A self-sealing rubber composition for a safety tire, and a method of manufacturing and using the same

Abstract

The application belongs to the technical field of tire self-sealing glue, and specifically discloses a self-sealing glue composition of safety tires, and a preparation method and application thereof. The glue components include: base material, tackifier, two-phase filler, heat stabilizer, additive, dispersant, antioxidant, colorant; the base material is mixed rubber of butyl rubber and ethylene-propylene-diene rubber, the filler is a modified nano-aluminum oxide / titanium oxide two-phase composite, the heat stabilizer is a mixture of zinc stearate and epoxy soybean oil, the tackifier is a silane-terminated modified polybutadiene rubber, the additive is one of diatomite or bentonite, and the dispersant is polyvinyl alcohol. Through screening and modification of the components and the filler, the application improves the compatibility between the organic-inorganic components, promotes the dispersion of the filler in the base material, enhances the mechanical properties and thermal stability of the sealing glue, so that the sealing glue has excellent high and low temperature resistance, and also has a gain effect on the material self-sealing property.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of tire self-sealing glue, and particularly relates to a self-sealing glue composition for safety tires and a preparation method and application thereof. BACKGROUND

[0002] The accidents caused by tire damage during driving of vehicles are increasing, which affects the safety of vehicles and pedestrians at any time. The tire self-sealing glue is a preventive way for tire burst, and a layer of self-repairing sealing glue is coated in the tire, which can avoid air leakage and tire burst when the tire is damaged or pierced by a sharp object.

[0003] At present, butyl rubber, thermoplastic elastomer, styrene-butadiene rubber and halogenated butyl rubber are mainly used as the main material of the self-sealing glue, and inorganic materials such as zinc oxide, silicon oxide and calcium carbonate are used as the filling material, and various additives such as antioxidants, plasticizers, tackifiers, anti-aging agents and coupling agents are used, and the compatibility of the rubber products is usually poor, especially the dispersibility of the filler greatly affects the processing performance of the glue, which easily causes poor dispersion and unevenness, and further affects the mechanical properties, thermal stability and self-sealing performance of the glue itself. For example, due to the large temperature difference between north and south or summer and winter, some self-sealing glues on the market will soften at high temperature, causing strong fluidity and easily extruding to cause tire air leakage when pierced, or flowing and accumulating to cause tire imbalance when the vehicle is running at high speed. When pierced by a sharp object at low temperature, brittle fracture easily occurs. It is difficult to meet the demand of vehicle owners for tire puncture prevention when driving in different seasons or across regions. Therefore, the mixing quality of the glue relates to the degree of subsequent processing and the self-sealing performance of the glue. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a self-sealing glue composition for safety tires and a preparation method and application thereof. Through modification of the components and fillers, the compatibility between the organic-inorganic components is improved, the dispersion of the filler in the matrix is promoted, the components of the glue can play a synergistic effect, the mechanical properties and high and low temperature resistance of the glue are enhanced, the cost of the glue is lower, and the glue has good elasticity, strength and self-sealing property.

[0005] The present application achieves the above-mentioned purposes through the following technical solutions:

[0006] A first object of the present application is to provide a self-sealing glue for safety tires, which comprises the following components: a base material, a tackifier, an inorganic filler, a thermal stabilizer, an auxiliary agent, a dispersant, an anti-aging agent and a colorant. The base material is a mixed rubber of butyl rubber and ethylene-propylene-diene rubber, the inorganic filler is a modified nano-alumina / titanium oxide dual-phase composite, and the thermal stabilizer is a mixture of zinc stearate and epoxy soybean oil.

[0007] Further, the components are as follows in parts by weight: base material 58-75 parts, tackifier 4.0-6.5 parts, inorganic filler 16-25 parts, thermal stabilizer 2.3-4.0 parts, auxiliary agent 3.0-4.5 parts, dispersing agent 0.8-2.0 parts, antioxidant 0.2-1.5 parts, colorant 0.3-1.2 parts.

[0008] Further, the weight ratio of butyl rubber to ethylene-propylene-diene rubber in the base material is 2:3-3:2.

[0009] Further, the tackifier is a silane-terminated modified polybutadiene rubber.

[0010] Further, the silane-terminated modified polybutadiene rubber is one of Polyvest EP ST-E 60, Polyvest EP ST-E 100 (commercially available), and is a polybutadiene terminated with triethoxysilane.

