Insulated wire and structure

Abstract

The utility model provides an insulated wire and a structure formed by bonding the insulated wire and other parts by using an adhesive, the insulated wire is provided with an insulator made of thermoplastic polyurethane on the outermost layer, and a good bonding state with relatively high peel strength can be realized in the bonding process by using the adhesive. Provided is an insulated wire (1) in which a linear conductor (10) is insulated and covered, the insulated wire (1) comprising an insulator (12) comprising a thermoplastic polyurethane on the outermost layer, and a plurality of wave-line-shaped recesses and projections provided on the surface of the insulator (12) in a direction perpendicular to the longitudinal direction of the insulated wire (1), the arithmetic average height Sa of the surface of the insulator (12) is 4.4 [mu] m or more and 12 [mu] m or less.

Description

TECHNICAL FIELD

[0001] The utility model relates to insulated wire and structure. BACKGROUND

[0002] Now, a molded processed wire is known, which is configured such that an insulator composed of thermoplastic polyurethane that covers the outer periphery of a conductor wire has a predetermined surface roughness, and the end of the insulator is covered by a molded resin shaped body (see Patent Document 1).

[0003] In the molded processed wire of Patent Document 1, the surface roughness of the insulator is adjusted to be within a predetermined range to improve the adhesion of the insulator to the molded resin shaped body, thereby improving the airtightness of the inside of the molded resin shaped body.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-162566 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In Patent Document 1, a range of arithmetic average roughness Ra that can improve the adhesion of the insulator to the molded resin shaped body is disclosed. The present inventors have considered that, similarly to the improvement of the adhesion of the insulator to the molded resin shaped body by the technology of Patent Document 1, if the surface state of the insulator that is suitable for adhesion using an adhesive can be achieved, a desirable adhesion state is obtained in the adhesion of the insulator to other parts and the like, and have repeatedly conducted research.

[0009] The utility model discloses an insulated wire and structure that the insulated wire and other parts are adhered by an adhesive, the insulated wire has an insulator composed of thermoplastic polyurethane in the outermost layer and can achieve a good adhesion state with a large peeling strength in the adhesion using an adhesive.

[0010] SOLUTION TO THE PROBLEM

[0011] The utility model discloses an insulated wire and structure that the insulated wire and other parts are adhered by an adhesive, the insulated wire has an insulator composed of thermoplastic polyurethane in the outermost layer and can achieve a good adhesion state with a large peeling strength in the adhesion using an adhesive.

[0012] That is, the utility model discloses the scheme as follows.

[0013] One aspect of the present application relates to an insulated electric wire. The insulated electric wire is an insulated electric wire in which a linear conductor is covered with insulation. The insulated electric wire is characterized in that an insulator composed of a thermoplastic polyurethane is provided on the outermost layer, and a plurality of wavy concave-convexes are provided on the surface of the insulator in a direction perpendicular to the length direction of the insulated electric wire. The arithmetic mean height Sa of the surface of the insulator is 4.4 μm or more and 12 μm or less.

[0014] Another aspect of the present application relates to the insulated electric wire according to the first aspect. The insulated electric wire is characterized in that the arithmetic mean height Sa is 5.8 μm or more.

[0015] Still another aspect of the present application relates to the insulated electric wire according to the first aspect. The insulated electric wire is characterized in that the arithmetic mean height Sa is 10 μm or more.

[0016] A further aspect of the present application relates to a structure. The structure is characterized in that the structure includes the insulated electric wire according to any one of the first to third aspects, and a member formed of an ethylene-propylene rubber that is bonded to the surface of the insulator of the insulated electric wire by an adhesive.

[0017] Effects of the present application are as follows.

[0018] According to the present application, it is possible to provide an insulated electric wire and a structure in which the insulated electric wire and another member are bonded by an adhesive. The insulated electric wire has an insulator composed of a thermoplastic polyurethane on the outermost layer, and it is possible to achieve a good bonding state with a high peeling strength in bonding using an adhesive. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 FIG. 1 is a radial cross-sectional view of a cable that shows an example of an insulated electric wire according to an embodiment of the present application.

[0020] Figure 2 FIG. 2 is a cross-sectional view that shows an example of the configuration of a clip-in detection device that includes the cable according to the embodiment of the present application.

[0021] Figure 3 (a) of FIG. 3 is a photograph that shows the appearance of a cable, Figure 3 (b) of FIG. 3 is an observation image of the surface of a sheath under a laser microscope.

