Overhead conductor with high-temperature-resistant cured coating

Abstract

An overhead conductor includes a bare conductor coated with a cured coating composition formed from a one-component coating dispersion. The curable coating composition comprises silica or a derivative thereof, one or more metals of Groups IA-IIIA of the Periodic Table, one or more acrylics, titanium dioxide, and optionally barium sulfate. A method of making a coated overhead conductor includes preparing a one-component coating dispersion, applying the coating dispersion to a bare conductor, and curing the coating dispersion to form the coated overhead conductor. The one-component coating dispersion comprises silica, one or more metal silicates, one or more acrylics, titanium dioxide, water, and optionally barium sulfate.

Description

Technical Field

[0001] The present application relates to overhead conductors. More specifically, the present application relates to overhead conductors having a cured coating that is resistant to high temperature and water aging. The present application also relates to a method of making a coated overhead conductor, the method comprising applying a one-component coating dispersion and curing the coating dispersion at ambient temperature. Background Art

[0002] As the demand for electricity continues to grow, the need for higher capacity transmission and distribution lines is also growing. The amount of power that a transmission line can deliver depends on the current carrying capacity (amperage capacity) of the line. The ampacity of a line is limited by the maximum safe operating temperature of the bare conductors that carry the current. Exceeding this temperature can result in damage to the conductors or to accessories attached to the line. In addition, the conductor heats up due to ohmic losses and solar heat, and it cools by conduction, convection, and radiation. The amount of heat generated due to ohmic losses depends on the current (I) passing through it and its resistance (R), as per the relationship Ohmic losses = I 2 R. Resistance (R) itself depends on temperature. Higher current and temperature lead to higher resistance, which in turn leads to greater electrical losses in the wire.

[0003] Although several coatings have been proposed to reduce the operating temperature of the conductor, increase the thermal emissivity of the conductor and / or improve the durability of the conductor, there is still a need for an overhead conductor having a coating resistant to high temperature and water aging, the coating being formed from a single component (or one pot composition) water-based composition curable at ambient temperature. There is also a need for an overhead conductor having a coating that exhibits long-term heat resistance at temperatures exceeding 150°C.

[0004] U.S. Patent No. 10,586,633 relates to an overhead conductor surface modified with a coating. The coating composition comprises a binder (e.g., a metal silicate or colloidal silica in an amount of 20-60 wt% of the dry composition) and a heat radiating agent (e.g., titanium oxide or silicon oxide in an amount of 10-20 wt% of the dry composition). If any organic ingredients are used, they should be less than about 10 wt% of the dry composition. Summary of the invention

[0005] Thus, one exemplary embodiment of the present invention provides an overhead conductor comprising a bare conductor coated with a cured coating composition comprising from about 30% to about 65% by dry weight of silicon dioxide or a derivative thereof; from about 10% to about 20% by dry weight of one or more acrylates; from about 5% to about 45% by dry weight of titanium dioxide; and from about 1% to about 25% by dry weight of at least one metal selected from Groups IA-IIIA of the Periodic Table of Elements.

[0006] The present invention may also provide a method for making a coated overhead conductor, the method comprising preparing a one-component coating dispersion, applying the one-component coating dispersion to a bare overhead conductor; and curing the coating dispersion at ambient temperature to form a coated overhead conductor. The one-component coating dispersion comprises about 1% to about 25% by weight of silicon dioxide; about 0.3% to about 10% by weight of one or more metal silicates, wherein the metal of the metal silicate is selected from Groups IA-IIIA of the Periodic Table of Elements; about 3% to about 10% by weight of one or more acrylates; about 2% to about 25% by weight of titanium dioxide; and about 30% to about 70% by weight of water.

[0007] Other objects, advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A more complete understanding of the present invention and its many associated advantages will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0009] Figure 1 is a cross-sectional view of a wire according to one embodiment of the present invention;

[0010] Figure 2 is a cross-sectional view of a wire according to one embodiment of the present invention;

[0011] Figure 3 is a cross-sectional view of a wire according to one embodiment of the present invention;

[0012] Figure 4 is a cross-sectional view of a wire according to one embodiment of the present invention;

[0013] Figure 5 is a diagram showing a continuous process of the present invention;

[0014] Figure 6 is a diagram showing a cross section of a filled die;

[0015] Figure 7 is a diagram showing a plan view of a filled die; and

[0016] Figure 8 is a diagram showing an exploded view of a filled die. DETAILED DESCRIPTION

[0017] In this specification and the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, etc. are to be understood as being modified in all cases by the term "about". Likewise, all ranges include any combination of the maximum and minimum values ​​disclosed, and include any intermediate ranges therein, which may or may not be expressly enumerated herein.

