KR20190074705A - Flexible flat cable conductor, method for producing copper foil and flexible flat cable using the same - Google Patents

Abstract

The present invention relates to a flexible flat cable conductor having improved bending properties, a manufacturing method thereof, and a flexible flat cable using the same. The flexible flat cable conductor according to an embodiment of the present invention is a conductor applied to a flexible flat cable, and includes 0.05 to 0.1 wt% of silver (Ag), 0.015 to 0.05 wt% of oxygen (O), remaining copper (Cu) and unavoidable impurities.

Description

TECHNICAL FIELD [0001] The present invention relates to a flexible flat cable conductor, a method of manufacturing the same, and a flexible flat cable using the same. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a flexible flat cable conductor,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible flat cable conductor, a method of manufacturing the same, and a flexible flat cable using the same. More particularly, the present invention relates to a flexible flat cable conductor having improved bending properties, a method of manufacturing the same, and a flexible flat cable using the same.

A flexible flat cable (hereinafter referred to as an FFC) for a steering roll connector (SRC) is used to transmit various signals by means of a conductor disposed inside thereof while reciprocating at a small bending radius. do.

These FFCs are formed in such a manner that the insulating film covers a plurality of conductors used as a medium for signal transmission. In the FFC, the conductor and the insulating film are laminated by means of an adhesive, and are formed into a flat shape. In this case, conductors such as C1100 (tarpauline copper) and C1020 (oxygen free copper) are mainly used as the conductor, and fluorine resin, polyimide resin, PET resin, epoxy resin and the like are used as the insulating film. As the adhesive for bonding the insulating film and the conductor, a material in which PVB (polyvinyl butyral) and a resin such as a resol type phenol, melamine, and epoxy are added is used.

FFC, which is made of such a flexible material, is repeatedly reciprocated at a small radius of curvature. When stress is accumulated in the copper foil as a conductor, cracks or disconnection are generated, which affects the service life. If a large damage is applied to the copper foil disposed inside the FFC during the reciprocating movement of the FFC, there may arise a problem that the conductor is broken and the signal is not transmitted.

Japanese Patent Application Laid-Open No. 2000-067641 (Mar. 3, 2000) Korean Patent Publication No. 10-20160011041 (2016.01.29)

The present invention relates to a flexible flat cable conductor capable of improving flexural durability by adjusting an alloy element of a conductor used in an FFC and raising a recrystallization temperature to coarsen crystal grains under specific process conditions during rolling and a manufacturing method thereof, Cable.

A flexible flat cable conductor according to an embodiment of the present invention is a conductor applied to a flexible flat cable, and includes 0.05 to 0.1 wt% of silver (Ag), 0.015 to 0.05 wt% of oxygen (O) Includes unavoidable impurities.

The conductor is characterized in that the size of the crystal grain is 3 mu m or more.

The conductor has an elongation of 5% or less.

Meanwhile, a method of manufacturing a flexible flat cable conductor according to an embodiment of the present invention is a method of manufacturing a conductor applicable to a flexible flat cable, which comprises 0.05 to 0.1 wt% of silver (Ag) wt%, remaining copper (Cu) and unavoidable impurities; Drawing the prepared molten steel into a wire rod; First rolling the wire rod to 70-80% of the final target thickness; Subjecting the first rolled rolled material to a first heat treatment; Secondarily rolling the first heat treated rolled material to a final target thickness; And subjecting the second rolled rolled material to a secondary heat treatment.

The rolling material subjected to primary rolling in the primary rolling step is not recrystallized, and the secondary rolling material is recrystallized in the secondary rolling step.

In the first heat treatment step, the heat treatment current is controlled to be 16 A or more and the heat treatment voltage is controlled to 5 V or more. In the second heat treatment step, the heat treatment current is adjusted to 12.0 to 12.4 A and the heat treatment voltage is controlled to 7.0 to 8.0 V do.

In the second heat treatment step, the rolled material is heat-treated so that the size of the grain is 3 m or more.

And the rolled material after the second heat treatment step has an elongation of 5% or less.

The flexible flat cable according to an embodiment of the present invention includes 0.05 to 0.1 wt% of silver (Ag), 0.015 to 0.05 wt% of oxygen (O), the balance of copper (Cu) and unavoidable impurities, At least one conductor having a size of 3 mu m or more and an elongation of 5% or less; And an insulating film covering the at least one conductor.

The conductor has a width of 0.1 to 2.0 mm, a thickness of 0.015 to 0.050 mm, and a plurality of the conductors are spaced apart from each other and arranged on the same plane.

According to the embodiment of the present invention, it is possible to coarsen crystal grains during rolling and heat treatment as the recrystallization temperature of the conductor is increased by mixing an appropriate amount of silver into the copper foil used as the conductor used in the FFC, so that the flexible flat cable An effect of manufacturing a conductor can be expected.

