Wiring harness and resin composition

Abstract

The present invention provides a wiring harness and a resin composition. Even when the insulator materials of the cable group and the sheath are different, the wiring harness suppresses water from infiltrating from the branch portion by using a resin molded article that covers the branch portion of the cable group. There is provided a wiring harness (1) including: a multi-core cable (2) having an ABS sensor cable (21) with an outermost layer made of thermoplastic polyurethane and an electric parking brake cable (22) with an outermost layer made of polyolefin, and a sheath (23) made of thermoplastic polyurethane provided around them; and a resin molded article (3) that covers the sheath (23), the ABS sensor cable (21), and the electric parking brake cable (22) at a cable branch portion (4), the resin molded article (3) being composed of a polymer alloy of a first polymer containing at least one of a polyamide-based polymer, a polyester-based polymer, and thermoplastic polyurethane and a second polymer containing polyolefin.

Description

Technical Field

[0001] The present invention relates to a wire harness and a resin composition. Background Art

[0002] Conventionally, a composite wire harness in which an ABS sensor cable and a parking brake cable are housed in a sheath has been known. In this composite wire harness, a bifurcated portion where the ABS sensor cable and the parking brake cable branch out from the end of the sheath is covered with a molded portion made of polyurethane (see Patent Document 1).

[0003] According to Patent Document 1, at the above-described bifurcated portion, the end of the sheath, the ABS sensor cable, and the parking brake cable are covered with the molded portion, and thus ingress of water from the end of the sheath to the inside is suppressed.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-91731 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] However, in the composite wire harness described in Patent Document 1, in order to sufficiently suppress ingress of water from the end of the sheath, it is necessary for the sheath, the ABS sensor cable, and the parking brake cable to all have high adhesiveness to the molded portion.

[0009] Generally, polyolefins such as crosslinked polyethylene, which have low adhesiveness to polyurethane, are often used in the insulators of the ABS sensor cable and the parking brake cable. Patent Document 1 does not disclose the insulator materials of the ABS sensor cable and the parking brake cable, but in the case of using polyolefins, adhesiveness to the molded portion cannot be ensured, and there is a possibility that water may ingress from the end of the sheath to the inside.

[0010] Therefore, an object of the present invention is to provide a wire harness that suppresses ingress of water from a bifurcated portion by a resin molded article covering the bifurcated portion of a cable group even when the insulator material of the cable group is different from the insulator material of the sheath.

[0011] Means for Solving the Problems

[0012] For the purpose of solving the above problems, the present invention provides a wire harness, comprising: a multi-core cable having a cable group composed of a plurality of cables and a sheath provided around the cable group, and a resin molded part covering the sheath and the cable group at a cable bifurcation part where the cables bifurcate from an end of the sheath of the multi-core cable; the outermost layer of each cable constituting the cable group is made of polyolefin or thermoplastic polyurethane; when the sheath is made of polyolefin, the cable group includes at least one cable having an outermost layer made of thermoplastic polyurethane; when the sheath is made of thermoplastic polyurethane, the cable group includes at least one cable having an outermost layer made of polyolefin; the resin molded part is composed of a polymer alloy of a first polymer containing at least one of a polyamide-based polymer, a polyester-based polymer, and thermoplastic polyurethane and a second polymer containing polyolefin.

[0013] Advantages of the Invention

[0014] According to the present invention, a wire harness can be provided, which suppresses water from infiltrating from the bifurcation part by using a resin molded part covering the bifurcation part of the cable group even when the insulator materials of the cable group and the sheath are different. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view of the periphery of the cable bifurcation part of the wire harness according to an embodiment of the present invention.

[0016] Figure 2 It is a side view of the periphery of the bifurcation part of the wire harness according to an embodiment of the present invention.

[0017] Figure 3 It is a radial cross-sectional view of the multi-core cable according to an embodiment of the present invention.

[0018] Figure 4 (a)-(c) are SEM (scanning electron microscope) observation images of the phase structure of the polymer alloy of the first polymer and the second polymer.

[0019] Figure 5 (a) is a cross-sectional view of a main part of a specimen used in the airtightness evaluation test according to an embodiment of the present invention, magnified. Figure 5 (b) is a schematic diagram showing the implementation state of the airtightness test according to an embodiment of the present invention.

[0020] Description of Reference Numerals

[0021] 1: Wire harness; 2: Multi-core cable; 21: ABS sensor cable; 213: Sheath; 22: Electric parking brake cable; 222: Insulator; 23: Sheath; 3: Resin molded part; 4: Cable bifurcation part. DETAILED DESCRIPTION OF THE INVENTION

[0022] 〔Embodiment〕

[0023] Figure 1 This is a perspective view of the periphery of the cable bifurcation portion 4 of the wiring harness 1 according to an embodiment of the present invention.

[0024] The wiring harness 1 is an automotive component for wiring in the driver's cab of an automobile, and includes: a multi-core cable 2 in which an ABS (antilock braking system) sensor cable 21 and an electric parking brake (EPB) cable 22 are covered by a sheath 23; and a resin molded part 3 that covers the sheath 23, the ABS sensor cable 21, and the electric parking brake cable 22 at the cable bifurcation portion 4 where the ABS sensor cable 21 and the electric parking brake cable 22 branch out from the end of the sheath 23 of the multi-core cable 2 and inhibits water from seeping into the multi-core cable 2 from the end of the sheath 23.

