System and method for forming wires and cables

Abstract

A system and method for manufacturing wire and cable products having polymeric cable assemblies is provided. The system and method includes increasing the stiffness of the polymeric cable assembly to reduce compression and deformation of the cable assembly during the manufacturing process. In some cases, the stiffness is temporarily increased prior to or during the process of creating a twisted pair, or during the process of cabling.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 547,793, filed November 8, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to communication cables, and more specifically to high-performance communication cables and methods for manufacturing such cables. Background Technology

[0004] Various methods can be used to transmit power or signals. The inventions disclosed herein generally focus on wire and cable products that utilize insulated conductors to transmit current. Summary of the Invention

[0005] Technical issues

[0006] Many factors must be considered when designing conductors and cables. Applications such as Ethernet, CATV, and factory-floor based systems can dictate certain design characteristics such as size, electrical properties, and physical attributes. In terms of size, cable fit in standard connections, conduits, raceways, and ducts can be important. For electrical properties, capacitance, inductance, DC resistance, current, and voltage carrying capacity are design considerations. For certain specialized high-bandwidth cables, additional electrical parameters such as attenuation, propagation speed, delay skew, impedance, insertion loss, and noise reduction may be important. For physical attributes, flame and smoke resistance, chemical resistance, ozone resistance, moisture resistance, and / or pull-out strength are common properties that need to be considered. Fortunately, many tools and equations are available to assist design engineers in considering the best options for constructing conductors and cables.

[0007] The manufacturing process for conductors and cables is inherently continuous. Continuous production lines typically include a pay-out, where material is released or dispensed to initiate the line process. Accumulators may be present to help retain a portion of the material being released, ensuring a consistent line speed. A collection point, which may also have accumulators, is usually located at the end of the line process to allow the manufactured products to be produced at a consistent line speed and to collect the finished products onto rollers or other forms of packaging. These types of operations can include insulation, twisting, cabling, braiding, jacketing, and building conductors and cables to predetermined lengths. For most conductors and cables, the first step is the insulation process. This involves coating or covering the conductor with a polymer material to electrically insulate it.

[0008] During and after insulation, forces are likely to be encountered that can affect the final product's ability to meet expected specifications. For example, in the case of coaxial cables, it is desirable to add foil and / or metal braiding to protect the inner insulation layer and the electrical signals contained within it. It is well known that metal braiding can create indentations along the surface of the insulation material it wraps around. In other words, the bare strands of the braided shield will deform the surface of the underlying insulation material because the surface of the insulation material is typically softer than the metal wires applied to it. These deformations in the insulation material can affect the final cable's ability to transmit signals as capacitance and insertion loss increase. To address these indentations, design engineers can add additional insulation material to adjust the indentation depth.

[0009] In the case of multi-conductor cables, the various insulated conductors are brought together by twisting mechanisms commonly known as twisters, bundlers, or cablers. The forces encountered in the various mechanisms within these structures can compress and deform the polymer assembly of the cable. Again, cable designers will likely increase insulation to compensate for any compression, thereby increasing the size, weight, fuel load, and cost of the final product. Similar compressive forces may occur during sheathing and construction operations. To compensate for any deformation caused by compressive forces, thicker and / or stiffer sheath and insulation layers can be used, which increases the size and cost of the final product.

[0010] Sometimes, adverse forces or compressive forces acting on cable assemblies can be cyclic in nature. For example, if a wheel is not properly aligned, it may wobble back and forth as it moves laterally in a circular rotation. This can produce sinusoidal deformation of the material. If this sinusoidal pattern matches the intended frequency of the application (or any of its harmonics), it can compromise signal integrity. Existing methods to help reduce the effects of such forces, whether inherently uniform or sinusoidal, include reducing production line speed. Speed ​​can be reduced to mitigate and decrease the compressive forces induced by manufacturing equipment during product manufacturing. For this purpose, equipment is typically operated at a portion of its potential speed. However, this is undesirable because the equipment cannot be utilized to its full potential.

[0011] Another way compressive force can potentially cause problems is through capacitance targets. Capacitance is a function of the distance between metal surfaces and the properties of the materials between those surfaces. In the case of wires and cables, conductive surfaces can particularly include two conductors in close proximity or a shield and conductor in close proximity. The distance between these conductive surfaces is a critical design consideration in the manufacture of wire and cable products. Therefore, it is important to ensure that the appropriate conductor-to-conductor distance is achieved.

[0012] In some implementations, two insulated conductors are formed together to create a twisted pair. Similarly, multiple insulated conductors can be formed together to create a multi-conductor cable unit. When two insulated conductors are twisted together, a helical pattern is achieved along the length of the twisted pair unit. A twisted pair unit typically consists of metallic conductors, insulating material, and air or other gases contained in the gap between two generally circular insulated conductors or in the pores of foam insulation. Air is known to be an ideal dielectric material. For example, air has a dielectric constant of 1.0, while materials such as polyolefins typically have a dielectric constant range between 2.3 and 2.6. Therefore, the more air contained in the gap between the twisted pair units or in the pores of the foam insulation, the more desirable the electrical performance in the resulting cable. However, when the compressive forces encountered during cabling bring these insulated conductors closer together, the insulation deforms and shifts, reducing the total air content. This can result in higher, generally undesirable capacitance, and in some cases, a reduced signal speed that can decrease signal propagation capability.

[0013] Insulated conductors (such as twisted-pair communication cables) are used for high-frequency signal transmission, typically in plenum areas of buildings. In twisted-pair data cable implementations, individual conductors are insulated with polymer, and then two such insulated conductors are twisted together to form a single twisted pair. Twisted-pair cables are typically composed of multiple twisted pairs enclosed within a single outer sheath to form the cable. The individual twisted pairs within the cable can be twisted at different lay lengths (typically measured in mm per turn) to reduce electrical coupling (i.e., crosstalk) between adjacent twisted pairs.

[0014] The process of twisting individual insulated conductors together typically compresses the polymer insulation layer. The magnitude of the compressive force varies depending on the twisting equipment and the tightness of the twist (i.e., the number of turns per inch). The compressive force caused by twisting the insulated conductors results in deformation of the insulation layer separating the two conductors and a reduction in the thickness of the insulation layer. In some cases, compression leads to the loss of air content from the foam insulation material's cells or from the gaps in the twisted pair.

[0015] To compensate for this undesirable loss in insulation thickness and air content, polymer-insulated conductor manufacturers typically increase the thickness of the polymer insulation material. Generally, the shorter the twist pitch or the tighter the twist of the twisted pair, the greater the compression or squeezing of the polymer insulation material (whether foam or solid). Some twisted pairs are designed to have an impedance of approximately 100 ohms. The center-to-center spacing of the conductors within the twisted pair is a key factor affecting impedance. Therefore, because the increased compression brings the conductors closer together, additional insulation thickness is required to maintain the desired conductor-to-conductor spacing and impedance as the twist pitch becomes shorter. Increasing the amount of polymer insulation material leads to an increase in total cable weight, fuel load, cable size, and cost.

[0016] It should also be mentioned that in the case of torque (a type of force encountered when insulated conductors are twisted together), deformation can be uneven. This is because the insulation material may shift disproportionately depending on the direction of the torque. This is particularly undesirable in balanced pair applications. For example, in some applications involving twisted-pair units with two insulated conductors, it is desirable that the signal in each conductor of the two insulated conductors is a mirror image of the signal in the other conductor. In this way, electrical noise coupled to the individual insulated conductors of the twisted-pair unit is coupled in the same way, allowing electronic filtering mechanisms to cancel out noise elements. When the shape of one of the insulated conductors in a pair is disproportionate, subtracting any noise elements from the desired signal becomes challenging. Typically, conductor and cable products have both near-end crosstalk specifications and far-end crosstalk specifications to ensure that the amount of noise between the transmission pairs is low enough not to impede signal transmission. If the insulated conductors are not well balanced, meeting these specifications becomes even more difficult.

[0017] When cable designers consider how much additional insulation material is needed to compensate for any insulation displacement or deformation caused by forces encountered during manufacturing, the hardness of the insulation material should be understood. Hardness measures a material's resistance to surface deformation. In other words, hardness is the resistance to localized surface deformation. Indentation hardness can be measured using various methods, including Britnell, Meyer, Vickers, Rockwell, and / or Shore hardness testers. For polymeric materials such as fluorinated ethylene propylene (FEP), polyethylene (PE), flame-retardant polyethylene (FRPE), polypropylene (PP), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyvinyl chloride (PVC), etc., the Shore D hardness scale is typically used. For other materials such as rubber, other Shore scales, such as Shore A, may be used. In the case of Shore D, the test protocol is defined in ASTM D2240 and / or ISO 868 and will be used as the baseline hardness reference in this document.

[0018] It should be understood that variations in ambient temperature conditions can affect the hardness of materials. For example, in warm weather climates, during months when ambient temperatures are seasonally higher and thus reduce the hardness of any polymer materials used in the production facility, temperature control in the production facility may be necessary. Additionally, heat is generated within the cable assembly when it is subjected to compressive, torsional, or other deforming forces. In some applications, the forces involved increase the temperature of the assembly above ambient temperature as it deforms, thereby reducing the assembly's hardness and increasing its sensitivity to deformation during the deformation event and any subsequent deformation events.

[0019] Conversely, if the composite is cooled below ambient temperature, its hardness can increase. This hardening makes the material more resistant to compressive forces that can deform or indent the material.

[0020] Hardness conditioning does not always need to continue beyond the compression event. For some compression events, hardness conditioning can be applied before or during the compression event. When the compression event ends, the material can be allowed to return to its ambient hardness.

[0021] In industrial applications, there is a desire for a method to harden the compound or reduce the applied compressive force at a cost lower than that of adding insulation to counteract the effects of deformation in polymer cable assemblies. It is also desirable that any method incorporated to reduce the effect of compressive force on the insulation can be adapted to the current machine footprint with minimal modification to the positioning of the equipment itself. One such method is to control the temperature of the compound to produce a hardness shift in the compound. It is understood that a harder compound is less affected by a given compressive force than a softer compound. When using the Shore D scale, a higher number indicates a harder state of the compound.

[0022] Increasing the stiffness of polymer cable assemblies can reduce deformation of the polymer insulation, cross-linking filler, polymer tubing, or other polymer cable assemblies. This deformation is typically caused by compressive or torsional forces during manufacturing operations such as twisting, braiding, and the operation of mechanical devices (e.g., sheaves and take-up devices).

[0023] A new method and apparatus are needed to control the deformation of the insulation layer during cable manufacturing to produce polymer-insulated cables that maintain the desired conductor spacing by controlling the amount of insulated conductors compressed together during manufacturing. Controlling the deformation can help maintain the desired impedance and other electrical and mechanical properties before and after twisting.

