JP2009117275A - Manufacturing method of plated rectangular conductor, and flexible flat cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a plated rectangular copper conductor in which thickness of a plated layer of nickel or tin is more uniform, concretely meaning that a ratio of the maximum value to the minimum value of the plated layer is 1.05 or less, as the plated rectangular copper conductor for a flexible flat cable, to provide an FFC superior in corrosion resistance by using the obtained plated rectangular copper conductor, and furthermore to provide the FFC in which few whiskers are formed in the case it is mounted on a terminal of a connector, and a short circuit does not occur between copper wirings or the like. <P>SOLUTION: For example, problems are solved by the manufacturing method that an Ni plated copper wire drawn to a prescribed diameter is drawn into the Ni plated copper conductor of a rectangular cross section by using a profiled die, and the Ni plated rectangular conductor is prepared by rolling processing. Moreover, the problems are solved by making the FFC in which a plurality of numbers of the Ni plated rectangular conductors obtained by the manufacturing method are used and laminated by an insulating tape with an adhesive at a necessary spacing, and arranged in parallel, and a connecting part is formed at its end part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a nickel or tin plated rectangular conductor and a flexible flat cable using the same.

Along with the downsizing and weight reduction of electronic devices and the like, the wiring materials to be mounted are also downsizing. For this reason, the space is limited and the flexibility is required. For example, a flexible flat cable is used in which a plurality of flat conductors are arranged in a plane and laminated from both sides with a tape-like insulator material. This flexible flat cable is connected to a printed wiring board or the like by calibrating the terminal portion, but in order to reduce contact resistance or improve solderability, the flat conductor is usually tin-based (Sn-based). Plating) or gold / nickel plating (Au / Ni plating). And it is supposed that these plating layers are so preferable that the surface is uniform. Such a flat conductor is usually formed by plating a copper wire having a diameter of about Φ0.5 to 1 mm, then drawing the wire to a diameter of about Φ0.1 to 0.2 mm, and further rolling the flat conductor. . Such a technique is described in Patent Document 1, for example. However, in such a manufacturing method, since the copper round wire is rolled flat, the processing strain in the material such as the copper round wire is not uniform, and a portion that deforms greatly and a portion that hardly deforms occur. become. Of course, the plating layer applied thereon is also subjected to the same deformation, and the thickness of the plating layer is not uniform as a whole, and a large difference occurs depending on the place. Specifically, the plating layer is thick at the central portion of the flat conductor in contact with the rolling roll, and the portion between the central portion and both end portions tends to be thin. Thus, when the thickness of a plating layer becomes non-uniform | heterogenous, the performance of a plating layer will be impaired and it becomes unpreferable. For example, in the case of Au / Ni two-layer plating, the Ni layer prevents the copper from diffusing into the Au layer as a barrier layer. However, if a thin portion occurs in the Ni layer, the copper diffuses into the Au layer. Then, the copper reaching the surface of the plating layer significantly deteriorates the corrosion resistance of the Au plating layer. Such poor corrosion resistance is undesirable because it leads to an increase in contact resistance and a decrease in solderability. In the case of an Sn-based plating layer, it is known that needle crystals called whiskers grow from a peripheral plating layer pressed against a connector terminal when fitted with a connector. Such whisker growth is not preferable because it causes a short circuit between copper wirings and leads to troubles in electronic equipment. In order to suppress the growth of the whisker, it is effective to suppress the thickness of the pure tin layer of the Sn-based plating layer to a predetermined thickness or less. On the other hand, the solder wettability is better as the plating layer is thicker. For this reason, it is desirable that the plated layer of the flat rectangular conductor after rolling is uniform. For this reason, a technique as disclosed in Patent Document 2 has been proposed. That is, simultaneously with the rotation of the upper and lower rolling rolls on the plated round wire conductor, the rotation axis of the upper rolling roll is crossed with the rotation axis of the upper rolling roll along the plane parallel to the rolling surface of the lower rolling roll. A method of rolling while repetitively moving with respect to the rotational speed is disclosed. And according to such a rolling method, a flat conductor for a flexible flat cable with a uniform plated layer after rolling can be obtained, but still about 1.2 times on average between the thick and thin portions of the plated layer. There may be a difference, and the effect of making uniform may not be sufficient.
Japanese Patent No. 3005742 JP 2007-95633 A

  Therefore, the problem to be solved by the present invention is that, as a plated flat copper conductor for a flexible flat cable (hereinafter referred to as FFC), the thickness of the plated layer of nickel or tin is more uniform, specifically, the maximum value of the plated layer Provided is a method for producing a plated rectangular copper conductor having a minimum value ratio of 1.05 or less, and obtaining an FFC with good corrosion resistance by using the obtained plated rectangular copper conductor. An object of the present invention is to provide an FFC in which no whisker is generated and no short circuit occurs between copper wirings.

