JP7143720B2 - insulated wire - Google Patents

Description

The present disclosure relates to insulated wires.

An insulated wire includes a conductor and an insulating layer. An insulating layer covers the conductor. Insulated wires are used in railway vehicles and the like. Insulated wires are used, for example, as power lines wired to motors and the like, control lines for controlling operation, and the like. Insulated wires are required to be excellent in flame retardancy, electrical insulation, and oil resistance.

Patent Literature 1 discloses a technique for improving the flame retardancy of an insulated wire by blending a polyolefin resin and a large amount of metal hydroxide in an insulating layer.

JP 2013-18932 A

Metal hydroxides are highly hygroscopic. Therefore, if a large amount of metal hydroxide is blended into the insulating layer as in the technique described in Patent Document 1, the electrical insulation of the insulated wire will deteriorate.
An object of one aspect of the present disclosure is to provide an insulated wire that is excellent in flame retardancy, electrical insulation, and oil resistance.

One aspect of the present disclosure is an insulated wire including a conductor, a first insulating layer covering the conductor, and a second insulating layer located on the outer peripheral side of the first insulating layer, wherein the first The insulating layer contains a first polymer and an inorganic filler blended in an amount of 150 parts by mass or less with respect to 100 parts by mass of the first polymer, and the second insulating layer contains an ethylene-vinyl acetate copolymer as a main component. and a metal hydroxide blended from 150 parts by mass to 250 parts by mass with respect to 100 parts by mass of the second polymer, wherein the first polymer is An insulated wire in which the first insulating layer and the second insulating layer are crosslinked, including a polyolefin that is a main component of the first polymer and has a melting point of 110° C. or higher, and an acid-modified polyolefin. .

An insulated wire that is one aspect of the present disclosure is excellent in flame retardancy, electrical insulation, and oil resistance.

1 is a cross-sectional view showing a configuration of an insulated wire 1; FIG. 3 is a cross-sectional view showing the configuration of an insulated cable 9; FIG.

Exemplary embodiments of the present disclosure are described with reference to the drawings.
1. Configuration of Insulated Wire (1-1) Conductor An insulated wire has a conductor. A known conductor can be appropriately selected and used as the conductor. Examples of conductor materials include copper and aluminum.

(1-2) First Insulating Layer The first insulating layer covers the conductor. The first insulating layer includes a first polymer. The first polymer contains polyolefin, which is the main component of the first polymer (hereinafter referred to as main component polyolefin). The main component of the first polymer means the component with the highest content among the polymer components contained in the first polymer. The first polymer may or may not contain a polyolefin other than the main component polyolefin.

The melting point of polyolefin, which is the main component, is 110° C. or higher. Since the melting point of the main component polyolefin is 110° C. or higher, the oil resistance of the first insulating layer is high. Differential scanning calorimetry (DSC) is used to measure the melting point of polyolefin, which is the main component.

Oil resistance can be evaluated by the following method. The specimen is immersed in IRM902 test oil heated to 100° C. for 72 hours. The smaller the rate of change in the tensile properties of the specimen after immersion with respect to the tensile properties of the specimen before immersion (hereinafter referred to as the rate of change in tensile resistance to oil), the higher the oil resistance.

If the melting point of the polyolefin as the main component is less than 110° C., the crystals of the polyolefin as the main component melt during the oil resistance test, and the oil easily diffuses into the first insulating layer. As a result, the rate of change in oil resistance tensile properties increases.
The crystallinity of polyolefin as the main component is preferably high. When the degree of crystallinity of the main component polyolefin is high, the oil resistance of the first insulating layer is even higher. As a method for increasing the crystallinity of the main component polyolefin, there is a method of using a crystalline polyolefin having a melting point of 110° C. or higher (preferably 120° C. or higher) as the main component polyolefin. Examples of crystalline polyolefins having a melting point of 110° C. or higher include low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, and combinations of one or more of these. mentioned. Among these, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene are preferable because they are less likely to collapse when the first insulating layer is crosslinked by a method such as electron beam irradiation.

