JP2011237559A - Optical drop cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical drop cable that has a good cicada-resistant effect and excellent characteristics such as mechanical strength.SOLUTION: An optical drop cable 101 includes: an optical fiber core wire 11; tension-resistant members 12a and 12b arranged with a space in between and in parallel to the optical fiber core wire; and an outer sheath 13 enclosing all the aforementioned components. The outer sheath is formed from a composition containing 40-50 pts.mass of magnesium hydroxide (E) and 5-15 pts.mass of a red phosphorus-based flame retardant material (F) in the 100 pts.mass of a base resin comprising 40-60 mass% of a straight-chain low-density polyethylene (A), 20-40 mass% of an ultra-high molecular weight polyethylene (B), 10-20 mass% of an adhesive polymer (C), and 2-8 mass% of an ethylene-vinyl acetate copolymer (D).

Description

  The present invention relates to an optical drop cable used for drawing and wiring from a wiring system cable to a subscriber's house such as a building or a general house, and more particularly to an optical drop cable having a coating excellent in damage resistance.

  With the spread of communication services such as the Internet, FTTH (Fiber To The Home), which connects all sections from a telecommunications carrier to a subscriber's home with optical fiber, is rapidly expanding. In such FTTH, the optical wiring network in the vicinity of the subscriber's house is generally an overhead wiring using a power pole, and the main method is to drop the wiring cable from the wiring pole to the subscriber's house using an optical drop cable. Has been adopted.

  In general, this optical drop cable has a tensile body placed above and below an optical fiber core, a support wire is further placed thereon, and a thermoplastic resin such as polyethylene is collectively coated on the outer periphery thereof. It has a structure with a jacket. A connecting portion (neck portion) is provided between the cable support wire and the tensile body to facilitate separation from the cable support wire portion, and on both side surfaces of the cable jacket, A tearing notch is provided to facilitate removal of the optical fiber.

  By the way, recently, many damages due to cicada have been reported in the optical drop cable, and countermeasures have become an urgent issue. The damage is mainly due to the bearfish, which causes damage to the optical transmission as a result of damaging the optical fiber by piercing the egg drop tube into the optical drop cable.

  Therefore, in order to prevent damage to the optical fiber due to the oviposition tube of the bearfish, for example, a protective member that protects the optical fiber core is embedded in the jacket, or the tip of the tear notch is shifted from the position of the optical fiber core. In the unlikely event that an optical fiber core wire is not damaged even if a spawning tube of a bearfish is pierced into the notch, there have been proposed various measures taken on the cable structure itself (for example, Patent Documents 1 and 2). reference.). The latter is likely to cause the risk of damage by shifting the position of the tip of the notch, because the spawning tube of the bearfish tends to pierce the tearing notch and there is a high risk of damage to the optical fiber if there is an optical fiber core on the extension of the notch tip. I want to lower it. In addition, a structure in which the outer cover is made of, for example, a resin having a specific rebound resilience and wear resistance, and the structure itself is not changed, and the cover material is changed by changing the cover material has been proposed ( For example, see Patent Document 3.)

  However, in the case where the protective member is embedded, the take-out property of the optical fiber core wire is deteriorated and the number of parts increases, so that the manufacturing cost may be increased. In addition, shifting the position of the tip of the notch does not necessarily have an effect of preventing damage caused by the oviposition tube of the bearfish. Furthermore, the one using a specific resin for the jacket material was not fully satisfactory from the viewpoint of achieving both the anti-bacterial effect and other characteristics required for optical drop cables such as mechanical strength. .

JP 2007-72380 A JP 2008-203797 A JP 2009-271538 A

  The present invention has been made in response to the above-described problems of the prior art, has a simple structure, does not require an increase in the number of parts, has an excellent anti-fouling effect, and has an optical drop cable such as mechanical strength. Another object of the present invention is to provide an optical drop cable having good characteristics.

