JP6809957B2 - A flat cable, a rotary connector device including the flat cable, and a method for manufacturing the flat cable. - Google Patents

Description

The present invention relates to a flat cable, a rotary connector device including a flat cable, and a method for manufacturing a flat cable, and more particularly to a flexible flat cable which is arranged in a rotary connector device for a vehicle and has excellent bending characteristics and manufacturability.

Conventionally, in a vehicle such as a four-wheeled vehicle, a rotary connector device (SRC) for supplying power to an airbag device or the like is attached to a connecting portion between a steering wheel for steering and a steering shaft. The rotary connector device includes a stator, a rotator rotatably assembled to the stator, and a flexible flat cable (FFC) wound and housed in an annular internal space formed by the stator and the rotator. At the end of the FFC, a connection structure for electrically connecting the FFC and the outside is provided.

The FFC includes a plurality of conductors arranged in parallel, a pair of insulating sheets arranged so as to sandwich the plurality of conductors, and an adhesive layer provided between the pair of insulating sheets. It has a laminated structure composed of a conductor, a pair of insulating sheets, and an adhesive layer. The conductor is made of, for example, tough pitch copper, oxygen-free copper, or the like. Further, the insulating sheet has an adhesive layer made of polyester-based, polyurethane-based, polyamide-based, or polystyrene-based resin, and the pair of insulating sheets are passed through the adhesive layer in a state where a plurality of conductors are sandwiched. By adhering them together, the conductors or the conductors and the outside are insulated from each other.

Examples of the conductor include a copper alloy obtained by adding 0.3 wt% or less of Sn and 0.3 wt% or less of In or Mg to oxygen-free copper, or copper obtained by adding 10 wt% or less of Ag to oxygen-free copper. A flat conductor having an alloy as a base material and a flat conductor whose surface is plated with Sn is heat-treated to have a tensile strength of 350 MPa or more, an elongation of 5% or more, and a conductivity of 70% IACS or more (patented patent). Document 1). Further, in pure copper such as tough pitch copper and oxygen-free copper, the bending characteristics are improved by increasing the X-ray diffraction intensity of the (200) plane of the rolled surface, and by highly developing the Cube orientation, which is synonymous in this case. Has been proposed (Patent Document 2).

Japanese Patent No. 4734695 Japanese Patent No. 309383

A highly flexible conductor in which crystal grains in the Cube orientation are highly integrated and controlled using a copper material having a high Cu purity such as oxygen-free copper as in Patent Document 2 or tough pitch copper, and a method for producing the same are already known. However, in such a manufacturing method, the conductor is recrystallized by the heat treatment during the manufacturing of the entire FFC, that is, during the laminating process or after the laminating process, and the orientation control (recrystallization texture) is completed, and the conductor is manufactured. Has a processed texture before the completion of the laminating process. At this stage, the conductor does not have sufficient flexibility.

There is a need for miniaturization of rotary connector devices, and internal flexible flat cables are required to have durability with a smaller bending radius. Hard copper and annealed copper manufactured by the general manufacturing method of pure copper typified by tough pitch copper are currently used as cable conductors for rotary connector devices, but with the need for miniaturization of devices, conductors with higher bending resistance Is required.
In addition, the width of conductors used in flexible flat cables is decreasing in order to meet the needs for miniaturization and multi-channels. Therefore, the manufacturing difficulty of flexible flat cables is increasing, and conductors that contribute to the improvement of manufacturability are required. Although a copper alloy conductor is effective for improving manufacturability, there is a problem that a copper alloy conductor has a higher electric resistance than a pure copper conductor.
Further, among the tough pitch coppers, the recrystallized material (annealed copper) having a highly integrated Cube orientation is the most excellent in flexibility, and is promising as a conductor material that can meet the needs for miniaturization in the future. However, it is known that the mechanical strength of annealed copper is lower than that of general annealed copper as the texture is formed, and the material strength is significantly reduced due to the decrease in cross-sectional area due to the narrowing of the width. It is expected that the adverse effects on sexuality will become significant.

Further, conventionally, polyethylene terephthalate (PET) and a resin provided with an adhesive layer having a lower melting point inside the polyethylene terephthalate (PET) are often used as the material of the insulating sheet of FFC, and this PET is changed to, for example, polyimide (PI). High-temperature heat treatment of the laminate to the extent that the above-mentioned Cube orientation can be highly developed becomes possible, but the cost competitiveness is greatly reduced and the product competitiveness is inferior. On the other hand, it is difficult to use a PET insulating sheet if the recrystallization treatment is performed at the time of laminating because PET causes melting that accompanies flow in the adhesive layer when the high temperature treatment corresponding to the recrystallization treatment is performed. .. In addition, if recrystallization occurs in which the Cube orientation is highly oriented during heating of the laminating process, the strength of the conductor is extremely reduced, which makes it difficult to control the laminating process, and at the time of subsequent FFC-connector joining or rotary connector device. It also causes a change in shape and breakage of the broken conductor when the FFC is housed, which reduces productivity.

An object of the present invention is a flat cable having excellent bending characteristics and a longer life than before without impairing manufacturability, productivity and conductivity, a rotary connector device provided with the flat cable, and a flat. The purpose is to provide a method for manufacturing a cable.

As a result of intensive research, the present inventor has made a conductor of hard copper capable of highly integrating the Cube orientation, which shows a long life during bending, by appropriately controlling the structure of the crystal grains in the texture of the hard copper. Used as a material, it maintains the strength of hard copper when manufacturing flat cables and rotary connectors to ensure productivity, and when the flat cable is bent, the Cube orientation grains in the conductor grow preferentially, giving higher flexibility than before. However, it was found that a longer life can be realized.

