JP6747154B2 - Fuse-insulated electric wire and method for manufacturing fusible insulated wire - Google Patents

Description

The present invention relates to an insulated electric wire, a fusible insulated electric wire, and a method for manufacturing them.

Insulated wires used for coils of electrical equipment such as rotating electrical machines and transformers generally have a structure in which an insulating layer is formed on the outer periphery of a conductor molded into a cross-sectional shape corresponding to the application and shape of the coil. ing.

In recent years, electric devices have come to be inverter-controlled for efficiency. Along with this, since a high voltage such as an inverter surge voltage is applied to the coil of the electric device, partial discharge is likely to occur, and the insulating layer may be deteriorated or damaged. Therefore, in order to suppress the deterioration and damage due to partial discharge in the insulating layer, a method of increasing the partial discharge inception voltage (PDIV) is being studied. Examples of this method include a method of forming an insulating layer with a resin having a low relative dielectric constant, and a method of increasing the thickness of the insulating layer.

As a method for forming the insulating layer, a baking method in which an insulating paint obtained by dissolving a resin in an organic solvent is applied to the outer circumference of a conductor and baked, an extrusion method in which a preliminarily prepared resin composition is extrusion-coated on the outer circumference of the conductor, There is a method of using these together. When the insulating layer is formed thickly, the baking method increases the number of times of coating and baking, resulting in high cost, and the thickness of the insulating layer may vary in the circumferential direction. Therefore, the extrusion method is generally used.

Various super engineering plastics have been studied as resins used in the extrusion method, and among them, polyphenylene sulfide resin (hereinafter, also referred to as PPS resin) has attracted attention because of its low dielectric constant (for example, refer to Patent Document 1). ). According to the PPS resin, it is possible to form an insulating layer having a high PDIV and excellent in various properties such as heat resistance and mechanical properties.

JP, 2014-136738, A

By the way, when the insulated electric wire is processed into a coil, the purpose is to maintain the coil shape of the insulated electric wire and to prevent the insulating layer from being worn or damaged by rubbing adjacent insulated electric wires when the coiled shape is adopted. In some cases, the insulated wire is processed into a coil shape and then subjected to a fusion treatment.

As a method of fusion treatment, a method of applying a varnish containing a thermosetting fusible resin such as epoxy or unsaturated polyester to a coil wound with an insulated wire and baking it, or a pre-insulating layer of the insulated wire There is a method in which a fusible insulated electric wire having a fusible layer made of a fusible resin composition formed on the outer periphery is wound into a coil shape and then the fusible layers are fused.

However, with an insulated wire provided with an insulating layer containing a PPS resin as disclosed in Patent Document 1, it is difficult to sufficiently fuse the insulated wires together even if a fusion treatment is performed. Although PPS resin has excellent insulation and heat resistance, it tends to be chemically stable and have a low chemical affinity with the fusible resin composition (fusion layer), and the insulation layer containing PPS resin is fused. This is because the adhesion with the layer is weakened. Therefore, the insulated wire of Patent Document 1 may impair the reliability of the electric device.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for suitably fusing an insulated electric wire including an insulating layer containing a polyphenylene sulfide resin.

According to one aspect of the invention,
A conductor,
An insulating layer disposed on the outer periphery of the conductor, the insulating layer comprising a resin composition containing a polyphenylene sulfide resin,
There is provided an insulated wire in which the insulating layer has a mass concentration ratio O/S of oxygen O to sulfur S of 0.2 or more on the surface.

According to another aspect of the invention,
An insulating layer forming step of forming an insulating layer made of a resin composition containing a polyphenylene sulfide resin on the outer periphery of the conductor;
And a surface modification step of modifying the surface of the insulating layer so that the mass concentration ratio O/S of oxygen O to sulfur S on the surface of the insulating layer becomes 0.2 or more. To be done.

ADVANTAGE OF THE INVENTION According to this invention, the insulated wire provided with the insulating layer containing polyphenylene sulfide resin can be fuse|melted suitably.

It is a sectional view perpendicular to the length direction of the fusible insulated wire concerning one embodiment of the present invention. It is sectional drawing perpendicular|vertical to the length direction of the fusible insulated wire which concerns on other embodiment of this invention. It is a figure which shows FT-IR spectrum in the surface of the insulating layer containing a polyphenylene sulfide resin before and after plasma processing. It is a structure schematic diagram of the manufacturing apparatus which manufactures a fusion-bonded insulated wire. It is a perspective view of the test piece for evaluating the adhesive force after fusion bonding of a fusion-bondable insulated wire.

<One Embodiment of the Present Invention>
An embodiment of the present invention will be described below.

[Structure of fusible insulated wire]
An embodiment of the fusible insulated wire according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view perpendicular to the length direction of a fusible insulated wire according to an embodiment of the present invention. FIG. 2 is a cross-sectional view perpendicular to the length direction of the fusible insulated wire according to another embodiment of the present invention. In addition, in this specification, the numerical range represented using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

As shown in FIG. 1, the fusible insulated electric wire 1 is configured to include a fusible layer 13 so as to cover the outer circumference of an insulated electric wire 10 in which an insulating layer 12 is provided on the outer circumference of a conductor 11.