[0025] The ABS sensor cable 21 is a cable used in the antilock braking system of an automobile and is a signal line responsible for signal transmission between a wheel speed sensor that detects the rotational speed of a wheel and an electronic control unit on the vehicle body side. A connector for connecting to the wheel speed sensor, for example, is provided at the front end of the cable bifurcation portion 4 of the ABS sensor cable 21.

[0026] The electric parking brake cable 22 is a cable used in the EPB system of an automobile and is a power supply line that electrically connects an electric motor built in a brake caliper constituting a disc brake in the driver's cab to a brake control unit on the vehicle body side and supplies power for driving the brake caliper. A connector for connecting to the electric motor built in the brake caliper, for example, is provided at the front end of the cable bifurcation portion 4 of the electric parking brake cable 22.

[0027] Figure 2 This is a side view of the periphery of the cable bifurcation portion 4 of the wiring harness 1. At the end of the multi-core cable 2 where the sheath 23 has been removed, the exposed ABS sensor cable 21 and the electric parking brake cable 22 branch out, and this bifurcation portion is fixed by the resin molded part 3 to maintain the branched state.

[0028] Figure 1 , Figure 2 In the example shown, the electric parking brake cable 22 extends along the length direction of the multi-core cable 2 starting from the cable bifurcation portion 4, and the ABS sensor cable 21 extends in a manner deviating from the length direction of the multi-core cable 2 starting from the cable bifurcation portion 4. However, the directions in which the ABS sensor cable 21 and the electric parking brake cable 22 extend from the cable bifurcation portion 4 (the branched state) are not particularly limited.

[0029] Figure 3It is a radial cross-sectional view of the composite cable 2. In the multi-core cable 2, a sheath 23 is provided around the ABS sensor cable 21 and the two electric parking brake cables 22. In order to stabilize the configuration of the ABS sensor cable 21 and the electric parking brake cable 22, an interlayer 24 can be provided in the gap between the ABS sensor cable 21 and the electric parking brake cable 22. In addition, a compression tape can also be wound around the ABS sensor cable 21 and the electric parking brake cable 22.

[0030] The sheath 23 is made of thermoplastic polyurethane (TPU). In addition, a flame retardant for improving flame retardancy can be contained in the material of the sheath 23. In addition, crosslinking can also be introduced to improve heat resistance.

[0031] The ABS sensor cable 21 includes two ABS cables 210 and a sheath 213 made of thermoplastic polyurethane provided around them. Crosslinking can be introduced into the material of the sheath 213. The ABS cable 210 includes a linear conductor 211 and an insulator 212 provided around the conductor 211. The conductor 211 is made of a conductive material such as copper, and the insulator 212 is made of an insulating material such as crosslinked polyethylene or crosslinked ethylene-vinyl acetate copolymer. A flame retardant can be contained in the material of the insulator 212.

[0032] The electric parking brake cable 22 includes a linear conductor 221 and an insulator 222 provided around the conductor 221. The conductor 221 is made of a conductive material such as copper, and the insulator 222 is made of polyolefin. As the polyolefin that becomes the material of the insulator 222, for example, polyethylene, crosslinked polyethylene, polypropylene, crosslinked ethylene-propylene rubber, crosslinked ethylene-vinyl acetate copolymer, ethylene ethyl acrylate polymer, etc. can be used. In particular, crosslinked polyethylene or crosslinked ethylene-vinyl acetate copolymer is preferred because of its low price and excellent end processability. A flame retardant can also be contained in the material of the insulator 222.

[0033] In addition, the polyolefin as the material of the insulator 222 can also be an acid-modified polyolefin. As the acid of the acid-modified polyolefin, unsaturated carboxylic acids and their derivatives can be used. More specifically, maleic anhydride can be appropriately used.

[0034] The resin molded part 3 is composed of a polymer alloy of a first polymer containing at least one of a polyamide-based polymer, a polyester-based polymer, and a thermoplastic polyurethane and a second polymer containing a polyolefin. The polymer alloy can be manufactured using an intermittent kneader such as a kneader or a Banbury mixer, a continuous kneader such as a twin-screw extruder, etc.

[0035] Among the polyamide-based polymers used as the first polymer, for example, polyamides such as polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 46, polyamide 610, polyamide 612, polyamide 6T, polyamide 6I, polyamide 9T, polyamide 10T, polyamide elastomers composed of copolymers of polyamide and polyether, polyether ester, etc., or substances obtained by mixing or copolymerizing them can be used.

[0036] Among the polyester-based polymers used as the first polymer, for example, polyester-based resins such as PBT (polybutylene terephthalate), polyester-based elastomers such as copolymers of PBT and polyether, and copolymers of PBT and polyester can be used.

[0037] From the viewpoint of water resistance, among the thermoplastic polyurethanes used as the first polymer, ether-based thermoplastic polyurethanes are preferably used.

[0038] Among the polyolefins used as the second polymer, the polyolefins (including acid-modified polyolefins) listed above as the materials for the insulator 222 can be used. It should be noted that in order to improve the compatibility with the first polymer, the second polymer is preferably an acid-modified polyolefin.

