A nylon cord and a tire prepared therefrom

Abstract

The present invention relates to the field of tire rubber materials, and particularly to a nylon cord and a tire prepared therefrom. The cord comprises at least two nylon 6 filaments. Each nylon 6 filament is first individually subjected to an initial Z-twist to form a strand, and each strand is then combined and subjected to a final S-twist in the opposite direction to the initial twist to form a nylon cord; the specification of the nylon cord is any one of 840D / 2, 1260D / 2, and 1890D / 2; the initial twist number of the nylon 6 filament is 5%-50% lower than that of the traditional nylon 6 filament of the same specification; the twist angle of the nylon 6 filament is 1°-6° lower than that of the traditional nylon 6 filament of the same specification; the final twist number of the nylon 6 strand is 5%-50% lower than that of the traditional nylon 6 strand of the same specification; the final twist angle of the nylon 6 strand is 2°-12° lower than that of the traditional nylon 6 strand of the same specification; the density of the nylon 6 filament is 7D-12D. The tire prepared by using the nylon cord provided by the present invention breaks through the limitation of the application of nylon 6 cord in tires due to its poor performance and dimensional stability, and can achieve the purpose of reducing costs while maintaining the performance of the tire.

Description

Technical Field

[0001] The present invention relates to the field of tire rubber materials, and particularly to a nylon cord and a tire prepared therefrom. Background Art

[0002] In the tire industry, the commonly used cord materials are nylon 66 and nylon 6. Among them, nylon 6 has a greater cost advantage than nylon 66. However, when nylon 6 is used as the tire skeleton material, compared with nylon 66, the tire size stability and physical properties are poor. The main reason is that nylon 66 has higher crystallinity and more orderly arrangement than nylon 6, so that the modulus of nylon 66 is higher than that of nylon 6. Therefore, in terms of properties such as elongation at constant load and heat shrinkage, nylon 66 is superior to nylon 6. When the tire is vulcanized, it is subjected to heat and tension, and these performance differences are more obvious, resulting in differences in tire size and performance. Usually, in the industry, means such as adjusting the length and angle of the tire cord and pre-stretching during molding can be adopted to achieve similar performance effects, but this method often has a long R & D cycle and high R & D costs. Therefore, it is necessary to propose a solution to solve the above existing problems. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above deficiencies in the prior art and provide a nylon cord and a tire prepared therefrom.

[0004] To solve the above technical problems, the present invention provides a nylon cord, which at least includes two strands of nylon 6 filaments. Each strand of nylon 6 filaments is first subjected to Z-direction initial twisting to form a ply yarn, and each ply yarn is combined and subjected to S-direction doubling twisting in the opposite direction to the initial twisting direction to form a nylon cord;

[0005] The specification of the nylon cord is any one of 840D / 2, 1260D / 2, and 1890D / 2;

[0006] The initial twisting turns of the nylon 6 filaments are 5% - 50% lower than those of the traditional nylon 6 filaments of the same specification; the twisting angle of the nylon 6 filaments is 1° - 6° lower than that of the traditional nylon 6 filaments of the same specification;

[0007] The doubling twisting turns of the nylon 6 ply yarns are 5% - 50% lower than those of the traditional nylon 6 ply yarns of the same specification; the doubling twisting angle of the nylon 6 ply yarns is 2° - 12° lower than that of the traditional nylon 6 ply yarns of the same specification;

[0008] The density of the nylon 6 filaments is 7D - 12D.

[0009] It should be noted that for the nylon cord provided by the present invention, on the one hand, the twist number of its silk threads is lower than that of traditional nylon 6 cord silk threads, resulting in a lower initial twist angle of the silk threads; on the other hand, the linear density (weight per unit length) of its silk threads is higher than that of traditional nylon 6 cord, making the twist angle decrease faster during tensile deformation of the cord. At the same time, due to the reduction in the number of silk threads, not only can the stress on the silk threads be more uniform and less likely to break, but also the gap between the plies can be increased, greatly improving the rubber penetration performance. The regulation of the above two factors, namely the twist number and the linear density of the silk threads, has a synergistic effect, significantly increasing the modulus of the nylon 6 cord and significantly improving its performance in terms of elongation at constant load, hot air shrinkage, etc., overcoming the problems of poor tire size stability and performance of nylon 6.

