JPH0794032A - Flat cable - Google Patents

Abstract

PURPOSE:To provide a flat cable displaying an excellent cable function wherein the separation of an insulating film is eliminated to keep insulation performance for a long time even folded under high temperature or a high-humidity environment. CONSTITUTION:A conductor 1 thereon a wiring pattern is formed is sandwichedly coated by insulating films 3a and 3b via an adhesive layer 2. Both the films 3a and 3b are extended in a width direction from an outside end edge in the width direction of the conductor l to be narrowed so that an angle theta formed by both the films 3a and 3b is to be 5-25, and the width (w) of the part keeping the angle theta is 0.5-3.0mm. Both the films 3a and 3b are moreover extended in the width direction from the portion keeping the angle thetato form an ear part 31 in a portion where at least the folding of them is intended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat cable, and more particularly to a flat cable having a structure in which an insulating film does not peel off even when it is bent and used.

[0002]

2. Description of the Related Art Conventionally, in electric wire mounting technology, a flat cable in which a conductor having a flat cross section is covered with an insulating film such as a synthetic resin from both sides in a sandwich shape has been widely used for efficient wiring work. ing. For example, (1)
Electric wires for undercarpets that arrange electric wires under the carpet so that the wiring that connects each electric device in the building is not exposed on the floor, (2) For devices used as internal wiring for electronic and electric devices such as OA equipment It is used as an electric wire or (3) an electric wire that electrically connects an operation unit of a driver's seat of an automobile and various electric devices.

Since such a flat cable is lightweight and easy to install, it is particularly useful in the automobile industry.
Its application is being studied to improve the efficiency of wiring work and reduce the weight of the vehicle body.

[0004]

The above-mentioned conventional flat cable, when used in the above-mentioned applications,
It is not directly immersed in water, oil or chemicals, nor is it exposed to a high temperature and high humidity atmosphere for a long time, and there is usually no particular problem. However, in order to efficiently perform wiring in a narrow place such as a car door, for example, as shown in FIG.
As shown in FIG. 3, the flat cable may be bent 180 ° and used, but in such a case, the following problems occur.

That is, residual stress remains in the bent portion of the flat cable, and the adhesive between the conductor and the insulating film flows due to the residual stress and the heat during use.
A part where no adhesive is present is formed, and the adhesive force between the conductor and the insulating film is reduced, and as a result, these may peel off to form a void. When the flat cable is arranged in a high humidity atmosphere such as inside a door, water drops are generated due to a temperature difference between day and night, and the water drops are trapped in the void. Further, when the insulation film of the flat cable is peeled off at the edge portion due to the residual stress and heat due to the bending,
Water and water in a high-humidity atmosphere directly enter the flat cable from the peeled portion.

If the flat cable is repeatedly energized under such a condition, the electric insulation performance of the flat cable may be significantly reduced, or a short circuit may occur, resulting in loss of the flat cable function. is there.

The object of the present invention is to solve the above problems, to prevent the insulation film from peeling off even when used by bending in a high temperature or high humidity atmosphere, and to maintain the insulation performance for a long period of time and to provide an excellent cable. It is to provide a flat cable that demonstrates its function.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, in which a conductor having a wiring pattern is covered with an insulating film in a sandwich form via an adhesive layer. The coating is narrowed so as to extend in the width direction from the outer edge of the conductor in the width direction, and the angle formed by both coatings is 5 to 25 °, and the portion holding the angle has a width of 0.5. A flat cable having a thickness of up to 3.0 mm, and at least a portion where both films are intended to be bent, further extends in the width direction from a portion holding the above angle to form an ear portion. To do.

The present invention will be described below more specifically with reference to the drawings. FIG. 1 is a partial perspective sectional view showing an embodiment of the flat cable of the present invention. In the figure, F is a flat cable, in which the conductor 1 is covered with the insulating layers 3a and 3b via the adhesive layer 2 in a sandwich shape,
The coatings 3a and 3b are extended in the width direction from the outer edge of the conductor 1 in the width direction, and are narrowed so that the coatings 3a and 3b form a specific angle θ.
Part of the insulating coatings 3a and 3b further extends in the width direction from the portion holding the angle θ to form the ear portion 31.

