JP6503993B2 - Insulated wire and method of manufacturing the same - Google Patents

Description

  The present invention relates to an insulated wire and a method of manufacturing the same.

  A coil is incorporated in an electric device such as a rotating electric machine (motor) or a transformer. The coil is formed by winding an insulated wire in which an insulating layer is formed on the outer periphery of a conductor. The insulated wire can be coated and baked on the outer periphery of the conductor with an insulating paint in which the resin component is dissolved in an organic solvent, a method of extruding the molten resin on the outer periphery of the conductor, or by using these methods in combination. , And an insulating layer formed on the outer periphery of the conductor.

  In recent years, due to the demand for miniaturization of electric devices, coils are manufactured by winding insulated wires around a small core with high tension and high density. Therefore, the insulating layer is required to have high mechanical properties (for example, adhesion, wear resistance, etc.) that can withstand severe processing stress.

  In addition, electric devices are driven with a high current in response to a demand for higher output, and the operating temperature of the coil tends to be higher than before. Therefore, high heat resistance is required for the insulating layer.

  Furthermore, in the electric apparatus, inverter control has been developed due to the demand for higher efficiency, and higher voltage such as inverter surge voltage is applied to the coil, and partial discharge is likely to occur. If partial discharge occurs, the insulating layer may be degraded or damaged. Therefore, the insulating layer is required to have a high partial discharge inception voltage and excellent electrical characteristics so that partial discharge does not occur at a low voltage. It is done.

  As a resin for forming such an insulating layer, polyphenylene sulfide resin (hereinafter, also referred to as PPS resin) which is excellent in mechanical characteristics, heat resistance and electrical characteristics is used. PPS resin generally has high crystallinity and can not obtain sufficient adhesion with a conductor, so the following methods have been proposed as a method for improving the adhesion of an insulating layer made of PPS resin . For example, Patent Document 1 proposes a method of forming an insulating layer by extruding a PPS resin onto a conductor via a resin layer made of another resin. For example, in patent document 2, when extruding PPS resin on the outer periphery of a conductor, the method of preheating a conductor to the temperature more than the melting point of PPS resin is proposed previously.

Patent No. 4177295 gazette JP 2014-103045 A

  By the way, when producing coils, such as a motor, using an insulated wire, the end of a short insulated wire may be welded, it may be connected together, it may be formed in a long length, and it may produce in a coil. Generally as welding, electric welding, such as TIG welding, is performed, and the temperature of a welding part is raised by supplying a fixed electric current, and conductors are connected.

  However, in the insulated wire in which the insulating layer made of PPS resin is provided on the outer periphery of the conductor directly or through another resin layer as in Patent Documents 1 and 2, the heat resistance of the insulating layer and the adhesion with the conductor Since it is insufficient, the heat transmitted from the conductor when welded may cause the insulating layer to foam or peel off in the vicinity of the weld. In particular, when the insulating layer is crystallized to increase the degree of crystallization from the viewpoint of solvent resistance, in the insulating layer, internal distortion becomes large due to volume contraction accompanying crystallization, and adhesion is lowered. It becomes easy to do.

  The present invention has been made in view of the above problems, and is excellent in mechanical properties, heat resistance, electrical properties and solvent resistance, and has insulation resistance having welding resistance such that the insulating layer is not easily peeled off at the time of welding. The purpose is to provide a wire.

According to one aspect of the invention:
With a conductor,
An inner layer covering the outer periphery of the conductor and an insulating layer having an outer layer covering the outer periphery of the inner layer;
The inner layer is formed from a resin composition (A) containing a polyetheretherketone resin,
The outer layer is formed of a resin composition (B) containing a polyphenylene sulfide resin,
An insulated wire is provided, wherein the crystallinity of each of the inner layer and the outer layer is 95% or more.

