JP2011103204A - Electric wire for submersible motor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric wire for a submersible motor, which is improved in peeling performance of a protective layer and improved in workability at the time of forming of a coil, while maintaining adhesion (water sealing performance) between an insulating coating layer and the protective layer, and preventing generation of water trees. <P>SOLUTION: The electric wire for a submersible motor 1 has a conductor shielding layer 3, the insulating coating layer 4, and the protective layer 5 formed in order on the outer circumference of a conductor 2. The insulating coating layer 4 contains fatty acid amide of 0.5 pts.mass or more and 5.0 pts.mass or less based on a resin of 100 pts.mass as a principal component. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric wire for an underwater motor used for a coil of an underwater motor used underwater and a manufacturing method thereof.

  An underwater motor electric wire in which an insulating coating layer is formed on the outer periphery of a conductor is used for a coil (winding) of the underwater motor. The electric wire for underwater motors is an electric wire intended to be used underwater as the name indicates.

  Conventionally, an underwater motor electric wire has a conductor shielding layer that prevents the precipitation and diffusion of copper ions on the outer periphery of the conductor, an insulating coating layer on the outer periphery of the conductor shielding layer, and an insulating coating layer on the outer periphery of the insulating coating layer. It is formed by forming a protective layer (jacket) that prevents external damage. The protective layer is often made of a polyamide resin in view of wear resistance, extrusion characteristics, and the like.

  When a gap exists at the interface between the protective layer and the insulating coating layer, and water penetrates into the gap, a water tree is likely to be generated. Therefore, it is desirable that the adhesion between the insulating coating layer and the protective layer is better.

JP-A-6-267334 Japanese Patent Laid-Open No. 3-273042 JP-A-4-126309 Japanese Patent Laid-Open No. 3-6249 JP-A-1-246710 JP-A-64-59704 JP-A-2-301903 JP-A-2-123616 JP-A-2-121207

  By the way, when forming a submersible motor electric wire and producing a submersible motor, it is necessary to peel off a part of protective layer, and this peeling process is a process peculiar to the electric wire used for a submersible motor. However, the conventional electric wire for underwater motors has a problem that the insulating coating layer and the protective layer are fused by heat at the time of covering the protective layer, and the protective layer is difficult to peel off from the insulating coating layer.

  Accordingly, an object of the present invention is to improve the peelability of the protective layer while maintaining the adhesiveness (water-sealing property) between the insulating coating layer and the protective layer and preventing the generation of water trees. An object of the present invention is to provide an underwater motor electric wire with improved workability and a manufacturing method thereof.

  The present invention was devised to achieve the above object, and the invention of claim 1 is an underwater motor electric wire in which a conductor shielding layer, an insulating coating layer, and a protective layer are sequentially formed on the outer periphery of a conductor. The said insulation coating layer is an electric wire for underwater motors which contains 0.5 mass part or more and 5.0 mass parts or less fatty acid amide with respect to 100 mass parts of resin of a main component.

  Invention of Claim 2 is an electric wire for submersible motors of Claim 1 whose melting | fusing point of the said fatty acid amide is 90 degreeC or more.

  Invention of Claim 3 is a manufacturing method of the electric wire for underwater motors which forms a conductor shielding layer, an insulation coating layer, and a protection layer in order on the perimeter of a conductor, and forms the insulation coating layer with resin containing fatty acid amide, In this method, the fatty acid amide is bloomed on the surface of the insulating coating layer, and the protective layer is extrusion coated.

  The invention of claim 4 melts the fatty acid amide bloomed on the surface of the insulating coating layer in the extrusion coating step of the protective layer, and melts the fatty acid amide in the cooling step after forming the protective layer. It is a manufacturing method of the electric wire for submersible motors of Claim 3 which cools and solidifies.

  The invention according to claim 5 is the fatty acid amide according to claim 3 or 4, wherein the fatty acid amide contains 0.5 to 5.0 parts by mass of fatty acid amide with respect to 100 parts by mass of the main resin. It is a manufacturing method of the electric wire for submersible motors.

  According to the present invention, the adhesiveness (water sealing property) between the insulating coating layer and the protective layer is maintained and the occurrence of water trees is prevented, the peelability of the protective layer is improved, and the workability during coil formation is improved. Can be improved.

It is sectional drawing which shows the electric wire for submersible motors which shows one embodiment of this invention. It is a figure explaining the measuring method of peeling strength in an example.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing the submersible motor electric wire according to the present embodiment.

  As shown in FIG. 1, the submersible motor electric wire 1 according to the present embodiment has a conductor shielding layer 3, an insulating coating layer 4, and a protective layer 5 sequentially formed on the outer periphery of a conductor 2 made of copper wire. is there.

