Insulated magnetic wire with low dielectric constant

Abstract

A magnetic wire having low dielectric constant insulation includes a conductor and at least one insulating layer formed around the conductor. The insulating layer includes a base polymeric material and one or more additives incorporated into the base polymeric material. The one or more additives include at least one of: (i) a polycyclic aromatic hydrocarbon; or (ii) a partially or fully hydrogenated compound of a polycyclic aromatic hydrocarbon. Additionally, one or more additives reduce the dielectric constant of the insulating layer relative to a control insulating layer formed only from the base polymer material.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 545,305, filed October 23, 2023, entitled “Magnet Wire with Low-Permittivity Insulation,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of this disclosure generally relate to magnetic wires, and more specifically, to magnetic wires comprising an insulating structure formed with one or more additives that reduce the dielectric constant and improve performance. Background Technology

[0004] Magnetic wire, also known as winding or magnetic winding, is widely used in various motors and equipment, such as inverter drive motors, motor starter generators, and transformers. Typically, magnetic wire is constructed by applying an electrically insulating structure to a metallic conductor (such as copper, aluminum, or alloy conductors). This insulation structure provides electrical integrity and prevents short circuits. Some magnetic wires include enamel insulation structures applied in continuous multi-layer coatings and cured in an oven. The enamel layers are usually applied in the form of a varnish containing thermosetting polymer materials suspended in a solvent; heating and curing removes almost all the solvent, leaving a solid polymer layer. Other magnetic wires include thermoplastic polymer insulation molten and extruded onto the conductor. Still others include combinations of thermosetting and thermoplastic insulation structures.

[0005] Regardless of the insulation system used on the magnetic wire (e.g., thermosetting enamel, thermoplastic, etc.), there is a desire to improve or enhance the electrical performance of the insulation structure. For example, the growing customer demands and expectations for certain magnetic wire applications (such as hybrid electric vehicles (HEVs) and / or automotive applications) necessitate improvements in the electrical performance of the magnetic wire insulation structure. Typically, it is desirable to increase the dielectric properties and / or partial discharge inception voltage (PDIV) of the magnetic wire. The PDIV of a magnetic wire generally refers to the voltage at which partial insulation breakdown can occur. Partial discharge typically begins in voids, cracks, or inclusions within the insulation layer; however, it can also occur along the surface of the insulating material. Once initiated, partial discharge gradually degrades the insulation material and eventually leads to electrical breakdown. Generally, insulating materials with lower dielectric constants have higher PDIV values.

[0006] Therefore, there are opportunities for improved magnetic wires, including low-dielectric-constant insulation structures that enhance electrical properties. Specifically, there are opportunities for improved magnetic wires having an insulation structure formed with one or more additives that reduce the dielectric constant of the insulation while increasing the partial discharge initiation voltage and / or dielectric properties of the magnetic wire. Attached Figure Description

[0007] A detailed description will be given with reference to the accompanying drawings. In the drawings, the leftmost digit(s) of a reference number indicates the first figure in which that reference number appears. The use of the same reference number in different figures indicates similar or identical items; however, various embodiments may employ elements and / or components not shown in the figures. Additionally, the accompanying drawings are provided to illustrate exemplary embodiments described herein and are not intended to limit the scope of this disclosure.

[0008] Figures 1A to 1D This is a cross-sectional view of an example magnetic wire structure including a low dielectric constant insulating structure according to an illustrative embodiment of the present disclosure.

[0009] Figures 2A to 2B This is a schematic diagram of an insulating layer incorporating additives to reduce the dielectric constant of the insulation, according to an illustrative embodiment of the present disclosure. Detailed Implementation

[0010] Various embodiments of this disclosure relate to magnetic wires comprising a conductor and a low-dielectric-constant insulating layer formed around the conductor. Various types of insulating structures can be formed around the conductor, including but not limited to thermosetting or thermosetting enamel insulating structures, thermoplastic insulating structures, or combinations of thermosetting and thermoplastic insulating structures. Additionally, at least one insulating layer may be incorporated with or formed using one or more additives that reduce the dielectric constant of the insulating structure. Therefore, the electrical properties of the insulating structure, such as the partial discharge initiation voltage (“PDIV”) and / or dielectric characteristics, may be enhanced.

[0011] As desired in the various embodiments, a variety of different additives and / or combinations of additives can be incorporated into one or more insulating layers, and / or used to form one or more insulating layers (i.e., incorporated into the material used to form the insulating layer) to reduce the dielectric constant of the insulating layer. In some embodiments, one or more additives can be incorporated into (e.g., mixed into, laminated into, coated into, etc.) a single insulating layer (e.g., a thermosetting layer, thermoplastic layer, etc.), such as a base layer, intermediate coating, top coating, layer, or any other suitable insulating layer formed around a conductor. In other embodiments, one or more additives can be incorporated into multiple insulating layers.

[0012] In some embodiments, the additives used to reduce the dielectric constant of the insulation may include one or more polycyclic aromatic hydrocarbons (“PAHs”) and / or partially or fully hydrogenated compounds of one or more polycyclic aromatic hydrocarbons. In some embodiments, the PAHs and / or partially or fully hydrogenated compounds of PAHs include, but are not limited to, polyphenyl (as defined below) and polybenzyl (as defined below). Non-limiting examples of suitable additives include, but are not limited to: fluorene, anthracene, triphenylene, tetraphenylene, pentaphenylene, phenanthrene, phenanthene, phenylene, biphenylene, chlorophenene, pyrene, perylene, succinate, succinate, pentadiene, indene, chamomile, heptaphenylene, indacene, acenaphthene, fluoranthene, acetylene, naphthobenzene, pleuadene, fentanyl, pentanylene, tetraphenylene, hexaphenylene, hexanthene, fentanyl, hexaphenylene, triphenylene, pyranethene, heptaphenylene, heptaphenylene, and their derivatives and / or their partially or fully hydrogenated compounds. In some embodiments, the additives may include, but are not limited to, dibenzyltoluene (“Dibenzyltoluene”, “DBT”) (CAS No.: 26898-17-9); monobenzyltoluene (“Monobenzyl toluene”, “MBT”) (CAS No.: 27776-01-8); Therminol® 75 manufactured and sold by Eastman Chemical Company, whose components include terphenyl (CAS No. 26140-60-3), phenanthrene (CAS No. 85-01-8), and tetraphenyl (CAS No. 29036-02-0); or Therminol® 66 manufactured and sold by Eastman Chemical Company, whose components include hydrogenated terphenyl (CAS No. 61788-32-7), partially hydrogenated tetraphenyl and higher polyphenylene (CAS No. 68956-74-1), and terphenyl (CAS No. 26140-60-3). In addition to the additives listed in the non-limiting examples, a variety of other suitable additives may be used, such as any suitable aryl component having a dielectric constant lower than that of the base material used to form the insulating layer.

[0013] For the purposes of this disclosure, the term “polyphenyl” refers to a polycyclic aromatic hydrocarbon comprising at least one phenyl group, such as biphenyl, triphenyl, tetraphenyl, etc. In other words, the “poly” in polyphenyl may represent diphenyl (2), triphenyl (3), tetraphenyl (4), hexaphenyl (6), octaphenyl (8) or higher. Examples of polyphenylene include, but are not limited to: 4-benzylbiphenyl (CAS No.: 613-42-3); terphenyl (CAS No.: 26140-60-3), p-terphenyl (CAS No.: 92-94-4), m-terphenyl (CAS No.: 92-06-8), o-terphenyl (CAS No.: 9984-15-1); 1,2,3-triphenylbenzene (CAS No.: 1165-14-6), 1,2,4-triphenylbenzene (CAS No.: 1165-53-3), 1,3,5-triphenylbenzene (CAS No.: 612-71-5); triphenylmethane (CAS No.: 519-73-3), (triphenylmethyl)benzene (CAS No.: 630-76-2), 1,1 1-Triphenylethane (CAS No.: 5271-39-6), 1,1,2-Triphenylethane (CAS No.: 1520-42-9), 1,1,3-Triphenylpentane (CAS No.: 19120-39-9); Triphenylene (CAS No.: 217-59-4); p-Tetraphenyl (CAS No.: 135-70-6), m-Tetraphenyl (CAS No.: 1166-18-3), Tetraphenylmethane (CAS No.: 630-76-2); p-Pentaphenyl (CAS No.: 3073-05-0), Pentaphenylbenzene (CAS No.: 18631-82-8), 1,2,3,4,5-Pentaphenyl-1,3-Cyclopentadiene (CAS No.: 2519-10-0).

