Insulated Wire

Abstract

To provide an insulated wire which can suppress occurrence of cloudiness in a peripheral translucent member even when heated.SOLUTION: An insulated wire includes a conductor and an insulating layer covering the outer surface of the conductor, wherein the insulating layer contains a resin component and a stearic acid as a lubricant, the resin component contains polyethylene as a main component, and the resin component has a melting temperature of 110°C or lower and a quantity of heat of fusion of 80 J / g or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to insulated wire. [Background technology]

[0002] Patent Document 1 discloses an automobile wire harness having a layer made of a resin coating material crosslinked from a resin composition containing 90 to 100 parts by mass of an ethylene-vinyl acetate copolymer (A), 15 to 30 parts by mass of a bromine-based flame retardant (B), 5 to 15 parts by mass of antimony trioxide (C), 6 to 12 parts by mass of a benzimidazole-based antioxidant (D), 2 to 4 parts by mass of a phenol-based antioxidant (E), 2 to 4 parts by mass of a thioether-based antioxidant (F), 0.5 to 2 parts by mass of a copper inhibitor (G), and 3 to 6 parts by mass of a crosslinking auxiliary (H). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-014794 A Summary of the Invention [Problem to be solved by the invention]

[0004] An insulated wire includes a conductor and an insulating layer that covers the outer surface of the conductor.

[0005] Insulated electric wires are also used in automobiles, for example, as in the automobile wire harness disclosed in Patent Document 1. However, when the insulated electric wire is used, for example, for wiring of an automobile light and is heated by the light for a long period of time, clouding may occur in the translucent member of the light disposed around the insulated electric wire.

[0006] In view of the above, an object of the present disclosure is to provide an insulated electric wire that can suppress the occurrence of clouding on a surrounding light-transmitting member even when heated. [Means for solving the problem]

[0007] The insulated wire of the present disclosure comprises a conductor and an insulating layer covering an outer surface of the conductor; The insulating layer contains a resin component and stearic acid as a lubricant, The resin component contains polyethylene as a main component, The resin component has a melting temperature of 110° C. or less and a heat of fusion of 80 J / g or less. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide an insulated electric wire that can suppress the occurrence of clouding on a surrounding light-transmitting member even when heated. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of an insulated wire according to one embodiment of the present disclosure taken along a plane perpendicular to the longitudinal direction. [Figure 2A] FIG. 2A is an explanatory diagram of the relationship between the crystallinity of a resin component and additives. [Figure 2B] FIG. 2B is an explanatory diagram of the relationship between the crystallinity of the resin component and the additives. [Diagram 3] FIG. 3 is an explanatory diagram of a haze test device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The embodiments for carrying out the invention are described below.

[0011] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be described. In the following description, the same or corresponding elements are denoted by the same reference numerals, and the same description thereof will not be repeated.

[0012] (1) An insulated wire according to one embodiment of the present disclosure includes a conductor and an insulating layer covering an outer surface of the conductor; The insulating layer contains a resin component and stearic acid as a lubricant, The resin component contains polyethylene as a main component, The resin component has a melting temperature of 110° C. or less and a heat of fusion of 80 J / g or less.

[0013] When the resin component contains polyethylene as a main component and has a melting temperature of 110° C. or lower, the crystallinity of the resin component is sufficiently low and the side chains of the resin component can contain a sufficient amount of branched structures. Therefore, even when the insulated wire is heated and exposed to high temperatures, the additive is prevented from being released to the outside of the insulating layer, and gas generation and clouding of light-transmitting members such as lights placed around the wire due to the generated gas can be prevented.

[0014] When the resin component contains polyethylene as a main component and has a heat of fusion of 80 J / g or less, the resin component has sufficiently low crystallinity and can contain a sufficient amount of branched structures in the side chains of the resin component. Therefore, even when the insulated wire is heated and exposed to high temperatures, the additive is prevented from being released outside the insulating layer, and gas generation and clouding of light-transmitting members such as lights placed around the insulated wire due to the generated gas can be prevented.