That is, the gist structure of the present invention is as follows.
(1) Rolling consisting of either tough pitch copper or oxygen-free copper and having an area ratio of crystal grains of 25% or more oriented in the direction of {123} <634> with an allowable deviation angle of 0 ° to 12.5 °. A flat cable comprising a predetermined number of conductors having a processed texture.
(2) The average value of the crystal grain dimensions in the thickness direction of the conductor is 3 μm or less, and the grain size in the width direction of the conductor is divided by the crystal grain size in the thickness direction of the conductor. The flat cable according to (1) above, wherein the average value of the values is 3 or more.
(3) The conductor is characterized in that the 0.2% proof stress is 400 MPa or more, and the 0.2% proof stress of the conductor after heat treatment at 160 to 200 ° C. and 0.1 s to 5 s is 300 MPa or more. The flat cable according to (1) or (2) above.
(4) An adhesive layer made of a material that can be melted under heating conditions of 160 to 200 ° C. and 0.1s to 5s, and a pair of insulating sheets made of a material that does not melt under the heating conditions are further provided.
The conductor according to any one of (1) to (3) above, wherein the conductor is arranged so as to be sandwiched between the pair of insulating sheets via the adhesive layer to form a laminated structure. Flat cable.
(5) The flat cable according to any one of claims 1 to 4, wherein the base layer is made of polyethylene terephthalate.
(6) As a result of performing an IPC bending test under test conditions of 50 ° C. or higher, a stroke length of 10 mm to 15 mm, and a bending speed of 10 to 500 rotations / minute, the conductor is a bent portion after a 100,000 times bending test. The flat cable according to any one of (1) to (4) above, wherein the flat cable has an texture in which the area ratio of the crystal grains oriented in the direction of {001} <100> is 75% or more.
(7) A rotary connector device including the flat cable according to any one of (1) to (5) above.
(8) A method for manufacturing a flat cable having a predetermined number of conductors made of either tough pitch copper or oxygen-free copper.
It has a heat treatment step and a final rolling step after a casting step, a hot rolling step and a cold rolling step of a material made of either tough pitch copper or oxygen-free copper.
The heat treatment conditions in the heat treatment step are 200 to 700 ° C. and 15s to 5h.
The rolling ratio in the final rolling step is 75% or more.
A method of manufacturing a flat cable, which is characterized in that.
(9) A method for manufacturing a flat cable having a predetermined number of conductors made of either tough pitch copper or oxygen-free copper.
After the casting step, hot rolling step and cold rolling step of the material consisting of tough pitch copper or oxygen-free copper, the first heat treatment step, the first rolling step, the second heat treatment step, and the final rolling step Have,
The heat treatment conditions in the first heat treatment step are 200 to 700 ° C. and 15s to 5h.
The rolling ratio in the first rolling step is 75% or less.
The heat treatment conditions in the second heat treatment step are 200 to 700 ° C. and 15s to 5h.
The rolling ratio in the final rolling step is 75% or more.
A method of manufacturing a flat cable, which is characterized in that.
(10) After the final rolling step, a predetermined number of conductors obtained in the final rolling step are melted under heating conditions of 160 to 200 ° C. and 0.1s to 5s via an adhesive that can be melted under the heating conditions. It further has a laminating process of forming a laminating structure by sandwiching it between two insulating sheets that do not melt in.
The method for producing a flat cable according to (8) or (9) above, wherein the heating conditions in the laminating process are 160 to 200 ° C. and 0.1 s to 5 s.

According to the flat cable of the present invention, the conductor is made of either tough pitch copper or oxygen-free copper, and the area ratio of crystal grains oriented in the direction of {123} <634> with an allowable deviation angle of 0 ° to 12.5 °. Has a rolled texture of 25% or more, so it has the strength of hard copper and prevents deformation and breakage of the conductor when an external force is applied to the conductor during the manufacture of flat cables and rotary connector devices. be able to. Further, when the steering wheel is steered in the vehicle after the rotary connector device is assembled to the vehicle and the flat cable in the rotary connector device repeatedly bends as the rotary connector device rotates clockwise or counterclockwise, bending is performed. To provide a flat cable in which the bending characteristics of the flat cable can be improved by preferentially growing the crystal grains in the Cube orientation at a relatively early stage, and the durability, reliability, and safety are improved. Is possible.

Further, according to the flat cable manufacturing method of the present invention, in order to control the structure of the conductor, the casting step, the hot rolling step and the cold rolling step are made common with the conventional conductor manufacturing step, and in the subsequent heat treatment step. Since the heat treatment conditions and the rolling ratio in the final rolling process are specified, the flat cable of the present invention can be obtained by changing only a part of the conventional conductor manufacturing process, and the cost increase can be suppressed. Become. In addition, since the degree of freedom in design increases due to the improvement of bending characteristics, the diameter of the rotary connector device is reduced by reducing the bending radius, the number of channels is increased by narrowing the conductor, or the connector is thinned by the same channel, or multiple channels. It is possible to reduce the number of flat cables due to the conversion. Further, since the conductor of the flat cable of the present invention is tough pitch copper or oxygen-free copper, it has excellent conductivity of pure copper, and it is not accompanied by a decrease in conductivity due to alloying as in Patent Document 1. It is possible to reduce the cross-sectional area of the conductor without limiting the degree of design freedom.

Further, the flat cable of the present invention includes not only a rotary connector device called a steering rolling connector (SRC), but also automobile parts such as a roof harness, a door harness, and a floor harness, and a bent portion of a foldable mobile phone. It is useful as a wiring body for moving parts such as digital cameras and printer heads, HDD (Hard Disk Drive), DVD (Digital Versatile Disc), Blu-ray (registered trademark) Disc, and CD (Compact Disc) drive parts. ..

It is a cross-sectional view in the width direction which shows the structure of the flat cable which concerns on embodiment of this invention. It is a partially enlarged sectional view which shows a preferable example of the flat cable of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Flat cable configuration]
As shown in FIG. 1, the flat cable 1 of the present embodiment includes, for example, a plurality of conductors 11-1, 11-2, 11-3, 11-4, 11-5, 11-6 (required number of conductors). A pair of insulating sheets 12 and 13 arranged so as to sandwich the plurality of conductors and an adhesive layer 14 provided between the pair of insulating sheets 12 and 13 are provided. The flat cable 1 of the present embodiment is, for example, a flexible flat cable (FFC).

