JP2008090213A - Tension member for communication cable, and communication cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tension member for communication cable having its intrinsic function and also a function for preventing coated optical fibers from being damaged caused by the oviposition of cicadas, and to provide a communication cable capable of being processed more inexpensively than a conventional communication cable and advantageous in functionality, processability and workability. <P>SOLUTION: The tension member 3 is placed in juxtaposition in the periphery of a coated optical fiber 2 installed in a communication cable 1, is used for the purpose of protecting the coated optical fiber 2, and is composed of a synthetic resin monofilament. The tension member for communication cable is characterized in that the synthetic resin monofilament is formed in a deformed cross section with more than one recessed part 6 for surrounding and protecting at least a part of the coated optical fiber 2, and that the Young's modulus is ≥12,000 N/mm<SP>2</SP>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a strength member for a communication cable and a communication cable in which the strength member is disposed in a part of the communication cable.

  In recent years, communication cables using optical fibers (optical fibers) have been mainly used for cables used for FTTH (fiber to the home) because a large amount of information can be transmitted and received instantaneously. Yes.

  Here, generally, as shown in FIG. 3, a communication cable has an optical core 2 serving as an information transmission medium at the center thereof and a cable member called a tensile body 3 (or a reinforcing wire) for drawing into the house from a utility pole. In addition, the optical fiber 2 and the tension member 3 are covered with a member called a sheath 4.

  The sheath 4 is formed with a tearing groove called a notch 5 for tearing the sheath 4 when the communication cable is connected to a receiving device or the like to expose the optical core 2, and the notch 5 is formed in the sheath 4. Since the sheath 4 is torn, the optical core 2 can be easily exposed.

  However, while communication cables using optical fibers have been extended, in recent years, there has been an increase in the damage caused by insect pests such as bear swallows laying egg-laying tubes in communication cables and laying eggs inside them. In addition to damaging the optical fiber due to the spawning tube damaging the optical fiber, rainwater is immersed inside the communication cable through the wound hole opened by the laying tube, and the optical transmission characteristics of the optical fiber are reduced. Problems such as a significant drop have occurred.

  In particular, since the thickness of the sheath between the optical core and the notch is thinner than in other places, the egg-laying tube easily reaches the optical core and is easily damaged when the egg is laid from the notch.

  As a countermeasure for this problem, a method has been tried to harden the sheath material and make it less likely that the bearfish and the like will pierce the laying tube. In this case, however, the sheath will be difficult to tear when connecting the communication cable. It became clear that problems occurred and lacked practicality.

  In addition, methods such as thickening the sheath so that the oviposition tube of the bear oak does not reach the optical core have also been tried, but the thickening of the sheath makes the communication cable thicker and less flexible. When installing, there were problems such as difficult handling.

  Furthermore, in order to reduce the damage caused by the oviposition of the oviduct from the notch, attempts were made to either not provide a notch or to shift the notch from the parallel line of the optical fiber, but no effect was observed. It was.

  In response to these attempts, fiber optic drop cables (for example, patents) that add a spicy component to the sheath material, or have an insecticidal / insecticidal component applied to the surface of the cable so that the cable does not bite against birds, beasts and animals Reference 1) has already been known, but actually, it was hardly effective in preventing spawning of burdock etc.

  Also, a self-supporting optical cable for pulling in which a notch is provided in an optical element part in which an optical core and a pair of tensile strength members arranged parallel to the left and right sides are covered with a sheath, and a metal wire braid and an outer sheath are provided on the surface. (See, for example, Patent Document 2).

  This optical cable is covered with a metal wire knitted fabric around the optical element part, so it is difficult to pierce the laying tube of the bear swallow and can reduce damage to the optical core line. Since the outer metal sheath is removed from the outer sheath and the metal wire braid, the optical core must be exposed by tearing the sheath of the optical element section. Workability was extremely poor.

