for tires, comprising the following raw materials in parts by weight: 55-65 parts of polyurethane modified rubber, 25-30 parts of emulsion styrene-butadiene rubber, 6-10 parts of ethylene-acrylate rubber, 12-20 parts of composite resin, 10-13 parts of naphthenic rubber oil, 7-11 parts of hydroxyl-terminated polyisobutylene, 25-41 parts of composite reinforcing filler, 10-15 parts of composite plasticizer, 1.5-2.5 parts of titanate coupling agent, 1-1.5 parts of vulcanizing agent, 0.5-0.8 parts of co-crosslinking agent, 0.4-0.7 parts of vulcanization accelerator, and 1.5-2.5 parts of vulcanization accelerator auxiliary agent; The composite resin is composed of petroleum resin and terpene resin; The composite reinforcing filler includes carbon black, nano-activated calcium carbonate, and white carbon black; The raw materials for preparing polyurethane modified rubber include epoxidized natural rubber, aliphatic polyurethane prepolymer, and catalyst.

[0005] Preferably, the polyurethane modified rubber is prepared by reacting epoxidized natural rubber with aliphatic polyurethane prepolymer and mercapto-containing compounds under the action of a catalyst.

[0006] Preferably, the preparation method of the polyurethane modified rubber is as follows: epoxidized natural rubber is dissolved in tetrahydrofuran and stirred to form a uniform solution. Aliphatic polyurethane prepolymer is added and mixed evenly. Then, a mercapto-containing compound is added and stirred evenly. Then, a catalyst, dibutyltin dilaurate, is added and stirred. The mixture is reacted at a temperature of 45~60℃ for 3~4 hours. Deionized water is then added and stirred at 3000~4000 rpm to form an emulsion. The tetrahydrofuran is removed by rotary evaporation, and the mixture is centrifuged and dried to obtain the polyurethane modified rubber.

[0007] Preferably, the isocyanate group content of the aliphatic polyurethane prepolymer is 8-15%.

[0008] Preferably, the epoxidized natural rubber has an epoxidation degree of 25-45%.

[0009] Preferably, the amount of the aliphatic polyurethane prepolymer is 25-40% of the epoxidized natural rubber.

[0010] Preferably, the mercapto-containing compound is 7-15% of epoxidized natural rubber.

[0011] Preferably, the mercapto-containing compound is one or more of pentaerythritol tetra(3-mercaptopropionate), 2-hydroxyethyl disulfide, or bis(2-hydroxyethyl) disulfide.

[0012] Preferably, the composite reinforcing filler is composed of carbon black, nano-activated calcium carbonate, white carbon black, and modified montmorillonite.

[0013] Preferably, the composite reinforcing filler is composed of carbon black, nano-activated calcium carbonate, white carbon black and modified montmorillonite in a mass ratio of 2.5~3.5:1.5~2.5:1~2:1; more preferably 3:2:1.5:1.

[0014] Preferably, the modified montmorillonite is obtained by ion exchange intercalation of nano-montmorillonite with a cationic surfactant.

[0015] Preferably, the cationic surfactant is a quaternary ammonium salt cationic surfactant.

[0016] Preferably, the quaternary ammonium salt cationic surfactant is hexadecyltrimethylammonium bromide or octadecyltrimethylammonium chloride.

[0017] Preferably, the nano-montmorillonite is nano-sodium-based montmorillonite or nano-calcium-based montmorillonite.

[0018] Preferably, the modified montmorillonite is prepared by: dispersing nano-montmorillonite in deionized water and stirring to form a montmorillonite suspension; dissolving a cationic surfactant in deionized water to form a surfactant solution; adding the surfactant solution dropwise to the montmorillonite suspension under stirring conditions; reacting at 55-65°C for 3-4 hours; centrifuging, drying, and grinding to obtain the modified montmorillonite.

[0019] Preferably, the amount of the cationic surfactant is 28-42% of the mass of the nano-montmorillonite.

[0020] Preferably, the composite resin is composed of petroleum resin and terpene resin in a mass ratio of 2 to 3:1; Preferably, the petroleum resin is one of petroleum resin C5, petroleum resin C9, or C5 / C9 copolymer resin; preferably, it is C5 / C9 copolymer resin.

[0021] Preferably, the molecular weight of the hydroxyl-terminated polyisobutylene is 6000~12000 g / mol.

[0022] Preferably, the nano-activated calcium carbonate is obtained by calcining limestone to produce calcium oxide, adding water to form a calcium hydroxide suspension, then carbonizing it with carbon dioxide, and adding trisodium phosphate crystal form regulator to obtain uniform cubic particles.

[0023] Preferably, the composite plasticizer is composed of dioctyl phthalate and epoxidized soybean oil in a mass ratio of 1.5 to 2:1.

