JP2005172978A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable which does not cause the breaking of a coated optical fiber even when careless bending etc., are applied during the taking-out of the coated optical fiber, is capable of easily applying the conventional coupling method upon the coupling of the optical fiber and, moreover, does not cause the problem of bent habit as is the case in using the conventional optical fiber cord. <P>SOLUTION: The optical fiber cable is provided with a coated optical fiber 26, a tension member 28 which is arranged in parallel to the coated optical fiber 26 and an outer clad 29 which is extruded and coated altogether on the outer periphery of the same. Therein, the outer clad 27 consisting of a polymer material which contains a fatty acid amide base lubricant by 0.5 wt.% to 3 wt.% and has a bending modulus (ASTM D 790) of 80 MPa to 450 MPa is disposed on the coated optical fiber 26. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical fiber cable used for lead-in wiring from a wiring system cable installed in an aerial or underground to a general subscriber's house.

  As a so-called optical drop cable for drawing and wiring from an aerial or underground wiring system cable into a general subscriber's house, steel wire or FRP (glass fiber reinforced plastic) on both sides or one side of a single-core optical fiber There are known tensile strength bodies consisting of the following, which are covered with a resin such as polyethylene (underground optical drop cable), or integrated with a support line along such a cable (aerial optical drop cable) (For example, refer to Patent Document 1).

  FIG. 6 shows an example of an aerial optical drop cable. As shown in the figure, this optical drop cable has single-strand optical fiber core 1 sandwiched between tensile strength members 2 and 2 above and below it, and support wire 3 on top of them, and the outer periphery thereof. It has a structure in which a jacket 4 is provided by batch extrusion coating of a resin such as polyethylene. Between the support wire 3 and the strength member 2 of the cable, a neck portion (connecting portion) 7 for dividing the cable into the support wire portion 5 and the cable portion 6 is provided. The notches 8 and 8 for tearing are provided in the part which the single-core optical fiber core wire 1 is located in both sides.

  In such an optical drop cable, since the support wire 3 is provided, the aerial laying is possible, and the tensile strength member 2 is disposed with the optical fiber core wire 1 interposed therebetween. An increase in fiber transmission loss can be prevented. Further, since the neck portion 7 is provided, the cable portion 8 can be easily separated from the support wire portion 5 and wired indoors after the cable is drawn into the subscriber's house. The support line part 5 is normally fixed to a housing wall surface. Further, since the notch 8 for tearing is provided, it is possible to easily take out the optical fiber core wire 1 by tearing the jacket 4 in the width direction of the cable at the time of cable end processing or the like.

  By the way, in such a conventional optical fiber cable, the outer diameter of the single-core optical fiber core 1 is very thin (usually 250 μm), although it is excellent in the ability to take out the core wire as described above. There is a problem that if the cord 1 is carelessly bent when the core wire 1 is taken out, it is easily broken. For this reason, it is necessary for the worker to take out the core wire with great care, which is a heavy burden.

  Accordingly, in order to cope with this problem, an optical fiber having an outer diameter of about 1 mm to 2 mm in which a tensile fiber layer 9 is provided around the optical fiber core wire 1 and a resin coating layer 10 is provided on the outer side thereof as shown in FIG. The use of the cord 11 in place of the optical fiber core 1 has been studied.

  The optical fiber cord 11 has a high mechanical strength, so that it is not easily broken even if an inadvertent bending is applied when it is taken out from the jacket 4. In addition, when the optical fiber cord 11 thus taken out is connected to an installed wiring system cable or an indoor optical connection device, the optical fiber core wire 1 and the tensile fiber layer 9 and the resin coating layer provided around the optical fiber core wire 1 are provided. 10 is not in close contact with the optical fiber or the optical fiber core wire 1 can be easily exposed (when the optical fiber is exposed, the tensile fiber layer 9 and the resin coating layer 10 are first removed, A coating removal tool such as a hand stripper may be used to remove the coating of the optical fiber core wire 1), a conventional connection method, that is, a method using a connector or fusion, a method called a mechanical connection method, or the like. Can be easily applied.

  The hand stripper is a coating removal tool with two blades on the top and bottom, and the cutting edges of the two blades are provided with semicircular dents, so that only the coating can be bitten without damaging the optical fiber. Can be done. FIG. 8 schematically shows the removal operation of the coating 1a of the optical fiber core 1 using the hand stripper 12, and the two blades of the hand stripper 12 are vertically moved on the coating 1a of the optical fiber core 1. The coating 1a can be cut and removed by biting in both directions and moving the two blades in the length direction of the optical fiber core wire 1 (the direction of the drawing and the arrow) in this state. In FIG. 8, 1b indicates an optical fiber.