  In order to achieve the above object, an optical drop cable according to the first aspect of the present invention includes an optical fiber core, tensile strength members arranged in parallel with an interval to the optical fiber core, and a collective covering thereof. An optical drop cable comprising: (A) linear low density polyethylene 40-60 mass%, (B) ultrahigh molecular weight polyethylene 20-40 mass%, (C) adhesive polymer 10 (E) Magnesium hydroxide 40-50 parts by mass, and (F) Red phosphorus-based difficulty with respect to 100 parts by mass of 20% by mass and (D) 2-8% by mass of ethylene / vinyl acetate copolymer The jacket is formed of a composition containing 5 to 15 parts by mass of a flame retardant.

An optical drop cable according to a second aspect of the present invention is the optical drop cable according to the first aspect, wherein the component (B) is an ultra-low drop having a density (ASTM D 1505) of 0.960 to 0.970 g / cm ^3. It is characterized by being high molecular weight polyethylene.

  According to a third aspect of the present invention, in the optical drop cable according to the first or second aspect, the component (F) is a red phosphorus flame retardant having an average particle size (JIS R 1629) of 10 to 15 μm. It is a feature.

  The invention according to claim 4 is the optical drop cable according to any one of claims 1 to 3, wherein the composition has a Shore D hardness (JIS K 7215) of 50 or more. It is.

  The invention according to claim 5 is the optical drop cable according to any one of claims 1 to 4, characterized in that the jacket has a tensile strength of 15 MPa or more and an elongation of 300% or more. Is.

  An optical drop cable according to a sixth aspect of the present invention is a cable portion comprising an optical fiber core, a tensile body arranged in parallel with the optical fiber core being spaced apart from each other, and a jacket covering them all together And a support wire portion provided with a support wire for supporting the cable portion, wherein (A) 40-60% by mass of linear low density polyethylene, (B) 0.960-0. 20 to 40% by weight of ultrahigh molecular weight polyethylene having a density of 970 (ASTM D 1505), (C) 10 to 20% by weight of adhesive polymer, and (D) 2 to 8% by weight of ethylene / vinyl acetate copolymer The jacket is formed of a composition containing (E) magnesium hydroxide 40-50 parts by mass and (F) red phosphorus flame retardant 5-15 parts by mass with respect to 100 parts by mass of the base resin. It is characterized by.

  A seventh aspect of the present invention is the optical drop cable according to any one of the first to sixth aspects, wherein the optical drop cable is a fender-proof optical drop cable.

  According to the present invention, the structure is simple, it is not necessary to increase the number of parts, and it has an excellent anti-fouling effect and also has other characteristics required for the optical drop cable such as mechanical strength and the like. A drop cable is obtained.

It is sectional drawing which shows the optical drop cable which concerns on one Embodiment of this invention. It is sectional drawing which shows the modification of the optical drop cable of this invention. It is sectional drawing which shows the other modification of the optical drop cable of this invention. It is sectional drawing which shows the other modification of the optical drop cable of this invention. It is sectional drawing which shows the other modification of the optical drop cable of this invention.

  Embodiments of the present invention will be described below. Although the description will be made based on the drawings, the drawings are provided for illustration only, and the present invention is not limited to the drawings. Moreover, in the following description, the same code | symbol is attached | subjected about the component which has the same or substantially the same function and structure, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a cross-sectional view showing an embodiment of the optical drop cable of the present invention.

  As shown in FIG. 1, the optical drop cable 101 of this embodiment is a cable used for drawing and wiring from a wiring cable installed between utility poles to a subscriber's house such as a building or a general house. The optical drop cable 101 includes a cable portion 10, a support wire portion 20, and a connecting portion 30 that connects them.

