JP2005112894A - Binding tape for electric wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the heat resistance of a tape for binding electric wires having a non-halogenous insulating material and used in the engine room periphery of a vehicle; specifically to provide a binding tape for electric wires capable of preventing the occurrence of cracks on the surface of the electric wires bound by the binding tape. <P>SOLUTION: The binding tape for electric wires is composed of a substrate and a pressure-sensitive adhesive layer formed on the surface thereof. The pressure-sensitive adhesive layer comprises a mixture of a natural rubber-derived pressure-sensitive adhesive and an SBR-derived pressure-sensitive adhesive, a hydrogenated tackifier, and an antioxidant. The substrate is a film formed from an olefin resin composition or is selected from nonwoven fabrics and woven fabrics. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tape for binding electric wires having non-halogenous insulators used in automobiles and the like. More specifically, the present invention relates to a heat-resisting electric wire binding tape made of a rubber adhesive or the like. Units such as “parts” indicating the blend composition of the electric wire binding tape of the present invention are expressed on a mass basis unless otherwise specified.

  Electric wires used in the surroundings of engine rooms such as automobiles have high withstand voltage and insulation resistance, and are excellent in flame retardancy alone. Therefore, electric wires that have been made of polyvinyl chloride resin composition (halide) as an insulator. Is often used. However, when an electric wire using such a vinyl chloride resin composition is burned, corrosive hydrogen chloride gas is generated from the vinyl chloride resin composition. Therefore, in recent years, attempts have been made to use a polyolefin resin composition such as polyethylene which does not contain a halide as an insulator for automobile electric wires. A natural rubber adhesive or SBR (styrene butadiene rubber) adhesive, which is a general rubber adhesive, is used as a tape for binding electric wires mainly composed of a polyolefin resin composition. However, since the rubber-based pressure-sensitive adhesive has an unsaturated double bond in the rubber molecule, it easily deteriorates in the presence of oxygen or light. Therefore, the tape for bundling the wires may not have sufficient heat resistance and may cause cracks on the surface of the wires.

  As an electric wire binding tape having a high degree of heat resistance, an electric wire binding tape in which an adhesive layer is provided on a substrate surface made of an inorganic flame retardant and a polyolefin resin composition is known (for example, see Patent Document 1).

Further, the durability of the vehicle is required to have long-term reliability, and the reliability is also required for the electric wire binding tape disposed around the engine room of the vehicle. As non-halogenation of the electric wire proceeds, higher heat resistance is required. Specifically, when a heat resistance test of 80 ° C. × 10,000 hours is performed in a state where the electric wire binding tape is wound around the electric wire, it is required that no crack is generated on the surface of the electric wire. When the heat resistance test is required, a polyolefin resin composition having excellent flame retardancy or a combination of an inorganic flame retardant and a polyolefin resin composition is insufficient for the base material of the cable-binding tape.
Japanese Patent Laid-Open No. 7-18225

  The present invention solves the conventional drawbacks and improves the heat resistance of a binding tape for electric wires for binding electric wires (hereinafter referred to as “electric wires”) made of non-halogenated materials used in the vicinity of a vehicle engine room. Make it. Specifically, an object of the present invention is to provide an electric wire binding tape that can prevent the occurrence of cracks on the surface of the electric wire bound by the electric wire binding tape.

As a result of intensive studies in view of the above, the present inventors have found that cracks on the surface of the electric wire are generated when oxygen is applied to the pressure-sensitive adhesive layer and the pressure-sensitive adhesive or tackifier is oxidized to generate oxygen radicals and carbon radicals. As a result, the present inventors have found out that there is a cause, and found that the above problems can be solved by imparting heat resistance while devising not to generate the radical.

That is, the present invention comprises a base material and a pressure-sensitive adhesive layer formed on the surface thereof, and the pressure-sensitive adhesive layer is hydrogenated with respect to 100 parts of a mixture of a natural rubber pressure-sensitive adhesive and an SBR pressure-sensitive adhesive. It is an electric wire binding tape formed by blending 5 to 200 parts and an anti-aging agent 0.3 to 10 parts.

According to a second aspect of the present invention, there is provided the electric wire binding tape according to claim 1, wherein the base material is a film or cloth made of a polyolefin resin composition.

  Since the binding tape for electric wires according to the present invention is excellent in heat resistance, by binding the electric wire having a non-halogenous insulator used around the engine room of the vehicle with the binding tape for electric wires, Generation of cracks can be prevented.

  The rubber-based adhesive that can be used for the adhesive layer of the electric wire binding tape according to the present invention uses a mixture of a natural rubber-based adhesive and an SBR-based adhesive.

The tackifier of the present invention can be used for improving the adhesive strength of the wire binding tape and preventing the occurrence of cracks on the surface of the electric wire.