  The problem to be solved is a nickel-plated round copper wire (Ni, plated copper wire) drawn to a predetermined diameter using a deformed die, and a cross-section of the Ni-plated Ni wire as described in claim 1. The problem is solved by drawing the plated copper conductor and rolling it into a method for producing a Ni-plated rectangular copper conductor (hereinafter, Ni-plated rectangular conductor). In addition, as described in claim 2, a plurality of Ni-plated flat conductors obtained by the manufacturing method are laminated in parallel with an insulating tape with an adhesive at a necessary interval, and are arranged at the ends. Is solved by using the FFC in which the connection portion is formed.

  Furthermore, as described in claim 3, a tin-plated round copper wire (hereinafter, Sn-plated copper wire) drawn to a predetermined diameter is drawn into a Sn-plated copper conductor having a square cross section using a deformed die. This is solved by forming a Sn-plated flat copper conductor (hereinafter referred to as Sn-plated flat conductor) by rolling. Furthermore, as described in claim 4, a plurality of Sn-plated flat conductors obtained by the manufacturing method are laminated in parallel by an insulating tape with an adhesive at a necessary interval, and ends thereof This can be solved by using an FFC in which a connection portion is formed.

  According to the present invention as described above, a Ni-plated round copper wire drawn to a predetermined diameter is drawn into a Ni-plated copper conductor having a square cross section using a deformed die, and this is rolled Ni Since it is a manufacturing method of a plating flat conductor, the Ni plating flat conductor whose thickness of Ni plating layer is more uniform, specifically, the ratio of the maximum value and minimum value of a plating layer is 1.05 or less is obtained. Further, an FFC in which a plurality of Ni-plated flat conductors obtained by the manufacturing method are laminated in parallel with an insulating tape with an adhesive at a necessary interval and arranged at the end thereof. Therefore, it is possible to provide an FFC that does not cause a short circuit between copper wirings due to corrosion or the like due to good corrosion resistance. Furthermore, the bending characteristics of the FFC are also improved.

  In addition, this is a method for producing a Sn-plated rectangular conductor obtained by drawing a Sn-plated copper wire drawn to a predetermined diameter into a Sn-plated copper conductor having a square cross section using a deformed die and rolling it. As a plated flat conductor for FFC, the thickness of the plated layer is more uniform and thin. Specifically, a Sn plated flat conductor having a ratio of the maximum value and the minimum value of the plated layer of 1.05 or less is obtained. Further, such an Sn-plated flat conductor is preferable from the viewpoint of manufacturing cost because it is not necessary to use an amount of Sn plating more than necessary. In addition, a connector is provided by forming a plurality of the Sn-plated flat conductors in parallel by laminating them with an insulating tape with an adhesive at a necessary interval, and having a connection portion formed at an end thereof. When it is attached to the terminal, whisker is not generated, and the FFC does not cause a short circuit between copper wirings. Furthermore, the bending characteristics of the FFC are also improved.

  The present invention is described in detail below. The invention described in claim 1 relates to a method for manufacturing a Ni-plated flat conductor preferable for FFC, and a Ni-plated copper wire drawn to a predetermined diameter is formed using a deformed die and has a rectangular cross section. This is a manufacturing method in which a plated conductor is drawn and formed into a Ni-plated rectangular conductor by rolling. According to such a manufacturing method, since the thickness of the plating layer of the Ni-plated rectangular conductor can be made more uniform, the corrosion resistance can be improved.

