Resin material, exterior body for electric wire, and wire harness with exterior body

Abstract

To provide a resin material that can delay the spread of fire, and an exterior body for wires and a wire harness with an exterior body, each including the resin material.SOLUTION: A resin material includes a substrate composed of a resin with a density of 200 kg / m3 or more and 1000 kg / m3 or less, and particulate colorants dispersed on at least the surface of the substrate, the colorant being a carbon material. As measured on the surface of the substrate, the brightness (L* value) in CIE-L*a*b* color space is 40 or more and 90 or less.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a resin material, and an exterior body for electric wires and a wire harness with an exterior body using the same. [Background technology]

[0002] An electric wire exterior body is used around a wire harness arranged in a vehicle, etc., in order to protect the wire harness from external forces. It is undesirable for such an electric wire exterior body to be deformed by the weight or vibration of the wire harness or to expose the internal object to be protected, and therefore it is desirable for the electric wire exterior body to have an appropriate strength.

[0003] As an example of an electric wire exterior body for protecting such a wire harness, Patent Document 1 describes an electric wire exterior body formed by folding a thermoplastic resin foam sheet and attached to the outer periphery of an electric wire. This electric wire exterior body includes a plurality of wall portions that extend along the extension direction of the electric wire and form a housing portion that houses the electric wire, and these multiple wall portions have an outer cover wall portion, an inner cover wall portion that overlaps and is joined to the outer cover wall portion, and side wall portions adjacent to both ends of the inner cover wall portion, and are configured to support the inner cover wall portion with the side wall portions at both ends. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-13107 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, from the viewpoint of improving fuel efficiency of vehicles, weight reduction is required for electrical systems such as wire harnesses, and weight reduction is also required for wire exterior bodies that protect the electric wires that constitute the wire harnesses. In order to reduce the weight of the wire exterior body, it is considered to form the wire exterior body using a resin foam sheet, as described in Patent Document 1.

[0006] However, if the exterior body protecting the electric wires is made of resin as described in Patent Document 1, when a fire occurs in a vehicle or the like, the fire tends to spread easily to the exterior body, and the fire tends to spread quickly.

[0007] If the outer casing for electric wires is prone to fire spread, the fire may spread from the outer casing for electric wires to the wire harness, hindering proper operation of the safety device connected to the wire harness. Therefore, it is desirable to use a resin material for the outer casing for electric wires that can slow down the rate of fire spread even slightly.

[0008] As a countermeasure to retard the spread of fire in the event of a fire, for example, it is effective to construct an exterior body for electric wires from a resin containing a flame retardant.

[0009] However, since flame retardants are relatively expensive, the use of a resin material containing a flame retardant for an exterior body has the problem of increasing the wiring costs of the electric wires protected by the exterior body. In particular, when the resin used for the exterior body is a foamed resin, the surface area is larger than that of a non-foamed resin, and therefore there is a risk of the fire spreading more quickly.

[0010] The present invention provides a resin material capable of retarding the spread of fire, and an exterior body for electric wires and a wire harness with an exterior body each using the resin material. [Means for solving the problem]

[0011] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, it has been discovered that a particulate colorant made of a carbon material is present in a dispersed state on at least the surface of a resin substrate, and that the CIE-L * a * b * Lightness in color space (L * The inventors discovered that by using a resin material with a carbon content (CO2 content) adjusted to a range of 40 or more and 90 or less, even if the resin material ignites and burns, the carbon material acts as a reducing agent to weaken the flames, and the high-temperature resin melts and drips (drips), slowing the spread of the fire in the resin material, which led to the completion of the present invention.