[0011] Further, the weight ratio of zinc stearate to epoxy soybean oil in the thermal stabilizer is 2-5:1-3.

[0012] The composite thermal stabilizer is used in combination in the components of the sealant, and the use of zinc stearate and epoxy soybean oil together can enhance the thermal stability of the sealant. At the same time, the auxiliary agent diatomite or bentonite can reduce the moisture in the sealant, so that the thermal stabilizer is more stable and / or the thermal stabilizer captures free active groups more stably, further enhancing the thermal stability of the sealant, so that the sealant has excellent high and low temperature resistance.

[0013] Further, the inorganic filler is a modified nano-alumina / titanium oxide dual-phase composite prepared by the following method: polyvinylpyrrolidone and sodium alginate are used as surface treatment agents to modify nano-alumina, which is then dispersed in toluene to obtain a toluene dispersion of nano-alumina; acetic acid and triethanolamine are mixed, and tetrabutyl titanate is added and stirred to obtain a mixed solution, then the toluene dispersion of nano-alumina is added to the mixed solution, and the stirring is continued to obtain a sol, which is aged, dried, and ground to obtain the modified nano-alumina / titanium oxide dual-phase composite.

[0014] The modified alumina / titanium oxide dual-phase composite is used in the present application, polyvinylpyrrolidone and sodium alginate are used as surface treatment agents to modify alumina, which improves the interaction effect between the base material and the inorganic phase, interacts with the active sites in the base material, and further improves the high and low temperature resistance. At high temperatures, the sealant is stable, and the sealant and the tire air tight layer have a high adhesion force retention rate. At low temperatures, the brittleness and crack resistance of the sealant are reduced, and the self-sealing performance of the obtained sealant is effectively improved.

[0015] The existence of titanium oxide in the modified alumina / titanium oxide dual-phase system prepared in the application effectively reduces the interaction between alumina particles, promotes the dispersion of the filler in the matrix, and the rubber composite of the dual-phase filler has a lower degree of filler network and more uniform dispersion compared with the filler directly added with alumina / titanium dioxide, thereby significantly improving the elongation at break and tensile strength, improving the thixotropy and heat resistance of the rubber compound, reducing the difference in the thermal expansion coefficient between the sealant and the joint surface, and having a significant gain effect on the sealing effect of the material.

[0016] Further, in the specific embodiments of the application, the modified nano-alumina / titanium oxide dual-phase composite is prepared by the following specific steps:

[0017] 30-50 parts of nano-alumina, 1.5-4.2 parts of modified polyvinylpyrrolidone and sodium alginate, and 80-150 parts of water solution are added, the mass ratio of polyvinylpyrrolidone and sodium alginate is 3-5:1, ultrasonic treatment is carried out at room temperature for 15-20 min, stirring is carried out at 40-60℃ for 20-40 min, then the solid is washed with ethanol solution and dried to obtain modified nano-alumina, the modified nano-alumina is dispersed in toluene at a concentration of 0.07-0.1 g / mL, ultrasonic dispersion is carried out for 15-30 min; acetic acid and triethanolamine are mixed and stirred for 25-40 min, then tetrabutyl titanate is added to the reactor and stirred for 20-30 min to obtain a mixed solution, then the nano-alumina toluene dispersion is slowly added to the mixed solution, and stirring is continued for 1.5-2.5 h to obtain a sol, the sol is aged at room temperature for 10-12 h, then dried in an oven at 80-90℃, then ethanol is added, ball milling is carried out at a rotation speed of 300-500 r / min for 3-4 h, and then dried at 80-90℃ to obtain the modified nano-alumina / titanium oxide dual-phase filler; wherein the volume ratio of acetic acid, triethanolamine, tetrabutyl titanate and nano-alumina dispersion is 35.5-38.0 mL:2.5-3.2 mL:6.8-7.5 mL:20-25 mL.

[0018] Further, the auxiliary agent is one of diatomite or bentonite;

[0019] Further, the dispersant is polyvinyl alcohol.

[0020] Further, the antioxidant is at least two or more of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine (antioxidant 4020), 2-mercaptobenzimidazole (antioxidant MB), 4,4'-bis(dimethylbenzyl) diphenylamine (antioxidant 445), 4,4'-dioctyl diphenylamine (antioxidant ODA), 2,2,4-trimethyl 1,2-dihydroquinoline polymer (antioxidant RD), N-phenyl-N'-isopropyl-p-phenylenediamine (antioxidant 4010NA), etc.

