A super-wide temperature range aerospace rubber and a preparation method thereof

Abstract

The application relates to the field of rubber, in particular to a super-wide-temperature-range rubber for spaceflight and a preparation method thereof. The raw material composition of the rubber is as follows in terms of weight parts: 80-140 parts of natural rubber, 9-17 parts of a plasticizer, 2-4 parts of bis-[gamma-(triethoxysilane) propyl] tetrasulfide, 1-3 parts of an antioxidant, 30-60 parts of carbon black, 25-30 parts of modified white carbon black, 3-10 parts of sulfur and 1-4 parts of zinc oxide. The rubber prepared by the application has high tensile strength and tear strength, low change rate of the tensile strength and tear strength after high-temperature treatment, can effectively pass the low-temperature brittleness test, and has low high-temperature and low-temperature compression permanent deformation, and the effect is excellent.

Description

Technical Field

[0001] This invention relates to the field of rubber, and more specifically to an ultra-wide temperature range aerospace rubber and its preparation method. Background Technology

[0002] Natural rubber is an important strategic resource and industrial raw material, playing an irreplaceable role in aircraft tire production. While my country has made breakthroughs in the domestic substitution of specialized aircraft tire rubber, the raw materials for this purpose suffer from a narrow applicable temperature range. Aircraft tires must withstand instantaneous high strain and high loads during takeoff and landing, and must endure a wide temperature range, from ambient ground temperature to extremely low temperatures at high altitudes and high braking temperatures. During high-altitude cruising, temperatures can drop as low as -40°C, while during landing and braking, tire temperatures can rapidly rise to around 70°C. Future space shuttles may experience temperatures as low as -60°C at high altitudes, while engine compartment temperatures can reach 120°C, meaning tires must withstand a temperature range of -60°C to 120°C. This places even wider temperature requirements on the rubber materials used in aircraft tires.

[0003] Compared to ordinary aircraft tires, aircraft tires made with special ultra-wide temperature range rubber can maintain stable performance under various complex temperature conditions, reducing the risk of tire failures caused by temperature changes, such as tire blowouts and accelerated wear, thereby improving the safety of aircraft takeoff and landing. The production of aircraft tires with special ultra-wide temperature range rubber is also one of the key technologies in the aviation industry. Its development can drive progress in related materials science, manufacturing processes, and other fields, raising the overall level of the national aviation industry.

[0004] In the field of high-performance natural rubber processing technology, the natural rubber used in high-end fields such as aircraft tires is mainly smoked sheet rubber. China has made breakthroughs in this area, but systematic research has not been carried out on the applicable temperature range of natural rubber for different processes. At present, research on high and low temperatures of natural rubber is still mainly focused on improving the low-temperature resistance or high-temperature resistance of natural rubber. For example, to improve the low-temperature resistance of natural rubber, plasticizers and toughening agents can be added to effectively reduce the brittle transition temperature and reduce cracking and fatigue. To improve the high-temperature resistance of natural rubber, antioxidant grafting and the addition of vulcanizing agents can be used to enhance the heat and oxygen aging resistance or high-temperature creep resistance of natural rubber. Meanwhile, China still lacks expertise in raw material research and development, supply chain collaboration, tire structure design, and performance testing for the preparation of aircraft tires using ultra-wide temperature range specialized rubber. There has been no systematic research on ultra-wide temperature range rubber materials, encompassing "wide temperature range natural rubber processing and production technology—rubber formulation system—aircraft tire application." Upstream and downstream collaborative innovation is weak, making it difficult to concentrate the research efforts of the entire supply chain to break through key technologies. Furthermore, manufacturers have limited testing coverage for ultra-wide temperature range specialized rubber aircraft tires, resulting in insufficient long-term fatigue performance data under extreme temperature ranges of -60℃ to 120℃ and incomplete dynamic simulation technology for multi-variable coupled operating conditions.