[0012] That is, the gist of the present invention is as follows. (1) Density is 200 kg / m 3 More than 1000kg / m 3 and a particulate colorant present in a dispersed state at least on a surface of the substrate, the colorant being a carbon material, and * a * b * Lightness in color space (L * Resin material with a resin content of 40 or more and 90 or less. (2) The resin material according to (1) above, wherein the carbon material is made of carbon nanoparticles having an average particle size in the range of 10 nm to 80 nm. (3) The resin material according to (1) or (2) above, wherein the resin is a foamed resin. (4) The resin material according to (3) above, wherein the foamed resin has an expansion ratio in the range of 1.5 to 4 times. (5) The resin material according to any one of (1) to (4) above, wherein the resin contains one or both of a polypropylene resin and a polyethylene resin. (6) An outer casing for an electric wire that is attached to the outer periphery of an electric wire, An outer casing for electric wire, which is made of the resin material according to any one of (1) to (5) above. (7) A wire harness and the electric wire outer casing according to (6), The wire harness is provided with an exterior body, in which the electric wire exterior body is attached to an outer periphery of the wire harness. Effect of the Invention

[0013] According to the present invention, it is possible to provide a resin material capable of retarding the spread of fire, and an outer casing for electric wires and a wire harness with an outer casing that use the resin material. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a graph showing the relationship between the concentration [mass %] of the carbon material and the lightness (L* value) when polypropylene resin is used as the resin, with the concentration of the carbon material on the horizontal axis and the lightness on the vertical axis. [Diagram 2] FIG. 2 is a schematic perspective view showing the structure of an exterior body for an electric wire according to the present invention. [Diagram 3] FIG. 3 is a graph showing the relationship between lightness (L* value) in the CIE-L*a*b* color space and the flame spread rate [mm / min] for the resin materials of Invention Examples 1 and 2 and Comparative Examples 1 and 2, with lightness on the horizontal axis and flame spread rate on the vertical axis. [Figure 4] FIG. 4 is a graph showing the relationship between lightness (L* value) in the CIE-L*a*b* color space and the amount of molten resin dripping from the resin material [g] for the resin materials of Invention Examples 1 and 2 and Comparative Examples 1 and 2, with lightness on the horizontal axis and the amount of molten resin dripping on the vertical axis. [Diagram 5] FIG. 5 is a set of photographs showing the state of the resin material in Example 2 of the present invention and Comparative Example 1 when the fire spread rate was being measured, with FIG. 5(a) showing the state of the resin material in Example 2 of the present invention when fire was spreading, and FIG. 5(b) showing the state of the resin material in Comparative Example 1 when fire was spreading. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Preferred embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

[0016] 1.Resin material The resin material of the present invention has a density of 200 kg / m 3 More than 1000kg / m 3 The present invention is composed of a substrate made of a resin having the following properties and a particulate colorant present in a dispersed state at least on the surface of the substrate, the colorant being a carbon material, and the CIE-L * a * b * Lightness in color space (L * The value of the resin is in the range of 40 to 90. As a result, when the resin material ignites and burns, the carbon material acts as a reducing agent to weaken the fire even without the addition of a flame retardant, and the resin melts and drips from the resin material, delaying the spread of the fire. More specifically, the carbon material acts as a reducing agent and consumes oxygen in the air, thereby weakening the fire when the resin material is burned. At the same time, although the resin may be heated and burned due to the heat generated when the material burns, the resin melts and drips from the resin material, dispersing the thermal energy and lowering the temperature of the resin material, which is thought to delay the spread of the fire. Here, from the viewpoint of imparting non-combustibility to the flame-retardant material, the melt dripping of the resin from the resin material is an undesirable phenomenon, but from the viewpoint of delaying the spread of the fire of the resin material, the melt dripping of the resin from the resin material is thought to be a desirable phenomenon because it can lower the temperature of the resin material. Therefore, it is possible to provide a resin material capable of retarding the spread of fire without the inclusion of a flame retardant, and an exterior body for electric wires and a wire harness with an exterior body using the resin material.

