braided yarn

Abstract

A braided yarn with a CNT core and excellent tensile strength and scratch resistance is provided. The braided yarn is formed by winding multiple monofilaments or multifilaments around a core yarn containing linear CNT (carbon nanotube) yarn. The yarn-making angle between the core yarn and the sheath yarn is 3 degrees or more and 15 degrees or less.

Description

Technical Field

[0001] This invention relates to braided yarn with excellent tensile strength and scratch resistance. Background Technology

[0002] In the past, braided yarns with various properties were provided according to their uses and purposes.

[0003] For example, monofilaments of polyamide resins such as nylon 6 and nylon 6,6, fluorinated resins such as polyvinylidene fluoride, polyester resins such as polyethylene terephthalate, and polyolefin resins such as ultra-high molecular weight polyethylene are widely used as fishing lines, depending on the target fish and fishing method (see Patent Document 1).

[0004] Furthermore, multifilament (PE) lines, made from polyethylene fibers, are now widely used as fishing lines. PE lines have superior tensile strength (linear strength), low elongation, and small cross-sectional area compared to the monofilaments formed from synthetic resins. On the other hand, PE lines have poorer scratch resistance (abrasion resistance) compared to these monofilaments.

[0005] As a raw material with excellent scratch resistance, there are CNT yarns (see Patent Documents 2 to 4) that bundle carbon nanotubes (hereinafter referred to as CNTs), which are one of the carbon-based microstructures. However, CNT yarns have lower tensile strength compared to PE yarns.

[0006] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 2741841 Patent Document 2: Japanese Patent No. 5350635 Patent Document 3: Japanese Patent No. 4512750 Patent Document 4: Japanese Patent No. 7192176 Summary of the Invention

[0007] The problem that the invention aims to solve Previously, lines with excellent properties in either tensile strength (linear strength) or scratch resistance (abrasion resistance) have been developed, but lines that combine both tensile strength and scratch resistance have not yet been developed. The aim is to provide a line that maintains the excellent properties of PE lines, which are widely used as fishing lines, while improving scratch resistance.

[0008] The present invention is mainly intended to solve the technical problem of providing a braided yarn with CNT core wires that has excellent tensile strength and scratch resistance.

[0009] Solution for solving the problem According to one embodiment, the braided yarn is a braided yarn formed by winding multiple monofilaments or multifilaments around a core yarn comprising linear CNT yarns made of CNTs (carbon nanotubes), wherein the yarn-making angle formed by the core yarn and the sheath yarn is more than 3 degrees and less than 15 degrees.

[0010] According to one embodiment, the coefficient of variation of the cross-sectional area of ​​the plurality of sheath wires is less than 10%, and the plurality of sheath wires are formed of the same or equivalent material, and the wire-making angle formed by the core wire and the sheath wire is more than 5 degrees and less than 15 degrees.

[0011] According to one embodiment, the ratio of the cross-sectional area of ​​the core wire to the cross-sectional area of ​​the braided wire is 38% or more, and the number of sheath wires is 3 or more and 24 or less.

[0012] According to one embodiment, the number of sheath threads is 7 or more and 24 or less.

[0013] According to one embodiment, the braided thread, with a counterweight fixed at the front end, is placed on a file and repeatedly reciprocated in a certain direction until it breaks, the number of reciprocations required, i.e., the number of durability cycles, is more than 250.

[0014] Invention Effects According to the present invention, a braided yarn with CNT core wires that has excellent tensile strength and scratch resistance can be provided. Attached Figure Description

[0015] Figure 1 This is a schematic diagram showing the structure of the braided thread 100.

[0016] Figure 2 This is a graph representing the evaluation results (breaking load ratio) of the tensile strength of braided yarn 100.

[0017] Figure 3 It is a graph representing the evaluation results of the tensile strength of braided yarn 100 (the breaking load ratio per unit cross-sectional area).

[0018] Figure 4 This is a schematic diagram illustrating the evaluation method for the scratch resistance of braided yarn 100.