Furthermore, since this optical cable requires a metal wire knitted sheath and outer sheath covering, it is difficult to manufacture easily as in the conventional case, and there are problems in terms of workability such as an increase in manufacturing cost. In addition, since metal wire knitting is used, there was a problem that it was easily damaged by lightning surge current caused by lightning strikes.
JP 2005-37526 A JP 2006-126687 A

  The object of the present invention is to combine a function as an original tensile body and a function to prevent damage to the optical core due to damage caused by spawning of bearfish. It is possible to manufacture communication cables with a small number of members without the need to install new members, so that it can be processed at a lower cost than conventional communication cables, and when connecting communication cables to receiving devices, etc. An object of the present invention is to provide a communication cable strength member capable of easily tearing a sheath and exposing an optical fiber as in the case of a conventional communication cable, and a communication cable using the strength member.

In order to achieve the above object, according to the present invention, there is provided a tensile body comprising a synthetic resin monofilament that is provided in the vicinity of an optical fiber installed in a communication cable and used for protecting the optical fiber. The synthetic resin monofilament is formed in a modified cross-sectional shape having one or more concave portions for enclosing and protecting at least a part of the optical fiber, and according to JIS L1013-1999, 8.10 A tensile strength body for a communication cable is provided, wherein the measured Young's modulus is 12000 N / mm ² or more.

In the present invention,
The irregular cross-sectional shape of the synthetic resin monofilament is any shape selected from V-type, U-type, H-type, Y-type, T-type, X-type and L-type;
The synthetic resin monofilament is made of at least one selected from a polyamide-based resin, a polyester-based resin, a fluorine-based resin, and polyphenylene sulfide;
The synthetic resin monofilament is composed of a polyester-based resin containing 85 mol% or more of ethylene-2,6-naphthalate units, and in accordance with B method of 8.18.2 of JIS L1013-1999 of the synthetic resin monofilament. The measured dry heat shrinkage at 140 ° C. is 5.0% or less as a preferable condition. By further satisfying these conditions, a more excellent effect can be obtained.

  Further, the communication cable of the present invention uses a plurality of strength members for the communication cable, and the strength members are provided around the optical fiber so as to surround at least a part of the optical fiber with its concave portion. In addition, a sheath is formed around the optical fiber and the tensile strength member for the communication cable.

  According to the present invention, as described below, particularly when used in a communication cable using an optical fiber, it has both a function as an original tensile body and a function to prevent damage to the optical core due to spawning damage of the bearfish. Unlike conventional communication cables, there is no need to install new members to prevent spawning damage in bear jellies, and the communication cable can be processed with fewer members, so it is less expensive than conventional communication cables. A manufacturable strength member for a communication cable can be obtained.

  In addition, when connecting to a receiving device or the like, it is possible to easily tear the sheath and expose the optical core wire like a conventional communication cable, so in all aspects of functionality, workability and workability, It is possible to obtain a communication cable that exhibits new performance that cannot be obtained with a conventional communication cable.

  Hereinafter, the tensile strength body for a communication cable of the present invention and the communication cable using the same will be described in detail.

  FIG. 1 is a cross-sectional view showing an example of a communication cable strength member and a communication cable according to the present invention. 1 is a communication cable, 2 is an optical fiber, 3 is a communication cable strength member (hereinafter simply referred to as a tensile strength). 4 is a sheath, and 5 is a notch.

  2 (a) to (i) are cross-sectional views of the communication cable when a tensile body having a cross-sectional shape different from that of FIG. 1 is used, and FIGS. 2 (g) to (i) are cross-sectional views of the tensile body. FIG. 2 is a cross-sectional view of a communication cable when arranged differently from FIG. 1.

  As is apparent from FIG. 1, the communication cable 1 of the present invention is made of a synthetic resin monofilament having a deformed cross-sectional shape in which the strength member 3 has one or more concave portions 6 unlike the conventional communication cable shown in FIG. The tensile body 3 is surrounded by at least a part of the optical core 2 (all of the optical core 2 in the case of FIG. 1) with the concave portions 6 of the plurality of tensile bodies 3 (two in FIG. 1). In addition, a sheath 5 is formed around the converging body 7 of the optical fiber 2 and the tensile body 3.

  A particularly important point in the present invention is the cross-sectional shape and function of the synthetic resin monofilament that forms the strength member 3, and the optical core 2 is formed by the concave portion 6 of the strength member 3 while having the original strength member function. It has a function not present in conventional tensile bodies that prevents the damage to the optical core 2 by preventing the egg-laying tube of the bearfish from reaching the optical core 2.

