Multi-fiber blending method for preparing aircraft tire framework material

Abstract

The invention relates to the field of preparation methods of continuous fiber framework materials, and discloses a multi-fiber blending method for preparing an aircraft tire framework material. The framework material is formed by mixing and twisting high-strength and high-heat-conductivity carbon fibers, high-strength and light aramid fibers and high-strength and high-toughness nylon fibers. According to the characteristics of the three fibers, firstly, different one-bath impregnation systems and preparation processes are adopted, the three fibers are prepared into initial framework materials, and the twisting directions of the three framework materials are consistent; then the three initial framework materials are mixed and twisted into one strand through a twisting machine, and the direction of mixed and twisted fibers is consistent with the twisting direction of the three initial framework materials; then, fibers prepared through mixed twisting are soaked in RFL gum dipping liquid, and the fiber framework material can be prepared through drying, activating, sizing and other process treatment. The prepared mixed twisted fiber framework material has the characteristics of light weight, high toughness, high strength and high thermal conductivity, can meet the performance requirements of aircraft tires on the framework material, and has important strategic value.

Description

Technical Field

[0001] The invention relates to the technical field of continuous fiber skeleton material preparation, and in particular to a multi-fiber blending method for preparing aviation tire skeleton materials. Background Art

[0002] As the only ground-attached part of an aircraft, aircraft tires not only support the entire weight and impact force of the aircraft during taxiing, takeoff and landing, but also directly affect the aircraft's handling stability, safety and landing run distance. Therefore, they are vital and indispensable key components in aircraft operation. Their design, manufacturing and maintenance must meet extremely high method standards and safety requirements to ensure that the aircraft can operate safely and efficiently 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 tensile, compression, rotation, shear and other alternating loads without local fracture and debonding from the base rubber, so as to ensure the performance and stability of the aircraft tire;

[0004] Second, in order to reduce the overall weight of the aircraft and increase the effective load, the weight of each component of the aircraft needs to be as low as possible while meeting the use requirements; therefore, the weight of the aircraft tire frame material must also be as low as possible;

[0005] Third, while aviation tires are subjected to tremendous impact during takeoff and landing, the friction between the tires and the ground will also instantly generate huge heat. Therefore, as a skeleton material suitable for aviation tires, it is not only necessary to have high strength, high toughness, and light weight, but also to have high thermal conductivity to quickly balance the temperature difference between the tire and the environment.

[0006] Therefore, current aircraft tires mostly use high-performance and lightweight continuous fiber skeleton materials to replace steel cords. In order to improve the performance and stability of aircraft tires and avoid debonding and local failure, the fibers need to be specially dipped and twisted to improve the interfacial adhesion between the fiber and rubber, as well as the fracture strength, fatigue resistance and impact toughness of the fiber skeleton material, thereby improving the performance of aircraft tires.

[0007] At present, the skeleton materials of aircraft tires are mostly made of single fiber materials such as nylon or aramid, which have excellent performance in strength, toughness or temperature resistance. However, with the development of the aviation industry, the requirements for tire performance are increasing, and single fiber materials can no longer meet all conditions. Therefore, the industry has gradually turned to the blending method of two fibers, in order to achieve more ideal comprehensive performance through the complementary advantages of the materials.

[0008] Nevertheless, even with the blending method, it is still difficult to perfectly meet all the high standards for skeleton materials of aircraft tires at the same time: high toughness to resist frequent deformation and impact, high strength to bear the huge take-off and landing loads, and high thermal conductivity to quickly disperse and discharge the heat generated by high-speed friction. The balance and optimization between these properties is the focus and difficulty of the current research and development of aircraft tire skeleton materials. Summary of the invention

[0009] The present invention provides a multi-fiber blending method for preparing an aviation tire skeleton material. A continuous fiber skeleton material is prepared by twisting carbon fiber, aramid fiber and nylon 66 fiber together, and the respective advantages of the three fibers are brought into play to solve the problem that the existing aviation tire skeleton material cannot simultaneously meet the requirements of high toughness, high strength and high thermal conductivity.

