Self-reinforced polymer jacket for optical fiber cables

Abstract

Disclosed herein are methods of making an optical fiber cable, including: extruding a material including a liquid crystal polymer around an optical fiber to form an optical fiber cable including the optical fiber surrounded by a layer including the liquid crystal polymer, and then heat treating the optical fiber cable at a temperature in a range of 10 C° to 100 C° below a melting temperature of the liquid crystal polymer for a time of at least five minutes.

Description

SELF-REINFORCED POLYMER JACKET FOR OPTICAL FIBER CABLESTECHNICAL FIELD

[0001] This disclosure relates to materials technology in general and more specifically to optical fiber cables. More particularly, this disclosure describes optical fiber cables comprising an optical fiber surrounded by a layer comprising a liquid crystal polymer. The layer comprising a liquid crystal polymer confers improved tensile strength and stiffness to the optical fiber cable compared to an optical fiber without such a layer, thereby reducing or preventing the occurrence of tensile failure of the optical fiber. This disclosure also describes methods of making such optical fiber cables, including a step of extruding a material comprising a liquid crystal polymer around an optical fiber to form an optical fiber cable, followed by a step of heat treating the optical fiber cable.BACKGROUND OF THE INVENTION

[0002] Typical optical glass fibers have low tensile strength and fail at low stresses or in bending, unless they are reinforced with high strength fibers such as aramid or liquid crystal polymer (LCP). The most common commercial solution is to include one or more aramid fibers (e.g., 1500 denier) in parallel with the optical fiber during extrusion of an external polymer jacket. However, adding reinforcing fibers during extrusion of protective jackets adds significant cost and manufacturing complexity. For larger optical cables, sometimes solid thin rods, such as glass-fiber-reinforced-plastic (GFRP), are used instead of individual fibers. However, this approach becomes more difficult as cable diameter is decreased. In that case, smaller deniers of fiber are required, which increases cost and tolerance issues significantly.

[0003] Optical fiber cables having a protective layer of LCP are known. For example, US 7,570,853 describes high-strength, abrasion-resistant optical fiber cables having a supplemental layer consisting essentially of LCP to enhance the cable’s tensile strength and hermetically seal it. Similarly, US 4,778,244 describes optical fiber cables containing an extruded support member of thermotropic LCP in which the extrusion conditions are used to control the thermal expansion coefficient of the support member.

[0004] There remains a need for improvements in strengthening optical fiber cables, without suffering the above-mentioned drawbacks, such as complicated production.SUMMARY OF THE DISCLOSURE

[0005] The present inventors have recognized that a need exists to develop optical fiber cables having improved tensile strength, which are relatively simple to produce.

[0006] The following disclosure describes the preparation and utility of optical fiber cables comprising an optical fiber surrounded by a layer comprising an LCP.

[0007] Embodiments of the present disclosure, described herein such that one of ordinary skill in this art can make and use them, include methods of making an optical fiber cable, comprising: extruding a material comprising a liquid crystal polymer around an optical fiber to form an optical fiber cable comprising the optical fiber surrounded by a layer comprising the liquid crystal polymer, and then heat treating the optical fiber cable at a temperature in a range of 10 C° to 100 C° below a melting temperature of the liquid crystal polymerfor a time of at least five minutes.Additional embodiments of the present disclosure include optical fiber cables produced by such methods.

[0008] Additional objects, advantages and other features of the present disclosure will be set forth in part in the description that follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from the practice of the present disclosure. The present disclosure encompasses other and different embodiments from those specifically described below, and the details herein are capable of modifications in various respects without departing from the present disclosure. In this regard, the description herein is to be understood as illustrative in nature, and not as restrictive.DETAILED DESCRIPTION

[0009] Embodiments of this disclosure include various methods of making optical fiber cables, and the optical fiber cables produced by such methods.

[0010] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by persons of ordinary skill in the relevant art. In case of conflict, the present specification, including definitions, will control.

[0011] Unless stated otherwise, all percentages, parts, ratios, etc., are by weight.

[0012] When an amount, concentration, or other value or parameter is given as a range, or a list of upper and lower values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper and lower range limits, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the present disclosure is to be limited to the specific values recited when defining a range.

[0013] The use of “a” or “an” to describe the various elements and components herein is merely for convenience and to give a general sense of the disclosure. This description should be read to include one or at least one and the singular also includes the plural unless it is clear that it is otherwise intended.

[0014] Unless expressly stated to the contrary, “or” and “and / or” refers to an inclusive and not to an exclusive. For example, a condition “A or B”, or “A and / or B”, is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0015] The terms “about” and “approximately” as used herein refer to being nearly the same as a referenced amount or value, and should be understood to encompass ± 5% of the specified amount or value.