[0019] Figure 5 This is a chart representing the evaluation results (durability cycle ratio) of the scratch resistance of braided yarn 100.

[0020] Figure 6 This is a diagram illustrating the cross-sectional area of ​​the braided yarn.

[0021] Figure 7 This is a diagram illustrating the angle of the control line. Detailed Implementation

[0022] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0023] <Core Wire> The braided yarn of the present invention has a core yarn comprising CNT yarn.

[0024] CNT yarn is a thread made by bundling CNTs together. When CNTs are made into CNT yarn, as the generated CNTs are pulled out, they are oriented in the direction they are pulled out and attract each other through the attraction between the individual CNTs to form a continuous thread. Therefore, CNT yarn can be obtained by winding it.

[0025] Various CNTs exist in their structure as single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), with multi-walled CNTs also known to have three or more layers. Any type of CNT can be used when manufacturing CNT yarns.

[0026] The average diameter of each CNT constituting the CNT yarn is preferably 3 to 15 nm, more preferably 7.5 to 15 nm. The length of the CNT is preferably 50 μm or more, more preferably 100 μm or more. This is because if the average length of the CNT is shorter than 50 μm, the number of ends between the individual CNTs will increase. The average diameter and average length of the CNT can be determined by averaging the diameter and length of a plurality of arbitrarily selected CNTs using a transmission electron microscope.

[0027] The diameter (wire diameter) of the CNT yarn, which is an aggregate of individual CNTs, is 20μm to 70μm, preferably 25μm to 60μm, and more preferably 30 to 50μm.

[0028] The length of CNT yarn can be set to a preferred length depending on the intended use. For example, when used as the core of a braided line for fishing lines, it can be set to 100m to 300m. Of course, it can also be set to a length shorter than 100m. In addition, it can be set to a length of more than 300m if necessary.

[0029] The CNT yarn constituting the core thread can be a single CNT web spun into a thread, or it can be composed of multiple CNT yarns combined, or multiple CNT yarns twisted together. Preferably, the braided yarn of the present invention uses a yarn made by bundling multiple untwisted CNT yarns as the core thread. This improves the tensile strength of the core thread. The core thread can also be made by bundling or twisting CNT yarns with other fibers.

[0030] <Sheath> The braided yarn of the embodiments of the present invention has a sheath yarn containing fibers with excellent tensile strength, such as UHMW-PE (Ultra-high Molecular Weight Polyethylene).

[0031] UHMW-PE used as sheath thread is preferably 10T to 440T in thickness. Here, T: texels refers to the unit of fiber thickness expressed in terms of weight per unit length. The thickness of fiber weighing 1g per 10,000m length is expressed as 1T (texels).

[0032] In addition to UHMW-PE, the raw materials for sheathing can also be synthetic resin filaments such as nylon and fluorocarbon. However, in this case, the number and thickness of the sheathing can be adjusted in a way that ensures the necessary tensile strength and flexibility.

[0033] <Methods for making braided yarn> Figure 1 This is a schematic diagram illustrating the structure of the braided yarn 100 according to an embodiment of the present invention. When the braided yarn 100 is manufactured, one or more UHMW-PE yarns are wound or woven into the core yarn 101 containing CNT yarns as sheath yarns 102.

[0034] The sheath 102 can be a spiral wound of one or more braided threads around the core 101, or it can be a braided multiple threads covering the core 101. To improve the tensile strength of the braided thread 100, it is ideal to braid multiple threads rather than a spiral wound of the sheath 102 around the core 101.

[0035] When multiple sheath threads 102 are braided around the core thread 101, it is easier to manufacture the yarn if the thickness of each sheath thread 102 is approximately the same, and the contact between the core thread 101 and the sheath thread 102 becomes more stable. Specifically, it is preferable to control the non-uniformity of the cross-sectional area of ​​the multiple sheath threads 102 used for braiding the yarn 100 to within a coefficient of variation (CV) of 10%. CV is an indicator that represents the degree of non-uniformity relative to the average value, and can be calculated using the following formula.

