JPS6375713A - Waterproof optical fiber cable and apparatus for producing said cable - Google Patents

Abstract

PURPOSE:To stop the infiltration of water to the local point and to obtain a cable having an excellent waterproof characteristic by coating PE oxide on a core wire or spacer, sticking water absorptive powder thereon and winding a water absorptive tape thereon. CONSTITUTION:A core is formed by coating the PE oxide film 6 on either of the spacer 2 or optical fiber core 1 and sticking the water absorptive powder 7 on the surface thereof. The water absorptive core retaining and winding tape 5' is wound on such core and is coated thereon with a cable sheath 4 by which the optical cable is formed. The PE oxide and water absorptive powder which are in the form of the thin films absorb and immobilize sea water and confine the infiltration of the water to the local point when the cable sheath 4 has a damage and the sea water or the like infiltrates the damaged part of the cable. The powder 7 is immobilized and has no possibility of dislodgment. The optical cable having the excellent waterproof characteristic is thus obtd.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a structure that locally prevents water from entering from the outside and prevents deterioration of the characteristics of the transmission medium when damage occurs to the outer sheath of a communication cable. The present invention relates to a waterproof optical fiber cable and its manufacturing device.

[Prior Art] When the jacket of an optical fiber cable is damaged and water is present around it, water enters the inside of the cable and travels in the longitudinal direction of the cable. This phenomenon is generally called water running phenomenon, water running, or water running. If this water travel exceeds a certain limit, when the water inside the cable freezes at low temperatures, force will be applied to the fiber at the end, increasing optical loss, reducing the strength of the optical fiber, and lowering the insulation of copper cables. As a result, the cable cannot be used for a long period of time (for example, 10 to 20 years).

[Problem to be Solved by the Invention 1] A conventional optical fiber cable has a structure as shown in FIG. In FIG. 3, 1 is a circular or tape-shaped optical fiber core, 2 is a slot-shaped spacer with a plurality of spiral grooves that holds the core 1, and 3 is a cable located at the center of this spacer 2. 4 is the outermost outer sheath, and 5 is a non-water-absorbing core pressing tape wound between the outer sheath 4 and the spacer 2.

If the jacket 4 of such a cable is damaged and flooded, the above-mentioned water running phenomenon occurs in the non-water-absorbing core pressing tape 5, the voids in the slot-shaped spacer 2, and the like.

■ As a conventional countermeasure against this water running phenomenon, polybutene, petrolatum,
A structure is known in which the water is stopped from running by filling it with a sherry-like material such as grease. Although such a conventional structure has excellent water running prevention properties, it not only requires an extrusion device for the filler to perform filling during cable manufacturing, but also has a slow extrusion speed of 5 m/min or less. Therefore, there was a drawback that the manufacturing time was increased.

In addition, although the above-mentioned sherry material has a water running prevention effect due to its viscosity, it is necessary to remove the sherry material from around the optical fiber core 1 when interconnecting cables. becomes.

■ In addition, when the optical fiber cable having the structure shown in Fig. 3 is filled with polybutene-based sherry, preparatory work for connecting the optical fibers, i.e., removal of the cable jacket 4 and core pressing tape 5, optical fiber cable It takes about 30-40 minutes to remove the sherry from inside. This operation time is two to three times longer than the approximately 15 minutes required for pre-preparation of cables without sherry filling.

■ As a water running prevention structure that does not cause the above problems, a method has been proposed in which the voids in the cable are filled with a material that swells when it absorbs water. Powders such as polyacrylic acid, carboxymethyl cellulose, and starch are known as materials, and these powders can be filled into the cable either in powder form or by coating and adhering them to a tape made of nonwoven fabric. are doing. In this case, if these powders are directly filled into the voids inside the cable, the powders are not directly fixed inside the cable, so vibrations during cable transportation will cause the powder to move inside the cable, resulting in long-term water running. No prevention effect can be obtained, and the powder may fall off during connection work, resulting in poor workability, and the powder may adhere to the end face of the optical fiber connector, leading to functional deterioration of the optical fiber.

For this reason, it is desirable that the water-absorbing material has a tape-like or string-like shape that can be easily accommodated within the cable, or if the water-absorbing material is a powder, it is preferably fixed to some extent so as not to move within the cable.