The first polymer comprises an acid-modified polyolefin. The acid-modified polyolefin may or may not be the main polyolefin. Including the acid-modified polyolefin in the first polymer improves the electrical properties of the first insulating layer.

Polyolefin in acid-modified polyolefin, for example, one or more selected from the group consisting of polyethylene, ethylene-α-olefin, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, and vinyl acetate copolymer are mentioned. Examples of acids include maleic acid, maleic anhydride, fumaric acid and the like.

The first polymer preferably contains a rubber component. If the first polymer contains a rubber component, it will be more receptive to inorganic fillers. Examples of rubber components include ethylene-propylene copolymer rubber (EPR), ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), hydrogenated NBR (HNBR), acrylic rubber, Ethylene-acrylate copolymer rubber, ethylene octene copolymer rubber (EOR), ethylene-vinyl acetate copolymer rubber, ethylene-butene-1 copolymer rubber (EBR), butadiene-styrene copolymer rubber ( SBR), isobutylene-isoprene copolymer rubber (IIR), block copolymer rubber having a polystyrene block, urethane rubber, and the like.

Among rubber components, EOR and EBR do not have double bonds. Therefore, when the first polymer contains EOR or EBR, the risk of scorching during extrusion can be reduced. Also, EOR and EBR do not have polarity. Therefore, when the first polymer contains EOR or EBR, the electrical properties of the first insulating layer can be improved.

The first insulating layer may or may not contain an inorganic filler. When the first insulating layer contains an inorganic filler, the amount of the inorganic filler compounded in the first insulating layer is 150 parts by mass or less with respect to 100 parts by mass of the first polymer. When the amount of the inorganic filler to be blended is 150 parts by mass or less, the elongation at break of the first insulating layer is less likely to decrease. The amount of the inorganic filler compounded is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, relative to 100 parts by mass of the first polymer.

When the first insulating layer contains an inorganic filler, the amount of organic matter contained in the first insulating layer can be reduced. Reducing the amount of organic matter can reduce the toxic gas generated when the first insulating layer is burned. Poisonous gases include, for example, carbon monoxide and carbon dioxide. The amount of the inorganic filler compounded in the first insulating layer is preferably 20 parts by mass or more, more preferably 40 parts by mass or more based on 100 parts by mass of the first polymer component.

Examples of inorganic fillers include kaolinite, kaolin clay, calcined clay, talc, mica, wollastonite, silicates such as pyrophyllite, silica, alumina, zinc oxide, titanium oxide, calcium oxide, magnesium oxide, and the like. Examples thereof include oxides, carbonates such as calcium carbonate, zinc carbonate and barium carbonate, and hydroxides such as calcium hydroxide, magnesium hydroxide and aluminum hydroxide.

The amount of the inorganic filler compounded in the first insulating layer is 150 parts by mass or less with respect to 100 parts by mass of the first polymer. The electrical insulation of the layer is high.

The inorganic filler may consist of only one kind, or may be a mixture of two or more kinds. When the first insulating layer contains hydrophobic calcined clay or talc, the electrical properties of the first insulating layer are improved. Calcined clays and talcs do not contain carbon. Therefore, when the first insulating layer contains baked clay or talc, the amount of carbon monoxide generated when the first insulating layer is burned can be reduced.

It is preferable to subject the inorganic filler to surface treatment such as silane treatment. When the inorganic filler is subjected to surface treatment such as silane treatment, the adhesion between the inorganic filler and the first polymer is improved. As a result, the insulating performance of the first insulating layer is further improved.
The heat of fusion of the first insulating layer is preferably 65 J/g or more. When the heat of fusion of the first insulating layer is 65 J/g or more, the oil resistance of the first insulating layer is further improved.

The first insulating layer is preferably crosslinked. When the first insulating layer is crosslinked, the oil resistance is improved. The cross-linking method is not particularly limited. Cross-linking methods include, for example, chemical cross-linking, irradiation cross-linking, and cross-linking utilizing other chemical reactions. For chemical cross-linking, for example, organic peroxides, sulfur compounds, silanes, and the like are used. In irradiation crosslinking, for example, an electron beam, radiation, or the like is used.

