Protective tape for wire harness

Abstract

Provided is a protective tape for a wire harness, with which excellent tape winding workability is attained, and wear resistance and suppression of peeling at a tape terminal are achieved. A protective tape 10 for a wire harness has a base material 102 and an adhesive layer 104 formed on the base material 102. The base material 102 contains thermoplastic resin, and has a thickness of 120 μm-190 μm inclusive, a 10% modulus (N / 19 mm width) of 12.5-18.5 inclusive, and a rewinding adhesive force (N / 19 mm width) of 0.8-4.5 inclusive.

Description

Wire harness protection tape

[0001] The present invention relates to a protective tape for a wire harness.

[0002] Patent Document 1 describes a pressure-sensitive adhesive resin tape for wire harness protection, which comprises a resin substrate and a pressure-sensitive adhesive layer provided thereon, the pressure-sensitive adhesive layer being formed from a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition is described as comprising 100 parts by mass (non-volatile content) of a base resin comprising a mixture of natural rubber latex and synthetic rubber latex, 40 to 120 parts by mass of a rosin-based tackifying resin having a softening point of 130 to 135°C, and 1 to 15 parts by mass of a low-molecular-weight polyisoprene having a weight-average molecular weight of 15,000 to 40,000.

[0003] Japanese Patent Application Laid-Open No. 2018-178008

[0004] However, the wire harness protective tape of Patent Document 1 was unable to improve all of the tape winding workability, the prevention of tape end peeling, and the abrasion resistance in a balanced manner.

[0005] An object of the present invention is to provide a protective tape for a wire harness which is excellent in tape winding workability, prevention of tape end peeling, and abrasion resistance.

[0006] The wire harness protective tape of the present invention has a substrate and an adhesive layer formed on the substrate, and is characterized in that the substrate contains a thermoplastic resin, has a thickness of 120 μm or more and 190 μm or less, a 10% modulus (N / 19 mm width) of 12.5 or more and 18.5 or less, and an unwinding adhesive strength (N / 19 mm width) of 0.8 or more and 4.5 or less.

[0007] The protective tape for a wire harness of the present invention exhibits the effects of excellent tape winding workability, suppression of tape end peeling, and excellent abrasion resistance.

[0008] FIG. 1 is a cross-sectional view of a wire harness protection tape according to an embodiment.

[0009] Hereinafter, a wire harness protection tape according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment. Furthermore, the components in the following embodiments include those that can be easily imagined by a person skilled in the art or those that are substantially the same.

[0010] [Embodiment] An embodiment will be described with reference to Fig. 1. The present embodiment relates to a wire harness protection tape. Fig. 1 shows a wire harness protection tape according to an embodiment.

[0011] The wire harness protective tape 10 of this embodiment is suitable for use in automotive wire harnesses. The wire harness protective tape 10 of this embodiment is used when bundling wire harnesses or when fixing a wire harness protective member to a wire harness. Specifically, it can be used by wrapping the tape around a bundling position or a fixing position.

[0012] The wire harness protective tape 10 of this embodiment has a substrate 102 and an adhesive layer 104 formed on the substrate 102. The substrate 102 contains a thermoplastic resin and has a thickness of 120 μm or more and 190 μm or less. Furthermore, the 10% modulus (N / 19 mm width) is 12.5 or more and 18.5 or less, and the unwinding adhesive strength (N / 19 mm width) is 0.8 or more and 4.5 or less. The wire harness protective tape 10 of this embodiment can achieve a balanced improvement in all of the tape winding workability, the suppression of tape end peeling, and the abrasion resistance.

[0013] In conventional wire harnesses, thick polyvinyl chloride (PVC) tape or polypropylene (PP) tape with added abrasion resistance has been used to bundle and protect electric wires. One issue with thick tape is that the ends of the tape tend to peel off after bundling. While efforts have been made to address this issue by increasing the tape's unwinding adhesive strength to prevent peeling, this also reduces the ease of tape wrapping when bundling electric wires. Alternatively, the peeled areas have been re-secured with thinner tape, but this requires additional material costs and labor. Therefore, there has been a demand for a tape that does not cause peeling at the ends of the tape and that also allows for easy tape wrapping.