[0010] In a more preferred embodiment, the initial twist number of the nylon 6 silk threads is 18% - 40% lower than that of traditional nylon 6 silk threads of the same specification; the twist angle of the nylon 6 silk threads is 2° - 5° lower than that of traditional nylon 6 silk threads of the same specification.

[0011] In a more preferred embodiment, the double twist number of the nylon 6 plies is 18% - 40% lower than that of traditional nylon 6 plies of the same specification; the double twist angle of the nylon 6 plies is 4° - 9° lower than that of traditional nylon 6 plies of the same specification.

[0012] In a more preferred embodiment, the density of the nylon 6 silk threads is 8D - 10D.

[0013] In a more preferred embodiment, the specification of the nylon cord is 840D / 2; the initial twist number of the nylon cord is 300 - 380 twists / meter, the double twist number is 300 - 380 twists / meter, the twist angle of the silk threads is 7.5° - 10°, and the twist angle of the plies is 15.5° - 20°.

[0014] In a more preferred embodiment, the specification of the nylon cord is 1260D / 2; the initial twist number of the nylon cord is 230 - 305 twists / meter, the double twist number is 230 - 305 twists / meter, the twist angle of the silk threads is 7.5° - 10°, and the twist angle of the plies is 15.5° - 20°.

[0015] In a more preferred embodiment, the specification of the nylon cord is 1890D / 2; the initial twist number of the nylon cord is 190 - 260 twists / meter, the double twist number is 190 - 260 twists / meter, the twist angle of the silk threads is 7.0° - 10°, and the twist angle of the plies is 14.5° - 20°.

[0016] The present invention provides a tire using the nylon cord as described above.

[0017] In summary, the present application includes at least one of the following beneficial technical effects:

[0018] The invention provides a high-performance nylon 6 cord. The physical properties and dimensional stability of the tire prepared by using it are closer to those of nylon 66 cord, breaking the limitation of the application of nylon 6 cord in tires due to its poor performance and dimensional stability. It can achieve the purpose of reducing costs while maintaining the performance of the tire.

[0019] Other features and beneficial effects of the present invention will be described in the subsequent specification, and, in part, will become apparent from the specification or will be understood by implementing the present invention. The objectives and other beneficial effects of the present invention can be achieved and obtained by the structures and / or components pointed out in the specification and claims. Detailed implementation manners

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments; as long as the technical features designed in different implementation manners of the present invention described below do not conflict with each other, they can be combined with each other; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that all terms (including technical terms and scientific terms) used in the present invention have the same meanings as those generally understood by those of ordinary skill in the technical field to which the present invention belongs, and should not be construed as a limitation to the present invention; it should be further understood that the terms used in the present invention should be understood as having meanings consistent with their meanings in the context of this specification and the relevant technical field, and should not be understood in an idealized or overly formal sense, unless clearly defined as such in the present invention.

[0022] It should be noted that the "initial twist number" of the "conventional nylon 6 filament of the same specification", the "initial twist angle" of the "conventional nylon 6 filament of the same specification", the "double twist number" of the "conventional nylon 6 ply yarn of the same specification", and the "double twist angle" of the "conventional nylon 6 ply yarn of the same specification" mentioned in the present invention. The above "twist number" and "twist angle" are the numerical ranges of the twist numbers and twist angles of the filaments and ply yarns of nylon 6 material under the corresponding specifications in this industry. Reference can be made to Table 3, Performance Items and Index Values (Type B) of Nylon 6 Dipped Cord Fabric in GB / T9102-2016. Those skilled in the art know their specific meanings, so no further elaboration will be made.

[0023] The technical solutions of the present invention will be further described and illustrated through specific examples and comparative examples below.

[0024]

Preparation of specimens

[0025] Prepare samples according to the implementation parameters of each example and comparative example provided in Table 1.