The conductors 11-1 to 11-6 are arranged so as to be sandwiched between the pair of insulating sheets 12 and 13 via the adhesive layer 14 to form a laminated structure. The conductors 11-1 to 11-6 are arranged side by side so that the in-plane directions of the rolled surfaces are substantially the same, and an insulating sheet 12 is provided on one of the rolled surfaces of these conductors and the other rolled surface. An insulating sheet 13 is provided on the side. The conductors 11-1 to 11-6 have a width of 0.3 mm to 15 mm and a thickness of 0.02 mm to 0.065 mm. The number of conductors is 6 to 30 (6 to 30 channels), 4 to 6 (4 to 6 channels) depending on the application, and especially 1 (1 channel) in the case of a large current application.

The pair of insulating sheets 12 and 13 are made of a resin capable of exhibiting good adhesion to the adhesive layer 14 and / or a plurality of conductors 11-1 to 11-6. The insulating sheets 12 and 13 have, for example, a width of 6 mm to 15 mm and a thickness of 0.01 mm to 0.05 mm. The insulating sheets 12 and 13 are made of a material that does not melt under predetermined heating conditions described later when melting the adhesive layer, and are preferably made of polyethylene terephthalate having a melting point of, for example, 200 ° C. to 300 ° C.

The adhesive layer 14 has a sufficient thickness for embedding the plurality of conductors 11-1 to 11-6, and is sandwiched between the insulating sheets 12 and 13. The adhesive layer 14 is made of a material that can be melted under heating conditions of 160 to 200 ° C. and 0.1 s to 5 s, and is made of, for example, a polyester resin.

As a preferred example, the insulating sheet 22 has a layered adhesive portion 22a that can be melted under heating conditions described later and a layered base portion 22b that does not melt under the same heating conditions, and the insulating sheet 23 has a predetermined heating condition. It may have a layered adhesive portion 23a that can be melted in and a layered base portion 23b that does not melt under the heating conditions. In this case, the adhesive layers 22a and 23a are melted and integrated to form an adhesive layer between the base portions 22b and 23b.

The flat cable 1 configured as described above is preferably applied to a rotary connector device. The rotary connector device includes a flat cable 1 wound and housed in an annular internal space formed by a stator and a rotator (not shown). For example, in this rotary connector device, a folded-back portion (not shown) that is curved and folded back is provided at an intermediate portion in the longitudinal direction of the flat cable 1, and the flat cable 1 is wound while maintaining bending at the folded-back portion. Or it is rewound. Then, the folded-back portion is wound or rewound with folding back while maintaining a predetermined bending radius, for example, 4 mm to 8 mm.

[Chemical composition and structure of conductor]
The material of the conductor used in the present invention is pure copper and is composed of either tough pitch copper (TPC: Tough Pitch Copper) or oxygen-free copper (OFC: Oxygen-Free Copper). The tough pitch copper is composed of Cu ≧ 99.90 mass%, O (oxygen) of 0.01 to 0.03 mass% in general although there is no JIS regulation, and the balance of unavoidable impurities. Oxygen-free copper consists of Cu ≧ 99.96 mass% and the balance is unavoidable impurities.

Further, the conductor has a rolled texture in which the area ratio of crystal grains oriented at a permissible deviation angle of 0 ° to 12.5 ° in the orientation (also referred to as S orientation) of {123} <634> is 25% or more. Have. The crystal grains oriented in the direction of {123} <634> with an allowable deviation angle of 0 ° to 12.5 ° are the crystal grains oriented in the direction of {123} <634> and the orientation of {123} <634>. Both of the crystal grains oriented with an allowable deviation angle within 12.5 ° are shown. When the area ratio of the crystal grains oriented at the allowable deviation angle of 0 ° to 12.5 ° in the orientation of {123} <634> in the texture is a value within the above range, the Cube orientation in the conductor when the flat cable is bent. Grains can be grown preferentially, and higher flexibility can be imparted than conductors whose growth cannot be expected.

Further, when the width direction of the conductor is TD, the average value of the grain size in the thickness direction of the conductor is 3 μm or less, and the size of the crystal grain in the width direction of the conductor is the thickness direction of the conductor. The average value of the values divided by the size of the crystal grains is 3 or more. When the average value of the crystal grain size in the thickness direction of the conductor is 3 μm or less, the proof stress can be further improved. Further, if the average value obtained by dividing the size of the crystal grains in the width direction of the conductor by the size of the crystal grains in the thickness direction of the conductor is less than 3, the yield strength is lowered, which is not preferable. Therefore, in the present invention, the average value of the crystal grain dimensions in the thickness direction of the conductor and the average value of the crystal grain dimensions in the width direction of the conductor divided by the crystal grain dimensions in the thickness direction of the conductor are used. , Each value is within the above range.

[Conductor manufacturing method]
In the above-mentioned conductor manufacturing method, the conductor is first manufactured through the steps of [1] melting and casting, [2] hot rolling, [3] cold rolling, [4] heat treatment, and [5] final rolling. Then, slit cutting with a desired width is performed to prepare a plurality of conductors having a cross-sectional area of 0.03 mm ² or less, preferably 0.010 mm ^{2 to} 0.0195 mm ² . This desired cross-sectional area is in a signal system conductor, and is not limited to large current applications. The conductor width after final rolling is, for example, 0.3 mm to 0.8 mm, and the conductor thickness is, for example, 0.02 mm to 0.065 mm. In steps 1 to 6, which will be described later, the five steps of [1] melting and casting, [2] hot rolling, [3] cold rolling, [4] heat treatment, and [5] final rolling are common conditions. In processes 3 to 6, two additional steps of another heat treatment and another rolling are added after [4] heat treatment and before [5] final rolling.

[1] Melting and Casting In melting and casting, the amount of each component is adjusted and melted so as to have the same alloy composition as described above, and an ingot having a thickness of 100 mm to 200 mm is produced.

[2] Hot Rolling Next, the ingot produced above is hot-rolled at 600 to 1000 ° C. to prepare a plate material having a thickness of 10 mm to 20 mm.

[3] Cold Rolling Further, the plate material after the hot rolling treatment is cold-rolled to produce a conductor having a thickness of 0.04 mm to 1.2 mm. After the main cold rolling step and before the heat treatment described later, any processing such as cutting can be performed, but the value heat treatment is not performed.