[0010] In order to achieve the above-mentioned purpose, the method scheme of the present invention is: first, carbon fiber, aramid fiber and nylon 66 fiber are respectively dipped into glue to prepare initial skeleton materials, and then the three prepared initial skeleton materials are mixed and twisted into one strand through a twisting machine, and then the mixed fiber material is dipped in RFL dipping liquid for the second time, and after drying, activation and shaping process treatment, a continuous fiber skeleton material suitable for aviation tires can be prepared.

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

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

[0013] Furthermore, after the continuous carbon fiber is impregnated with the one-bath dipping solution, it is dried at 190°C for 90s, and after drying, the temperature is raised to 200°C for activation reaction for 90s, and then heat-set at 200°C for 120s; then the fixed carbon fiber tow is twisted by a twisting machine to be twisted into an initial carbon fiber skeleton material.

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

[0015] Furthermore, first, the aramid fiber and nylon 66 fiber were passed through a twisting machine to twist the two fibers respectively, and then the twisted aramid fiber and nylon 66 fiber were impregnated with RFL dipping solution, and then dried at 200°C for 90s. After drying, the temperature was raised to 230°C for activation reaction for 90s, and then heat-set at 200°C for 120s to prepare the initial skeleton materials of aramid fiber and nylon 66 fiber.

[0016] Furthermore, the preparation method of the RFL dipping 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 a solution A; 42 kg of butadiene latex with a solid content of 40% is mixed with 14 kg of softened water to obtain a solution B; the solution A and the solution B are mixed and stirred, and after standing for 24 hours, 22.5 kg of adhesive RP is added, and the RFL dipping system is obtained after mixing and stirring.

[0017] Furthermore, first, the three prepared fiber initial skeleton materials are twisted by a twisting machine, and the three initial skeleton materials are twisted together; then the mixed and twisted fibers are impregnated with an RFL dipping system, dried at 200°C for 90s, and after drying, the temperature is raised to 230°C for activation reaction for 90s, and then enter the drawing machine for heat setting and drawing at 200°C to obtain the final product of the present invention.

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

[0019] Furthermore, the drawing tension is 800g / root and the vehicle speed is 6 meters / minute.

[0020] Beneficial effects of the present invention:

[0021] The present invention prepares a continuous fiber skeleton material by twisting carbon fiber, aramid fiber and nylon 66 fiber, which can give full play to the high strength and high thermal conductivity characteristics of carbon fiber, the high strength and light weight characteristics of aramid fiber and the high toughness and high strength characteristics 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 adopting different twists, one-bath dipping systems, and initial skeleton material preparation processes for different fibers, it can be ensured that when the skeleton material prepared by mixed twisting is subjected to external loads, the internal fiber filaments can be broken as simultaneously as possible, thereby exerting the maximum bearing capacity of all fibers.

[0023] At the same time, by twisting different fibers with different twist degrees, the fatigue resistance of the three fibers can be maximized, so that the prepared continuous fiber skeleton material has the characteristics of high strength, high toughness, high thermal conductivity and fatigue resistance, meeting the use requirements of aviation tires. DETAILED DESCRIPTION

[0024] The following will be combined with embodiments to clearly and completely describe the method scheme in the present invention. 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 method personnel in the field without creative work are within the scope of protection of the present invention.

[0025] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated method features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if the meaning of "and / or" appearing in the full text is to include three parallel schemes, taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the method schemes between the various embodiments can be combined with each other, but it must be based on the ability of ordinary method personnel in this field to implement. When the combination of method schemes is contradictory or cannot be implemented, it should be considered that the combination of such method schemes does not exist and is not within the scope of protection required by the present invention.

[0026] In order to avoid slight differences in ingredients, the main materials involved in the present invention are described as follows:

[0027] The manufacturer of bisphenol A epoxy resin is Japan's Nagase Industry Co., Ltd.