[0018] In at least one of the described aspects, the invention may be implemented according to one or more embodiments of the invention, optionally in combination.

[0019] In this specification and the appended claims, the wording "a" or "an" should be interpreted as including one or at least one, and the singular form also includes the plural form unless it is obvious that it is otherwise intended. This is only for convenience, giving a general meaning of the invention.

[0020] As used herein, all percentages (%) are by weight of the total composition unless otherwise indicated. Likewise, as used herein, the term "wet" refers to the relative percentage of the coating dispersion in the medium (i.e., water); and "dry" refers to the relative percentage of the dry coating composition before the addition of the dispersion medium or the cured coating composition upon elimination of the dispersion medium. In other words, the dry percentage is the percentage without regard to the dispersion medium.

[0021] As used herein, the term "ambient temperature" refers to a temperature of 5°C to 50°C.

[0022] As will be described herein, an overhead conductor is disclosed, comprising a bare conductor coated with a cured coating composition. In certain embodiments, the cured coating composition may comprise one or more of silicon dioxide and its derivatives, acrylates, titanium oxide, at least one metal selected from Groups IA-IIIA of the periodic table, and optionally barium sulfate. Such a cured coating composition may be heat resistant at 250°C for 7 days. Such a cured coating composition may be water resistant at 90°C for 7 days. The cured coating composition may also pass a mandrel bend test after heat aging at 250°C for 7 days and / or after water aging at 90°C for 7 days. The cured coating composition may be formed from a one-component coating dispersion of the present invention, wherein such a one-component coating dispersion may be cured at ambient temperature and have a shelf life of about 24 hours or longer.

[0023] As used herein, the term "pot life" refers to the time span over which a one-component coating dispersion retains its viscosity.

[0024] Suitable examples of silica may include amorphous silica, colloidal silica and crystalline silica such as quartz, but it will be appreciated that any of a variety of suitable types of silica may be used in the coating composition. In certain embodiments, the average particle size of the silica of the coating of the present invention is 0.05 microns to 10 microns.

[0025] In certain embodiments, the one-component coating dispersion may contain from about 1% to about 25% by weight of silica; in certain embodiments, from about 5% to about 22% by weight of silica; and in certain embodiments, from about 10% to about 21% by weight of silica. In certain embodiments, the method may include using silica in the form of a silica sol or colloidal silica.

[0026] Suitable examples of silicon dioxide derivatives may include silicates of at least one metal selected from Group IA-IIIA elements of the periodic table. Suitable examples of such silicates may include, but are not limited to, potassium silicate, sodium silicate, lithium silicate, magnesium silicate, aluminum silicate, and hydrated forms and combinations thereof.

[0027] In certain embodiments, a one-component coating dispersion may include from about 0.3% to about 10% by weight of one or more silicates.

[0028] The cured coating compositions of the present invention may contain from about 30% to about 65% by dry weight of silica or a derivative thereof. In certain embodiments, the cured coating compositions may contain from about 35% to about 60% by dry weight of silica or a derivative thereof.

[0029] The cured coating composition coating of the wire of the present invention may contain about 1% to about 25% by dry weight of one or more metals selected from Groups IA-IIIA of the Periodic Table of Elements. In certain embodiments, the cured coating composition coating of the wire may contain about 2% to about 10% by dry weight of such metals as described herein. Suitable examples of metals may include, but are not limited to, aluminum, potassium, sodium, lithium, magnesium, calcium, and combinations thereof.

[0030] Suitable examples of acrylates may include hydroxy acrylates (e.g. hydroxyethyl acrylate); epoxy acrylates; (meth)acrylate homopolymers or (meth)acrylate copolymers (e.g. butyl acrylate-methyl methacrylate copolymers) or styrene-acrylate copolymers, polyacrylic acid or its salts such as sodium polyacrylate, but it will be appreciated that any of a variety of suitable types of acrylates may be used.

