Semiconductive tape and its manufacturing method

Abstract

A semiconductive tape for use on electrical cables, such as high-voltage power cables, and a method for manufacturing such a tape are provided. The semiconductive tape includes a first layer including a fabric and a second layer in contact with the first layer. The second layer includes activated carbon or carbon black. The semiconductive tape has increased friction while still maintaining sufficient conductivity for use as a wrap on electrical cables, thereby improving the manufacturing process and reducing the overall cost of production.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 417,772, filed October 20, 2022, the entire disclosure of which is incorporated herein by reference for all purposes.

[0002] The present invention relates generally to semi-conductive tapes, and more particularly to semi-conductive tapes for use with electrical cables, such as overhead, underwater or underground power cables. [Background technology]

[0003] High-voltage power cables are used to transmit electricity at medium or high voltage. The cables typically comprise a conductor and a polymeric insulation system surrounding the conductor. Power cables that can be buried underground are called terrestrial cables. Power cables that can be buried on the seabed and extend freely between two fixed points in the water are called submarine, subsea, or underwater power cables. Underwater power cables are currently being used in increasing numbers due to the growing need to transmit power from offshore energy sources, including offshore renewable energy plants such as wind farms. The length of power transmission cables is also increasing due to the need to interconnect transmission networks between different regions to enable global energy trade. The need for safe power transmission is further heightened by the fact that energy-demanding regions on the one hand and energy-producing regions on the other may be far apart. Semiconductive cable tapes are used in a number of bedding, binding, separation, splicing, and identification applications in heavy-duty power cables, multi-core cables, and communication cables. Semiconductive cable tapes offer numerous physical and electrical properties for a wide variety of cable manufacturing applications. Semiconductive cable tapes are typically made from a substrate of either nylon, polyester, or woven PET fabric coated on one or both sides with a cross-linked acrylic semiconductive compound. These tapes equalize field currents around the power conductor or core, ensuring contact with the grounding system. This reduces electrical stress on the insulating material and enhances performance. The tapes can also be used to prevent galvanic corrosion of the metallic armor layer of high-voltage cables. While these semiconductive cable tapes have proven useful, they also suffer from drawbacks. For example, the acrylic semiconductive compounds commonly used in such tapes generally have a relatively low coefficient of friction, making them slippery, especially during the cable manufacturing process. This can create manufacturing challenges and increase the overall cost of cable production. High-friction tapes, such as cloth adhesive tape or PVC electrical tape, have a higher coefficient of friction than standard semi-conductive cable tapes, but these types of tapes are generally not conductive enough to be used as wrapping for power cables. Therefore, there is a need for a semi-conductive cable tape that has increased friction to improve the manufacturing process, yet still maintains sufficient conductivity for use in power cables. Summary of the Invention

[0004] The following presents a simplified summary of the claimed subject matter in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview of the claimed subject matter, and is not intended to identify key or critical elements of the claimed subject matter or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts of the claimed subject matter as a prelude to the more detailed description that is presented later.

[0005] Semiconductive tapes and methods for manufacturing such tapes are provided. Semiconductive tapes are also provided for use in seating, wrapping, separation, splicing, and / or identification applications in heavy-duty power cables, multi-core cables, and communication cables. The semiconductive tapes have increased friction while still maintaining sufficient conductivity for use as wraps for electrical cables, such as high- or medium-voltage overhead, underwater, and / or underground power cables used to transmit electrical power at medium or high voltages. This improves the cable manufacturing process and reduces overall manufacturing costs. In one embodiment, a semiconductive tape includes a first layer including a fabric and a second layer in contact with the first layer. The second layer includes activated carbon or carbon black. Applicant has discovered that the activated carbon and / or carbon black increases the static and dynamic coefficients of friction of the tape while maintaining sufficient electrical conductivity for use, for example, as a wrap for high voltage electrical cables. In various embodiments, the tape further comprises a third layer comprising activated carbon or carbon black. The second and third layers are preferably bonded to opposite sides of the first layer. In various embodiments, the second and / or third layers comprise a fluid such as water, and the solids content of the second layer is about 30% to about 60%, preferably about 45%. Applicants have discovered that solids content greater than about 60% results in an unstable mixture, while solids content less than about 30% reduces the conductivity of the layers such that the overall tape is not sufficiently conductive to function as a cable wrap. In various embodiments, the second and / or third layer includes carbon black. The carbon black may be substantially or completely solid and may include mixed pigments or substantially the same pigment. The carbon black may be hydrophobic. Hydrophobic carbon black can be transported alone, i.e., without mixing with an aqueous solution such as water. This increases the solids content of the final mixture used to produce the second and / or third layer. In various embodiments, the carbon black is about 6% to about 35% by weight of the second and / or third layer, preferably about 24.5% by weight of the second layer. Applicants have discovered that mixtures with more than about 35% by weight carbon black result in unstable mixtures, while mixtures with less than about 6% carbon black reduce the conductivity of the layers such that the overall tape is not sufficiently conductive to function as a cable wrap. The second and / or third layer may further comprise an electrically insulating polymer, such as an acrylic copolymer dispersed in water, which may be self-crosslinking and may function to bond the second and / or third layer to the first layer.