[0021] Further, the colorant is carbon black or graphite powder.

[0022] A second object of the present application is to provide a preparation process of the self-sealing glue of the safety tire, which improves the compatibility and dispersibility between components by grouping and blending materials, adding glue components in sequence and using continuous temperature rising mode, and the preparation process comprises the following steps:

[0023] S1, blending the above-mentioned base material, tackifier and antioxidant, setting the temperature to 80-120℃, and stirring uniformly to obtain a mixture;

[0024] S2, adding the above-mentioned inorganic filler, heat stabilizer, auxiliary agent and dispersant, continuing to heat to 120-150℃ and stirring for a period of time;

[0025] S3, adding the colorant, heating to 180-220℃, stirring uniformly, vacuumizing to eliminate bubbles, and obtaining the product.

[0026] Further, the stirring time in step S1 is 25-40 min.

[0027] Further, the stirring time in step S2 is 1.5-3 h.

[0028] A third object of the present application is to provide an application of the above-mentioned sealing glue in the preparation of the self-sealing safety tire, and the application is to melt the self-sealing glue, and then use spraying equipment to uniformly spray the glue on the inner surface of the tire.

[0029] Further, the melting temperature is 190-210℃, and the spraying thickness is 3-6 mm.

[0030] A fourth object of the present application is to provide an integrated vulcanized self-sealing safety tire, which comprises the above-mentioned sealing glue layer, and the tire is obtained by melting the sealing glue, placing it in a roll extruder for calendering molding, pressing and compounding the glue strip with the transition layer glue on one side, protecting the other side with a high-temperature resistant isolation film, then pasting the transition layer on the inner side of the innermost airtight layer of the tire, positioning the glue strip on the tire embryo, rotating and pasting and compacting, and then vulcanizing the tire after molding by the tire molding machine.

[0031] In a specific embodiment of the present application, the transition layer rubber compound is composed of butyl rubber and natural rubber, EVA, C5 resin, dioctyl sebacate (DOS), calcium carbonate, kaolin, carbon black and antioxidant 2246. After mixing and heating in a reaction kettle, the material is discharged and coated, and both sides are pasted with release films for standby. One side of the transition layer is attached to the sealant, and the other side is attached to the inner side of the innermost air-tight layer of the tire. During the vulcanization process, the transition layer and the self-sealing glue interact with each other, and the cross-linked part of the transition layer can cross-link with the tire matrix air-tight layer, and the un-cross-linked part is fused with the self-sealing glue to form a tightly bonded body, which is seamlessly attached to the tire.

[0032] The self-sealing glue tire prepared by the present application does not delaminate, does not flow, and does not crack under high or low temperature use conditions, ensuring the balance and safety of the tire. It can prevent air leakage after being pierced by a nail, and can play a role in preventing leakage and self-sealing, and after the foreign object is pulled out, the glue material quickly blocks the hole under the action of tire pressure to slow down the loss of air pressure.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] (1) The present application provides a self-sealing glue formula for safe tires by selecting the components of the glue, which can enhance the thermal stability of the sealant under the action of the scientific compatibility of each component, so that the sealant has excellent high and low temperature resistance, and can not delaminate, flow or crack under the condition of-45℃~120℃, and the glue has high deformation recovery, mechanical and self-sealing properties.

[0035] (2) The present application uses a modified alumina / titanium oxide composite two-phase structure, and polyvinylpyrrolidone and sodium alginate are used as surface treatment agents to modify alumina, which improves the interaction effect between the base material and the inorganic phase, and the two-phase system promotes the dispersion of the filler in the matrix, significantly improves the mechanical properties of the sealant, and also has a gain effect on the self-sealing property of the material.

[0036] (3) The self-sealing glue of the present application can be applied in multiple ways, on the one hand, it can be sprayed on the inner wall of the tire, and has high adhesion between the tire air-tight layer, without any damage to the inner wall of the tire, only the inner wall of the tire is cleaned and dried; on the other hand, it can be compounded with the transition layer and vulcanized with the tire blank, so that the self-sealing material is formed in the blank, and the performance of the tire is not affected; both can achieve good effect of preventing sharp objects such as screws from being pierced, avoid tire blowout and improve driving safety. BRIEF DESCRIPTION OF DRAWINGS

[0037] Fig. 1 The elongation retention rate of the self-sealing glue material prepared in the examples and comparative examples of the present application after high / low temperature treatment.