  The conductor shielding layer 3 is a layer for preventing copper ions from precipitating and diffusing from the conductor 2 to the insulating coating layer 4. When copper ions are deposited and diffused from the conductor 2 to the insulating coating layer 4, a water tree due to the copper ions is generated in the insulating coating layer 4, and this water tree deteriorates the insulation performance of the coil, and finally There is a risk of causing dielectric breakdown. In order to prevent such a phenomenon, the conductor shielding layer 3 is formed between the conductor 2 and the insulating coating layer 4 in the present embodiment. The conductor shielding layer 3 is an enamel layer such as epoxy enamel, polyimide enamel, polyamideimide enamel, polyesterimide enamel, or a semiconductor in which a conductivity imparting agent such as carbon black is blended with a resin such as polyethylene or ethylene copolymer. Can be composed of layers.

  The insulating coating layer 4 is mainly composed of a polyolefin resin having excellent insulating properties and mechanical properties, and the fatty acid is 0.5 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the polyolefin resin as the main component. It contains amide. Here, polyethylene is desirable as the polyolefin-based resin, and as the polyethylene, polyethylene polymerized by an ion polymerization method, polyethylene polymerized by a radical polymerization method, or a mixture of these ion polymerization polyethylene and radical polymerization polyethylene is mixed. A polymer material mainly composed of polyethylene can be used. In addition to these polyethylenes, ethylene copolymers such as ethylene ethyl acrylate copolymer, ethylene vinyl acetate copolymer, and ethylene methacrylate copolymer, propylene and ethylene copolymer, and polyolefin contain maleic anhydride, epoxy, etc. One containing one or more of grafted functional groups may be used. Further, these polyethylenes may be crosslinked. Moreover, you may mix | blend additives, such as antioxidant and a crosslinking agent, with the said polyethylene.

  Examples of fatty acid amides include, but are not limited to, oleic acid amide, erucic acid amide, lauric acid amide, stearic acid amide, and behenic acid amide.

  Moreover, as a fatty acid amide, what has melting | fusing point is 90 degreeC or more is preferable. Examples of the fatty acid amide having a melting point of 90 ° C. or higher include stearic acid amide and behenic acid amide, but are not limited thereto. The reason why it is preferable to use a fatty acid amide having a melting point of 90 ° C. or higher is described below.

  The submersible motor wire 1 is used for a submersible motor. When the melting point of the fatty acid amide contained in the insulating coating layer 4 is less than 90 ° C., the submersible motor wire 1 is used when the submersible motor is used at a high temperature. There is a possibility that the adhesion between the insulating coating layer 4 and the protective layer 5 becomes weak, and a part of the hydrolyzed protective layer 5 peels off from the insulating coating layer 4 and diffuses into the surrounding water. Therefore, as described above, the fatty acid amide having a melting point of 90 ° C. or higher is preferably used.

  The protective layer 5 is a layer for preventing the insulating coating layer 4 from being damaged. This protective layer 5 is formed by extrusion coating. For these reasons, the protective layer 5 is made of a polyamide resin excellent in wear resistance and extrudability. Here, nylon 610, nylon 612, nylon 11, nylon 12 and the like are preferable as the polyamide resin which is the main component of the protective layer 5, but is not limited thereto.

  Since the fatty acid amide used in the present embodiment has an amide group in the molecular structure, it forms a hydrogen bond with the polyamide resin that is a constituent material of the protective layer 5, and the insulating coating layer 4 and the protective layer 5 Adhesion can be maintained.

  A method for manufacturing the submersible motor electric wire 1 will be described.

  First, the conductor shielding layer 3 is formed on the outer periphery of the conductor 2. Next, the insulating coating layer 4 is formed of a polyolefin-based resin containing the above-described amount of fatty acid amide, and the fatty acid amide is bloomed on the surface of the insulating coating layer 4.

  At this time, if the blending amount (content) of the fatty acid amide is less than 0.5 parts by mass with respect to 100 parts by mass of the resin as the main component of the insulating coating layer 4, the fatty acid amide is present on the surface of the insulating coating layer 4. It does not bloom uniformly, cannot inhibit the fusion between the insulating coating layer 4 and the protective layer 5 to be described later, does not sufficiently exhibit the effect of improving the peelability, and the amount of fatty acid amide is 5 When the insulating coating layer 4 is formed when the amount exceeds 0.0 parts by mass, the fatty acid amide is bloomed (bleeded out) in the form of powder on the surface, and the interface between the insulating coating layer 4 and the protective layer 5 after coating with the protective layer 5 As a powdery substance, the adhesion between the protective layer 5 and the insulating coating layer 4 is lowered, and the water-resistant tree characteristics of the underwater motor electric wire 1 are lowered. Therefore, in this invention, the compounding quantity of fatty acid amide is prescribed | regulated in the range of 0.5 to 5.0 mass parts with respect to 100 mass parts of polyolefin resin.