[0006] Suitable materials for the fabric include, but are not limited to, nylon, polyester, synthetic fibers, natural fibers, and synthetic polymers. In certain embodiments, the fabric comprises nylon or polyester, or a combination thereof. The second and / or third layer may further comprise about 25% to about 30% by weight of water. The second and / or third layer may comprise a dispersing agent such as sodium polyacrylate. The second and / or third layer may further comprise a suspending agent such as a polysaccharide. The second and / or third layer may comprise an antifoaming agent such as mineral oil. The second and / or third layer may comprise a thickener such as NaOH and other stabilizers. The second and / or third layers may further comprise a second polymer, which may be similar to or substantially different from the first polymer. Suitable materials for the second polymer include acrylate-styrene copolymers.

[0007] In certain embodiments, the tape has substantially the same or greater friction than conventional protective non-conductive tapes. In one such embodiment, the tape has a static coefficient of friction of at least about 1.00, preferably at least about 1.25, and more preferably about 1.4 to 2.0. The tape may have a kinetic or dynamic coefficient of friction of at least about 0.7, preferably at least about 0.8.

[0008] In embodiments, the tape has sufficient conductivity to function as a wrap for a cable, such as a high voltage cable. In one such embodiment, the tape is configured to overlie the core conductor of the cable. In another embodiment, the tape is configured to overlie the outer wrap of the cable. In other embodiments, the tape may be disposed around one of the other layers of the cable, such as the inner semiconductive layer, the insulation, the outer semiconductive layer, the shield, the seat and backing layer, or the outer sheath (armor) of the cable. The tape preferably has a volume resistivity of about 1 million Ω / cm or less, more preferably about 100 Ω / cm or less. The tape also preferably has a total resistance (Through / Res)≦500 Ω and a surface resistance (Surface / Res)≦10,000 Ω / sq.

[0009] In another aspect, an electrical cable is provided that includes a wrapping tape. The cable may include a high-voltage or medium-voltage power cable. The cable may be configured for use as an overhead, underwater, and / or underground power cable. The wrapping tape includes a first layer of fabric and a second layer that includes activated carbon or carbon black. In another aspect, a method for making a semiconductive tape includes providing a first layer of fabric and a second layer comprising activated carbon or carbon black, the second layer being bonded to a surface of the first layer to increase friction and form a semiconductive tape having sufficient conductivity for use as a cable wrap for electrical cables. In an embodiment, the second layer is formed from a mixture of activated carbon or carbon black and a polymer, which mixture is then applied to the surface of the first layer. The polymer preferably includes a material that promotes bonding of the activated carbon or carbon black to the first layer. The second layer preferably has a moisture content sufficient to allow it to be applied to the first layer as a substantially fluid mixture. The first layer may be stretched over a device such as a frame, winder, or roll to provide a substantially flat or level surface for application of the second layer. In embodiments, the first and second layers are dried to remove moisture and / or to promote bonding of the second layer to the first layer. The second layer may further comprise a polymer, such as an acrylic copolymer, dispersed in water. The method may further comprise crosslinking the acrylic copolymer to bond the second layer to the first layer. In an embodiment, the method further includes forming a third layer comprising activated carbon or carbon black and bonding the third layer to the first layer. The second and third layers may be bonded to opposite sides of the first layer.

