JP5902007B2 - Optical fiber cable and optical fiber cable manufacturing method - Google Patents

Description

  The present invention relates to an optical fiber cable and a method for manufacturing an optical fiber cable.

  2. Description of the Related Art Conventionally, an optical fiber cable in which a plurality of optical fibers are bundled using a binding member such as a colored thread or a plastic tape to form an optical fiber unit and a plurality of the optical fiber units are mounted has been put into practical use.

  In addition, when the optical fiber cable is disassembled and when the optical fiber is branched, the coarse winding string is welded to the holding winding tape by the heat of the outer casing to simultaneously remove the press winding tape and the coarse winding string. It has been proposed (see, for example, Patent Document 1).

JP 2009-1116017 A

  By the way, in the conventional optical fiber cable, the bundling member in which the optical fibers are bundled can be easily unwound, and when the bundling member is unexpectedly unwound during the intermediate branching operation, the take-out property and the distinguishability may be deteriorated.

  In order to improve this, an optical fiber unit in which a plurality of optical fibers are wound using a plurality of bundling members made of a heat bonding material and the intersections of the bundling members are heat-sealed can be considered. According to this optical fiber unit, the bundling member is not easily unraveled unexpectedly, and the distinguishability at the time of intermediate branching work can be improved.

  However, in a manufacturing process of an optical fiber cable using a plurality of binding members made of a heat bonding material, when a polyethylene material that is often used as a cable jacket is used, the resin temperature at the time of extrusion molding is 140 ° C. to 220 ° C. It will be about. This heat may cause the bundling member to be heated above its melting point, and the bundling members of adjacent optical fiber units may be bonded together. As a result, there is a problem that the take-out property (handleability) of the optical fiber is deteriorated in the intermediate post-branching operation.

  In view of the above problems, the object of the present invention is to form an optical fiber unit using a bundling member made of a heat-bonding material. An object of the present invention is to provide an optical fiber cable and a method of manufacturing the optical fiber cable that can maintain good takeout performance of the fiber.

  According to one aspect of the present invention, a plurality of optical fibers are bundled and separated from each other using a core part and a bundling member that covers the core part and has a covering part that has a lower melting point than the core part. A plurality of optical fiber units; a plurality of optical fiber units; and a first outer jacket having a lower melting point than the covering portion of the binding member; a first outer jacket; An optical fiber cable comprising a second jacket having a higher melting point than that of the first jacket is provided.

  In one embodiment of the present invention, the melting point of the first jacket may be 80 ° C. to 120 ° C., and the melting point of the second jacket may be 120 ° C. to 130 ° C.

  In one aspect of the present invention, in each of the optical fiber units, a plurality of optical fibers may be bundled using one binding member, or a structure in which a plurality of the bundled optical fiber units are twisted together may be used. good.

  In one aspect of the present invention, in each of the optical fiber units, a plurality of optical fibers may be bundled using a plurality of binding members, and the intersections of the binding members may be heat-sealed.

  In one embodiment of the present invention, the melting point of the second jacket may be equal to or higher than the melting point of the covering portion.

  According to another aspect of the present invention, an optical fiber unit is formed by bundling a plurality of optical fibers using a binding member having a core portion and a covering portion provided to cover the core portion and having a melting point lower than that of the core portion. Using a first resin having a lower melting point than that of the covering portion, and by extrusion molding, a step that is higher than the melting point of the first resin and lower than the melting point of the covering portion. A step of forming a first jacket by covering the periphery of a plurality of optical fiber units at a temperature of 1 and a second resin having a melting point higher than that of the first resin by extrusion molding. And forming a second jacket by coating the first jacket at a second temperature equal to or higher than the melting point of the resin of 2. The method of manufacturing an optical fiber cable is provided.

  In another aspect of the present invention, the step of producing the optical fiber unit may bundle a plurality of optical fibers using a single binding member.

  In another aspect of the present invention, the step of manufacturing the optical fiber unit includes a step of bundling a plurality of optical fibers using a plurality of bundling members so that the bundling members have crossing portions, and having a core portion higher than a melting point of the covering portion. The intersection may be heat-sealed by heating at a temperature lower than the melting point.

