JP2008135196A - Flame-resistant polyethylene insulation wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-resistant polyethylene insulation wire excellent in flexibility, capable of making an outer diameter small without changing a cross-section area of a conductor, coating an insulator in a uniform thickness at an outermost periphery of a twisted-wire conductor, preventing an insulator from eating into an outermost periphery of the twisted-wire conductor, and easily peeling off the insulator. <P>SOLUTION: A plurality of outer-layer strands 3 are twisted together around a center conductor 2 and are compressed at high pressure to form the outer-layer strands into a fan shape at an end face having a large-diameter outside arc 3c and a small-diameter inside arc, and at the same time, an outer periphery face is smoothly formed without generating gaps between the adjacent outside arcs 3c of the plurality of outer-layer strands 3 to structure a compressed twisted-wire conductor 4, an outer periphery of which 4 is covered with an insulator 5 made of flame-resistant polyethylene resin to structure the flame-resistant polyethylene insulation wire. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flame-resistant polyethylene insulated wire, and more particularly, to a flame-resistant polyethylene insulated wire capable of easily peeling a flame-resistant polyethylene resin coated on a stranded conductor.

  In general, the insulation-coated stranded wire is formed by covering a stranded wire conductor with an insulator. When this insulation coated stranded wire is used to pass a high-frequency current through the conductor of the coated wire, the current flows more as the high-frequency current is closer to the outer periphery of the conductor cross section, and conversely, the current is less likely to flow as it is closer to the center of the conductor cross section. A phenomenon called effect occurs. In order to reduce the skin effect, a conventional insulated coated stranded wire conductor coated with an insulator is provided with a single central conductor and a plurality of strands arranged around the central conductor. A conductor is used (for example, refer to Patent Document 1). This concentric stranded annealed copper conductor has six, twelve, twenty-four strands having the same outer diameter as that of the central conductor arranged around one central conductor. 4 has a structure in which six strands are twisted and arranged.

  In such an insulation coated stranded wire conductor 51, a plurality of strands 55 constituting the outer layer 54 are arranged around the strand 53 constituting the inner layer 52 and twisted to form a stranded wire conductor 58. An insulator 56 made of resin is formed on the outer periphery. In the conventional insulated coated stranded wire conductor 51, the wire 53 of the inner layer 52 and the wire 55 of the outer layer 54 have the same diameter.

  Since the concentric stranded annealed copper conductor used for such an insulation-coated stranded wire conductor 51 is often used in the wiring of automobiles, the inside of electronic devices, etc., it has been required to reduce the outer diameter. In the concentric stranded annealed copper conductor, one central conductor and the strands arranged around the central conductor are formed in a circular shape having the same outer diameter. It was a big one.

  However, since the insulation-coated stranded conductor 51 of Patent Document 1 is formed in a circular shape in which one central conductor and the strands arranged around the central conductor have the same outer diameter, The outer diameter of the annealed copper conductor is large, and it does not meet the demand for reducing the diameter of electric wires used in low voltage wiring of automobiles and the like. In view of this, at least six peripheral strands are arranged adjacent to each other around a single central strand so as to surround the central strand, and the diameter of the central strand is defined as the peripheral strand. There has been proposed a structure in which an insulation-coated stranded wire conductor is formed using a compressed conductor obtained by compressing a peripheral strand toward the center of its aggregate form using a wire having a diameter smaller than the diameter of the wire (for example, Patent Documents) 2).

  As shown in FIG. 2, in the compressed conductor 2 of Patent Document 2, first, six peripheral strands 3b are adjacent to each other around a single central strand 3a along the circumferential direction. Collectively arranged in a state and twisted around the center strand 3a. In this state, the central axes of the peripheral strands 3b are respectively arranged at the positions of the regular hexagonal item points centered on the central strand 3a. Then, the aggregate form of the central strand 3a and the six peripheral strands 3b is compressed toward the center of the aggregate form (center of the central strand 3a).

