JP3997681B2 - Flat cable and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is, for example, home video, relates flat cable and a manufacturing method thereof that is used as a wiring material such as a printer.
[0002]
[Prior art]
A flat cable is generally a thin wire conductor that is sandwiched between a pair of insulating sheets and heated to apply pressure while being fused, and is used as a wiring material for home video and printers. It has been. An insulating sheet used for such a flat cable is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-116755, and the insulating sheet disclosed in this publication includes a base material such as polyethylene terephthalate (PET), polyvinyl chloride (hereinafter referred to as “polyethylene chloride”). Insulating sheet using a combination of PET and adhesive layer made of resin, polyester adhesive, etc., and using PVC resin as the adhesive layer, the material cost and processing Since the cost is low and the PVC resin is not bonded to the conductor, it is widely used because the insulating layer can be easily drawn or peeled off at the terminal.
[0003]
[Problems to be solved by the invention]
By the way, in recent years, flat cables have been required to be thinner and have a narrower conductor pitch (higher wiring density), and accordingly, the conductor has a small thickness and a narrow width (that is, a small cross-sectional area). ), And specifically, a conductor having a cross-sectional area of 0.01 mm ² or less is used.
[0004]
However, when a flat cable is manufactured using the insulating sheet described in the above-mentioned conventional publication, if the conductor cross-sectional area becomes small as described above, the conductor that breaks when the insulating layer is pulled out at the end of the flat cable. There was a problem that the ratio increased.
[0005]
Therefore, the present invention provides an insulating sheet for flat cable, a flat cable, and a method for manufacturing the same, which can sufficiently prevent a conductor breakage during drawing of an insulating layer at the end of the flat cable even when a conductor having a small cross-sectional area is used. The purpose is to provide.
[0006]
[Means for Solving the Problems]
The present inventors diligently studied to solve the above problems. As a result, it was found that the disconnection of the conductor is sufficiently prevented by setting the thickness of the PVC layer to a predetermined value or less, and the present invention has been completed.
[0007]
Sunawa Chi flat cable of the present invention is a flat cable comprising at least one linear conductor, and an insulating layer consisting of a pair of the insulating sheet, the linear conductor is 0.003 mm ² or more 0.00665mm Having a cross-sectional area of ² or less, the insulating sheet comprises a polyvinyl chloride (PVC) resin layer for fixing the linear conductor, and a sheet-like base material for supporting the polyvinyl chloride resin layer, The polyvinyl chloride resin layer has a thickness of 12 μm or more and 30 μm or less, and the insulating layer sandwiches the linear conductor between the polyvinyl chloride resin layers of the pair of insulating sheets, and the pair of insulating sheets applying pressure while heating, characterized and Turkey, such by fusing.
[0008]
Flat cable of the present invention, a linear conductor of flat cable, a small cross-sectional area (0.01 mm ² or less) even when using a conductor, disconnection of the linear conductor when pulling the insulating layer in the end processing of the flat cable Can be sufficiently prevented.
[0009]
The flat cable manufacturing method of the present invention is a flat cable manufacturing method including at least one linear conductor and an insulating layer covering the linear conductor, and a sol containing PVC resin is used as a base material. The step of applying and drying the sol to obtain a pair of insulating sheets having a PVC resin layer on the substrate, and sandwiching the linear conductors between the respective PVC resin layers of the pair of insulating sheets, heated to fuse to form an insulating layer under pressure while, viewed including the step of obtaining a flat cable with the linear conductor and the insulating layer, the linear conductor, 0.003 mm ² or more 0.00665mm The polyvinyl chloride resin layer has a cross-sectional area of ² or less, and has a thickness of 12 μm to 30 μm .