[0039] Since the resin molded article 3 contains the first polymer including at least one of a polyamide-based polymer, a polyester-based polymer, and a thermoplastic polyurethane, it has high adhesiveness to the sheath 23 of the multi-core cable 2 and the sheath 213 of the ABS sensor cable 21 made of thermoplastic polyurethane. In addition, since the resin molded article 3 contains the second polymer including polyolefin, it has high adhesiveness to the insulator 222 made of polyolefin which is the outermost member of the electric parking brake cable 22.

[0040] The resin molded article 3 is closely adhered to the sheath 23 of the multi-core cable 2, the sheath 213 of the ABS sensor cable 21, and the insulator 222 of the electric parking brake cable 22 by thermal bonding (heat fusion). Thus, water infiltration from the cable bifurcation portion 4 into the multi-core cable 2 can be suppressed. In this way, in the wire harness 1, the resin molded article 3 can be used to ensure the waterproofness of the cable bifurcation portion 4. Therefore, it is not necessary to additionally use a sealing member such as a heat shrinkable tube, and the number of manufacturing processes can be reduced, and the manufacturing cost can be further reduced.

[0041] With respect to a total of 100 parts by mass of the first polymer and the second polymer, the polymer alloy used as the material of the resin molded article 3 preferably contains 30 to 80 parts by mass of the first polymer and 70 to 20 parts by mass of the second polymer. By setting the content of the first polymer to 30 parts by mass or more, the adhesiveness to the sheath 23 of the multi-core cable 2 made of thermoplastic polyurethane and the sheath 213 of the ABS sensor cable 21 can be improved. On the other hand, by setting the content of the second polymer to 20 parts by mass or more, the adhesiveness to the insulator 222 of the electric parking brake cable 22 made of polyolefin can be made higher.

[0042] The phase structure of the polymer alloy constituting the resin molded article 3 may be a phase structure composed of a continuous phase and a dispersed phase, or a co-continuous structure. In addition, when it is a phase structure composed of a continuous phase and a dispersed phase, either the first polymer or the second polymer can be the continuous phase. Generally, the difference in this phase structure basically does not affect the adhesiveness of the resin molded article 3 to the sheath 23 of the multi-core cable 2, the sheath 213 of the ABS sensor cable 21, and the insulator 222 of the electric parking brake cable 22.

[0043] However, it has been confirmed that in order to make the adhesiveness of the resin molded article 3 to the electric parking brake cable 22 whose outermost layer is made of polyolefin higher, when a polyamide-based polymer is used as the first polymer constituting the polymer alloy used as the material of the resin molded article 3, when one of the first polymer and the second polymer forms a dispersed phase, the average dispersion diameter is preferably less than 125 μm, more preferably 95 μm or less. In addition, it has also been confirmed that when a polyester-based polymer is used as the first polymer constituting the polymer alloy used as the material of the resin molded article 3, when one of the first polymer and the second polymer forms a dispersed phase, the average dispersion diameter is preferably less than 125 μm, more preferably 98 μm or less. In addition, it has also been confirmed that when thermoplastic polyurethane is used as the first polymer constituting the polymer alloy used as the material of the resin molded article 3, when one of the first polymer and the second polymer forms a dispersed phase, the average dispersion diameter is preferably less than 120 μm, more preferably 100 μm or less. Therefore, it can be said that when one of the first polymer and the second polymer forms a dispersed phase, the average dispersion diameter is preferably less than 120 μm, more preferably 95 μm or less.

[0044] Figure 4 (a) is an SEM (scanning electron microscope) observation image of the phase structure of a polymer alloy in which thermoplastic polyurethane as the first polymer forms a continuous phase and acid-modified polyolefin as the second polymer forms a dispersed phase. Figure 4 (b) is an SEM observation image of the phase structure of a polymer alloy in which thermoplastic polyurethane as the first polymer and acid-modified polyolefin as the second polymer form a co-continuous structure. Figure 4(c) is a SEM observation image of the phase structure of a polymer alloy in which an acid-modified polyolefin as the second polymer forms a continuous phase and a thermoplastic polyurethane as the first polymer forms a dispersed phase.

[0045] Regarding the average dispersion diameter, for example, it can be obtained in the SEM observation images of the phase structure of polymer alloys such as Figure 4 (a) to (c) in such a way that the particle sizes (if they are elliptical, for example, the average of the major axis and the minor axis) of any number of dispersed particles within any observation range are averaged. For changing (decreasing) the average dispersion diameter, it is effective to increase the shear rate during the kneading of the polymer alloy. For example, methods such as increasing the rotational speed of the screw of an extruder, the rotor of a kneader, etc. can be adopted.

[0046] It should be noted that in the multi-core cable 2, two ABS cables 210 (the sheath 23 and the interlayer 24 in the ABS sensor cable 21 are omitted) can be used instead of the ABS sensor cable 21. In this case, the resin molded part 3 directly covers the insulator 212 of the ABS cable 210. In addition, in this case, in order to ensure high adhesiveness with the resin molded part 3, the insulator 212 is made of polyolefin. The polyolefin used in the material of the insulator 212 can be the polyolefin (including acid-modified polyolefin) listed above as the material used for the insulator 222.