[0022] Figure 4 FIG. 4 is a table that shows observation images of the surface of a sheath and various parameters of surface roughness at each extrusion temperature at the time of extrusion molding of the sheath.

[0023] Figure 5 FIG. 5 is a table that shows observation images of the surface of a sheath and various parameters of surface roughness at each extrusion temperature at the time of extrusion molding of the sheath.

[0024] Figure 6 FIG. 6 is a schematic view that shows the method of a shear peeling test.

[0025] Figure 7 is a graph showing the relationship between the arithmetic average height Sa of the surface of the sheath after the peeling test by the cable and the peeling strength.

[0026] Figure 8 (a) of is an SEM (scanning electron microscope) image of the surface of the sheath after the cable with the arithmetic average height Sa of the surface of the sheath peeled from the protector is 1 μm. Figure 8 (b) of is an SEM image of the surface of the sheath after the cable with the arithmetic average height Sa of the surface of the sheath peeled from the protector is 10 μm.

[0027] Explanation of symbols

[0028] 1 - cable, 10 - conductor, 11 - insulator, 12 - sheath, 2 - adhesive, 3 - clamping detection device, 40 - protector. DETAILED DESCRIPTION

[0029] The insulated electric wire of the embodiment of the present application is an insulated electric wire in which a linear conductor is covered with insulation, has an insulator composed of a thermoplastic polyurethane at the outermost layer, and has a plurality of wavy concavities and convexities on the surface of the insulator in a direction perpendicular to the length direction of the insulated electric wire, the arithmetic average height Sa of the surface of the insulator being 4.4 μm or more and 12 μm or less.

[0030] The insulated electric wire of the embodiment of the present application further includes a cable having a sheath. In this case, the sheath corresponds to the insulator at the outermost layer.

[0031] The insulator at the outermost layer is formed by extrusion coating of the thermoplastic polyurethane. The extrusion coating can use a known method using an extruder.

[0032] The thermoplastic polyurethane constituting the insulator at the outermost layer can use, for example, polyester-based polyurethane (adipate-based, caprolactone-based, polycarbonate-based), polyether-based polyurethane. In particular, from the viewpoint of moisture and heat resistance and the like, it is preferable to use polyether-based polyurethane.

[0033] Furthermore, if necessary, additives such as a processing aid, a flame retardant, a flame retardant aid, a crosslinking agent, a crosslinking aid, an antioxidant, an ultraviolet absorber, a copper inhibitor, a lubricant, an inorganic filler, an adhesion-imparting agent, a stabilizer, carbon black, a coloring agent, and the like can be added to the thermoplastic polyurethane.

[0034] A wave-shaped concave-convex is provided on the surface of the outermost insulator to improve the sliding property of the surface, thereby facilitating the arrangement of the insulated wire. Further, by providing the wave-shaped concave-convex on the surface of the outermost insulator, the peel strength when the insulated wire is bonded to other parts or the like with an adhesive is improved. This is because the adhesive applied to the surface of the outermost insulator enters the wave-shaped concave-convex and hardens, resulting in an anchoring effect.

[0035] Further, in the case where the wave-shaped concave-convex is formed to a large extent with the arithmetic mean height Sa of the surface of the insulator being 4.4 μm or more, a good bonding state with a large peel strength is obtained.

[0036] Further, in order to make the peel strength higher, the wave-shaped concave-convex is preferably formed to a large extent with the arithmetic mean height Sa being 5.8 μm or more, and further, in order to obtain a desirable bonding state in which material failure occurs at the time of peeling, the wave-shaped concave-convex is more preferably formed to a large extent with the arithmetic mean height Sa being 10 μm or more. In addition, the above-described relationship between the arithmetic mean height Sa of the surface of the insulator and the peel strength after bonding holds true in the case where the insulated wire has a certain degree of size (for example, a diameter of 1 mm or more).

[0037] On the other hand, the larger the wave-shaped concave-convex, the thicker the layer of the applied adhesive, and thus the time required for the hardening of the adhesive increases. For example, in the case of using an adhesive such as a cyanoacrylate-based adhesive that hardens by molecular polymerization in reaction with moisture in the air, the reaction with water is sluggish and the hardening time becomes long due to the thickening of the layer of the adhesive.

[0038] Therefore, by suppressing the size of the wave-shaped concave-convex to a degree where the arithmetic mean height Sa of the surface of the insulator is 12 μm or less, the hardening time of the adhesive can be converged within a practical range.