  In another embodiment of the present invention, the melting point of the first resin may be 80 ° C to 120 ° C, and the melting point of the second resin may be 120 ° C to 130 ° C.

  In another aspect of the present invention, the melting point of the second resin may be equal to or higher than the melting point of the covering portion.

  In another aspect of the present invention, the step of forming the first jacket and the step of forming the second jacket may be performed simultaneously by coextrusion.

  According to the present invention, when an optical fiber unit is formed using a bundling member made of a heat bonding material, adjacent optical fiber units are separated from each other, and the optical fiber is easily taken out in an intermediate post-branching operation. It is possible to provide an optical fiber cable and a method for manufacturing the optical fiber cable.

It is sectional drawing of the cable longitudinal direction which shows an example of the optical fiber cable which concerns on embodiment of this invention. It is a perspective view which shows an example of the optical fiber unit which concerns on embodiment of this invention. It is a perspective view which shows another example of the optical fiber unit which concerns on embodiment of this invention. It is sectional drawing of the longitudinal direction which shows an example of the binding member which concerns on embodiment of this invention. It is a table | surface showing the evaluation result of the 1st and 2nd Example of the optical fiber cable which concerns on embodiment of this invention, and a comparative example. It is sectional drawing of the cable longitudinal direction which shows an example of the optical fiber cable which concerns on other embodiment of this invention.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Further, the embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention includes the material, shape, structure, The layout is not specified as follows. The technical idea of the present invention can be variously modified within the scope of the claims.

(Structure of optical fiber cable)
As shown in FIG. 1, the optical fiber cable according to the embodiment of the present invention includes a plurality of optical fiber units 10a and 10b that are separated from each other without being bonded to each other, and a plurality of optical fiber units 10a and 10b. A covered first jacket (sheath) 1 and a second jacket (sheath) 2 covering the periphery of the first jacket 1 are provided.

  As the material of the first jacket 1 and the second jacket 2, for example, a resin such as high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), or polypropylene (PP) can be used. It is. The thicknesses of the first jacket 1 and the second jacket 2 are each about 1 mm.

  A press-wound tape 3 is disposed between the plurality of optical fiber units 10 a and 10 b and the first jacket 1. The material of the presser winding tape 3 is a thermoplastic resin such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) or nylon (registered trademark), or thermosetting such as epoxy. Resin can be used.

  A pair of tear strings (lip cords) 5 a and 5 b are embedded in the first jacket 1. As the lip cords 5a and 5b, a twisted yarn made of polyester, a fiber cord such as an aramid fiber or glass fiber, or the like can be used.

  A pair of strength members (tension members) 4a and 4b are embedded in the second jacket 2 in a direction perpendicular to the straight line connecting the lip cords 5a and 5b. As the strength members 4a and 4b, metal wires such as steel wires, fiber reinforced plastics (FRP), or the like can be used. Further, the tensile strength members 4a and 4b are not limited to linear bodies, but may be strip-shaped bodies. The band-like body is a long band-like one having a flat cross section, an elliptical shape, or a rectangular shape such as a rectangle.

  As shown in FIG. 2, the optical fiber unit 10a includes a bundle of optical fibers 11a, one bundling member 12a wound around the bundle of optical fibers 11a, or a plurality of (here, two) ) Bundling members 12a and 12b.

  The bundle of optical fibers 11a is, for example, a collection of 20 optical fiber cores having a diameter of 0.25 mm. As the optical fiber 11a, a core wire such as an optical fiber strand, an optical fiber core wire, or an optical fiber tape core wire can be adopted. In the embodiment of the present invention, the number of optical fibers 11a and the types of optical fibers 11a are not particularly limited.

  As shown in FIG. 2, when one bundling member 12a is wound, a unique color is given so as to be distinguishable from other optical fiber units 10b.

  On the other hand, when a plurality of bundling members 12a and 12b are wound as shown in FIG. 3, the same color or different colors may be attached to each other so as to be distinguishable from other optical fiber units 10b.