[0010] Reference herein to desirable objects achieved by various embodiments of the present description is not meant to imply or suggest that any or all of these objects, individually or collectively, are present as essential features in either the most general embodiment of the description or in any of the more specific embodiments. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a table comparing the static coefficient of friction of tapes described herein with prior art tapes. [Figure 2] 1 is a table comparing the dynamic coefficient of friction of tapes described herein with prior art tapes. DETAILED DESCRIPTION OF THE INVENTION

[0012] This description and the accompanying drawings illustrate illustrative embodiments and should not be taken as limiting; the claims, including equivalents, define the scope of this description. Various mechanical, compositional, structural, and operational changes, including equivalents, may be made without departing from the scope of this description and claims. In some instances, well-known structures and techniques have not been shown or described in detail to avoid obscuring the description. Like numbers in two or more drawings represent the same or similar elements. Furthermore, elements and related aspects described in detail with reference to one embodiment may, whenever practical, be included in other embodiments not specifically shown or described. For example, even if an element is described in detail with reference to one embodiment and not with reference to a second embodiment, the element may still be claimed to be included in the second embodiment. Furthermore, the depictions herein are for illustrative purposes only and do not necessarily reflect the actual shape, size, or dimensions of the system or illustrated components. As used in this specification and the appended claims, please note that the singular forms "a," "an," and "the," as well as the use of any singular form of any word, include plural references unless expressly and unambiguously limited to one reference. As used herein, the term "comprises" and its grammatical variations are intended to be open-ended, and the recitation of items in a list does not exclude other similar items that may be substituted for or added to the items in the list. Unless otherwise specified, any quantitative value is approximate, whether or not indicated by words such as "about" or "approximately." The materials, methods, and examples described herein are illustrative only and are not intended to be limiting.

[0013] Semiconductive tapes and methods for manufacturing such tapes are provided. Semiconductive tapes for use with power cables, such as overhead, underwater, or underground power cables, are also provided. The semiconductive tapes have increased friction while still maintaining sufficient conductivity for use as wraps for electrical cables, thereby improving the manufacturing process and reducing the overall cost of manufacturing. In various embodiments, the semiconductive tapes described herein include a fabric and an activated carbon or carbon black material. The fabric may be mixed with the carbon material to form a single layer. Alternatively, the tape may be formed as separate layers bonded together. In one embodiment, the tape includes a first fabric layer bonded to a second layer containing activated carbon or carbon black. The fabric may comprise any material suitable for use with tape, such as semi-conductive tape. Suitable fabrics include, but are not limited to, nylon, polyester, synthetic fibers, natural fibers, and synthetic polymers. In certain embodiments, the fabric comprises nylon or polyester, or a combination thereof.

[0014] In certain embodiments, the tape further comprises a third layer comprising activated carbon or carbon black. The second and third layers are preferably bonded to opposite sides of the first layer. The second and / or third layer may comprise carbon black or activated carbon, such as powdered activated carbon, crushed activated carbon, granulated activated carbon, activated carbon cloth, wood-based activated carbon, etc. Suitable carbon blacks include acetylene black, channel black, furnace black, lamp black, thermal black, or combinations thereof. The carbon black may contain mixed pigments or may contain substantially the same pigment. Activated carbon or charcoal filters are made from organic materials that are substantially high in carbon content. Heat may be used to increase the surface area or activate the carbon in the absence of oxygen. Suitable activated carbon materials include bamboo, coconut shells, willow peat, wood, coir, lignite, coal, petroleum, soybean husks, nut shells, sugarcane bagasse, and combinations thereof. In certain embodiments, carbon black is substantially hydrophobic, so that it can be transported alone, i.e., without mixing with an aqueous solution such as water, which increases the solids content of the final mixture used to make the second layer. In one embodiment, the carbon black is 100% solids and preferably comprises from about 6% to about 35% by weight of the second layer, preferably about 24.5% by weight of the second layer.

