High-temperature-resistant aircraft tire tread rubber, preparation method thereof and aircraft tire

Abstract

The invention discloses high-temperature-resistant aircraft tire tread rubber and a preparation method and application thereof, and the tread rubber is prepared from the following raw materials in parts by weight: 40-50 parts of natural rubber, 50-60 parts of butadiene styrene rubber, 50-75 parts of a reinforcing system, 5-10 parts of a heat-resistant system, 6-12 parts of an anti-aging system, 2-5 parts of a vulcanization system and 2-5 parts of other auxiliaries. The reinforcing system comprises white carbon black, a coupling agent and a white carbon black dispersing agent in a weight ratio of (50-60): (3-5): (5-6); the heat-resistant system comprises nano aluminum powder and nano titanium dioxide in a weight ratio of (3-5): (3-4); after the tread rubber is subjected to hot air aging at 150 DEG C for 4 hours, the increase amount of the Shore A type hardness is 5% or below, the increase amount of 300% stress at definite elongation is 10% or below, the reduction amount of the tensile strength is 25% or below, and the reduction amount of the elongation at break is 25% or below. The tread rubber can ensure the stability and long-term reliability of the aircraft tire under the high-temperature use condition.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft tires, and in particular to a high-temperature resistant aircraft tire tread rubber and a preparation method thereof, and an aircraft tire. Background Art

[0002] During takeoff and landing, the tire tread must withstand a high temperature air environment of more than 150°C. Especially during takeoff and landing, the heat generated by friction and compression of the tire tread rubber will cause the local temperature to rise significantly. High temperature not only accelerates the aging of the rubber and reduces the performance of the tire, but may also cause the rubber to soften and fall off, thereby affecting the service life of the tire and flight safety. Therefore, the tread rubber is required to have excellent high temperature resistance and aging resistance to ensure that it can maintain stable performance in extreme temperature environments. However, the existing aircraft tire tread rubber mostly adopts the traditional formula of natural rubber and styrene-butadiene rubber. Although these materials have certain heat resistance, in a high temperature environment of 150°C, the rubber often shows obvious performance degradation after long-term use, such as increased hardness, decreased tensile strength, and even problems such as rubber falling off or tread detachment.

[0003] In the prior art, many studies have improved the thermal stability and durability of rubber by adding high temperature resistant materials or anti-aging agents. Common improvement methods include adding fillers such as white carbon black and anti-aging agents to improve the mechanical strength and anti-aging properties of the rubber. Although these methods have improved the thermal stability of the rubber to a certain extent, they still have some shortcomings, especially in the control of the temperature rise of the rubber. Existing rubbers are often unable to effectively avoid heat accumulation in high temperature environments, resulting in excessively high temperatures of the rubber, which in turn affects its performance and safety. Due to the continuous accumulation of heat generated by the rubber in a high temperature environment, the prior art has failed to provide a complete solution that can both effectively resist high temperatures and control heat accumulation.

[0004] For example, invention CN116769236A discloses an aviation radial tire tread rubber material, which uses raw materials such as super-polymerized natural rubber, super-wear-resistant carbon black and multifunctional cross-linking agent to improve the mechanical properties and wear resistance of the rubber material. The invention shows high tensile strength, elongation at break, good tear resistance, low dynamic heat generation and good heat resistance stability. However, despite its advantages in mechanical properties and wear resistance, its long-term stability in high temperature environments is still limited, and it has not fully considered how to further improve high temperature resistance by optimizing thermal management to control the temperature rise of the rubber material.

[0005] Similarly, the invention CN117106240A discloses a tread base rubber with good heat resistance and wear resistance, and its preparation method and application. The tread base rubber is mainly made of N234 carbon black wet rubber, and is matched with auxiliary materials such as super vulcanizer, nano zinc oxide, tear-resistant resin, antioxidant, insoluble sulfur, anti-vulcanization reversion agent SL-9088, and silane coupling agent. It has low dynamic heat generation, good heat resistance, high tensile strength, tear strength and elongation at break, and good wear resistance, high rebound value, and high bonding strength with the cord layer. The invention particularly emphasizes the control of dynamic heat generation, and to a certain extent improves the thermal stability and wear resistance of the rubber material. However, due to the problem of heat accumulation of the rubber material, long-term exposure to high temperature environment may still cause the performance of the rubber material to decline. Especially when the aircraft takes off and lands, the heat generated by friction and compression of the tread rubber material may accumulate too quickly, and there is still a risk of tire stability and safety.

[0006] Therefore, how to provide an aircraft tire tread rubber that can effectively resist high temperatures, effectively control heat accumulation, and have excellent comprehensive performance, so that the aircraft tire can still maintain stable performance in extreme temperature environments and extend its service life to ensure flight safety, is an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0007] In view of the defects existing in the above-mentioned prior art, the present invention provides a high-temperature resistant aircraft tire tread rubber, a preparation method thereof, and an aircraft tire. By optimizing the material composition and ratio, combining a reinforcement system, a heat reflective material, and a low heat generation formula, the tread rubber and the aircraft tire including the tread rubber can effectively resist high temperature, control heat accumulation, and significantly reduce the unexpected temperature rise of the rubber in a high temperature environment, while maintaining excellent mechanical properties and aging resistance, thereby ensuring the stability and long-term reliability of the tire under high temperature use conditions.

