Preparation method of aramid fiber and nylon framework material for aircraft tire cap strip

Abstract

The invention relates to the field of aircraft tire manufacturing, in particular to a preparation method of an aramid fiber and nylon framework material for an aircraft tire cap strip. The method comprises the steps that S1, first twisting is conducted, specifically, a strand of 1100 dtex aramid precursor yarn is twisted on a ring twisting machine, the twisting direction is the Z direction, the twisting degree is 240-300 twists per meter, and three parts of aramid precursor yarn are twisted; a strand of 940 dtex nylon protofilament is twisted on a ring twisting machine, the twisting direction is the Z direction, the twisting degree is 160-200 twists per meter, and two parts of nylon protofilament are twisted; s2, plying and twisting: plying the twisted three parts of aramid fiber strands and two parts of nylon strands, and twisting the plied yarns along a reverse S direction with the twist degree of 240-300 twists per meter to obtain blended cords; s3, gum dipping; and S4, preparing a finished cotton rope, namely putting the blended cotton rope into a drawing machine, and drawing at 210-235 DEG C to obtain the finished cotton rope. Nylon with low linear density is selected, and the holding force is increased through a multi-strand twisting process, so that the effect of improving the strength is achieved, the cost is reduced, and the physical and chemical indexes are improved compared with those of a previous patent product.

Description

Technical Field

[0001] The invention relates to the field of aviation tire manufacturing, and in particular to a method for preparing aramid and nylon skeleton materials used for aviation tire cap strips. Background Art

[0002] The field of aviation tires has always been known for its robustness. Its radial design is relatively conservative, and it has been slow to adopt new technologies and new materials. However, with the booming aerospace industry, the performance of aviation tires has also made a significant leap. These tires not only have to face extreme challenges such as heavy loads, high-speed operation, extreme deformation, and high-pressure inflation, but also need to demonstrate excellent impact resistance, puncture resistance, and high temperature resistance, while withstanding the huge centrifugal force during takeoff and the violent impact at the moment of landing. In addition, lightweight design is also one of the indispensable requirements for aviation tires. Overall, the requirements for their performance are extremely stringent.

[0003] The structure of aircraft tires is similar to other tires. The core is composed of rubber and skeleton materials, among which the skeleton material plays a vital role. As the component that bears the main stress, the skeleton material must have high strength, low mass density, low moisture absorption, excellent impact resistance and high temperature resistance, fatigue resistance, and ideal fixed load and elongation at break to meet the stringent requirements of aircraft tires in terms of high pressure, high speed, large deformation and lightweight.

[0004] Historically, the skeleton material of aviation tires was initially made of cotton cords, but due to its limited strength, the tires had many layers, a heavy structure, a large mass, and poor fatigue resistance, and were gradually replaced by more excellent man-made fibers such as nylon and polyamide. Polyamide is known for its high strength, low density, good elasticity, low moisture absorption, high impact strength, and flex resistance; while nylon exhibits excellent wear resistance, fatigue resistance, chemical stability, and dimensional stability. However, the use of polyamide or nylon cord alone also has limitations, such as insufficient thermal stability, easy creep, obvious tire expansion after long-term use, and affects the overall performance, life, and shock resistance of the tire.

[0005] Therefore, the current mainstream trend is to use composite skeleton materials, especially to combine aramid with nylon / nylon to make composite cords. This design achieves complementary advantages of aramid and nylon / nylon by carefully adjusting the twist number, twist direction, denier and root number of the two. For example, the combination of aramid 1500D / 2 and N661890D / 1, although it has shown good physical and chemical properties, still faces problems such as high density leading to increased tire weight, which in turn affects aircraft performance. Summary of the invention

[0006] The present invention provides a method for preparing aramid and nylon skeleton materials for aviation tire cap strips, the purpose of which is to reduce the density of composite skeleton materials by using a new process while ensuring that the physical and chemical indicators of aramid and nylon skeleton materials are improved, so as to reduce the weight of the tire and meet the demand for lightweight aviation tires.