[4] Heat treatment Next, the conductor is heat-treated under heat treatment conditions of 200 to 700 ° C. for 15s to 5h. A heat treatment that controls the recrystallization particle size to 20 μm or less is preferable.

[5] Final Rolling After that, the heat-treated conductor is subjected to final cold rolling to prepare a conductor having a thickness of 0.02 mm to 0.065 mm. The rolling rate (plate pressure reduction rate) of the final rolling is 75% or more, preferably 75 to 99%. As a result, a rolled texture is formed on the conductor in which the area ratio of the crystal grains oriented in the direction of {123} <634> with an allowable deviation angle of 0 ° to 12.5 ° is 25% or more. Further, the crystal grains of the material recrystallized in the above [4] are flattened by the final rolling, and the average value of the crystal grain dimensions in the thickness direction of the conductor is 3 μm or less. Further, the average value of the values obtained by dividing the size of the crystal grains in the width direction of the conductor by the size of the crystal grains in the thickness direction of the conductor is 3 or more.

[6] Others Two steps of another rolling and another heat treatment may be added after the above [4] heat treatment and before the above [5] final rolling. Specifically, after performing [1] melting and casting, [2] hot rolling and [3] cold rolling, [4] heat treatment (first heat treatment), the above-mentioned other rolling (first rolling), A conductor is manufactured through each of the above-mentioned other heat treatment (second heat treatment) and [5] final rolling (second heat treatment) steps in this order.

In this case, the heat treatment conditions of the [4] heat treatment (first heat treatment) are 200 to 700 ° C. and 15s to 5h, and the rolling ratio of the other rolling (first rolling) is 75% or less. When the rolling ratio of the first rolling exceeds 75%, crystal grains oriented in {001} <100> (Cube orientation) grow during the subsequent second heat treatment. Once {001} <100> is oriented in the heat treatment, the development of {001} <100> cannot be expected in the next heat treatment, so that the structure control within the range specified in the present invention becomes impossible. Therefore, the rolling ratio of the first rolling is set to a value within the above range.

The heat treatment conditions for the other heat treatment (second heat treatment) are 200 to 700 ° C. and 15s to 5h, and the rolling ratio of the final rolling (second rolling) is 75% or more. When the rolling ratio of the second rolling is 75% or less, the area ratio of the crystal grains oriented in the direction of {123} <634> in the conductor after the second rolling decreases, and the flat cable exhibits a long life when bent. Cube orientation accumulation cannot be sufficiently generated, which is not preferable. Therefore, the rolling ratio of the second rolling is set to a value within the above range.

[Manufacturing method of flat cable]
In the method for manufacturing a flat cable according to the present embodiment, when the conductor is manufactured by the strip forming step as described above, slit cutting is performed so that the width is 0.3 mm to 15 mm and the cross-sectional area in the width direction is 0.02 mm ² or less. Prepare the required number of conductors. This desired cross-sectional area is in a signal system conductor (width 0.3 to 2 mm), and is not limited to large current applications (width ≥ 2 mm). Then, insulating sheets are arranged on both sides of the main surface of the required number of conductors, and while applying a predetermined tension to each of the required number of conductors, the required number of conductors are attached to the pair of insulating sheets via an adhesive. Sandwich with. Then, a laminate composed of a required number of conductors, an adhesive, and a pair of insulating sheets is pressed and laminated.

Specifically, in the laminating process, after the final rolling step, two insulating sheets that do not melt under the heating conditions are passed through an adhesive that can be melted under the heating conditions of 160 to 200 ° C. and 0.1 s to 5 s. A laminated structure is formed by sandwiching a predetermined number of conductors obtained in the final rolling step. In this laminating treatment, for example, the laminated body is sandwiched between a pair of rolls, and the heating conditions (roll temperature) during the laminating treatment are preferably 160 to 200 ° C. and 0.1 s to 5 s, preferably 160 to 200 ° C. It is more preferably 0.5 s to 5 s. If the heating conditions during the laminating process are within the above range, the insulating sheet will not melt during the laminating process even if an insulating sheet made of a resin having a low melting point such as PET is used, while suppressing an increase in cost. Productivity can be improved.

When heat is applied to the conductor during this laminating process, by setting the heating conditions to a value within the above range, the area ratio of the crystal grains oriented in the direction of {123} <634> in the conductor does not decrease. The laminating treatment is performed while maintaining the area ratio of the crystal grains oriented in the direction of {123} <634> in the conductor after the second rolling.

Further, under the above heating conditions, recrystallization in which the Cube orientation is highly developed does not occur during heating of the laminating treatment, and the strength of the conductor does not decrease. Therefore, not only during the laminating treatment but also after joining the flat cable and the connector or When the flat cable is stored in the rotary connector device, the conductor is less likely to be deformed or broken, and a decrease in productivity can be prevented.

Further, in the case of the conductor according to the present embodiment, even if the plurality of conductors are sandwiched between a pair of insulating sheets while applying a predetermined tension to each conductor, the laminate can be manufactured without causing plastic deformation of the conductors. Further, even when a flat cable is manufactured according to a predetermined guideline in which laminating treatment conditions are defined, it is possible to provide a flat cable having high safety and reliability according to the guideline.

In the laminating process, a predetermined number of conductors are sandwiched between a pair of insulating sheets consisting of a layered adhesive portion that can be melted under the heating conditions and a layered base portion that does not melt under the same heating conditions, and a required number of conductors and a pair of adhesives are bonded. A laminate consisting of a portion and a pair of base portions may be pressed for laminating.

[Characteristics of conductors in flat cables]
In the flat cable manufactured by the above method, the 0.2% proof stress of the conductor is 400 MPa or more, and the 0.2% proof stress of the conductor after heat treatment at 160 to 200 ° C. and 0.1 s to 5 s is 300 MPa. That is all. By setting the 0.2% proof stress of the conductor before the laminating treatment to a value within the above range, it is possible to prevent the conductor from breaking during the laminating treatment, and at 160 to 200 ° C. and 0.1s to 5s. By setting the 0.2% proof stress of the conductor after the heat treatment to a value within the above range, good bending characteristics can be obtained by considering the bendability and buckling resistance after the laminate treatment while maintaining an appropriate proof stress. It becomes possible to obtain.