[0015] The second and / or third layer may further comprise a polymer that promotes bonding to the first layer. Suitable polymers for the second layer include acrylic copolymers, such as sodium polyacrylate, polyvinyl acetate, polyacrylamides, latex, and combinations thereof. The copolymer may be a stable emulsion or dispersion of polymeric microparticles in an aqueous solution. In certain embodiments, the polymer is self-crosslinking and "sets" when dried and the aqueous solution (e.g., water) is substantially removed from the mixture. This sets promotes bonding between the carbon black and the first layer. The polymer is about 40% to about 50% solids, preferably about 45% solids, and comprises about 35% to about 50%, preferably about 40.9%, by weight of the total mixture. The second and / or third layer may also include a second polymer, which also promotes bonding to the first layer. The second polymer may be a similar material to the first polymer, or may be a substantially different material. Suitable second polymers for the second layer include acrylic copolymers, such as sodium polyacrylate, polyvinyl acetate, polyacrylamides, acrylate-styrene, latex, and combinations thereof. The copolymer may be a stable emulsion or dispersion of polymeric particles in an aqueous solution. The second polymer is about 40% to about 60% solids, preferably about 50% solids, and constitutes about 2% to about 5%, preferably about 3.4%, by weight of the total mixture.

[0016] The second and / or third layers may further comprise a dispersing agent to facilitate dissolution of the surfactant and additives into the mixture. Suitable dispersing agents include polyvinylpyrrolidone (PVP), sodium hexametaphosphate (SHP), sodium salt of EDTA, sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), sodium polyacrylate, and the like. In one embodiment, the dispersing agent comprises sodium polyacrylate manufactured by Coatex, known under the trade name RHEOSOLVE. The dispersing agent is about 40% to about 60% solids, preferably about 45% solids, and comprises about 0.1% to about 0.5%, preferably about 0.4%, by weight of the total mixture. The second and / or third layer may further comprise a suspending agent to promote particle suspension or dispersion and reduce settling. Suitable suspending agents include aqueous biopolymers such as methylcellulose (MC), sodium carboxymethylcellulose (CMC), hydroxypropylmethylcellulose (HPMC), polysaccharides, and the like. In one embodiment, the dispersing agent comprises a polysaccharide available from TER Chemicals under the trade name Xanthan Gum. The suspending agent is preferably 100% solids and comprises from about 0.5% to about 2%, preferably about 1%, by weight of the total mixture. The second and / or third layers may further comprise an antifoaming agent to reduce the surface tension of the mixture. Suitable antifoaming agents include certain alcohol (e.g., cetostearyl alcohol) aqueous solutions, insoluble oils (e.g., castor oil), stearates, polydimethylsiloxane and other silicone derivatives, ethers, glycols, mineral oil, and the like. In one embodiment, the antifoaming agent comprises mineral oil, available from Blackburn Chemicals under the trade name DISPELAIR. The antifoaming agent is preferably from about 1% to about 100% solids and constitutes from about 0.05% to about 0.22%, preferably about 0.1%, by weight of the total mixture. The second and / or third layers may further comprise a thickener to increase the overall viscosity of the mixture. Suitable thickeners include starch, gelatin, acacia, pectin, agar, NaOH, stabilizers, etc. The thickener is about 10% to about 20% solids, preferably about 17% solids, and comprises about 0.5% to about 1%, preferably about 0.8%, by weight of the total mixture. The second and / or third layer may further comprise an aqueous solution, such as water, to reduce the total solids content of the second layer. In one embodiment, water comprises about 20% to about 40% by weight of the total mixture, preferably about 25% to 30% by weight, and more preferably about 28.9% by weight. The second and / or third layers may also contain other materials such as antifoaming agents, bactericides, fungicides, metal sequestering agents, and the like.