  Examples of the hydrogenated tackifier that can be used in the present invention include hydrogenated terpene phenol (softening point 85-125 ° C.), aromatic hydrogenated resin (softening point 100 ° C.), aliphatic hydrogenated resin ( Examples thereof include a single substance or a mixture such as a softening point of 92 to 120 ° C. and a coumarone indene resin (softening point of 100 ° C.). Since a heat resistance test of 80 ° C. × 10,000 hours is required, it is desirable that the hydrogenated tackifier has a softening point of 80 ° C. or higher.

  The compounding amount of the hydrogenated tackifier is in the range of 5 to 200 parts with respect to 100 parts of the rubber-based adhesive. When the tackifier is less than 5 parts, there is peeling of the wire binding tape from the electric wire due to insufficient adhesive force. On the other hand, when the tackifier exceeds 200 parts, the adhesive sticks out and heat resistance cannot be obtained.

  The anti-aging agent of the present invention is used to improve the pressure-sensitive adhesive because it has an unsaturated double bond in the rubber molecule and is therefore likely to deteriorate in the presence of oxygen or light.

  Anti-aging agents that can be used in the present invention include phenol-based anti-aging agents, amine-based anti-aging agents, benzimidazole-based anti-aging agents, dithiocarbamate anti-aging agents, phosphorus-based anti-aging agents, etc. alone or Mention may be made of mixtures.

  The amount of the anti-aging agent is in the range of 0.3 to 10 parts with respect to 100 parts of the rubber-based pressure-sensitive adhesive. When the anti-aging agent is less than 0.3 part, the occurrence of cracks on the surface of the wire due to oxidative degradation occurs. On the other hand, if the anti-aging agent exceeds 10 parts, bleeding occurs and adhesive strength is reduced.

  A crosslinking agent, a softening agent, a filler, a flame retardant, and the like can be added to the rubber-based pressure-sensitive adhesive as necessary. Specific examples include isocyanate crosslinking agents as crosslinking agents, liquid rubber as softening agents, calcium carbonate as fillers, and inorganic flame retardants such as magnesium hydroxide and red phosphorus as flame retardants.

  For the base material of the cable-binding tape according to the present invention, any film or cloth made of a polyolefin (hereinafter abbreviated as “PO”) resin composition can be employed. As the cloth, for example, a nonwoven fabric or a woven cloth can be used.

  As the PO-based resin, conventionally known resins can be appropriately selected and used. For example, high-density polyethylene, medium-density polyethylene, ultra-low-density polyethylene, high-pressure method low-density polyethylene, linear low-density polyethylene, ethylene-propylene Olefin rubber such as copolymer rubber, ethylene-propylene-diene copolymer rubber, ethylene-butene-1 copolymer rubber, ethylene-vinyl ester copolymer such as ethylene-vinyl acetate copolymer, ethylene-ethyl- Ethylene-based (co) polymers such as acrylate copolymers, ethylene- (meth) acrylic acid alkyl ester ester copolymers, and other ethylene-α, β-carboxylic acids or copolymers thereof, polypropylene, propylene-ethylene copolymers Examples thereof include polypropylene copolymers such as polymers, and polybutene copolymers.

  The means for forming the PO resin composition into a film is not particularly limited, and examples thereof include an extrusion method, a rolling method, and a laminating method. In the film forming step, various auxiliary materials such as a solvent, a lubricant, an antifoaming agent, a filler, a plasticizer, an antioxidant, an antiblocking agent, and a separator may be used.

  The fiber constituting the nonwoven fabric or woven fabric is not particularly limited, and examples thereof include chemical fibers such as polyurethane, polypropylene, polyester, rayon and nylon, and natural fibers such as pulp and cellulose.

  The base material thickness of the electric wire binding tape is suitably 50 to 400 μm. The electric wire binding tape is required to be flexible in order to cope with an operation of winding around electric wires having various forms. This is because the flexibility is generally determined by the thickness of the base material of the binding tape for electric wires.

  The means for applying the pressure-sensitive adhesive, pressure-sensitive adhesive imparting agent, and anti-aging agent constituting the pressure-sensitive adhesive layer of the wire binding tape to the base material of the wire binding tape is not particularly limited. There is a method in which a pressure-sensitive adhesive solution composed of an agent, a pressure-sensitive adhesive imparting agent and an anti-aging agent is applied to one side of the substrate by a transfer method and dried. Although the thickness of an adhesive layer can be suitably selected in the range which does not impair adhesiveness and handleability, 5-40 micrometers is preferable normally. More preferably, it is 10-30 micrometers. If it is 5 μm or less, the adhesive strength may be lowered, and if it exceeds 40 μm, the coating performance is deteriorated.

