Unidirectionally stranded microbundle optical cable and manufacturing process

Abstract

A unidirectionally stranded microbundle optical cable and a manufacturing process, which relate to the technical field of optical cables. The unidirectionally stranded microbundle optical cable comprises microbundle tubes (10), a reinforcement layer (20), a water-blocking tape (30) and an outer sheath (40), wherein first water-blocking yarn (11) is provided between the microbundle tubes (10), a tear rope (31) is provided in the water-blocking tape (30), and a reinforcement member (41) is provided in the outer sheath (40); the microbundle tubes (10) are helically stranded by means of unidirectional stranding, the stranding pitch ranging from 800 mm to 900 mm; the reinforcement layer (20) is helically stranded by means of unidirectional stranding, the stranding pitch ranging from 600 mm to 800 mm; and the stranding direction of the microbundle tubes (10) is opposite to the stranding direction of the reinforcement layer (20). By means of unidirectionally stranding the microbundle tubes (10), the unidirectionally stranded microbundle optical cable can ensure a consistent stress direction of optical fibers (101), and reduce excessive consumption of excess length in the microbundle tubes (10). By means of unidirectionally stranding the reinforcement layer (20), it can be ensured that after the optical cable is stressed, the reinforcement layer (20) is stressed first, instead of the optical fibers (101).

Description

Unidirectional twisted micro-bundle optical cable and its manufacturing process

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 18, 2023, with application number 202310878616.8 and application name “Unidirectional twisted micro-bundle optical cable and manufacturing process”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of optical cables, and in particular to a unidirectional twisted micro-bundle optical cable and a manufacturing process thereof. Background Art

[0003] Micro-beam optical cables are generally used in urban backbone networks and are usually laid in outdoor pipes or overhead. Therefore, they have special requirements for the tensile performance of optical cables. The stress on the tensile components in the optical cable is very important. Therefore, the twisting method of the reinforcing components and the micro-beam tubes in the optical cable is studied. The main structure of the micro-beam optical cable includes a micro-beam tube, a reinforcing component (not only in the sheath, but also a fiber rod or other metal reinforcing component embedded in the sheath), and an outer sheath. The micro-beam tube contains at least one optical fiber, and at least one reinforcing member is embedded in the sheath; a yarn-shaped reinforcing component is between the micro-beam tube and the sheath. Usually, the water-blocking material in the micro-beam tube is filled with grease and water-blocking yarn. The grease contains at least one liquid and a thickener. The liquid is silicone oil, fluorinated oil or a mixture thereof, and the thickener is silica, bentonite, polytetrafluoroethylene or a mixture thereof; the water-blocking yarn is cotton yarn type.

[0004] The existing twisting of reinforcement elements and optical units has the following problems:

[0005] 1. The reinforcement components are unevenly stressed, and only some components are stressed during the stretching process;

[0006] 2. The micro-beam tube cannot ensure the consistent force direction after the sheath, and there is an excessive attenuation phenomenon;

[0007] 3. The excess length of the optical unit is easily consumed, resulting in the micro-beam tube being the first to be stressed;

[0008] 4. In the prior art, multiple micro-tubes and reinforcing elements are usually placed directly in a straight line, and the optical fibers in the micro-tubes are first stressed, thus failing to ensure the tensile performance of the optical cable.

[0009] In view of this, the present invention is proposed.

[0010] Summary of the Invention

[0011] One of the objectives of the present invention is to provide a unidirectional twisted microbundle optical cable to alleviate at least one of the above-mentioned problems in the prior art.

[0012] In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

[0013] A first aspect of the present invention provides a unidirectional twisted microbundle optical cable comprising a microbundle tube, a reinforcement layer, a water blocking tape, and an outer sheath;

[0014] A first water-blocking yarn is provided between the micro-bundle tubes, a tear cord is provided in the water-blocking tape, and a reinforcement member is provided in the outer sheath;

[0015] The micro-bundle tube is spirally twisted, the twisting method is unidirectional, and the twisting pitch is 800mm-900mm;

[0016] The micro-tube twisting pitch is greater than the unidirectional twisting excess length;

[0017] Calculation formula for one-way strand excess length:

[0018] Where: d-diameter of parallel reinforcement; D-outer diameter of microbeam tube; δ-wall thickness of microbeam tube; n-number of optical fiber cores in microbeam tube; d f -Outer diameter of optical fiber; h-twisting pitch; σ-tensile strength of microtube material; 0.6%-additional tensile window formed by unidirectional twisting;

[0019] The reinforcement layer is spirally twisted, the twisting method is unidirectional, and the twisting pitch is 600mm-800mm;

[0020] The twisting direction of the micro-tubes is opposite to the twisting direction of the reinforcement layers.