[0047] In addition, the cables constituting the cable group included in the multi-core cable 2 are not limited to the ABS sensor cable 21 and the electric parking brake cable 22, as long as they are cables whose outermost layer is made of polyolefin or thermoplastic polyurethane in the same way as the ABS sensor cable 21 and the electric parking brake cable 22. They can also be other cables, and in addition, the number of them is not limited. In addition, the material of the sheath 23 of the multi-core cable 2 can also be polyolefin.

[0048] That is, the outermost layer of each cable constituting the cable group included in the multi-core cable 2 is made of polyolefin or thermoplastic polyurethane. When the sheath 23 of the multi-core cable 2 is made of polyolefin, the cable group includes at least one cable having an outermost layer made of thermoplastic polyurethane, and the outermost layer of the other cables is made of thermoplastic polyurethane. In addition, when the sheath 23 of the multi-core cable 2 is made of thermoplastic polyurethane, the cable group includes at least one cable having an outermost layer made of polyolefin, and the outermost layer of the other cables is made of thermoplastic polyurethane.

[0049] The radial cross-sectional shape of the multi-core cable 2 is typically Figure 3 circular as shown, but there is no particular limitation. In addition, the resin molded part 3 can be integrally formed with a grommet for soft-mounting the wire harness 1 to the vehicle body, or the resin molded part itself can form a grommet.

[0050] (Effects of the Embodiment)

[0051] According to the wire harness 1 related to the above-described embodiment, since a polymer alloy of a first polymer containing at least one of a polyamide-based polymer, a polyester-based polymer, and a thermoplastic polyurethane and a second polymer containing a polyolefin is used as the material of the resin molded article 33, the adhesiveness between the resin molded article 3 and the sheath 23 made of thermoplastic polyurethane, the ABS sensor cable 21 having a thermoplastic polyurethane outermost layer, and the electric parking brake cable 22 having a polyolefin outermost layer can be sufficiently ensured. Therefore, water infiltration from the end of the sheath 23 at the cable bifurcation portion 4 into the multi-core cable 2 can be effectively suppressed.

[0052] Examples

[0053] Hereinafter, the test results for evaluating the waterproofness of the cable bifurcation portion 4 of the wire harness 1 related to the above-described embodiment will be described.

[0054] (Configuration of Specimen for Evaluation)

[0055] Figure 5 (a) is a cross-sectional view showing an enlarged main part of the specimen 30 used in the airtightness evaluation test according to this embodiment. The specimen 30 has a linear conductor 31, an insulator 32 covering the outer periphery of the conductor 31, and a resin molded article 33 covering one end of the insulator 32.

[0056] The conductor 31 is a stranded wire composed of 7 copper conductor wires with a diameter of 0.26 mm, and air can pass through the conductor 31 inside the insulator 32. In addition, the thickness of the insulator 32 is 0.36 mm, and the outer diameter of the insulator 32 is 1.5 mm. In addition, the resin molded article 33 has a cylindrical shape with a diameter of 6 mm and a length of 20 mm, and the insertion length of the cable 34 into the resin molded article 33 is 10 mm.

[0057] In this embodiment, as shown in Tables 1 to 3 described later, specimens 30 with specimen numbers A1 to A20, B1 to B18, and C1 to C11 having different compositions of the resin molded article 33 (types of polymers constituting the polymer alloy used as the material of the resin molded article 33) are prepared. The specimens 30 with specimen numbers A1 to A20, B1 to B18, and C1 to C11 each further include two types of specimens 30 with different materials for the insulator 32.

[0058] (Evaluation Method)

[0059] <Airtightness Evaluation>

[0060] The airtightness test and the thermal shock test are alternately repeated to evaluate how long the airtightness can be maintained.

[0061] Figure 5(b) is a schematic diagram showing the implementation state of the airtightness test related to this embodiment. As Figure 5 shown in (b), the end portion on the resin molded part 33 side of the specimen 30 penetrates into the water 37 in the water tank 36, and is connected to the air supply machine 35 at the opposite end portion.

[0062] In the airtightness test, if the air supplied from the air supply machine 35 to the resin molded part 33 side through the conductor 31 leaks out as bubbles 38 from the bonding surface between the resin molded part 33 and the insulator 32, it is determined that the airtightness is lost. If no bubbles 38 are generated, it is determined that the airtightness is maintained. Here, in one airtightness test, compressed air of 200 kPa is supplied from the air supply machine 35 for 30 seconds.

[0063] In the thermal shock test, placing the specimen 30 in the atmosphere at -40°C for 30 minutes and in the atmosphere at 120°C for 30 minutes is taken as one cycle, and 100 cycles are implemented.

[0064] That is, in this airtightness evaluation, every time 100 cycles of the thermal shock test are implemented, an airtightness test is carried out to confirm whether the airtightness is maintained. The specimen 30 with the number of thermal shock test cycles at the moment when the airtightness is lost being 2000 or more is determined as "excellent" with excellent airtightness, the specimen 30 with the number being 1000 or more and less than 2000 is determined as "usable" with airtightness at a usable level, and the specimen 30 with the number being less than 1000 is determined as "unusable" with airtightness at a non-usable level.

[0065] <Adhesion evaluation>

[0066] A laminated sheet obtained by laminating and pressing a sheet made of the material of the resin molded part 33 (longitudinal 200 mm × transverse 25 mm × thickness 1 mm) and a sheet made of the material of the insulator 32 (longitudinal 200 mm × transverse 25 mm × thickness 1 mm) is used, and a T-peel test based on JIS K6854-3 (1999) is implemented to measure the peel strength. In addition, by visual inspection, it is confirmed whether the two sheets peel at the interface or whether peeling occurs due to cohesive failure of either sheet when peeling occurs.