[0024] This invention also provides a method for preparing a polymer self-healing material for tires, comprising the following steps: (1) Dissolve the titanate coupling agent in anhydrous ethanol to form a 10-15 wt% titanate coupling agent mixture, stir the composite reinforcing filler and spray the titanate coupling agent mixture evenly, then stir and dry to form a modified composite reinforcing filler. (2) In a mixer, polyurethane modified rubber, emulsion styrene-butadiene rubber and ethylene-acrylate rubber are mixed at a temperature of 125~135℃ for 180~300s, and then vulcanization accelerator is added and mixed evenly to obtain the base rubber compound. (3) Add composite resin, naphthenic rubber oil and modified composite reinforcing filler to the base rubber compound, and mix at 110~120℃ for 150~260s to obtain the mixed primary rubber. (4) Add primary compound, hydroxyl-terminated polyisobutylene core and composite plasticizer to the primary compound, and mix at 80~90℃ for 120~210s to obtain the master compound. (5) Add vulcanizing agent, crosslinking agent and vulcanization accelerator to the masterbatch and mix at 90~100℃ for 100~160s to obtain a self-healing polymer material for tires.

[0025] The beneficial effects of the present invention are as follows: 1. The self-healing polymer material for tires of the present invention is a polymer combination system made by blending and compounding raw materials such as polyurethane modified rubber, latex styrene-butadiene rubber, ethylene-acrylate rubber, composite resin, cycloalkyl rubber oil and hydroxyl-terminated polyisobutylene, and with the synergistic effect of composite reinforcing fillers. The prepared self-healing polymer material has strong adhesion to the tire, can realize the self-healing function of the tire, improve the air tightness of the tire, and greatly improve the tire's anti-puncture and anti-leakage function.

[0026] 2. This invention uses polyurethane-modified rubber prepared by reacting epoxidized natural rubber, aliphatic polyurethane prepolymer and / or mercapto-containing compounds under the action of a catalyst to improve the rapid self-healing performance of polymer materials, while endowing them with excellent mechanical properties such as tensile strength and tear strength.

[0027] 3. The composite reinforcing filler used in this invention includes carbon black, nano-activated calcium carbonate and white carbon black, which can optimize the strength and adhesion of polymer materials and improve their self-healing efficiency.

[0028] 4. This invention further adds modified montmorillonite, which forms a "lamellae-particle" composite structure with carbon black, an alternating "rigid-flexible" structure with nano-activated calcium carbonate, and a "silicon-aluminum" composite network structure with silica. This synergistic effect of multiple structures forms a multi-level synergistic network structure, which not only enhances the binding force and interfacial bonding of the polymer composite system, disperses stress, and improves the tensile strength and tear strength of the polymer material, but also optimizes the composite reinforcing filler to form a new physical or chemical bonding mechanism with the polymer composite system, rapidly repairs cracks, and significantly improves the self-healing efficiency of the polymer material.

[0029] 5. This invention uses hydroxyl-terminated polyisobutylene, which contains hydroxyl functional groups that synergistically form a dynamic bond network structure with polyurethane modified rubber, latex styrene-butadiene rubber, and ethylene-acrylate rubber. The synergistic effect of the composite resin composed of petroleum resin and terpene resin is more obvious, optimizing the closure and adhesion of cracks in the self-healing process, improving the bond density and strength, and thus optimizing the mechanical properties and self-healing ability of polymer self-healing materials. Detailed Implementation

[0030] The following is a clear and complete description of the technical solutions in the implementation of this invention. The described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents, instruments, or components used that do not specify the manufacturer are all conventional products that can be purchased commercially.

[0031] This invention provides a self-healing polymer material for tires, characterized by comprising the following raw materials in parts by weight: 55-65 parts of polyurethane modified rubber, 25-30 parts of emulsion styrene-butadiene rubber, 6-10 parts of ethylene-acrylate rubber, 12-20 parts of composite resin, 10-13 parts of naphthenic rubber oil, 7-11 parts of hydroxyl-terminated polyisobutylene, 25-41 parts of composite reinforcing filler, 10-15 parts of composite plasticizer, 1.5-2.5 parts of titanate coupling agent, 1-1.5 parts of vulcanizing agent, 0.5-0.8 parts of co-crosslinking agent, 0.4-0.7 parts of vulcanization accelerator, and 1.5-2.5 parts of vulcanization accelerator aid; wherein, The composite resin is composed of petroleum resin and terpene resin; the composite reinforcing filler includes carbon black, nano-activated calcium carbonate and white carbon black; the ethylene-acrylate rubber is AEM rubber; the naphthenic rubber oil is preferably naphthenic oil KN4006; the titanate coupling agent is preferably titanate coupling agent 105; the vulcanizing agent is preferably dicumyl peroxide; the vulcanizing agent co-crosslinking agent is preferably triallyl isocyanurate; the vulcanization accelerator is preferably a thiuram-based vulcanization accelerator, preferably DPTT; the vulcanization accelerator is preferably a mixture of nano-zinc oxide and stearic acid, wherein the mass ratio of nano-zinc oxide to stearic acid is 2~3:1, preferably 2:1, i.e., a nano-zinc oxide / stearic acid system.