[0021] Furthermore, the material of the reinforcement layer is at least one of aramid, glass fiber yarn, polyester yarn and water-blocking yarn.

[0022] Furthermore, the outer sheath is made of polyolefin material.

[0023] The polyolefin material includes polyethylene material and / or low-smoke halogen-free flame-retardant polyolefin material.

[0024] Furthermore, the micro-tube includes an optical fiber, a second water-blocking yarn and a micro-tube sheath.

[0025] The number of the optical fibers is ≥1, and the optical fibers are twisted in SZ mode.

[0026] The optical fiber has a size of 250 μm in nominal diameter, 200 μm in nominal diameter, or 180 μm in nominal diameter.

[0027] Furthermore, the yarn density of the second water-blocking yarn is ≥20,000 m / kg, the tensile strength is ≥15 N, the elongation at break is ≥15%, the thermal shrinkage is ≤2.5%, the expansion rate is ≥30 ml / g / min, the expansion rate is ≥40 ml / g, and the moisture content is ≤5%.

[0028] Furthermore, the micro-bundle tube includes an optical fiber, a water-blocking fiber paste and a micro-bundle tube sheath.

[0029] The density of the water-blocking fiber paste is ≤0.88g / cm 3 , oxidation induction period ≥ 20min, dropping point ≥ 200℃, water resistance without disintegration in 7 days, water content ≤ 3%, hydrogen evolution amount ≤ 0.03μ1 / g.

[0030] Furthermore, the wall thickness of the micro-tube sheath is 0.1 mm-0.2 mm.

[0031] The micro-tube sheath is made of LSZH, TPEE or polyolefin material.

[0032] The density of the microtube sheath is 1.05 g / cm 3 -1.55g / cm 3 , tensile strength is 12MPa-18MPa, and elongation at break is 120%-550%.

[0033] A second aspect of the present invention provides a manufacturing process for the unidirectional twisted micro-bundle optical cable, comprising: first, paying out the micro-bundle tube with a payout tension of 0.8N-1.2N, and setting the angle of the optical unit into the twisting die at 20°-30°; then paying out the reinforcement layer with a payout tension of 4N-5N, and setting the angle of the reinforcement layer into the twisting die at 20°-30°; and finally, obtaining the unidirectional twisted micro-bundle optical cable through extrusion, cooling, and winding.

[0034] Furthermore, the die temperature of the extrusion is 180°C, and the temperature of other parts of the machine body is 170°C-190°C.

[0035] Furthermore, the cooling includes a first cooling and a second cooling.

[0036] The temperature of the first cooling is 40°C-50°C, and the temperature of the second cooling is 20°C-30°C.

[0037] The tension of the take-up line is 30N-50N.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] The unidirectionally twisted micro-beam optical cable provided by the present invention performs unidirectional twisting on the micro-beam tubes to ensure that the force direction of the optical fiber in the micro-beam tubes is consistent, while reducing the excessive consumption of the excess length in the micro-beam tubes. The excess length of the optical fiber in the micro-beam tubes is effectively controlled at 0.2‰-0.8‰, ensuring that there is an effective positive excess length in the tube. The reinforcement layer is also unidirectionally twisted to ensure that after the optical cable is stressed, the reinforcement layer is the first to be stressed, ensuring that the optical fiber is not stressed first. At the same time, the unidirectional twisting of the reinforcement layer can better cover the micro-beam tubes, avoiding the adhesion of the micro-beam tubes and the outer sheath and affecting attenuation. The micro-beam tubes and the reinforcement layer are both unidirectionally twisted and the twisting directions are opposite, which can ensure that the micro-beam tubes are fully covered and rounded by the reinforcement elements, thereby ensuring the roundness of the optical cable as a whole.