Therefore, in the optical fiber cable as shown in Figure 3,
It is preferable that the core holding tape 5 is a water-absorbing tape rather than a conventional non-water-absorbing tape, and the gap (spiral groove) of the slot-shaped spacer 2 is actually very small. Therefore, it is desirable to fill the gap with water-absorbing powder to fix the optical fiber core 1 and the spacer 2. Furthermore, in order to securely fix the water-absorbing powder, it is common sense to apply an adhesive to the slot-shaped spacer 2, the optical fiber core 1, etc., and then sprinkle the water-absorbing powder thereon.

However, water-absorbing powder has the following problems.

■ There are various types of water that can enter an optical fiber cable, such as fresh water and seawater, and waterproofing is required in all cases. Of these, only a few powders that absorb seawater have been commercialized. Examples include Kl Gel (trademark) and Sumikagel (trademark). but,
Experiments have shown that many commercially available water-absorbing powders are corroded by microorganisms contained in water and lose their waterproofing effect. An example of a powder material that absorbs seawater without being corroded by microorganisms contained in the water is polyethylene oxide powder, which is a nonionic water-absorbing material.

However, this water-absorbing material usually has a slow water-absorbing rate, and it takes about one hour or more to reach a nearly saturated water-absorbing state. As a waterproofing material for optical fiber cables, it is desirable that the water absorption rate be within 1 minute, so this polyethylene oxide powder was not suitable for waterproofing cables. Therefore, to date, no water-absorbing material has been found that uses water-absorbing powder to absorb seawater within about one minute and does not corrode.

However, a water-absorbing material in which polyethylene oxide is coated on acrylic water-absorbing fibers has recently been invented (Japanese Patent Application No. 61-030509). The water absorption rate of polyethylene oxide of this water absorption material is within about 1 minute. The reason for this fast water absorption rate is not yet clear, but it is thought that it is because the coating on acrylic water absorbent fibers creates a thin film, which increases the surface area for water absorption. This is because even if polyethylene oxide is applied to non-water-absorbing fibers, such as polyethylene terephthalate fibers, the water absorption rate increases.

However, as mentioned in the above section (■), fibers or tape-like materials coated with polyethylene oxide cannot be inserted into the cavity of the slot-shaped spacer 2 shown in FIG. could not be applied.

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to provide a waterproof optical fiber cable that solves the above-mentioned problem, has excellent waterproof properties against seawater, etc., and can be applied to minute voids such as slotted L-shaped spacers, and an apparatus for manufacturing the same. Our goal is to provide the following.

[Means for Solving the Problems] In order to achieve the above object, the waterproof optical fiber cable of the present invention includes an optical fiber core and a slot-shaped spacer having a groove for accommodating the optical fiber core. An optical fiber cable core formed by applying polyethylene oxide and adhering water-absorbing powder or water-absorbing short 4ft to the surface of the applied polyethylene oxide, and a water-absorbing core wound on the outside of the optical fiber cable core. It is characterized by comprising a pressure winding tape and a cable jacket coated on the outside of the core pressure winding tape.

In addition, the manufacturing apparatus of the present invention includes a protruding part for protruding an optical fiber coated wire and a slot-shaped spacer having a groove for storing the coated optical fiber, and a fiber coated wire and a slot-shaped spacer protruded by the protruding part. an application section that applies a polyethylene oxide solution to at least one of the two, and a winding section that is arranged after the application section and that winds the optical fiber core around the groove of the slot-shaped spacer to form an optical fiber cable core; An adhesion section that is arranged after the application section and attaches water-absorbing powder or water-absorbent short fibers to the surface of the applied polyethylene oxide, a drying section that removes the solvent in the polyethylene oxide solution remaining on the surface, and a drying section. a tape winding section which is arranged at a later stage and winds a water-absorbing core-pressing winding tape around the outer periphery of the optical fiber cable core after drying in the drying section;
The present invention is characterized in that it includes a jacket manufacturing section that forms a cable jacket on the outside of the core-pressing winding tape.

[Function] In the present invention, polyethylene oxide is applied to at least one of the slot-shaped spacer and the optical fiber core, and water-absorbing powder or water-absorbing short fibers are attached to the surface of the applied polyethylene oxide. A water-absorbing core-pressing tape is wrapped around the formed optical fiber cable core, and the cable jacket is coated on top of it, so seawater is absorbed by the thin polyethylene oxide film and water-absorbing powder inside the cable. It also absorbs water and ordinary water well, and since the water-absorbing powder is fixed, it does not fall off. Furthermore, since polyethylene oxide itself is used in place of adhesive, it is easy to manufacture, and has excellent waterproof properties against seawater, etc. Excellent waterproof fiber optic cables can be easily obtained.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a cross section of an embodiment of the waterproof optical fiber cable of the present invention.