Thus, the optical fiber cable using the optical fiber cord 11 has excellent characteristics. However, the optical fiber cord 11 has a drawback that it is easy to bend and bend when it is held in a ring shape for a long time. If it gets bent, it will hinder the manufacture of cables and the reconnection of optical fibers in the closure.
JP 2001-337255 A

  The present invention has been made in response to the above-described problems of the prior art, and the optical fiber core wire is not broken even if an inadvertent bending or the like is applied when the optical fiber core wire is taken out. It is an object of the present invention to provide an optical fiber cable in which a conventional connection method can be easily applied to the connection of the optical fiber cable, and in addition, the problem of bending and bending as in the case of using a conventional optical fiber cord does not occur. To do.

  In order to achieve the above object, an optical fiber cable according to the first aspect of the present invention includes an optical fiber core wire, a tensile body arranged in parallel to the optical fiber core wire, and an outer periphery thereof collectively. An optical fiber cable having an outer sheath coated with extrusion, and having a flexural modulus (ASTM D 790) containing from 0.5% to 3% by weight of a fatty acid amide-based lubricant on the optical fiber core wire, having 80 MPa to 450 MPa A coating made of a polymer material is provided.

  According to a second aspect of the present invention, in the optical fiber cable according to the first aspect, the coating made of the polymer material has a thickness of 50 μm to 400 μm.

  According to a third aspect of the present invention, in the optical fiber cable according to the first or second aspect, the fatty acid amide-based lubricant is at least one selected from the group consisting of erucic acid amide, oleic acid amide, stearyl oleylamide, and bis-oleic acid amide. It is characterized by being a seed.

  According to a fourth aspect of the present invention, in the optical fiber cable according to any one of the first to third aspects, the polymer material is a polyester-based thermoplastic elastomer.

  According to a fifth aspect of the present invention, in the optical fiber cable according to any one of the first to fourth aspects, the polyester-based thermoplastic elastomer is a polyether-polybutylene naphthalate-based thermoplastic elastomer and a polyether-polyethylene. It is at least one kind of a butylene terephthalate thermoplastic elastomer.

  The invention according to claim 6 is the optical fiber cable according to any one of claims 1 to 5, wherein the optical fiber cable is a single-core optical fiber having an outer diameter of approximately 0.25 mm or less. .

  According to the optical fiber cable of the present invention, since the optical fiber core wire is taken out from the jacket while being covered with a coating made of a specific polymer material, it is possible to prevent the optical fiber core wire from being bent when it is taken out. it can. Further, since the coating made of a specific polymer material is provided with an appropriate adhesion on the optical fiber core wire, it can be easily removed using a coating removal tool such as a hand stripper. Therefore, a conventional connection method can be easily applied when connecting optical fibers. In addition, an optical fiber core wire provided with a coating made of a specific polymer material does not bend or become wrinkled even if it is held in an annular state for a long time. It is also possible to prevent a decrease in workability in the reconnection work of the optical fiber.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a first embodiment of the optical fiber cable of the present invention.
As shown in FIG. 1, the optical fiber cable 201 of the present embodiment includes a support line portion 21, a cable portion 22, and a connecting portion 23 that connects these. The support wire portion 21 is composed of a support wire 24 made of a steel wire or the like and an outer sheath 25 provided on the outer periphery thereof. The cable portion 22 has a single-core optical fiber core 26 and a flexural modulus (ASTM D 790) containing 0.5% to 3% by weight of a fatty acid amide-based lubricant provided thereon, and has a flexural modulus (ASTM D 790) of 80 MPa to 450 MPa. A coating 27 made of the above polymer material, and a steel wire, FRP (glass fiber reinforced plastic), and a high tensile strength fiber (Kevlar (trademark)) arranged in parallel at intervals above and below the coated optical fiber core 26. And the like, and a jacket 29 provided on the outer side thereof.

  The outer sheath 25 of the support wire portion 21, the outer sheath 29 of the cable portion 22, and the connecting portion 23 are formed by batch extrusion of a thermoplastic resin such as polyethylene or polyvinyl chloride. In addition, a tear notch 29a is provided at a substantially central portion of both sides of the outer cover 29 of the cable portion 22 and in a portion where the single-core optical fiber core wire 26 is located. By tearing the jacket 29 starting from the tearing notch 29a, the coated single-core optical fiber 26 can be easily taken out.

