JP2003007142A - Ultra-high-foamed insulating cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new ultra-high-foamed insulating cable whose foaming coefficient is 80% or more, being excellent in adhesion and concentricity. SOLUTION: Related to a foamed insulating cable where a formed insulator 2 is arranged around a conductor 1, the foamed insulator 2 is formed of the ultra-high-foamed body of ethylene tetrafluoride-perfluoro alkyl vinyl ethyl copolymer resin whose melt index is 30 or higher. Thus an ultra-high-foamed insulating cable is provided where the adhesion and concentricity between the conductor 1 and the foamed insulator 2 are not degraded even if the foaming coefficient is 80% or higher.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-high foam insulation cable suitable for electronic equipment, medical equipment products and the like.

[0002]

2. Description of the Related Art Conventionally, as an insulated cable used for communication equipment, precision electric equipment, medical electronic equipment, etc.,
Fluororesin foam insulation cables are used that have excellent flame retardancy, high signal transmission speed, and thin insulation coating.

For example, as a conventionally used foam insulation cable, a fluorocarbon gas is added to a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having a melt index (hereinafter, simply abbreviated as MI) of about 3.4. It is used by injecting in an extruder, foaming, and coating the same on a conductor.

[0004]

By the way, in recent years, with the miniaturization and high-density mounting of these devices, in order to transmit more information signals, the so-called ultra-high degree of foaming of the insulator is further increased. Foam insulated cables have been coveted.

However, the conventional tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (MI≈
In the case of 3.4), the foaming degree is about 65% at the limit,
When it is attempted to achieve a higher degree of foaming than this, as shown in FIG. 2, gas gathers around the conductor 1 and the insulator swells in a donut shape to deteriorate the adhesion and concentricity between the conductor 1 and the insulator 2. It causes inconvenience.

Therefore, the present invention has been devised in order to effectively solve such a problem, and its object is to have a foaming ratio of 80% or more and to have excellent adhesion and concentricity. It provides a new ultra-high foam insulation cable.

[0007]

In order to solve the above-mentioned problems, the present invention provides a foam insulation cable having a foam insulation around a conductor, as set forth in claim 1, in which the foam insulation is melted. The foam is formed of an ultra-high foam of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having a lump of 30 or more, and the foaming degree thereof is in accordance with Claim 2.
As shown in FIG.

As a result, even if the degree of foaming is greatly improved as compared with the conventional case, excellent transmission characteristics and the like can be exhibited without deteriorating the adhesion and concentricity between the conductor and the insulator.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment for carrying out the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of an ultra-high foam insulation cable according to the present invention.

As shown in the figure, this ultra-high foam insulation cable has a structure in which an ultra-high foam insulation 2 having a foaming rate of 80% or more is coated around a thin conductor 1 having an outer diameter of 1.0 mm or less. Has become.

This foamed insulation 2 is made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin as in the case of the conventional foamed insulation cable, but its MI is higher than that of the conventional one, and its MI is 30 or more. Used.

Therefore, in the ultra-high foam insulation cable of the present invention using the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having MI of 30 or more as the foam insulation 2 as described above, the foaming degree is increased. Even if it is 80% or more, as will be described later, the adhesiveness and concentricity between the conductor 1 and the insulator 2 are hardly deteriorated, and the transmission characteristics and the like, which are significantly superior to the conventional ones, can be exhibited.

The term "MI" as used in the present invention means, as conventionally defined, the number of grams of thermoplastic resin extruded at a temperature of 190 ° C. through a 0.0825 inch orifice under a load of 1260 g for 10 minutes. Say.

[0015]

Example 1 As shown in the column of Example 1 of Table 1 below, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having MI of 35 was used as a material for the insulator. In the same manner as in the prior art, a chlorofluorocarbon-based gas was injected into the extruder to foam, and a conductor having an outer diameter of 0.254 mm was covered to prepare a foam insulated cable.

Example 2 As shown in the column of Example 2 in Table 1 below, except that a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having MI of 32 was used as a material for the insulator, A foam insulated cable was produced in the same manner as in Example 1.

Comparative Example 1 As shown in the column of Comparative Example 1 in Table 1 below, except that a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having MI of 13 was used as a material for the insulator, A foam insulated cable was produced in the same manner as in Example 1.

Comparative Example 2 As shown in the column of Comparative Example 2 in Table 1 below, except that a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having MI of 7 was used as a material for the insulator, A foam insulated cable was produced in the same manner as in Example 1.

(Comparative Example 3) As shown in the column of Comparative Example 3 in Table 1 below, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having MI of 3.4 was used as a material for the insulator. Produced a foam insulated cable in the same manner as in Example 1.

[0020]

[Table 1]

Then, the foaming degree and the inner diameter of the insulator (FIG. 1) of the foamed insulated cables of Examples 1 and 2 and Comparative Examples 1 to 3 thus obtained were measured. As described above, in the foamed insulated cables of Examples 1 and 2 in which the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having MI of 30 or more was used as the material of the insulator, the foamed degree was 80% in both cases. Despite exceeding, the inner diameter of the insulator was 0.28 mm, 0.
The diameter was 29 mm, and there was almost no expansion with respect to the outer diameter of the conductor of 0.254 mm, and excellent adhesion and concentricity could be exhibited.

On the other hand, in the foamed insulated cables of Comparative Examples 1 to 3 in which the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having MI much less than 30, the high foaming ratio of 80% is obtained. Although the inner diameter of the insulator was 0.35 mm and 0.3, respectively.
It was 6 mm and 0.38 mm, and a large gap was formed between the conductor and the conductor, and the adhesion and the concentricity were remarkably reduced.

Furthermore, the extrusion speeds of Examples 1 and 2 according to the present invention can be more than 5 times those of Comparative Examples 1 to 3, and the working time required for extrusion coating can be greatly shortened. I was able to.

Further, as can be easily inferred from this result, when extruding with a conventional foaming degree (about 60%), it is possible to extrude at an extrusion speed about 10 times that of the conventional extrusion. .

[0025]

In summary, according to the present invention, since the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having MI of 30 or more is used as the foamed insulator,
It is possible to obtain a high-quality high-expansion insulated cable in which the adhesion to the conductor and the concentricity are not impaired even if the foaming degree is increased. Also,
Since the extrusion speed is increased, the work efficiency is greatly improved, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing an embodiment of an ultra-high foam insulation cable according to the present invention.

FIG. 2 is a conceptual diagram showing a state in which the degree of foaming of the insulator of the conventional high-foam insulated cable is forcibly improved.

[Explanation of symbols]

1 conductor 2 foam insulation

Continued front page    (72) Inventor Hiroshi Okuji             Hitachi, 1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture             Electric Wire Co., Ltd. Hidaka Factory (72) Inventor Masatsugu Yoshio             Hitachi, 1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture             Electric Wire Co., Ltd. Hidaka Factory (72) Inventor Seiichiro Tabuchi             Hitachi, 1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture             Electric Wire Co., Ltd. Hidaka Factory F-term (reference) 4F074 AA39A AB05 BA53 CA22                       DA02 DA48

Claims (2)

[Claims] 1. A foam insulation cable provided with a foam insulation around a conductor, wherein the foam insulation is an ultra-high foam of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin having a melt index of 30 or more. A super high foam insulation cable characterized by being formed. 2. A foamed insulated cable having a foamed insulation around a conductor, wherein the foamed insulation has a foaming degree of 80% or more.