JP2585619B2 - Waterproof type cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a water running prevention type cable in which a jelly-like mixture is filled between insulated wires, and in particular, a large-size communication cable. The present invention relates to a water flow prevention type cable suitable for a vehicle.

(Prior Art) Conventionally, when a jacket is damaged, a jelly-like admixture is filled between insulated wires in order to prevent water from entering the damaged portion to prevent the damage from reaching the entire line. Water resistant cables are widely used. The jelly-like admixture to be filled in the cable for preventing water running is required to have various properties such as not adversely affecting the cable, having good heat resistance and cold resistance, and not impairing the flexibility of the cable. Examples of the admixture satisfying such conditions include a polybutene-based or petrolatum-based jelly-like admixture.

As a method of filling these jelly-like admixtures into a cable, a pipe filling method, a twist filling method, an immersion filling method and the like are currently roughly classified.
In any of these methods, in order to completely fill the gap between the insulated wires with the jelly-like mixture,
It is necessary that the viscosity of the jelly-like mixture at the time of filling is low. Therefore, the jelly-like mixture is heated at a predetermined temperature, for example, 10
It is filled after it has been heated and melted at around 0 ° C and its viscosity has sufficiently decreased.

In order to confirm whether or not the jelly-like mixture has been completely filled, for example, a test such as a water flow test in the REA standard is performed. This is to check whether water has flowed out at the other end of the cable after applying water pressure at 0.915m for 1 hour from one end of a 0.915m long cable. Treated as completely done. In this water passage test, the lower viscosity jelly-like admixture is more advantageous because it is easier to fill.

On the other hand, in the specification of the manufactured water-running prevention type cable, the jelly-like mixture is completely filled, and at the time of low temperature (for example, 60 to 70 ° C.), the viscosity of the jelly-like mixture is high. It is required that the water running prevention effect be exhibited without causing oil separation or the like when the cable is used. That is, it is necessary that the jelly-like mixture does not flow out or drip even when the cable is held vertically. As an index indicating the property of the jelly-like mixture, that is, the dropping property, for example, REA standard or N
A drop test in the TT standard is known. In the drop test in the REA standard, one end of a cable with a total length of 30.48 cm is stripped off, the cable core is exposed with a length of 7.62 cm, each wire is flared, and the tip is held vertically downward, The mixture is allowed to stand at a specified temperature (65 ± 1 ° C.) for 24 hours, and the presence or absence of outflow and dripping of the jelly mixture is examined.

In this drop test, a jelly-like mixture having higher viscosity and less likely to cause oil separation or the like is more advantageous.

As described above, the jelly-like admixture to be filled in the water-stop type cable is required to have a sufficiently low viscosity at the time of filling and to be easily filled, and to have a sufficiently high viscosity at the time of use so as not to cause oil separation or the like. . Further, in recent years, with the expansion of the range of use of the water-running prevention type cable, there is a tendency that it is required to pass a dripping test at a higher specified temperature, assuming more severe use conditions.

(Problems to be Solved by the Invention) By the way, among the above-mentioned jelly-like admixtures generally used conventionally, petrolatum-based jelly-like admixtures are:
Although it has the characteristics of being excellent in packing properties and being inexpensive due to its low viscosity, it has a drawback that oil separation easily occurs because its main components are mineral oil and wax. On the other hand, those using polybutene as a main component, or those obtained by adding a rubbery substance, an oil absorbing agent, etc. to them are also used,
These high viscosities have the advantage of being excellent in dropping properties, but have the disadvantage that they are inferior in filling properties and are generally expensive. Then, when filling is performed by melting at a high temperature in order to enhance the filling property, there is a risk that the insulator is damaged by heat at the time of filling.

As described above, it has been difficult to satisfy both the filling characteristics and the dropping characteristics in addition to the various characteristics conventionally required as the jelly-like admixture to be filled in the water-running prevention type cable. Such a problem rarely occurs in a cable having a twist number of 200 or less (outer diameter of the sheath is about 30 mm), but the problem becomes more serious as the cable diameter increases. Generally, a thick multi-pair cable forms a cable unit by concentrically twisting a predetermined number of insulated wire single wires, twisted pair wires, or quad twisted wires to form a cable unit, which is then assembled to form a unit type cable. Often taken. When filling the jelly-like mixture into such a cable, do not try to fill the jelly-like mixture all the way to the center of the assembly line core, but after filling the jelly-like mixture for each cable unit, Twisting,
At the same time as or after the twisting, the space between the units is filled with the jelly-like mixture, and a presser tape or the like is wound thereon to coat the outer layer. Nevertheless, when using a high-viscosity jelly-like admixture with good dripping properties, it is easy to cause insufficient filling, the water-through test tends to be rejected, and if a low-viscosity jelly-like admixture with good filling properties is used, There was a problem that the drop test was likely to fail. The cause is considered to be due to the jelly-like admixture existing in a lump between the cable units and under the sheath.

In addition, since the expansion rate of the material constituting the cable jacket and the jelly-like mixture are different, the jelly-like mixture under the press-winding tape close to the jacket before the jacket expands significantly at the test temperature of the drop test. Is greatly expanded and overflows,
At this time, a phenomenon in which the jelly-like admixture dripped sometimes occurred due to the kneading effect. This phenomenon is particularly remarkable in a thick multi-pair cable. Therefore, in such a cable, even if a jelly-like admixture having both excellent filling characteristics and dripping characteristics is used, it is difficult to completely prevent the above phenomenon when the cable is filled with the jelly-like admixture.