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

[0029] The manufacturer of Dingbi 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] The present invention provides a multi-fiber blending method for preparing an aviation tire skeleton material, which specifically comprises the following steps:

[0033] S1. Preparation of initial carbon fiber skeleton material: first, the continuous carbon fiber is impregnated in a carbon fiber bath dipping solution, then dried, activated and heat-set, and finally the shaped carbon fiber tow is initially twisted by a twisting machine to form an 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 respectively subjected to initial twisting by a twisting machine, and then the twisted aramid fiber and nylon 66 fiber are impregnated with RFL dipping solution, and finally, after drying, activation and heat setting treatment, the initial skeleton materials of aramid fiber and nylon 66 fiber are prepared;

[0035] S3. Ply twisting: The three prepared initial fiber skeleton materials are twisted by a twisting machine, and the three initial skeleton materials are twisted together;

[0036] S4. Prepare finished cords: First, the mixed and twisted fiber rope is immersed in the RFL dipping solution, and then after drying and activation, it enters the drawing machine for heat setting and drawing to obtain the final product of the present invention.

[0037] The fiber skeleton material disclosed in the present invention is made of three materials, carbon fiber, aramid fiber and nylon fiber, which are twisted together. Since the elongation of carbon fiber, aramid fiber and nylon fiber are different, in order to maximize the strength of the three fibers and make the final product performance optimal, the three fibers need to be prepared into initial skeleton materials with different twists. The three fibers are prepared into initial skeleton materials in different processes, wherein the initial skeleton material of carbon fiber is firstly dipped in glue and then twisted, and the processing process of the initial skeleton materials of aramid fiber and nylon fiber is firstly twisted and then dipped in glue.

[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 dipping systems. The one-bath dipping system for carbon fiber is composed of plasma water, bisphenol A epoxy resin, 2-methylpentanediamine, butadiene latex and resorcinol-formaldehyde resin; the one-bath dipping 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 30 minutes, and then the mixture is kept at 25°C for 6 hours. Then, 20g of butadiene latex and 5g of resorcinol-formaldehyde resin are added, and the mixture is mixed and stirred for 30 minutes, and then the mixture is kept at 25°C for 3 hours to obtain the carbon fiber one-bath impregnation solution.

[0040] The continuous carbon fiber is immersed in a dipping tank for 120 seconds (the dipping tank contains a bath dipping solution for the carbon fiber), then dried at 190°C for 90 seconds, and after drying, the temperature is raised to 200°C for activation reaction for 90 seconds, and then heat-set at 200°C for 120 seconds; the heat-set carbon fiber tow is then pulled to a twisting machine, and the continuous carbon fiber is initially twisted with a twist of 30-300 twists / m and a twisting direction of S or Z to make an initial carbon fiber skeleton material.

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

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

[0043] Aramid fibers of 1500 dtex and nylon 66 fibers of 1000 dtex are twisted in a twisting machine to form fiber bundles; wherein the twist of the aramid fibers is 200-400 twists / m, and the twist of the nylon fibers is 300-500 twists / m, and the twisting directions are the same as the twisting directions of the continuous carbon fibers, both in the S direction or the Z direction; then the two twisted fiber bundles are respectively immersed in a dipping tank for 120 seconds, wherein the dipping tank is filled with RFL dipping solution, and then dried at 200°C for 90 seconds, and then heated to 230°C for activation reaction for 90 seconds after drying, and then heat-set at 200°C for 120 seconds to obtain initial aramid skeleton materials and nylon 66 skeleton materials.

[0044] Furthermore, the twist of the aramid fiber is 200 twists / m, the twist of the nylon 66 fiber is 400 twists / m, and the twisting direction is S direction.

[0045] Then, the prepared initial carbon fiber skeleton material, aramid skeleton material and nylon 66 skeleton material are mixed and twisted into a fiber rope through a twisting machine, and the twist of the three initial skeleton materials is 20-50 twists / m, and the twisting direction is consistent with the twisting direction of the three initial skeleton materials; then the mixed and twisted fiber rope is secondary impregnated with RFL dipping solution for 3 minutes, and then dried at 200°C for 90s, and after drying, the temperature is raised to 230°C for activation reaction for 90s, and the three ropes are bonded together using the RFL curing reaction product, and then enter the drawing machine for heat setting and drawing at 200°C to obtain a finished product of continuous fiber skeleton material for aviation tires.