[0015] In addition, when the insulating layer contains stearic acid as a lubricant, gas generation when the insulated wire is heated and clouding of the surrounding light-transmitting member due to the generated gas are particularly likely to occur. In contrast, the insulated wire according to one aspect of the present disclosure can suppress the generation of such gas and the clouding of the surrounding light-transmitting member even when heated. Therefore, when the insulating layer contains stearic acid as a lubricant, it is possible to exhibit a particularly high effect in suppressing the clouding of the surrounding light-transmitting member.

[0016] (2) In accordance with ISO 6452, the glass plate may have a haze value of 15% or less when placed in a container covered with a glass plate, heated at 100°C for 16 hours, and then left in an air atmosphere for 1 hour.

[0017] When the above test is performed, if the haze value of the glass plate is 15% or less, it can be said that the insulated wire suppresses gas generation even when heated for a long period of time, and is particularly capable of suppressing clouding of the translucent member arranged around the insulated wire.

[0018] (3) The resin component may have a melt mass flow rate of more than 1.0 g / 10 min.

[0019] When the melt mass flow rate of the resin component is greater than 1.0 g / 10 min, the fluidity of the resin component when forming the insulated wire is increased, and the processability when forming the insulated wire is improved.

[0020] (4) It may be used for wiring in automobile headlights.

[0021] Wiring in an automobile headlight may be heated by the headlight during use. It is particularly required to prevent the occurrence of fogging in a light-transmitting member used in the headlight. According to the insulated wire according to one embodiment of the present disclosure, even when heated for a long period of time, gas generation can be suppressed, and the occurrence of fogging in the light-transmitting member disposed around the insulated wire can be suppressed. Therefore, the insulated wire according to one embodiment of the present disclosure can be particularly effective when used in wiring in an automobile headlight.

[0022] [Details of the embodiment of the present disclosure] Specific examples of an insulated wire according to an embodiment of the present disclosure (hereinafter, referred to as the present embodiment) will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. [Insulated wire] Fig. 1 shows an example of the cross section perpendicular to the longitudinal direction of an insulated electric wire according to the present embodiment. The direction perpendicular to the paper surface in Fig. 1 is the longitudinal direction of the insulated electric wire.

[0023] As shown in FIG. 1, an insulated wire 10 of the present embodiment can have a conductor 11 and an insulating layer 12 that covers the outer surface of the conductor 11. (1) Regarding the components contained in the insulated wire Each member contained in the insulated wire of the present embodiment will be described below. (1-1) Conductor The conductor 11 can be made of a single metal wire or multiple metal wires. When the conductor 11 has multiple metal wires, the multiple metal wires can be twisted together. In other words, when the conductor 11 has multiple metal wires, the conductor 11 can be a twisted wire of multiple metal wires.

[0024] The material of the conductor 11 is not particularly limited, but may be one or more conductive materials selected from, for example, copper, soft copper, silver-plated soft copper, nickel-plated soft copper, tin-plated soft copper, and the like. (1-2) Insulating layer (1-2-1) Resin component 1, the insulating layer 12 can cover the outer surface of the conductor 11, specifically, the outer surface along the longitudinal direction of the insulated wire 10. The insulating layer 12 can contain a resin component. The resin component contains polyethylene as a main component. The resin component may be crosslinked or may not be crosslinked.

[0025] The resin component containing polyethylene as a main component means that the resin component contains polyethylene in the largest amount by mass. In this case, the resin component preferably contains 65 mass% or more of polyethylene. Since the resin component can be composed only of polyethylene, the resin component can contain 100 mass% or less of polyethylene. (Melting temperature, heat of fusion) The inventors of the present invention have investigated the cause of clouding of the light-transmitting member of an automobile light when the insulated electric wire is used for wiring the light and heated for a long time by the light. The light-transmitting member refers to a member that protects a light source such as a light, is disposed on an optical path through which light from the light passes, and transmits the light. As a result, they have found that when the insulated electric wire is heated, additives such as lubricants contained in the insulating layer of the insulated electric wire volatilize and become gas, which condenses or solidifies and adheres to the light-transmitting member, causing the light-transmitting member to cloud.