The present invention has been made in order to solve such a problem, and the water running prevention and the dripping test can be passed even with a thick multi-pair cable, and the water running prevention can be obtained relatively inexpensively. Its purpose is to provide a type cable.

[Constitution of the Invention] (Means for Solving the Problems) That is, in the present invention, a cable core formed by further assembling and twisting a plurality of wires of a cable unit having a plurality of insulated wires is coated. In the cable, the gap between the insulated wires in the cable unit is filled with the first jelly-like mixture, and the gap between the cable units in the cable core has a higher viscosity than the first jelly-like mixture. Characterized in that the second jelly-like admixture is filled.

The first jelly-like mixture used in the present invention is at 100 ° C.
Is a jelly mixture having a viscosity of 20 to 80 cSt at 120 ° C. and 10 to 40 cSt at 120 ° C. As such an admixture, there is, for example, a REA jelly admixture (JP jelly admixture 1P) having a property of passing a drop test of REA standard. Similarly, the second jelly-like admixture is 4 ° C at 100 ° C.
It is a jelly-like mixture having a viscosity of not less than 00 cSt and not less than 200 cSt at 120 ° C. Examples of such a jelly-like mixture include a rubber-like substance-added mixture obtained by adding 5 parts of butyl rubber and 10 parts of PE wax to 85 parts of the above-mentioned REA-based jelly-like mixture, or 90 parts of polybutene HV-300 equivalent to PE. A polybutene-based jelly-like admixture mixed with 10 parts of wax is exemplified.

(Operation) In the water-running prevention type cable of the present invention configured as described above, since each unit is filled with a low-viscosity jelly-like admixture, the space between the insulated wires is jelly-like without leaving any gap. Filled with admixture.

Also, since the high-viscosity jelly-like mixture is filled in the gap between the units under the press-winding tape, the jelly-like mixture under the press-winding tape is transmitted from the jacket at the test temperature of the drop test. Even when the temperature rises due to heat and expands, it is difficult to drip.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

Embodiment FIG. 1 is a longitudinal sectional view of a water running prevention type cable according to an embodiment of the present invention. Reference numeral 1 denotes a twisted pair wire made of an insulated wire core having a conductor diameter of 0.5 mm, which is twisted in units of 100 pairs to form a cable unit 2. The drawing shows a part of the 100 pairs of twisted pair wires 1. In the space between the insulated wires inside the unit 2, the first jelly-like mixture 3
REA petrolatum jelly-like mixture (JP jelly-like mixture 1P). Units 2 filled with such a jelly-like admixture are respectively 4 and 8 from the center.
Twenty and twelve pieces were twisted concentrically in layers. After filling a polybutene-based jelly-like mixture as the second jelly-like mixture 5 above and below the gap between the units and the press-winding tape 4, a laminate sheath 6 is applied, and 2400 pairs of water-running prevention type cables are provided. Obtained. The polymerization outer diameter was 80 mm, and the outer jacket diameter was 90 mm. The thus-obtained cable for preventing water running was able to completely pass the drop test of REA standard at 65 ± 1 ° C. for 24 hours.

Comparative Example Preventing water running in the same manner as in the Example, except that the same jelly-like petrolatum as the first jelly-like mixture (JP jelly-like mixture 1P) was filled as the second jelly-like mixture 5 Molded cable was manufactured.

A drop test of REA standard at 65 ± 1 ° C. for 24 hours was performed on the obtained water-streak prevention type cable. As a result, the jelly-like mixture was dropped between the units and from under the sheath, and the test was rejected.

[Effects of the Invention] As described above, according to the present invention, since the gap between the cable units below the holding tape is filled with the high-viscosity jelly-like admixture, even a multi-to-thick cable is used. Characteristics that completely pass the REA standard drop test are obtained. In addition, since the space between the insulated wires in the unit is filled with a low-viscosity, low-cost jelly-like admixture, it has excellent filling properties and excellent properties that easily pass the water-through test. A protected cable is obtained relatively inexpensively without the need for special equipment or technology. Furthermore, when filling high-viscosity jelly-like admixtures into the gaps between cable units, the jelly-like admixtures may be melted at a high temperature and used to enhance the filling property. Is already filled with the low-viscosity jelly-like admixture, there is no danger of damage to the insulating coating of the insulated wire core.

[Brief description of the drawings]

 The drawing is a longitudinal sectional view of one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Twisted wire 2 ... Cable unit 3 ... 1st jelly-like mixture (low viscosity) 4 ... Holding tape 5 ... 2nd jelly-like mixture (high viscosity) 6 ... Laminate sheath

Claims (4)

(57) [Claims] A cable comprising a plurality of insulated wire cores in which a plurality of insulated wire cores are further assembled and twisted to form a sheath on a cable core. The first jelly-like mixture is filled in the gap, and the second jelly-like mixture having a higher viscosity than the first jelly-like mixture is filled in the gap between the cable units in the cable core. Characteristic for preventing running water. 2. The first jelly-like mixture is heated at 100 ° C. for 2 hours.
0-80 cSt, having a viscosity of 10-40 cSt at 120 ° C .;
Jelly mixture at 400 ° C or more at 100 ° C, 120 ° C
2. The water-running prevention type cable according to claim 1, wherein the cable has a viscosity of 200 cSt or more. 3. The water-impervious type according to claim 1 or 2, wherein the first jelly-like mixture is a jelly-like mixture which passes a drop test of REA standard. cable. 4. The second jelly-like mixture is a mixture of a jelly-like mixture passing a drop test of REA standard and a rubber-like substance, or a polybutene-based jelly-like mixture. The water-running prevention type cable according to any one of claims 1 to 3.