[0031] In certain embodiments, the one-component coating dispersion may include from about 3% to about 10% by weight acrylate; in certain embodiments, from about 4% to about 8% by weight acrylate; and in certain embodiments, about 6% by weight acrylate.

[0032] In certain embodiments, the cured coating compositions of the present invention may include from about 10% to about 20% by dry weight of acrylate; and in certain embodiments, from about 10% to about 16% by dry weight of acrylate.

[0033] In certain embodiments, the titanium dioxide may be rutile titanium dioxide, but it will be appreciated that any of a variety of suitable types of titanium dioxide may be used.

[0034] In certain embodiments, the one-component coating dispersion may include from about 2% to about 25% by weight titanium dioxide; and in certain embodiments, from about 5% to about 22% by weight titanium dioxide.

[0035] In certain embodiments, the cured coating composition coating of the wire of the present invention may comprise from about 5% to about 45% by dry weight of titanium dioxide; and in certain embodiments from about 8% to about 40% by dry weight of titanium dioxide.

[0036] In certain embodiments, both the cured coating composition and the one-component coating dispersion may further comprise barium sulfate. In certain embodiments, the one-component coating dispersion may comprise 0.5% to about 9% by weight of barium sulfate; and in certain embodiments up to about 5% by weight of barium sulfate. In certain embodiments, the cured coating composition may comprise 1% to about 15% by dry weight of barium sulfate; and in certain embodiments up to about 9% by dry weight of barium sulfate.

[0037] Both the cured coating composition and the one-component coating dispersion may also contain other optional ingredients such as defoamers, anti-wear aids, stabilizers, colorants, surfactants, emissivity agents and infrared (IR) reflecting additives.

[0038] Suitable examples of defoamers (or antifoaming agents) are 2-octanol, oleic acid, paraffin wax, amide wax, sulfonated oil, organic phosphoric acid ester, silicone oil, mineral oil and dimethylpolysiloxane.

[0039] Suitable examples of wear-resistant additives may include, but are not limited to, aluminum oxide, mica, calcium carbonate, and combinations thereof. In certain embodiments, the average particle size of suitable additives may be about 50 microns or less; about 20 microns or less in certain embodiments; and about 5 microns or less in certain embodiments.

[0040] In certain embodiments, the one-component coating dispersion may contain from about 1% to about 10% filler by weight; and in certain embodiments, from about 3% to about 5% filler by weight. In certain embodiments, the cured coating composition may contain from about 5% to about 15% filler by dry weight; and in certain embodiments, from about 7% to about 12% filler by dry weight.

[0041] Suitable examples of colorants may include, but are not limited to, cadmium yellow, cadmium red, cadmium green, cobalt orange, cobalt blue, azure blue, azurite, malachite, Paris green, phthalocyanine blue BN, phthalocyanine green G, viridian, sanguine, iron oxide pigments (e.g., red iron, red oxide, iron-rich rough ochre, iron-rich burnt ochre, rough umber, burnt umber and Venetian red), Prussian blue, ultramarine, zinc pigments (zinc white, zinc ferrite), and combinations thereof. In certain embodiments, the concentration of one or more colorants in the cured coating composition may be about 0.02%-1% by dry weight.

[0042] Suitable examples of stabilizers may include dispersion stabilizers, but it will be appreciated that any of a variety of suitable types of stabilizers may be used in the cured coating composition. In certain embodiments, one or more stabilizers may be present in the cured coating composition at a concentration of about 0.01% to about 2% by dry weight.

[0043] Suitable examples of IR reflective additives may include, but are not limited to, barium titanate, cobalt, aluminum, bismuth, lanthanum, neodymium, niobium, vanadium, iron, chromium, zinc, manganese, and nickel-based metal oxides and ceramics. In certain embodiments, one or more IR reflective additives may be present in the cured coating composition at a concentration of about 0.1% to about 5% by dry weight.

[0044] Suitable examples of surfactants may include, but are not limited to, cationic, anionic or nonionic surfactants, and fatty acid salts. In certain embodiments, one or more surfactants may be present in the cured coating composition at a concentration of about 0.05% to about 0.5% by dry weight.