[0024] Problem Solving Methods

[0025] This disclosure generally relates to conductor and cable products and to creating conductor and cable products with reduced deformation. Some embodiments incorporate methods for altering material stiffness. Some disclosed embodiments relate to methods for adjusting the stiffness of polymer cable assemblies (e.g., insulation materials), which can be used online as part of a continuous or semi-continuous manufacturing process.

[0026] Some disclosed embodiments relate to a communication cable comprising: at least one twisted pair of insulated conductors, wherein the insulated conductor comprises a conductor and an insulating layer surrounding the periphery of the conductor, and wherein the insulating layer comprises a foamed polymer having foam pores having a large diameter and a small diameter, and wherein a cross-section of the insulating layer shows that at least 50% of the foam pores have a small diameter greater than or equal to 80% of the large diameter.

[0027] According to exemplary embodiments of this disclosure, a method for controlling the effect of compressive force on a polymer cable assembly is provided. The polymer cable assembly may have a first hardness, which may be the hardness of the polymer cable assembly under environmental conditions. The method may include temporarily or permanently changing the hardness of the polymer cable assembly to a second hardness different from the first hardness. In some examples, the polymer cable assembly may be processed by a twisting unit, wherein the polymer cable assembly can withstand compressive force. The method may include allowing the polymer cable assembly to return to the first hardness.

[0028] According to another exemplary embodiment of this disclosure, a method for manufacturing a communication cable is provided. The method may include providing a polymer cable assembly. The polymer cable assembly may have a first cross-sectional radius and a second cross-sectional radius. The first cross-section may be the maximum distance along the cross-section from the center of the polymer cable assembly to the edge of the polymer cable assembly. The second cross-section may be the minimum distance along the cross-section from the center of the polymer cable assembly to the edge of the polymer cable assembly. Under environmental conditions, the first cross-sectional radius may be approximately equal to the second cross-sectional radius ±3%. Under environmental conditions, the polymer cable assembly may have a first stiffness. The method may include temporarily changing the stiffness of the polymer cable assembly to a second stiffness. In some examples, the second stiffness may be greater than the first stiffness. The polymer cable assembly may be processed in a twisted unit having an arc shape. The method may include subjecting the polymer cable assembly to a compressive force within the twisted unit. After this compressive force, in some embodiments, the first cross-sectional radius is approximately equal to the second cross-sectional radius ±10%.

[0029] In another exemplary embodiment of this disclosure, a method for manufacturing a communication cable is provided. The method may include providing a polymer cable assembly having a first diameter and a second diameter. The first diameter may be perpendicular to the second diameter ±3%. The polymer cable assembly may have a first stiffness, which is the stiffness of the polymer cable assembly under environmental conditions. The method may include temporarily changing the stiffness of the polymer cable assembly to a second stiffness, which may be greater than the first stiffness. The method may include processing the polymer cable assembly in a twisting unit having a bow. The method may include subjecting the polymer cable assembly to a compressive force. After the compressive force is applied, the first diameter may differ from the second diameter by no more than 10%. The method may include allowing the polymer cable assembly to return to the first stiffness.

[0030] In another exemplary embodiment of this disclosure, a method for manufacturing a communication cable is provided. The method may include providing a first pair of polymer-insulated conductors, a second pair of polymer-insulated conductors, a third pair of polymer-insulated conductors, and a fourth pair of polymer-insulated conductors. Each pair of polymer-insulated conductors may include two polymer-insulated conductors. Each polymer-insulated conductor may have a first hardness, which may be the hardness of the polymer-insulated conductor under environmental conditions. The method may include temporarily changing the hardness of one of the polymer-insulated conductors in the first pair, second pair, third pair, and / or fourth pair to a second hardness, which may be a hardness different from the first hardness. The method may include twisting the polymer-insulated conductors of the first pair together to form a first twisted pair. The first twisted pair may have a first propagation delay of 100 meters. The method may include twisting the polymer-insulated conductors of the second pair together to form a second twisted pair. The second twisted pair may have a second propagation delay of 100 meters. The method may include twisting the polymer-insulated conductors of the third pair together to form a third twisted pair. The third twisted pair may have a third propagation delay of 100 meters. The method may include twisting a fourth pair of polymer-insulated conductors together to form a fourth twisted pair. The fourth twisted pair may have a fourth propagation delay over 100 meters. For the first, second, third, and fourth propagation delays over 100 meters, the difference between the propagation delays over 100 meters may be within 50 nanoseconds.

[0031] In at least some examples, the hardness variation between the first hardness and the second hardness of the polymer cable assembly and / or the polymer insulated conductor can be between about 5% and about 95%. In some examples, the hardness variation between the first hardness and the second hardness of the polymer cable assembly and / or the polymer insulated conductor can preferably be between about 25% and about 75%. In some examples, the hardness variation between the first hardness and the second hardness of the polymer cable assembly and / or the polymer insulated conductor can more preferably be between about 35% and about 65%.

[0032] Some implementations involve cables utilizing both foamed polymer insulation and solid polymer insulation. In such implementations, the cable delay difference can be adjusted by controlling the ratio of foamed polymer insulation to solid polymer insulation.

[0033] Some implementations involve cables designed or configured to pass the NFPA 262 Steiner Tunnel Flame Test.

[0034] Some disclosed implementations involve cables with an extension length greater than 100 meters.

[0035] Some implementations involve a cable that includes any of the above-described cables or twisted pairs.

[0036] Some disclosed embodiments relate to methods of manufacturing communication cables to reduce deformation of polymer cable assemblies and maintain the roundness of insulated conductors and other cable assemblies.

[0037] The disclosed invention can be applied to any form of polymer cable assembly or cable construction, including, for example: solid, foam, profile extrusion, insulation layer, hollow tube, cross-link, rod filler, film, tape, coaxial construction involving braiding process, and / or multilayer insulation material.

[0038] In addition to reducing the deformation of the insulation layer when twisting insulated wires into twisted pairs, the disclosed invention can also be used to reduce the deformation of any polymeric material exposed to compressive forces (for example, braid indentations or mechanical systems such as take-up devices, pulleys, or wheels).

[0039] The above is a simplified summary to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an exhaustive overview. It is not intended to identify key / important elements or to describe the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that follows. Attached Figure Description

[0040] The accompanying drawings are incorporated in and form a part of this specification. The drawings illustrate various aspects of this disclosure and, together with the description, serve to illustrate the principles of this disclosure.

[0041] Figure 1 A schematic cross-sectional view illustrating an embodiment of the insulated conductor according to the present disclosure is shown.

[0042] Figure 2A and Figure 2B A schematic cross-sectional view illustrating an embodiment of a twisted pair cable is shown.

[0043] Figure 3 A schematic cross-sectional view illustrating an embodiment of the insulated conductor according to the present disclosure is shown.

[0044] Figure 4 A schematic diagram illustrating an embodiment of an insulated conductor according to the present disclosure is shown.

[0045] Figure 5 The graph shows the OD collapse rate of different strand pitches for solid, FS, and foam-insulated twisted pairs at ambient temperature.

[0046] Figure 6The graph shows the OD collapse rate of solid FEP insulated conductors twisted under ambient conditions and foam and FS insulated conductors twisted after curing.

[0047] Figure 7 A graph showing the impedance (ohms) variation between foam FEP insulated conductors twisted with different pitches (mm) and solid FEP insulated conductors is shown.

[0048] Figure 8 A graph showing the impedance difference (ohms) between FS insulated conductors and solid insulated conductors at different strand pitches (mm) is presented.

[0049] Figure 9 A graph comparing the impedance values ​​(ohms) of twisted pairs twisted at 2000 TPM or 2500 TPM at various twist pitches (mm) is shown.

[0050] Figure 10 A graph comparing the delay (ns) of various twisted pairs is shown.

[0051] Figures 11A to 11D A SEM image of a cross-section of the foam FEP insulation layer of a twisted pair is shown, the twisted pair being twisted at 2500 TPM with a pitch of 8.2 mm under ambient conditions.

[0052] Figures 12A to 12D SEM images of a cross section of the foam FEP insulation layer of a twisted pair are shown, which is twisted at 2500 TPM with a pitch of 8.2 mm after curing.

[0053] Figures 13A to 13C A schematic diagram of the cross-section of a foam-insulated twisted pair is shown. Detailed Implementation

[0054] The embodiments described below illustrate the necessary information to enable those skilled in the art to practice this disclosure and demonstrate the best mode of practice. When reading the following description in view of the accompanying drawings, those skilled in the art will understand the concepts of this disclosure and will recognize the application of these concepts, which are not particularly focused on herein. It should be understood that these concepts and applications fall within the scope of this disclosure and the appended claims.

[0055] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that, unless so explicitly defined herein, terms such as those defined in common dictionaries shall be interpreted as having a meaning consistent with their meaning in the context of this specification, and not in an idealized or overly formalized sense. For the sake of brevity or clarity, well-known functions or constructions may not be described in detail.

[0056] The terms "approximately" and "approximately" generally refer to the acceptable degree of error or variation in a quantity measured given the nature or precision of the measurement. Typically, exemplary degrees of error or variation are within 20% of a given value or range, preferably within 10%, and more preferably within 5%. Unless otherwise stated, the numerical quantities given in this specification are approximate, meaning that the terms "approximately" or "approximately" can be inferred when not explicitly stated. Unless otherwise stated, the numerical quantities in the claims are precise.

[0057] It should be understood that when a feature or element is referred to as "on another feature or element," it can be directly on the other feature or element, or there may be intermediate features and / or elements present. Conversely, when a feature or element is referred to as "directly on another feature or element," there are no intermediate features or elements. It should also be understood that when a feature or element is referred to as "connected to," "attached to," or "linked to" another feature or element, the feature or element can be directly connected to, attached to, or linked to the other feature or element, or there may be intermediate features or elements present. Conversely, when a feature or element is referred to as "directly connected to," "directly attached to," or "directly linked to" another feature or element, there are no intermediate features or elements. Although described or illustrated with respect to one embodiment, the features and elements thus described or illustrated can be applied to other embodiments.

[0058] The terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms.

[0059] The terms “first,” “second,” etc., are used herein to describe various features or elements, but these features or elements should not be limited by these terms. These terms are used only to distinguish one feature or element from another. Therefore, without departing from the teachings of this disclosure, the first feature or element discussed below may be referred to as the second feature or element, and similarly, the second feature or element discussed below may be referred to as the first feature or element.

[0060] In some places, standard methods, such as, but not limited to, measurement methods, are referenced. It should be understood that such standards are revised from time to time, and unless otherwise expressly stated, references to such standards in this disclosure must be interpreted as referring to the most recently published standard at the time of submission.