  Hereinafter, Example 1 according to the present invention will be described in more detail with reference to Table 1 and in comparison with Comparative Examples. In Table 1, the value of the pressure-sensitive adhesive is shown as a value when the mixture of the natural rubber-based pressure-sensitive adhesive and the SBR-based pressure-sensitive adhesive is 100 parts. A tackifier and an anti-aging agent are compounding ratio with respect to 100 parts of said adhesives.

(Evaluation methods)
The following evaluations were performed on the electric wire binding tapes prepared in Examples and Comparative Examples, and the results are summarized in Table 1.
For the “crack”, a test method generally used by vehicle electrical equipment manufacturers was adopted. That is, after a wire having a non-halogenous insulator used around the engine room of a vehicle or the like is bound with a wire binding tape and left in an oven at 80 ° C. for 10,000 hours, the surface of the wire is cracked. This is a method of visually observing whether or not this occurs. The case where no crack was generated was evaluated as good (◯), and the case where a crack was generated was determined as poor (x).

  The “adhesive strength” was a 25 mm-wide wire bundling tape attached as a test piece to a SUS plate as an adherend under conditions of 23 ± 2 ° C. and 65 ± 5% RH. The sticking was performed by reciprocating the test piece once with a rubber roller having a weight of 2 kg. After 20 minutes from pasting, the strength when one end of the test piece was peeled off from the SUS plate at a speed of 300 mm / min in the direction of 180 degrees was measured, and the strength was 1N / 10 mm or more. And those having a strength of 1 N / 10 mm or less were defined as defective (x).

  “Bleed” is the deposition of antioxidants and their reactants on the adhesive surface of the wire binding tape. Those that did not precipitate were evaluated as good (◯), and those that precipitated were determined as poor (×).

“Appearance” shows the result of visually checking the familiarity of the electric wire binding tape of the electric wire after 24 hours by wrapping the electric wire binding tape around the electric wire. The case where the adhesive did not protrude from the side surface of the wire binding tape was judged as good (◯), and the case where the adhesive was sticking out was judged as poor (x).

In addition, “Comprehensive evaluation” in Table 1 indicates that all characteristic values are good (◯) as appropriate (◯), and any one of the characteristic values is defective (×) is inappropriate. (X).

  (Embodiment 1) A wire binding tape in this embodiment is a base material made of a PO resin, 100 parts of a rubber adhesive made of a mixture of natural rubber and SBR as an adhesive, and a hydrogenated terpene as a tackifier Resin is blended with 80 parts of Clearon P from Yasuhara Chemical Co., Ltd. and 4 parts of irganox 1520D from Ciba-Geigy Co., Ltd., and contains a small amount of stabilizer, lubricant and colorant. It is kneaded with a mixer and formed to a thickness of 100 μm by calendering.

  (Comparative Examples 1 to 4) A wire-binding tape was prepared in the same manner as in Example 1 except that the blending amounts of the pressure-sensitive adhesive and the antioxidant were changed to the values shown in Table 1.

  Comparing Comparative Example 1, Example 1 and Comparative Example 2 (the blended amounts of hydrogenated terpene resin 3, 80 and 210) in which the blending amount of the tackifier was changed, the amount of the hydrogenated terpene resin was too small. When the amount of the hydrogenated terpene resin was too large, the pressure-sensitive adhesive protruded from the wire binding tape, and the appearance deteriorated.

Comparing Comparative Example 3, Example 1 and Comparative Example 4 in which the blending amount of the anti-aging agent was changed (blending amounts 0.1, 4 and 12 of the anti-aging agent)
When the amount of the anti-aging agent was too small, cracks occurred on the surface of the electric wire, and when the amount of the anti-aging agent was too large, bleeding occurred.

  Since the binding tape for electric wires of Comparative Example 1 had too little tackifier, no adhesive force was obtained. The binding tape for electric wires of Comparative Example 2 had a poor appearance because there were too many tackifiers. Since the binding tape for electric wires of Comparative Example 3 contained too little anti-aging agent, the surface of the electric wires had cracks. Since the binding tape for electric wires of Comparative Example 4 contained too much anti-aging agent, no adhesive force was obtained, and cracks were generated on the surface of the electric wires.

As an application example of the present invention, as a tape for binding an electric wire having a non-halogenous insulator used around a vehicle engine room under a high temperature condition, the surface of the electric wire has cracks because of excellent heat resistance. There is no outbreak, and it can be used industrially.

Claims (2)

It consists of a base material and a pressure-sensitive adhesive layer formed on the surface thereof, and the pressure-sensitive adhesive layer is 5 to 200 parts of hydrogenated tackifier with respect to 100 parts of a mixture of a natural rubber-based adhesive and an SBR-based adhesive, and A binding tape for electric wires formed by blending 0.3 to 10 parts of an anti-aging agent. The binding tape for electric wires according to claim 1, wherein the substrate is a film or cloth made of a polyolefin resin composition.