[0026] Based on the above findings, the inventors of the present invention conducted further research and discovered that the crystallinity of the resin component contained in the insulating layer can control the volatility of additives such as lubricants, and can suppress gas generation and clouding of the translucent member due to gas generation even when the insulated electric wire is heated for a long period of time by a light or the like, thereby completing the present invention.

[0027] The relationship between the crystallinity of the resin component of the insulating layer and the additives is shown using Figures 2A and 2B. Figures 2A and 2B show an additive 21 such as a lubricant, and a resin component 22. As shown in Figures 2A and 2B, the resin component 22 has a main chain 221 and a side chain 222. Note that the resin component may be crosslinked, and in the case of crosslinking, bonds are also included between the main chains 221, etc.

[0028] The insulating layer 201 shown in FIG. 2A and the insulating layer 202 shown in FIG. 2B have different crystallinity of the contained resin component 22, and the resin component contained in the insulating layer 201 has a lower crystallinity than the insulating layer 202.

[0029] 2B, the resin component contained therein has high crystallinity, and therefore the branched structure is reduced in the side chains 222. Therefore, when the insulating layer 202 is heated and exposed to a high temperature, the molecular motion of the additive 21 becomes active, and the additive 21 is easily released to the outside through the gaps in the resin component.

[0030] In contrast, in insulating layer 201 shown in Fig. 2A, the crystallinity of the resin component contained therein is low, so that side chains 222 of resin component 22 include a branched structure as shown in Fig. 2A. Therefore, even if insulating layer 201 is heated and exposed to high temperatures, causing active molecular motion of additive 21, the molecular motion is inhibited by side chains 222 having a branched structure. As a result, additive 21 is less likely to be released to the outside even when insulating layer 201 is heated.

[0031] Therefore, it is preferable that the resin component contained in the insulating layer 12 has low crystallinity. The crystallinity of the resin component contained in the insulating layer can be evaluated by the melting temperature and the heat of fusion. The melting temperature and the heat of fusion of the resin component can be obtained by performing DSC (Differential Scanning Calorimetry) measurement on the insulating layer.

[0032] The melting temperature of the resin component is preferably 110° C. or lower, and more preferably 107° C. or lower.

[0033] When the resin component contains polyethylene as a main component and has a melting temperature of 110° C. or lower, the crystallinity of the resin component is sufficiently low and the side chains of the resin component can contain a sufficient amount of branched structures. Therefore, even when the insulated wire is heated and exposed to high temperatures, the additive is prevented from being released to the outside of the insulating layer, and gas generation and clouding of light-transmitting members such as lights placed around the wire due to the generated gas can be prevented.

[0034] The lower limit of the melting temperature of the resin component is not particularly limited, but is preferably, for example, 55° C. or higher, and more preferably 60° C. or higher.

[0035] The heat of fusion of the resin component is preferably 80 J / g or less, and more preferably 75 J / g or less.

[0036] When the resin component contains polyethylene as a main component and has a heat of fusion of 80 J / g or less, the resin component has sufficiently low crystallinity and can contain a sufficient amount of branched structures in the side chains of the resin component. Therefore, even when the insulated wire is heated and exposed to high temperatures, the additive is prevented from being released outside the insulating layer, and gas generation and clouding of light-transmitting members such as lights placed around the insulated wire due to the generated gas can be prevented.

[0037] The lower limit of the heat of fusion of the resin component is not particularly limited, but is preferably, for example, 30 J / g or more, and more preferably 32 J / g or more. (Melt Mass Flow Rate) The resin component preferably has a melt mass flow rate (MFR) of more than 1.0 g / 10 min, more preferably 1.1 g / 10 min or more. When the resin component has a melt mass flow rate of more than 1.0 g / 10 min, the resin component has high fluidity when the insulated wire is formed, and the processability when the insulated wire is formed can be improved.