If necessary, the first insulating layer contains a cross-linking aid, a flame retardant aid, an ultraviolet absorber, a light stabilizer, a softening agent, a lubricant, a coloring agent, a reinforcing agent, a surfactant, a plasticizer, a metal chelating agent, Blowing agents, compatibilizers, processing aids, stabilizers, and the like may also be included.

(1-3) Second Insulating Layer The second insulating layer is positioned closer to the outer periphery than the first insulating layer. The second insulating layer, for example, is in contact with the first insulating layer. Further, another layer may be interposed between the second insulating layer and the first insulating layer.

The second insulating layer is made of a non-halogen flame-retardant resin composition. The second insulating layer contains a flame retardant. A non-halogen flame retardant is preferred as the flame retardant. Halogen-free flame retardants do not generate halogen gas when burned. Metal hydroxides are preferred as non-halogen flame retardants. Examples of metal hydroxides include magnesium hydroxide and aluminum hydroxide.

As the non-halogen flame retardant, one that hardly generates phosphine gas and cyan gas, which are harmful to the human body, is preferable. Examples of non-halogen flame retardants that easily generate phosphine gas and cyan gas include phosphorus-based flame retardants such as red phosphorus and triazine-based flame retardants such as melamine cyanurate.

Non-halogen flame retardants include, for example, clay, silica, zinc stannate, zinc borate, calcium borate, dolomide hydroxide, and silicone.
Considering the dispersibility of the flame retardant, etc., the flame retardant can be surface-treated. Substances used for surface treatment include silane coupling agents, titanate coupling agents, fatty acids, and the like. Examples of fatty acids include stearic acid and the like.

The blending amount of the flame retardant is not particularly limited. The blending amount of the flame retardant is preferably 150 parts by mass or more and 300 parts by mass or less, more preferably 150 parts by mass or more and 250 parts by mass or less with respect to 100 parts by mass of the second polymer. When the blending amount of the flame retardant is 150 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the second polymer, the flame retardancy of the second insulating layer is further enhanced.

When a metal hydroxide is included as the flame retardant, the amount of the metal hydroxide compounded is preferably 150 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the second polymer. When the blending amount of the metal hydroxide is 150 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the second polymer, the flame retardancy of the second insulating layer is further enhanced.

The second insulating layer includes a second polymer. The second polymer includes, for example, polyolefin. The second polymer preferably contains an ethylene-vinyl acetate copolymer as a main component. The main component of the second polymer means the component with the highest content among the polymer components contained in the second polymer.

An ethylene-vinyl acetate copolymer is preferable because it causes an endothermic reaction due to deacetic acid during combustion. The second polymer may contain only one type of ethylene vinyl acetate copolymer, or may contain a mixture of multiple types of ethylene vinyl acetate copolymers.

The second polymer may include polyolefins other than ethylene vinyl acetate copolymers. Examples of polyolefins other than ethylene-vinyl acetate copolymers include acid-modified ethylene-α-olefins. When the second polymer contains the acid-modified ethylene-α-olefin, the low temperature resistance of the second insulating layer is improved.

The second insulating layer is preferably crosslinked. When the second insulating layer is crosslinked, dripping during combustion can be suppressed. The cross-linking method is not particularly limited. Cross-linking methods include, for example, chemical cross-linking, irradiation cross-linking, and cross-linking utilizing other chemical reactions. For chemical cross-linking, for example, organic peroxides, sulfur compounds, silanes, and the like are used. In irradiation crosslinking, for example, an electron beam, radiation, or the like is used.

The second insulating layer, if necessary, contains a cross-linking agent, a cross-linking aid, a flame retardant aid, an ultraviolet absorber, a light stabilizer, a softening agent, a lubricant, a coloring agent, a reinforcing agent, a surfactant, an inorganic filler, Antioxidants, plasticizers, metal chelating agents, foaming agents, compatibilizers, processing aids, stabilizers and the like may also be included.