  The manufacturing method will be described with reference to the schematic diagram shown in FIG. Reference numeral 1 denotes a Ni-plated copper wire drawn to a predetermined diameter, and the copper wire 2 is usually drawn to about 0.1 to 0.2 mm and provided with a Ni plating layer 3. Next, the Ni plated copper wire 1 is drawn through a deformed die 4 having a square hole before rolling. The hole has a rectangular shape with a length of about 0.07 to 0.18 mm and a width of about 0.09 to 0.20 mm. The quadrangle is usually a square or a rectangle, but a rectangle is particularly preferable. Usually, in this step, surface reduction processing is performed up to about 0.1%. In this manner, after the wire is once drawn on the Ni-plated conductor 5 having a square cross section, the target Ni-plated flat conductor 6 is obtained by a normal rolling process. In this way, the Ni-plated conductor 5 having a square cross section is rolled with a rolling roll to form the Ni-plated flat conductor 6, because the processing strain in the material such as Ni-plated copper wire is removed. The thickness of the plating layer can be uniform throughout the plating layer without being deformed. That is, the central part of the flat conductor in contact with the rolling roll has a thick plating layer, and the part between the central part and both end parts tends to be thinned. Thus, even if a normal rolling process is performed thereafter, a rectangular conductor having a uniform Ni plating layer can be obtained without the above-mentioned problems. Specifically, a Ni-plated rectangular conductor in which the ratio between the maximum value and the minimum value of the plating layer is 1.05 or less can be obtained. In this way, the Ni-plated rectangular conductor 6 having a uniform Ni plating layer has a thin portion in the Ni layer and copper diffuses into the Au layer, and the copper reaching the surface of the plating layer significantly improves the corrosion resistance of the Au plating layer. There is no problem to make it worse.

  And, as described in claim 2, by manufacturing the FFC using the Ni plated rectangular conductor manufactured by the above manufacturing method, the Ni plated layer for a rectangular conductor having a very uniform Ni plated layer. Therefore, an FFC that does not cause a short circuit between copper wirings can be provided. Note that FFC is usually an insulating film made of polyethylene terephthalate (hereinafter referred to as PET) or polyimide resin (hereinafter referred to as PI) in which several to several tens of rectangular conductors plated with Ni are arranged in parallel at predetermined intervals. Is manufactured by forming a connection terminal portion to be connected to the electrical connector at at least one end portion. The terminal portion is provided with an Au plating layer having a thickness of about 0.03 to 1.00 μm to form a connection terminal portion. Furthermore, this FFC has excellent bending characteristics.

  Furthermore, the manufacturing method of the Sn-plated rectangular conductor according to claim 3, the Sn-plated copper wire drawn to a predetermined diameter is drawn to a Sn-plated copper conductor having a square cross section using a deformed die, This is a manufacturing method in which a Sn-plated flat conductor is formed by rolling. Since the Sn plating flat conductor manufactured by such a process has a uniform and thin Sn plating layer, it is possible to suppress the generation of whiskers even when used for a long time by fitting with a connector. Further, since the Sn plating layer is sufficiently thin, it is advantageous in terms of manufacturing cost. The manufacturing process is performed in the same manner as the manufacturing process of the Ni-plated rectangular conductor described above. That is, as shown in FIG. Specifically, an Sn plated copper wire drawn to a predetermined diameter is used, and a copper round wire is usually one having a diameter of about 0.8 mm and a Sn plating layer of about 5 to 20 μm. Also, the odd-shaped die having a rectangular hole portion to be drawn before rolling is also a rectangular die having a hole portion of about 0.07 to 0.18 mm in length and a width of about 0.09 to 0.2 mm. Used. The quadrangle is usually a square or a rectangle, but a rectangle is particularly preferable, and a surface reduction process of about 0.1% is usually performed in this step. By passing such a deformed die and drawing, a rectangular conductor having a uniform and thin Sn plating layer can be obtained without the above-described problems even if a normal rolling process is performed thereafter. Specifically, it is possible to obtain an Sn-plated rectangular conductor in which the ratio between the maximum value and the minimum value of the plating layer thickness is 1.05 or less.

  And when FFC is manufactured using the above-mentioned Sn-plated flat conductor, the Sn-plated flat conductor is a flat conductor having a uniform and thin Sn-plated layer. The acicular crystal called does not grow. For this reason, the FFC is practical without causing a short circuit between copper wirings. Further, the obtained FFC has excellent bending characteristics.