  Therefore, since the strength member 3 of the present invention has the two functions described above, a new member such as another strength member or a reinforcing wire is used to prevent the spawning damage of the black swallow, like the conventional communication cable. Is not required to be installed in the communication cable, and the communication cable can be manufactured with a small number of members. Therefore, there is an advantage in terms of workability such that it can be processed at low cost.

  Further, as can be seen from FIG. 1, the strength members 3 used in a plurality are arranged so as to be separated from each other while surrounding the optical fiber 2, so that the communication cable 1 is connected to a receiving device or the like. In doing so, the tensile body 3 can be easily peeled off together with the sheath 4 to expose the optical fiber 2.

  Therefore, it can be said that the strength member 3 of the present invention has extremely advantageous characteristics in terms of workability when the communication cable 1 is connected.

  Thus, the strength member 3 of the present invention can exhibit new performance that cannot be obtained with conventional communication cables in all aspects of functionality, workability, and workability.

  Here, the material resin of the synthetic resin monofilament constituting the strength member 3 of the present invention is not particularly limited as long as it has a function as the original strength member 3 and is difficult to penetrate the oviposition tube of the koma-zemi. However, it is preferable to use at least one selected from known synthetic resins such as polyamide-based resins, polyester-based resins, fluorine-based resins, and polyphenylene sulfide.

  For example, in the case of a polyamide-based resin, 6 nylon, 66 nylon, 610 nylon, 612 nylon, nylon 6/66 copolymer, nylon 6/12 copolymer, or a copolymer or blend of two or more of these may be mentioned. Among them, nylon 610 is preferable.

  In the case of a polyester-based resin, there may be mentioned polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene terephthalate, polymethylene naphthalate, polybutylene naphthalate, polypropylene naphthalate or a copolymer or blend of two or more of these, Among them, polyethylene naphthalate, polymethylene naphthalate, polybutylene naphthalate, and polypropylene naphthalate are preferable. Particularly, high strength can be easily obtained, and ethylene-2 Polyester resins containing 85 mol% or more of 1,6-naphthalate units are preferred.

  The polyester resin may contain other dicarboxylic acid components and diol components as long as the object of the present invention is not impaired. Examples of the dicarboxylic acid components include terephthalic acid, isophthalic acid, Phthalic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, benzophenone dicarboxylic acid, phenylindane dicarboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, cyclohexane dicarboxylic acid, and decalin dicarboxylic acid are used as diol components. Are ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentylene glycol , Aliphatic glycols such as cyclohexanediol and cyclohexanedimethanol, o-xylylene glycol, p-xylylene glycol, m-xylylene glycol, 1,4-bis (2-hydroxyethoxy) benzene, 1,4- Bis (2-hydroxyethoxyethoxy) benzene, 4,4′-bis (2-hydroxyethoxy) biphenyl, 4,4′-bis (2-hydroxyethoxyethoxy) biphenyl, 2,2-bis [4- (2- Hydroxyethoxy) phenyl] propane, 2,2-bis [4- (2-hydroxyethoxyethoxy) phenyl] propane, 1,3-bis (2-hydroxyethoxy) benzene, 1,3-bis (2-hydroxyethoxyethoxy) ) Benzene, 1,2-bis (2-hydroxyethoxy) benzene, 1 Aromatic glycols such as 2-bis (2-hydroxyethoxyethoxy) benzene, 4,4′-bis (2-hydroxyethoxy) diphenylsulfone, 4,4′-bis (2-hydroxyethoxyethoxy) diphenylsulfone, and hydroquinone 2,2-bis (4-hydroxyphenyl) propane, resorcin, catechol, dihydroxynaphthalene, dihydroxybiphenyl, dihydroxydiphenylsulfone, and other diphenols can be appropriately selected and used.

  In the case of fluororesin, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, polyvinylidene fluoride and tetrafluoroethylene / Hexafluoropropylene / vinylidene fluoride copolymer and the like can be mentioned, among which ethylene / tetrafluoroethylene copolymer is preferable.