[0016] The term “substantially” as used herein, unless otherwise defined, means all or almost all or the vast majority, as would be understood by the person of ordinary skill in the context used. It is intended to take into account some reasonable variance from 100% that would ordinarily occur in industrial-scale or commercial-scale situations.

[0017] Throughout the present description, unless otherwise defined and described, technical terms and methods employed to determine associated measurement values are in accordance with the descriptions of ASTM D855 / D885M - 10A (2014), Standard Test Methods for Tire Cords, Tire Cord Fabrics, and Industrial Filament Yarns Made From Man-made Organic-base Fibers, published October 2014; IEC 60794-1 -21 -E1 (Optical Fiber Cables) Tensile Properties, published March 2015; and ISO 11357-3, published March 2018.

[0018] For convenience, many elements of the various embodiments disclosed herein are discussed separately. Although lists of options may be provided and numerical values may be in ranges, the present disclosure should not be considered as being limited to the separately described lists and ranges. Unless stated otherwise, each and every combination possible within the present disclosure should be considered as explicitly disclosed for all purposes.

[0019] The materials, methods, and examples herein are illustrative only and, except as specifically stated, are not intended to be limiting. Methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present disclosure.

[0020] An optical fiber for transmitting light typically comprises a core having a given index of refraction and a surrounding cladding layer having an index of refraction lower than that of the core. This makes the combination of the core and cladding capable of propagating light along the length of the optical fiber. The core and cladding typically are made of glass, such as fused silica. The core may be slightly doped with a material that increases the index of refraction relative to an undoped core.

[0021] In certain embodiments, a material comprising a liquid crystal polymer (LCP) is extruded around the optical fiber to form an optical fiber cable comprising the optical fiber surrounded by a jacket layer comprising the LCP. In some embodiments, prior to extruding the material comprising the LCP around the optical fiber, the optical fiber is a coated optical fiber comprising a glass fiber surrounded by a protective buffer coating. Polymers used in such coatings may be, for example, polyacrylates, polyimides, fluoroacrylates, silicones, carbon, polyether ether ketones (PEEK), polybutylene terephthalates (PBT), polypropylenes, polyethylenes, polyvinylchlorides, polyvinylidene fluorides, and / or polyurethanes. In such embodiments, the extrusion comprises extruding the material comprising the LCP around the coated optical fiber to form the optical fiber cable. In other embodiments, prior to extruding the material comprising the LCP around the optical fiber, the optical fiber is an uncoated optical fiber comprising a glass fiber (core + cladding) that is not coated. In some embodiments, prior to the extruding, the optical fiber (either coated or uncoated) has a diameter of at least 5 microns, at least 10 microns, at least 20 microns, at least 30 microns, at least 40 microns, at least 50 microns, at least60 microns, at least 70 microns, at least 80 microns, at least 90 microns, at least 100 microns, at least 125 microns, at least 150 microns, at least 175 microns, at least 200 microns, at least 250 microns, at least 300 microns, at least 350 microns, at least 400 microns, at least 450 microns, at least 500 microns, at least 550 microns, at least 600 microns, at least 650 microns, at least 700 microns, at least 750 microns, at least 800 microns, at least 850 microns, at least 900 microns, at least 950 microns, at least 1000 microns, at least 1050 microns, at least 1100 microns, or at least 1150 microns. In some embodiments, the diameter is at most 1200 microns, at most 1150 microns, at most 1100 microns, at most 1050 microns, at most 1000 microns, at most 950 microns, at most 900 microns, at most 850 microns, at most 800 microns, at most 750 microns, at most 700 microns, at most 650 microns, at most 600 microns, at most 550 microns, at most 500 microns, at most 450 microns, at most 400 microns, at most 350 microns, at most 300 microns, at most 250 microns, at most 200 microns, at most 175 microns, at most 150 microns, at most 125 microns, at most 100 microns, at most 90 microns, at most 80 microns, at most 70 microns, at most 60 microns, at most 50 microns, at most 40 microns, at most 30 microns, or at most 20 microns. In some embodiments, the material comprisingthe LCP is extruded around a plurality of optical fibers to form an optical fiber cable comprising the plurality of optical fibers surrounded by a jacket layer comprising the LCP. In other words, a single optical fiber cable according to the present disclosure may contain multiple optical fibers surrounded by a single jacket layer comprising the LCP. In such embodiments, the diameter of the plurality of optical fibers, prior to the extruding of LCP, is preferably within the ranges described above in this paragraph, where the diameter of the plurality of optical fibers is an effective diameter of the collection of optical fibers, rather than a diameter of an individual optical fiber.