(conductor)
As the conductor 11, a metal wire made of a metal having high conductivity, for example, a copper wire made of low oxygen copper or oxygen free copper, an aluminum wire, or the like can be used. Although FIG. 1 shows the case where the conductor 11 is a rectangular wire having a substantially rectangular cross section, the conductor 11 is not limited to a rectangular wire, and a round wire having a circular cross section as shown in FIG. 2 can also be used, for example. As the conductor 11, a twisted wire formed by twisting a plurality of round wires can be used. The surface of the conductor 11 may be plated with a metal such as tin or nickel.

(Insulating layer)
An insulating layer 12 is provided on the outer periphery of the conductor 11 so as to cover the conductor 11. The insulating layer 12 is formed by melting a resin composition containing a polyphenylene sulfide resin (PPS resin), extruding the resin composition onto the outer periphery of the conductor 11 to cover the resin composition, and performing a predetermined surface treatment, as will be described in detail later. .. By the surface treatment, the insulating layer 12 is configured such that the mass concentration ratio O/S of oxygen O to sulfur S on the surface is 0.2 or more.

Here, the mass concentration ratio O/S of oxygen O to sulfur S on the surface of the insulating layer 12 will be described with reference to FIG.

The present inventors have studied a method of increasing the adhesion between the insulating layer 12 containing the PPS resin and the fusion bonding layer 13 to sufficiently fuse the insulated electric wires 10 to each other. In the process of the investigation, it was found that when the insulating layer 12 containing the PPS resin was subjected to a predetermined surface treatment for surface modification, the adhesion of the insulating layer 12 to the fusion layer 13 was improved. Note that FIG. 3 shows a case where plasma treatment is used as the surface treatment method.

In order to analyze the difference in the chemical structure before and after the surface modification of the insulating layer 12, the FT-IR (Fourier Transform Infrared Spectroscopy) was used to measure the ATR (Attenuated Total Reflection) method using a Ge prism. The FT-IR spectrum as shown in FIG. 3 was obtained. FIG. 3 is a diagram showing FT-IR spectra on the surface of an insulating layer containing a polyphenylene sulfide resin before and after plasma treatment. In FIG. 3, the horizontal axis represents the wavelength of irradiated infrared light [cm ⁻¹ ] and the vertical axis represents the absorbance, respectively. The thin line shows the FT-IR spectrum before plasma treatment, and the thick line shows the FT-IR spectrum after plasma treatment. Are shown respectively.

As shown in FIG. 3, comparing the spectra of the insulating layer 12 before and after the plasma treatment, the wavelength after the plasma treatment is 3000 to 3200 cm ^−1, which is the absorption band of the molecular structure of the —OH group, as compared with before the plasma treatment. It was confirmed that the absorbance increased at a wavelength of 1000 to 1200 cm ^-1 , which is the absorption band of the molecular structure of -SO group and -SO ₂ group. From this, by modifying the surface of the insulating layer 12, active functional groups such as —OH group, —SO group, and —SO ₂ group are introduced into the PPS resin forming the insulating layer 12, and the fusion property is improved. It was speculated that the chemical interaction with the resin is improved, and thus the adhesion between the insulating layer 12 and the fusion bonding layer 13 is improved.

Therefore, the present inventors conducted elemental analysis on the insulating layer 12 before and after the surface treatment, and examined the correlation between the oxygen concentration on the surface of the insulating layer 12 and the adhesion of the insulating layer 12 to the fusion layer 13. I went. Specifically, the energy dispersive X-ray spectroscopy (EDX) is used to perform elemental analysis on the insulating layer 12 before and after the plasma treatment to obtain the oxygen concentration of the PPS resin. The mass concentration ratio O/S of oxygen O with respect to the sulfur S contained in was determined. As a result, it was found that when the mass concentration ratio O/S increases, the adhesion with the fusion layer 13 increases. When the mass concentration ratio O/S on the surface of the insulating layer 12 that contacts the fusion layer 13 is less than 0.2, the adhesion between the insulation layer 12 and the fusion layer 13 is insufficient, but the mass concentration By surface-modifying the insulating layer 12 so that the ratio O/S is 0.2 or more, the adhesion between the insulating layer 12 and the fusion layer 13 is improved, and the insulated wire 10 can be fused appropriately. The upper limit of the mass concentration ratio O/S is not particularly limited, but is preferably 0.5 or less.

The PPS resin forming the insulating layer 12 is a polymer that includes a repeating unit made of, for example, p-phenylene sulfide, and is excellent not only in electrical characteristics, heat resistance and mechanical characteristics, but also in solvent resistance, oil resistance and the like. From the viewpoint of the heat resistance of the insulating layer 12, the PPS resin preferably contains 85% or more, and more preferably 90% or more, of repeating units of p-phenylene sulfide. The PPS resin may contain a sulfoxide group or an ether group in addition to the repeating unit composed of p-phenylene sulfide, and may contain a substituent on the benzene ring. Further, the molecular chain may have a branched structure or a crosslinked structure via a thioether group or an ether group. For example, as a commercially available product of PPS resin, "Torelina T1881" manufactured by Toray Industries, Inc. can be used.