In Fig. 1, numerals 1 to 4 are the same members as in the conventional example shown in Fig. 3, but 5' is a water-absorbent core pressing tape, which is made of water-absorbent material such as acrylic water-absorbent fibers or polyester chives. Powder, such as acrylic acid powder or short acrylic fibers, is attached to it. 6 is a polyethylene oxide coating film, and 7 is a water-absorbing powder such as acrylate powder or acrylic water-absorbing fiber. Apply a polyethylene oxide solution prepared by dissolving polyethylene oxide in a solvent such as toluene or xylene around at least one of the slot-shaped spacer 2 and the optical fiber core (including the tape-shaped optical fiber core) 1. A polyethylene oxide coating film 6 is formed, water-absorbent powder 7 is adhered to almost the entire surface of the polyethylene oxide-coated layer 6 to create a water-absorbent optical fiber cable core, and the water-absorbent core is wrapped around the core. A cable jacket 4 is further formed by winding a tape 5'.

Note that the water-absorbing powder 7 is a polyethylene oxide coating film 6.
It is not shown separately in the drawing of FIG. 1 because it is thinly coated on the surface of.

FIG. 2 shows the construction of an embodiment of the waterproof optical fiber cable manufacturing apparatus of the present invention for manufacturing the waterproof optical fiber cable shown in FIG.

In FIG. 2, 8.8' and 8'' represent the wound optical fiber 1.1' and the slot-shaped spacer 2;
Each is a drum-shaped protruding portion. 9.
9' and 9'' are cases filled with polyethylene oxide solution, and optical fiber core wires 1.1' and 1.1', which are drawn out from the extending parts 8.8' and 8'', respectively, are used as polyethylene oxide solution application parts. A polyethylene oxide solution P is applied to the surface of the slot-shaped spacer 2 to form a polyethylene oxide coating film 6. 1O is a water-absorbing powder adhesion part provided at the rear of the cases 9.9' and 9'', and the optical fiber core 1.1' on which the polyethylene oxide coating film 6 is formed and the slot-shaped spacer 2 are coated with, for example, acrylic acid-based powder. A water-absorbing powder 10' such as powder is sprinkled from above to adhere to the surface of the polyethylene oxide coating film 6.

Furthermore, 11 is a drying chamber for removing the solvent in the polyethylene oxide solution remaining on the surface of the polyethylene oxide coating film 6; 12 is a cable jacket manufacturing unit for forming the cable jacket 4 on the outside of the core pressing tape 5'; ,1
Reference numeral 3 denotes a cable winding drum which is arranged after the cable sheath manufacturing section 12 and winds up the finished waterproof optical fiber cable.

In the above configuration, the protruding portion 8.8'.

8'', 8''' and the cable winding drum 13 are started, and the cable components such as the slot spacer 2 and the optical fiber core 1゜1' are pulled out from the extending portions 8゜8', 8'', and the parts are removed. All or one part of Case 9
．． 9', 9'' through the polyethylene oxide solution, and almost immediately after that, a water absorbent powder 10' such as acrylic acid powder is applied at a water absorbent powder attachment part 10,
The optical fibers 1.1' are helically wound and assembled in the cavity (helical groove) of the slot-shaped spacer 2, and then passed through the drying chamber 11 to a solvent (e.g., toluene, xylene, etc.) in the polyethylene oxide solution. ) part is separated and vaporized. The above-mentioned water-absorbing powder is attached to the optical fiber core 1.
．． Although it is performed before the winding of 1', the powder deposition may be continued after the winding.

As a result, an optical fiber cable core in which the water-absorbing powder 7 is adhered to the polyethylene oxide coating film 6 is obtained, and a water-absorbing core-pressing tape is further protruded from the protruding portion 8'' on the outer periphery of the cable core. 5′
After that, the cable core is passed through the cable sheath manufacturing section 12 to cover the core with the sheath 4, and then wound onto the cable winding driver 13.

At this time, by rotating the protruding portion 8' in the direction of arrow R in FIG. 2, the optical fiber core 1.1' can be wound in the gap of the slot-shaped spacer 2. Furthermore, water-absorbing short fibers such as acrylic short fibers may be used instead of the water-absorbing powder 10'.

Through such a manufacturing process, a waterproof optical fiber cable as shown in FIG. 1 can be manufactured. This waterproof optical fiber cable absorbs seawater through the polyethylene oxide coating film 6, and absorbs ordinary water through the water-absorbing powder 7. Further, the polyethylene oxide liquid is also solidified in the drying chamber 11, and at the same time, the water-absorbing powder 7 is also fixed and does not move.