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

[0047] Furthermore, the drafting tension of the drafting machine is 800 g / strand and the machine speed is 6 m / min.

[0048] The preparation method of the RFL dipping 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 a solution A; 42 kg of butadiene latex with a solid content of 40% is mixed with 14 kg of softened water to obtain a solution B; the solution A and the solution B are mixed and stirred, and after standing for 24 hours, 22.5 kg of adhesive RP is added, and the RFL dipping system is obtained after mixing and stirring.

[0049] The beneficial effects of the present method will be described in detail below in conjunction with Comparative Example 1 and Comparative Example 2.

[0050] Comparative Example 1

[0051] The conventional continuous carbon fiber impregnation solution is generally a pMDI and epoxy resin aqueous solution, and the preparation method of the pMDI and epoxy resin aqueous solution is as follows: 5g pMDI and 2g bisphenol A epoxy resin are added into 93g deionized water, and the pMDI and epoxy resin aqueous solution is obtained after dissolving.

[0052] Comparative Example 2

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

[0054] Aramid fibers of 2500 dtex and nylon 66 fibers of 2000 dtex are twisted in a twisting machine to form fiber bundles; wherein the twist of the aramid fiber is 200 twists / m, and the twist of the nylon 66 fiber is 400 twists / m, and both are in the S direction; then the two twisted fiber bundles are respectively immersed in a dipping tank for 120 seconds, wherein the dipping tank is filled with RFL dipping solution, and then dried at 200°C for 90 seconds, and after drying, the temperature is raised to 230°C for activation reaction for 90 seconds, and then heat-set at 200°C for 120 seconds to obtain initial aramid skeleton materials and nylon 66 skeleton materials.

[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 / m and an S direction. Then, the mixed and twisted prepared rope is secondary impregnated with RFL dipping solution, and then dried at 200°C for 90s. After drying, the temperature is raised to 230°C for activation reaction for 90s, and then enters the drawing machine for heat setting and drawing at 200°C to obtain a finished continuous fiber skeleton material.

[0056] The preparation method of the RFL dipping 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 a solution A; 42 kg of butadiene latex with a solid content of 40% is mixed with 14 kg of softened water to obtain a solution B; the solution A and the 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 dipping system is obtained.

[0057] Performance Testing

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

[0059] Table 1 Carbon fiber initial skeleton material performance test results

[0060]

[0061] Table 2 Blended fiber skeleton material performance test results

[0062]

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

[0064]

[0065] It can be seen from Table 1 that for 3K and T800 continuous carbon fibers, the hardness of the initial carbon fiber skeleton material prepared by the dipping solution of the present invention is 71gf, 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; and the fracture strength and interface adhesion of the initial carbon fiber skeleton material prepared by the present invention are 446N and 172N, respectively, which are significantly higher than the fracture strength (371) and interface adhesion (121) of the skeleton material prepared in Comparative Example 1; it can be seen from the test results that the carbon fiber dipping solution of the present invention can prepare an initial carbon fiber skeleton material with excellent performance.

[0066] It can be seen from Table 2 that at almost the same weight, the hardness of the carbon fiber / aramid / nylon blended skeleton material prepared by the present invention is 377gf, which is much lower than the hardness (564) of the skeleton material prepared in Comparative Example 2, indicating that the blended skeleton material prepared by the present invention has better toughness; and the fracture strength and interface adhesion of the blended skeleton material prepared by the present invention are 982N and 348N, respectively, which are significantly higher than the fracture strength (713) and interface adhesion (261) of the skeleton material prepared in Comparative Example 2, reflecting the superiority of the multi-fiber blending method of the present invention in preparing aviation tire skeleton materials.

[0067] It can be seen from Table 3 that the elongation at break of the final product prepared by the present invention is almost the same as the elongation at break of each of the three fiber initial skeleton materials, indicating that the multi-fiber blending method of the present invention can make the three fibers break almost simultaneously when subjected to external loads, thereby exerting the maximum load-bearing capacity of the three fibers.