The resin composition forming the insulating layer 12 may contain a component other than the PPS resin, and is selected from the group consisting of polyamide resin, polyester resin, polyimide resin, polyamideimide resin, polyesterimide resin, and silicone resin, for example. One or more resins can be included. Among these, it is preferable to use a silicone resin (for example, silicone rubber) because the adhesiveness between the insulating layer 12 and the conductor 11 can be improved while keeping the heat resistance of the insulating layer 12 high.

The mixing ratio of the PPS resin and the silicone resin is not particularly limited, but the mass ratio is preferably 90:10 to 98:2. With such a ratio, the adhesion of the insulating layer 12 to the conductor 11 can be improved by the silicone resin without deteriorating the inherent properties of the PPS resin.

Further, the resin composition forming the insulating layer 12 may include an additive other than the resin, for example, a filler such as an inorganic filler. The blending amount of these can be appropriately changed within a range not impairing the effects of the present invention.

The thickness of the insulating layer 12 can be appropriately changed according to the insulation required for the insulated wire 10 and is not particularly limited, but is 160 μm or more from the viewpoint of obtaining a high partial discharge inception voltage (PDIV). Is preferred. On the other hand, when the thickness of the insulating layer 12 becomes excessively large, the insulating layer 12 becomes difficult to follow the bending deformation of the conductor 11 when the fusible insulated electric wire 1 is coiled, and the insulating layer 12 is separated from the conductor 11. May peel off. Therefore, from the viewpoint of adhesion with the conductor 11, the thickness of the insulating layer 12 is preferably 240 μm or less. That is, by setting the thickness of the insulating layer 12 to 160 μm or more and 240 μm or less, PDIV can be increased and high adhesion to the conductor 11 can be realized. The thickness of the insulating layer 12 indicates an average value in the circumferential direction, as will be shown in Examples described later.

The insulating layer 12 preferably has a high degree of crystallinity from the viewpoint of improving chemical, mechanical and thermal performance, and is preferably 95% or more and 100% or less, for example. With such a crystallinity, various characteristics such as insulation, abrasion resistance, chemical resistance, and oil resistance can be improved in the insulating layer 12.
The crystallinity is defined as follows. That is, when the heat of crystallization during crystallization measured while raising the temperature by the differential scanning calorimetry is Hc and the heat of fusion by the differential scanning calorimetry is Hm, the crystallinity α is represented by the following formula (1).
Crystallinity α=(1-Hc/Hm)×100 (1)

(Fusion layer)
A fusion-bonding layer 13 is provided on the outer periphery of the insulating layer 12 so as to cover the insulating layer 12. The fusible layer 13 is made of a fusible resin composition, and when the fusible insulated electric wires 1 are wound and processed into a coil, the fusible insulated electric wires 1 adjacent to each other are fused and fixed. is there. The fusion layer 13 is provided on the insulating layer 12 having an O/S ratio of 0.2 or more due to surface modification, and is formed so as to have high adhesiveness with the insulating layer 12.

The fusible resin composition forming the fusible layer 13 contains a resin that exhibits fusible properties by heating, for example, a thermoplastic resin. Such a thermoplastic resin preferably has a glass transition temperature of room temperature (for example, 25° C.) or higher, a melting point of 155° C. or higher, and a melting point of the thermoplastic resin (PPS resin) forming the insulating layer 12 or lower. By setting the glass transition temperature of the thermoplastic resin forming the fusion bonding layer 13 to room temperature or higher, the deformation of the fusion bonding layer 13 in a room temperature environment can be suppressed. When the melting point of the thermoplastic resin is set to 155° C. or higher and the melting point of the PPS resin or lower to extrude the melted thermoplastic resin around the insulating layer 12 containing the PPS resin to form the fusion bonding layer 13. In addition, it is possible to prevent the insulating layer 12 from being melted and deformed by the heat of the melted thermoplastic resin. As such a resin, for example, a phenoxy resin, a polyester resin, a polyamide resin, or the like can be used. When a thermoplastic resin is used as the fusible resin, the fusible layer 13 may be formed by extrusion.

As the phenoxy resin, a resin containing bisphenol A, bisphenol S, or bisphenol F as a main component or an epoxy-modified phenoxy resin can be used. For example, as a commercially available product of phenoxy resin, a copolymer of bisphenol A epoxy and bisphenol F epoxy such as "YP-70" and "ZX-1356-2" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., or Nippon Steel & Sumikin A bisphenol A phenoxy resin and a bisphenol F phenoxy resin such as "YP-50" and "FX-316" manufactured by Kagaku Co., Ltd. can be used.

As a commercial product of the polyester resin, for example, polybutylene terephthalate such as “Trecon 1401X06” manufactured by Toray Industries, Inc., polyethylene terephthalate, or the like can be used.

As the polyamide resin, for example. Various copolyamides, 6-nylon, 6,6-nylon, 6,10-nylon, etc. can be used.

[Method for manufacturing fusible insulated wire]
Next, a method for manufacturing the above-described fusible insulated wire 1 will be described with reference to FIG. FIG. 4 is a schematic configuration diagram of a manufacturing apparatus for manufacturing the fusible insulated wire. The manufacturing method of the fusible insulated wire 1 of the present embodiment includes a preparatory step S10, a preheating step S20, an insulating layer forming step S30, a surface modifying step S40, a carrying step S50, and a fusion layer forming step. S60 and.