The insulated wire of the present disclosure has, for example, the configuration shown in FIG. The insulated wire 1 includes a conductor 3 , a first insulating layer 5 and a second insulating layer 7 . A first insulating layer 5 covers the conductor 3 . The second insulating layer 7 is located on the outer peripheral side of the first insulating layer 5 . In the form shown in FIG. 1 , the second insulating layer 7 is in contact with the first insulating layer 5 .

2. Configuration of Insulated Cable The insulated cable of the present disclosure has, for example, the configuration shown in FIG. The insulated cable 9 has at least one insulated wire 1 and a sheath 11 . In the form shown in FIG. 2 , the insulated cable 9 comprises two insulated wires 1 . The insulated wire 1 is housed inside the sheath. As the material of the sheath, for example, the same material as that of the second insulating layer 7 can be used.

3. Examples (3-1) Production of insulated wires Insulated wires of Examples 1 to 7 and Comparative Examples 1 to 3 were produced as follows. The raw materials shown in the row of "first insulating layer" in Table 1 or Table 2 are kneaded using a 14-inch open roll so as to have the corresponding compounding ratio, and pelletized to obtain the material of the first insulating layer. manufactured. In addition, the raw materials shown in the row of "Second insulating layer" in Table 1 or Table 2 are kneaded using a 14-inch open roll so as to have the corresponding compounding ratio, and pelletized to form the second insulating layer. materials were manufactured.

表１及び表２における配合量の単位は質量部である。表１及び表２において「EVA¹⁾」は、三井デュポンケミカル製のＥＶ２７０である。「EVA¹⁾」はエチレン酢酸ビニル共重合体である。表１及び表２において「EVA²⁾」は、三井デュポンケミカル製のＶ９０００である。「EVA²⁾」はエチレン酢酸ビニル共重合体である。

The unit of the compounding amount in Tables 1 and 2 is parts by mass. In Tables 1 and 2, "EVA ¹⁾ " is EV270 manufactured by Mitsui DuPont Chemical. "EVA ¹⁾ " is an ethylene vinyl acetate copolymer. "EVA ²⁾ " in Tables 1 and 2 is V9000 manufactured by Mitsui DuPont Chemical. "EVA ²⁾ " is an ethylene vinyl acetate copolymer.

In Tables 1 and 2, "modified polyolefin ³⁾ " is Tafuma MH7020 manufactured by Mitsui Chemicals. "Modified polyolefin ³⁾ " is an acid-modified polyolefin obtained by modifying an ethylene-α-olefin copolymer with maleic anhydride. In Tables 1 and 2, "Magnesium hydroxide ⁴⁾ " is Mugsees S3 manufactured by Kashima Kagaku Kogyo Co., Ltd. "Magnesium hydroxide4 ⁾ " corresponds to metal hydroxides and non-halogen flame retardants.

In Tables 1 and 2, "PE ⁵⁾ " is SP4030 made by Prime Polymer. "PE ⁵⁾ " is polyethylene. The melting point of "PE ⁵⁾ " is 127°C. "PE ⁶⁾ " in Tables 1 and 2 is SP1510 made by Prime Polymer. "PE ⁶⁾ " is polyethylene. The melting point of "PE ⁶⁾ " is 117°C.

In Tables 1 and 2, "EBR ⁷⁾ " is Tafuma DF840 manufactured by Mitsui Chemicals. "EBR ⁷⁾ " is an ethylene-butene-1 copolymer rubber. "EBR ⁷⁾ " corresponds to the rubber component. The melting point of "EBR ⁷⁾ " is 66°C. "Modified Polyolefin ⁸⁾ " in Tables 1 and 2 is Bondine LX4110 manufactured by Arkema. "Modified polyolefin ⁸⁾ " is an acid-modified polyolefin obtained by modifying an ethylene-ethyl acrylate copolymer with maleic anhydride. The melting point of "modified polyolefin ⁸⁾ " is 107°C.

