JPS632084B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical communication cable using an FRP (glass fiber reinforced plastic) coated optical communication line.

Recently, optical communication lines with FRP coating around the optical fiber have been proposed. This FRP-coated optical communication line has superior mechanical properties such as tensile force and lateral pressure compared to ordinary nylon-coated optical communication lines, and the difference in linear expansion coefficient between the FRP coating and the optical fiber is small, so optical transmission can withstand temperature changes. It has the advantage that changes in characteristics are small. Furthermore, since this FRP-coated optical communication line has high mechanical strength, it has the advantage that multiple lines can be twisted together to form a cable without a tension member.

However, when constructing an optical communication cable by twisting multiple FRP-coated optical communication wires together, the FRP coating is hard, so it may rub during twisting or when it is repeatedly bent after being made into a cable. Damage due to contact may occur, resulting in defects in mechanical strength. Also, by twisting
When FRP coated optical communication lines are in direct contact,
Another problem is that the FRP coating is easily damaged when subjected to impact. In addition, since FRP-coated optical communication wires have high rigidity, even if they are twisted together and wrapped with a sheath, if the wrapping is loose or the temperature rises, the cable will be damaged. There is also the problem that the twist returns to its original form at the ends, making it impossible to obtain the desired flexibility. moreover,
When FRP coated optical communication wires are twisted together and a thermoplastic resin sheath is coated on top of the twisted FRP coated optical communication wires, the linear expansion coefficient of the thermoplastic resin sheath is considerably larger than that of the FRP coated optical communication wire. Due to longitudinal contraction, the strands of FRP-coated optical communication lines protrude from the ends of the sheath, resulting in damage to the cable connections and terminals.

An object of the present invention is to provide an optical communication cable that eliminates the various drawbacks described above when constructing a cable using FRP-coated optical communication lines.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

Figure 1 is used for the optical communication cable of the present invention.
An FRP-covered optical communication line is shown. This optical communication line 1 is
Optical fiber 2 made of quartz glass or multicomponent glass
On the outer periphery, primary coat 3, buffer layer 4, FRP
A coating 5 and a hot melt adhesive layer 6 are sequentially coated. The FRP coating 5 is made by hardening a large number of glass fibers aligned in the same direction as the optical fiber 2 with a thermosetting resin such as unsaturated polyester, and the glass fiber content is preferably 60% by weight or more.
It is 80% by weight or more. Hot melt adhesive layer 6
is made of a resin that is adhesive to both the FRP coating 5 and the thermoplastic resin sheath described below, such as ethylene acrylic acid copolymer, ethylene-ethyl acrylate binary copolymer, ethylene-vinyl acetate-vinyl alcohol. A terpolymer, an ethylene-vinyl acetate copolymer, an ethylene-glycidine methacrylate-vinyl acetate terpolymer, a metal ionomer resin, etc. are used. This hot melt adhesive layer 6 is thinly provided on the outer periphery of the FRP coating 5 by extrusion or coating.

FIG. 2 shows an optical communication cable according to an embodiment of the present invention, and this cable is similar to the one shown in FIG.
Seven FRP-coated optical communication lines 1 are twisted together, and the outer periphery of the fiber-covered optical communication lines 1 is covered with a thermoplastic resin sheath 7 made of polyethylene, polyvinyl chloride, or the like. The hot-melt adhesive layer 6 of the optical communication line 1 located on the outer periphery is melted by the heat during extrusion coating of the thermoplastic resin sheath 7, and the FRP coating 5 and the thermoplastic resin sheath 7 are bonded together.
and are glued together.

Since the optical communication cable of the present invention has the above configuration, it has the following effects. i.e. FRP
Since coated optical communication lines have a hot melt adhesive layer on their outer periphery, even if these communication lines rub against each other or other objects, the FRP coating will not be damaged and mechanical strength will not deteriorate. It is possible to construct a highly reliable cable without any problems. Also located on the outside
Since the FRP-coated communication wire and the thermoplastic resin sheath are bonded to each other, the twist of the FRP-coated communication wire is fixed by the thermoplastic resin sheath, which can prevent untwisting at the end of the cable. It is also possible to prevent the FRP-coated optical communication wire strand from protruding from the end of the wire.

[Brief explanation of the drawing]

Figure 1 is used for the optical communication cable of the present invention.
FIG. 2 is a cross-sectional view showing an example of an FRP-coated optical communication cable. FIG. 2 is a cross-sectional view of an optical communication cable according to an embodiment of the present invention. 1...FRP coated optical communication line, 2...Optical fiber,
5...FRP coating, 6...hot melt adhesive layer,
7...Thermoplastic resin sheath.

Claims (1)

[Claims] 1 An optical communication line is made by providing an FRP (glass fiber reinforced plastic) coating around the optical fiber and further coating the outer periphery with a hot melt adhesive layer.
A light beam characterized in that a plurality of optical communication lines are twisted together, a thermoplastic resin sheath is extruded around the outer periphery, and the FRP coating of the optical communication line and the thermoplastic resin sheath are bonded via the hot melt adhesive layer. communication cable.