[0005] As my country enters a stage of high-quality development, the natural rubber industry is shifting from reliance on resource consumption to innovation-driven growth. Advanced high-end manufacturing industries, such as aerospace, place increasingly higher demands on the performance of rubber raw materials. However, for a long time, my country has lacked systematic research on fundamental scientific issues in the natural rubber field, resulting in insufficient technological innovation support and slow progress in key areas. Therefore, it is imperative to unite the entire natural rubber industry chain in technological innovation and integration, and to conduct research and development on key production technologies for ultra-wide temperature-range aerospace-specific rubber and its application in aircraft tires.

[0006] Therefore, it is urgent to carry out research and development of key production technologies for ultra-wide temperature range aerospace-specific rubber and related pilot production of aviation tires, so as to provide technical support for industrialization and implement the major initiatives of the national innovation-driven strategy. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes an ultra-wide temperature range aerospace rubber and its preparation method.

[0008] This invention provides an ultra-wide temperature range aerospace rubber, the raw materials of which are: natural rubber, plasticizer, bis-[γ-(triethoxysilyl)propyl]tetrasulfide, antioxidant, carbon black, modified silica, sulfur and zinc oxide.

[0009] In one embodiment, the ultra-wide temperature range aerospace rubber comprises, by weight, 80-140 parts natural rubber, 9-17 parts plasticizer, 2-4 parts bis-[γ-(triethoxysilyl)propyl]tetrasulfide, 1-3 parts antioxidant, 30-60 parts carbon black, 25-30 parts modified silica, 3-10 parts sulfur, and 1-4 parts zinc oxide.

[0010] In one embodiment, the plasticizer in the ultra-wide temperature range aerospace rubber is composed of adipic acid polyester plasticizer and epoxidized soybean oil in a weight ratio of 1:0.4-0.7.

[0011] In one embodiment, the adipic acid polyester plasticizer in the ultra-wide temperature range aerospace rubber is PN-850.

[0012] In one embodiment, the antioxidant in the ultra-wide temperature range aerospace rubber includes at least one of 4020, DOPPD, ODA, antioxidant AW, microcrystalline wax, and UV-326.

[0013] In one embodiment, the carbon black in the ultra-wide temperature range aerospace rubber includes N774.

[0014] In one embodiment, the aforementioned 80-140 parts of natural rubber consist of 60-100 parts of RSS1 and 20-40 parts of TSR20.

[0015] In one embodiment, the method for preparing modified silica includes: adding a solvent to a reaction vessel, adding silica, stirring, adding triphenyl phosphite and tributyl phosphate, continuing to stir, adding concentrated hydrochloric acid, heating to reflux reaction, cooling, separating, washing, and drying to obtain modified silica.

[0016] In one embodiment, in the method for preparing modified silica, the weight ratio of triphenyl phosphite to tributyl phosphate is 1:2-4.

[0017] In one embodiment, in the method for preparing modified silica, the weight ratio of silica to the total weight of triphenyl phosphite and tributyl phosphate is 1:0.1-0.3.

[0018] In one embodiment, in the preparation method of modified silica, the temperature and time of the reflux reaction are 90-98°C and 4-10 hours.

[0019] In one embodiment, in the method for preparing modified silica, the weight ratio of silica to concentrated hydrochloric acid is 1:0.01-0.04.

[0020] The present invention also provides a method for preparing the ultra-wide temperature range aerospace rubber, comprising: (1) Preheat the mixing chamber, add natural rubber, mix and obtain the first mixture; (2) Continue heating, add zinc oxide, antioxidant, carbon black and plasticizer in sequence, and continue mixing to obtain the second mixture; (3) Heat up again, add modified silica and bis-[γ-(triethoxysilane)propyl]tetrasulfide in sequence, mix, heat to 115-125℃ to discharge, cool, and then send to open mill, add sulfur to mix, sheet, store, and obtain the ultra-wide temperature range aerospace rubber.