[0038] Fig. 2 The adhesion retention rate of the self-sealing rubber material prepared in the examples and comparative examples of the present application after high / low temperature treatment. DETAILED DESCRIPTION

[0039] The technical solutions of the present application will be clearly and completely described below in combination with the examples of the present application. Obviously, the described examples are only some of the examples of the present application, but not all the examples. Based on the examples in the present application, all the other examples obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0040] The test methods used in the examples of the present application are all conventional methods unless otherwise specified. The materials and reagents used are all commercially available unless otherwise specified. The reagent Polyvest EP ST-E 60 (Yingchuang) (hereinafter referred to as ST-E60) involved in the examples and comparative examples of the present application is purchased from Shanghai Zhuyu Industry and Trade Co., Ltd. and the hydroxyl-terminated polybutadiene is purchased from Wuhan Huaxiang Kejie Biological Technology Co., Ltd.

[0041] The biphase filler used in the examples of the present application is modified nano-alumina / titanium oxide, which is prepared by the following method: 45 parts of nano-alumina, 3 parts of modifier polyvinylpyrrolidone and sodium alginate are added into 140 parts of aqueous solution, the mass ratio of polyvinylpyrrolidone and sodium alginate is 4:1, ultrasonic treatment is carried out at room temperature for 20 min, stirring is carried out at 60℃ for 30 min, then the modified nano-alumina is obtained by washing the dried solid with ethanol solution, the modified nano-alumina is dispersed in toluene at a concentration of 0.08 g / mL, ultrasonic dispersion is carried out for 30 min; acetic acid and triethanolamine are mixed and stirred for 30 min, then tetrabutyl titanate is added into the reactor and stirred for 30 min to obtain a mixed solution, then the toluene dispersion solution of nano-alumina is slowly added into the mixed solution, and stirring is continued for 2 h to obtain a sol, the sol is aged at room temperature for 10 h, then dried in an oven at 80℃, then ethanol is added, and ball milling is carried out at a rotation speed of 500 r / min for 4 h, and then dried at 80℃, to obtain the modified nano-alumina / titanium oxide biphase filler; wherein the volume amount ratio of acetic acid, triethanolamine, tetrabutyl titanate and nano-alumina dispersion solution is 36.0 mL:3 mL:7 mL:25 mL. In order to reduce the sample test error, the biphase fillers used in each example and comparative example are prepared under the same conditions.

[0042] Example 1

[0043] A self-sealing rubber material of a safety tire, comprising the following components in parts by weight:

[0044] Butyl rubber 35 parts, ethylene propylene diene rubber 35 parts, ST-E60 5.8 parts, modified nano-alumina / titanium oxide dual-phase composite filler 20 parts, zinc stearate 2.4 parts, epoxy soybean oil 1.2 parts, diatomite 3.5 parts, polyvinyl alcohol 1.6 parts, antioxidant RD 0.4 parts, antioxidant 4010NA 0.4 parts, antioxidant ODA 0.4 parts, carbon black 0.8 parts.

[0045] A preparation process of a self-sealing glue of a safety tire:

[0046] 1) According to the above formula amount, blend butyl rubber, ethylene propylene diene rubber, ST-E60, antioxidant, set the temperature to 110℃, and stir and mix for 30 min;

[0047] 2) Add dual-phase filler, zinc stearate, epoxy soybean oil, diatomite, and polyvinyl alcohol, continue to heat to 150℃, and stir for 3h;

[0048] 3) Add carbon black, heat to 210℃, stir for 1.5h, and vacuum to eliminate bubbles.

[0049] Example 2

[0050] A self-sealing glue of a safety tire, comprising the following components in parts by weight:

[0051] Butyl rubber 26 parts, ethylene propylene diene rubber 39 parts, ST-E60 4.5 parts, modified nano-alumina / titanium oxide dual-phase composite filler 18 parts, zinc stearate 2.0 parts, epoxy soybean oil 0.8 parts, diatomite 4.5 parts, polyvinyl alcohol 2.0 parts, antioxidant 4020 0.4 parts, antioxidant MB 0.4 parts, carbon black 1.2 parts.