[0017] Here, the "dispersed state" in the present invention refers to a state in which particles of a carbon material or the like, which is a dispersoid, are distributed in a resin, which is a dispersion medium. In particular, the dispersoid is not limited to carbon material particles, and may contain other particles. Furthermore, the distribution of the dispersoid in the resin is not limited to a homogeneous distribution, and may be a non-homogeneous distribution. Furthermore, the "particulate state" in the present invention includes not only a state in which a particle exists alone, but also a state in which multiple particles are aggregated.

[0018] (base material) The resin base material has a density of 200 kg / m 3 More than 1000kg / m 3 The resin is made of a resin having a density of 1000 kg / m or less. This reduces the weight of the resin material, so that when the resin material is used for the electric wire sheath, the electric wire sheath and the wire harness with the sheath can be made lighter. From this viewpoint, the density of the resin is 1000 kg / m or less. 3 It is preferable that the thickness is less than 700 kg / m 3 More preferably, it is 500 kg / m or less. 3 It is more preferable that the density of the resin is 200 kg / m or less from the viewpoint of ensuring the mechanical strength of the resin material. 3 It may be more than that.

[0019] Here, the resin constituting the base material is preferably a foamed resin. This allows the weight of the resin base material to be reduced, and the wire harness to be protected from deformation due to weight, vibration, etc. Here, even if the resin material of the present invention uses foamed resin, which has a large surface area and is easily heated, as the base material, the carbon material acts as a reducing agent, and the foamed resin melts and drips from the resin material, dispersing thermal energy, thereby delaying the spread of fire in the resin material.

[0020] In particular, when the resin constituting the base material is a foamed resin, the foaming ratio of the foamed resin is preferably in the range of 1.5 to 4 times, more preferably in the range of 2 to 3 times. By setting the foaming ratio of the foamed resin within this range, the buffering effect against mechanical shock is enhanced while maintaining the mechanical strength required for the electric wire sheath, so that when the resin material is used for the electric wire sheath, the wire harness can be protected from deformation due to weight, vibration, etc. Here, the "foaming ratio" can be expressed as the ratio of the volume of the foamed resin to the volume of an unfoamed resin composition made of the same material as the foamed resin and having the same mass.

[0021] The resin is not particularly limited as long as it is flammable and melts when heated. The resin may be composed of either a thermoplastic resin or a thermosetting resin. More specifically, the resin may be one or more of polypropylene, polyethylene, polyvinyl chloride, polystyrene, AS resin, ABS resin, polyethylene terephthalate, methacrylic resin, polyvinyl alcohol, vinylidene chloride resin, polycarbonate, polyamide, polyimide, acetal resin, polybutylene terephthalate, fluorine resin, phenol resin, melamine resin, urea resin, polyurethane, epoxy resin, unsaturated polyester resin, etc. Among them, it is preferable that the resin contains one or both of polypropylene resin and polyethylene resin.

[0022] Various additives that are added to ordinary resins may be added to the resin depending on the application. The additives may be, for example, one or more of fillers, antioxidants, stabilizers, metal deactivators, ultraviolet absorbers, light stabilizers, plasticizers, nucleating agents, compatibilizers, clarifiers, antistatic agents, lubricants, etc., without any particular limitation. Here, the resin material of the present invention can retard the spread of fire in the resin material without containing a flame retardant, which is expensive in material cost.

[0023] (Coloring material) A carbon material, which is a particulate coloring material, is present in a dispersed state at least on the surface of the resin material. In the present invention, the carbon material present at least on the surface of the substrate as a coloring material also acts as a fire retardant. As a result, when the resin material ignites and burns, the carbon material dispersed at least on the surface of the substrate acts as a reducing agent and takes in oxygen from the air, thereby weakening the flames when the resin material burns and retarding the spread of the fire.

[0024] Here, the substrate containing the carbon material as a coloring material has a CIE-L * a * b * Lightness in color space (L * The value of the lightness (L *By making the lightness (L value) 40 or more, and preferably 50 or more, the carbon material dispersed in the base material can act as a reducing agent, and as a result, the spread of fire in the resin material can be delayed. * By setting the carbonization ratio (value) to 90 or less, and preferably 80 or less, carbonization of the resin material due to excessive inclusion of carbon material is made less likely to occur, and thus concentration of thermal energy due to combustion of the carbonized portion is made less likely to occur.