  Furthermore, in the synthetic resin monofilament forming the tensile strength body 3 of the present invention, titanium oxide, silicon oxide, calcium carbonate, magnesium carbonate, barium carbonate, barium sulfate, calcium sulfate, Inorganic particles such as barium phosphate, lithium phosphate, calcium phosphate, magnesium phosphate, aluminum oxide, zirconia, lithium fluoride, kaolin, talc, heat-resistant agent, weather-resistant agent, light-resistant agent, hydrolysis-resistant agent, UV-resistant agent, antioxidant Additives such as agents, antistatic agents, smoothing agents, waxes, silicone oils, surfactants, dyes and pigments can be optionally added as necessary.

Next, the tensile strength body 3 of the present invention needs to have a Young's modulus measured in accordance with JIS L1013-1999 of 8.10 of 12000 N / mm ² or more, and further 18000 N / mm ² or more. Is more preferable.

  The reason is that if the Young's modulus of the strength member 3 is below the above range, a strength member lacking in strength is easily obtained. If this strength member is installed in a communication cable, problems such as disconnection in the communication cable. It is because it becomes easy to be invited.

Note that the higher the Young's modulus of the tensile body 3 is particularly preferable because it exhibits excellent strength when installed in a communication cable. However, problems in manufacturing the tensile body 3 and the material of the tensile body 3 itself are preferable. The upper limit is preferably about 30000 N / mm ² .

  The cross-sectional shape of the synthetic resin monofilament forming the strength member 3 of the present invention is the same as the shape shown in FIG. 1, with the concave portion 6 formed to surround and protect at least a part of the optical fiber 2. As long as there are two or more, the shape may be any shape, but flexibility when installed in the communication cable 1, processability of the spinneret in the melt spinning of the synthetic resin monofilament that will be the tensile body 3 described later In consideration of the discharge stability of the synthetic resin from the spinneret, V type (a), U type (b), H type (c), Y type as shown in FIGS. More preferably, the shape is any one of (d), T-type (e), X-type (f), and L-type (g), or a shape (h, i) similar thereto.

  In particular, the H-type is more preferable because it has excellent adhesion to the sheath 4, and even if it has a shape other than the H-type, the adhesion can be improved by appropriately providing an uneven shape different from the recessed portion 6. Can do.

  The size of the concave portion 6 in the synthetic resin monofilament forming the strength member 3 of the present invention can be appropriately selected according to the thickness of the optical core 2 to be used, and is not particularly defined. When a 25 mm optical core 2 is used, it is preferable to set the width of the opening of the concave portion 6 to about 0.3 to 0.6 mm and the depth to about 0.3 to 0.5 mm.

  The size of the synthetic resin monofilament forming the tensile strength 3 can be appropriately selected according to the number of the tensile strength members 3 used and the thickness of the communication cable 1 and is not particularly specified. In order to give flexibility, it is preferable that the diameter of the circle circumscribing the cross-sectional shape of the strength member 3 is about 0.5 to 3.0 mm.

  Furthermore, the synthetic resin monofilament forming the strength member 3 of the present invention has a dry heat shrinkage rate at 140 ° C. of 5.0% or less measured according to B method of 8.18.2 of JIS L1013-1999. Is more preferable, and more preferably in the range of 1.0% or less.

  The reason for this is that when the dry heat shrinkage rate exceeds the above range, the tensile body 3 tends to heat shrink. Therefore, when the communication cable is processed by melting the sheath 4 around the optical core 2 and the tensile body 3, This is because the tensile body 3 contracts and becomes easier to meander in the communication cable 1 and the communication cable 1 lacking in quality tends to be easily obtained.

  The synthetic resin monofilament forming the strength member 3 of the present invention can be produced, for example, using the following method.

  First, a synthetic resin as a raw material is supplied to a known melt spinning machine, for example, an extruder type melt spinning machine, and melt-kneaded in the melt spinning machine.

  The melt-kneaded synthetic resin is extruded from the spinneret hole corresponding to the desired cross-sectional shape, and is subsequently guided into the cooling bath to be cooled and solidified.