The ear portion 31 is a portion having a function of suppressing peeling of the insulating film 3 even when the flat cable F is bent and used in a high temperature or high humidity atmosphere. Generally, the width of the ear portion 31 is preferably about 3 to 10 mm. If the width of the ear portion 31 is less than 3 mm, the peeling of the film 3 is not suppressed, while if it exceeds 10 mm, the width of the flat cable F becomes unnecessarily wide, which is disadvantageous for installation in a narrow place. Is not preferable.

In the embodiment of FIG. 1, the ears 31 are
Is formed in a portion where the cable F is intended to be bent.
The length of the ear portion 31 formed in the cable F is at least 10 mm, preferably at least 20 mm, so that the ear portion 31 can be bent without impairing the function of the cable.
mm is preferable. In general, it is desirable that the flat cable F has the ears formed over the entire length, because it is possible to bend the cable F at any portion without impairing the function of the cable. When the position is specified in advance, the ear portion may be formed only at the bending position, which is advantageous in arranging in a narrow place.

The insulating coatings 3a and 3b are extended in the width direction from the positions of the outer edges in the width direction of the conductors 1a and 1c located at the side ends of the conductor 1 so as to form an angle θ. However, in the present invention, this angle (hereinafter referred to as taper angle) θ and the width of the portion holding the angle θ (hereinafter referred to as taper portion width) w are in the following specific range. It is set within. That is, the taper angle θ is 5 to 25 °, preferably 10 to 23 °, more preferably 15 to 20 °, and the taper portion width is 0.5 to 3.0 m.
m, preferably 0.6 to 2.0 mm, more preferably 0.
It is set to 7 to 1.0 mm.

If the taper angle θ is less than the above range or the taper width w exceeds the above range, the width of the flat cable F becomes unnecessarily wide, which is disadvantageous in installing in a narrow space. If the taper angle θ exceeds the above range or the taper portion width w falls below the above range, the effect of the ear portion 31 for suppressing the peeling of the insulating film 3 becomes insufficient, which is not preferable.

Bare copper, tin-plated copper, or silver can be used as the conductor 1, and a foil-shaped or rectangular-shaped conductor is used to form a straight line, a curved line, or a combination thereof to form a wiring pattern.

As the insulating film 3, the electric insulation, heat resistance and tensile strength required for a flat cable,
Further, those having water resistance are preferable. As such an insulating film, polyolefin such as polyethylene and polypropylene, polyester, polyimide, aramid,
Polyanolate, polybutylene, terephthalate, polyphenyl sulfide, polyether sulfone, polyether ether ketone, polyether imide and the like are formed by a known method to a thickness of 12 to 200 μm, preferably 25 to 100.
A film having a thickness of μm is exemplified.

As the adhesive layer 2, it is desirable to use an adhesive having excellent adhesion to the conductor 1 and the insulating film 3, preferably an adhesive having water resistance. When this water-resistant adhesive is used, the adhesive 2 does not absorb water, absorb moisture, or hydrolyze even in the presence of water or in a high-humidity atmosphere, and the adhesion reliability between the conductor 1 and the insulating film 3 is improved. It is preferable because the property is improved. Examples of such adhesives include polyethylene resins graft-modified with unsaturated carboxylic acids and acid anhydrides, saturated copolyester resins, and the like. Further, as the water-resistant adhesive, an adhesive composed of a modified ethylene-vinyl acetate copolymer graft-copolymerized with an unsaturated carboxylic acid and an unmodified ethylene-ethyl acrylate copolymer, a dicarboxylic acid component, a diol component, and a triazine Examples thereof include an adhesive containing a polyester copolymer composed of components as a main component and a polyisocyanate compound, a saturated copolymer polyester resin, and an adhesive having three components of an organic alkoxysilane. The coating thickness of the adhesive is appropriately determined depending on the thickness of the conductor. For example, when the conductor 1 has a thickness of 100 to 150 μm, the thickness is 25 to 200 μm.
m, preferably about 30 to 150 μm.