[0014] For the purposes of this disclosure, the term “polybenzyl” refers to a polycyclic aromatic hydrocarbon comprising at least one benzyl group, such as bibenzyl, tribenzyl, tetrabenzyl, etc. In other words, the “poly” in polybenzyl may represent di(2), tri(3), tetra(4), or higher. Examples of polybenzyl include, but are not limited to: bibenzyl (CAS No.: 103-29-7), (E)-stilbene (CAS No.: 103-30-0), (Z)-stilbene (CAS No.: 645-49-8); 1,2-dibenzylbenzene (CAS No.: 792-68-7), 1,3-dibenzylbenzene (CAS No.: 15180-20-8), 1,4-dibenzylbenzene (CAS No.: 793-23-7); dibenzyltoluene (CAS No.: 26898-17-9), 2,3- Dibenzyltoluene (CAS No.: 115643-65-7), 2,4-dibenzyltoluene (CAS No.: 94871-33-7); Tribenzylmethane (CAS No.: 4742-05-5), 1,2,3-tribenzylbenzene (CAS No.: 143319-04-4), 1,2,4-tribenzylbenzene (CAS No.: 96068-48-3); 1,2,4,5-tetrabenzylbenzene (CAS No.: 1460-03-3); Tetrabenzylethylene (CAS No.: 19754-02-0).

[0015] In some embodiments, a single additive may be used to reduce the dielectric constant. In other embodiments, a combination of additives or a mixture of multiple additives may be used. If a combination of additives is incorporated, any suitable additive mixing ratio may be used. Furthermore, one or more additives may be selected based on various suitable properties desired in the various embodiments. For example, in some embodiments, at least one additive may have a boiling point at standard atmospheric pressure (760 mmHg) greater than the desired value, such as 280°C. As another example, in some embodiments, at least one additive may have a dielectric constant less than the desired value, such as 3.2, at 20°C to 150°C.

[0016] Additionally, any suitable loading factor of additives may be used as needed. In other words, any suitable weight percentage of additives may be incorporated into the material used to form the insulating layer. In some embodiments, the additive (or combination of additives) may comprise between about 1.0% (1.0%) and about 60% (60.0%) of the weight of the material used to form the insulating layer. For example, in various embodiments, the additive may comprise about 0.1%, 0.5%, 1.0%, 3.0%, 5.0%, 7.0%, 10.0%, 15.0%, 20.0%, 25.0%, 30.0%, 35.0%, 40.0%, 45.0%, 50.0%, 55.0%, or 60.0% of the weight of the material used to form the insulating layer, with the weight percentage included in the range between any two of the above values, or in the range defined by one of the above values ​​at the maximum end. Higher amounts of additives generally result in a lower dielectric constant of the resulting insulating layer.

[0017] Because one or more additives are incorporated into the material used to form one or more magnetic wire insulation layers, the dielectric constant of the insulation layer may be reduced or decreased. In some embodiments, one or more additives may be incompatible with the base insulation material before the insulation material cures, so that the additive(s) will not chemically react with the base insulation material. In other words, the additives may be dispersed in the base insulation material before curing. After the insulation material cures, at least a portion of the additive(s) may remain in the final insulation layer. Given that the additive(s) have a lower dielectric constant relative to the base insulation material, the presence of the additive(s) in the insulation layer helps to reduce the dielectric constant of the insulation layer. In some embodiments, a portion of the additive(s) may evaporate or ablate, resulting in voids within the cured insulation layer. For example, given the voids created by the evaporated additives, the insulation layer may resemble a foam layer or a porous layer. Voids may result in an insulation layer with a lower dielectric constant compared to an insulation layer without the one or more additives incorporated.

[0018] In some embodiments, the dielectric constant of an insulating layer formed with one or more additives for reducing the dielectric constant can be at least 0.3 lower than that of an insulating layer formed without one or more additives as described herein (i.e., an insulating layer formed using the same base polymer material but without the additives). In various embodiments, the dielectric constant can be at least 0.3, 0.5, 0.7, 0.9, or much lower. Additionally, a lower dielectric constant may contribute to improved electrical properties of the insulating layer. For example, the PDIV and / or dielectric strength of the insulating layer may be enhanced relative to an insulating layer formed without (one or more) additives. In some embodiments, the PDIV value of an insulating layer formed with one or more additives for reducing the dielectric constant at 25°C can be at least 5.0% higher than that of an insulating layer formed solely from the base insulating material. In various embodiments, the PDIV of an insulating layer formed with one or more additives at 25°C can be 5.0%, 10.0%, 15.0%, 20.0%, or a higher percentage than that of an insulating layer formed without additives.

[0019] Embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings, which illustrate certain embodiments of the present disclosure. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the disclosure thorough and complete, and to fully convey the scope of the invention to those skilled in the art. Throughout the text, the same reference numerals refer to the same elements.

[0020] Figures 1A to 1D The illustration shows a cross-sectional view of an example magnetic wire structure including a low-dielectric-constant insulating structure. Specifically, Figure 1A The illustration shows a cross-sectional view of an example magnetic wire having a circular or annular cross-sectional shape, wherein a single insulating layer 110 (which may include sublayers) is formed around a conductor 105. Figure 1B Another example magnetic wire 120 with a circular cross-sectional shape is illustrated. Magnetic wire 120 may include a conductor 125 and multiple insulating layers 130, 135 formed around the conductor 125. In other words, magnetic wire 120 may include an undercoat insulating layer 130 formed around the conductor 125, and at least one additional layer (e.g., a topcoat 135) of an insulating structure formed around the undercoat 130. Although Figure 1B The diagram illustrates a single additional layer 135 of the insulating structure, but any number of insulating layers can be formed around the base layer 130. For example, the magnetic wire 120 may include a base layer insulating layer, an intermediate layer insulating layer, and a top layer insulating layer. In other embodiments, more than three insulating layers may be formed around the magnetic wire.

[0021] Figure 1CAn example magnetic wire 150 with a rectangular cross-sectional shape is illustrated, wherein a single insulating layer 160 (which may include sublayers) is formed around a conductor 155. Figure 1D Another example magnetic wire 170 with a rectangular cross-sectional shape is illustrated. (Compared to...) Figure 1B Similar to magnetic line 120 in the middle, Figure 1D The magnetic wire 170 may include a conductor 175 and a first layer 180 and a second layer 185 of insulating layers formed around the conductor 175. In other words, the magnetic wire 170 may include a base layer insulating layer 180 formed around the conductor 175, and at least one additional layer (e.g., a top layer 185) of an insulating structure formed around the base layer 180. Any number of additional layers of insulating structure may be used as needed. For example, the magnetic wire 170 may include a base layer insulating layer, an intermediate layer insulating layer, and a top layer insulating layer. In other embodiments, more than three insulating layers may be formed around the magnetic wire.

[0022] Figures 1A to 1D The insulating structures of the example magnetic wire structures 100, 120, 150, and 170 illustrated in the figures can be formed from a variety of suitable materials and / or combinations of materials. For example, the insulating layer can be formed from thermosetting polymer materials, thermoplastic polymer materials, and / or other suitable materials (e.g., semiconductor materials, inorganic materials including ceramics, glass, etc.). In fact, as described in more detail below, the magnetic wires can be formed using a variety of suitable insulating systems. According to one aspect of this disclosure, at least one insulating layer is formed using one or more additives that reduce or decrease the dielectric constant of the insulating layer.

[0023] The following will describe it in more detail. Figure 1D Each layer or component of the 170 magnetic wires. Figures 1A to 1C The example magnetic lines 100, 120, and 150 in the reference may include references. Figure 1D The described layers or components are similar to those described above. In fact, magnetic wires can be formed with a variety of suitable cross-sectional shapes and insulation structures according to the requirements of various embodiments, provided that at least one layer of the insulation structure includes one or more additives that function to reduce copper ion migration.