[0036] CV (%) = Standard deviation ÷ Mean × 100 The use of the same or equivalent material for each of the multiple sheath wires 102 makes wire fabrication easier, and the contact between the core wire 101 and the sheath wire 102 becomes easier and more stable.

[0037] Furthermore, the more sheath threads 102 there are, the fewer unevennesses on the outer surface of the braided thread 100, resulting in a smoother surface. The core thread 101 is also secured from all directions, and its uniform contraction leads to an excellent balance between tensile strength and scratch resistance. From the viewpoint of ensuring tensile strength, the number of sheath threads 102 is preferably 3 or more; from the viewpoint of ensuring scratch resistance, the number of sheath threads 102 is preferably 7 or more; and from the viewpoint of ensuring flexibility, the number of sheath threads 102 is preferably 24 or less. It should be noted that the bending method of the braided thread 100 can be changed by making the thickness of one or more sheath threads 102 different from the other sheath threads 102. Alternatively, the characteristics of the braided thread 100 can be appropriately altered by making the raw material of one or more sheath threads 102 different from the other sheath threads 102.

[0038] <Tensile Strength Evaluation Test 1> The tensile strength of the braided yarn of the present invention was evaluated. In this experiment, in order to evaluate the effect of the core yarn material on the tensile strength, the tensile strengths of four examples (Examples 1 to 4) with CNT yarn as the core yarn and UHMW-PE (hereinafter also referred to as PE material) as the sheath yarn, two comparative examples (Comparative Example 3 and Comparative Example 4), and two comparative examples (Comparative Example 1 and Comparative Example 2) with PE material as both the core yarn and the sheath yarn were measured and compared. In addition, in order to evaluate the effect of the ratio of the cross-sectional area of ​​the core yarn to the cross-sectional area of ​​the braided yarn on the tensile strength, braided yarns with a core yarn cross-sectional area ratio of 38% and 60% were made with CNT yarn as the core yarn and PE material as the core yarn, respectively, and the tensile strengths were compared.

[0039] Table 1 shows the thickness of the braided yarn and the ratio of the cross-sectional area of ​​the core wire to the cross-sectional area of ​​the braided yarn in Examples 1 and 2, and Comparative Examples 1 and 2. Here, the cross-sectional area of ​​the braided yarn refers to the cross-sectional area of ​​the braided yarn, assuming it is approximately cylindrical. Figure 6 The oblique part) is approximately a circle with a diameter of R1. Figure 6 When represented by a dashed line, it is set as the area of ​​the circle. It should be noted that this does not represent the actual area of ​​the core and sheath wires in the cross-section of the braided yarn. Figure 6 (The total area of ​​the sloping portion). Similarly, the cross-sectional area of ​​the core wire refers to the area of ​​a circle with a diameter of R2, approximating the cross-section of the core wire as approximately cylindrical.

[0040] In both Example 1 and Comparative Example 1, the braided wire thickness was set to 0.20 mm (equivalent to size 1), and the ratio of the core wire cross-sectional area to the braided wire cross-sectional area was 38%. In both Example 2 and Comparative Example 2, the braided wire thickness was set to 0.12 mm (equivalent to size 0.7), and the ratio of the core wire cross-sectional area to the braided wire cross-sectional area was 60%. Table 2 shows the breaking load, breaking load ratio, breaking load per unit cross-sectional area, and breaking load ratio per unit cross-sectional area when tensile load is applied in the long dimension of these braided yarns. Here, the breaking load ratio is the ratio of breaking loads when the breaking load of Comparative Example 2 is set to 1. The breaking load ratio per unit cross-sectional area is the ratio of breaking loads per unit cross-sectional area when the breaking load per unit cross-sectional area of ​​Comparative Example 1 is set to 1. Figure 2 This is a chart plotted based on the breaking load ratio. It can be seen that Example 1, with the core yarn set to CNT yarn, has a higher breaking load ratio compared to Comparative Example 1, which uses PE material as the core yarn under the same conditions (same thickness, core yarn cross-sectional area ratio to braided yarn cross-sectional area). Similarly, Example 2 has a higher breaking load ratio compared to Comparative Example 2 under the same conditions.