Further, as a result of performing an IPC bending test under the test conditions of 50 ° C. or higher, a stroke length of 10 mm to 15 mm, and a bending speed of 10 to 500 rotations / minute, the conductor is the part to be bent after the bending test 100,000 times. It has an texture in which the area ratio of the crystal grains oriented in the direction of {001} <100> is 75% or more. Further, as a result of performing an IPC bending test under the test conditions of 50 to 150 ° C., a bending radius of 4.5 mm to 6.5 mm, a stroke length of 10 mm to 15 mm, and a bending speed of 10 to 500 rotations / minute, the conductor was found to be. It is preferable to have an texture in which the area ratio of the crystal grains oriented in the direction of {001} <100> of the bent portion after the 100,000 times bending test is 75% or more. Due to the bending as described above, at least a part of the rolled texture of the conductor is changed to form the texture. Further, if the area ratio of the crystal grains oriented in the direction of {123} <634> within the allowable deviation angle of 12.5 ° in the conductor after the laminating treatment is within the above range, it does not grow before the bending test. When the {001} <100> orientation grain is adjacent to the {123} <634> orientation grain, the grain boundary can be moved with lower energy than other orientation grains, and as a result, the Cube grain is preferentially grown. be able to. Therefore, if the area ratio of the crystal grains oriented in the direction of {001} <100> of the bent portion after the 100,000 times bending test is a value within the above range, the flat cable is assembled to a device such as a rotary connector device. When it is actually used, it can achieve a long life.

Hereinafter, examples of the present invention will be described in detail.

First, a casting machine was used to prepare an ingot having a thickness of 100 mm to 200 mm made of tough pitch copper. Next, a plate material having a thickness of 10 to 20 mm was produced by hot rolling at 600 to 1000 ° C., and then cold rolling was performed.

After passing through the above common steps, as shown in Table 1, in Process 1 of Invention Example 1, the plate material was heat-treated at a treatment temperature of 300 ° C. and a treatment time of 2 hours, and then finally rolled at a reduction rate of 97%. A conductor having a thickness of 0.035 mm was obtained.
Further, in the process 2 of Invention Example 2, the plate material was heat-treated at a treatment temperature of 170 ° C. and a treatment time of 2 hours, and then rolled at a reduction rate of 97% to obtain a conductor having a thickness of 0.035 mm.

In the process 3 of Invention Example 3, the plate material is subjected to the first heat treatment at a treatment temperature of 200 ° C. and the treatment time is 2 hours, and then the plate material after the first heat treatment is subjected to the first rolling at a rolling reduction of 67% to have a thickness of 0. A conductor of .4 mm was obtained, and then the conductor was subjected to a second heat treatment at a treatment temperature of 300 ° C. and a treatment temperature of 2 hours, and the plate material after the second heat treatment was further subjected to a second rolling at a rolling reduction of 91% to obtain a thickness of 0. A 035 mm conductor was obtained.

In the process 4 of Comparative Example 1, a conductor having a thickness of 0.035 mm was obtained in the same manner as in the process 3 except that the rolling reduction ratio of the first rolling was 83% and the rolling reduction ratio of the second rolling was 83%.

In the process 5 of Comparative Example 2, a conductor having a thickness of 0.035 mm was obtained in the same manner as in the process 3 except that the rolling reduction ratio of the first rolling was 92% and the rolling reduction ratio of the second rolling was 65%.

In the process 6 of Comparative Example 3, a conductor having a thickness of 0.035 mm was obtained in the same manner as in the process 3 except that the rolling reduction ratio of the first rolling was 96% and the rolling reduction ratio of the second rolling was 30%.

Then, for each of the produced conductors of Invention Examples 1 to 3 and Comparative Examples 1 to 3, the area ratio of the crystal grains oriented in the direction of {123} <634> and the average value of the size of the crystal grains in the thickness direction of the conductor. , And the average value of the values obtained by dividing the size of the crystal grains in the width direction of the conductor by the size of the crystal grains in the thickness direction of the conductor was measured by the methods (A) to (C) below, respectively, and 0.2. % Strength was measured by the method (D) below.

(A) Area ratio of crystal grains oriented in the direction of {123} <634> As a preprocessing treatment, a cross section polisher process is applied to the conductor cross section to expose the copper surface, and then the range of 200 μm × 35 μm is stepped 0. Electron Backscatter Diffraction (EBSD) is performed at 1 μm to 0.3 μm, and the orientation is oriented in the direction of {123} <634> with an allowable deviation angle of 12.5 ° or less using analysis software. The area ratio of crystal grains was analyzed.

(B) Mean value of crystal grain size in the thickness direction of the conductor From the IPF MAP measured and analyzed by the above EBSD, the number of crystal grains is counted along the thickness direction of the conductor, divided by the conductor thickness, and the crystal is formed. The average value of the grain size was calculated.

(C) Average value obtained by dividing the grain size in the width direction of the conductor by the size of the crystal grain in the thickness direction of the conductor. The width direction of the conductor is the TD direction (direction perpendicular to the rolling direction), and the thickness direction is Obtain the size of the crystal grain at a length of 100 μm in the width direction by the same method as the size of the crystal grain, and divide by the size of the crystal grain in the thickness direction to obtain (width direction crystal grain size) / (thickness direction crystal grain size). ) Was calculated.

(D) 0.2% proof stress 0.035 mm thick, 0.8 mm wide, 160 mm long strips were made by slit cutting, and the strips were tested in accordance with JIS Z 2241 except for the size of the test piece. The average value of the three lines was calculated. A case where the 0.2% proof stress was 400 MPa or more was regarded as good, and a case where the 0.2% proof stress was less than 400 MPa was regarded as a defect. The results measured by the above method are shown in Table 1.