According to another aspect of the invention,
A first coating step of extruding and coating a resin composition (A) containing a polyetheretherketone resin on the outer periphery of a conductor;
An inner layer forming step of curing the resin composition (A) to form an inner layer;
A second coating step of extruding and coating a resin composition (B) containing a polyphenylene sulfide resin on the outer periphery of the inner layer;
An outer layer forming step of curing the resin composition (B) to form an outer layer;
In the inner layer forming step, the resin composition (A) is heat treated at a temperature between the recrystallization temperature and the melting point to recrystallize the inner layer to a crystallinity of 95% or more,
In the outer layer forming step, the method for producing an insulated wire, wherein the crystallization degree of the outer layer is made 95% or more by heat-treating the resin composition (B) at a temperature between the recrystallization temperature and the melting point to recrystallize it. Is provided.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in mechanical characteristics, heat resistance, an electrical property, and solvent resistance, and the insulated wire which has welding resistance which an insulating layer does not peel easily at the time of welding is obtained.

It is a perspective view which shows the cross section of the insulated wire which concerns on one Embodiment of this invention. It is the schematic of the manufacturing apparatus which manufactures the insulated wire which concerns on one Embodiment of this invention.

  As described above, when the insulated wire is elongated by welding, the resin layer (PPS resin layer) made of polyphenylene sulfide resin provided on the outer periphery of the conductor may be peeled off by heat transmitted through the conductor. There is a need to improve sexuality. Then, the present inventors examined PPS resin layer, providing a conductor through a resin layer excellent in heat resistance. As a result, they have found that the resin layer to be interposed is formed of a polyetheretherketone resin (hereinafter also referred to as PEEK resin) having a melting point higher than that of PPS resin, and the crystallinity degree is preferably 95% or more. By forming the insulating layer in this manner, it is possible to suppress the influence of heat transfer at the time of welding and to suppress the foaming and peeling of the insulating layer at the portion in contact with the conductor.

  The present invention has been made based on the above findings.

<Schematic Configuration of Insulated Wire>
Hereinafter, an insulated wire according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a cross section of an insulated wire according to an embodiment of the present invention.

  As shown in FIG. 1, the insulated wire 1 according to the present embodiment includes a conductor 11, an inner layer 12 covering the outer periphery of the conductor 11, and an insulating layer 14 having an outer layer 13 covering the outer periphery of the inner layer 12. There is.

  The conductor 11 is not particularly limited as long as it contains copper as a main component. For example, a copper wire made of low-oxygen copper or oxygen-free copper or a copper alloy wire containing a metal other than copper can be used. . The cross-sectional shape of the conductor 11 is not limited to the substantially rectangular shape shown in FIG. 1 and may be, for example, a circular shape or an elliptical shape. From the viewpoint of increasing the ratio of the conductor component to the insulated wire 1 and improving the space factor in the coil, it is preferable to use a substantially rectangular shape as the conductor 11.

  The insulating layer 14 has an inner layer 12 and an outer layer 13.

  The inner layer 12 is located on the conductor 11 side. In the present embodiment, from the viewpoint of improving the welding resistance of the insulated wire 1, the inner layer 12 in contact with the conductor 11 is formed of a resin composition (A) containing a PEEK resin. Thus, the heat resistance of the inner layer 12 is improved, and the inner layer 12 is configured to be difficult to melt due to heat transfer at the time of welding.

  In the resin composition (A) for forming the inner layer 12, if necessary, another resin other than the PEEK resin, an antioxidant, a colorant and the like may be blended. Other resins include, for example, polyphenylene sulfone, olefin copolymer resin, maleic anhydride, glycidyl methacrylate, syndiotactic polystyrene, polyimide, polyamide, polyamide imide, thermoplastic polyimide, polyether imide, polymethyl pentene, poly Butylene terephthalate, polybutylene naphthalate, polyethylene, polystyrene, or mixtures thereof can be used. These compounding amounts can be suitably changed in the range which does not impair the effect of this invention.

The crystallinity of the inner layer 12 is 95% or more. When the degree of crystallinity is less than 95%, the heat resistance of the inner layer 12 is lowered, and the heat transfer at the time of welding causes the inner layer 12 to be easily foamed or peeled off, so that the welding resistance is also lowered. In the present specification, the degree of crystallinity is defined as follows. That is, when the heat of crystallization at the time of cold crystallization measured while raising the temperature by differential scanning calorimetry is Hc, and the heat of fusion by differential scanning calorimetry is Hm, the crystallization degree α is represented by the following formula (1).
Degree of crystallinity α = (1-Hc / Hm) × 100 (1)

  The inner layer 12 preferably has a thickness of 40 μm or more from the viewpoint of obtaining desired high welding resistance. On the other hand, from the viewpoint of obtaining sufficient adhesion with the conductor 11, the thickness of the inner layer 12 is preferably at least 150 μm or less. When the inner layer 12 is formed by crystallizing the resin composition (A) containing the PEEK resin, the inner layer 12 is deformed by volume contraction of crystallization, but the thickness is made 150 μm or less. The amount of deformation can be reduced to reduce internal strain in the inner layer 12. As a result, the inner layer 12 can be formed in a state of high adhesion to the conductor 11.