[0032] A further technical solution, nano-activated calcium carbonate, is obtained by calcining limestone to produce calcium oxide, adding water to form a calcium hydroxide suspension, then carbonizing it with carbon dioxide, and adding trisodium phosphate crystal form regulator to obtain uniform cubic particles.

[0033] A further technical solution involves preparing polyurethane-modified rubber by dissolving 100g of epoxidized natural rubber with an epoxidation degree of 25-45% in 1500ml of tetrahydrofuran, stirring at 300-500 rpm for 2-3 hours to form a homogeneous solution, adding an aliphatic polyurethane prepolymer with an isocyanate group content of 8-15%, wherein the amount of the aliphatic polyurethane prepolymer is 25-40% of the epoxidized natural rubber, and stirring at 500-800 rpm for 30-60 minutes. Then, a mercapto-containing compound is added, wherein the amount of the mercapto-containing compound is 7-15% of the epoxidized natural rubber, and the mercapto-containing compound is one or more of pentaerythritol tetra(3-mercaptopropionate), 2-hydroxyethyl disulfide, or bis(2-hydroxyethyl) disulfide. The mixture is stirred at 800-1000 rpm for 15-30 minutes, and then a catalyst, dibutyltin dilaurate, is added. Stir at rpm for 5-10 minutes, heat to 45-60℃ and keep warm for 3-4 hours, then add 3000 ml of deionized water and stir at 3000-4000 rpm to form an emulsion. Remove tetrahydrofuran by rotary evaporation, filter and dry to obtain polyurethane modified rubber.

[0034] The polyurethane prepolymer used in this invention is an aliphatic polyurethane prepolymer with an isocyanate group content of 8-15% obtained by reacting isophorone diisocyanate and polytetrahydrofuran ether diol with an NCO / OH ratio of 1:1 under the action of dibutyltin dilaurate catalyst.

[0035] A further technical solution involves preparing modified montmorillonite by dispersing 10g of nano-sodium-based montmorillonite or nano-calcium-based montmorillonite in 150ml of deionized water and stirring at 300-500 rpm to form a montmorillonite suspension. A quaternary ammonium salt cationic surfactant, comprising 28-42% of the montmorillonite mass, is dissolved in 80-90ml of deionized water. The quaternary ammonium salt cationic surfactant is either hexadecyltrimethylammonium bromide or octadecyltrimethylammonium chloride, forming a surfactant solution. Under stirring at 500-800 rpm, the surfactant solution is added dropwise to the montmorillonite suspension, and the mixture is reacted at 55-65℃ for 3-4 hours. After centrifugation, drying, and grinding, modified montmorillonite is obtained.

[0036] A further technical solution is that the composite resin is composed of petroleum resin and terpene resin in a mass ratio of 2 to 3:1; the petroleum resin is petroleum resin C5 or petroleum resin C9 or C5 / C9 copolymer resin.

[0037] A further technical solution is that the composite resin, petroleum resin, is a C5 / C9 copolymer resin. A further technical solution involves hydroxyl-terminated polyisobutylene with a molecular weight of 6000~12000 g / mol.

[0038] A further technical solution is that the composite reinforcing filler is composed of carbon black, nano-activated calcium carbonate, white carbon black and modified montmorillonite; the mass ratio of carbon black, nano-activated calcium carbonate, white carbon black and modified montmorillonite is 2.5~3.5:1.5~2.5:1~2:1, preferably 3:2:1.5:1.

[0039] This invention also provides a method for preparing a polymer self-healing material for tires, comprising the following steps: (1) Dissolve the titanate coupling agent in anhydrous ethanol to form a 10-15 wt% titanate coupling agent mixture, stir the composite reinforcing filler and spray the titanate coupling agent mixture evenly, then stir and dry to form a modified composite reinforcing filler. (2) In a mixer, polyurethane modified rubber, emulsion styrene-butadiene rubber and ethylene-acrylate rubber are mixed at a temperature of 125~135℃ for 180~300s, and then vulcanization accelerator is added and mixed evenly to obtain the base rubber compound. (3) Add composite resin, naphthenic rubber oil and modified composite reinforcing filler to the base rubber compound, and mix at 110~120℃ for 150~260s to obtain the mixed primary rubber. (4) Add primary compound, hydroxyl-terminated polyisobutylene core and composite plasticizer to the primary compound, and mix at 80~90℃ for 120~210s to obtain the master compound. (5) Add vulcanizing agent, crosslinking agent and vulcanization accelerator to the masterbatch and mix at 90~100℃ for 100~160s to obtain a self-healing polymer material for tires.

