JP2012252815A - Coaxial cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coaxial cable exhibiting excellent terminal workability using YAG laser.SOLUTION: In the coaxial cable having a dielectric, an outer conductor, and a jacket formed sequentially on the outer circumference of an inner conductor, the dielectric consists of fluororesin and a pigment, and the pigment contains 1-10 wt% of carbon black, 80-95 wt% of a titanium oxide, and 1-10 wt% of a mixture of a copper oxide, a manganese oxide, a cobalt oxide and an aluminum oxide.

Description

  The present invention relates to a coaxial cable excellent in terminal processability using a YAG laser.

  In recent years, information communication devices represented by mobile phones have been remarkably advanced in technology such as high speed, large capacity, multiple functions, high image quality, etc. Coaxial cables used in these devices are being made finer.

Usually, a plurality of such micro coaxial cables are bundled and arranged in parallel, and an electrical connector is connected thereto. As a pre-processing step for connecting to an electrical connector, a coaxial cable is subjected to terminal processing using a CO ₂ laser, YAG laser, or the like, but in a very fine coaxial cable with a cable outer diameter of 0.3 mm or less, the thickness of the processed part Moreover, since it is thin, it may be damaged to peripheral parts other than a to-be-processed part.

In order to solve this problem, in the shielded cable of Patent Document 1, it is described that carbon black is added to the resin composition. However, with carbon black alone, as pointed out in Patent Document 2, there remains room for improvement such as poor voltage resistance. In particular, when the dielectric is thin, such as 40 μm or less, the withstand voltage tends to be reduced due to the influence of laser light absorption.
On the other hand, in Patent Document 2, damage due to YAG laser is reduced by adding titanium oxide instead of carbon black. In addition to titanium oxide, a coloring pigment is kneaded to enable coloring. However, since colored pigments usually contain a plurality of metals, the absorption and reflectance of laser light change, which affects properties such as terminal processability and voltage resistance, but it is unknown because there is no detailed description. It was.

Japanese Patent No. 4352935 JP 2007-234574 A

"THERMOHPHYSICAL PROPERITES OF MATTER The TPRC Data Series Volume 8. Thermal Radial Properties-Nonmetallic Solids", 1972

Therefore, the problem of the present invention is that, in the end processing of a coaxial cable using a YAG laser, other than the outer conductor which is a processed part, for example, the inner conductor and the dielectric are not damaged, and the end workability and the end processing after the end processing are performed. The object is to provide a coaxial cable excellent in voltage resistance.

According to the present invention, a coaxial cable in which a dielectric, an outer conductor, and a jacket are sequentially formed on the outer periphery of an inner conductor, the dielectric is made of a fluororesin and a pigment, and the pigment contains 1 to 10 wt% of carbon black. 80-95 wt% of titanium oxide, mixed oxide of copper oxide, manganese oxide, cobalt oxide and aluminum oxide (hereinafter referred to as copper-manganese-cobalt-aluminum oxide) 1 to 10 wt%.
As the fluororesin, a tetrafluoroperfluoroalkyl vinyl ether copolymer is preferably used, and the dielectric coating thickness is set to 0.20 mm or less.

According to the present invention adopting the above-described configuration, a coaxial excellent in terminal processability and withstand voltage after terminal processing without damaging the inner conductor and the dielectric, for example, other than the outer conductor which is a processed part by the YAG laser. You can get a cable.
The present invention will be described below with reference to the accompanying drawings.

It is sectional drawing of the coaxial cable of this invention. It is sectional drawing of the cable which arranged the coaxial cable of this invention in parallel.

The present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of the coaxial cable of the present invention. As shown in FIG. 1, a coaxial cable 1 in which a dielectric 3, an outer conductor 4, and a jacket 5 are sequentially formed on the outer periphery of an inner conductor 2.
FIG. 2 is a cross-sectional view of a cable in which coaxial cables of the present invention are arranged in parallel. As shown in FIG. 2, a coaxial cable 1 is arranged in parallel and is a cable 6 to which a fixing tape 7 is applied.
A feature of the present invention is the content of the pigment in the dielectric 3.
The dielectric 3 is made of a fluororesin and a pigment, and the pigment contains 1 to 10 wt% of carbon black, 80 to 95 wt% of oxide of titanium, and 1 to 10 wt% of copper-manganese-cobalt-aluminum oxide. .

Below, the content of various pigments and the mechanism of terminal processability will be described in more detail.
The wavelength of the YAG laser light is 1064 nm. The absorption, reflectance, and transmittance of various metal oxides contained in the pigment at the wavelength of 1064 nm are extracted from Non-Patent Document 1 and shown in Table 1. The symbol-means that there is no data description in the literature.

As shown in Table 1, since carbon black absorbs almost 100% of the laser beam, it suppresses the transmission of the laser beam from the dielectric 3 to the inner conductor 2, but there is a concern that the dielectric 3 itself is damaged if the content is large. Is done. Moreover, when there is much content, there exists a concern about the influence on electrical characteristics, such as extrusion moldability and attenuation amount.
Titanium oxide reflects the laser beam, so that damage to the dielectric 3 can be suppressed. However, there is a slight transmission, and there is a concern about damage to the internal conductor. Moreover, when there is much content, as above-mentioned, there exists a concern about the influence on extrusion moldability and an electrical property.
As a metal oxide having a high reflectance, alumina can be used in addition to titanium oxide. On the other hand, the absorption rate is markedly higher for carbon black and slightly higher for cobalt oxide.