[0025] In addition, the carbon material as the coloring material is preferably made of carbon nanoparticles with an average particle size in the range of 10 nm to 80 nm, which allows the carbon material to be stably dispersed in the resin, so that even if the resin melts due to combustion of the resin material, the carbon material can act as a reducing agent.

[0026] The resin material of the present invention may contain a coloring material other than the carbon material. That is, the resin material may have a color colored by a coloring material other than the carbon material in addition to an achromatic color such as white, gray, or black colored by the carbon material.

[0027] The CIE-L * a * b * Lightness in color space (L * The value) is preferably greater than 80, and more preferably greater than 90. This makes it easier to enhance the fire retardant effect of the carbon material dispersed at least on the surface of the substrate.

[0028] As an example, when polypropylene is used as the resin, the CIE-L * a * b * Lightness in color space (L * The measured value is 92.4. At this time, the concentration of the carbon material [mass%] and the CIE-L * a * b * Lightness in color space (L* The relationship between the lightness (L value) and the resin surface is shown in Figure 1. * Considering the case where a material with low lightness (L * Instead of the carbon content (value), the concentration of the carbon material contained in the resin material may be specified. In this case, the concentration of the carbon material contained in the resin material may be in the range of 0.2 mass % to 5.0 mass % with respect to the total mass of the resin material.

[0029] (Properties of resin materials, etc.) The resin material of the present invention preferably has a low fire spread rate when ignited. More specifically, the resin material of the present invention preferably has a fire spread rate of 80 mm / min or less, more preferably 70 mm / min or less when ignited. In the resin material of the present invention, the carbon material acts as a reducing agent to weaken the fire, and the high-temperature resin melts and flows down, so that the spread of the fire in the resin material and the spread of the fire from the resin material to the surroundings can be delayed. As a result, it is possible to easily obtain a time grace period to notify the outside of the fire, activate safety devices such as fire hydrants and sprinklers, or evacuate people in the vicinity of the flames. Here, the flame spread rate of a resin material can be determined by measuring the time required for the fire to spread from one marked line to the other marked line when a test piece of a rectangular resin material 125 mm long, 13 mm wide, and 1.5 mm thick has a marked line along the width, 25 mm from each end of the length, and is placed horizontally and exposed to a flame from one end of the length. The flame spread rate can be determined from the measured time and the length between the marked lines (75 mm).

[0030] The lower limit of the thickness of the resin material of the present invention is preferably 0.5 mm, more preferably 1.0 mm. Here, by making the thickness of the resin material 0.5 mm or more, the fire spread speed can be slowed down. On the other hand, the upper limit of the thickness of the resin material is not particularly limited, but is preferably 5.0 mm, for example, and more preferably 3.0 mm. Here, by making the thickness of the resin material 5.0 mm or less, the resin material can be made lighter.

[0031] 2.Exterior body for electric wires The resin material of the present invention is an electric wire sheathing that is attached to the outer periphery of an electric wire, and is made of the above-mentioned resin material.

[0032] The following will be described in detail with reference to the drawings. FIG. 2 is a schematic perspective view showing the structure of an electric wire exterior body according to the present invention. The electric wire exterior body 10 of the present invention has a wall portion 3 existing along the extending direction X of the electric wire 2, and has a housing portion 11 formed by being surrounded by this wall portion 3 and housing the electric wire 2. Since the electric wire exterior body 10 is made of the above-mentioned resin material, even if a flame in a fire or the like ignites the resin material, the spread of the fire in the resin material is delayed, and the ignition of the electric wire 2 is also delayed. Therefore, the fire can be notified to the outside by communication using the electric wire 2, or a safety device such as a fire hydrant or a sprinkler can be activated. In addition, it is possible to give people in the vicinity of a fire more time to evacuate. In FIG. 2, the electric wire 2 is shown as a single cylindrical shape, but the electric wire 2 may be a bundle of electric wires in which two or more electric wires are bundled together, such as a wire harness, or may be branched as necessary.