  The outer layer 13 is disposed on the outer periphery of the inner layer 12. In the present embodiment, the outer layer 13 is formed of a resin composition (B) containing a PPS resin. Therefore, the outer layer 13 has desired high mechanical properties, heat resistance and electrical properties. Moreover, since the outer layer 13 is configured to have a crystallinity of 95% or more, the outer layer 13 is also excellent in solvent resistance.

  In the resin composition (B) for forming the outer layer 13, another resin other than the PPS resin, an antioxidant, a coloring agent, and the like may be blended, as necessary. As other resin, the same resin as the resin compounded to the resin composition (A) which forms the inner layer 12 listed above can be used.

  The thickness of the outer layer 13 is not particularly limited. However, when the crystallinity of the outer layer 13 is increased when it is excessively large, internal strain caused by volume contraction accompanying crystallization increases and adhesion to the inner layer 12 is increased. It may decrease. Therefore, the thickness of the outer layer 13 is preferably 1 μm or more and 150 μm or less. The total thickness of the inner layer 12 and the outer layer 13 is preferably 150 μm or more from the viewpoint of obtaining a partial discharge inception voltage of 1550 V or more.

<Method of manufacturing insulated wire>
Next, a method of manufacturing the above-described insulated wire will be described with reference to the drawings. FIG. 2 is a schematic view of a manufacturing apparatus for manufacturing an insulated wire according to an embodiment of the present invention.

  As shown in FIG. 2, the manufacturing apparatus 100 includes a delivery device 110, a pulley 120, a preheating device 130, a first extruder 140, a first cooling device 141, a second extruder 150, and a second device 150. A cooling device 151, a third cooling device 160, a take-up device 170, and a winding device 180 are provided.

  In the method of manufacturing the insulated wire 1 of the present embodiment, a preheating step S10 of preheating the conductor 11, and a process of extruding and coating a resin composition (A) containing PEEK resin on the outer periphery of the heated conductor 11 A second covering step S20, an inner layer forming step S30 for curing the resin composition (A) to form the inner layer 12, and an outer periphery of the inner layer 12 by extruding and covering the resin composition (B) containing PPS resin And an outer layer forming step S50 of curing the resin composition (B) to form the outer layer 13.

(Preheating process S10)
First, as shown in FIG. 2, a conductor 11 having a substantially rectangular cross section (hereinafter, also simply referred to as a flat rectangular conductor 11) is introduced from the feeder 110 through the pulley 120 to the preheating device 130.

  In the preheating device 130, the flat rectangular conductor 11 is preheated to a temperature equal to or higher than the melting point of the PEEK resin contained in the resin composition (A) extruded in the first covering step S20 described later. When it is lower than the melting point of PEEK resin, when the molten high temperature resin composition (A) is extruded on the outer periphery of the flat conductor 11, the resin composition (A) is cooled and cured by contact with the flat conductor 11 Therefore, cooling and curing can not be performed in a state of being in close contact with the rectangular conductor 11 sufficiently. As a result, the adhesion between the inner layer 12 and the conductor 11 obtained by cooling may be impaired. On the other hand, before extrusion coating of the resin composition (A), cooling and curing of the resin composition (A) by contact with the rectangular conductor 11 is performed by heating the rectangular conductor 11 to a temperature equal to or higher than the melting point. Can be suppressed, and the inner layer 12 having high adhesion can be formed.

  The temperature for preheating the rectangular conductor 11 is not particularly limited as long as it is a temperature equal to or higher than the melting point of the PEEK resin. For example, it is preferable to make the flat angle conductor 11 into 380 degreeC or more and 420 degrees C or less. With such a preheating temperature, when the resin composition (A) containing the PEEK resin is extruded to the outer periphery of the flat conductor 11, the resin composition (A) is coated without being cooled or foamed. can do.