[0068] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A multi-fiber blending method for preparing an aircraft tire skeleton material, characterized in that: The following steps are involved: S1. Preparation of initial carbon fiber skeleton material: first, the continuous carbon fiber is impregnated in a carbon fiber bath dipping solution, then dried, activated and heat-set, and finally the shaped carbon fiber tow is initially twisted by a twisting machine; S2. Preparation of initial skeleton materials of aramid fiber and nylon fiber: First, the aramid fiber and nylon fiber are respectively subjected to initial twisting by a twisting machine, and then the twisted aramid fiber and nylon fiber are impregnated with RFL dipping solution, and finally dried, activated and heat-set; S3. Ply twisting: The three prepared initial fiber skeleton materials are twisted by a twisting machine, and the three initial skeleton materials are twisted together; S4. Prepare finished cords: First, the mixed and twisted fiber ropes are immersed in the RFL dipping solution, and then after drying and activation, they are put into the drawing machine for heat setting and drawing.

2. A multi-fiber blending method for preparing an aircraft tire skeleton material according to claim 1, characterized in that: 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 30 minutes, and then reacted at a constant temperature of 25°C for 6 hours, and then 20g of butadiene latex and 5g of resorcinol-formaldehyde resin are added, and after mixing and stirring for 30 minutes, the mixture is reacted at a constant temperature of 25°C for 3 hours to obtain the carbon fiber one-bath impregnation solution.

3. The multi-fiber blending method for preparing an aircraft tire skeleton material according to claim 2, characterized in that: The continuous carbon fiber is immersed in the carbon fiber one-bath dipping solution for 120 seconds, then dried at 190°C for 90 seconds, and after drying, the temperature is raised to 200°C for activation reaction for 90 seconds, and then heat-set at 200°C for 120 seconds.

4. A multi-fiber blending method for preparing an aircraft tire skeleton material according to claim 3, characterized in that: The heat-set carbon fiber tow is pulled to the twisting machine to perform initial twisting on the continuous carbon fiber, with a twist degree of 30-300 twists / m and a twisting direction of S or Z.

5. A multi-fiber blending method for preparing aircraft tire skeleton material according to claim 4, characterized in that: The initial twist of the continuous carbon fiber is 60 twists / meter, and the twisting direction is S direction.

6. The multi-fiber blending method for preparing an aircraft tire skeleton material according to claim 1, characterized in that: The twist of the initial twist of aramid fiber is 200-400 twists / m, and the twist of the initial twist of nylon fiber is 300-500 twists / m. The twisting direction is S or Z, and is consistent with the initial twist direction of continuous carbon fiber.

7. A multi-fiber blending method for preparing aircraft tire skeleton material according to claim 6, characterized in that: The twist of the initial twist of the aramid fiber is 200 twists / m, and the twist of the initial twist of the nylon fiber is 400 twists / m, and the twisting direction is S direction.

8. A multi-fiber blending method for preparing an aircraft tire skeleton material according to claim 6 or 7, characterized in that: The twisted aramid fiber and nylon fiber were immersed in the RFL dipping solution respectively, and then dried at 200°C for 90s. After drying, the temperature was raised to 230°C for activation reaction for 90s, and then heat-set at 200°C for 120s.

9. The multi-fiber blending method for preparing an aircraft tire skeleton material according to claim 1, characterized in that: The carbon fiber initial skeleton material, the aramid fiber initial skeleton material and the nylon fiber initial skeleton material are twisted into a fiber rope through a twisting machine. The twist degree of the three initial skeleton materials is 20-50 twists / m, and the twisting direction is consistent with the initial twist direction of the three initial skeleton materials.

10. A multi-fiber blending method for preparing aircraft tire skeleton material according to claim 9, characterized in that: The mixed and twisted fiber rope is then dipped in RFL dipping solution for a second time for 3 minutes, then dried at 200°C for 90 seconds, and after drying, heated to 230°C for activation reaction for 90 seconds, and then enters the drawing machine for heat setting and drawing at 200°C, with a drawing tension of 800g / rod and a speed of 6m / min.

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