  In FIG. 3, the binding members 12a and 12b are spirally wound around the bundle of optical fibers 11a in opposite directions, and the crossing portions (cross-binding portions) T of the binding members 12a and 12b are bonded by heat sealing. Has been. The adhesive strength at the intersection T between the bundling members 12a and 12b is such that the bundling members 12a and 12b can be easily removed by hand when the bundling members 12a and 12b are not unintentionally released. Therefore, it is possible to prevent the binding members 12a and 12b from being unintentionally unwound and impairing the discrimination between the optical fiber unit 10a and other optical fiber units 10b. Furthermore, at the time of the intermediate rear branching operation, the intersecting portion T of the bundling members 12a and 12b can be removed by hand to widen the extraction portion, and the optical fiber 11a can be easily extracted.

  The pitch between the intersecting portions T of the binding members 12a and 12b is preferably equally spaced in order to improve the discrimination in the intermediate rear branch, and is preferably 40 mm to 200 mm, for example. The narrower the pitch is less than 80 mm, the more difficult it is to take out the optical fiber 11a during the intermediate branching operation. On the other hand, the visibility of the binding members 12a and 12b becomes worse as the pitch exceeds 200 mm.

  As shown in FIG. 4, the binding members 12 a and 12 b include a plurality of core portions 122 that extend in the cable longitudinal direction, and a covering portion that covers the outer periphery of the core portion 122 and has a melting point lower than the melting point of the core portion 122. 121. The difference between the melting point of the core part 122 and the melting point of the covering part 121 is preferably about 20 ° C. or more. The melting point of the core part 122 is preferably about 160 ° C., and the melting point of the covering part 121 is preferably about 90 ° C. to 130 ° C. Further, the covering portion 121 is required not to be bonded to the optical fiber 11a even if it is melted by heating, or to have a low adhesive force even if bonded, and not to deteriorate the jacket layer of the optical fiber 11a.

  For each of the core part 122 and the covering part 121, for example, high melting point resin such as polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), polypropylene fiber, polyamide fiber (registered trademark nylon, etc.), polyester High melting point fibers such as fibers (PET fibers, etc.), or high melting point tapes or films such as PET, PP, etc., thermoplastic resins that can be repeatedly softened and solidified by heating and cooling, such as polyethylene (PE ), Ethylene vinyl acetate copolymer (EVA), ethylene ethyl acrylate copolymer (EEA) or other materials having a low melting point, or a thermoplastic resin or rubber as a base, which can be repeatedly softened and solidified by heating and cooling. Possible so-called hot-melt contact Or the like can be used as covered with agents.

  The optical fiber unit 10b shown in FIG. 1 is similar to the optical fiber unit 10a in that one or a plurality of binding members 12c and 12d are wound around a bundle of optical fibers 11b and the intersection T is thermally fused. It is bundled. The plurality of optical fiber units 10a and 10b may be twisted together or may be assembled without being twisted.

  Here, the first jacket 1 has a melting point (for example, about 80 ° C. to 120 ° C.) lower than the melting point (about 90 ° C. to 130 ° C.) of the covering portion 121 of the binding members 12a to 12d of the optical fiber units 10a and 10b. Have

  Further, the second jacket 2 has a melting point (for example, about 120 ° C. to 130 ° C.) higher than the melting point of the first jacket 1 (about 80 ° C. to 120 ° C.). Further, the melting point of the second jacket 2 may be equal to or higher than the melting point of the covering portion 121 of the binding members 12a to 12d of the optical fiber units 10a and 10b, or may be lower than the melting point of the covering portion 121.

  In the intermediate post-branching operation for the optical fiber cable according to the embodiment of the present invention, the first jacket 1 and the second jacket 2 are torn and peeled to a predetermined length by pulling the lip cords 5a and 5b. take. And the optical fiber 11a, 11b can be taken out by peeling off the intersection T of the binding members 12a-12d of the exposed optical fiber units 10a, 10b.

  According to the optical fiber cable according to the embodiment of the present invention, since the optical fiber units 10a and 10b are separated from each other without being bonded, the take-out properties of the optical fibers 11a and 11b at the time of intermediate post branching work are good. Can be maintained.

(Optical fiber cable manufacturing method)
Next, an example of the manufacturing method of the optical fiber cable which concerns on embodiment of this invention is demonstrated. In addition, the manufacturing method of the optical fiber cable shown below is an example, and is not specifically limited to this.