[0017] The total solids content of the second and / or third layers is preferably about 30% to about 60%, preferably about 45%. Applicants have discovered that solids content greater than about 60% results in an unstable mixture, while solids content less than about 30% reduces the conductivity of the layers such that the overall tape is not sufficiently conductive to function as a cable wrap. The tape preferably has sufficient conductivity for use as a cable wrap. The tape preferably has a volume resistivity of about 1 million ohms / cm, more preferably about 100 ohms / cm or less. The tape also preferably has a total resistivity of ≦500 ohms and a surface resistivity of ≦10,000 ohms / sq. The tape may be placed over the conductors of the cable, or the tape may be placed over one of the other layers of the cable, such as the inner semiconductive layer, the insulation, the outer semiconductive layer, the shield, the seat and backing layer, or the outer sheath of the cable. In one embodiment, the tape is placed over the outer wrap of the cable, just below the final plastic sheath component. [Example]

[0018] Applicant tested the friction of a tape having two layers of the above mixture adhered to a fabric ("high friction semiconductive tape or HFS tape"). The two layers were bonded to opposite sides of the fabric. Applicant compared the results of this test with two conventional tapes: (1) a conventional protective tape known under the trade name CT50 / 113 and sold by Scapa UK Ltd; and (2) a conventional semiconductive tape known under the trade name SC36 / 65 and sold by Scapa UK Ltd. Applicant performed tests on 11 different samples of SC36 / 65 tape, 5 different samples of CT50 / 113 protective tape, and 8 different samples of the tape described herein. Each sample was prepared by cutting the sample to the appropriate size, placing it on a test stand, and ensuring that the sample was as smooth as possible (i.e., by attaching clips or tape to both sides of the sample). Each sample was tested for friction using a Testometric machine, a friction device (i.e., a sled, a weight, and a cable), and a 2 kgf load cell. The sled was pulled along the test stand at a rate of approximately 100 mm / min, and the friction was recorded on the Testometric machine.

[0019] As shown in Figure 1, the HFS tape described herein had a higher static coefficient of friction than the two conventional tapes. The HFS tape had an average static coefficient of friction of 1.442, while the conventional protective tape had an average static coefficient of friction of only 1.087 and the conventional semiconductive tape had an average static coefficient of friction of 0.46. Furthermore, the HFS tape had substantially the same conductive properties as the semiconductive tape. As shown in Figure 2, the HFS tapes described herein had a higher dynamic friction coefficient than the conventional tapes. The HFS tapes had an average dynamic friction coefficient of 0.8294, while the protective tapes had an average static friction coefficient of only 0.7844 and the semiconductive tapes had an average static friction coefficient of only 0.3685. Thus, the HFS tapes described herein have substantially the same conductive properties as conventional semiconductive tapes, but have higher friction than both the protective tape and the semiconductive tape.

[0020] The semiconducting tapes described herein are manufactured by forming a first layer comprising a fabric and a second layer comprising activated carbon or carbon black, which is bonded to the first layer to form a semiconducting tape. The second layer is formed from a mixture of activated carbon or carbon black and at least one polymer, which mixture is then applied to the surface of the first layer. The mixture preferably contains the above ingredients at a total solids content of about 30% to about 60%, preferably about 45%. The second layer preferably has a moisture content sufficient to allow it to be applied to the first layer as a substantially liquid layer. The first layer may be stretched over a device such as a frame, winder, or roller to provide a flat or smooth surface for application of the second layer. The first and second layers are dried to remove moisture and / or to promote bonding of the second layer to the first layer. The method may further include crosslinking the acrylic copolymer to bond the second layer to the first layer.

[0021] In an exemplary embodiment, the fabric layer is stretched over a frame so that the edges are held. The frame may include a tenter or similar apparatus. The fluid carbon black mixture is applied to the fabric through a conduit, such as a pipe, tube, or nozzle, positioned to deliver the fluid mixture directly onto the fabric on the tenter. The mixture is then smoothed or leveled with a blade or other suitable leveling device until it is substantially flat (e.g., similar to screen printing). The thickness and mass of the mixture depend on the specific application of the tape. The fabric layer and mixture are then passed through a series of drying devices, such as ovens, to remove substantially all of the water from the mixture and solidify the mixture. The mixture is preferably solidified by crosslinking the polymers within the mixture under heat, which causes the mixture to bond to the fabric layer. In certain embodiments, the mixture is cured at about 150 degrees Celsius, although the exact temperature will depend on the specific self-crosslinking polymer used in the mixture. In embodiments, the tape is then unwound and returned to the tenter with the opposite side facing the pipe or conduit. A carbon black-based mixture is then applied to the opposite side in the same manner as described above. This second layer of mixture is then dried and passed through an oven to bond to the fabric layer, forming a tape with the first and second layers of mixture on opposite sides of the fabric. Alternatively, the fabric may be immersed in a liquid bath of the mixture to coat both sides of the fabric simultaneously. In this embodiment, the mixture-coated fabric is then forced through two rolls or similar device to smooth or flatten the mixture before drying and curing.