[0021] In one embodiment, (2) the temperature is further increased to 90-100°C.

[0022] In one embodiment, (3) is heated again to 105-113°C.

[0023] In one embodiment, sulfur is added and mixed at 40-60°C for 2-6 minutes.

[0024] The advantages of this invention compared to the prior art are as follows: This invention utilizes natural rubber (e.g., RSS1, TSR20), plasticizers, bis-[γ-(triethoxysilyl)propyl]tetrasulfide, antioxidants, carbon black, modified silica, sulfur, and zinc oxide to prepare ultra-wide temperature range aerospace rubber. The rubber prepared by this invention exhibits high tensile and tear strength, low change rate of tensile and tear strength after high-temperature treatment, effectively passes low-temperature brittleness tests, and shows low compression set at both high and low temperatures, demonstrating excellent performance.

[0025] This invention utilizes the synergistic effect of triphenyl phosphite and tributyl phosphate to provide strong chemical bonding and flexible chain segment regulation, ensuring both the interfacial bonding between silica and rubber and improving dispersibility, thereby enhancing the overall performance of the rubber. The bis-[γ-(triethoxysilyl)propyl]tetrasulfide in this invention strengthens the interfacial bonding between the filler and rubber in the rubber system, significantly improving tensile strength and tear strength, and enhancing high-temperature and low-temperature stability. This invention uses the adipic acid polyester plasticizer PN-850, which combines ester groups (polar) and long-chain methylene groups (non-polar), exhibiting good compatibility with natural rubber. The epoxidized soybean oil molecule contains long-chain fatty acid esters (similar to the carbon chain structure of rubber, non-polar) and epoxy groups (polar), demonstrating excellent compatibility with natural rubber. The two work together to improve compatibility with the rubber system, enhance system stability, and improve the overall performance of the rubber.

[0026] This invention utilizes PN-850 and epoxidized soybean oil to enhance and improve the strength and temperature resistance of rubber. A weight ratio of adipic acid polyester plasticizer to epoxidized soybean oil of 1:0.4-0.7 is preferred. This invention selects triphenyl phosphite and tributyl phosphate to co-modify silica, which significantly improves the strength and temperature resistance of rubber. In the rubber system of this invention, the use of bis-[γ-(triethoxysilyl)propyl]tetrasulfide effectively improves rubber strength and suppresses deformation at high and low temperatures.

[0027] The rubber of this invention has excellent properties, a wide temperature range, and a simple preparation process, making it a promising candidate for application. Attached Figure Description

[0028] Figure 1 : Tensile strength test diagram of rubber 1.

[0029] Figure 2 : Tensile strength test diagram of rubber 2. Detailed Implementation

[0030] The invention will now be described in detail with reference to specific embodiments.

[0031] RSS1: Liankangming No. 1 smoked sheet rubber, Shanghai Liankangming Chemical. TSR20: Tianye Rubber Group TSR 20. Epoxidized soybean oil: Jinan Rongguang Chemical Co., Ltd. Silica: Evonik AEROSILA 200 silica.

[0032] I. Preparation of Modified Silica Modified silica 1: Add 120 mL of toluene solvent to a reaction vessel, add 50 g of silica, stir at 500 rpm for 10 minutes, add triphenyl phosphite and tributyl phosphate in a mass ratio of 1:2 (the weight ratio of silica to the total mass of the two is 1:0.2), continue stirring for 10 minutes, add 37 wt% concentrated hydrochloric acid (the mass ratio of silica to concentrated hydrochloric acid is 1:0.03), heat to 90 °C and reflux for 6 hours, cool to 35 °C, filter and separate, wash the separated solid with toluene and anhydrous ethanol in sequence, and then dry under vacuum at 60 °C to constant weight to obtain modified silica.

