JPS585409B2 - Hikari Eye Bar - Setsuzokubuno Gaibuhogohokiyouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for protecting and reinforcing optical fiber connections.

In recent years, with the rapid increase in the amount of information, there has been a strong desire for practical use of optical communication that involves multiplex transmission, and various research and development efforts are underway.

The lines used for this optical communication are usually made of glass fiber such as optical glass or quartz glass, and are coated with thermoplastic resin on the outside for reinforcement.

When connecting these externally coated optical fibers, it is required to be easy to work with, be compact, lightweight, and be stable over time, and the present invention provides protection and reinforcement for the joint that satisfies these requirements. The present invention provides a method.

The present invention involves removing the outer covering of two outer covering optical fibers, integrally covering the connected portion and a part of the outer covering optical fiber with a heat-shrinkable tube having a double layer of thermoplastic resin on the inner surface, and heating. By shrinking, the optical fiber connection part is protected and reinforced at once.

The purpose of providing a double layer of thermoplastic resin on the inner surface of the heat shrink tube is that it is a single thermoplastic resin that has mechanical strength and is compatible with and adheres to the part to be protected and reinforced. This is because it is very difficult to select a material that provides good airtightness and watertightness.

Examples will be explained below.

Example 1 FIG. 1 shows the state of optical fiber connections.

1 is an outer coated optical fiber, 2 is an outer coat of the optical fiber, 3 is an optical fiber, 4 is a connecting part of the optical fiber,
Reference numeral 5 indicates a matching agent made of an organic material with a refractive index close to that of the optical fiber, which is used to prevent light loss at the connection surface of the optical fiber.

In this embodiment, the optical fiber 3 is made of quartz and has an outer diameter of 200 μm.
1 External coating 2 is polybutylene lenticule crate with a thickness of 30 mm.
The 0 μm 1 optical fiber connection portion 4 is a heat-shrinkable tube made of cross-linked polyethylene that is heat-shrinked and connected.
Its outer diameter is approximately 1 mm.

FIG. 2 shows a heat-shrinkable tube with a double layer of thermoplastic on the inside surface.

6 is a heat-shrinkable tube having a double layer of thermoplastic resin on the inner surface, 7 is the heat-shrinkable tube, 8 is a thermoplastic resin coated or charged on the inner surface of the heat-shrinkable tube 7, and 9 is further the heat-shrinkable tube. The thermoplastic resin applied or introduced to the inner surface of the thermoplastic resin 8 is shown.

In this embodiment, the heat-shrinkable tube 7 is made of cross-linked polyethylene, and the inner double thermoplastic resins 8 and 9 are each made of ethylene.
These are vinyl acetate copolymer and chlorosulfonated polyethylene.

Note that the heat-shrinkable tube 6, which has double thermoplastic resin 8 and 9 on its inner surface, either completely loses its internal space due to shrinkage due to heating and melting of the internal thermoplastic resin, or
It has a very narrow structure.

FIG. 3 shows a state in which the optical fiber connection portion shown in FIG. 1 is protected and reinforced from the outside with the triple-structured heat-shrinkable tube 6 shown in FIG. 2.

This protection and reinforcement method is as shown in FIG.
A heat-shrinkable tube 6 having double thermoplastic resins 8 and 9 is placed on the inside so as to partially cover the tube, and heated with a commercially available dryer.

Then, the heat-shrinkable tube 7 contracts and the thermoplastic resins 8 and 9 inside are melted, so that the tube 7 is in close contact with the optical fiber connecting portion 4, the coating removed portion of the externally coated optical fiber 1, and a part of the externally coated optical fiber 1 without any gaps.

After cooling, the airtightness and watertightness of the connecting portion 4 and the like are maintained due to the good compatibility and adhesion between the chlorosulfonated polyethylene of the innermost thermoplastic resin 9 and the polybutylene terephthalate of the outer coating 2 of the optical fiber.

In addition, for mechanical protection and reinforcement, the innermost thermoplastic resin 9, chlorosulfonated polyethylene, is thin but not strong, and has good compatibility and adhesion with the ethylene-vinyl acetate copolymer of the inner thermoplastic resin 8. The inner thermoplastic resin 8 and the heat-shrinkable tube 7, which are stronger due to their superior properties, are sufficient.

This method can also be easily performed in one operation.

(2) Protection and reinforcement can be achieved even if there are different parts such as the optical fiber connection part 4, the outer coating removed part, or the outer coating optical fiber 1, or if there are irregularities such as irregularities or sizes of each part.

- Even if the optical fiber is bent, the triple-structured heat-shrinkable tube 6 itself is flexible, so there is no problem during insertion, heat-shrinking, etc.

- If a transparent material is used as in the case of this embodiment, the internal state can be observed even after the work is completed.

It also has various advantages such as, and becomes an effective means for protecting and reinforcing the optical fiber connection part 4 and its surroundings, which has been one of the concerns.

The material of the heat-shrinkable tube 7 is polyethylene,
Resins such as polyolefins such as polyvinyl chloride, polyvinylidene fluoride, fluorinated ethylene, propylene copolymers, ethylene vinyl acetate copolymers, etc. alone or mixtures with plasticizers, etc., and crosslinked products thereof, or silicone rubber, Rubbers such as ethylene-propylene rubber alone or in mixtures with fillers are useful, and the internal thermoplastic resin 8 may include polyethylene, ethylene-propylene copolymer, chlorinated polyethylene, chlorosulfonated polyethylene, ethylene. Thermoplastic resins such as vinyl acetate copolymer, ethylene ethyl acrylate, vinyl chloride, polypropylene, polycarbonate, and polyamide resins alone or in mixtures with plasticizers, etc. are useful, and the thermoplastic resin 9 inside thereof is as follows: Thermoplastic resins such as low molecular weight polyethylene, chlorosulfonated polyethylene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate, polybutyne, polyisobutylene, petroleum rosin, microcrystal wax, asphalt polyamide resin, etc. alone or mixtures with plasticizers, etc. is useful.

Although the combination of materials with such a triple structure can be obtained arbitrarily, it is preferable to use a thermoplastic material 8 that is more easily softened than the material of the heat-shrinkable tube 7, and a thermoplastic material that is more easily softened and flowable in the innermost part. Preferably, materials 9 are combined.

[Brief explanation of the drawing]

FIG. 1 shows the state of optical fiber connections. 1 is the outer coating fiber, 2 is the outer coating of the optical fiber, 3 is the optical fiber, 4 is the connecting part of the optical fiber, 5
indicates a matching agent. FIG. 2 shows a heat shrink tube with a double layer of thermoplastic on the inside surface. 6 is a heat-shrinkable tube having a double layer of thermoplastic resin on the inner surface, 7 is the heat-shrinkable tube, 8 is the thermoplastic resin on the inner surface, and 9 is the thermoplastic resin on the inner surface. Figure 3 shows a state in which a heat-shrinkable tube 6 having a double layer of thermoplastic resin 8 and 9 on the inside is covered from the outside over the connected portion 4 of the connected outer covering fibers and its surroundings, and is protected and reinforced by heat shrinkage. show.

Claims (1)

[Claims] 1. A heat-shrinkable tube characterized by using a resin tube whose inner surface is coated with or charged with a thermoplastic resin, and whose inner surface is further coated with or filled with a thermoplastic resin that is more easily softened than the resin. A method for protecting and reinforcing optical fiber connections.