[0022] In some embodiments, a reinforcing fiber may be added to the optical fiber or plurality of fibers during the extruding. Such a reinforcing fiber may be an aramid fiber or an LCP fiber. The reinforcing fiber is included in parallel with the optical fiber(s) during extrusion of the material comprising the LCP. If the reinforcing fiber is an LCP fiber, then this LCP may be the same as or different from the LCP used in the extrusion material. In some embodiments, a reinforcing fiber is not preferred. In these embodiments, a reinforcing fiber is not added to the optical fiber(s) during the extruding of the material comprising the LCP. That is, a reinforcing fiber is not added in parallel with the optical fiber(s) during the extruding of the material comprising the LCP. In this situation, the extruded LCP material, rather than a reinforcing fiber, enhances the tensile strength of the optical fiber(s).

[0023] Techniques for extruding LCP, and materials comprising LCP, around optical fibers are known to those of ordinary skill in the art. See, for example US 7,570,853, incorporated herein by reference.

[0024] In some embodiments, after the material comprising LCP has been extruded around an optical fiber or plurality of fibers to form an optical fiber cable (comprising the optical fiber(s) surrounded by a layer comprising the LCP), the optical fiber cable can be heat treated. In some embodiments, the heat treatment may be performed at a temperature in a range of 10 C° to 100 C° below a melting temperature of the LCP. For example, if the LCP has a melting temperature of 280 °C, then a temperature 10 C° to 100 C° below this melting temperature is 180 °C to 270 °C. This temperature rangepreferably is 10 C° to 25 C° below the melting temperature of the LCP, more preferably 15 C° to 25 C° below the melting temperature, even more preferably 15 C° to 20 C° below the melting temperature. The melting temperature of the LCP may be determined according to ISO 11357-3.

[0025] In some embodiments, the heat treatment is performed at a temperature of at least 180 °C, at least 185 °C, at least 190 °C, at least 195 °C, at least 200 °C, at least 205 °C, at least 210 °C, at least 215 °C, at least 220 °C, at least 225 °C, at least 230 °C, at least 235 °C, at least 240 °C, at least 245 °C, at least 250 °C, at least 255 °C, at least 260 °C, at least 265 °C, at least 270 °C, at least 275 °C, at least 280 °C, or at least 300 °C. In some embodiments, the heat treatment is performed at a temperature of at most 320 °C, at most 300 °C, at most 280 °C, at most 275 °C, at most 270 °C, at most 265 °C, at most 260 °C, at most 255 °C, at most 250 °C, at most 245 °C, at most 240 °C, at most 235 °C, at most 230 °C, at most 225 °C, at most 220 °C, at most 215 °C, at most 210 °C, at most 205 °C, at most 200 °C, at most 195 °C, at most 190 °C, or at most 185 °C.

[0026] The heat treatment may be performed for a time of at least five minutes, such as at least 10 minutes, at least 15 minutes, at least 20 minutes, at least 25 minutes, at least 30 minutes, at least 35 minutes, at least 40 minutes, at least 45 minutes, at least 50 minutes, at least 55 minutes, at least 60 minutes, at least 70 minutes, at least 80 minutes, at least 90 minutes, at least 100 minutes, at least 110 minutes, at least 120 minutes, at least 3 hours, at least 4 hours, at least 5 hours, at least 6 hours, at least 8 hours, at least 10 hours, at least 12 hours, at least 14 hours, at least 16 hours, at least 18 hours, at least 20 hours, or at least 22 hours. The heat treating preferably is performed for a time of at most 24 hours, at most 22 hours, at most 20 hours, at most 18 hours, at most 16 hours, at most 14 hours, at most 12 hours, at most 10 hours, at most 8 hours, at most 6 hours, at most 5 hours, at most 4 hours, at most 3 hours, at most 120 minutes, at most 110 minutes, at most 100 minutes, at most 90 minutes, at most 80 minutes, at most 70 minutes, at most 60 minutes, at most 55 minutes, at most 50 minutes, at most 45 minutes, at most 40 minutes, at most 35 minutes, at most 30 minutes, at most 25 minutes, at most 20 minutes, at most 15 minutes, or at most 10 minutes.

[0027] In some embodiments, the heat treatment is performed in a continuous manner, whereby the optical fiber cable is heat treated during its continuous production. In such embodiments, the time of the heat treatment is a residence time of the optical fiber cable as it is continuously produced and moves continuously through such heat treatment conditions, such as an in-line or roll-to-roll manner. In other embodiments, the heat treatment is performed in a batch manner. For example, a bobbin of the optical fiber cable may be heat treated at a temperature for a time specified above, such as an on- spool manner.