[0041] Figure 3 This is a chart plotted to show the breaking load ratio per unit cross-sectional area. It can be seen that, compared to Comparative Examples 1 and 2 where the core yarn is made of PE material, the breaking load ratio per unit cross-sectional area is larger in Examples 1 and 2 where the core yarn is made of CNT yarn.

[0042] Therefore, braided yarns with CNT core yarns can be evaluated as superior in tensile strength to braided yarns with PE core yarns. Furthermore, this evaluation is appropriate regardless of the yarn thickness or the ratio of the core yarn's cross-sectional area to the braided yarn's cross-sectional area.

[0043] <Tensile Strength Evaluation Test 2> In this experiment, the effect of the braiding angle of the yarn on the tensile strength was evaluated. The braiding angle refers to... Figure 7 As shown, when the braided yarn is viewed from the side, the smaller value of θ is the angle between the sheath (colored part) and the core yarn.

[0044] As shown in Table 3, in this experiment, the tensile strength of two embodiments (Example 3 and Example 4) with CNT yarn as the core and PE material as the sheath, two comparative examples (Comparative Example 3 and Comparative Example 4), one comparative example (Comparative Example 2) with PE material as both the core and sheath, and a commercially available PE yarn of 0.6 (Reference Example 4) were measured and compared. Examples 3, 4, 2, 3, and 4 were all manufactured to the same thickness of approximately 0.6 as Reference Example 4.

[0045] Table 3 shows the breaking load, breaking load ratio, breaking load per unit cross-sectional area, and breaking load ratio per unit cross-sectional area when tensile load is applied in the long dimension of these braided yarns. When comparing Example 3 and Comparative Example 2, it was found that, with the same yarn angle of 10 degrees, the breaking load per unit cross-sectional area increased by 1.48 times compared to the case where the core yarn was made of PE material, resulting in higher tensile strength. Furthermore, when comparing Example 3, Example 4, Comparative Example 3, and Comparative Example 4, it was found that, with the same CNT yarn core, a smaller yarn angle resulted in a larger breaking load per unit cross-sectional area and higher tensile strength.

[0046] Therefore, for braided yarns with CNT core yarns, if the yarn-making angle is the same, they can be evaluated as having superior tensile strength compared to braided yarns with PE core yarns. Furthermore, for braided yarns with CNT core yarns, the smaller the yarn-making angle, the higher the tensile strength.

[0047] It should be noted that the inventors conducted repeated and in-depth experiments, and the results showed that, from a manufacturing perspective, it is preferable to set the lower limit of the wire-making angle to 3 degrees, as this makes it less likely for the core wire to fly out of the sheath wire. It should also be noted that, from a manufacturing stability perspective, it is more preferable to set the lower limit of the wire-making angle to 5 degrees.

[0048] <Scratch Resistance Evaluation 1> To evaluate the scratch resistance of the braided yarn of the present invention, the scratch resistance of an example with a CNT yarn core and a PE material sheath, and a comparative example with a PE material core and a PE material sheath, were measured and compared using the following method. Furthermore, for reference, commercially available multifilament PE yarn, monofilament nylon yarn, and fluorocarbon yarn were measured using the same method.

[0049] use Figure 4The specific testing methods are explained below. 1 is the reciprocating motion body. In this test, the reciprocating motion body 1 is an A&D STB1225s tensile and compression testing machine (reciprocating motion body speed: 200 mm / min, stroke: 5 mm, number of reciprocations per cycle: 100, force sensor: 500 kg, chuck clamp: tire cord pneumatic chuck). 2 is the load. In this test, a teardrop-shaped counterweight (No. 20, 75 g) is used. 3 is the test object (braided thread). 4 is the friction body. In this test, a paper file (#240) is used.