[0040] The manufacturing process provided by the present invention controls the pay-off tension between 0.8N and 1.2N due to the small outer diameter of the micro-beam tube and the soft material; the angle of the optical unit entering the twisting die is set to between 20° and 30° to ensure that the scraping force between the micro-beam tube and the twisting die is reduced to a minimum when entering the twisting die, thereby ensuring that the optical fiber inside the tube is not subjected to squeezing force. The pay-off tension of the reinforcement layer is between 4-5N, ensuring that the reinforcement layer can be stressed in the first place, and the reinforcement layer is evenly arranged on the reinforcement layer cage, ensuring that the reinforcement layer is evenly coated on the micro-beam tube. Controlling the angle of the reinforcement layer entering the twisting die to between 20° and 30° avoids wear between the reinforcement layer and the twisting die, reduces the strength of the reinforcement layer, and ensures that the cable core is well shaped after exiting the die without looseness. In addition, the twisting directions of the micro-beam tube cage and the reinforcement element cage should be set to opposite directions to avoid mold blockage and uneven twisting when tightening the reinforcement element twisting die. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] FIG1 is a schematic structural diagram of a unidirectional twisted microbundle optical cable provided in Example 1 of the present invention;

[0043] FIG2 is a schematic diagram of the structure of a micro-beam tube provided in Example 1 of the present invention;

[0044] FIG3 is a schematic diagram of another micro-beam tube structure provided by Example 1 of the present invention;

[0045] FIG4 is a schematic structural diagram of a unidirectional twisted microbundle optical cable provided in Example 2 of the present invention;

[0046] FIG5 is a schematic diagram of the structure of a micro-beam tube provided in Example 2 of the present invention.

[0047] Icon: 10-micro tube; 101-optical fiber; 102-second water-blocking yarn; 103-micro tube sheath; 104-water-blocking fiber paste; 11-first water-blocking yarn; 20-reinforcement layer; 30-water-blocking tape; 31-tear rope; 40-outer sheath; 41-reinforcement member. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. The components of the embodiments of the present invention can be arranged and designed in various configurations.

[0049] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0050] A first aspect of the present invention provides a unidirectional twisted microbundle optical cable comprising a microbundle tube, a reinforcement layer, a water blocking tape, and an outer sheath;

[0051] A first water-blocking yarn is arranged between the micro-bundle tubes, a tear cord is arranged in the water-blocking tape, and a reinforcement member is arranged in the outer sheath.

[0052] The water-blocking principle of the first water-blocking yarn is that the fiber body of the first water-blocking yarn can rapidly expand when it comes into contact with water to form a large gel-like substance. The gel has a very strong water-retaining capacity and can effectively prevent the growth of water, thereby preventing water from continuing to penetrate and diffuse, thereby achieving the purpose of water blocking.

[0053] Rip cord, also known as PP strapping cord or PP tear film, is typically made of polypropylene drawing-grade resin, known for its excellent plasticity, high breaking strength, and excellent tensile impact resistance. Tear film, made by stretching polypropylene blown film, offers strong tensile strength, a soft feel, and is non-toxic, odorless, and pollution-free. It also features an attractive appearance and vibrant colors. The rip cord used in unidirectional stranded micro-bundle optical cables provides resistance to pullout, absorbs heat generated by the cable during use, and prevents the cable rubber from adhering to each other.

[0054] The microtubes are spirally twisted, using a unidirectional twist method with a twist pitch of 800mm-900mm. The twist pitch of the microtubes is greater than the excess length of the unidirectional twist. This pitch ensures that the excess length within the tube is not consumed, ensuring that the tube, rather than the optical fiber, is the first to bear the force when the optical cable is subjected to stress. The unidirectional twisting ensures that the force applied to the optical fiber within the tube is consistent, thus ensuring fiber attenuation. In some embodiments of the present invention, the microtube twist pitch is typically, but not limited to, 800mm, 820mm, 840mm, 860mm, 880mm, or 900mm.

[0055] Calculation formula for one-way strand excess length:

[0056] Where: d: parallel reinforcement diameter; D: microbeam tube outer diameter; δ: microbeam tube wall thickness; n: number of optical fiber cores in the microbeam tube; d f : outer diameter of optical fiber; h: twisting pitch; σ: tensile strength of microtube material; 0.6%: additional tensile window formed by unidirectional twisting.