[0014] However, if the unwinding adhesive strength is reduced to improve workability during tape winding, tape edge peeling occurs after winding onto the electric wire. Two factors that cause edge peeling include low adhesive strength and shrinkage of the substrate after the tape is peeled off. Therefore, the inventors have discovered that, because excessive adhesive strength places a heavy burden on the operator, it is necessary to use a substrate that is not too adhesive and is resistant to shrinkage (deformation). Furthermore, by exploring the ranges of the tape's 10% modulus, unwinding adhesive strength, and substrate thickness, the inventors have found that a tape that does not experience edge peeling, has good workability during tape winding, and is also excellent in abrasion resistance can be obtained.

[0015] In other words, the substrate 102 is a film made of a thermoplastic resin. As the thermoplastic resin, at least one selected from the group consisting of polyvinyl chloride (PVC), polypropylene, and polyethylene is preferably used. Among these, polyvinyl chloride is more preferably used.

[0016] The pressure-sensitive adhesive layer 104 is typically formed from a pressure-sensitive adhesive composition. Examples of the base material of the pressure-sensitive adhesive composition include rubber-based natural rubber latexes such as unmodified natural rubber latex and acrylic-modified natural rubber latex, and acrylic polymers. Specifically, from the viewpoint of unwind adhesive strength, at least one selected from the group consisting of unmodified natural rubber latex, acrylic-modified natural rubber latex, and acrylic polymers is preferably used. In addition to the base material, known additives can be blended into the pressure-sensitive adhesive composition as needed. Examples of additives include tackifying resins such as rosin ester resins, terpene resins, and aliphatic and aromatic hydrocarbon resins; softeners such as low-molecular-weight isoprene rubber (IR) and polyisobutylene; and antioxidants such as phenolic antioxidants.

[0017] The pressure-sensitive adhesive layer 104 is formed on the substrate 102 by a known method. For example, a pressure-sensitive adhesive composition is applied to the substrate 102 using various coaters and then dried to form the pressure-sensitive adhesive layer. Separately, a pressure-sensitive adhesive layer may be formed on a separator and then transferred onto the substrate 102. Therefore, in the obtained wire harness protection tape 10 of the present embodiment, the pressure-sensitive adhesive layer 104 contains natural rubber latex and an acrylic polymer. Specifically, from the viewpoint of unwinding adhesive strength, the pressure-sensitive adhesive layer 104 contains at least one selected from the group consisting of unmodified natural rubber latex, acrylic-modified natural rubber latex, and an acrylic polymer. The pressure-sensitive adhesive layer 104 preferably has a thickness (glue thickness) of 5 μm or more and 50 μm or less.

[0018] The 10% modulus and unwind adhesive strength of the wire harness protection tape 10 of this embodiment can be controlled by appropriately adjusting the type, composition ratio, and thickness of the raw material components of the substrate 102 and adhesive layer 104.

[0019] The wire harness protective tape 10 of the present embodiment may include layers other than the substrate 102 and the adhesive layer 104, if necessary. For example, a primer layer such as a nitrile rubber (NBR)-based primer layer may be provided between the substrate 102 and the adhesive layer 104. The provision of the primer layer can improve the adhesion of the adhesive layer 104 to the substrate 102.

[0020] [Examples] The present invention will be further explained below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0021] Example 1: A nitrile rubber (NBR) primer layer and a rubber-based adhesive layer were formed on a 140 μm-thick polyvinyl chloride (PVC) substrate to obtain a wire harness protection tape. Specifically, the adhesive layer contained unmodified natural rubber latex and acrylic-modified natural rubber latex, and had a thickness ranging from 5 μm to 50 μm. The 10% modulus (N / 19 mm width) and unwound adhesive strength (N / 19 mm width) of the obtained wire harness protection tape 10 are shown in Table 1.