[0008] In a first aspect, the present invention provides a high temperature resistant aircraft tire tread rubber, wherein the tread rubber raw materials, measured in parts by weight, include:

[0009] Natural rubber 40-50 parts

[0010] Styrene butadiene rubber 50-60 parts

[0011] Reinforcement system 50-75 parts

[0012] Heat resistant system 5-10 parts

[0013] Anti-aging system 6-12 parts

[0014] Vulcanization system 2-5 parts

[0015] Other additives 2-5 parts;

[0016] The reinforcing system comprises white carbon black, a coupling agent and a white carbon black dispersant, and the weight ratio of the white carbon black, the coupling agent and the white carbon black dispersant is (50-60):(5-6):(3-5);

[0017] The heat-resistant system includes nano-aluminum powder and nano-titanium dioxide, and the weight ratio of the nano-aluminum powder to the nano-titanium dioxide is (3-5):(3-4).

[0018] The present invention adopts a special reinforcement system, a heat-resistant system and other comprehensive formulas to obtain a silver-gray tread rubber. On the basis of having good mechanical properties, the tread rubber has a light color and has a reflective function for the heat in the air, is not easy to absorb heat, and effectively improves the high temperature resistance of the tread rubber. In the existing aircraft tire tread rubber, the thermal stability and durability of the rubber are generally improved by adding high temperature resistant materials or anti-aging agents, but the performance is significantly reduced after 150°C high temperature, and the tread rubber falls off or even throws off the tread. After the high temperature resistant aircraft tire tread rubber of the present invention is aged in hot air at 150°C×4h, the increase in Shore A hardness is less than 5%, the increase in 300% elongation stress is less than 10%, the increase in compression fatigue heat generation is less than 25%, the increase in wear loss is less than 35%, the decrease in tensile strength is less than 25%, the decrease in elongation at break is less than 25%, and the decrease in tear strength is less than 25%, which can meet the aircraft use requirements for a longer time and stably.

[0019] Preferably, the anti-aging system comprises p-phenylenediamine antioxidant, ketoamine antioxidant and protective wax, and the weight ratio of p-phenylenediamine antioxidant, ketoamine antioxidant and protective wax is (2-3):(2-3):(2-4).

[0020] Preferably, the p-phenylenediamine antioxidant includes: at least one of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-N'-diphenyl-p-phenylenediamine and 4,4-bis(2,2-dimethylbenzyl)diphenylamine;

[0021] The ketoamine antioxidant includes at least one of diphenylaminoacetone, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline;

[0022] The protective wax includes at least one of Okerin1900 and RW590.

[0023] More preferably, the p-phenylenediamine antioxidant is N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, the ketoamine antioxidant is diphenylaminoacetone, and the protective wax is Okerin1900.

[0024] Preferably, the vulcanization system comprises a vulcanizing agent, a vulcanization accelerator and a scorch retarder, and the weight ratio of the vulcanizing agent, the vulcanization accelerator and the scorch retarder is (15-25):(10-20):(1-2).

[0025] Preferably, the other auxiliary agents include an active agent, the active agent includes zinc oxide and stearic acid, and the weight ratio of zinc oxide to stearic acid is (5-8):(2-3).

[0026] Preferably, part of the white carbon black is modified by a coupling agent and then premixed with the styrene-butadiene rubber to obtain modified styrene-butadiene rubber. The mass ratio of the white carbon black to the styrene-butadiene rubber is preferably (45-60): (50-60).

[0027] The coupling agent can be a silane coupling agent commonly used in the art, such as γ-aminopropyltriethoxysilane (silane coupling agent KH550), (3-epoxypropoxy)propyltrimethoxysilane (silane coupling agent KH560), etc., which is beneficial to improving the interface connection performance between silica and the rubber matrix and the dispersibility of silica in the rubber matrix.

[0028] In addition, it is more preferred to use a mercaptosilane coupling agent to hydrophobize the white carbon black, and further react with an oxidant to oxidize the mercapto group to form a disulfide bond. The white carbon black modified in this way can not only improve the bonding ability with the base rubber, but also has sufficient burning safety when it is matched with a rubber product that needs to be vulcanized. The mercaptosilane coupling agent can be selected from 3-mercaptopropyltrimethoxysilane or 3-mercaptopropylmethyldimethoxysilane. The oxidant can be selected from at least one of the oxidants commonly used in the art such as hydrogen peroxide, organic peroxide, hypochlorite, perborate, permanganate, bromine, nitric oxide, etc.

[0029] Preferably, the heat-resistant system satisfies at least one of the following conditions:

[0030] (1) The size of nano titanium dioxide is 15-100nm, and the BET specific surface area is 10-200m 2 / g;

[0031] (2) The specific gravity of nano aluminum powder is 2.3-3.1g / cm 3 , particle size is 100-300nm;

[0032] (3) The heat-resistant system is premixed with at least a portion of the natural rubber.

[0033] The present invention adopts nano titanium dioxide and nano aluminum powder. Nano titanium dioxide has dyeing and coloring effects, making the rubber light-colored; nano aluminum powder, also known as silver powder, has good reflective effects on light and heat. Adding nano aluminum powder to the rubber can prevent the rubber from quickly absorbing heat and heating up in a high-temperature environment, thereby reducing the temperature of the rubber and effectively improving the high-temperature resistance of the tread rubber.

