A method of making a multi-fiber blend for use in the construction of an aircraft tire

Abstract

The present application relates to the field of continuous fiber framework material preparation method, and discloses a kind of multi-fiber blending method for preparing aviation tire framework material.The framework material is made of high-strength, high-thermal-conductivity carbon fiber, high-strength, lightweight aramid fiber and high-strength, high-toughness nylon fiber.The three fibers are first prepared into initial framework materials using different dip-coating systems and preparation processes, and the twisting directions of the three framework materials are consistent.Then the three initial framework materials are twisted into one strand using a twisting machine, and the twisting direction of the mixed fibers is consistent with the twisting direction of the three initial framework materials.Then the prepared fibers are immersed in RFL dip-coating solution, and subjected to drying, activation, setting and other process treatments to obtain the fiber framework material.The prepared mixed fiber framework material has the characteristics of lightweight, high toughness, high strength and high thermal conductivity, and can meet the performance requirements of aviation tires for framework materials, thus having important strategic value.

Description

Technical Field

[0001] This invention relates to the field of continuous fiber skeleton material preparation technology, and specifically to a multi-fiber blending method for preparing aircraft tire skeleton materials. Background Technology

[0002] As the sole point of contact with the ground, aircraft tires not only support the entire weight and impact forces during taxiing, takeoff, and landing, but also directly affect the aircraft's handling stability, safety, and landing distance. Therefore, they are crucial and indispensable key components in aircraft operation. Their design, manufacturing, and maintenance must meet extremely high methodological standards and safety requirements to ensure the safe and efficient operation of the aircraft under various complex weather and ground conditions. Therefore, aircraft tires need to meet the following three requirements:

[0003] First, aircraft tires will be subjected to huge impact forces during takeoff and landing. Therefore, the skeleton material inside the aircraft tire needs to be able to withstand huge and multi-directional alternating loads such as tension, compression, rotation and shear without local breakage or debonding from the base rubber, so as to ensure the performance and stability of the aircraft tire.

[0004] Secondly, in order to reduce the overall weight of the aircraft and increase its effective payload, the weight of each component of the aircraft needs to be as low as possible while meeting the usage requirements; therefore, the weight of the aircraft tire frame material should also be as low as possible.

[0005] Third, during takeoff and landing, aircraft tires are subjected to tremendous impacts, and friction between the tires and the ground generates a huge amount of heat. Therefore, as a skeleton material suitable for aircraft tires, it not only needs to have high strength, high toughness, and lightweight properties, but also needs to have high thermal conductivity to quickly balance the temperature difference between the tire and the environment.

[0006] Therefore, most current aircraft tires use high-performance and lightweight continuous fiber skeleton materials to replace steel cords. To improve the performance and stability of aircraft tires and prevent debonding and localized failures, the fibers undergo special impregnation and twisting treatments. This enhances the interfacial adhesion between the fibers and rubber, as well as the tensile strength, fatigue strength, and impact toughness of the fiber skeleton material, thereby improving the performance of the aircraft tire.

[0007] Currently, aircraft tire carcass materials mostly use single-fiber materials such as nylon or aramid, each exhibiting excellent performance in terms of strength, toughness, or temperature resistance. However, with the development of the aviation industry, the requirements for tire performance are increasingly demanding, and single-fiber materials can no longer meet all the requirements. Therefore, the industry is gradually shifting towards using blended methods of two fibers, hoping to achieve more ideal overall performance through the complementary advantages of the materials.

[0008] Nevertheless, even with blending methods, it remains difficult to simultaneously and perfectly meet all the high standards required for the carcass materials of aircraft tires: high toughness to resist frequent deformation and impact, high strength to withstand huge takeoff and landing loads, and high thermal conductivity to quickly disperse and dissipate heat generated by high-speed friction. Balancing and optimizing these properties is currently the focus and challenge in the research and development of aircraft tire carcass materials. Summary of the Invention

[0009] This invention provides a multi-fiber blending method for preparing aircraft tire skeleton materials. By twisting carbon fiber, aramid fiber and nylon 66 fiber together, a continuous fiber skeleton material is prepared, which leverages the advantages of each of the three fibers to solve the problem that existing aircraft tire skeleton materials cannot simultaneously meet the requirements of high toughness, high strength and high thermal conductivity.