[0026] Table 1 Parameter Table of Each Example

[0027]

[0028]

[0029] Table 2 Parameter Table of Each Comparative Example

[0030] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Specification 1260D / 2-25 1260D / 2-25 1260D / 2-25 1260D / 2-25 Material Nylon 66 Nylon 6 Nylon 6 Nylon 6 Original yarn density D (g / 9000m) 6 6 9 6 Cord density D (g / 9000m) 2520 2520 2520 2520 Initial twist number (twists / m) 375 375 375 270 Yarn twist angle (°) 12.2 12.2 12.2 8.9 Final twist number (twists / m) 375 375 375 270 Strand twist angle (°) 24.5 24.5 24.5 17.9 Cord diameter mm 0.65 0.65 0.65 0.65

[0031]

Preparation of Test Cord

[0032] The manufacturing process of the cord includes the following steps:

[0033] Steps such as raw silk salt treatment, raw silk polymerization, raw silk spinning, cooling, stretching, heat setting, twisting and weaving, dipping, etc.;

[0034] Among them, in the raw silk spinning process step, the raw yarn density is controlled by spinnerets with different numbers of holes F. The number of holes in the spinneret (F) = weight of 9000 meters of raw yarn / raw yarn density. Therefore, if the weight of 9000 meters of raw yarn is 1260 g, then the cord density of 6 D corresponds to a spinneret of 210 F, the cord density of 8 D corresponds to a spinneret of 158 F, 9 D corresponds to a spinneret of 140 F, 10 D corresponds to a spinneret of 126 F, and so on; it should be noted that the twisting and weaving process step is to control relevant parameters according to the data in Tables 1 and 2. If there is no special instruction for others, the process method steps are the same as the existing processes in the art.

[0035]

Preparation of Test Tires

[0036] After sizing the above-mentioned test cord according to the conventional production process, prepare tires of the T125 / 70D16 96M specification.

[0037]

Performance Testing

[0038] Size the nylon cords prepared in the examples and comparative examples to prepare tires and conduct the following tests:

[0039] 1. Breaking strength: Test the cord according to GB / T 9102. The higher the value, the better the cord strength;

[0040] 2. Elongation at constant load: Test the cord according to GB / T 9102. The lower the value, the greater the cord modulus.

[0041] 3. Heat shrinkage: Test the cord yarn according to GB / T 30312. The lower the value, the better the thermal stability of the cord

[0042] 4. Dimensional stability, calculated by the elongation at a fixed load of the cord + heat shrinkage. The lower the value, the more stable the cord dimensions.

[0043] 5. Yarn-to-yarn adhesion strength: Test the semi-finished cord fabric according to GB / T 532. The higher the value, the better the adhesion strength.

[0044] 6. Tire outer diameter (uninflated): Test the tire outer diameter according to GB / T521, and the result is expressed as a relative value. The larger the value, the better the tire dimensional stability.

[0045] 7. Tire outer diameter (at standard pressure): Test the tire outer diameter according to GB / T521, and the result is expressed as a relative value. The smaller the value, the better the tire dimensional stability.

[0046] 8. High-speed and durability performance of the tire:

[0047] High-speed performance conditions: Test and observe the damage of the tire under the conditions of a load of 1030 Kg, a speed of 130 km / h, and a time of 10 min;

[0048] Durability performance conditions: Test and observe the damage of the tire under the conditions of a load of 710 Kg, a speed of 80 km / h, and a time of 24 h.

[0049]

Performance test results

[0050] Table 3 Performance test table of samples of each example

[0051] Example 1 Example 2 Example 3 Example 4 Example 5 Breaking strength N 213 205 220 210 215 Elongation at a constant load of 66.7N % 8.3 8.2 8.2 8.0 7.9 Hot air shrinkage % 4.7 4.2 4.6 4.4 4.0 Dimensional stability % 13.0 12.4 12.8 12.4 11.9 Yarn-to-yarn adhesion strength 195 190 226 216 198 Tire outer diameter (uninflated) / % 95 99 96 97 100 Tire outer diameter (at standard pressure) / % 103 102 103 101 101 High-speed performance Not damaged Not damaged Not damaged Not damaged Not damaged Durability performance Not damaged Not damaged Not damaged Not damaged Not damaged