In the present invention, a polyester-based primer and plasticized polyvinyl chloride may be used in combination instead of the above adhesive. In this case, since the conductor 1 and the insulating film 3 are adhered to each other via the primer and plasticized polyvinyl chloride, the voids in the adhesive layer are filled to improve the adhesive strength and the insulating performance. . Therefore, the durability of the flat cable is improved, the function of the cable can be exhibited for a long period of time, and the reliability is improved, which is preferable.

As a method for manufacturing the flat cable of the present invention, a conventionally known method can be used. For example, a foil-shaped conductor is placed on a synthetic resin film with an adhesive layer formed on it, half-cut to remove unnecessary conductors to form an arbitrary wiring pattern, and then on the surface of this wiring pattern. It is possible to use a method in which an adhesive layer of the same synthetic resin film as the above prepared separately is overlaid, and this is melted by heating and pasted. The two synthetic resin coatings may be bonded together as described above, but one synthetic resin coating may be folded back and bonded to each other. Since there is no problem of peeling of the insulating film at the edge and the ear portion is formed only at the other edge, the width of the flat cable can be reduced.

Further, a laminate obtained by laminating the above synthetic resin coatings is punched out to a predetermined size, and a connector is attached to the end portion to obtain a flat cable product having a desired conductor pattern.

In the above manufacturing method, a ready-made synthetic resin film was used. However, a synthetic resin film is formed by a so-called release paper method in which a synthetic resin film and a water-resistant adhesive or polyvinyl chloride are sequentially laminated on release paper. It can be formed into a film and used. Further, in the above case, when the primer layer is formed, the primer may be coated at a predetermined place.

Further, since the wiring pattern formed of the conductor is covered with the synthetic resin film through the primer layer and the plasticized polyvinyl chloride, the flexible plasticized polyvinyl chloride has a filling function to synthesize the conductor. It can be firmly adhered to the resin film without voids. Therefore, it is possible to prevent the synthetic resin film from being peeled off from the conductor and from being greatly impaired in the electric insulation performance.

[0022]

In the flat cable having the above-mentioned structure, since the ears are formed at the widthwise edges of the bent portion of the cable, even if the cable is bent and used under high temperature or high humidity atmosphere, The peeling of the insulating film is suppressed by the ears. Furthermore, by setting the angle formed by both films and the width of the part in the portion where the upper and lower insulating films are extended and narrowed within the above range, the effect of suppressing the peeling of the insulating film by the ear portion is obtained. It is further improved and the insulation performance of the flat cable is maintained for a long period of time.

[0023]

EXAMPLES Hereinafter, the present invention will be described more specifically by showing examples. Needless to say, the present invention is not limited to these examples. Example 1 (Production of flat cable) Width 520 mm, thickness 50 μm
On the polyester film (hereinafter referred to as PET film) of No. 5, an adhesive having the following composition is applied in a thickness of 50 μm to form an adhesive layer, and a copper foil having a width of 520 mm and a thickness of 100 μm is placed on the adhesive layer. After that, half-cutting was performed with a sharp blade to remove unnecessary copper foil to form a three-row wiring pattern having a width of 3 mm and a line spacing of 1 mm. Separately prepared PET film on which the same adhesive layer as above was formed was bonded to the surface of the PET film on which the wiring pattern was formed, and then punched to a length of 500 mm by pressing. As a result, a flat cable having a thickness of 0.24 mm with ears having a width of 4 mm was obtained. The taper angle of this flat cable is 18 °,
The taper width was 0.8 mm.

As the above-mentioned adhesive, modified ethylene-vinyl obtained by modifying ethylene-vinyl acetate (EVA) having a vinyl acetate (VA) content of 29% by weight and a melt flow index (MI) of 15 with acrylic acid. A mixture of an acetate copolymer (acrylic acid content: 6.1% by weight) and an unmodified ethylene-vinyl acetate copolymer having a VA content of 20% by weight and an MI of 6, wherein the unmodified ethylene-vinyl An acetate copolymer having a content of 60% by weight was used.