  Thereafter, the protective layer 5 is extrusion coated, so that the fatty acid amide bloomed by the heat during extrusion coating instantly melts to form a liquid layer on the surface of the insulating coating layer 4. By interposing this liquid layer between the insulating coating layer 4 and the protective layer 5, the insulating coating layer 4 and the protective layer 5 are not fused, and as a result, the peelability of the protective layer 5 at the time of coil formation is improved. Can be improved.

  In addition, the liquid layer by the fatty acid amide formed at the time of the extrusion coating of the protective layer 5 is cooled to normal temperature and solidified by a subsequent cooling step. Through the cooling process, the submersible motor electric wire 1 according to the present embodiment is obtained.

  In short, in the underwater motor electric wire 1 according to the present embodiment, the insulating coating layer 4 contains 0.5 to 5.0 parts by mass of fatty acid amide with respect to 100 parts by mass of the main resin. Therefore, the fatty acid amide bloomed on the surface of the insulating coating layer 4 during extrusion coating of the protective layer 5 forms a liquid layer, and this liquid layer is interposed between the insulating coating layer 4 and the protective layer 5.

  Therefore, the insulating coating layer 4 and the protective layer 5 are not fused by heat at the time of the extrusion coating of the protective layer 5 and can improve the excellent peelability, and the liquid layer and the protective layer 5 are bonded by hydrogen bonding. As a result, adhesion between the insulating coating layer 4 and the protective layer 5 can be maintained.

  Examples 1 to 6 and Comparative Examples 1 to 4 of the present invention will be described below.

  Table 1 shows the compositions and results of Examples 1 to 6 and Comparative Examples 1 to 4.

(Examples 1-5, Comparative Examples 1-4)
A coating mainly composed of epoxy resin was repeatedly applied to the outer periphery of a conductor made of copper wire having an outer diameter of about 4.5 mm, and baked to form a conductor shielding layer having a thickness of about 0.06 mm. On the outer periphery of the conductor shielding layer, the insulating coating layers having the respective compositions in Examples 1 to 5 to which the present invention shown in Table 1 is applied and Comparative Examples 1 to 4 which are conventional techniques are extruded with a thickness of 1.5 mm. It was coated and exposed to saturated steam at 70 ° C. for 12 hours to crosslink the insulating coating layer.

  Then, each underwater motor wire was completed by extrusion-coating a resin mainly composed of nylon 12 as a protective layer to a thickness of 0.2 mm.

(Example 6)
A semi-conductor material obtained by blending 65 parts by mass of carbon black as a conductivity imparting agent with respect to 100 parts by mass of an ethylene ethyl acrylate copolymer on the outer periphery of a conductor made of copper wire having an outer diameter of about 4.5 mm has a thickness of 0. The insulation coating layer having the composition shown in Table 1 at a thickness of 0.3 mm was simultaneously extrusion-coated at a thickness of 1.2 mm and exposed to saturated steam at 70 ° C. for 12 hours to crosslink the insulation coating layer.

  Thereafter, an underwater motor wire was completed by extrusion-coating a resin mainly composed of nylon 12 with a thickness of 0.2 mm as a protective layer.

(result)
The evaluation content shown in the lower part of Table 1 is a summary of the characteristic test results for each of the submersible motor electric wire samples according to Examples 1 to 6 and Comparative Examples 1 to 4.

  As shown in FIG. 2, the evaluation of the peelability of the protective layer is performed by cutting each completed underwater motor wire into a length of 10 cm, and cutting the protective layer 100 from its tip in the longitudinal direction of the underwater motor wire. Two pieces were put in parallel at an interval of 5 mm, and the peel strength when the protective layer 100 having a width of 5 mm was peeled from the insulating coating layer 101 was evaluated. More specifically, a part of the protective layer 100 of the submersible motor electric wire is peeled off to some extent, this is used as a sample, the end of the sample is fixed at the lower part, and the jig is attached to the load cell (load measuring instrument). The load applied to the load cell when peeling off the protective layer 100 was measured, and the maximum value of the measured value at this time was divided by the width of the protective layer 100 that was peeled off, and the peel strength was taken.

  In Table 1, if the peel strength is 1.5 N / mm or less, it is judged to be excellent, and a mark “◯” is given. Those in which the layer 100 was destroyed were judged to be defective and marked with x.

  The bleed-out of the insulating coating layer is shown in Table 1 by visually observing the produced underwater motor electric wire and judging that no powdery bloom is observed at the interface between the insulating coating layer and the protective layer. A circle was marked, and a powdery bloom was observed at the interface between the insulating coating layer and the protective layer.

