Fiber reinforcement material and submarine cable comprising same

Abstract

The present invention relates to a fiber reinforcement material and a submarine cable comprising same, the fiber reinforcement material comprising, on the basis of a central layer of a specific number of straight fibers, two outer layers of stranded fibers that are a specific number of strands inserted into the vicinity thereof, and being used instead of a conventional non-metal tensile material.

Description

Fiber reinforcement and submarine cable including the same

[0001] The present invention relates to a fiber reinforcement for a submarine cable and a submarine cable including the same.

[0002] A submarine cable is a cable laid on the seabed to transmit power, communicate, and for other purposes between two points separated by the sea, such as between continents, between land and an island, or between land and the sea.

[0003] Since submarine cables are laid on the seabed, they are susceptible to damage from ship anchors or fishing gear in areas with active fishing activities, and are also damaged by natural phenomena such as sea currents, waves, sea breezes, and friction with the seabed.

[0004] Therefore, to prevent this, cables equipped with protective materials capable of shielding the interior are generally used. Submarine cables are classified into shallow-water and deep-water types depending on the laying area.

[0005] Conventional submarine cables primarily use metal tension materials such as metal wires.

[0006] However, in the case of existing metal tension cable reinforcements, there are problems with the handling, transportation, and installation of the finished product due to the weight of multiple metals.

[0007] In addition, submarine cables cannot be laid in terrain with a water depth of 1.5 km or more when using metal cable reinforcement, so they are laid by bypassing the area. Consequently, increased laying length results in higher costs.

[0008] In addition, although there are cases where the aforementioned metal tension material and non-metal tension material such as synthetic fiber are used together, there are limitations in improving the elastic modulus for various polymer exterior materials.

[0009]

[0010] The present invention is intended to provide a fiber reinforcement using a non-metallic tension material having a lower specific gravity than conventional metal tension materials, thereby facilitating handling and transportation, and a submarine cable including the same.

[0011]

[0012] The present specification provides a fiber reinforcement having an elastic modulus of 70 GPa or more, comprising: a central layer into which 3 to 5 straight fibers are inserted; 6 to 12 outer first layer stranded fibers formed around the central layer; and 12 to 20 outer second layer stranded fibers formed around the outer first layer stranded fibers.

[0013] The present specification also provides a submarine cable comprising the fiber reinforcement.

[0014]

[0015] A fiber reinforcement material according to a specific embodiment of the invention and a submarine cable including the same will be described in more detail below.

[0016] Prior to that, unless explicitly stated otherwise in this specification, technical terms are used merely to refer to specific embodiments and are not intended to limit the invention.

[0017] The singular forms used in this specification include plural forms unless the phrases clearly indicate otherwise.

[0018] As used in this specification, the meaning of 'includes' specifies certain characteristics, regions, integers, steps, actions, elements, and / or components, and does not exclude the existence or addition of other specific characteristics, regions, integers, steps, actions, elements, components, and / or groups.

[0019] As used in this specification, 'multiplied twist yarn' refers to a yarn made by twisting two or more single yarns together in one direction.

[0020] In this specification, 'straight fiber' may mean synthetic fiber yarn arranged and inserted along a central axis or central longitudinal axis for a predetermined length without twist.

[0021] In this specification, "external first layer stranded fiber" may mean a primarily formed stranded fiber that is processed into a cable or stranded in a spiral shape based on a central layer.

[0022] In this specification, "outer second layer stranded fiber" may mean a stranded fiber that is secondarily formed by spiraling or stranding the outer first layer stranded fiber with respect to the center layer.

[0023] In this specification, the term “twist” refers to a method in which the yarn in the twisted layer of a spiral stranded cable is wound spirally.

[0024] In this specification, the term “twist direction” refers to the direction of strand processing in a spirally twisted layer. To determine the twist direction of a spirally twisted layer, an observer looks at the surface of the spirally twisted layer as the cable moves away from the observer. If the strand appears to rotate clockwise as it moves away from the observer, the cable is said to have a “right twist.”

[0025] In this specification, if a strand appears to rotate counterclockwise as it moves away from an observer, it is said that the cable has a "left twist."

[0026] In this specification, the terms "center axis" and "center longitudinal axis" may be used interchangeably to denote a common longitudinal axis located radially from the center of a multilayer spiral stranded cable.

[0027] In this specification, the term "twist angle" refers to the angle formed with respect to the central longitudinal axis of a twisted stranded spiral cable.

[0028] In this specification, the term “twist length” refers to the length of a stranded cable in which a single yarn in a spirally twisted layer completes a full spiral rotation around the central longitudinal axis of the spirally twisted cable.

[0029] In this specification, "denier" indicates the thickness of a fiber and is a unit of fineness based on 1 mass (gram) per 9,000 m length of a single fiber strand. For example, 1 denier can be expressed as 1 g / 9,000 m, or 0.11 mg / m, or 0.11 tex (i.e., 1 tex = 9 denier).

[0030]

[0031] In this specification, fiber reinforcement and submarine cable may have the same meaning when including a polymer coating layer.

[0032]

[0033] The present invention will be described in detail below.