Then, the peripheral strands 3b are deformed and moved toward the center of the aggregated form while being deformed under the influence of each other by being pressed at the contact portions. At this time, a slight play is provided between the central strand 3a and each peripheral strand 3b. For this reason, the center strand 3a is not in close contact with each peripheral strand 3b or is in close contact with a weak force, and the compressed conductor 2 as shown in FIG. 1 is formed.
JP 2003-51214 A (2nd page, FIG. 4) Japanese Patent Laid-Open No. 2002-100214 (2nd page, FIG. 1)

  As described above, the flame-resistant polyethylene insulated wire 51 of Patent Document 1 is a stranded wire constituted by arranging and twisting a plurality of strands 55 constituting the outer layer 54 around the central conductor (the strand 53 of the inner layer 52). The conductor 58 is configured by coating a flame resistant polyethylene resin as the insulator 56. Since the stranded wire conductor (twisted conductor) 58 used in the flame resistant polyethylene insulated wire 51 of Patent Document 1 is formed in a circular shape with all the strands 53 and 54 constituting the stranded wire conductor 58, When twisted together, large irregularities are formed on the outermost periphery of the conductor. In this state, when the stranded wire conductor (twisted conductor) 58 is coated with the flame-resistant polyethylene resin as the insulator 56, the insulation is coated on the outermost periphery of the conductor, that is, the concave portion of the large unevenness formed on the outer periphery of the outer layer 54. The coating material (flame-resistant polyethylene resin) which is the body 56 will bite in.

Also, in the case of the electric wire 1 using the compressed conductor 2 of Patent Document 2, as shown in FIG. 1, the peripheral strands 3b are pressed by mutual contact portions and deformed under the influence of each other, Deformation moves toward the center of the collective form. However, there is some play between the central strand 3a and each peripheral strand 3b, and the central strand 3a does not adhere to each peripheral strand 3b or with a weak force. As shown in FIG. 1, the compressed conductor 2 of Patent Document 2 is in close contact with each other when the central strand 3 a and the six peripheral strands 3 b constituting the compressed conductor 2 are twisted together. Unevenness is formed on the outermost periphery of the compressed conductor 2.
In this state, when an insulating stomached portion (flame-resistant polyethylene resin) 5 is coated on the compressed conductor 2, an insulated stomached portion (flame-resistant polyethylene) coated on a concave portion having large irregularities formed on the outermost periphery of the compressed conductor 2. Resin) 5 bites in.

  In the flame-resistant polyethylene insulated wire of Patent Document 1, when the end of the flame-resistant polyethylene insulated wire is processed, the insulator 56 is peeled off and the stranded conductor (twisted conductor) 58 is exposed. When the insulator 56 is peeled off from the stranded wire conductor (twisted conductor) 58, a coating material (flame resistance) which is the insulator 56 coated on the concave portion of the outermost outer periphery of the stranded wire conductor (twisted conductor) 58. (Polyethylene resin) is biting in, so that the peelability of the coating material (flame-resistant polyethylene resin) is extremely poor.

  Moreover, when processing the terminal of the electric wire 1 flame-resistant polyethylene insulation electric wire using the compression conductor 2 of patent document 2, peeling the insulation stomach part (flame-resistant polyethylene resin) 5 and exposing the compression conductor 2 is performed. . When peeling the insulated stomach part (flame resistant polyethylene resin) 5 from the compressed conductor 2, a coating material (insulating stomach part (flame resistant polyethylene resin) 5) coated on the concave portion of the large unevenness on the outermost periphery of the compressed conductor 2 ( Since the (flame-resistant polyethylene resin) bites in, the peelability of the coating material (flame-resistant polyethylene resin) is extremely poor.

  In the case of a vinyl chloride insulated wire, the coating material is made of vinyl chloride resin. Due to the properties of this vinyl chloride resin material, the coating material (chlorine chloride) is formed on the concave portion of the outermost periphery of the stranded wire conductor (twisted conductor) 58. Even if a (vinyl resin) bites in, it can be easily peeled off. However, in the case of a flame-resistant polyethylene insulated wire using a flame-resistant polyethylene resin as a coating material, the flame-resistant polyethylene resin has a property of being in close contact with the conductor, and a stranded conductor (twisted conductor) 58, a compressed conductor 2 If the coating material (polyethylene resin) bites into the concave portion of the large unevenness on the outermost periphery of the outer periphery, the coating layer thickness of the flame-resistant polyethylene resin is not uniform as the coating material, and it becomes very difficult to peel off have.