  In the cooling and solidification process, if the liquid surface of the cooling bath is shaken by blowing gas on the liquid surface, discharging the liquid, or generating a waveform with a pump or the like, the surface of the undrawn yarn As a result, a synthetic resin monofilament with small linear spots is obtained.

  Next, the obtained undrawn yarn is heat-drawn under the condition of magnification necessary for obtaining a target Young's modulus. The magnification condition for obtaining the target Young's modulus varies depending on the type of synthetic resin to be used. For example, when a polyester resin is used, 2.5 to 8.5 times, particularly ethylene-2,6-naphthalate unit. When using a polyester-based resin containing 85 mol% or more, 6.0 to 7.8 times, when using a polyamide-based resin, 2.5 to 5.0 times, and when using a fluorine-based resin, 4. When using PPS at 0 to 5.0 times, it is necessary to heat and stretch at 3.0 to 6.0 times. In addition, although it changes with kinds of synthetic resin to be used also about the temperature conditions at the time of heat-stretching, it is normally performed at the temperature below the melting point below the glass transition point of a synthetic resin.

  Thereafter, the heat-stretched synthetic resin monofilament is subjected to a heat-relaxation treatment as necessary and is wound up once.

  Next, the communication cable 1 is processed using the obtained synthetic resin monofilament. The communication cable 1 does not need to be manufactured by any special method and can be processed by a known apparatus and method. However, when processing the communication cable 1 of the present invention, a plurality of strength members 3 are used, It is important to place the optical fiber 2 around the optical fiber 2 so as to surround at least a part of the optical fiber 2 with the concave portion 6 of the strength member 3.

  Therefore, if the optical fiber 2 is not surrounded by the concave portion 6 of the strength member 3, the egg-laying damage is likely to occur due to the bearfish.

  The arrangement of the tensile body 3 in the communication cable may be any arrangement as long as the tensile body 3 is provided side by side with the concave portion 6 so as to surround the optical fiber 2, as shown in FIGS. 1 and 2. Not only the arrangements (a) to (g) but also a method in which three or more strength members 3 are provided around the optical fiber 2 as shown in FIG. Considering the space that can be provided in the communication cable 1 and the thickness that can provide sufficient strength as the strength member 3, the number of strength members 3 that are provided in the communication cable 1 is preferably 2 to 4.

  Moreover, according to the characteristic requested | required of the communication cable 1, as shown to (i) of FIG. 2, you may use the tension body 3 of a different cross-sectional shape suitably combining.

  The communication cable 1 of the present invention thus obtained has the conventional strength of the tensile strength body 3 of the present invention as well as the function of preventing the damage of the optical core due to the spawning damage of the bearfish. Unlike the cable, there is no need to install a new member in the communication cable to prevent the spawning damage of the bearfish, and the communication cable 1 can be processed at a low cost.

  Further, when the communication cable 1 is connected to a receiving device or the like, the optical fiber 2 can be easily exposed by simply tearing the sheath 4 in the same manner as a conventional communication cable.

  Thus, the communication cable 1 using the strength member 3 of the present invention exhibits new performance that cannot be obtained with conventional communication cables in all aspects of functionality, workability, and workability. be able to.

  Hereinafter, the tensile strength body and the communication cable of the present invention will be described in more detail based on examples. The strength member and the communication cable of the present invention are not limited to the examples.

  Moreover, each physical property of a tensile strength body and the performance evaluation of a communication cable were performed by the following method.

[Young's modulus]
According to JIS L1013-1999, 8.10, “Tensilon” UTM-4-100 type tensile tester manufactured by Orientec Co., Ltd. was used to obtain a load-elongation curve of a synthetic resin monofilament. Thereafter, the Young's modulus (N / mm ² ) was determined from the obtained load-elongation curve. The tensile speed was 300 mm / min, and the average value was evaluated 10 times.

[Dry heat shrinkage at 140 ° C.]
According to JIS L1013-1999 8.18.2, a synthetic resin monofilament was cut to 500 mm and left in a gear oven at 140 ° C. for 30 minutes. Thereafter, the length of the synthetic resin monofilament was measured again, and the shrinkage (%) was calculated. In addition, the measurement was performed 5 times and the average value was evaluated.