[0034] According to one embodiment of the invention, a fiber reinforcement having an elastic modulus of 70 GPa or more may be provided, comprising: a central layer into which 3 to 5 straight fibers are inserted; 6 to 12 outer first layer stranded fibers formed around the central layer; and 12 to 20 outer second layer stranded fibers formed around the outer first layer stranded fibers.

[0035] The inventors completed the present invention by confirming through experiments that the problems of conventional metal tension cable reinforcements can be solved when a plurality of non-metal tension materials (synthetic fibers) having a stranded wire structure composed of a central layer and two outer layers twisted on top of the central layer are used as fiber reinforcements.

[0036] In addition, the present invention can provide a submarine cable composed of low-density synthetic fibers by covering a thermoplastic polymer outer layer through jacketing over a plurality of synthetic fiber layers.

[0037] The fiber reinforcement of the present invention does not include a composite structure such as a metal wire in the core layer or the outer layer, but includes a core layer and a spiral two-layer outer stranded fiber surrounding it in a predetermined number and structure, thereby providing a submarine cable composed of synthetic fibers having excellent elastic modulus for various polymers. In addition, the submarine cable of the present invention is composed of non-metallic tension materials, so it can be laid even at a depth of 1.5 km or more.

[0038]

[0039] Hereinafter, the fiber reinforcement material of the present invention will be described in more detail.

[0040] The fiber reinforcement of the present invention is a composite fiber composed of a plurality of synthetic fibers.

[0041] Specifically, the fiber reinforcement comprises a central layer and two outer layers formed sequentially outside or around the central layer.

[0042] The above-mentioned central layer is a straight fiber, and the outer layer may include a specific number of two-layer stranded fibers. The outer layer may include the outer 1st layer of stranded fibers primarily formed by surrounding the central layer. The outer layer may include the outer 2nd layer of stranded fibers secondarily formed by surrounding the outer 1st layer of stranded fibers. Accordingly, the outer 1st layer of stranded fibers may refer to the primary stranded fibers in the outer layer. Additionally, the outer 2nd layer of stranded fibers may refer to the secondary stranded fibers in the outer layer. In the present invention, the central layer may form a longitudinal axis by inserting fibers in a straight line of a predetermined length using 3 to 5 threads without twisting the synthetic fiber yarn.

[0043] If the number of straight fibers in the above-mentioned central layer is less than 3, the elastic modulus due to the thermoplastic polymer coating cannot be 70 GPa or more, so the physical properties of the fiber reinforcement cannot be improved, and if it exceeds 5, mechanical properties such as tensile and flexural durability may be reduced.

[0044] In addition, the present invention includes two layers of outer stranded fibers, as shown in FIG. 1, in which a specific number of synthetic fiber yarns are sequentially inserted as stranded wires based on a central layer. FIG. 1 briefly illustrates the structure of a fiber reinforcement according to one embodiment of the invention.

[0045] In a preferred embodiment, the outer first layer twisted fibers are formed in 6 to 12 numbers by inserting yarns as twisted wires of a predetermined length onto the straight fibers of the central layer. Additionally, the outer second layer twisted fibers are formed in 12 to 20 numbers by inserting yarns as twisted wires of a predetermined length onto the outer first layer twisted fibers. However, so that the number of the outer first layer twisted fibers and the outer second layer twisted fibers does not overlap, the outer second layer twisted fibers are formed in a greater number than the outer first layer twisted fibers.

[0046] Accordingly, the fiber reinforcement may be a stranded composite cable comprising stranded fibers of an external two-layer structure with a different number based on the central layer of straight fibers shown in FIG. 1.

[0047] In addition, in the present invention, the straight fibers of the central layer, the first outer layer stranded fibers, and the second outer layer stranded fibers each comprise synthetic fibers.

[0048] Examples of the above synthetic fibers include poly(aramid) fibers, polyamides, polyesters, acrylics, or polyolefins, and specifically, may be polyaramid fibers.

[0049] In a preferred embodiment, the synthetic fiber may include an aramid yarn in which one strand has a specific fineness.

[0050] The synthetic fiber may include synthetic fiber yarns of a predetermined length and thickness. The synthetic fiber may include aramid yarns having a total average diameter of 1,000 to 27,000 denier and 0.31 to 1.70 mm.

[0051] Specifically, in the synthetic fiber, the aramid yarn may have a fineness of 1,000 denier or more, 1,400 denier or more, 2,800 denier or more, 4,200 denier or more, 5,600 denier or more, 8,000 denier or more, 9,400 denier or more, 10,800 denier or more, or 12,000 denier or more. The aramid yarn may have a fineness of 27,000 denier or less, 25,000 denier or less, 20,000 denier or less, or 17,000 denier or less. Additionally, the aramid yarn may have a fineness of 1,000 to 27,000 denier, or 1,000 to 17,500 denier.

[0052] The overall average diameter of the above aramid yarn may be 0.31 to 1.70 mm.

[0053] In one embodiment, the aramid yarn may be a plied yarn comprising 3 to 9 plies or 4 to 8 plies, or 4 to 6 plies of multifilaments using filaments of 1,420 to 2,840 denier.