[0052] A preparation process of a self-sealing glue of a safety tire:

[0053] 1) According to the above formula amount, blend butyl rubber, ethylene propylene diene rubber, ST-E60, antioxidant, set the temperature to 120℃, and stir and mix for 25 min;

[0054] 2) Add dual-phase filler, zinc stearate, epoxy soybean oil, diatomite, and polyvinyl alcohol, continue to heat to 130℃, and stir for 2h;

[0055] 3) Add carbon black, heat to 200℃, stir for 2h, and vacuum to eliminate bubbles.

[0056] Example 3

[0057] A self-sealing glue of a safety tire, comprising the following components in parts by weight:

[0058] Butyl rubber 45 parts, ethylene propylene diene rubber 30 parts, ST-E60 6.5 parts, modified nano-alumina / titanium oxide dual-phase composite filler 25 parts, zinc stearate 3.0 parts, epoxy soybean oil 1.0 part, diatomite 4.0 parts, polyvinyl alcohol 1.4 parts, antioxidant 445 0.5 parts, antioxidant MB 0.5, carbon black 0.5 parts.

[0059] A preparation process of a self-sealing glue of a safety tire:

[0060] 1) According to the above formula amount, blend butyl rubber, ethylene propylene diene rubber, ST-E60, antioxidant, set the temperature to 80℃, and stir and mix for 40 min;

[0061] 2) Add dual-phase filler, zinc stearate, epoxy soybean oil, diatomite, and polyvinyl alcohol, continue to heat to 120℃, and stir for 3h;

[0062] 3) Add carbon black, heat to 180℃, stir for 3h, and vacuum to eliminate bubbles.

[0063] Example 4

[0064] A self-sealing glue of a safety tire, comprising the following components in parts by weight:

[0065] Butyl rubber 30 parts, ethylene propylene diene rubber 30 parts, ST-E60 4.0 parts, modified nano-alumina / titanium oxide dual-phase composite filler 16 parts, zinc stearate 1.0 part, epoxy soybean oil 1.5 parts, diatomite 3.5 parts, polyvinyl alcohol 1.0 part, antioxidant RD 0.5 part, antioxidant 4010NA 0.5 part, antioxidant ODA 0.5 part, carbon black 0.3 part.

[0066] A preparation process of a self-sealing glue of a safety tire:

[0067] 1) According to the above formula amount, blend butyl rubber, ethylene propylene diene rubber, ST-E60, antioxidant, set the temperature to 110℃, and stir and mix for 30 min;

[0068] 2) Add dual-phase filler, zinc stearate, epoxy soybean oil, diatomite, and polyvinyl alcohol, continue to heat to 150℃, and stir for 2h;

[0069] 3) Add carbon black, heat to 200℃, stir for 2h, and vacuum to eliminate bubbles.

[0070] Example 5

[0071] A self-sealing glue of a safety tire, comprising the following components in parts by weight:

[0072] Butyl rubber 29 parts, ethylene propylene diene rubber 29 parts, ST-E60 5.5 parts, modified nano-alumina / titanium oxide dual-phase composite filler 23 parts, zinc stearate 2.0 parts, epoxy soybean oil 1.0 part, diatomite 3.0 parts, polyvinyl alcohol 0.8 parts, antioxidant RD 0.2 parts, antioxidant 4010NA 0.2 parts, carbon black 0.8 parts.

[0073] A preparation process and use method of a self-sealing glue of a safety tire:

[0074] 1) According to the above formula, butyl rubber, ethylene propylene diene rubber, ST-E60, antioxidant are blended, the temperature is set to 110°C, and stirring is mixed for 30 min;

[0075] 2) Add dual-phase filler, zinc stearate, epoxy soybean oil, diatomite, polyvinyl alcohol, continue to heat to 150°C and stir for 3h;

[0076] 3) Add carbon black, heat to 220°C, stir for 1.5h, and vacuum to eliminate bubbles.

[0077] Comparative Example 1

[0078] The difference from Example 1 is that the tackifier in the rubber component is replaced by hydroxyl-terminated polybutadiene (same amount), and the other components, amounts, and self-sealing glue preparation process are the same as Example 1, which will not be repeated here.