(Preparing step S10)
First, a conductor 11 having a substantially rectangular cross section as shown in FIG. 1 (hereinafter, also simply referred to as a rectangular conductor 11) is prepared.

(Preliminary heating step S20)
Then, in order to improve the adhesion between the flat conductor 11 and the insulating layer 12, the flat conductor 11 is preheated before forming the insulating layer 12. Specifically, the rectangular conductor 11 sent from the feeder 101 is introduced into the preheating furnace 102 to preheat the rectangular conductor 11. Thereby, when the resin composition to be melted is extruded onto the outer periphery of the rectangular conductor 11 in the insulating layer forming step S30 described later, the resin composition can be prevented from being cooled by the rectangular conductor 11 and formed. It is possible to improve the adhesion of the insulating layer 12.

The temperature at which the rectangular conductor 11 is preheated may be equal to or higher than the melting point of the PPS resin. Specifically, the temperature is preferably 280° C. or higher, and more preferably 300° C. or higher and 320° C. or lower. By preheating the rectangular conductor 11 at such a temperature, the adhesion between the rectangular conductor 11 and the insulating layer 12 can be enhanced.

In the preheating furnace 102, it is preferable to heat the rectangular conductor 11 in an inert gas atmosphere. In the preheating furnace 102, the rectangular conductor 11 is exposed to a high temperature environment and its surface is oxidized, so that the adhesion of the insulating layer 12 may be deteriorated. However, the inside of the preheating furnace 102 is set to an inert gas atmosphere. As a result, it is possible to suppress the oxidation of the rectangular conductor 11 and the decrease in the adhesiveness of the insulating layer 12 due to the formation of the oxide film. As the inert gas, for example, a known gas such as nitrogen gas, which is a low-cost general-purpose gas, or helium gas, which has excellent thermal conductivity, can be used.

(Insulating layer forming step S30)
Then, the insulating layer forming step S30 is performed. The insulating layer forming step S30 includes an extrusion coating step S31 and a cooling step S32.

Specifically, in the extrusion coating step S31, the heated rectangular conductor 11 is introduced into the first extruder 103, and the outer periphery of the rectangular conductor 11 is extruded with a predetermined thickness to coat the resin composition containing the PPS resin. Let The extrusion temperature in the first extruder is 280° C. or higher, which is the melting point of the PPS resin, preferably 300° C. or higher and 320° C. or lower.

Subsequently, in the cooling step S32, the rectangular conductor 11 coated with the resin composition containing the PPS resin is introduced into the first cooling device 104 and cooled to promote crystallization of the PPS resin and obtain desired crystals. An insulating layer 12 having a degree of conversion is formed.

In the cooling step S32, it is preferable to cool the insulating layer 12 so that the crystallinity is 95% or more. In order to obtain such crystallinity, for example, a resin composition containing a PPS resin is treated at a temperature below the melting point of the PPS resin (eg, 280° C.) and at a temperature at which the PPS resin is crystallized (eg, 200° C.). After cooling, it may be cooled so as to maintain the crystallization temperature of the PPS resin (for example, 200° C.). Thereby, the crystallization of the PPS resin is promoted, and the crystallinity of the PPS resin in the obtained insulating layer 12 can be increased to, for example, 95% or more. As a cooling method, a known method such as water cooling in a water tank can be used.

(Surface modification step S40)
Subsequently, in the surface modification step S40, the rectangular conductor 11 on which the insulating layer 12 is formed is introduced into the surface treatment device 105, and the insulating layer 12 is subjected to surface treatment. As a result, active functional groups such as —OH groups, —SO groups, and —SO ₂ groups are introduced into the surface of the insulating layer 12, and the mass concentration ratio O/S of oxygen O to sulfur S on the surface of the insulating layer 12 is increased. The surface is modified so as to be 0.2 or more. Thereby, the insulated wire 10 is obtained.

In the surface modification step S40, for example, plasma treatment is performed as the surface treatment. As this plasma treatment, atmospheric pressure plasma treatment performed under atmospheric pressure is preferable. The surface treatment condition is not particularly limited as long as the mass concentration ratio O/S on the surface of the insulating layer 12 is 0.2 or more. When plasma treatment is performed as the surface treatment, for example, nitrogen or air can be used as the gas blown onto the surface of the insulating layer 12, but nitrogen is preferable. This is because, when nitrogen is supplied, active functional groups can be efficiently introduced to the surface of the insulating layer 12 and the mass concentration ratio O/S can be easily increased, as compared with the case of supplying air. Further, the plasma treatment time is preferably 0.2 seconds to 0.6 seconds. In the surface modification step S40, the surface treatment may be performed under the condition that the mass concentration ratio O/S is 0.2 or more in the depth range from the surface of the insulating layer 12 to at least 20 μm.

When the plasma processing apparatus is used as the surface processing apparatus 105, the atmospheric pressure plasma irradiation nozzle is arranged, but the arrangement is not particularly limited. For example, two atmospheric pressure plasma irradiation nozzles may be arranged so as to sandwich the flat conductor 11 on which the insulating layer 12 is formed. Alternatively, for example, a plurality of atmospheric pressure plasma irradiation nozzles may be arranged along the flat conductor 11. Good.

