Double-rope structure

Abstract

Provided is a double-rope structure constituted of an inner core and an outer envelope. In the double-rope structure, the inner core comprises a high-strength / high-elasticity fiber of 20 cN / dtex or greater in yarn strength and 400 cN / dtex or greater in yarn elasticity, and inner outer layer properness represented by the following formula (1) is from 0.70 to 1.20.　(1): (a2 / b2) / Vf × 100 In the formula (1), a represents a diameter of an outer circumference of the inner core, b represents a diameter of an outer circumference of the outer envelope, and Vf represents a volume ratio (%) of the inner core to the total volume of the inner core and the outer envelope.

Description

Double rope structure Related Applications

[0001] This application claims priority to Japanese Patent Application No. 2022-101743, filed on June 24, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a double rope structure consisting of an inner core (inner layer) and an outer skin (outer layer).

[0003] Ropes are made by twisting or braiding many strands into a rope or string shape, and are used for water applications such as mooring ships and edge ropes for fishing nets, and for land applications such as towing lines and cargo lines. A strand is made up of multiple yarns, and a yarn is formed from multiple single yarns.

[0004] In addition to single-layer rope structures, there are also double-layer rope structures. A double-layer rope structure is formed by arranging twisted or braided strands in the inner core and outer sheath, respectively. For example, Patent Document 1 (Utility Model Registration No. 3199266) discloses a fiber rope having a double structure of a core material and an outer sheath rope covering the outside of the core material, in which the core material is made of high-strength, high-elasticity fiber, and the outer sheath rope is a braided rope made of yarn in which high-strength, high-elasticity fiber and general-purpose fiber are mixed, and the outer sheath rope contains more high-strength, high-elasticity fiber than general-purpose fiber.

[0005] Utility Model Registration No. 3199266

[0006] However, Patent Document 1 proposes that the use of general-purpose fibers and high-strength, high-elasticity fibers in a specific ratio in the outer sheath can address "abrasion," and describes that a better fit between the core material and the outer sheath makes the rope less likely to lose its shape as a whole. However, it also describes that a core material that is not twisted enough and is too soft will be vulnerable to bending and twisting.

[0007] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a double rope structure that is excellent in bending resistance and strength per cross-sectional area.

[0008] As a result of intensive research into achieving the above-mentioned object, the inventors of the present invention have confirmed that when a high-strength, high-elastic modulus fiber is used as the inner core of a double rope structure, the strength of the rope structure can be improved due to the strength characteristics of the high-strength, high-elastic modulus fiber, but on the other hand, they have found that there is room for improvement in the flexibility of the rope structure. As a result of further research, they have unexpectedly found that when an appropriate gap exists between the inner core and the outer skin, the flexibility of the entire rope structure can be improved, and furthermore, the strength per cross-sectional area of ​​the rope structure can be improved, thereby completing the present invention.

[0009] That is, the present invention can be configured in the following aspects: [Aspect 1] A double rope structure configured of an inner core and an outer skin, wherein the inner core is configured of high-strength, high-elasticity fibers having a yarn strength of 20 cN / dtex or more and a yarn elastic modulus of 400 cN / dtex or more, and the inner and outer layer suitability ratio expressed by the following formula (1) is 0.70 to 1.20 (preferably 0.80 to 1.15, more preferably 0.85 to 1.10). (a ２ / b ２) / Vf×100 (1) In formula (1), a represents the diameter of the outer circumference of the inner core, b represents the diameter of the outer circumference of the outer skin, and Vf represents the volume ratio (%) of the inner core to the total volume of the inner core and the outer skin. [Aspect 2] A double rope structure according to aspect 1, wherein the volume ratio Vf of the inner core to the total volume of the inner core and the outer skin is 10% or more (preferably 15% or more, more preferably 20% or more, still more preferably 25% or more; for example, it may be 75% or less, and preferably 70% or less, more preferably 65% ​​or less, still more preferably 60% or less). [Aspect 3] The double rope structure of Aspect 1, wherein the ratio of the average value of the yarn length of the yarn constituting the inner core of the cut portion to the rope length of the cut portion obtained by cutting the double rope structure at a predetermined length, expressed as yarn length / rope length, is 1.005 to 1.400 (preferably 1.005 to 1.200, more preferably 1.006 to 1.180, and even more preferably 1.007 to 1.150). [Aspect 4] The double rope structure according to any one of Aspects 1 to 3, wherein the tensile strength of the double rope structure per cross-sectional area measured in accordance with JIS L 1013:2021 is 180 N / mm ２ or more (preferably 200 N / mm ２ More preferably, 220 N / mm ２A double rope structure having a yarn elongation of 1 to 6% (preferably 2 to 5.5%). [Aspect 5] The double rope structure according to any one of Aspects 1 to 4, wherein the high strength, high elastic modulus fiber has a yarn elongation of 1 to 6% (preferably 2 to 5.5%). [Aspect 6] The double rope structure according to any one of Aspects 1 to 5, wherein the high strength, high elastic modulus fiber is at least one selected from the group consisting of liquid crystal polyester fiber, ultra-high molecular weight polyethylene fiber, aramid fiber, and poly(paraphenylene benzobisoxazole) fiber. [Aspect 7] The double rope structure according to any one of Aspects 1 to 6, wherein the ratio of the strength of the fiber used in the outer shell to the strength of the fiber used in the inner core is 0.10 to 0.40 (preferably 0.12 to 0.35). [Aspect 8] The double rope structure according to any one of Aspects 1 to 7, wherein the outer shell is substantially composed of non-high strength, non-high elastic modulus fibers. [Aspect 9] The double rope structure according to any one of Aspects 1 to 8, wherein the outer sheath is made of multifilament. [Aspect 10] The double rope structure according to any one of Aspects 1 to 9, wherein when a bending test is conducted in which bending is repeated 10,000 times at a bending R of 7.5 mm and a bending angle of 240° under a load of 1% of the tensile breaking strength of the rope, the ratio of the tensile strength of the double rope structure after the bending test to the tensile strength of the double rope structure before the bending test is 90% or more.