[0028] In some embodiments, the heat treatment is performed in a series of different stages, with the same or different temperature and / or time for each stage. The temperatures and times can be as disclosed above. For example, the heat treatment could include a first stage at 180 °C for one hour, followed by a second stage at 200 °C for one hour, followed by a third stage at 220 °C for two hours. More broadly, the heat treatment could include a first stage at a temperature in a range of 180 °C to 190 °C for a time in a range of 50 minutes to 70 minutes, followed by a second stage at a temperature in a range of 190 °C to 210 °C for a time in a range of 50 minutes to 70 minutes, followed by a third stage at a temperature in a range of 210 °C to 230 °C for a time in a range of 110 minutes to 120 minutes. The number of stages in such embodiments is not particularly limited, and can be, e.g., at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, or at least 9; and, e.g., at most 10, at most 9, at most 8, at most 7, at most 6, at most 5, at most 4, at most 3, or at most 2.

[0029] In some embodiments, the heat treatment is performed with a varying temperature, either during the entirety of the heat treatment, during one or more stages of a multi-stage heat treatment, or between different stages of a multi-stage heat treatment. In such embodiments, the temperature can vary continuously, such as gradually ramping up or down. Ramp rates for the temperature (up or down) can be, for example, at least 0.1 C° / minute, at least 0.2 C° / minute, at least 0.3 C7minute, at least 0.4 C7minute, at least 0.5 C7minute, at least 0.6 C7minute, at least 0.7 C7minute, at least 0.8 C7minute, at least 0.9 C7minute, at least 1 .0 C7minute, at least 2.0 C7minute,at least 3.0 C7minute, at least 4.0 C7minute, at least 5.0 C7minute, at least 6.0 C7minute, at least 7.0 C7minute, at least 8.0 C7minute, at least 9.0 C7minute, or at least 10 C7minute. Ramp rates for the temperature (up or down) can be, for example, at most 20 C7minute, at most 18 C7minute, at most 16 C7minute, at most 14 C7minute, at most 12 C7minute, at most 10 C7minute, at most 9.0 C7minute, at most 8.0 C7minute, at most 7.0 C7minute, at most 6.0 C7minute, at most 5.0 C7minute, at most 4.0 C7minute, at most 3.0 C7minute, at most 2.0 C7minute, or at most 1 .0 C7minute.

[0030] In some embodiments, the heat treating is performed in an atmosphere of air. In other embodiments, the heat treating is performed in an atmosphere containing a reduced concentration of oxygen relative to air. For example, such an atmosphere may contain less than 20 mass% oxygen, less than 15 mass% oxygen, less than 10 mass% oxygen, less than 5.0 mass% oxygen, less than 4.0 mass% oxygen, less than 3.0 mass% oxygen, less than 2.0 mass% oxygen, less than 1 .0 mass% oxygen, less than 1000 ppm oxygen, less than 100 ppm oxygen, less than 60 ppm oxygen, less than 50 ppm oxygen, less than 40 ppm oxygen, less than 30 ppm oxygen, less than 20 ppm oxygen, or less than 10 ppm oxygen. Such an atmosphere containing a reduced concentration of oxygen relative to air may be termed an inert or non-oxidizing atmosphere, and may comprise or consist of inert gases such as nitrogen or argon.

[0029] In some embodiments, after the heat treating, the optical fiber cable has a diameter of at least 25 microns, at least 30 microns, at least 40 microns, at least 50 microns, at least 60 microns, at least 70 microns, at least 80 microns, at least 90 microns, at least 100 microns, at least 120 microns, at least 150 microns, at least 175 microns, at least 200 microns, at least 250 microns, at least 300 microns, at least 350 microns, at least 400 microns, at least 450 microns, at least 500 microns, at least 600 microns, at least 700 microns, at least 800 microns, at least 900 microns, at least 1000 microns, at least 1500 microns, at least 2000 microns, at least 2500 microns, at least 3000 microns, at least 3500 microns, at least 4000 microns, or at least 4500 microns. In some embodiments, the diameter is at most 5000 microns, at most 4500 microns, at most 4000 microns, at most 3500 microns, at most 3000 microns, at most 2500 microns, at most2000 microns, at most 1500 microns, at most 1000 microns, at most 900 microns, at most 800 microns, at most 700 microns, at most 600 microns, at most 500 microns, at most450 microns, at most 400 microns, at most 350 microns, at most 300 microns, at most250 microns, at most 200 microns, at most 175 microns, at most 150 microns, at most120 microns, at most 100 microns, at most 90 microns, at most 80 microns, at most 70 microns, or at most 60 microns.