  The single-core optical fiber core 26 is not particularly limited, and the outer periphery of the optical fiber is coated with a silicone resin or an ultraviolet curable resin, and the outer periphery is further coated with a nylon resin (usually nylon) And so on).

  Examples of the polymer material constituting the coating 27 provided on the single-core optical fiber core 26 include aliphatic polyamide (nylon), polyolefin (for example, polyethylene, ethylene / ethyl acrylate copolymer, ethylene Vinyl acetate copolymers), thermoplastic resins such as polyvinyl chloride, and polyester thermoplastic elastomers such as polybutylene naphthalate thermoplastic elastomers and polybutylene terephthalate thermoplastic elastomers. Polyester thermoplastic elastomers are preferred from the standpoint of ease of molding and bending gusset due to thermal history after laying.

  Examples of the aliphatic amide-based lubricant include erucic acid amide, oleic acid amide, stearyl oleyl amide, and bis-oleic acid amide. Among them, erucic acid amide and oleic acid amide are preferable, and oleic acid amide is particularly preferable. preferable. These lubricants may be used alone or in a combination of two or more.

  If the thickness of the coating 27 is too thin, the effect of protecting the optical fiber core wire 26 will be insufficient. Conversely, if the coating 27 is too thick, the outer diameter of the entire cable portion 22 will increase (the thickness of the jacket 29). If the thickness is reduced, the outer diameter of the entire cable portion 22 can be reduced, but the strength of the jacket 29 is reduced.) From this point of view, the thickness of the coating 27 depends on the type of material constituting the coating 27 and the type of the optical fiber core 26, but is generally provided in the range of 50 μm to 400 μm, and is 75 μm to 375 μm. The range is more preferable, and the range of 125 μm to 330 μm is even more preferable. The coating 27 may be mixed with a colorant in order to identify the single-core optical fiber core wires 26 from each other.

  In the optical fiber cable 201 configured as described above, the flexural modulus (ASTM D 790) containing 0.5% to 3% by weight of a fatty acid amide-based lubricant on the single-core optical fiber 26 is a high value of 80 MPa to 450 MPa. By providing the coating 27 made of a molecular material, the single-core optical fiber core 26 can be taken out from the outer cover 29 together with the coating 27, so that inadvertent bending or the like may occur when the single-core optical fiber core 26 is taken out. Even if it adds, the single fiber optical fiber 26 will not be broken. Thereby, both the operator and the burden are reduced. In addition, when connecting the optical fiber to an installed wiring system cable or an indoor optical connection device after being taken out in this way, only the coating 27 or the coating 27 with a coating stripping tool such as a hand stripper is used. The coating of the optical fiber core wire 26 can be selectively removed as appropriate. For this reason, it is possible to easily apply a conventional connection method, that is, a method using a connector or fusion, a method called a mechanical connection method, or the like. Further, the single-core optical fiber core wire 26 provided with the coating 27 does not bend and become wrinkled even if it is held in a ring-like state for a long period of time as in a conventional optical fiber cord. For this reason, it does not hinder the manufacture of the cable or the reconnection work of the optical fiber in the closure.

  In the present invention, when the bending elastic modulus (ASTM D 790) of the polymer material constituting the coating 27 is less than 80 MPa, the adhesion to the outer cover 29 is increased, and the take-out property of the single-core optical fiber 26 is lowered. Further, when the coating 27 is removed, burrs are generated on the end face. Conversely, when the flexural modulus exceeds 450 MPa, the adhesion between the coating 27 and the single-core optical fiber 26 decreases, and the single-core optical fiber 26 protrudes due to temperature expansion and contraction, resulting in transmission loss. Increase. A preferable range of the flexural modulus (ASTM D 790) is 150 MPa to 400 MPa.

  Further, when the content of the aliphatic amide lubricant is less than 0.5% by weight, the adhesion between the coating 27 and the coating of the single-core optical fiber core 26 becomes excessive, and it is difficult to selectively remove only the coating 27. Therefore, it becomes difficult to apply the mechanical connection method. The mechanical connection method is a method in which the optical fiber cores 26 are abutted and mechanically connected, and is known as an inexpensive and simple connection method compared to fusion or connector connection. On the other hand, when the content of the aliphatic amide lubricant exceeds 3% by weight, the adhesion between the coating 27 and the coating of the single-core optical fiber 26 becomes too small, and the single-core optical fiber from the coating 27 becomes too small. 26 may occur and transmission loss may increase. Further, when the coating 27 is extrusion-coated, slip occurs in the extrusion screw, the resin discharge becomes unstable, and the outer diameter may be changed. A preferred range for the content of the aliphatic amide lubricant is 1.5% by weight to 2% by weight.