[0010] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms "at least one," unless the content clearly dictates otherwise. As used herein, the terms "and / or," "at least one," and "one or more" include any and all combinations of the associated listed items.

[0011] It should be noted that any combination of at least two elements disclosed in the claims and / or the specification and / or the drawings is included in the present invention, and in particular any combination of two or more of the claims set forth in the claims is included in the present invention.

[0012] According to the present invention, a double rope structure is provided in which a high-strength, high-elasticity fiber yarn is used for the inner core and the outer sheath is formed so that an appropriate gap exists between the inner core and the outer sheath, thereby achieving both improved bending resistance and increased strength per cross-sectional area of ​​the rope structure.

[0013] The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and explanation and should not be used to define the scope of the present invention. The scope of the present invention is defined by the appended claims.

[0023] Figure 1 is a conceptual cross-sectional view for explaining a double rope structure according to one embodiment of the present invention. Figure 2 is a schematic exploded side view of a double rope structure according to one embodiment of the present invention. Figure 3 is a schematic perspective view, partially enlarged, of a strand forming the inner core of the double rope structure of Figure 2. Figure 4 is a schematic perspective view for explaining the relationship between the length of one yarn among a plurality of yarns forming the strands of the cut portion of the double rope structure and the length of the cut portion. Figure 5 is a schematic exploded side view of a double rope structure according to another embodiment of the present invention.

[0014] (Double rope structure) The double rope structure is a double rope structure consisting of an inner core and an outer sheath, and a high-strength, high-elasticity fiber yarn is used for the inner core. In the double rope structure, there is an appropriate gap between the high-strength, high-elasticity fiber yarn of the inner core and the outer sheath, so the rope structure as a whole is flexible, and not only can the bending resistance be improved, but the strength per cross-sectional area of ​​the rope structure can also be improved.

[0015] In the double rope structure, the suitability of the inner and outer layers expressed by the following formula (1) is controlled within a predetermined range. ２ / b ２ ) / Vf×100 (1) In formula (1), a represents the outer peripheral diameter (mm) of the inner core, b represents the outer peripheral diameter (mm) of the outer skin, and Vf represents the volume ratio (%) of the inner core to the total volume of the inner core and the outer skin.

[0016] The outer diameter b of the outer sheath is a value measured by clamping the double rope structure 10 with the outer measuring jaws of an electronic caliper. The outer diameter a of the inner core is a value measured by clamping the inner core obtained by removing the outer sheath from the double rope structure with the outer measuring jaws of an electronic caliper. Specifically, these diameters are measured by the method described in the examples below.

[0017] The inner and outer layer suitability ratio is 0.70 to 1.20. If the inner and outer layer suitability ratio is less than 0.70, the outer sheath cannot tighten the inner core rope, resulting in many gaps between the inner core and the outer sheath. If there are many such gaps, the outer sheath will be crushed due to hollow portions generated inside the rope, making it impossible to maintain the strength of the outer sheath and reducing the strength of the entire rope. On the other hand, if the inner and outer layer suitability ratio exceeds 1.20, the inner core will be tightened too much by the outer sheath, resulting in a rope that is very stiff overall and lacks flexibility. Such a rope will suffer severe wear between the fibers each time the rope is deformed, resulting in poor bending resistance. The inner and outer layer suitability ratio may preferably be 0.80 to 1.15, more preferably 0.85 to 1.10. By wrapping and twisting or braiding the rope so that the inner and outer layer suitability ratio is within the above range, an appropriate gap will exist between the inner core and the outer sheath, making the rope structure as a whole more flexible and improving bending resistance.

[0018] The volume ratio Vf of the inner core to the total volume of the inner core and outer skin is the ratio (%) of the total volume occupied by the fibers of the inner core to the total volume occupied by the fibers of the double rope structure in a sample cut to a predetermined length (1.000 m) from the double rope structure. The volume ratio Vf is calculated as follows: (i) After measuring the weight of the sample, it is separated into the outer skin and the inner core, and the weight (g) of each fiber group is measured for each fiber type constituting each, (ii) the weight of each fiber group is calculated based on the specific gravity (g / cm) specific to the fiber type. ３), to calculate the volume of each fiber group, (iii) calculate the volume Vo as the sum of the volumes of each fiber group constituting the outer shell, and the volume Vi as the sum of the volumes of each fiber group constituting the inner core, and (iv) obtain the volume ratio Vf according to the following formula: Vf = (Vi) / (Vi + Vo) x 100. Note that if the outer shell is composed of a single type of fiber, the weight (Wo) of the fiber group constituting the outer shell may be obtained by subtracting the weight (Wi) of the fiber group constituting the inner core from the weight (Wo + Wi) of the sample.

[0019] The volume ratio Vf of the inner core to the total volume of the inner core and outer sheath may be, for example, 10% or more, preferably 15% or more, more preferably 20% or more, and even more preferably 25% or more. When the volume ratio of the inner core is large, the strength of the double rope structure can be improved by using high-strength, high-elasticity fiber yarns. There is no particular upper limit to the volume ratio Vf of the inner core, but from the perspective of improving coverage by the outer sheath, the upper limit of the volume ratio Vf of the inner core may be, for example, 75% or less, preferably 70% or less, more preferably 65% ​​or less, and even more preferably 60% or less.

