KR20200142899A - Insulating winding wire and method for preparing the same - Google Patents

Abstract

The present invention relates to an insulated winding and a manufacturing method thereof, and more specifically, to an insulated winding and a manufacturing method thereof, in which since an insulating layer can be formed thick, the internal partial discharge characteristics are excellent, the adhesion between the insulating layer and the conductor enclosed by the insulating layer is excellent, and appearance defects such as non-uniform thickness of the insulating layer can be effectively suppressed.

Description

Insulating winding wire and method for preparing the same}

The present invention relates to an insulating winding and a method of manufacturing the same. Specifically, the present invention has excellent internal partial discharge characteristics because the insulating layer can be formed thick, has excellent adhesion between the insulating layer and the conductor wrapped by the insulating layer, and effectively suppresses appearance defects such as uneven thickness of the insulating layer. It relates to an insulated winding and a method of manufacturing the same.

In general, an insulated winding is a wire that is wound in the form of a coil inside an electric device and serves to mutually convert electrical energy and mechanical energy through a magnetic energy conversion process.

Such an insulating winding is usually composed of a conductor wire such as copper and an insulating layer surrounding it, and the insulating layer may be formed through processes such as drying and curing after coating an insulating varnish made of an organic solvent and a polymer resin on the surface of the conductor. .

Conventional insulated windings are currently used in various fields such as heavy electrical products, automobile parts, home appliances, medical devices, and core materials in the aerospace industry, and when applied to motors in high voltage and high temperature environments according to high output demands, corona resistance characteristics are insufficient. There is a problem in that a partial discharge occurs due to a corona phenomenon in which an electric field is concentrated between the insulating films forming the insulating layer or inside the insulating film when the lower surface is formed.

In particular, collision of charged particles generated by the corona phenomenon causes heat generation and decomposition of the insulating layer, and as a result, insulation breakdown may occur. In addition, due to recent energy savings, systems employing inverter motors, etc., are being used.In these systems, there are many cases of insulation breakdown due to inverter serge, and insulation breakdown due to such inverter surge. It has also been proven that overvoltage caused by inverter surge causes corona discharge.

Insulation windings are known in which inorganic insulating particles such as silica and titanium dioxide are added to a resin forming an insulating layer in order to impart sufficient corona resistance and internal partial discharge characteristics to these insulating windings, and these inorganic insulating particles are included in a large amount. In this case, a number of cracks are generated inside the insulating layer, and as a result, the original purpose of the corona resistance and internal partial discharge characteristics cannot be improved.

Furthermore, these conventional insulated windings can be used for motors with a driving voltage of 400 V or less, but have limitations that cannot be applied to motors with a driving voltage of 600 V or more. Increasing the thickness of the insulating layer to give corona characteristics and internal partial discharge characteristics can be considered, but there is also a limit to increasing the thickness of the insulating layer formed by coating of insulating varnish to 100 µm or more as in the prior art. have.

Therefore, since the insulating layer can be formed thick, the internal partial discharge characteristics are excellent, the adhesion between the insulating layer and the conductor wrapped by the insulating layer is excellent, and the insulating winding that can effectively suppress appearance defects such as uneven thickness of the insulating layer. And there is an urgent need for a manufacturing method thereof.

An object of the present invention is to provide an insulating winding and a method of manufacturing the same, which can be formed in a thick insulating layer, and thus has excellent corona resistance characteristics and internal partial discharge characteristics, and thus applicable under high voltage and high temperature environments.

In addition, an object of the present invention is to provide an insulating winding and a method of manufacturing the same, which can improve adhesion between a conductor and an insulating layer and effectively suppress appearance defects such as non-uniform thickness of the insulating layer.

In order to solve the above problems, the present invention,

An insulated wire comprising a conductor and an insulating layer surrounding the conductor, wherein the insulating layer directly surrounds the conductor and covers the insulating coating layer formed by coating of an insulating varnish and the insulating coating layer, and is formed by extrusion of a polymer resin It includes an extruded layer, the total thickness of the insulating layer is characterized in that 50 to 300 ㎛, it provides an insulated wire.