The effects of the present invention will be described below by describing examples and comparative examples.
Example 1 An Ni plating layer having a thickness of 10 μm was formed on an annealed copper round wire of Φ0.8 mm by electrolytic Ni plating. This Ni-plated annealed copper round wire was drawn to Φ0.12 mm by wire drawing. Then, using a deformed die having a rectangular hole having a vertical length of 0.095 mm and a horizontal width of 0.119 mm, the Ni-plated copper wire having a rectangular cross section was drawn. Further, this Ni-plated copper wire having a rectangular cross section was rolled using upper and lower rolling rolls to obtain a Ni-plated rectangular conductor having a thickness of 0.035 mm. Five were produced as examples. As a comparative example, the above-mentioned Φ0.12 mm Ni-plated annealed copper round wire was similarly rolled to form a 0.035 mm Ni-plated rectangular conductor. Three were produced as comparative examples. Further, as a comparative example, the lower rolling roll of the above-described Ni-rolled annealed copper round wire having a diameter of 0.12 mm is a rolling method proposed by the present inventors (see Japanese Patent Application Laid-Open No. 2007-95633). Rolling was performed by a method of rapid repetitive movement in the direction crossing the rotation axis direction. Three were produced as comparative examples. These samples were cut at appropriate positions in the longitudinal direction, and the maximum value and the minimum value of the thickness of the Ni plating layer were measured from the cross-sectional observation. The results are shown in Table 1 as the ratio (A / B) between the maximum value (A) and the minimum value (B).

  As is apparent from Table 1, the thickness of the plating layer is the maximum value and the minimum value of the one using a deformed die having a rectangular hole as in Examples 1 to 5 of the present invention which is an example of Ni plating. It is uniform with a value ratio of 1.05 or less. On the other hand, in Comparative Examples 1 to 3, which are examples of rolling methods that are generally performed in the past, there is a large difference between the maximum value and the minimum value ratio of 13.9 to 19.0. Further, in Comparative Examples 4 to 6 which are examples of the rolling method proposed by the present inventors, the ratio of the maximum value to the minimum value was 1.20 to 1.32, which was not sufficiently uniform.

  Example 2: An Ni plating layer having a thickness of 10 μm was formed on an annealed copper round wire of Φ0.8 mm by electrolytic Ni plating. This Ni-plated annealed copper round wire was drawn to Φ0.12 mm by wire drawing. Subsequently, using a deformed die having a substantially square hole of 0.105 mm square, the Ni-plated copper wire having a rectangular cross section was drawn. Further, this Ni-plated copper wire having a rectangular cross section was rolled using upper and lower rolling rolls, and five Ni-plated rectangular conductors having a thickness of 0.035 mm were produced. As a comparative example, the above-mentioned Φ0.12 mm Ni-plated annealed copper round wire was similarly rolled to form a 0.035 mm Ni-plated rectangular conductor. (Production of 3). As Comparative Examples, Comparative Examples 1 to 6 described in Example 1 were cited. These samples were cut at appropriate positions in the longitudinal direction, and the maximum value and the minimum value of the Ni plating layer thickness were measured from the cross-sectional observation. The results are shown in Table 2 as the ratio (A / B) between the maximum value (A) and the minimum value (B).

  In addition, as is apparent from Table 2, the thickness of the plating layer is a ratio between the maximum value and the minimum value when using the irregular dies having substantially square holes shown in Examples 6 to 10 of the present invention. It is uniform as 1.05 or less. On the other hand, a large difference was observed in Comparative Examples 7 to 9, and the rolling methods of Comparative Examples 10 to 12 were not sufficiently uniform.

  Example 3 An Sn plating layer having a thickness of 10 μm was formed on an annealed copper round wire of Φ0.8 mm by electrolytic Sn plating. This Sn plated annealed copper round wire was drawn to Φ0.12 mm by wire drawing. Subsequently, using a deformed die having a rectangular hole portion having a vertical length of 0.095 mm and a horizontal width of 0.119 mm, the wire was drawn into an Sn-plated copper wire having a rectangular cross section. Furthermore, this Sn-plated copper wire having a rectangular cross section was rolled using upper and lower rolling rolls, and five Sn-plated rectangular conductors having a thickness of 0.035 mm were produced. As a comparative example, the Φ0.12 mm Sn-plated annealed copper round wire was similarly rolled to obtain a 0.035 mm Sn-plated rectangular conductor. (Production of 3 wires) Further, as a comparative example, lower rolling, which is a rolling method proposed by the present inventors for the Sn-plated annealed copper round wire of Φ0.12 mm (see Japanese Patent Application Laid-Open No. 2007-95633). The roll was rolled by a method in which the roll was repeatedly moved quickly in a direction crossing the rotational axis direction of the upper rolling roll. (Three samples were produced.) These samples were cut at appropriate positions in the longitudinal direction, and the maximum value and the minimum value of the Sn plating layer thickness were measured from the cross-sectional observation. The results are shown in Table 3 as the ratio (A / B) between the maximum value (A) and the minimum value (B).