[0067] (Evaluation result)

[0068] In Tables 1 to 3 below, the compositions of Specimens 30 with specimen numbers A1 to A18, B1 to B18, and C1 to C11 and the results of various evaluations are shown. The "average dispersion diameter" in Tables 1 to 3 is the average particle diameter of the dispersed phase of the polymer alloy that is the material of the resin molded article 33. In addition, the "sheet adhesion evaluation (crosslinked PE)" indicates the sheet adhesion evaluation when the insulator 32 is made of crosslinked polyethylene as a polyolefin, and the "sheet adhesion evaluation (TPU)" indicates the sheet adhesion evaluation when the insulator 32 is made of thermoplastic polyurethane. In addition, for the "peel pattern", "α" indicates interfacial peeling and "β" indicates cohesive failure.

[0069] In Table 1 below, the compositions of Specimens 30 with specimen numbers A1 to A18 and the results of various evaluations are shown. In Specimens 30 with specimen numbers A1 to A18, as the first polymer constituting the polymer alloy that is the material of the resin molded article 33, PA612 (Zytel 151L NC010 manufactured by DuPont) and a PA elastomer (Pebax 5533 manufactured by Arkema), which are polyamide-based polymers, were used. In addition, as the second polymer, maleic anhydride-modified ethylene-propylene rubber (Admer XE070 manufactured by Mitsui Chemicals) (described as acid-modified polyolefin in Table 1), which is a polyolefin, was used.

[0070] [Table 1]

[0071]

[0072] According to Table 1, for Specimens 30 with specimen numbers A1 and A2, when the material of the insulator 32 is thermoplastic polyurethane, the peel strength in the sheet adhesion evaluation is strong, and in addition, the airtightness evaluation is "excellent". However, when the material of the insulator 32 is crosslinked polyethylene, the peel strength in the sheet adhesion evaluation is weak, and in addition, the airtightness evaluation is "not acceptable". This is considered to be caused by the following reason: Only the first polymer was used in the material of the resin molded article 33, so although the adhesiveness to thermoplastic polyurethane is sufficient, the adhesiveness to polyolefin is insufficient.

[0073] In addition, based on the evaluation of Specimens 30 with specimen numbers A3 to A18 where the material of the resin molded part 33 is a polymer alloy of a first polymer and a second polymer, for Specimens 30 with specimen numbers A11 and A18, when the material of the insulator 32 is crosslinked polyethylene, the peel strength in the sheet adhesion evaluation is strong, and in addition, the airtightness evaluation is "excellent". However, when the material of the insulator 32 is thermoplastic polyurethane, the peel strength in the sheet adhesion evaluation is weak, and in addition, the airtightness evaluation is "not acceptable". This is considered to be due to the following reason: the proportion of the first polymer in the polymer alloy that is the material of the resin molded part 33 is small (20 parts by mass of the first polymer and 80 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer). Therefore, although the adhesiveness with polyolefin is sufficient, the adhesiveness with thermoplastic polyurethane is insufficient.

[0074] On the other hand, based on the evaluation of Specimens 30 with specimen numbers A3 to A18, when the polymer alloy that is the material of the resin molded part 33 contains 30 to 80 parts by mass of the first polymer and 70 to 20 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer (in the cases of specimen numbers A3 to A10, A12 to A17), in both cases where the material of the insulator 32 is crosslinked polyethylene and thermoplastic polyurethane, a judgment of "acceptable" or above was obtained in the airtightness evaluation. This is considered to be due to the following reason: by setting the content of the first polymer to 30 parts by mass or more, the adhesiveness with thermoplastic polyurethane can be improved, and by setting the content of the second polymer to 20 parts by mass or more, the adhesiveness with polyolefin can be improved.

[0075] In addition, when the polymer alloy that is the material of the resin molded part 33 contains 40 to 70 parts by mass of the first polymer and 60 to 30 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer (in the cases of specimen numbers A4 to A9, A13 to A16), in both cases where the material of the insulator 32 is crosslinked polyethylene and thermoplastic polyurethane, a judgment of "excellent" was obtained in the airtightness evaluation (in Specimens 30 with specimen numbers A4 to A6 containing 70 parts by mass of the first polymer and 30 parts by mass of the second polymer, in Specimens 30 with specimen numbers A4 and A5 having a smaller average dispersion diameter, in both cases where the material of the insulator 32 is crosslinked polyethylene and thermoplastic polyurethane, a judgment of "excellent" was obtained). This is considered to be due to the following reason: by setting the content of the first polymer to 40 parts by mass or more, the adhesiveness with thermoplastic polyurethane can be made higher, and by setting the content of the second polymer to 30 parts by mass or more, the adhesiveness with polyolefin can be made higher.

[0076] In addition, among the specimens 30 with specimen numbers A4 to A6, the mass ratio of the first polymer and the second polymer in the polymer alloy used as the material of the resin molded part 33 is equal, and the average dispersion diameter of the polymer alloy is different. Therefore, in the airtightness evaluation when the material of the insulator 32 is thermoplastic polyurethane, the specimens 30 with specimen numbers A4 and A5 are judged as "excellent", and the specimen 30 with specimen number A6 is judged as "acceptable". This is considered to be caused by the difference in the average dispersion diameter. It can be said that the average dispersion diameter is preferably less than 125 μm, and more preferably 95 μm or less.