[0050] One end of the test object 3 is fixed to the reciprocating motion body 1, and the other end is fixed to the counterweight 2. The reciprocating motion body 1 is used to make the test object 3 travel back and forth, making contact with the friction body 4 at approximately right angles along the path. The number of reciprocations required for the test object 3 to break is defined as the number of durability cycles.

[0051] Table 4 shows the thickness of the wires used as test subjects. In Example 1 and Comparative Example 1, the thickness of the braided wire was set to 0.20 mm, and the ratio of the cross-sectional area of ​​the core wire to the cross-sectional area of ​​the braided wire was 38%. As Reference Examples 1 to 3, PE wire, nylon wire, and fluorocarbon wire (all commercially available products) with a thickness of about 0.20 mm were prepared. Table 5 shows the results. Figure 4 The table shows the number of durability cycles and the durability cycle ratio when these lines are scratched using the method shown. Here, the durability cycle ratio is the ratio of the number of durability cycles when the durability cycle of Comparative Example 1 is set to 1. Figure 5 This is a chart showing the ratio of durability cycles. Example 1, which uses CNT yarn as the core thread, has 11.9 times more durability cycles than Comparative Example 1, which uses PE material as the core thread (same thickness, same ratio of core thread cross-sectional area to braided yarn cross-sectional area). It should be noted that Reference Example 1 (PE yarn No. 1.0) has 1.9 times more durability cycles than Comparative Example 1, Reference Example 2 (Nylon yarn No. 1.5) has 6.6 times more than Comparative Example 1, and Reference Example 3 (Fluorocarbon yarn No. 1.5) has 8.5 times more durability cycles than Comparative Example 1. The reason why the durability cycles of Reference Example 1 (PE yarn No. 1.0) are considered to exceed those of Comparative Example 1, which uses only PE material, is that in Reference Example 1, which is a commercially available product, the durability cycles of the PE yarn were improved by employing yarn-making / coating techniques.

[0052] Therefore, braided yarn with CNT yarn as the core can be evaluated as overwhelmingly superior in scratch resistance compared to braided yarn with PE material as the core. It should be noted that even compared to the monofilament yarns of Reference Examples 2 and 3, which are generally considered to have excellent scratch resistance, the braided yarn with CNT yarn as the core exhibits extremely superior scratch resistance.

[0053] The reasoning is as follows: CNT yarns are bonded together by intermolecular forces. Therefore, the CNTs on the outer periphery of the core yarn detach from the CNT yarn due to friction, but since the CNTs are bonded together by intermolecular forces, fuzzing gradually forms on the outer periphery of the core yarn. It can be assumed that this fuzzing of the CNTs acts as a coating to reduce friction on the inner side of the core yarn.

[0054] <Scratch Resistance Evaluation 2> In this experiment, the effect of the braiding angle of the braided yarn on its scratch resistance was evaluated.

[0055] The test specimens used in Table 6 are the same as those shown in Table 2. Specifically, the scratch resistance of two examples (Example 3 and Example 4) with a core yarn made of CNT yarn and a sheath made of PE material, two comparative examples (Comparative Example 3 and Comparative Example 4), one comparative example (Comparative Example 2) with a core yarn made of PE material and a sheath made of PE material, and a commercially available PE yarn of 0.6 (Reference Example 4) were measured and compared. Examples 3, 4, 2, 3, and 4 were all manufactured to the same thickness of approximately 0.6 as Reference Example 4.

[0056] Table 6 shows the results of the same scratch test performed using these braided yarns as in <Evaluation of Scratch Resistance 1>. Figure 4 The table shows the number of durability cycles and the durability cycle ratio under the condition that the durability cycle of Comparative Example 3 is set to 1. Here, the durability cycle ratio is the ratio of the number of durability cycles when the durability cycle of Comparative Example 3 is set to 1. When comparing Example 3 and Comparative Example 2, it was found that, with the same yarn angle of 10 degrees, the durability cycle ratio increased by 59.6 times compared to the case where the core yarn was made of PE material, indicating a significant improvement in scratch resistance. Furthermore, when comparing Example 3, Example 4, Comparative Example 3, and Comparative Example 4, it was found that, with the same CNT yarn core, a smaller yarn angle resulted in a higher durability cycle ratio and improved scratch resistance.