"Inorganic filler ⁹⁾ " in Tables 1 and 2 is Translink 37 manufactured by BASF. "Inorganic fillers9 ⁾ " are calcined clays. In Tables 1 and 2, "Inorganic filler ¹⁰⁾ " is Micro Ace L1 manufactured by Nippon Talc. "Inorganic fillers10 ⁾ " are calcined clays. In Tables 1 and 2, "PE ¹¹⁾ " is Novatec ZF33 manufactured by Nippon Polyethylene. "PE ¹¹⁾ " is polyethylene. The melting point of "PE ¹¹⁾ " is 107°C.

In Table 1, "PE ⁵⁾ ", "PE ⁶⁾ ", "EBR ⁷⁾ ", "modified polyolefin ⁸⁾ " and "modified polyolefin ³⁾ " correspond to the first polymer. In Examples 1, 3 to 6, "PE ⁵⁾ " corresponds to the main component polyolefin. In Examples 2 and 7, "PE ⁶⁾ " corresponds to the main component polyolefin. In Table 1, "EVA ¹⁾ " and "EVA ²⁾ " correspond to the second polymer.

In Tables 1 and 2, "Other" is a mixture of each component according to the compounding ratio shown in Table 3.

次に、４０ｍｍ押出機を用いて２層押出を行い、導体を被覆することで、絶縁電線を得た。絶縁電線は、上記のように製造した第１絶縁層の材料から成る第１絶縁層と、上記のように製造した第２絶縁層の材料から成る第２絶縁層とを備えていた。導体は、構成３７本/０．１８ｍｍの錫めっき導体であった。製造した絶縁電線は、図１に示す構造を備えていた。次に、５Ｍｒａｄの電子線を照射することで、第１絶縁層及び第２絶縁層を架橋した。

Next, an insulated wire was obtained by carrying out two-layer extrusion using a 40 mm extruder and covering the conductor. The insulated wire had a first insulation layer of the first insulation layer material produced as described above and a second insulation layer of the second insulation layer material produced as described above. The conductors were tinned conductors of configuration 37 lines/0.18 mm. The insulated wire produced had the structure shown in FIG. Next, the first insulating layer and the second insulating layer were crosslinked by irradiation with an electron beam of 5 Mrad.

(3-2) Evaluation of insulated wire The insulated wires of each example and each comparative example were evaluated as follows.
(i) Evaluation of Tensile Strength and Breaking Elongation A tube was obtained by removing the conductor from the insulated wire. This tube was used as a test piece. The specimen consists of a first insulating layer and a second insulating layer. A tensile test was performed on the specimen at a displacement rate of 250 mm/min to measure tensile strength and elongation at break. Judgments were made regarding elongation at break. If the elongation at break was 150% or more, the judgment result was given as "good", and otherwise as "poor". The measurement results of tensile strength and elongation at break are shown in Tables 1 and 2 above. In addition, Tables 1 and 2 show the results of the judgment regarding elongation at break.

(ii) Evaluation of Oil Resistant Tensile Strength and Oil Elongation Change Rate After the evaluation of (i) above, the specimen was immersed in IRM902 heated to 100° C. for 72 hours. After that, the specimen was left at room temperature for about 16 hours. Thereafter, the tensile strength and elongation at break of the specimen were measured in the same manner as in (i) above. Let the tensile strength measured at this time be the tensile strength after immersion. Moreover, let the breaking elongation measured at this time be the breaking elongation after immersion.

The rate of change in tensile strength after immersion (hereinafter referred to as rate of change in oil resistance tensile strength) with respect to the tensile strength measured in (i) above was calculated. Also, the rate of change in elongation at break after immersion (hereinafter referred to as rate of change in elongation at break in oil) relative to the elongation at break measured in (i) above was calculated.

Judgment was made on the rate of change in tensile strength in oil resistance and the rate of change in elongation at break in oil resistance. If the absolute value of the rate of change in tensile strength resistance to oil was 30% or less, the judgment result regarding the rate of change in tensile strength resistance to oil was given as "O", and otherwise as "x".

If the absolute value of the change rate of elongation at break under oil was 40% or less, the determination result regarding the change rate of elongation at break under oil was given as "O", and otherwise as "x". Tables 1 and 2 show the judgment results regarding the rate of change in tensile strength in oil resistance and the rate of change in elongation at break in oil resistance.