Table 1 below shows that the slot-shaped spacer 2 and the optical fiber core 1 are each coated with polyethylene oxide,
The experimental results of the water running length (water running length) are shown for the case where water-absorbing powder was attached and the case where all or part of the processing was not performed. In addition, in this experiment, the polyethylene oxide coating and water-absorbing powder adhesion were 2 to 4 g/m.
Water-absorbing core-pressing tape 5'
A seawater test was conducted using

According to the experimental results shown in Table 1, if polyethylene oxide is applied to the slot-shaped spacer 2 and the optical fiber core 1, and water-absorbing powder is attached to the slot-shaped spacer 2 and the optical fiber core 1, the optical fiber will remain intact even when water including seawater enters. The running length of the cable is completely 1m or less. If polyethylene oxide is applied to either the slot-shaped spacer 2 or the optical fiber core 1 and water-absorbing powder is attached, the water running will be 1.
There are cases where it stops and cases where it does not stop at less than m, and it seems to differ depending on the application and the degree of adhesion.

In this way, the effect of preventing water running can be achieved by applying polyethylene oxide to either the slot spacer or the optical fiber core and attaching water-absorbing powder, but it is even more effective to apply it to either of the two. I know that I can do my best.

[Effects of the Invention] As explained above, according to the present invention, polyethylene oxide is applied to at least one of the slot-shaped spacer and the optical fiber core, and the surface of the applied polyethylene oxide is coated with water-absorbing powder or On the optical fiber cable core formed by attaching water-absorbing short fibers,
Since the cable is constructed by wrapping a water-absorbent core-pressing tape and covering it with the cable jacket, the thin polyethylene oxide film and water-absorbing powder inside the cable absorb seawater and ordinary water well. In addition, since the water-absorbing powder is fixed, there is no chance of the powder falling off, and since the polyethylene oxide itself is used instead of adhesive, it is easy to manufacture, making it easy to create waterproof optical fiber cables with excellent waterproof properties against seawater, etc. can get.

Note that the present invention can also be effectively applied to waterproof metal cables.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of an embodiment of the waterproof optical fiber cable of the present invention, and FIG. 2 is a configuration showing an example of the configuration of an embodiment of the manufacturing apparatus of the present invention for manufacturing the waterproof optical fiber cable shown in FIG. 1. FIG. 3 is a sectional view showing an example of the configuration of a conventional optical fiber cable. 1.1'... Optical fiber core wire, 2... Slot type spacer, 3... Tension member, 4... Outer cover, 5... Non-water-absorbent core holding tape, 5'.・・Water-absorbent core pressing tape, 6 ・Polyethylene oxide coating film, 7 ・Water-absorbent powder, 8.8', 8'', 8'''... Extruded part, 9.9'
, 9"...Case (polyethylene oxide solution application part), lO...Water-absorbing powder adhesion part, 10'...Water-absorbing powder, 11...Drying room, 12...Cable jacket manufacturing part , 13... Cable winding drum. Fig. 1

Claims (1)

[Scope of Claims] 1) Polyethylene oxide is applied to at least one of the optical fiber core and a slot-shaped spacer having a groove for accommodating the optical fiber core, and the surface of the applied polyethylene oxide absorbs water. an optical fiber cable core formed by adhering water-absorbent short fibers or water-absorbing short fibers; a water-absorbent core-wrapping tape wound on the outside of the optical fiber cable core; and a cable coated on the outside of the core-squeeze tape. A waterproof optical fiber cable characterized by comprising an outer jacket. 2) A protruding portion for respectively protruding an optical fiber coated wire and a slot-shaped spacer having a groove portion for storing the optical fiber coated wire, and a portion of the optical fiber coated wire and the slot-shaped spacer protruded by the protruding portion. a coating section that applies a polyethylene oxide solution to either one of the coating sections; and a winding section that is arranged after the coating section and that wraps the optical fiber in the groove of the slot-shaped spacer to form an optical fiber cable core. , an adhesion section that is disposed after the application section and that attaches water-absorbing powder or water-absorbent short fibers to the surface of the applied polyethylene oxide; and a drying section that removes the solvent in the polyethylene oxide solution remaining on the surface. , a tape winding section that is arranged after the drying section and wraps a water-absorbent core-squeezing tape around the outer periphery of the optical fiber cable core after drying in the drying section; 1. A waterproof optical fiber cable manufacturing apparatus, comprising: a jacket manufacturing section that forms a jacket.