[0010]
According to this manufacturing method, a PVC resin layer having a thickness of 45 μm or less can be formed on the substrate, and the thickness of the PVC resin layer is made uniform compared to the case where an insulating sheet is formed by an extrusion process. It is possible. Therefore, according to this manufacturing method, the above flat cable can be effectively manufactured.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0012]
FIG. 1 is a cross-sectional view showing an embodiment of a flat cable of the present invention. As shown in FIG. 1, the flat cable 10 has at least one linear conductor 2. Although the number of the linear conductors 2 is three in FIG. 1, it is appropriately selected according to the width of the flat cable 10. The number of the linear conductors 2 is usually 1-50. The cross-sectional shape of each linear conductor 2 is usually rectangular, but may be circular, square, or the like. The thickness of the linear conductor 2 is usually 0.010 to 0.150 mm, preferably 0.015 to 0.100 mm, and the width is usually 0.1 to 1.5 mm, preferably 0.15 to 1.27 mm. is there. Further the upper limit of the cross-sectional area of the linear conductor 2 is preferably from the viewpoint of the density of the wiring is 0.01 mm ^2, more preferably 0.009 mm ^2. On the other hand, the lower limit of the cross-sectional area of the linear conductor 2 normally is 0.002 mm ^2, preferably 0.003 mm ^2. When the lower limit of the cross-sectional area is less than 0.003 mm ² , when the insulating layer is pulled out by the end processing of the flat cable 10, the proportion of the linear conductor 2 that is disconnected tends to increase. As the linear conductor 2, for example, soft copper, phosphor bronze or the like is used. Of these, annealed copper is preferred from the viewpoint of cost.
[0013]
The linear conductor 2 is covered with an insulating layer 4. The insulating layer 4 includes a pair of insulating sheet portions 4a and 4b, and is formed by applying pressure and fusing the pair of insulating sheets while heating. The insulating sheet portions 4 a and 4 b include a sheet-like base material 6 and a PVC resin layer 8 provided on the base material 6.
[0014]
As a material constituting the substrate 6, for example, polyethylene terephthalate (PET) or polyimide is used. The thickness of the substrate 6 is usually 0.012 to 0.050 mm.
[0015]
The conductivity of the material constituting the PVC resin layer 8 is preferably 2.75 × 10 ⁻⁹ S / m or less. If the electrical conductivity exceeds 2.75 × 10 ⁻⁹ S / m, the insulation resistance of the flat cable 10 is too large, and it is unsuitable for use as wiring in electronic equipment. The PVC resin layer 8 having the above-described conductivity is formed by applying a PVC sol obtained by dissolving a PVC resin in a solvent to form a sol on the substrate 6 and then drying and volatilizing the solvent. Here, as the material constituting the PVC resin layer 8, a material having a softening point that can be deformed at a temperature at the time of fusion described later is used. As the solvent, for example, a plasticizer such as iodecyl phthalate or tri- (2-ethylhexyl) trimellitate is used, and among these, isodecyl phthalate is preferable.
[0016]
The content of the PVC resin in the PVC sol is preferably 20 to 50% by weight. When the content of the PVC resin is less than 20% by weight, the surface of the PVC resin layer 8 is sticky, and the insulation sheets or the insulation sheets and the equipment members that guide them adhere to each other when the insulation sheet is wound or supplied. When it exceeds 50% by weight, the PVC resin itself becomes hard, so that application to the substrate 6 becomes difficult. The content of the solvent in the PVC sol is preferably 50 to 80% by weight. If the content of the solvent is less than 50% by weight, the PVC resin itself becomes hard, so that application to the base material 6 tends to be difficult. If it exceeds 80% by weight, the surface of the PVC resin layer 8 becomes sticky, and the insulating sheet When winding in this state or supplying the insulating sheet, the insulating sheets or the insulating sheet adhere to the equipment member that guides the insulating sheet, making the operation difficult. The PVC sol may contain a stabilizer such as barium stearate, a filler such as aluminum silicate, and the like as necessary.