  As is apparent from Table 3, the thickness of the plating layer is 1 in the ratio between the maximum value and the minimum value when using the odd-shaped dies having the rectangular hole portions which are Examples 11 to 15 showing examples of Sn plating. .05 or less. On the other hand, in Comparative Examples 13-15 which are examples of the rolling method generally performed conventionally, the difference between the maximum value and the minimum value is 2.90-3.20, which is large. Also, in Comparative Examples 16 to 18 which are examples of the rolling method proposed by the present inventors, the ratio of the maximum value to the minimum value was 1.12 to 1.48, which was not sufficiently uniform. .

  Example 4 An Sn plating layer having a thickness of 10 μm was formed on an annealed copper round wire of Φ0.8 mm by electrolytic Sn plating. This Sn plated annealed copper round wire was drawn to Φ0.12 mm by wire drawing. Subsequently, the wire was drawn into an Sn-plated copper wire having a rectangular cross section using a deformed die having a substantially square hole of 0.105 mm square. Furthermore, this Sn-plated copper wire having a rectangular cross section was rolled using upper and lower rolling rolls, and five Sn-plated rectangular conductors having a thickness of 0.035 mm were produced. As a comparative example, the Φ0.12 mm Sn-plated annealed copper round wire was similarly rolled to obtain a 0.035 mm Sn-plated rectangular conductor. (Production of 3). As Comparative Examples, Comparative Examples 13 to 18 described in Example 3 were cited. These samples were cut at appropriate positions in the longitudinal direction, and the maximum value and the minimum value of the Sn plating layer thickness were measured from the cross-sectional observation. The results are shown in Table 4 as the ratio (A / B) between the maximum value (A) and the minimum value (B).

  Further, as apparent from Table 4, in the examples using the irregular dies having substantially square holes shown in Examples 16 to 20, the thickness of the plating layer is 1.05 in a ratio between the maximum value and the minimum value. It is uniform with the following. On the other hand, a big difference was seen in Comparative Examples 19-21, and it could not be said that the rolling methods of Comparative Examples 22-24 were sufficiently uniform.

  Since the FFC of the present invention uses a plated flat copper conductor with a more uniform plating layer thickness, the plated flat conductor is excellent in corrosion resistance, and in the FFC using the Sn plated flat conductor, Since whisker is not generated when it is attached to a terminal of a connector, it is useful without causing a short circuit between copper wirings during use in equipment.

It is process drawing which shows the outline of the manufacturing process of the plating flat conductor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plating soft copper round wire drawn to predetermined diameter 2 Round copper wire 3 Plating layer 4 Deformed die 5 Plating copper conductor with square cross section 6 Plating rectangular conductor

Claims (4)

  Nickel-plated round copper wire drawn to a predetermined diameter is drawn into a nickel-plated copper wire with a square cross section using a deformed die, and this is plated into a rectangular conductor by rolling. Manufacturing method of flat copper conductor.   A plurality of nickel-plated rectangular copper conductors obtained by the manufacturing method according to claim 1 are laminated in parallel by an insulating tape with an adhesive at a necessary interval, and a connection portion is formed at an end thereof. A flexible flat cable characterized by being made.   A tin-plated round copper wire drawn to a predetermined diameter is drawn into a tin-plated copper wire having a square cross section using a deformed die, and this is used to produce a flat conductor by rolling. Manufacturing method of flat copper conductor.   A plurality of tin-plated rectangular copper conductors obtained by the manufacturing method according to claim 3 are laminated in parallel by an insulating tape with an adhesive at a necessary interval, and a connecting portion is formed at an end thereof. A flexible flat cable characterized by being made.