[0054] In the present invention, the total input fineness of the yarn may be approximately 80,000 to 1,000,000 denier. In one embodiment, the total input fineness of the yarn may be 80,000 denier or more, 84,000 denier or more, 110,000 denier or more, 115,000 denier or more, 150,000 denier or more, 160,000 denier or more, or 170,000 denier or more. The total input fineness of the yarn may be 1,000,000 denier or less, 950,000 denier or less, 700,000 denier or less, or 64,000 denier or less.

[0055] According to a preferred embodiment, the straight fibers of the central layer, the outer 1st layer twisted fibers, and the outer 2nd layer twisted fibers may each comprise aramid yarns of 1,000 to 27,000 denier.

[0056] The yarn of the above synthetic fiber may have a length of about 15 cm to at least several meters. The straight fiber of the above core layer may have a length of several kilometers or more, or 1,000 meters or more, or several kilometers or more.

[0057] The above aramid yarn may be a plied yarn formed by twisting a nylon or polyester filament and an aramid filament downward and upward.

[0058]

[0059] Below, each component of the above fiber reinforcement is described in more detail.

[0060] The above-described central layer is characterized by forming a central axis or a central longitudinal axis by arranging 3 to 5 threads of straight fibers of a predetermined length without twisting the synthetic fiber yarn. The straight fibers forming the above-described central layer may be 3 to 5, 3 or 4, or 3.

[0061] If the above-mentioned central layer is not formed in a straight line, an improvement in the elastic modulus for various polymers cannot be expected when polymerizing the exterior material.

[0062] If the number of straight fibers in the above-mentioned core layer is less than 3 or more than 5, there is a problem in that the elastic modulus of the fiber reinforcement composite material and the thermoplastic polyester elastomer (TPEE), high-density polyethylene (HDPE), or thermoplastic polyurethane (TPU) cannot be 70 GPa or higher even with an external polymer coating.

[0063] The above-mentioned central layer may include synthetic fiber yarns of a predetermined length and thickness.

[0064] The straight fibers of the above central layer may have a length of several kilometers or more, or more than 1,000 meters or more, or more than several kilometers.

[0065] Each straight fiber included in the above-mentioned central layer may have a thickness of 1,000 to 27,000 denier.

[0066] If the denier of each straight fiber included in the above-mentioned center layer is less than 1000, the stranded layer may be unevenly stranded on the center layer. If the denier of each straight fiber included in the above-mentioned center layer exceeds 27,000, it may be difficult to control the diameter of the fiber reinforcement.

[0067] The average diameter of the center layer may be about 0.1 mm to about 15 mm. The average diameter of the center layer is at least about 0.1 mm, at least 0.5 mm, at least 1 mm, at least 2 mm, at least 3 mm, at least 4 mm, or even up to about 5 mm. In another embodiment, the average diameter of a single center wire may be less than about 0.5 mm, less than 1 mm, less than 3 mm, less than 5 mm, less than 10 mm, or less than 15 mm.

[0068] For example, the central layer may include the aramid yarn having a straight structure.

[0069] The aramid yarns of the longitudinal axis constituting the above central layer may be inserted as straight fiber structures with a length of 3 to 5 threads, which are untwisted and have a length of more than several kilometers, more than 1,000 meters, or more than several kilometers.

[0070] The above aramid yarn may have a fineness of 1,000 to 27,000 denier and an overall average diameter of 0.31 to 1.70 mm.

[0071]

[0072] In addition, the first layer of outer twisted fibers can be formed into 6 to 12 strands by inserting yarns into twisted wires of a predetermined length based on the central axis of the straight fibers of the central layer.

[0073] The above-mentioned outer first layer stranded fibers may be 6 to 12, 6 to 11, 6 to 9, or 6 to 7, and when the above specific number range is satisfied, the elastic modulus of the fiber reinforcement can be improved to a desired level.

[0074] If the number of the first layer stranded wire fibers of the above outer layer is less than 6 or more than 12, there is a problem that even if an outer polymer coating is applied, the elastic modulus of fiber reinforcement composites such as thermoplastic polyester elastomer (TPEE), high-density polyethylene (HDPE), and thermoplastic polyurethane (TPU) cannot be 70 GPa or higher.

[0075] The above fiber reinforcement may include a first layer of twisted fibers on the outside of a plurality of spiral yarns having a first twist length, which are twisted in a first twist direction around a single yarn defining a central longitudinal axis at a first twist angle defined with respect to the central longitudinal axis.

[0076] In the present invention, the relative difference between the center layer and the first twist angle may be about 4.5° or less, or 0.05 to 1.5°. The twist angle may refer to the angle of the outer first or second layer stranded fiber inserted with respect to the straight fiber of the center layer. The twist angle may be measured according to commonly known methods, for example, by measuring the twist angle of the outer layer using a digital angle measuring instrument or by calculating it through the twist angle formula of the outer layer of a cable.

[0077] Specifically, the difference in twist angle between the core layer and the outer first layer stranded fibers may be 4.5° or less, or 0.05 to 1.5°. If the difference in twist angle between the core layer and the outer first layer stranded fibers is less than 0.05°, a deviation in tensile elastic modulus may occur due to uneven length difference occurring after stranding. Additionally, if the difference in twist angle between the core layer and the outer first layer stranded fibers exceeds 4.5°, the elongation caused by twisting increases, which may result in a decrease in elasticity.