  The cable portion 10 is parallel to the single optical fiber core 11 with a space between the single optical fiber core 11 and the upper and lower portions of the single optical fiber core 11 so that the centers of the optical fiber cores 11 are located on substantially the same plane. Strength members 12a and 12b (hereinafter referred to as a tensile strength member 12a above the single-core optical fiber core wire 11) are arranged below the first tensile strength body and the single-core optical fiber core wire 11 made of an arranged steel wire, FRP (fiber reinforced plastic), or the like. The tensile strength member 12b is referred to as a second tensile strength member) and an outer cover 13 that is extrusion-coated on the outside thereof.

  The outer sheath 13 is formed in a substantially rectangular cross section, and a pair of tears are formed on the surface thereof, on both the left and right surfaces of the optical fiber core wire 11, so that the optical fiber core wire 11 can be easily taken out during cable terminal processing. Notches 14a and 14b are provided.

  On the other hand, the support wire portion 20 is composed of a support wire 21 made of a steel wire and the like, and a sheath 22 which is extrusion-coated integrally with the outer cover 13 of the cable portion 10 and the connecting portion 30 on the outer periphery thereof. The covering 22 has a circular cross section.

  And in this embodiment, the jacket 13 of the cable part 10, the coating | cover 22 and the connection part 30 of the support wire part 20 are (A) 40-60 mass% of linear low density polyethylene, (B) Ultra high molecular weight. (E) Hydroxylation with respect to 100 parts by mass of base resin comprising 20 to 40% by mass of polyethylene, (C) 10 to 20% by mass of adhesive polymer, and (D) 2 to 8% by mass of ethylene / vinyl acetate copolymer It is formed with the composition containing 40-50 mass parts of magnesium and 5-15 mass parts of (F) red phosphorus flame retardant.

The linear low density polyethylene (LLDPE) as the component (A) is an α-olefin (propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicocene, 4-methyl-1-pentene, etc.) It is a polyethylene having a density of 0.910 to 0.925 g / cm ³ measured according to JIS K 7112, in which short-chain branches are introduced into the polymer. Specifically, for example, MORETECH 0138N having a density (JIS K 7112) of 0.917 g / cm ³ and a melt flow rate (MFR) (JIS K 7210; 190 ° C., load 2.16 kg) of 1.3 g / 10 min (( The product name of Prime Polymer Co., Ltd.) is used. (A) The linear low density polyethylene (LLDPE) of a component may be used individually by 1 type, and 2 or more types may be mixed and used for it.

As the ultra high molecular weight polyethylene as the component (B), ultra high molecular weight high density polyethylene (UMWHDPE) having a density measured according to ASTM D 1505 of 0.960 to 0.970 g / cm ³ is suitable. Specifically, for example, density (ASTM D 1505) is 0.967 g / cm ³ of Ryubuma L4000, density (ASTM D 1505) is 0.969 g / cm ³ of Ryubuma L3000, density (ASTM D 1505) is 0.966g / Cm ³ Lübmer L5000 (all are trade names manufactured by Mitsui Chemicals, Inc.) and the like are used. (B) The ultra high molecular weight polyethylene of a component may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  The adhesive polymer of component (C) is a polyolefin modified with an unsaturated carboxylic acid or a derivative thereof, that is, an unsaturated carboxylic acid or a derivative thereof introduced into the polyolefin by, for example, a graft reaction. Polyolefins include polyethylene, such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene, as well as ethylene, vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl acetate. , Ethylene / vinyl ester copolymer obtained by copolymerizing vinyl ester such as vinyl laurate, vinyl stearate, vinyl benzoate, vinyl salicylate, vinyl cyclohexanecarboxylate; ethylene, methyl acrylate, ethyl acrylate, acrylic acid Isopropyl, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isobutyl acrylate, dimethyl maleate, maleate Ethylene-acrylic acid ester copolymer with an unsaturated carboxylic acid ester obtained by copolymerizing such as diethyl and the like.

  Examples of the unsaturated carboxylic acid used for the modification include maleic acid, fumaric acid, croconic acid, itaconic acid, citraconic acid, and the like. Derivatives of the unsaturated carboxylic acid include esters of the unsaturated carboxylic acid. , Anhydrides, metal salts, amides, imides and the like. Specific examples of unsaturated carboxylic acid derivatives include maleic acid monoester, maleic acid diester, fumaric acid monoester, fumaric acid diester, itaconic acid monoester, itaconic acid diester, maleic anhydride, fumaric anhydride, itaconic anhydride Etc.