[0077] From the above results, it is confirmed that in the wire harness 1 according to the above embodiment, when a polyamide-based polymer is used as the first polymer constituting the polymer alloy used as the material of the resin molded part 3, the adhesiveness between the resin molded part 3 and the sheath 23 made of thermoplastic polyurethane, the ABS sensor cable 21 with the outermost layer made of thermoplastic polyurethane, and the electric parking brake cable 22 with the outermost layer made of polyolefin can be sufficiently ensured.

[0078] The composition and the results of various evaluations of the specimens 30 with specimen numbers B1 to B18 are shown in Table 2 below. In the specimens 30 with specimen numbers B1 to B18, as the first polymer constituting the polymer alloy used as the material of the resin molded part 33, PBT (polybutylene terephthalate) (Toraycon 1401X06 manufactured by Toray) and a polyester-based elastomer (Hytrel 3046 manufactured by Toray-DuPont) (recorded as a polyester-based elastomer in Table 2), which are polyester-based polymers, are used. In addition, as the second polymer, maleic anhydride-modified ethylene-propylene rubber (Admer XE070 manufactured by Mitsui Chemicals) (recorded as an acid-modified polyolefin in Table 2), which is a polyolefin, is used.

[0079] [Table 2]

[0080]

[0081] According to Table 2, in both specimens 30 with specimen numbers B1 and B2, when the material of the insulator 32 is thermoplastic polyurethane, the peel strength in the sheet adhesion evaluation is strong, and in addition, the airtightness evaluation is "excellent". However, in both cases where the material of the insulator 32 is cross-linked polyethylene, the peel strength in the sheet adhesion evaluation is weak, and in addition, the airtightness evaluation is "unacceptable". This is considered to be due to the following reasons: Only the first polymer is used in the material of the resin molded part 33. Therefore, although the adhesiveness with thermoplastic polyurethane is sufficient, the adhesiveness with polyolefin is insufficient.

[0082] In addition, according to the evaluation of the specimens 30 with specimen numbers B3 to B18 where the material of the resin molded part 33 is a polymer alloy of a first polymer and a second polymer, for the specimens 30 with specimen numbers B11 and B18, when the material of the insulator 32 is crosslinked polyethylene, the peel strength in the sheet adhesion evaluation is strong, and in addition, the airtightness evaluation is "excellent". However, when the material of the insulator 32 is thermoplastic polyurethane, the peel strength in the sheet adhesion evaluation is weak, and in addition, the airtightness evaluation is "not acceptable". This is considered to be caused by the following reason: the proportion of the first polymer in the polymer alloy that is the material of the resin molded part 33 is small (20 parts by mass of the first polymer and 80 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer). Therefore, although the adhesiveness to polyolefin is sufficient, the adhesiveness to thermoplastic polyurethane is insufficient.

[0083] On the other hand, according to the evaluation of the specimens 30 with specimen numbers B3 to B18, when the polymer alloy that is the material of the resin molded part 33 contains 30 to 80 parts by mass of the first polymer and 70 to 20 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer (in the cases of specimen numbers B3 to B10, B12 to B17), in both cases where the material of the insulator 32 is crosslinked polyethylene and thermoplastic polyurethane, a judgment of "acceptable" or better was obtained in the airtightness evaluation. This is considered to be due to the following reason: by setting the content of the first polymer to 30 parts by mass or more, the adhesiveness to thermoplastic polyurethane can be improved, and by setting the content of the second polymer to 20 parts by mass or more, the adhesiveness to polyolefin can be improved.

[0084] In addition, when the polymer alloy that is the material of the resin molded part 33 contains 40 to 70 parts by mass of the first polymer and 60 to 30 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer (in the cases of specimen numbers B4 to B9, B13 to B16), in both cases where the material of the insulator 32 is crosslinked polyethylene and thermoplastic polyurethane, a judgment of "excellent" was obtained in the airtightness evaluation (in the specimens 30 with specimen numbers B4 to B6 containing 70 parts by mass of the first polymer and 30 parts by mass of the second polymer, in the specimens 30 with specimen numbers B4 and B5 having a smaller average dispersion diameter, in both cases where the material of the insulator 32 is crosslinked polyethylene and thermoplastic polyurethane, a judgment of "excellent" was obtained). This is considered to be due to the following reason: by setting the content of the first polymer to 40 parts by mass or more, the adhesiveness to thermoplastic polyurethane can be made higher, and by setting the content of the second polymer to 30 parts by mass or more, the adhesiveness to polyolefin can be made higher.

[0085] In addition, in Specimens 30 with Specimen Numbers B4 to B6, the mass ratio of the first polymer and the second polymer in the polymer alloy used as the material of the resin molded article 33 is equal, and the average dispersion diameter of the polymer alloy is different. Therefore, in the airtightness evaluation when the material of the insulator 32 is thermoplastic polyurethane, Specimens 30 with Specimen Numbers B4 and B5 are judged as "excellent", and Specimen 30 with Specimen Number B6 is judged as "acceptable". This is considered to be caused by the difference in the average dispersion diameter. It can be said that the average dispersion diameter is preferably less than 125 μm, and more preferably 98 μm or less.