Here, the insulating coating layer has a thickness of 20 to 50 µm, and the insulating extruded layer has a thickness of 50 to 250 µm.

In addition, when the insulating layer is cut 360° in the circumferential direction of the conductor at an arbitrary point of the insulated wire and the insulated wire is stretched by 15% at a tensile speed of 300 mm/min, the conductor and the insulation at the cut portion When the layer is separated, the length of the film, which is the length of the conductor exposed to the outside, is less than the width of the conductor, and the maximum and minimum values of the values that can be measured as the thickness of the insulating layer in an arbitrary cross section of the insulated wire It provides an insulated wire, characterized in that the difference is 100 μm or less.

In addition, the insulating varnish forming the insulating coating layer provides an insulated wire, characterized in that it contains a polyimide resin as a base resin.

Here, the insulating varnish provides an insulated wire, characterized in that it further comprises 5 to 15 parts by weight of nano-inorganic particles based on 100 parts by weight of the base resin.

In addition, the insulating varnish provides an insulated wire, characterized in that it further comprises 1 to 3 parts by weight of an adhesive based on 100 parts by weight of the base resin.

On the other hand, the polymer resin forming the insulating extruded layer provides an insulated wire, characterized in that it comprises a polymer resin having a melting point (Tm) of 300 °C or higher.

Here, the polymer resin provides an insulated wire, characterized in that it contains polyether ether ketone (PEEK).

On the other hand, as the manufacturing method of the insulated wire, the step of manufacturing a conductor by drawing; Forming an insulating coating layer on the surface of the conductor; Preheating the conductor; And extruding an insulating extruded layer on the insulating coating layer to form an insulated wire.

Here, the step of preheating the conductor provides a method of manufacturing an insulated wire, characterized in that the conductor is preheated to 180 to 200°C.

In addition, the step of forming the insulating coating layer is characterized in that when the insulating varnish forming the insulating coating layer is coated on the surface of the conductor, the coating layer is undermined to minimize the effect of residual solvent. to provide.

In addition, the step of forming the insulating extruded layer provides a method of manufacturing an insulated wire, characterized in that the polymer resin forming the insulating extruded layer is extruded at a temperature of 340° C. or higher.

The insulating winding according to the present invention can have an insulating layer thicker than the thickness of the insulating layer formed by the conventional coating, as some of the insulating layers are formed by extrusion rather than coating, so that the corona resistance and internal partial discharge characteristics are greatly improved. Shows an excellent effect.

In addition, the insulating winding according to the present invention exhibits excellent effects in that the adhesion between the conductor and the insulating layer and the uniformity of the thickness of the insulating layer are precisely controlled, thereby greatly improving the corona resistance characteristics and the internal partial discharge characteristics.

1 schematically shows the structure of an insulating winding according to the present invention.
FIG. 2 schematically shows a cross-sectional structure of the insulating winding shown in FIG. 1.
3 schematically shows a method of manufacturing an insulating winding according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art. The same reference numbers throughout the specification denote the same elements.

1 schematically shows the structure of an insulating winding according to the present invention, and FIG. 2 schematically illustrates a cross-sectional structure of the insulating winding shown in FIG. 1.

1 and 2, the insulating winding according to the present invention includes a conductor 10, an insulating layer 20 surrounding the conductor 10, and the insulating layer 20 is the conductor 10 An insulating coating layer 21 directly surrounding the insulating coating layer 21 and an insulating extruded layer 22 surrounding the insulating coating layer 21 may be included.

The conductor 10 serves as a path through which current flows, and may be made of a metal having high electrical conductivity, for example, copper, copper alloy, aluminum, aluminum alloy, etc., and oxygen-free when considering solderability. It is preferably made of copper.

