CN106560899A - Insulating electric wire - Google Patents

Abstract

The present invention provides an insulated electric wire provided with flame retardancy, in which defects caused by reduction in elongation and tensile strength are improved. The insulated wire has at least a center conductor (11) and an insulator (12) covering the periphery of the center conductor (11). The insulator (12) is formed by adding a halogen-containing flame retardant and silica to a polyolefin resin and cross-linking it. The average particle diameter of silica is 0.1-1.0 micrometers, and 10-15 weight part of silica is added with respect to 100 weight part of polyolefin resins.

Description

insulated wire

technical field

The present invention relates to an insulated electric wire, and more specifically, to an insulated electric wire in which flame retardancy is imparted to an insulator covering around a conductor.

Background technique

Insulated wires used in internal wiring of electronic equipment and wiring for automobiles are required to be flame retardant. Insulated wires used in electrical equipment or electronic equipment, or insulated wires that are subject to the upper limit control of the operating temperature of insulators in the Electrical Appliances and Materials Safety Act, require a predetermined level of flame retardancy characteristics.

As a flame retardant material for improving the flame retardancy of an insulated wire, an inorganic filler such as silica may be blended into a resin compound such as a polyolefin resin. For example, Patent Document 1 discloses an insulated wire using a resin composition in which an inorganic filler and an organosilicon compound are mixed with a polymer material. Here, it is described that metal oxides such as silica are used as the inorganic filler. The particle size of the inorganic filler is preferably set within a range of 0.1 to 10 μm, and the compounding amount thereof is preferably set to 50 to 250 parts by weight relative to 100 parts by weight of the polymer material. When molding an insulated wire, the composition containing the above-mentioned inorganic filler and organosilicon compound is extruded and coated on the core conductor, and ionizing radiation such as electron beams is irradiated, thereby making the polymer material of the composition crosslinking.

prior art literature

patent documents

Patent Document 1: Japanese Patent Application Laid-Open No. 6-256567

Contents of the invention

The problem to be solved by the invention

According to the compounding described in Patent Document 1, compared to an insulated wire obtained by adding an inorganic filler to a polymer material, extrusion coating molding, and crosslinking, the elongation (Elongation) and the resistance at break In terms of tensile strength (Tensile Strength), insulated electric wires having insulators with good properties are further required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an insulated electric wire provided with flame retardancy in which elongation and tensile strength are improved.

Solution to the problem

The insulated wire of the present invention is an insulated wire having at least a conductor and an insulator covering the periphery of the conductor, wherein the insulator is made by adding a halogen-containing flame retardant and silicon dioxide to a polyolefin-based resin and cross-linked. The silica has an average particle diameter of 0.1 to 1.0 μm, and 10 to 15 parts by weight of silica is added relative to 100 parts by weight of the polyolefin resin.

Invention effect

According to the present invention, it is possible to provide an insulated electric wire imparted with flame retardancy in which elongation and tensile strength are improved.

Description of drawings

1A is a diagram showing a configuration example of an insulated wire according to the present invention, and is a diagram showing a configuration of an insulated wire in which the periphery of a central conductor is covered with an insulator.

1B is a diagram showing a configuration example of an insulated wire according to the present invention, and is a diagram showing a configuration of a coaxial wire in which the periphery of a central conductor is covered with an insulator, an outer conductor is further provided, and the outside of the outer conductor is covered with an outer coating.

Fig. 2 is a graph showing measurement results of elongation and tensile strength in Examples and Comparative Examples of the present invention.

Symbol Description

10...Insulated wire, 11...Central conductor, 12...Insulator, 13...Outer conductor, 14...Sheath.

detailed description

First, embodiments of the present invention will be described.

(1) The insulated wire of the present application is an insulated wire having at least a conductor and an insulator covering the periphery of the conductor, wherein the insulator is obtained by adding a halogen-containing flame retardant and silicon dioxide to a polyolefin-based resin and It is formed by cross-linking, the particle size of the silica is 0.1-1.0 μm, and 10-15 parts by weight of silica is added to 100 parts by weight of the polyolefin resin. Accordingly, it is possible to provide an insulated electric wire provided with flame retardancy, in which defects caused by reduction in elongation and tensile strength are improved.