[0010] To achieve the above objectives, the method of the present invention is as follows: First, carbon fiber, aramid fiber and nylon 66 fiber are impregnated with resin to prepare initial skeleton materials. Then, the three prepared initial skeleton materials are twisted together by a twisting machine. The twisted fiber material is then impregnated twice with RFL impregnation solution. After drying, activation and shaping processes, a continuous fiber skeleton material suitable for aircraft tires can be prepared.

[0011] Furthermore, since carbon fiber, aramid fiber, and nylon 66 fiber have different hardness, elongation at break, and filament shape, different impregnation and preparation processes are used to prepare the three fibers into initial skeleton materials.

[0012] Furthermore, the one-bath impregnation system for carbon fiber consists of plasma water, epoxy resin, 2-methylpentanediamine, butadiene latex, and resorcinol-formaldehyde resin.

[0013] Furthermore, after the continuous carbon fibers are impregnated with the one-bath impregnation solution, they are dried at 190°C for 90 seconds, and then heated to 200°C for activation reaction for 90 seconds, and then heat-set at 200°C for 120 seconds; then the set carbon fiber bundles are twisted by a twisting machine to form the initial carbon fiber skeleton material.

[0014] Furthermore, the initial carbon fiber skeleton material has a twist of 30-300 twists / meter, and the direction is either Z-axis or S-axis.

[0015] Furthermore, firstly, aramid fiber and nylon 66 fiber are twisted separately using a twisting machine. Then, the twisted aramid fiber and nylon 66 fiber are impregnated with RFL impregnation solution, dried at 200℃ for 90s, and then heated to 230℃ for activation reaction for 90s. Finally, they are heat-set at 200℃ for 120s to prepare the initial skeleton material of aramid fiber and nylon 66 fiber.

[0016] Furthermore, the preparation method of the RFL impregnation system is as follows: 2.8 kg of resorcinol-formaldehyde resin with a solid content of 75% is mixed with 16.5 kg of softened water and 2.2 kg of ammonia water with a concentration of 25% to obtain solution A; 42 kg of butadiene-pyrrolidone latex with a solid content of 40% is mixed with 14 kg of softened water to obtain solution B; solution A and solution B are mixed and stirred, and after standing for 24 hours, 22.5 kg of adhesive RP is added, and after mixing and stirring, the RFL impregnation system is obtained.

[0017] Furthermore, firstly, the three prepared initial fiber skeleton materials are twisted together using a twisting machine; then, the twisted fibers are impregnated with an RFL impregnation system, dried at 200°C for 90 seconds, and then heated to 230°C for an activation reaction for 90 seconds. Finally, the fibers are heat-set and stretched at 200°C using a drawing machine to obtain the final product of this invention.

[0018] Furthermore, the twist of the three initial skeleton materials is 20-50 twists / meter, and the direction is consistent with the direction of the three initial skeleton materials.

[0019] Furthermore, the tensile strength is 800g / piece, and the vehicle speed is 6 meters / minute.

[0020] The beneficial effects of this invention are:

[0021] This invention prepares a continuous fiber skeleton material by mixing carbon fiber, aramid fiber and nylon 66 fiber, which can give full play to the characteristics of high strength and high thermal conductivity of carbon fiber, high strength and lightweight of aramid fiber and high toughness and high strength of nylon 66 fiber.