(Transportation step S50)
Subsequently, in a carrying step S50, in order to form the fusion bonding layer 13 on the surface-modified insulating layer 12, the insulated wire 10 is carried to the second extruder 106 and introduced.

In the carrying step S50, it is preferable that the insulating layer 12 activated by the surface modification is carried so that the elapsed time from the surface modifying step S40 to a fusion layer forming step S60 described later is shortened so that the insulating layer 12 is not deactivated. .. Specifically, the elapsed time is preferably 10 seconds or less. That is, it is preferable to convey the insulated wire 10 such that the fusion layer formation step S60 is performed within 10 seconds after the surface modification step S40. Since the effect of the surface modification is deactivated over time, if the time from the surface modification to the formation of the fusion layer 13 is long, the effect of the surface modification may be reduced. Then, it becomes difficult to maintain the mass concentration ratio O/S on the surface of the insulating layer 12 at 0.2 or more, and even if the fusion layer 13 is formed, sufficient adhesion with the insulating layer 12 may not be secured. is there. On the other hand, by conveying so that the elapsed time is 10 seconds or less, the adhesion between the insulating layer 12 and the fusion bonding layer 13 can be maintained high.

When the fusible insulated electric wire 1 is continuously manufactured as in the present embodiment, the elapsed time may be shortened by increasing the transportation speed. When the transport speed is increased, the amount of surface treatment per unit area of the surface of the insulating layer 12 is reduced, and the mass concentration ratio O/S tends to be small. In such a case, for example, a plasma irradiator is added. It is advisable to increase the surface treatment area for treatment.

(Fusing layer forming step S60)
Subsequently, as the fusion layer forming step S60, the outer periphery of the insulating layer 12 is extruded and coated with the fusible resin composition in the second extruder 106. The extruding temperature of the fusible resin composition may be a temperature equal to or higher than the melting point of the fusible thermoplastic resin. Then, it is introduced into the second cooling device 107 to cool the fusible resin composition to room temperature to form the fusible layer 13. In this embodiment, since the mass concentration ratio O/S on the surface of the insulating layer 12 is 0.2 or more for activation, the fusion bonding layer 14 can be formed on the insulating layer 12 with good adhesiveness. Thereby, the fusible insulated electric wire 1 of the present embodiment is obtained.

Finally, the fusible insulated electric wire 1 is wound by a bobbin by a winder 109 through a winder 108. In this way, the fusible insulated wire 1 can be manufactured.

[Coil and manufacturing method thereof]
Next, a coil manufactured using the above-mentioned fusible insulated wire 1 will be described.
For example, the coil is formed by winding the fusible insulated electric wire 1 into a coil having a predetermined shape, and then heating the fused fusible insulated wire 1 to melt the fusion layer 13 on the surface of the fusible insulated electric wire 1 to form an adjacent fusion bond. It can be manufactured by bonding and solidifying the electrically insulated wires 1.
The coil manufactured using the fusible insulated electric wire 1 has high adhesion between the fusible layer 13 and the insulating layer 12, and the adjacent insulated electric wires 10 are preferably fused. Therefore, the coil can maintain the coil shape for a long period of time, and has excellent insulation reliability.

<Effects of this embodiment>
According to this embodiment, one or more of the following effects are exhibited.

In the fusible insulated electric wire 1 of the present embodiment, the surface of the insulating layer 12 containing the PPS resin that is in contact with the fusible layer 13 is subjected to plasma treatment, so that the -OH group, the -SO group, the -SO ₂ group are added to the PPS resin. By introducing an active functional group such as, the mass concentration ratio O/S of oxygen O to sulfur S on the surface of the insulating layer 12 is 0.2 or more, preferably 0.2 or more and 0.5 or less. .. Thereby, high adhesion can be realized between the insulating layer 12 containing the PPS resin and the fusion bonding layer 13. Therefore, according to the fusible insulated wire 1 of the present embodiment, when processed into a coil, a high partial discharge inception voltage (PDIV) is realized by the PPS resin, and the coil shape is maintained to obtain high reliability. be able to.

In the fusible insulated electric wire 1, the thickness of the insulating layer 12 is preferably 160 μm to 240 μm. With such a thickness, a high PDIV can be realized, and when the fusible insulated electric wire 1 is bent to produce a coil, the insulating layer 12 can follow the bending deformation of the conductor 11. It is possible to maintain the high adhesion of the insulating layer 12 to the conductor 11.

Further, it is preferable that the resin composition forming the insulating layer 12 contains silicone rubber, and contains the PPS resin and the silicone rubber in a mass ratio of 90:10 to 98:2. By blending the silicone rubber in the above ratio, the adhesion of the insulating layer 12 to the conductor 11 can be improved without deteriorating the inherent properties of the PPS resin.

The crystallinity of the insulating layer 12 is preferably 95% or more. By setting the crystallinity to 95% or more, it is possible to improve various properties such as insulation, abrasion resistance, chemical resistance, and oil resistance in the insulating layer 12.

Further, in the fusible insulated wire 1, by forming the insulating layer 12 with the resin composition containing the PPS resin, the melted resin composition can be extruded to a desired thickness. Can be formed uniformly.