[0057] The reinforcement layer is helically twisted, with a unidirectional twist and a twist pitch of 600 mm to 800 mm. This twist pitch maximizes the stress on the reinforcement layer. In some embodiments of the present invention, the twist pitch of the reinforcement layer is typically, but not limited to, 600 mm, 620 mm, 640 mm, 660 mm, 680 mm, 700 mm, 720 mm, 740 mm, 760 mm, 780 mm, or 800 mm.

[0058] The twisting direction of the microtubes is opposite to that of the reinforcement layer, which avoids mold blockage and uneven twisting when tightening the reinforcement layer twisting mold. The twisting pitch of the microtubes and the twisting pitch of the reinforcement layer are uniform.

[0059] The unidirectionally twisted micro-beam optical cable provided by the present invention performs unidirectional twisting on the micro-beam tubes to ensure that the force direction of the optical fiber in the micro-beam tubes is consistent, while reducing the excessive consumption of the excess length in the micro-beam tubes. The excess length of the optical fiber in the micro-beam tubes is effectively controlled at 0.2‰-0.8‰, ensuring that there is an effective positive excess length in the tube. The reinforcement layer is also unidirectionally twisted to ensure that after the optical cable is stressed, the reinforcement layer is the first to be stressed, ensuring that the optical fiber is not stressed first. At the same time, the unidirectional twisting of the reinforcement layer can better cover the micro-beam tubes, avoiding the adhesion of the micro-beam tubes and the outer sheath and affecting attenuation. The micro-beam tubes and the reinforcement layer are both unidirectionally twisted and the twisting directions are opposite, which can ensure that the micro-beam tubes are fully covered and rounded by the reinforcement elements, thereby ensuring the roundness of the optical cable as a whole.

[0060] Furthermore, the material of the reinforcement layer is at least one of aramid, glass fiber yarn, polyester yarn and water-blocking yarn.

[0061] Furthermore, the outer sheath is made of polyolefin material.

[0062] The polyolefin material includes polyethylene material and / or low-smoke halogen-free flame-retardant polyolefin material.

[0063] Furthermore, the micro-tube includes an optical fiber, a second water-blocking yarn and a micro-tube sheath.

[0064] The number of the optical fibers is ≥1, and the optical fibers are twisted in SZ mode.

[0065] The optical fiber has a size of 250 μm in nominal diameter, 200 μm in nominal diameter, or 180 μm in nominal diameter.

[0066] The sizes of the micro beam tube include a nominal diameter of 0.9 mm, a nominal diameter of 0.95 mm, a nominal diameter of 1.1 mm or a nominal diameter of 1.35 mm.

[0067] Furthermore, the yarn density of the second water-blocking yarn is ≥20,000 m / kg, the tensile strength is ≥15 N, the elongation at break is ≥15%, the thermal shrinkage is ≤2.5%, the expansion rate is ≥30 ml / g / min, the expansion rate is ≥40 ml / g, and the moisture content is ≤5%.

[0068] Furthermore, the micro-bundle tube includes an optical fiber, a water-blocking fiber paste and a micro-bundle tube sheath.

[0069] The density of the water-blocking fiber paste is ≤0.88g / cm 3 , oxidation induction period ≥ 20min, dropping point ≥ 200℃, water resistance without disintegration in 7 days, water content ≤ 3%, hydrogen evolution amount ≤ 0.03μ1 / g.

[0070] Furthermore, the wall thickness of the micro-tube sheath is 0.1 mm-0.2 mm.

[0071] In some embodiments of the present invention, the wall thickness of the microtube sheath is typically, but not limited to, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, or 0.2 mm.

[0072] The micro-tube sheath is made of LSZH, TPEE or polyolefin material.

[0073] Low-smoke, zero-halogen (LSZH) refers to materials that are free of halogens (F, Cl, Br, I, and At) and environmentally friendly substances such as lead, cadmium, chromium, and mercury. It is a material classification for wire sheathing in the wire and cable industry. Low-smoke, zero-halogen (LSZH) wire sheathing is composed of a thermoplastic or thermoset material that emits low smoke when heated and is inherently halogen-free.

[0074] Thermoplastic polyester elastomer, or TPEE, is a linear block copolymer consisting of a polybutylene terephthalate (PBT) polyester hard segment and an aliphatic polyester or polyether soft segment. TPEE combines the excellent elasticity of rubber with the processability of thermoplastics. Its use in microtube sheaths allows for adjustable hardness and design flexibility.