  In the preheating device 130, it is preferable to replace the inside of the device with an inert gas, and to preheat the rectangular conductor 11 in an inert gas atmosphere. When the flat conductor 11 is heated to a high temperature state, it is likely to be oxidized, and the adhesion of the inner layer 12 may be greatly reduced. In this respect, by preheating the rectangular conductor 11 in an inert gas atmosphere, the rectangular conductor 11 can be heated to a predetermined temperature without being oxidized. Note that, as the inert gas, for example, general-purpose low-cost nitrogen, helium excellent in thermal conductivity, or the like can be used.

(First covering step S20)
Subsequently, the heated flat conductor 11 is conveyed from the preheating device 130 to the first extruder 140. In the first extruder 140, the resin composition (A) containing PEEK resin is extruded and coated on the outer periphery of the heated flat conductor 11.

(Inner layer forming step S30)
Subsequently, the flat conductor 11 coated with the resin composition (A) is conveyed to the first cooling device 141. The molten resin composition (A) is cooled by the first cooling device 141 to form the inner layer 12. At this time, the crystallization of the inner layer 12 is promoted, and the resin composition (A) containing the PEEK resin is cooled so that the degree of crystallinity is 95% or more. Specifically, after quenching the resin composition (A) containing the PEEK resin to a temperature below the melting point of the PEEK resin (for example, 380 ° C.) and to the temperature at which the PEEK resin crystallizes, the PEEK resin has a crystallization temperature It is preferable to keep (for example, 300 ° C.). Thereby, the crystallization of the PEEK resin can be promoted, and the crystallinity of the PEEK resin in the obtained inner layer 12 can be raised to 95% or more. Then, when the predetermined degree of crystallinity is reached, the crystallization is stopped by cooling to a temperature lower than the crystallization temperature of the PEEK resin, and the inner layer 12 having the predetermined degree of crystallinity is formed. In addition, as a cooling method, the method of water-cooling with a water tank etc. is mentioned.

(2nd covering process S40)
Subsequently, the flat conductor 11 having the inner layer 12 formed on the surface is transported to the second extruder 150. In the second extruder 150, the resin composition (B) containing PPS resin is extruded and coated on the outer periphery of the inner layer 12.

(Outer layer forming step S50)
Subsequently, the flat conductor 11 coated with the resin composition (B) is transported to the second cooling device 151. The molten resin composition (B) is cooled by the second cooling device 151 to form the outer layer 13. At this time, the crystallization of the outer layer 13 is promoted, and the resin composition (B) containing the PPS resin is cooled so that the degree of crystallization is 95% or more. Specifically, the resin composition (B) containing a PPS resin is quenched to a temperature below the melting point of the PPS resin (for example 280 ° C.) and to a temperature at which the PPS resin crystallizes, and then the crystallization temperature of the PPS resin It is preferable to keep (for example, 200 ° C.). Thereby, the crystallization of the PPS resin can be promoted, and the degree of crystallization of the PPS resin in the obtained outer layer 13 can be increased to 95% or more. Then, when the crystallization degree is reached, the crystallization is stopped by cooling to a temperature lower than the crystallization temperature of the PPS resin, and the outer layer 13 having the crystallization degree is formed. In addition, as a cooling method, the method of water-cooling with a water tank etc. are mentioned similarly to said inner-layer formation process S30.

  By the steps described above, the insulated wire 1 in which the insulating layer 14 having the inner layer 12 and the outer layer 13 is formed on the outer periphery of the conductor 11 is manufactured. After the insulated wire 1 is cooled to normal temperature by the third cooling device 160, the insulated wire 1 is pulled out at a predetermined linear velocity by the pulling machine 170 and taken up by the winding machine 180.

  In the present embodiment, in the inner layer forming step S30 and the outer layer forming step S50, after quenching to a temperature less than the melting point of the PEEK resin or PPS resin, the crystallization temperature is maintained. Although the degree of crystallinity is increased, the present invention is not limited thereto. For example, after quenching the inner layer 12 and the outer layer 13 to a temperature lower than the crystallization temperature, the crystallization may be promoted by heating again to a temperature range higher than the crystallization temperature and lower than the melting point.