[0086] From the above results, it was confirmed that in the wire harness 1 according to the above-described embodiment, when a polyester-based polymer is used as the first polymer constituting the polymer alloy used as the material of the resin molded article 3, the adhesiveness between the resin molded article 3 and the sheath 23 made of thermoplastic polyurethane, the ABS sensor cable 21 with a thermoplastic polyurethane outermost layer, and the electric parking brake cable 22 with a polyolefin outermost layer can be sufficiently ensured.

[0087] The composition and the results of various evaluations of Specimens 30 with Specimen Numbers C1 to C10 are shown in Table 3 below. In Specimens 30 with Specimen Numbers C1 to C10, as the first polymer constituting the polymer alloy used as the material of the resin molded article 33, thermoplastic polyurethane (TPU) (Elastollan 1190A manufactured by BASF) was used. In addition, as the second polymer, an ethylene-propylene rubber modified with maleic anhydride as a polyolefin (Admer XE070 manufactured by Mitsui Chemicals) was used (described as acid-modified polyolefin in Table 3).

[0088] [Table 3]

[0089]

[0090] According to Table 3, in Specimen 30 with Specimen Number C1, when the material of the insulator 32 is crosslinked polyethylene, the peel strength in the sheet adhesion evaluation is weak, and in addition, the airtightness evaluation is "unacceptable". This is considered to be caused by the following reason: only the first polymer is used in the material of the resin molded article 33, so the adhesiveness with the polyolefin is insufficient.

[0091] In addition, based on the evaluation of Specimens 30 with specimen numbers C3 to C10, where the material of the resin molded part 33 is a polymer alloy of a first polymer and a second polymer, for Specimen 30 of C10, when the material of the insulator 32 is crosslinked polyethylene, the peel strength in the sheet adhesion evaluation is strong, and in addition, the airtightness evaluation is "excellent". However, when the material of the insulator 32 is thermoplastic polyurethane, the peel strength in the sheet adhesion evaluation is weak, and in addition, the airtightness evaluation is "not acceptable". This is considered to be due to the following reason: the proportion of the first polymer in the polymer alloy that is the material of the resin molded part 33 is small (20 parts by mass of the first polymer and 80 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer). Therefore, although the adhesiveness to polyolefin is sufficient, the adhesiveness to thermoplastic polyurethane is insufficient.

[0092] In addition, based on the evaluation of Specimens 30 with specimen numbers C2 to C10, when the polymer alloy that is the material of the resin molded part 33 contains 30 to 80 parts by mass of the first polymer and 70 to 20 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer (in the case of specimen numbers C2 to C9), in both cases where the material of the insulator 32 is crosslinked polyethylene and thermoplastic polyurethane, a determination of "acceptable" or better was obtained in the airtightness evaluation. This is considered to be due to the following reason: by setting the content of the first polymer to 30 parts by mass or more, the adhesiveness to thermoplastic polyurethane can be improved, and by setting the content of the second polymer to 20 parts by mass or more, the adhesiveness to polyolefin can be improved.

[0093] In addition, when the polymer alloy that is the material of the resin molded part 33 contains 40 to 70 parts by mass of the first polymer and 60 to 30 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer (in the case of specimen numbers C3 to C8), in both cases where the material of the insulator 32 is crosslinked polyethylene and thermoplastic polyurethane, a determination of "excellent" was obtained in the airtightness evaluation (in Specimens 30 with specimen numbers C3 to C5 containing 70 parts by mass of the first polymer and 30 parts by mass of the second polymer, in Specimens 30 with specimen numbers C3 and C4 having a smaller average dispersion diameter, in both cases where the material of the insulator 32 is crosslinked polyethylene and thermoplastic polyurethane, a determination of "excellent" was obtained). This is considered to be due to the following reason: by setting the content of the first polymer to 40 parts by mass or more, the adhesiveness to thermoplastic polyurethane can be made higher, and by setting the content of the second polymer to 30 parts by mass or more, the adhesiveness to polyolefin can be made higher.

[0094] In addition, in the specimens 30 with specimen numbers C3 to C5, the mass ratio of the first polymer and the second polymer in the polymer alloy that is the material of the resin molded part 33 is equal, and the average dispersion diameter of the polymer alloy is different. Therefore, in the airtightness evaluation when the material of the insulator 32 is thermoplastic polyurethane, the specimens 30 with specimen numbers C3 and C4 are judged as "excellent", and the specimen 30 with specimen number C5 is judged as "acceptable". This is considered to be due to the difference in the average dispersion diameter. It can be said that the average dispersion diameter is preferably less than 120 μm, and more preferably 100 μm or less.

[0095] From the above results, it is confirmed that in the wire harness 1 according to the above-described embodiment, when thermoplastic polyurethane is used as the first polymer constituting the polymer alloy that is the material of the resin molded part 3, the adhesiveness between the resin molded part 3 and the sheath 23 made of thermoplastic polyurethane, the ABS sensor cable 21 with the outermost layer made of thermoplastic polyurethane, and the electric parking brake cable 22 with the outermost layer made of polyolefin can be sufficiently ensured.