[0075] In some embodiments of the present invention, the outer diameter of a 1-2 core microbeam tube is 0.9±0.05 mm, the outer diameter of a 4 core microbeam tube is 0.95±0.05 mm, the outer diameter of a 6 core microbeam tube is 1.1±0.05 mm, and the outer diameter of a 12 core microbeam tube is 1.35±0.1 mm. The inner diameter of the microbeam tube sheath is determined based on the outer diameters of the microbeam tubes.

[0076] The density of the microtube sheath is 1.05 g / cm 3 -1.55g / cm 3 , tensile strength is 12MPa-18MPa, and elongation at break is 120%-550%.

[0077] A second aspect of the present invention provides a manufacturing process for the unidirectional twisted micro-bundle optical cable, comprising: first, paying out the micro-bundle tube with a payout tension of 0.8N-1.2N, and setting the angle of the optical unit into the twisting die at 20°-30°; then paying out the reinforcement layer with a payout tension of 4N-5N, and setting the angle of the reinforcement layer into the twisting die at 20°-30°; and finally, obtaining the unidirectional twisted micro-bundle optical cable through extrusion, cooling, and winding.

[0078] The manufacturing process provided by the present invention controls the pay-off tension between 0.8N and 1.2N due to the small outer diameter of the micro-beam tube and the soft material; the angle of the optical unit entering the twisting die is set to between 20° and 30° to ensure that the scraping force between the micro-beam tube and the twisting die is reduced to a minimum when entering the twisting die, thereby ensuring that the optical fiber inside the tube is not subjected to squeezing force. The pay-off tension of the reinforcement layer is between 4-5N, ensuring that the reinforcement layer can be stressed in the first place, and the reinforcement layer is evenly arranged on the reinforcement layer cage, ensuring that the reinforcement layer is evenly coated on the micro-beam tube. Controlling the angle of the reinforcement layer entering the twisting die to between 20° and 30° avoids wear between the reinforcement layer and the twisting die, reduces the strength of the reinforcement layer, and ensures that the cable core is well shaped after exiting the die without looseness. In addition, the twisting directions of the micro-beam tube cage and the reinforcement element cage should be set to opposite directions to avoid mold blockage and uneven twisting when tightening the reinforcement element twisting die.

[0079] In some embodiments of the present invention, the unidirectional stranding mold at the stranding die of the optical unit is an outlet die 0.3 mm to 0.4 mm larger than the cable core size.

[0080] In some embodiments of the present invention, when the reinforcement layer enters the twisting die, the size of the twisting die is 0.1mm-0.2mm larger than the size of the entire cable, so as to ensure that the cable core is well shaped after exiting the die without looseness.

[0081] Furthermore, the die temperature of the extrusion is 180°C, and the temperature of other parts of the machine body is 170°C-190°C.

[0082] Furthermore, the cooling includes a first cooling and a second cooling.

[0083] The temperature of the first cooling is 40°C-50°C, and the temperature of the second cooling is 20°C-30°C.

[0084] The tension of the take-up line is 30N-50N.

[0085] Below, some embodiments of the present invention are described in detail with reference to the examples. In the absence of conflict, the following examples and features in the examples can be combined with each other. The raw materials in the examples and comparative examples, if not otherwise specified, can be purchased commercially.

[0086] Example 1

[0087] This embodiment provides a unidirectional twisted microbundle optical cable, the structure of which is shown in FIG1 , including a microbundle tube 10 , a reinforcement layer 20 , a water-blocking tape 30 , and an outer sheath 40 ;

[0088] A first water-blocking yarn 11 is provided between the micro-tubes 10 , a tear cord 31 is provided in the water-blocking tape 30 , and a reinforcement member 41 is provided in the outer sheath 40 ;

[0089] The microtube 10 is twisted in a spiral manner, and the twisting method is unidirectional. The reinforcing layer 20 is twisted in a spiral manner, and the twisting direction of the microtube 10 is opposite to that of the reinforcing layer 20.

[0090] In one implementation of this embodiment, the reinforcement layer 20 is made of at least one of aramid, glass fiber yarn, polyester yarn and water-blocking yarn.

[0091] In some implementations of this embodiment, the outer sheath 40 is made of polyolefin material, preferably polyethylene material or low-smoke halogen-free flame-retardant polyolefin material.