[0022] By utilizing the gradient relationship between the modulus, hardness, and elongation at break among the three types of fibers, and by employing different twists, one-bath impregnation systems, and initial skeleton material preparation processes for different fibers, it can be ensured that when the skeleton material prepared by mixing and twisting is subjected to external loads, the internal fiber filaments can break as simultaneously as possible, thus maximizing the load-bearing capacity of all fibers.

[0023] Meanwhile, by using different twisting treatments on different fibers, the fatigue resistance of the three fibers can be maximized, so that the prepared continuous fiber skeleton material has high strength, high toughness, high thermal conductivity and fatigue resistance, which meets the requirements of aircraft tires. Detailed Implementation

[0024] The method scheme of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of method features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if the word "and / or" appears throughout the text, it means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the method solutions of various embodiments can be combined with each other, but this must be based on the ability of a person skilled in the art to implement them. When the combination of method solutions is contradictory or cannot be implemented, it should be considered that such a combination of method solutions does not exist and is not within the scope of protection claimed by this invention.

[0026] To avoid slight differences in composition, the main materials involved in this invention are described as follows:

[0027] The manufacturer of bisphenol A type epoxy resin is Nagase Sangyo Co., Ltd. of Japan.

[0028] The manufacturer of 2-methylpentanediamine is DuPont (China) Co., Ltd.

[0029] The manufacturer of butyl rubber latex is Jiangsu Yatai Chemical Co., Ltd.

[0030] The manufacturer of resorcinol-formaldehyde resin is Shandong Shengquan Chemical Co., Ltd.

[0031] The adhesive RP manufacturer is Yixing Liangxing New Materials Co., Ltd.

[0032] This invention provides a method for preparing multi-fiber blended materials for aircraft tire skeletons, specifically including the following steps:

[0033] S1. Preparation of initial carbon fiber skeleton material: First, continuous carbon fibers are immersed in a carbon fiber one-bath impregnation solution, then dried, activated and heat-set. Finally, the set carbon fiber bundles are initially twisted by a twisting machine to form initial carbon fiber skeleton material.

[0034] S2. Preparation of initial skeleton materials of aramid fiber and nylon 66 fiber: First, aramid fiber and nylon 66 fiber are initially twisted by a twisting machine. Then, the twisted aramid fiber and nylon 66 fiber are immersed in RFL impregnation solution. Finally, after drying, activation and heat setting treatment, the initial skeleton materials of aramid fiber and nylon 66 fiber are prepared.

[0035] S3. Twisting: The three initial fiber skeleton materials are twisted together using a twisting machine.

[0036] S4. Preparation of finished rope: First, the twisted fiber rope is immersed in RFL impregnation solution, and then dried and activated before being heat-set and stretched in a stretching machine to obtain the final product of the present invention.

[0037] The fiber skeleton material disclosed in this invention is made by twisting together carbon fiber, aramid fiber, and nylon fiber. Since the elongation rates of carbon fiber, aramid fiber, and nylon fiber are different, in order to maximize the strength of the three fibers and achieve the best final product performance, the three fibers must first be prepared into initial skeleton materials with different twists. The processes for preparing the initial skeleton materials of the three fibers are different: the initial skeleton material of carbon fiber is prepared by first impregnating with resin and then twisting, while the initial skeleton materials of aramid fiber and nylon fiber are prepared by first twisting and then impregnating with resin.

[0038] Carbon fiber, aramid fiber, and nylon fiber have different hardness, elongation at break, and initial raw material shapes, so they use different one-bath impregnation systems. The one-bath impregnation system for carbon fiber consists of plasma water, bisphenol A epoxy resin, 2-methylpentanediamine, butyl pyrrolidone latex, and resorcinol-formaldehyde resin; the one-bath impregnation system for aramid fiber and nylon fiber is RFL.

[0039] The preparation method of the carbon fiber one-bath impregnation solution is as follows: 50g of deionized water, 15g of bisphenol A epoxy resin and 5g of 2-methylpentanediamine are mixed and stirred for 30min, and then reacted at a constant temperature of 25℃ for 6 hours. Then, 20g of butadiene latex and 5g of resorcinol-formaldehyde resin are added, mixed and stirred for 30min, and then reacted at a constant temperature of 25℃ for 3 hours to obtain the carbon fiber one-bath impregnation solution.