[0061] This disclosure describes conductor and cable products with improved electrical properties and / or improved manufacturing characteristics, as well as embodiments of methods and systems for manufacturing conductor and cable products. While the disclosed invention is generally discussed in the context of twisted polymer insulated conductors to form twisted pairs, it should be appreciated that the disclosed invention is applicable to many applications beyond twisted insulated conductors, including, for example, polymer insulation layers, foam insulation layers, solid insulation layers, foam sheaths, cross-links, polymer tapes, hollow tubes, rod-shaped fillers, sheaths, and other polymer cable assemblies. The following disclosure frequently refers to insulated conductors, which include polymer assemblies used as insulating material surrounding conductive components, typically conductive metal wires such as copper or copper alloys. However, the subject matter described herein can also be applied to polymer assemblies in other contexts.

[0062] In some examples, this disclosure refers to environmental conditions. Environmental conditions refer to temperature, humidity, and atmospheric pressure conditions that typically occur in indoor spaces.

[0063] When polymer-insulated conductors are subjected to compressive forces, such as when wires are twisted to form a twisted pair, the polymer insulation assembly can be compressed or otherwise deformed. For polymer insulation layers, this deformation can disrupt the conductor-to-conductor spacing and affect the electrical properties of the wires or the resulting cable. For foam insulation materials, this compression can alter the size, shape, aspect ratio, and / or volume of the cells within the foam insulation material.

[0064] In some embodiments, the polymer insulating layer or a portion thereof may be a foamed polymer. In such embodiments, the foamed polymer insulating material comprises numerous small cavities of air or other gases. These cavities are commonly referred to as foam cells. Air is known to be an excellent electrical insulator, therefore introducing cavitation throughout the polymer insulating layer reduces the dielectric constant of the insulating layer. This is because the dielectric constant of air is 1.0, which is preferred over other materials such as FEP (2.0), polyethylene (2.3), and polyvinyl chloride (3.5).

[0065] While air possesses excellent dielectric properties, it does not provide mechanical hardness. Therefore, foam materials or other polymer components incorporating air will have lower hardness than similar components without air. Because air can be introduced into polymer cable assemblies in any number of ways (small pores, large pores, cavities, gaps, etc.), the final strength will decrease depending on the percentage of air replacing the solid polymer and the size of the air cavities used. In some embodiments, the methods described herein for increasing hardness can be used to increase the hardness of the remaining polymer material in the polymer foam that has not been replaced by air.

[0066] Because foamed polymers are more easily deformed than solid polymers, the amount of additional material added to counteract deformation can be increased. In some embodiments, the Shore D hardness of the foamed polymer material increases by at least about 10% relative to similar materials at 20°C before or during a compression event.

[0067] Figure 1 A cross-section of an insulated wire having a polymer insulation layer 110 surrounding a conductor 120 is schematically illustrated. When the insulated wire is subjected to compressive force, the insulation layer 110 may deform. The degree of deformation of the insulation layer 110 can be described by the extrusion ratio. The extrusion ratio is defined as the deformation length / original OD. 100 is expressed as a percentage.

[0068] Figure 2A The cross-sections of two insulated wires are schematically illustrated, each having a polymer insulation layer 210 surrounding a conductor 220. Figure 2A Two insulated wires are shown in contact with each other, and the circular polymer insulation layer has not been deformed. Figure 2A The shaded area of ​​the polymer insulation layer 210 illustrates the region that deforms due to compressive force when two conductors are twisted together. Insulated conductors are commonly referred to as monomers or insulating monomers.

[0069] Figure 2B The cross-sections of two insulated wires are schematically illustrated, each having a polymer insulation layer 210 surrounding conductor 220. Figure 2B This example illustrates two wires that come into contact with each other after compressive force has caused deformation in the polymer insulation layer.

[0070] Will Figure 2B The conductor-to-conductor distance in the compressed wire and Figure 2A A comparison of conductor-to-conductor distances in uncompressed wires shows that the distance between the two conductors decreases due to deformation of the two insulation layers. This type of compression can occur when the wires are twisted together or during other compression events. This reduction in conductor-to-conductor distance negatively impacts the electrical performance of twisted pairs and any resulting cable.

[0071] One of the benefits of the disclosed invention is the ability to produce twisted-pair and / or other cable designs with improved electrical properties by increasing stiffness and reducing the amount of deformation generated during twisting, cabling, and / or manufacturing. One source of deformation in the insulation layer of a twisted pair is the twisting process, which involves twisting the two insulated conductors together. The degree of deformation that occurs during twisting is influenced by several factors, including, for example, the strand pitch, wire tension, the insulation material, the stiffness of the insulation material, and / or the heat generated within the polymer insulation material during twisting. To minimize deformation, increasing the stiffness of the insulation material during twisting may be desirable when the insulated conductors are subjected to maximum deformation forces. As discussed, one way to temporarily increase the stiffness of the insulation layer is to lower the temperature. In some embodiments, it is desirable to lower the temperature of the insulation layer while the conductors are being twisted.

[0072] The forces applied to polymer cable assemblies depend on the type and manufacturer of equipment used by any particular conductor and cable company. For example, there are many different types of cabling machines. Each of these machines will exert unique forces on the various components being cabled. When conductor and cable manufacturers determine how much additional insulation to incorporate into the design to compensate for deformation, this is largely empirical, combined with knowledge of the material's stiffness, which ultimately determines the amount of additional insulation required.

[0073] In industry, the term "wall thickness" is used to describe the amount of insulation and / or sheathing material required to produce the desired product. Most application designs will have an absolute minimum wall thickness, an average minimum wall thickness, a nominal wall thickness, and an absolute maximum wall thickness. The nominal wall thickness is typically considered when compensating for deformation and dents in the insulation.

[0074] The softer the insulation material, the greater the amount of additional wall thickness typically required to compensate for the loss of wall thickness due to compression under a given set of conditions. For example, FEP is a softer insulation material than HDPE or PP and requires a larger amount of additional insulation. Understanding the stiffness of the insulation material is useful for determining the required amount of compensation. If the amount of deformation is controlled, the amount of additional insulation required can be reduced. This will benefit both the size and cost of the final product. In some implementations, the amount of additional insulation added to produce the desired cable is reduced by at least about 0.0005 inches, or at least about 0.001 inches, at least about 0.003 inches, at least about 0.005 inches, or at least about 0.01 inches, compared to cables produced under the same conditions but without using the hardening techniques described herein.

[0075] Compared to insulation layers made from stiffer polymers, softer insulating polymers (such as fluorinated ethylene propylene (FEP)) are more likely to deform when force is applied to the insulation layer. Foam insulation layers can also deform more easily than solid polymers.

[0076] The resistance to deformation of an insulating layer can typically be measured or described by the hardness of the insulating material. As discussed, hardness is a measure of resistance to localized deformation caused by mechanical indentation or abrasion. Generally, different materials exhibit different hardnesses under varying environmental conditions.

[0077] One way to control the hardness and stress / strain response of a polymer insulation layer is to regulate the temperature of the polymer material. This temperature regulation can be achieved by any reasonable method, such as directly or indirectly exposing the insulation layer to freezing, ambient, or heated fluids (such as liquids or gases). In some embodiments, the polymer cable assembly can be exposed to frozen water or aqueous solutions. In some embodiments, the polymer cable assembly can be exposed to cryogenic fluids, such as liquid nitrogen. In some embodiments, the polymer cable assembly can be exposed to frozen gases or vapors. In some embodiments, the polymer cable assembly can be exposed to one or more frozen wheels, rollers, tubes, or other solid surfaces. In some embodiments, the polymer cable assembly can be indirectly cooled. For example, the polymer cable assembly can pass through the interior of a tube while the exterior of the tube is being cooled. The atmosphere inside the tube will be frozen, thereby cooling the polymer cable assembly. The inventions described herein are generally described in the context of cryogenic fluids, but any of these methods can or alternatively be used.

[0078] Figure 3 A cross-section of an insulated wire having a polymer insulation layer surrounding conductor 340 is schematically illustrated. Figure 3 The insulating layer in the depicted embodiment is a single, uniform polymer layer; however, for clarity, Figure 3 A uniform insulating layer divided into discrete concentric portions is shown. The outer surface 310 of the polymer insulating layer is typically exposed to the external environment and is the first to experience any external compressive force. The outer portion 320 of the insulating layer lies directly beneath the outer surface. The inner body 330 of the insulating layer surrounds the conductor 340 and experiences minimal external compressive force because the outer surface 310 and the outer portion 320 of the insulating layer must deform before impacting the inner body 330.

[0079] When a polymer-insulated wire is exposed to a freezing liquid or cryogenic fluid (e.g., liquid nitrogen), the outer surface 310 cools rapidly upon direct contact with the cryogenic fluid. Subsequently, the outer portion 320 of the insulation layer cools as heat is carried away from the insulation and into the cryogenic fluid. The rate of cooling of the outer portion of the insulation layer will vary based on the thermal conductivity of the polymer material forming the insulation layer. The inner body 330 of the insulation layer will cool after the outer surface and outer portion have cooled. It should be understood that a temperature gradient, rather than a sharp line, will form to separate the outer portion 320 from the inner body 330.

[0080] As the outer surface and outer portions of the insulation layer cool, the stress / strain response of these portions can increase. In some embodiments, this creates a hardened outer portion of the insulation layer that surrounds the relatively less cooled or relatively high-temperature inner body of the insulation layer. If the insulation layer remains in contact with a cryogenic fluid for a sufficiently long time, then eventually the entire body of the insulation layer can be cooled, and the overall hardness of the insulation layer can increase.

[0081] It should be recognized that when a polymer-insulated conductor is removed from a cryogenic fluid or other cooling medium and exposed to the ambient atmosphere, the polymer insulation material will begin to recover to ambient temperature. As temperature increases, the stiffness and stress / strain response of the polymer insulation material decrease, and the polymer insulation material becomes more susceptible to deformation under compressive forces. In some embodiments of the disclosed invention, one or more polymer insulation layers are cooled shortly before undergoing a compressive event (e.g., twisting to form a twisted pair). In some applications, the speed at which the insulated conductor is moving and the distance between the cooling container and the twisting take-up device will determine the time the polymer-insulated conductor is exposed to the ambient atmosphere after cooling but before undergoing compressive forces. In some embodiments, the end of the cooling container is less than 10 feet from the point where the polymer-insulated conductor subsequently undergoes compressive forces. In some embodiments, the end of the cooling container is less than 8 feet, 6 feet, 4 feet, or 2 feet from the point where the polymer-insulated conductor subsequently undergoes compressive forces.