[0022] While the devices, systems, and methods have been described in detail herein in accordance with certain preferred embodiments thereof, numerous modifications and variations may be implemented by those skilled in the art. Accordingly, the above description should not be construed as limited thereby, but should be construed to include such obvious variations as may be apparent, and should be limited only by the spirit and scope of the following claims.

[0023] For example, in a first aspect, a first embodiment is a semiconductive tape comprising a first layer comprising a fabric and a second layer in contact with the first layer, the second layer comprising a polymer and activated carbon or carbon black. A second embodiment is the first embodiment, wherein the second layer comprises carbon black. A third embodiment is any combination of the first and second embodiments, wherein the polymer comprises an electrically insulating material. A fourth embodiment is any combination of the first through third embodiments, wherein the polymer comprises an acrylic copolymer dispersed in water. A fifth embodiment is any combination of the first to fourth embodiments, wherein the carbon black is hydrophobic. A sixth embodiment is any combination of the first through fifth embodiments, further comprising a third layer comprising a polymer and activated carbon or carbon black, and the first layer is disposed between the second and third layers. A seventh embodiment is any combination of the first to sixth embodiments, wherein the fabric comprises a material selected from the group consisting of nylon, polyester, synthetic fibers, natural fibers, and synthetic polymers. An eighth embodiment is any combination of the first to seventh embodiments, wherein the solids content of the second layer is about 30% to about 60%. A ninth embodiment is any combination of the first through eighth embodiments, with a solids content of about 45%. A tenth embodiment is any combination of the first to ninth embodiments, wherein the carbon black is about 6% to about 35% by weight of the second layer. An eleventh embodiment is any combination of the first through tenth embodiments, wherein the carbon black is about 24.5% by weight of the second layer. A twelfth embodiment is any combination of the first through eleventh embodiments, wherein the carbon black is 100% solids. A thirteenth embodiment is any combination of the first to twelfth embodiments, wherein the second layer further comprises about 25% to about 30% water by weight of the second layer. A fourteenth embodiment is any combination of the first to thirteenth embodiments, wherein the second layer further comprises a dispersant. A fifteenth embodiment is any combination of the first through fourteenth embodiments, wherein the second layer further comprises a suspending agent. A sixteenth embodiment is any combination of the first through fifteenth embodiments, wherein the second layer further comprises an aqueous dispersion of an acrylic ester-styrene copolymer. A seventeenth embodiment is any combination of the first through sixteenth embodiments, wherein the second layer further comprises an antifoaming agent. An eighteenth embodiment is any combination of the first through seventeenth embodiments, wherein the second layer further comprises a thickener. In another aspect, there is provided an electrical cable comprising a tape of any combination of the first to eighteenth embodiments.

[0024] In another aspect, a first embodiment is a semiconductive tape for use with an electrical cable. The tape includes a fabric and activated carbon or carbon black. The tape has a resistivity of about 1 million (ohm / cm) or less and a static coefficient of friction of at least about 1.00. The second embodiment is the first embodiment, wherein the resistance is about 100 (Ω / cm) or less. A third embodiment is any combination of the first and second embodiments, wherein the coefficient of static friction is at least about 1.25. The fourth embodiment is any combination of the first to third embodiments, with the static friction coefficient being about 1.4 to about 1.5. A fifth embodiment is any combination of the first through fourth embodiments, wherein the dynamic coefficient of friction is at least about 0.7. A sixth embodiment is any combination of the first through fifth embodiments, wherein the dynamic coefficient of friction is at least about 0.8. A seventh embodiment is any combination of the first to sixth embodiments, in which the tape includes carbon black. An eighth embodiment is any combination of the first through seventh embodiments, wherein the carbon black is substantially solid. A ninth embodiment is any combination of the first through eighth embodiments, further comprising an acrylic copolymer dispersed in water. A tenth embodiment is any combination of the first to ninth embodiments, wherein the carbon black is hydrophobic. An eleventh embodiment is any combination of the first through tenth embodiments, wherein the acrylic copolymer and carbon black are mixed together to form the mixture. A twelfth embodiment is any combination of the first through eleventh embodiments, wherein the solids content of the mixture is from about 30% to about 60%. A thirteenth embodiment is any combination of the first through twelfth embodiments, with a solids content of about 45%. A fourteenth embodiment is any combination of the first through thirteenth embodiments, wherein the carbon black is from about 6% to about 35% by weight of the mixture. A fifteenth embodiment is any combination of the first through fourteenth embodiments, wherein the carbon black is about 24.5% by weight of the mixture. In another aspect, there is provided an electrical cable comprising a tape of any combination of the first to fourteenth embodiments.