From the results in Table 1, in Invention Example 1, the area ratio of the conductor material and the crystal grains oriented in the direction of {123} <634> was within the range of the present invention, and the 0.2% proof stress was 440 MPa. ..
Further, in Invention Example 2, the area ratio of the material of the conductor and the crystal grains oriented in the direction of {123} <634> is within the range of the present invention, and further, the average value of the dimensions of the crystal grains in the thickness direction of the conductor. Was 2 μm, the average value of (grain size in the width direction) / (crystal grain size in the thickness direction) was 5, and the 0.2% strength was 455 MPa.
In Invention Example 3, the area ratio of the conductor material and the crystal grains oriented in the direction of {123} <634> was within the range of the present invention, and the 0.2% proof stress was 430 MPa.

On the other hand, in Comparative Examples 1 to 3, since the rolling ratio was high in the first rolling, crystal grains oriented in the direction of {001} <100> grew during the second heat treatment, and {123} after the final rolling. The area ratio of the crystal grains oriented in the direction of <634> was out of the range of the present invention, and the 0.2% proof stress was inferior to 310 MPa.

Next, as an example of the invention 4, two PET insulating sheets with an adhesive layer (manufactured by Riken Technos Co., Ltd., for airbags) are applied to the conductors obtained in the process 1 of Table 1 while applying a tension of 0.3 kgf per wire. A flat cable was produced by sandwiching it between a flexible flat cable (insulating film), a base layer thickness of 25 μm, and an adhesive layer thickness of 20 μm) and pressing from both sides to perform a laminating treatment. As the adhesive layer, a polyester resin that can be melted under heating conditions of 160 to 200 ° C. and 0.1s to 5s was selected, and as the base layer, a PET resin that did not melt under the above heating conditions was selected. The laminating treatment conditions were a roll temperature of 170 ° C., a heating time (pressing time) of 5 s, and a pressing pressure of 0.5 MPa.

As Invention Example 5, a flat cable was produced in the same manner as in Invention Example 4 except that the conductor obtained in Process 2 was used. Further, as Invention Example 6, a flat cable was produced in the same manner as in Invention Example 4 except that the conductor obtained in Process 3 was used.

Next, as Comparative Example 4, the conductor obtained in Process 1 of Table 1 is subjected to a PI insulating sheet (manufactured by Toray DuPont, product name "Kapton F type", or Ube Kogyo) while applying a tension of 0.3 kgf. A flat cable was produced by sandwiching it with a product name "UPIREX (registered trademark) -VT / NVT" (thickness 10 to 50 μm) manufactured by Toray Industries, Inc., and pressing it from both sides to perform a laminating process. The laminating treatment conditions were a roll temperature of 300 ° C., a heating time (pressing time) of 180 s, and a pressing pressure of 0.5 MPa.

As Comparative Example 5, a flat cable was produced in the same manner as in Comparative Example 4 except that the roll temperature during the laminating process was changed to 170 ° C. Further, as Comparative Example 6, a flat cable was produced in the same manner as in Comparative Example 4 except that a PET insulating sheet with an adhesive layer was used.

As Comparative Example 7, a flat cable was produced in the same manner as in Comparative Example 4 except that the conductor obtained in Process 2 was used. Further, as Comparative Example 8, a flat cable was produced in the same manner as in Comparative Example 5 except that the conductor obtained in Process 2 was used. Further, as Comparative Example 9, a flat cable was produced in the same manner as in Comparative Example 6 except that the conductor obtained in Process 2 was used.

As Comparative Example 10, a flat cable was produced in the same manner as in Comparative Example 4 except that the conductor obtained in Process 3 was used.

As Comparative Example 11, a flat cable was produced in the same manner as in Comparative Example 4 except that the conductor obtained in Process 4 was used. Further, as Comparative Example 12, a flat cable was produced in the same manner as in Comparative Example 5 except that the conductor obtained in Process 4 was used.

As Comparative Example 13, a flat cable was produced in the same manner as in Comparative Example 4 except that the conductor obtained in Process 5 was used. Further, as Comparative Example 14, a flat cable was produced in the same manner as in Comparative Example 5 except that the conductor obtained in Process 5 was used.

As Comparative Example 15, a flat cable was produced in the same manner as in Comparative Example 4 except that the conductor obtained in Process 6 was used. Further, as Comparative Example 16, a flat cable was produced in the same manner as in Comparative Example 5 except that the conductor obtained in Process 6 was used.

Then, for each of the produced flat cables of Invention Examples 4 to 6 and Comparative Examples 4 to 16, the area ratio of the crystal grains oriented in the direction of {123} <634> after the laminating treatment, and 0 of the conductor after the laminating treatment. .2% proof stress, laminate property, connector bondability, room temperature test life, high temperature test life, and area ratio of crystal grains oriented in the direction of {123} <634> after 100,000 bending tests at high temperature are as follows. It was measured and evaluated by the methods (E) to (J).

(E) Area ratio of crystal grains oriented in the direction of {123} <634> after laminating treatment For the conductor after laminating treatment, the conductor of {123} <634> was subjected to EBSD in the same manner as in (A) above. The area ratio of the crystal grains oriented in the orientation was determined.

(F) In a 0.2% proof stress flat cable after laminating treatment, the resin was dissolved in a predetermined solvent, and the average value of three tests was calculated for the conductor taken out by the same method as in (D) above. did.

(G) Laminating property If the conductors are shrunk or separated by 1/10 or more of the design distance during the laminating process, or if the conductors are permanently stretched by 1% or more, the laminating property is regarded as poor "x" and the conductors are separated from each other. When the conductor was not shrunk or separated by 1/10 or more of the design distance and the conductor was not permanently stretched by 1% or more, the laminate property was set to “◯”.

(H) Connector Bondability A case where the conductor was broken during connector joining was evaluated as a defective “x”, and a case where the conductor was not broken was evaluated as a good “〇”.

