JP2002267897A - Optical fiber cord - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent decrease in the smoothness of the sheath surface when a material prepared by compounding a powdery non-halogen flame retardant such as ammonium polyphosphate in a non-halogen polymer such as a polyester elastomer is used as the composition to constitute the sheath of an optical fiber cord. SOLUTION: A silicone compound such as silicone-grafted polyethylene is compounded by 0.05 to 2 wt.% to the composition constituting the sheath 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cord, and more particularly to an optical fiber cord having excellent flame retardancy and good surface slippage.

[0002]

2. Description of the Related Art At present, a plasticized polyvinyl chloride (PVC) material is used for a sheath of an optical fiber cord. However, PVC-based materials generate harmful dioxins and chlorine-containing gases during incineration, and their use is being reviewed. For this reason, the sheath of the optical fiber cord also needs to be made of a substitute resin material other than the PVC-based material, but since PVC has good flame retardancy,
These alternative resin materials are also required to have the same flame retardancy as PVC-based materials.

[0003] From such a viewpoint, a non-halogen-based polymer containing no halogen element, such as polyethylene, polypropylene, polyester elastomer, nylon, or the like, is used as a base polymer, and magnesium hydroxide, aluminum hydroxide, polyphosphorus is used as the sheath composition. Use of a flame retardant composition containing 20 to 50% by weight of a non-halogen flame retardant such as ammonium acid or melamine cyanurate has been studied.

[0004] In this flame-retardant composition, although flame retardancy comparable to that of a PVC-based material is obtained, each of the above-mentioned non-halogen-based flame retardants is in the form of a powder having a particle size of several μm to several tens μm. Since the compounding amount is relatively large, particles of these halogen-free flame retardants appear on the sheath surface, and the sheath surface is roughened.

[0005] For this reason, such an optical fiber cord has poor surface slipperiness, and in some cases, such as when the optical fiber cord is entangled at the time of a jumper operation using the same, there has been a problem.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical fiber cord having a sheath made of a non-halogen-based polymer as a base polymer and a powdered non-halogen-based flame retardant blended with the base polymer. To improve the performance.

[0007]

This problem is solved by forming the sheath with a composition in which a powdered non-halogen flame retardant and a silicone compound are mixed with a non-halogen polymer and a non-halogen polymer. The amount of the silicone compound is preferably 0.05 to 2% by weight of the total amount of the composition, and the coefficient of static friction of the optical fiber cord is preferably 0.4 or less.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
Examples of the non-halogen polymer used as the base polymer of the composition constituting the sheath of the optical fiber cord of the present invention include polyolefin polymers such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer and ethylene-ethyl acrylate copolymer, and polyesters. Polymers containing no halogen element in the molecule, such as thermoplastic elastomers such as elastomers and polyurethane elastomers, and nylons such as nylon 11 and nylon 12, are used, and one or more blend polymers of these are used.

As the powdered non-halogen flame retardant, one or a mixture of two or more of magnesium hydroxide, magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate, melamine cyanurate and the like is used. The amount of the powdered non-halogenated flame retardant to be blended is determined by the required flame retardancy and the type of the powdered non-halogenated flame retardant to be used.
It is in the range of about weight%, but is not limited to this range.

As the silicone compound used for improving the slipperiness, a compound having a siloxane bond in the molecule is used. Specifically, silicone-grafted polyethylene, silica silicone, silicone powder,
One or a mixture of two or more such as silicone gum and silicone oil is used. The compounding amount of this silicone compound is 0.05 to 2% by weight of the total amount of the composition,
If the content is less than 0.05% by weight, no slippage improving effect is obtained,
If the amount is more than 10% by weight, the amount becomes excessive, and the silicone compound exudes to the sheath surface, and the suitability for printing on the sheath surface decreases.

[0011] In addition to the above composition, additives such as a filler, an antioxidant, and a coloring agent can be appropriately compounded as required.

FIG. 1 shows an example of an optical fiber cord according to the present invention. Reference numeral 1 denotes an optical fiber core. The optical fiber core 1 is an optical fiber having a diameter of 0.5 mm in which an optical fiber having a diameter of 250 μm is coated with an ultraviolet curable resin, nylon 12, or the like. An aramid fiber functioning as a tension member is provided around the optical fiber 1.
A plurality of reinforcing fiber bundles 2, 2,... Such as carbon fiber and glass fiber are vertically attached.