The cross-sectional shape of the conductor 10 is not particularly limited, and may have various cross-sectional shapes according to the use of the insulating winding, for example, round, oval, square, and flat squares in which corners are rounded with a specific radius of curvature. As shown in Fig. 1, when the cross-sectional shape of the conductor 10 is flat, the empty space between the insulated wires can be reduced when the insulated wire is wound, compared to the case where the cross-sectional shape is circular, and alignment winding is possible. Thus, there is an advantage of increasing the efficiency of electricity change and reducing the operating noise.

The insulating coating layer 21, which directly surrounds the conductor 10 in the insulating layer 20 and realizes adhesion between the conductor 10 and the insulating layer 20, is a polyamide imide resin, polyimide resin as a base resin. Resin, polyamide resin, polyvinyl formal resin, polyurethane resin, heat-resistant polyurethane resin, polyester resin, polyester imide resin, etc., including at least one resin selected from, preferably a polyimide resin having excellent heat resistance It can be formed by coating an insulating varnish.

Here, the insulating coating layer 21 may be formed by a baking process in which the insulating varnish is coated on the surface of the conductor 10 and then dried and cured at a high temperature. When forming an insulating coating layer in a conventional insulated wire, the above The temperature conditions of the baking process were about 240°C.

However, in the case of the present invention, an insulating extruded layer 22 by extrusion is additionally formed on the insulating coating layer 21, and when the insulating extruded layer 22 is extruded, the residual solvent in the insulating coating layer 21 boils under high temperature. A problem of appearance defects in which the thickness of the insulating layer 20 is non-uniform may occur due to the rise of the insulating extruded layer 22 and the like.

Therefore, in the present invention, the insulating coating layer 21 needs to be extruded after removing the residual solvent in the insulating coating layer 21 by undermining the insulating coating layer 21, and the insulating coating layer 21 It is preferable to include a polyimide resin having a high heat resistance of 240° C. or higher for the above-described under-baking at high temperature.

The insulating varnish forming the insulating coating layer 21, in addition to the base resin, prevents insulation breakdown due to corona discharge due to inverter serge, and improves thermal conductivity of the insulating layer 20, reduces thermal expansion, and strength Nano-inorganic particles that can perform a role of improvement, for example, silica, alumina, titanium dioxide, zirconia, yttria, mica, clay, zeolite, chromium oxide, zinc oxide, iron oxide, magnesium oxide, calcium oxide, oxide It may further include one or more types of nano-inorganic particles selected from scandinium, barium oxide, and the like.

In order for the nano-inorganic particles to effectively exhibit corona resistance, excellent dispersion characteristics, ultra-fine particle size, preferably, nano-size of 4 to 100 nm, high specific surface area (BET), preferably, 100 to 300 m 2 / A specific surface area of g, a high purity, preferably a purity of at least 95%, a spherical particle shape, absence of pores, etc. are required, and various methods of improving these properties are already known.

In particular, since the nano-inorganic particles generally have a hydrophilic surface, there is a problem that it is difficult to aggregate and disperse in the hydrophobic base resin, and thus the nano-inorganic particles in order to improve the dispersibility of the nano-inorganic particles in the base resin. The surface of the nano-inorganic particles may be hydrophobically modified by coating a surface modifier having a functional group capable of covalently bonding or non-covalent bonding with the resin on the surface of the particles.

Specifically, the surface-modified nano-inorganic particles make a mixture by adding the nano-inorganic particles to a solvent such as toluene, xylene, ethanol, cresol, etc., and amine, epoxy, thiol, carboxylic acid, sulfonic acid, phosphoric acid, It can be prepared by reacting by adding at least one surface modifier selected from the group consisting of phosphinic acid, cyanic acid and silane.

The content of the inorganic nanoparticles may be 5 to 15 parts by weight based on 100 parts by weight of the base resin. When the content of the nano-inorganic particles is less than 5 parts by weight, the corona resistance may be insufficient, whereas when the content is more than 15 parts by weight, the adhesion between the conductor 10 and the insulating coating layer 22, the insulating layer 20 Flexibility, etc. may decrease.