[0039] The size of the wave-shaped concave-convex can be controlled using the extrusion conditions such as the extrusion temperature and the extrusion speed at the time of extrusion coating of the insulator. For example, by lowering the extrusion temperature or increasing the extrusion speed, the wave-shaped concave-convex (the surface roughness) can be made larger.

[0040] Figure 1 is a radial sectional view of a cable 1 that shows an example of an insulated wire according to an embodiment of the present application. The cable 1 has two wire-shaped conductors 10 each covered with an insulator 11, and a sheath 12 that covers the conductors 10.

[0041] The conductor 10 is composed of, for example, a stranded conductor in which a plurality of wire rods formed of copper, copper alloy, or the like are stranded. The insulator 11 is formed of, for example, an insulating material such as a thermoplastic polyolefin. The sheath 12 is formed of a thermoplastic polyurethane and constitutes the outermost insulator in the cable 1. The sheath 12 is formed by extruding the thermoplastic polyurethane around the two wire-like conductors 10 covered with the insulator 11.

[0042] The cable 1 is used, for example, as a lead wire connected to a cable-shaped pressure-sensitive sensor used in a pinch detection device mounted to an electric sliding door or an electric rear door of a vehicle. In this case, the cable 1 is bonded to a protector that houses the cable-shaped pressure-sensitive sensor.

[0043] Figure 2 is a sectional view showing an example of the configuration of a pinch detection device 3 including the cable 1 as an application example of the cable 1. The pinch detection device 3 is provided with a cable-shaped pressure-sensitive sensor 30, the cable 1 as a lead wire connected to the pressure-sensitive sensor 30, and a protector 40 formed of ethylene propylene diene rubber (EPDM) or the like that houses the pressure-sensitive sensor 30 and the cable 1.

[0044] The pressure-sensitive sensor 30 is housed in a housing hole 41 of the protector 40, and the cable 1 is housed in a housing groove 42 of the protector 40. The protector 40 is fixed to a plate-like portion 50 such as a bracket on the vehicle side by a mounting portion 43 in which a core rod 44 is embedded.

[0045] The pressure-sensitive sensor 30 is provided with an insulator 31 having a hollow portion 32 and electrode wires 33a and 33b covered with a conductive rubber. The electrode wires 33a and 33b are fixed to an inner peripheral portion of the insulator 31 and are arranged in a spiral shape along the hollow portion 32 in a state of being separated while sandwiching the hollow portion 32.

[0046] In the pinch detection device 3, if the insulator 31 is deformed by an external force, the electrode wire 33a comes into contact with the electrode wire 33b and is conducted, and a current detecting element connected to a circuit including the pressure-sensitive sensor 30 and the cable 1 detects a change in current value. Thus, it is detected that the electrode wire 33a comes into contact with the electrode wire 33b, that is, that a pinch is detected in an electric sliding door or an electric rear door in which the pinch detection device 3 is mounted.

[0047] The cable 1 is bonded to an inner surface of the housing groove 42 with an adhesive 2 such as a cyanoacrylate-based adhesive. As shown in the example of the pinch detection device 3, the cable 1 can achieve a good bonding state with a large peeling strength in bonding to a part formed of ethylene propylene diene rubber.

[0048] That is, according to the embodiments of the present invention, a structure can be provided that includes an insulated wire such as a cable 1 as described in the embodiments of the present invention, and a part made of ethylene propylene rubber bonded to the surface of the outermost insulator of the insulated wire, such as a sheath 12, using an adhesive. In this structure, the insulated wire and the part are fixed in a good bonded state with high peel strength.

[0049] Figure 3 (a) is a photograph showing the appearance of cable 1. Figure 3 (b) is an image of the surface of sheath 12 observed under a laser microscope. Figure 3 The pixels of the observed image in (b) have height (as shown by the bar-shaped color palette on the right) and [other characteristics]. Figure 3 The color corresponding to the position of (b) on the paper in the vertical direction. Figure 3 (a) and Figure 3 The cables in (b) 1 are oriented in the same direction. That is, Figure 3 (a) and Figure 3 The transverse direction in (b) is roughly the same as the length direction of cable 1.

[0050] according to Figure 4 The observation image (b) confirms that the surface of the sheath 12 is provided with a plurality of corrugated protrusions in a direction perpendicular to the length direction of the cable 1. Furthermore, "in a direction perpendicular to the length direction of the cable 1" does not mean a state that is strictly parallel to the direction perpendicular to the length direction of the cable 1, but rather a state in which the average direction in which the plurality of corrugated protrusions extend is significantly closer to the direction perpendicular to the length direction of the cable 1 than the length direction of the cable 1.