[Performance evaluation of communication cable]
The two strength members obtained in the examples were arranged as shown in FIG. 1 to prepare a communication cable, and used for the following performance evaluation. The optical fiber was 0.3 mm in diameter, the sheath was polyethylene resin (Unitika, 9739), and the cross-sectional size of the communication cable was 3.0 mm long × 2.0 mm wide.

A. Oviposition damage (functional evaluation)
During the three months from July to September, the communication cable was stretched 10m between the outdoor utility poles, and the damage caused by the black spot was actually investigated and evaluated according to the following criteria.
○: No damage to the optical fiber due to spawning of the bearfish was found, and it was very good.
(Triangle | delta): Although the damage to the optical core wire by egg-laying of a black-burdock was seen 1-2 place, there was no problem practically.
×: Damage to the optical core due to spawning of the bearfish was observed everywhere, and it was in a state where it could not be used.

B. Function as a tensile body (functional evaluation)
Whether the obtained tensile body fulfills its function was evaluated according to the following criteria.
○: There was no breakage when the communication cable was stretched, and no meandering occurred during processing.
Δ: During processing, some meandering occurred, but it was not a problem.
X: It did not function sufficiently as a tensile strength body, such as breaking when the communication cable was stretched or meandering during processing.

C. Ease of handling (workability evaluation)
Tension / connection work was actually performed, and the ease of handling of communication cables was evaluated according to the following criteria.
○: It was very easy to handle, such as having the same flexibility as a conventional communication cable and easily exposing the optical fiber.
Δ: It is slightly less flexible than the conventional communication cable, and it is difficult to easily expose the optical core, but there was no particular problem in handling.
X: It was difficult to handle than conventional communication cables, such as poor flexibility and difficulty in exposing the optical core.

D. Communication cable processability and cost (processability)
The workability and cost of the communication cable were evaluated according to the following criteria in comparison with the conventional communication cable shown in FIG.
○: Easier to process than conventional, low cost.
X: Workability equivalent to or lower than conventional, or cost equivalent to or higher.

[Example 1]
A copolyester resin containing 92 mol% of ethylene-2,6-naphthalate units (PN640 manufactured by Toyobo Co., Ltd., hereinafter referred to as PEN) is supplied to an extruder type melt spinning machine, and the melted and kneaded copolymer in the melt spinning machine. A melt of the polymerized polyester resin was extruded from a spinneret corresponding to an H-shaped cross-sectional shape, and immediately introduced into a cooling bath to be cooled and solidified.

  Thereafter, the cooled and solidified unstretched yarn is heated and stretched 7.5 times in a dry hot air bath at a temperature of 200 ° C. and in a dry hot air bath at a temperature of 240 ° C., and then in a dry hot hot air bath at a temperature of 260 ° C. Was subjected to relaxation heat treatment to obtain a synthetic resin monofilament having a circumscribed circle diameter of 1.0 mm and an H-shaped cross section.

  Thereafter, the obtained synthetic resin monofilament was used as a tensile body, and a communication cable as shown in FIG.

  Table 1 summarizes various physical properties of the tensile body and performance evaluation of the communication cable.

[Examples 2 to 7]
V-type, U-type, Y-type under the same conditions as in Example 1 except that spinnerets corresponding to V-type, U-type, Y-type, T-type, X-type and L-type cross-sectional shapes were respectively used. Mold, T-type X-type and L-type cross-section synthetic resin monofilaments were obtained.

  Then, each synthetic resin monofilament obtained was used as a tensile body, and communication cables as shown in (a) to (b) and (d) to (g) of FIG. 2 were prepared.

  Table 1 summarizes various physical properties of the tensile body and performance evaluation of the communication cable.

[Example 8]
A polyethylene terephthalate resin (T701T manufactured by Toray Industries, Inc., hereinafter referred to as PET) is supplied to an extruder type melt spinning machine, and the melt of the copolymerized polyester resin melt-kneaded in the melt spinning machine corresponds to an H-shaped cross-sectional shape. The product was extruded from the spinneret and immediately led into a cooling bath to be cooled and solidified.