<Other Embodiments of the Present Invention>
Although one embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment and can be appropriately modified without departing from the scope of the invention.

In the above-described embodiment, the case where the insulating layer 12 is irradiated with plasma to perform the surface treatment in the surface modification step S40 has been described, but the present invention is not limited to this. For example, the insulating layer 12 may be irradiated with ultraviolet rays to be surface-treated.

Moreover, although the said embodiment demonstrated the case where the fusion bonding layer 13 was formed by extruding the fusion bonding resin composition containing a thermoplastic resin as a fusion bonding resin, this invention is not limited to this. For example, the fusing layer 13 may be formed by applying a paint containing a fusing resin composition to the outer periphery of the surface-modified insulating layer 12 and baking it. In this case, a thermosetting resin such as an epoxy resin or an unsaturated polyester resin may be used as the fusible resin.

Further, in the above-described embodiment, the fusible insulated electric wire 1 including the fusible layer 13 is used when manufacturing the coil, but the present invention is not limited to this. For example, the insulated electric wire 10 obtained in the surface modification step S40 is wound, the wound insulated electric wire 10 is coated with a coating material containing an adhesive resin composition, and this is baked to solidify, thereby adjoining each other. A coil may be manufactured by fusing the insulated wires 10 with a fusing layer.

Moreover, although the case where the insulating layer 12 is directly provided on the surface of the conductor 11 has been described in the above-described embodiment, the present invention is not limited to this. For example, one or more intermediate layers containing a resin selected from polyamideimide resin, polyimide resin, and polyesterimide resin may be provided between the conductor 11 and the insulating layer 12. The thickness of the intermediate layer may be, for example, 20 μm to 60 μm.

Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

<Production of fusible insulated wire>
(Example 1)
In Example 1, a fusible insulated wire having the structure shown in FIG. 1 was produced using the manufacturing apparatus 100 shown in FIG.
In Example 1, a rectangular copper wire was introduced into a preheating furnace and preheated to about 300° C. in a nitrogen atmosphere. Then, the heated rectangular copper wire was introduced into the first extruder, and as shown in Table 1, a resin composition obtained by kneading 95 parts by mass of PPS resin and 5 parts by mass of silicone rubber was prepared as rectangular copper. The outer circumference of the wire was extrusion-coated so that the average thickness was 0.16 mm (160 μm). Then, the extrusion-coated resin composition was cooled to about 200° C., which is the crystallization temperature of the PPS resin, in the first cooling device. Then, while the rectangular copper wire extrusion-coated with the resin composition was conveyed from the first cooling device to the plasma processing device, crystallization of the PPS resin was promoted to form an insulating layer having an average thickness of 160 μm. Then, the surface of the insulating layer was subjected to plasma treatment for 0.23 seconds in a plasma processing apparatus to modify the surface of the insulating layer to obtain an insulated wire. After that, it was introduced into the second extruder within 10 seconds, and an average of the fusible resin composition obtained by mixing 99 parts by mass of the phenoxy resin and 1 part by mass of the curing agent on the surface of the surface-modified insulating layer. By extrusion coating with a thickness of 0.04 mm (40 μm) and cooling with a second cooling device, a fusion layer having a thickness of 40 μm was formed. Thereby, the fusible insulated electric wire of Example 1 was obtained. In addition, in this example, as the rectangular copper wire, a wire having a rectangular cross section with a long side of about 3.2 mm and a short side of about 1.5 mm was used. The production conditions are shown in Table 1 below.

(Example 2)
In Example 2, as shown in Table 1, the fusion property was the same as in Example 1 except that the thickness of the insulating layer was changed to 0.24 mm (240 μm) and the plasma treatment time was changed to 0.55 seconds. An insulated wire was produced.

(Example 3)
In Example 3, as shown in Table 1, a coating material containing 100 parts by mass of an epoxy resin was applied to the surface of the insulating layer and baked to form a fusion layer having an average thickness of 0.02 mm (200 μm). A fusion-bondable insulated electric wire was produced in the same manner as in Example 1 except that the above was performed.

(Example 4)
In Example 4, as shown in Table 1, a fusible insulated wire was produced in the same manner as in Example 1 except that the thickness of the insulating layer was changed to 0.35 mm (350 μm).

(Comparative Example 1)
In Comparative Example 1, a fusible insulated wire was produced in the same manner as in Example 1 except that plasma treatment was not performed.

(Comparative example 2)
In Comparative Example 2, a fusible insulated wire was produced in the same manner as in Example 3 except that plasma treatment was not performed.

(Comparative Examples 3 and 4)
In Comparative Examples 3 and 4, fusion bonding was performed in the same manner as in Example 3 except that the insulating layer was formed by applying and baking a coating material containing 100 parts by mass of a polyamideimide resin instead of extruding the resin composition containing the PPS resin. An electrically insulated wire was produced.

<Evaluation method>
The fusible insulated wires of Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated by the following methods.

