JPH0353381Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Technical field of invention] The present invention relates to a water running prevention type cable.

[Technical background of the invention and its problems] In general, a water running prevention type cable is made of multiple insulated wire cores 1, 1, 1, . . . as shown in Fig. 1.
A structure in which a laminated metal tape 5 and a plastic sheath 6 are sequentially applied on a cable core 4 in which a jelly-like mixture 2 is filled in the gap between the cable cores and a pressure tape 3 is wound on the outside of the cable core 4 is widely used. There is.

However, in a water running prevention type cable having such a structure, water running inside the cable core 4 is prevented by filling it with a jelly-like mixture 2 such as polybutene or petrolatum, and the laminated metal tape 5 and the plastic sheath 6 is also prevented because the molded outer diameter of the laminated metal tape 5 is made almost constant using a drawing die. It has the disadvantage of being difficult.

That is, the jelly-like mixture 2 is melted at around 100° C. and filled between the insulated wire cores 1, and is cooled to room temperature and solidified, but the volume shrinks by several percent during this solidification. Therefore, the solidified jelly-like mixture 2 is peeled off from the inner surface of the laminated metal tape 5, and a continuous gap is created in the longitudinal direction of the cable.

In addition, in a communication cable, since the outer diameter of the cable core 4 is not constant, a gap is created between the presser tape 3 and the laminated metal tape 5, which causes water to run between the presser wrap tape 3 and the laminated metal tape 5. be.

Therefore, if the cable is damaged and water floods into the cable core 4, there is a risk that the gap between the cable core 4 and the laminated metal tape 5 will become a water passage, especially since the surface of the laminated metal tape 5 is smooth. , there was a problem that it became easier to run on water.

In order to solve these problems, proposals have been made for cables in which an excessive amount of jelly-like mixture is applied onto the pressure tape, and a cable is provided with a hygroscopic swelling layer made of a material that absorbs water when water enters the cable.

However, in the former case, when the ends of the laminated metal tape are fused, there is a risk that the jelly-like mixture may leak from the seam and cause defective fusion, and in the latter case, although it has the effect of retarding the intrusion of water from the outside of the sheath, However, it has not been possible to completely prevent water running.

[Purpose of the invention] The present invention was made in order to eliminate such conventional drawbacks, and aims to eliminate the gap between the presser tape and the laminated metal tape to provide a complete cable that prevents water from running.

[Summary of the invention] In other words, the anti-water run cable of the invention has a cable core made of multiple insulated wire cores with a
In a water running prevention type cable in which a presser tape, a laminated metal tape, and a plastic sheath are sequentially applied, and a jelly-like mixture is filled in the gap between the insulated wire cores, the presser wrap tape and the laminated metal tape In between, on the base tape
It is characterized by interposing a thermally foamable tape provided with a thermally foamable microcapsule layer that foams at a temperature of 110°C or higher.

Plastic tape is suitable as the base tape used for the thermally foamable tape of the present invention.
In particular, plastic tapes with excellent heat resistance and mechanical properties, such as polyester tapes, are suitable.

In addition, the thermally foamable microcapsules that are attached to this base tape in a layered manner are thermoplastic resin microcapsules that contain a foaming agent, and do not foam at temperatures of 60°C to 100°C when filling the jelly-like mixture. , a material that foams at a temperature of 110°C or higher during sheath extrusion is used.

As a commercial product of such heat-expandable microcapsules, Matsumoto Microsphere F-50 is available.
(trade name, manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.). Matsumoto Microsphere F-50 is a thermally foamable microcapsule containing low-boiling point hydrocarbons, has a particle size of 10 to 20 μm, does not foam at temperatures below 100°C,
It foams at temperatures above ℃ and has a maximum expansion ratio of approximately 20 times.

Matsumoto Microsphere F-50 has excellent chemical resistance and solvent resistance, and also has good resistance to jelly-like mixtures.

The heat-foamable tape used in the present invention is, for example, an acrylic emulsion in which Matsumoto Microsphere F-50 is suspended together with an adhesive, which is uniformly applied to one or both sides of a polyester film, and then dried. A material on which a thermally foamed layer of about 40 μm is formed can be used.

In addition, if the coating amount of Matsumoto Microsphere F-50 is less than 6 g/ ^m2 , a foam layer with sufficient thickness cannot be obtained, and if it is too large, it becomes uneconomical, so the coating amount should be 6 to 15 g/m2. A range of m ² is suitable.

[Embodiment of the invention] An embodiment of the invention will be described below based on the drawings.