[0079] Comparative Example 2

[0080] The difference from Example 1 is that the heat stabilizer in the rubber component is replaced by a composite of calcium stearate and zinc stearate instead of zinc stearate and epoxy soybean oil (calcium stearate is used in the same amount as epoxy soybean oil), and the other components, amounts, and self-sealing glue preparation process are the same as Example 1, which will not be repeated here.

[0081] Comparative Example 3

[0082] The difference from Example 1 is that the dual-phase filler in the rubber component is directly added without modification, and the amount of unmodified nano-alumina and titanium dioxide particles is the same as the amount of modified nano-alumina (40 parts) and titanium oxide (7ml tetrabutyl titanate hydrolyzed under the same conditions) in the modified nano-alumina / titanium oxide dual-phase composite of Example 1, and the other components, amounts, and self-sealing glue preparation process are the same as Example 1, which will not be repeated here.

[0083] Comparative Example 4

[0084] The difference from Example 1 is that the dual-phase filler in the rubber component is directly added modified nano-alumina (only surface treated with polyvinylpyrrolidone and sodium alginate) and titanium dioxide particles (20 parts of the same amount of modified nano-alumina and titanium oxide (7 ml of tetrabutyl titanate hydrolyzed under the same conditions) are mixed and replaced), and other components, amounts and self-sealing glue preparation process are the same as Example 1, which will not be repeated here.

[0085] Comparative Example 5

[0086] The difference from Example 1 is that the rubber component lacks the auxiliary diatomite, and other components, amounts and self-sealing glue preparation process are the same as Example 1, which will not be repeated here.

[0087] Comparative Example 6

[0088] The difference from Example 1 is that the rubber component is completely the same, but the process for preparing the self-sealing glue adopts one-step mixing, blending all components of the formulation amount, heating to 210°C, stirring for 5h, and vacuuming to eliminate bubbles.

[0089] The self-sealing glue materials obtained in each example and comparative example are tested, and the tests include the following contents:

[0090] Detection method

[0091] 1. Elongation at break: The elongation at break is tested according to GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", the testing machine is operated at a moving speed of 500 mm / min (tensile rate), the laboratory temperature is 27°C, and the relative humidity is 65%.

[0092] 2. Resilience: The resilience is tested according to GB1681-2009 "Determination of resilience of vulcanized rubber".

[0093] 3. Bonding performance: The prepared self-sealing glue sample is melted at 210°C, and the self-sealing glue is uniformly sprayed on the inner surface of the tire by a spraying device, with a thickness of 4mm. After cooling, the DCS-500 universal testing machine is used to peel off and test the adhesion.

[0094] 4. Low / high temperature resistance: The prepared rubber and tire are respectively placed at -45°C or 120°C for 48h, and the elongation at break and adhesion are tested according to methods 1 and 3, and the retention rate is used to evaluate the low / high temperature resistance; the rubber is extruded into a 5mm thick, 35mm wide and 200mm long rubber strip, which is placed in a low temperature of -45°C for 12h, and a folding mechanism is used to fold the rubber strip from 180° to 35° for 200 times, and whether cracks appear at the bending part of the rubber strip is observed.

[0095] 5. Self-sealing performance: according to GB / T38510-2020, use a tire puncture device to puncture the tire, test whether the tire leaks after being punctured, (1) leak observation table method: foam water is sprayed on the wound, if there is a leak, foam will be produced, the more serious the leak, the more foam produced. (2) Tire pressure measurement: after the tire is punctured with a 8mm diameter screw and pulled out, 24h interval, then repeat the puncture 3 times at the same position and measure the pressure. (3) The self-sealing tire coated with a thickness of 4mm is inflated to standard pressure, then treated at-45℃ or 120℃ for 24h, then immediately punctured with a screw, and the foam water test is carried out before and after the screw is pulled out, to observe whether there is air bubble around the screw and the pulling point.

[0096] Test result analysis

[0097] The test results of the elongation at break, resilience and adhesion of the self-sealing adhesive are shown in Table 1.

[0098] Table 1

[0099]

[0100]

[0101] From Table 1 and Figs. 1-2 It can be seen that the prepared adhesive has excellent mechanical properties and thermal stability, and the elongation at break and adhesion retention rate after high and low temperature treatment can reach more than 95%, with small decrease, indicating that the self-sealing adhesive prepared in the application can withstand high and low temperature environment in actual use, avoiding the performance decline caused by high temperature of the tire, and no brittle fracture occurs after low temperature treatment.