[0017]
The upper limit of the thickness of the PVC resin layer 8 is 45 μm, preferably 30 μm. This is because, when the upper limit of the thickness of the PVC resin layer 8 exceeds 45 μm, the linear conductor 2 moves in the insulating layer 4 when the insulating layer 4 is pulled out at the end of the flat cable 10. This is because the PVC resin layer 8 sandwiched between the layers becomes inhomogeneous, and the percentage of the linear conductors 2 that breaks increases due to a large force for fixing the linear conductors 2 locally. is there. On the other hand, the lower limit of the thickness of the PVC resin layer 8 is preferably 12 μm, and more preferably 15 μm. If the thickness of the PVC resin layer 8 is less than 15 μm, the amount of resin that wraps around both sides of the conductor 2 at the time of fusion is insufficient, so that a space is formed between both sides of the conductor 2 and the resin layer 8. Since the adhesive strength with the wire 4 becomes uneven, the individual conductors 2 move unevenly at the end face of the flat cable 10 by bending or twisting after cutting the end portion, making it difficult to connect to the terminal. If the thickness is less than 12 μm, the amount of wraparound of the resin at the time of fusing becomes insufficient, and sufficient pressure is not applied to the bonding surface between the resin layers 8. In some cases, the two insulating sheets may be peeled off after being molded into the flat cable 10.
[0018]
Next, a method for manufacturing the flat cable 10 will be described with reference to FIG. FIG. 2 is a series of process diagrams showing how the flat cable 10 is manufactured.
[0019]
First, a sheet-like substrate 6 is prepared. For example, PET is used as the substrate 6. On the other hand, a PVC sol 7 is prepared. The PVC sol 7 is obtained by dissolving a PVC resin in a solvent to form a sol, and as the solvent, for example, a plasticizer is used. The PVC sol 7 may further contain a stabilizer, a filler and the like as necessary.
[0020]
And the PVC sol 7 is apply | coated on the base material 6 (refer FIG. 2 (a)), the PVC sol 7 is heat-dried after that, and a solvent is volatilized (refer FIG.2 (b)). The PVC sol 7 is heated until the thickness of the PVC resin layer 8 on the substrate 6 becomes 45 μm or less. In this way, an insulating sheet 9a in which the PVC resin layer 8 is provided on the substrate 6 is obtained. Similarly, another sheet of insulating sheet 9b is prepared.
[0021]
Next, a plurality of linear conductors 2 are prepared, arranged in parallel at a predetermined pitch, and the plurality of linear conductors 2 are sandwiched between the PVC resin layers 8 of the pair of insulating sheets 9a and 9b prepared in advance (FIG. 2 (c)). Thereafter, the insulating sheets 9a and 9b are heated and melted by applying pressure from both sides (see FIG. 2D) to obtain the insulating layer 4 including the insulating sheet portions 4a and 4b. Thus, the flat cable 10 is obtained (see FIG. 1).
[0022]
The flat cable 10 can be manufactured in the same manner even when the number of the linear conductors 2 is one.
[0023]
Next, an example of the terminal processing method of the flat cable 10 will be described.
[0024]
As shown in FIG. 3A, the flat cable 10 is first placed on the base 12 and arranged so that its tip protrudes from the edge 12a of the base 12, and further flattened by the pressing member 14 from above the flat cable 10. The cable 10 is fixed. Next, the flat cable 10 is sandwiched from the upper and lower surfaces by the two blades 16 with respect to the protruding tip of the flat cable 10, and cuts are made in the base material 6 on both surfaces (see FIGS. 3B and 3C). Subsequently, the insulating layer 4 is removed by pulling the blade 16 toward the end face of the flat cable 10 (see FIG. 3D). The two blades 16 are adjusted so that the distance between the blade edges is the smallest and larger than the conductor thickness.
[0025]
At this time, for the flat cable 10, even when the linear conductor 2 having a small cross-sectional area (0.01 mm ² or less) is used, the disconnection can be sufficiently prevented. Accordingly, the wiring density can be improved in the flat cable 10.