[0045] Suitable examples of the emissive agent may include zirconium oxide metal oxides (such as aluminum oxide, magnesium oxide, calcium oxide, boron oxide, iron oxide, manganese oxide, copper chromium oxide and chromium oxide) or metal carbides (such as boron carbide, silicon carbide), boron nitride, silicon tetraboride, molybdenum disilicide, zirconium diboride and copper chromate. Titanium oxide and silicon dioxide may also act as emissive agents.

[0046] The exemplary coating dispersions described herein can be prepared and stored as a one-component coating dispersion. In certain embodiments, the shelf life of the one-component coating dispersion can be at least 24 hours. In certain embodiments, the one-component coating dispersion can have a viscosity of about 10 seconds to about 35 seconds when measured using a Zahn No. 3 cup.

[0047] Figure 1 , 2, 3 and 4 show different bare overhead conductors according to certain embodiments. Overhead conductors 100, 200, 300 and 400 may generally include only one or more conductive wires 120, 210, 320 and 410. Figure 1-4Each overhead conductor shown may include a cured coating (130, 220, 330 and 420) formed from the composition described herein. In addition, in certain embodiments, for example Figure 1 and 3 As shown, the overhead conductors may be formed as aluminum conductor steel reinforced (ACSR) cables in which conductive wires 120, 320 surround steel strength members 110, 310, respectively. Figure 2 and 4 The overhead conductors can be all-aluminum conductor (AAC) cables or all-aluminum alloy conductor (AAAC) cables.

[0048] In embodiments, the core 110, 310 may be steel, invar, a composite material, or any other material that provides strength to the conductor. In other embodiments, the conductive wire 120, 210, 320, 410 may be made of any suitable conductive material, including copper, copper alloys, aluminum, aluminum alloys including aluminum type 1000, 6000 series alloy aluminum, aluminum-zirconium alloys, carbon nanotubes, graphene, or any other conductive material.

[0049] Composite core conductors may be used due to lower sag at higher operating temperatures than all-metal composite conductors and their higher strength-to-weight ratio. Composite materials are based on glass fibers, carbon fibers, polymer fibers, aluminum reinforced alumina fibers, or any other material that can provide strength and low sag to the conductor. Polymer coatings may also or alternatively be used in composite core conductor designs. Non-limiting examples of composite cores may be found in U.S. Patent No. 7,015,395; U.S. Patent No. 7,438,971; U.S. Patent Application No. 2012 / 0186851; U.S. Patent No. 7,683,262; and U.S. Patent Application No. 2012 / 0261158, each of which is incorporated herein by reference.

[0050] The one-component coating dispersion can be made in a high speed disperser (HSD), a ball mill or a bead mill or using other techniques known in the art. In some examples, the one-component coating dispersion is formed by combining silicon dioxide, one or more silicates of one or more metals selected from Groups IA-IIIA of the periodic table, one or more acrylates, and titanium dioxide and one or more other optional ingredients such as barium sulfate in some embodiments, and using water as the dispersion medium. High speed mixing can be performed until the desired dispersion is achieved. In such an embodiment, the one-component coating dispersion can contain about 30% to about 70% by weight of water. Thus, the coating dispersion formed can be a suspension having a total solids content of about 30% to 70%.

[0051] In certain embodiments, the surface of the bare overhead conductor can be prepared before applying the one-component coating dispersion. For example, the preparation method can include chemical treatment, pressurized air cleaning, hot water or steam cleaning, brushing, heat treatment, sandblasting, ultrasonic, deglaring, solvent wiping and / or plasma treatment. In one embodiment, the surface of the bare overhead conductor can be deglared by sandblasting.

[0052] In certain embodiments, the one-component coating dispersion can be applied by a spray gun at a pressure of about 0.7 atmospheres to about 3 atmospheres, using controlled air pressure. In such an embodiment, the spray gun nozzle can be placed perpendicular to the conductor direction (e.g., at an angle of about 90°) to deliver a uniform coating to the bare overhead conductor. In some cases, two or more guns can also be used to more efficiently deliver the coating. The coating thickness and density can be controlled by the viscosity of the mixture, the gun pressure, and the wire speed. During the coating application process, the overhead wire temperature can be maintained at ambient temperature. When the coating is applied to an overhead conductor in operation, depending on the material of the conductor, the conductor may reach a temperature of 90°C or higher, which is harmless for coating application.