[0082] It should be understood that the disclosed invention does not require a permanent alteration of the composition of the polymer insulating material. The composition of the polymer insulating layer remains unchanged when the polymer insulating material is cooled, thus altering the stress / strain response. As the insulating layer is subjected to any compressive or deformable force and as the polymer insulating layer is allowed to recover to ambient temperature, the composition of the polymer insulating layer remains unchanged, thus reducing its stiffness.

[0083] Figure 4A cross-section of an embodiment in which the conductor is insulated by multiple insulating layers is schematically illustrated. In some embodiments, multiple layers of different insulating materials may be used to surround the conductor. In some embodiments, an outer material layer with higher inherent hardness may be used to help reduce compression of the softer inner material layer. In some embodiments, a foam insulation layer 420 may be used to insulate the conductor 410. The hardness of the foam insulation layer may be significantly lower than that of a solid insulation layer of the same polymer material because the foam insulation layer contains many discontinuous cavities. Therefore, the foam insulation layer is more susceptible to compression during manufacturing. A surface layer 430 made of a material harder than the underlying foam insulation material 420 may be used to reduce the compression of the foam insulation material. The hardness of the outer portion of the insulation material may be temporarily increased to reduce compression or deformation of the insulation layer during manufacturing or cable splicing. It should be understood that the entire thickness of the inner foam insulation layer may not need to be hardened to give the outer portion of the foam insulation layer a temporarily increased hardness and resistance to compression during cabling. It should also be understood that the surface layer 430 may or may not be foam itself. In some embodiments, the skin will be a solid polymer designed to protect the underlying foam insulation layer. In some implementations, the surface layer will comprise a polymer different from the underlying insulating layer.

[0084] In one illustrative example, three different twisted pairs were created using a twisting machine set to 2500 turns / minute with fluorinated ethylene propylene (FEP) insulated conductors. The twist pitch varied between approximately 6 mm and approximately 20 mm for the different samples. The different twisted pairs included conductors fully insulated with solid FEP (“solid”); conductors insulated with an inner layer of foam FEP and an outer layer of solid FEP (“foam skin” or “FS”); and conductors insulated only with foam FEP (“foam”). Figures 4 to 7 The outer diameter of the insulating monomers discussed in the text is the same before twisting.

[0085] The OD collapse rate compares the outer diameter (“OD”) of the twisted pair to that of a hypothetical twisted pair that has undergone zero compression or deformation. This can be used to quantify the amount of deformation that occurs during twisting. The OD of the assumed twisted pair is calculated as twice the OD of a single cell of the original insulation before twisting. The OD collapse rate is calculated using the following formula:

[0086] Figure 5 The graph shows the OD collapse rate for different strand pitches of solid, FS, and foam-insulated twisted pairs at ambient temperature. From Figure 5As can be seen, the OD collapse rate is usually expressed as a negative number. When the twist pitch is short, the OD collapse rate usually has a large absolute value. This is reasonable because the compressive force is usually greater when the twist pitch is short. Under environmental conditions, solid FEP insulation has significantly less collapse across all twist pitches compared to foam or FS insulated twisted pairs.

[0087] Figure 6 The diagram shows the OD collapse rate of solid FEP insulated conductors twisted under ambient conditions and foam and FS insulated conductors twisted after curing. In this embodiment, the foam and FS insulated conductors were exposed to liquid nitrogen for approximately 1 to 15 seconds before twisting.

[0088] from Figure 6 As can be seen, the hardened foam-insulated conductor experienced significantly more deformation than the solid-insulated conductor twisted in its unhardened state. Conversely, when the strand pitch was between approximately 10 mm and approximately 14 mm, the hardened FS-insulated conductor exhibited an OD collapse rate similar to that of the solid-insulated conductor. This suggests that if the FS insulation material is hardened prior to a compression event such as twisting, the FS-insulated conductor can be utilized with a significantly reduced collapse rate.

[0089] Figure 7 A graph comparing the impedance (ohms) changes between foam FEP insulated conductors and solid FEP insulated conductors twisted at different pitches (mm) is shown. All twisted pairs in this embodiment are twisted at 2500 TPM. All solid FEP insulated samples were twisted under ambient conditions. The two X's in the graph indicate that the impedance of the sample is equal to the impedance of the solid FEP insulated conductor twisted under ambient conditions.

[0090] exist Figure 7 In the diagram, the dashed lines indicate that at a strand pitch of less than approximately 15 mm, the foam-insulated conductor twisted under ambient conditions exhibits a lower impedance than the solid-insulated conductor twisted under ambient conditions. When the strand pitch is greater than 15 mm, the compressive force is considered sufficiently low so that the enhanced electrical properties of the foam insulation material outweigh the compensation for the increased deformation experienced by the foam insulation material.

[0091] exist Figure 7 In the diagram, the dashed lines show that at a twist pitch greater than approximately 8 mm, the foam-insulated conductor hardened before twisting exhibits a higher impedance than the solid-insulated conductor twisted under ambient conditions. Unbound by theory, it is believed that the increased stiffness of the hardened foam insulation reduces the amount of deformation in the foam insulation layer, thus allowing for higher impedance values ​​in hardened foam-insulated twisted pairs over a wider range of twist pitches compared to solid-insulated twisted pairs.

[0092] exist Figure 7In the diagram, the solid line shows that the foam-insulated conductor cured before twisting has a greater impedance value than the foam-insulated conductor twisted under ambient conditions. The difference in impedance between the cured foam-insulated conductor and the ambient foam-insulated conductor decreases with increasing twist pitch.

[0093] Figure 8 A graph comparing the impedance difference (ohms) between FS insulated conductors and solid insulated conductors at different twist pitches (mm) is shown. All twisted pairs in this embodiment are twisted at 2500 TPM.

[0094] exist Figure 8 In the diagram, the dashed line indicates that, with a twist pitch of less than approximately 13 mm, the FS insulated conductor twisted under ambient conditions has a lower impedance value than the solid insulated conductor twisted under ambient conditions. Figure 8 The dashed lines in the diagram show that FS insulated conductors, hardened before twisting with a pitch greater than approximately 7.5 mm, have a greater impedance value than solid insulated conductors twisted under ambient conditions.

[0095] exist Figure 8 In the diagram, the solid lines show that, at a twist pitch of less than approximately 18 mm, FS insulated conductors hardened before twisting typically have a greater impedance than FS insulated conductors twisted under ambient conditions. The impedance difference between hardened FS insulated conductors and ambient FS insulated conductors generally decreases with increasing twist pitch.

[0096] Figure 8 It is shown that twisted pairs can be manufactured using hardened FS-insulated conductors or hardened foam-insulated conductors instead of ambient solid-insulated conductors to produce twisted pairs with greater impedance values ​​at twist pitches greater than about 7.5 mm. In some embodiments, if the insulation is hardened before twisting, less foam or FS insulation can be used to produce twisted pairs with similar electrical properties to solid-insulated twisted pairs.

[0097] Figure 9 A graph comparing the impedance values ​​(ohms) of twisted pairs twisted at 2000 TPM or 2500 TPM at various twist pitches (mm) is shown. Twisted pairs are also available at various twisting speeds, with or without the disclosed hardening technique.

[0098] from Figure 9As can be seen, at 2000 TPM and 2500 TPM, twisted-pair cables manufactured using hardening technology have higher impedance values ​​than those not manufactured using hardening technology. The highest impedance value was achieved at 2500 TPM. This is counterintuitive, as the twisting at higher TPMs results in greater compressive force, which typically leads to lower impedance values. When comparing twisted-pair cables manufactured under ambient conditions, they follow standard trends. When comparing twisted-pair cables manufactured using hardening technology, those manufactured at 2500 TPM have higher impedance values ​​than those manufactured at 2000 TPM. This improved electrical performance at higher TPMs allows for the development of cables manufactured at higher TPMs, faster line speeds, and / or with less total insulation material.

[0099] Figure 10 A graph comparing the delay (ns) of various twisted pairs twisted at 2000 TPM or 2500 TPM with twist pitches between 10.0 mm and 10.5 mm is shown. These samples were prepared with or without the disclosed curing technique.

[0100] from Figure 10 As can be seen, for samples manufactured at 2000 TPM and 2500 TPM, the twisted pair manufactured using the hardening technique exhibited reduced delay across all twist pitches. The greatest improvement was again observed in the sample twisted at 2500 TPM.

[0101] Figures 11A to 11D SEM images of a cross-section of the foam FEP insulation layer from twisted-pair cables twisted at 2500 TPM with a pitch of 8.2 mm under ambient conditions are shown. These figures also show cross-sectional images of the foam-insulated conductor, which has multiple cavities or foam cells distributed throughout the insulation layer. It is understood that these cavities are closed and do not allow air or any other fluid to pass through the insulation layer. As indicated by the arrows, the original circular shape of the cross-section shows a clear area where the insulation layer has been deformed by the compressive forces of twisting.

[0102] on the contrary, Figures 12A to 12D SEM images of a cross-section of the foam FEP insulation layer from twisted pairs of cables twisted at 2500 TPM with a pitch of 8.2 mm after curing are shown. As indicated by the arrows, the initial circular shape shows a significant reduction in the degree of deformation of the insulation layer when compressed during twisting.

[0103] Figures 13A to 13C A schematic diagram of the cross-section of a foam-insulated twisted pair is shown. Figure 13ATwo twisted pairs of cables manufactured under different conditions are shown. The upper twisted pair shows smaller diameter insulating monomers that are twisted after curing. The lower twisted pair shows larger diameter insulating monomers twisted under ambient conditions. After being twisted together, although the lower twisted pair utilizes larger diameter insulating monomers, the conductor-to-conductor spacing in the upper twisted pair is larger. Figure 13A It was also shown that the gaps in the upper twisted pair contained more air compared to the lower twisted pair.

[0104] Figure 13B The diagram illustrates the foam cells of two twisted-pair cables manufactured under different conditions. A schematic of the two twisted-pair cables shows the foam cells between the conductors being compressed during the twisting process. This region is referred to as the compression region. Conversely, in this example, even after twisting, the foam cells in the twisted pair that are not in the compression region remain generally uncompressed. This region is referred to as the uncompressed region. Typically, the compression region of a twisted-pair cable includes the portion of the insulation layer located between the two conductors. A key characteristic of the compression region is that the insulation layer is compressed significantly more in this region than in other uncompressed regions. In some embodiments, the compression region comprises approximately one-quarter of the cross-section of the insulation layer.

[0105] Figure 13B The diagram shows an upper twisted pair after curing and a lower twisted pair under ambient conditions. The foam cells in the compression region of the upper twisted pair are less compressed than those in the lower twisted pair. Since air has a lower dielectric constant than polymer insulation, the more air retained in the foam cells and gaps, the better the performance of the resulting twisted pair. Similarly, the less compressed the foam cells in the twisted pair, the better the performance of the resulting twisted pair. Less compressed twisted pairs also maintain a larger conductor-to-conductor spacing, which also benefits the electrical performance of the twisted pair and any resulting cable.