[0033] The shape of the electric wire outer casing 10 is not particularly limited, and for example, as shown in Fig. 2, the wall portion 3 may be formed by folding one sheet of resin material at multiple folding portions 3a to 3d. In this case, it is preferable that the wall portion 3 of the electric wire outer casing 10 is configured to surround the entire circumference of the electric wire 2. This makes it possible to easily obtain a time grace period for activating a safety device, since the spread of fire beyond the electric wire outer casing 10 is delayed even if the electric wire outer casing 10 catches fire.

[0034] 3. Wire harness with exterior body The wire harness 1 with an exterior body of the present invention includes a wire harness 20 constituted by electric wires 2 and the above-mentioned electric wire exterior body 10, and the electric wire exterior body 10 is attached to the outer periphery of the wire harness 20. As a result, at least a part of the electric wire bundle constituting the wire harness 20 and the electric wire assembly constituted by a plurality of divided electric wire bundles branching out and extending from the electric wire bundle are protected by the resin material, so that even if the electric wire exterior body 10 catches fire, it is possible to easily obtain a time grace period until the fire spreads to the wire harness 20 and the operation of the wire harness 20 stops. EXAMPLES

[0035] Next, in order to further clarify the effects of the present invention, examples of the present invention and comparative examples will be described, but the present invention is not limited to these examples.

[0036] [Inventive Examples 1 and 2, Comparative Examples 1 and 2] (Preparation of resin material) Polypropylene resin (Japan Polypropylene Corporation, product name: EA9, density: 900 kg / m 3 The substrate was mixed with carbon nanoparticles (manufactured by Asahi Carbon Co., Ltd., product name: Asahi #70, average particle size: 28 nm) as a carbon material (colorant) and an antioxidant (pentaerythritol tetrakis (3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), manufactured by BASF, product name: Irganox 1010) as an additive. The amount of the antioxidant added was 0.5 parts by mass per 100 parts by mass of the substrate.

[0037] The obtained compound was melt-kneaded and foamed so that the volume after foaming was 2.0 times that before foaming, to obtain a homogeneous resin composition.

[0038] The obtained resin composition was extrusion molded to obtain a film-like resin material having a thickness of 1.5 mm.

[0039] At this time, by changing the amount of carbon nanoparticles contained in the resin, four types of resin materials were obtained (Invention Examples 1 and 2, Comparative Examples 1 and 2). * a * b * Lightness in color space (L * The measured values ​​of the carbon nanoparticles (values) were 24.7 (Comparative Example 1), 43.5 (Invention Example 1), 79.9 (Invention Example 2), and 92.4 (Comparative Example 2), respectively. Note that Comparative Example 1 is an example in which the resin contains an excess of carbon nanoparticles, and is outside the scope of the present invention. Furthermore, Comparative Example 2 is an example in which the resin does not contain carbon nanoparticles, and is outside the scope of the present invention.

[0040] The density of the resulting film-like resin material [kg / m 3 The expansion ratio of each of the obtained film-like resin materials was 1.9 times as shown in Table 1.

[0041] The resin material was cut into a rectangle of 125 mm in length, 13 mm in width, and 1.5 mm in thickness, and a test piece was prepared by marking the width at 25 mm from each end in the length direction. The test piece was held horizontally and a flame was applied from one end in the length direction. The time required for the flame to spread from one mark to the other was measured, and the flame spread rate [mm / min] of the resin material was calculated from the measured time and the length between the marks (75 mm). The number of times that the molten resin dripped from the resin material during the flame spread from one mark to the other was visually counted, and the amount of the molten resin that dripped during the flame spread was weighed. The results are shown in Table 1.