[0030] In some embodiments, after the heat treating, the layer comprising the LCP has a thickness of at least 10 microns, at least 20 microns, at least 30 microns, at least 40 microns, at least 50 microns, at least 75 microns, at least 100 microns, at least 125 microns, at least 150 microns, at least 200 microns, at least 250 microns, at least 300 microns, at least 400 microns, at least 500 microns, at least 600 microns, at least 700 microns, at least 800 microns, at least 900 microns, at least 1000 microns, at least 1500 microns, or at least 2000 microns. In some embodiments, after the heat treating the thickness is at most 2500 microns, at most 2000 microns, at most 1500 microns, at most 1000 microns, at most 900 microns, at most 800 microns, at most 700 microns, at most 600 microns, at most 500 microns, at most 400 microns, at most 300 microns, at most 250 microns, at most 200 microns, at most 150 microns, at most 125 microns, at most 100 microns, at most 75 microns, at most 50 microns, at most 40 microns, at most 30 microns, or at most 20 microns.

[0031] In some embodiments, after the heat treating, the optical fiber cable has a break load of at least 50 N, at least 100 N, at least 500 N, at least 1000 N, at least 2000 N, at least 3000 N, or at least 4000 N. In some embodiments, the break load after the heat treating is at most 5000 N, at most 4000 N, at most 3000 N, at most 2000 N, at most 1000 N, at most 500 N, or at most 100 N. In some embodiments, the break load of the optical fiber cable is greater by at least a certain percentage after the heat treating compared to before the heat treating. For example, the break load of the optical fiber cable after heat treating may be greater by at least 25%, at least 50%, at least 100%, at least 200%, or at least 300% than the break load of the optical fiber cable before heat treating. In this context, a break load that is “greater by at least 25%” after the heat treatingcompared to before the heat treating means that if the break load of the optical fiber cable before the heat treating were 100 N, then the break load of the optical fiber cable after the heat treating would be at least 125 N.

[0032] The LCP in the extruded material may include a thermotropic LCP, a lyotropic LCP, or a mixture of both. The LCP may include two or more kinds of the same type of LCP, for example two or more kinds of thermotropic LCP or two or more kinds of lyotropic LCP. Lyotropic polymers decompose before melting but form liquid crystals in solution under appropriate conditions (these polymers typically are solution spun). Lyotropic polymers include, for example, aramids and poly(p-phenylene benzobisoxazole) (PBO), as well as copolymer aramids. Thermotropic polymers exhibit liquid crystal formation in the melt state. Thermotropic polymers include, for example, an aromatic polyester formed by the polycondensation of 4-hydroxybenzoic acid and 6-hydroxynaphthalene-2- carboxylic acid, commercially available under the tradename LaperosO from Polyplastics.

[0033] In some embodiments, the material comprising the LCP can further comprise one or more non-LCP components. Such non-LCP components may include, but are not limited to, polyether ether ketone, ultra-high molecular weight polyethylene, high modulus polyethylene (HMPE), polypropylene, polyethylene terephthalate, polyamide, polyvinyl alcohol, polyhydroquinone diimidazopyridine (PIPD), and combinations thereof, just to name a few. In some embodiments, a single kind of non-LCP component can be used. In other embodiments, two or more kinds of non-LCP components can be used. In yet other embodiments, a specific kind of non-LCP component may be excluded from the material comprising the LCP. For example, the material comprising the LCP may comprise no HMPE. The amount of LCP in the material comprising LCP preferably is at least 10 mass% (based on 100 mass% of the material comprising LCP), at least 15 mass%, at least 20 mass%, at least 25 mass%, at least 30 mass%, at least 35 mass%, at least 40 mass%, at least 45 mass%, at least 50 mass%, at least 55 mass%, at least 60 mass%, at least 65 mass%, at least 70 mass%, at least 75 mass%, at least 80 mass%, at least 85 mass%, at least 90 mass%, at least 95 mass%, at least 96 mass%, at least 97 mass%, at least 98 mass%, at least 99 mass%, or even 100 mass%. The amount of LCP in thematerial comprising LCP may be less than 100 mass%, for example it may be at most 99 mass %, at most 98 mass%, at most 97 mass%, at most 96 mass%, at most 95 mass%, at most 90 mass%, at most 85 mass%, at most 80 mass%, at most 75 mass%, at most 70 mass%, at most 65 mass%, at most 60 mass%, at most 55 mass%, at most 50 mass%, at most 45 mass%, at most 40 mass%, at most 35 mass%, at most 30 mass%, at most 25 mass%, or at most 20 mass%.

[0034] In some embodiments, the optical fiber or plurality of fibers may further include a second layer on the first layer of heat treatable LCP. Such a second layer may comprise the same or different LCP as present in the material of the first layer comprising the LCP, and / or one or more other materials such as polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polytetrafluoroethylene (PTFE), or another protective thermoplastic polymer. Such a second layer may be co-extruded with the first layer of heat treatable LCP during extrusion of the material comprising the LCP, or such a second layer may be applied after the material comprising the LCP already has been extruded.