[0106] Figure 13C It shows the relationship with Figure 13B The same twisted pair, where the overlapping radial lines indicate that the compression zone may comprise approximately one-quarter of the insulation layer. In some embodiments, the compression zone is the area between the two conductors. In some embodiments, the compression zone is the area within approximately 45 degrees of the line drawn between the two conductors.

[0107] Although Figures 13A to 13C A schematic diagram of a twisted pair cable is shown, but it should be understood that the same concept applies to other foam polymer cable assemblies, such as fillers, cross-links, tapes, straws, etc.

[0108] In some implementations, reducing the compression or deformation of polymer-insulated conductors, cables, cable sheaths, and other cable assemblies allows for the use of less polymer material in the manufacture of those components while maintaining or improving electrical performance. By using less polymer material, the resulting twisted pairs and cables contain less flammable material and have a lower fuel load. Cables with a lower fuel load are more likely to pass the NFPA 262 Steiner Tunneling Flame Test.

[0109] In some implementations, the step of adding additional insulation and / or sheathing material to compensate for anticipated deformation introduces a new set of problems. For example, many cables must pass certain flame and smoke standards to ensure their safe use in buildings or residences. One factor contributing to a cable's tendency to propagate flame and generate smoke is the amount of combustible material contained within it, often referred to as "fuel load." Typically, when the amount of fuel (in this case, polymer insulation, sheathing, or other polymeric materials) increases, the result is more smoke generation and / or flame propagation from the cable being tested.

[0110] An example of fuel load testing is the NFPA 262 Steiner Tunnel Flame Test, which is related to ASTM E 84, NFPA 255, UL 723, and ULCS 102. In the NFPA 262 Steiner Tunnel Flame Test, a bundle of cables placed in a non-combustible horizontal box or tunnel is subjected to a flame. Standardized flame intensities are used, and air moves through the tunnel to simulate the conditions of a pressure ventilation system ceiling. Materials tested according to these standards must demonstrate a maximum flame spread distance of 5 feet, a maximum peak optical density of 0.5, and a maximum average optical density of 0.15.

[0111] Design engineers typically select materials optimized for cost and to meet required fuel load standards. Potential problems arise when additional materials are added to compensate for cable deformation caused by forces generated during cable manufacturing. This additional material increases fuel load, increases cost, and limits the types of materials that can be used. For example, some Category 6A cables use shorter strand pitches to achieve higher data speeds. These shorter strand pitches typically generate higher compressive forces during manufacturing. These cables typically use FEP resin for insulation due to the higher-than-normal deformation encountered during the manufacturing process. Some other Category 6 cables utilize longer strand pitches and experience relatively reduced compressive forces during manufacturing. Therefore, these cables require less additional insulation to compensate for deformation. This lower fuel load allows for the use of other, less expensive materials.

[0112] In some implementations, the cable is manufactured by temporarily increasing the stiffness of the polymer cable assembly before or during a compression event. The increased stiffness reduces the degree of deformation experienced during the compression event, thus requiring less additional insulation to achieve the desired electrical performance. In some implementations, increasing the stiffness of the polymer cable assembly allows for a reduction in the overall fuel load in the resulting cable, thereby allowing the cable to pass the NFPA 262 Steiner Tunneling Flame test, whereas a similar cable that does not undergo increased stiffness and includes additional polymer material to counteract the increased deformation would fail the NFPA 262 Steiner Tunneling Flame test.

[0113] In some embodiments, cables with lower fuel loads can be developed that would fail the NFPA 262 pilot tunnel flame test without reducing the fuel load. In some embodiments, cables manufactured using the disclosed techniques incorporate reduced fuel loads and propagate less flame or smoke.

[0114] In some implementations, cables created using the disclosed techniques can have a smaller outer diameter. This can allow for the retrofitting of existing buildings with modern high-performance cables having a diameter equal to or smaller than that of previously used lower-performance cables.

[0115] In some embodiments, the conductors and cables have a certain amount of polymer insulation material and / or other polymer components that contribute to their fuel load. In some embodiments, the fuel load is designed to produce a flame travel distance equal to or less than about 5 feet, a peak smoke density equal to or less than about 0.5, and / or an average smoke density equal to or less than about 0.15 (when measured according to NFPA 262 Steiner Tunnel Flame Test).

[0116] In some implementations, the polymer cable assembly is cooled and / or hardened prior to undergoing a compression event. Due to this hardening, the polymer cable assembly is able to provide the required electrical performance because it deforms less than a polymer cable assembly that has not been cooled and / or hardened prior to compression.

[0117] In some embodiments, the fuel-load-reducing wires and cables have a capacitance value of less than about 20 pF / ft. In some embodiments, the fuel-load-reducing wires and cables have an impedance value between about 50 ohms and 150 ohms, or between about 75 ohms and 125 ohms, or between about 85 ohms and 115 ohms, or equal to about 100 ohms. In some embodiments, the fuel-load-reducing wires and cables have a propagation speed between about 62% and 80% of the speed of light, or between about 66% and 70% of the speed of light.

[0118] The limiting oxygen index (“LOI”) is the minimum concentration of oxygen required to support combustion in a polymer, expressed as a percentage. Different polymers have different LOI values. The higher the LOI, the less flammable the polymer is generally. For example, polyethylene has an LOI of about 18%, flame-retardant polyethylene (FRPE) has an LOI of about 33%, and FEP has an LOI of about 90%. Therefore, cables made of FEP generally perform better in the NFPA 262 Steiner tunnel flame test compared to cables made of PE or FRPE.

[0119] For a given insulation wall thickness, foam-insulated cables use less total polymer insulation material because foam contains a significant amount of air as well as polymer. Because foam insulation contains less total polymer, foam-insulated conductors have a lower total fuel load. It should be noted that the total fuel load of a cable includes all other cable components such as tape, cross-linking, filler, inner sheath, and / or outer sheath.

[0120] Many cables comprise four twisted pairs of insulated conductors. In some embodiments, the cable comprises one, two, or three twisted pairs insulated with FEP, and the remaining twisted pairs are insulated with FRPE or other non-fluoropolymers. In some embodiments, such cables are Category 6A cables that have passed the NFPA 262 Steiner Tunneling Flame Test. Such cables can be manufactured using the disclosed hardening techniques, which can produce cables with low fuel loads while maintaining or improving the electrical properties of the cable.

[0121] In some implementations, cables containing four FRPE foam-insulated twisted pairs are Category 6A cables and have passed the NFPA 262 Steiner Tunneling Flame Test. In some implementations, the cable can be manufactured using one, two, three, or four foam-insulated twisted pairs by temporarily curing the foam FRPE insulation monomers before twisting them to form the twisted pairs. By curing the foam polymer insulation, the electrical performance of cables containing foam FRPE insulation can be improved to meet or exceed Category 6A performance standards for gas-filled rated cables. In some implementations, the use of polymer foam insulation reduces the overall fuel load of the cable, thereby allowing the cable to meet or exceed the NFPA 262 Steiner Tunneling Flame Test standard.

[0122] Communication cables are typically less than 100 meters in length. This distance is limited by propagation speed and cable attenuation loss. Using the disclosed hardening technology, the propagation speed and attenuation loss of the cable can be increased, thus allowing for longer cable lengths.

[0123] Communication cables typically have four twisted pairs, each with a different twist pitch. The electrical performance of the twisted pair with the shortest twist pitch or the tightest twist usually limits the total length of the cable. In some disclosed embodiments, the twisted pair with the shortest twist pitch is insulated with a foam polymer, and the twisted pair with the longest twist pitch is insulated with a solid polymer. By curing the foam polymer insulation material before twisting the insulated conductors to form the twisted pairs, the electrical performance of the resulting twisted pair can be improved, and the total length of the resulting cable can be extended. In some embodiments, the insulated conductors of one or more twisted pairs are insulated with a foam polymer, which is cured before twisting. Using the methods and techniques disclosed herein, cables with a data transmission rate of at least 10 gigabits per second at a frequency of at least 500 MHz can be constructed. In some embodiments, such cables can be at least 120 meters long, or at least 130 meters long, or at least 150 meters long. In some embodiments, the cable is a Category 6A cable, meaning that the cable meets the relevant Category 6A standard. In some implementations, at least one twisted pair within the cable has a twist pitch of less than approximately 8.2 mm.

[0124] In some implementations, by increasing the stiffness of the polymer-insulated conductor, the conductor will maintain a more rounded cross-section rather than deforming under compressive forces. This reduces the amount of surface-to-surface contact between the two polymer-insulated conductors and reduces friction or torque between the conductors.

[0125] In some implementations, the cable is manufactured without significantly deforming or only slightly deforming the polymer cable assembly incorporated into the cable. Many polymer cable assemblies have a generally circular cross-section with approximately equal large and small diameters. Similarly, before the cable is compressed or deformed, the generally circular cross-sections of many polymer cable assemblies will have many radii that are approximately equal to each other. More specifically, before the polymer cable assembly is compressed or deformed, the radius with the maximum length is approximately equal to the radius with the minimum length. Although there are some inherent variations in the wall thickness of polymer cable assemblies, the maximum and minimum radii typically differ from each other by less than 3%. In some polymer cable assemblies, the initial maximum and minimum radii may differ from each other by less than 5% before compression or deformation.

[0126] In some embodiments, the polymer cable assembly maintains a generally circular cross-section after being subjected to compressive or deformable forces. By increasing the stiffness of the polymer cable assembly as described herein, the polymer assembly can deform less, thereby maintaining its generally circular cross-section. In some embodiments, after the polymer cable assembly is subjected to compressive forces, the maximum and minimum length radii of the cable assembly differ from each other by about 10%. In some embodiments, the maximum and minimum length radii differ from each other by about 8% or about 5%. In some embodiments, the maximum and minimum length radii differ from each other by about 20%, about 15%, or about 12%. It should be understood that the closer the maximum and minimum length radii are to each other, the closer the cross-section is to a circle, and the less deformation the polymer cable assembly undergoes.

[0127] In some embodiments, the polymer-insulated conductor or other polymer cable assembly is cooled to increase rigidity before being subjected to compressive forces. In some embodiments, the reduced temperature of the polymer cable assembly compensates for any heat generated within the polymer cable assembly by the compressive forces. In some embodiments, the temperature of the polymer cable assembly during or immediately after a compression event is equal to or lower than ambient temperature.