[0078] The above-mentioned outer first layer of twisted wire fibers may include a plurality of twisted wire fibers around the central layer that have the same or different twist directions.

[0079] The above-mentioned outer first layer twisted fiber may include synthetic fiber yarns of a predetermined length and thickness. The length of the above-mentioned outer first layer twisted fiber may be formed to be equal to the length of the yarn of the above-mentioned central layer.

[0080] The above-mentioned outer first layer stranded fibers may have a length of several kilometers or more, or 1,000 meters or more, or several kilometers or more. The above-mentioned central layer straight fibers may have a length of several kilometers or more, or 1,000 meters or more, or several kilometers or more.

[0081] Each stranded fiber included in the first outer stranded fiber may have a thickness of 1,000 to 27,000 denier.

[0082] If the thickness of each straight fiber included in the first outer layer of stranded wire fibers is too small, the stranded wire layer may be unevenly stranded on the center layer, and a variation in elastic modulus may occur. If the thickness of each straight fiber included in the first outer layer of stranded wire fibers is too large, the diameter of the composite material may be uneven, and the elastic modulus may decrease.

[0083] For example, the first layer of the outer stranded wire fiber may include the aramid yarn.

[0084] The aramid yarn of the first layer of the outer stranded wire fiber above may have a fineness of 1,000 to 27,000 denier and an overall average diameter of 0.31 to 1.70 mm.

[0085]

[0086] In addition, the outer second layer stranded fibers may be formed by inserting synthetic fiber yarns as stranded wires of a predetermined length onto the outer first layer stranded fibers formed with respect to a central axis, such as 12 to 20, 12 to 18, 12 to 16, or 12 to 14.

[0087] At this time, the number of the outer first layer stranded wire fibers and the outer second layer stranded wire fibers is formed so that they do not overlap. That is, when there are 12 outer first layer stranded wire fibers, the number of outer second layer stranded wire fibers is formed to be 13 or more to 20, which is more than the number of outer first layer stranded wire fibers.

[0088] Likewise, if the number of the second layer stranded wire fibers of the outer layer is less than 12 or more than 20, there is a problem in that the elastic modulus of the fiber reinforcement composite material of thermoplastic polyester elastomer (TPEE), high-density polyethylene (HDPE), and thermoplastic polyurethane (TPU) cannot be 70 GPa or higher even with an outer polymer coating.

[0089] The fiber reinforcement comprises a plurality of spiral yarns having a second twist angle defined with respect to a central longitudinal axis in a first twist direction around the outer first layer of twisted fibers and an outer first layer of twisted fibers having a second twist length.

[0090] In addition, the relative difference between the second twist angle between the central layer and the outer second layer stranded fiber may be about 4° or less, or 0.05 to 1.5°.

[0091] Specifically, the difference in twist angle between the core layer and the outer second layer stranded fiber may be 4° or less, or 0.05 to 1.5°. If the difference in twist angle between the core layer and the outer second layer stranded fiber is less than 0.05°, a deviation in tensile elastic modulus may occur due to the non-uniformity of length difference occurring after stranding. Additionally, if the difference in twist angle between the core layer and the outer second layer stranded fiber exceeds 1.5°, or if the difference in twist angle between the core layer and the outer first layer stranded fiber exceeds 4.5°, the elongation due to twisting increases, and a decrease in elasticity may occur.

[0092] The above-mentioned outer second layer stranded fiber may include a plurality of stranded fibers having the same or different twist directions around the outer first layer stranded fiber.

[0093] The outer second layer twisted wire fiber may include synthetic fiber yarns of a predetermined length and thickness. The length of the outer second layer twisted wire fiber may be formed to be equal to the length of the yarn of the central layer.

[0094] The outer second layer stranded fiber may have a length of several kilometers or more, or 1,000 meters or more, or several kilometers or more. The straight fiber of the central layer may have a length of several kilometers or more, or 1,000 meters or more, or several kilometers or more.

[0095] Each stranded fiber included in the outer second layer stranded fiber can have a thickness of 1,000 to 27,000 denier.

[0096] If the thickness of each straight fiber included in the outer second layer of twisted wire fibers is too small, the twisted wire layer on the outer first layer may be twisted unevenly. If the thickness of each straight fiber included in the outer second layer of twisted wire fibers is too large, the appearance of the composite material may be uneven. According to one example, the outer second layer of twisted wire fibers may include the aramid yarn.

[0097] The aramid yarn of the second layer of the outer stranded wire fiber above may have a fineness of 1,000 to 27,000 denier and an overall average diameter of 0.31 to 1.70 mm.

[0098]

[0099] The number of twists of the outer first layer stranded fiber and the outer second layer stranded fiber may each be 2 to 5 TPM.

[0100] If the number of twists of the outer first layer stranded fibers is too small, a deviation in tensile elastic modulus may occur due to the uneven length difference that occurs after stranding. If the number of twists of the outer first layer stranded fibers is too large, the elongation caused by twisting increases, which may result in a decrease in elasticity.