  (A) A plurality of binding members 12 a and 12 b each having a core portion 122 and a covering portion 121 provided so as to cover the core portion 122 and having a melting point lower than that of the core portion 122 are prepared. Then, as shown in FIG. 3, a plurality of binding members 12a and 12b are wound around a bundle of a plurality of optical fibers 11a so as to have a crossing portion T spirally.

  (B) Next, the bundle of optical fibers 11a around which the binding members 12a and 12b are wound is carried into a heating device such as an electric furnace, such as a Kanthal furnace (not shown), an electric heater, or a hot-air heating furnace. Heating is performed at a temperature (for example, about 130 ° C. to 140 ° C.) that is equal to or higher than the melting point of the covering portion 121 that constitutes 12a and 12b and lower than the melting point of the core portion 122. As a result, the covering portions 121 of the binding members 12a and 12b are melted, and the binding members 12a and 12b are bonded to each other at the intersection T by heat fusion. On the other hand, since the core part 122 does not melt, the shape of the binding members 12a and 12b is maintained.

  (C) The optical fiber unit 10a around which the binding members 12a and 12b are wound is naturally cooled after being carried out of the heating device. Thereby, the coating | coated part 121 solidifies and the adhesion state of the cross | intersection part T of the binding members 12a and 12b is maintained. In this way, the optical fiber unit 10a is manufactured. In addition, as shown in FIG. 2, when the one binding member 12a is wound around the optical fiber unit 10a, the above-described heating and cooling steps can be omitted. Further, the optical fiber unit 10b shown in FIG. 1 is manufactured in the same manner as the optical fiber unit 10a. The optical fiber unit 10b can be simultaneously manufactured in parallel with the optical fiber unit 10a.

  (D) As shown in FIG. 1, a plurality of optical fiber units 10a and 10b are assembled. The periphery of the plurality of optical fiber units 10a and 10b is pressed with a presser winding tape 3 and introduced into an extruder not shown together with the lip cords 5a and 5b.

  (E) Then, by using a resin having a melting point (for example, about 80 ° C. to 120 ° C.) lower than the melting point (for example, about 90 ° C. to 130 ° C.) of the covering portion 121 constituting the binding members 12a and 12b, by extrusion molding. The first jacket 1 is formed by covering the periphery of the optical fiber units 10 a and 10 b with the press-wound tape 3. The temperature of the resin at the time of extrusion molding is set to a temperature (for example, 100 ° C.) that is equal to or higher than the melting point of the resin and lower than the melting point of the covering portion 121 constituting the binding members 12a and 12b. For this reason, the covering part 121 of the binding members 12a to 12d of the optical fiber units 10a and 10b is not melted, and the binding members 12a to 12d can be prevented from being melted at portions other than the intersection T.

  (F) Next, the optical fiber units 10a and 10b covered with the first outer jacket 1 are introduced into an extruder (not shown) together with the strength members 4a and 4b. Then, by using a resin having a melting point higher than the melting point of the resin constituting the first jacket 1 (for example, about 120 ° C. to 130 ° C.), the periphery of the first jacket 1 is covered by extrusion molding. 2 outer casings 2 are formed. The temperature of the resin at the time of extrusion molding is set to a temperature equal to or higher than the melting point of the resin (for example, about 140 ° C. to 220 ° C.). In addition, the temperature of the resin at the time of extrusion molding may be equal to or higher than the melting point of the covering portion 121 constituting the binding members 12a and 12b, or may be a temperature lower than the melting point of the covering portion 121. Since the first jacket 1 is interposed between the optical fiber units 10a and 10b and the second jacket 2, the heat at the time of extrusion molding of the second jacket 2 is transmitted to the optical fiber units 10a and 10b. Conduction can be suppressed. For this reason, the covering part 121 of the binding members 12a to 12d of the optical fiber units 10a and 10b is not melted, and the binding members 12a to 12d can be prevented from being melted at portions other than the intersection T.

  (G) Then, it cools by water cooling etc. and the optical fiber cable shown in FIG. 1 is completed.