[0128] In some embodiments, a twisted-pair cable is disclosed. The twisted-pair cable includes a pair of insulated conductors. Each insulated conductor includes a conductor and an insulating layer surrounding the periphery of the conductor. In some embodiments, the insulating layer includes a solid polymer layer. In some embodiments, the insulating layer includes a foamed polymer layer. In some embodiments, the insulating layer includes multiple layers of foam and / or solid polymer. In some embodiments, the insulating layer includes a foamed polymer having foam cells. A cross-section of the foamed polymer is shown, for which the foam cells have a large diameter and a small diameter. The large diameter is the maximum length diameter of the foam cell cross-section, and the small diameter is the minimum length diameter of the foam cell cross-section. Before exposure to a compression event, the large and small diameters of the foam cells typically differ by less than 10%. After experiencing compressive force, the foam insulation material and the foam cells typically deform, resulting in a larger difference between the large and small diameters. In some disclosed embodiments, the twisted pair has a foam insulation layer, wherein the cross-section of the twisted pair shows that at least about 50%, about 70%, about 80%, or about 90% of the foam cells have a smaller diameter length that is within 10%, 15%, or 20% of the larger diameter length.

[0129] In some disclosed embodiments, the cross-section of the twisted pair shows that at least about 50%, about 75%, about 85%, or about 95% of the foam cells have a smaller diameter greater than or equal to the larger diameter of about 70%, about 80%, about 90%, or about 95%.

[0130] In some embodiments, the cross-section of the twisted pair will show compressed and uncompressed regions of the foam insulation layer surrounding the conductor. The compressed region is understood as the portion of the cross-section of the foam insulation layer that deforms during twisting. In some embodiments, the foam cells within the compressed region of the foam insulation layer have a smaller diameter that differs from the larger diameter by approximately 5%, 10%, 15%, or 20%. In some embodiments, the foam cells within the compressed region have an average smaller diameter that is greater than or equal to 70%, 80%, 90%, or 95% of the average larger diameter.

[0131] A cross-section of the foam insulation layer will show multiple foam cells or voids constituting a region of the cross-section. Similarly, multiple polymer regions with calculable combined areas will exist within the cross-section. The ratio of the total foam cell area to the total polymer area can be used to indicate the degree of deformation in a region of the foam polymer cable assembly. In some embodiments, the ratio of foam cell area to polymer area in the compressed region of the foam insulation layer will differ from the ratio in the uncompressed region of the foam insulation layer by approximately 5%, approximately 10%, approximately 15%, or approximately 20%. In some embodiments, the ratio of foam cell area to polymer in the compressed region is greater than or equal to 70%, 80%, 90%, or 95% of the ratio in the uncompressed region.

[0132] In a foam insulation layer, the weight of a cross-sectional slice or a portion thereof can be used to determine or approximate the total air content of that portion of the foam insulation layer (as opposed to the polymer content). In some embodiments, the unit volume weight of the foam insulation material in the compressed region of the foam insulation layer is about 20% greater, 10% greater, or 5% greater than the unit volume weight of the foam insulation material in the uncompressed region of the foam insulation layer. In some embodiments, the unit volume weight of the foam insulation material in the compressed region is less than or equal to 110%, 115%, 120%, 125%, or 130% of the unit volume weight of the foam insulation material in the uncompressed region.

[0133] In some embodiments, the cross-section of the foam insulation layer contains at least 15% by volume air, at least 20% by volume air, at least 25% by volume air, or at least 30% by volume air.

[0134] In some embodiments, the insulating layer comprises a fluoropolymer. In some embodiments, the insulating layer comprises FEP, PFA, PTFE, PVDF, or ETFE. In some embodiments, the insulating layer comprises a fluorinated fluoropolymer having less than about 50 unstable end groups per million carbon atoms. In some embodiments, the insulating layer comprises an unfluorinated fluoropolymer having more than about 50, or more than about 100, or more than about 150, or more than about 200, or more than about 300, or more than about 500 unstable end groups per million carbon atoms. It should be understood that unstable end groups include at least COOH, CF2H, COF, CH2OH, CONH2, and CH2OH.

[0135] In some embodiments, a method for manufacturing a twisted pair is disclosed. In some embodiments, a method includes providing a first foam-insulated conductor and a second foam-insulated conductor, the first foam-insulated conductor comprising a first conductor electrically insulated by a first foam insulation layer, and the second foam-insulated conductor comprising a second conductor electrically insulated by a second foam insulation layer. The first foam insulation layer has a first hardness under environmental conditions. In some embodiments, a method includes hardening the first foam insulation layer to a second hardness greater than the first hardness, and then twisting the first and second foam-insulated conductors together to form a twisted pair while the first foam insulation layer is at the second hardness. In some embodiments, the method includes compressing the first insulation layer while the first foam insulation layer is at the second hardness or exposing the first insulation layer to a compression event.

[0136] In some embodiments, the method further includes hardening the second foam insulation layer from a third ambient hardness to a fourth hardness, which is greater than the third hardness.

[0137] In some embodiments, the step of twisting the first foam insulating conductor and the second foam insulating conductor together occurs within 30 seconds after the first foam insulation layer is hardened to the second hardness, or within 20 seconds after the first foam insulation layer is hardened to the second hardness, or within 10 seconds or 5 seconds.

[0138] In some embodiments, the first foam-insulated conductor and the second foam-insulated conductor are twisted together at a rate greater than 1400 turns per minute (TPM), or greater than 1600 TPM, or greater than 1800 TPM, or greater than 2000 TPM.

[0139] In some embodiments, the step of curing the first foam insulation layer includes cooling the first foam insulation layer. In some embodiments, the insulation layer or other polymer cable assembly may be cured by cooling, crosslinking, radiation, or the use of chemical agents. It should be understood that some of the curing techniques listed herein permanently cure the polymer cable assembly, while others only temporarily cure the polymer cable assembly.

[0140] In some embodiments, the hardening of the first insulation layer is temporary, and the hardness of the first insulation layer returns to a first hardness under environmental conditions. In some embodiments, the first insulation layer returns to a first hardness within 100 seconds of forming the twisted pair, or within 80 seconds of forming the twisted pair, or within 60 seconds of forming the twisted pair, or within 40 seconds of forming the twisted pair, or within 30 seconds of forming the twisted pair, or within 15 seconds of forming the twisted pair, or in the event of the first insulation layer being exposed to a compression event in any other way.

[0141] In some embodiments, a method of manufacturing a communication cable includes providing a first polymer foam cable assembly comprising a polymer foam having foam pores, the first polymer foam cable assembly having a first hardness under environmental conditions; and hardening the first polymer foam cable assembly to a second hardness, the second hardness being greater than the first hardness.

[0142] In some embodiments, the method includes compressing at least a portion of the first polymer foam cable assembly to form a communication cable while the first polymer foam cable assembly is at a second stiffness. In some embodiments, the compression is caused by a metal braid, foil wrapping, strip wrapping, roller, winch, sheath, or other cable assembly. In some embodiments, the polymer foam cable assembly comprises a fluoropolymer. In some embodiments, the polymer foam cable assembly comprises FEP. In some assemblies, the FEP contains more than 50 unstable end groups per million carbon atoms. In some assemblies, the FEP contains more than 80, or more than 100, or more than 150, or more than 200 unstable end groups per million carbon atoms.

[0143] It should be understood that the actions of installing communication cables in a building typically involve dragging, scraping, or otherwise applying compressive force to the polymer cable assembly. In some embodiments, a method of installing communication cables in a building includes providing a first polymer foam cable assembly comprising a polymer foam having foam pores, the first polymer foam cable assembly having a first hardness under environmental conditions; and hardening the first polymer foam cable assembly to a second hardness, the second hardness being greater than the first hardness. In some embodiments, the method further includes positioning at least a portion of the first polymer foam cable assembly at a desired location in the building while the first polymer foam cable assembly is at the second hardness. In some embodiments, the method includes allowing the first polymer foam cable assembly to return to the first hardness.

[0144] In some embodiments, a method of manufacturing a communication cable includes providing a plurality of polymer-insulated conductors, the plurality of polymer-insulated conductors being insulated by polymer foam having a first hardness under environmental conditions; and twisting the plurality of polymer-insulated conductors. The method further includes hardening the polymer foam of a first pair of polymer-insulated conductors to a second hardness, the second hardness being greater than the first hardness; and twisting the first pair of polymer-insulated conductors to form a first twisted pair. In some embodiments, the method includes hardening the polymer foam of a second pair of polymer-insulated conductors to a third hardness, the third hardness being greater than the second hardness; and twisting the second pair of polymer-insulated conductors to form a second twisted pair.

[0145] In some embodiments, the method further includes hardening the polymer foam of the third pair of polymer-insulated conductors to a fourth hardness, the fourth hardness being greater than the third hardness; and twisting the third pair of polymer-insulated conductors to form a third twisted pair.

[0146] In some embodiments, the step of twisting the first pair of polymer-insulated conductors occurs within 30 seconds after the polymer foam of the first pair of polymer-insulated conductors has been hardened to a second hardness, or within 20 seconds, 10 seconds, or 5 seconds after the polymer foam of the first pair of polymer-insulated conductors has been hardened to a second hardness.

[0147] In some embodiments, the cross-section of the polymer foam of the first twisted pair contains at least 15% by volume air. In some embodiments, the cross-section of the polymer foam of the first twisted pair contains at least 10% by volume air, or at least 20% by volume air, or at least 25% by volume air.

[0148] In some embodiments, the pitch of the first twisted pair is longer than that of the second twisted pair. In some embodiments, the pitch of the second twisted pair is longer than that of the third twisted pair. In some embodiments, the pitch of the third twisted pair is longer than that of the fourth twisted pair.

[0149] In some embodiments, the impedance of the first twisted pair differs from that of the second twisted pair by approximately 10 ohms. In some embodiments, the impedance of the first twisted pair differs from that of the second twisted pair by approximately 5 ohms. In some embodiments, the impedance of the first twisted pair differs from that of the second, third, and fourth twisted pairs by approximately 3 ohms, approximately 5 ohms, approximately 10 ohms, or approximately 15 ohms.

[0150] In some embodiments, the method further includes providing a pair of solid polymer-insulated conductors, wherein the polymer-insulated conductors are insulated by a solid polymer, and twisting the pair of solid polymer-insulated conductors together to form a solid twisted pair.

[0151] Some disclosed embodiments relate to a method of manufacturing a communication cable, the method comprising: providing a first pair of insulated conductors, wherein each insulated conductor in the first pair comprises a conductor electrically insulated by a foam polymer layer having a first foam thickness and a solid polymer layer having a first solid thickness, the first pair of conductors having a first outer diameter. The method further comprises providing a second pair of insulated conductors, wherein each insulated conductor in the second pair comprises a conductor electrically insulated by a foam polymer layer having a second foam thickness and a solid polymer layer having a second solid thickness, the second pair of conductors having a second outer diameter. In some embodiments, the method further comprises twisting the first pair of insulated conductors together to form a first twisted pair having a first pitch, and winding the second pair of insulated conductors together to form a second twisted pair having a second pitch. In some embodiments, the ratio of the first foam thickness to the first solid thickness is greater than the ratio of the second foam thickness to the second solid thickness, and the first pitch is shorter than the second pitch.