The insulating varnish forming the insulating coating layer 21 may further include an adhesion agent, that is, an adhesion improving agent to further improve adhesion between the conductor 10 and the insulating coating layer 21, and the adhesion The agent may contain at least one adhesive selected from the group consisting of melamine-based alkoxy melamine resins such as butoxy, amine-based such as trialkylamine, mercaptan-based such as mercapto benzimidazole, and polycarbodiimide. I can.

Here, the content of the adhesive may be 1 to 3 parts by weight based on 100 parts by weight of the resin constituting each varnish layer. When the content of the adhesive is less than 1 part by weight, the effect of improving the adhesion between the conductor 10 and the insulating coating layer 21 may be insignificant, whereas when the content of the adhesive is more than 3 parts by weight, the extrusion of the insulating extruded layer 22 When the adhesive agent is decomposed under high temperature, air bubbles are generated to make the insulating extruded layer 22 swell, and the thickness of the insulating layer 20 may be uneven, thereby causing a problem of appearance defects.

The insulating extruded layer 22 is formed by extrusion rather than coating, so that the thickness of the insulating layer 20 can be formed to a maximum of 300 µm, thereby implementing sufficient corona resistance and internal partial discharge characteristics, thereby achieving high voltage according to high power requirements. And it is possible to provide an insulating winding applicable under high temperature environment.

The insulating extruded layer 22 may be formed by extrusion of a polymer resin, and the polymer resin has, for example, a melting point (Tm) of 300° C. or more, preferably 340° C. or more, measured according to the standard ASTM D3418. And, the thermal conductivity measured according to the standard ASTM E1630 is 0.20 W/m·K or more, preferably 0.24 W/m·K or more, and the melt flow rate (MFR) measured according to ASTM D1238 (400°C, 2.16) kg) may be 8 g/10min or more, preferably 10 g/10min or more, and more preferably polyetheretherketone (PEEK).

In the insulated wire according to the present invention, the insulating coating layer 21 may have a thickness of about 20 to 50 μm, and the insulating extruded layer 22 may have a thickness of about 30 μm or more, for example, 30 to 250 μm Accordingly, the total thickness of the insulating layer 20 may be formed to a sufficient thickness of 50 to 300 μm, whereby the insulated wire may implement sufficient corona resistance and internal partial discharge characteristics.

Here, the thickness of each of the insulation coating layer 21, the insulation extrusion layer, and the insulation layer (hereinafter,'insulation coating layer, etc.') is a value that can be measured by the thickness of the insulation coating layer, etc. in an arbitrary cross section of the insulation wire. It can be calculated as the average of the maximum and minimum values.

In addition, by improving the adhesion between the conductor 10 and the insulating coating layer 21 by the configuration of the insulating coating layer 21 and the insulating extrusion layer 22 described above, the conductor 10 and the insulating layer (20) The gap that may cause insulation breakdown due to the concentration of the electric field between them can be minimized, and the thickness deviation of the insulating layer 20 is minimized to form a uniform thickness, thereby providing an insulated wire having an excellent appearance. have.

Specifically, when the insulating layer 20 is cut 360° in the circumferential direction of the conductor 10 at an arbitrary point of the insulated wire, the insulated wire is stretched by 15% at a tensile speed of 300 mm/min. The length of the conductor 10 exposed to the outside by separating the conductor 10 and the insulating layer 20 at the cut portion, that is, the length of the film is less than the width length of the conductor 10, The difference between the maximum value and the minimum value among the values that can be measured by the thickness of the insulating layer 20 in the cross section of is adjusted to be 100 μm or less, thereby maximizing the corona resistance and internal partial discharge characteristics of the insulated wire.

3 schematically shows a method of manufacturing an insulating winding according to the present invention.

As shown in FIG. 3, the method of manufacturing an insulated wire according to the present invention includes the step of manufacturing the conductor 10 by drawing it to have a desired cross-sectional shape (S100), and preheating the conductor 10 to a desired temperature. Step (S200), forming the insulating coating layer 21 by coating the insulating varnish on the surface of the conductor 10 (S300), extruding the insulating extrusion layer 22 on the insulating coating layer 21 And forming (S400).