[0037] In some embodiments, the optical fiber or plurality of fibers may include a layer comprising the heat treatable LCP in combination with (i) a different LCP and / or (ii) one or more other materials such as polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polytetrafluoroethylene (PTFE), or another protective thermoplastic polymer. Such a layer may be produced by so-called islands-in-the-sea extrusion, where one or more of the components exist as islands in a sea of one or more of the other components. For example, the heat treatable LCP can be present as one or more islands coextruded in a sea of a different LCP, PEN, PEEK, PTFE, or other protective thermoplastic polymer.

[0035] Polymerized units of the LCP and non-LCP may include those shown in Table 1.Table 1(in which X in the formulas is selected from the following structures)(in which m = 0 to 2, and Y = a substituent selected from a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, and an aralkyloxy group)

[0036] Regarding the polymerized units illustrated in Table 1 above, the number of Y substituent groups is equal to the maximum number of substitutable positions in the ring structure, and each Y independently represents a hydrogen atom, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, or a t-butyl group), an alkoxy group (for example, a methoxy group, an ethoxy group, an isopropoxy group, an n-butoxy group, etc.), an aryl group (for example, a phenyl group, a naphthyl group, etc.), an aralkyl group [a benzyl group (a phenylmethyl group), a phenethyl group (a phenylethyl group), etc.], an aryloxy group (for example, a phenoxy group, etc.), an aralkyloxy group (for example, a benzyloxy group, etc.), or mixtures thereof.

[0037] The LCP may be composed of a repeating polymerized unit, for example, derived from an aromatic diol, an aromatic dicarboxylic acid, or an aromatic hydroxycarboxylic acid. The LCP may optionally further comprise a polymerized unitderived from an aromatic diamine, an aromatic hydroxyamine, and / or an aromatic aminocarboxylic acid.

[0038] More specific polymerized units are illustrated in the following structures shown in Tables 2 to 4 below.

[0039] When the polymerized unit in the formulas is a unit which can represent plural structures, two or more units may be used in combination as polymerized units constituting a polymer.

[0040] In the polymerized units of Tables 2, 3, and 4, n is an integer of 1 or 2, and the respective units n = 1 , n = 2 may exist alone or in combination; and Yi and Y2 each independently may be a hydrogen atom, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, or a t-butyl group), an alkoxy group (for example, a methoxy group, an ethoxy group, an isopropoxy group, an n-butoxy group, etc.), an aryl group (for example, a phenyl group, a naphthyl group, etc.), an aralkyl group (a benzyl group (a phenylmethyl group), a phenethyl group (a phenylethyl group), etc.), an aryloxy group (for example, a phenoxy group, etc.), an aralkyloxy group (for example, a benzyloxy group, etc.), or mixtures thereof. Among these groups, Y is preferably a hydrogen atom, a chlorine atom, a bromine atom, or a methyl group.Table 2Table 3Table 4

[0041] Z in (14) of Table 3 may comprise divalent groups represented by the formulae below:

[0042] In some embodiments an LCP may be a combination comprising a naphthalene skeleton as a polymerized unit. Particularly, it may include both a polymerized unit (A) derived from 4-hydroxybenzoic acid and a polymerized unit (B) derived from 6- hydroxynaphthalene-2-carboxylic acid. For example, the unit (A) may be of formula (A)and the unit (B) may be of formula (B). From the viewpoint of improving melt moldability, a ratio of the units (A) to the units (B) may be in a range of from 9 / 1 to 1 / 1 , preferably 7 / 1 to 1 / 1 , and more preferably 5 / 1 to 1 / 1.

[0043] The total of the polymerized units (A) and the polymerized units (B) may be, for example, about 65 mol% or more, or about 70 mol% or more, or about 80 mol% or more, based on the total polymerized units. In some embodiments the filaments may include a liquid crystalline polyester comprising about 4 to about 45 mol% of the polymerized unit (B) in the polymer.

[0044] Commercially available LCP polymers of the present disclosure may include for example Vectra® and Zenite ® manufactured by Celanese, Laperos® manufactured by Polyplastics, Sumikasuper® manufactured by Sumitomo, and Xydar® manufactured by Solvay.

[0045] Commercially available non-LCP high temperature thermoplastic polymers include polyether ether ketone (PEEK) materials such as VICTREX™ PEEK polymers, polytetrafluoroethylene (PTFE) such as Teflon™, and polyethylene naphthalate (PEN).EMBODIMENTS

[0046] Embodiment [1] of the present disclosure relates to a method of making an optical fiber cable, comprising: extruding a material comprising a liquid crystal polymer around an optical fiber to form an optical fiber cable comprising the optical fiber surrounded by a layer comprising the liquid crystal polymer, and thenheat treating the optical fiber cable at a temperature in a range of 10 C° to 100 C° below a melting temperature of the liquid crystal polymer for a time of at least five minutes.