[0152] In some embodiments, the method further includes curing a polymer foam layer of the first pair of insulating conductors before twisting the first pair of insulating conductors.

[0153] In some embodiments, the first outer diameter and the second outer diameter differ from each other by less than 15%, or by less than 10%, or by less than 5%, or by less than 3%.

[0154] In some implementations, the first twisted pair has a first propagation delay over 100 meters, and the second twisted pair has a second propagation delay over 100 meters, and the first propagation delay and the second propagation delay over 100 meters differ from each other by about 60 nanoseconds, about 50 nanoseconds, about 40 nanoseconds, about 30 nanoseconds, or about 20 nanoseconds.

[0155] In some embodiments, the method further includes providing a third pair of insulated conductors, wherein each insulated conductor of the third pair comprises a conductor electrically insulated by a foam polymer layer having a third foam thickness and a solid polymer layer having a third solid thickness, the conductors of the third pair having a third outer diameter; and providing a fourth pair of insulated conductors, wherein each insulated conductor of the fourth pair comprises a conductor electrically insulated by a foam polymer layer having a fourth foam thickness and a solid polymer layer having a fourth solid thickness, the conductors of the fourth pair having a fourth outer diameter.

[0156] In some embodiments, the method further includes twisting the third pair of insulated conductors together to form a third twisted pair with a third pitch, and twisting the fourth pair of insulated conductors together to form a fourth twisted pair with a fourth pitch. In some embodiments, the ratio of the third foam thickness to the third solid thickness is less than the ratio of the second foam thickness to the second solid thickness, and greater than the ratio of the fourth foam thickness to the fourth solid thickness. In some embodiments, the third pitch is longer than the second pitch and shorter than the fourth pitch. In some embodiments, the first outer diameter, second outer diameter, third outer diameter, and fourth outer diameter differ from each other by less than 25%, or by less than 20%, or by less than 15%, or by less than 10%, or by less than 5%, or by less than 3%.

[0157] In some embodiments, the communication cable comprises a twisted pair of at least one insulated conductor, wherein the insulated conductor comprises a conductor and a polymer insulation layer surrounding the periphery of the conductor, wherein the twisted pair has a twist pitch of less than about 12 mm and a signal propagation delay of less than about 5.2 nanoseconds per meter; and wherein the communication cable passes the NFPA 262 Steiner Tunneling Flame Test. In some embodiments, the cable is a Category 6A cable or is capable of transmitting at least 10 gigabits per second at a frequency of at least 500 MHz.

[0158] In some embodiments, the cable further includes a second twisted pair having a twist pitch of less than about 9 mm and a signal propagation delay of less than about 5.2 nanoseconds / meter. In some embodiments, the insulation layer of the second twisted pair comprises a foamed polymer. In some embodiments, the foamed polymer insulation layer is foamed at least about 10%, about 20%, about 25%, or about 30%.

[0159] In some implementations, the cable has a characteristic impedance between about 85 ohms and 115 ohms, between about 90 ohms and 110 ohms, or between about 95 ohms and 105 ohms at frequencies above 100 mHz.

[0160] In some embodiments, the insulation layer of at least one twisted pair comprises a fluoropolymer, and the insulation layers of different twisted pairs comprise non-fluoropolymers.

[0161] In some embodiments, the communication cable includes a first twisted pair and a second twisted pair with insulated conductors, wherein the insulated conductors include a conductor and a polymer insulation layer surrounding the periphery of the conductor, wherein the first twisted pair has a twist pitch of less than 12 mm and a signal propagation delay of less than 5.2 nanoseconds per meter, and wherein the second twisted pair has a twist pitch shorter than that of the first twisted pair. In some embodiments, the insulation layer of one twisted pair comprises a fluoropolymer, while the insulation layer of the other twisted pair comprises a non-fluoropolymer. In some embodiments, the communication cable passes the NFPA 262 guide tunnel flame test. In some embodiments, the first twisted pair has a twist pitch of less than about 11 mm, about 10 mm, about 9 mm, about 8 mm, or about 7 mm.

[0162] In some embodiments, the communication cable includes at least one twisted pair of insulated conductors located within an outer sheath. The twisted pair comprises two insulating units, each including a conductor and an insulating layer surrounding the periphery of the conductor. The insulating layer comprises a foamed, fluoropolymer with foamed pores. The twisted pair has a twist pitch of less than about 12 mm and a signal propagation delay of less than about 520 nanoseconds per 100 meters. The communication cable passes the NFPA 262 Steiner Tunneling Flame Test.

[0163] In some embodiments, the foam cells have both large and small diameters, and the cross-section of the insulation layer shows that at least 70% of the foam cells have a small diameter greater than or equal to 80% of the large diameter. In some embodiments, at least about 60%, about 75%, about 85%, or about 90% of the foam cells have a small diameter greater than or equal to 90%, 85%, 75%, or 70% of the large diameter.

[0164] In some embodiments, the communication cable includes a first twisted pair, a second twisted pair, a third twisted pair, and a fourth twisted pair with polymer-insulated conductors, wherein the first and second twisted pairs include a foamed polymer insulation layer, and wherein the third and fourth twisted pairs include a solid polymer insulation layer. In some embodiments, the twist pitch of the first and second twisted pairs is shorter than that of the third and fourth twisted pairs, the data transmission rate of the cable is at least 10 gb / s at a frequency of at least 500 MHz, and the length of the cable is at least about 120 m.

[0165] In some embodiments, the cable is at least about 130 m, about 150 m, or about 180 m long. In some embodiments, the cable is a Category 6A cable.

[0166] In some implementations, the pitch of the first twisted pair is less than about 12 mm, about 10 mm, about 8 mm, or about 7 mm.

[0167] In some implementations, lighter, smaller, and / or more useful cables can be produced by increasing the stiffness of the polymer cable assembly before or during manufacturing. If the cable assembly is not compressed or otherwise deformed, less total insulation material may be required to achieve the same electrical performance. The total thickness of the insulation can be reduced if the insulation is less compressed during manufacturing due to stress / strain response and increased stiffness.

[0168] The methods, systems, and implementations described herein generally involve modulating the stress / strain response and stiffness of polymer components. Polymers considered herein include, but are not limited to, thermoplastics, thermosetting plastics, rubbers, and / or elastomers, each of which may be foamed or solid and may contain various additives and / or flame retardants. Specific polymers considered include, but are not limited to: linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), polyethylene (PE), perfluoroalkoxyalkylene (PFA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), ethylene chloride trifluoroethylene (ECTFE), tetrafluoroethylene, perfluoromethyl vinyl ether (MFA), polyphenylene sulfide (PPS), polyetherketone (PEEK), polyetherketone (PEK), polyethyleneimine (PEI), fluorinated ethylene propylene (FEP), and ethylene propylene tetrafluoroethylene (E). TFE, ethylene fluoride propylene-EFEP, polypropylene-PP, nylon-PA, polyvinyl chloride-PVC, polycarbonate-PC, acrylonitrile butadiene styrene-ABS, polystyrene-PS, polyesters such as polyethylene terephthalate (PET), polyimide-PI, polyamide, polyimide, polyamide-imide-PAI, natural rubber, synthetic rubber, fluorinated elastomers-FKM, silicones (such as dimethyl polysiloxane), PVdF, PEBA, their foams, their blends and alloys.

[0169] Those skilled in the art will recognize improvements and modifications to the preferred embodiments of this disclosure. All such improvements and modifications are considered to be within the scope of the concepts disclosed herein and the appended claims. It is to be understood that any given element of the disclosed embodiments of the invention may be embodied as a single structure, a single step, a single substance, etc. Similarly, a given element of the disclosed embodiments may be embodied as multiple structures, steps, substances, etc.

[0170] The foregoing description and accompanying drawings illustrate and describe certain processes, machines, articles, and material compositions, some of which embody the invention. Such description or illustration is not intended to limit the scope of the claims, but is set forth to aid in understanding the claims, in implementing and using the claims, and in teaching the best mode of using the invention. If this description and accompanying drawings are interpreted as disclosing only one particular embodiment or several embodiments, they should not be construed as limiting the scope of the claims to that particular embodiment or several embodiments. Any example or embodiment of the invention described herein is not intended to suggest that the scope of the claims must be identical to that example or embodiment. When references are made to the invention or embodiments thereof achieving one or more objectives, it is not intended to limit the scope of the claims to solutions capable of achieving all of those objectives. Any statement in this specification criticizing the prior art is not intended to limit the scope of the claims to exclude any aspect of the prior art.

[0171] In addition, this disclosure shows and describes certain embodiments of the disclosed processes, machines, manufacturing, material composition, and other teachings, but it is to be understood that the teachings of this disclosure can be used in various other combinations, modifications, and environments, and can be changed or modified within the scope of the teachings expressed herein.

[0172] Any section headings provided herein are provided solely for the purpose of conforming to the recommendations of 37 CFR § 1.77 or otherwise providing an organizational framework. These headings should not limit or characterize the inventions set forth herein.

Claims

1. A communication cable, the communication cable comprising: At least one twisted pair of insulated conductors, wherein the insulated conductors comprise conductors and an insulating layer surrounding the periphery of the conductors, and wherein the insulating layer comprises a foamed polymer having foam pores having a large diameter and a small diameter, and wherein a cross-section of the insulating layer shows that at least 50% of the foam pores have a small diameter greater than or equal to 80% of the large diameter.

2. The communication cable according to claim 1, wherein, At least one insulation layer of the twisted pair includes a compressed region and an uncompressed region, wherein at least 50% of the foam cells in the compressed region have an average small diameter greater than or equal to 80% of the average large diameter.

3. The communication cable according to claim 1, wherein, At least one insulation layer of the twisted pair includes a compressed region and an uncompressed region, wherein the ratio of the foam cells to the polymer in the compressed region is greater than or equal to 90% of the ratio of the foam cells to the polymer in the uncompressed region.

4. The communication cable according to claim 1, wherein, At least one insulation layer of the twisted pair includes a compressed region and an uncompressed region, wherein the volumetric weight of the foam insulation material in the compressed region is less than or equal to 125% of the volumetric weight of the foam insulation material in the uncompressed region.

5. The communication cable according to claim 1, wherein, The insulating layer comprises a fluoropolymer.

6. The communication cable according to claim 1, wherein, The insulating layer includes FEP.

7. The communication cable according to claim 1, wherein, The insulating layer comprises a fluoropolymer foam having at least 100 unstable end groups / million carbon atoms.