[0026]
Next, the content of the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
[0027]
【Example】
Example 1
A PVC sol comprising 35% by weight of PVC resin, 62% by weight of diisodecyl phthalate as a plasticizer, and 3% by weight of barium stearate as a stabilizer and aluminum silicate as a filler was prepared.
[0028]
The PVC sol is coated on a polyethylene terephthalate resin tape having a thickness of 0.012 mm, and the tape is heated in an oven at 160 ° C. to volatilize about 1/3 of the plasticizer. Was dried until the thickness of the film was 0.02 mm (20 μm) and no fingerprint was formed even when touched with a finger to obtain an insulating sheet having a PVC resin layer formed on the tape. It was 170 degreeC when the softening point of the material which comprises this PVC resin layer was measured.
[0029]
Next, 20 linear conductors having a thickness of 0.035 mm and a width of 0.19 mm are juxtaposed at a pitch of 0.3 mm, insulating sheets are arranged above and below the linear conductors, and the insulating sheets are heated at 160 ° C. While being sandwiched between two rolls, pressure was applied and fused to form an insulating layer, and a flat cable was manufactured.
[0030]
The flat cable thus obtained was evaluated for various characteristics such as insulation resistance, withstand voltage characteristics, heat resistance test, environment resistance test, bending performance, and processing performance.
[0031]
The insulation resistance was determined as a ratio between a potential difference of 500 V between the linear conductors of two flat cables having a length of 1.5 m, and the potential difference and the leakage current generated in the insulating layer at this time. The insulation resistance was as good as 1000 MΩm or more.
[0032]
Withstand voltage characteristics: 3 flat cables with a length of 1.5m are juxtaposed, a 500V potential difference is applied between the linear conductors of adjacent flat cables in the air, and held for 1 minute. Evaluation was made by the presence or absence of dielectric breakdown when a potential difference of 1000 V was applied between the linear conductors of adjacent flat cables immersed in water and held for 1 minute. As a result, dielectric breakdown did not occur in the former case and the latter case. From this result, it was found that the flat cable has good withstand voltage characteristics.
[0033]
The heat resistance test was performed by examining the insulation resistance and withstand voltage characteristics of a flat cable left in an environment of 85 ° C. for 96 hours. As a result, no deterioration of the characteristics was observed in any case, and it was confirmed that the flat cable according to this example had good heat resistance.
[0034]
In the environmental resistance test, the flat cable was left in an environment of −40 ° C. for 4 hours, then left at 85 ° C. for 4 hours, and further left at 25 ° C. for 1 hour. This was done by examining the withstand voltage characteristics. As a result, no deterioration of these characteristics was observed. In addition, the insulation resistance and withstand voltage characteristics of the flat cable which was left in an environment of 95% relative humidity at 40 ° C. for 96 hours were examined. As a result, no deterioration of these characteristics was observed. From the above, it was confirmed that the flat cable according to the present example has good environmental resistance.
[0035]
Bending performance is as follows: For three flat cables, a mandrel with the same outer diameter as the thickness of each cable is brought into contact with the flat cable in the longitudinal direction of the linear conductor, and the flat cable is bent 180 ° around the mandrel. The operation was repeated 50 times, and the quality was determined based on the state of the flat cable at that time (that is, whether the conductor was disconnected or the insulating layer was peeled off). As a result, for any flat cable, no breakage was observed in all the conductors, and no peeling of the insulating layer was observed. From this, it was found that the flat cable according to the present example has good bending performance.
[0036]
The processing performance was judged as good or bad as follows. That is, the flat cable was first placed on the table, and the tip of the flat cable was arranged so as to protrude 20 mm from the edge of the table, and the flat cable was fixed with a pressing member from above the flat cable. Next, at a position 10 mm from the end face of the flat cable, the flat cable is sandwiched from the upper and lower sides with two blades, cut into the double-sided resin tape, and then insulated by pulling the blade toward the end face of the cable. Terminal processing to remove the layer was performed. Here, the two blades were adjusted so that the distance between the blade edges was the smallest and 50 μm, which was 15 μm larger than the conductor thickness (35 μm), and the conductor center line was located between the blade edge and the blade edge. Then, this terminal processing was performed on 20 flat cables, and the conductor breakage at this time was observed. If no breakage of the conductor was observed, it was determined that the processing performance was good, and if it was found, it was determined to be defective. . As a result, it was found that the insulation layer could be removed without any abnormality of conductor breakage for all 20 flat cables, and the terminal processing was easy.