[0038] The upper limit of the melt mass flow rate of the resin component is not particularly limited, but is preferably 5.0 g / 10 min or less, and more preferably 2.0 g / 10 min or less, for example. By setting the melt mass flow rate within the above range, the fluidity of the resin component can be prevented from becoming excessively high when forming the insulated electric wire, and the processability when forming the insulated electric wire can be particularly improved. (1-2-2) Additives In addition to the above resin components, the insulating layer 12 may contain various additives, such as one or more additives selected from a flame retardant, an antioxidant, a lubricant, an acid acceptor, and the like. (lubricant) As described above, the raw material of the gas that is generated when the insulated wire is heated and causes the clouding of the light-transmitting member is mainly a lubricant such as stearic acid. For this reason, it is preferable that the insulating layer 12 contains stearic acid as a lubricant. When the insulating layer 12 contains stearic acid as a lubricant, the gas generation and the clouding of the light-transmitting member caused by the gas generation are easily caused when the insulated wire is heated. In contrast, the insulated wire of the present embodiment can suppress the generation of the gas and the clouding of the light-transmitting member disposed around the insulated wire even when the wire is heated. For this reason, when the insulating layer contains stearic acid as a lubricant, it is possible to exhibit a particularly high effect in suppressing the clouding of the light-transmitting member around the insulated wire.

[0039] In this specification, stearic acid does not include stearates such as zinc stearate formed by reacting with a base, or calcium stearate.

[0040] There is no particular limitation on the content of stearic acid in the insulating layer 12. For example, when the resin component is taken as 100 parts by mass, the insulating layer 12 preferably contains stearic acid in an amount of more than 0 part by mass and not more than 2.0 parts by mass, and more preferably contains 0.1 parts by mass or more and not more than 1.5 parts by mass.

[0041] When the insulating layer 12 has a resin component of 100 parts by mass, the content of stearic acid is greater than 0 parts by mass, which makes it easier to peel the insulating layer 12 from the conductor 11 and improves the processability of the insulated wire. When the insulating layer 12 has a resin component of 100 parts by mass, the content of stearic acid is 2.0 parts by mass or less, which makes it possible to prevent precipitation of stearic acid on the surface of the insulating layer 12, etc. (Flame retardant) The flame retardant is not particularly limited, and for example, a halogen-based flame retardant can be used.

[0042] The halogen-based flame retardant imparts flame retardancy to the insulating layer of the insulated wire, and examples of the halogen-based flame retardant include bromine-based flame retardants and chlorine-based flame retardants.

[0043] Examples of bromine-based flame retardants include ethylene bistetrabromophthalimide, ethylene bis(pentabromophenyl), tetrabromoethane, tetrabromobisphenol A, hexabromobenzene, decabromobiphenyl ether, tetrabromophthalic anhydride, polydibromophenylene oxide, hexabromocyclodecane, and ammonium bromide.

[0044] Examples of chlorine-based flame retardants include chlorinated paraffin, chlorinated polyethylene, chlorinated polyphenol, and perchlorpentacyclodecane.

[0045] Of these halogen-based flame retardants, bromine-based flame retardants are preferred, with ethylene bis(tetrabromophthalimide) (e.g., Albemarle's "Scitex BT93") and ethylene bis(pentabromophenyl) (e.g., Albemarle's "Scitex 8010") being more preferred. The halogen-based flame retardants may be used alone or in combination of two or more kinds.

[0046] There is no particular lower limit for the content of the halogen-based flame retardant in the insulating layer 12. For example, when the resin component is taken as 100 parts by mass, the content of the halogen-based flame retardant in the insulating layer 12 is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more. When the resin component is taken as 100 parts by mass, the insulating layer 12 contains 1 part by mass or more of the halogen-based flame retardant, so that the insulating layer 12 can be given sufficient flame retardancy.

[0047] There is no particular upper limit to the content of the halogen-based flame retardant in the insulating layer 12. For example, when the resin component is taken as 100 parts by mass, the content of the halogen-based flame retardant in the insulating layer 12 is preferably 30 parts by mass or less, and more preferably 25 parts by mass or less. When the resin component is taken as 100 parts by mass, the insulating layer 12 contains 30 parts by mass or less of the halogen-based flame retardant, thereby improving the adhesion between the insulating layer and the conductor.