[0034] Specifically, the nano titanium dioxide is preferably rutile titanium dioxide, which is white loose powder, has a rutile content of more than 99.8%, and when the size and BET specific surface area meet the above range, the dispersibility of the nano titanium dioxide in the rubber matrix can be effectively improved. In addition, the nano titanium dioxide also has good hydrophilicity, which is beneficial to improving the wet grip performance of the tire.

[0035] The addition of nano aluminum powder is not only beneficial to improving the high temperature resistance of the tread rubber, but also to improving the ozone resistance. However, the addition amount and physical parameters of nano aluminum powder and nano titanium dioxide also need to be strictly controlled. If the amount is too low, it is difficult to show the above advantages. If the amount is too high, it is easy to cause deformation of the molded product due to the swelling phenomenon of the raw rubber matrix. Moreover, when the particle size is too large or too small, it is not conducive to dispersion in the rubber matrix. In addition, in order to improve the dispersion uniformity and compatibility, the heat-resistant system can also be pretreated with a coupling agent.

[0036] From the structure and the results of thermal oxidation degradation tests, there is a side methyl group on the main chain of natural rubber that is very easy to rearrange, which leads to its insufficient thermal stability in an environment above 70°C. The present invention premixes the heat-resistant system with at least part of the natural rubber to extend the action time of the heat-resistant system and the natural rubber, improve the bonding degree and dispersibility of the heat-resistant system and the natural rubber, and can better make up for the defect of insufficient heat resistance of natural rubber. Specifically, for example, more than 20%, preferably more than 50% of the natural rubber is premixed with the heat-resistant system after being heated to 90-120°C, and the heat-resistant system is slowly added to the natural rubber in steps for premixing under high-speed shear (for example, the shear rate of high-speed shear is 2000-5000r / min).

[0037] In a second aspect, the present invention further provides a method for preparing the high temperature resistant aviation tire tread rubber, comprising the following steps:

[0038] S1, first stage mixing:

[0039] The natural rubber, styrene-butadiene rubber, the reinforcement system, the heat-resistant system, the anti-aging system and other additives are mixed and kneaded in proportion to obtain a first-stage mixed rubber;

[0040] S2, two-stage mixing:

[0041] 2.1 After the first stage mixed rubber is left for 10h to 30h, the vulcanization system is added and mixed and kneaded to the second stage discharge temperature;

[0042] 2.2 The second-stage mixture is discharged and sheeted, and cooled to obtain the final tread rubber.

[0043] The present invention can adopt a common mixing and kneading method to obtain the rubber composition, but it is more preferred to adopt a batch mixing and pre-treatment synergistic method to obtain the mixed rubber and the final tread rubber.

[0044] Preferably, the step S1 specifically includes:

[0045] 1.1 Mix natural rubber and styrene-butadiene rubber in proportion and knead them;

[0046] 1.2 Add the reinforcement system into the mixed kneading according to the proportion;

[0047] 1.3 Add heat-resistant system, anti-aging system and other additives according to proportion and mix;

[0048] 1.4 When the mixing temperature reaches the first discharging temperature, discharge a section of the mixture and press it into sheets, then cool it to obtain a first section of mixed rubber.

[0049] On this basis, the preparation method must also meet at least one of the following conditions:

[0050] In step 1.1, the mixing and kneading temperature is increased from 80-90°C to 90-105°C;

[0051] In step 1.2, the mixing and kneading temperature is increased from 90-105°C to 125-135°C;

[0052] In step 1.3, the temperature of the mixing and kneading is increased from 125-135°C to 135-145°C;

[0053] In step 1.4, the discharge temperature of the first stage is 135-145°C;

[0054] In step 2.1, the second stage discharge temperature is 95-105°C.

[0055] More preferably, before step S1, part of the white carbon black is modified by a coupling agent and then premixed with the styrene-butadiene rubber to obtain modified styrene-butadiene rubber, which comprises the following steps:

[0056] Step 1: Grind a slurry of silica with a solid content of 15-30wt% for 5-15 minutes;

[0057] Step 2: Add mercaptosilane coupling agent and continue grinding for 10-30 minutes;

[0058] Step 3: Add an oxidant and continue grinding for 10-60 minutes to obtain a modified silica slurry;

[0059] Step 4: Mix the styrene-butadiene rubber latex and the modified silica slurry by high-speed collision to achieve instant coagulation of the silica slurry and the latex to obtain the modified styrene-butadiene rubber.

[0060] After obtaining the modified styrene-butadiene rubber, the modified styrene-butadiene rubber can be produced according to the aforementioned mixing and kneading method, including:

[0061] 1.1 Mix natural rubber and modified styrene-butadiene rubber in proportion and knead them;

[0062] 1.2 Add the remaining reinforcement system into the mixing and kneading;

[0063] 1.3 Add heat-resistant system, anti-aging system and other additives according to proportion and mix;

[0064] 1.4 When the mixing temperature reaches the first discharging temperature, discharge a section of the mixture and press it into sheets, then cool it to obtain a first section of mixed rubber.