1 is a view showing a flexible flat cable according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

1 is a view showing a flexible flat cable according to an embodiment of the present invention.

As shown in the drawing, the flexible flat cable 1 according to an embodiment of the present invention includes at least one conductor 10 that is rolled and formed in a flat shape, Film (20). At this time, the conductor 10 and the insulating film 20, which are spaced apart from each other and arranged on the same plane, are laminated via the adhesive 30 to have a flat shape.

Here, the insulating film 20 is made of a fluororesin, a polyimide resin, a PET resin, an epoxy resin, or the like, and the adhesive 30 is formed by adding a resin such as PVB (polyvinyl butyral) and a resol type phenol, melamine, One material may be used. Of course, the insulating film 20 and the adhesive 30 are not limited to the illustrated embodiments, but various materials that can be implemented to perform the functions may be used.

On the other hand, the conductor 10 is a means used for reciprocating in a small radius of curvature and transmitting various electrical signals by conductors disposed therein. The conductor 10 includes C1100 (tarpaulgi copper), C1020 And the flexural endurance characteristics were improved.

In this embodiment, in order to improve the bending durability characteristics, the crystal grains are coarsened under the rolling and heat treatment conditions under specific conditions in the manufacturing process through adjustment of alloy components.

The flexible flat cable conductor 10 according to an embodiment of the present invention includes 0.05 to 0.1 wt% of silver (Ag), 0.015 to 0.05 wt% of oxygen (O), the balance of copper (Cu) and unavoidable impurities.

The reason why silver (Ag) is added at a level of 0.05 to 0.1 wt% without using almost pure copper such as the conventional C1100 (tarpaulgi copper) and C1020 (oxygen free copper) is that the addition of silver , The temperature of the recrystallization of the conductor is increased while suppressing the decrease of the conductivity.

When silver (Ag) is added to copper (Cu), a solid solution is formed. As a result, atomic mobility is lowered, thereby improving the heat resistance and recrystallization temperature. Therefore, at least silver (Ag) is preferably added in an amount of 0.05 wt% or more for raising the recrystallization temperature of the conductor. However, the recrystallization temperature of a conductor, which is a copper (Cu) alloy, saturates near 0.1 wt% of silver (Ag). Also, the more the amount of silver (Ag) added, the lower the electric conductivity, but the decrease in conductivity is hardly observed when the content of silver (Ag) is 0.1 wt%. Therefore, it is preferable to limit the maximum value of the silver (Ag) content to 0.1 wt%.

On the other hand, since oxygen (O) reacts with silver (Ag) to form silver oxide, it is preferable to limit the oxygen content in the conductor to 0.015 to 0.05 wt%.

It is preferable that the conductor 10 having such a composition has a grain size of 3 mu m or more.

In addition, it is preferable that the elongation of the conductor 10 is 5% or less.

Next, a method of manufacturing a flexible flat cable conductor having the above composition will be described.

A method of manufacturing a flexible flat cable conductor according to an embodiment of the present invention includes preparing a molten steel having the above composition, and then subjecting the prepared molten steel to a wire rolling process.

In other words, a molten steel containing 0.05 to 0.1 wt% of silver (Ag), 0.015 to 0.05 wt% of oxygen (O), the remaining copper (Cu) and unavoidable impurities is prepared.

When the molten steel is prepared, the prepared molten steel is drawn into the wire rod. At this time, the wire rod is drawn to a diameter of 2 mm, and then is drawn to a diameter of 0.3 to 0.7 mm through a drawing machine.

The fresh wire is first rolled to 70 to 80% of the final target thickness. During the primary rolling, recrystallization does not occur due to the increased recrystallization temperature due to the addition of silver (Ag).

The rolled material subjected to the primary rolling is subjected to a first heat treatment at a heat treatment current of 16 A or more and a heat treatment voltage of 5 V or more.

The rolled material subjected to the first heat treatment is secondarily rolled to the final target thickness. The final target thickness to be set at the time of secondary rolling is 0.015 to 0.050 mm and the width is 0.1 to 2.0 mm. On the other hand, because of the recrystallization temperature increased by the addition of silver (Ag), recrystallization is not performed at the time of primary rolling but recrystallization is performed at the time of secondary rolling.

The rolled material subjected to recrystallization during the secondary rolling is subjected to a secondary heat treatment at a heat treatment current of 12.0 to 12.4 A and a heat treatment voltage of 7.0 to 8.0 V. In the rolling material recrystallized during the secondary rolling, the crystal grains are coarsened during the secondary heat treatment, and the residual stress is removed inside the conductor.

Therefore, it is preferable that the thickness of the conductor is from 0.015 to 0.050 mm, the width is from 0.1 to 2.0 mm, the grain size is at least 3 mu m, and the elongation is at most 5% at the end of the secondary heat treatment.

Hereinafter, the present invention will be described using Examples and Comparative Examples.