[0102] In Comparative Example 1, the properties of the adhesive after replacing ST-E 60 with hydroxyl-terminated polybutadiene are reduced, which may be due to the fact that the polybutadiene terminated with triethoxysilane has lower surface energy and high penetration force, effectively improving the wetting and dispersion of fillers and inorganic materials in the polymer, thereby enhancing the adhesion of the adhesive to the substrate. At the same time, it forms a network structure connected by polyene long chains with Si-O-Si bonds as crosslinking points. This system not only has excellent weather resistance, aging resistance and durability, but also can effectively inhibit and avoid the generation of surface cracks of the sealing adhesive after long-term use.

[0103] Compared with the use of zinc stearate and calcium stearate as a thermal stabilizer in Comparative Example 2, the use of zinc stearate and epoxy soybean oil can improve the thermal stability of the adhesive, and the zinc stearate can promote the ring-opening crosslinking of the epoxy soybean oil, and has a better synergistic effect on the mechanical properties and high and low temperature resistance of the adhesive.

[0104] The fillers used in Comparative Examples 3 and 4, modified or unmodified nano-alumina and titanium dioxide particles, have reduced network structure and do not form firm filler-rubber bonding, which significantly reduces the mechanical properties of the rubber compound; at the same time, poor compatibility and dispersion between the filler and the base material easily cause the brittleness of the sealant to increase, affecting the low-temperature performance and reducing the crack resistance.

[0105] Comparative Example 5 lacks the siliceous earth component compared to Example 1, and the use of the siliceous earth component in the example can reduce the moisture in the sealant, making the heat stabilizer more stable and / or the heat stabilizer capturing free active groups more stable, further enhancing the heat stability of the sealant, so that the sealant has excellent high and low temperature resistance.

[0106] Comparative Example 6 uses a traditional one-step mixing method to prepare the rubber compound, which reduces the dispersion and compatibility between the components, and the performance of the rubber compound is generally lower than that of Example 1.

[0107] Application Example

[0108] The self-sealing sealant prepared in the present application can be prepared into a safety self-sealing tire in the following two ways:

[0109] 1. After the inside of the tire is cleaned and dried, the prepared self-sealing sealant is heated to 210°C for melting treatment, and the self-sealing sealant is uniformly sprayed on the inner surface of the tire with a spraying device, with a thickness of 4 mm.

[0110] 2. The sealant is melted at 210°C and then placed in a roll extruder for calendering to form a 4 mm thick sheet, one side of which is protected by a high-temperature resistant release film, and the other side is laminated and pressed with a transition layer rubber to form a 4.5 mm thick rubber strip. Then, the other side of the transition layer is attached to the inner side of the innermost airtight layer of the tire, the rubber strip is positioned on the tire blank, and a 42 KPa pressure is applied for rotary lamination and compaction. After trimming, the release agent is uniformly coated on the surface of the rubber strip on the capsule and the tire blank, and low-pressure shaping is performed. The vulcanization is carried out at a temperature of 160°C for 45 minutes, and after vulcanization, the inner high-temperature resistant release film is removed, and an integrally vulcanized safety self-sealing tire is obtained.

[0111] The transition layer rubber is composed of 5 parts of butyl rubber and 10 parts of natural rubber, 15 parts of EVA, 15 parts of C5 resin, 12 parts of dioctyl sebacate (DOS), 5 parts of calcium carbonate, 2 parts of kaolin, 2 parts of carbon black, and 1.5 parts of antioxidant 2246. After heating and stirring in a reaction kettle at 220°C for 6 hours, the material is discharged and coated as a 0.5-1 mm thick rubber strip, and the two sides are pasted with release film for use.

[0112] The sealant obtained from the examples 1-3 and the comparative examples of the present application is sprayed on the inner surface of the tire by way 1; the sealant prepared in the examples 4-5 is vulcanized by way 2 after positioning the embryo, and the performance detection results are shown in Table 2.

[0113] Table 2

[0114]

[0115]

[0116] Note: The amount of foam indicates the order of self-sealing performance from strong to weak as follows: no foam > trace > small amount > more > large amount.