[0007] To achieve the above object, the technical solution of the present invention is:

[0008] The present invention provides a method for preparing aramid and nylon skeleton materials for aviation tire cap strips, comprising the following steps:

[0009] S1. Initial twisting: twisting a strand of 1100 dtex aramid yarn on a ring twisting machine, with the twisting direction being in the Z direction, the twist being 240 to 300 twists / m, and twisting three times; twisting a strand of 940 dtex nylon yarn on a ring twisting machine, with the twisting direction being in the Z direction, the twist being 160 to 200 twists / m, and twisting two times;

[0010] S2. Ply twisting, the three twisted aramid strands and two nylon strands are ply, the ply yarn is twisted in the reverse S direction, the twist is 240 to 300 twists / m, to obtain a blended rope;

[0011] S3. Dipping, the blended cord is placed in a first-bath dipping solution and immersed for 2 to 6 seconds, the temperature of the first-bath dipping solution is 25 to 30°C, and the first-bath dipping solution is a water-based adhesive; then the blended cord is taken out and dried at 100°C to 120°C for 1.2 to 1.5 minutes; the dried blended cord is placed in a second-bath dipping solution and immersed for 2 to 6 seconds, the temperature of the second-bath dipping solution is 25 to 30°C, and the second-bath dipping solution is a CBI-50 aqueous solution; then the blended cord is taken out and activated at 180 to 215°C for 1.2 to 1.5 minutes; after activation, the blended cord is placed in a third-bath dipping solution and immersed for 2 to 6 seconds, the temperature of the third-bath dipping solution is 20 to 30°C, and the third-bath dipping solution is RFL glue; finally, the blended cord is taken out and heat-set at 210 to 235°C for 1.2 to 1.5 minutes;

[0012] S4. Prepare finished cords, put the heat-set blended cords into a drawing machine and draw them at 210 to 235°C, with a drawing tension of 280 to 320 g / string and a speed of 4 to 6 m / min to obtain finished cords.

[0013] Furthermore, the ratio of the length of the aramid filament to the length of the nylon filament is 1.08:1.

[0014] Furthermore, the one-bath dipping solution is prepared by first adding 0.1 g of a wetting agent OT having a solid content of 10% to 15% to 96 g of softened water and stirring evenly at a room temperature of 20 to 25° C., then adding 2.9 g of EX-313 epoxy resin, stirring evenly, and then standing for eight hours.

[0015] Furthermore, the second-bath dipping solution is prepared by pouring 10 g of CBI-50 with a solid content of 50% into 90 g of softened water at a room temperature of 20-25° C., stirring evenly, and then directly using the solution.

[0016] Further, the method for preparing the three-bath dipping solution comprises the following steps:

[0017] 1) At room temperature of 20-25°C, add 2 kg of resorcinol-formaldehyde resin with a solid content of 75% to 23 kg of softened water, stir evenly, then slowly add 3 kg of 25% ammonia water, stirring while adding until all the water is added, stir evenly, and leave for 8 hours to obtain solution A;

[0018] 2) At room temperature of 20-25° C., 35 kg of butyl rubber latex having a solid content of 40% was mixed with 15 kg of softened water and 5 kg of natural rubber latex having a solid content of 60% and stirred evenly to obtain solution B;

[0019] 3) At room temperature of 20-25°C, 1 kg of formaldehyde was mixed with 11 kg of softened water to obtain solution C;

[0020] 4) At room temperature of 20-25°C, add solution A to solution B, stir evenly, then slowly add solution C last, stirring while adding until all the solution is added, stir evenly, and leave for 24 hours to obtain RFL glue solution.

[0021] The beneficial effects achieved by the present invention are:

[0022] The present invention uses a low-density aramid + nylon composite skeleton material. This choice is not only based on its excellent mechanical properties and lightweight characteristics, but also fully considers the maximization of material cost-effectiveness. Through a precisely designed multi-strand twisting process, the aramid + nylon fibers are twisted and wound multiple times, and then impregnated with three types of dipping solutions. This process significantly enhances the mutual holding force between the fibers, thereby achieving a significant improvement in the overall strength of the material at the macro level. This reinforcement mechanism not only optimizes the mechanical properties of the material, such as tensile strength, wear resistance, and fatigue resistance, but also enables the final product to achieve a significant reduction in weight while maintaining high strength, meeting the lightweight requirements of aviation tires; at the same time, it further reduces energy consumption and costs during production and use.