[0024] refer to Figure 1DConductor 175 can be formed from a variety of suitable materials and / or combinations thereof. For example, conductor 175 can be formed from copper, annealed copper, oxygen-free copper, silver-plated copper, nickel-plated copper, tin-plated copper, lead-plated copper, molybdenum-plated copper, tungsten-plated copper, copper-clad aluminum (“copper clad aluminum”, “CCA”), conductive alloys, copper-coated materials, or any other suitable conductive material (including copper, aluminum, or any other suitable conductive material or combination of conductive materials). Additionally, conductor 175 can be formed from any suitable size and / or cross-sectional shape. As shown, conductor 175 can have a rectangular cross-sectional shape. In other embodiments, for example… Figure 1A and Figure 1C In the illustrated embodiments, the conductor may have an annular or circular cross-sectional shape. In other embodiments, the conductor may be square, elliptical or oval, hexagonal, or any other suitable cross-sectional shape. Additionally, for certain cross-sectional shapes (such as the rectangular shape illustrated), the conductor may have rounded corners, sharp corners, smooth corners, curved corners, beveled corners, truncated corners, or other angles as needed. For example, a shaped rectangular line may have rounded corners.

[0025] Conductor 175 can also be formed from any suitable dimensions (e.g., any suitable gauge, diameter, height, width, cross-sectional area, etc.). As a non-limiting example, the long side of a rectangular conductor 175 may be between approximately 0.020 inches (508 μm) and approximately 0.750 inches (19050 μm), and the short side may be between approximately 0.020 inches (508 μm) and approximately 0.400 inches (10160 μm). Example square conductors may have sides between approximately 0.020 inches (508 μm) and approximately 0.500 inches (12700 μm). Example circular conductors may have diameters between approximately 0.010 inches (254 μm) and approximately 0.500 inches (12700 μm). Other suitable dimensions may be utilized as needed.

[0026] Various suitable methods and / or techniques can be used to form, produce, or otherwise provide the conductor 175. In some embodiments, the conductor 175 can be formed by drawing input material (e.g., a large conductor, wire blank, etc.) through one or more dies to reduce the size of the input material to the desired dimensions. As needed, one or more flatteners and / or rollers can be used to modify the cross-sectional shape of the input material before and / or after drawing it through any die. In some embodiments, the conductor 175 can be formed simultaneously with the application of part or all of the insulation system. In other words, conductor formation and the application of insulation material can be performed concurrently. In other embodiments, the conductor 175, having the desired dimensions, can be pre-made or obtained from an external source, and then the insulation material is applied via subsequent processes.

[0027] Continue to refer to Figure 1D Multiple insulating layers 180, 185 are depicted as forming around conductor 175. In other embodiments, such as Figure 1A and Figure 1C As shown, a single-layer insulation layer (e.g., a single-layer extruded thermoplastic insulation layer, a single-coat enamel insulation layer, etc.). If multiple insulation layers 180°, 185° are formed around the conductor, any suitable number of insulation layers can be formed. For example, as... Figure 1D As shown, a first base coating insulating layer 180 and a second top coating insulating layer 185 can be formed. As another example, three insulating layers can be formed, such as a base coating, an intermediate coating, and a top coating. Other embodiments may include more than three layers.

[0028] Additionally, the insulating layers 180, 185 can be formed from a variety of suitable materials. For example, one or more insulating layers can be formed from a thermosetting polymer material as an enamel layer. As another example, one or more insulating layers can be formed from an extruded thermoplastic material. Additionally, it should be understood that a given insulating layer may include one or more sublayers. For example, an enamel layer can be formed from any number of sublayers, which are formed sequentially until the desired build-up thickness is achieved. As another example, a thermoplastic layer can be formed from sequentially extruded layers. Example thermosetting and thermoplastic insulating layers will be described in more detail below.

[0029] In some embodiments where the magnetic wire 170 includes multiple insulating layers 180, 185, each layer may be formed from the same polymer material. In other embodiments, at least two of the insulating layers (e.g., layer 180, layer 185, etc.) may be formed from different materials or materials with different molecular structures and / or compositions. For example, two enamel layers may be formed from different thermosetting polymer materials. As another example, two enamel layers may be formed from the same base polymer material; however, these two enamel layers may include different fillers and / or additives. As yet another example, two thermoplastic layers may be formed from different materials and / or different mixtures of materials. As yet another example, the first insulating layer may be formed from a thermosetting polymer material, and the second insulating layer may be formed from a thermoplastic material. Various suitable fillers and / or additives may be selectively incorporated into any insulating layer. Additionally, according to one aspect of this disclosure, additives that reduce or lower the dielectric constant may be used with any number of insulating layers. For example, additives that lower the dielectric constant may be used when forming each layer or a subset of layers.

[0030] As described above, in some embodiments, the magnetic wire 170 may comprise one or more enamel insulation layers formed from a thermosetting polymer material. The enamel layer is typically formed by applying a polymer varnish to the conductor 175 and then baking the conductor 175 in a suitable enamel furnace or furnace. The polymer varnish typically comprises a polymer solid material suspended in one or more solvents, wherein the polymer solid may be thermosetting and / or thermoplastic and / or a combination thereof with fillers and additives. After the varnish is applied (on the conductor or underlayer insulation), the solvent is removed by evaporation, heating, and / or radiation, leaving a solid polymer enamel layer. Multiple enamel sublayers may be applied to the conductor 175 as needed to form the enamel insulation layer. For example, a first enamel sublayer may be applied to allow the conductor 175 to pass through an enamel furnace or other suitable curing and / or solidification apparatus. A second enamel sublayer may then be applied to allow the conductor 175 to pass through a curing apparatus (or a separate curing apparatus). This process may be repeated until the desired number of enamel coatings are applied and / or until the desired enamel thickness or buildup is achieved. As needed, an enamel furnace can be configured to allow the wire to pass through the furnace more than 170 times. In addition to or as an alternative to an enamel furnace, other curing equipment can be used, including but not limited to infrared systems, ultraviolet systems, and / or electron beam systems. In various embodiments, any number of enamel layers can be formed. Additionally, each enamel layer and / or the entire stack of enamel layers can have any desired thickness, such as approximately 0.0002, 0.0005, 0.007, 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.010, 0.012, 0.015, 0.017, or 0.020 inches, where the thickness is within the range of any two of the aforementioned values, or within the range defined by one of the aforementioned values ​​at either the minimum or maximum end.

[0031] Various types of polymeric materials can be used to form the enamel layer as needed. Suitable material examples include, but are not limited to: polyimide (PI), polyamideimide (PAI), amideimide, polyurethane, polyester, THEIC polyester, polyesterimide, polysulfone, polyphenylsulfone, polysulfide, polyphenylene sulfide, polyetherimide, polyamide, polyamide-ester-imide, polyimide sulfone, polybenzimidazole (PBI), poly(oxyphenylene benzimidazole) (OPBI), poly(benzimidazole-imide) (PBII), polybenzimidzopyrrolone (PBIP), polyketones, phenolic polymers, epoxy polymers, silicone-containing polyimides, silicone polymers, fluorinated polyimides, fluorinated polymers, and suitable combinations of materials. In some embodiments, if multiple enamel layers are formed, each enamel layer can be formed from the same polymer material or base polymer material. For example, multiple PI enamel layers may be formed. As another example, the first enamel layer may include filled PI, while the second enamel layer may include unfilled PI. In other embodiments, at least two enamel layers may be formed from or comprise different polymer materials. For example, the first enamel layer may include PI, while the second enamel layer may include PAI. It should be understood that any suitable enamel layer or combination of enamel layers can be incorporated into the magnetic wire insulation system.

[0032] Depending on the requirements, various commonly used additives (other than those described herein for reducing dielectric constant) can be combined with polymeric materials used to form the enamel layer. Examples of such additives include crosslinking agents, curing accelerators, heat stabilizers, antioxidants, UV stabilizers, plasticizers, antistatic agents, antiblocking agents, foaming agents, lubricants, process modifiers and / or processing aids, rheology modifiers (e.g., diluents, thickeners, etc.), defoamers (e.g., silicone-based, fluorinated, or polymeric defoamers), leveling agents for reducing surface tension, compatibilizers, coupling agents or surface treatment agents, adhesion promoters, flame retardants (e.g., phosphorus-based flame retardants, nitrogen-based flame retardants, metal salt flame retardants, etc.), reinforcing modifiers (e.g., fibers, fillers, minerals, etc.), spherical, fibrous, or irregularly shaped inorganic nonmetallic fillers, organic fillers, pigments, dyes and / or colorants (e.g., phthalocyanine blue, phthalocyanine green, iodine green, diazoxide yellow, crystal violet, titanium dioxide, carbon black, naphthalene black, etc.), antibacterial agents, deodorizers and / or water absorbents.