[0020] Because the double rope structure has excellent bending resistance, when a bending test is performed in which the rope is bent 10,000 times at a bending angle of 240° with a bending radius of 7.5 mm under a load of 1% of the rope's tensile breaking strength, the ratio of the tensile strength of the double rope structure after the bending test to the tensile strength of the double rope structure before the bending test, i.e., the bending retention (%), may be 90% or more, preferably 93% or more, and more preferably 95% or more. The bending retention is a value measured by the method described in the examples below. The upper limit of the bending retention is usually 100%.

[0021] In the double rope structure, the strength per cross-sectional area of ​​the rope structure can be improved, so that the tensile strength per cross-sectional area of ​​the double rope structure measured based on JIS L 1013:2021 is 180 N / mm ２ or more, preferably 200 N / mm ２More preferably, 220 N / mm ２ The upper limit is not particularly limited, but may be, for example, 2000 N / mm ２ may be.

[0022] The present invention will now be described in detail with reference to the following examples: Figure 1 is a conceptual cross-sectional view illustrating a double rope structure.

[0023] As shown in Fig. 1, the double rope structure 10 has an inner core 1 having an outer peripheral diameter a, and an outer skin 2 having an outer peripheral diameter b that is braided around the inner core 1. Note that the gap between the inner core 1 and the outer skin 2 is omitted in the figure, and the outer peripheral diameter b of the outer skin is also the diameter of the double rope structure 10.

[0024] When braiding the outer skin 2, the yarn fineness, number of strands, and pitch of the outer skin 2 are controlled according to the diameter, weight, specific gravity, etc. of the target inner core 1, and braiding is performed so that the suitability of the inner and outer layers falls within a predetermined range, thereby making it possible to improve the bending resistance and strength per cross-sectional area of ​​the double rope structure.

[0025] Fig. 2 is a schematic exploded side view of a double rope structure according to one embodiment of the present invention, and Fig. 3 is a schematic perspective view partially enlarged of a strand 3 forming the inner core of the double rope structure of Fig. 2. As shown in Fig. 2, the double rope structure 10 comprises an inner core 1 and an outer sheath 2 covering the inner core, the outer sheath 2 being a braided body that is integrated with the inner core 1 to form the double rope structure. In Fig. 2, the outer sheath 2 is partially omitted in order to show the state of the inner core 1.

[0026] The inner core 1 and the outer skin 2 have a structure in which a plurality of strands are twisted and / or braided, each of which is made up of a plurality of yarns, each of which is made up of a plurality of single yarns twisted together within a specific range. Each single yarn may be a monofilament or a multifilament.

[0027] For example, the strand 3 forming the inner core 1 of the double rope structure 10 in Figure 2 is composed of a plurality of yarns 4 as shown in Figure 3, and each yarn 4 is a plied body in which multiple original yarns (preferably monofilament or multifilament, particularly preferably multifilament) are twisted together.

[0028] Fig. 2 shows a cut portion 1A constituting a predetermined length V in the inner core 1. The cut portion 1A indicates the inner core portion when the double rope structure 10 is cut at the predetermined length V. When the cut portion 1A is disassembled, multiple strands constituting the cut portion 1A are obtained, and one of these strands, a strand 3A, is indicated by a dot in Fig. 2. The strand 3A is composed of multiple yarns (not shown).

[0029] 4 is a schematic perspective view for explaining the relationship between the length W of one yarn 4A of the multiple yarns forming the strand 3A of the cut portion 1A and the length V of the cut portion 1A. When the double rope structure 10 is cut at a predetermined length V, the strand 3A present in the cut portion 1A is broken down into yarns 4A, and the length of the yarns 4A is measured, and it is found that the yarns 4A have a length W.

[0030] In the double rope structure of the present invention, the length W of the yarn 4A forming the strand 3A at the cut portion 1A may be, for example, in the range of 1.005 or more and 1.400 or less, as yarn length / rope length (W / V).

[0031] Furthermore, as shown in FIG. 2, for example, the strands 3A constituting the inner core intersect with the rope longitudinal direction Z (hereinafter simply referred to as the rope longitudinal direction Z) passing through the center of the double rope structure at a crossing angle θ (0°<θ<90°) with respect to the rope longitudinal direction Z. The crossing angle θ can be measured using an image of the side of the fibers with the outer sheath 1 removed to expose the inner core 2. For example, in FIG. 2, the strands 3A intersecting with the rope longitudinal direction Z of the double rope structure 10 are selected at random, and the angle θ formed between the rope longitudinal direction Z and the edge of the strand 3A on the rope longitudinal direction Z side is taken as the crossing angle.

[0032] Figure 5 is a schematic exploded side view of a double rope structure according to another embodiment of the present invention. The double rope structure 20 includes an inner core 6 and an outer sheath 2 covering the inner core. The outer sheath 2 is a braided body, and is integrated with the inner core 6 to form the double rope structure. Note that parts common to Figure 2 are designated by the same reference numerals and will not be described again.

[0033] In this double rope structure, when the outer sheath 2 is braided, the inner core 6 and the outer sheath 2 are braided so that the inner and outer layer suitability shown in the above formula (1) falls within a predetermined range, thereby making it possible to improve the bending resistance and strength per cross-sectional area of ​​the double rope structure.