(Mass concentration ratio O/S)
The mass concentration ratio O/S of oxygen O to sulfur S on the surface of the insulating layer is 10 μm at a depth of 20 μm from the interface with the fusion layer in the insulation layer in a cross section perpendicular to the longitudinal direction of the fusible insulated wire. Elemental analysis was performed on the four regions by EDX, and the mass concentration ratio O/S of oxygen O to sulfur S was calculated. The X-ray output was 7 kV.

(Adhesive strength after fusion)
First, a test piece for measuring the adhesive force after fusion bonding was prepared.
Specifically, first, the fusible insulated wire was cut into a length of 40 cm, and the outer surface of the fusible layer was washed with ethyl alcohol to remove the oil film and the like. Subsequently, the fusible insulated wire was stretched 5% to be flat, and cut into a length of 10 cm to prepare four samples. The four samples were arranged as shown in FIG. 5 with reference to the fixing force (Stracker method) at room temperature specified in Annex JC of JIS C 2103:2013. FIG. 5 is a perspective view of a test piece for evaluating the adhesive strength of the fusible insulated wire after fusing. As shown in FIG. 5, after arranging the four samples 51, each sample 51 is temporarily fixed with an adhesive tape so as not to be displaced, and is pressed from the vertical direction shown in FIG. Heated. Thereby, each sample 51 was fused and the test piece 50 was produced.
Subsequently, with respect to the test piece 50, the adhesive force after fusion bonding was measured with reference to the varnish test method for electrical insulation described in JIS C 2103:2013.
Specifically, both ends of the test piece 50 shown in FIG. 5 were grasped by an autograph clamp and pulled at a speed of 5 m/min, and the maximum tensile strength at which the adhesion of each sample 51 was broken was measured. Then, the shear adhesive strength (maximum tensile strength/coated contact area) of the insulating layer and the fusion bonding layer was obtained from the maximum tensile strength with respect to the coated contact area (100 mm×3.2 mm×2) of the test piece shown in FIG. The shear adhesive strength at this time was evaluated as ◯ when it was 1.5 N/mm ² or more, and as x when it was less than 1.5 N/mm ² .

(Electrical insulation)
Two insulated electric wires before the provision of the fusion bonding layer were prepared, and the insulating layers on the long sides were adhered to each other so that there was no gap over a length of 150 mm to prepare a sample. The voltage at which 50 pC partial discharge is generated 50 times or more while measuring the voltage between the two conductors of this sample with an alternating current of 50 Hz at 10 V/s, and the voltage of 1550 V or more is ◯ and less than 1550 V. The thing was marked as x.

(Insulation layer thickness uniformity)
Embed the fusible insulated wire in epoxy resin and polish the cross-section along a plane perpendicular to the longitudinal direction of the fusible insulated wire to obtain a cross section perpendicular to the longitudinal direction of the fusible insulated wire. The thickness of the insulating layer 12 was measured at two places, two at the center of the short side, and four at the corners, and the average value was calculated. When all the differences between the thicknesses at the eight locations and the average value were less than 10% of the average value, the result was ◯.

<Evaluation result>
The evaluation results are shown in Table 1 above.

In Examples 1 to 4, the mass concentration ratio O/S on the surface of the insulating layer was 0.2 or more, and the active functional group could be sufficiently introduced to the surface of the insulating layer containing the PPS resin. It was confirmed that the adhesiveness between the adhesive layer and the fusion layer was high and the adhesive force after fusion was good.
In addition, in all of Examples 1 to 4, since the insulating layer was formed by extruding a resin composition containing a PPS resin, it was confirmed that the electrical insulating property and the uniformity of the thickness of the insulating layer were good. It was

On the other hand, in Comparative Examples 1 and 2, since the insulating layer containing the PPS resin was not surface-modified by plasma treatment, the mass concentration ratio O/S on the surface of the insulating layer was as small as less than 0.2, and fusion with the insulating layer It was confirmed that the adhesion to the layer was low. It is considered that this is because the insulating layer containing the PPS resin is chemically stable and has a low chemical affinity with the phenoxy resin or the epoxy resin forming the fusion bonding layer.

In Comparative Example 3, by forming the insulating layer of the polyamide-imide resin instead of the PPS resin, high adhesion was obtained between the fusion bonding layer and the insulating layer, but the electrical insulating property was insufficient. Was confirmed. This is because the relative dielectric constant of the polyamide-imide resin is higher than that of the PPS resin, and when the polyamide-imide resin is used to form the insulating layer with a thickness similar to that of the PPS resin, sufficient electrical insulation is obtained. It is considered that it is not possible to obtain.
In Comparative Example 4, the insulating layer was formed of polyamide-imide resin as in Comparative Example 3 and the thickness thereof was set to 0.16 mm, which was thicker than that of Comparative Example 3. However, the thickness of the insulating layer varied in the circumferential direction, It was confirmed that it was not uniform. In addition, it was confirmed that the electrical insulating property was also reduced because the thickness of the insulating layer was non-uniform.
In addition, in Comparative Example 3 and Comparative Example 4, since the polyamide-imide resin containing no S was used for the insulating layer, the mass concentration ratio O/S was not calculated and was represented as “−”.

As described above, even if the insulating layer contains the PPS resin and is chemically stable and has a low chemical affinity with other substances, the mass concentration ratio O/S on the surface of the insulating layer is 0 due to the surface modification. By setting the ratio to 2 or more, the chemical affinity with the fusible resin can be increased and the adhesion between the insulating layer and the fusible layer can be improved.