[0052] Table 4 Performance test table of samples of each comparative example

[0053] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Breaking strength N 208 220 215 214 Elongation at a constant load of 66.7N % 7.8 8.8 8.6 8.4 Hot air shrinkage % 3.8 5.0 4.8 4.7 Dimensional stability % 11.6 13.8 13.4 13.1 Yarn-to-yarn adhesion strength 185 180 200 183 Tire outer diameter (uninflated) / % 100 90 93 94 Tire outer diameter (at standard pressure) / % 100 105 104 104 High-speed performance Not damaged Not damaged Not damaged Not damaged Durability performance Not damaged Not damaged Not damaged Not damaged

[0054] As can be seen from Table 3 and Table 4, compared with Comparative Example 2, although the breaking strength of Examples 1-5 decreased slightly, the effect was not much different from that of the nylon 66 raw yarn used in Comparative Example 1, and still could meet the usage requirements. Moreover, compared with Comparative Example 2, Comparative Example 3 only increased the density, and Comparative Example 4 only decreased the twist angle, and neither of them could achieve good effects.

[0055] The elongation at a fixed load, heat shrinkage, and dimensional stability of the cords of Examples 1-5 were significantly improved. Among them, the dimensional stability was improved by 6% - 16% compared with Comparative Example 2, and Example 5 was the best. It can be seen that the cord and tire dimensional stability of Examples 1-5 were significantly improved compared with Comparative Example 2, and were comparable to those of the nylon 66 raw yarn used in Comparative Example 1;

[0056] Comparing Comparative Example 3, Comparative Example 4 with Examples 1 to 5 in each item, it can be seen that the simultaneous regulation of twist, twist angle and linear density can achieve a synergistic effect. Only regulating a single factor cannot achieve the effect of the present invention.

[0057] The comparison results of the yarn-to-yarn adhesion strength item show that the greater the linear density, the greater the yarn-to-yarn adhesion strength. This may be because the decrease in the number of silk threads leads to an increase in the gap between the stranded ropes, greatly improving the glue penetration performance. The comparison results of the high speed and durability of the tire show that each example and comparative example can meet the enterprise standard requirements. Therefore, the examples of the present invention can achieve the purpose of reducing costs by using nylon 6 instead of nylon 66 without affecting the dimensional stability and performance of the tire.

[0058] In addition, those skilled in the art should understand that although there are many problems in the prior art, each example or technical solution of the present invention can be improved in only one or several aspects, and it is not necessary to solve all the technical problems listed in the prior art or the background art at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be regarded as a limitation to that claim.

[0059] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some or all of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the examples of the present invention.

Claims

1. A nylon cord, characterized in that, It includes at least two strands of nylon 6 silk threads. Each strand of nylon 6 silk thread is first subjected to Z-direction initial twisting to form a ply yarn, and each ply yarn is plied and subjected to S-direction doubling twisting in the opposite direction of the initial twisting to form a nylon cord; the specification of the nylon cord is any one of 840D / 2, 1260D / 2, and 1890D / 2; the density of the nylon 6 silk thread is 7D to 12D; the specification of the nylon cord is 840D / 2; the initial twisting count of the nylon cord is 300 to 380 twists per meter, the doubling twisting count is 300 to 380 twists per meter, the silk thread twist angle is 7.5° to 10°, and the ply yarn twist angle is 15.5° to 20°; the specification of the nylon cord is 1260D / 2; the initial twisting count of the nylon cord is 230 to 305 twists per meter, the doubling twisting count is 230 to 305 twists per meter, the silk thread twist angle is 7.5° to 10°, and the ply yarn twist angle is 15.5° to 20°; the specification of the nylon cord is 1890D / 2; the initial twisting count of the nylon cord is 190 to 260 twists per meter, the doubling twisting count is 190 to 260 twists per meter, the silk thread twist angle is 7.0° to 10°, and the ply yarn twist angle is 14.5° to 20°.

2. The nylon cord according to claim 1, wherein: The density of the nylon 6 silk thread is 8D to 10D.

3. A tire using the nylon cord according to claim 1 or 2.

Images