[0117] From Table 2, it can be seen that the tire prepared by the sealant of the present application does not appear foam after spraying the foamed water on the damaged tire, which indicates that the tire does not leak air and has good self-sealing performance. From the pressure detection results in Table 2, it can be seen that the air pressure of the tire prepared by the present application does not change significantly after being punctured and pulled out, and no sealant flows out at the moment when the nail is pulled out, which indicates that the sealant can quickly recover and achieve self-sealing. The tire does not leak air after repeated puncture, and has good sealing stability. The foaming test after high and low temperature treatment also proves that the self-sealing tire prepared by the present application has good temperature resistance, which meets the demand of tire puncture prevention and self-sealing in different seasons or regions with large temperature difference.

[0118] Obviously, the above examples of the present application are only examples for clearly illustrating the technical solutions of the present application, and are not the limitation of the specific embodiments of the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the claims of the present application should be included in the protection scope of the claims of the present application.

Claims

1. A self-sealing rubber composition for a safety tire, characterized by, The self-sealing adhesive is prepared from the adhesive composition of any one of claims 1-6, and the preparation process comprises the following steps: The modified nano-alumina / titanium oxide dual-phase composite is prepared by the following method: nano-alumina is modified with polyvinylpyrrolidone and sodium alginate as surface treatment agents, and then dispersed in toluene; acetic acid, triethanolamine are mixed, and tetrabutyl titanate is added and stirred to obtain a mixed solution, then the toluene dispersion of modified nano-alumina is added to the mixed solution, and the sol is obtained by continuing to stir, and the sol is aged and dried, and then ground to obtain the modified nano-alumina / titanium oxide dual-phase composite.

2. The composition of claim 1, wherein, The components are as follows in terms of weight parts: 58-75 parts of the base material, 4.0-6.5 parts of the tackifier, 16-25 parts of the inorganic filler, 2.3-4.0 parts of the heat stabilizer, 3.0-4.5 parts of the auxiliary agent, 0.8-2.0 parts of the dispersant, 0.2-1.5 parts of the antioxidant, and 0.3-1.2 parts of the colorant.

3. The composition of claim 1, wherein, The weight ratio of butyl rubber to ethylene-propylene-diene rubber in the base material is 2:3-3:

2.

4. The composition of claim 1, wherein, The tackifier is silane-terminated modified polybutadiene rubber; the silane-terminated modified polybutadiene rubber comprises triethoxysilane-terminated modified polybutadiene selected from one of Polyvest EP ST-E 60 and Polyvest EP ST-E 100.

5. The composition of claim 1, wherein, The weight ratio of zinc stearate to epoxy soybean oil in the heat stabilizer is 2-5:1-3.

6. The composition of claim 1, wherein, The auxiliary agent is diatomite or bentonite; the dispersant is polyvinyl alcohol; the antioxidant is two or more of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine, 2-mercaptobenzimidazole, 4,4'-bis(dimethylbenzyl) diphenylamine, 4,4'-dioctyl diphenylamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and N-phenyl-N'-isopropyl-p-phenylenediamine antioxidant; and the colorant is carbon black or graphite powder.

7. A process for the preparation of a self-sealing gum for a safety tire, characterized in that, The self-sealing adhesive is prepared from the adhesive composition of any one of claims 1-6, and the preparation process comprises the following steps: S1, blending the base material, the tackifier, and the antioxidant, setting the temperature to 80-120℃, and stirring uniformly to obtain a mixture; S2, adding the inorganic filler, the heat stabilizer, the auxiliary agent, and the dispersant to the mixture, continuing to heat to 120-150℃, and stirring for a period of time; S3, adding the colorant, heating to 180-220℃, stirring uniformly, and vacuumizing to eliminate bubbles, thereby obtaining the self-sealing adhesive.

8. Use of a self-sealing glue in the preparation of a self-sealing safety tire, characterized in that, The self-sealing adhesive is obtained by the preparation process of claim 7, and the application is that the self-sealing adhesive is uniformly sprayed on the inner surface of the tire after being treated by melting.

9. An integrally vulcanized self-sealing safety tire characterized by, The self-sealing adhesive obtained by the preparation process of claim 7 is melted and placed in a roll extruder for calendering, laminated and pressed with a transition layer adhesive to form a rubber strip, and then the rubber strip is positioned inside the tire embryo, rotationally laminated and compacted, and then vulcanized together with the tire embryo after tire molding to obtain the tire.

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