<Preferred embodiment of the present invention>
Hereinafter, the preferred embodiments of the present invention will be additionally described.

[Appendix 1]
According to one aspect of the invention,
A conductor,
An insulating layer disposed on the outer periphery of the conductor, the insulating layer comprising a resin composition containing a polyphenylene sulfide resin,
There is provided an insulated wire in which the insulating layer is formed so that the mass concentration ratio O/S of oxygen O to sulfur S on the surface is 0.2 or more.

[Appendix 2]
In the insulated wire of Appendix 1, preferably,
The resin composition forming the insulating layer contains silicone rubber, and contains the polyphenylene sulfide resin and the silicone rubber in a mass ratio of 90:10 to 98:2.

[Appendix 3]
In the insulated wire of Supplementary Note 1 or 2, preferably
The insulating layer has a crystallinity of 95% or more.

[Appendix 4]
In the insulated wire according to any one of appendices 1 to 3, preferably,
The insulating layer has a thickness of 160 μm or more and 240 μm or less.

[Appendix 5]
According to another aspect of the invention,
There is provided a fusible insulated electric wire comprising the insulated electric wire according to any one of appendices 1 to 4, comprising a fusible layer made of a fusible resin composition on the outer periphery of the insulating layer.

[Appendix 6]
According to another aspect of the invention,
A coil in which an insulated electric wire is wound, and the adjacent insulated electric wires are fused by a fusion layer made of a fusible resin composition,
The insulated wire is
A conductor and an insulating layer disposed on the outer periphery of the conductor and made of a resin composition containing a polyphenylene sulfide resin,
A coil is provided, wherein the insulating layer has a mass concentration ratio O/S of oxygen O to sulfur S of 0.2 or more on the surface in contact with the fusion layer.

[Appendix 7]
According to another aspect of the invention,
An insulating layer forming step of forming an insulating layer made of a resin composition containing a polyphenylene sulfide resin on the outer periphery of the conductor;
And a surface modification step of modifying the surface of the insulating layer so that the mass concentration ratio O/S of oxygen O to sulfur S on the surface of the insulating layer becomes 0.2 or more. To be done.

[Appendix 8]
In the method for producing an insulated wire according to Appendix 7, preferably,
In the surface modification step, the surface of the insulating layer is irradiated with at least one of plasma and ultraviolet rays.

[Appendix 9]
According to another aspect of the invention,
After forming an insulated wire by the method for producing an insulated wire according to appendix 7 or 8, a fused layer is formed on the outer periphery of the surface-modified insulating layer, the fused layer comprising a fusible resin composition. Provided is a method for manufacturing a fusible insulated wire, which has steps.

[Appendix 10]
In the method for producing a fusible insulated wire of Supplementary Note 9, preferably,
The fusion layer formation step is performed within 10 seconds after the surface modification step.

[Appendix 11]
According to another aspect of the invention,
An insulating layer forming step of forming an insulating layer made of a resin composition containing a polyphenylene sulfide resin on the outer periphery of the conductor;
A surface modification step of modifying the surface of the insulating layer so that the mass concentration ratio O/S of oxygen O to sulfur S on the surface of the insulating layer becomes 0.2 or more to obtain an insulated wire;
On the outer periphery of the surface-modified insulating layer, a fusion layer forming step of forming a fusion layer made of a fusion resin composition to obtain a fusion insulated wire,
A winding step of winding the fusible insulated wire,
The present invention provides a method for manufacturing a coil, which comprises a fusion step of fusion-bonding the adjacent fusible insulated wires by winding at the fusion layer.

1 Fusing Insulated Electric Wire 10 Insulated Electric Wire 11 Conductor 12 Insulating Layer 13 Fusing Layer

Claims (5)

A conductor,
An insulating layer, which is arranged on the outer periphery of the conductor and is made of a resin composition containing a polyphenylene sulfide resin,
A fusible layer made of a fusible resin composition containing a thermoplastic resin on the outer periphery of the insulating layer ,
The insulating layer is a fusible insulated electric wire in which a mass concentration ratio O/S of oxygen O to sulfur S on the surface is 0.2 or more and 0.5 or less . The melt according to claim 1, wherein the resin composition forming the insulating layer contains a silicone rubber, and contains the polyphenylene sulfide resin and the silicone rubber in a mass ratio of 90:10 to 98:2. Adhesive insulated wire. The fusible insulated electric wire according to claim 1, wherein the insulating layer has a crystallinity of 95% or more. The thickness of the insulating layer is less 240μm least 160 .mu.m, bonding insulated wire according to claim 1. An insulating layer forming step of forming an insulating layer made of a resin composition containing a polyphenylene sulfide resin on the outer periphery of the conductor;
A surface modification step of modifying the surface of the insulating layer such that the mass concentration ratio O/S of oxygen O to sulfur S on the surface of the insulating layer is 0.2 or more and 0.5 or less ;
The outer periphery of the surface modified the insulating layer, the manufacturing method of bonding insulated wire having a bonding layer forming step of forming a fusion bonded layer comprising a fusible resin composition comprising a thermoplastic resin.