[0101] If the number of twists of the outer second layer stranded fibers is too small, a deviation in tensile elastic modulus may occur due to the uneven length difference that occurs after stranding. If the number of twists of the outer second layer stranded fibers is too large, the elongation caused by the twisting increases, and a decrease in elasticity may occur.

[0102]

[0103] The total thickness of the fiber reinforcement may have an average thickness of 3.0 to 8.0 mm. The average thickness of the fiber reinforcement can be measured and calculated according to commonly known methods, for example, by using the specific gravity and linear density of the fiber to calculate an approximate value.

[0104]

[0105] Additionally, the fiber reinforcement further comprises a thermoplastic polymer coating layer as the outermost layer. The outermost layer may be a sheath for external reinforcement. The sheath may be insulating (i.e., electrical insulating and / or thermal or acoustic insulating). In certain exemplary embodiments, the sheath provides protection for a core layer and a plurality of outer first and second layer stranded fibers. The protection may be, for example, enhanced burst resistance, enhanced corrosion resistance, enhanced ultra-high or ultra-low temperature resistance, enhanced friction resistance, etc.

[0106] In a preferred embodiment, a thermoplastic polymer coating layer may be further included on the outer two-layer stranded wire fiber.

[0107] Accordingly, the present specification may provide a composite material comprising a thermoplastic polymer and a fiber reinforcement, which can be used as a submarine cable.

[0108] The above thermoplastic polymer coating layer may include one or more selected from the group consisting of polyamide resin, polyester resin, polyolefin resin, thermoplastic polyurethane, thermoplastic polyester elastomer, thermoplastic vulcanizate, polyphenylene ether resin, and Teflon resin.

[0109] Additionally, the coating comprises a thermoplastic polymer material, more preferably a thermoplastic polymer material selected from high-density polyolefin (e.g., high-density polyethylene), medium-density polyolefin (e.g., medium-density polyethylene), and / or a thermoplastic fluoropolymer. Suitable fluoropolymers include fluorinated ethylenepropylene copolymer (FEP), polytetrafluoroethylene (PTFE), ethylenetetrafluoroethylene (ETFE), ethylenechlorotrifluoroethylene (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), and tetrafluoroethylene polymer (TFV). Particularly suitable fluoropolymers are sold under the trade names DYNEON THV FLUOROPLASTICS, DYNEON ETFE FLUOROPLASTICS, DYNEON FEP FLUOROPLASTICS, DYNEON PFA FLUOROPLASTICS, and DYNEON PVDF FLUOROPLASTICS (all available from 3M Company, St. Paul, Minnesota, USA).

[0110] The above coating may additionally include an exterior element that also functions as a strength element.

[0111] The outermost polymer layer can be formed by coating it onto the plurality of synthetic fiber layers through direct extrusion.

[0112] These fiber reinforcements can exhibit an excellent elastic modulus for thermoplastic polymers.

[0113] As a preferred example, the fiber reinforcement may have an elastic modulus of 70 GPa or more, or 75 GPa or more, or 80 GPa or more, or 81 GPa or more for the composite of the fiber reinforcement and the thermoplastic polymer after coating with a thermoplastic polymer.

[0114] The overall average diameter of the fiber reinforcement may be about 3 mm to about 8 mm.

[0115]

[0116] According to a preferred embodiment, the outer two-layer stranded fiber may include a structure formed of 6 to 12 strands in which synthetic fiber yarns are inserted as strands of a predetermined length on an outer first-layer stranded fiber formed with respect to a central axis.

[0117] The fiber reinforcement comprises a plurality of spiral yarns having a second twist angle defined with respect to a central longitudinal axis in a first twist direction around the outer first layer of twisted fibers and an outer first layer of twisted fibers having a second twist length.

[0118] In addition, the relative difference between the second twist angle between the central layer and the outer second layer stranded fiber may be about 4.5° or less, or 0.05 to 1.5°.

[0119] The above-mentioned outer second layer stranded fiber may include a plurality of stranded fibers having the same or different twist directions around the outer first layer stranded fiber.

[0120] The outer second layer twisted wire fiber may include aramid yarn of a predetermined length and thickness. The length of the outer second layer twisted wire fiber may be formed to be equal to the length of the yarn of the central layer.

[0121] The outer second layer stranded fibers may have a length of several kilometers or more, or more than 1,000 meters or more, or more than several kilometers. The straight fibers of the central layer may have a length of several kilometers or more, or more than 1,000 meters or more, or more than several kilometers.

[0122] The aramid yarn of the second layer of the outer stranded wire fiber above may have a fineness of 1,000 to 27,000 denier and an overall average diameter of 0.31 to 1.70 mm.

[0123] The aramid yarn of the second layer of the outer twisted wire fiber mentioned above may be a plied yarn including a 2-ply to 6-ply multifilament using filaments of 1,000 to 3,000 denier.

[0124] The above-mentioned external second-layer twisted wire fiber may include a plurality of external first-layer twisted wire fibers having the same or different twist directions around the external first-layer twisted wire fiber.

[0125]

[0126] Meanwhile, in the fiber reinforcement of the present invention, the outer first layer twisted fibers and the outer second layer twisted fibers may have the same or different twist directions.