[0034] The inner core 6 has a plied structure in which a plurality of strands 7 are twisted together, and each strand is made up of a plurality of yarns, and each yarn is made up of a plurality of single yarns. For example, the strands 7 forming the inner core 6 of the double rope structure 20 in Fig. 5 are made up of a plurality of yarns 4, similar to the strands 3 shown in Fig. 3, and each yarn 4 is a plied body of a plurality of original yarns (preferably monofilament or multifilament, particularly preferably multifilament).

[0035] 5 shows a cut portion 6A constituting a predetermined length V in the inner core 6. The cut portion 6A indicates the inner core portion when the double rope structure 20 is cut at the predetermined length V. When the cut portion 6A is disassembled, multiple strands constituting the cut portion 6A are obtained, and one of these, a strand 7A, is indicated by a dot in FIG. 5. The strand 7A is composed of multiple yarns (not shown), and the length W of the yarn constituting the strand 7A relative to the length V of the cut portion 6A may be, for example, in the range of 1.005 to 1.400 in terms of yarn length / rope length (W / V).

[0036] 5, the strands 7A constituting the inner core intersect at a crossing angle θ (0°<θ<90°) with the rope longitudinal direction Z. For example, in FIG. 5, the strands 7A intersecting with the rope longitudinal direction Z passing through the center of the double rope structure 20 are selected at random, and the angle θ formed between the rope longitudinal direction Z and the side of the strands 7A on the rope longitudinal direction Z side is set as the crossing angle.

[0037] As shown in Figures 2 and 4, the outer cover 2 is formed of a braided strand. As shown in Figure 3, the strand is further composed of a plurality of yarns. Each yarn is a plied and twisted body in which a plurality of original yarns (preferably monofilament or multifilament, particularly preferably multifilament) are twisted together.

[0038] Preferred embodiments of the double rope structure are described below. (Inner core) The diameter of the inner core can be set appropriately depending on the application, but may be, for example, 0.5 to 100 mm, preferably 1.0 to 80 mm, and more preferably 1.5 to 60 mm. The diameter of the inner core is a value measured by the method described in the examples below.

[0039] In a double rope structure, the twist number of each of the multiple yarns constituting the strand of the inner core may be, for example, 150 to 0.1 T / m, preferably 100 to 2 T / m, more preferably 80 to 3 T / m, even more preferably 70 to 5 T / m, and particularly preferably 60 to 6 T / m. A small twist number can improve the strength of the rope, but an untwisted strand reduces handleability when forming the strand. Furthermore, the multiple strands constituting the inner core may be twisted as needed. For example, as a guideline for the twist number of the strands, twisting may be performed as needed within a range that satisfies the ratio of inner core yarn length to rope length. Furthermore, the multiple strands may be further twisted as needed.

[0040] The yarn fineness can be appropriately set depending on the fineness required for the double rope structure, and may be, for example, 30 to 5000 dtex, preferably 200 to 4000 dtex, more preferably 400 to 2500 dtex, and even more preferably 1000 to 2000 dtex. A yarn fineness within the above range is preferred in terms of handleability, such as strand convergence.

[0041] In the inner core constituting the double rope structure of the present invention, the yarn length / rope length (W / V), which is the ratio of the average yarn length of the yarns constituting the inner core of the cut portion to the rope length of the cut portion when cut to a length of 1 m (1.000 m to be precise), may be in the range of 1.005 to 1.400, preferably 1.005 to 1.200, more preferably 1.006 to 1.180, and even more preferably 1.007 to 1.150, from the viewpoint of improving the tensile strength of the double rope structure. The yarn length and rope length are values ​​measured by the methods described in the examples below.

[0042] The inner core of the double rope structure of the present invention may be a plied or braided body. In the case of a plied or braided body, it is often 3-strand or 4-strand, while the braided body may be 4-strand, 6-strand, 8-strand, 12-strand, 16-strand, 32-strand, 64-strand, etc. Among these, a braided body is preferred, and a 4-strand, 6-strand, 8-strand, 12-strand, 16-strand, or 32-strand braided body is particularly preferred.

[0043] When plying or braiding, the pitch (holes / inch) may be adjusted to, for example, 2.5 to 25, preferably 2.5 to 20, more preferably 3 to 18, and even more preferably 3.3 to 15. The pitch represents the number of yarns per inch in the longitudinal direction of the rope, and can be confirmed by measurement using, for example, a digital microscope VHX-2000 manufactured by Keyence Corporation.

[0044] The crossing angle θ of the strands with respect to the longitudinal direction of the rope may be, for example, 50° or less, preferably 40° or less, more preferably 35° or less, even more preferably 33° or less, still more preferably 30° or less, and particularly preferably 27° or less. The lower limit of the crossing angle may be, for example, 2° or more, preferably 3° or more, more preferably 6° or more, and even more preferably 10° or more. A crossing angle of the strands of equal to or less than the upper limit is preferred in terms of strength, and a crossing angle of equal to or greater than the lower limit is preferred in terms of bending durability.

[0045] The high-strength, high-elastic modulus fiber constituting the inner core is not particularly limited as long as it is a high-strength, high-elastic modulus fiber that can achieve a yarn strength of 20 cN / dtex or more and a yarn modulus of 400 cN / dtex or more. Specific examples include liquid crystal polyester fibers (Vectran (trademark), Scivelas (trademark), Zexion (trademark), etc.), ultra-high molecular weight polyethylene fibers (Izanas (trademark), Dyneema (trademark), etc.), aramid fibers (Kevlar (trademark), Twaron (trademark), Technora (trademark), etc.), poly(paraphenylene benzobisoxazole) fibers (Zylon (trademark), etc.), etc.