  The purpose of the present invention is excellent in flexibility, can reduce the outer diameter without changing the cross-sectional area of the conductor, can coat the outermost periphery of the stranded conductor with a uniform thickness, An object of the present invention is to provide a flame-resistant polyethylene insulated wire that prevents an insulator from biting into the outermost periphery of a stranded wire conductor and can easily peel the insulator.

  In order to solve the above-described problem, the flame-resistant polyethylene insulated wire according to claim 1 is formed by twisting a plurality of outer layer strands around the outer periphery of the central conductor and compressing the outer layer strands at a high pressure, A twisted conductor is formed by forming an end surface fan having a small-diameter inner arc, and smoothly forming an outer peripheral surface without causing a gap between outer arcs of the plurality of outer layer strands, The outer periphery of the conductor is configured by covering an insulator layer made of a flame resistant polyethylene resin.

  According to the invention of claim 1 having such characteristics, the outermost peripheral surface of the multi-core conductor obtained by twisting strands is strongly compressed, and the surface of the twisted conductor (twisted conductor) is close to a perfect circle. Molded into a shape, the unevenness on the outermost periphery of the twisted conductor (stranded conductor) is removed, and the gap between the outer peripheral strands is eliminated, preventing biting between the conductor strands of the flame resistant polyethylene insulator be able to.

  In order to solve the above-mentioned problem, the flame-resistant polyethylene insulated wire according to claim 2 is the flame-resistant polyethylene insulated wire according to claim 1, wherein each outer layer strand twisted around the outer periphery of the center conductor is connected to the center conductor. The diameter is smaller than the diameter.

  According to invention of Claim 2 which has such a characteristic, it twists together the strand which comprises a twisted conductor (stranded conductor) using a strand with a larger outer diameter than a conventional product, Since a wire thicker than other wires is used, the conductor cross-sectional area after strong compression can be made equal to that of the conventional product, and a conductor resistance value which is one of the electric wire required characteristics can be satisfied.

  According to the flame-resistant polyethylene insulated wire of the present invention, the outer diameter can be reduced without changing the cross-sectional area of the conductor with excellent flexibility, and the insulation is made to have a uniform thickness on the outermost periphery of the stranded wire conductor. It can coat | cover, it can prevent that an insulator bites into the outermost periphery of a strand wire conductor, and can peel an insulator easily.

  Hereinafter, description will be given with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the flame-resistant polyethylene insulated wire of the present invention.

  In FIG. 1, 1 is a flame resistant polyethylene insulated wire according to the present invention. This flame-resistant polyethylene insulated wire 1 has a structure having a central conductor 2 and a fan-shaped outer layer strand 3, and a plurality of outer layer strands 3 are twisted around the outer periphery of one center conductor 2. Compressed twisted wire conductor 4 is formed by compression. The compression stranded conductor 4 is formed by arranging and arranging six outer layer strands 3 adjacent to each other so as to surround the central conductor 2 along the circumferential direction, and twisting them together to form a stranded conductor. Further, the stranded wire conductor 4 is formed by strongly compressing the stranded wire conductor.

  As described above, the six outer layer conductors 3 are provided on the outer periphery of the center conductor 2. Each of the six outer layer conductors 3 is obtained by drawing one element wire so as to have a fan shape. The six outer layer strands 3 are arranged along the outer periphery of the center conductor 2. In the present embodiment, six outer layer conductors 3 having the same shape are arranged on the outer periphery of the center conductor 2. That is, in the present embodiment, the adjacent side surfaces of the six outer layer strands 3 are in surface contact with each other, and the six outer layer strands 3 are integrated to form an end surface in a substantially ring shape.