  Thereafter, the cooled and solidified undrawn yarn is heated and drawn 5.5 times in a hot water bath at a temperature of 93 ° C. and in a dry hot air bath at a temperature of 180 ° C., and then relaxed in a dry hot air bath at a temperature of 260 ° C. By performing heat treatment, a synthetic resin monofilament having an H-shaped cross-section with a circumscribed circle diameter of 1.0 mm was obtained.

  Thereafter, the obtained synthetic resin monofilament was used as a tensile body, and a communication cable as shown in FIG.

  Table 1 summarizes various physical properties of the tensile body and performance evaluation of the communication cable.

[Example 9]
610 nylon resin (M2001C manufactured by Toray Industries, Inc., hereinafter referred to as N610) is supplied to an extruder type melt spinning machine, and the melt of the copolymerized polyester resin melt-kneaded in the melt spinning machine corresponds to an H-shaped cross-sectional shape. The product was extruded from the spinneret and immediately led into a cooling bath to be cooled and solidified.

  Thereafter, the cooled and solidified undrawn yarn was heated and drawn 4.8 times in a hot water bath at a temperature of 80 ° C. and in a dry hot air bath at a temperature of 120 ° C., and then relaxed in a dry hot air bath at a temperature of 200 ° C. By performing heat treatment, a synthetic resin monofilament having an H-shaped cross-section with a circumscribed circle diameter of 1.0 mm was obtained.

  Thereafter, the obtained synthetic resin monofilament was used as a tensile body, and a communication cable as shown in FIG.

  Table 1 summarizes various physical properties of the tensile body and performance evaluation of the communication cable.

[Example 10]
An ethylene / tetrafluoroethylene copolymer resin (Fluoron ETFE C-88AXMP manufactured by Asahi Glass Co., Ltd., hereinafter referred to as ETFE) is supplied to an extruder type melt spinning machine, and the copolymer polyester resin melted and kneaded in the melt spinning machine is melted. The product was extruded from a spinneret corresponding to an H-shaped cross-sectional shape, immediately introduced into a cooling bath, and cooled and solidified.

  Thereafter, the cooled and solidified unstretched yarn was heated and drawn 4.8 times in a hot water bath at a temperature of 90 ° C. and in a dry hot air bath at a temperature of 180 ° C., and then relaxed in a dry hot air bath at a temperature of 230 ° C. By performing heat treatment, a synthetic resin monofilament having an H-shaped cross-section with a circumscribed circle diameter of 1.0 mm was obtained.

  Thereafter, the obtained synthetic resin monofilament was used as a tensile body, and a communication cable as shown in FIG.

  Table 1 summarizes various physical properties of the tensile body and performance evaluation of the communication cable.

[Example 11]
A polyphenylene sulfide resin (E2080 manufactured by Toray Industries, Inc., hereinafter referred to as PPS) is supplied to an extruder type melt spinning machine, and the melt of the copolymerized polyester resin melt-kneaded in the melt spinning machine corresponds to an H-shaped cross-sectional shape. The product was extruded from the spinneret and immediately led into a cooling bath to be cooled and solidified.

  Thereafter, the cooled and solidified undrawn yarn is heated and drawn 5.0 times in a wet hot bath at a temperature of 101 ° C. and in a dry hot hot air bath at a temperature of 170 ° C., and then relaxed in a dry hot hot air bath at a temperature of 200 ° C. By performing heat treatment, a synthetic resin monofilament having an H-shaped cross-section with a circumscribed circle diameter of 1.0 mm was obtained.

  Thereafter, the obtained synthetic resin monofilament was used as a tensile body, and a communication cable as shown in FIG.

  Table 1 summarizes various physical properties of the tensile body and performance evaluation of the communication cable.

[Comparative Example 1]
A circular cross-section synthetic resin monofilament having a diameter of 0.8 mm was obtained under the same conditions as in Example 1 except that melt spinning was performed using a spinneret corresponding to a circular cross-section.

  Thereafter, the obtained synthetic resin monofilament was used as a tensile body to prepare a communication cable as shown in FIG.

  Table 1 summarizes various physical properties of the tensile body and performance evaluation of the communication cable.