  As the adhesive polymer of component (C), one kind may be used alone, or two or more kinds may be mixed and used. As the adhesive polymer of component (C), a polymer obtained by modifying polyethylene with an unsaturated carboxylic acid or a derivative thereof is preferable, and a polymer obtained by modifying polyethylene with a maleic acid or a derivative thereof is more preferable. Maleic anhydride-modified polyethylene obtained by graft-polymerizing maleic anhydride to polyethylene in the presence of about 1 to 10% by weight of an organic peroxide such as benzoyl peroxide is particularly suitable as an adhesive polymer for component (C). It is. Specific examples of such commercially available maleic anhydride-modified polyethylene include Adtex L6101M (trade name, manufactured by Nippon Polyethylene Co., Ltd.).

As the ethylene / vinyl acetate copolymer (EVA) as component (D), MFR (JIS K 7210; 190 ° C., load 2.16 kg) 0.5-30 g / 10 min, density (JIS K 7112) 0. The thing of 940-0.970g / cm < ³ >, VA content (JIS K 7192) 25-40 mass% is preferable. A specific example of such a commercially available ethylene / vinyl acetate copolymer is, for example, Evaflex EV180 (trade name, manufactured by Mitsui DuPont Polychemical Co., Ltd .; VA content (JIS K 7192) of about 35% by mass) Is mentioned. As the component (D), ethylene / vinyl acetate copolymer (EVA) may be used singly or in combination of two or more.

  Component (A), (B) component, (C) component and (D) component constituting the base resin of the composition is 40-60% by mass of the linear low density polyethylene (A) component. , Preferably 45-55% by mass, (B) component ultrahigh molecular weight polyethylene 20-40% by mass, preferably 25-35% by mass, (C) component adhesive polymer 10-20% by mass, preferably 12 to 18% by mass, and (D) component ethylene / vinyl acetate copolymer is 2 to 8% by mass, preferably 3 to 7% by mass. When the proportion of the linear low density polyethylene as the component (A) is less than 40% by mass, the tensile elongation is lowered, and when it exceeds 60% by mass, the mechanical properties, particularly the tensile strength and the tensile elongation are lowered. Moreover, if the ratio of the ultra high molecular weight polyethylene of (B) component is less than 20 mass%, an antifungal effect will fall, and if it exceeds 40 mass%, tensile elongation will fall. Moreover, if the ratio of the adhesive polymer of (C) component is less than 10 mass%, tensile elongation will fall, and if it exceeds 20 mass%, tensile strength will fall. Further, when the proportion of the ethylene / vinyl acetate copolymer as the component (D) is less than 2% by mass, the cold resistance decreases, and when it exceeds 8% by mass, the tensile strength decreases.

  Moreover, as magnesium hydroxide of (E) component, that whose average particle diameter (JISR1629) is 1.0-1.5 micrometers is especially preferable from a uniform dispersion viewpoint. The magnesium hydroxide may be subjected to surface treatment with a higher fatty acid such as stearic acid, a higher fatty acid such as stearic acid, or a silane coupling agent. By using such surface-treated magnesium hydroxide, the dispersibility when kneading with the base resin can be enhanced. (E) As a preferable commercial product used as the magnesium hydroxide of the component, the average particle diameter (JIS R 1629) surface-treated with stearic acid was 1.3 μm, and the surface was treated with stearic acid. Examples include Magsees N-4 having an average particle size (JIS R 1629) of 1.1 μm (all are trade names manufactured by Kamishima Chemical Co., Ltd.).