[0033] Modified silica 2: Add 120 mL of toluene solvent to a reaction vessel, add 50 g of silica, stir at 500 rpm for 10 minutes, add triphenyl phosphite (the weight ratio of silica to triphenyl phosphite is 1:0.2), continue stirring for 10 minutes, add 37 wt% concentrated hydrochloric acid (the mass ratio of silica to concentrated hydrochloric acid is 1:0.03), heat to 90 °C and reflux for 6 hours, cool to 35 °C, filter and separate, wash the separated solid with toluene and anhydrous ethanol in sequence, and then dry under vacuum at 60 °C to constant weight to obtain modified silica.

[0034] Modified silica 3: Add 120 mL of toluene solvent to a reaction vessel, add 50 g of silica, stir at 500 rpm for 10 minutes, add tributyl phosphate (the weight ratio of silica to tributyl phosphate is 1:0.2), continue stirring for 10 minutes, add 37 wt% concentrated hydrochloric acid (the mass ratio of silica to concentrated hydrochloric acid is 1:0.03), heat to 90 °C and reflux for 6 hours, cool to 35 °C, filter and separate, wash the separated solid with toluene and anhydrous ethanol in sequence, and then dry under vacuum at 60 °C to constant weight to obtain modified silica.

[0035] II. Preparation of Rubber The composition of each rubber by weight is shown in Table 1. In Table 1, the A value represents the weight ratio of PN-850 and epoxidized soybean oil.

[0036] Table 1: Rubber Composition The difference between rubbers numbered 7-8 and rubber 1 is that modified silica 1 is replaced by modified silica 2 and 3 respectively. The difference between rubber numbered 9 and rubber 1 is that bis-[γ-(triethoxysilyl)propyl]tetrasulfide is replaced by KH550.

[0037] The preparation method of the above-mentioned rubber includes: opening the mixing chamber and running it at 85 rpm and preheating it to 70°C, adding RSS1 and TSR20 in sequence, mixing for 2 minutes, raising the temperature to 100°C, adding zinc oxide, antioxidant, carbon black and plasticizer in sequence, mixing for 3 minutes, raising the temperature to 110°C, adding modified silica and bis-[γ-(triethoxysilyl)propyl]tetrasulfide in sequence, mixing for 6 minutes, raising the temperature to 125°C to discharge the material, naturally cooling it to 50°C, sending it into a two-roll mill, adding sulfur at 50°C and mixing for 4 minutes, sheeting, storing, and obtaining the ultra-wide temperature range aerospace rubber.

[0038] III. Rubber Testing The rubber prepared above was stored at room temperature for 2 days before its performance was tested.

[0039] The test methods are as follows: Tensile strength, tear strength, and the change rate of tensile strength and tear strength after treatment at 140℃ for 72h were tested according to GB / T 528-2009 and GB / T 529-2008; low-temperature brittleness was tested according to GB / T 15256-2014; high-temperature compression set was tested according to GB / T 7759.1-2015; and low-temperature compression set was tested according to GB / T 7759.2-2014. The results are shown in Tables 2-3 and 2-3. Figure 1-2 .in, Figure 1-2 These are tensile strength test diagrams for rubbers 1 and 2, respectively.

[0040] Table 2: Tensile Strength and Tear Strength Tests Table 3: Temperature Resistance Test According to the test results in Table 2-3, the rubber prepared by this invention has high tensile strength and tear strength, low change rate of tensile strength and tear strength after high temperature treatment, can effectively pass the low temperature brittleness test, and has low permanent deformation under high temperature and low temperature compression, showing excellent results.

[0041] This invention utilizes the synergistic effect of triphenyl phosphite and tributyl phosphate, which provide strong chemical bonding and flexible chain segment regulation. This ensures both the interfacial bonding between silica and rubber and improves dispersibility, thereby enhancing the overall performance of the rubber. The bis-[γ-(triethoxysilyl)propyl]tetrasulfide in this invention strengthens the interfacial bonding between the filler and rubber in the rubber system, significantly improving tensile strength and tear strength, and enhancing high-temperature and low-temperature stability. This invention uses the adipic acid polyester plasticizer PN-850, which combines ester groups (polar) and long-chain methylene groups (non-polar), exhibiting good compatibility with rubber. The epoxidized soybean oil molecule contains long-chain fatty acid esters (similar to the carbon chain structure of rubber, non-polar) and epoxy groups (polar), demonstrating excellent compatibility with rubber. The two work together to improve compatibility with the rubber system, enhance system stability, and improve the overall performance of the rubber.