[0057] Therefore, for braided yarns with CNT core yarns, if the yarn-making angle is the same, they can be evaluated as having superior scratch resistance compared to braided yarns with PE core yarns. Furthermore, for braided yarns with CNT core yarns, the smaller the yarn-making angle, the better the scratch resistance.

[0058] It should be noted that, from the perspective of ensuring practical scratch resistance, the upper limit of the thread-making angle of the braided yarn with CNT yarn as the core is preferably set to about 15 degrees. This is because if the thread-making angle is less than 15 degrees, it can ensure more than twice the durability of the fluorocarbon yarn No. 1.5 in Reference Example 3 (about 180 times), thus fully utilizing the advantages of the braided yarn with CNT yarn as the core.

[0059] According to this embodiment, the braided yarn with CNT yarn as the core and PE material as the sheath has superior tensile strength compared to the braided yarn with PE material as the core. Furthermore, it exhibits overwhelmingly superior scratch resistance compared to the braided yarn with PE material as the core.

[0060] It should be noted that, within the scope of this invention, various embodiments can be freely combined, or any constituent elements of each embodiment can be modified, or any constituent elements can be omitted in each embodiment.

[0061] For example, in the above embodiments, the braided line of the present invention is mainly shown as a fishing line, but the present invention is not limited thereto and can be applied to various applications requiring both tensile strength and scratch resistance. For example, the present invention can be applied to clothing and protective gear with excellent tensile strength and scratch resistance due to its use as a textile fiber, parts or components of vehicles / ships and aircraft, building and civil engineering materials, parachutes / tents / sails, interior decorations including curtains and wall hangings, etc. Furthermore, by twisting or combining one or more braided lines, the present invention can be applied to nets / ropes / fishing nets / kite lines / fishing tackle, sporting goods including rackets, and other thread materials.

[0062] Furthermore, while the above embodiments primarily illustrate an example using PE material as the raw material for the sheath, the present invention is not limited to this, and other raw materials may also be used for the sheath. In this case, it is considered that the tensile strength of the braided yarn mainly depends on the sheath, therefore, it is preferable to use a raw material with excellent tensile strength for the sheath. It should be noted that the scratch resistance of the braided yarn is considered a characteristic primarily guaranteed by the core material of the CNT yarn; therefore, even if materials other than PE are used for the sheath, overwhelming scratch resistance is still exhibited.

[0063] Explanation of reference numerals in the attached figures 100: Braided thread; 101: Core thread; 102: Sheath thread; 1: Reciprocating motion body; 2: Load; 3: Braided thread; 4: Friction body.

Claims

1. A braided yarn comprising a core yarn containing linear CNT yarns made of carbon nanotubes (CNTs) wound with a sheath of multiple monofilaments or multifilaments, wherein, The wire-making angle formed by the core wire and the sheath wire is more than 3 degrees and less than 15 degrees.

2. The braided yarn according to claim 1, wherein, The coefficient of variation of the cross-sectional area of ​​the plurality of sheaths is less than 10%, and the plurality of sheaths are formed of the same or equivalent material. The wire-making angle between the core wire and the sheath wire is more than 5 degrees and less than 15 degrees.

3. The braided yarn according to claim 1, wherein, The ratio of the cross-sectional area of ​​the core wire to the cross-sectional area of ​​the braided wire is 38% or more. The number of sheaths is between 3 and 24.

4. The braided yarn according to claim 1, wherein, The number of sheaths is between 7 and 24.

5. The braided yarn according to claim 1, wherein, When the braided thread with a counterweight fixed at the front end is placed on a file and repeatedly reciprocated in a certain direction, the number of reciprocations required until it breaks, i.e., the number of durability cycles, is more than 250.

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