[0046] The yarn strength of the high-strength, high-elastic modulus fiber may be 20 cN / dtex or more, preferably 22 cN / dtex or more. The upper limit is not particularly limited, but may be, for example, 40 cN / dtex. The yarn modulus of the high-strength, high-elastic modulus fiber may be 400 cN / dtex or more, preferably 450 cN / dtex or more. The upper limit is not particularly limited, but may be, for example, 600 cN / dtex. Furthermore, the yarn elongation of the high-strength, high-elastic modulus fiber may be, for example, 1 to 6%, preferably 2 to 5.5%. The yarn strength, yarn modulus, and yarn elongation are values ​​measured by the methods described in the Examples below. By using such high-strength, high-elastic modulus fibers, high strength per cross-sectional area can be achieved in a double rope structure.

[0047] Of these high strength and high modulus fibers, liquid crystal polyester fibers, ultra-high molecular weight polyethylene fibers, and aramid fibers are preferred.

[0048] Liquid crystal polyester fibers can be produced, for example, by melt-spinning a liquid crystal polyester and then solid-phase polymerizing the resulting spun yarn. Liquid crystal polyester multifilaments are fibers composed of two or more liquid crystal polyester monofilaments. Liquid crystal polyesters are polyesters that exhibit optical anisotropy (liquid crystallinity) in the molten phase, and this can be confirmed, for example, by placing a sample on a hot stage, heating it under a nitrogen atmosphere, and observing the transmitted light through the sample with a polarizing microscope. Liquid crystal polyesters are composed of repeating structural units derived from, for example, aromatic diols, aromatic dicarboxylic acids, or aromatic hydroxycarboxylic acids, and the chemical structure of these structural units is not particularly limited as long as it does not impair the effects of the present invention. Furthermore, liquid crystal polyesters may also contain structural units derived from aromatic diamines, aromatic hydroxyamines, or aromatic aminocarboxylic acids, as long as it does not impair the effects of the present invention.

[0049] For example, preferred structural units include those shown in Table 1. Here, Y's may be present in a number ranging from 1 to the maximum number that can be substituted on the aromatic ring, and are each independently selected from the group consisting of a hydrogen atom, a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), an alkyl group (e.g., an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, a t-butyl group, etc.), an alkoxy group (e.g., a methoxy group, an ethoxy group, an isopropoxy group, an n-butoxy group, etc.), an aryl group (e.g., a phenyl group, a naphthyl group, etc.), an aralkyl group [e.g., a benzyl group (phenylmethyl group), a phenethyl group (phenylethyl group), etc.], an aryloxy group (e.g., a phenoxy group), an aralkyloxy group (e.g., a benzyloxy group, etc.), and the like.

[0050] More preferred structural units include the structural units described in Examples (1) to (18) shown in the following Tables 2, 3, and 4. When the structural unit in the formula is a structural unit that can exhibit multiple structures, two or more of such structural units may be combined and used as structural units that constitute the polymer.

[0051]

[0052]

[0053]

[0054] In the structural units of Tables 2, 3 and 4, n is an integer of 1 or 2, and each structural unit n=1 and n=2 may exist alone or in combination; Y １ and Y ２ may each independently represent a hydrogen atom, a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), an alkyl group (e.g., an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, a t-butyl group, etc.), an alkoxy group (e.g., a methoxy group, an ethoxy group, an isopropoxy group, an n-butoxy group, etc.), an aryl group (e.g., a phenyl group, a naphthyl group, etc.), an aralkyl group [e.g., a benzyl group (phenylmethyl group), a phenethyl group (phenylethyl group), etc.], an aryloxy group (e.g., a phenoxy group), an aralkyloxy group (e.g., a benzyloxy group, etc.), etc. Among these, preferred Y １ and Y ２ Examples of the aryl group include a hydrogen atom, a chlorine atom, a bromine atom, and a methyl group.

[0055] Examples of Z include substituents represented by the following formulas.

[0056] A preferred liquid crystal polyester preferably has two or more types of naphthalene skeletons as a structural unit. Particularly preferably, the liquid crystal polyester contains both a structural unit (A) derived from hydroxybenzoic acid and a structural unit (B) derived from hydroxynaphthoic acid. For example, the structural unit (A) can be represented by the following formula (A), and the structural unit (B) can be represented by the following formula (B). From the viewpoint of easily improving melt moldability, the ratio of the structural unit (A) to the structural unit (B) may be preferably in the range of 9 / 1 to 1 / 1, more preferably 7 / 1 to 1 / 1, and even more preferably 5 / 1 to 1 / 1.

[0057]

[0058] The total of the structural units (A) and the structural units (B) may be, for example, 65 mol % or more, more preferably 70 mol % or more, and even more preferably 80 mol % or more, based on the total structural units. Liquid crystal polyesters in which the structural units (B) account for 4 to 45 mol % of the polymer are particularly preferred.

[0059] The melting point of the liquid crystal polyester preferably used in the present invention is preferably 250 to 360°C, more preferably 260 to 320°C. Here, the melting point is the main absorption peak temperature observed when measured using a differential scanning calorimeter (DSC; Mettler "TA3000") in accordance with JIS K7121:2012. Specifically, 10 to 20 mg of sample is placed in an aluminum pan in the DSC apparatus, and nitrogen is passed through as a carrier gas at 100 cc / min. The endothermic peak is measured when the temperature is increased at 20°C / min. If a clear peak does not appear in the first run of DSC measurement due to the type of polymer, it is advisable to increase the temperature to 50°C higher than the expected flow temperature at a heating rate of 50°C / min, hold the temperature at that temperature for 3 minutes, completely melt the polymer, and then cool it to 50°C at a heating rate of -80°C / min. The endothermic peak is then measured at a heating rate of 20°C / min.