In the present invention, as a pigment, an oxide obtained by mixing carbon black and various metal oxides was used, and as a result of specifying a pigment having excellent terminal processability, 1 to 10 wt% of carbon black and an oxide of titanium were used. 80 to 95 wt%, and 1 to 10 wt% of copper-manganese-cobalt-aluminum oxide has been reached. The copper-manganese-cobalt-aluminum oxide used in the present invention is a copper oxide of 15 to 35 wt%, a manganese oxide of 10 to 30 wt%, a cobalt oxide of 25 to 45 wt%, and an aluminum oxide. It is an oxide mixed with 10 to 30 wt%. These oxides may be used after high-temperature firing. The pigment is preferably contained in an amount of 0.1 to 6.0 wt% with respect to 100 wt% of the dielectric.
By adjusting the content of various metal oxides, the balance of the absorption, reflection, and transmission of the wavelength of the YAG laser light to the dielectric is adjusted, and for example, to the inner conductor or dielectric other than the outer conductor that is the workpiece Can be prevented, and the terminal processability and the withstand voltage after terminal processing can be improved.

By applying this, by adjusting the ratio of the pigment content, the choice of pigments can be expanded, and a coaxial cable excellent in terminal processability, voltage resistance and extrusion moldability can be obtained. In addition, since the withstand voltage is improved, the setting range of the laser light intensity can be widened, so that the productivity is improved, and further, the terminal processing can be performed without problems even when the thickness of the dielectric is thin, Effects such as increased cable size and structure options can be obtained.

Examples of the coaxial cable of the present invention are shown below.
"Examples 1-3, Comparative Examples 1-11"
As the inner conductor 2, a PFA thickness of 0.03 mm is applied as the dielectric 3 on the outer periphery of seven silver alloy tin-containing copper alloy wires / 0.021 mm (φ0.063 mm). Table 2 shows the types and contents of the pigments contained in the dielectric. Further, the outer conductor 4 is subjected to a horizontal winding of tin-plated tin-containing copper alloy wire φ0.025 mm, and the jacket 5 is subjected to a PFA thickness of 0.03 mm.

Table 3 shows the results of evaluating the coaxial cables of “Examples 1 to 3 and Comparative Examples 1 to 11” in order to confirm the effects of the present invention.
The evaluation contents were a damage confirmation of the inner conductor and the dielectric with a microscope (magnification × 100), and a withstand voltage test at a withstand voltage of AC 250 V (for 1 minute).
As a result, when copper-manganese-cobalt-aluminum oxide was used as a calcined pigment, it was confirmed that there was no damage or dielectric breakdown of the inner conductor and dielectric, and the terminal processability was excellent ( Examples 1 to 3). Compared to the case of using only carbon black and titanium oxide alone, the inclusion of a copper-manganese-cobalt-aluminum oxide contributes particularly to the absorption by cobalt oxide. It is assumed that the reflections interfered with each other and the influence on the dielectric was suppressed to a low level.
On the other hand, in the case of only carbon black and only titanium oxide, it was confirmed that damage was particularly large (Comparative Examples 1 to 4). As a cause, in the case of the micro coaxial cable as in the example, carbon black or titanium oxide alone is affected by slight absorption / reflection of laser light, and it is considered that the internal conductor and the dielectric were damaged. When both carbon black and titanium oxide were included, damage was reduced, but dielectric breakdown still failed (Comparative Examples 5 and 6). In the case of iron-titanium-aluminum-based oxides, an effect due to large reflection was expected as seen in titanium oxide and alumina alone, but no improvement effect was seen (Comparative Examples 7 and 8). Similarly, in the case of the copper-chromium-manganese oxide, no improvement effect was observed (Comparative Examples 9 and 10). The copper-manganese-cobalt-aluminum oxide did not damage the inner conductor / dielectric and did not cause dielectric breakdown (Examples 1 to 3). However, when the content was increased, the dielectric was slightly damaged. And dielectric breakdown also occurred (Comparative Example 11).

The concept of absorption, reflection and transmission of laser light of various metal oxides described in the present invention can be applied to oxides by other combinations and so-called colored pigments.

DESCRIPTION OF SYMBOLS 1 Coaxial cable 2 Inner conductor 3 Dielectric body 4 Outer conductor 5 Jacket 6 Cable arranged in parallel 7 Fixing tape P Distance between coaxial cables

Claims (4)

A coaxial cable in which a dielectric, an outer conductor, and a jacket are sequentially formed on the outer periphery of an inner conductor, and the dielectric is made of a fluororesin and a pigment, and the pigment includes 1 to 10 wt% of carbon black and an oxide of titanium. A coaxial cable comprising 80 to 95 wt%, 1 to 10 wt% of a mixed oxide of copper oxide, manganese oxide, cobalt oxide and aluminum oxide. The coaxial cable according to claim 1, wherein the dielectric fluororesin is made of a tetrafluoroperfluoroalkyl vinyl ether copolymer and has a coating thickness of 0.20 µm or less. The coaxial cable according to claim 1 or 2, wherein a withstand voltage after terminal processing is AC250V (1 minute) or more.   The coaxial cable according to claim 1, wherein a plurality of coaxial cables are arranged in parallel, and a processed product thereof.