[Comparative Example 2]
An elliptical cross-section synthetic resin monofilament having a major axis of 1.0 mm and a minor axis of 0.5 mm was obtained under the same conditions as in Example 1 except that melt spinning was performed using a spinneret corresponding to an elliptical section.

  After that, use the obtained synthetic resin monofilament as a tensile body, so that the optical fiber is sandwiched between the optical fiber and the notch so that the kuma-zemi will not puncture the optical fiber by piercing the oviduct from the notch. A communication cable was created by installing a tensile body inside.

  Table 1 summarizes various physical properties of the tensile body and performance evaluation of the communication cable.

[Comparative Example 3]
An H-shaped cross-section synthetic resin monofilament was obtained under the same conditions as in Example 1 except that the draw ratio was lowered and changed from 7.5 times to 5.0 times.

  Thereafter, the obtained synthetic resin monofilament was used as a tensile body, and a communication cable as shown in FIG.

  Table 1 summarizes various physical properties of the tensile body and performance evaluation of the communication cable.

  As is apparent from the results in Table 1, the tensile body satisfying the conditions of the present invention and the communication cables (Examples 1 to 11) using the same are the functions of the original tensile body and the optical center due to the spawning damage of the bearfish. Combined with the function to prevent damage to the wire, there is no need to install a new member for preventing spawning damage of bearfish, unlike conventional communication cables, and the communication cable can be processed with fewer members Therefore, it can be manufactured at a lower cost than conventional communication cables.

  Further, when connecting a communication cable to a receiving device or the like, it is possible to easily tear the sheath and expose the optical core wire in the same manner as a conventional communication cable. It turns out that it has the performance which was excellent in all the surfaces of functionality, workability, and workability compared with the communication cable (Comparative Examples 1-3) using this.

  As described above, the tensile body of the present invention has the function of preventing optical fiber damage due to spawning damage of bearfish, and the ability to process communication cables at low cost, while having the same function as conventional tensile bodies. Since it is a new product with excellent processability, it will not only be used for optical fiber communication cables, which are expected to increase further, but when used in various other types of cable, it will fully function. Can do.

Sectional drawing which shows an example of the tensile strength body of this invention, and a communication cable. (A)-(g) is sectional drawing which shows the communication cable at the time of using the tension body of a cross-sectional shape different from FIG. 1, (h)-(i) arrange | positioned the tension body differently from FIG. Sectional drawing which shows the communication cable in case. Sectional drawing which shows the conventional communication cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication cable 2 Optical fiber 3 Strength body 4 Sheath 5 Notch 6 Concave part

Claims (6)

It is a tensile strength member made of a synthetic resin monofilament that is provided around the optical fiber installed in the communication cable and used to protect the optical fiber, and the synthetic resin monofilament is at least of the optical fiber. It is formed in an irregular cross-sectional shape having one or more concave parts for enclosing and protecting a part, and the Young's modulus measured according to JIS L1013-1999 8.10 is 12000 N / mm ² or more Tensile body for communication cables. The deformed cross-sectional shape of the synthetic resin monofilament is any shape selected from V-type, U-type, H-type, Y-type, T-type, X-type and L-type. Tensile body for communication cables. The tensile strength body for a communication cable according to claim 1 or 2, wherein the synthetic resin monofilament is made of at least one selected from a polyamide-based resin, a polyester-based resin, a fluorine-based resin, and polyphenylene sulfide. The tensile strength body for a communication cable according to claim 3, wherein the synthetic resin monofilament is made of a polyester resin containing 85 mol% or more of ethylene-2,6-naphthalate units. 5. The dry heat shrinkage rate at 140 ° C. of the synthetic resin monofilament measured at 140 ° C. according to JIS L1013-1999, 8.18.2 method B, is 5.0% or less. The tensile strength body for communication cables according to claim 1. A plurality of strength members for a communication cable according to any one of claims 1 to 5, wherein a plurality of strength members for the communication cable are used to surround at least a part of the optical cord with its concave portion. A communication cable characterized in that a sheath is formed around the optical core wire and the tensile strength member for communication cable along with the surroundings.

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