[0053] Alternatively, in certain embodiments, the one-component coating dispersion can be applied to the bare overhead conductor by one or more of dipping, brushing, foam applicator, or by roller. For example, in a dip coating method, the conductor can be dipped into the one-component coating dispersion to allow the dispersion to completely coat the conductor. The conductor can then be removed from the one-component coating dispersion and dried.

[0054] After application, the one-component coating dispersion on the overhead conductor can be cured. In certain embodiments, the one-component coating dispersion can be cured at ambient temperature. However, it will be understood that in certain embodiments, the one-component coating dispersion can be exposed to high temperatures to promote the curing process. In certain embodiments, the one-component coating dispersion can be cured at ambient temperature in less than 24 hours; in certain embodiments, the one-component coating dispersion can be cured at ambient temperature in less than 2 hours; in certain embodiments, the one-component coating dispersion can be cured at ambient temperature in less than 1 hour; and in certain embodiments, the one-component coating dispersion can be cured at ambient temperature in less than 30 minutes. The dispersion of the present invention is intended to be suitably cured in the "touch dry" stage, wherein the coating undergoes sufficient curing so that it can be lightly touched without any finger adhesion. As used herein, the "touch dry" stage refers to the "dry" stage between the "non-stick" and "dry hard" stages as defined in ASTM D-1640 (1995).

[0055] It is to be understood that the one-component coating dispersion also can be applied to the wire installed and currently in use.For example, existing wire can be coated with an automatic or semi-automatic coating robot system.In certain embodiments, the automatic system can include a clean wire surface, the one-component coating dispersion is applied to the wire surface, and the dispersion is solidified under ambient conditions without further additional steps.In certain embodiments, the automatic system can further include a drying tool such as a heater, a fan or a dry gas blower, to slow down (ease) and / or accelerate the solidification of the dispersion.

[0056] The one-component coating dispersion can be applied to the conductor in several ways. For example, the one-component coating dispersion can be applied by first coating a single wire and then assembling it in a bare overhead conductor. It will be appreciated that all of the wires of the conductor can be coated, or more economically, only the outermost wires of the conductor can be coated. Alternatively, the coating can be applied only to the outer surface of the bare overhead conductor, rather than to a single wire. In certain embodiments, the entire outer surface of the bare conductor can be coated. In other embodiments, only a portion of the bare conductor can be coated.

[0057] In addition, the one-component coating dispersion can be applied to overhead power line accessories. For example, a transformer substation can include multiple accessories, including circuit breakers and transformers such as current coupling transformers. The one-component coating dispersion described herein can be applied to one or more of these accessories. It is understood that other power transmission line accessories can also benefit from such coatings, including end / end products, hinged joints / joints, suspension and support products, motion control / vibration products (sometimes called shock absorbers) as non-limiting examples, guying products, wildlife protection and deterrent products, wire and compression joint repair parts, transformer substation products, clips and corona rings. The one-component coating dispersion can be applied to such accessories in any suitable manner. For example, the one-component coating dispersion can be applied to the accessory after cleaning the surface of a new accessory. Alternatively, the one-component coating dispersion can also be applied to the accessory after cleaning the surface of an existing accessory. In each such embodiment, the one-component coating dispersion can be cured by exposure to ambient temperature, or alternatively, exposed to high temperatures provided by, for example, infrared heaters to cure.

[0058] It will be appreciated that the coating may be applied in a batch process, a semi-batch process or a continuous process. Figure 5A continuous coating process is shown, and an electrical conductor 512 is shown, which is sent from an entry winding roll 502 to a pre-treatment unit 504 and a coating unit 506. The pre-treatment unit 504 can prepare the surface of the conductor to apply a one-component coating dispersion in the coating unit 506. In certain embodiments, after applying the one-component coating dispersion, the conductor can be dried via a drying / curing unit 508. However, it will be understood that, as described above, the one-component coating dispersion can be cured at ambient temperature. The conductor 512 can be wound on a roller 511.