A sheath 3 is provided around the reinforcing fiber bundles 2, 2,.
m loose optical fiber cord. And
This sheath 3 is made of the composition described above. That is, the above-described composition is kneaded to form a pellet, which is put into an extruder, and is extrusion-coated on the reinforcing fiber bundles 2, 2,... Using a crosshead die.

In the optical fiber cord of the present invention, a small amount of the silicone compound oozes out on the surface of the sheath 3, the slipperiness is improved on the surface of the sheath 3, and the optical fiber cord entangles at the time of a jumper operation or the like. There is no. Also,
Since the slipperiness of the surface of the sheath 3 is improved, the coefficient of static friction of the optical fiber cord is 0.4 or less.

The measurement of the coefficient of static friction in the optical fiber cord of the present invention is performed as shown in FIG. First,
Two or more layers of the optical fiber cord 12 of the present invention are tightly wound around a bobbin 11 having a diameter of 60 to 300 mm and fixed. Then, another optical fiber cord 13 of the present invention having a length of about 500 mm is prepared, a weight 4 having a weight of 50 g is attached to one end thereof, and a weight 14 is used as a guide with a recess at the contact portion of the optical fiber cord 12 wound around the bobbin 11. Then, the other end of the optical fiber cord 13 is attached to a push-pull gauge 15 placed horizontally.

After the optical fiber cord 13 is at rest, the maximum tension (T) when the push-pull gauge 15 is gently retracted is measured, and the static friction coefficient (μ) is calculated by the following equation (I).

[0017]

(Equation 1)

It has been found that if the coefficient of static friction of the optical fiber cord thus obtained is 0.4 or less, it is possible to avoid a decrease in workability due to sticking of the optical fiber cord.

Hereinafter, specific examples will be described. A sheath composition to be a sheath having the composition shown in Table 1 was prepared, and a loose-type fiber cord having a structure shown in FIG. 1 was manufactured using the sheath composition.
The coefficient of static friction of these optical fiber cords was measured by the method described above, and the flame retardancy was evaluated based on the success or failure of the horizontal combustion test specified in JIS C 3005. Table 1 shows the results.

[0020]

[Table 1]

From the results shown in Table 1, when the amount of the silicone compound is 0.05 to 2%, the coefficient of static friction is 0.4 or less. However, when 3% by weight of silicone-grafted polyethylene was blended (Test No. 5), the printability on the surface of the sheath was reduced although the coefficient of static friction was 0.4 or less.

[0022]

As described above, the optical fiber cord of the present invention is obtained by compounding a silicone compound into the composition constituting the sheath. Therefore, the powdery non-halogen flame retardant is contained in the composition. Even if it is blended, the slipperiness of the surface of the sheath is kept good, and inconvenience such as entanglement of the optical fiber cord does not occur at the time of jumper work or the like.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an optical fiber cord of the present invention.

FIG. 2 is a schematic configuration diagram showing a method of measuring a static friction coefficient in the present invention.

[Explanation of symbols]

 3. Sheath

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/3492 C08K 5/3492 C08L 83/00 C08L 83/00 101/00 ZAB 101/00 ZAB (72) Inventor Tetsuo Hayano 1440, Misaki, Sakura-shi, Chiba Prefecture Inside Fujikura Sakura Works, Inc. 2-3-1 Otemachi Nippon Telegraph and Telephone Corporation (72) Inventor Masao Tachikura 2-3-1 Otemachi, Chiyoda-ku, Tokyo F-term within Nippon Telegraph and Telephone Corporation 2H050 BB04S BC04 BC17 4J002 BB031 BB061 BB071 BB121 CF001 CK021 CL001 CL011 CP032 CP172 DE076 DE146 DH056 EU196 FD136 FD202 GP02

Claims (3)

[Claims] 1. An optical fiber cord having a sheath made of a composition in which a powdered non-halogen flame retardant and a silicone compound are blended with a non-halogen polymer. 2. The optical fiber cord according to claim 1, wherein the content of the silicone compound in the composition is 0.05 to 2% by weight. 3. The optical fiber cord according to claim 1, wherein the coefficient of static friction is 0.4 or less.