[0048] In addition to the above halogen-based flame retardants, the insulating layer 12 may contain phosphorus-based flame retardants, nitrogen-based flame retardants, and non-halogen-based flame retardants such as magnesium hydroxide, aluminum hydroxide, antimony trioxide, etc. The content of the non-halogen-based flame retardant is also not particularly limited, but the content of the non-halogen-based flame retardant is preferably 10 parts by mass or less when the resin component is taken as 100 parts by mass. (Antioxidants) The antioxidant is preferably a hindered phenol-based antioxidant. Examples of the hindered phenol-based antioxidant include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide], benzenepropanoic acid ,3,5-bis(1,1-dimethylethyl)-4-hydroxy,C7-C9 side chain alkyl esters, 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 3,3',3",5,5'5"-hexa-tert-butyl-a,a',a"-(mesitylene-2,4,6-tolyl)tri-p-cresol, calcium diethylbis[[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl ]phosphonate], 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris[(4-tert-butyl-3-hydroxy 2,6-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, 2,6-di-tert-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 3,9-bis[2-(3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propoxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro(5,5)undecane. These may be used alone or in combination of two or more.

[0049] There is no particular lower limit for the content of the antioxidant in the insulating layer 12. For example, when the resin component is taken as 100 parts by mass, the content of the antioxidant in the insulating layer 12 is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more. When the resin component is taken as 100 parts by mass, the insulating layer 12 contains 0.5 parts by mass or more of the antioxidant, so that the insulating layer 12 can be provided with sufficient antioxidant properties.

[0050] There is no particular upper limit to the content of the antioxidant in the insulating layer 12. For example, when the resin component is taken as 100 parts by mass, the content of the antioxidant in the insulating layer 12 is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less. When the resin component is taken as 100 parts by mass, the insulating layer 12 contains 10 parts by mass or less of the antioxidant, thereby making it possible to suppress blooming and the like. (acid acceptor) As the acid acceptor, one or more selected from iron oxide, titanium oxide, magnesium oxide, aluminum oxide, silicon dioxide, and zinc oxide can be used.

[0051] There is no particular lower limit for the content of the acid acceptor in the insulating layer 12. For example, when the resin component in the insulating layer 12 is taken as 100 parts by mass, the content of the acid acceptor in the insulating layer 12 is preferably 0.1 parts by mass or more, and more preferably 5 parts by mass or more.

[0052] There is no particular upper limit on the content of the acid acceptor in the insulating layer 12. For example, when the resin component in the insulating layer 12 is taken as 100 parts by mass, the content of the acid acceptor in the insulating layer 12 is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less. (2) Characteristics and suitable applications of insulated wire (2-1) Hayes According to the insulated wire of the present embodiment, even when heated, generation of gas can be suppressed, and clouding of the translucent member disposed around the insulated wire can be suppressed.

[0053] There is no particular limitation on the degree to which the generation of such gas is suppressed and the generation of fogging on the light-transmitting member is suppressed. For example, in accordance with ISO 6542, when an insulated electric wire is placed in a container covered with a glass plate, heated at 100°C for 16 hours, and then left in the air for 1 hour, the haze value of the glass plate is preferably 15% or less, and more preferably 14% or less.

[0054] When the above test was performed, if the haze value of the glass plate was 15% or less, it could be said that the generation of gas was suppressed even when the glass plate was heated for a long period of time, and the occurrence of clouding of the translucent member arranged around the glass plate was sufficiently suppressed.

[0055] In addition, the lower limit of the haze value of the glass plate when the above test is performed is not particularly limited, but may be equal to or greater than 0. However, since it may be difficult to achieve a haze value of 0, the above haze value is preferably equal to or greater than 1%.

[0056] The above test can be carried out based on the ISO6542 standard, and can be carried out, for example, using a haze test apparatus shown in Fig. 3. Fig. 3 is a schematic cross-sectional view of the haze test apparatus taken along a plane passing through the central axis.