  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 insulated wire]
Example 1
Insulated wires were produced under the conditions shown in Table 1 below.
Specifically, first, a flat copper wire having a long side of about 3 mm and a short side of about 2 mm and a substantially rectangular cross section was introduced into the preheating apparatus as a conductor. In the preheating apparatus, the flat copper wire was preheated in a nitrogen atmosphere until the conductor temperature reached 400.degree.
Subsequently, the heated flat copper wire was introduced into the first extruder. In the first extruder, PEEK resin was extrusion-coated on the outer periphery of the rectangular copper wire so that the extrusion temperature was 400 ° C. and the coating thickness was 40 μm. Thereafter, the PEEK resin was quenched for 0.5 seconds so that the temperature was 300 ° C. in the first cooling device, and then maintained at the crystallization temperature to promote crystallization. Thus, an inner layer of PEEK resin having a thickness of 40 μm and a crystallinity of 95% or more was formed.
Subsequently, the flat copper wire coated with the inner layer was introduced into the second extruder. In the second extruder, PPS resin was extrusion-coated on the outer periphery of the inner layer so that the extrusion temperature was 300 ° C. and the coating thickness was 110 μm. Thereafter, the PPS resin was quenched for 0.5 seconds so that the temperature was 200 ° C. in a second cooling device, and then maintained at the crystallization temperature to promote crystallization. Thereby, the outer layer which is 110 micrometers in thickness, and whose crystallinity degree is 95% or more and which consists of PPS resin was formed, and the insulated wire of Example 1 was produced.
Finally, the insulated wire was cooled to normal temperature by a third cooling device and wound up by a winder.

（比較例１）
比較例１では、絶縁層として、厚さ１５０μｍのＰＥＥＫ樹脂層を形成した以外は、実施例１と同様に絶縁電線を作製した。

(Comparative example 1)
In Comparative Example 1, an insulated wire was produced in the same manner as in Example 1 except that a PEEK resin layer having a thickness of 150 μm was formed as the insulating layer.

(Comparative example 2)
In Comparative Example 2, a 150 Pm-thick PPS resin layer is formed as an insulating layer by setting the preheating temperature of the rectangular copper wire to 300C and extruding the PPS resin at an extrusion temperature of 300C and a coating thickness of 150 m. The insulated wire was produced like Example 1 except having carried out.

(Comparative example 3)
In Comparative Example 3, when the PPS resin is extruded and then cooled to form the insulating layer, the cooling time is extended to 0.5 seconds to 5 seconds, and the insulated wire is cooled to room temperature without using the third cooling device. The insulated wire was produced like comparative example 2 except having carried out.

〔Evaluation method〕
About the produced insulated wire, it evaluated by the following methods.

(Welding resistance)
The insulation layer of the produced insulated wire is peeled off to about 5 mm from one end of the insulated wire, and the welding rod is brought into contact with the flat copper wire at a distance of 0.7 mm from the insulating layer, and TIG welding is performed for 0.1 seconds with a current of 140A. The After that, it was confirmed whether the insulating layer had a bubble or a swelling (lift). In this example, if foaming and swelling did not occur, the test was evaluated as “good” with excellent weld resistance, and if any of foaming and swelling occurred, it was judged as poor “poor” with poor solvent resistance. .

(Solvent resistance)
A test piece (sample) of 150 mm in length is taken from the produced insulated wire, and after immersing this sample in xylene at a temperature of 60 ° C. specified for JIS K8271 for 30 minutes, it is taken out and foaming or floating occurs in the insulating layer I checked to see if it was In this example, when foaming and swelling did not occur, the product was evaluated as "good" with excellent solvent resistance, and when either foaming or blistering occurred, it was determined as poor with "poor resistance" as "poor". .

〔Evaluation results〕
In Example 1, in the insulating layer having the inner layer and the outer layer, the PEEK resin excellent in heat resistance is used for the inner layer, and the degree of crystallization is made to be 95% or more. Therefore, it is confirmed that the welding resistance is excellent. It was done. Further, it was confirmed that the outer layer was made of PPS resin and had a crystallinity of 95% or more, so that it was also excellent in solvent resistance.