  In addition, each of the submersible motor wires of Examples 1 to 6 and Comparative Examples 1 to 4 was prepared with 10 samples each of which was wound 2.5 times with the minimum bending radius (r = about 15 mm) at the time of winding formation. This was used to evaluate water tree characteristics.

  The water tree characteristics were evaluated by immersing five samples in 90 ° C. warm water and applying an AC current of 3 kV at 50 Hz between the conductor and the hot water for 500 days. After 500 days, the cross section of the insulating coating layer was thinly sliced and boiled with a methylene blue aqueous solution, the length of the water tree was measured using an optical microscope, and the number of generated water trees of 200 μm or more was counted.

If the number of occurrences is 1.0 × 10 ³ (pieces / mm ³ ) or more, it is judged as defective and an x mark is entered in Table 1, and the number of occurrences is greater than 1.0 × 10 ² (pieces / mm ³ ). If it is less than 1.0 × 10 ³ (pieces / mm ³ ), it is judged as good and a △ mark is entered in Table 1. If the generated number is 1.0 × 10 ² (pieces / mm ³ ) or less Judgment was made as excellent, and a circle in Table 1 was entered.

  The diffusion state of the hydrolyzate of the protective layer when immersed in warm water is determined in Table 1 by judging that the sample after the evaluation of the water tree characteristics is not peeled off from the insulating coating layer as the protective layer decomposed product is excellent. Enter the mark, and if the decomposition product of the protective layer is about to peel off from the insulation coating layer but has not diffused in the water, the product is judged to be good. Those that were peeled off and diffused in water were judged to be defective, and an x mark was entered in Table 1.

  As shown in the evaluation column of Table 1, Examples 1 to 6 in which fatty acid amide was blended in the insulating coating layer at a ratio of 0.5 parts by mass or more and 5.0 parts by mass or less were comparative examples in which no lubricant was blended. Compared with the comparative example 3 which mix | blended less than 0.5 mass part 1 and fatty acid amide, the peelability of a protective layer is excellent.

  Moreover, as shown in the evaluation column of Table 1, Examples 1-6 are compared with the comparative example 4 which mix | blended more than 5.0 mass parts of fatty acid amides with the insulation coating layer, and an insulation coating layer and a protective layer. There is no powdery bloom at the interface, which is good.

  Further, in Examples 1 to 6, Comparative Example 2 in which a lubricant other than fatty acid amide was blended in the insulating coating layer, Comparative Example 3 in which fatty acid amide was blended in an amount of less than 0.5 parts by mass, and Fatty Acid Amide more than 5.0 parts by mass Compared with the blended Comparative Example 4, the water tree characteristics are good.

  Moreover, Examples 1-6 are favorable compared with the comparative example 2 which mix | blended lubricants other than fatty acid amide in the insulation coating layer, and there is no spreading | diffusion to the water of the protective layer decomposition product at the time of warm water immersion, and especially melting | fusing point 90 degreeC Examples 2 to 6 blended with the above fatty acid amides are excellent with no separation of the protective layer decomposition product.

  As described above, the structure of the present invention improves the peelability of the protective layer while maintaining the adhesion (water sealing property) between the insulating coating layer and the protective layer and preventing the generation of water trees. Thus, it was proved that an electric wire for an underwater motor with improved workability at the time of coil formation can be obtained.

1 Electric wire for underwater motor 2 Conductor 3 Conductor shielding layer 4 Insulation coating layer 5 Protective layer

Claims (5)

In the electric wire for underwater motors in which the conductor shielding layer, the insulating coating layer, and the protective layer are sequentially formed on the outer periphery of the conductor,
The said insulation coating layer contains 0.5 mass part or more and 5.0 mass parts or less fatty acid amide with respect to 100 mass parts of resin of a main component, The electric wire for submersible motors characterized by the above-mentioned.   The wire for underwater motors according to claim 1 whose melting point of said fatty acid amide is 90 ° C or more. In the method of manufacturing an electric wire for an underwater motor in which a conductor shielding layer, an insulating coating layer, and a protective layer are sequentially formed on the outer periphery of the conductor,
A method for producing an electric wire for an underwater motor, wherein the insulating coating layer is formed of a resin containing a fatty acid amide, the fatty acid amide is bloomed on the surface of the insulating coating layer, and the protective layer is extrusion coated.   The fatty acid amide bloomed on the surface of the insulating coating layer is melted in the extrusion coating step of the protective layer, and the molten fatty acid amide is cooled and solidified in the cooling step after the formation of the protective layer. Item 4. A method of manufacturing an electric wire for an underwater motor according to Item 3.   The said fatty acid amide contains 0.5 mass part or more and 5.0 mass parts or less fatty acid amide with respect to 100 mass parts of resin of a main component, The manufacturing method of the electric wire for submersible motors of Claim 3 or 4 .

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