[0060] The liquid crystal polyester may contain thermoplastic polymers such as polyethylene terephthalate, modified polyethylene terephthalate, polyolefin, polycarbonate, polyamide, polyphenylene sulfide, polyether ether ketone, and fluororesin, as long as the effects of the present invention are not impaired. Furthermore, various additives may be added, such as inorganic substances such as titanium oxide, kaolin, silica, and barium oxide, colorants such as carbon black, dyes, and pigments, antioxidants, ultraviolet absorbers, and light stabilizers.

[0061] (Outer Sheath) In the double rope structure of the present invention, the outer sheath is composed of a wrapped or braided body of strands that cover the inner core. The yarns that make up the strands may be monofilament or multifilament, but multifilament is preferred. The wrapped or braided body can be formed by spirally winding the strands around the inner core, and the braided body can be formed by braiding the inner core with 8, 12, 16, 24, 32, 40, 48, 64, or other strands. Of these, braided bodies with 12, 16, 24, 32, 40, or 48 strands are preferred, and braided bodies with 12, 16, 24, 32, or 40 strands are more preferred.

[0062] The strands constituting the outer sheath may be formed from the high-strength, high-elastic modulus fibers, or may be formed from non-high-strength, non-high-elastic modulus fibers. For non-high-strength, non-high-elastic modulus fibers, for example, the yarn strength may be less than 20 cN / dtex, and typically may be about 1 cN / dtex to 15 cN / dtex. The yarn modulus may be less than 400 cN / dtex, and typically may be about 10 cN / dtex to 200 cN / dtex. The yarn elongation may be, for example, 3 to 20%, and preferably 7 to 20%.

[0063] From the viewpoint of ensuring the strength of the inner core, the non-high strength, non-high modulus fiber may be a fiber in which the ratio of the strength of the fiber used in the outer shell to the strength of the fiber used in the inner core is, for example, 0.10 to 0.40, and preferably 0.12 to 0.35.

[0064] Specific examples of non-high strength, non-high modulus fibers include general-purpose synthetic fibers, such as general-purpose polyester fibers (e.g., polyethylene terephthalate fibers), polyolefin fibers (e.g., polyethylene fibers, polypropylene fibers), polyamide fibers (e.g., nylon 6 fibers, nylon 6,6 fibers), and polyvinyl alcohol fibers (e.g., Vinylon (trademark)).

[0065] In a double rope structure, the strength of the rope structure can be ensured by the inner core, so the outer sheath may be substantially composed of non-high strength, non-high modulus fibers. Here, "substantially" means that the proportion of non-high strength, non-high modulus fibers in the outer sheath is 80% by weight or more, and preferably 90% by weight or more (90 to 100% by weight).

[0066] The fineness of the yarn forming the strand of the outer sheath can be appropriately set depending on the diameter required for the double rope structure, and may be, for example, 50 to 100,000 dtex, preferably 100 to 50,000 dtex, more preferably 200 to 40,000 dtex, even more preferably 200 to 10,000 dtex, and still more preferably 200 to 1,000 dtex. When the fineness of the yarn forming the strand of the outer sheath is within the above range, it becomes easier to adjust the suitability of the inner and outer layers.

[0067] The diameter of the double rope structure, i.e., the diameter b of the outer periphery of the outer skin, can be set appropriately depending on the application, but may be, for example, 1.0 to 250 mm, preferably 1.5 to 200 mm, and more preferably 1.8 to 100 mm. Here, the diameter b is the diameter of the outer periphery of the outer skin 2, and is the value measured by clamping the double rope structure 10 with the outer measuring jaws of an electronic vernier caliper.

[0068] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, various physical properties were measured by the following methods.

[0069] [Diameter and cross-sectional area] The diameters of the double rope structure and the inner core were measured at seven random points by clamping them with the outer measuring jaws of an electronic caliper, and then the maximum and minimum values ​​were removed to calculate the average of the five measured points. Here, the diameter of the double rope structure is used as the diameter of the outer circumference of the outer sheath. When measuring the diameter of the inner core, the outer sheath was carefully removed from the surface while keeping the inner core in a tensioned state so as not to affect the structure of the inner core of the double rope structure, and only the inner core was clamped with the outer measuring jaws of the electronic caliper and measured. The cross-sectional area of ​​the double rope structure was calculated using the diameter of the double rope structure as (diameter / 2) ２ × 3.14.

[0070] [Volume Ratio] A 1,000 m length was randomly selected from the double rope structure and cut, and its weight (weight of the double rope structure: Wi + Wo) was measured using an electronic precision balance. After the above measurement, the outer skin was carefully removed while keeping the inner core pulled, and the weight of the outer skin (outer skin weight: Wo) and the weight of the inner core (inner core weight: Wi) were measured using an electronic precision balance. Then, the volume ratio Vf (%) of the inner core to the total volume of the inner core and outer skin was calculated using the following formula: Vf = (Wi / ρi) / (Wi / ρi + Wo / ρo) × 100 where Wi is the weight (g) of the inner core, and ρi is the specific gravity (g / cm) of the inner core. ３ ), Wo is the weight of the outer skin (g), ρo is the specific gravity of the outer skin (g / cm ３ In the above formula, the specific gravities of the inner core and outer shell are determined by using the specific gravities of the polymers that make up the yarns that make up the inner core and outer shell.