  FIG. 2 schematically shows a wiring example of the optical fiber cable 201 of the present embodiment. In FIG. 2, the optical fiber cable 201 connected in the closure 32 to the installed wiring system cable 31 is wired outdoors under the eaves of the subscriber's house 33, where the support line portion 21 is separated and only the cable portion 22 is separated. Is drawn into the subscriber's house 33 and connected to the optical connection device 34 or the like. The support line portion 21 is fixed to the wall surface of the house of the subscriber's house 33. When connecting to the wiring system cable 31, the optical connection device 34, or the like, the optical fiber core wire 26 inside the cable portion 22 is taken out with the coating 27, and the coating 27 or the coating 27 and the coating of the optical fiber core wire 26 are taken out. Are removed as appropriate and connection is made. Since the optical fiber core 26 is taken out with the coating 27, it does not break even if it is inadvertently bent, and the coating can be removed selectively and easily. Therefore, it is possible to easily connect using a conventional connection method.

  Next, another embodiment of the present invention will be described.

  FIG. 3 is a cross-sectional view according to the second embodiment of the present invention, and parts common to FIG.

  The optical fiber cable 202 according to the present embodiment is generally used as a so-called underground drop cable wired underground, and does not have the support line portion 21 and the connecting portion 23, and is the first shown in FIG. The configuration is the same as that of the first embodiment.

  That is, a single-fiber optical fiber 26 and a polymer material having a flexural modulus (ASTM D 790) of 80 MPa to 450 MPa containing 0.5% to 3% by weight of a fatty acid amide lubricant provided thereon. A coating 27, a tensile strength body 28 made of a steel wire, FRP, high-strength fiber, and the like disposed in parallel at a distance above and below the coated optical fiber core 26, and polyethylene provided on the outside thereof And a jacket 29 made of a thermoplastic resin such as polyvinyl chloride. A tear notch 29a is provided at the approximate center of both side portions of the jacket 29, at the portion where the single-core optical fiber core 26 is located.

  Also in the optical fiber cable 202 configured as described above, the single-core optical fiber core 26 can be taken out from the jacket 29 together with the covering 27 as in the case of the first embodiment. Even if an inadvertent bending or the like is added when taking out 26, the single-core optical fiber 26 is not broken, and the burden on the operator is reduced. In addition, when connecting the optical fiber to an installed wiring system cable or an indoor optical connection device after being taken out in this way, only the coating 27 or the coating 27 with a coating stripping tool such as a hand stripper is used. Since the coating of the optical fiber core wire 26 can be selectively removed as appropriate, a conventional connection method, that is, a method using a connector or fusion, a method called a mechanical connection method, etc. can be easily applied for connection. can do. Further, the single-core optical fiber core wire 26 provided with the coating 27 does not become bent even if it is held in a ring for a long period of time as in the case of a conventional optical fiber cord. The optical fiber reconnection work in the closure is not hindered.

  In the present invention, for example, as shown in FIGS. 4 and 5, the number of single-core optical fibers 26 may be two or more. The optical fiber cable 203 shown in FIG. 4 has two single-core optical fibers 26 arranged in the first embodiment and coated with a coating 27, and the optical fiber cable shown in FIG. Reference numeral 204 denotes a structure in which two single-core optical fibers 26 are arranged in each of the second embodiment and a coating 27 is applied to each.

  In the examples described above, the two tension members 28 are arranged in parallel with a space between the upper and lower sides of the single optical fiber core 26, You may make it arrange | position only in any one of upper and lower sides.

  The present invention is particularly effective when the single-core optical fiber core 26 has an outer diameter of approximately 0.25 mm or less.

  Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

Examples 1-6
An optical fiber cable having the structure shown in FIG. 1 was manufactured. The single-core optical fiber core 26 uses a single-core ultraviolet curable resin-coated optical fiber core with an outer diameter of 250 μm. The tensile strength body 28 of the cable portion 22 uses an FRP rod with an outer diameter of 0.4 mm. For 24, a single steel wire having an outer diameter of 1.2 mm was used.

  First, Hytrel 4767-R07 or Hytrel 6347L-01 (which has been added to the outer periphery of the single-core optical fiber 26 at a ratio shown in Table 1 with oleic acid amide or erucic acid amide as a lubricant by a first extruder. In either case, a polyether / polybutylene terephthalate block copolymer trade name, manufactured by Toray DuPont Co., Ltd.) was extrusion coated to form a coating 27 having an outer diameter of 0.9 mm. Next, the single-core optical fiber core wire 26 on which the coating 27 is formed, the two strength members 28, and the support wire 24 are introduced into the second extruder in a state of being arranged in parallel as shown in FIG. Then, non-halogen flame-retardant polyethylene (trade name NUC9739 manufactured by Nippon Unicar Co., Ltd.) was collectively extrusion coated on the outer periphery to produce an optical fiber cable having a total width of about 2 mm and a height of about 5 mm.