[0059] In the pre-treatment unit 504, the surface of the conductor 512 can be prepared by media blasting. Such media can include sand, glass beads, ilmenite, steel shot and other suitable media. Media blasting can be followed by air wiping to blow away particulate material on the conductor 512. In some embodiments, mechanical methods and / or metal brushing can be used to prepare the conductor surface.

[0060] Air wiping can use a jet to blow air onto the wire 512 at an angle and in a direction opposite to the direction of travel of the wire 512. The air jet can produce a 360° air ring that adheres to the circumference of the wire 512 and wipes the surface with high-speed air. In such an example, any particles attached to the wire 512 will be wiped and blown back into the pretreatment unit 504 as the wire leaves the pretreatment unit 504. In certain embodiments, a suitable air jet can be operated at about 4atm to about 7atm; in certain embodiments, at about 5atm to about 6atm; and in certain embodiments, at about 5.5atm. In certain embodiments, the speed of the air jet (when exiting the nozzle) can be about 200kmh-about 800kmh; in certain embodiments, about 240kmh-about 640kmh; and in certain embodiments, about 400kmh-about 550kmh. After air wiping, in some embodiments, the number of particles with a size greater than about 10 microns remaining on the surface of the conductor can be about 11,000 particles / square meter or less; and in some embodiments, about 1,100 particles / square meter or less. After air wiping, the conductor can be heated, for example, by a heating oven, UV, IR, electron beam, induction heating, pressurized steam heating, open flame, etc. The heating can be done with a single or multiple units. In one embodiment, the flame can be directly applied to preheat the conductor. Here, the cable can be directly passed through the flame to heat the cable surface to a temperature above the ambient temperature. The high heating temperature in the pretreatment allows a lower heating temperature to be used in the drying / curing unit. However, the heating should not be so severe in cases where it affects the quality of the coating (for example, by affecting adhesion, flatness, blistering, etc.). In some embodiments, the conductor 512 should not be heated to above about 140°C; and in some embodiments not above about 120°C.

[0061] After the surface of the conductor 512 has been prepared, the surface can be ready for coating. The coating process can be performed in a coating unit where the cable is passed through a filled die that deposits a one-component coating dispersion onto the prepared surface. Figure 6-8 Shown is a ring-shaped filled die 601. Single-component coating dispersion can be supplied to die 601 via tube 606. When wire 512 passes through the central opening 604 of the filled die 601, the single-component coating dispersion coats wire 512 via one or more open ports 602 in the inner surface of die 601. In certain embodiments, the filled die 601 can include two or more, four or more, or six or more open ports 602 evenly spaced around the inner surface circumference. After wire 512 leaves the filled die, wire 512 can be wiped with another air to remove unnecessary single-component coating dispersion and single-component coating dispersion is evenly spread around the wire. In the case of stranded wire, air wiping can make coating penetrate into the groove between strands on the wire surface. This air wiping can be operated using conditions similar to the air wiping in pre-treatment unit 504.

[0062] As described above, after the conductor 512 is coated, the coating can be cured at ambient temperature. In certain embodiments, the conductor 512 can be passed through a drying / curing unit 508, such as Figure 5 As shown. In an optional embodiment, drying / curing can be done using air or hot air. In certain embodiments, the drying / curing unit can be operated at a line speed of about 2.5m / min-152.5m / min; and in certain embodiments about 3m / min-122m / min. The air temperature and line speed can be selected based on the metal alloy used in the conductor 512. The drying method can be a step-by-step drying method, a fast drying method and / or a heating method. As described above, drying can also be done by other techniques (e.g., UV radiation, IR radiation, electron beam curing), which will accelerate the method without weakening the method or the final coating. The drying method can occur in a single unit or in multiple units. The drying method can also occur vertically, horizontally or at a specific angle. In certain embodiments, drying / curing can occur by heating to 200°C or higher without weakening the coating. After drying / curing, the coated overhead wire can be wound on a roller 511 for storage.

[0063] After application to the conductor 512 and curing, the resulting coating may have a thickness of less than about 100 microns in certain embodiments, and about 10-30 microns in certain embodiments. In certain embodiments, the resulting coating may be non-white, with an L (lightness) value of about 20 or greater. The coating may be non-conductive, semi-conductive, or conductive.