[0047] Embodiment [2] of the present disclosure relates to the method of Embodiment [1], wherein the liquid crystal polymer comprises a thermotropic liquid crystal polymer.

[0048] Embodiment [3] of the present disclosure relates to the method of Embodiment [1] or [2], wherein the heat treating is performed for a time of five minutes to 8 hours.

[0049] Embodiment [4] of the present disclosure relates to the method of at least one of Embodiments

[0001] -[3], wherein a reinforcing fiber is added in parallel with or in a helical wrap around the optical fiber during the extruding.

[0050] Embodiment [5] of the present disclosure relates to the method of at least one of Embodiments

[0001] -[3], wherein a reinforcing fiber is not added in parallel with the optical fiber during the extruding.

[0051] Embodiment [6] of the present disclosure relates to the method of at least one of Embodiments

[0001] -[5], further comprising co-extruding, in a second layer on the material comprising the liquid crystal polymer, or as a sea in which the material comprising the liquid crystal polymer exists as one or more islands, at least one material selected from the group consisting of polyethylene naphthalate (PEN), polyether ether ketone (PEEK), and polytetrafluoroethylene (PTFE).

[0052] Embodiment [7] of the present disclosure relates to the method of at least one of Embodiments

[0001] -[6], wherein, prior to the extruding, the optical fiber is a coated optical fiber comprising a glass fiber surrounded by a coating, and the extruding comprisesextruding the material comprising the liquid crystal polymer around the coated optical fiber.

[0053] Embodiment [8] of the present disclosure relates to the method of Embodiment [7], wherein the coating is an acrylate coating.

[0054] Embodiment [9] of the present disclosure relates to the method of at least one of Embodiments

[0001] -[6], wherein, prior to the extruding, the optical fiber is an uncoated optical fiber comprising a glass fiber that is not coated.

[0055] Embodiment

[0010] of the present disclosure relates to the method of at least one of Embodiments

[0001] -[9], wherein, prior to the extruding, the optical fiber has a diameter of 5 microns to 1000 microns.

[0056] Embodiment

[0011] of the present disclosure relates to the method of at least one of Embodiments

[0001] -

[0010] , wherein, after the heat treating, the optical fiber cable has a diameter of 25 microns to 2500 microns.

[0057] Embodiment

[0012] of the present disclosure relates to the method of at least one of Embodiments

[0001] -

[0011] , wherein, after the heat treating, the layer comprising the liquid crystal polymer has a thickness of 10 microns to 1000 microns.

[0058] Embodiment

[0013] of the present disclosure relates to the method of at least one of Embodiments

[0001] -

[0012] , wherein, after the heat treating, the optical fiber cable has a break load of at least 100 N.

[0059] Embodiment

[0014] of the present disclosure relates to the method of at least one of Embodiments

[0001] -

[0013] , wherein the heat treating is performed in an atmosphere containing a reduced concentration of oxygen relative to air.

[0063] Embodiment

[0015] of the present disclosure relates to a method of making an optical fiber cable, comprising: extruding a material comprising a liquid crystal polymer around a plurality of optical fibers to form an optical fiber cable comprising the plurality of optical fibers surrounded by a layer comprising the liquid crystal polymer, and then heat treating the optical fiber cable at a temperature in a range of 10 C° to 100 C° below a melting temperature of the liquid crystal polymer for a time of at least five minutes.

[0060] Embodiment

[0016] of the present disclosure relates to the method of Embodiment

[0015] , wherein the liquid crystal polymer comprises a thermotropic liquid crystal polymer.

[0061] Embodiment

[0017] of the present disclosure relates to the method of Embodiment

[0015] or

[0016] , wherein the heat treating is performed for a time of five minutes to 8 hours.

[0062] Embodiment

[0018] of the present disclosure relates to the method of at least one of Embodiments

[0015] -

[0017] , wherein a reinforcing fiber is added in parallel with or in a helical wrap around the plurality of optical fibers during the extruding.

[0063] Embodiment

[0019] of the present disclosure relates to the method of at least one of Embodiments

[0015] -

[0017] , wherein a reinforcing fiber is not added in parallel with the plurality of optical fibers during the extruding.

[0064] Embodiment

[0020] of the present disclosure relates to the method of at least one of Embodiments

[0015] -

[0019] , further comprising co-extruding, in a second layer on the material comprising the liquid crystal polymer, or as a sea in which the material comprising the liquid crystal polymer exists as one or more islands, at least one material selected from the group consisting of polyethylene naphthalate (PEN), polyether ether ketone (PEEK), and polytetrafluoroethylene (PTFE).