[0040] Preparation Example 1: A method for preparing polyurethane-modified rubber: 100g of epoxidized natural rubber with an epoxidation degree of 30% was dissolved in 1500ml of tetrahydrofuran and stirred at 400 rpm for 2.5h to form a homogeneous solution. 35g of aliphatic polyurethane prepolymer with an isocyanate group content of 10% was added and stirred at 600 rpm for 45min. Then, 8g of pentaerythritol tetra(3-mercaptopropionate) was added and stirred at 800-1000 rpm for 20min. Then, 0.25g of dibutyltin dilaurate catalyst was added and stirred at 900 rpm for 10min. The mixture was heated to 55℃ and kept at that temperature for 3.5h. Then, 3000ml of deionized water was added and stirred at 3500rpm to form an emulsion. The tetrahydrofuran was removed by rotary evaporation, filtered, and dried to obtain polyurethane modified rubber.

[0041] Preparation Example 2: A method for preparing modified montmorillonite: 10g of nano-sodium montmorillonite was dispersed in 150ml of deionized water and stirred at 400 rpm to form a montmorillonite suspension. 4g of hexadecyltrimethylammonium bromide was dissolved in 80ml of deionized water to form a surfactant solution. The surfactant solution was added dropwise to the montmorillonite suspension under stirring at 600 rpm, and the reaction was carried out at 60℃ for 3.5h. After centrifugation, drying, and grinding, modified montmorillonite was obtained.

[0042] Example 1 A self-healing polymer material for tires and its preparation method, comprising the following steps: (1) Weigh the raw materials according to the following weight parts to prepare Example 1: 55 parts of polyurethane modified rubber, 28 parts of emulsion styrene-butadiene rubber, 8 parts of AEM rubber, 12 parts of composite resin, 10 parts of naphthenic oil KN4006, 11 parts of hydroxyl-terminated polyisobutylene, 36 parts of composite reinforcing filler, 10 parts of composite plasticizer, 2 parts of titanate coupling agent, 1 part of dicumyl peroxide, 0.6 parts of triallyl isocyanurate, 0.6 parts of accelerator DPTT, and 2 parts of nano zinc oxide / stearic acid system; the composite resin is composed of C5 / C9 copolymer resin and terpene resin in a mass ratio of 2.5:1; the composite plasticizer is composed of dioctyl phthalate and epoxidized soybean oil in a mass ratio of 1.8:1; the composite reinforcing filler is composed of carbon black, nano activated calcium carbonate, and white carbon black in a mass ratio of 2.5:2:1; the molecular weight of hydroxyl-terminated polyisobutylene is 6000 g / mol; (2) Dissolve the titanate coupling agent in anhydrous ethanol to form a 15wt% titanate coupling agent mixture, stir the composite reinforcing filler and spray the titanate coupling agent mixture evenly, then stir and dry to form a modified composite reinforcing filler. (3) In a mixer, polyurethane modified rubber, emulsion styrene-butadiene rubber and AEM rubber are mixed at 125°C for 300s, and then nano zinc oxide / stearic acid system is added and mixed evenly to obtain the base rubber compound. (4) Add composite resin, naphthenic oil KN4006 and modified composite reinforcing filler to the base rubber compound, and mix at 110℃ for 210s to obtain the initial compound. (5) Add primary compound, hydroxyl-terminated polyisobutylene core and composite plasticizer to the primary compound, and mix at 85°C for 120s to obtain the master compound. (6) Add dicumyl peroxide, triallyl isocyanurate and accelerator DPTT to the masterbatch and mix at 95°C for 160s to obtain a self-healing polymer material for tires.

[0043] Example 2 A self-healing polymer material for tires and its preparation method, comprising the following steps: (1) Weigh the raw materials according to the following weight parts to prepare Example 1: 60 parts of polyurethane modified rubber, 30 parts of emulsion styrene-butadiene rubber, 6 parts of AEM rubber, 20 parts of composite resin, 10 parts of naphthenic oil KN4006, 7 parts of hydroxyl-terminated polyisobutylene, 25 parts of composite reinforcing filler, 12 parts of composite plasticizer, 1.5 parts of titanate coupling agent, 1.2 parts of dicumyl peroxide, 0.8 parts of triallyl isocyanurate, 0.4 parts of accelerator DPTT, and 1.5 parts of nano zinc oxide / stearic acid system; the composite resin is composed of C5 / C9 copolymer resin and terpene resin in a mass ratio of 3:1; the composite plasticizer is composed of dioctyl phthalate and epoxidized soybean oil in a mass ratio of 1.5:1; the composite reinforcing filler is composed of carbon black, nano activated calcium carbonate, and white carbon black in a mass ratio of 3:1:1; the molecular weight of hydroxyl-terminated polyisobutylene is 8000 g / mol; (2) Dissolve the titanate coupling agent in anhydrous ethanol to form a 10wt% titanate coupling agent mixture, stir the composite reinforcing filler and spray the titanate coupling agent mixture evenly, then stir and dry to form a modified composite reinforcing filler. (3) Polyurethane modified rubber, emulsion styrene-butadiene rubber and AEM rubber are mixed in an internal mixer at 130°C for 260s, and then nano zinc oxide / stearic acid system is added and mixed evenly to obtain the base rubber compound. (4) Add composite resin, naphthenic oil KN4006 and modified composite reinforcing filler to the base rubber compound, and mix at 115℃ for 260s to obtain the initial compound. (5) Add primary compound, hydroxyl-terminated polyisobutylene core and composite plasticizer to the primary compound, and mix at 80°C for 120s to obtain the master compound. (6) Add dicumyl peroxide, triallyl isocyanurate and thiuram-type vulcanization accelerator to the masterbatch and mix at 90°C for 1020s to obtain a self-healing polymer material for tires.