In the present embodiment, the center conductor 2 is made of soft copper or the like as in the case of the conventional center conductor, and the size of the outer diameter is the same as the conventional size.
The center conductor 2 is formed in a perfect circle. By forming the central conductor 2 into a perfect circle, when the electric wire is formed by extruding a resin concentrically on the central conductor 2, the electric wire can obtain good flexibility. ing.
A plurality of outer layer wires 3 are twisted around the outer periphery of the center conductor 2 formed into a perfect circle. In the present embodiment, six outer layer strands 3 are twisted into one central conductor 2. In the drawing, this outer layer strand 3 is a strand formed so that its end face has a fan shape, and is twisted around the outer periphery of the center conductor 2 along the longitudinal direction of the center conductor 2.

  In the present embodiment, the diameter of the plurality of outer layer strands 3 twisted around the outer periphery of the center conductor 2 is configured to be smaller than the diameter of the center conductor 2. That is, the central conductor 2 strands and the six outer layer strands 3 constituting the compression stranded wire conductor 4 are twisted together with a thicker outer diameter than the conventional product, and the center strand 2 is the other six outer layer strands. A thing thicker than the line 3 is used. If the outer layer strand 3 having the same outer diameter as that of the conventional product is strongly compressed, the conductor cross-sectional area becomes extremely small and it becomes difficult to satisfy the conductor resistance value, which is one of the required electric wire characteristics. The cross-sectional area is the same as the conventional product.

  Six outer layer strands 3 are gathered and arranged adjacent to each other so as to surround the central conductor 2 along the circumferential direction, and these are twisted together to form a stranded wire conductor. Each of the six outer layer strands 3 of the compression stranded conductor 4 formed by strongly compressing the conductor has a structure having side surfaces 3a and 3b at both ends as shown in FIG. When 3 is joined to the central conductor 2, the side surface 3a and the side surface 3b of the adjacent outer layer strand 3 are in surface contact with each other. Further, each outer arc 3c of the six outer layer strands 3 strongly compresses the outermost peripheral surface of the stranded wire conductor formed by twisting the six outer layer strands 3 to form a compressed stranded conductor 4 And the surface of the compressed stranded conductor 4 is formed in a shape close to a perfect circle. And it joins so that a clearance gap may not arise in the boundary (between each outer periphery strand 3) of the side surface 3a and side surface 3b of each adjacent outer layer strand 3 of the six outer layer strands 3, Unevenness generated on the outermost periphery is removed, and the conductor surface of the compressed stranded wire conductor 4 is formed on a smooth surface.

  The compression stranded wire conductor 4 is manufactured by strongly compressing a twisted conductor by a compressor 10 as shown in FIG. That is, the center conductor 2 and the six outer layer strands 3 are separated from the compressor 10 so as to be collectively arranged adjacently so as to surround the center conductor 2 along the circumferential direction. It is sent out through the board 11. The state where the center conductor 2 and the six outer layer strands 3 that have come out of the dividing board 11 are adjacent to each other so as to surround the center conductor 2 along the circumferential direction by the twisting cap 12 of the compressor 10. To form a circular twisted conductor (stranded conductor) 13.

  The circular twisted conductor (twisted wire conductor) 13 twisted in this manner is compressed in the first-stage compression die 14. The circular stranded conductor (stranded conductor) 13 compressed by the compression die 14 becomes a primary compression stranded wire 15. The primary compression stranded wire 15 is a normal compression conductor, but the groove 15a between the outer strands 3 is smaller than the groove 13a of the circular stranded conductor (stranded wire conductor) 13, but the groove 5a is , Completely left.

Next, the primary compression stranded wire 15 formed by being compressed in the first-stage compression die 14 is sent to the next-stage compression die 16, and is strongly compressed by the compression die 16, and the compression strand conductor 17 It becomes. The compression die 16 is not limited to a single stage, and has a plurality of stages of compression dies having different inner diameters. Although this compression die 16 is represented by one for convenience, the groove 15a between each outer layer strand 3 of the primary compression stranded wire 15 is eliminated, and the outermost layer surface of the primary compression stranded wire 15 becomes smooth, and the compression stranded wire. It has the number of steps until the conductor 17 is molded. The number of compression dies through which the primary compression stranded wire 15 constituting the compression dies 16 passes is:
(1) Number of outer layer strands 3 to be twisted (2) Outer diameter of strands (3) Depends on outer diameter after twisting.