[0064] Without further explanation, it is believed that those skilled in the art can use the foregoing description and the following exemplary embodiments to make and utilize the compounds of the present invention and practice the claimed methods. The following examples are given to illustrate the present invention. It should be understood that the present invention is not limited to the specific conditions or details described in this example.

[0065] Example

[0066] Table 1 shows the formulations of comparative examples 1-5, while Table 2 shows the formulations of inventive examples 1 and 2. Each example formulation combines the components in the weight percentages shown, and is fully stirred and blended at high speed for 5 minutes to form. Tables 1 and 2 also show the viscosity of each example formulation.

[0067] Table 1. Coating formula of comparative example

[0068]

[0069] Table 2. Coating formula of the present invention

[0070]

[0071] Tables 1 and 2 show that each of the one-component coating dispersions formed from the formulations of Examples 1 and 2 of the present invention can exhibit a desirable viscosity (e.g., about 10 seconds to about 35 seconds when measured with a Zahn No. 3 cup). In addition to being necessary for the proper application of the one-component coating dispersion, particularly when a thin coating is sought, a low run-off time (corresponding to a low viscosity) in the Zahn cup test means a suitably long storage life, i.e., the dispersion does not readily separate. As a result of the results, the one-component coating dispersions formed from the formulations of Examples 1 and 2 of the present invention and Comparative Examples 1 and 3 can provide a storage life of at least 24 hours. The one-component coating dispersions formed from the formulations of Comparative Examples 2, 4, and 5 cannot achieve the desired viscosity because they separate or even become solid within 24 hours after preparation. Comparative Examples 2, 4, and 5, while potentially useful for providing a suitable coating, cannot be one-component coating dispersions because one or more of their components must be added no more than 1 hour prior to application to the bare conductor to form a coated overhead conductor.

[0072] The formulations of each of Comparative Examples 1-5 and Inventive Examples 1 and 2 were applied to aluminum strips and allowed to cure at ambient temperature. Testing was performed and their results are shown in Table 3 below.

[0073] Table 3. Overhead conductor test results

[0074]

[0075] As shown in Table 3, the overhead conductors coated with the coatings formed from the formulations of Examples 1 and 2 of the present invention performed better than the overhead conductors coated with the coatings formed from the formulations of Comparative Examples 1-5. For example, when subjected to each of heat aging and water aging, the conductors having the coatings formed from the formulations of Examples 1 and 2 of the present invention passed the mandrel bend and fingernail scratch tests. In contrast, the overhead conductors coated with the coatings formed from the formulations of Comparative Examples 1-5 failed to pass all tests after undergoing heat aging and water aging.

[0076] program

[0077] Viscosity measurements were performed according to ASTM D 4212 (1999).

[0078] The heat aging performance of the coated overhead conductors was conducted by placing the coated overhead conductors in an air circulating oven maintained at 250°C for a period of 1 day and 7 days. After the heat aging was completed, each coated overhead conductor was placed at room temperature (e.g., 21°C) for a period of 24 hours. The coated overhead conductors were then bent over a 5" cylindrical mandrel and the coating of each of these overhead conductors was observed for any visible cracks. If no visible cracks were present when bent over the 5" mandrel, the tested overhead conductor was considered to have "passed".

[0079] Water aging is evaluated by immersing the sample (coated aluminum strip) in 90°C water for a specified time (1 day or 7 days or 14 days or 30 days). The sample is then removed and conditioned at room temperature for 24 hours before testing on a mandrel as described above, and / or performing a fingernail scratch test. The results are compared with those obtained before immersion in water to determine the water resistance of the coating.

[0080] Fingernail scratching and rubbing is performed by attempting to dig into the cured coating surface with a fingernail. This test provides a comprehensive indication of hardness and abrasion resistance. If the coated surface adequately retains its coating when vigorously rubbed with a fingernail, the tested coating is considered to be "passed". For example, the designation "coating adhesion" in Table 3 represents a "passed" coating. If the coating cracks or peels off when vigorously rubbed with a fingernail, the tested coating is considered to be failed. For example, the designations "coating peeling" and "coating dissolution" in Table 3 represent "failed" coatings.

