JPH0476448B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical fiber housing spacer used for optical fiber cables, optical fiber composite cables, etc., and a method for manufacturing the same.

(Prior Art) FIG. 1 shows a cross-sectional view of an example of an optical fiber storage spacer. In the drawings, 1 indicates a central tensile strength body made of a single or stranded metal wire such as steel or copper; 2
is a polyolefin resin layer with a spiral groove 5 on the outer periphery for storing the optical fiber, and is formed in one layer or two layers as shown in the figure. Conventionally, extruded high-density polyethylene was used in both cases. ing.

(Problems to be Solved) In the conventional optical fiber storage spacer described above, high-density polyethylene is extruded on the outer periphery of the central tensile strength member 1, so that distortion during extrusion of the high-density polyethylene and during cooling occur. Since the strain caused by the contraction of the high-density polyethylene remains at the interface between the central tensile strength member 1 and the high-density polyethylene, the adhesion between the two is weak.

Therefore, optical fiber cables using such spacers are optical fibers in which the high-density polyethylene on the central tensile strength member contracts or expands due to tension during installation, various external forces after installation, heat, etc. may have an adverse effect on the properties of the

(Means for Solving the Problems) The present invention provides an improved spacer for storing optical fibers that solves the above-mentioned problems, and a method for manufacturing the same. Optical fiber storage in which the polyolefin resin layer in contact with the central tensile strength member contains at least 5% adhesive polyolefin resin and is bonded to the metal wire of the central tensile strength member through chemical bonding. The second feature is that after preheating the central tensile strength member made of metal wire, a
% or more of an adhesive polyolefin resin is extruded.

(Example) In the optical fiber storage spacer of the present invention, when the polyolefin resin layer 2 provided on the outer periphery of the central tensile strength member 1 has a two-layer structure as shown in FIG. Contacting inner resin layer 3
A polyolefin-based adhesive resin or a resin in which 5% or more of a polyolefin-based adhesive resin is added to high-density polyethylene is extruded, and a spiral optical fiber storage groove 5 is formed on the high-density polyethylene. The outer resin layer 4 is formed by extrusion processing.

Further, such a polyolefin resin layer 2 may be formed by extrusion processing of a polyolefin adhesive resin without using high-density polyethylene.

In any case, by containing at least 5% or more polyolefin-based adhesive resin in the inner layer 3 in contact with the central tensile strength member 1, the adhesive effect with the central tensile strength member 1 is exhibited, and the adhesion strength is improved. Depending on the required level, the amount of adhesive resin added may be 5 to 5.
You can adjust it between 100%.

To manufacture the spacer as described above, 5 to 50% of polyolefin-based adhesive resin is placed on the center tensile strength member 1.
Although 100% resin can be directly extruded,
If the resin is extruded while the central tensile strength member 1 is preheated with a gas flame, hot air, etc. to bring it close to the extrusion temperature at the time of extrusion, the adhesion between the two will be further improved, which is extremely effective.

(Experiment example) A conventional optical fiber storage spacer with an outer diameter of 9.2 mmφ, which is made by extruding high-density polyethylene for both the inner and outer resin layers on a steel wire with a diameter of 1.4 mmφ, and a spacer with a diameter of 1.4 mmφ.
Polyolefin adhesive resin (Mitsui Petrochemical, Admer LBO30) is applied as an inner resin layer on the steel wire.
Extruded high-density polyethylene on top of the outer diameter
The adhesion force was measured for the spacer of the present invention having a diameter of 9.2 mm.

As shown in Figure 2, the adhesion force was measured by fixing one end of the exposed center tensile strength member and evaluating the maximum pulling force when pulling out a 25 mm long polyolefin resin layer at 50 mm/min.

The result was that the conventional spacer weighed 4 to 5 kg/25 mm, while the spacer of the present invention weighed 15 to 20 kg/25 mm.
The number has reached 3 to 4 times. This dramatic improvement in adhesion is due to the chemical bond between the functional groups contained in the adhesive polyolefin resin such as Admer LBO30 and the metal surface.

In addition, when extruding the inner layer, the central tensile strength body is 1.4 mm.
It was confirmed that adhesion was further improved by preheating the φ steel wire with hot air at approximately 400°C.

(Effects of the Invention) According to the above-described spacer for storing optical fibers of the present invention, at least the layer of the polyolefin resin layer that is in contact with the central tensile strength member contains 5% or more of adhesive resin, so that it is in close contact with the central tensile strength member. This improves the strength and eliminates negative effects on the optical fiber during and after installation of the optical fiber cable.

In addition, since polyolefin resin is used as the adhesive resin, it can be easily mixed with high-density polyethylene.
It is possible to adjust the adhesion strength by adjusting the amount added.

Furthermore, by preheating the central tensile strength member, it is possible to reduce processing strain occurring at the interface of the resin extruded thereon, further improving adhesion.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of an optical fiber storage spacer, and FIG. 2 is an explanatory diagram of a method for measuring adhesion force. DESCRIPTION OF SYMBOLS 1... Central tensile strength body, 2... Polyolefin resin layer, 3... Inner resin layer, 4... Outer resin layer, 5
...Spiral groove.

Claims (1)

[Scope of Claims] 1. A spacer for storing optical fibers comprising a polyolefin-based resin layer having a spiral groove for storing optical fibers on the outer periphery on a central tensile member, wherein the central tensile member is a metal wire; At least the layer in contact with the central tensile strength member of the resin layer contains 5% or more of an adhesive polyolefin resin,
A spacer for storing optical fibers, characterized in that it is bonded to a metal wire of a central tensile strength member through chemical bonding. 2. Claims characterized in that the polyolefin resin layer consists of two layers, the inner layer in contact with the central tensile strength member contains 5% or more of adhesive polyolefin resin, and the outer layer is made of high-density polyethylene. The optical fiber storage spacer according to item 1. 3 After preheating the central tensile strength body made of metal wire,
A method for producing an optical fiber storage spacer, which comprises extruding a polyolefin resin containing 5% or more of an adhesive polyolefin resin on the outer periphery of the spacer.