[0051] The multiple wavy protrusions perpendicular to the length of the cable 1 are formed during the extrusion process of the sheath 12. During the extrusion process, the surface of the sheath 12 is subjected to a force along the extrusion direction, i.e., the length of the cable 1, resulting in wavy protrusions with an amplitude direction along the length of the cable 1.

[0052] Figure 5 , Figure 4 The results show the evaluation of multiple sheaths 12 that were extruded and coated under the same extrusion speed (40 mm / min) but different extrusion temperatures. Figure 5 , Figure 4 This is an observation image of the surface of the sheath 12 at various extrusion temperatures during the extrusion molding of the sheath 12, and a table showing various parameters of surface roughness according to ISO 25178 (arithmetic mean height Sa, maximum height Sz, aspect ratio of surface properties Str, arithmetic mean curvature of the mountain peak Spc, and unfolded area ratio of the interface Sdr).

[0053] Figure 5 , Figure 4 Image A is an observation image of the surface of the sheath 12 under a laser microscope, and image B is an observation image containing height information at various locations. Each pixel in image B has a height (as indicated by the bar-shaped color palette on the right) as shown. Figure 5 , Figure 4 The color corresponding to the position (vertical direction) on the paper.

[0054] from Figure 5 , Figure 6 The relationship between extrusion temperature and various parameters of surface roughness shows that the higher the extrusion temperature, the smaller the surface roughness, that is, the smaller the wavy unevenness.

[0055] The following describes the method and results of the shear peel test performed to investigate the adhesiveness of the surface of the sheath 12 of cable 1.

[0056] Figure 6 This is a schematic diagram illustrating the method of this shear peel test. In this shear peel test, a sheet 120 made of thermoplastic polyurethane with a longitudinal length of 150mm × transverse length of 6mm × thickness of 3mm and a sheet 400 made of ethylene propylene rubber with a longitudinal length of 150mm × transverse length of 6mm × thickness of 2mm are prepared by cutting the sheath 12 peeled from the cable 1 into a strip.

[0057] Moreover, such as Figure 6 As shown, sheet 120 and sheet 400 are bonded together by applying a force for 1 second in their thickness direction (bonding area is 60mm in the longitudinal direction × 6mm in the transverse direction) using cyanoacrylate adhesive 20 to produce a sample.

[0058] After bonding, a shear peel test was performed on the resulting specimens to determine the peel strength. In this shear peel test, Figure 7 In the direction indicated by the arrow, sheets 120 and 400 were stretched at a stretching speed of 100 mm / min.

[0059] Figure 7 This is a graph showing the relationship between the arithmetic mean height Sa of the surface of the sheath 12 obtained through this shear peel test and the peel strength.

[0060] Figure 7 The solid line in the graph shows the relationship between the arithmetic mean height Sa and the average peel strength in the range from the arithmetic mean height Sa to 10 μm, while the dashed line shows the relationship between the arithmetic mean height Sa and the average peel strength in the range from the arithmetic mean height Sa to 10 μm.

[0061] according to Figure 7It can be seen that within the range of the arithmetic mean height Sa up to approximately 10 μm, the peel strength increases with increasing arithmetic mean height Sa. Furthermore, according to... Figure 7 It is evident that when the arithmetic mean height Sa is 4.4 μm or higher, the average peel strength becomes a desired value of approximately 25 N or higher, and when the arithmetic mean height Sa is 5.8 μm or higher, the average peel strength becomes an even higher value of approximately 30 N or higher. Furthermore, in the range where the arithmetic mean height Sa exceeds 10 μm, the peel strength decreases with increasing arithmetic mean height Sa because a larger arithmetic mean height Sa results in a thicker adhesive layer, which in turn slows down the reaction with water and reduces the curing rate of the adhesive.

[0062] like Figure 8 As shown, the greater the arithmetic mean height Sa of the surface of the sheath 12, the greater the anchoring effect, and therefore the greater the peel strength at the interface between the sheath 12 and the fully cured adhesive. Moreover, when the arithmetic mean height Sa is 10 μm or more, an ideal bonding state that does not result in material failure during peeling can be obtained.

[0063] On the other hand, the greater the arithmetic mean height Sa of the surface of the sheath 12, the thicker the adhesive layer, which in turn slows down the reaction with water and reduces the hardening rate of the adhesive. In this peel test, when the arithmetic mean height Sa is greater than 12, peeling occurs in a state where the adhesive has not hardened, thereby reducing the peel strength.