[0065] In addition, after the heat-resistant system is premixed with at least part of the natural rubber, the production can also be carried out according to the aforementioned mixing and kneading method, including:

[0066] 1.0 Heat at least part of the natural rubber to 90-120°C, and slowly add the heat-resistant system to the natural rubber in steps for premixing at a high shear rate of 2000-5000 r / min;

[0067] 1.1 Mix and knead the premixed natural rubber (or the premixed natural rubber and untreated natural rubber) and styrene-butadiene rubber (or modified styrene-butadiene rubber) in proportion;

[0068] 1.2 Add the reinforcement system (or the remaining reinforcement system) to the mixing and kneading;

[0069] 1.3 Add the anti-aging system and other additives in proportion and mix them;

[0070] 1.4 When the mixing temperature reaches the first discharging temperature, discharge a section of the mixture and press it into sheets, then cool it to obtain a first section of mixed rubber.

[0071] Through the reinforcement pretreatment of styrene-butadiene rubber and / or the heat-resistant premixing treatment of natural rubber, targeted grouping pretreatment is carried out according to the colloid characteristics of styrene-butadiene rubber and natural rubber, so as to improve the targeting of the synergistic components, reduce the overall defect risk of the tread rubber, and better improve the comprehensive properties of the tread rubber such as heat resistance and mechanical properties.

[0072] In a third aspect, according to the excellent performance and ideal application scenarios of the tread rubber, the present invention also provides an aircraft tire, comprising the high temperature resistant aircraft tire tread rubber or the high temperature resistant aircraft tire tread rubber obtained by the preparation method.

[0073] The present invention has at least the following beneficial effects:

[0074] (1) The present invention not only significantly improves the tensile strength and tear strength of the rubber material, but also effectively reduces the compression heat generation performance of the material through the reasonable combination of natural rubber and styrene-butadiene rubber, and the reinforcement system containing white carbon black. The high reinforcement performance and low heat generation characteristics of white carbon black complement the heat resistance of styrene-butadiene rubber, greatly reducing the heat accumulation problem of aviation tires when running under high load and high speed. This optimized design ensures the continuous performance of the tire under high temperature conditions, while reducing the risk of tread failure caused by temperature rise and improving operational safety.

[0075] (2) The present invention optimizes the formula, introduces a heat-resistant system composed of nano titanium dioxide and nano aluminum powder as the core, and utilizes its excellent heat reflection performance to significantly reduce the heat absorption and temperature rise rate of the rubber in a high-temperature environment, thereby greatly improving the thermal stability of the tread rubber. After hot air aging, it can maintain good mechanical properties and effectively avoid the problem of tread rubber cracking, falling off, and even tread throwing in a high-temperature environment. This design meets the special requirements of aviation tires under harsh working conditions such as aircraft takeoff and landing, and ensures the safety and stability of use under high-temperature conditions. DETAILED DESCRIPTION

[0076] In order to better understand the above technical solution, the above technical solution will be described in detail below in combination with the specification and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0077] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0078] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0079] An aircraft tire, comprising a high temperature resistant aircraft tire tread rubber, wherein the raw materials of the tread rubber are calculated by weight and specifically include:

[0080] (1) Natural rubber, 40-50 parts;

[0081] (2) styrene-butadiene rubber, 50-60 parts;

[0082] (3) a reinforcing system, 50-75 parts, comprising white carbon black, a coupling agent and a white carbon black dispersant in a weight ratio of (50-60):(3-5):(5-6); preferably, part of the white carbon black is modified by a coupling agent and then premixed with the styrene-butadiene rubber to obtain a modified styrene-butadiene rubber; more preferably, the white carbon black is hydrophobized by a mercaptosilane coupling agent and further reacted with an oxidant to oxidize the mercapto group to form a disulfide bond to obtain a modified white carbon black;

[0083] (4) A heat-resistant system, 5-10 parts, comprising nano-aluminum powder and nano-titanium dioxide in a weight ratio of (3-5):(3-4); preferably, the size of the nano-titanium dioxide is 15-100 nm, and the BET specific surface area is 10-200 m 2 / g; the specific gravity of nano aluminum powder is 2.3-3.1g / cm 3 , with a particle size of 100-300 nm; the heat-resistant system is premixed with at least part of the natural rubber to better improve the heat resistance of the natural rubber;

[0084] (5) an anti-aging system, 6-12 parts, comprising a p-phenylenediamine antioxidant, a ketoamine antioxidant and a protective wax in a weight ratio of (2-3):(2-3):(2-4);

[0085] Optionally, the phenylenediamine antioxidant includes at least one of N-(1,3-dimethyl)butyl-N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-N'-diphenyl-p-phenylenediamine and 4,4-bis(2,2-dimethylbenzyl)diphenylamine;

[0086] The ketoamine antioxidant includes at least one of diphenylaminoacetone, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline;

[0087] The protective wax includes at least one of Okerin1900 and RW590.

[0088] Preferably, the phenylenediamine antioxidant is N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, the ketoamine antioxidant is diphenylaminoacetone, and the protective wax is Okerin1900.

[0089] (6) a vulcanization system, 2-5 parts, comprising a vulcanizing agent, a vulcanization accelerator and a scorch retarder in a weight ratio of (15-25):(10-20):(1-2);

[0090] (7) Other auxiliary agents, 2-5 parts, including an active agent, wherein the active agent includes zinc oxide and stearic acid in a weight ratio of (5-8):(2-3).

[0091] After the tread rubber is hot-air aged at 150°C for 4 hours, the increase in Shore A hardness is less than 5%, the increase in 300% elongation stress is less than 10%, the increase in compression fatigue heat generation is less than 25%, the increase in wear loss is less than 35%, the decrease in tensile strength is less than 25%, the decrease in elongation at break is less than 25%, and the decrease in tear strength is less than 25%.