[0081] The dimensions and values ​​disclosed herein are not to be understood as being strictly limited to the exact numerical values ​​recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value.

[0082] It should be understood that each maximum numerical limit given throughout this specification includes each numerical lower limit, as if such numerical lower limits were expressly written herein. Each minimum numerical limit given throughout this specification will include each numerical upper limit, as if such numerical upper limits were expressly written herein. Each numerical range given throughout this specification will include each narrower numerical range that falls within such wider numerical range, as if such narrower numerical ranges were all expressly written herein.

[0083] Each document cited herein, including any cross-referenced or related patents or applications, is incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein, or that it alone, or in any combination with any other reference, teaches, suggests, or discloses any such invention. In addition, in the event that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to the term in this document shall prevail.

[0084] The description of the foregoing embodiments and examples has been provided for illustration. It is not intended to be exclusive or limited to the described form. In light of the above teachings, many changes are possible. Some of those changes have been discussed, and others will be understood by those skilled in the art. The selection and description of the embodiments are intended to illustrate different embodiments. Of course, the scope is not limited to the embodiments or embodiments described herein, but can be applied by those skilled in the art in any of the many applications and equivalent papers. On the contrary, it is intended to be limited in scope by the appended claims.

Claims

1. An overhead conductor comprising a bare conductor coated with a cured coating composition comprising: About 30% to 65% by dry weight of silicon dioxide or a derivative thereof; about 10% to about 20% by dry weight of one or more acrylates; about 5% to about 45% by dry weight titanium dioxide; and From about 1% to about 25% by dry weight of at least one metal selected from Groups IA-IIIA of the Periodic Table of the Elements.

2. The overhead conductor according to claim 1, wherein the silicon dioxide comprises one or more of amorphous silicon dioxide, colloidal silicon dioxide and crystalline silicon dioxide such as quartz.

3. The overhead conductor of claim 1, wherein the silicon dioxide derivative comprises one or more silicates.

4. The overhead conductor of claim 1, wherein the cured coating composition further comprises about 1% to about 15% by dry weight of barium sulfate.

5. The overhead conductor of claim 1, wherein the cured coating composition comprises from about 40% to about 60% by dry weight of silica or a derivative thereof.

6. The overhead conductor of claim 1, wherein the at least one metal comprises one or more of aluminum, potassium, sodium, lithium, magnesium, and calcium.

7. The overhead conductor according to claim 1, wherein the one or more acrylate substances are selected from hydroxy acrylate; epoxy acrylate; (meth) acrylate homopolymer or (meth) acrylate copolymer; polyacrylic acid or its salt.

8. The overhead conductor of claim 1, wherein the cured coating composition comprises from about 8% to about 40% by dry weight titanium dioxide.

9. The overhead conductor of claim 1, wherein the cured coating composition comprises up to about 9% by dry weight barium sulfate.

10. The overhead conductor of claim 1, wherein the cured coating composition further comprises at least one of a defoamer, a wear aid, a stabilizer, a colorant, a surfactant, an emissive, and an infrared (IR) reflective additive.

11. A method of manufacturing a coated overhead conductor, the method comprising: A one-component coating dispersion is prepared, the coating dispersion comprising: about 1% to about 25% by weight silicon dioxide; about 0.3% to about 10% by weight of one or more metal silicates, wherein the metal of the metal silicate is selected from Groups IA-IIIA of the Periodic Table of the Elements; about 3% to about 10% by weight of one or more acrylic acid esters; about 2% to about 25% by weight titanium dioxide; and about 30% to about 70% by weight water, applying the coating dispersion to a bare overhead conductor; and The coating dispersion is cured at ambient temperature to form the coated overhead conductor.

12. The method of claim 11, wherein the coating dispersion comprises from about 5% to about 22% by weight silica.

13. The method of claim 11, wherein the coating dispersion further comprises about 0.5% to about 9% by weight barium sulfate.

14. The method of claim 11, wherein the coating dispersion is capable of curing at ambient temperature in less than 1 hour.

15. The method of claim 11, wherein the coating dispersion has a shelf life of about 24 hours or more.

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