[0092] In some implementations of this embodiment, the microtube 10 includes an optical fiber 101, a second water-blocking yarn 102, and a microtube sheath 103, as shown in Figure 2. In some implementations of this embodiment, the optical fiber 101 is a single-mode optical fiber.

[0093] In some implementations of this embodiment, the size of the optical fiber 101 is a nominal diameter of 250 μm, a nominal diameter of 200 μm, or a nominal diameter of 180 μm.

[0094] In some implementations of this embodiment, the number of optical fibers 101 in the microtube 10 is greater than one, the optical fibers are distinguished by coloring, and the optical fibers 101 are twisted unidirectionally in the microtube 10. In some implementations of this embodiment, the number of second water-blocking yarns 102 is ≥1, and the yarn density of the second water-blocking yarn 102 is typically ≥20,000 m / kg, a tensile strength ≥15 N, an elongation at break ≥15%, a thermal shrinkage ≤2.5%, an expansion rate ≥30 ml / g / min, an expansion ratio ≥40 ml / g, and a moisture content ≤5%.

[0095] In some other implementations of this embodiment, the micro-tube 10 includes an optical fiber 101, a water-blocking paste 104 and a micro-tube sheath 103, as shown in FIG3 .

[0096] In some other implementations of this embodiment, a water-blocking fiber paste is used to replace the second water-blocking yarn 102, and the density of the water-blocking fiber paste is ≤0.88g / cm 3 , oxidation induction period ≥ 20min, dropping point ≥ 200℃, water resistance is guaranteed to be non-disintegrated for 7 days, water content ≤ 3%, hydrogen evolution amount ≤ 0.03μ1 / g.

[0097] In some implementations of this embodiment, the wall thickness of the microtube sheath 103 is 0.1 mm-0.2 mm, and the material of the microtube sheath 103 is LSZH, TPEE or other polyolefin materials, with a density of 1.05 g / cm3 to 1.55 g / cm3, a tensile strength of 12 MPa-18 MPa, and an elongation at break between 120% and 550%.

[0098] In some implementations of this embodiment, the optical fiber 101 adopts SZ twisting.

[0099] Example 2

[0100] This embodiment provides a unidirectional twisted microbundle optical cable with 144 optical fiber cores, as shown in FIG4 , including a microbundle tube 10 , a reinforcement layer 20 , a water-blocking tape 30 , and an outer sheath 40 ;

[0101] A first water-blocking yarn 11 is provided between the micro-tubes 10 , a tear cord 31 is provided in the water-blocking tape 30 , and a reinforcement member 41 is provided in the outer sheath 40 ;

[0102] The microtube 10 is twisted in a spiral manner, and the twisting method is unidirectional. The reinforcing layer 20 is twisted in a spiral manner, and the twisting direction of the microtube 10 is opposite to that of the reinforcing layer 20.

[0103] Each micro-tube 10 contains 12 optical fibers. As shown in FIG5 , the micro-tube 10 includes an optical fiber 101 , a second water-blocking yarn 102 and a micro-tube sheath 103 .

[0104] The optical fiber colors are blue, orange, green, brown, gray, white, red, black, yellow, and purple. The optical fiber adopts G.652D optical fiber. The diameter of the optical fiber coating after coloring is 245μm±15μm. The optical fiber is twisted in the micro-bundle tube 10 and is SZ twisted.

[0105] Each micro-tube 10 contains a 200D water-blocking yarn with a water-blocking yarn density of 20,000 m / kg.

[0106] The wall thickness of the micro-tube sheath 103 is 0.15 mm. The material of the micro-tube sheath is TPEE material with a density of 1.1 g / cm3, a tensile strength of 15 MPa, and an elongation at break of 320%.

[0107] The outer diameter of the 12-core microbeam tube is 1.35±0.05mm.

[0108] The micro-bundle tube 10 is twisted in a spiral unidirectional manner in the inner cavity of the sheath.

[0109] The colors of the micro beam tube 10 are blue, orange, green, brown, gray, white, red, black, yellow, purple, pink, and cyan.

[0110] The reinforcement layer 20 is made of aramid and water-blocking yarn.

[0111] Two FRP reinforcements are embedded in parallel in the outer sheath 40 , and the size of the reinforcements is 1.6±0.1 mm.