  (E) The compounding quantity of the magnesium hydroxide of a component is with respect to 100 mass parts of total amounts of (A) component, (B) component, (C) component, and (D) component which are the structural components of the base resin mentioned above. It is 40-50 mass parts, Preferably it is 45-50 mass parts. When the blending amount is less than 40 parts by mass, the flame retardancy becomes insufficient. Moreover, when it exceeds 50 mass parts, a mechanical characteristic and cold resistance will fall.

  Further, as the red phosphorus flame retardant as the component (F), those having an average particle diameter (JIS R 1629) of 10 to 15 μm are particularly preferable from the viewpoint of uniform dispersion. Specifically, Nova Red 120UF, Nova Red 120UFA, Nova Red 280A, Nova Quel W100 (all of which are trade names manufactured by Rin Chemical Industry Co., Ltd.) and the like are used.

  The blending amount of the red phosphorus flame retardant of the component (F) is 100 parts by mass of the total amount of the components (A), (B), (C) and (D) which are constituent components of the base resin described above. It is 5-15 mass parts with respect to this, Preferably it is 8-13 mass parts. If the blending amount is less than 5 parts by mass, the flame retardancy is lowered.

  In addition to the above components, the composition includes additives such as antioxidants, ultraviolet absorbers, processing aids, lubricants, colorants, stabilizers, etc., as long as they do not inhibit the effects of the present invention. Can be blended. For example, as an antioxidant, 1 to 3 parts by mass of a phenolic antioxidant, for example, ADK STAB AO-60 (trade name, manufactured by ADEKA) can be blended with respect to 100 parts by mass of the base resin.

  The composition can be easily prepared by uniformly mixing (dry blending) or kneading the above-described components using a conventional kneader such as a Banbury mixer, tumbler, pressure kneader, kneading extruder, mixing roller, or the like. it can. Then, the composition obtained in this way is collectively extrusion coated onto the outer periphery of the single-core optical fiber cores 11, the two strength members 12 a, 12 b and the support wires 21 arranged in parallel as shown in FIG. 1. The jacket 13 of the cable part 10, the covering 22 of the support line part 20, and the connecting part 30 can be formed.

  In addition, it is preferable that the composition has a Shore D hardness (hereinafter simply referred to as Shore D hardness) of 50 or more as measured based on JIS K 7215. If the Shore D hardness is less than 50, the effect of preventing damage caused by the oviduct such as bearfish is reduced. The Shore D hardness is more preferably 55 or more and 65 or less.

  In the optical drop cable 101 of the present embodiment, the single-core optical fiber core wire 11 is not particularly limited, and the outer periphery of the optical fiber is coated with silicone resin or ultraviolet curable resin, and the outer periphery is further nylon. A thermoplastic elastomer blended with a resin or a colorant, for example, a polybutylene naphthalate thermoplastic elastomer or a polybutylene terephthalate thermoplastic elastomer is used.

  The first and second strength members 12a and 12b may be made of steel wire, FRP, aramid fiber such as poly-p-phenylene terephthalamide fiber, polyester fiber such as polyethylene terephthalate fiber, nylon, and the like. Examples thereof include fibers and composite materials obtained by converging and binding these fibers with a polyester-acrylate resin or the like.

  In the optical drop cable 101 of this embodiment, since the jacket 13 is formed of the specific composition as described above, it has a high fender effect. In other words, even if an oviposition tube such as a bearfish is inserted into the first and second notches 14a and 14b, the tip thereof does not pierce deeply into the jacket 13 and the optical fiber is damaged. Is prevented.

  Moreover, the jacket 13 is excellent not only in mechanical strength (tensile strength, elongation, etc.) but also in characteristics such as flexibility, wear resistance, flame retardancy, etc. Therefore, the optical drop cable 101 is high. In addition to the anti-fouling effect, it has the characteristics required for this type of optical drop cable. The jacket 13 preferably has a tensile strength measured in accordance with JIS C 3005 of 15 MPa or more and an elongation of 300% or more.

  Moreover, in the optical drop cable 101 of this embodiment, since a new member such as a protective member for protecting the optical fiber core wire 11 is not required, the product price is not increased.

