JPH02226107A - Loose tube type coated optical fiber - Google Patents

Abstract

PURPOSE:To obtain a loose tube coated optical fiber which never damages an actual line in connecting operation and preferable to practical use by making a loose tube of transparent thermoplastic resin and forming a color belt in the longitudinal direction of the tube. CONSTITUTION:The loose tube is made of the transparent thermoplastic resin and the tube is colored in a thin-line or beltlike shape which enables the kind of the coated optical fiber to be identified. The tube is colored in the longitudinal direction of the tube so that optical fibers in the tube are not interrupted from being viewed. The tube is transparent, so the optical fibers in the tube can be recognized visually at the time of postbranching. Consequently, there is no danger of damaging the fibers and postbranching connecting performance is remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a loose tube type optical fiber coated wire, and particularly to a coated optical fiber having good post-branching property.

[Conventional technology]

The loose tube optical fiber core is branched and connected from the cable in which it is laid, as necessary, in order to lead the cable to a new subscriber.

Up until now, when branching and connecting optical fiber cables used for actual lines to cables for new subscribers, damage to the actual lines during the connection work has been a major problem. This damage is particularly dangerous when colored multi-core loose tube core wires are mixed with actual circuits. Since the optical fiber strands inside the tube cannot be visually recognized, there is a concern that the optical fiber strands housed in a spiral shape in the longitudinal direction within the tube may be damaged.

Loose tube core wire is usually made by coating multiple optical fibers and a sherry-like mixture with a tube material, and polybutylene terephthalate resin (PBT), polyamide resin, etc. are generally used as the tube material. It is used. Furthermore, since a large number of tube core wires are accommodated in the cable, the tubes are colored so that connection operations can be performed more effectively by coloring the tubes. However, in conventional colored loose tube core wires, the internal optical fibers cannot be seen through, so disadvantages such as splicing of optical fibers often occur when branching later.

[Problem to be solved by the invention]

Therefore, an object or technical problem of the present invention is to provide a practical method for connecting an optical fiber cable used in an actual line to a cable leading to a new subscriber without damaging the actual line during the connection work. The object of the present invention is to provide a desirable loose tube core wire.

[Means to solve the problem]

As a result of repeated research into methods for solving the above technical problems, the present inventors have found that, although there are restrictions on the resin, the tube of the core wire is made of a transparent resin, and the tube has a longitudinal band-like shape or It was discovered that when coloring a line, there is an unexpectedly excellent practical effect in operations such as branching and connection, leading to the present invention.

That is, the present invention provides a loose tube type optical fiber coated wire in which the loose tube is made of a transparent thermoplastic resin and a colored band is formed in the longitudinal direction of the tube. do.

The optical fiber core wire of the present invention is characterized in that a transparent thermoplastic resin tube and the tube are colored in a thin line or band shape that allows identification of the type of core wire. It is important that the length of the tube is such that viewing through the plurality of optical fibers within the tube is not obstructed. According to the above-mentioned purpose, the colored line or the like may be a solid line, a broken line, a dotted line, etc., as long as it is possible to distinguish wa, and therefore, the colored band in the present invention includes these colored lines.

Normally, optical fiber loose tube core wires are manufactured using an extruder equipped with a cross-radial die, in which a plurality of optical fibers supplied with a sherry-like mixture are continuously fed into the nipple of the die, and at the same time, the nipple The coating resin is continuously melted and extruded from a ring-shaped opening surrounding the tip of the tube to form a cylindrical coating. After forming the adhesive coating, the coating is cooled, for example, in a water bath at a temperature of about 5 to 70°C. In addition, coloring is especially conveniently carried out by applying ink of the desired color by utilizing the running of the core wire at the rear of the aquarium, and at the same time as the coating resin, extruding the colored band resin in the longitudinal direction in a band shape. Although the methods are practical,
You can also attach a colored band after winding the cable.

It is important that the thermoplastic resin for the tube of the loose tube cored optical fiber cable of the present invention be transparent at room temperature. It may be made transparent by selecting conditions, and the thermoplastic resin constituting such a transparent coating layer can be used regardless of whether it is crystalline or amorphous. Typical resins for forming such transparent tubes include, for example, crystalline resins such as polybutylene terethalate (PBT), nylon-12° polyethylene, and amorphous resins such as polycarbonate.

Furthermore, the coloring agents used to color these resin tubes may be organic or inorganic (1) Usually, they are a binder of resins that have a strong affinity or adhesiveness to the tube-forming resin. The tube is colored in a band-like manner by applying it to the tube or by dissolving it in the resin.

[Effect]

In the loose tube type optical fiber core wire of the present invention, since the tube is transparent, the optical fiber strand inside the tube can be seen through the tube at the rear branching, and therefore there is no risk of damaging the strand. The post-branching connectivity is significantly improved.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A bundle of 12 optical fiber wires with a diameter of about 0.3H, which were primarily coated with an ultraviolet curable resin, was sent to the cross of an extruder into a RAD die, and while a mixture for Sherry wipes was supplied to this,
A loose tube core wire was manufactured by extruding and covering transparent nylon-12 as a covering tube material. In the extrusion coating, nylon-12 colored with a common blue pigment color batch is simultaneously extruded from a rad die onto the cloth, and two continuous strips of about 2 cm width are placed on the left and right opposing surfaces of the coating tube. A blue band was formed respectively.

In the extrusion production of this core wire, it was possible to visually observe the condition of the optical fiber and the mixed fabric filling material from the non-colored coating layer, and it was possible to control the amount of filler supplied while observing the condition.

As a result, the loose tube line obtained was practically desirable because there was no risk of substantially damaging the actual line cable during branching work to new subscribers, and it also had excellent transmission performance.

Example 2 The procedure was substantially the same as in Example 1, but only transparent PBT was used as the coating tube material, and instead of application in the rad dye to the blue band cross, a PBT system prepared from a red masterbatch was used. After forming an optical fiber into a loose tube using ink, a continuous thin red line was applied in the longitudinal direction using the movement of the fiber.

The visual coating operation was extremely easy, and the resulting loose tube type optical fiber had extremely good post-branching workability.

〔Effect of the invention〕

Since the loose tube type optical fiber core of the present invention is composed of a transparent tube, there is virtually no damage to the actual line during branching work after the cable is drawn from the cable used in the actual line to a new subscriber. This is extremely desirable for practical purposes.

Claims (1)

[Claims] 1. A loose tube type optical fiber coated wire in which the loose tube is made of a transparent thermoplastic resin and a colored band is formed in the longitudinal direction of the tube.