[0057] The haze test device has a structure in which a beaker 31 with an inner diameter of φ83 mm and a height of 190 mm is laminated, a silicon packing 32, a 100 mm×100 mm glass plate 33, filter paper 34, and a cooling plate 35. The haze value can be measured by the following procedure.

[0058] An oil bath is filled with silicone oil to a height of 130 mm and heated to 100°C in advance.

[0059] Next, the insulated wire 10 to be evaluated is placed in the beaker 31 of the haze test device, and the packing 32, glass plate 33, filter paper 34, and cooling plate 35 are layered at the upper opening of the beaker 31, and the beaker is covered with a lid. The cooling plate 35 can be configured so that water at 21° C. flows inside to cool the glass plate 33 and the like.

[0060] The haze test apparatus is then placed in an oil bath and heated for 16 hours.

[0061] Next, the haze test device is taken out of the oil bath and left to stand for one hour in an air atmosphere, for example, in an environment with a temperature of 23° C. and a relative humidity of 50% RH.

[0062] The glass plate 33 can then be removed and the haze measured. (2-2) Suitable Uses The use of the insulated wire of the present embodiment is not particularly limited, but it is preferable that the insulated wire be used for wiring in automobile headlights.

[0063] Wiring in an automobile headlight may be heated by the headlight during use. It is particularly required to prevent the occurrence of fogging in the light-transmitting member used in the headlight. The insulated wire of the present embodiment can suppress the generation of gas even when heated for a long period of time, and can suppress the occurrence of fogging in the light-transmitting member arranged around the wire. Therefore, the insulated wire of the present embodiment can be particularly effective when used in wiring in an automobile headlight. EXAMPLES

[0064] The present invention will be described below with reference to specific examples, but is not limited to these examples. (Evaluation method) First, the evaluation method of the insulated wires produced in the following experimental examples will be described. (1) Melting temperature, heat of fusion The melting temperature and heat of fusion of the resin component contained in the insulating layer were measured and calculated using a DSC (Shimadzu Corporation; heat flux differential scanning calorimeter DSC-50) according to the method described below.

[0065] The insulating layer was peeled off from the insulated wire produced in each of the following experimental examples, and 5 mg of the insulating layer was heated in a DSC from room temperature to 200° C. at a rate of 10° C. / min under a nitrogen stream.

[0066] The melting temperature and the heat of fusion were determined from the DSC curve obtained. Specifically, the temperature at the point where the endothermic peak with the greatest maximum intensity rose in the DSC curve was taken as the melting temperature, and the area of ​​the peak was converted per gram of the evaluated sample to be the heat of fusion.

[0067] The point where the peak rises means the intersection point between the baseline and the tangent line at the inflection point. (3) Melt Mass Flow Rate The melt mass flow rate of the resin component contained in the insulating layer was measured at a temperature of 190°C and a test load of 2.16 kg using a melt indexer (melt flow rate measuring device) manufactured by Toyo Seiki Seisakusho Co., Ltd. Note that the test specimen used was an insulating layer peeled off from an insulated wire in the same manner as in the case of the melting temperature, etc. The evaluation results are shown in the "MFR (g / 10 min)" column in Table 2. (4) Specific gravity Based on JIS K 7112 (1999), the specific gravity (density) of the resin components used in producing the insulating layer was measured by the underwater displacement method. (5) Haze value, haze evaluation The haze value was evaluated based on the standard ISO 6542. Specifically, a glass plate for measuring the haze value was prepared using a haze test device shown in FIG.

[0068] The haze test device has a structure in which a beaker 31 with an inner diameter of φ83 mm and a height of 190 mm, a silicon packing 32, a glass plate 33 of 100 mm×100 mm, filter paper 34, and a cooling plate 35 are laminated.

[0069] An oil bath was filled with silicone oil to a height of 130 mm and heated to 100°C.

[0070] Next, the insulated wire 10 to be evaluated was placed in the beaker 31 of the haze test device, and the packing 32, glass plate 33, filter paper 34, and cooling plate 35 were stacked at the upper opening of the beaker 31, and the beaker was covered with a lid. Three insulated wires of the same sample were prepared with lengths of 230 mm, 225 mm, and 220 mm. The three insulated wires were arranged in a circular shape at the bottom of the beaker 31 without overlapping. The cooling plate 35 was configured so that water at 21°C flowed inside to cool the glass plate 33 and the like.