[0127] Accordingly, the fiber reinforcement may include a plurality of external first-layer twisted fibers and a plurality of external second-layer twisted fibers having the same or different twist directions around a central layer.

[0128] For example, the fiber reinforcement may have a first layer structure comprising a first plurality of outer first layer stranded fibers twisted in a first twist direction around a central layer, and a second layer structure comprising a second plurality of outer second layer stranded fibers twisted in a first twist direction around the outer first layer stranded fibers.

[0129] In addition, in another embodiment, a first plurality of external first-layer stranded fibers may be stranded in a twist direction opposite to the twist direction of an adjacent radial layer [e.g., a second layer including a second plurality of external second-layer stranded fibers].

[0130] Additionally, in another embodiment, a first plurality of external first-layer stranded fibers may be stranded in the same twist direction as the twist direction of an adjacent radial layer [e.g., a second layer including a second plurality of external second-layer stranded fibers].

[0131] Furthermore, in another example, at least one of the first plurality of external first-layer stranded fibers or the second plurality of external second-layer stranded fibers may be stranded in a twist direction opposite to the twist direction of an adjacent radial layer [e.g., a second layer including the second plurality of external second-layer stranded fibers].

[0132] In addition, the fiber reinforcement has a cross-sectional shape selected from circular, elliptical, or trapezoidal in a direction substantially perpendicular to the central longitudinal axis.

[0133]

[0134] Meanwhile, according to another embodiment of the invention, a submarine cable including the fiber reinforcement of the first embodiment may be provided. The details regarding the fiber reinforcement include all the details described above in the first embodiment.

[0135] It may further include a thermoplastic polymer coating layer coated on the fiber reinforcement.

[0136] Accordingly, the above submarine cable may include a composite of a thermoplastic polymer and fiber reinforcement.

[0137] The thermoplastic polymer coating layer may have a thickness of 0.3 to 0.7 mm and may be formed on the fiber reinforcement through direct extrusion coating of a thermoplastic resin. The thermoplastic resin may be in the form of a film.

[0138] The above thermoplastic polymer coating layer may include one or more selected from the group consisting of polyamide resin, polyester resin, polyolefin resin, thermoplastic polyurethane, thermoplastic polyester elastomer, thermoplastic vulcanizate, polyphenylene ether resin, and Teflon resin.

[0139] The above submarine cable includes fiber reinforcement with a low specific gravity of the specific structure, making it easier to handle and transport than conventional metal tension materials, and can also improve the elastic modulus of the polymer regardless of the type of thermoplastic resin included in the outermost layer.

[0140] Specifically, the above submarine cable may have an elastic modulus of 70 GPa or more, or 75 GPa or more, or 80 GPa or more, or 81 GPa or more for a composite of a thermoplastic polymer and a fiber reinforcement.

[0141] In addition, another important consideration for submarine cables is the weight of the cable per unit length in seawater. However, conventional submarine cables have a problem in that they are difficult to lay in deep waters because they contain tension materials, such as metal wires, in a stranded structure outside the central axis or core layer, which increases the cable's weight.

[0142] In this regard, the present invention can solve the above problem by providing a submarine cable fiber reinforcement using multilayer synthetic fibers of a specific composition. That is, a submarine cable provided with a fiber reinforcement using the multilayer synthetic fibers can be laid in terrain with a depth of 1.5 km or more with a low specific gravity, thereby saving costs and having an economic effect.

[0143] The above submarine cable may include an electrically conductive core and a fiber reinforcement of the above embodiment.

[0144] The above electrically conductive core may be one or more electrically conductive fibers or bundles of electrically conductive fibers, or electrically conductive fibers with a multilayer structure of one or more layers.

[0145] The above submarine cable may include one or more fiber reinforcements of the above embodiment, and the fiber reinforcements of the above embodiment may be positioned in contact with the electrically conductive core and may be positioned spaced apart from it by a certain amount of space.

[0146] In the case where the electrically conductive core of the fiber reinforcement of the above embodiment is spaced apart, the distance can be appropriately adjusted according to the specific size or type, installation location, etc. of the submarine cable.

[0147] Based on the cross-section of the above submarine cable, the fiber reinforcement of the above embodiment may include 2n (where n is an integer greater than or equal to 1) with the electrically conductive core at the center,

[0148] At this time, the 2n fiber reinforcements may be formed at symmetrical positions with respect to the electrically conductive core. For example, based on the cross-section of the submarine cable, two fiber reinforcements may be located on a line dividing the electrically conductive core into two, four fiber reinforcements may be located on a line dividing the electrically conductive core into four, six fiber reinforcements may be located on a line dividing the electrically conductive core into six, or eight fiber reinforcements may be located on a line dividing the electrically conductive core into eight.

[0149] The above submarine cable can be laid to a depth of about 1,500 meters or more using the above fiber reinforcement.

[0150]

[0151] The fiber reinforcement according to the present invention comprises multilayer synthetic fibers of a specific structure with a lower specific gravity than conventional metal tensile materials, providing ease of handling and transportation, and can exhibit an excellent elastic modulus for thermoplastic polymers.