[0022] Examples 2 to 6 Wire harness protective tapes were obtained by forming a primer layer and a pressure-sensitive adhesive layer on the substrate in the same manner as in Example 1, except that the thickness of the polyvinyl chloride (PVC)-containing substrate, the blending ratio of the main agent in the pressure-sensitive adhesive layer, and the thickness of the pressure-sensitive adhesive layer were appropriately changed. The thickness of the pressure-sensitive adhesive layer was in the range of 5 μm to 50 μm. The 10% modulus (N / 19 mm width) and unwound adhesive strength (N / 19 mm width) of the obtained wire harness protective tape 10 are also shown in Table 1.

[0023] Comparative Examples 1 to 5: Wire harness protective tapes were obtained by forming a primer layer and a pressure-sensitive adhesive layer on the substrate in the same manner as in Example 1, except that the thickness of the polyvinyl chloride (PVC)-containing substrate, the blending ratio of the main agent contained in the pressure-sensitive adhesive layer, and the thickness of the pressure-sensitive adhesive layer were appropriately changed. The thickness of the pressure-sensitive adhesive layer was in the range of 5 μm to 50 μm. The 10% modulus (N / 19 mm width) and unwound adhesive strength (N / 19 mm width) of the obtained wire harness protective tape 10 are also shown in Table 1.

[0024] [Measurement Method] [Tensile Test (10% Modulus)] A wire harness protection tape (tape width: 19 mm) was peeled off at a speed of 5 mm / s using a tensile tester with a chuck gripping distance of 100 mm in accordance with JIS Z 0237. After peeling, the strength was read when the tape had stretched 10 mm (10%).

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[0026] [Thickness] According to JIS C 2107, five 19 mm wide test pieces are cut out from the roll using a dial gauge, and after leaving them for 5 minutes or more to remove strain, the upper surface of the gauge is gently lowered onto the surface of the test piece, and the minimum value is read.In addition, for the substrate containing polyvinyl chloride (PVC), the thickness is also determined in advance in the same manner as above.Then, the thickness of the substrate is subtracted from the minimum value read for the above test piece to obtain the thickness of the pressure-sensitive adhesive layer.

[0027] [Evaluation Method] [Judgment of Workability] Based on the measurement results of the adhesive strength at a low unwinding speed, the workability was judged according to the following criteria: ○: 0.8 N / 19 mm width or more and 4.5 N / 19 mm width or less ×: Less than 0.8 N / 19 mm width or more than 4.5 N / 19 mm width

[0028] [End Peeling] A protective tape for a wire harness was wrapped around a bundle of electric wires gathered to a diameter of 10 mm, and then left at 80°C for 4 hours. Thereafter, peeling at the end of the tape was checked. ○: Peeling of less than 1 mm was observed. ×: Peeling of 1 mm or more was observed.

[0029] [Abrasion Resistance] Two test pieces (protective tape for wire harnesses) of appropriate length were attached to a φ10 mm aluminum pipe, overlapping each other (double layer), and set in an abrasion resistance tester specified in JASO D 608. A load of 4.4 N was applied to the test piece. The abrasion tape was then moved at a speed of 1500 mm / min, and the tape length until the aluminum pipe and the tape came into contact was read. ◎: 450 mm or more ○: 300 mm or more but less than 450 mm ×: Less than 300 mm

[0030]

[0031] 10: Wire harness protection tape 102: Base material 104: Adhesive layer

Claims

1. A wire harness protection tape comprising a substrate and an adhesive layer formed on the substrate, wherein the substrate contains a thermoplastic resin and has a thickness of 120 μm to 190 μm, a 10% modulus (N / 19 mm width) of 12.5 to 18.5, and an unwound adhesive strength (N / 19 mm width) of 0.8 to 4.

5.

2. The wire harness protection tape according to claim 1, wherein the thermoplastic resin is at least one selected from the group consisting of polyvinyl chloride, polypropylene, and polyethylene.

3. The wire harness protection tape according to claim 1 or 2, wherein the adhesive layer contains at least one material selected from the group consisting of unmodified natural rubber latex, acrylic-modified natural rubber latex, and acrylic polymers.

4. The wire harness protection tape according to claim 1 or 2, wherein the adhesive layer has a thickness of 5 μm or more and 50 μm or less.

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