[0044] Example 3 A self-healing polymer material for tires and its preparation method, comprising the following steps: (1) Weigh the raw materials according to the following weight parts to prepare Example 1: 65 parts of polyurethane modified rubber, 25 parts of emulsion styrene-butadiene rubber, 10 parts of AEM rubber, 16 parts of composite resin, 13 parts of naphthenic oil KN4006, 9 parts of hydroxyl-terminated polyisobutylene, 41 parts of composite reinforcing filler, 15 parts of composite plasticizer, 2.5 parts of titanate coupling agent, 1.5 parts of dicumyl peroxide, 0.5 parts of triallyl isocyanurate, 0.7 parts of accelerator DPTT, and 2.5 parts of nano zinc oxide / stearic acid system; the composite resin is composed of C5 / C9 copolymer resin and terpene resin in a mass ratio of 2:1; the composite plasticizer is composed of dioctyl phthalate and epoxidized soybean oil in a mass ratio of 2:1; the composite reinforcing filler is composed of carbon black, nano activated calcium carbonate, and white carbon black in a mass ratio of 2:1.5:1; the molecular weight of hydroxyl-terminated polyisobutylene is 12000 g / mol; (2) Dissolve the titanate coupling agent in anhydrous ethanol to form a 15wt% titanate coupling agent mixture, stir the composite reinforcing filler and spray the titanate coupling agent mixture evenly, then stir and dry to form a modified composite reinforcing filler. (3) In a mixer, polyurethane modified rubber, emulsion styrene-butadiene rubber and AEM rubber are mixed at a temperature of 125~135℃ for 180~300s, and then nano zinc oxide / stearic acid system is added and mixed evenly to obtain the base rubber compound. (4) Add composite resin, naphthenic oil KN4006 and modified composite reinforcing filler to the base rubber compound, and mix at 110~120℃ for 150~260s to obtain the mixed primary rubber compound. (5) Add primary compound, hydroxyl-terminated polyisobutylene core and composite plasticizer to the primary compound, and mix at 80~90℃ for 120~210s to obtain the master compound. (6) Add dicumyl peroxide, triallyl isocyanurate and accelerator DPTT to the masterbatch and mix at 90~100℃ for 100~160s to obtain a self-healing polymer material for tires.

[0045] Example 4: A polymer self-healing material for tires and its preparation method, which differs from Example 1 in that: the composite reinforcing filler is composed of carbon black, nano-active calcium carbonate, white carbon black and modified montmorillonite from Preparation Example 2 in a mass ratio of 3:2:1.5:1.

[0046] Example 5: A self-healing polymer material for tires and its preparation method, which differs from Example 1 in that the composite resin is composed of petroleum resin C5 and terpene resin in a mass ratio of 2.5:1.

[0047] Example 6: A self-healing polymer material for tires and its preparation method, which differs from Example 1 in that the composite resin is composed of petroleum resin C9 and terpene resin in a mass ratio of 2.5:1.

[0048] Example 7: A self-healing polymer material for tires and its preparation method, differing from Example 1 in that: Polyurethane modified rubber: 100g of epoxidized natural rubber with an epoxidation degree of 30% was dissolved in 1500ml of tetrahydrofuran and stirred at 400 rpm for 2.5h to form a homogeneous solution. 35g of aliphatic polyurethane prepolymer with an isocyanate group content of 10% was added and stirred at 600 rpm for 45min. Then, 0.25g of dibutyltin dilaurate catalyst was added and stirred at 900 rpm for 10min. The mixture was heated to 55℃ and kept at that temperature for 3.5h. Then, 3000ml of deionized water was added and stirred at 3500rpm to form an emulsion. The tetrahydrofuran was removed by rotary evaporation, filtered, and dried to obtain polyurethane modified rubber.

[0049] Comparative Example 1: A self-healing polymer material for tires and its preparation method, which differs from Example 1 in that: epoxidized natural rubber with an epoxidation degree of 30% is used instead of the polyurethane modified rubber in Example 1.