  The present invention is not limited to the embodiment described above, and can be implemented in various forms without departing from the gist of the present invention. For example, like the optical drop cable 102 shown in FIG. 2, it may be comprised only by the cable part 10 of the optical drop cable 101 shown in FIG.

  Further, in the optical drop cable 101 shown in FIG. 1, one single-core optical fiber core wire 11 is embedded in the jacket 13, but a plurality of (for example, the optical drop cable 103 shown in FIG. Two single-fiber optical fiber ribbons 11 in the example of FIG. 3 may be embedded. Further, as in the optical drop cables 104 and 105 illustrated in FIGS. 4 and 5, a plurality of optical fiber strands are arranged in parallel instead of the single-core optical fiber core 11, and the outer periphery thereof is collectively covered. One or a plurality of optical fiber ribbons 15 (one in the example of FIG. 4 and two in the example of FIG. 5) may be embedded. In this case, the arrangement method of the optical fiber ribbon 15 is not particularly limited.

  Further, the number of strength members 12a and 12b and the shape and number of tear notches 14a and 14b are not particularly limited.

  In each of these optical drop cables 102 to 105, etc., the jacket 13 is formed of a composition having high damage resistance and excellent mechanical strength, flexibility, wear resistance, flame retardancy, and the like. Therefore, like the optical drop cable 101, it has an excellent anti-fouling effect and also has other characteristics required for this type of optical drop cable.

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

Examples 1-14, Comparative Examples 1-14
Linear low-density polyethylene (trade name: MORETEC 0138N, manufactured by Prime Polymer Co., Ltd.), ultra-high molecular weight high-density polyethylene (trade name: Lübmer L4000, manufactured by Mitsui Chemicals, Inc.), maleic anhydride-modified polyethylene (MAHPE) as an adhesive polymer (Trade name Adtex L6101M manufactured by Nippon Polyethylene Co., Ltd.), ethylene / vinyl acetate copolymer (trade name EVAFLEX EV180 manufactured by Mitsui DuPont Polychemical Co., Ltd.), low-density polyethylene, magnesium hydroxide (Kamishima Chemical Industries ( Co., Ltd. Product name: Magseees N-6), Red phosphorus flame retardant (Product name: NOVARED 120UF) manufactured by Phosphorus Chemical Industries, Ltd., and hindered phenol-based antioxidant (as manufactured by ADEKA Co., Ltd.) ADK STAB AO-60), carbon black as colorant Tokai Carbon Co., Ltd. product name Carbon Seast G116), as processing aid, fatty acid amide (Nippon Yushi Co., Ltd. product name Alflow P-10), and as a lubricant, stearic acid type lubricant (manufactured by Kawaken Fine Chemical Co., Ltd.) Using the name LE-5), the components shown in Tables 1 to 4 were uniformly kneaded to obtain a resin composition.

  Subsequently, the optical drop cable of the structure shown in FIG. 1 was manufactured using the obtained resin composition. First, a single-core optical fiber ribbon 11 having an outer diameter of 250 μm, two tensile members 12a and 12b made of aramid FRP (aramid fiber reinforced plastic) having an outer diameter of 0.5 mm, and zinc plating having an outer diameter of 1.2 mm. A support wire 21 made of a single steel wire is introduced into an extruder in a parallel state as shown in FIG. 1, and the resin composition is collectively extrusion coated on the outer periphery thereof, and tearing notches 14a and 14b are formed on the surface. An optical drop cable having a width of about 2.0 mm and a height of about 5.8 mm was manufactured.

  About the optical drop cable obtained by each said Example and each comparative example, various characteristics were evaluated by the method shown below. The mechanical properties (tensile strength, elongation, and hardness (Shore D)) were determined at 180 ° C. × 10 ° C. by using the resin composition obtained in each Example and each Comparative Example separately from the cable production. A test sheet was produced by heating and pressing under conditions of a pressure of 20 MPa for a minute and measured.