(2) The polyolefin-based resin is preferably obtained by mixing ethylene-vinyl acetate copolymer resin and polyethylene resin. Thus, a polyolefin-based resin material suitable for flame-retardant insulated wires is provided.

(3) The weight mixing ratio of the ethylene-vinyl acetate copolymer resin and polyethylene resin is preferably in the range of 2:8˜5:5. Thereby, the most suitable mixing ratio of the ethylene-vinyl acetate copolymer resin and the polyethylene resin for improving the defects caused by the reduction of the elongation and the tensile strength is provided.

[Details of Embodiments of the Present Invention]

Specific examples of the insulated wire of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, It is shown by the scope of a claim, and all the changes within the scope of a claim and the equivalent range are included.

1A and 1B are diagrams showing configuration examples of the insulated wire of the present invention. The insulated wire 10 shown in FIG. 1A has a structure in which the periphery of the center conductor 11 is covered with an insulator 12 .

In addition, the insulated electric wire 10 shown in FIG. 1B is configured as a coaxial electric wire in which the periphery of the center conductor 11 is covered with an insulator 12, and an outer conductor 13 is provided on the outer periphery of the insulator 12, and an outer jacket (also called a sheath) 14 is used. The outside of the outer conductor 13 is covered for protection. Embodiments of the present invention are applicable to any of the configurations shown in FIGS. 1A and 1B .

The insulator 12 of FIG. 1A and FIG. 1B is characteristic of the embodiment of the present invention, and is formed by adding a halogen-containing flame retardant and silica to a polyolefin resin and cross-linking. The particle size of the silica is 0.1- 1.0 μm, 10 to 15 parts by weight of silica is added with respect to 100 parts by weight of the polyolefin-based resin. In addition, in the structure of the insulated electric wire 10 of FIG. 1A, the structure which coat|covers the periphery of the center conductor 11 with the resin material of multiple layers may be used. In this case, the innermost resin material layer covering the periphery of the center conductor 11 is set to be the above-mentioned polyolefin-based resin layer blended with a halogen-based flame retardant and silica.

In the configuration of Fig. 1A and Fig. 1B, the center conductor 11 is formed by a single wire or a twisted wire of a plurality of plain wires, and can be made of (for example) copper, mild steel, silver, nickel-plated mild steel, tin-plated mild steel, etc. Conductors made of conductive materials such as steel and silver-plated mild steel wire. The central conductor 11 preferably has a cross-sectional area of 2 to 40 mm ² .

The insulator 12 is obtained by adding a halogen-containing flame retardant and silica to polyolefin-based resin, and cross-linking with electron beams or the like.

As the polyolefin-based resin used as the base of the insulator 12, ethylene-vinyl acetate copolymer or polyethylene can be used, and a mixture of ethylene-vinyl acetate copolymer and polyethylene can be used particularly preferably. In this case, the weight mixing ratio of the ethylene-vinyl acetate copolymer and polyethylene is preferably in the range of 2:8 to 5:5. That is, in a two-component mixing system of an ethylene-vinyl acetate copolymer and polyethylene, the weight mixing ratio of the ethylene-vinyl acetate copolymer is preferably within a range of 20% to 50%.

As polyethylene, low-density polyethylene (LDPE), linear low-density polyethylene (L-LDPE), and high-density polyethylene (HDPE) can be used. As other polyolefin-based resins, ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA) and the like can be used.

The halogen-containing flame retardant imparts flame retardancy to the insulated wire 10, and an organic flame retardant containing a halogen atom can be used. For example, brominated aromatic compounds can be used as halogenated organic flame retardants. As the brominated aromatic compound, for example, polybrominated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE) can be used. In this embodiment, no flame retardants based on metal hydroxides, metal oxides, metal carbonates, etc. are added, but these flame retardants can be used as needed.