[0050] Comparative Example 2: A self-healing polymer material for tires and its preparation method, which differs from Example 1 in that: polyisobutylene replaces hydroxyl-terminated polyisobutylene, and the polyisobutylene is polyisobutylene with no active groups at the end groups.

[0051] Comparative Example 3 is a self-healing polymer material for tires and its preparation method, which differs from Example 1 in that: 63 parts of polyurethane modified rubber and 0 parts of AEM rubber are used.

[0052] Comparative Example 4: A self-healing polymer material for tires and its preparation method, which differs from Example 1 in that: C5 / C9 copolymer resin is used instead of composite resin.

[0053] Comparative Example 5: A self-healing polymer material for tires and its preparation method, which differs from Example 1 in that: terpene resin is used instead of composite resin.

[0054] Comparative Example 6: A polymer self-healing material for tires and its preparation method, which differs from Example 1 in that the composite reinforcing filler is composed of carbon black and white carbon black in a mass ratio of 2:1.

[0055] Comparative Example 7: A polymeric self-healing material for tires and its preparation method, which differs from Example 1 in that the composite reinforcing filler is composed of nano-active calcium carbonate and white carbon black in a mass ratio of 2.5:1.

[0056] Comparative Example 8: A polymeric self-healing material for tires and its preparation method, which differs from Example 1 in that the composite reinforcing filler is composed of carbon black and nano-activated calcium carbonate in a mass ratio of 2.5:2.

[0057] Comparative Example 9: A polymer self-healing material for tires and its preparation method, which differs from Example 1 in that: the composite reinforcing filler is composed of carbon black, white carbon black and modified montmorillonite from Preparation Example 2 in a mass ratio of 3:1.5:1.

[0058] Comparative Example 10: A polymeric self-healing material for tires and its preparation method, which differs from Example 1 in that the composite reinforcing filler is composed of carbon black, nano-activated calcium carbonate and modified montmorillonite from Preparation Example 2 in a mass ratio of 3:2:1.

[0059] Comparative Example 11: A polymer self-healing material for tires and its preparation method, which differs from Example 1 in that: the composite reinforcing filler is composed of nano-active calcium carbonate, white carbon black and modified montmorillonite from Preparation Example 2 in a mass ratio of 2:1.5:1.

[0060] Comparative Example 12: A self-healing polymer material for tires and its preparation method, which differs from Example 4 in that: nano-sodium-based montmorillonite is used instead of the modified montmorillonite in Preparation Example 2.

[0061] Mechanical property test Effect Experiment Example 1 The polymer self-healing materials of Examples 1-7 and Comparative Examples 1-13 were melted and placed in a roller extruder for calendering and vulcanization molding. The tensile strength (MPa), elongation at break (%), low temperature (-30℃) resilience (%) and tear strength (KN / m) of the materials were determined with reference to GB / T 528-2009, GB / T 1681-2009 and GB / T 529-2008, as shown in Table 1.

[0062] Effect Experiment Example 2 The self-healing polymer materials of Examples 1-7 and Comparative Examples 1-13 were melted and placed in a roller extruder for calendering. Then, they were molded and vulcanized with the inner wall of the tire using conventional tire manufacturing processes. After cooling, samples stored at room temperature of 25°C, samples stored at low temperature of -30°C for 48 hours, and samples stored at high temperature of 120°C for 4 hours were peeled off using a DCS-500 universal testing machine to test their adhesion force (N / m), as shown in Table 1.

[0063] Table 1 Mechanical Properties

[0064] Self-repair efficiency performance test Effect Experiment Example 3 The self-healing polymer materials of Examples 1, 4, 7 and Comparative Examples 1-13 were melted and placed in a roller extruder for calendering and vulcanization molding. Their original tensile strength was tested with a tensile testing machine. Then, an unstretched strip was cut in the middle with a depth of 10 mm and a length of 20 mm. It was kept at room temperature of 25°C for 18 h, at low temperature of -30°C for 36 h, and at 120°C for 2 h to obtain the repaired strip. Its tensile strength was then tested with a tensile testing machine. The self-healing rate of the examples and comparative examples before and after repair was calculated. The self-healing rate = (tensile strength of the strip after repair / original tensile strength of the strip) × 100%, as shown in Table 2.

[0065] Table 2 Self-repair rate

[0066] From Table 2 above, combined with Table 1, this invention uses a composite resin composed of hydroxyl-terminated polyisobutylene, petroleum resin, and terpene resin, and synergistically combines it with a composite reinforcing filler made of at least carbon black, nano-activated calcium carbonate, and white carbon black, along with polyurethane-modified rubber, latex styrene-butadiene rubber, and ethylene-acrylate rubber. Furthermore, it employs polyurethane-modified rubber prepared by reacting epoxidized natural rubber, aliphatic polyurethane prepolymer, and / or mercapto-containing compounds under a catalyst. This results in a multi-layered synergistic network structure with significant synergistic effects, giving the polymer self-healing material excellent tensile strength, tear strength, and other mechanical properties, and strong adhesion to tires. Simultaneously, it exhibits a high self-healing rate within a wide temperature range of -30 to 120°C, enabling rapid crack repair and improving its self-healing efficiency.