FIG. 2 is a sectional view of an embodiment of the anti-water running cable of the present invention, showing a state in which the thermally foamable tape 11 is foamed by the heat generated during extrusion of the sheath.

In FIG. 2, reference numeral 12 denotes an insulated wire core 1 made of a conductor such as copper or aluminum with a plastic insulator.
A plurality of insulated wire cores 13, 13, 13... are twisted together, and a jelly-like mixture 14 is filled between these insulated wire cores 13, 13, 13... to maintain a circular cross-sectional shape. A cable core formed by winding a presser tape 15 is shown.

On the outer periphery of the presser tape 15, a thermally foamable tape 11, in which a thermally foamed layer 11b made of the aforementioned thermally foamable microcapsules is formed on one side on a polyester tape 11a, is attached vertically with the thermally foamed layer 11b facing outward. There is. The thermally foamed layer 11b of this thermally foamable tape 11 is foamed by a method described below.

Furthermore, a laminated metal tape 16 is vertically attached to the outside of this heat-foamable tape 11 with the plastic surface facing outward, and the ends of the tape are overlapped and fused. 17 is a plastic sheath extrusion coated as the outermost layer.

This cable is manufactured as follows.

First, a plurality of insulated wire cores 13 are twisted together,
A jelly-like mixture 14 is filled between the insulated wire cores 13, and a pressing tape 15 is further wound around the outer periphery of the jelly-like mixture 14 to produce a cable core 12.

Next, a thermally foamable tape 11 is applied vertically to the outer periphery with the thermally foamed layer 11b facing outward, and a laminated metal tape 16 is further applied vertically to the outer periphery with the plastic surface facing outward.

Thereafter, plastic molten at about 170 DEG C. to 240 DEG C. is extruded onto the outermost layer to form a plastic sheath 17.

At this time, the plastic layers at the overlapping portions of the laminated metal tape 16 are first melted and fused together due to heat transfer from the plastic sheath 17 side.
Then, the thermally foamable microcapsules of the thermally foamable layer 11b start foaming.

After being extruded and coated with the plastic sheath 17, the jelly-like mixture 14 receives heat from the insulated wire core 13 and begins to solidify, causing it to shrink.
Since the thermally foamable microcapsules 1 foam and expand to press the pressure tape 15, no voids are created between the jelly-like mixture and the laminated metal tape 16.

The waterproof properties of the anti-water running cable formed in this way are as specified by the REA Act (water pressure 0.915
m, 0.915 after pressurizing for 1 hour at a temperature of 23±2℃
(no water leakage at the end of the cable) and
Standards based on BPO method (water pressure 1m, temperature 20±5℃,
It has characteristics that pass the test (no water leaking from the 3m cable end after 24 hours of pressurization).

In addition, although the above embodiment is an example in which the thermally foamable tape 11 is vertically attached with the thermally foamed layer 11b facing outward, the same effect can be obtained even if the thermally foamed tape 11 is vertically applied with the thermally foamed layer 11b facing inward. The effect of this can be obtained.

[Effects of the invention] As explained above, according to the anti-water running cable of the invention, the gap between the presser tape and the laminated metal tape is filled with heat-foamable material on the base tape at a temperature of 110°C or higher. Since it can be completely filled with the heat-foamable tape provided with the microcapsule layer, water running inside the cable can be completely prevented.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional anti-water running cable.
FIG. 2 is a sectional view of an embodiment of the anti-water running cable according to the present invention. DESCRIPTION OF SYMBOLS 11... Heat foamable tape, 11a... Polyester tape, 11b... Heat foam layer, 12... Cable core, 13... Insulated wire core, 14... Jelly-like mixture, 15... Pressure winding tape, 16 ... Laminated metal tape, 17 ... Plastic sheath.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A cable core consisting of a plurality of insulated wire cores is covered with a pressing tape, a laminated metal tape, and a plastic sheath in this order, and the gaps between the insulated wire cores are In a water running prevention type cable filled with a jelly-like mixture, a thermally foamable microcapsule layer that foams at a temperature of 110° C. or higher is provided on the base tape between the presser tape and the laminated metal tape. A water running prevention type cable characterized by interposing a thermally foamable tape. (2) The anti-water running cable according to claim 1, wherein the base tape is a plastic film. (3) The anti-water running cable according to claim 1 or 2, wherein the thermally foamable microcapsule is a microcapsule containing a low boiling point hydrocarbon. (4) The amount of heat-expandable microcapsules applied is 6
g/m ² to 15 g/m ² The anti-water running cable according to any one of claims 1 to 3 of the utility model registration claims.