[0071] [Rope length and inner core yarn length] A 1,000 m length was randomly selected and cut from a double rope structure (hereinafter sometimes simply referred to as a rope structure) to determine the rope length. The strands constituting the cut portion were disassembled to extract the inner core, and one arbitrarily selected strand constituting the inner core was further disassembled to obtain the yarn constituting the inner core. The lengths of all the obtained inner core yarns were measured in a taut state according to JIS L 1013:2021, and the average value was determined as the yarn length.

[0072] [Yarn Fineness (dtex)] The strands constituting the rope structure were disassembled to obtain the yarns constituting the inner core and outer sheath, and the yarn fineness of the obtained yarns was measured in accordance with JIS L 1013:2021.

[0073] [Yarn Tenacity (N), Yarn Strength (cN / dtex), Yarn Elongation (%), Yarn Modulus (cN / dtex)] The strands constituting the rope structure were disassembled to obtain the yarns constituting the inner core, and the tensile strength of the obtained yarns was measured as yarn strength (N), as well as the yarn elongation and yarn modulus, based on JIS L 1013: 2021. The value obtained by dividing the yarn strength (cN) by the yarn fineness (dtex) was defined as the yarn strength (cN / dtex).

[0074] [Pitch (eyes / inch)] Using a digital microscope VHX-2000 manufactured by Keyence Corporation, the number of yarns present per inch in the rope was measured and used as the pitch.

[0075] [Crossing Angle] Using a digital microscope VHX-2000 manufactured by Keyence Corporation, the angle of the strand in the inner core of the double rope structure relative to the longitudinal direction of the rope was measured.

[0076] [Tensile strength per cross-sectional area of ​​the rope (N / mm ２ ) For the double rope structure, a spiral jig for rope evaluation (manufactured by Chubu Machine Co., Ltd.) was used as a gripping jig for the universal testing machine, and the rope was wound around the groove of the spiral part, and the rope was fixed by the friction resistance of the surface, and the tensile strength of the double rope structure was measured based on JIS L 1013:2021. In addition, the diameter of the double rope structure was measured, and the cross-sectional area was calculated. The value obtained by dividing the tensile strength by the cross-sectional area was taken as the tensile strength per cross-sectional area of ​​the rope.

[0077] [Flexibility: Strength retention rate (%) after flex test] A flex test was performed using a flex testing machine (TC111L / Yuasa System) and a tension-free flex test jig (DX-TFB / Yuasa System Co., Ltd.) with a bending R of 7.5 mm and a bending angle of 240°, in which the rope was repeatedly flexed 10,000 times under a load of 1% of the tensile breaking strength, and the tensile strength of the double rope structure before and after the flex test was measured. The strength retention rate after the flex test was calculated by dividing the tensile strength of the double rope structure after the flex test by the tensile strength of the double rope structure before the flex test, and expressed as a percentage.

[0078] Example 1 An inner core rope was produced using a liquid crystal polyester multifilament (manufactured by Kuraray Co., Ltd., "Vectran," fineness 1670 dtex) as the high-strength, high-elasticity fiber on an EL-type 6-knit braiding machine (manufactured by Kokubun Co., Ltd.) by adjusting the braider rotation speed and take-up speed so that the pitch was 8.6 stitches / inch. A double rope was produced using the obtained inner core rope as the core material and a polyethylene terephthalate multifilament (manufactured by Toray Co., Ltd., fineness 280 dtex, yarn strength 7.2 cN / dtex, yarn elasticity 88 cN / dtex, yarn elongation 15.1%) on a medium-sized 32-knit braiding machine (manufactured by Kokubun Co., Ltd.) by adjusting the braider rotation speed and take-up speed so that the pitch was 50 stitches / inch.

[0079] [Example 2] A double rope structure was manufactured in the same manner as in Example 1, except that the number of strands and pitch of the inner core and the fineness and pitch of the outer sheath were changed as shown in Table 5. The results are shown in Table 5.

[0080] [Example 3] A double rope structure was produced in the same manner as in Example 1, except that the high-strength, high-elasticity fiber for the inner core of the double rope structure was changed to an ultra-high molecular weight polyethylene multifilament (manufactured by Toyobo Co., Ltd., "IZANAS", fineness 1760 dtex), the pitch of the inner core was changed to 8.5, and the pitch of the outer skin was changed to 49. The results are shown in Table 5.

[0081] [Example 4] A double rope structure was manufactured in the same manner as in Example 3, except that the number of strands and pitch of the inner core and the fineness, number of strands and pitch of the outer skin were changed as shown in Table 5. The results are shown in Table 5.

[0082] Example 5: Using a liquid crystal polyester multifilament ("Vectran," manufactured by Kuraray Co., Ltd., fineness 1670 dtex) as a high-strength, high-elasticity fiber, 38 strands were wound onto a bobbin using a winder under constant tension to produce a 38-strand bundle, which was then further wound onto a bobbin using a winder under constant tension to produce a braiding strand (fineness 2,411,480 dtex). The braiding strand was then used in a 6-strand braiding machine, with the braider speed and take-up speed adjusted to a pitch of 0.45 stitches / inch to produce an inner core rope. Twenty polyethylene terephthalate multifilaments (manufactured by Toray Industries, Inc.; fineness: 1,100 dtex; yarn strength: 6.8 cN / dtex; yarn modulus: 88 cN / dtex; yarn elongation: 14%) were used. Twenty strands were wound onto a bobbin using a winding machine under constant tension to produce a 20-strand bundle. Four strands of this bundle were then twisted 10 times / meter in the Z direction using a twisting machine under constant tension and wound onto a bobbin to produce a twisted yarn for braiding (fineness: 456,000 dtex). Using the inner core rope as the core material, a double rope structure (outer periphery diameter a of the inner core: 76 mm; outer periphery diameter b of the outer sheath: 48 mm) was produced using a 32-strand braiding machine with a pitch of 3.1 stitches / inch, adjusting the braider rotation speed and take-up speed. The inner core rope was then used as the core material.