[0023] More importantly, since the composite skeleton material of the present invention has higher strength, the high-strength property provides a more solid support structure for the tire, effectively resisting the huge centrifugal force and ground friction generated during high-speed flight, significantly improving the durability and service life of the tire. At the same time, the enhanced safety performance also provides an important guarantee for aviation safety, reduces the potential risks caused by tire failure, and improves the overall flight safety level. DETAILED DESCRIPTION

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

[0025] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0026] 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 technical features indicated. 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 technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] The present invention provides a method for preparing aramid and nylon skeleton materials for aviation tire cap strips, comprising the following steps:

[0028] S1. Initial twisting: twisting a strand of 1100 dtex aramid yarn on a ring twisting machine, with the twisting direction being in the Z direction, the twist being 240 to 300 twists / m, and twisting three times; twisting a strand of 940 dtex nylon yarn on a ring twisting machine, with the twisting direction being in the Z direction, the twist being 160 to 200 twists / m, and twisting two times;

[0029] S2. Plying and twisting, the three twisted aramid strands and the two nylon strands are plyed, and the plyed yarn is twisted in the reverse S direction, with a twist of 240 to 300 twists / m to obtain a blended rope (i.e., 1100 dtex X 3 + 940 dtex X2);

[0030] S3. Dipping, the blended cord is placed in a first-bath dipping solution and immersed for 2 to 6 seconds, the temperature of the first-bath dipping solution is 25 to 30°C, and the first-bath dipping solution is a water-based adhesive; then the blended cord is taken out and dried at 100°C to 120°C for 1.2 to 1.5 minutes; the dried blended cord is placed in a second-bath dipping solution and immersed for 2 to 6 seconds, the temperature of the second-bath dipping solution is 25 to 30°C, and the second-bath dipping solution is a CBI-50 aqueous solution; then the blended cord is taken out and activated at 180 to 215°C for 1.2 to 1.5 minutes; after activation, the blended cord is placed in a third-bath dipping solution and immersed for 2 to 6 seconds, the temperature of the third-bath dipping solution is 20 to 30°C, and the third-bath dipping solution is RFL glue; finally, the blended cord is taken out and heat-set at 210 to 235°C for 1.2 to 1.5 minutes;

[0031] S4. Prepare finished cords, put the heat-set blended cords into a drawing machine and draw them at 210 to 235°C, with a drawing tension of 280 to 320 g / string and a speed of 4 to 6 m / min to obtain finished cords.

[0032] Furthermore, the ratio of the length of the aramid filament to the length of the nylon filament is 1.08:1.

[0033] Further, the preparation method of the one-bath dipping solution is: at a temperature of 20 to 25° C., first add 0.1 g of a wetting agent OT with a solid content of 10% to 15% to 96 g of softened water and stir evenly, then add 2.9 g of EX-313 epoxy resin (wherein EX-313 refers to the model of a water-based epoxy resin), stir evenly, and after standing for eight hours, obtain the one-bath dipping solution.

[0034] Furthermore, the preparation method of the second-bath dipping solution is as follows: at a temperature of 20 to 25° C., pour 10 g of CBI-50 (CBI-50 is a blocked isocyanate) with a solid content of 50% into 90 g of softened water, and stir evenly to obtain the second-bath dipping solution.

[0035] Further, the method for preparing the three-bath dipping solution comprises the following steps:

[0036] 1) At room temperature of 20-25°C, add 2 kg of resorcinol-formaldehyde resin with a solid content of 75% to 23 kg of softened water, stir evenly, then slowly add 3 kg of 25% ammonia water, stirring while adding until all the water is added, stir evenly, and leave for 8 hours to obtain solution A;

[0037] 2) At room temperature of 20-25° C., 35 kg of butyl rubber latex having a solid content of 40% was mixed with 15 kg of softened water and 5 kg of natural rubber latex having a solid content of 60% and stirred evenly to obtain solution B;

[0038] 3) At room temperature of 20-25°C, 1 kg of formaldehyde was mixed with 11 kg of softened water to obtain solution C;

[0039] 4) At room temperature of 20-25°C, add solution A to solution B, stir evenly, then slowly add solution C last, stirring while adding until all the solution is added, stir evenly, and leave for 24 hours to obtain RFL glue solution.

[0040] The present invention has achieved a significant technological breakthrough in the field of aircraft tire manufacturing. By introducing the innovative three-groove dipped RFL process, the adhesive force between the wire and the tire carcass is greatly enhanced. This design not only ensures the structural stability of the tire under extreme operating conditions (such as high speed, high temperature, and high pressure), but also effectively prevents the delamination problem caused by insufficient adhesive force, significantly improving the safety and service life of aircraft tires.

[0041] At the same time, the present invention is also innovative in material selection, and low-density nylon is specially selected as the core material. This nylon material itself has excellent mechanical properties and chemical stability, and through the advanced process of multi-strand twisting, the holding force between fibers is further enhanced, so that the overall strength of the cord is significantly improved. This reinforcement mechanism not only optimizes the tire's load-bearing capacity and fatigue resistance, but also reduces costs by reducing the amount of materials used, showing good economic benefits.