[0067] Self-sealing performance test Effect Experiment Example 4 The polymer self-healing materials of Examples 1, 4, 7 and Comparative Examples 1-13 were coated with a 4.5mm layer using conventional processes on three types of tires: model 195 / 60R16, model 235 / 50R17, and model 10R22.5. A 10mm diameter screw was used, and the self-sealing performance of the tires was tested according to GB / T38510-2020. The tires were punctured using a tire puncture device, and the tires were tested for air leakage when the puncture width was 10cm. The method for observing air leakage was as follows: foam water was sprayed onto the puncture / damage surface; if there was air leakage, foam would be generated. The greater the degree of air leakage, the more abundant the foam, as shown in Table 3.

[0068] Table 3 Self-sealing properties

[0069] Table 3 shows that the tires made using the coatings of Examples 1, 4, and 7 exhibited minimal change in tire pressure after being punctured by a screw, and no rubber material was extruded after the screw was removed. This indicates that the coating made using the polymer self-healing material provided by this invention provides good self-sealing properties for the tires. In particular, Example 4, with its polyurethane modified rubber containing the synergistic effect of pentaerythritol tetra(3-mercaptopropionate) and the synergistic effect of modified montmorillonite with carbon black, nano-active calcium carbonate, and white carbon black, significantly improves the self-sealing properties of the tire, resulting in almost no change in tire pressure compared to the initial tire pressure. Comparing Example 1 and Comparative Examples 1-12, in the polymer self-healing materials, epoxidized natural rubber is not modified, polyisobutylene lacks end-group active groups, AEM rubber is lacking, there is no synergistic effect of petroleum resin and terpene resin, the composite reinforcing filler lacks any of carbon black, nano-active calcium carbonate and white carbon black, and montmorillonite is not modified. Due to the influence of any of these factors, more foam is generated after spraying foam water on the tire, which reduces the enhancement effect of the polymer self-healing material on the tire's self-sealing performance.

[0070] High-speed and durability performance tests Effect Experiment Example 5 The polymer self-healing materials of Examples 1, 4, 7, and Comparative Examples 1-13 were coated with a 4.5mm layer using conventional processes on tires of model 275 / 40R19 101Y. The location, number, and depth of the punctures were inspected according to GB / T 38510-2020. 1) After removing the punctures, the tires were left to stand for 3 hours, and then a high-speed performance test was conducted according to GB / T 4502-2016. The test environment temperature was 37.8℃~38.6℃, starting from 240km / h, increasing by 10km / h every 10 minutes until reaching 290km / h, with a test duration of 60 minutes; 2) After removing the punctures, the tires were left to stand for 3 hours, and then a durability performance test was conducted according to GB / T 4502-2016. The test environment temperature was 36.3℃~37.9℃, with a cumulative time ≥34 hours; 3) After punctures, the tires were left to stand for 3 hours, and then a high-speed performance test was conducted according to GB / T 4502-2016. Durability tests were conducted according to 4502-2016, with an ambient temperature of 36.3℃~37.9℃ and a cumulative time of ≥34h.

[0071] After the test, check the following requirements: ① Air pressure retention rate: ≥95%; ② Appearance (tread, sidewall, ply, belt or buffer layer, bead): There should be no delamination, ply cracks, cord peeling, cord breakage, chipping, joint cracking, crazing, or abnormal tire deformation; ③ Self-sealing layer: No accumulation, bulges, degumming, obvious wrinkling, or displacement. Observe whether it meets the requirements, as shown in Table 4.

[0072] Table 4 High-speed and durability performance

[0073] Table 4 shows that tires made using the coatings of Examples 1, 4 and 7 all met the requirements for air pressure retention, appearance, and self-sealing layer after high-speed performance and durability tests. This indicates that the polymer self-healing material provided by the present invention has excellent durability and adhesion in the coating, which can help increase the quietness and comfort of the tire and improve vehicle safety performance.

[0074] In summary, the self-healing polymer material for tires prepared by this invention can achieve the self-healing function of tires, has excellent durability and adhesion, greatly improves the tire's anti-puncture and anti-leakage functions, helps to improve the tire's quietness and comfort, and thus enhances vehicle safety performance.