(I) Room temperature bending life and high temperature bending life Using an FPC bending tester (manufactured by Ueshima Seisakusho, device name "FT-2130"), a flat cable in which 4 to 6 conductors are arranged and laminated with resin is used as a test sample. When any of the conductors arranged at both ends in the width direction of the flat cable was broken, the life was determined. The test conditions were a stroke of ± 13 mm, a test speed of 180 rpm, a bending radius of 5.5 mm, a room temperature of 23 ° C., and a high temperature of 85 ° C. When the life is judged to be 300,000 times or more, it is extremely good as "A" as satisfying the fatigue characteristics required for the rotary connector, and when it is 150,000 times or more and less than 300,000 times, it is good. "B" and less than 150,000 times were regarded as defective "C".

(J) Area ratio of crystal grains oriented in the direction of {001} <100> after 100,000 times high temperature bending test 100,000 times bending test at high temperature (85 ° C.) is performed by the same method as in (I) above. After that, the area ratio of the crystal grains oriented in the direction of {001} <100> was determined by the same method as in (E) above. Table 2 shows the results of measurement and evaluation by the above method.

As shown in Table 2, in Invention Example 4, the conductor produced in Process 1 is used, the laminating material is the PET insulating sheet with an adhesive layer, and the heating conditions in the laminating process are 170 ° C. and 3 s. Both the property and the connector bondability were good. Further, the area ratio of the crystal grains oriented in the direction of {123} <634> after the laminating treatment is within the range of the present invention, the 0.2% proof stress after the laminating treatment is 420 MPa, and the room temperature bending life is good. At the same time, the high temperature bending life was extremely good. Further, the area ratio of the crystal grains oriented in the direction of {001} <100> after the 100,000 high temperature bending test was 97%, and it was found that the crystal grains oriented in the Cube direction were grown by bending.

In Invention Example 5, the conductor produced in the process 2 is used, the laminating material is the PET insulating sheet with an adhesive layer, and the heating conditions in the laminating process are 170 ° C. and 3 s. Therefore, both the laminate property and the connector bondability are both. Was good. Further, the area ratio of the crystal grains oriented in the direction of {123} <634> after the laminating treatment is within the range of the present invention, the 0.2% proof stress after the laminating treatment is 420 MPa, and the thickness of the conductor is further increased. The average value of the crystal grain dimensions in the direction is 2 μm, and the average value of (width direction crystal grain size) / (thickness direction crystal grain size) is 5, and not only the high temperature bending life but also the room temperature bending life is extremely long. It was good. Furthermore, the area ratio of the crystal grains oriented in the direction of {001} <100> after the 100,000 times high temperature bending test was 95%, and it was found that the crystal grains oriented in the Cube direction were sufficiently grown by bending. ..

In Invention Example 6, the conductor manufactured in the process 3 is used, the laminating material is the PET insulating sheet with an adhesive layer, and the heating conditions in the laminating treatment are 170 ° C. and 3 s. Therefore, both the laminate property and the connector bondability are both. Was good. Further, the area ratio of the crystal grains oriented in the direction of {123} <634> after the laminating treatment is within the range of the present invention, the 0.2% proof stress after the laminating treatment is 430 MPa, and the room temperature bending life is good. At the same time, the high temperature bending life was extremely good. Further, it was found that the area ratio of the crystal grains oriented in the direction of {001} <100> after the high temperature bending test 100,000 times was 80%, and the crystal grains oriented in the Cube direction were grown by bending.

On the other hand, in Comparative Example 4, since the conductor produced in Process 1 is used, the laminating material is a PI insulating sheet, and the heating conditions in the laminating treatment are 300 ° C. and 3s, the conductor softens during the laminating treatment and has a laminating property. And both the connector connectivity was poor.

In Comparative Example 5, the conductor produced in Process 1 is used, the laminating material is a PI insulating sheet, and the heating conditions in the laminating process are 170 ° C. and 3 s. Therefore, the PI insulating sheet does not melt during the laminating process and is flat. The cable could not be made.

In Comparative Example 6, the conductor manufactured in the process 1 is used, the laminating material is a PET insulating sheet with an adhesive layer, and the heating conditions in the laminating process are 300 ° C. and 3 s. Therefore, not only the adhesive layer but also the base is used during the laminating process. The layers melted and became uncontrollable, making it impossible to form flat cables.

In Comparative Example 7, the conductor produced in Process 2 is used, the laminating material is a PI insulating sheet, and the heating conditions in the laminating process are 300 ° C. and 3 s. Therefore, as in Comparative Example 4, the conductor softens during the laminating process. However, both the laminate property and the connector bondability were poor.

In Comparative Example 8, the conductor produced in Process 2 is used, the laminating material is a PI insulating sheet, and the heating conditions in the laminating process are 170 ° C. and 3 s. Therefore, as in Comparative Example 5, the PI insulating sheet is used during the laminating process. Did not melt and the flat cable could not be made.

In Comparative Example 9, the conductor manufactured in Process 2 is used, the laminating material is a PET insulating sheet with an adhesive layer, and the heating conditions in the laminating treatment are 300 ° C. and 3s. Therefore, as in Comparative Example 6, during the laminating treatment Not only the adhesive layer but also the base layer melted and became uncontrollable, making it impossible to form a flat cable.

In Comparative Example 10, the conductor produced in Process 3 is used, the laminating material is a PI insulating sheet, and the heating conditions in the laminating treatment are 300 ° C. and 3s. Therefore, as in Comparative Example 4, the conductor softens during the laminating treatment. However, both the laminate property and the connector bondability were poor.

In Comparative Example 11, the conductor manufactured in Process 4 is used, the laminating material is a PI insulating sheet, and the heating conditions in the laminating process are 300 ° C. and 3 s. Therefore, as in Comparative Example 4, the conductor softens during the laminating process. However, both the laminate property and the connector bondability were poor.

In Comparative Example 12, the conductor produced in the process 4 is used, the laminating material is a PET insulating sheet with an adhesive layer, and the heating conditions in the laminating process are 170 ° C. and 3 s. Therefore, both the laminate property and the connector bondability are improved. Although it was good, the area ratio of the crystal grains oriented in the direction of {123} <634> after the laminating treatment was out of the range of the present invention, the 0.2% proof stress after the laminating treatment was 310 MPa, and the room temperature. Both the bending life and the high temperature bending life were poor. Further, it was found that the area ratio of the crystal grains oriented in the direction of {001} <100> after the 100,000 times high temperature bending test was 15%, and the crystal grains in the Cube orientation hardly grew due to the bending.