[0092] The method for preparing the high temperature resistant aircraft tire tread rubber comprises the following steps:

[0093] The natural rubber, styrene-butadiene rubber, the reinforcement system, the heat-resistant system, the anti-aging system and other additives are mixed and kneaded in proportion to obtain a first-stage mixed rubber;

[0094] After the first-stage mixed rubber is left standing for a certain period of time, the vulcanization system is added and mixed and kneaded to the second-stage discharge temperature; the second-stage mixture is discharged and sheeted, and cooled to obtain the final-mixed tread rubber.

[0095] According to the first optimization scheme (1) of the above preparation method, the raw materials are added in a certain mixing order, which specifically includes the following steps:

[0096] S1, first stage mixing:

[0097] 1.1 Mix natural rubber and styrene-butadiene rubber in proportion and knead them at a mixing temperature from 80-90°C to 90-105°C;

[0098] 1.2 Add the reinforcement system in proportion and mix and knead, the mixing temperature is increased from 90-105℃ to 125-135℃;

[0099] 1.3 Add heat-resistant system, anti-aging system and other additives in proportion and mix them. The mixing temperature is increased from 125-135℃ to 135-145℃;

[0100] 1.4 When the mixing temperature reaches 138-145°C, discharge a section of the mixture and press it into sheets, then cool it to obtain a section of mixed rubber.

[0101] S2, two-stage mixing:

[0102] 2.1 After the first-stage mixed rubber is left for 16h-24h, the first-stage mixed rubber and the vulcanization system are heated again to the second-stage discharge temperature of 95-105℃;

[0103] 2.2 The second-stage mixture is discharged and sheeted, and cooled to obtain the final tread rubber.

[0104] The second optimization scheme (2) is to modify part of the white carbon black of the reinforcement system with a coupling agent, and then premix it with the styrene-butadiene rubber to obtain a modified styrene-butadiene rubber, and then perform mixing and kneading of the components, which specifically includes the following steps:

[0105] S0, premixing treatment:

[0106] Step 1: Grind a water slurry of white carbon black with a solid content of 15-30 wt% for 5-15 minutes; at the same time, the silane coupling agent can be hydrolyzed for standby use;

[0107] Step 2: Add a mercaptosilane coupling agent and continue grinding for 10-30 minutes; the mercaptosilane coupling agent may be 3-mercaptopropyltrimethoxysilane or 3-mercaptopropylmethyldimethoxysilane;

[0108] Step 3: adding an oxidant and continuing grinding for 10-60 minutes to obtain a modified silica slurry; the oxidant may be selected from at least one of hydrogen peroxide, organic peroxide, hypochlorite, perborate, permanganate, bromine, and nitric oxide, and the oxidant is preferably used in a sufficient amount to fully oxidize the sulfhydryl group;

[0109] Step 4: mixing the styrene-butadiene rubber latex and the modified white carbon black slurry by high-speed collision, so as to achieve instant coagulation of the white carbon black slurry and the latex, and obtain the modified styrene-butadiene rubber;

[0110] S1, one-stage mixing

[0111] 1.1 Mix natural rubber and modified styrene-butadiene rubber in proportion and knead them at a mixing temperature from 80-90°C to 90-105°C;

[0112] 1.2 Add the remaining reinforcement system into the mixing and kneading process, and increase the mixing temperature from 90-105℃ to 125-135℃;

[0113] 1.3 Add heat-resistant system, anti-aging system and other additives in proportion and mix them. The mixing temperature is increased from 125-135℃ to 135-145℃;

[0114] 1.4 When the mixing temperature reaches the first discharging temperature of 138-145°C, discharge the first mixture and press it into sheets, and cool it to obtain a first mixed rubber;

[0115] S2, two-stage mixing:

[0116] 2.1 After the first-stage mixed rubber is left for 16h-24h, the first-stage mixed rubber and the vulcanization system are heated again to the second-stage discharge temperature of 95-105℃;

[0117] 2.2 The second-stage mixture is discharged and sheeted, and cooled to obtain the final tread rubber.

[0118] The third optimization scheme (3) is to premix the heat-resistant system with at least part of the natural rubber, which is beneficial to improving the heat resistance of the natural rubber. The third optimization scheme can be implemented alone or on the basis of the second optimization scheme, and specifically includes the following steps:

[0119] S0, premixing treatment:

[0120] Heat at least part of the natural rubber to 90-120° C., and slowly add the heat-resistant system to the natural rubber in steps for premixing at a high-speed shear rate of 2000-5000 r / min; optionally, simultaneously adopt steps 1 to 4 in the aforementioned second optimization scheme (2) to obtain a modified styrene-butadiene rubber;

[0121] S1, one-stage mixing

[0122] 1.1 Premixed natural rubber (or a combination of premixed and untreated natural rubber) and styrene-butadiene rubber (or modified styrene-butadiene rubber) are mixed and kneaded in proportion, and the mixing temperature is increased from 80-90°C to 90-105°C;

[0123] 1.2 Add the reinforcement system (or the remaining reinforcement system) to the mixing and kneading, and the mixing temperature is increased from 90-105°C to 125-135°C;

[0124] 1.3 Add heat-resistant system, anti-aging system and other additives in proportion and mix them. The mixing temperature is increased from 125-135℃ to 135-145℃;

[0125] 1.4 When the mixing temperature reaches the first discharging temperature of 138-145°C, discharge the first mixture and press it into sheets, and cool it to obtain a first mixed rubber;

[0126] S2, two-stage mixing:

[0127] 2.1 After the first-stage mixed rubber is left for 16h-24h, the first-stage mixed rubber and the vulcanization system are heated again to the second-stage discharge temperature of 95-105℃;

[0128] 2.2 The second-stage mixture is discharged and sheeted, and cooled to obtain the final tread rubber.