[0025] In another aspect, a first embodiment is a method of making a semiconductive tape, the method including forming a first layer comprising a fabric, forming a second layer comprising activated carbon or carbon black, and bonding the first layer to the second layer. A second embodiment is the first embodiment, further comprising forming a mixture of activated carbon or carbon black and a polymer, and applying the mixture to a surface of the first layer. A third embodiment is any combination of the first and second embodiments, further comprising forming a third layer comprising activated carbon or carbon black, and bonding the third layer to the first layer. A fourth embodiment is any combination of the first to third embodiments, wherein the first layer has a first surface and a second surface opposite the first surface, the second layer is bonded to the first surface, and the third layer is bonded to the second surface. A fifth embodiment is any combination of the first through fourth embodiments, wherein the polymer comprises an acrylic copolymer dispersed in water. A sixth embodiment is any combination of the first through fifth embodiments, further comprising crosslinking the acrylic copolymer to bond the second layer to the first layer. A seventh embodiment is any combination of the first to sixth embodiments, wherein the second layer comprises carbon black. An eighth embodiment is any combination of the first to seventh embodiments, wherein the carbon black is hydrophobic. A ninth embodiment is any combination of the first to eighth embodiments, wherein the solids content of the second layer is about 30% to about 60%. A tenth embodiment is any combination of the first through ninth embodiments, with a solids content of about 45%. An eleventh embodiment is any combination of the first to tenth embodiments, wherein the carbon black is about 6% to about 35% by weight of the second layer. A twelfth embodiment is any combination of the first through eleventh embodiments, wherein the carbon black is about 24.5% by weight of the second layer. A thirteenth embodiment is any combination of the first through twelfth embodiments, wherein the carbon black is 100% solids. A fourteenth embodiment is any combination of the first to thirteenth embodiments, wherein the second layer further comprises about 25% to about 30% water by weight of the second layer. A fifteenth embodiment is any combination of the first through fourteenth embodiments, wherein the second layer further comprises an aqueous dispersion of an acrylic ester-styrene copolymer. A sixteenth embodiment is any combination of the first through fifteenth embodiments, wherein the fabric comprises a material selected from the group consisting of nylon, polyester, synthetic fibers, natural fibers, and synthetic polymers.

Claims

1. a first layer comprising a fabric; a second layer in contact with the first layer, the second layer comprising a polymer and activated carbon or carbon black; A semiconductive tape comprising:

2. The tape of claim 1 , wherein the second layer comprises carbon black.

3. The tape of claim 1 , wherein the polymer comprises an electrically insulating material.

4. The tape of claim 1 , wherein the polymer comprises an acrylic copolymer dispersed in water.

5. The tape of claim 2 wherein the carbon black is hydrophobic.

6. 10. The tape of claim 1, further comprising a third layer comprising a polymer and activated carbon or carbon black, the first layer being disposed between the second and third layers.

7. 10. The tape of claim 1, wherein the fabric comprises a material selected from the group consisting of nylon, polyester, synthetic fibers, natural fibers, and synthetic polymers.

8. 10. The tape of claim 1, wherein the second layer has a solids content of about 30% to about 60%.

9. 9. The tape of claim 8, wherein the solids content is about 45%.

10. The tape of claim 2 , wherein the carbon black is about 6% to about 35% by weight of the second layer.

11. 3. The tape of claim 2, wherein the carbon black is about 24.5% by weight of the second layer.