[0112] The outer sheath 40 is made of high-density polyethylene material, and the sheath wall thickness is nominally 2.6mm.

[0113] The overall outer diameter of the 144-core fully dry micro-bundle optical cable is nominally 12.0 mm.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A unidirectional twisted micro-bundle optical cable, characterized in that: It includes micro-bundle tube, reinforcement layer, water blocking tape and outer sheath; A first water-blocking yarn is arranged between the micro-bundle tubes, a tear cord is arranged in the water-blocking tape, and a reinforcing member is arranged in the outer sheath; The micro-bundle tube is spirally twisted, the twisting method is unidirectional twisting, and the twisting pitch is 800mm-900mm; The micro-tube twisting pitch is greater than the unidirectional twisting excess length; Calculation formula for excess length of one-way stranding: Where: d-diameter of parallel reinforcement; D-outer diameter of microbeam tube; δ-wall thickness of microbeam tube; n-number of optical fiber cores in microbeam tube; d f -Outer diameter of optical fiber; h-twisting pitch; σ-tensile strength of microtube material; 0.6%-additional tensile window formed by unidirectional twisting; The reinforcing layer is spirally twisted, the twisting method is unidirectional twisting, and the twisting pitch is 600mm-800mm; The twisting direction of the micro-tubes is opposite to the twisting direction of the reinforcement layers.

2. The unidirectional twisted microbundle optical cable according to claim 1, characterized in that: The reinforcing layer is made of at least one of aramid, glass fiber yarn, polyester yarn and water-blocking yarn.

3. The unidirectional twisted microbundle optical cable according to claim 1, characterized in that: The outer sheath is made of polyolefin material; The polyolefin material includes polyethylene material and / or low-smoke halogen-free flame-retardant polyolefin material.

4. The unidirectional twisted microbundle optical cable according to claim 1, characterized in that: The micro-tube comprises an optical fiber, a second water-blocking yarn and a micro-tube sheath; The number of the optical fibers is ≥ 1, and the optical fibers are SZ twisted; The size of the optical fiber includes a nominal diameter of 250 μm, a nominal diameter of 200 μm, or a nominal diameter of 180 μm.

5. The unidirectional twisted microbundle optical cable according to claim 4, characterized in that: The second water-blocking yarn has a yarn density of ≥20000 m / kg, a tensile strength of ≥15 N, an elongation at break of ≥15%, a thermal shrinkage of ≤2.5%, an expansion rate of ≥30 ml / g / min, an expansion rate of ≥40 ml / g, and a moisture content of ≤5%.

6. The unidirectional twisted microbundle optical cable according to claim 1, characterized in that: The micro-bundle tube comprises an optical fiber, a water-blocking fiber paste and a micro-bundle tube sheath; The density of the water-blocking fiber paste is ≤0.88g / cm 3 , oxidation induction period ≥ 20min, dropping point ≥ 200℃, water resistance without disintegration in 7 days, water content ≤ 3%, hydrogen evolution amount ≤ 0.03μ1 / g.

7. The unidirectional twisted microbundle optical cable according to any one of claims 4 to 6, characterized in that: The wall thickness of the microtube sheath is 0.1mm-0.2mm; The material of the micro-tube sheath is LSZH, TPEE or polyolefin material; The density of the microtube sheath is 1.05 g / cm 3 -1.55g / cm 3 , tensile strength is 12MPa-18MPa, and elongation at break is 120%-550%.

8. The manufacturing process of the unidirectional twisted microbundle optical cable according to any one of claims 1 to 7, characterized in that: First, the micro-beam tube is paid out with a pay-out tension of 0.8N-1.2N, and the angle of the optical unit entering the twisting die is set at 20°-30°; then the reinforcement layer is paid out with a pay-out tension of 4N-5N, and the angle of the reinforcement layer entering the twisting die is set at 20°-30°; finally, the unidirectional twisted micro-beam optical cable is obtained by extrusion, cooling and winding.

9. The manufacturing process according to claim 8, characterized in that: The die temperature of the extrusion is 180°C, and the temperature of other parts of the machine body is 170°C-190°C.

10. The manufacturing process according to claim 8, characterized in that: The cooling includes a first cooling and a second cooling; The first cooling temperature is 40°C-50°C, and the second cooling temperature is 20°C-30°C; The tension of the take-up line is 30N-50N.

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