(iii) Flame-retardant test A flame-retardant test was performed according to EN45545-2. A specific method is as follows. A burner flame was applied to the vertically supported insulated wire for 1 minute and then the flame was removed. Next, the distance between the upper fixed portion and the upper end of the carbonized portion was measured. Also, the distance between the upper fixing portion and the lower end of the carbonized portion was measured.

If the distance between the upper fixing portion and the upper end of the carbonized portion was 50 mm or more and the distance between the upper fixing portion and the lower end of the carbonized portion was less than 540 mm, the determination result of the flame retardancy test was given as "○".
A horizontal flame retardant test was carried out in conformity with JISC3005 for the insulated wires for which the judgment result of the above test was not "○". When self-extinguishing occurred within 15 seconds, the judgment result of the flame retardance test was given as "Δ", and when it did not self-extinguish within 15 seconds, the judgment result of the flame resistance test was given as "x". The determination results of the flame retardancy test are shown in Tables 1 and 2 above.

(iv) Measurement of heat of fusion A first insulating layer was cut out from an insulated wire and used as a test piece. Measurement was performed from 0°C to 160°C by a differential scanning calorimetry (DSC) method. The heating rate was set to 10°C/min, and the heat of fusion was determined in the range of 50°C to 140°C.

(v) Comprehensive evaluation All of the determination results regarding elongation at break, the determination result regarding oil resistance tensile strength change rate, the determination result regarding oil resistance breaking elongation change rate, and the judgment result regarding flame retardancy test are all "○". In some cases, the result of the comprehensive evaluation was set as "A". If the evaluation results included at least one "Δ" but not "X", the overall evaluation result was "○". When even one of the evaluation results included "x", the result of comprehensive evaluation was set to "x". The results of comprehensive evaluation are shown in Tables 1 and 2 above.

In Examples 1 to 7, the results of the comprehensive evaluation were "excellent" or "good". On the other hand, in Comparative Examples 1 to 3, the overall evaluation result was "x".
4. Other Embodiments Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications can be made.

(1) A function of one component in each of the above embodiments may be assigned to a plurality of components, or a function of a plurality of components may be performed by one component. Also, part of the configuration of each of the above embodiments may be omitted. Also, at least part of the configuration of each of the above embodiments may be added, replaced, etc. with respect to the configuration of the other above embodiments. It should be noted that all aspects included in the technical idea specified by the wording in the claims are embodiments of the present disclosure.

(2) In addition to the insulated wire described above, the present disclosure can also be realized in various forms such as a system having the insulated wire as a component, a method for manufacturing an insulated wire, a method for manufacturing an insulated cable, and the like.

DESCRIPTION OF SYMBOLS 1... Insulated wire, 3... Conductor, 5... First insulating layer, 7... Second insulating layer, 9... Insulated cable, 11... Sheath

Claims (3)

a conductor;
a first insulating layer covering the conductor;
a second insulating layer located on the outer peripheral side of the first insulating layer;
An insulated wire comprising
The first insulating layer is
a first polymer;
an inorganic filler blended in an amount of 150 parts by mass or less with respect to 100 parts by mass of the first polymer;
including
The second insulating layer is
a second polymer containing an ethylene-vinyl acetate copolymer as a main component;
150 parts by mass or more and 250 parts by mass or less of a metal hydroxide blended with 100 parts by mass of the second polymer;
Consisting of a non-halogen flame-retardant resin composition containing
The first polymer is
a polyolefin that is the main component of the first polymer and has a melting point of 110° C. or higher;
an acid-modified polyolefin;
including
The heat of fusion of the first insulating layer is 65 J/g or more,
The insulated wire in which the first insulating layer and the second insulating layer are crosslinked. The insulated wire according to claim 1 ,
The polyolefin in the acid-modified polyolefin is at least one selected from the group consisting of polyethylene, ethylene-α-olefin, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, and vinyl acetate copolymer. Includes insulated wire. The insulated wire according to claim 1 or 2 ,
The insulated wire, wherein the inorganic filler contains at least one of clay and talc.

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