[0040] Continuous carbon fibers are impregnated in an impregnation tank for 120 seconds (the impregnation tank contains a one-bath impregnation solution for the carbon fibers), then dried at 190°C for 90 seconds, and then heated to 200°C for an activation reaction for 90 seconds, and then heat-set at 200°C for 120 seconds; then the heat-set carbon fiber bundle is drawn to a twisting machine to perform initial twisting of the continuous carbon fibers, with a twist of 30-300 twists / meter, and the twisting direction is S or Z, to form the initial carbon fiber skeleton material.

[0041] Furthermore, the continuous carbon fiber can be of type 3K or T800.

[0042] Furthermore, the initial twist of the continuous carbon fiber is 60 twists / meter, and the twisting direction is S-axis.

[0043] Aramid fibers of 1500 dtex and nylon 66 fibers of 1000 dtex were twisted separately using a twisting machine to form fiber bundles. The initial twist of the aramid fibers was 200-400 twists / meter, and the initial twist of the nylon fibers was 300-500 twists / meter. The twisting direction was the same as that of the initial twist of continuous carbon fibers, which was either S-direction or Z-direction. The two twisted fiber bundles were then impregnated for 120 seconds in an impregnation tank containing RFL impregnation solution. They were then dried at 200°C for 90 seconds, and after drying, the temperature was raised to 230°C for activation reaction for 90 seconds. Finally, they were heat-set at 200°C for 120 seconds to obtain the initial aramid skeleton material and the nylon 66 skeleton material.

[0044] Furthermore, the initial twist of aramid fiber is 200 twists / meter, and the initial twist of nylon 66 fiber is 400 twists / meter, with the twisting direction being S-direction.

[0045] Then, the prepared initial carbon fiber skeleton material, aramid skeleton material and nylon 66 skeleton material are twisted into a fiber rope by a twisting machine. The twist of the three initial skeleton materials is 20-50 twists / meter, and the twisting direction is the same as that of the three initial skeleton materials. Then, the prepared fiber rope is impregnated twice with RFL impregnation solution for 3 minutes, and then dried at 200℃ for 90 seconds. After drying, the temperature is raised to 230℃ for activation reaction for 90 seconds. The RFL curing reaction product is used to bond the three ropes together. Then, it is put into a drawing machine for heat setting and drawing at 200℃ to obtain the finished continuous fiber skeleton material for aircraft tires.

[0046] Furthermore, the twist of the three initial skeleton materials is 30 twists / meter, and the twisting direction is S-axis.

[0047] Furthermore, the stretching tension of the stretching machine is 800g / piece, and the machine speed is 6 meters / minute.

[0048] The preparation method of the RFL impregnation solution is as follows: 2.8 kg of resorcinol-formaldehyde resin with a solid content of 75% is mixed with 16.5 kg of softened water and 2.2 kg of ammonia water with a concentration of 25% to obtain solution A; 42 kg of butadiene latex with a solid content of 40% is mixed with 14 kg of softened water to obtain solution B; solution A and solution B are mixed and stirred, and after standing for 24 hours, 22.5 kg of adhesive RP is added, and after mixing and stirring, the RFL impregnation system is obtained.

[0049] The beneficial effects of this method will be explained in detail below with reference to Comparative Example 1 and Comparative Example 2.

[0050] Comparative Example 1

[0051] Traditional continuous carbon fiber impregnation solutions are generally aqueous solutions of pMDI and epoxy resin. The preparation method of the aqueous solution of pMDI and epoxy resin is as follows: 5g of pMDI and 2g of bisphenol A type epoxy resin are added to 93g of deionized water and dissolved to obtain the aqueous solution of pMDI and epoxy resin.