  On the other hand, in Comparative Example 1, only the PEEK resin layer was formed as the insulating layer, so it was confirmed that although it is excellent in welding resistance, it is inferior in solvent resistance. Further, in Comparative Example 2, only the PPS resin layer was formed as the insulating layer, so it was confirmed that although it is excellent in solvent resistance, it is inferior in welding resistance, probably because the heat resistance is low. Further, in Comparative Example 3, when cooling the PPS resin, the cooling time is extended to make the temperature of the PPS resin less than the recrystallization temperature, so that the degree of crystallization of the PPS resin layer is low and the solvent resistance is insufficient. It was confirmed that

<Preferred embodiment of the present invention>
The preferred embodiments of the present invention will be additionally described below.

[Supplementary Note 1]
According to one aspect of the invention:
With a conductor,
An inner layer covering the outer periphery of the conductor and an insulating layer having an outer layer covering the outer periphery of the inner layer;
The inner layer is formed from a resin composition (A) containing a polyetheretherketone resin,
The outer layer is formed of a resin composition (B) containing a polyphenylene sulfide resin,
An insulated wire is provided, wherein the crystallinity of each of the inner layer and the outer layer is 95% or more.

[Supplementary Note 2]
In the insulated wire of appendix 1, preferably
The thickness of the inner layer is 40 μm or more and 150 μm or less.

[Supplementary Note 3]
Preferably, in the insulated wire of appendix 1 or 2,
The thickness of the outer layer is 150 μm or less.

[Supplementary Note 4]
According to another aspect of the invention,
A first coating step of extruding and coating a resin composition (A) containing a polyetheretherketone resin on the outer periphery of a conductor;
An inner layer forming step of curing the resin composition (A) to form an inner layer;
A second coating step of extruding and coating a resin composition (B) containing a polyphenylene sulfide resin on the outer periphery of the inner layer;
An outer layer forming step of curing the resin composition (B) to form an outer layer;
In the inner layer forming step, the resin composition (A) is heat treated at a temperature between the recrystallization temperature and the melting point to recrystallize the inner layer to a crystallinity of 95% or more,
In the outer layer forming step, the method for producing an insulated wire, wherein the crystallization degree of the outer layer is made 95% or more by heat-treating the resin composition (B) at a temperature between the recrystallization temperature and the melting point to recrystallize it. Is provided.

[Supplementary Note 5]
In the method for producing an insulated wire according to Appendix 4, preferably
Before the first coating step, the method further includes a preheating step of preheating the conductor to a temperature equal to or higher than the melting point of the resin composition (A).

1 Insulated wire 11 conductor (flat conductor)
12 inner layer 13 outer layer 14 insulating layer

Claims (5)

With a conductor,
An inner layer covering the outer periphery of the conductor and an insulating layer having an outer layer covering the outer periphery of the inner layer;
The inner layer is in contact with the conductor;
The inner layer is formed from a resin composition (A) containing a polyetheretherketone resin,
The outer layer is formed of a resin composition (B) containing a polyphenylene sulfide resin,
An insulated wire, wherein the crystallinity of each of the inner layer and the outer layer is 95% or more.   The insulated wire according to claim 1, wherein the thickness of the inner layer is 40 μm or more and 150 μm or less.   The insulated wire according to claim 1, wherein a thickness of the outer layer is 150 μm or less. A first coating step of extruding and coating a resin composition (A) containing a polyetheretherketone resin on the outer periphery of the conductor so as to contact the conductor ;
An inner layer forming step of curing the resin composition (A) to form an inner layer;
A second coating step of extruding and coating a resin composition (B) containing a polyphenylene sulfide resin on the outer periphery of the inner layer;
An outer layer forming step of curing the resin composition (B) to form an outer layer;
In the inner layer forming step, the resin composition (A) is heat treated at a temperature between the recrystallization temperature and the melting point to recrystallize the inner layer to a crystallinity of 95% or more,
In the outer layer forming step, the method for producing an insulated wire, wherein the crystallization degree of the outer layer is made 95% or more by heat-treating the resin composition (B) at a temperature between the recrystallization temperature and the melting point to recrystallize it. .   The manufacturing method of the insulated wire according to claim 4, further comprising a preheating step of preheating the conductor to a temperature equal to or higher than the melting point of the resin composition (A) before the first covering step.

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