Silica is blended as an inorganic filler that imparts flame retardancy to the insulated wire 10 . In addition, by blending silica, the tensile strength of the insulator 12 can be increased.

The particle size of the silica is preferably in the range of 0.1 to 1.0 μm, and it is preferably blended in 10 to 15 parts by weight with respect to 100 parts by weight of the polyolefin-based resin serving as the base of the insulator 12 . When the particle size of the silica is larger than the above range, the dispersibility of the silica in the polyolefin-based resin deteriorates, and the elongation and tensile strength of the polyolefin-based resin decrease. In particular, when a mixture of ethylene-vinyl acetate copolymer and polyethylene is used, the dispersibility of silica with a large particle size in polyethylene is poor, and the elongation and tensile strength are reduced. By optimizing the particle size of the silica to be in the range of 0.1 to 1.0 μm, the dispersion of the silica in the polyolefin resin can be improved, and the decrease in elongation and tensile strength of the polyolefin resin can be prevented.

Other compounding components such as a lubricant, an anti-aging agent, a processing aid, and a coloring agent may be appropriately compounded in the polyolefin-based resin serving as the base of the insulator 12 as required.

In the case of the coaxial wire shown in FIG. 1B , the outer conductor 13 is formed by winding, for example, an annealed copper wire or a copper alloy wire, or a silver-plated or tin-plated annealed copper wire on the outer periphery of the insulator 12 by braiding or horizontal winding. . Alternatively, a metal tape is wound as the outer conductor 13 . The cover 14 may be made of the same material as the insulator 12 . Alternatively, the outer sheath 14 may be appropriately formed by extrusion molding PVC (vinyl chloride resin), polyethylene resin, fluororesin material, or the like, or by winding a resin tape such as a polyester tape.

In the insulated wire 10 having the above configuration, the insulator 12 is cross-linked to give a three-dimensional network structure. Here, the center conductor 11 is extrusion-coated with polyolefin-based resin containing a halogen-based flame retardant and a compounding agent such as silica as described above, and electron beams are irradiated to the extrusion-coated polyolefin-based resin. , and thus the polyolefin-based resin can be crosslinked.

By irradiating electron beams as described above, polyolefin-based resins can be effectively cross-linked in terms of cross-linking speed and simplicity. In addition, other ionizing radiation such as α-rays, γ-rays, X-rays, and ultraviolet rays can be irradiated. The polyolefin-based resin is cross-linked, or a method of kneading an organic peroxide in a polyolefin-based resin beforehand and heating to cross-link, or a method such as water cross-linking can be used.

By combining the above configurations, there is provided an insulated wire having at least a conductor and an insulator covering the periphery of the conductor, wherein the insulator is obtained by adding a halogen-containing flame retardant and silicon dioxide to a polyolefin-based resin and In the cross-linked form, 10 to 15 parts by weight of silica having a particle diameter of 0.1 to 1.0 μm is added to 100 parts by weight of the polyolefin-based resin. The polyolefin resin is obtained by mixing ethylene-vinyl acetate copolymer resin and polyethylene resin, and their weight mixing ratio is preferably in the range of 2:8 to 5:5. By adding silica, it is possible to increase the tensile strength of the polyolefin resin while imparting flame retardancy to the polyolefin resin. At this time, by setting the particle size of the silica in the range of 0.1 to 1.0 μm, the dispersibility of the silica to the polyolefin resin can be improved, and the elongation of the polyolefin resin due to poor dispersion of the silica can be prevented. reduction in rate and tensile strength. Accordingly, it is possible to provide an insulated electric wire provided with flame retardancy, in which defects caused by reduction in elongation and tensile strength are improved.

(Example)

In the structure of FIG. 1A, polyolefin-based resin is coated and molded around the center conductor 11, cross-linked by electron beams to form an insulated wire 10, and the elongation of the polyolefin-based resin (elongation at break ( %); Elongation) and tensile strength (tensile strength at break; Tensile Strength). The results of the measurement are shown in FIG. 2 .