[0052] Comparative Example 2

[0053] Preparation of traditional aramid fiber and nylon 66 fiber blended skeleton materials:

[0054] Aramid fibers of 2500 dtex and nylon 66 fibers of 2000 dtex were twisted separately using a twisting machine to form fiber bundles. The twist of the aramid fibers was 200 twists / meter, and the twist of the nylon 66 fibers was 400 twists / meter, both in the S-direction. The two twisted fiber bundles were then impregnated for 120 seconds in an RFL impregnation bath. They were then dried at 200°C for 90 seconds, followed by an activation reaction at 230°C for 90 seconds, and finally heat-set at 200°C for 120 seconds to obtain the initial aramid skeleton material and the nylon 66 skeleton material.

[0055] Then, the prepared initial aramid skeleton material and nylon 66 skeleton material are mixed and twisted by a twisting machine to prepare a mixed twisted yarn bundle with a twist of 30 twists / meter and an S-direction. The mixed and prepared yarn is then impregnated a second time with RFL impregnation solution, dried at 200℃ for 90s, and then heated to 230℃ for activation reaction for 90s. Finally, it is put into a drawing machine for heat setting and drawing at 200℃ to obtain the finished continuous fiber skeleton material.

[0056] The RFL impregnation system is prepared as follows: 2.8 kg of resorcinol-formaldehyde resin with a solid content of 75% is mixed with 16.5 kg of softened water and 2.2 kg of ammonia water with a concentration of 25% to obtain solution A; 42 kg of butadiene-pyrrolidone latex with a solid content of 40% is mixed with 14 kg of softened water to obtain solution B; solution A and solution B are mixed and stirred, and after standing for 24 hours, 22.5 kg of adhesive RP is added, and after mixing and stirring, the RFL impregnation system is obtained.

[0057] Performance testing

[0058] The properties of the initial carbon fiber skeleton material treated by this method, the properties of the continuous fiber skeleton material prepared in Comparative Example 1, the properties of the final product of this invention, and the properties of the blended skeleton material of Comparative Example 2 were tested according to GB / T 33099-2016. The results of the comparison of the elongation at break of the three initial skeleton materials and the blended skeleton material of this invention are shown in Tables 1, 2 and 3.

[0059] Table 1. Test Results of Carbon Fiber Initial Skeleton Material Properties

[0060]

[0061] Table 2. Performance Test Results of Blended Fiber Reinforced Materials

[0062]

[0063] Table 3. Test results of elongation at break of initial skeleton material and blended skeleton material.

[0064]

[0065] As shown in Table 1, for continuous carbon fibers of 3K and T800, the initial carbon fiber skeleton material prepared using the impregnation solution of the present invention has a hardness of 71 gf, which is much lower than the hardness (236) of the skeleton material prepared in Comparative Example 1, indicating that the initial carbon fiber skeleton material prepared by the present invention has better toughness. Moreover, the initial carbon fiber skeleton material prepared by the present invention has a fracture strength and interfacial adhesion of 446 N and 172 N, respectively, which are significantly higher than the fracture strength (371) and interfacial adhesion (121) of the skeleton material prepared in Comparative Example 1. The test results show that the carbon fiber impregnation solution of the present invention can prepare initial carbon fiber skeleton materials with excellent performance.

[0066] As shown in Table 2, for almost the same weight, the hardness of the carbon fiber / aramid / nylon blended skeleton material prepared by the present invention is 377 gf, which is much lower than the hardness (564) of the skeleton material prepared by Comparative Example 2, indicating that the blended skeleton material prepared by the present invention has better toughness. Moreover, the fracture strength and interfacial adhesion of the blended skeleton material prepared by the present invention are 982 N and 348 N, respectively, which are significantly higher than the fracture strength (713) and interfacial adhesion (261) of the skeleton material prepared by Comparative Example 2, demonstrating the superiority of the multi-fiber blending method of the present invention in the preparation of aerospace tire skeleton materials.