[0075] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit and essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0076] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A self-healing polymer material for tires, characterized in that, The composition includes 55-65 parts of polyurethane modified rubber, 25-30 parts of emulsion styrene-butadiene rubber, 6-10 parts of ethylene-acrylate rubber, 12-20 parts of composite resin, 10-13 parts of naphthenic rubber oil, 7-11 parts of hydroxyl-terminated polyisobutylene, 25-41 parts of composite reinforcing filler, 10-15 parts of composite plasticizer, 1.5-2.5 parts of titanate coupling agent, 1-1.5 parts of vulcanizing agent, 0.5-0.8 parts of co-crosslinking agent, 0.4-0.7 parts of vulcanization accelerator, and 1.5-2.5 parts of vulcanization accelerator aid. The composite resin is composed of petroleum resin and terpene resin; The composite reinforcing filler includes carbon black, nano-activated calcium carbonate, and white carbon black; The raw materials for preparing polyurethane modified rubber include epoxidized natural rubber, aliphatic polyurethane prepolymer, and catalyst.

2. The self-healing polymer material for tires and its preparation method according to claim 1, characterized in that, The polyurethane-modified rubber is prepared by reacting epoxidized natural rubber, aliphatic polyurethane prepolymer, and mercapto-containing compounds under the action of a catalyst.

3. The self-healing polymer material for tires and its preparation method according to claim 2, characterized in that, The preparation method of the polyurethane modified rubber is as follows: epoxidized natural rubber is dissolved in tetrahydrofuran and stirred to form a uniform solution. Aliphatic polyurethane prepolymer is added and mixed evenly. Then, a mercapto-containing compound is added and stirred evenly. Then, the catalyst dibutyltin dilaurate is added and stirred. The reaction is carried out at a temperature of 45~60℃ for 3~4h. Then, deionized water is added and stirred at 3000~4000rpm to form an emulsion. Tetrahydrofuran is removed by rotary evaporation. After centrifugation and drying, polyurethane modified rubber is obtained. The mercapto-containing compound is 7-15% of epoxidized natural rubber; The thiol-containing compound is one or more of pentaerythritol tetra(3-mercaptopropionate), 2-hydroxyethyl disulfide, or bis(2-hydroxyethyl) disulfide.

4. The self-healing polymer material for tires and its preparation method according to claim 1, characterized in that, The amount of the aliphatic polyurethane prepolymer used is 25-40% of the epoxidized natural rubber; The isocyanate group content of the aliphatic polyurethane prepolymer is 8-15%; the epoxidation degree of the epoxidized natural rubber is 25-45%.

5. The self-healing polymer material for tires and its preparation method according to claim 1, characterized in that, The composite reinforcing filler is composed of carbon black, nano-activated calcium carbonate, white carbon black, and modified montmorillonite.

6. The self-healing polymer material for tires and its preparation method according to claim 5, characterized in that, The modified montmorillonite is obtained by ion exchange intercalation of nano-montmorillonite with a cationic surfactant.

7. The self-healing polymer material for tires and its preparation method according to claim 6, characterized in that, The modified montmorillonite is prepared by: dispersing nano-montmorillonite in deionized water and stirring to form a montmorillonite suspension; dissolving a cationic surfactant in deionized water to form a surfactant solution; adding the surfactant solution dropwise to the montmorillonite suspension under stirring conditions; reacting at 55-65℃ for 3-4 hours; centrifuging, drying, and grinding to obtain the modified montmorillonite. The cationic surfactant is hexadecyltrimethylammonium bromide or octadecyltrimethylammonium chloride; the nano-montmorillonite is nano-sodium montmorillonite or nano-calcium montmorillonite. The amount of the cationic surfactant used is 28-42% of the mass of the nano-montmorillonite.

8. The self-healing polymer material for tires and its preparation method according to claim 1, wherein the petroleum resin is one of petroleum resin C5, petroleum resin C9, or C5 / C9 copolymer resin.

9. The self-healing polymer material for tires and its preparation method according to claim 1, characterized in that, The molecular weight of the hydroxyl-terminated polyisobutylene is 6000~12000 g / mol; The composite plasticizer is composed of dioctyl phthalate and epoxidized soybean oil.

10. A method for preparing a self-healing polymeric material for tires according to any one of claims 1 to 9, characterized in that, Includes the following steps: (1) Dissolve the titanate coupling agent in anhydrous ethanol to form a 10-15 wt% titanate coupling agent mixture, stir the composite reinforcing filler and spray the titanate coupling agent mixture evenly, then stir and dry to form a modified composite reinforcing filler. (2) In a mixer, polyurethane modified rubber, emulsion styrene-butadiene rubber and ethylene-acrylate rubber are mixed at a temperature of 125~135℃ for 180~300s, and then vulcanization accelerator is added and mixed evenly to obtain the base rubber compound. (3) Add composite resin, naphthenic rubber oil and modified composite reinforcing filler to the base rubber compound, and mix at 110~120℃ for 150~260s to obtain the mixed primary rubber. (4) Add primary compound, hydroxyl-terminated polyisobutylene core and composite plasticizer to the primary compound, and mix at 80~90℃ for 120~210s to obtain the master compound. (5) Add vulcanizing agent, crosslinking agent and vulcanization accelerator to the masterbatch and mix at 90~100℃ for 100~160s to obtain a self-healing polymer material for tires.

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