[0129] Example 1

[0130] An aircraft tire, comprising a high temperature resistant aircraft tire tread rubber, wherein the raw materials of the high temperature resistant aircraft tire tread rubber, measured in parts by weight, specifically include:

[0131] (1) 3L standard natural rubber, 40 parts;

[0132] (2) styrene butadiene rubber 1502, 60 parts;

[0133] (3) reinforcement system, 50 parts of white carbon black, 5 parts of γ-aminopropyltriethoxysilane and 3 parts of white carbon black dispersant H60;

[0134] (4) Heat-resistant system, including 3 parts of nano aluminum powder and 3 parts of nano titanium dioxide; the size of nano titanium dioxide is 15-100nm, and the BET specific surface area is 30-150m 2 / g; the specific gravity of nano aluminum powder is 2.5-2.8g / cm 3 , particle size is 120-250nm;

[0135] (5) Anti-aging system, 6 parts in total, including 2 parts of antioxidant 4020, 2 parts of antioxidant RD and 2 parts of protective wax;

[0136] (6) a vulcanization system comprising 1.8 parts of sulfur, 1.2 parts of a vulcanization accelerator NS, and 0.1 parts of a scorch retarder CTP;

[0137] (7) Other auxiliary agents, including an active agent, wherein the active agent includes 5 parts of zinc oxide and 2 parts of stearic acid.

[0138] The method for preparing the high temperature resistant aircraft tire tread rubber specifically comprises the following steps:

[0139] S1, first stage mixing:

[0140] 1.1 Mix natural rubber and styrene-butadiene rubber in proportion and knead them at a temperature ranging from 90°C to 100°C;

[0141] 1.2 Add the reinforcement system in proportion and mix and knead, the mixing temperature is increased from 100℃ to 130℃;

[0142] 1.3 Add heat-resistant system, anti-aging system and other additives in proportion and mix them at a mixing temperature from 130°C to 140°C;

[0143] 1.4 When the mixing temperature reaches 140°C, discharge a section of the mixture to a tablet press, cool it, and place it aside to obtain a section of mixed rubber.

[0144] S2, two-stage mixing:

[0145] 2.1 After the first-stage rubber mix is ​​left for 24 hours, the first-stage rubber mix and the vulcanization system are heated and mixed again to a second-stage discharge temperature of 100°C;

[0146] 2.2 The second-stage mixture is discharged to the tablet press, cooled, and placed to obtain the final tread rubber.

[0147] S3, extrude the semi-finished tread product on the extruder, and produce the finished tire through molding, vulcanization, etc.

[0148] Example 2

[0149] The difference between this embodiment and embodiment 1 is that the material composition ratio is different.

[0150] Example 3

[0151] The difference between this embodiment and embodiment 1 is that the material composition ratio is different.

[0152] Example 4

[0153] The difference between this embodiment and embodiment 3 is that part of the white carbon black is modified by a coupling agent and then premixed with the styrene-butadiene rubber to obtain modified styrene-butadiene rubber. The specific preparation steps of this embodiment are as follows:

[0154] S0. Pretreatment: Take 50 parts of white carbon black (about 83%), 6 parts of 3-mercaptopropyl trimethoxy silane coupling agent and pretreat styrene-butadiene rubber, including:

[0155] Step 1: prepare a silica slurry with a solid content of about 20 wt%, and grind the silica slurry for 10 minutes;

[0156] Dissolve 3-mercaptopropyltrimethoxysilane coupling agent in isopropanol, add acetic acid to adjust the pH to about 4.5, keep stirring, and let stand at room temperature for 20 minutes to complete the hydrolysis of the silane coupling agent;

[0157] Step 2: adding the hydrolyzed silane coupling agent to the silica slurry, adjusting the pH value to about 7.6 with a 5wt% sodium hydroxide solution, and continuing grinding at about 70°C for 20 minutes to react the silane coupling agent with the silica to obtain a hydrophobic silica slurry;

[0158] Step 3: adding sufficient hydrogen peroxide to the hydrophobic silica slurry, and continuing grinding at 70° C. for 1 hour to oxidize the sulfhydryl groups to form disulfide bonds, thereby obtaining a modified silica slurry;

[0159] Step 4: Mix the styrene-butadiene rubber latex and the modified silica slurry by high-speed collision, the collision speed is ≥2000rpm, the mixing time is 10-15 seconds, and after instant solidification, the modified styrene-butadiene rubber is obtained.

[0160] S1, first stage mixing:

[0161] 1.1 Mix natural rubber and modified styrene-butadiene rubber in proportion and knead them at a mixing temperature from 90°C to 100°C;

[0162] 1.2 Add the remaining reinforcement system materials in proportion and mix them, and the mixing temperature is increased from 100℃ to 130℃;

[0163] 1.3 Add heat-resistant system, anti-aging system and other additives in proportion and mix them at a mixing temperature from 130°C to 140°C;

[0164] 1.4 When the mixing temperature reaches 140°C, discharge a section of the mixture to a tablet press, cool it, and place it aside to obtain a section of mixed rubber.