[0067] As shown in Table 3, the breaking elongation of the final product prepared by the present invention is almost the same as that of the three initial fiber skeleton materials, indicating that the multi-fiber blending method of the present invention can enable the three fibers to break almost simultaneously when subjected to external load, thus maximizing the load-bearing capacity of the three fibers.

[0068] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for preparing multi-fiber blended spinning of aircraft tire carcass material, characterized in that, Includes the following steps: S1. Preparation of initial carbon fiber skeleton material: First, continuous carbon fibers are immersed in a carbon fiber one-bath impregnation solution, then dried, activated and heat-set, and finally the set carbon fiber bundles are initially twisted by a twisting machine. S2. Preparation of initial skeleton materials for aramid and nylon fibers: First, aramid and nylon fibers are initially twisted by a twisting machine. Then, the twisted aramid and nylon fibers are immersed in RFL impregnation solution and finally dried, activated and heat-set. S3. Twisting: The three prepared initial fiber skeleton materials are twisted together using a twisting machine. S4. Preparation of finished rope: First, the twisted fiber rope is immersed in RFL impregnation solution, and then after drying and activation, it is put into the drawing machine for heat setting and drawing. The preparation method of the carbon fiber one-bath impregnation solution is as follows: 50g of deionized water, 15g of bisphenol A epoxy resin and 5g of 2-methylpentanediamine are mixed and stirred for 30min, and then reacted at a constant temperature of 25℃ for 6 hours. Then, 20g of butadiene latex and 5g of resorcinol-formaldehyde resin are added, mixed and stirred for 30min, and then reacted at a constant temperature of 25℃ for 3 hours to obtain the carbon fiber one-bath impregnation solution. The continuous carbon fiber is immersed in a carbon fiber impregnation solution for 120 seconds, then dried at 190°C for 90 seconds, and then heated to 200°C for activation reaction for 90 seconds, and then heat-set at 200°C for 120 seconds. The heat-set carbon fiber bundles are drawn to a twisting machine to perform initial twisting on the continuous carbon fibers. The twist is 30-300 twists / meter, and the twisting direction is either S or Z. The initial twist of aramid fiber is 200-400 twists / meter, and the initial twist of nylon fiber is 300-500 twists / meter. The twisting direction is either S-direction or Z-direction, and is consistent with the initial twisting direction of continuous carbon fiber. Carbon fiber initial skeleton material, aramid fiber initial skeleton material and nylon fiber initial skeleton material are twisted together into a fiber rope using a twisting machine. The twist of the three initial skeleton materials is 20-50 twists / meter, and the twisting direction is consistent with the initial twisting direction of the three initial skeleton materials. The prepared fiber rope is then impregnated a second time with RFL impregnation solution for 3 minutes, and then dried at 200℃ for 90 seconds. After drying, the temperature is raised to 230℃ for activation reaction for 90 seconds. Then it is put into a drawing machine for heat setting and drawing at 200℃ with a drawing tension of 800g / rod and a machine speed of 6 meters / minute.

2. The method for preparing multi-fiber blended spinning of aircraft tire skeleton material according to claim 1, characterized in that: The initial twist of the continuous carbon fiber is 60 twists / meter, and the twisting direction is S-axis.

3. The method for preparing multi-fiber blended spinning of aircraft tire skeleton material according to claim 1, characterized in that: The initial twist of aramid fiber is 200 twists / meter, and the initial twist of nylon fiber is 400 twists / meter. The twisting direction for both is S-direction.

4. A method for preparing multi-fiber blended spinning of aircraft tire skeleton material according to claim 1 or 3, characterized in that: The twisted aramid fibers and nylon fibers were respectively immersed in RFL impregnation solution, then dried at 200℃ for 90s, and then heated to 230℃ for activation reaction for 90s, and then heat-set at 200℃ for 120s.

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