[0033] Examples of crosslinking agents include, but are not limited to: isocyanate compounds, blocked isocyanate compounds, cyanate compounds, aziridine compounds, compounds containing anhydride groups, compounds containing carboxyl groups, compounds containing carbodiimide groups, benzoxazine compounds, maleimide compounds, citrileimide compounds, norbornene dicarboximide compounds, allyl norbornene dicarboximide compounds, vinyl ether compounds, vinyl benzyl ether resins, thiols, melamine compounds, cucurbitamine compounds, amino resins, phenolic resins, alkyd resins, acrylic resins, unsaturated polyester resins, diallyl phthalate resins, silicone resins, xylene resins, furan resins, ketone resins, triallyl cyanurate resins, resins containing tris(2-hydroxyethyl) isocyanurate, resins containing triallyl trimellitate, dicyclopentadiene resins, and thermosetting resins obtained by trimerization of aromatic dicyandiamides.

[0034] Examples of curing accelerators include, but are not limited to, imidazole derivatives, citrulline (e.g., acetylguanidine, benzomelamine, etc.), polyamines (e.g., diaminodiphenylmethane, m-phenylenediamine, m-phenylenediamine, diaminodiphenyl sulfone, dicyandiamide, urea, urea derivatives, melamine, polybasic hydrazides, etc.), organic acid salts and / or their epoxy adducts, boron trifluoride amine complexes, triazine derivatives (e.g., ethylenediaminopyridine, 2,4-diaminopyridine, 2,4-diamino-6-dimethylpyridine, etc.), tertiary amines (e.g., trimethylamine, triethanolamine, N,N-dimethyloctylamine, N-benzyldimethylamine, etc.). Pyridine, N-methylmorpholine, hexa(N-methyl)melamine, etc.), 2,4,6-tris(dimethylaminophenol), tetramethylguanidine, 1,8-diazabicyclo[5,4,0]-7-undecene (“DBU”), 1,5-diazabicyclo[4,3,0]-5-nonene (“DBN”), etc.), organic acid salts and / or their tetraphenylborate esters, polyvinylphenol, polyvinylphenol bromide, organophosphorus (e.g., tributylphosphine, triphenylphosphine, tri(2-cyanoethyl)phosphine, etc.) and quaternary phosphonium salts (e.g., tri-n-butyl(2,5-dihydroxyphenyl)phosphonium bromide, hexadecyltributylphosphonium, etc.).

[0035] In some embodiments, one or more other filler materials may be incorporated into the enamel layer as needed. Examples of suitable filler materials include, but are not limited to: inorganic materials, such as metals, transition metals, lanthanides, actinides, carbon nanotubes, boron nitride, metal oxides, and / or hydrated oxides of suitable materials, such as aluminum, tin, boron, germanium, gallium, lead, silicon, titanium, chromium, zinc, yttrium, vanadium, zirconium, nickel, etc. (e.g., titanium dioxide, silicon dioxide, or silicon dioxide, etc.); suitable organic materials, such as polyaniline, polyacetylene, polyphenylene oxide, polypyrrole, other conductive particles; and / or any combination of suitable materials (e.g., mixtures or blends of metal oxides, etc.). In some embodiments, the filler material (one or more) may enhance corona resistance and / or one or more thermal properties (e.g., temperature resistance, cut resistance, abrasion resistance, thermal shock resistance, etc.). The filler particles can have any suitable size, and any suitable mixing ratio or filler ratio can be used between the filler and the polymer material (e.g., filler ratios of approximately 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%, or filler ratios within a range of these values). Additionally, if the filler comprises a mixture of different materials, any suitable mixing ratio can be used between the components of the filler.

[0036] In addition to, or as an alternative to, one or more enamel layers, the magnetic wire 170 may be formed of one or more thermoplastic polymer insulating layers, such as one or more extruded polymer insulating layers. The thermoplastic insulating layers are typically formed by molten extruding a thermoplastic polymer material around the conductor 175 (and, if present, any underlying insulating layer). In various embodiments, any number of thermoplastic insulating layers may be formed. Additionally, each thermoplastic polymer insulating layer may have a desired thickness, for example, between approximately 15 micrometers and approximately 200 micrometers. In various embodiments, the thickness of the thermoplastic insulation layer may be approximately 15, 20, 25, 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500, 525, 550, 575, or 600 micrometers, and the thickness is included in the range between any two of the above values, or the thickness is included in the range defined by one of the above values ​​at the minimum or maximum end.

[0037] A variety of suitable materials and / or combinations of materials can be used to form extruded thermoplastic insulation structures. Suitable material examples include, but are not limited to: polyetheretherketone (“PEEK”), polyetherketoneketone (“PEKK”), polyetheretherketoneketone (“PEEKK”), polyetherketoneketone (“PEK”), polyetherketone (“PAEK”), other suitable polymers and / or copolymers thereof comprising at least one ketone group, polyetherimide (“PEI”) (e.g., Ultem® sold by SABIC Global Technologies), polyphenylene sulfone (“PPSU”) (e.g., Radel® sold by Solvay Specialty Polymers USA), polyethersulfone (“PESU”), any suitable aromatic polysulfone, polyphenylene sulfide (“PPS”), polybenzimidazole (“PBI”), polycarbonate, one or more polyesters (e.g., polyethylene terephthalate (“PET”), etc.), one or more copolyesters, polyamides, aromatic polyamides, thermoplastic polyimide (“TPI”), one or more acrylic polymer materials, one or more fluoropolymers, polystyrene and / or various copolymers of multiple materials. In some embodiments, the thermoplastic insulating layer may be formed from a mixture of two or more polymer materials.

[0038] As needed, various commonly used additives (except for those that reduce dielectric constant as described herein) can be incorporated into the thermoplastic insulation layer, including but not limited to crosslinking agents, curing accelerators, heat stabilizers, antioxidants, UV stabilizers, plasticizers, antistatic agents, antiblocking agents, foaming agents, lubricants, process modifiers and / or processing aids, rheology modifiers (e.g., diluents, thickeners, etc.), leveling agents, compatibilizers, reinforcing modifiers (e.g., fibers, fillers, minerals, etc.), flame retardants, pigments, dyes, colorants, antibacterial agents, deodorizers and / or water absorbents.

[0039] In some embodiments, one or more other filler materials may be incorporated into the thermoplastic layer as needed. Examples of suitable filler materials include, but are not limited to: inorganic materials, such as metals, transition metals, lanthanides, actinides, carbon nanotubes, boron nitride, metal oxides, and / or hydrated oxides of suitable materials, such as aluminum, tin, boron, germanium, gallium, lead, silicon, titanium, chromium, zinc, yttrium, vanadium, zirconium, nickel, etc. (e.g., titanium dioxide, silicon dioxide, etc.); suitable organic materials, such as polyaniline, polyacetylene, polyphenylene oxide, polypyrrole, other conductive particles; and / or any combination of suitable materials (e.g., metal oxide mixtures, etc.). In some embodiments, the filler material (one or more) may enhance corona resistance and / or one or more thermal properties (e.g., temperature resistance, cut resistance, thermal shock resistance, etc.). The filler material particles may have any suitable size, and any suitable mixing ratio or filler percentage may be used between the filler material and the polymer material (e.g., filler percentages of approximately 5%, 10%, 15%, 20%, or 25%, or filler percentages within any range of these values). Additionally, if the packing comprises a mixture of different materials, any suitable mixing ratio can be used between the components of the packing.

[0040] In some embodiments, a multilayer thermoplastic insulation layer may be formed around conductor 175. In some embodiments, the multilayer thermoplastic layers may be formed simultaneously via a single co-extrusion process. In other embodiments, multiple separate extrusion steps may be used to form a continuous layer. Additionally, in some embodiments, if a multilayer thermoplastic insulation layer is formed, each layer may be formed from the same polymer material or base polymer material. For example, a multilayer PEEK insulation layer may be formed. As another example, the first PEEK layer may include filled PEEK, while the second layer may include unfilled PEEK. In other embodiments, at least two thermoplastic insulation layers may be formed from different polymer materials or may include different polymer materials. As a non-limiting example, the first layer may include PPSU, while the second layer may include PEEK. It should be understood that any suitable thermoplastic layer or combination of thermoplastic layers may be incorporated into the magnetic wire insulation system. Additionally, it is understood that in some embodiments, a layer or multiple layers of thermoplastic layers may be formed over one or more enamel layers.