[0165] S2, two-stage mixing:

[0166] 2.1 After the first-stage mixed rubber is left for 24 hours, the first-stage mixed rubber and the vulcanization system are heated again to the second-stage discharge temperature of 100°C;

[0167] 2.2 The second-stage mixture is discharged to the tablet press, cooled, and placed to obtain the final tread rubber.

[0168] S3, extrude the semi-finished tread product on the extruder, and produce the finished tire through molding, vulcanization, etc.

[0169] Example 5

[0170] The difference between this embodiment and embodiment 4 is that this embodiment further pre-treats the natural rubber and pre-mixes the heat-resistant system with the natural rubber. The specific preparation steps of this embodiment are as follows:

[0171] S0, pre-processing:

[0172] 40 parts of natural rubber (80%) were heated to 95°C, and nano titanium dioxide and nano aluminum powder were slowly added to the natural rubber in steps for premixing at a high shear rate of 3000 r / min;

[0173] After a portion of white carbon black is modified by a coupling agent, it is premixed with the styrene-butadiene rubber to obtain a modified styrene-butadiene rubber, which is the same as the pretreatment step in Example 4;

[0174] S1, first stage mixing:

[0175] 1.1 Mix the untreated natural rubber, the pretreated natural rubber and the modified styrene-butadiene rubber in proportion and knead them at a mixing temperature from 90°C to 100°C;

[0176] 1.2 Add the remaining reinforcement system materials in proportion and mix them, and the mixing temperature is increased from 100℃ to 130℃;

[0177] 1.3 Add the anti-aging system and other additives in proportion and mix them at a mixing temperature from 130°C to 140°C;

[0178] 1.4 When the mixing temperature reaches 140°C, discharge a section of the mixture to a tablet press, cool it, and place it aside to obtain a section of mixed rubber.

[0179] S2, two-stage mixing:

[0180] 2.1 After the first-stage mixed rubber is left for 24 hours, the first-stage mixed rubber and the vulcanization system are heated again to the second-stage discharge temperature of 100°C;

[0181] 2.2 The second-stage mixture is discharged to the tablet press, cooled, and placed to obtain the final tread rubber.

[0182] S3, extrude the semi-finished tread product on the extruder, and produce the finished tire through molding, vulcanization, etc.

[0183] Comparative Example 1

[0184] The difference between this embodiment and embodiment 3 is that this comparative example uses only 40 parts of white carbon black, and the amount of white carbon black used is relatively low.

[0185] Comparative Example 2

[0186] The difference between this embodiment and embodiment 3 is that this comparative example uses 70 parts of white carbon black, and the amount of white carbon black used is relatively high.

[0187] Comparative Example 3

[0188] The difference between this example and Example 3 is that the heat-resistant system of this comparative example only uses nano titanium dioxide.

[0189] Comparative Example 4

[0190] The difference between this embodiment and embodiment 3 is that the heat-resistant system of this comparative example only uses nano-aluminum powder.

[0191] The main material compositions of Examples 1-5 and Comparative Examples 1-4 are shown in Table 1:

[0192] Table 1

[0193]

[0194] Test Method

[0195] The Shore A hardness, 300% tensile stress, tensile strength, elongation at break, tear strength, compression fatigue heat generation, and wear loss of the tread rubbers of Examples 1-5 and Comparative Examples 1-4, as well as the Shore A hardness, 300% tensile stress, tensile strength, elongation at break, tear strength, compression fatigue heat generation, and wear loss after heat aging at 150°C×4h were tested, and the results are shown in Table 2.

[0196] 1. Shore A hardness: GB / T 531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore durometer method (Shore hardness)";

[0197] 2. 300% tensile stress, tensile strength and elongation at break: GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber";

[0198] 3. Tear strength: GB / T 529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens)";

[0199] 4. Compression fatigue heat generation: GB / T 1687.3-2016 "Determination of temperature rise and fatigue resistance of vulcanized rubber in flexure test Part 2: Compression flexure test";

[0200] 5. Wear loss: GB / T 1689-2014 "Determination of wear resistance of vulcanized rubber (using Akron abrasion machine)".

[0201] Table 2

[0202]

[0203]

[0204] According to the test results, the Shore A hardness of Examples 1-5 is 65-75 degrees, the 300% elongation stress is 14-18 MPa, the tensile strength is 26-31 MPa, the elongation at break is 550-650%, the tear strength is 90-120 kN / m, the compression fatigue heat generation is 25-35°C, and the wear loss is 0.3-0.4 cm 3 / 1.61km, and after heat aging at 150℃×4h, the Shore A hardness is 68-78 degrees, the 300% elongation stress is above 15MPa, the tensile strength is above 20MPa, the elongation at break is above 430%, the tear strength is above 70kN / m, the compression fatigue heat generation is 30-40℃, and the wear loss is 0.5cm 3 / 1.61km or less. That is, after hot air aging at 150°C×4h, the increase in Shore A hardness is less than 5%, the increase in 300% elongation stress is less than 10%, the increase in compression fatigue heat generation is less than 25%, the increase in wear loss is less than 35%, the decrease in tensile strength is less than 25%, the decrease in elongation at break is less than 25%, and the decrease in tear strength is less than 25%, which can meet the requirements of aircraft use for a longer time and stably.