[0042] Furthermore, for the resin materials of Examples 1 and 2 of the present invention and Comparative Examples 1 and 2, CIE-L * a * b * Lightness in color space (L * A graph showing the relationship between the brightness (value) and the flame spread rate [mm / min] is shown in Figure 3. The graph in Figure 3 plots brightness on the horizontal axis and flame spread rate on the vertical axis.

[0043] In addition, the resin materials of Examples 1 and 2 of the present invention and Comparative Examples 1 and 2 were * a * b * Lightness in color space (L * A graph showing the relationship between the lightness (value) and the amount of molten resin dripping from the resin material [g] is shown in Figure 4. The graph in Figure 4 plots the lightness on the horizontal axis and the amount of molten resin dripping on the vertical axis.

[0044] [Table 1]

[0045] From the evaluation results in Table 1, the CIE-L * a * b * Lightness in color space (L * It was confirmed that the resin materials of Inventive Examples 1 and 2, in which the flame spread rate (value) was within the appropriate range of the present invention, had a flame spread rate of 70 mm / min or less. Furthermore, in the resin materials of Inventive Examples 1 and 2, the resin melted and dripped when the fire spread, and no char was observed after combustion, as shown in Figure 5(a).

[0046] In contrast, in Comparative Example 1, the lightness (L * When the value) was smaller than the appropriate range of the present invention, the flame spread rate exceeded 70 mm / min, and did not meet the pass level. Here, from the graph in FIG. 4, it was found that the amount of molten resin dripping from the resin material in Comparative Example 1 was less than in Invention Examples 1 and 2. Furthermore, as shown in FIG. 5(b), the resin material in Comparative Example 1 had charred resin material remaining after combustion. From these facts, it was found that the brightness (L * Since the carbon content was high and the thermal expansion coefficient was small, energy was concentrated in the carbonized resin, which accelerated the combustion, and there was almost no molten resin dripping, which is thought to have increased the speed of fire spread.

[0047] In Comparative Example 2, the carbon material was not included, and the lightness (L *When the lightness (L value) was larger than the appropriate range of the present invention, the flame spread rate exceeded 70 mm / min, and the pass level was not met. * It is believed that the fire spread rate increased without any decrease in the fire spread rate due to the carbon material being absent, because the heat resistance (Hv) was large and the material did not contain any carbon material.

[0048] From the above results, it was confirmed that the resin materials of Inventive Examples 1 and 2 were able to effectively retard the spread of fire even without blending a flame retardant.

[0049] In addition, the resin materials of the invention examples 1 and 2 have a density of 200 kg / m 3 More than 1000kg / m 3 It was also confirmed that it is lightweight since it is within the following range. [Explanation of symbols]

[0050] 1. Wire harness with outer casing 10. Cable sheathing 11 Storage section 2 electric wire 20 Wire Harness 3 wall 3a~3d bending part X Wire extension direction

Claims

1. The present invention includes a wire harness including electric wires, and an outer casing for electric wires attached to an outer periphery of the wire harness, The electric wire exterior body is made of a resin material, The resin material is Contains one or both of polypropylene resin and polyethylene resin and has a density of 200 kg / m ３ More than 1000kg / m ３ A substrate made of the following resin: A particulate colorant present in a dispersed state at least on the surface of the base material; It is composed of the coloring material is a carbon material, CIE-L measured on the surface of the resin material ＊ a ＊ b ＊ Lightness in color space (L ＊ The wire harness with an exterior body, wherein the resistance (R) of the wire harness is in the range of 40 or more and 90 or less.

2. 2. The wire harness with an exterior according to claim 1, wherein the carbon material contained in the resin material is made of carbon nanoparticles having an average particle size in the range of 10 nm to 80 nm.

3. The wire harness with an exterior body according to claim 1 or 2, wherein the resin constituting the base material is a foamed resin.

4. The wire harness with an exterior body according to claim 3 , wherein the foamed resin has an expansion ratio in the range of 1.5 times or more and 4 times or less.

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