[0041] If the thermoplastic layer is formed from a polymeric material (mixture), the two or more components of the polymeric material can be mixed together at any suitable mixing ratio or proportion in the mixture. For example, the weight percentage of each component in the polymeric mixture may be between about 1.0% and about 99%. In some embodiments, each component material incorporated in the mixture (e.g., a first component material, a second component material, etc.) may account for about 5%, 10%, 15%, 20%, 25%, 30%, 40%, 45%, 50%, 60%, 70%, 75%, 80%, 90%, or 95% of the weight of the mixture, or the weight percentage may be included in a range between any two of the above values ​​(e.g., between about 5% and 95%, between about 10% and 90%, etc.), or the weight percentage may be included in a range defined by one of the above values ​​at the minimum or maximum end (e.g., at least 5%, at least 10%, no more than 95%, no more than 90%, etc.). The component materials and their relative amounts incorporated into the mixture can be selected based on a variety of suitable factors, including but not limited to material cost, processing characteristics, required dielectric breakdown voltage (DBV), required partial discharge inception voltage (PDIV), required cut size, required thermal aging properties, required temperature rating, required crystallinity, required flexibility, required adhesion, etc.

[0042] Depending on the requirements, other types of insulating layers may be used in addition to one or more enamel layers and / or one or more thermoplastic layers. For example, the magnetic wire 170 may incorporate one or more suitable packaging tapes or adhesive tapes, such as polymer tape wrapped around the conductor 175 and any underlying insulating layer. In other embodiments, the insulating system of the magnetic wire 170 may include one or more layers of semiconductor material. The conductivity of the semiconductor layer may be intermediate between that of the conductor 175 and the insulator, and using one or more semiconductor layers helps to equalize or “smooth” non-uniform electric, magnetic, and / or electromagnetic fields that may stress the magnetic wire insulation layer.

[0043] The insulating materials incorporated in the magnetic wire 170 can be selected to achieve a variety of suitable properties and / or characteristics. For example, polymeric materials and / or various combinations of polymeric materials can be selected to achieve the desired thermal rating (or heat class), thermal index, and / or thermal durability. Thermal ratings are typically established by industry standards organizations (e.g., the National Electrical Manufacturers Association, the International Electrotechnical Commission, UL, etc.) and specify the maximum permissible temperature for the insulating material and / or magnetic wire. Example thermal ratings include, for example, 150°C, 180°C, 200°C, 220°C, 240°C, 250°C, 260°C, 270°C, and 280°C. The thermal index is typically defined as a numerical value in degrees Celsius and is used to compare the characteristics of electrical insulation materials as a function of temperature over time. It can be obtained by extrapolating a life versus temperature Arrhenius plot to a specified time (typically 20,000 hours). As an example, the difference between heat rating and heat index is that a material's heat index may be 230°C; however, the material's heat rating is 220°C because it does not meet the requirement of the next available heat rating of 240°C. As another example, polymer materials can be selected based on their physical properties (e.g., whether the thermoplastic is amorphous, crystalline, semi-crystalline, etc.), shrinkage characteristics, resistance to certain fluids (e.g., transmission fluids), partial discharge initiation voltage, dielectric strength, and / or any other suitable properties.

[0044] In some embodiments, the insulation system formed on the magnetic wire 170 may have a variety of suitable electrical performance parameters, such as various suitable PDIV values ​​and / or dielectric strength or breakdown strength values. In some embodiments, the insulation system may provide a PDIV value of at least about 800, 900, 1000, 1100, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300 or 2400 volts at 25°C, or provide a PDIV value that falls within the range of any two of the above values. Similarly, in some embodiments, the insulation system may provide a dielectric strength value of at least approximately 10,000, 11,000, 12,000, 12,500, 13,000, 13,500, 14,000, 14,500, 15,000, 15,500, 16,000, 16,500, 17,000, 17,500, 18,000, 18,500, 19,000, 20,000, 20,500, or 21,000 volts (e.g., dielectric strength values ​​measured by suitable industry standard tests such as pulse cell tests or foil tests), or a dielectric strength value that falls within a range between any two of the above values. Other suitable performance parameters may be set and / or implemented as needed. As described in more detail below, the PDIV value and / or dielectric strength value of an insulation system can be improved by using one or more additives that reduce the dielectric constant to form the insulating layer.

[0045] Additionally, in embodiments incorporating multiple insulating layers, any suitable thickness ratio of one or more layers can be used between the layers. In an example using an insulation system with two insulating layers, the first layer can comprise any suitable percentage of the total thickness of the combined insulation layers (e.g., 1% to 99%, at least 50%, etc.), and the second layer can comprise any suitable percentage of the total thickness. The thickness ratio of the insulating layers can be selected as needed to meet various suitable design parameters. For example, the desired electrical performance can be weighed against the cost of the materials used to form the insulating layers.

[0046] According to one aspect of this disclosure, regardless of the type of insulation system formed on the magnetic wire, one or more additives that reduce or decrease the dielectric constant can be used in the formation and / or incorporation into any desired number of insulation layers. For example, one or more additives can be used when forming a single insulation layer (e.g., layer 180, layer 185, etc.). As other examples, one or more additives can be used when forming multiple insulation layers 180, 185, a subset of insulation layers, or all insulation layers.

[0047] Depending on the requirements of various embodiments, a variety of different additives and / or combinations of additives may be used to reduce or lower the dielectric constant. In some embodiments, additives for reducing the dielectric constant of the insulation may include one or more polycyclic aromatic hydrocarbons (“PAHs”) and / or partially or fully hydrogenated compounds of one or more PAHs. In some embodiments, PAHs and / or partially or fully hydrogenated compounds of PAHs include, but are not limited to, polyphenyl (as defined above) and polybenzyl (as defined above). Non-limiting examples of suitable additives include, but are not limited to, fluorene, anthracene, triphenylbenzene, tetraphenylbenzene, pentaphenylbenzene, phenanthrene, phenanthracene, phenylene, biphenylene, chlorophenene, pyrene, perylene, succinate, succinate, pentadiene, indene, chamomile, heptaphenyl, indole, acenaphthene, fluoranthene, acetanthene, naphthobenzene, purulene, fentanyl, pentophenone, tetraphenylbenzene, hexane, fentanyl, hexane, hexanebenzene, trinaphthalene, pyranethracene, heptaphenone, heptaphenyl, and their derivatives, and / or their partially or fully hydrogenated compounds. In some embodiments, the additives may include, but are not limited to, dibenzyltoluene (“DBT”) (CAS No.: 26898-17-9); monobenzyltoluene (“MBT”) (CAS No.: 27776-01-8); Therminol® 75 manufactured and sold by Eastman Chemical Company, comprising terphenyl (CAS No. 26140-60-3), phenanthrene (CAS No. 85-01-8), and tetraphenyl (CAS No. 29036-02-0); or Therminol® 66 manufactured and sold by Eastman Chemical Company, comprising hydrogenated terphenyl (CAS No. 61788-32-7), partially hydrogenated tetraphenyl and higher polyphenylene (CAS No. 68956-74-1) and terphenyl (CAS No. 26140-60-3). In addition to the additives listed in the non-limiting examples, a variety of other suitable additives may be used, such as any suitable aryl component having a dielectric constant lower than that of the base material used to form the insulating layer.

[0048] In some embodiments, at least one additive that reduces the dielectric constant may have a boiling point greater than 250°C at standard atmospheric pressure (760 mmHg). For example, at least one additive may have a boiling point greater than 280°C at standard atmospheric pressure. In some embodiments, the selection of at least one additive may be based at least in part on the curing or bonding temperature (e.g., extrusion temperature, etc.) of the polymeric insulating material incorporating the additive. For example, the additive may be selected for use with a thermosetting polymeric material used to form an enamel layer, the curing temperature of which is higher than the boiling point of the additive (e.g., a curing temperature of at least 250°C or at least 280°C). As another example, the additive may be selected for use with a thermoplastic polymeric material, the bonding temperature of which is equal to or higher than the boiling point of the additive. In some embodiments, the dielectric constant of at least one additive may be less than 3.2 at 20°C to 150°C, as needed.