Here, in the step of preheating the conductor 10 (S200), the conductor 10 and the conductor 10 are preheated to about 180 to 200°C through induction heating or the like before forming the insulating coating layer 21. The adhesion between the insulating coating layers 21 may be further improved.

In addition, in the step of forming the insulating coating layer 21 (S300), when the insulating varnish is coated on the surface of the conductor 10, the residual solvent in the insulating varnish may be pre-evaporated to remove the residual solvent. When extruding for the formation of the insulating extruded layer 22, the residual solvent remaining in the insulating coating layer 21 is vaporized at a high temperature, thereby preventing the insulating extruded layer 22 from being affected.

In the step (S400), the insulating extruded layer 22 may be extruded at a temperature capable of melting and extruding the polymer resin included in the insulating extruded layer 22, for example, at a temperature of about 340 °C or higher, By controlling the cooling rate after extrusion, the color of the insulating extruded layer 22 formed by controlling the degree of crystallinity of the polymer resin may be controlled.

For example, if the cooling rate is slowed down, the crystallinity of the polymer resin increases and the color of the insulating extruded layer 22 becomes opaque, whereas when the cooling rate is increased, the crystallinity of the polymer resin decreases and the color of the insulating extruded layer 22 It becomes transparent.

Although the present specification has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the claims described below. You will be able to do it. Therefore, if the modified implementation basically includes the elements of the claims of the present invention, all should be considered to be included in the technical scope of the present invention.

10: conductor 20: insulating layer

Claims (12)

An insulated wire comprising a conductor and an insulating layer surrounding the conductor,
The insulating layer directly surrounds the conductor and includes an insulating coating layer formed by coating an insulating varnish, and an insulating extrusion layer surrounding the insulating coating layer and formed by extrusion of a polymer resin,
Insulated wire, characterized in that the total thickness of the insulating layer is 50 to 300 ㎛. The method of claim 1,
The insulating coating layer has a thickness of 20 to 50 µm, and the insulating extruded layer has a thickness of 50 to 250 µm. The method according to claim 1 or 2,
When the insulating layer is cut 360° in the circumferential direction of the conductor at an arbitrary point of the insulated wire and the insulated wire is elongated by 15% at a tensile speed of 300 mm/min, the conductor and the insulating layer are The length of the film, which is the length of the conductor exposed to the outside by being separated, is less than the width of the conductor, and the difference between the maximum value and the minimum value among the values that can be measured as the thickness of the insulation layer in an arbitrary cross section of the insulation wire Insulated wire, characterized in that 100 µm or less. The method according to claim 1 or 2,
The insulating varnish forming the insulating coating layer is characterized in that it contains a polyimide resin as a base resin, insulated wire. The method of claim 4,
The insulating varnish further comprises 5 to 15 parts by weight of inorganic nanoparticles based on 100 parts by weight of the base resin. The method of claim 4,
The insulating varnish further comprises 1 to 3 parts by weight of an adhesive based on 100 parts by weight of the base resin. The method according to claim 1 or 2,
Insulated wire, characterized in that the polymer resin forming the insulating extruded layer comprises a polymer resin having a melting point (Tm) of 300° C. or higher. The method of claim 7,
The polymer resin is characterized in that it contains polyetheretherketone (PEEK), insulated wire. As a method of manufacturing an insulated wire according to claim 1 or 2,
Preparing a conductor by drawing;
Forming an insulating coating layer on the surface of the conductor;
Preheating the conductor; And
A method of manufacturing an insulated wire comprising the step of extruding an insulating extruded layer on the insulating coating layer. The method of claim 9,
The step of preheating the conductor comprises preheating the conductor to 180 to 200 °C. The method of claim 9,
The forming of the insulating coating layer is characterized in that when the insulating varnish forming the insulating coating layer is coated on the surface of the conductor, the insulating coating layer is undermined. The method of claim 9,
In the forming of the insulating extruded layer, the polymer resin forming the insulating extruded layer is extruded at a temperature of 340° C. or higher.

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