[0205] In comparison, the increase in Shore A hardness after hot air aging of Comparative Examples 1-4 is greater than 5%, the increase in 300% elongation stress of Comparative Examples 1-2 is greater than 10%, the decrease in tensile strength of Comparative Example 1 is greater than 25%, the decrease in elongation at break of Comparative Examples 3 and 4 is greater than 25%, the decrease in tear strength of Comparative Example 1 is greater than 25%, the increase in compression fatigue heat generation of Comparative Example 1 is greater than 25%, and the increase in wear loss of Comparative Example 1 is greater than 35%.

[0206] The overall performance of Examples 1-5 is better than that of Comparative Examples 1-4, and Examples 4 and 5 after the pretreatment step have better overall performance than Examples 1-3.

[0207] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the present invention is intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention.

Claims

1. A high temperature resistant aviation tire tread rubber, characterized in that: The raw materials of the tread rubber include, by weight: The reinforcing system comprises white carbon black, a coupling agent and a white carbon black dispersant, and the weight ratio of the white carbon black, the coupling agent and the white carbon black dispersant is (50-60):(5-6):(3-5); The heat-resistant system includes nano-aluminum powder and nano-titanium dioxide, and the weight ratio of the nano-aluminum powder to the nano-titanium dioxide is (3-5):(3-4).

2. The high temperature resistant aircraft tire tread rubber according to claim 1, characterized in that: The anti-aging system comprises a p-phenylenediamine antioxidant, a ketoamine antioxidant and a protective wax, and the weight ratio of the p-phenylenediamine antioxidant, the ketoamine antioxidant and the protective wax is (2-3):(2-3):(2-4).

3. The high temperature resistant aircraft tire tread rubber according to claim 1, characterized in that: The vulcanization system comprises a vulcanizing agent, a vulcanization accelerator and a scorch retarder, and the weight ratio of the vulcanizing agent, the vulcanization accelerator and the scorch retarder is (15-25):(10-20):(1-2).

4. The high temperature resistant aircraft tire tread rubber according to any one of claims 1 to 3, characterized in that: A part of the white carbon black is modified by a coupling agent and then premixed with the styrene-butadiene rubber to obtain modified styrene-butadiene rubber.

5. The high temperature resistant aircraft tire tread rubber according to claim 4, characterized in that: The heat-resistant system meets at least one of the following conditions: (1) The size of nano titanium dioxide is 15-100nm, and the BET specific surface area is 10-200m 2 / g; (2) The specific gravity of nano aluminum powder is 2.3-3.1g / cm 3 , particle size is 100-300nm; (3) The heat-resistant system is premixed with at least a portion of the natural rubber.

6. A method for preparing the high temperature resistant aircraft tire tread rubber according to any one of claims 1 to 5, characterized in that: The steps include: S1, first stage mixing: The natural rubber, styrene-butadiene rubber, the reinforcement system, the heat-resistant system, the anti-aging system and other additives are mixed and kneaded in proportion to obtain a first-stage mixed rubber; S2, two-stage mixing: 2.1 After the first stage mixed rubber is left for 10h-30h, add the vulcanization system and mix and knead to the second stage discharge temperature; 2.2 The second-stage mixture is discharged and sheeted, and cooled to obtain the final tread rubber.

7. The preparation method according to claim 6, characterized in that: Step S1 specifically includes: 1.1 Mix natural rubber and styrene-butadiene rubber in proportion and knead them; 1.2 Add the reinforcement system into the mixed kneading according to the proportion; 1.3 Add heat-resistant system, anti-aging system and other additives according to proportion and mix; 1.4 When the mixing temperature reaches the first discharging temperature, discharge a section of the mixture and press it into sheets, then cool it to obtain a first section of mixed rubber.

8. The preparation method according to claim 7, characterized in that: At least one of the following conditions is met: In step 1.1, the mixing and kneading temperature is increased from 80-90°C to 90-105°C; In step 1.2, the mixing and kneading temperature is increased from 90-105°C to 125-135°C; In step 1.3, the temperature of the mixing and kneading is increased from 125-135°C to 135-145°C; In step 1.4, the discharge temperature of the first stage is 135-145°C; In step 2.1, the second stage discharge temperature is 95-105°C.

9. The preparation method according to claim 6, characterized in that: Before step S1, part of the white carbon black is modified by a coupling agent and then premixed with the styrene-butadiene rubber to obtain a modified styrene-butadiene rubber, which comprises the following steps: Step 1: Grind a slurry of silica with a solid content of 15-30wt% for 5-15 minutes; Step 2: Add mercaptosilane coupling agent and continue grinding for 10-30 minutes; Step 3: Add an oxidant and continue grinding for 10-60 minutes to obtain a modified silica slurry; Step 4: Mix the styrene-butadiene rubber latex and the modified silica slurry by high-speed collision to achieve instant coagulation of the silica slurry and the latex to obtain the modified styrene-butadiene rubber.

10. An aircraft tire, comprising the high temperature resistant aircraft tire tread rubber according to any one of claims 1 to 5 or the high temperature resistant aircraft tire tread rubber obtained by the preparation method according to any one of claims 6 to 9.

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