[0152] Therefore, since the submarine cable containing the fiber reinforcement can be laid in terrain with a water depth of 1.5 km or more, it can achieve cost savings compared to using conventional metal tension members.

[0153]

[0154] FIG. 1 briefly illustrates the structure of a fiber reinforcement according to one embodiment of the invention.

[0155] Figure 2 briefly illustrates the structure of the fiber reinforcement of Comparative Example 1.

[0156] Figure 3 briefly illustrates the structure of the fiber reinforcement of Comparative Example 2.

[0157] Figure 4 briefly illustrates the structure of the fiber reinforcement of Comparative Example 3.

[0158] Figure 5 briefly illustrates the structure of the fiber reinforcement of Comparative Example 4.

[0159] Figure 6 briefly illustrates the structure of the fiber reinforcement of Comparative Example 5.

[0160] Figure 7 briefly illustrates the structure of the fiber reinforcement of Comparative Example 6.

[0161] Figure 8 briefly illustrates the structure of the fiber reinforcement of Comparative Example 7.

[0162] Figure 9 briefly illustrates the structure of the fiber reinforcement of Comparative Example 8.

[0163] FIG. 10 briefly illustrates the structure of fiber reinforcements of Reference Examples 1 and 2, in which the stranding angle of the outer layer is different.

[0164]

[0165] The operation and effects of the invention will be described in more detail below through specific embodiments. However, these embodiments are merely examples of the invention and do not define the scope of the invention.

[0166]

[0167] <Examples, Comparative Examples, and Reference Examples: Preparation of Fiber Reinforcement Materials>

[0168] Example 1 (8520 denier x 21 ea)

[0169] As shown in Table 1, fiber reinforcements were manufactured by using aramid fiber yarns, each having a single synthetic fiber strand of 8,520 denier (High Modulus 1420 de'x 6-ply twisted structure), and inserting two layers of yarn to form a core layer with three straight structures and a total of 18 twisted wire structures on top of the core layer.

[0170] * Structure: 3 straight structures (center) + 6 stranded fibers (outer 1st layer stranded on the center layer) + 12 stranded fibers (outer 2nd layer stranded on the outer 1st layer)

[0171] Specifically, three strands of the above-mentioned flat yarn (no twist) were inserted in a straight line to form a center layer, and then six and twelve strands of the above-mentioned flat yarn (no twist) were sequentially inserted as strands into the outer layer of the center layer to form an outer first-layer stranded fiber and an outer second-layer stranded fiber, thereby manufacturing a multilayer aramid fiber (8,520 denier x 21 ea) which is a fiber reinforcing material (Fig. 1).

[0172] At this time, the TPM of each of the first and second layer yarns of the outer layer was set to 4 TPM, the twist angle to 0.90°, and the pitch thickness to approximately 280 nm. The twist angle of the outer layer was measured using a digital angle measuring instrument. Then, a thermoplastic resin (PA12, TPEE, HDPE) was coated onto the second stranded wire fiber through extrusion molding to form a thermoplastic resin coating layer with a thickness of 0.3 mm, thereby manufacturing a submarine cable.

[0173]

[0174] Comparative Examples 1 to 8 and Reference Examples 1 to 2

[0175] Fiber reinforcements of Comparative Examples 1 to 8 and Reference Examples 1 to 2 were prepared by changing the fineness or the composition of the core layer and outer layer, and the strand angle conditions, as shown in Table 1 below, except that they had the same thermoplastic resin coating layer as in Example 1.

[0176] The structures of Comparative Examples 1 to 8 and Reference Examples 1 and 2 are shown in FIGS. 2 to 10.

[0177]

[0178] <Experimental Example>

[0179] For the submarine cables of the above examples, comparative examples, and reference examples, the elastic modulus according to polymer coatings of PA12, thermoplastic polyester elastomer (TPEE), and high-density polyethylene (HDPE) was measured, respectively, by the following method. The results are shown in Table 2.

[0180] Method for measuring physical properties:

[0181] A 900mm sample was set to a gauge length of 500mm in a 100kN tensile testing machine and pre-loaded, and then a tensile test was performed using an Instron tensile strength and elongation testing machine.

[0182] - Pre-Loading Condition: 500N

[0183] - Speed ​​: 20mm / min

[0184]