[0049] In some embodiments, a single additive that reduces the dielectric constant may be used. In other embodiments, a combination of additives or a mixture or blend of multiple additives may be used. For example, any two or more additives discussed above or in Appendix A may be mixed or fused together. If a combination of additives is incorporated, any suitable additive mixing ratio may be used. For example, each additive may constitute about 0.3%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, 95%, or 95% of the additive mixture, or the percentage may be included within the range of any two of the above values.

[0050] Additionally, any suitable amount of additive may be used as needed. In other words, any suitable weight percentage of additive may be incorporated into the material used to form the insulating layer (e.g., the polymeric resin used to form the enamel layer, etc.). In some embodiments, the additive (or combination of additives) may account for between about 1.0 percent (1.0%) and about 60 percent (60.0%) of the weight of the material used to form the insulating layer. For example, (one or more) additives may account for between about 1 percent (1.0%) and about 20 percent (20.0%) of the weight of the material used to form the insulating layer. In various embodiments, one or more additives may comprise about 0.1, 0.5, 1.0, 3.0, 5.0, 7.0, 10.0, 15.0, 20.0, 25.0, 30.0, 35.0, 40.0, 45.0, 50.0, 55.0, or 60.0% of the weight of the material used to form the insulating layer, with the weight percentage included in the range between any two of the above values, or included in the range defined by one of the above values ​​at the maximum end. Higher amounts of additives generally result in a lower dielectric constant of the resulting insulating layer.

[0051] Various suitable methods or techniques can be used as needed to incorporate one or more additives into an insulating material to reduce the dielectric constant of the insulating layer. As an example, for an enamel insulation layer (e.g., an enamel layer formed from a thermosetting polymer material such as PI, PAI, or PBI), one or more additives can be mixed or fused into a varnish or a solvent-containing solution that also includes the polymer solids. The varnish can then be applied to the magnetic wire 170 and subsequently cured. Similarly, one or more additives can be mixed or fused into a paste and then applied to the magnetic wire 170 in a relatively low-solvent form and cured, or dissolved in a solution containing a higher solvent, and then the solution is applied to the magnetic wire and cured. Regardless of how the additive(s) are incorporated into the varnish or paste, the additive(s) may be dispersed in the varnish when it is applied to the magnetic wire. When the varnish is cured after being applied to the magnetic wire, the solvent may evaporate to form a solid enamel layer.

[0052] In some embodiments, after curing, at least a portion of the dielectric-reducing additive(s) will remain in the final insulating layer. The presence of additive(s) in the final insulating layer with a dielectric constant lower than that of the base polymer material will result in an insulating layer having a lower dielectric constant compared to an insulating layer formed without additive(s). In some embodiments, during curing, a portion of the dielectric-reducing additive may evaporate or ablate. For example, evaporation may occur because the curing temperature of the polymer insulating structure is higher than the boiling point of the additive. Therefore, voids may appear in the cured insulating layer where previously dispersed additives were located. In some embodiments, given the presence of voids, the cured insulating layer may be considered to have the characteristics of a foam layer, a partially foam layer, or a porous layer. The voids formed within the insulating layer may result in the insulating layer having a lower dielectric constant compared to an insulating layer formed without additive(s).

[0053] As another example, for an insulating layer formed from a thermoplastic polymer material (e.g., PEEK, etc.), one or more additives that reduce the dielectric constant can be incorporated into or dispersed in the base polymer material prior to extrusion. For example, one or more additives can be added, mixed, or fused into the polymer-based material in a suitable thermoplastic compounding apparatus (e.g., a single-screw extruder, a twin-screw extruder, or a Brabender mixer). The polymer material containing (one or more) additives can then be extruded onto magnetic wire 170 to form a thermoplastic insulating layer. In some embodiments, the extrusion temperature or compounding temperature can be higher than the boiling point of (one or more) additives. However, due to the pressure within the extrusion apparatus, the position of the additives in the extruded material may remain unchanged. In some embodiments, once the additives are coated onto the magnetic wire and exposed to ambient conditions, at least a portion of (one or more) additives will remain in the final insulating layer. The presence of (one or more) additives in the final insulating layer results in an insulating layer having a lower dielectric constant than an insulating layer formed without (one or more) additives. In some embodiments, once the additives are coated onto the magnetic wires and exposed to environmental conditions, a portion of the additive(s) may evaporate from the extruded polymer material, resulting in voids in the extruded insulating layer. In some embodiments, given the presence of voids, the extruded insulating layer may have the characteristics of a foam layer, a partially foam layer, or a porous layer. The voids formed within the insulating layer may result in the insulating layer having a lower dielectric constant compared to an insulating layer formed without the additive(s).

[0054] In some embodiments, for both enamel and thermoplastic insulating layers, it is understood that at least a portion of the dielectric-reducing additive will remain as a residue in the final insulating layer. Any suitable amount of additive may evaporate, and any suitable residue may remain in the finally cured insulating layer. In some embodiments, the amount of desired additive evaporation may be controlled at least in part by one or more process parameters under which the insulating layer is formed and / or cured. In some embodiments, approximately six percent (6%) to forty percent (40%) of the dielectric-reducing additive incorporated into the material used to form the insulating layer may remain as a residue in the final insulating layer.

[0055] Because one or more additives are incorporated into one or more materials used to form one or more magnetic wire insulation layers, the dielectric constant of the insulation layer may be reduced or decreased. For example, the presence of residual additives in the final insulation layer and / or voids generated in the final insulation layer may result in a lower dielectric constant of the insulation layer relative to a layer that does not contain one or more additives or contains one or more additives during formation. In some embodiments, at 25°C and 1 kHz, the dielectric constant of an insulation layer formed from one or more dielectric-reducing additives may be at least 0.3 lower than the dielectric constant of an insulation layer (i.e., a control polymer or control layer) formed without the use of one or more additives described herein. In various embodiments, the dielectric constant may be at least 0.3, 0.5, 0.7, 0.9, or a greater amount.

[0056] Additionally, a lower dielectric constant may contribute to improved electrical properties of the insulating layer. For example, the partial discharge initiation voltage (“PDIV”) and / or dielectric strength of the insulating layer may be enhanced compared to an insulating layer formed without (one or more) additives. In some embodiments, the PDIV value of an insulating layer formed from one or more dielectric-reducing additives at 25°C may be at least 5.0% higher than that of an insulating layer formed solely from a base insulating material (i.e., without dielectric-reducing additives). In various embodiments, the PDIV of an insulating layer formed from one or more additives at 25°C may be 5.0%, 10.0%, 15.0%, 20.0%, or a higher percentage than that of an insulating layer formed without additives (i.e., a control polymer or control layer).

[0057] The above references Figures 1A to 1DThe magnetic wires 100, 120, 150, and 170 described are provided by way of example only. In various embodiments, the illustrated magnetic wires 100, 120, 150, and 170 can be replaced as needed. For example, insulating layers with a different number of insulating layers than those shown in the illustrations can be used. As another example, the cross-sectional shape of the magnetic wires and / or one or more insulating layers can be varied. In fact, this disclosure contemplates a wide variety of suitable magnetic wire structures.

[0058] Figures 2A to 2B Schematic diagrams 200 and 250 depict insulated magnetic wires, incorporating additives to reduce the dielectric constant of the insulation layer. Illustrations 200 and 250 depict cross-sectional representations of an example conductor 205 coated with a material suitable for use with magnetic wires (e.g.,...). Figures 1A to 1D The insulating material for any magnetic wires (100, 120, 150, 170) shown. Specifically, Figure 2A Illustration 200 depicts a conductor 205 after it has been coated with an insulating material but before the insulating material has been cured. Figure 2B Illustration 250 depicts conductor 205 after the insulating material has been cured to form a solid polymer insulating layer. Each of illustrations 200 and 250 will be described in more detail below.