  As described above, according to the method for manufacturing an optical fiber cable according to the embodiment of the present invention, the first jacket 1 having a melting point lower than the melting point of the covering portion 121 is covered at a temperature lower than the melting point of the covering portion 121. The first outer cover 1 and the second outer cover 2 are coated with a second outer cover 2 having a melting point higher than the melting point of the first outer cover at a temperature equal to or higher than the melting point of the second outer cover 2. Thus, it is possible to prevent the heat-bonding of the binding members 12a to 12d at the time of each of the two extrusion moldings. As a result, it is possible to manufacture an optical fiber cable in a state where the optical fiber units 10a and 10b are separated without being bonded.

  Furthermore, since a material having a melting point higher than that of the first jacket 1 can be used as the second jacket 2, the surface of the optical fiber cable can be made uniform with less roughness.

  In addition, although the case where the extrusion molding of the 1st jacket 1 and the 2nd jacket 2 was performed separately was demonstrated, the 1st jacket 1 and the 2nd jacket 2 are the extruders which can be co-extruded. And may be formed simultaneously by coextrusion. In this case, the number of man-hours can be reduced as compared with the case where the first outer cover 1 and the second outer cover 2 are separately extruded.

(Example)
As shown in FIG. 1, two optical fiber cables according to the first and second examples of the embodiment of the present invention and an optical fiber cable according to the comparative example are bundled in a bundle of a plurality of optical fibers 11a and 11b. The binding members 12a to 12d are respectively wound to form optical fiber units 10a and 10b, and a first outer cover 1 and a second outer cover 2 are simultaneously formed by coextrusion around the optical fiber units 10a and 10b. did.

  In both of the optical fiber cables according to the first and second embodiments and the optical fiber cable according to the comparative example, the press-wound tape 3 is a polyester tape, and the first outer cover 1 is 1 mm thick Easy Processing Polyethylene (EPPE). (Registered Trademark), the second outer jacket 2 was a linear low density polyethylene having a thickness of 1 mm. The melting point of the covering portion 121 of the binding members 12a to 12d was 125 ° C.

  In the optical fiber cables according to the first and second embodiments and the optical fiber cable according to the comparative example, as shown in FIG. 5, the melting points of the first jacket 1 are 82 ° C., 102 ° C., and 124 ° C., respectively. The melting points of the second jacket 2 are all 124 ° C.

  In the optical fiber cables according to the first and second embodiments and the optical fiber cables according to the comparative examples, the temperature of the resin at the time of extrusion molding of the first jacket 1 is about 100 ° C., which is about 20 ° C. higher than the respective melting points. The temperature of the resin at the time of extrusion molding of the second jacket 2 is about 140 ° C.

  FIG. 4 shows the evaluation results of the cable transmission characteristics and the fusion between the optical fiber units 10a and 10b for the optical fiber cables according to the first and second examples and the optical fiber cable according to the comparative example. The cable transmission characteristic was a white circle (◯) when the loss variation was 0.1 dB / km or less. Both the optical fiber cables according to the first and second examples and the optical fiber cable according to the comparative example had good loss fluctuations of 0.1 dB / km or less.

  Next, regarding the fusion between the optical fiber units 10a and 10b, a white circle (◯) is obtained if there is no fusion, and a white triangle (Δ) if there is a slight fusion. In the optical fiber cables according to the first and second examples, it was confirmed that the optical fiber units 10a and 10b were not fused at all. On the other hand, in the optical fiber cable according to the comparative example, it was confirmed that the optical fiber units 10a and 10b were slightly fused.

(Other embodiments)
As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the embodiment of the present invention, the slotless optical fiber cable is shown as shown in FIG. 1, but the type of the optical fiber cable is not particularly limited as long as it has an optical fiber unit. For example, the present invention can be applied to a slot type optical fiber cable such as an SZ slot type optical fiber cable or a tape slot type optical fiber cable.

  In the embodiment of the present invention, a structure having two optical fiber units 10a and 10b as shown in FIG. 1 has been described, but the number of optical fiber units is not particularly limited. Further, the number and type of optical fibers included in each optical fiber unit may be the same or different.

  In the embodiment of the present invention, the number of binding members wound around the optical fiber units 10a and 10b and the presence / absence of intersections are not particularly limited. For example, as shown in FIG. 2, one binding member 12a may be wound without forming an intersection, and two binding members 12a, 12b have an intersection T as shown in FIG. It may be wound or three or more binding members may be wound.