Comparative Examples 1-7
An optical fiber cable was manufactured in the same manner as in the above example except that the material for forming the coating 27 was changed as shown in Table 1. In addition to the materials used in the examples, Hytrel 4047 and Hytrel 7247L-01 (both are trade names of polyether / polybutylene terephthalate block copolymer, manufactured by Toray DuPont) are used for the material of the coating 27 did.

  About the optical fiber cable obtained by each said Example and each comparative example, the heat cycle test (-40 degreeC-+85 degreeC, 10 cycles) was done, and the maximum transmission loss increase amount was investigated. In addition, an attempt was made to take out the actually coated single-core optical fiber 26 from the outer sheath 29, and the take-out property was evaluated. Further, with respect to the single-core optical fiber core 26 having the taken-out coating 27, the bending gusset, the protruding amount of the single-core optical fiber core 26 from the coating 27, and the removability of the coating 27 were examined. These results are shown in Table 1 together with the flexural modulus (ASTM D 790) of the material constituting the coating 27.

The tendency of bending gusset is that the single-core optical fiber 26 provided with the coating 27 is wound in a ring having a diameter of 60 mm, held at −30 ° C. for 6 hours, then at 70 ° C. for 6 hours, and then at 20 ° C. We returned and examined and evaluated the condition of bending. The protruding amount of the single-core optical fiber core wire 26 is
The single-core optical fiber core wire 26 provided with the coating 27 was held for 10 cycles in the temperature range of −30 ° C. to 70 ° C., and after aging at 120 ° C. for 24 hours, measurement was performed with a microscope. Furthermore, the removal property of the coating 27 was evaluated by using a hand stripper NO-NIK (φ0.254 mm) (trade name) manufactured by elauss and attempting to remove the coating 27 under the conditions of a removal length of 40 mm and a tensile speed of 500 mm / min.

  As is clear from the above results, the optical fiber cable according to the present invention has good transmission characteristics and good take-out property of the coated optical fiber core 26. In addition, good results were also obtained with respect to the bent gusset, the protruding amount of the optical fiber core, and the coating removal performance of the coated optical fiber core 26.

Sectional drawing which shows 1st Embodiment of the optical fiber cable of this invention. The figure which shows typically the example of wiring of the optical fiber cable of 1st Embodiment. Sectional drawing which shows 2nd Embodiment of the optical fiber cable of this invention. Sectional drawing which shows other embodiment of the optical fiber cable of this invention. Sectional drawing which shows other embodiment of the optical fiber cable of this invention. Sectional drawing which shows an example of the conventional optical fiber cable. Sectional drawing which shows the structure of an optical fiber cord. The figure explaining the removal operation | work of the covering of an optical fiber.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 21 ... Support wire part, 22 ... Cable part, 23 ... Connection part, 24 ... Support wire, 25, 29 ... Outer sheath, 26 ... Single-core optical fiber core, 27 ... Cover, 28 ... Strength body, 201-204 ... Fiber optic cable

Claims (6)

An optical fiber cable comprising an optical fiber core, a tensile body arranged in parallel with the optical fiber core, and a jacket that is collectively extrusion-coated on the outer periphery thereof,
The optical fiber is provided with a coating made of a polymer material having a flexural modulus (ASTM D 790) of 80 MPa to 450 MPa containing 0.5% to 3% by weight of a fatty acid amide lubricant. Fiber cable.   The optical fiber cable according to claim 1, wherein the coating made of the polymer material has a thickness of 50 μm to 400 μm.   3. The optical fiber cable according to claim 1, wherein the fatty acid amide-based lubricant is at least one selected from the group consisting of erucic acid amide, oleic acid amide, stearyl oleylamide and bisoleic acid amide.   4. The optical fiber cable according to claim 1, wherein the polymer material is a polyester-based thermoplastic elastomer.   5. The polyester-based thermoplastic elastomer is at least one of a polyether / polybutylene naphthalate-based thermoplastic elastomer and a polyether / polybutylene terephthalate-based thermoplastic elastomer. The optical fiber cable described in the section.   The optical fiber cable according to any one of claims 1 to 5, wherein the optical fiber core is a single-core optical fiber having an outer diameter of approximately 0.25 mm or less.

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