This is because, when the primary compression stranded wire 15 is rapidly compressed, a residual stress is strongly generated in the outer layer strand 3. When residual stress is strongly generated inside the outer layer strand 3, the outer layer strand 3 is broken (disconnected). For this reason, depending on said conditions, it must compress gradually through 3-5 compression dies.
Further, in this method, the conductor after twisting becomes remarkably hard due to the work hardening of the metal, and the bending and stretching performance required as a conductor for electric wires and cables is greatly lost. For this reason, the compression twisted wire conductor 17 that has passed through the final compression die 16 of the compression die 16 and the outermost layer surface of the primary compression twisted wire 15 is smooth and strongly compressed is passed through the continuous annealing machine 20 and compressed by work hardening. The stranded wire conductor 17 is continuously annealed and softened.

A flame resistant polyethylene resin is coated as an insulator 5 on the compression stranded conductor 4 formed in this way. As described above, the flame-resistant polyethylene resin is used as the insulator 5 in the case of a conventional insulated wire using a polyvinyl chloride resin composition for the insulator 5, for example, burning the wire for incineration disposal Then, there was a problem that corrosive hydrogen chloride gas was generated from the polyvinyl chloride resin composition.
Therefore, in recent years, attempts have been made to use an olefin resin composition (for example, polyethylene) as an insulator and use an insulated wire that does not use a halide as an insulated wire at a location that generates a high temperature, such as an automobile wire harness. In the case of this olefin-based resin composition (for example, polyethylene), since it is not flame retardant by itself, in the flame-resistant polyethylene insulated wire, a metal hydroxide such as magnesium hydroxide is mixed with the polyethylene resin as the insulator 5. It has flame resistance.

Examples of the olefin resin include polypropylene, polyethylene, ethylene vinyl acetate copolymer, and ethylene ethyl acrylate copolymer, and any one of these or a mixture of two or more thereof can be used.
Other olefin resins that can be used in the non-halogen flame retardant polyolefin composition include linear low density polyethylene, low density polyethylene, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-methacrylate. Examples include acid copolymers, high density polyethylene, polypropylene, metallocene linear low density polyethylene, metallocene ultra low density polyethylene, and ethylene-propylene copolymers.
In the present embodiment, polyethylene among olefin-based resins is used.

  The metal hydroxide to be blended with polyethylene as the insulator 5 is composed of one or a mixture of two or more of magnesium hydroxide, aluminum hydroxide, zirconium hydroxide, calcium hydroxide and barium hydroxide. Can do. When this metal hydroxide (for example, magnesium hydroxide) is blended with an olefin resin (for example, polyethylene) to burn the olefin resin (for example, polyethylene) composition, the blended metal hydrate ( For example, the water of crystallization contained in magnesium hydroxide) fires and fire extinguishes, making it difficult for olefin-based resins (for example, polyethylene) to combust. have.

Also, standards for insulated wires using olefin-based resin compositions (for example, polyethylene) have been established both in Japan and abroad, and recently, insulated wires that meet foreign standards have been required. In foreign standards, there is an ICEA standard as a vertical test. This ICEA-standard single-wire single-wire vertical combustion test (ICEA S61-402 (NEMA WCS) vertical combustion test) is performed as follows.
First, fix a sample wire with a length of about 560 mm on the top of a metal box and hang it. A tyryl burner with a 9.5 mm diameter, 102 mm long spark plug from the air inlet to the tip. Set on an inclined table of 20 °, use city gas, adjust the length of the burner flame to 127 mm, adjust the length of the blue flame inside to 38.1 mm, and place it at the tip of the burner blue flame. Adjust to hit the sample. A kraft paper having a thickness of 0.127 mm and a width of 12.7 mm is wound once on the upper part of the sample, and the indicator is set with a length of 19.0 mm. After setting in this manner, the burner spark plug was lit, the burner valve was opened, the sample was applied to the sample for 15 seconds, and then the valve was closed and rested for 15 seconds, and the operation was repeated four times. After 5 times of flames on the sample, the case where 25% of the kraft paper burns is determined to be fire spreadability, and if the sample continues to burn for more than 1 minute, it is rejected.