[0096] (Summary of Embodiments)

[0097] Next, referring to the symbols and the like in the embodiments, the technical idea grasped from the embodiments described above is described. However, the symbols and the like in the following description do not limit the constituent elements in the claims to the specific components shown in the embodiments.

[0098] [1] A wire harness (1) includes: a multi-core cable (2) having a cable group (21, 22) composed of multiple cables and a sheath (23) provided around the cable group (21, 22), and a resin molded part (3) that covers the sheath (23) and the cable group (21, 22) at a cable bifurcation part (4) where the cable group (21, 22) bifurcates from the end of the sheath (23) of the multi-core cable (2); the outermost layer of each cable constituting the cable group (21, 22) is made of polyolefin or thermoplastic polyurethane; when the sheath (23) is made of polyolefin, the cable group (21, 22) includes at least one cable having an outermost layer made of thermoplastic polyurethane; when the sheath (23) is made of thermoplastic polyurethane, the cable group (21, 22) includes at least one cable having an outermost layer made of polyolefin; the resin molded part (3) is composed of a polymer alloy including a first polymer containing at least one of a polyamide-based polymer, a polyester-based polymer, and thermoplastic polyurethane and a second polymer containing polyolefin.

[0099] [2] The wire harness (1) according to the above [1], wherein the polyolefin constituting the outermost layer of the cable is crosslinked polyethylene or a crosslinked ethylene-vinyl acetate copolymer.

[0100] [3] The wire harness (1) according to [1] or [2] above, wherein the second polymer is an acid-modified polyolefin.

[0101] [4] The wire harness (1) according to any one of [1] to [3] above, wherein, based on 100 parts by mass in total of the first polymer and the second polymer, the polymer alloy contains 30 to 80 parts by mass of the first polymer and 70 to 20 parts by mass of the second polymer.

[0102] [5] The wire harness (1) according to any one of [1] to [4] above, wherein the average dispersion diameter of the polymer alloy is less than 120 μm.

[0103] [6] The wire harness (1) according to any one of [1] to [5] above, wherein the cable sets (21, 22) include an ABS sensor cable (21) and an electric parking brake cable (22).

[0104] [7] The wire harness (1) according to any one of [1] to [6] above, wherein, based on 100 parts by mass in total of the first polymer and the second polymer, the polymer alloy contains 40 to 70 parts by mass of the first polymer and 60 to 30 parts by mass of the second polymer.

[0105] The embodiments and examples of the present invention have been described above, but the present invention is not limited to the above embodiments and examples, and various modifications can be made without departing from the spirit of the invention. In addition, the above-described embodiments and examples do not limit the invention described in the claims. It should also be noted that not all combinations of the features described in the embodiments and examples are necessarily required for the method of solving the problems of the invention.

[0106] For example, a resin composition for a resin molded article used for covering a first resin molded article made of a polyolefin and a second resin molded article made of a thermoplastic polyurethane and performing resin molding, the resin composition for a resin molded article may contain a polymer alloy, the polymer alloy being a polymer alloy of a first polymer containing at least one of a polyamide-based polymer, a polyester-based polymer, and a thermoplastic polyurethane and a second polymer containing a polyolefin.

Claims

1. A wire harness, comprising: a multi-core cable having a cable group composed of a plurality of cables and a sheath provided around the cable group; and a resin molded article covering the sheath and the cable group at a cable bifurcation portion where the cable group bifurcates from an end portion of the sheath of the multi-core cable, the outermost layer of each of the cables constituting the cable group is made of polyolefin or thermoplastic polyurethane, when the sheath is made of polyolefin, the cable group includes at least one cable having an outermost layer made of thermoplastic polyurethane, when the sheath is made of thermoplastic polyurethane, the cable group includes at least one cable having an outermost layer made of polyolefin, the resin molded article is composed of a polymer alloy of a first polymer containing at least one of a polyamide-based polymer, a polyester-based polymer, and thermoplastic polyurethane and a second polymer containing polyolefin, the polymer alloy contains 30 to 80 parts by mass of the first polymer and 70 to 20 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer.

2. The wire harness according to claim 1, wherein the polyolefin constituting the outermost layer of the cable is crosslinked polyethylene or a crosslinked ethylene-vinyl acetate copolymer.

3. The wire harness according to claim 1 or 2, wherein the second polymer is an acid-modified polyolefin.

4. The wire harness according to claim 1 or 2, wherein the average dispersion diameter of the polymer alloy is less than 120 μm.

5. The wire harness according to claim 1 or 2, wherein the cable group includes an ABS sensor cable and an electric parking brake cable.

6. A resin composition for covering and resin molding a first resin molded article made of polyolefin and a second resin molded article made of thermoplastic polyurethane, the resin composition contains a polymer alloy, which is a polymer alloy of a first polymer containing at least one of a polyamide-based polymer, a polyester-based polymer, and thermoplastic polyurethane and a second polymer containing polyolefin, the polymer alloy contains 30 to 80 parts by mass of the first polymer and 70 to 20 parts by mass of the second polymer with respect to a total of 100 parts by mass of the first polymer and the second polymer.

7. The resin composition according to claim 6, wherein the second polymer is an acid-modified polyolefin.

8. The resin composition according to claim 6 or 7, wherein the average dispersion diameter of the polymer alloy is less than 120 μm.

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