[0071] The haze test device was then placed in an oil bath and heated for 16 hours.

[0072] Next, the haze test device was removed from the oil bath and left to stand for one hour in an air atmosphere, specifically, in an environment with a temperature of 23° C. and a relative humidity of 50% RH.

[0073] Then, the glass plate was removed, and the haze was measured using a haze measuring device (manufactured by Murakami Color Research Laboratory, model: Haze Meter HM-150L2).

[0074] For the same sample of the same experimental example, heating by the above-mentioned haze test device and measurement of the haze on the glass plate were carried out twice under the same conditions, and the average value of the two measurement results was taken as the haze value for that experimental example.

[0075] When the obtained haze value was 15% or less, the haze was rated as A, and when it was more than 15%, the haze was rated as B. When the haze was rated as A, it meant that the insulated wire was capable of suppressing the occurrence of clouding on the surrounding light-transmitting member even when heated.

[0076] The insulated wires in the respective experimental examples will be described below.

[0077] In the following experimental examples, insulated wires were produced according to experimental examples 1 to 8. Experimental examples 1 to 4 are working examples, and experimental examples 5 to 8 are comparative examples. [Experimental Example 1] In Experimental Example 1, an insulated wire was produced that had a conductor 11 and an insulating layer 12 covering the outer surface of the conductor 11, as shown in FIG.

[0078] Specifically, the components were mixed in the hopper of an extruder at the blending ratio (mass ratio) shown in Table 1, and extrusion was performed by setting the temperature of the extruder to 180°C. In all of Experimental Examples 1 to 8, the resin component contained 100% polyethylene by mass. The extrusion was performed by extrusion coating an insulating layer on a conductor with an outer diameter of 0.75 mm. After the extrusion, a crosslinking treatment was performed using an electron beam. A single wire of tin-plated soft copper was used as the conductor, and the outer diameter of the obtained insulated wire was 1.4 mm.

[0079] The insulated wire thus obtained was subjected to the above-mentioned evaluations, and the evaluation results are shown in Table 2. [Experimental Examples 2 to 8] An insulated wire was produced and evaluated in the same manner as in Experimental Example 1, except that the blending ratio (mass ratio) of each material supplied to the extrusion molding machine was changed to the value shown in Table 1. The evaluation results are shown in Table 2.

[0080] [Table 1]

[0081] [Table 2] According to the above results, it was confirmed that the insulated wires of Experimental Examples 1 to 4, in which the resin component used in the insulating layer had a melting temperature of 110°C or less, a heat of fusion of 80 J / g or less, and contained stearic acid as a lubricant, had a haze value of 15% or less and a haze evaluation of A. That is, it was confirmed that these insulated wires were capable of suppressing the occurrence of clouding on the surrounding light-transmitting member even when heated. [Explanation of symbols]

[0082] 10 Insulated wire 11 Conductor 12, 201, 202 Insulating layer 21 Additives 22 Resin components 221 Main Chain 222 Side Chain 31 Beaker 32 Packing 33 Glass Plate 34 Filter Paper 35 Cooling plate

Claims

1. A conductor; an insulating layer covering an outer surface of the conductor; The insulating layer contains a resin component and stearic acid as a lubricant, The resin component contains polyethylene as a main component, The resin component has a melting temperature of 110° C. or lower and a heat of fusion of 80 J / g or lower.

2. 2. The insulated wire according to claim 1, wherein the insulated wire is placed in a container covered with a glass plate, heated at 100° C. for 16 hours, and then left in an air atmosphere for 1 hour, in accordance with ISO 6452. The insulated wire according to claim 1, wherein the haze value of the glass plate is 15% or less.

3. The insulated wire according to claim 1 or 2, wherein the resin component has a melt mass flow rate of more than 1.0 g / 10 min.

4. The insulated wire according to claim 1 , which is used for wiring in a headlight of an automobile.

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