For the polyethylene used as the insulator 5, a cross-linked cross-linked polyethylene may be used.
In the crosslinking method, γ rays or electron beams are used as a radiation source, and when these are irradiated onto polyethylene, radicals are generated in the molecules, and these radicals couple with each other to form molecular bonds. Radiation-induced cross-linking, organic peroxide that does not decompose at the plasticizing temperature of polyethylene is blended, and when exposed to high temperature and high pressure at the same time as or after molding, the organic peroxide decomposes and radicals are generated. Crosslinking reaction between molecules is promoted by radicals. After graft addition reaction of vinyl silane compound to polyethylene, silanol condensation catalyst is added to this graft polymer, and after molding, it is exposed to moisture atmosphere. After hydrolysis of the alkoxysilanes, the dehydrated silane bridge forms a cross-linking bond between the molecules. (Water crosslinking) There are, it may be in this one way.

In this way, the compression stranded conductor 4 coated with the flame-resistant polyethylene resin as the insulator 5 is twisted by twisting the central conductor 2 strand and the six outer layer strands 3 with a larger outer diameter than the conventional product. The wire 2 is thicker than the other six outer layer wires 3, and the outer layer wire 3 having the same outer diameter as that of the conventional product is strongly compressed so that the cross-sectional area of the conductor after the strong compression is equal to that of the conventional product. The surface of the compression twisted wire conductor 4 is formed in a shape close to a perfect circle. Moreover, there is no gap at the boundary between the side surface 3a and the side surface 3b of each of the adjacent outer layer strands 3 of the six outer layer strands 3 constituting the compression stranded wire conductor 4 (between the outer peripheral strands 3). Thus, the unevenness generated on the outermost periphery of the compressed stranded wire conductor 4 is removed, and the conductor surface of the compressed stranded wire conductor 4 is formed on a smooth surface.
For this reason, when a flame resistant polyethylene resin is coated on the compression stranded wire conductor 4 as the insulator 5, the coated flame resistant polyethylene resin is used to remove the outermost irregularities of the compression stranded wire conductor 4 and between the outer strands 3. By eliminating this gap, biting between the conductor wires is prevented.

Therefore, according to the present embodiment, it is possible to prevent biting of the flame-resistant polyethylene resin as the insulator material between the outer strands 3 and improve the peelability of the insulator 5 from the compressed stranded wire conductor 4. .
In addition, according to the present embodiment, even if the conductor surface is strongly compressed and a smooth conductor surface is formed, it is possible to ensure electrical requirements.

It is sectional drawing which shows one Embodiment of the flame-resistant polyethylene insulated wire of this invention. FIG. 2 is a partially enlarged cross-sectional view of a compression stranded conductor of the flame resistant polyethylene insulated wire illustrated in FIG. 1. It is a schematic diagram for demonstrating the process of the compressor which manufactures the compression strand wire conductor shown in FIG.

Explanation of symbols

1 …………………… Flame resistant polyethylene insulated wire 2 …………………… Center conductor 3 …………………… Outer layer wire 3c …………………… Outer arc 4 …… ……………… Compressed twisted conductor 5 …………………… Insulator 10 …………………… Compressor 11 ………………… Splitting board 12 ………………… Twisted cap 13 …………………… Conductor (stranded conductor)
14 ……………… Compression die 15 …………………… Primary compression stranded wire 16 ……………… Compression die 17 …………………… Compression stranded wire conductor 20 ……………… ...... Continuous annealing machine

Claims (2)

A plurality of outer layer strands are twisted around the outer periphery of the central conductor and compressed at a high pressure, and the outer layer strands are formed in an end face fan shape having a large-diameter outer arc and a small-diameter inner arc,
And forming a compressed stranded conductor by smoothly forming the outer peripheral surface without causing a gap between the outer arcs of the plurality of adjacent outer layer strands,
A flame-resistant polyethylene insulated wire obtained by coating an outer periphery of the compressed stranded wire conductor with an insulator layer made of a flame-resistant polyethylene resin. Each outer layer strand twisted around the outer periphery of the center conductor is
The flame resistant polyethylene insulated electric wire according to claim 1, wherein the electric wire is composed of a diameter smaller than the diameter of the central conductor.

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