[0042] A comparison of rubbers 1 and 3-4 shows that using PN-850 and epoxidized soybean oil can enhance and improve the strength and temperature resistance of the rubber. Furthermore, a weight ratio of adipic acid polyester plasticizer and epoxidized soybean oil within the range of 1:0.4-0.7 is preferred; this can be derived from a comparison of rubbers 1 and 5-6. A comparison of rubbers 1 and 7-8 shows that the combined modification of silica with triphenyl phosphite and tributyl phosphate improves the strength and temperature resistance of the rubber more effectively than modification with triphenyl phosphite and tributyl phosphate alone. In the rubber system of this invention, the use of bis-[γ-(triethoxysilyl)propyl]tetrasulfide can effectively improve the rubber strength and suppress deformation at high and low temperatures.

[0043] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention within the scope of the technology disclosed in the present invention, and all such substitutions or changes should be covered within the scope of protection of the present invention.

Claims

1. A type of ultra-wide temperature range aerospace rubber characterized in that, The raw materials, by weight, are: 80-140 parts natural rubber, 9-17 parts plasticizer, 2-4 parts bis-[γ-(triethoxysilyl)propyl]tetrasulfide, 1-3 parts antioxidant, 30-60 parts carbon black, 25-30 parts modified silica, 3-10 parts sulfur and 1-4 parts zinc oxide. The plasticizer is composed of adipic acid polyester plasticizer and epoxidized soybean oil in a weight ratio of 1:0.4-0.7; The adipic acid polyester plasticizer is PN-850; The preparation method of modified silica includes: adding solvent to a reaction vessel, adding silica, stirring, adding triphenyl phosphite and tributyl phosphate, continuing to stir, adding concentrated hydrochloric acid, heating and refluxing reaction, cooling, separating, washing, and drying to obtain modified silica; The weight ratio of triphenyl phosphite to tributyl phosphate is 1:2-4; the weight ratio of silica to the total weight of triphenyl phosphite and tributyl phosphate is 1:0.1-0.

3.

2. The ultra-wide temperature range aerospace rubber according to claim 1, characterized in that, Anti-aging agents include at least one of 4020, DOPPD, ODA, anti-aging agent AW, microcrystalline wax, and UV-326.

3. The ultra-wide temperature range aerospace rubber according to claim 1, characterized in that, Carbon black includes N774; or, natural rubber includes 60-100 parts RSS1 and 20-40 parts TSR20.

4. The ultra-wide temperature range aerospace rubber according to claim 1, characterized in that, The temperature and time for the reflux reaction are 90-98℃ and 4-10 hours. Alternatively, the weight ratio of silica to concentrated hydrochloric acid is 1:0.01-0.

04.

5. A method for preparing ultra-wide temperature range aerospace rubber according to any one of claims 1-4, characterized in that, include: (1) Preheat the mixing chamber, add natural rubber, mix and obtain the first mixture; (2) Continue heating, add zinc oxide, antioxidant, carbon black and plasticizer in sequence, and continue mixing to obtain the second mixture; (3) Heat up again, add modified silica and bis-[γ-(triethoxysilane)propyl]tetrasulfide in sequence, mix, heat to 115-125℃ to discharge, cool, and then send to open mill, add sulfur to mix, sheet, store, and obtain the ultra-wide temperature range aerospace rubber.

6. The preparation method according to claim 5, characterized in that, Add sulfur and mix at 40-60℃ for 2-6 minutes.

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