In Comparative Example 13, the conductor produced in the process 5 is used, the laminating material is a PI insulating sheet, and the heating conditions in the laminating process are 300 ° C. and 3 s. Therefore, as in Comparative Example 4, the conductor softens during the laminating process. However, both the laminate property and the connector bondability were poor.

In Comparative Example 14, the conductor produced in the process 5 is used, the laminating material is a PET insulating sheet with an adhesive layer, and the heating conditions in the laminating treatment are 170 ° C. and 3 s. Therefore, {123} <634 before the laminating treatment. Since the area ratio of the crystal grains oriented in the> direction is outside the range of the present invention and the 0.2% proof stress of the conductor before the laminating treatment is 250 MPa, both the laminating property and the connector bondability are poor. ..

In Comparative Example 15, the conductor produced in the process 6 is used, the laminating material is a PI insulating sheet, and the heating conditions in the laminating process are 300 ° C. and 3 s. Therefore, as in Comparative Example 4, the conductor softens during the laminating process. However, both the laminate property and the connector bondability were poor.

In Comparative Example 16, the conductor produced in the process 6 is used, the laminating material is a PET insulating sheet with an adhesive layer, and the heating conditions in the laminating treatment are 170 ° C. and 3 s. Therefore, {123} <634 before the laminating treatment. Since the area ratio of the crystal grains oriented in the> direction is outside the range of the present invention and the 0.2% proof stress before the laminating treatment is 230 MPa, both the laminating property and the connector bondability are poor.

1 Flexible flat cable 11-1, 11-2, 11-3 Conductor 11-4, 11-5, 11-6 Conductor 12, 13 Pair of insulating sheets 14 Adhesive layer 22 Insulation sheet 22a Base layer 22b Adhesive layer 23 Insulation sheet 23a Base layer 23b Adhesive layer

Claims (9)

Rolled texture consisting of either tough pitch copper or oxygen-free copper and having an area ratio of crystal grains of 25% or more oriented in the direction of {123} <634> with an allowable deviation angle of 0 ° to 12.5 °. comprising a predetermined number of conductors having,
As a result of performing an IPC bending test under test conditions of 50 ° C. or higher, a stroke length of 10 mm to 15 mm, and a bending speed of 10 to 500 rotations / minute, the conductor was found to be {001 of the bent portion after the bending test 100,000 times. } grain area ratio of oriented along <100> is characterized Rukoto that have a at which texture 75% or more, the flat cable. The average value of the crystal grain dimensions in the thickness direction of the conductor is 3 μm or less, and the average value obtained by dividing the grain size in the width direction of the conductor by the crystal grain size in the thickness direction of the conductor. The flat cable according to claim 1, wherein the value is 3 or more. The conductor has a 0.2% proof stress of 400 MPa or more, and the conductor has a 0.2% proof stress of 300 MPa or more after heat treatment at 160 to 200 ° C. and 0.1 s to 5 s. The flat cable according to claim 1 or 2. An adhesive layer made of a material that can be melted under heating conditions of 160 to 200 ° C. and 0.1s to 5s, and a pair of insulating sheets made of a material that does not melt under the heating conditions are further provided.
The flat according to any one of claims 1 to 3, wherein the conductor is arranged so as to be sandwiched between the pair of insulating sheets via the adhesive layer to form a laminated structure. cable. The flat cable according to claim 4 , wherein the insulating sheet is made of polyethylene terephthalate. A rotary connector device including the flat cable according to any one of claims 1 to 5. Rolled texture consisting of either tough pitch copper or oxygen-free copper and having an area ratio of crystal grains of 25% or more oriented at a permissible deviation angle of 0 ° to 12.5 ° in the orientation of {123} <634>. comprising a predetermined number of conductors with, 50 ° C. or more, the stroke length 10 mm to 15 mm, a result of the IPC bending test at a bending speed of 10 to 500 rev / min of the test conditions, the conductor is 100,000 times bending a method of manufacturing a flat cable that crystal grains of the area ratio of oriented along {001} <100> of the bent portion after test have a texture 75% or more,
It has a heat treatment step and a final rolling step after a casting step, a hot rolling step and a cold rolling step of a material made of either tough pitch copper or oxygen-free copper.
The heat treatment conditions in the heat treatment step are 200 to 700 ° C. and 15s to 5h.
The rolling ratio in the final rolling step is 75% or more.
A method of manufacturing a flat cable, which is characterized in that. Rolled texture consisting of either tough pitch copper or oxygen-free copper and having an area ratio of crystal grains of 25% or more oriented at a permissible deviation angle of 0 ° to 12.5 ° in the orientation of {123} <634>. comprising a predetermined number of conductors with, 50 ° C. or more, the stroke length 10 mm to 15 mm, a result of the IPC bending test at a bending speed of 10 to 500 rev / min of the test conditions, the conductor is 100,000 times bending a method of manufacturing a flat cable that crystal grains of the area ratio of oriented along {001} <100> of the bent portion after test have a texture 75% or more,
After the casting step, hot rolling step and cold rolling step of the material consisting of tough pitch copper or oxygen-free copper, the first heat treatment step, the first rolling step, the second heat treatment step, and the final rolling step Have,
The heat treatment conditions in the first heat treatment step are 200 to 700 ° C. and 15s to 5h.
The rolling ratio in the first rolling step is 75% or less.
The heat treatment conditions in the second heat treatment step are 200 to 700 ° C. and 15s to 5h.
The rolling ratio in the final rolling step is 75% or more.
A method of manufacturing a flat cable, which is characterized in that. After the final rolling step, a predetermined number of conductors obtained in the final rolling step are not melted under the heating conditions via an adhesive that can be melted under heating conditions of 160 to 200 ° C. and 0.1s to 5s. It further has a laminating process of forming a laminating structure by sandwiching it between two insulating sheets.
The method for manufacturing a flat cable according to claim 7 or 8 , wherein the heating conditions in the laminating process are 160 to 200 ° C. and 0.1 s to 5 s.

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