[0083] [Comparative Example 1] A double rope structure was manufactured in the same manner as in Example 1, except that the number of strands and pitch of the inner core and the pitch of the outer skin of the double rope structure were changed as shown in Table 5. The results are shown in Table 5.

[0084] [Comparative Example 2] A double rope structure was produced in the same manner as in Example 2, except that the pitch of the inner core of the double rope structure and the fineness and number of strands of the outer skin were changed as shown in Table 5. The results are shown in Table 5.

[0085] [Comparative Example 3] A double rope structure was manufactured in the same manner as in Example 3, except that the number of strands and pitch of the inner core of the double rope structure and the fineness and pitch of the outer sheath were changed as shown in Table 5. The results are shown in Table 5.

[0086] [Comparative Example 4] A double rope structure was produced in the same manner as in Example 4, except that the pitch of the inner core of the double rope structure and the fineness and number of strands of the outer skin were changed as shown in Table 5. The results are shown in Table 5.

[0087] [Comparative Example 5] A double rope structure was produced in the same manner as in Example 1, except that the fiber for the inner core of the double rope structure was changed to polyethylene terephthalate multifilament (manufactured by Toray Industries, Inc., fineness 1670 dtex, yarn strength 8.0 cN / dtex, yarn modulus 143 cN / dtex, yarn elongation 12.6%), the pitch of the inner core was changed to 9.6, the number of ends to 12, and the pitch of the outer skin to 55. The results are shown in Table 5.

[0088]

[0089] As shown in Table 5, in all of Examples 1 to 4, the inner and outer layer suitability in the double rope structure was in the range of 0.70 to 1.20, the strength retention rate (%) after the bending test was 90% or more, and the tensile strength per cross-sectional area was 180 N / mm ２ That's all.

[0090] On the other hand, in Comparative Examples 1 and 2, the inner and outer layer suitability in the double rope structure exceeded 1.20, and the strength retention rate after the bending test was inferior to that of the Examples. Furthermore, in Comparative Examples 3 and 4, the inner and outer layer suitability in the double rope structure was below 0.70, and the tensile strength per cross-sectional area was inferior to that of the Examples. In Comparative Example 5, the fibers constituting the inner core were not high-strength or high-elasticity fibers, and therefore the strength of the entire rope structure was reduced by half compared to Example 1, which had a similar diameter.

[0091] The double rope structure of the present invention can be used very preferably in water applications such as mooring ships, edge ropes for fishing nets, mooring floating water facilities that are set up while floating on the water, marine ropes for mooring floating offshore structures used in the exploration of marine resources to the seabed, water applications such as towing lines, cargo lines, wind power generation facilities, and substation facilities, land applications such as towing lines and cargo lines, and also in fields such as sports and leisure.

[0092] As described above, a preferred embodiment of the present invention has been described with reference to the drawings. However, a person skilled in the art can read this specification and make various additions, modifications, or deletions without departing from the spirit of the present invention, and such additions, modifications, or deletions are also included within the scope of the present invention.

Claims

1. A double rope structure comprising an inner core and an outer skin, wherein the inner core is made of high-strength, high-elasticity fibers having a yarn strength of 20 cN / dtex or more and a yarn elastic modulus of 400 cN / dtex or more; A double rope structure having an inner and outer layer suitability expressed by the following formula (1) of 0.70 to 1.

20. (a ２ / b ２ ) / Vf×100 (1) In formula (1), a represents the outer diameter of the inner core, b represents the outer diameter of the outer skin, and Vf represents the volume ratio (%) of the inner core to the total volume of the inner core and the outer skin.

2. 2. The double rope structure according to claim 1, wherein a volume ratio Vf of the inner core to the total volume of the inner core and the outer skin is 10% or more.

3. 2. The double rope structure of claim 1, wherein the ratio of the average value of the yarn length of the yarn constituting the inner core of the cut portion to the rope length of the cut portion when the double rope structure is cut to a predetermined length is 1.005 or more and 1.400 or less, in terms of yarn length / rope length.

4. The double rope structure according to any one of claims 1 to 3, wherein the tensile strength of the double rope structure per cross-sectional area measured based on JIS L 1013:2021 is 180 N / mm ２ That's it, the double rope structure.

5. 4. The double rope structure according to claim 1, wherein the yarn elongation of the high strength, high modulus fiber is 1 to 6%.

6. The double rope structure according to any one of claims 1 to 3, wherein the high strength, high elastic modulus fiber is at least one selected from the group consisting of liquid crystal polyester fiber, ultra-high molecular weight polyethylene fiber, aramid fiber, and poly(paraphenylene benzobisoxazole) fiber.

7. 4. The double rope structure according to claim 1, wherein the ratio of the strength of the fibers used for the outer skin to the strength of the fibers used for the inner core is 0.10 to 0.

40.

8. 4. The double rope structure according to claim 1, wherein the outer skin is substantially composed of non-high strength, non-high modulus fibers.

9. The double rope structure according to any one of claims 1 to 3, wherein the outer sheath is made of multifilament.

10. 4. The double rope structure according to claim 1, wherein when a bending test is conducted in which bending is repeated 10,000 times at a bending R of 7.5 mm and a bending angle of 240° under a load of 1% of the tensile breaking strength of the rope, the ratio of the tensile strength of the double rope structure after the bending test to the tensile strength of the double rope structure before the bending test is 90% or more.

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