The wire rod was drawn out of molten steel having the alloy composition according to the present invention, and then subjected to primary rolling, primary heat treatment, secondary rolling and secondary heat treatment. At this time, the first target rolling and the second rolling were performed under the same conditions with the final target thickness set at 0.03 mm. However, the first heat treatment and the second heat treatment were carried out while changing the conditions as shown in Table 1 below, and the grain size and elongation rate thereof were measured and are shown in Table 1. However, the voltage was fixed at 5V during the first heat treatment, and the voltage was fixed at 7V during the second heat treatment.

division Primary heat treatment (A) Second heat treatment (A) Grain size (탆) Elongation (%) No. One 15.2 X 0.8 X No. 2 15.7 X 1.3 X No. 3 16.1 X 2.2 X No. 4 15.2 12 1.3 1-3 No. 5 15.2 12.5 1.7 21 ~ 25 No. 6 15.7 12.5 2.3 18-23 No. 7 16.1 12.2 3.6 1-2 No. 8 16.1 12.5 3.9 22-26

As can be seen from Table 1, when the first heat treatment current is higher than 16 A and the second heat treatment current is higher than 12.0 to 12.4. 7 satisfied the condition that the size of the crystal grains was 3 mu m or more and the elongation was 5% or less.

On the other hand, in order to investigate the difference in grain size, elongation and durability due to the change of the material and the change of the heat treatment process, experiments were performed to measure the grain size, elongation and durability while changing the conditions as shown in Table 2 below. Are shown together in Table 2.

division Material Contents Elongation Grain size Endurance test No. 11 C1100 Incomplete heat treatment 1.2% Sub μm 200,000 times No. 12 0.1% Ag + C1100 Primary heat treatment (16.1A) → Second heat treatment (12.2A) 1.4%
3.6 μm 570,000 times No. 13 0.1% Ag + C1100 Primary heat treatment (16.1A) → Second heat treatment (12.5A) 26.6% 3.9 μm 260,000 times No. 14 C1100 Primary heat treatment (17.0A) → Second heat treatment (12.0A) 16% 4.1 μm 250,000 times

As can be seen from Table 2, the first annealing current was 16 A or more and the second annealing current was 12.0 to 12.4, while containing 0.05 to 0.1 wt% of silver (Ag). 12 satisfied the condition that the size of the crystal grains was 3 mu m or more and the elongation was 5% or less. The durability test was also carried out on 570,000 cycles. 11 showed good results in the endurance test.

And, No. 13 samples satisfied the alloy component but did not satisfy the secondary heat treatment condition and the grain size satisfied 3 탆 or more. However, it was confirmed that the elongation was considerably increased. 12 samples. ≪ tb > < TABLE >

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

1: Flexible flat cable (FFC)
10: Conductor
20: Insulation film
30: Adhesive

Claims (10)

As a conductor applied to a flexible flat cable,
0.05 to 0.1 wt% of silver (Ag), 0.015 to 0.05 wt% of oxygen (O), the balance of copper (Cu) and unavoidable impurities.
The method according to claim 1,
Wherein the conductor has a grain size of 3 m or more.
The method according to claim 1,
Wherein the conductor has an elongation of 5% or less.
A method of manufacturing a conductor applied to a flexible flat cable,
Preparing molten steel containing 0.05 to 0.1 wt% of silver (Ag), 0.015 to 0.05 wt% of oxygen (O), remaining copper (Cu), and unavoidable impurities;
Drawing the prepared molten steel into a wire rod;
First rolling the wire rod to 70-80% of the final target thickness;
Subjecting the first rolled rolled material to a first heat treatment;
Secondarily rolling the first heat treated rolled material to a final target thickness;
And subjecting the second rolled rolled material to a secondary heat treatment.
The method of claim 4,
In the primary rolling step, the primary rolled material does not undergo recrystallization,
Wherein the second rolled rolled material is recrystallized in the second rolling step.
The method of claim 5,
In the primary heat treatment step, the heat treatment current is controlled to be 16 A or more and the heat treatment voltage is controlled to be 5 V or more,
Wherein the heat treatment current is adjusted to 12.0 to 12.4 A and the heat treatment voltage to 7.0 to 8.0 V in the secondary heat treatment step.
The method of claim 6,
Wherein in the second heat treatment step, the rolled material is heat-treated to have a grain size of 3 mu m or more.
The method of claim 7,
Wherein the rolling material after the secondary heat treatment step has an elongation of 5% or less.
At least one layer containing at least 0.05% by weight of silver (Ag): 0.05 to 0.1% by weight of oxygen (O): 0.015 to 0.05% by weight and balance copper and unavoidable impurities, Or more conductors;
And an insulating film covering said at least one conductor.
The method of claim 9,
Wherein the conductor has a width of 0.1 to 2.0 mm, a thickness of 0.015 to 0.050 mm, and a plurality of spaced apart conductors arranged on the same plane.

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