  Further, in the embodiment of the present invention, as the binding members 12a and 12b, the string-like structure in which a plurality of core portions 122 are collectively covered with the covering portion 121 as shown in FIG. 4 has been described. Not. For example, a double structure in which the outer periphery of one core part is covered with a covering part may be used. Moreover, the structure which made the core part tape shape or a film shape, and coat | covered this core part with the coating | coated part may be sufficient. Moreover, the structure which twisted two or more things of the double structure which coat | covered the outer periphery of the core part with the coating | coated part may be sufficient.

  In the embodiment of the present invention, as shown in FIG. 3, the case where the two binding members 12a and 12b are spirally wound around the bundle of the optical fibers 11a has been described. However, the binding members 12a and 12b are described. The number and the winding method are not particularly limited as long as they can be wound so as to have the intersection T. For example, one binding member 12a may be wound spirally, and another binding member 12b may be vertically attached. In addition, the two binding members 12a and 12b may be spirally wound in opposite directions, and another single binding member may be vertically attached.

  Further, in the embodiment of the present invention, the structure in which the strength members 4a and 4b are embedded in the first jacket 1 as shown in FIG. 1 has been described, but as shown in FIG. 6, the strength members 4a and 4b. May be embedded in the second outer jacket 2.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... 1st jacket 2 ... 2nd jacket 3 ... Pressing winding tape 4a, 4b ... Strength body 5a, 5b ... Lip cord 10a, 10b ... Optical fiber unit 11a, 11b ... Optical fiber 12a-12d ... Bundling member 121 ... Covering part 122 ... Core part

Claims (7)

A plurality of optical fiber units that are bundled and separated from each other using a binding member having a core portion and a covering member that is provided to cover the core portion and has a melting point lower than that of the core portion; ,
A first jacket covering the periphery of the plurality of optical fiber units and having a lower melting point than the covering portion of the binding member;
A second jacket covering the periphery of the first jacket and having a higher melting point than the first jacket ;
Equipped with a,
In each of the optical fiber units, the plurality of optical fibers are bundled using a plurality of the bundling members, and the intersection of the bundling members is heat-sealed,
An optical fiber cable , wherein the melting point of the second jacket is equal to or higher than the melting point of the covering portion . The optical fiber cable according to claim 1, wherein the binding member has a structure in which a plurality of the core portions are dispersed in the covering portion . The melting point of the first jacket is 80 ° C. to 120 ° C .;
The optical fiber cable according to claim 1 or 2 , wherein the melting point of the second jacket is 120C to 130C. Bundling the plurality of optical fibers using a bundling member having a core part and a covering part provided to cover the core part and having a melting point lower than that of the core part, and producing an optical fiber unit;
Collecting a plurality of the optical fiber units;
Around the plurality of optical fiber units at a first temperature that is equal to or higher than the melting point of the first resin and lower than the melting point of the covering portion by extrusion molding using a first resin having a lower melting point than the covering portion. Forming a first envelope by coating
A second resin having a melting point higher than that of the first resin is used to coat the first outer cover by extrusion molding at a second temperature equal to or higher than the melting point of the second resin. Forming a jacket of the
Only including,
The step of producing the optical fiber unit includes:
Bundling the plurality of optical fibers using a plurality of the bundling members so that the bundling members have crossing portions,
By heat-sealing the intersecting portion by heating at a temperature not lower than the melting point of the covering portion and lower than the melting point of the core portion,
The method for manufacturing an optical fiber cable , wherein the melting point of the second resin is equal to or higher than the melting point of the covering portion . The optical fiber cable manufacturing method according to claim 4 , wherein the binding member has a structure in which a plurality of the core portions are dispersed in the covering portion . The melting point of the first resin is 80 ° C. to 120 ° C .;
The method for producing an optical fiber cable according to claim 4 or 5 , wherein the melting point of the second resin is 120 ° C to 130 ° C. The optical fiber according to any one of claims 4 to 6 , wherein the step of forming the first jacket and the step of forming the second jacket are simultaneously performed by coextrusion. Cable manufacturing method.

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