[0037]
(Comparative Example 1)
A flat cable was prepared in the same manner as in Example 1 except that a 0.05 mm (50 μm) thick PVC resin layer was formed on the substrate. Various characteristics of the flat cable thus obtained were evaluated in the same manner as in Example 1. As a result, evaluation results equivalent to those of Example 1 were obtained except for the processing performance. However, regarding the processing performance, one or more conductors were broken in 18 of 20 flat cables. From this, it was found that it is difficult to use a conductor having such a small cross-sectional area and low strength as a conductor of a flat cable.
[0038]
(Comparative Example 2)
Although an attempt was made to form a PVC resin layer having a smaller thickness (30 μm) than the PVC resin layer of Comparative Example 1 by an extrusion method, the thickness of the extruded PVC resin layer was not uniform, and the insulating sheet itself It was not possible to manufacture and therefore a flat cable could not be manufactured.
[0039]
【The invention's effect】
As described above, according to the insulator for a flat cable, the flat cable, and the manufacturing method thereof according to the present invention, even when the conductor has a small cross-sectional area, the conductor is sufficiently prevented from being disconnected when the insulating layer is pulled out at the end of the flat cable. can do. For this reason, the wiring density of the conductor can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a flat cable of the present invention.
FIG. 2 is a series of process diagrams showing how the flat cable of FIG. 1 is manufactured.
3 is a series of process diagrams showing a state of terminal processing of the flat cable of FIG. 1. FIG.
[Explanation of symbols]
2 ... a plurality of linear conductors, 4 ... an insulating layer, 6 ... a substrate, 7 ... a sol, 8 ... a polyvinyl chloride layer, 9a, 9b ... an insulating sheet, 10 ... a flat cable.

Claims (4)

A flat cable comprising at least one linear conductor and an insulating layer made of a pair of insulating sheets,
The linear conductor has a cross-sectional area of 0.003 mm ² or more 0.00665Mm ² or less,
The insulating sheet includes a polyvinyl chloride resin layer that fixes the linear conductor, and a sheet-like base material that supports the polyvinyl chloride resin layer,
The polyvinyl chloride resin layer has a thickness of 12 μm or more and 30 μm or less,
The insulating layer, and wherein the respective poly sandwich the linear conductor with a vinyl chloride resin layer and a are fused by applying a pressure while heating the pair of insulating sheet Turkey of the pair of insulating sheet Flat cable. The flat cable according to claim 1, wherein the polyvinyl chloride resin layer has a thickness of 12 μm to 20 μm. A method for manufacturing a flat cable comprising at least one linear conductor and an insulating layer covering the linear conductor,
Applying a sol containing a polyvinyl chloride resin to a substrate, drying the sol, and obtaining a pair of insulating sheets having a polyvinyl chloride resin layer on the substrate;
The linear conductor is sandwiched between the polyvinyl chloride resin layers of the pair of insulating sheets, and the insulating layer is formed by applying pressure while heating the pair of insulating sheets to form the insulating layer. And obtaining a flat cable provided with the insulating layer;
Only including,
The linear conductor has a cross-sectional area of 0.003 mm ² or more 0.00665Mm ² or less, the polyvinyl chloride resin layer is characterized <br/> having a thickness of 30μm or more 12μm Flat Cable manufacturing method. The flat cable manufacturing method according to claim 3, wherein the polyvinyl chloride resin layer has a thickness of 12 μm to 20 μm.

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