[0059] First go to Figure 2A Insulating material 210 can be coated onto the conductor, and one or more dielectric-reducing additives 215 can be distributed within the coated insulating material 210. As described in more detail above, various types of insulating materials 210 can be coated onto the conductor using any suitable technique. In some example embodiments, a varnish containing a polymeric material (e.g., a thermosetting polymeric material, etc.) and one or more dielectric-reducing additives suspended in a solvent can be coated onto the conductor 205. For example, a varnish containing polyimide (“PI”) and one or more additives can be coated. In other example embodiments, a thermoplastic polymeric material containing one or more additives can be extruded or otherwise coated onto the conductor 205. For example, a PEEK material containing one or more additives can be extruded onto the conductor 205. Additionally, in various embodiments, any suitable dielectric-reducing additives can be incorporated into the insulating material as needed, such as those referenced above. Figure 1D Any additives discussed.

[0060] Now go to Figure 2BAfter the insulating material 210 is applied to the conductor 205, the insulating material 210 can be cured to form a solid polymer insulating layer. For example, varnish can be cured in a suitable enamel furnace or via any other suitable technique to form an enamel layer. In some embodiments, during the curing process, a portion of the dielectric constant-reducing additive 215 may evaporate or burn off. Therefore, voids 260 may form within the enamel layer. As another example, in some embodiments, once the thermoplastic polymer material is extruded onto the conductor 205 and exposed to ambient conditions, a portion of the dielectric constant-reducing additive 215 may evaporate from the extruded insulating layer before the layer cools and / or fully cures. Therefore, voids 260 may form within the extruded layer. As described in more detail above, these voids 260 may result in an insulating layer (e.g., an enamel layer, an extruded layer, etc.) having a lower dielectric constant than an insulating layer formed without the additives described herein. Furthermore, as Figure 2B As shown, in some embodiments, at least a portion of the additive 215 may remain as a residual additive in the cured insulation layer.

[0061] Example

[0062] The following examples are intended to be illustrative and not limiting, and represent specific embodiments of the invention. Wire samples with enamel insulation are prepared using PAI, PI, and PBI enamels. PAI is prepared by reacting trimellitic anhydride (“TMA”) with methylene diphenyl 4,4'-diisocyanate (MDI) in an N-methyl-2-pyrrolidone (“NMP”) solvent. Additionally, both formulated PAI samples (e.g., “first PAI” and “second PAI”) have a solid content between about 36.5% and about 40.1% by weight. Low-solids-content PI and high-solids-content PI samples are both formulated by reacting 4,4'-p-aminodiphenyl ether (“ODA”) and pyromellitic dianhydride (“PMDA”) in an NMP and / or NN-dimethylacetamide (“DMAc”) solvent. Low-solids-content PIs (e.g., “first PI”) have a solids content of approximately 13.5% by weight, while high-solids-content PI samples (e.g., “second PI”, “third PI”, and “fourth PI”) have a solids content between approximately 22.0% and 30.2% by weight. PI samples filled with fillers other than additives that reduce dielectric constant (e.g., “filled PIs”) have also been prepared. PBIs (e.g., poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole]) are prepared from m-phenylenediamine (“MPD”) and 3,3',4,4'-tetraaminobiphenyltetrahydrochloride dihydrate (“TABT”) in DMAc and / or NMP solvents, with a solids content of approximately 26.0% by weight. A PBI example is provided by PBI Performance Products, Inc. (Charlotte, North Carolina).

[0063] Once prepared, the wire samples are formed by applying enamel varnish to the conductor and curing the wire sample. This creates samples that control the sample and differentiate between different amounts of additives that reduce or decrease the dielectric constant. Unless otherwise stated, the enamel wire samples discussed in the examples are prepared as 18 AWG wire with a “thick” enamel deposit. In other words, wire enamel is applied to 18 AWG copper wire using a multi-coating and wiping die. The nominal insulation thickness of a “thick” enamel deposit is approximately 3.0 mils (76 micrometers).

[0064] The first example shown in Table 1 compares the effects of adding dibenzyltoluene (“DBT”) or hydrogenated terphenyl (“HTP”) as additives to various types of enamels to reduce the dielectric constant. Insulating film samples were prepared and measured for these examples. Control samples containing PI and PAI enamels were compared with samples including DBT and HTP added to the enamels. Additionally, several comparative examples were prepared with mineral oil and cyrene added to the enamels. The relative dielectric constant ε of each sample was measured under laboratory conditions. rThe dielectric constant of a parallel-plate capacitor is calculated using the following equation 1:

[0065] in (1)

[0066] The thickness "d" of the insulating sample was measured using a Fischer Technology FMP 40 dual-view coating thickness gauge. The bottom electrode had a diameter of 25 mm, and the top electrode had a diameter of 15.2 mm. Capacitance was measured at 25°C using a QuadTech 7600 RLC meter with a 2000V AC signal at 1 kHz. The dielectric constant ("k") was then calculated to be the relative dielectric constant (ε). r ) and vacuum permittivity (ε O The ratio of ).

[0067]

[0068] Table 1: Using DBT or HTP additives to reduce dielectric constant

[0069] As shown in Table 1, adding DBT or HTP additives to various types of enamel coatings results in a decrease in dielectric constant. For example, the dielectric constant "k" of the first PI decreases by approximately 0.7 when using DBT additives, the dielectric constant of the first PAI decreases by approximately 0.9 when using DBT additives, and the dielectric constant of the filled PI decreases by approximately 0.85. Other examples also illustrate the reduction in dielectric constant by combining DBT and / or HTP additives. Additionally, using DBT or HTP additives results in a decrease in dielectric constant compared to adding mineral oil to the enamel coating (used as a liquid additive for comparison with DBT or HTP). In fact, adding mineral oil typically increases the dielectric constant.

[0070] The second example shown in Table 2 evaluates the effect of adding DBT to the PI enamel layer on the electrical properties of the magnetic wire. A control wire sample with a first PI enamel was compared to a wire sample prepared with a first PI enamel coated with DBT additive. Approximately 4.45% by weight of DBT additive was included in the varnish used to form the enamel layer on the magnetic wire. Once the samples were prepared, the dielectric strength and PDIV of the samples were measured. Industry-standard PDIV testing was performed using a commercially available PDIV tester, in which a specific ramp voltage was applied to the wire sample at a constant current, and an appropriate PDIV value was determined. The root mean square (“RMS”) PDIV of the round wire sample was reported, a value below the peak PDIV that the wire could withstand. To determine dielectric breakdown of the round wire sample, ramp voltages up to 20,000 volts were applied to the twisted pair formed from the wire at different temperatures, and insulation failures or breakdown points were identified.

[0071]

[0072] Table 2: Electrical performance results using additives that reduce dielectric constant

[0073] As shown in Table 2, the use of DBT additives during the insulation layer formation process can improve the PDIV of the magnetic wire. Additionally, the dielectric strength or dielectric breakdown voltage may be enhanced, especially at higher temperatures. In other words, the electrical properties of the magnetic wire can be improved due to the use of additives that reduce the dielectric constant of the insulation layer.

[0074] The third example shown in Table 3 compares the effects of using different additives that reduce the dielectric constant during the formation of magnetic wire enamel insulation. The polycyclic aromatic hydrocarbon (“PAH”) additives used included dibenzyltoluene (“DBT”), Therminol 75, and Therminol 66 (also known as “HTP”). Wire samples were prepared using a first PI with varying amounts of the additives (used during sample formation). Control samples were also prepared. Each sample was evaluated using the methods described above and with reference to Table 1 to determine the dielectric constant of the enamel layer.

[0075]

[0076] Table 3: Reduction of dielectric constant using different PAH additives (PI)

[0077] As shown in Table 3, the addition of each additive resulted in a decrease in dielectric constant. Terinyl alcohol 66 (“HTP”) appears to have the most recent performance and resulted in the largest reduction in dielectric constant. It can be concluded that the use of PAH additives that reduce dielectric constant (e.g., polyphenyl, polybenzyl, etc., and / or their fully or partially hydrogenated compounds) may reduce the dielectric constant of enamel wire and / or other types of wire insulation. Additionally, the use of higher weight percentages of additives generally leads to a decrease in dielectric constant.