[0064] Figure 8 (a) is a SEM (scanning electron microscope) image of the surface of the sheath 12 after the cable 1 has been peeled from the surface of the sheath 12 made of ethylene propylene rubber protector 40 with an arithmetic mean height Sa of 1 μm.

[0065] according to Figure 8 The SEM image of (a) confirms that a small amount of adhesive 21 remains on the surface of the sheath 12 during the interface stripping (stripping at the interface between the sheath 12 of the cable 1 and the hardened adhesive).

[0066] It is believed that in Figure 8 The SEM image of (a) shows that the interface peeling occurred in the stripping test of cable 1 because the arithmetic mean height Sa was too small to obtain a sufficient anchoring effect.

[0067] Figure 8 (b) is a SEM image of the surface of the sheath 12 after the cable 1 has been stripped from the surface of the sheath 12 made of ethylene propylene rubber protector 40, with an arithmetic mean height Sa of 10 μm.

[0068] according to Figure 8The SEM image of (b) can confirm that a portion 22 of the protector remaining on the surface of the cable 1 due to material damage at the time of peeling exists on the surface of the sheath 12.

[0069] It is considered that material damage occurs in the peeling test of the cable 1 shown in the SEM image of (b) because the arithmetic mean height Sa is a size at which a sufficient anchoring effect can be obtained. Also, from the fact that the adhesive does not peel off in an unhardened state, it is considered that the adhesive is firmly bonded to the surface of the insulator 12. Figure 8 ​ The SEM image of (b) does not confirm a trace of the adhesive peeling off in an unhardened state.

[0070] (EFFECTS OF THE EMBODIMENTS)

[0071] The insulating electric wire according to the embodiment of the present application, by controlling the size of the wave-shaped concavo-convex of the surface of the insulator composed of thermoplastic polyurethane, in the bonding using the adhesive, a good bonding state with a large peeling strength can be obtained in a short bonding time.

[0072] (SUMMARY OF THE EMBODIMENTS)

[0073] Next, the technical ideas grasped from the above-described embodiments are described with reference to the symbols and the like in the embodiments. Among them, each symbol and the like in the following description does not limit the constituent elements in the claims to the components and the like specifically shown in the embodiments.

[0074] [1] An insulating electric wire 1 in which a conductor 10 in a wire shape is covered with insulation, wherein an insulator 12 composed of thermoplastic polyurethane is provided in an outermost layer, and a plurality of wave-shaped concavo-convexes in a direction perpendicular to a length direction of the insulating electric wire 1 are provided on a surface of the insulator 12, and an arithmetic mean height Sa of the surface of the insulator 12 is 4.4 μm or more and 12 μm or less.

[0075] [2] The insulating electric wire 1 according to the above [1], wherein the arithmetic mean height Sa is 5.8 μm or more.

[0076] [3] The insulating electric wire 1 according to the above [1], wherein the arithmetic mean height Sa is 10 μm or more.

[0077] [4] A structure 3 comprising: the insulating electric wire 1 according to any one of the above [1] to [3]; and a member 40 formed of an ethylene-propylene rubber bonded to the surface of the insulator 12 of the insulating electric wire 1 with an adhesive 2.

[0078] ​The embodiments of the present application have been described above with the application, but the present application is not limited to the above-described embodiments, and various modifications can be implemented without departing from the gist of the present application. Furthermore, the constituent elements of the above-described embodiments can be arbitrarily combined within the scope of the gist of the present application. Furthermore, the embodiments described in the above do not limit the application of the claims. Furthermore, it should be noted that all the feature combinations described in the embodiments are not necessarily essential for the solution to the problem of the application.

Claims

1. An insulated electric wire which is an insulated electric wire in which a linear conductor is covered with insulation, characterized by having an insulator composed of a thermoplastic polyurethane at an outermost layer, providing a plurality of corrugated projections and depressions in a wave shape on a surface of the insulator in a direction perpendicular to a length direction of the insulated electric wire, an arithmetic mean height Sa of the surface of the insulator being 4.4 μm or more and 12 μm or less.

2. The insulated electric wire according to claim 1, characterized in that the arithmetic mean height Sa is 5.8 μm or more.

3. The insulated electric wire according to claim 1, characterized in that the arithmetic mean height Sa is 10 μm or more.

4. A structure, characterized by provided with the insulated electric wire according to any one of claims 1 to 3; and a member formed of an ethylene-propylene rubber which is bonded to the surface of the insulator of the insulated electric wire with an adhesive.

Images