[0185] Classification Denier Center Outer Layer Quantity (Input Basis) Total Input Denier Input Yarn Type Quantity Input Yarn Type 1st Layer 2nd Layer Twist per meter (TPM) Twist Angle Example 1 85 20 Yarn (Flat) 3 Yarns (Flat) 6 1 2 4 0.9 0 1 7 8 9 20 Comparative Example 1 No Twist 85 20 Yarn (Flat) 3 Yarns (Flat) 6 1 2 No TPM Straight Input 1 7 8 9 20 Comparative Example 2 Change in Denier and Composition 28 40 Yarn (Flat) 1 Yarn (Flat) 6 1 2 + 18 + 2 4 1 8 1.7 1 1 7 3 2 40 Comparative Example 3 Change in Denier and Composition 25 5 60 Twisted Wire (Twist) 1 Twisted Wire (Twist) 6 0 4 1.1 4 1 7 8 9 20 Comparative Example 4 Change in Denier and Composition 25 5 60 Twisted Wire (Twist) 1st Strand (Twist) 60 No TPM Straight Input 17 8 9 20 Comparative Example 5 Change in Fineness and Composition 4 5 4 40 Strand (Twist) 4th Strand (Twist) 0 0 No TPM Straight Input 18 1 7 60 Comparative Example 6 Change in Center Count 8 5 20 Yarn (Flat) 1 Yarn (Flat) 6 1 4 4 0.6 6 1 7 8 9 20 Comparative Example 7 Change in Center Count 8 5 20 Yarn (Flat) 2 Yarn (Flat) 6 1 3 4 0.8 1 7 8 9 20 Comparative Example 8 Change in Center Count 8 5 20 Yarn (Flat) 4 Yarn (Flat) 6 1 1 4 0.9 9 1 7 8 9 20 Reference Example 1 Change in Strand Angle 8 5 20 Yarn (Flat) 3 Yarn (Flat) 6 1 2 1 4 3.1 5 1 7 8 9 20 Reference Example 2 Change in Strand Angle 8 5 20 Yarn (Flat)3 yarn (Flat)612184.04178920

[0186] Classification Elasticity Modulus (GPa @ 0.4% Elongation) According to Polymer Coating PA1 2 TPEE HDPE Avg. Avg. Avg. Example 1 8 2 8 3 7 5 Comparative Example 1 No twist 80 (However, large deviation) -- Comparative Example 2 Change in fineness and composition 79 -- Comparative Example 3 Change in fineness and composition 77 -- Comparative Example 4 Change in fineness and composition 70 -- Comparative Example 5 Change in fineness and composition 70 -- Comparative Example 6 Change in number of centers 75 -- Comparative Example 7 Change in number of centers 79 -- Comparative Example 8 Change in number of centers 79 -- Reference Example 1 Change in strand angle 70 -- Reference Example 2 Change in strand angle 69 --

[0187] Through the results of Table 2 above, Example 1 showed that, compared to Comparative Examples 1 to 8 and Reference Examples 1 to 2, all composites for various thermoplastic polymer coatings exhibited an excellent elastic modulus of 70 GPa or higher.

[0188] However, Comparative Examples 1 to 8 and Reference Examples 1 to 2 had no twist of the yarn or the fineness, number of core layers, and twist angle of the outer layer were outside the scope of the present invention, so they exhibited an elastic modulus only for the polyamide resin (PA12) coating and could not show improvement in physical properties for other types of thermoplastic resins.

Claims

1. 3 to 5 straight fibers inserted into a central layer; 6 to 12 outer first-layer stranded wire fibers formed around the central layer; and It includes 12 to 20 external second-layer stranded fibers formed around the above external first-layer stranded fibers, and Fiber reinforcement having an elastic modulus of 70 GPa or more.

2. In Paragraph 1, A fiber reinforcement having a twist angle difference of 0.05 to 1.5° between the central layer and the outer first layer stranded fibers.

3. In Paragraph 1, A fiber reinforcement having a twist angle difference of 0.05 to 1.5° between the central layer and the outer second layer stranded fibers.

4. In Paragraph 1, A fiber reinforcement having a twist count of 2 to 5 TPM for each of the outer first layer stranded fibers and the outer second layer stranded fibers.

5. In Paragraph 1, The fiber reinforcement above is a fiber reinforcement having an average thickness of 3.0 to 8.0 mm.

6. In Paragraph 1, The above-mentioned outer first layer twisted fibers and outer second layer twisted fibers are fiber reinforcements having twist directions that are the same or different from each other.

7. In Paragraph 1, The straight fibers of the central layer, the first layer stranded fibers of the outer layer, and the second layer stranded fibers of the outer layer are each fiber reinforcing materials comprising synthetic fibers.

8. In Paragraph 7, The above synthetic fiber is a fiber reinforcement comprising aramid yarn having an overall average diameter of 1,000 to 27,000 denier and 0.31 to 1.70 mm.

9. In Paragraph 1, A fiber reinforcement further comprising a thermoplastic polymer coating layer on the above-mentioned outer two-layer stranded fiber.

10. In Paragraph 9, The above thermoplastic polymer coating layer is a fiber reinforcing material comprising one or more selected from the group consisting of polyamide resin, polyester resin, polyolefin resin, thermoplastic polyurethane, thermoplastic polyester elastomer, thermoplastic vulcanizate, polyphenylene ether resin, and Teflon resin.

11. Submarine cable including the fiber reinforcement of Paragraph 1 12. In claim 11, a thermoplastic polymer coating layer coated on the fiber reinforcement; Submarine cable including more 13. In claim 12, the thermoplastic polymer coating layer is a submarine cable having a thickness of 0.3 to 1.0 mm.

14. A submarine cable according to Clause 12, wherein the elastic modulus of the composite of a thermoplastic polymer and fiber reinforcement is 70 GPa or more.

15. In claim 12, the above-mentioned thermoplastic polymer coating layer comprises one or more selected from the group consisting of polyamide resin, polyester resin, polyolefin resin, thermoplastic polyurethane, thermoplastic polyester elastomer, thermoplastic vulcanizate, polyphenylene ether resin, and Teflon resin.

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