[Tensile strength and elongation]
It measured based on JISK6251.
[Hardness (Shore D)]
It was measured with a JIS K 6253 type D durometer.
[Oxygen index]
It measured based on JISK7201-2.
[Brittle temperature (cracking temperature)]
It measured based on the JIS C 3005 embrittlement test.
[Corrosion resistance]
The optical drop cable was laid for 30 days outdoors during the period when the bearfish appeared, and the optical fiber that was not broken due to the invasion of the spawning tube of the bearfish was passed, and the cable that was broken was rejected.
[Flame retardance]
A vertical tray combustion test defined in JIS C 3521 was performed, and after ignition, the case where self-extinguishing was not performed up to the upper end (1800 mm) was determined to be acceptable, and the case where self-extinguishing was not performed was determined to be unacceptable.

  These results are shown in the lower column of Tables 1 to 4.

  As is clear from Tables 1 to 4, in the examples, it was confirmed that the outer jacket had good mechanical properties (tensile strength of 15 MPa or more, elongation of 300% or more) and hardness. . In addition, the optical drop cable of the example was remarkably excellent in damage resistance and also had good flame retardancy. On the other hand, the optical drop cable of the comparative example was inferior in mechanical strength, cold resistance, damage resistance, and flame retardancy.

  DESCRIPTION OF SYMBOLS 10 ... Cable part, 11 ... Single-core optical fiber core wire, 12a, 12b ... Strength body (1st and 2nd strength body), 13 ... Jacket | cover, 14a, 14b ... Notch for tearing (1st and 2nd (Notch), 15 ... optical fiber ribbon, 20 ... support line portion, 21 ... support line, 22 ... coating, 101 to 105 ... optical drop cable.

Claims (7)

An optical drop cable comprising an optical fiber core, tensile strength members arranged parallel to the optical fiber core at intervals, and a jacket covering them all together,
(A) Linear low density polyethylene 40-60% by mass, (B) Ultra high molecular weight polyethylene 20-40% by mass, (C) Adhesive polymer 10-20% by mass, and (D) Ethylene / vinyl acetate copolymer According to the composition containing (E) 40-50 parts by mass of magnesium hydroxide and (F) 5-15 parts by mass of the red phosphorus flame retardant with respect to 100 parts by mass of the base resin composed of 2-8% by mass of the coalescence, An optical drop cable characterized in that a jacket is formed. The optical drop cable according to claim 1, wherein the component (B) is ultrahigh molecular weight polyethylene having a density (ASTM D 1505) of 0.960 to 0.970 g / cm ³ .   The optical drop cable according to claim 1 or 2, wherein the component (F) is a red phosphorus flame retardant having an average particle size (JIS R 1629) of 10 to 15 µm.   The optical drop cable according to any one of claims 1 to 3, wherein the composition has a Shore D hardness (JIS K 7215) of 50 or more.   5. The optical drop cable according to claim 1, wherein the jacket has a tensile strength of 15 MPa or more and an elongation of 300% or more. An optical fiber core, a cable portion including a tensile body arranged in parallel with a gap to the optical fiber core, a jacket covering them all at once, and a support wire for supporting the cable portion are provided. An optical drop cable having a support line part,
(A) Linear low density polyethylene 40-60% by mass, (B) Ultra high molecular weight polyethylene 20-40% by mass having a density of 0.960-0.970 (ASTM D 1505), (C) Adhesive polymer (E) 40-50 parts by mass of magnesium hydroxide and (F) red phosphorus with respect to 100 parts by mass of base resin comprising 10-20% by mass and (D) 2-8% by mass of ethylene / vinyl acetate copolymer An optical drop cable characterized in that the jacket is formed of a composition containing 5 to 15 parts by mass of a flame retardant based on flame retardant.   The optical drop cable according to any one of claims 1 to 6, wherein the optical drop cable is a fender-proof optical drop cable.

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