8. The communication cable according to claim 1, wherein, The insulating layer comprises a fluoropolymer foam having at least 200 unstable end groups / million carbon atoms.

9. The communication cable according to claim 1, wherein, The insulating layer contains at least 15% by volume air.

10. A method for manufacturing a twisted pair cable, the method comprising the following steps: A first foam-insulated conductor and a second foam-insulated conductor are provided, the first foam-insulated conductor comprising a first conductor electrically insulated by a first foam insulation layer, and the second foam-insulated conductor comprising a second conductor electrically insulated by a second foam insulation layer; the first foam insulation layer has a first hardness under environmental conditions. The first foam insulation layer is hardened to a second hardness, where the second hardness is greater than the first hardness; While the first foam insulation layer is at the second hardness, the first foam insulation conductor and the second foam insulation conductor are twisted together to form a twisted pair.

11. The method according to claim 10, wherein, The second foam insulation layer has a third hardness, and the method further includes hardening the second foam insulation layer to a fourth hardness, the fourth hardness being greater than the third hardness.

12. The method according to claim 10, wherein, The step of twisting the first foam insulating conductor and the second foam insulating conductor around each other occurs within 10 seconds after the first foam insulation layer is hardened to the second hardness.

13. The method according to claim 10, wherein, The first foam-insulated conductor and the second foam-insulated conductor are twisted together around each other at a speed greater than 2000 revolutions per minute (TPM).

14. The method of claim 10, wherein, The step of hardening the first foam insulation layer includes cooling the first foam insulation layer.

15. A method for manufacturing a communication cable, the method comprising the following steps: A first polymer foam cable assembly is provided, the polymer foam cable assembly comprising a polymer foam having foam cells, the first polymer foam cable assembly having a first hardness under environmental conditions; The first polymer foam cable assembly is hardened to a second hardness, wherein the second hardness is greater than the first hardness; While the first polymer foam cable is at the second stiffness, at least a portion of the first polymer foam cable assembly is compressed to form a communication cable.

16. The method according to claim 15, wherein, The first polymer foam cable assembly comprises a fluoropolymer.

17. The method according to claim 15, wherein, The first polymer foam cable assembly includes FEP.

18. The method according to claim 15, wherein, The first polymer foam cable assembly includes an FEP having more than 80 unstable end groups / million carbon atoms.

19. The method according to claim 15, wherein, The composition of the first polymer foam cable assembly is not changed during the step of hardening the first polymer foam cable assembly to the second hardness.

20. The method of claim 15, further comprising: The first polymer foam cable assembly is returned to the first hardness step.

21. A method for installing communication cables in a building, the method comprising the following steps: A first polymer foam cable assembly is provided, the polymer foam cable assembly comprising a polymer foam having foam cells, the first polymer foam cable assembly having a first hardness under environmental conditions; The first polymer foam cable assembly is hardened to a second hardness, where the second hardness is greater than the first hardness; While the first polymer foam cable assembly is at the second stiffness, at least a portion of the first polymer foam cable assembly is positioned at the desired location on the building.

22. A method for manufacturing a communication cable, the method comprising the following steps: A plurality of polymer-insulated conductors are provided, wherein the polymer-insulated conductors are insulated by polymer foam having a first hardness under environmental conditions; The plurality of polymer-insulated conductors are divided into pairs; The polymer foam of the first pair of polymer insulating conductors is hardened to a second hardness, which is greater than the first hardness; The first pair of polymer-insulated conductors are twisted together around each other to form a first twisted pair; The polymer foam of the second pair of polymer insulating conductors is hardened to a third hardness, the third hardness being greater than the second hardness; and The second pair of polymer-insulated conductors are twisted together to form a second twisted pair.

23. The method according to claim 22, further comprising: The polymer foam of the third pair of polymer insulating conductors is hardened to a fourth hardness, which is greater than the third hardness; And the third pair of polymer-insulated conductors are twisted together to form a third twisted pair.

24. The method according to claim 22, wherein, The polymer foam includes fluoropolymers.

25. The method according to claim 22, wherein, The step of twisting the first pair of polymer-insulated conductors together occurs within 10 seconds after the polymer foam of the first pair of polymer-insulated conductors is hardened to a second hardness.

26. The method according to claim 22, wherein, The polymer foam of the first twisted pair contains at least 15% by volume air.

27. The method according to claim 22, wherein, The twist pitch of the first twisted pair is longer than that of the second twisted pair.

28. The method of claim 22, further comprising the step of: A third pair of solid polymer insulated conductors is provided, and the third pair of solid polymer insulated conductors are twisted together to form a third twisted pair.

29. The method according to claim 22, wherein, The impedance value of the first twisted pair differs from that of the second twisted pair by less than 10 ohms.

30. A method for manufacturing a communication cable, the method comprising the following steps: A first pair of insulated conductors is provided, wherein each insulated conductor in the first pair of insulated conductors comprises a conductor electrically insulated by a polymer foam layer having a first foam thickness and a solid polymer layer having a first solid thickness, and the conductors of the first pair have a first outer diameter; A second pair of insulated conductors is provided, wherein each insulated conductor in the second pair of insulated conductors comprises a conductor electrically insulated by a polymer foam layer having a second foam thickness and a solid polymer layer having a second solid thickness, and the conductors of the second pair have a second outer diameter; The first pair of insulated conductors are twisted together to form a first twisted pair with a first pitch. The second pair of insulated conductors are twisted together around each other to form a second twisted pair with a second pitch. Wherein, the ratio of the first foam thickness to the first solid thickness is greater than the ratio of the second foam thickness to the second solid thickness, and wherein, the first pitch is shorter than the second pitch.

31. The method according to claim 30, wherein, The difference between the first outer diameter and the second outer diameter is within 10%.

32. The method according to claim 30, further comprising: Before stranding the first pair of insulated conductors, the polymer foam layer of the first pair of insulated conductors is hardened.

33. The method according to claim 30, wherein, The first twisted pair has a first propagation delay over a length of 100 meters, and the second twisted pair has a second propagation delay over a length of 100 meters, and the first propagation delay and the second propagation delay over a length of 100 meters differ from each other by less than 50 nanoseconds.

34. The method according to claim 30, further comprising: A third pair of insulated conductors is provided, wherein each insulated conductor in the third pair comprises a conductor electrically insulated by a polymer foam layer having a third foam thickness and a solid polymer layer having a third solid thickness, the conductors of the third pair having a third outer diameter; A fourth pair of insulated conductors is provided, wherein each insulated conductor in the fourth pair comprises a conductor electrically insulated by a polymer foam layer having a fourth foam thickness and a solid polymer layer having a fourth solid thickness, the conductors of the fourth pair having a fourth outer diameter; The third pair of insulated conductors are twisted together to form a third twisted pair with a third pitch; The fourth pair of insulated conductors are twisted together to form a fourth twisted pair with a fourth pitch; Wherein, the ratio of the third foam thickness to the third solid thickness is less than the ratio of the second foam thickness to the second solid thickness and greater than the ratio of the fourth foam thickness to the fourth solid thickness, and wherein the third pitch is longer than the second pitch and shorter than the fourth pitch, and wherein the first outer diameter, the second outer diameter, the third outer diameter and the fourth outer diameter differ from each other by less than 15%.

35. A communication cable, the communication cable comprising: At least one twisted pair of insulated conductors, wherein the insulated conductors comprise a conductor and a polymer insulation layer surrounding the periphery of the conductor; The twisted pair cable has a twist pitch of less than approximately 12 mm and a signal propagation delay of less than approximately 5.2 nanoseconds per meter; and The communication cable passed the NFPA 262 Steiner Tunnel Flame Test.

36. The communication cable according to claim 35, wherein, The cable is a Category 6A cable.

37. The communication cable according to claim 35, further comprising a second twisted pair, wherein, The second twisted pair has a twist pitch of less than about 9 mm and a signal propagation delay of less than about 5.2 nanoseconds per meter.

38. The communication cable according to claim 37, wherein, The insulation layer of the second twisted pair comprises a foamed polymer.

39. The communication cable according to claim 38, wherein, The foamed polymer insulation layer is foamed at least 25%.

40. The communication cable according to claim 37, wherein, The insulation layer of at least one twisted pair comprises a fluoropolymer, and wherein the insulation layer of different twisted pairs comprises a non-fluoropolymer.

41. The communication cable according to claim 35, wherein, At frequencies of 100 MHz or higher, the cable has a characteristic impedance between approximately 85 ohms and 115 ohms.

42. A communication cable, the communication cable comprising: A first twisted pair and a second twisted pair of insulated conductors, wherein the insulated conductors comprise a conductor and a polymer insulating layer surrounding the periphery of the conductor, wherein the first twisted pair has a twist pitch of less than 12 mm and a signal propagation delay of less than 5.2 nanoseconds per meter, and wherein the second twisted pair has a twist pitch shorter than that of the first twisted pair. Wherein, the insulation layer of one twisted pair of the twisted pair comprises a fluoropolymer, and wherein the insulation layer of the other twisted pair comprises a non-fluoropolymer; and The communication cable passed the NFPA 262 Steiner Tunnel Flame Test.

43. A communication cable, the communication cable comprising: At least one twisted pair with an insulated conductor positioned within an outer sheath, wherein the twisted pair comprises two insulating units, each insulating unit comprising a conductor and an insulating layer surrounding the periphery of the conductor, and wherein the insulating layer comprises a foamed fluoropolymer having foam pores. The twisted pair has a twist pitch of less than approximately 12 mm; The twisted pair cable has a signal propagation delay of less than approximately 520 nanoseconds per 100 meters; and The communication cable passed the NFPA 262 Steiner Tunnel Flame Test.

44. The communication cable according to claim 43, wherein, The foam cells have large and small diameters, and wherein a cross-section of the insulating layer shows that at least 70% of the foam cells have a small diameter that is greater than or equal to 80% of the large diameter.

45. A communication cable, the communication cable comprising a first twisted pair, a second twisted pair, a third twisted pair, and a fourth twisted pair with polymer-insulated conductors, wherein, The first twisted pair and the second twisted pair include a foam polymer insulation layer, and wherein the third twisted pair and the fourth twisted pair include a solid polymer insulation layer; Wherein, the twist pitch of the first twisted pair and the second twisted pair is shorter than the twist pitch of the third twisted pair and the fourth twisted pair; Wherein, at a frequency of at least 500 MHz, the data transmission rate of the cable is at least 10 gb / s; and The cable is at least 120 m long.

46. ​​The communication cable according to claim 45, wherein, The length of the cable is at least 150 m.

47. The communication cable according to claim 45, wherein, The cable is a Category 6A cable.

48. The communication cable according to claim 45, wherein, The twist pitch of the first twisted pair is less than about 8 mm.

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