[0065] Embodiment

[0021] of the present disclosure relates to the method of at least one of Embodiments

[0015] -

[0020] , wherein, prior to the extruding, the plurality of optical fibers is a plurality of coated optical fibers each comprising a glass fiber surrounded by a coating, and the extruding comprises extruding the material comprising the liquid crystal polymer around the plurality of coated optical fibers.

[0066] Embodiment

[0022] of the present disclosure relates to the method of Embodiment

[0021] , wherein the coating is an acrylate coating.

[0067] Embodiment

[0023] of the present disclosure relates to the method of at least one of Embodiments

[0015] -

[0020] , wherein, prior to the extruding, the plurality of optical fibers is a plurality of uncoated optical fibers each of which is a glass fiber that is not coated.

[0068] Embodiment

[0024] of the present disclosure relates to the method of at least one of Embodiments

[0015] -

[0023] , wherein, prior to the extruding, the plurality of optical fibers has a diameter of 5 microns to 1000 microns.

[0069] Embodiment

[0025] of the present disclosure relates to the method of at least one of Embodiments

[0015] -

[0024] , wherein, after the heat treating, the optical fiber cable has a diameter of 25 microns to 2500 microns.

[0070] Embodiment

[0026] of the present disclosure relates to the method of at least one of Embodiments

[0015] -

[0025] , wherein, after the heat treating, the layer comprising the liquid crystal polymer has a thickness of 10 microns to 1000 microns.

[0071] Embodiment

[0027] of the present disclosure relates to the method of at least one of Embodiments

[0015] -

[0026] , wherein, after the heat treating, the optical fiber cable has a break load of at least 100 N.

[0076] Embodiment

[0028] of the present disclosure relates to the method of at least one of Embodiments

[0015] -

[0027] , wherein the heat treating is performed in an atmosphere containing a reduced concentration of oxygen relative to air.

[0072] The above description is presented to enable a person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the embodiments disclosed herein will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, this invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. In this regard, certain embodiments within the disclosure may not show every benefit of the invention, considered broadly.

Claims

CLAIMSWhat is claimed is:1 . A method of making an optical fiber cable, comprising: extruding a material comprising a liquid crystal polymer around an optical fiber to form an optical fiber cable comprising the optical fiber surrounded by a layer comprising the liquid crystal polymer, and then heat treating the optical fiber cable at a temperature in a range of 10 C° to 100 C° below a melting temperature of the liquid crystal polymer for a time of at least five minutes.

2. The method of claim 1 , wherein the liquid crystal polymer comprises a thermotropic liquid crystal polymer.

3. The method of claim 1 or 2, wherein the heat treating is performed for a time of five minutes to 8 hours.

4. The method of any one of claims 1 to 3, wherein a reinforcing fiber is added in parallel with or in a helical wrap around the optical fiber during the extruding.

5. The method of any one of claims 1 to 3, wherein a reinforcing fiber is not added in parallel with the optical fiber during the extruding.

6. The method of any one of claims 1 to 5, further comprising co-extruding, in a second layer on the material comprising the liquid crystal polymer, or as a sea in which the material comprising the liquid crystal polymer exists as one or more islands, at least one material selected from the group consisting of polyethylene naphthalate (PEN), polyether ether ketone (PEEK), and polytetrafluoroethylene (PTFE).

7. The method of any one of claims 1 to 6, wherein, prior to the extruding, the optical fiber is a coated optical fiber comprising a glass fiber surrounded by a coating, and the extruding comprises extruding the material comprising the liquid crystal polymer around the coated optical fiber.

8. The method of claim 7, wherein the coating is an acrylate coating.

9. The method of any one of claims 1 to 6, wherein, prior to the extruding, the optical fiber is an uncoated optical fiber comprising a glass fiber that is not coated.

10. The method of any one of claims 1 to 9, wherein, prior to the extruding, the optical fiber has a diameter of 5 microns to 1000 microns.11 . The method of any one of claims 1 to 10, wherein, after the heat treating, the optical fiber cable has a diameter of 25 microns to 2500 microns.

12. The method of any one of claims 1 to 11 , wherein, after the heat treating, the layer comprising the liquid crystal polymer has a thickness of 10 microns to 1000 microns.

13. The method of any one of claims 1 to 12, wherein, after the heat treating, the optical fiber cable has a break load of at least 100 N.

14. The method of any one of claims 1 to 13, wherein the heat treating is performed in an atmosphere containing a reduced concentration of oxygen relative to air.

15. A method of making an optical fiber cable, comprising: extruding a material comprising a liquid crystal polymer around a plurality of optical fibers to form an optical fiber cable comprising the plurality of optical fibers surrounded by a layer comprising the liquid crystal polymer, and then heat treating the optical fiber cable at a temperature in a range of 10 C° to 100 C° below a melting temperature of the liquid crystal polymer for a time of at least five minutes.

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