[0042] More importantly, the implementation of the present invention not only reduces costs, but also comprehensively improves the physical and chemical performance indicators of the product. Compared with the previous patented technology, the aircraft tire of the present invention shows more excellent performance in terms of wear resistance, aging resistance, tear resistance, etc., meeting the urgent needs of the modern aviation industry for high-performance and high-reliability tires.

[0043] Table 1 is a performance comparison between this patent and existing patented products:

[0044]

[0045] 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 method for preparing aramid and nylon skeleton materials for aviation tire cap strips, characterized in that: The following steps are involved: S1. Initial twisting: twisting a strand of 1100 dtex aramid yarn on a ring twisting machine, with the twisting direction being in the Z direction, the twist being 240 to 300 twists / m, and twisting three times; twisting a strand of 940 dtex nylon yarn on a ring twisting machine, with the twisting direction being in the Z direction, the twist being 160 to 200 twists / m, and twisting two times; S2. Ply twisting, the three twisted aramid strands and two nylon strands are ply, the ply yarn is twisted in the reverse S direction, the twist is 240 to 300 twists / m, to obtain a blended rope; S3. Dipping, the blended cord is placed in a first-bath dipping solution and immersed for 2 to 6 seconds, the temperature of the first-bath dipping solution is 25 to 30°C, and the first-bath dipping solution is a water-based adhesive; then the blended cord is taken out and dried at 100°C to 120°C for 1.2 to 1.5 minutes; the dried blended cord is placed in a second-bath dipping solution and immersed for 2 to 6 seconds, the temperature of the second-bath dipping solution is 25 to 30°C, and the second-bath dipping solution is a CBI-50 aqueous solution; then the blended cord is taken out and activated at 180 to 215°C for 1.2 to 1.5 minutes; after activation, the blended cord is placed in a third-bath dipping solution and immersed for 2 to 6 seconds, the temperature of the third-bath dipping solution is 20 to 30°C, and the third-bath dipping solution is RFL glue; finally, the blended cord is taken out and heat-set at 210 to 235°C for 1.2 to 1.5 minutes; S4. Prepare finished cords, put the heat-set blended cords into a drawing machine and draw them at 210 to 235°C, with a drawing tension of 280 to 320 g / string and a speed of 4 to 6 m / min to obtain finished cords.

2. The method for preparing aramid and nylon skeleton materials for aircraft tire cap strips according to claim 1, characterized in that: The ratio of the length of the aramid filament to the length of the nylon filament is 1.08:

1.

3. The method for preparing aramid and nylon skeleton materials for aircraft tire cap strips according to claim 1, characterized in that: The one-bath dipping solution is prepared as follows: at a room temperature of 20-25° C., firstly add 0.1 g of a wetting agent OT having a solid content of 10%-15% into 96 g of softened water and stir evenly, then add 2.9 g of EX-313 epoxy resin, stir evenly and then let stand for eight hours.

4. The method for preparing aramid and nylon skeleton materials for aircraft tire cap strips according to claim 1, characterized in that: The preparation method of the two-bath dipping solution is as follows: at a room temperature of 20-25° C., pour 10 g of CBI-50 with a solid content of 50% into 90 g of softened water, stir evenly and then use it directly.

5. The method for preparing aramid and nylon skeleton materials for aircraft tire cap strips according to claim 1, characterized in that: The method for configuring the three-bath dipping solution comprises the following steps: 1) At room temperature of 20-25°C, add 2 kg of resorcinol-formaldehyde resin with a solid content of 75% to 23 kg of softened water, stir evenly, then slowly add 3 kg of 25% ammonia water, stirring while adding until all the water is added, stir evenly, and leave for 8 hours to obtain solution A; 2) At room temperature of 20-25° C., 35 kg of butyl rubber latex having a solid content of 40% was mixed with 15 kg of softened water and 5 kg of natural rubber latex having a solid content of 60% and stirred evenly to obtain solution B; 3) At room temperature of 20-25°C, 1 kg of formaldehyde was mixed with 11 kg of softened water to obtain solution C; 4) At room temperature of 20-25°C, add solution A to solution B, stir evenly, then slowly add solution C last, stirring while adding until all the solution is added, stir evenly, and leave for 24 hours to obtain RFL glue solution.

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