Examples 2 to 5 and Comparative Examples 1 to 4 Flat cables were manufactured in the same manner as in Example 1 except that the taper angle and the width of the taper portion were changed as shown in Table 1.

[0026]

[Table 1]

(Evaluation of Flat Cable) Each of the flat cables produced in the above Examples and Comparative Examples was subjected to the following folding heating test and withstand voltage test, and the results shown in Table 1 were obtained. However, in this test, 5 samples each were used. Further, the judgment was made according to the following judgment criteria.

[Bending Heating Test] As shown in the side view of FIG. 3, the center portion of the flat cable is bent 180 ° and placed in an oven and heated at 80 ° C. for 96 hours.

[Withstand Voltage Test] The flat cable that has been heated is taken out, and the bent portion is immersed in 5% saline for 30 minutes. In this state, the copper foil of the flat cable is connected to the positive electrode, and the stainless plate inserted in saline solution is connected to the negative electrode, and a DC voltage of 1000 V is applied for 1 minute between both electrodes, and the current value is measured.

[Criteria for Acceptance] (1) In the bending heating test, there should be no abnormality such as peeling of the insulating film at the bent portion. (2) No current flows in the withstanding voltage test.

As is clear from Table 1, the flat cables of the examples having the taper angle of 5 to 25 ° and the taper width of 0.5 to 3.0 mm were all bent in the bending heating test. Peeling does not occur, and water does not enter the flat cable in the withstand voltage test,
It was excellent in bendability and water resistance.

Application Example When the flat cable manufactured in Example 1 is mounted inside an automobile door, it can be installed in a limited place while bending, the work is easy, the wiring efficiency is improved, and the weight is reduced. Was achieved.

[0033]

As described above, in the flat cable of the present invention, since the ear portion is formed at the widthwise end edge of the bent portion of the cable, the flat cable is not affected under high temperature or high humidity atmosphere. Even when the cable is bent and used, peeling of the insulating film is suppressed by the ears. Furthermore, since the angle formed by both films and the width of the part in the part where the upper and lower insulating films are extended and narrowed are set within a specific range,
The effect of suppressing peeling of the insulating film by the ears is further improved. Further, as described above, peeling of the insulating film is suppressed, and since it is excellent in water resistance, a void is not formed in the flat cable and water droplets are not generated in it, or water does not directly enter from the outside. . Therefore, the electrical insulation is maintained for a long time without causing a short circuit. Further, since it can be bent and used, it is possible to effectively perform wiring within a limited area, simplify the wiring work, and improve the work efficiency. Therefore, it can be used in a place where it comes into contact with water or is exposed to a high temperature and high humidity atmosphere, especially inside a door of an automobile, and the excellent function of the flat cable is maintained for a long period of time. Further, since the weight is reduced, its application can be further expanded.

[Brief description of drawings]

FIG. 1 is a partial perspective sectional view of a flat cable showing an embodiment of the present invention.

FIG. 2 is a side view showing a state in which a flat cable is bent.

[Explanation of symbols]

 1 conductor 2 adhesive 3 insulating film 31 ear F flat cable

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Furukawa 8 Nishinocho, Higashimukaijima, Amagasaki City, Hyogo Prefecture Mitsubishi Electric Wire & Cable Co., Ltd.

Claims (1)

[Claims] 1. A conductor on which a wiring pattern is formed is covered in a sandwich shape with an insulating film via an adhesive layer, and both films are extended in the width direction from the outer edge in the width direction of the conductor. And the angle between both coatings is narrowed to 5 to 25 °, and the width of the portion that holds the angle is 0.5 to
A flat cable having a thickness of 3.0 mm, and at least the portions intended to be bent, the ears are formed by further extending in the width direction from the portion holding the above angle.