12. 3. The tape of claim 2, wherein the carbon black is 100% solids.

13. The tape of claim 1 , wherein the second layer further comprises about 25% to about 30% water by weight of the second layer.

14. The tape of claim 1 , wherein the second layer further comprises a dispersant.

15. The tape of claim 1 , wherein the second layer further comprises a suspending agent.

16. The tape of claim 1, wherein the second layer further comprises an aqueous dispersion of an acrylate-styrene copolymer.

17. The tape of claim 1 , wherein the second layer further comprises an antifoaming agent.

18. The tape of claim 1 , wherein the second layer further comprises a thickener.

19. An electrical cable comprising the tape of claim 1.

20. 1. A semi-conductive tape for use on electrical cables, comprising: Fabric and Activated carbon or carbon black; Including, The tape has a resistivity of about 1 million (ohm / cm) or less and a static coefficient of friction of at least about 1.

00. tape.

21. 21. The tape of claim 20, wherein the resistivity is about 100 (ohm / cm) or less.

22. 21. The tape of claim 20, wherein the static coefficient of friction is at least about 1.

25.

23. 21. The tape of claim 20, wherein the static coefficient of friction is from about 1.4 to about 1.

5.

24. 21. The tape of claim 20, wherein the tape has a dynamic coefficient of friction of at least about 0.

7.

25. 25. The tape of claim 24, wherein the dynamic coefficient of friction is at least about 0.

8.

26. 21. The tape of claim 20, wherein the tape comprises carbon black.

27. 27. The tape of claim 26, wherein the carbon black is substantially solid.

28. 21. The tape of claim 20, further comprising an acrylic copolymer dispersed in water.

29. 27. The tape of claim 26, wherein the carbon black is hydrophobic.

30. 30. The tape of claim 28, wherein the acrylic copolymer and the carbon black are mixed together to form a mixture.

31. 31. The tape of claim 30, wherein the solids content of the mixture is from about 30% to about 60%.

32. 32. The tape of claim 31, wherein the solids content is about 45%.

33. 31. The tape of claim 30, wherein the carbon black is about 6% to about 35% by weight of the mixture.

34. 34. The tape of claim 33, wherein the carbon black is about 24.5% by weight of the mixture.

35. An electrical cable comprising the tape of claim 20.

36. A method for manufacturing a semiconductive tape, comprising: forming a first layer comprising a fabric; forming a second layer comprising activated carbon or carbon black; bonding the first layer to the second layer; A method comprising:

37. 37. The method of claim 36, further comprising forming a mixture of the activated carbon or carbon black and a polymer, and applying the mixture to a surface of the first layer.

38. 37. The method of claim 36, further comprising forming a third layer comprising activated carbon or carbon black, and bonding the third layer to the first layer.

39. 39. The method of claim 38, wherein the first layer comprises a first surface and a second surface opposite the first surface, the second layer being bonded to the first surface, and the third layer being bonded to the second surface.

40. 38. The method of claim 37, wherein the polymer comprises an acrylic copolymer dispersed in water.

41. 40. The method of claim 39, further comprising crosslinking the acrylic copolymer to bond the second layer to the first layer.

42. 37. The method of claim 36, wherein the second layer comprises carbon black.

43. 43. The method of claim 42, wherein the carbon black is hydrophobic.

44. 37. The method of claim 36, wherein the second layer has a solids content of about 30% to about 60%.

45. 43. The method of claim 42, wherein the solids content is about 45%.

46. 42. The method of claim 41, wherein the carbon black is about 6% to about 35% by weight of the second layer.

47. 42. The method of claim 41, wherein the carbon black is about 24.5% by weight of the second layer.

48. 43. The method of claim 42, wherein the carbon black is 100% solids.

49. 37. The method of claim 36, wherein the second layer further comprises about 25% to about 30% water by weight of the second layer.

50. 37. The method of claim 36, wherein the second layer further comprises an aqueous dispersion of an acrylic ester-styrene copolymer.

51. 37. The method of claim 36, wherein the fabric comprises a material selected from the group consisting of nylon, polyester, synthetic fibers, natural fibers, and synthetic polymers.

Images