[0078] The following examples are intended to be illustrative and not limiting, and represent specific embodiments of the invention. Samples of extruded thermoplastic insulation structures were prepared and evaluated. The following examples illustrate the effects observed and measured when various dielectric constant-reducing additives were incorporated into extruded thermoplastic films simulating magnetic wire insulation layers. Each sample was prepared by incorporating suitable additives into a PEEK polymer material. Powder from PEEK resin materials with different additives was compressed into polymer films with PEEK as the base polymer material. The thickness of each prepared film was approximately 120 micrometers. After film preparation, the relative permittivity ε of each sample was measured under laboratory conditions. r The dielectric constant is calculated using Equation 1 above.

[0079]

[0080] Table 4: Reduction of PEEK dielectric constant using different polycyclic aromatic hydrocarbon (PAH) additives

[0081] As shown in Table 4, the addition of each additive resulted in a decrease in dielectric constant. Terinyl alcohol 66 (“HTP”) appeared to have the best performance and resulted in the largest reduction in dielectric constant. It can be concluded that the dielectric constant of thermoplastic magnetic wire insulation can be reduced by using PAH additives that lower the dielectric constant (e.g., polyphenyl, polybenzyl, etc., and / or their fully or partially hydrogenated compounds). Additionally, the use of higher weight percentages of additives generally leads to a decrease in dielectric constant.

[0082] Unless expressly stated otherwise, or as understood in the context of use, conditional language, such as “may,” “possibly,” “perhaps,” or “maybe,” is generally intended to express that certain embodiments may include certain features, elements, and / or operations, while other embodiments do not. Therefore, such conditional language is not generally intended to imply that such features, elements, and / or operations are necessary in any way for one or more embodiments, or that one or more embodiments necessarily include logic for determining whether such features, elements, and / or operations are included or will be performed in any particular embodiment, regardless of user input or prompting.

[0083] Many modifications and other embodiments of the disclosure set forth herein will be apparent from the foregoing description and the accompanying drawings. Therefore, it should be understood that this disclosure is not limited to the specific embodiments disclosed, and that modifications and other embodiments are intended to be included within the scope of the appended claims. While specific terminology is used herein, it is used only in a general and descriptive sense and not for limiting purposes.

Claims

1. A magnetic wire, comprising: conductor; as well as At least one insulating layer is formed around the conductor, the insulating layer comprising: Basic polymer materials; and One or more additives incorporated into the base polymer material, said one or more additives comprising at least one of the following: (i) polycyclic aromatic hydrocarbons or (ii) partially or fully hydrogenated compounds of polycyclic aromatic hydrocarbons. In this context, the one or more additives reduce the dielectric constant of the insulating layer, relative to a controlled insulating layer formed solely from the base polymer material.

2. The magnetic wire according to claim 1, wherein, The one or more additives include at least one polyphenyl group.

3. The magnetic wire according to claim 1, wherein, The one or more additives include at least one polybenzyl group.

4. The magnetic wire according to claim 1, wherein, The one or more additives include at least one of the following: (i) dibenzyltoluene, (ii) hydrogenated terphenyl, (iii) terphenyl or (iv) tetraphenyl.

5. The magnetic wire according to claim 1, wherein, The one or more additives include at least one additive with a boiling point of at least 250°C under standard atmospheric pressure.

6. The magnetic wire according to claim 1, wherein, The one or more additives comprise between 1.0% and 60.0% by weight of the insulating material used to form the insulating layer.

7. The magnetic wire according to claim 1, wherein, The base polymer material includes thermosetting materials.

8. The magnetic wire according to claim 7, wherein, The thermosetting material comprises at least one of the following: (i) polyimide, (ii) polyamide-imide, (iii) polyester-imide, (iv) polyamide-ester-imide, (v) polyether-imide, (vi) polybenzimidazole, or (vii) poly(benzimidazole-imide).

9. The magnetic wire according to claim 1, wherein, The base polymer material includes thermoplastic materials.

10. The magnetic wire according to claim 9, wherein, The thermoplastic material includes one of the following: (i) polyetheretherketone, (ii) polyaryletherketone, (iii) polyetherketoneketone, (iv) polyphenylsulfone, (v) polyethersulfone, (vi) poly(imide sulfone), (vii) aromatic polyamide, or (vii) polyphenylene sulfide.

11. The magnetic wire according to claim 1, wherein, The first dielectric constant of the insulating layer is at least 0.3 lower than the second dielectric constant of the control insulating layer.

12. The magnetic wire according to claim 1, wherein, The first partial discharge initiation voltage of the insulating layer is at least 5.0% higher than the second partial discharge initiation voltage of the control insulating layer.

13. A magnetic wire, comprising: conductor; as well as At least one insulating layer is formed around the conductor, the insulating layer comprising: Basic thermosetting polymer materials; and One or more additives incorporated into the base polymer material, the one or more additives comprising at least one of the following: (i) polycyclic aromatic hydrocarbons or (ii) partially or fully hydrogenated compounds of polycyclic aromatic hydrocarbons. In this context, the one or more additives reduce the dielectric constant of the insulating layer, relative to a controlled insulating layer formed solely from the base polymer material.

14. The magnetic wire according to claim 13, wherein, Compared to a controlled insulating layer formed solely from the base thermosetting polymer material, the one or more additives reduce the dielectric constant of the insulating layer.

15. The magnetic wire according to claim 13, wherein, The one or more additives include at least one polyphenyl group.

16. The magnetic wire according to claim 13, wherein, The one or more additives include at least one polybenzyl group.

17. The magnetic wire according to claim 13, wherein, The one or more additives include at least one of the following: (i) dibenzyltoluene, (ii) hydrogenated terphenyl, (iii) terphenyl or (iv) tetraphenyl.

18. The magnetic wire according to claim 13, wherein, The one or more additives comprise between 1.0% and 60.0% by weight of the insulating material used to form the insulating layer.

19. The magnetic wire according to claim 13, wherein, The basic thermosetting polymer material includes at least one of the following: (i) polyimide, (ii) polyamide-imide, (iii) polyester-imide, (iv) polyamide-ester-imide, (v) polyether-imide, (vi) polybenzimidazole, or (vii) poly(benzimidazole-imide).

20. The magnetic wire according to claim 1, wherein, The first dielectric constant of the insulating layer is at least 0.3 lower than the second dielectric constant of the control insulating layer.

21. A method for forming magnetic wires, the method comprising: Provide conductor; as well as At least one insulating layer is formed around the conductor, the insulating layer comprising: Basic polymer materials; and One or more additives incorporated into the base polymer material, said one or more additives comprising at least one of the following: (i) polycyclic aromatic hydrocarbons or (ii) partially or fully hydrogenated compounds of polycyclic aromatic hydrocarbons. In this context, the one or more additives reduce the dielectric constant of the insulating layer, relative to a controlled insulating layer formed solely from the base polymer material.

22. The method according to claim 21, wherein, The one or more additives include at least one polyphenyl group.

23. The method according to claim 21, wherein, The one or more additives include at least one polybenzyl group.

24. The method according to claim 21, wherein, The one or more additives include at least one of the following: (i) dibenzyltoluene, (ii) hydrogenated terphenyl, (iii) terphenyl or (iv) tetraphenyl.

25. The method according to claim 21, wherein, The one or more additives include at least one additive with a boiling point of at least 250°C under standard atmospheric pressure.

26. The method according to claim 21, wherein, The one or more additives comprise between 1.0% and 60.0% by weight of the insulating material used to form the insulating layer.

27. The method according to claim 21, wherein, The base polymer material includes thermosetting materials.

28. The method according to claim 27, wherein, The thermosetting material includes at least one of the following: (i) polyimide, (ii) polyamide-imide, (iii) polyester-imide, (iv) polyamide-ester-imide, (v) polyether-imide, (vi) polybenzimidazole, or (vii) poly(benzimidazole-imide).

29. The method according to claim 21, wherein, The base polymer material includes thermoplastic materials.

30. The method according to claim 29, wherein, The thermoplastic material includes one of the following: (i) polyetheretherketone, (ii) polyaryletherketone, (iii) polyetherketoneketone, (iv) polyphenylsulfone, (v) polyethersulfone, (vi) poly(imide sulfone), (vii) aromatic polyamide, or (vii) polyphenylene sulfide.

31. The method according to claim 21, wherein, The first dielectric constant of the insulating layer is at least 0.3 lower than the second dielectric constant of the control insulating layer.

32. The method according to claim 21, wherein, The first partial discharge initiation voltage of the insulating layer is at least 5.0% higher than the second partial discharge initiation voltage of the control insulating layer.

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