As the central conductor 11, made of twisted 41 outer diameter The stranded wire made of tinned annealed copper wire is set to have a cross-sectional area of 2 mm ² . As the polyolefin-based resin to coat around the center conductor 11 , a resin obtained by mixing ethylene-vinyl acetate copolymer (EVA) and polyethylene (PE) at the weight ratio shown in FIG. 2 is used. A halogen-containing flame retardant and silica are blended into a polyolefin resin. The average particle diameter (D50) of silica and the compounding quantity (parts by weight) to polyolefin resin (mixture of EVA and PE) were changed. Then, the polyolefin-based resin compounded with a halogen-containing flame retardant and silica is extruded around the central conductor 11 to perform coating molding, and then irradiated with electron beams to cross-link the polyolefin-based resin to obtain an insulated wire. . The thickness of the coating layer made of polyolefin resin was 0.76 mm, and the outer shape of the insulated wire was 3.59 mm. The elongation and tensile strength of the polyolefin resin of the insulated wire were measured. As a measurement method, after the crosslinking of the polyolefin resin, a sample with a width of 10 mm is taken from the coating layer formed of the polyolefin resin, and the elongation at break and the strength at break of the sample are measured with a tensile tester. (tensile strength).

No. 1 to No. 3 shown in FIG. 2 are examples, and No. 4 is a comparative example. In this configuration, the elongation is required to be 400% or more and the tensile strength is 14.7 MPa (1.50 kg/mm ² ). As far as the example of No.1 is concerned, the weight mixing ratio of EVA and PE is 4:6, the average particle size of silica is 0.1 μm, and the compounding amount of silica relative to the mixture of EVA and PE is 15 parts by weight . The elongation at this time was 425%, the tensile strength was 16.9 MP, and both the elongation and the tensile strength were at a good level.

As far as the No.2 example is concerned, the weight mixing ratio of EVA and PE is 5:5, the average particle size of silica is 1.0 μm, and the compounding amount of silica relative to the mixture of EVA and PE is 10 parts by weight . The elongation at this time was 447%, the tensile strength was 15.5 MP, and both the elongation and the tensile strength were at a good level.

As far as the example of No.3 is concerned, the weight mixing ratio of EVA and PE is 2:8, the average particle size of silicon dioxide is 0.1 μm, and the compounding amount of silicon dioxide relative to the mixture of EVA and PE is 15 parts by weight . The elongation at this time was 409%, the tensile strength was 17.7 MP, and both the elongation and the tensile strength were at a good level.

On the other hand, in Comparative Example No. 4, the weight mixing ratio of EVA and PE was 4:6, the average particle diameter of silica was 6.0 μm, and the blending amount of silica to EVA/PP was 10. parts by weight. The elongation at this time was 379%, and the tensile strength was 14.5 MPa, and both the elongation and the tensile strength were unfavorable levels. Therefore, by setting the average particle diameter of silica to 0.1 to 6.0 μm and the weight ratio of EVA to PE in the range of 2:8 to 5:5, the compounding amount of silica to EVA/PE is set to 10-15 parts by weight, an insulated wire with good elongation and tensile strength can be obtained.

Claims (3)

1. a kind of insulated electric conductor, its at least there is conductor and the coating conductor around insulator, wherein,

The insulator is to add the fire retardant containing halogen and silicon dioxide relative to polyolefin-based resins and be crosslinked,

The mean diameter of the silicon dioxide is 0.1 to 1.0 μm, and relative to 100 weight portion of the polyolefin-based resins, is added Plus 10 to 15 weight portions silicon dioxide.

2. insulated electric conductor according to claim 1, wherein, the polyolefin-based resins are ethylene-vinyl acetate copolymerization What resin and polyvinyl resin were mixed.

3. insulated electric conductor according to claim 2, wherein, the ethylene-vinyl acetate copolymer resinses and polyethylene tree The Mixing ratio by weight of fat is 2:8～5:In the range of 5.